Patient transport device having auxiliary wheel override assembly - Patent application

Abstract

The patient transport apparatus includes a support structure including a base and a patient support deck. The patient transport apparatus also includes a plurality of wheels and a braking system operable between a braked state and a released state. The patient transport apparatus further includes a brake input device configured for user engagement to change operation of the braking system between the braked state and the released state. The patient transport apparatus also includes an auxiliary wheel assembly including auxiliary wheels and an actuator configured to move the auxiliary wheels between a plurality of auxiliary support positions, including a deployed position and a stowed position. Additionally, the patient transport apparatus includes an override assembly for moving the auxiliary wheels away from the deployed position toward the stowed position in response to movement of the braking system from the released state toward the braked state.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority to and the entire benefit of U.S. Provisional Patent Application No. 63 / 417,069, filed October 18, 2022, the entire disclosure of which is incorporated herein by reference. [Background technology]

[0002] Patient transport devices, such as hospital beds, stretchers, cots, wheelchairs, and transport chairs, facilitate patient care in medical settings. A conventional patient transport device includes a support structure having a patient support deck on which a patient is supported, wheels that allow the patient transport device to move along the floor, and a braking system having a brake to lock the patient transport device in motion.

[0003] At least some known braking systems include a manual foot pedal mounted to a support structure to engage or disengage the brakes. Often, the braking system includes a linkage having a plurality of links, each of which is operatively coupled to a brake such that movement of one link causes movement of the other links and corresponding engagement or disengagement of all of the brakes.

[0004] Additionally, patient transport devices often include an auxiliary wheel assembly that includes at least one deployable wheel configured to engage a floor surface to at least partially support the patient transport device. Challenges can exist associated with braking the patient transport device while these deployable wheels are in contact with the floor surface.

[0005] A patient transport device that addresses one or more of the above-mentioned challenges is desirable. Summary of the Invention

[0006] One general aspect of the present disclosure includes a patient transport apparatus. The patient transport apparatus includes a support structure including a base and a patient support deck, and a plurality of wheels coupled to the base to support movement of the patient transport apparatus across a floor surface. The patient transport apparatus also includes a braking system including a linkage coupled to one or more of the plurality of wheels. The braking system is operable between a braked state that prevents movement of the base along the floor surface and a released state. The patient transport apparatus further includes a brake input device in communication with the linkage and configured for user engagement to change operation of the braking system between the braked state and the released state. The linkage is in a braking state when the braking system is in the braking state, and the brake input device is further configured to move the linkage between a neutral state and a steering state when the braking system is in the released state. The patient transport apparatus also includes an auxiliary wheel assembly including auxiliary wheels, an axle assembly coupled to the base for pivotal movement relative to the base and supporting the auxiliary wheels, and an actuator configured to move the axle assembly and auxiliary wheels between a plurality of auxiliary support positions. The plurality of auxiliary support positions include a deployed position in which the auxiliary wheels engage the floor surface to at least partially support movement of the patient transport device across the floor surface, and a stowed position in which the auxiliary wheels are spaced apart from the floor surface. The patient transport device further includes an override assembly coupled to the linkage of the braking system and to the auxiliary wheel assembly, the override assembly configured to move the auxiliary wheels from the deployed position to the stowed position and at least partially disengage the auxiliary wheels from the floor surface in response to movement of the linkage from the steering state toward one of the neutral state and the brake state.

[0007] Another general aspect of the present disclosure provides a patient transport apparatus comprising: a support structure including a base and a patient support deck; a plurality of wheels coupled to the base for supporting movement of the patient transport apparatus over a floor surface; a braking system including a linkage coupled to one or more of the plurality of wheels and operable between a braked state to prevent movement of the base along the floor surface and a released state; a brake input device in communication with the linkage and configured for user engagement to change operation of the braking system between the braked state and the released state; and an auxiliary wheel assembly coupled to the support structure for moving the auxiliary wheels and a plurality of auxiliary support positions. an auxiliary wheel assembly comprising an actuator configured to move the auxiliary wheels away from the deployed position toward the stowed position in response to movement of the braking system from a released state toward a braked state, the plurality of auxiliary support positions including a deployed position in which the auxiliary wheels engage the floor surface to at least partially support movement of the patient transport device across the floor surface, and a stowed position in which the auxiliary wheels are spaced apart from the floor surface; and an override assembly coupled to the linkage of the braking system and the auxiliary wheel assembly, the override assembly responsive to movement of the braking system from a released state toward a braked state to move the auxiliary wheels away from the deployed position toward the stowed position to simultaneously prevent movement of the base along the floor surface in the braked state and at least partially disengage the auxiliary wheels from the floor surface. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a patient transport device including an auxiliary wheel assembly. [Figure 2] FIG. 2 is a side view of the patient carrier of FIG. 1. [Figure 3] FIG. 1 is a perspective view of a portion of a patient transport device showing a braking system. [Figure 4] FIG. 1 is a top view of a portion of a patient transport device showing the braking system. [Figure 5A] FIG. 1 is a cross-sectional view of a caster assembly that can be used with a braking system having a brake in a braking state. [Figure 5B]FIG. 10 is a cross-sectional view of a caster assembly that can be used with a braking system having a brake in a released state. [Figure 6A] FIG. 1 is a detailed perspective view of a portion of the braking system shown in a released state with the linkage in a neutral position. [Figure 6B] FIG. 2 is a detailed perspective view of a portion of the braking system shown in a braking state. [Figure 6C] FIG. 10 is a detailed perspective view of a portion of the braking system shown in a released state with the linkage in a steering position. [Figure 7] FIG. 1 is a block diagram of components of an electromechanical braking system of some examples of patient transport devices. [Figure 8A] 1 is a schematic partial side view of a patient transport device including an auxiliary wheel assembly with the auxiliary wheels in a stowed position. [Figure 8B] 1 is a schematic partial side view of a patient transport device including an auxiliary wheel assembly with the auxiliary wheels in a deployed position. [Figure 8C] 1 is a schematic partial side view of a patient transport device including an auxiliary wheel assembly, the auxiliary wheels in another configuration in a deployed position. [Figure 9] FIG. 302D is a partial schematic side view of a patient transport device including an auxiliary wheel assembly and a spring cartridge for biasing the auxiliary wheels toward a deployed position 302D. [Figure 10] FIG. 1 is a schematic partial side view of a patient transport device including an override assembly for moving auxiliary wheels away from a deployed position (A) toward a stowed position (B) in response to movement of a braking system from a released state toward a braked state. [Figure 11A] FIG. 1 is a perspective view of an example of an override assembly including an auxiliary wheel assembly in a deployed position and an override linkage in an extended state. [Figure 11B] FIG. 1 is a perspective view of an override assembly including an auxiliary wheel assembly in an intermediate position and an override linkage in an intermediate state. [Figure 11C]FIG. 1 is a perspective view of an auxiliary wheel assembly in a stowed position and an override assembly including an override linkage in a folded position. [Figure 12] FIG. 1 is a perspective view of an example of an auxiliary wheel assembly including a suspension system. [Figure 13] FIG. 13 is a development view of FIG. [Figure 14A] FIG. 11B is a side view of the auxiliary wheel assembly and override assembly of FIG. 11A shown against a floor surface. [Figure 14B] FIG. 11C is a side view of the auxiliary wheel assembly and override assembly of FIG. 11B shown against a floor surface. [Figure 14C] FIG. 11D is a side view of the auxiliary wheel assembly and override assembly of FIG. 11C shown against a floor surface. [Figure 14D] FIG. 1 is a side view of an auxiliary wheel assembly with one or more auxiliary wheels in a deployed position due to operation of an actuator. [Figure 14E] FIG. 10 is a side view of an auxiliary wheel assembly with one or more auxiliary wheels in an intermediate position due to operation of an actuator. [Figure 14F] FIG. 10 is a side view of an auxiliary wheel assembly with one or more auxiliary wheels in a stowed position due to operation of an actuator. [Figure 15A] FIG. 1 is a partial perspective view of one example of an override assembly. [Figure 15B] FIG. 15B is an exploded view of the override assembly of FIG. 15A. [Figure 16A] FIG. 10 is a partial front view of a patient transport device including a linkage of a braking system disposed on a first base rail, with the braking system in a released state and the linkage in a steered state. [Figure 16B] FIG. 10 is a partial front view of a patient transport device including a linkage of a braking system disposed on a first base rail, with the braking system in a released state and the linkage in a neutral state. [Figure 16C]1 is a partial front view of a patient transport device including a linkage of a braking system disposed on a first base rail, the linkage being in a braked state; FIG. [Figure 17A] FIG. 15B is a partial top view of the auxiliary wheel assembly and override assembly of FIG. 15A with the actuator in an operating position. [Figure 17B] FIG. 15B is a partial top view of the auxiliary wheel assembly and override assembly of FIG. 15A with the actuator between an operating position and an override position. [Figure 17C] FIG. 15B is a partial top view of the auxiliary wheel assembly and override assembly of FIG. 15A with the actuator in the override position. [Figure 18A] FIG. 10 is a perspective view of another example of an auxiliary wheel assembly and override assembly, with the auxiliary wheels in a deployed position. [Figure 18B] FIG. 18B is a perspective view of the auxiliary wheel assembly and override assembly of FIG. 18A, with the auxiliary wheel in an intermediate position. [Figure 18C] FIG. 18B is a perspective view of the auxiliary wheel assembly and override assembly of FIG. 18A, with the auxiliary wheel in a stowed position. [Figure 19A] FIG. 18B is a side view of the auxiliary wheel assembly and override assembly of FIG. 18A shown against a floor surface. [Figure 19B] FIG. 18C is a side view of the auxiliary wheel assembly and override assembly of FIG. 18B shown against a floor surface. [Figure 19C] FIG. 18D is a side view of the auxiliary wheel assembly and override assembly of FIG. 18C shown against a floor surface. [Figure 20A] FIG. 18B is another perspective view of the auxiliary wheel assembly and override assembly of FIG. 18A. [Figure 20B] FIG. 20B is a development view of FIG. 20A. [Figure 20C] FIG. 10 is a bottom perspective view of an auxiliary wheel assembly and an override assembly including a biasing member. [Figure 21] FIG. 1 is a perspective view of one example of an override assembly. [Figure 22A] FIG. 10 is a front view of the auxiliary wheel assembly and override assembly with the auxiliary wheel in an extended position and moving toward a stowed position due to operation of the override assembly. [Figure 22B] FIG. 10 is a front view of the auxiliary wheel assembly and override assembly with the auxiliary wheel in an intermediate state and moving toward a stowed state due to operation of the override assembly. [Figure 22C] FIG. 10 is a front view of the auxiliary wheel assembly and override assembly, where the auxiliary wheel reaches a stowed position due to operation of the override assembly. [Figure 23A] FIG. 22B is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 22A showing the override assembly moving the cam driver to move the auxiliary wheels from the deployed position toward the stowed position. [Figure 23B] FIG. 22C is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 22B showing the override assembly continuing to move the cam driver to move the auxiliary wheels from the deployed state toward the stowed state. [Figure 23C] FIG. 22D is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 22C showing the override assembly continuing to move the cam driver to move the auxiliary wheels from the deployed state toward the stowed state. [Figure 24A] FIG. 10 is a front view of the auxiliary wheel assembly and override assembly, with the auxiliary wheels in an extended state and moving toward a stowed state due to operation of the actuator. [Figure 24B] FIG. 10 is a front view of the auxiliary wheel assembly and override assembly, with the auxiliary wheel in an intermediate state and moving toward the stowed state due to operation of the actuator. [Figure 24C] FIG. 10 is a front view of the auxiliary wheel assembly and override assembly, where the auxiliary wheels reach a stowed position due to operation of the actuator. [Figure 25A]24B is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 24A showing an actuator that moves the cam driver to move the auxiliary wheels from the deployed state toward the stowed state. [Figure 25B] FIG. 24C is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 24B showing the actuator continuing to move the cam driver to move the auxiliary wheels from the deployed state toward the stowed state. [Figure 25C] FIG. 24D is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 24C showing the actuator continuing to move the cam driver to move the auxiliary wheels from the deployed state toward the stowed state. [Figure 26A] FIG. 10 is a front view of the auxiliary wheel assembly and override assembly, where the auxiliary wheel reaches a deployed state due to operation of the actuator. [Figure 26B] FIG. 10 is a front view of the auxiliary wheel assembly and override assembly with the auxiliary wheel in an intermediate state and moving toward the deployed state due to operation of the actuator. [Figure 26C] FIG. 10 is a front view of the auxiliary wheel assembly and override assembly with the auxiliary wheels in a stowed position and moving toward a deployed position due to actuation of the actuator. [Figure 27A] FIG. 26B is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 26A showing an actuator that moves the cam driver to move the auxiliary wheels from the stowed position toward the deployed position. [Figure 27B] 26C is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 26B showing the actuator continuing to move the cam driver to move the auxiliary wheels from the stowed position toward the deployed position. [Figure 27C] FIG. 26D is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 26C showing the actuator continuing to move the cam driver to move the auxiliary wheels from the stowed position toward the deployed position. [Figure 28]FIG. 10 is a partial perspective view of a portion of a patient transport device showing versions of a brake input device. [Figure 29A] FIG. 29 is a front view of a portion of the brake input device of FIG. 28, with the pedal shown positioned in a horizontal orientation and coupled to the linkage in a neutral position. [Figure 29B] 29B is another front view of a portion of the brake input device of FIG. 29A, with the pedal shown rotated in a first direction to move the linkage. FIG. [Figure 29C] 29C is another front view of a portion of the brake input device of FIG. 29B, shown with the pedal rotatably biased in a second direction to return to a horizontal orientation but without moving the linkage. FIG. [Figure 29D] 29D is another front view of the portion of the brake input device of FIG. 29C shown with the pedal further rotated in a second direction, moving the linkage back to the neutral state. FIG. [Figure 29E] 29E is another front view of a portion of the brake input device of FIG. 29D, with the pedal rotatably biased in a first direction to return to a horizontal orientation and the linkage remaining in a neutral state. [Figure 30A] FIG. 10 is a perspective view of yet another example auxiliary wheel assembly and override assembly, with the auxiliary wheels in a deployed position. [Figure 30B] FIG. 30B is a perspective view of the auxiliary wheel assembly and override assembly of FIG. 30A, with the auxiliary wheel in a stowed position. [Figure 31A] FIG. 30B is a side view of the auxiliary wheel assembly and override assembly of FIG. 30A shown against a floor surface. [Figure 31B] FIG. 30C is a side view of the auxiliary wheel assembly and override assembly of FIG. 30B shown against a floor surface. [Figure 32] FIG. 31C is an exploded view of the auxiliary wheel assembly and override assembly of FIGS. 30A-31B. [Figure 33] FIG. 10 is a perspective view of one configuration of a cam assembly of the override assembly. [Figure 34] FIG. 10 is a perspective view of an auxiliary wheel assembly and an override assembly with some components hidden to reveal the cam assembly. [Figure 35] FIG. 10 is a top view of the auxiliary wheel assembly and override assembly, including a first section line KK through the cam driver and a second section line LL through the roller arm. [Figure 36] FIG. 10 is a partial cross-sectional view of the auxiliary wheel assembly and override assembly taken along line LL to reveal one configuration of the roller arm. [Figure 37] FIG. 10 is a partial cross-sectional view of the auxiliary wheel assembly and override assembly taken along line LL to reveal an alternative configuration of the roller arm. [Figure 38A] FIG. 10 is a partial perspective view of the auxiliary wheel assembly and override assembly showing the first pedal in a first pedal steering position and the linkage in a steering state. [Figure 38B] FIG. 10 is a partial perspective view of the auxiliary wheel assembly and override assembly showing the first pedal in a first pedal neutral position and the linkage in a neutral state. [Figure 38C] FIG. 10 is a partial perspective view of the auxiliary wheel assembly and override assembly showing the first pedal in a first pedal braking position and the linkage in a braking state. [Figure 39A] FIG. 38B is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 38A taken along line KK. [Figure 39B] FIG. 38C is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 38B taken along line KK. [Figure 39C] FIG. 38D is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 38C taken along line KK. [Figure 40A] FIG. 38B is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 38A taken along line LL. [Figure 40B] FIG. 38C is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 38B taken along line LL. [Figure 40C] FIG. 38D is a partial cross-sectional view of the auxiliary wheel assembly and override assembly of FIG. 38C taken along line LL. [Figure 41] FIG. 1 is a partial perspective view of a brake input device including a first pedal and a second pedal assembly. [Figure 42] FIG. 2 is a partial cross-sectional view of a second pedal assembly. [Figure 43] FIG. 10 is an exploded view of the second pedal assembly. [Figure 44A] FIG. 10 is a partial perspective view of the auxiliary wheel assembly and override assembly showing the second pedal assembly with the linkage in a braking state. [Figure 44B] FIG. 10 is a partial perspective view of the auxiliary wheel assembly and override assembly showing movement of the second pedal assembly in response to user engagement. [Figure 44C] FIG. 10 is a partial perspective view of the auxiliary wheel assembly and override assembly illustrating movement of the second pedal assembly in response to further user engagement to move the linkage of the steering system to a neutral condition. [Figure 44D] FIG. 10 is a partial perspective view of the auxiliary wheel assembly and override assembly showing movement of the second pedal assembly via the second pedal bias member. [Figure 45] FIG. 44C is a partial perspective view of a second pedal assembly moving in response to user engagement shown in FIG. 44B. [Figure 46] FIG. 44D is a partial perspective view of a second pedal assembly moving in response to user engagement shown in FIG. 44C. [Figure 47] FIG. 44D is a cross-sectional view of the auxiliary wheel assembly and override assembly taken along line KK illustrating movement of the cam driver in response to user engagement shown in FIG. 44C. [Figure 48]FIG. 44D is a cross-sectional view of the auxiliary wheel assembly and override assembly taken along line KK illustrating movement of the cam assembly toward the cam intermediate position in response to user engagement shown in FIG. 44C. [Figure 49A] FIG. 10 is a cross-sectional view of the auxiliary wheel assembly and override assembly taken along line KK showing the actuator drive member. [Figure 49B] FIG. 10 is a cross-sectional view of the auxiliary wheel assembly and override assembly taken along line KK showing the actuator drive member moving in response to actuation of the actuator to move the cam assembly to a cam-down position. [Figure 49C] FIG. 10 is a cross-sectional view of the auxiliary wheel assembly and override assembly taken along line KK showing the actuator drive member moving in response to actuation of the actuator to move the cam assembly to a cam raised position. [Figure 50A] FIG. 10 is a cross-sectional view of the auxiliary wheel assembly and override assembly taken along line LL, showing the cam assembly in the cam intermediate position. [Figure 50B] FIG. 10 is a cross-sectional view of the auxiliary wheel assembly and override assembly taken along line LL showing the cam assembly moving to a cam down position in response to actuation of the actuator. [Figure 50C] FIG. 10 is a cross-sectional view of the auxiliary wheel assembly and override assembly taken along line LL showing the cam assembly moving to a cam raised position in response to actuation of the actuator. DETAILED DESCRIPTION OF THE INVENTION

[0009] Referring to Figure 1, there is shown a patient carrier 30 for supporting a patient in a medical setting. The patient carrier 30 shown in Figure 1 is a hospital bed. However, in other versions, the patient carrier 30 can be a stretcher, cot, wheelchair, transport chair, or similar device utilized in patient care.

[0010] Support structure 32 provides support for the patient. Support structure 32 shown in FIG. 1 includes a base 34 and a support structure 36. Base 34 includes a base frame 35. In FIG. 1, support structure 36 is spaced above base frame 35. Support structure 32 also includes a patient support deck 38 disposed on support structure 36. Patient support deck 38 includes several sections, some of which are capable of articulating (e.g., pivoting) relative to support structure 36, such as a back (supine) section 41, a seat section 43, a leg section 45, and a foot section 47. Patient support deck 38 provides a patient support surface 42 upon which the patient is supported.

[0011] During use, a mattress (not shown) is disposed on the patient support deck 38. The mattress comprises a secondary patient support surface upon which the patient is supported. The base 34, support structure 36, patient support deck 38, and patient support surface 42 each have head and foot ends that correspond to the designated placement of the patient's head and feet on the patient transport device 30. The base 34 includes a longitudinal axis L1 along its length from the head end to the foot end. The structure of the support structure 32 may employ any known or conventional design and is not limited to that specifically illustrated above. Additionally, in certain versions, the mattress may be omitted so that the patient rests directly on the patient support surface 42.

[0012] Patient barriers, such as side rails 44, 46, 48, and 50, are coupled to the support structure 36 and / or the patient support deck 38 and are thereby supported by the base 34. The first side rail 44 is positioned at the right head end. The second side rail 46 is positioned at the right foot end. The third side rail 48 is positioned at the left head end. The fourth side rail 50 is positioned at the left foot end. In the version shown, the head-end side rails 44, 48 are attached to the back section 41 for movement therewith. The foot-end side rails 46, 50 are attached to the support structure 36 for movement therewith. If the patient transport apparatus 30 is a stretcher or cot, there may be fewer side rails. The side rails 44, 46, 48, 50 are movable relative to the back section 41 / support structure 36 between a raised position that blocks access into and out of the patient transport apparatus 30, one or more intermediate positions, and a lowered position that does not obstruct such access. In the version shown, the side rails 44, 46, 48, 50 are connected to the back section 41 and / or support structure 36 by pivoting support arms to form a four-bar linkage. Such side rails, and the manner in which they can be raised and lowered, are shown and described in U.S. Patent Application Publication No. 2017 / 0172829, filed December 15, 2016, entitled "Powered Side Rail For A Patient Support Apparatus," which is incorporated herein by reference in its entirety.

[0013] A headboard 52 and a footboard 54 are coupled to the support structure 36. The headboard 52 and footboard 54 may be coupled anywhere on the patient transport apparatus 30, such as to the support structure 36 or the base 34. In yet other versions, the patient transport apparatus 30 does not include the headboard 52 and / or the footboard 54.

[0014] Caregiver interfaces 56, such as handles, are shown integrated into the headboard 52, footboard 54, and siderails 44, 46, 48, 50 to facilitate movement of the patient transport apparatus 30 across a floor surface. Additional caregiver interfaces 56 may be integrated into other components of the patient transport apparatus 30. The caregiver interfaces 56 can be grasped by a caregiver to manipulate and move the patient transport apparatus 30, to move the siderails 44, 46, 48, 50, etc.

[0015] Other forms of the caregiver interface 56 are also contemplated. The caregiver interface can include one or more handles coupled to the support structure 36. The caregiver interface can simply be a surface on the patient transport apparatus 30 where the caregiver logically applies a force to cause movement of the patient transport apparatus 30 in one or more directions, also referred to as a push position. This can include one or more surfaces on the support structure 36 or base 34. This can also include one or more surfaces on or adjacent to the headboard 52, footboard 54, and / or siderails 44, 46, 48, 50. In other versions, the caregiver interface can include separate handles for each hand of the caregiver. For example, the caregiver interface can include two handles.

[0016] A mobility device is coupled to the base 34 to facilitate transport over the floor surface FS. The mobility device includes a plurality of wheels 58. The wheels 58 are located in each of the four quadrants of the base 34 adjacent the corners of the base 34. In the version shown, the wheels 58 are caster wheels that can rotate and swivel relative to the support structure 32 during transport. Each of the wheels 58 forms part of a caster assembly 60. Each caster assembly 60 is attached to the base 34 and includes a brake 62 for braking the wheel 58 (one example of which is shown in FIGS. 5A-5B). It should be understood that various configurations of the caster assembly 60 are contemplated. Additionally, in some versions, the wheels 58 are not caster wheels, but may be non-steerable, steerable, non-powered, powered, or a combination thereof. Additional wheels are also contemplated. For example, the patient transport device 30 may include four non-powered, non-steerable wheels along with one or more powered wheels.

[0017] 2-4, the patient transport apparatus 30 includes a braking system 64 for allowing a user, such as a caregiver, to selectively engage or disengage brakes 62 associated with the wheels 58. For purposes of illustration, the patient transport apparatus 30 is shown in FIGS. 2-4 with the support structure 36 and patient support deck 38 removed. In the version shown, each of the wheels 58 has an associated brake 62; however, it should be understood that in some versions, fewer than all of the wheels 58 may have an associated brake 62; for example, only one, two, or three of the four wheels 58 may have an associated brake 62. In some versions, the braking system 64 may include multiple brakes 62 (e.g., two, three, four, etc.) configured to brake the wheels 58.

[0018] Braking system 64 includes a linkage 66 operably coupled to brake 62 and a brake input device 68 coupled to linkage 66 in communication with linkage 66 and configured for user engagement to alter operation of brake system 64 between a braked state B and a released state R. In some versions, as described in further detail below, braking system 64 may further include an electric brake assembly 70 also coupled to linkage 66. Linkage 66 is configured to move in response to actuation via brake input device 68 or electric brake assembly 70 to operate brake 62, as described further below.

[0019] As shown in FIG. 4 , the linkage 66 can include a pair of first links 72. In some versions, each of the first links 72 includes an elongated shaft having a hexagonal cross-sectional shape. The first links 72 may also be referred to as hexagonal shafts. In some configurations, the first links 72 extend longitudinally from the head end to the foot end of the patient transport apparatus 30, generally parallel to the longitudinal axis L1. The first links 72 are rotatably supported by the base 34 for rotation about their axes. For example, the first links 72 can be rotatably supported in a caster housing CH or other bracket of the base 34 via a bushing B, bearing, or the like (caster housing CH shown in phantom in FIG. 4 ).

[0020] The linkage 66 may further include a pair of laterally disposed second links 74 at each of the head and foot ends. In some versions, the second links 74 include gear-driven racks, as described further below. The second links 74 are supported by the base 34 for sliding laterally relative to the base 34. Each of the second links 74 is operatively coupled to both of the first links 72 such that movement of either of the second links 74 results in corresponding movement of both of the first links 72 and movement of the other of the second links 74. In other words, the first links 72 and the second links 74 are operatively interconnected such that movement of any one of the links 72, 74 results in movement of the other link 72, 74. For example, movement of one of the second links 74 via the brake input device 68 or the electric brake assembly 70 acts to slide that second link 74, thereby rotating both of the first links 72 and actuating the brake 62.

[0021] In the version shown, the linkage 66 is configured and operable to place the braking system 64 in a braking state B (shown in FIG. 5A ), in which each brake 62 acts to brake the movement of the corresponding wheel 58, and in a released state R (shown in FIG. 5B ), in which each brake 62 is released from braking the wheel 58.

[0022] As shown in FIGS. 5A and 5B , in some versions, each caster assembly 60 includes a plurality of teeth 76 defined along the inner surface of the wheel 58. An eccentric member 78 is coupled to one of the first links 72 and rotates therewith about its axis A. The eccentric member 78 (also referred to as a cam) includes an actuation protrusion 80 that acts against a switching head 82. The switching head 82 is coupled to a vertically movable switching pin 84. A compression spring 86 is attached to the switching pin 84 to bias the switching pin 84 vertically upward toward the eccentric member 78. The brake 62 is coupled to the switching pin 84 and includes a plurality of braking teeth 88 positioned to engage the teeth 76 defined along the inner surface of the wheel 58. In operation, as the first link 72 rotates about axis A via actuation by the brake input device 68 or the electric brake assembly 70, the eccentric member 78 rotates to move the actuation projection 80 along the contoured surface of the switching head 82, moving the brake 62 between a braking state B (FIG. 5A) in which the brake teeth 88 engage the teeth 76 defined along the inner surface of the wheel 58, and a released state R (FIG. 5B) in which the brake teeth 88 are spaced a distance from the teeth 76 defined along the inner surface of the wheel 58.

[0023] 30A-50C, first links 72 are disposed near the head and foot ends of patient transport device 30 and extend laterally, generally transversely, relative to longitudinal axis L1, where links 72 can be connected for simultaneous rotation via override member 372 and timing link 578 (discussed in further detail below).

[0024] In the version of the patient transport apparatus 30 shown, each of a pair of first links 72 extends between two caster assemblies 60 and operates the brakes 62 of the two caster assemblies 60. In other words, rotation of one of the first links 72 operates two brakes of two caster assemblies 60, and rotation of the other of the first links 72 operates two brakes of two other caster assemblies 60, thereby braking all four caster assemblies 60 substantially simultaneously (substantially simultaneously due to any tilt or tolerance in the linkages 66).

[0025] Other suitable caster assemblies having brakes that operate via hexagonal shafts or other suitable actuating members may also be used. For example, the caster assemblies and associated brakes may be similar to those disclosed in U.S. Patent No. 8,789,662, entitled "Wheeled Carriage With Brake Lock System," which is incorporated herein by reference. Additionally, the brakes may be external brakes or other forms of brakes that operate via linkages but may not be part of the caster assembly.

[0026] In some configurations, when the braking system 64 is in the release state R, the linkage 66 may be further operable between a neutral state N and a steering state S. In the neutral state N, each brake 62 is released from braking the wheels 58, and at least one auxiliary wheel 302 (described in further detail below) may be spaced from the floor surface FS. In the steering state S, each brake 62 remains released from braking the wheels 58, and at least one auxiliary wheel 302 is moved to a deployed position 302D (described in further detail below).

[0027] 6A-6C, brake input devices 68 (one at each of the head and foot ends) are coupled to linkages 66 that are manually moved to place brake system 64 in a braked state B or a released state R. In some configurations, brake input device 68 may be further configured to move linkage 66 between a neutral state N and a steering state S. With reference to FIG. 6A, brake input device 68 is operable by a caregiver to place linkage 66 in the neutral state N and brake system 64 in the released state R so that each brake 62 is released from braking wheels 58. With reference to FIG. 6B, brake input device 68 may be operable by a caregiver to place linkage 66 and brake system 64 in the braked state B so that each brake 62 brakes wheels 58. Referring to FIG. 6C, the brake input device 68 can be operated by a caregiver to place the linkage in the steering state S, maintain the braking system 64 in the release state R, and release the brakes 62 from the wheels 58.

[0028] The brake input device 68 shown in Figures 6A to 6C moves the second link 74 in a first direction D1, placing the brake system 64 in a braked state B (see the transition from Figure 6A to Figure 6B), and moves the second link 74 in a second direction D2 opposite to the first direction D1, placing the link mechanism 66 in a neutral state N and placing the brake system 64 in a released state R from the braked state B (see the transition from Figure 6B to Figure 6A). Additionally, in some configurations, such as those shown in FIGS. 6B-6C , the brake input device 68 moves the second link 74 in a second direction D2 to place the linkage 66 in the steering state S while maintaining the braking system 64 in the release state R (see the transition from FIGS. 6A to 6C ), and moves the second link 74 in a first direction D1 to place the linkage 66 in the neutral state N and place the braking system 64 in the release state R from the braking state B (see the transition from FIG. 6C to FIG. 6A ). As described in further detail below, in some configurations, the brake input device 68 is not operable to move the linkage 66 from the neutral state N to the steering state S, and only the electric brake assembly 70 is configured to move the linkage 66 from the neutral state N to the steering state S. Note that various components of the braking system 64 have been removed in FIGS. 6A-6C for purposes of illustrating the movement of the linkage 66 between the various states.

[0029] The electric braking assembly 70 is also coupled to the linkage 66 and includes a motor 120 and a drive shaft 122 configured to move the linkage 66 to place the braking system 64 in a braking state B, the braking system 64 in a released state R / the linkage 66 in a neutral state N, and / or the linkage 66 in a steering state S. The electric braking assembly 70 includes a drive member 106 configured to be moved by the drive shaft 122 to move the second link 74 in a first direction D1 and to move the second link 74 in a second direction D2. The motor 120 and the drive shaft 122 form part of a brake actuator assembly 108. The brake actuator assembly 108 is coupled to the drive member 106 to provide torque to move the second link 74 in the first direction D1 and to move the second link 74 in the second direction D2. Additional structural details and one example of the operation of the braking system 64 are described in U.S. Patent Application Publication No. 2019 / 0192364, entitled "Patient Transport Apparatus With Electro-Mechanical Braking System," and U.S. Patent Application No. 17 / 825,536, entitled "Patient Transport Apparatus With Electro-Mechanical Braking Input Hold Circuit," both of which are incorporated herein by reference.

[0030] Referring to FIG. 7 , the illustrated patient transport apparatus 30 includes a control system 200 for controlling, among other things, the electric brake assembly 70. The control system 200 includes a controller 202 having one or more microprocessors, microcontrollers, field programmable gate arrays, systems-on-chips, discrete circuitry, and / or other suitable hardware, software, or firmware capable of performing the functions described herein. The controller 202 may be carried onboard the patient transport apparatus 30 or may be located remotely. In some versions, the controller 202 is mounted to the base 34. In other versions, the controller 202 is mounted to the footboard 54. Power to the electric brake assembly 70 and / or the controller 202 may be provided by a battery power source and / or an external power source. The controller 202 is coupled to the electric brake assembly 70 in a manner that enables the controller 202 to control the brake actuator assembly 108 (connections are shown schematically in FIG. 7 ). The controller 202 may communicate with the brake actuator assembly 108 via a wired or wireless connection to perform one or more of the desired functions.

[0031] The control system 200 may include a user interface with one or more user input devices 232 that are operated by a caregiver and send corresponding input signals to the controller 202. The controller 202 controls the operation of the brake actuator assembly 108 based on the input signals. The user input devices 232 may include any device that can be actuated by a caregiver. The user input devices 232 may be configured to be actuated in a variety of different ways, including, but not limited to, mechanical actuation (hand, foot, finger, etc.), hands-free actuation (voice, foot, etc.), etc.

[0032] The user input devices 232 may also include gesture detection devices for monitoring the movement of the caregiver's hands, feet, or other body parts (e.g., via a camera), microphones for receiving voice-activated commands, foot pedals, and sensors (e.g., infrared sensors, ultrasonic sensors, etc., such as a light bar or light beam that detects the caregiver's body parts). Additionally, the user input devices 232 may include buttons / pedals, which may be physical buttons / pedals or virtually implemented buttons / pedals, such as through optical projection or on a touchscreen. The buttons / pedals may also be mechanically connected buttons / pedals or drive-by-wire type buttons / pedals in which a force applied by the caregiver activates a sensor, such as a switch or potentiometer. It should be understood that any combination of user input devices 232 may be utilized. The user input devices 232 may be located on one of the siderails 44, 46, 48, 50, the headboard 52, the footboard 54, or other suitable locations. The user input device 232 may also be located on a portable electronic device (e.g., an iWatch®, an iPhone®, an iPad®, or a similar electronic device).

[0033] In the illustrated version, the controller 202 includes a processor 234 and a memory device 236. The processor 234 includes any suitable programmable circuitry. Any suitable programmable circuitry may include one or more system and microcontrollers, microprocessors, reduced instruction set circuits (RISC), application specific integrated circuits (ASIC), programmable logic circuits (PLC), field programmable gate arrays (FPGA), and any other circuitry capable of performing the functions described herein. The above examples are illustrative only and are thus not intended to limit in any way the definition and / or meaning of the term “processor.” The memory device 236 includes computer-readable media, such as, but not limited to, random access memory (RAM), flash memory, hard disk drives, solid-state drives, diskettes, flash drives, compact discs, digital video discs, and / or any other suitable device that enables the processor 234 to store, retrieve, and / or execute instructions and / or data.

[0034] In the exemplary version, the controller 202 includes a motor control module 238 coupled to the brake actuator assembly 108 and configured to control operation of the brake actuator assembly 108. The motor control module 238 is configured to execute programming code in response to input received by a caregiver via a user interface and to operate the brake actuator assembly 108 based on the user input.

[0035] The controller 202 also includes a user input module 242 configured to receive input signals from the user input device 232 and / or generate and display images for display on one or more display devices of the user interface. For example, the user input module 242 can generate image data that is stored in the memory device 236, transmit the image data to the user interface, and enable one or more display devices to display the images to the caregiver. The user input module 242 also transmits signals to the status indicators 230, causing the status indicators 230 to operate to indicate the detected condition.

[0036] During operation of the electric braking assembly 70, when a caregiver desires to electronically engage or disengage the braking system 64, the caregiver actuates one or more of the user input devices 232 (as opposed to manually doing so via the brake input device 68). For example, if the caregiver desires to brake the wheels 58 and stop movement of the patient transport apparatus 30, the caregiver actuates the appropriate user input device 232. Upon actuation, the controller 202 sends an output signal to the brake actuator assembly 108, causing the brake actuator assembly 108 to move accordingly. Similarly, one or more of the user input devices 232 can be used to disengage the braking system 64 or place the linkage 66 in the steering state S.

[0037] Additional details and operation of control system 200 are described in U.S. patent application Ser. No. 17 / 825,536, entitled "Patient Transport Apparatus With Electro-Mechanical Braking Input Hold Circuit," which is incorporated herein by reference.

[0038] As shown in FIGS. 1 and 2, the patient transport apparatus 30 further includes an auxiliary wheel assembly 300 coupled to the support structure 36. Referring to FIGS. 8A-8C, the auxiliary wheel assembly 300 includes at least one auxiliary wheel 302 and an actuator 304 configured to move the at least one auxiliary wheel 302 between a plurality of auxiliary support positions, including a stowed position 302S and a deployed position 302D. FIG. 8A schematically illustrates the patient transport apparatus 30 including the auxiliary wheel assembly 300, where the at least one auxiliary wheel 302 is in the stowed position 302S such that the one or more auxiliary wheels 302 are spaced apart from the floor surface FS. FIG. 8B schematically illustrates the patient transport apparatus 30 including the auxiliary wheel assembly 300, where the at least one auxiliary wheel 302 is in the deployed position 302D such that the one or more auxiliary wheels 302 engage the floor surface FS to at least partially support movement of the patient transport apparatus 30 over the floor surface FS. In some configurations, the at least one auxiliary wheel 302 can be positioned as shown in FIG. 8B in response to the linkage 66 being moved to the neutral state N. FIG. 8C schematically illustrates a patient transport apparatus 30 including an auxiliary wheel assembly 300, in which the at least one auxiliary wheel 302 is positioned between the caster assemblies 60 and contacts the floor surface FS in the deployed position 300D, thereby shortening the wheelbase of the patient transport apparatus 30 by elevating two of the caster assemblies 60 off the floor surface. Additionally, in some configurations, the at least one auxiliary wheel 302 does not swivel. Thus, when the at least one auxiliary wheel 302 is deployed as shown in FIG. 8C, the at least one auxiliary wheel 302 guides the movement of the patient transport apparatus by restricting lateral movement along the floor surface FS. In some configurations, the at least one auxiliary wheel 302 can be positioned as shown in FIG. 8C in response to the linkage 66 being moved to the steering state S.

[0039] 8A-8C , in some versions, the auxiliary wheel assembly 300 further includes an axle assembly 306. The axle assembly 306 (shown schematically in FIGS. 8A-8C ) is configured to support one or more auxiliary wheels 302 for rotational movement. The axle assembly 306 may be coupled to the base 34 by one or more linkages, actuators, links, etc. for pivotal movement relative to the base 34 to move the one or more auxiliary wheels 302 between a plurality of auxiliary support positions, including a deployed position 302D and a stowed position 302S. It will be understood that various configurations of the axle assembly 306 are contemplated. Exemplary arrangements of the axle assembly 306 are described below.

[0040] In some configurations, the auxiliary wheel assembly 300 further comprises an auxiliary wheel drive system (not shown) including a motor operably attached to one or more auxiliary wheels 302 and configured to generate torque to rotate the one or more auxiliary wheels 302 and affect movement of the patient transport apparatus 30 over the floor surface FS. Additionally, it is contemplated that the one or more auxiliary wheels 302 may take forms other than traditional wheels, such as, but not limited to, tracks. In some versions, the auxiliary wheel assembly 300 can be similar to those disclosed in U.S. Patent Application Publication No. 2019 / 0201255, entitled "Patient Transport Apparatus With Controlled Auxiliary Wheel Deployment," and / or U.S. Patent Application Publication No. 2019 / 0201256, entitled "Patient Transport Apparatus With Controlled Auxiliary Wheel Speed," the disclosures of each of which are incorporated herein by reference in their entirety.

[0041] 9(A) and (B), in some versions, the patient transport apparatus 30 may further include a spring cartridge 308 disposed between the support structure 36 and the one or more auxiliary wheels 302 to bias the one or more auxiliary wheels 302 toward the deployed position 302D and enable the one or more auxiliary wheels 302 to deflect in response to engagement with an uneven floor surface FS. Thus, in some configurations, the deployed position 302D may be characterized as a plurality of deployed positions 302D, in which the one or more auxiliary wheels 302 are configured to deflect to maintain contact with the uneven floor surface FS. Any suitable arrangement of the spring cartridge 308 between the support structure 36 and the one or more auxiliary wheels 302 is contemplated. Exemplary arrangements of the spring cartridge 308 are described below.

[0042] The patient transport apparatus 30 includes an override assembly 310 (shown schematically in FIGS. 10A and 10B) coupled to the linkage 66 of the braking system 64 and the auxiliary wheel assembly 300. In one example, the override assembly 310 can be coupled to the link 72 of the braking system 64. Thus, the override assembly 310 is configured to move in response to movement of the linkage 66. The override assembly 310 is configured to move one or more auxiliary wheels 302 away from the deployed position 302D (shown schematically in FIG. 10A) toward the stowed position 302S in response to movement of the braking system 64 from the released state R toward the braked state B (shown schematically in FIG. 10B).

[0043] As will become apparent from the subsequent description below, the override assembly 310 is configured to move in response to movement of the linkage 66 of the braking system 64 to prevent movement of the base 34 along the floor surface FS and to at least partially disengage one or more auxiliary wheels 302 from the floor surface FS in Braking State B. In other words, as the braking system 64 moves toward Braking State B, the override assembly 310 is configured to lift one or more auxiliary wheels 302 to at least partially disengage the one or more auxiliary wheels 302 from the floor surface FS. Thus, the weight of the patient transport device 30 is transferred away from the auxiliary wheels 302 and onto the wheels 58, causing the brakes 62 of the wheels 58 to prevent movement of the base 34 along the floor surface FS and preventing any lifting of the wheels 58 via the auxiliary wheels 302 (particularly when the linkage 66 is in Steered State S). It will be appreciated that with this configuration, the powered actuator 304 is not required to facilitate moving one or more auxiliary wheels 302 out of engagement with the floor surface FS away from the deployed position 302D in that manual actuation of the brake input device 68 can simultaneously disengage the one or more auxiliary wheels 302 from the floor surface FS and position the wheels 58 in braking condition B without battery power.

[0044] It will be appreciated that the override assembly 310 can move one or more auxiliary wheels 302 without actuation of the actuator 304. For example, comparing FIGS. 8A and 8B with FIGS. 10A and 10B, in FIGS. 8A and 8B, the actuator 304 decreases in length to move one or more auxiliary wheels 302 from the deployed position 302D to the stowed position 302S. Meanwhile, in the illustrations of FIGS. 10A and 10B, the actuator 304 maintains the same length while the override assembly 310 moves one or more auxiliary wheels 302 from the deployed position 302D toward the stowed position 302S. Furthermore, it will be appreciated that the override assembly 310 can be configured to move one or more auxiliary wheels 302 away from the deployed position 302D toward the stowed position 302S in response to movement of the braking system 64 from the released state R toward the braked state B in a number of different manners, examples of which are described below.

[0045] 11A-17C show a portion of a patient transport apparatus 30 including versions of an auxiliary wheel assembly 300 and an override assembly 310. Referring first to FIG. 11A, in some versions, the auxiliary wheel assembly 300 includes an auxiliary frame 312 coupled to the base 34, with one or more auxiliary wheels 302 and actuators 304 operably attached to the auxiliary frame 312. The auxiliary frame 312 can include a first auxiliary rail 314 extending longitudinally along the patient transport apparatus 30 (e.g., along the longitudinal axis L1) and coupled to a first base rail 34A of the base 34, and a second auxiliary rail 316 extending longitudinally along the patient transport apparatus 30 and coupled to a second base rail 34B of the base 34. The auxiliary frame 312 may further include a first cross member 318 extending between the first and second auxiliary rails 314, 316 at a first end 320 of the auxiliary wheel assembly 300, and a second cross member 322 extending between the first and second auxiliary rails 314, 316 at a second end 324 of the auxiliary wheel assembly 300. Other configurations for supporting the one or more auxiliary wheels 302 and actuators 304 are contemplated, including, without limitation, a cross member extending directly between the first and second base rails 34A, 34B.

[0046] 11C , the actuator 304 is coupled to the axle assembly 306 at a first actuator end 304A and operably attached (e.g., via the override assembly 310) to the second cross-member 322 (or another portion of the auxiliary frame 213) at a second actuator end 304B. The actuator 304 is thus configured to move the axle assembly 306, and thus move the one or more auxiliary wheels 302, between the deployed position 302D and the stowed position 302S. In the configuration shown in FIGS. 11A-17C , the axle assembly 306 is operably attached to the first cross-member 318 for pivotal movement relative to the first cross-member 318 to move the one or more auxiliary wheels 302 between a plurality of auxiliary support positions, including the deployed position 302D and the stowed position 302S.

[0047] 12 and 13 , axle assembly 306 may further include a first axle subassembly 326 and a second axle subassembly 328. In some versions, first axle subassembly 326 may be operably attached to first cross-member 318 for pivotal movement relative to first cross-member 318. For example, first axle subassembly 326 may include a first axle member 330 extending between a first end 330A and a second end 330B. First axle member 330 may also include at least one axle shaft 331 for rotatably supporting at least one auxiliary wheel 302. The first axle subassembly 326 may further include a first pair of swing arms 332 coupled to and extending between the first axle member 330 and the first cross-member 318 to facilitate pivotal movement of the first axle member 330 relative to the first cross-member 318. It should be understood that the structure of the first axle subassembly 326 shown in Figures 12 and 13 is intended to be a non-limiting example, and that any structure configured to support one or more auxiliary wheels 302, move relative to the auxiliary frame 312, and move the one or more auxiliary wheels 302 between a plurality of auxiliary support positions, including a deployed position 302D and a stowed position 302S, is contemplated.

[0048] The second axle subassembly 328 may be operably mounted to the first cross-member 318 of the sub-frame 213 for pivotal movement relative to the first cross-member 318. It will be appreciated that the second axle subassembly 328 may be configured to pivot relative to the first cross-member 318 of the sub-frame 312 independently of the first axle subassembly 326. However, as discussed below, the second axle subassembly 328 may be operably mounted to the first axle subassembly 326 (e.g., via a spring cartridge, as described below) to coordinate movement of the second axle subassembly 328 with the first axle subassembly 326. Thus, movement of the second axle subassembly 328 may effect movement of the first axle subassembly 326. In other words, by moving one of the first axle subassembly 326 and the second axle subassembly 328 , the entire axle assembly 306 can be pivoted relative to the sub-frame 312 .

[0049] The second axle subassembly 328 may include a second axle member 334 extending between a first end 334A and a second end 334B. In the version shown, the second axle member 334 is sized to fit between the first pair of swing arms 332 of the first axle subassembly 326. The second axle subassembly 328 may further include a second pair of swing arms 336 coupled to and extending between the second axle member 334 and the first cross-member 318 to facilitate pivotal movement of the second axle member 334 relative to the first cross-member 318. In the version shown, the first actuator end 304A is coupled to the second axle subassembly 328 (more particularly, to the second axle member 334) for moving the axle assembly 306 relative to the auxiliary frame 312 to move the one or more auxiliary wheels 302 between the deployed position 302D and the stowed position 302S. It should be understood that the structure of the first axle subassembly 326 shown in Figures 12 and 13 is intended to be a non-limiting example and that other configurations are contemplated.

[0050] 12 and 13 show an example configuration of an axle assembly 306 coupled to the auxiliary frame 312. In this version, the first cross-member 318 of the auxiliary frame 312 may further include a first pair of brackets 338 extending longitudinally (e.g., along the longitudinal axis L1) from the first end 318A of the first cross-member 318 and a second pair of brackets 340 extending longitudinally from the second end 318B of the first cross-member 318. It should be understood that, as shown in FIG. 13 , one of the first pair of brackets 338 may be integral with the first auxiliary rail 314. Similarly, it should be understood that, as shown in FIG. 13 , one of the second pair of brackets 340 may be integral with the second auxiliary rail 316. The first pair of brackets 338 and the second pair of brackets 340 may each define a coaxial bore 342 that defines a pivot axis 344. In some versions, the first axle subassembly 326 is coupled to the first and second pairs of brackets 338, 340 via one or more pivot shafts 346 disposed within the coaxial bore 342 for pivotal movement of the first axle subassembly 326 about the pivot axis 344. Similarly, the second axle subassembly 328 is coupled to the first and second pairs of brackets 338, 340 via one or more pivot shafts 346 disposed within the coaxial bore 342 for pivotal movement of the second axle subassembly 328 about the pivot axis 344.

[0051] 12 and 13 , a suspension system is shown having a first spring cartridge 348 disposed between the first axle subassembly 326 (more specifically, the first axle member 330) and the first cross-member 318. The first spring cartridge 348 is configured to bias the axle assembly 306 toward the deployed position 302D and to allow the axle assembly 306 to deflect toward the stowed position 302S in response to engagement of one or more auxiliary wheels 302 with an uneven floor surface. In this example, the first spring cartridge 348 extends between a first end 348A and a second end 348B. The first end 348A of the first spring cartridge 348 can be coupled to a third pair of brackets 350 extending longitudinally (e.g., along the longitudinal axis L1) from the first cross-member 318. The second end 348B can be coupled to the first axle subassembly 326 (more specifically, to the first axle member 330) via a pair of first axle brackets 352 extending from the first axle member 330. The first spring cartridge 348 is thus configured to urge the first axle subassembly 326 away from the first cross-member 318 such that the one or more auxiliary wheels 302 are biased toward the deployed position 302D but still capable of deflecting if the one or more auxiliary wheels 302 contact an uneven floor surface FS. One non-limiting example of a suitable first spring cartridge 348 includes a coil-over shock absorber. Other spring cartridge configurations are contemplated.

[0052] The suspension system of the auxiliary wheel assembly 300 may further include at least one second spring cartridge 354 disposed between the second axle subassembly 328 and the first axle subassembly 326. The second spring cartridge 354 is configured to allow the second axle subassembly 328 to deflect relative to the first axle subassembly 326 in response to the one or more auxiliary wheels 302 engaging an uneven floor surface FS. In this example, the at least one second spring cartridge 354 extends between a first end 354A and a second end 354B. The first end 354A may be coupled to the first axle member 330 of the first axle subassembly 326 (e.g., coupled to the first pair of axle brackets 352). The second end 354B may be coupled to the second axle subassembly 328 (e.g., coupled to the second pair of axle brackets 355 extending from the second axle member 334). The second spring cartridge 354 is thus configured to allow the second axle subassembly 328 to deflect relative to the first axle subassembly 326 in response to the one or more auxiliary wheels 302 engaging an uneven floor surface FS. One non-limiting example of a suitable second spring cartridge 354 includes a coil-over shock absorber. Other spring cartridge configurations are contemplated.

[0053] 14A-14C (and also FIGS. 14D-14F) show a series of one or more auxiliary wheels 302 of an auxiliary wheel assembly 300 moving from a deployed position 302D toward a stowed position 302S, at least partially disengaging the one or more auxiliary wheels 302 from the floor surface FS. More specifically, FIGS. 14A-14C depict disengagement via operation of the override assembly 310, while FIGS. 14D-14F depict disengagement via operation of the actuator 304. FIG. 14A shows one or more auxiliary wheels 302 of the auxiliary wheel assembly 300 in the deployed position 302D. FIGS. 16A and 17A, described in more detail below, show the arrangement of the linkage 66 and override assembly 310 corresponding to FIG. 14A, where the braking system 64 is in the released state R such that the brake 62 is disengaged from the wheel 58, and the linkage 66 is in the steered state S such that the linkage assembly 360 is in the extended state SE. FIG. 14B shows one or more auxiliary wheels 302 of the auxiliary wheel assembly 300 in an intermediate position 302I. FIGS. 16B and 17B, described in more detail below, show the arrangement of the linkage 66 and override assembly 310 corresponding to FIG. 14B, where the braking system 64 is in the released state R such that the brakes 62 are released from the wheels 58, and the linkage 66 is in the neutral state N such that the linkage assembly 360 is in the intermediate state SI. FIG. 14C shows one or more auxiliary wheels 302 of the auxiliary wheel assembly 300 in a stowed position 302S. FIGS. 16C and 17C, described in more detail below, show the arrangement of the linkage 66 and override assembly 310 corresponding to FIG. 14C, where the braking system 64 is in the braking state B such that the brakes 62 are braking the wheels 58, and the linkage 66 is in the braking state B such that the linkage assembly 360 is in the folded state SC.It should be understood that in the sequence of Figures 14A-14B, no movement of the actuator 304 occurs, and one or more auxiliary wheels 302 are moved from the deployed position 302D to the stowed position 302S due to the movement of the linkage assembly 360 from the extended state SE toward the folded state SC, which occurs as a result of the linkage 66 moving from the steering state S to the braking state B.

[0054] 15A and 15B , in one configuration, the override assembly 310 includes a carriage 356 extending longitudinally between a first carriage end 356A spaced from the auxiliary frame 312 and a second carriage end 356B coupled to the auxiliary frame 312. For example, the second carriage end 356B can be coupled to the second cross-member 322. The override assembly 310 can further include a trolley 358 coupled to the second actuator end 304B of the actuator 304 and engaging the carriage 356 to guide movement of the second actuator end 304B along the carriage 356. The carriage 356 is configured to guide movement of the trolley 358 to guide the second actuator end 304B between an operating position PO (shown in FIGS. 16A and 17A ) and an override position PR (shown in FIGS. 16C and 17C ). In the operating position PO, the second actuator end 304B is fixed in spaced apart relationship to support the actuator 304 to move the one or more auxiliary wheels 302 between the deployed position 302D and the stowed position 302S at a first distance D1 (shown in FIG. 17A ) from the auxiliary frame 312. In the override position PR, the second actuator end 304D is fixed in spaced apart relationship to move the actuator 304 to at least partially disengage the one or more auxiliary wheels 302 from the floor surface FS at a second distance D2 (shown in FIG. 17C ) that is less than the first distance D1 from the auxiliary frame 312.

[0055] The override assembly 310 may further include an override linkage 360 ​​coupled to and disposed between the auxiliary frame 312 (e.g., the second cross-member 322) and the second actuator end 304B to move the second actuator end 304B between the operating position PO and the override position PR. The override linkage 360 ​​may be configured for movement between the extended state SE (shown in FIGS. 16A and 17A ) and the folded state SC (shown in FIGS. 16C and 17C ). In the extended state SE, the override linkage 360 ​​moves the second actuator end 304B to the operating position PO. In the folded state SC, the override linkage 360 ​​moves the second actuator end 304B to the override position PR.

[0056] 15A and 15B, in some versions, the override linkage 360 ​​can include a first link 362 and a second link 364. The first link 362 can include a first link attachment end 362A coupled to the second actuator end 304B for pivotal movement relative to the second actuator end 304B, and a first link pivot end 362B. The second link 364 can include a second link attachment end 364A coupled to the auxiliary frame 312 (e.g., the second cross-member 322) for pivotal movement relative to the auxiliary frame 312, and a second link pivot end 364B coupled to the first link pivot end 362B for pivotal movement relative to the first link pivot end 362B. The first link pivot end 362B and the second link pivot end 364B may be coupled via a link pivot shaft 366, although other configurations for coupling the first link pivot end 362B and the second link pivot end 364B for pivotal movement are contemplated. The first link attachment end 362A may be coupled to the carriage 356 and / or the second actuator end 304B via a first mounting shaft 368 for pivotal movement relative to the carriage 356 and / or the second actuator end 304B. Similarly, the second link attachment end 364A may be coupled to the auxiliary frame 312 (e.g., the second cross-member 322) via a second mounting shaft 370 for pivotal movement relative to the auxiliary frame 312. Thus, the override linkage 360 ​​is configured to move from the extended state SE to the folded state SC and hinge at the link pivot shaft 366 to move the second actuator end 304B from the operating position PO to the override position PR. Other configurations are contemplated for moving the second actuator end 304B between the operating position PO and the override position PR.

[0057] The override assembly 310 may further include an override member 372 coupled to and extending between the linkage 66 (e.g., the link 72 of the braking system 64) and the override linkage 360, for simultaneously moving the override linkage 360 ​​from the extended state SE to the folded state SC as the braking system 64 moves from the released state R to the braked state B. In one example, as best shown in FIGS. 16A-17C , the link 72 of the braking system 64 may be a hexagonal shaft 72 configured to rotate in response to the braking system 64 moving between the braked state B and the released state R, as described above. The hexagonal shaft 72 may be coupled to the override member 372 such that rotation of the hexagonal shaft 72 is converted into translation of the override member 372, for simultaneously moving the override linkage 360 ​​from the extended state SE to the folded state SC as the braking system 64 moves from the released state R to the braked state B. In one example, the link 72 of the braking system 64 can further include a pivot arm 374 extending from the hexagonal shaft. In this example, the override member 372 is coupled to and extends between the pivot arm 374 of the link 72 and one of the first link pivot end 362B and the second link pivot end 364B to simultaneously move the override linkage 360 ​​from the extended state SE to the folded state SC when the braking system 64 moves from the released state R to the braked state B.

[0058] 16A-17C illustrate a sequence for operating the example override assembly 310 to move one or more auxiliary wheels 302 from the deployed position 302D toward the stowed position 302S, thereby at least partially disengaging the one or more auxiliary wheels 302 from the floor surface FS. FIGS. 16A and 17A show the linkage 66 in the steering state S, resulting in the override linkage being in the extended state SE and the second actuator end 304B being in the operating position PO, whereby the actuator 304 is configured to move the axle assembly 306 to move the one or more auxiliary wheels 302 between the deployed position 302D and the stowed position 302S. FIGS. 16B and 17B show the linkage 66 in the neutral state N, resulting in the override linkage 360 ​​being in the intermediate state SI, which moves the braking system 64 from the released state R toward the braked state B as the hexagonal shaft 72 rotates. The override member 372 translates in response to rotation of the hexagonal shaft 72, moving the override linkage 360 ​​toward the folded state SC. As a result, the override linkage 360 ​​moves the second actuator end 304B along the carriage 356 toward the override position PR. FIGS. 16C and 17C show the linkage 66 in braking state B, with the override linkage 360 ​​in the folded state SC. The override linkage 360 ​​now moves to the folded state SC as the hexagonal shaft 72 continues to rotate to place the braking system 64 in braking state B. The override member 372 moves the override linkage 360 ​​to the folded state SC simultaneously with the hexagonal shaft 72 as the braking system 64 reaches braking state B. As a result, the override linkage 360 ​​moves the second actuator end 304B along the carriage 356 to the override position PR, causing the actuator 304 to move toward the auxiliary frame 312 to raise the axle assembly 306 to at least partially disengage the one or more auxiliary wheels 302 from the floor surface FS.

[0059] 18A-27C show a portion of a patient transport apparatus 30 including another example of an auxiliary wheel assembly 300 and an override assembly 310. Referring to FIGS. 18A-18C, the auxiliary wheel assembly 300 can include an axle assembly 306 for supporting one or more auxiliary wheels 302. In this example, the axle assembly 306 is coupled to the base 34 (e.g., to the first base rail 34A and the second base rail 34B) for pivotal movement relative to the base 34 to move the one or more auxiliary wheels 302 between a plurality of auxiliary support positions, including a deployed position 302D and a stowed position 302S. In this example, the axle assembly 306 includes an axle member 330 including at least one axle shaft 331 for rotatably supporting the at least one auxiliary wheel 302. The axle assembly 306 in this example may further include a pair of swing arms 332 coupled to and extending between the axle member 330 and the base 34 to facilitate pivotal movement of the axle member 330 relative to the base 34.

[0060] 18A-19C show a series of one or more auxiliary wheels 302 of an auxiliary wheel assembly 300 moving from a deployed position 302D toward a stowed position 302S, causing the one or more auxiliary wheels 302 to at least partially disengage from the floor surface FS. FIGS. 18A and 19A show the one or more auxiliary wheels 302 of the auxiliary wheel assembly 300 in the deployed position 302D. FIGS. 18B and 19B show the one or more auxiliary wheels 302 of the auxiliary wheel assembly 300 in an intermediate position 302I. FIGS. 18C and 19C show the one or more auxiliary wheels 302 of the auxiliary wheel assembly 300 in the stowed position 302S.

[0061] 20A-21 , the override assembly 310 of the present example includes a cam member 376 disposed between the base 34 and the axle assembly 306 and operably attached to the axle assembly 306 to move the axle assembly 306 relative to the base 34. For example, the cam member 376 can be rotatably supported by a cam support bracket 378 extending between the first base rail 34A and the second base rail 34B. Additionally, the cam member 376 can contact the axle member 330 to move the axle member 330 relative to the base 34. The cam member 376 can be configured to move between a plurality of cam positions, including a cam-up position CL (shown in FIGS. 22A and 23A ) and a cam-down position CO (shown in FIGS. 22C and 23C ). In the cam-up position CL, the cam member 376 moves one or more auxiliary wheels 302 to the deployed position 302D. In the cam-down position CO, the cam member 376 moves the one or more auxiliary wheels 302 to the stowed position 302S. In some versions, as best shown in FIG. 20C , the auxiliary wheel assembly 300 also includes a biasing member 382 operably attached to the base 34 and the axle assembly 306, where the biasing member 382 is configured to bias the axle assembly 306 against the cam member 376. For example, with continued reference to FIG. 20C , the biasing member 382 is a spring operably attached to one end of the base 34 and to another end of the pivot member 383. In this example, the spring creates tension between the base 34 and the pivot member 383. The pivot member 383 is pivotally attached to the base 34 and the first axle member 330 such that the biasing member 382 biases the pivot member 383 to bias the axle assembly 306 against the cam member 376.

[0062] In some versions, the axle assembly 306 of the auxiliary wheel assembly 300 may include a roller 380 coupled to the axle assembly 306 and disposed between the axle assembly 306 and the cam member 376. The roller 380 may be configured to rotate to abut the cam member 376 and allow the cam member 376 to move between a cam down position CO and a cam up position CL. Additionally, in some versions, the cam member 376 defines a plurality of detents 384. The plurality of detents 384 are configured to engage the roller 380 to retain the cam member 376 in a corresponding cam position. For example, the cam member 376 may define a cam up detent 384A to retain the cam member 376 in the cam up position CL (shown in FIGS. 22A and 23A ), thereby retaining the auxiliary wheel in the deployed position 302D. The cam member may also define a cam down detent 384C for retaining the cam member 376 in the cam down position CO (shown in FIGS. 22C and 23C), thereby retaining the auxiliary wheels in the stowed position 302S. In some versions, the cam member 376 includes a cam intermediate detent 384I disposed between the cam up detent 384A and the cam down detent 384C for retaining the cam member 376 at a cam intermediate position CI between the cam up position CL and the cam down position CO (shown in FIGS. 22B and 23B), thereby retaining the auxiliary wheels at an intermediate position 302I between the auxiliary wheels in the stowed position 302S and the auxiliary wheels in the deployed position 302D.

[0063] 20A-21 , auxiliary wheel assembly 300 can further include a cam driver 386 coupled to cam member 376 for simultaneous rotation therewith. Similar to cam member 376, cam driver 386 can be rotatably supported by cam support bracket 378. For example, both cam member 376 and driver 386 can be coupled to a cam shaft 388 that is rotatably supported by cam support bracket 378. In one example, cam shaft 388 defines key slots (not shown) corresponding to key slots defined by each of cam member 376 and cam driver 386 such that cam member 376 and cam driver 386 can be coupled to cam shaft 388 using a key (not shown) such that cam member 376 and cam driver 386 rotate simultaneously. Additionally, as shown in the configuration of FIGS. 20A-21 , actuator 304 can be a rotary actuator 304 configured to generate torque about actuator axis 390. Furthermore, auxiliary wheel assembly 300 may further include an actuator drive member 392 coupled to actuator 304 for simultaneous rotation therewith about actuator axis 390. In this example, cam driver 386 may define a slot 394 extending between a first slot end 394A and a second slot end 394B. Additionally, actuator drive member 392 may include a protrusion 396 spaced from actuator axis 390 and disposed within slot 394 of cam driver 386. Thus, protrusion 396 is configured to translate within slot 394 of cam driver 386 and abut one of first slot end 394A and second slot end 394B to transmit motion from actuator 304 to move cam driver 386 and, thereby, move cam member 376 between cam-raised position CL and cam-lowered position CO. The operation of the actuator to move the cam member 376 between the cam raised position CL and the cam lowered position CO is described in further detail below.Additionally, it should be understood that FIGS. 20A-21 illustrate non-limiting configurations of the actuator 304, cam driver 386, and actuator drive member 392 including slot 394. In other examples (not shown), the actuator 304, cam driver 386, and actuator drive member 392 including slot 394 can be located elsewhere along the linkage 66, such as adjacent to the brake input device 68. More specifically, in some versions, a single actuator 304 can be used disposed adjacent to one longitudinal end of the base 34 or disposed between the longitudinal ends of the base 34. Furthermore, while in some versions a single actuator 304 can be utilized to operate the override assembly 310 and the braking system 64, in other versions the override assembly 310 and the braking system 64 can use separate actuators that can be similar to one another or of different sizes, torque ratings, configurations (e.g., one rotary and one linear), etc. Other configurations are contemplated. 20A-23C, the override assembly 310 may further include an override member 372 coupled to and extending between the linkage 66 (e.g., the link 72 of the brake system 64) and the cam driver 386 to simultaneously move the cam member 376 from the cam-up position CL to the cam-down position CO when the brake system 64 moves from the released state R to the braked state B. As above, the link 72 of the brake system 64 may be a hexagonal shaft 72, as shown in FIGS. 22A-23C. Also similarly, the link 72 of the brake system 64 may further include a pivot arm 374 extending from the hexagonal shaft 72. The hexagonal shaft 72 can be coupled to the override member 372 (e.g., via the pivot arm 374) to convert rotation of the hexagonal shaft 72 into rotation of the cam driver 386 so as to simultaneously move the cam member 376 from the cam raised position CL to the cam lowered position CO when the brake system 64 moves from the released state R to the braked state B.In some examples, the cam raised position CL can correspond to a steering state S of the linkage 66, the cam raised position CL can correspond to a braking state B of the linkage 66, and the cam intermediate position CI can correspond to a neutral state N of the linkage 66.

[0064] 22A-23C illustrate a sequence for operating the example override assembly 310 to move one or more auxiliary wheels 302 from the deployed position 302D toward the stowed position 302S, thereby at least partially disengaging the one or more auxiliary wheels 302 from the floor surface FS. FIGS. 22A and 23A illustrate the cam member 376 in the cam raised position CL, the brake system 64 in the released state, and the linkage 66 in the steering state S. Thus, the cam member 376 abuts the axle assembly 306 such that the one or more auxiliary wheels 302 are disposed in the deployed position 302D. FIGS. 22B and 23B illustrate the cam driver 386 rotating in response to the linkage 66 moving from the steering state S to the neutral state N. Thus, the cam driver 386 moves the cam member 376 from the cam raised position CL to the cam intermediate position CI. As a result, the cam member 376 moves the axle assembly 306 to move the one or more auxiliary wheels 302 to the intermediate position 302I. FIGS. 22C and 23C show the cam driver 386 rotating in response to the linkage 66 moving from the neutral state N to the braking state B. Thus, the cam driver 386 moves the cam member 376 from the cam intermediate position CI to the cam down position CO to move the one or more auxiliary wheels 302 to the stowed position 302S, and rotation of the hexagonal shaft 72 places the braking system 64 in the braking state B.

[0065] 24A-27C show a sequence of operations of the actuator 304 to move the auxiliary wheels 302 between the extended position 302D and the stowed position 302S. In these examples, the actuator 304 generates torque to rotate the actuator drive member 392 to abut the protrusion 396 of the actuator drive member 392 against the second slot end 394B (shown in FIGS. 24A-27C), thereby simultaneously rotating the actuator drive member 392 and the cam driver 386 to move the cam member 376 toward the cam-down position CO. Conversely, the actuator 304 in this example is also configured to generate torque to rotate the actuator drive member 392 to abut the protrusion 396 of the actuator drive member 392 against the first slot end 304A, thereby simultaneously rotating the actuator drive member 392 and the cam driver 386 to move the cam member 376 toward the cam-up position CL.

[0066] 24A-27C , in some versions, the slot 394 of the cam driver 386 extends along an arc between a first slot end 394A and a second slot end 394B. The arc can be shaped to allow translation of the protrusion 396 within the slot 394 without abutting the first slot end 394A and / or the second slot end 394B in response to movement of the cam member 376 due to operation of the override assembly 310, as described below. Additionally, in some versions, such as those shown in FIGS. 25C and 27A , the actuator 304 is configured to move the cam member 376 to prevent the protrusion 396 from abutting one of the first slot end 394A and the second slot end 394B in response to movement of the cam member 376 due to operation of the override assembly 310, and then move the actuator drive member 392 to the home position PH.

[0067] 24A-25C show the sequence of operation of the actuator 304 to move the auxiliary wheels 302 from the extended position 302D to the stowed position 302S. FIGS. 24A and 25A show one or more auxiliary wheels 302 in the extended position 302D. FIGS. 24A and 25A further show the actuator 304 generating torque to rotate the actuator drive member 392 from the home position PH so that the protrusion 396 abuts against the second slot end 394B of the cam driver 386. Thus, as shown in FIGS. 24B-25C, when the protrusion 396 abuts against the second slot end 394B, the cam driver 386 rotates simultaneously with the actuator drive member 392, moving the cam member 376 from the cam-up position CL toward the cam-down position CO. 24B and 25B show the auxiliary wheel(s) 302 in the intermediate position 302I as the actuator 304 continues to generate torque to rotate the actuator drive member 392 such that the cam driver 386 rotates simultaneously with the actuator drive member 392 to move the cam member 376 toward the cam intermediate position CI. FIGS. 24C and 25C show the auxiliary wheel(s) 302 reaching the stowed position 302S as the actuator 304 continues to generate torque to rotate the actuator drive member 392 such that the cam driver 386 rotates simultaneously with the actuator drive member 392 to move the cam member 376 toward the cam down position CO.

[0068] 25C , the actuator 304 can be configured to return the actuator drive member 392 to the home position PH (e.g., after the cam member 376 reaches the cam down position CO) to prevent the actuator 304 from being back-driven due to operation of the override assembly 310. In other words, returning the actuator drive member 392 to the home position PH allows the protrusion 396 to translate within the slot 394 during operation of the override assembly 310 without the protrusion 396 abutting one of the first slot end 394A and the second slot end 394B such that rotation of the protrusion 396 back-drives the actuator 304.

[0069] Conversely, Figures 26A-27C show the operation sequence of actuator 304 to move auxiliary wheels 302 from stowed position 302S to deployed position 302D. Figures 26C and 27C show one or more auxiliary wheels 302 in stowed position 302S. Figures 26C and 27C further show actuator 304 generating torque to rotate actuator drive member 392 so that protrusion 396 abuts first slot end 394A of cam driver 386. Thus, as shown in Figures 26A-27B, cam driver 386 rotates simultaneously with actuator drive member 392, moving cam member 376 from cam down position CO to cam up position CL. 26B and 27B show the one or more auxiliary wheels 302 in the intermediate position 302I as the actuator 304 continues to generate torque to rotate the actuator drive member 392 such that the cam driver 386 rotates simultaneously with the actuator drive member 392, moving the cam member 376 to the cam intermediate position CI. FIGS. 26A and 27A show the one or more auxiliary wheels 302 reaching the deployed position 302D as the actuator 304 continues to generate torque to rotate the actuator drive member such that the cam driver 386 rotates simultaneously with the actuator drive member 392, moving the cam member 376 toward the cam raised position CL. In some versions, as shown by FIG. 27A , the actuator 304 can be configured to return the actuator drive member 392 to the home position PH (e.g., after the cam member 376 reaches the cam raised position CL) to prevent the actuator 304 from being backdriven due to operation of the override assembly 310.

[0070] 24A-27C, even when actuator 304 effects movement of one or more auxiliary wheels, linkage 66 remains in coordination with cam member 376. Thus, actuator 304 in this example can be configured to move braking system 64 between braking state B and release state R. Thus, in this example, linkage 66 (and braking system 64) is in braking state B when cam member 376 is in cam down position CO, linkage 66 is in neutral state N (and the braking system is in release state R) when cam member 376 is in cam intermediate position CI, and linkage 66 is in steering state S (and the control system is in release state R) when cam member 376 is in cam down position CO.

[0071] 28-29E , in some examples, the brake input device 68 may further include a mechanism for preventing a user from manually engaging the steering state S of the linkage 66. For example, the brake input device 68 may include a shaft 400 operably attached to the linkage 66 for simultaneous movement therewith and a shaft driver 402 coupled to the shaft 400 for simultaneous rotation therewith. The shaft driver 402 may define a shaft driver slot 404 extending between a slot brake end 404B and a slot neutral end 404N. The brake input device 68 may include a pedal 406 operably attached to the shaft 400 for pivotal movement relative to the shaft 400. For example, the pedal 406 may be disposed on the shaft 400 but may not rotate simultaneously with the shaft 400. The pedal 406 may include a pedal protrusion 408 spaced from the shaft 400 and disposed within the shaft driver slot 404. Thus, the pedal protrusion 408 can translate within the shaft driver slot 404 as the pedal 406 pivots relative to the shaft 400, whereby the pedal protrusion 408 abuts against one of the slot brake end 404B and the slot neutral end 404N to transmit motion from the pedal 406 to the shaft 400.

[0072] 29A-29E , in response to a user engaging the first side 406A of the pedal 406, the pedal projection 408 can be configured to rotate about the shaft 400 in a first direction FD, such that abutting the pedal projection 408 against the slot brake end 404B rotates the pedal 406 and the shaft driver 402 simultaneously, moving the shaft 400 and moving the linkage 66 to the braking state B (see the transition from FIG. 29A to FIG. 29B ). Similarly, the pedal projection 408 can be configured to rotate about the shaft 400 in a second direction SD opposite the first direction FD, such that abutting the pedal projection 408 against the slot neutral end 404N rotates the pedal 406 and the shaft driver 402 simultaneously, moving the shaft 400 and moving the linkage 66 to the neutral state N (see the transition from FIG. 29B to FIG. 29D ). 39D , further rotation of the pedal 406 in the second direction SD beyond the rotation shown in FIG. 39D is prevented to prevent a user from manually moving the linkage 66 to the steering state S. For example, the pedal 406 may include a pedal stop (not shown) extending from the pedal 406 to contact the floor surface FS to prevent further rotation of the pedal 406. Preventing a user from manually moving the linkage 66 to the steering state S is advantageous because it may be difficult for a user to generate sufficient torque to move one or more auxiliary wheels 302 to the deployed position 302D. Thus, translation of the pedal protrusion 408 within the shaft driver slot 404 prevents a user from rotating the shaft 400 sufficiently to move the linkage 66 to the steering state S. Also, in some configurations, the brake input device 68 may further include a brake input bias member 410 configured to bias the pedal protrusion 408 of the pedal 406 toward the slot brake end 404B when the linkage 66 is in the neutral state N, such that the pedal 406 is biased toward the flat position (see the transition from Figure 29D to Figure 29E).

[0073] 30A-31C show a portion of a patient transport apparatus 30 including yet another example of an auxiliary wheel assembly 300 and an override assembly 310. Referring to FIGS. 30A-31B, the auxiliary wheel assembly 300 can include an axle assembly 306 for supporting one or more auxiliary wheels 302. Here, the axle assembly 306 is coupled to the base 34 (e.g., to the first base rail 34A and the second base rail 34B) for pivotal movement relative to the base 34 to move the one or more auxiliary wheels 302 between a plurality of auxiliary support positions, including a deployed position 302D and a stowed position 302S. As with the previous example, here the axle assembly 306 includes an axle member 330 including at least one axle shaft 331 for rotatably supporting the at least one auxiliary wheel 302. The axle subassembly 306 may further include a pair of swing arms 332 coupled to and extending between the axle member 330 and the base 34 to facilitate pivotal movement of the axle member 330 relative to the base 34 .

[0074] 30A-31B show a series of one or more auxiliary wheels 302 of an auxiliary wheel assembly 300 moving from a deployed position 302D to a stowed position 302S, causing the one or more auxiliary wheels 302 to at least partially disengage from the floor surface FS. FIGS. 30A and 31A show the one or more auxiliary wheels 302 of the auxiliary wheel assembly 300 in the deployed position 302D. FIGS. 30B and 31B show the one or more auxiliary wheels 302 of the auxiliary wheel assembly 300 in the stowed position 302S.

[0075] The override assembly 310 of this example includes a cam assembly 500 operably attached to the axle assembly 306 to move the axle assembly 306 relative to the base 34, thereby moving one or more auxiliary wheels 302 between a stowed position 302S and a deployed position 302D. The cam assembly 500 is configured to move between a plurality of cam positions, including a cam down position CO, in which the cam assembly 500 moves the axle assembly 306 to move the auxiliary wheels 302 to the stowed position 302S, and a cam up position CL, in which the cam assembly 500 moves the axle assembly 306 to move the auxiliary wheels 302 to the deployed position 302D. With reference to FIGS. 32-37 , the cam assembly 500 may include a coupling link 502 operably attached to the axle assembly 306. For example, the axle assembly 306 may include a mounting bracket 504, and the coupling link 502 may be pivotally attached to the mounting bracket via a pin 506. Of course, other configurations for pivotally mounting coupling link 502 to axle assembly 306 are contemplated. Cam assembly 500 may also include an intermediate link 508 coupled to coupling link 502 (e.g., via pin 506) for pivotal movement relative to coupling link 502. Cam assembly 500 may further include a cam member 510. Cam member 510 may be coupled to an override shaft 512 supported by base 34 for rotation about an override axis 514. Cam member 510 is coupled to intermediate link 508 (e.g., via pin 506) such that coupling link 502 and intermediate link 508 are configured to pivot relative to one another in response to rotation of cam member 510 to extend cam assembly 500 between a cam down position CO and a cam up position CL.

[0076] As best shown in FIG. 36 , the intermediate link 508 may include a first locking portion 516 configured to abut the cam member 510 to define a range of rotation of the intermediate link 508 relative to the cam member 510. For example, the first locking portion 516 may include a resilient locking member 518 positioned to abut the cam member 510, although other configurations for defining a range of rotation of the intermediate link 508 relative to the cam member 510 are contemplated. With continued reference to FIG. 36 , the coupling link 502 may include a second locking portion 520 configured to abut the intermediate link 508 to define a range of rotation of the coupling link 502 relative to the axle assembly 306. Additionally, the coupling link 502 may further include a third locking portion 521 configured to abut the axle assembly 306 to define a range of rotation of the coupling link 502 relative to the axle assembly 306.

[0077] 32-37 , auxiliary wheel assembly 300 may further include a roller arm 522 extending between a first roller arm end portion 522A operably attached to base 34 for pivotal movement relative to base 34, and a second roller arm end portion 522B. Roller arm 522 may include a roller 524 configured to abut cam member 510 and rotate to enable cam assembly 500 to move between a plurality of cam positions. For example, roller 524 may be disposed between first roller arm end portion 522A and second roller arm end portion 522B. The auxiliary wheel assembly 300 may further include a roller arm bias member 526 extending between one of the first roller arm end portion 522A and the second roller arm end portion 522B and the axle assembly 306 and biasing the roller 524 against the cam member 510, which in turn biases the axle assembly 306 to move the auxiliary wheel 302 upward toward the stowed position 302S. The roller arm bias member 526 shown in Figures 32-37 is embodied as a spring, although other configurations are contemplated, including a strut, a gas spring, or the like, to bias the roller 524 against the cam member 510 and bias the axle assembly 306 upward to move the auxiliary wheel 302 toward the stowed position 302S.

[0078] 36 , the auxiliary wheel assembly 300 may further include a cam damper 528 that extends between the cam member 510 and the base 34 and damps movement of the cam member 510 relative to the base 34. Thus, by damping movement of the cam member 510 relative to the base 34, mechanical shock during movement of the axle assembly 306 and / or linkage 66 is reduced. Other configurations are contemplated for limiting mechanical shock during movement of the axle assembly 306 and / or linkage 66. FIG. 37 shows another exemplary configuration that includes a first roller arm damper 530A that couples the first roller arm end portion 522A to the base 34 and extends between the first roller arm end portion 522A and the base 34 to damp movement of the roller arm 522 relative to the cam member 510 and / or base 34. The configuration of FIG. 37 may further include a second roller arm damper 530B extending between the second roller arm end portion 522B and the axle assembly 306 to damp movement of the roller arm 522 relative to the axle assembly 306 and / or cam member 510.

[0079] As best shown in FIGS. 36 and 37 , cam member 510 can define a plurality of detents configured to engage rollers 524 to retain cam assembly 500 in the corresponding cam positions. For example, cam member 510's plurality of detents can define rounded recesses positioned to at least partially receive rollers 524 while cam assembly 500 is in one of the plurality of cam positions. For example, cam member 510's plurality of detents can include a cam down detent 532 for retaining cam assembly 500 in cam down position CO. cam member 510's plurality of detents can also include a cam up detent 534 for retaining cam assembly 500 in cam up position CL. cam member 510's plurality of detents can further include a cam intermediate detent 536 positioned between cam down detent 532 and cam up detent 534 for retaining cam assembly 500 in cam intermediate position CI between cam up position CL and cam down position CO.

[0080] 32 and 34 , the override assembly 310 further includes an override member 372 operably attached to the linkage 66 of the braking system 64 and the cam member 510 to simultaneously move the cam assembly 500 from the cam raised position CL to the cam lowered position CO as the linkage 66 moves from the steering state S to the braking state B. For example, the override member 372 can be coupled at a first end 372A to the linkage 66 and at a second end 372B to the override shaft 512 (which supports the cam member 510) so that the linkage 66 rotates simultaneously with the override shaft 512. Also, in the configuration shown, a timing link 578 can extend between the override member and the link 72 at the other end of the patient transport apparatus 30 to ensure that both links 72 rotate simultaneously between the steering state S, the neutral state N, and the braking state B. In some examples, the override assembly 310 further includes a linkage damper 538 operably attached to the linkage 66 and the base 34 (e.g., via the override member 372 or the timing link 578) to damp movement of the linkage 66 and / or the cam assembly 500 relative to the base 34 to further limit mechanical shock as described above.

[0081] Thus, in this example, when the linkage 66 is in the steering state S, the cam assembly 500 is in the cam-up position CL to move the axle assembly 306 to move the auxiliary wheels 302 to the deployed position 302D. Additionally, when the linkage 66 is in the braking state B, the cam assembly 500 is in the cam-down position CO to move the auxiliary wheels 302 to the stowed position 302S. Furthermore, when the linkage 66 is in the neutral state N, the cam assembly 500 is in the cam-intermediate position CI. In these examples, when the cam assembly 500 is in the cam-intermediate position CI, the roller arm bias member 526 urges the axle assembly 306 to move the auxiliary wheels 302 to the stowed position 302S. In other words, when the linkage 66 is in the neutral state N or the brake state B (and thus when the cam assembly 500 is in the cam intermediate position CI or the cam down position CO), the roller arm bias member 526 urges the axle assembly 306 to move the auxiliary wheel 302 to the stowed position 302S. The movement of the cam assembly 500 between the multiple cam positions, and the resulting movement of the axle assembly 306 and auxiliary wheel 302, is described in further detail below with respect to Figures 38A-50C.

[0082] 32-37 , auxiliary wheel assembly 300 further includes a cam driver 540 operably attached to cam member 510 for simultaneous rotation therewith. For example, cam driver 540 may be coupled to override shaft 512, although other configurations are contemplated. As best shown in FIGS. 32 and 34 , actuator 304 may be operably attached to cam driver 540 to move cam assembly 500 between a plurality of cam positions (e.g., cam down position CO, cam intermediate position CI, and cam up position CL). As described above, actuator 304 may be configured to generate torque about actuator axis 390. To operably attach actuator 304 to cam driver 540, auxiliary wheel assembly 300 may further include an actuator drive member 542 coupled to the actuator for simultaneous rotation with actuator 304 about actuator axis 390. As described in further detail below, the actuator drive member 542 can define a slot 544 extending between a first slot end 544A and a second slot end 544B. Additionally, the cam driver 540 can include a protrusion 546 spaced from the actuator shaft 390 and disposed within the slot 544 of the actuator drive member 542, the protrusion 546 translating within the slot 544 and abutting one of the first slot end 544A and the second slot end 544B to transfer motion from the actuator 304 to the cam member 510 to move the cam assembly 500 between a plurality of cam positions.

[0083] 49A-50C, the actuator 304 can be configured to generate torque to rotate the actuator drive member 542 to abut the protrusion 546 of the cam driver 540 against the first slot end 544A, thereby simultaneously rotating the actuator drive member 542 and the cam driver 540 to move the cam member 510, which moves the cam assembly 500 to the cam raised position CL and the linkage 66 to the steering state S. Similarly, the actuator 304 can be configured to generate torque to rotate the actuator drive member 542 to abut the protrusion 546 of the cam driver 540 against the second slot end 544B, thereby simultaneously rotating the actuator drive member 542 and the cam driver 540 to move the cam member 510, which moves the cam assembly 500 toward the cam lowered position CO and moves the linkage 66 to one of the neutral state N and the brake state B.

[0084] 38A, 38B, and 38C, in this example, the brake input device 68 includes a first pedal 548 coupled to the linkage 66 (e.g., link 72) of the braking system 64 for simultaneous movement therewith. In these examples, the first pedal 548 is configured for user engagement to move the linkage 66 of the braking system 64 in a first direction D1 between a first pedal steering position P1S, a first pedal neutral position P1N, and a first pedal braking position P1B. At the first pedal steering position P1S (shown in FIG. 38A), the linkage 66 is in a steering state S. At the first pedal neutral position P1N (shown in FIG. 38B), the linkage 66 is in a neutral state N. At the first pedal braking position P1B (shown in FIG. 38C), the linkage 66 is in a braking state B.

[0085] As described above, the override assembly 310 is configured to raise one or more auxiliary wheels 302 and at least partially disengage the one or more auxiliary wheels 302 from the floor surface FS in response to movement of the linkage 66 of the braking system 64 from the steering state S toward one of the neutral state N and the braking state B. Thus, the weight of the patient transport device 30 is transferred from the auxiliary wheels 302 to the wheels 58, thereby enabling the brakes 62 of the wheels 58 to prevent movement of the base 34 along the floor surface FS, thereby preventing any lifting of the wheels 58 via the auxiliary wheels 302 (particularly when the linkage 66 is in the steering state S). FIGS. 38A-40C illustrate operation of the override assembly 310 to move the auxiliary wheels 302 from the deployed position 302D to the stowed position 302S as the linkage 66 of the braking system 64 moves from the steering state S, through the neutral state N, and finally to the braking state B.

[0086] 38A, 39A, and 40A illustrate operation of this example patient transport device 30 with auxiliary wheels 302 in the deployed position 302D. As best shown in FIG. 38A, here, first pedal 548 is in first pedal steering state P1S such that linkage 66 is disposed in steering state S, causing override member 372 (moving simultaneously with linkage 66 and override shaft 512) to position cam member 510 to place cam assembly 500 in cam raised position CL. Thus, coupling link 502 and intermediate link 508 of cam assembly 500 are disposed in an extended configuration relative to one another such that coupling link 502 abuts axle assembly 306, biasing auxiliary wheels 302 to the deployed position 302D.

[0087] 38B, 39B, and 40B illustrate user engagement with the first pedal 548 (indicated by arrow 550), which moves the linkage 66 in a first direction D1 (i.e., toward braking state B). Here, user engagement 550 with the first pedal 548 causes the first pedal 548 to move to a first pedal neutral state P1N such that the linkage 66 moves to neutral state N, thereby causing the override member 372 (moving simultaneously with the linkage 66 and override shaft 512) to position the cam member 510 to place the cam assembly 500 in the cam intermediate position CI. Thus, as best shown in FIG. 40B, the roller arm bias member 526 urges the axle assembly 306 upward to move the auxiliary wheel 302 to the stowed position 302S. In particular, the coupling link 502 and the intermediate link 508 move relative to one another to a retracted configuration, allowing movement of the axle assembly 306 upward. 39B, as override shaft 512 rotates to move cam assembly 500 to cam intermediate position CI, cam driver 540 also rotates. As shown in FIG. 39B, during the movement shown, protrusion 546 of cam driver 540 orbits within slot 544 of actuator drive member 542 about actuator axis 390 such that protrusion 546 does not abut either first slot end 544A or second slot end 544B, and therefore operation of override assembly 310 does not back-drive actuator 304.

[0088] 33, 39A, 39B, and 39C, the patient transport apparatus 30 may further include a locking member 552 disposed on one of the base 34 and the axle assembly 306. The locking member 552 may be positioned to abut the other of the base 34 and the axle assembly 306 to define a range of motion of the axle assembly 306 toward the base 34 with the auxiliary wheels 302 in the stowed position 302S.

[0089] 38C, 39C, and 40C illustrate further user engagement with first pedal 548 (indicated by arrow 550), which moves linkage 66 in first direction D1 (i.e., toward braking state B). Further user engagement 550 with first pedal 548 now causes first pedal 548 to move to first pedal braking state P1B, such that linkage 66 moves to braking state B, thereby causing override member 372 (moving simultaneously with linkage 66 and override shaft 512) to position cam member 510 to place cam assembly 500 in cam down position CO. Now, as best shown in FIG. 40C, roller arm bias member 526 continues to bias axle assembly 306 upward to hold auxiliary wheel 302 in stowed position 302S. 39C, override shaft 512 continues to rotate to move cam assembly 500 to cam down position CO, and cam driver 540 also continues to rotate. As shown in FIG. 39C, during the movement shown, protrusion 546 of cam driver 540 continues to orbit within slot 544 of actuator drive member 542 about actuator axis 390 such that protrusion 546 does not abut either first slot end 544A or second slot end 544B, and therefore operation of override assembly 310 does not back-drive actuator 304.

[0090] It may be desirable to move the linkage 66 of the braking system 64 from the braking state B to a neutral state N to allow the wheels 58 to rotate relative to the floor surface FS. Accordingly, with reference to FIGS. 41-43 , the brake input device 68 may also include a second pedal assembly 554 coupled to the linkage 66 of the braking system 64. The second pedal assembly 554 may be configured for user engagement to move the linkage 66 of the braking system 64 in a second direction D2 opposite the first direction D1. For example, the second pedal assembly 554 may include a second pedal mount 556 extending from the base 34 and a second pedal 558 extending between a second pedal interface 558A configured for user engagement and a second pedal connection end 558B. The second pedal 558 can be mounted to the second pedal mount 556 between a second pedal interface 558A and a second pedal connecting end 558B and supported for rotation relative to the second pedal mount 556. The second pedal assembly 554 can also include a second pedal drive link 560 coupled to the second pedal connecting end 558B for rotation relative to the second pedal connection end 558B. As best shown in FIG. 43 , the second pedal drive link 560 can define a second pedal drive link slot 562 extending between a first pedal slot end 562A and a second pedal slot end 562B. Here, the linkage 66 of the braking system 64 can include a linkage protrusion 564 disposed within the second pedal drive link slot 562 for movement within the second pedal drive link slot 562, thereby slidably coupling the second pedal 558 to the linkage 66. Thus, in response to user engagement with the second pedal interface 558A, the first pedal slot end 562A is configured to abut against the linkage protrusion 564 and transmit motion from the second pedal 558 to the linkage 66 of the braking system 64, causing the linkage 66 to move in the second direction D2.Additionally, the brake input device 68 may further include a second pedal bias member 566 configured to urge the second pedal interface upward to abut the second pedal slot end 562B against the linkage protrusion 564 when there is no user engagement with the second pedal interface 558A.

[0091] 44A-48 illustrate the operation of the second pedal assembly 554 to move the linkage 66 of the braking system 64 from braking state B to neutral state N. With reference to FIG. 44A, the linkage 66 of the braking system 64 is in braking state B, and the second pedal interface 558A is in second pedal braking position P2B. In second pedal braking position P2B, the second pedal interface 558A is configured for user engagement. With reference to FIGS. 44B-45, in response to user engagement with the second pedal interface 558A (indicated by arrow 568), the second pedal 558 is configured to move the second pedal drive link 560 such that the first pedal slot end 562A abuts the linkage protrusion 564. 44C-46 , in response to further user engagement with the second pedal interface 558A (indicated by arrow 568) to a second pedal neutral position P2N, the second pedal 558 and second pedal drive link 560 are configured to move the linkage 66 of the braking system 64 in a second direction D2 such that the linkage 66 of the braking system 64 moves from Braking State B to Neutral State N. Finally, with reference to FIG. 44D , once the second pedal 558 and second pedal drive link 560 move the linkage 66 of the braking system 64 to Braking State B (i.e., upon removal of user engagement with the second pedal interface 558A), the second pedal biasing member 566 can be configured to bias the second pedal interface 558A upward, causing the second pedal slot end 562B to abut against the linkage protrusion 564. 44C to prevent a user from manually moving the linkage 66 to the steering state S. For example, the second pedal assembly 554 may include a pedal stop 570 extending from the base 34 to prevent further rotation of the second pedal 558. Preventing a user from manually moving the linkage 66 to the steering state S is advantageous because it may be difficult for a user to generate sufficient torque to move one or more auxiliary wheels 302 to the deployed position 302D.

[0092] 49A-50C, as described above, the actuator 304 can be configured to generate torque to rotate the actuator drive member 542 against one of the first slot end 544A and the second slot end 544B and the protrusion 546 of the cam driver 540, thereby simultaneously rotating the actuator drive member 542 and the cam driver 540 to move the cam member 510 and move the cam assembly 500 between a plurality of cam positions, and consequently, the linkage 66 of the braking system between the steering state S, the neutral state N, and the braking state B. Thus, advantageously, in this configuration, the actuator 304, in combination with the components described herein in the context of this example, can move the braking system between the braked and released states, thereby eliminating the need for a separate electric braking assembly 70.

[0093] Additionally, in some versions, slot 544 of actuator drive member 542 extends along an arc between first slot end 544A and second slot end 544B. The arc can be shaped to allow translation of protrusion 546 within slot 544 without abutting first slot end 544A and / or second slot end 544B in response to movement of cam member 510 due to operation of override assembly 310, as described above. Additionally, in some versions, such as those shown in FIGS. 49A and 50A , actuator 304 is configured to move cam member 510 to prevent protrusion 546 from abutting one of first slot end 544A and second slot end 544B in response to movement of cam member 510 due to operation of override assembly 310, and then move actuator drive member 542 to the home position.

[0094] For example, Figures 49A and 50A show the actuator drive member 542 in the home position PH and the cam assembly 500 in the cam intermediate position CI (and thus the linkage 66 of the braking system 64 in the neutral state N). Referring to Figures 49B and 50B, the actuator 304 can be configured to generate torque to rotate the actuator drive member 542 to abut the protrusion 546 of the cam driver 540 against the second slot end 544B, thereby simultaneously rotating the actuator drive member 542 and the cam driver 540 to move the cam member 510 and move the cam assembly 500 toward the cam down position CO (and thus move the linkage 66 to the braking state B). 49C and 50C, the actuator 304 can also be configured to generate torque to rotate the actuator drive member 542 to abut the protrusion 546 of the cam driver 540 against the first slot end 544A, thereby simultaneously rotating the actuator drive member 542 and the cam driver 540 to move the cam member 510 and move the cam assembly 500 to the cam raised position CL (thereby moving the linkage 66 of the braking system 64 to the steering state S). It should also be understood that the actuator 304 can be configured to rotate the actuator drive member 542 in a direction necessary to move the cam assembly 500 to the cam intermediate position CI (between the cam lowered position CO and the cam raised position CL), thereby moving the linkage 66 to the neutral state N. It should further be understood that after each operation of the actuator 304 to move the cam assembly 500 and linkage 66 of the braking system 64, the actuator 304 can be configured to move the actuator drive member 542 back to the home position PH in response to movement of the cam member 510 due to operation of the override assembly 310 to prevent the protrusion from abutting one of the first slot end 544A and the second slot end 544B.

[0095] Additionally, in some configurations, it may be desirable to know the angular position of the actuator drive member 542 and / or the override shaft 512 (and thus the cam member 510) to inform operation of the actuator 304. Accordingly, in some versions, the override assembly 310 may include an actuator drive member position sensor 572 (shown schematically in FIG. 49A ) configured to detect the angular position of the actuator drive member 542 and communicate with a controller of the patient transport apparatus 30 to operate the actuator 304 based on the sensed position of the actuator drive member 542. The actuator drive member position sensor 572 may be implemented as an angular encoder, a limit switch, or, if the actuator 304 is a brushless electric motor, by counting motor pulses. The angular position of the actuator drive member 542 may also be verified relative to the angular position of the override shaft 512. Of course, other configurations of the actuator drive member position sensor 572 for verifying the angular position of the actuator drive member 542 are contemplated. Similarly, the override assembly 310 may additionally or alternatively include a cam member position sensor 574 (shown schematically in FIG. 50A ) configured to detect the angular position of the override shaft 512 (and hence the angular position of the cam member 510 and linkage 66 of the braking system 64) and to communicate with a controller of the patient transport apparatus 30 to operate the actuator 304 based on the sensed position of the override shaft 512. The cam member position sensor 574 may be implemented as an angular encoder, a limit switch, or the like. The angular position of the override shaft may also be verified relative to the angular position of the actuator drive member 542. Of course, other configurations of the cam member position sensor 574 for verifying the angular position of the override shaft 512 are contemplated.Also, in some versions, the axle assembly 306 may include an object collision sensor 576 configured to detect premature contact of the coupling link 502 with the axle assembly 306 when the auxiliary wheel 302 is moved to the deployed position 302D due to a foreign object (e.g., a caregiver's foot) being under the auxiliary wheel 302. The object collision sensor 576 may be, for example, a limit switch or the like. The object collision sensor 576 may be configured to communicate with a controller of the patient transport device 30 to terminate operation of the actuator 304 if a premature collision with a foreign object is detected.

[0096] Several configurations have been discussed in the above description. However, the configurations discussed herein are not intended to be exhaustive or to limit the invention to any particular form. The terminology used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations are possible in light of the above teachings, and the invention may be practiced otherwise than as specifically described.

[0097] The present disclosure also includes the following sections which may be specifically implemented as described in more detail with reference to the above configurations and drawings, with particular features being set out in the subsections. section I. A patient carrier comprising: a support structure comprising a base and a patient support deck; a plurality of wheels coupled to the base for supporting movement of the patient transport device across the floor surface; 1. A braking system including a linkage coupled to one or more of a plurality of wheels, the braking system comprising: a braking state that prevents movement of the base along the floor surface; The liberated state and a braking system operable between a brake input device in communication with the linkage and configured for user engagement to change operation of the braking system between a braking state and a released state, the linkage being in a braking state when the braking system is in the braking state, the brake input device being further configured to move the linkage between a neutral state and a steering state in which the braking system is in the released state; 1. An auxiliary wheel assembly comprising: an auxiliary wheel; an axle assembly supporting the auxiliary wheel, the axle assembly coupled to the base for pivotal movement relative to the base; and an actuator configured to move the axle assembly and the auxiliary wheel between a plurality of auxiliary support positions, the plurality of auxiliary support positions including: a deployed position, in which the auxiliary wheels engage the floor surface to at least partially support movement of the patient transport device across the floor surface; a storage position in which the auxiliary wheels are spaced apart from the floor surface; an auxiliary wheel assembly including: an override assembly coupled to the linkage of the braking system and the auxiliary wheel assembly, the override assembly responsive to movement of the linkage from the steering state toward one of the neutral state and the brake state to move the auxiliary wheels from the deployed position to the stowed position and at least partially disengage the auxiliary wheels from the floor surface; A patient transport device comprising: II. The override assembly further comprises a cam assembly operably attached to the axle assembly for moving the axle assembly relative to the base, the cam assembly comprising: a cam-down position in which the auxiliary wheels are in a stowed position; a cam raised position in which the cam assembly moves the auxiliary wheels to a deployed position; 10. The patient transport device of claim I, configured to move between a plurality of cam positions, including: III. The patient transport device described in clause II, wherein the cam assembly comprises a connecting link operably attached to the axle assembly, an intermediate link coupled to the connecting link for pivotal movement relative to the connecting link, and a cam member coupled to the intermediate link, the connecting link and intermediate link configured to pivot relative to one another in response to rotation of the cam member to extend the cam assembly between a cam lowered position and a cam raised position. IV. The patient transport device of clause III, wherein the auxiliary wheel assembly further comprises a roller arm extending between a first roller arm end portion operably attached to the base for pivotal movement relative to the base and a second roller arm end portion, the roller arm including a roller configured to abut the cam member and rotate to enable the cam assembly to move between a cam-down position and a cam-up position. V. The patient transport device of clause IV, wherein the auxiliary wheel assembly further comprises a roller arm bias member extending between one of the first roller arm end portion and the second roller arm end portion and the axle assembly, urging the roller against the cam member and urging the axle assembly to move the auxiliary wheel toward the stowed position. VI. The patient transport device of clause V, wherein the auxiliary wheel assembly further comprises a cam damper extending between the cam member and the base and damping movement of the cam member relative to the base. VII. The cam member defines a plurality of detents configured to engage the rollers to retain the cam assembly in the corresponding cam position, the plurality of detents comprising: a cam down detent for retaining the cam assembly in the cam down position; a cam raise detent for retaining the cam assembly in the cam raised position; 4. The patient transport device of claim V or VI, comprising: VIII. The patient transport device of clause VII, wherein the plurality of detents further includes a cam intermediate detent disposed between the cam lowering detent and the cam raising detent for retaining the cam assembly at a cam intermediate position between the cam raised position and the cam lowered position. IX. The patient transport device of paragraph VIII, wherein when the cam assembly is in the cam intermediate position, the roller arm bias member biases the axle assembly to move the auxiliary wheels to the stowed position. X. The patient transport device of clause IX, further comprising an override assembly operably attached to the linkage of the braking system and the cam member, the override member simultaneously moving the cam assembly between the cam-up position and the cam-down position as the linkage moves between the steering state and the braking state. XI. The patient transport device of clause X, wherein the override assembly further comprises a linkage damper operably attached to the linkage and the base, damping movement of the linkage relative to the base. XII. The patient transport device of clause X or XI, wherein the auxiliary wheel assembly further comprises a cam driver coupled to the cam member for simultaneous rotation therewith. XIII. The patient transport device of clause XII, wherein the actuator is operably attached to the cam driver to move the cam assembly between a plurality of cam positions. XIV. The actuator is configured to generate a torque about the actuator axis; The auxiliary wheel assembly further includes an actuator drive member coupled to the actuator for co-rotation with the actuator about the actuator axis, the actuator drive member defining a slot extending between a first slot end and a second slot end; The patient transport device of clause XIII, wherein the cam driver includes a protrusion spaced from the actuator shaft and disposed within a slot in the actuator drive member, the protrusion translating within the slot and abutting one of the first slot end and the second slot end to transfer motion from the actuator to the cam member to move the cam assembly between the plurality of cam positions. XV. The actuator is configured to generate torque to rotate the actuator drive member to abut the protrusion of the cam driver against the first slot end, thereby simultaneously rotating the actuator drive member and the cam driver to move the cam member, moving the cam assembly to the cam raised position, and moving the linkage to the steering state; The patient transport device of clause XIV, wherein the actuator is configured to generate torque to rotate the actuator drive member to abut the protrusion of the cam driver against the second slot end, thereby simultaneously rotating the actuator drive member and the cam driver to move the cam member, moving the cam assembly toward a cam-down position, and moving the linkage to one of a neutral state and a brake state. XVI. The patient transport device of clause XV, wherein the slot of the actuator drive member extends along an arc between a first slot end and a second slot end, the arc being shaped to allow the protrusion to translate within the slot without abutting one of the first slot end and the second slot end in response to movement of the cam member due to operation of the override assembly. XVII. The patient transport device of clause XVI, wherein the actuator is configured to, in response to movement of the cam member due to operation of the override assembly, move the cam member to prevent the protrusion from abutting one of the first slot end and the second slot end, and then move the actuator drive member to a home position. XVIII. The patient transport device of clause XVI or XVII, wherein the override assembly further comprises an actuator drive member position sensor configured to detect an angular position of the actuator drive member, and the patient transport device is configured to operate the actuator based on the sensed position of the actuator drive member. XIX. The patient transport device of any one of clauses XVI to XVIII, wherein the override assembly further comprises a cam member position sensor configured to detect an angular position of the cam member, and the patient transport device is configured to operate the actuator based on the detected position of the cam member. XX. The brake input device further comprises a first pedal coupled to the linkage of the braking system for simultaneous movement with the linkage, the first pedal moving the linkage of the braking system in a first direction: a first pedal steering position in which the link mechanism is in a steering state; a first pedal neutral position in which the first pedal moves the linkage to a neutral state in a first direction; a first pedal braking position in which the first pedal moves the linkage in a first direction to a braking state; 10. The patient transport device of any one of clauses XVI to XIX, configured for user engagement to move the patient transport device between XXI. The patient transport apparatus of clause XX, further comprising a second pedal assembly coupled to the linkage of the braking system and configured for user engagement to move the linkage of the braking system in a second direction opposite the first direction. XXII. The second pedal assembly a second pedal mount extending from the base; a second pedal extending between a second pedal interface configured for user engagement and a second pedal connection end, the second pedal being mounted to a second pedal mount between the second pedal interface and the second pedal connection end and supported for rotation relative to the second pedal mount; a second pedal drive link coupled to the second pedal connection end for rotation relative to the second pedal connection end, the second pedal drive link defining a second pedal drive link slot extending between a first pedal slot end and a second pedal slot end, the braking system linkage including a linkage protrusion disposed within the second pedal drive link slot for movement within the second pedal drive link slot, the first pedal slot end configured to abut the linkage protrusion in response to user engagement with the second pedal interface to transfer motion from the second pedal to the braking system linkage and move the linkage in a second direction; 20. The patient transport device of claim XXI, comprising: XXIII. The patient transport apparatus of clause XXII, wherein the brake input device further comprises a second pedal biasing member configured to urge the second pedal interface upward to abut the second pedal slot end against the linkage protrusion when there is no user engagement with the second pedal interface. XXIV. The patient transport device of clause XXIII, wherein when the linkage is in a braking state, the second pedal interface is in a second pedal braking position and is configured for user engagement to move the second pedal drive link such that the first pedal slot end abuts the linkage protrusion to move the linkage in a second direction from the braking state to a neutral state. XXV. A patient transport device, comprising: a support structure comprising a base and a patient support deck; a plurality of wheels coupled to the base for supporting movement of the patient transport device across the floor surface; 1. A braking system including a linkage coupled to one or more of a plurality of wheels, the braking system comprising: a braking state that prevents movement of the base along the floor surface; The liberated state and a braking system operable between a brake input device in communication with the linkage and configured for user engagement to change operation of the braking system between a braked state and a released state; 1. An auxiliary wheel assembly coupled to a support structure, the auxiliary wheel assembly comprising: an auxiliary wheel; and an actuator configured to move the auxiliary wheel between a plurality of auxiliary support positions, the plurality of auxiliary support positions including: a deployed position, in which the auxiliary wheels engage the floor surface to at least partially support movement of the patient transport device across the floor surface; a storage position in which the auxiliary wheels are spaced apart from the floor surface; an auxiliary wheel assembly including: a linkage of the braking system and coupled to the auxiliary wheel assembly for moving the auxiliary wheels away from the deployed position toward the stowed position in response to movement of the braking system from the released state toward the braked state; preventing movement of the base along the floor surface under braking conditions; and at least partially disengaging the auxiliary wheels from the floor surface; At the same time, override assembly and A patient transport device comprising: XXVI. The patient transport device of clause XXV, wherein the auxiliary wheel assembly further comprises an auxiliary frame coupled to the base, the auxiliary wheel and the actuator operably attached to the auxiliary frame. XXVII. Auxiliary frame a first auxiliary rail extending longitudinally along the patient transport device and coupled to the first base rail of the base; a second auxiliary rail extending longitudinally along the patient transport device and coupled to the second base rail of the base; a first cross member extending between the first auxiliary rail and the second auxiliary rail at a first end of the auxiliary wheel assembly; a second cross member extending between the first auxiliary rail and the second auxiliary rail at the second end of the auxiliary wheel assembly; 20. The patient transport device of claim XXVI, comprising: XXVIII. The patient transport device of clause XXVII, wherein the auxiliary wheel assembly further comprises an axle assembly supporting the auxiliary wheel, the axle assembly being operably attached to the first cross member for pivotal movement relative to the first cross member to move the auxiliary wheel between a plurality of auxiliary support positions including a deployed position and a stowed position. XXIX. The patient transport device of clause XXVIII, wherein the actuator is coupled to the axle assembly at a first actuator end and operably attached to the second cross member at a second actuator end and configured to move the axle assembly to move the auxiliary wheels between the deployed position and the stowed position. XXX.Axle assembly is a first axle subassembly rotatably supporting the auxiliary wheel, the first axle subassembly being operably mounted to the first equipment for pivotal movement relative to the first cross-member; a first axle subassembly and a second axle subassembly operably mounted to the first cross member for pivotal movement relative to the first cross member, the first actuator end being coupled to the second axle assembly for moving the axle assembly to move the auxiliary wheels between a deployed position and a stowed position; 20. The patient transport device of claim XXIX, further comprising: XXXI. The patient transport device of clause XXX, further comprising a first spring cartridge disposed between the first axle subassembly and the first cross-member, biasing the axle assembly toward the deployed position and allowing the axle assembly to deflect toward the stowed position in response to engagement of the auxiliary wheel with an uneven floor surface. XXXII. The patient transport device of clause XXX or XXXI, further comprising a second spring cartridge disposed between the second axle subassembly and the first axle subassembly, enabling the second axle subassembly to deflect relative to the first axle subassembly in response to engagement of the auxiliary wheel with an uneven floor surface. XXXIII. The patient transport device of any one of clauses XXX to XXXII, wherein the first cross-member further comprises a first pair of brackets extending longitudinally from a first end of the first cross-member and a second pair of brackets extending longitudinally from a second end of the first cross-member, the first pair of brackets and the second pair of brackets defining a coaxial bore that defines a pivot axis. XXXIV. The patient transport device of clause XXXIII, wherein the first axle subassembly is coupled to the first and second pairs of brackets via one or more shafts disposed within the coaxial bore for pivotal movement about the pivot axis. XXXV. The patient transport device of clause XXXIII, wherein the second axle subassembly is coupled to the first and second pairs of brackets via a shaft disposed within the coaxial bore for pivotal movement about the pivot axis. XXXVI. The auxiliary wheel assembly further comprises an axle assembly supporting the auxiliary wheel, the axle assembly coupled to the auxiliary frame for pivotal movement relative to the auxiliary frame to move the auxiliary wheel between a plurality of auxiliary support positions including a deployed position and a stowed position; The patient transport device of any one of clauses XXVI to XXXV, wherein the actuator is coupled to the axle assembly at a first actuator end and operably attached to the auxiliary frame at a second actuator end, and configured to move the axle assembly to move the auxiliary wheels between the deployed position and the stowed position. XXXVII. Override Assembly a carriage extending longitudinally between a first carriage end spaced from the auxiliary frame and a second carriage end coupled to the auxiliary frame; a second actuator end coupled to the actuator and engaging the carriage; an operating position, in which the second actuator end is fixed in spaced relation at a first distance from the auxiliary frame to support the actuator for moving the auxiliary wheels between the deployed position and the stowed position; an override position, wherein the second actuator end is fixed in spaced relation to move the actuator to at least partially disengage the auxiliary wheel from the floor surface at a second distance from the auxiliary frame that is less than the first distance; a trolley for guiding movement of the second actuator end along the carriage between the 36. The patient transport device of claim XXXVI, further comprising: XXXVIII. The override assembly further comprises an override linkage coupled to and disposed between the auxiliary frame and the second actuator end, the override linkage comprising: an extended state in which the override linkage moves the second actuator end to an operating position; a folded state in which the override linkage moves the second actuator end to an override position; 37. The patient transport device of claim 36, configured to move between: XXXIX. The patient transport apparatus of clause XXXVIII, wherein the linkage is in a braking state when the braking system is in a braking state, and the brake input device is further configured to move the linkage between a neutral state and a steering state when the braking system is in a released state. XL. The patient transport device of clause XXXIX, wherein the override assembly further comprises an override member coupled to and extending between the linkage and the override linkage of the braking system, for simultaneously moving the override linkage from an extended state to a folded state as the linkages move from a steering state to a braking state. XLI. Override link mechanism a first link including a first link mounting end coupled to the second actuator end for pivotal movement relative to the second actuator end and a first link pivot end; a second link including a second link mounting end coupled to the sub-frame for pivotal movement relative to the sub-frame and a second link pivot end coupled to the first link pivot end for pivotal movement relative to the first link pivot end; 3. The patient carrier of claim XXXIX or XL, comprising: XLII. The patient transport device of clause XLI, wherein the override assembly further comprises an override member coupled to and extending between the linkage of the braking system and one of the first link pivot end and the second link pivot end, and configured to simultaneously move the override linkage from the extended state to the folded state when the linkage moves from the steering state to the braking state. XLIII. The linkage of the braking system is a hexagonal shaft that rotates in response to movement of the linkage between the braking and steering states; a pivot arm extending from the hexagonal shaft and coupled to the override member, the pivot arm converting rotation of the hexagonal shaft into translation of the override member to simultaneously move the override linkage from an extended state to a folded state as the linkage moves from a steering state to a braking state; 4. The patient transport device of claim XLII, comprising: XLIV. The patient transport device of any one of clauses XXV to XLIII, wherein the auxiliary wheel assembly further comprises an axle assembly supporting the auxiliary wheel, the axle assembly coupled to the base for pivotal movement relative to the base to move the auxiliary wheel between a plurality of auxiliary support positions including a deployed position and a stowed position. XLV. The patient transport device of paragraph XLIV, further comprising a locking member disposed on one of the base and the axle assembly, the locking member positioned against the other of the base and the axle assembly to define a range of movement of the axle assembly toward the base when the auxiliary wheels are in the stowed position. XLVI. The override assembly further comprises a cam member disposed between the base and the axle assembly, the cam member operably attached to the axle assembly for moving the axle assembly relative to the base, the cam member a cam-down position in which the auxiliary wheels are in a stowed position; a cam raised position in which the cam member moves the auxiliary wheels to the deployed position; 4. The patient transport device of clause XLIV or XLV, configured to move between a plurality of cam positions, including: XLVII. The patient transport device of clause XLVI, wherein the auxiliary wheel assembly further comprises a roller coupled to the axle assembly and disposed between the axle assembly and the cam member, the roller configured to abut the cam member and rotate to enable the cam member to move between a plurality of cam positions. XLVIII. The cam member defines a plurality of detents configured to engage the rollers to retain the cam member in the corresponding cam position, the plurality of detents comprising: a cam down detent for retaining the cam member in the cam down position; a cam raise detent for retaining the cam member in the cam raised position; 4. The patient transport device of claim XLVII, comprising: XLIX. The patient transport device of clause XLVIII, wherein the plurality of detents further includes a cam intermediate detent disposed between the cam lowering detent and the cam raising detent for retaining the cam member at a cam intermediate position between the cam raised position and the cam lowered position. L. The patient transport device of clause XLIX, wherein when the cam member is in the intermediate cam position, the cam member moves the axle assembly to an intermediate position between the stowed position and the deployed position. LI. The patient transport device of any one of paragraphs XLVI to L, wherein the auxiliary wheel assembly is coupled to the base and further comprises a biasing member operably attached to the axle assembly, the biasing member configured to bias the axle assembly against the cam member. LII. The patient transport device of any one of paragraphs XLVI to LI, wherein the auxiliary wheel assembly further comprises a cam driver coupled to the cam member for simultaneous rotation therewith. LIII. The patient transport apparatus of clause LII, wherein the linkage is in a braking state when the braking system is in a braking state, and the brake input device is further configured to move the linkage between a neutral state and a steering state when the braking system is in a released state. LIV. The patient transport device of clause LIII, wherein the override assembly further comprises an override member coupled to and extending between the linkage and cam driver of the braking system, and simultaneously moving the cam member from the cam raised position to the cam lowered position when the linkage moves from the steering state to the braking state. LV. The patient transport device of clause LIV, wherein the actuator is operably attached to the cam driver to move the cam member between a plurality of cam positions. LVI. The actuator is configured to generate a torque about the actuator axis; the cam driver defines a slot extending between a first slot end and a second slot end; 10. The patient transport device of clause LV, wherein the auxiliary wheel assembly further includes an actuator drive member coupled to the actuator for co-rotation with the actuator about the actuator axis, the actuator drive member including a protrusion spaced from the actuator axis and disposed within a slot in the cam driver, the protrusion translating within the slot and abutting one of the first slot end and the second slot end to transmit motion from the actuator to move the cam member between the plurality of cam positions. LVII. The patient transport device of clause LVI, wherein the actuator is configured to generate torque to rotate the actuator drive member to abut a protrusion on the actuator drive member against the first slot end, thereby simultaneously rotating the actuator drive member and the cam driver to move the cam member toward the cam raised position. LVIII. The patient transport device of paragraphs LVI or LVII, wherein the actuator is configured to generate torque to rotate the actuator drive member to abut the protrusion of the actuator drive member against the second slot end, thereby simultaneously rotating the actuator drive member and the cam driver to move the cam member toward the cam-down position. LIX. A patient transport device as described in any one of clauses LVI to VLIII, wherein the slot of the cam driver extends along an arc between a first slot end and a second slot end, the arc being shaped to allow the protrusion to translate within the slot without abutting one of the first slot end and the second slot end in response to movement of the cam member due to operation of the override assembly. LX. The patient transport device of clause LIX, wherein the actuator is configured to, in response to movement of the cam member due to operation of the override assembly, move the cam member to prevent the protrusion from abutting one of the first slot end and the second slot end, and then move the actuator drive member to a home position. LXI. An electric braking assembly comprising: a drive member coupled to the linkage; a brake actuator coupled to the drive member and configured to move the drive member to a first position and a second position; and an electric braking assembly including: 20. The patient transport device of any one of clauses XXV to LX, wherein movement of the drive member to the first position causes the linkage to place the braking system in a braked state, and movement of the drive member to the second position causes the linkage to place the braking system in a released state. LXII. A user interface having an input device configured for user engagement; a controller disposed in electrical communication with the electric brake assembly and the user interface, the controller configured to drive the actuator in response to user engagement with an input device to move the brake system between a braked state and a released state; Furthermore, The patient transport device of clause LXI, wherein the controller is configured to operate the actuator to move the auxiliary wheels to a stowed position in response to the braking system being placed in a braking state. LXIII. The patient transport device of clause LXII, wherein the auxiliary wheel assembly further comprises an auxiliary wheel drive system comprising a motor operably attached to the auxiliary wheel and configured to generate torque to rotate the auxiliary wheel. LXIV. The patient transport device of any one of clauses XXV to LXIII, further comprising a spring cartridge disposed between the support structure and the auxiliary wheels to bias the auxiliary wheels toward the deployed position and to allow the auxiliary wheels to deflect in response to engagement with an uneven floor surface. LXV.Brake input device a shaft operatively attached to the linkage of the braking system for simultaneous movement with the linkage; a shaft driver coupled to the shaft for simultaneous rotation therewith, the shaft driver defining a shaft driver slot extending between a slot brake end and a slot neutral end; a pedal operably mounted on the shaft for pivotal movement relative to the shaft, the pedal including a pedal projection spaced from the shaft and disposed within the shaft driver slot, the pedal projection translating within the shaft driver slot and abutting one of the slot brake end and the slot neutral end to transfer motion from the pedal to the shaft; 20. The patient transport device of any one of clauses XXV to LXIV, further comprising: LXVI. The patient transport device of clause LXV, wherein the pedal lug is configured to orbit about the shaft in a first direction in response to a user engaging a first side of the pedal to abut the pedal lug against the slot brake end and simultaneously rotating the pedal and shaft driver to move the linkage to a braking state. LXVII. The patient transport device of clause LXVI, wherein the pedal lug is configured to orbit around the shaft in a second direction opposite the first direction in response to a user engaging a second side of the pedal opposite the first side to abut the pedal lug against a slot neutral end and simultaneously rotating the pedal and shaft driver to move the linkage to a neutral state. LXVIII. The patient transport apparatus of any one of clauses LXV to LXVII, wherein the brake input device further comprises a brake input biasing member configured to bias the pedal projection of the pedal toward the slot brake end. LXIX. The override assembly further comprises a cam assembly operably attached to the axle assembly for moving the axle assembly relative to the base, the cam assembly comprising: a cam-down position in which the auxiliary wheels are in a stowed position; a cam raised position in which the cam assembly moves the auxiliary wheels to a deployed position; 4. The patient transport device of any one of clauses XLIV to LXVIII, configured to move between a plurality of cam positions, including: LXX. The patient transport device of clause LXIX, wherein the cam assembly includes a connecting link operably attached to the axle assembly, an intermediate link coupled to the connecting link for pivotal movement relative to the connecting link, and a cam member coupled to the intermediate link, the connecting link and the intermediate link configured to pivot relative to one another in response to rotation of the cam member to extend the cam assembly between a cam lowered position and a cam raised position. LXXI. The patient transport apparatus of clause LXX, wherein the intermediate link includes a first locking portion configured to abut the cam member and define a range of rotation of the intermediate link relative to the cam member. LXXII. The patient transport device of clause LXX or LXXI, wherein the connecting link includes a second locking portion configured to abut the intermediate link and define a range of rotation of the connecting link relative to the intermediate link. LXXIII. The patient transport device of any one of clauses LXX to LXXII, wherein the connecting link includes a third locking portion configured to abut the axle assembly and define a range of rotation of the connecting link relative to the axle assembly. LXXIV. The patient transport device of any one of clauses LXX to LXXIII, wherein the auxiliary wheel assembly further comprises a roller arm extending between a first roller arm end portion operably attached to the base for pivotal movement relative to the base and a second roller arm end portion, the roller arm including a roller configured to abut the cam member and rotate to enable the cam assembly to move between a cam-down position and a cam-up position. LXXV. The patient transport device of clause LXXIV, wherein the auxiliary wheel assembly further comprises a roller arm bias member extending between one of the first roller arm end portion and the second roller arm end portion and the axle assembly, urging the roller against the cam member and urging the axle assembly to move the auxiliary wheel toward the stowed position. LXXVI. The patient transport device of clause LXXV, wherein the auxiliary wheel assembly further comprises a roller arm damper extending between one of the first roller arm end portion and the second roller arm end portion and the base, damping movement of the roller arm relative to the base. LXXVII. The patient transport device of clause LXXV or LXXVI, wherein the auxiliary wheel assembly further comprises a cam damper extending between the cam member and the base and damping movement of the cam member relative to the base. LXXVIII. The cam member defines a plurality of detents configured to engage the rollers to retain the cam assembly in a corresponding cam position, the plurality of detents comprising: a cam down detent for retaining the cam assembly in the cam down position; a cam raise detent for retaining the cam assembly in the cam raised position; 10. The patient carrier of claim 9, further comprising: LXXIX. The patient transport device of clause LXXVIII, wherein the plurality of detents further includes a cam intermediate detent disposed between the cam lowering detent and the cam raising detent for retaining the cam assembly at a cam intermediate position between the cam raised position and the cam lowered position. LXXX. The patient transport device of clause LXXIX, wherein when the cam assembly is in the cam intermediate position, the roller arm bias member biases the axle assembly to move the auxiliary wheels to the stowed position. LXXXI. The patient transport apparatus of any one of clauses LXX to LXXX, wherein the linkage is in a braking state when the braking system is in a braking state, and the brake input device is further configured to move the linkage between a neutral state and a steering state when the braking system is in a released state. LXXXII. The patient transport device of clause LXXXI, further comprising an override assembly operably attached to the linkage of the braking system and the cam member, and configured to simultaneously move the cam assembly from the cam-up position to the cam-down position when the linkage moves from the steering state to the braking state. LXXXIII. The patient transport device of clause LXXXII, wherein the override assembly further comprises a linkage damper operably attached to the linkage and the base, damping movement of the linkage relative to the base. LXXXIV. The patient transport device of clause LXXXII or LXXXIII, wherein the auxiliary wheel assembly further comprises a cam driver coupled to the cam member for simultaneous rotation therewith. LXXXV. The patient transport device of clause LXXXIV, wherein the actuator is operably attached to the cam driver to move the cam assembly between a plurality of cam positions. LXXXVI. The actuator is configured to generate a torque about the actuator axis; The auxiliary wheel assembly further includes an actuator drive member coupled to the actuator for co-rotation with the actuator about the actuator axis, the actuator drive member defining a slot extending between a first slot end and a second slot end; The patient transport device of clause LXXXV, wherein the cam driver includes a protrusion spaced from the actuator shaft and disposed within a slot in the actuator drive member, the protrusion translating within the slot and abutting one of the first slot end and the second slot end to transfer motion from the actuator to the cam member to move the cam assembly between the plurality of cam positions. LXXXVII. The patient transport device of Clause LXXXVI, wherein the actuator is configured to generate torque to rotate the actuator drive member to abut the protrusion of the cam driver against the first slot end, thereby simultaneously rotating the actuator drive member and the cam driver to move the cam member, moving the cam assembly to the cam raised position, and moving the linkage to the steering state. LXXXVIII. The patient transport device of clause LXXXVII, wherein the actuator is configured to generate torque to rotate the actuator drive member to abut the protrusion of the cam driver against the second slot end, thereby simultaneously rotating the actuator drive member and the cam driver to move the cam member, moving the cam assembly toward the cam-down position, and moving the linkage to one of a neutral state and a brake state. LXXXIX. The patient transport device of clause LXXXVIII, wherein the slot of the actuator drive member extends along an arc between a first slot end and a second slot end, the arc being shaped to allow the protrusion to translate within the slot without abutting one of the first slot end and the second slot end in response to movement of the cam member due to operation of the override assembly. XC. The patient transport device of clause LXXXIX, wherein the actuator is configured to, in response to movement of the cam member due to operation of the override assembly, move the cam member to prevent the protrusion from abutting one of the first slot end and the second slot end, and then move the actuator drive member to a home position. XCI. The patient transport device of clause LXXXIX or XC, wherein the override assembly further comprises an actuator drive member position sensor configured to detect an angular position of the actuator drive member, and wherein the patient transport device is configured to operate the actuator based on the sensed position of the actuator drive member. XCII. The patient transport device of any one of clauses LXXXIX to XCI, wherein the override assembly further comprises a cam member position sensor configured to detect an angular position of the cam member, and the patient transport device is configured to operate the actuator based on the detected position of the cam member. XCIII. The brake input device further comprises a first pedal coupled to the linkage of the braking system for simultaneous movement with the linkage, the first pedal moving the linkage of the braking system in a first direction: a first pedal steering position in which the link mechanism is in a steering state; a first pedal neutral position in which the first pedal moves the linkage to a neutral state in a first direction; a first pedal braking position in which the first pedal moves the linkage in a first direction to a braking state; 10. The patient transport device of any one of clauses LXXXIX to XCII, configured for user engagement to move the patient transport device between XCIV. The patient transport device of clause XCIII, further comprising a second pedal assembly coupled to the linkage of the braking system and configured for user engagement to move the linkage of the braking system in a second direction opposite the first direction. XCV. The second pedal assembly is a second pedal mount extending from the base; a second pedal extending between a second pedal interface configured for user engagement and a second pedal connection end, the second pedal being mounted to a second pedal mount between the second pedal interface and the second pedal connection end and supported for rotation relative to the second pedal mount; a second pedal drive link coupled to the second pedal connection end for rotation relative to the second pedal connection end, the second pedal drive link defining a second pedal drive link slot extending between a first pedal slot end and a second pedal slot end, the braking system linkage including a linkage protrusion disposed within the second pedal drive link slot for movement within the second pedal drive link slot, the first pedal slot end configured to abut the linkage protrusion in response to user engagement with the second pedal interface to transfer motion from the second pedal to the braking system linkage and move the linkage in a second direction; 10. The patient transport device of claim XCIV, comprising: XCVI. The patient transport apparatus of clause XCV, wherein the brake input device further comprises a second pedal biasing member configured to urge the second pedal interface upward to abut the second pedal slot end against the linkage protrusion when there is no user engagement with the second pedal interface. XCVII. The patient transport device of clause XCVI, wherein when the linkage is in a braking state, the second pedal interface is in a second pedal braking position and is configured for user engagement to move the second pedal drive link such that the first pedal slot end abuts the linkage protrusion to move the linkage in a second direction from the braking state to a neutral state.

Claims

1. 1. A patient transport device, comprising: a support structure comprising a base and a patient support deck; a plurality of wheels coupled to the base for supporting movement of the patient transport device across a floor surface; a braking system including a linkage coupled to one or more of the plurality of wheels; a braking state that prevents movement of the base along the floor surface; The liberated state and a braking system operable between a brake input device in communication with the linkage and configured for user engagement to change operation of the braking system between the braking state and the released state, the linkage being in a braking state when the braking system is in the braking state, the brake input device further configured to move the linkage between a neutral state and a steering state in which the braking system is in the released state; an auxiliary wheel assembly comprising: an auxiliary wheel; an axle assembly coupled to the base for pivotal movement relative to the base and supporting the auxiliary wheel; and an actuator configured to move the axle assembly and the auxiliary wheel between a plurality of auxiliary support positions, the plurality of auxiliary support positions comprising: a deployed position, wherein the auxiliary wheels engage the floor surface to at least partially support movement of the patient transport device across the floor surface; and a storage position in which the auxiliary wheels are spaced apart from the floor surface; an auxiliary wheel assembly including: an override assembly coupled to the linkage of the braking system and to the auxiliary wheel assembly, the override assembly responsive to movement of the linkage from the steering state toward one of the neutral state and the braking state to move the auxiliary wheels from the deployed position to the stowed position and at least partially disengage the auxiliary wheels from the floor surface; A patient transport device comprising:

2. The override assembly further comprises a cam assembly operably attached to the axle assembly for moving the axle assembly relative to the base, the cam assembly comprising: a cam down position in which the auxiliary wheel is in the stored position; a cam raised position in which the cam assembly moves the auxiliary wheels to the deployed position; 10. The patient transport device of claim 1, configured to move between a plurality of cam positions, including:

3. 3. The patient transport apparatus of claim 2, wherein the cam assembly comprises a connecting link operatively attached to the axle assembly, an intermediate link coupled to the connecting link for pivotal movement relative to the connecting link, and a cam member coupled to the intermediate link, the connecting link and the intermediate link configured to pivot relative to one another in response to rotation of the cam member to extend the cam assembly between the cam lowered position and the cam raised position.

4. 4. The patient transport device of claim 3, wherein the auxiliary wheel assembly further comprises a roller arm extending between a first roller arm end portion operably attached to the base for pivotal movement relative to the base and a second roller arm end portion, the roller arm including a roller configured to abut the cam member and rotate to enable the cam assembly to move between the plurality of cam positions.

5. 5. The patient transport apparatus of claim 4, wherein the auxiliary wheel assembly further comprises a roller arm bias member extending between one of the first and second roller arm end portions and the axle assembly, the roller bias member biasing the roller against the cam member and biasing the axle assembly to move the auxiliary wheel toward the stowed position.

6. The patient transport device of claim 5 , wherein the auxiliary wheel assembly further comprises a cam damper extending between the cam member and the base to damp movement of the cam member relative to the base.

7. The cam member defines a plurality of detents configured to engage the roller to retain the cam assembly in a corresponding cam position, the plurality of detents comprising: a cam down detent for retaining said cam assembly in said cam down position; a cam raise detent for retaining the cam assembly in the cam raised position; The patient carrier of claim 5 , comprising:

8. 8. The patient transport apparatus of claim 7, wherein the plurality of detents further includes a cam intermediate detent disposed between the cam lowering detent and the cam raising detent for retaining the cam assembly at a cam intermediate position between the cam raised position and the cam lowered position.

9. 9. The patient transport device of claim 8, wherein when the cam assembly is in the cam intermediate position, the roller arm biasing member biases the axle assembly to move the auxiliary wheels to the stowed position.

10. 10. The patient transport apparatus of claim 9, further comprising an override assembly operably attached to the linkage of the braking system and the cam member, the override member simultaneously moving the cam assembly between the cam-raised position and the cam-lowered position as the linkage moves between the steering state and the braking state.

11. The patient transport apparatus of claim 10 , wherein the override assembly further comprises a linkage damper operably attached to the linkage and the base, the linkage damper damping movement of the linkage relative to the base.

12. The patient transport apparatus of claim 10 , wherein the auxiliary wheel assembly further comprises a cam driver coupled to the cam member for simultaneous rotation therewith.

13. The patient transport apparatus of claim 12 , wherein the actuator is operably attached to the cam driver to move the cam assembly between the plurality of cam positions.

14. the actuator is configured to generate a torque about an actuator axis; the auxiliary wheel assembly further comprising an actuator drive member coupled to the actuator for co-rotation with the actuator about the actuator axis, the actuator drive member defining a slot extending between a first slot end and a second slot end; 14. The patient transport apparatus of claim 13, wherein the cam driver includes a protrusion spaced from the actuator shaft and disposed within the slot of the actuator drive member, the protrusion translating within the slot and abutting one of the first slot end and the second slot end to transfer motion from the actuator to the cam member to move the cam assembly between a plurality of cam positions.

15. the actuator is configured to generate torque to rotate the actuator drive member to abut the protrusion of the cam driver against the first slot end, thereby simultaneously rotating the actuator drive member and the cam driver to move the cam member, moving the cam assembly to the cam raised position, and moving the linkage to the steering state; 15. The patient transport apparatus of claim 14, wherein the actuator is configured to generate torque to rotate the actuator drive member to abut the protrusion of the cam driver against the second slot end, thereby simultaneously rotating the actuator drive member and the cam driver to move the cam member, move the cam assembly toward the cam down position, and move the linkage to one of the neutral state and the braked state.

16. 16. The patient transport apparatus of claim 15, wherein the slot in the actuator drive member extends along an arc between the first slot end and the second slot end, the arc being shaped to allow the protrusion to translate within the slot without abutting one of the first slot end and the second slot end in response to movement of the cam member due to operation of the override assembly.

17. 17. The patient transport apparatus of claim 16, wherein the actuator is configured to, in response to movement of the cam member due to operation of the override assembly, move the cam member to prevent the protrusion from abutting one of the first slot end and the second slot end, and then move the actuator drive member to a home position.

18. 17. The patient transport apparatus of claim 16, wherein the override assembly further comprises an actuator drive member position sensor configured to detect an angular position of the actuator drive member, the patient transport apparatus configured to operate the actuator based on the sensed position of the actuator drive member.

19. 17. The patient transport apparatus of claim 16, wherein the override assembly further comprises a cam member position sensor configured to detect an angular position of the cam member, the patient transport apparatus configured to operate the actuator based on the sensed position of the cam member.

20. The brake input device further comprises a first pedal coupled to the linkage of the braking system for simultaneous movement therewith, the first pedal moving the linkage of the braking system in a first direction: a first pedal steering position in which the link mechanism is in the steering state; a first pedal neutral position in which the first pedal moves the linkage in the first direction to the neutral state; a first pedal braking position in which the first pedal moves the linkage in the first direction to the braking state; 17. The patient transport device of claim 16, configured for user engagement to move the patient between

21. 21. The patient transport apparatus of claim 20, further comprising a second pedal assembly coupled to the linkage of the braking system and configured for user engagement to move the linkage of the braking system in a second direction opposite the first direction.

22. The second pedal assembly includes: a second pedal mount extending from the base; a second pedal extending between a second pedal interface configured for user engagement and a second pedal connection end, the second pedal being attached to the second pedal mount between the second pedal interface and the second pedal connection end and supported for rotation relative to the second pedal mount; a second pedal drive link coupled to the second pedal connection end for rotation relative to the second pedal connection end, the second pedal drive link defining a second pedal drive link slot extending between a first pedal slot end and a second pedal slot end, the linkage of the braking system including a linkage protrusion disposed within the second pedal drive link slot for movement within the second pedal drive link slot, the first pedal slot end configured to abut the linkage protrusion in response to user engagement with the second pedal interface to transfer motion from the second pedal to the linkage of the braking system and move the linkage in the second direction; 22. The patient carrier of claim 21, comprising:

23. 23. The patient transport apparatus of claim 22, wherein the brake input device further comprises a second pedal biasing member configured to bias the second pedal interface upwardly to abut the second pedal slot end against the linkage protrusion in the absence of user engagement with the second pedal interface.

24. 24. The patient transport apparatus of claim 23, wherein when the linkage is in the braking state, the second pedal interface is in a second pedal braking position and is configured for user engagement to move the second pedal drive linkage such that the first pedal slot end abuts the linkage protrusion to move the linkage in the second direction from the braking state to the neutral state.

25. 1. A patient transport device, comprising: a support structure comprising a base and a patient support deck; a plurality of wheels coupled to the base for supporting movement of the patient transport device across a floor surface; a braking system including a linkage coupled to one or more of the plurality of wheels; a braking state that prevents movement of the base along the floor surface; The liberated state and a braking system operable between a brake input device in communication with the linkage and configured for user engagement to change operation of the braking system between the braked state and the released state; an auxiliary wheel assembly coupled to the support structure, the auxiliary wheel comprising: an actuator configured to move the auxiliary wheel between a plurality of auxiliary support positions, the plurality of auxiliary support positions comprising: a deployed position, wherein the auxiliary wheels engage the floor surface to at least partially support movement of the patient transport device across the floor surface; and a storage position in which the auxiliary wheels are spaced apart from the floor surface; an auxiliary wheel assembly including: an override assembly coupled to the linkage of the braking system and to the auxiliary wheel assembly for moving the auxiliary wheels away from the deployed position toward the stowed position in response to movement of the braking system from the released state toward the braked state; preventing movement of the base along the floor surface in the braking condition; and at least partially disengaging the auxiliary wheels from the floor surface; At the same time, override assembly and A patient transport device comprising:

26. 26. The patient transport device of claim 25, wherein the auxiliary wheel assembly further comprises an auxiliary frame coupled to the base, the auxiliary wheel and the actuator operably attached to the auxiliary frame.

27. The auxiliary frame is a first auxiliary rail extending longitudinally along the patient transport device and coupled to a first base rail of the base; a second auxiliary rail extending longitudinally along the patient carrier and coupled to a second base rail of the base; a first cross member extending between the first auxiliary rail and the second auxiliary rail at a first end of the auxiliary wheel assembly; a second cross member extending between the first auxiliary rail and the second auxiliary rail at a second end of the auxiliary wheel assembly; 27. The patient carrier of claim 26, comprising:

28. 28. The patient transport device of claim 27, wherein the auxiliary wheel assembly further comprises an axle assembly supporting the auxiliary wheels, the axle assembly operably attached to the first cross member for pivotal movement relative to the first cross member to move the auxiliary wheels between the plurality of auxiliary support positions, including the deployed position and the stowed position.

29. 30. The patient transport device of claim 28, wherein the actuator is coupled to the axle assembly at a first actuator end and operably attached to the second cross-member at a second actuator end, and configured to move the axle assembly to move the auxiliary wheels between the deployed position and the stowed position.

30. The axle assembly includes: a first axle subassembly rotatably supporting the auxiliary wheel, the first axle subassembly being operably mounted to the first equipment for pivotal movement relative to the first cross-member; a second axle subassembly operably mounted to the first axle subassembly and the first cross member for pivotal movement relative to the first cross member, the first actuator end being coupled to the second axle subassembly for moving the axle assembly to move the auxiliary wheels between the deployed position and the stowed position; 30. The patient carrier of claim 29, further comprising:

31. 31. The patient transport device of claim 30, further comprising a first spring cartridge disposed between the first axle subassembly and the first cross-member, biasing the axle assembly toward the deployed position and allowing the axle assembly to deflect toward the stowed position in response to engagement of the auxiliary wheel with an uneven floor surface.

32. 31. The patient transport apparatus of claim 30, further comprising a second spring cartridge disposed between the second axle subassembly and the first axle subassembly, the second spring cartridge enabling the second axle subassembly to deflect relative to the first axle subassembly in response to engagement of the auxiliary wheel with an uneven floor surface.

33. 31. The patient transport device of claim 30, wherein the first cross-member further comprises a first pair of brackets extending longitudinally from a first end of the first cross-member and a second pair of brackets extending longitudinally from a second end of the first cross-member, the first pair of brackets and the second pair of brackets defining a coaxial bore that defines a pivot axis.

34. 34. The patient transport apparatus of claim 33, wherein the first axle subassembly is coupled to the first and second pair of brackets via one or more shafts disposed within the coaxial bore for pivotal movement about the pivot axis.

35. 34. The patient transport apparatus of claim 33, wherein the second axle subassembly is coupled to the first and second pair of brackets via a shaft disposed within the coaxial bore for pivotal movement about the pivot axis.

36. the auxiliary wheel assembly further comprises an axle assembly supporting the auxiliary wheel, the axle assembly coupled to the auxiliary frame for pivotal movement relative to the auxiliary frame to move the auxiliary wheel between the plurality of auxiliary support positions, including the deployed position and the stowed position; 27. The patient transport device of claim 26, wherein the actuator is coupled to the axle assembly at a first actuator end and operably attached to the auxiliary frame at a second actuator end, and configured to move the axle assembly to move the auxiliary wheels between the deployed position and the stowed position.

37. The override assembly includes: a carriage extending longitudinally between a first carriage end spaced from the auxiliary frame and a second carriage end coupled to the auxiliary frame; a second actuator end coupled to the actuator and engaging the carriage; an operating position, the second actuator end being fixed in a spaced apart relationship at a first distance from the auxiliary frame to support the actuator for moving the auxiliary wheel between the deployed position and the stowed position; an override position, wherein the second actuator end is fixed in a spaced apart relationship to move the actuator to at least partially disengage the auxiliary wheel from the floor surface at a second distance from the auxiliary frame that is less than the first distance; a trolley for guiding movement of the second actuator end along the carriage between 37. The patient carrier of claim 36, further comprising:

38. The override assembly further includes an override linkage coupled to and disposed between the auxiliary frame and the second actuator end, the override linkage comprising: an extended state in which the override linkage moves the second actuator end to the operating position; a folded state in which the override linkage moves the second actuator end to the override position; 38. The patient transport device of claim 37, configured to move between

39. 39. The patient transport apparatus of claim 38, wherein the linkage is in a braking state when the braking system is in the braking state, and the brake input device is further configured to move the linkage between a neutral state and a steering state when the braking system is in the released state.

40. 40. The patient transport device of claim 39, wherein the override assembly further comprises an override member coupled to and extending between the braking system linkage and the override linkage, the override member simultaneously moving the override linkage from the extended state to the folded state as the linkage moves from the steering state to the braking state.

41. The override link mechanism is a first link including a first link mounting end coupled to the second actuator end for pivotal movement relative to the second actuator end and a first link pivot end; a second link including a second link mounting end coupled to the sub-frame for pivotal movement relative to the sub-frame and a second link pivot end coupled to the first link pivot end for pivotal movement relative to the first link pivot end; 40. The patient carrier of claim 39, comprising:

42. 42. The patient transport device of claim 41, wherein the override assembly further comprises an override member coupled to and extending between the linkage and one of the first link pivot end and the second link pivot end of the braking system, the override member simultaneously moving the override linkage from the extended state to the folded state as the linkage moves from the steering state to the braking state.

43. The linkage of the braking system comprises: a hexagonal shaft that rotates in response to movement of the linkage between the braking state and the steering state; a pivot arm extending from the hexagonal shaft and coupled to the override member, the pivot arm converting rotation of the hexagonal shaft into translation of the override member to simultaneously move the override linkage from the extended state to the folded state as the linkage moves from the steering state to the braking state; 43. The patient carrier of claim 42, comprising:

44. 26. The patient transport device of claim 25, wherein the auxiliary wheel assembly further comprises an axle assembly supporting the auxiliary wheels, the axle assembly coupled to the base for pivotal movement relative to the base to move the auxiliary wheels between the plurality of auxiliary support positions, including the deployed position and the stowed position.

45. 45. The patient transport device of claim 44, further comprising a locking member disposed on one of the base and the axle assembly, the locking member positioned against the other of the base and the axle assembly to define a range of movement of the axle assembly toward the base when the auxiliary wheels are in the stowed position.

46. The override assembly further comprises a cam member disposed between the base and the axle assembly, the cam member operably attached to the axle assembly for moving the axle assembly relative to the base, the cam member comprising: a cam down position in which the auxiliary wheel is in the stored position; a cam raised position in which the cam member moves the auxiliary wheels to the deployed position; 45. The patient transport device of claim 44, configured to move between a plurality of cam positions, including:

47. 47. The patient transport apparatus of claim 46, wherein the auxiliary wheel assembly further comprises a roller coupled to the axle assembly and disposed between the axle assembly and the cam member, the roller configured to abut the cam member and rotate to enable the cam member to move between the plurality of cam positions.

48. The cam member defines a plurality of detents configured to engage the roller to retain the cam member in a corresponding cam position, the plurality of detents comprising: a cam down detent for retaining said cam member in said cam down position; a cam raise detent for retaining said cam member in said cam raised position; 48. The patient carrier of claim 47, comprising:

49. 49. The patient transport apparatus of claim 48, wherein the plurality of detents further includes a cam intermediate detent disposed between the cam lowering detent and the cam raising detent for retaining the cam member at a cam intermediate position between the cam raised position and the cam lowered position.

50. 50. The patient transport apparatus of claim 49, wherein when the cam member is in the cam intermediate position, the cam member moves the axle assembly to an intermediate position between the stowed position and the deployed position.

51. 47. The patient transport apparatus of claim 46, wherein the auxiliary wheel assembly is coupled to the base and further comprises a biasing member operably attached to the axle assembly, the biasing member configured to bias the axle assembly against the cam member.

52. 47. The patient transport apparatus of claim 46, wherein the auxiliary wheel assembly further comprises a cam driver coupled to the cam member for simultaneous rotation therewith.

53. 53. The patient transport apparatus of claim 52, wherein the linkage is in a braking state when the braking system is in the braking state, and the brake input device is further configured to move the linkage between a neutral state and a steering state when the braking system is in the released state.

54. 54. The patient transport apparatus of claim 53, wherein the override assembly further comprises an override member coupled to and extending between the braking system linkage and the cam driver, the override member simultaneously moving the cam member from the cam raised position to the cam lowered position when the linkage moves from the steering state to the braking state.

55. 55. The patient transport apparatus of claim 54, wherein the actuator is operably attached to the cam driver to move the cam member between the plurality of cam positions.

56. the actuator is configured to generate a torque about an actuator axis; the cam driver defines a slot extending between a first slot end and a second slot end; 56. The patient transport apparatus of claim 55, wherein the auxiliary wheel assembly further comprises an actuator drive member coupled to the actuator for co-rotation with the actuator about the actuator axis, the actuator drive member including a protrusion spaced from the actuator axis and disposed within the slot of the cam driver, the protrusion translating within the slot and abutting one of the first slot end and the second slot end to transfer motion from the actuator to move the cam member between the plurality of cam positions.

57. 57. The patient transport apparatus of claim 56, wherein the actuator is configured to generate torque to rotate the actuator drive member to abut a protrusion on the actuator drive member against the first slot end, thereby simultaneously rotating the actuator drive member and the cam driver to move the cam member toward the cam raised position.

58. 57. The patient transport apparatus of claim 56, wherein the actuator is configured to generate torque to rotate the actuator drive member to abut a protrusion on the actuator drive member against the second slot end, thereby simultaneously rotating the actuator drive member and the cam driver to move the cam member toward the cam lowered position.

59. 57. The patient transport apparatus of claim 56, wherein the slot of the cam driver extends along an arc between the first slot end and the second slot end, the arc being shaped to allow the protrusion to translate within the slot without abutting one of the first slot end and the second slot end in response to movement of the cam member due to operation of the override assembly.

60. 60. The patient transport apparatus of claim 59, wherein the actuator is configured to, in response to movement of the cam member due to operation of the override assembly, move the cam member to prevent the protrusion from abutting one of the first slot end and the second slot end, and then move the actuator drive member to a home position.

61. 1. An electric braking assembly comprising: a drive member coupled to the link mechanism; a brake actuator coupled to the drive member and configured to move the drive member to a first position and a second position; and an electric braking assembly including:

26. The patient transport apparatus of claim 25, wherein movement of the drive member to the first position causes the linkage to place the braking system in the braked state, and movement of the drive member to the second position causes the linkage to place the braking system in the released state.

62. a user interface having an input device configured for user engagement; a controller disposed in electrical communication with the electric brake assembly and the user interface, the controller configured to actuate the actuator in response to user engagement with the input device to move the brake system between the braked state and the released state; and Furthermore, 62. The patient transport apparatus of claim 61, wherein the controller is configured to operate the actuator to move the auxiliary wheels toward the storage member in response to the braking system being placed in the braking state.

63. 63. The patient transport device of claim 62, wherein the auxiliary wheel assembly further comprises an auxiliary wheel drive system comprising a motor operably attached to the auxiliary wheel and configured to generate torque to rotate the auxiliary wheel.

64. 26. The patient transport device of claim 25, further comprising a spring cartridge disposed between the support structure and the auxiliary wheels, biasing the auxiliary wheels toward the deployed position and allowing the auxiliary wheels to deflect in response to engagement with an uneven floor surface.

65. The brake input device a shaft operatively attached to the linkage of the braking system for simultaneous movement therewith; a shaft driver coupled to the shaft for simultaneous rotation therewith, the shaft driver defining a shaft driver slot extending between a slot brake end and a slot neutral end; a pedal operably mounted on the shaft for pivotal movement relative to the shaft, the pedal including a pedal protrusion spaced from the shaft and disposed within the shaft driver slot, the pedal protrusion translating within the shaft driver slot and abutting one of the slot brake end and the slot neutral end to transfer motion from the pedal to the shaft; 26. The patient carrier of claim 25, further comprising:

66. 66. The patient transport device of claim 65, wherein the pedal lug is configured to orbit about the shaft in a first direction in response to a user engaging a first side of the pedal to abut the pedal lug against the slot brake end and simultaneously rotating the pedal and the shaft driver to move a linkage to the braking state.

67. 67. The patient transport device of claim 66, wherein the pedal lug is configured to orbit about the shaft in a second direction opposite the first direction in response to a user engaging a second side of the pedal opposite the first side to abut the pedal lug against the slot neutral end and simultaneously rotating the pedal and the shaft driver to move the linkage to a neutral state.

68. 66. The patient transport apparatus of claim 65, wherein the brake input device further comprises a brake input biasing member configured to bias the pedal projection of the pedal toward the slot brake end.

69. The override assembly further comprises a cam assembly operably attached to the axle assembly for moving the axle assembly relative to the base, the cam assembly comprising: a cam down position in which the auxiliary wheel is in the stored position; a cam raised position in which the cam assembly moves the auxiliary wheels to the deployed position; 45. The patient transport device of claim 44, configured to move between a plurality of cam positions, including:

70. 70. The patient transport apparatus of claim 69, wherein the cam assembly comprises a connecting link operably attached to the axle assembly, an intermediate link coupled to the connecting link for pivotal movement relative to the connecting link, and a cam member coupled to the intermediate link, the connecting link and the intermediate link configured to pivot relative to one another in response to rotation of the cam member to extend the cam assembly between the cam lowered position and the cam raised position.

71. 71. The patient transport apparatus of claim 70, wherein the intermediate link includes a first locking portion configured to abut the cam member and define a range of rotation of the intermediate link relative to the cam member.

72. 71. The patient transport apparatus of claim 70, wherein the connecting link includes a second locking portion configured to abut the intermediate link and define a range of rotation of the connecting link relative to the intermediate link.

73. 71. The patient transport apparatus of claim 70, wherein the coupling link includes a third locking portion configured to abut the axle assembly and define a range of rotation of the coupling link relative to the axle assembly.

74. 71. The patient transport apparatus of claim 70, wherein the auxiliary wheel assembly further comprises a roller arm extending between a first roller arm end portion operably attached to the base for pivotal movement relative to the base and a second roller arm end portion, the roller arm including a roller configured to abut the cam member and rotate to enable the cam assembly to move between the cam lowered position and the cam raised position.

75. 75. The patient transport apparatus of claim 74, wherein the auxiliary wheel assembly further comprises a roller arm bias member extending between one of the first and second roller arm end portions and the axle assembly, biasing the roller against the cam member and biasing the axle assembly to move the auxiliary wheel toward the stowed position.

76. 76. The patient transport apparatus of claim 75, wherein the auxiliary wheel assembly further comprises a roll arm damper extending between one of the first and second roll arm end portions and the base, the roll arm damper damping movement of the roll arm relative to the base.

77. 76. The patient transport apparatus of claim 75, wherein the auxiliary wheel assembly further comprises a cam damper extending between the cam member and the base to damp movement of the cam member relative to the base.

78. The cam member defines a plurality of detents configured to engage the roller to retain the cam assembly in a corresponding cam position, the plurality of detents comprising: a cam down detent for retaining said cam assembly in said cam down position; a cam raise detent for retaining the cam assembly in the cam raised position; 76. The patient carrier of claim 75, comprising:

79. 79. The patient transport apparatus of claim 78, wherein the plurality of detents further includes a cam intermediate detent disposed between the cam lowering detent and the cam raising detent for retaining the cam assembly at a cam intermediate position between the cam raised position and the cam lowered position.

80. 80. The patient transport apparatus of claim 79, wherein when the cam assembly is in the cam intermediate position, the roller arm biasing member biases the axle assembly to move the auxiliary wheels to the stowed position.

81. 71. The patient transport apparatus of claim 70, wherein the linkage is in a braking state when the braking system is in the braking state, and the brake input device is further configured to move the linkage between a neutral state and a steering state when the braking system is in the released state.

82. 82. The patient transport apparatus of claim 81, further comprising an override assembly operably attached to the linkage of the braking system and the cam member, the override member simultaneously moving the cam assembly from the cam raised position to the cam lowered position when the linkage moves from the steering state to the braking state.

83. 83. The patient transport apparatus of claim 82, wherein the override assembly further comprises a linkage damper operably attached to the linkage and the base, damping movement of the linkage relative to the base.

84. 83. The patient transport apparatus of claim 82, wherein the auxiliary wheel assembly further comprises a cam driver coupled to the cam member for simultaneous rotation therewith.

85. 85. The patient transport apparatus of claim 84, wherein the actuator is operably attached to the cam driver to move the cam assembly between the plurality of cam positions.

86. the actuator is configured to generate a torque about an actuator axis; the auxiliary wheel assembly further comprising an actuator drive member coupled to the actuator for co-rotation with the actuator about the actuator axis, the actuator drive member defining a slot extending between a first slot end and a second slot end; 86. The patient transport apparatus of claim 85, wherein the cam driver includes a protrusion spaced from the actuator shaft and disposed within the slot of the actuator drive member, the protrusion translating within the slot and abutting one of the first slot end and the second slot end to transfer motion from the actuator to the cam member and move the cam assembly between a plurality of cam positions.

87. 87. The patient transport apparatus of claim 86, wherein the actuator is configured to generate torque to rotate the actuator drive member to abut the protrusion of the cam driver against the first slot end, thereby simultaneously rotating the actuator drive member and the cam driver to move the cam member, moving the cam assembly to the cam raised position and moving the linkage to the steering state.

88. 88. The patient transport apparatus of claim 87, wherein the actuator is configured to generate torque to rotate the actuator drive member to abut the protrusion of the cam driver against the second slot end, thereby simultaneously rotating the actuator drive member and the cam driver to move the cam member, move the cam assembly toward the cam lowered position, and move the linkage to one of the neutral state and the braked state.

89. 89. The patient transport apparatus of claim 88, wherein the slot in the actuator drive member extends along an arc between the first slot end and the second slot end, the arc being shaped to allow the protrusion to translate within the slot without abutting one of the first slot end and the second slot end in response to movement of the cam member due to operation of the override assembly.

90. 90. The patient transport apparatus of claim 89, wherein the actuator is configured to, in response to movement of the cam member due to operation of the override assembly, move the cam member to prevent the protrusion from abutting one of the first slot end and the second slot end, and then move the actuator drive member to a home position.

91. 90. The patient transport apparatus of claim 89, wherein the override assembly further comprises an actuator drive member position sensor configured to detect an angular position of the actuator drive member, the patient transport apparatus configured to operate the actuator based on the sensed position of the actuator drive member.

92. 90. The patient transport apparatus of claim 89, wherein the override assembly further comprises a cam member position sensor configured to detect an angular position of the cam member, the patient transport apparatus configured to operate the actuator based on the sensed position of the cam member.

93. The brake input device further comprises a first pedal coupled to the linkage of the braking system for simultaneous movement therewith, the first pedal moving the linkage of the braking system in a first direction: a first pedal steering position in which the link mechanism is in the steering state; a first pedal neutral position in which the first pedal moves the linkage in the first direction to the neutral state; a first pedal braking position in which a first pedal moves the linkage in the first direction to the braking state; 90. The patient carry device of claim 89, configured for user engagement to move between

94. 94. The patient transport apparatus of claim 93, further comprising a second pedal assembly coupled to the linkage of the braking system and configured for user engagement to move the linkage of the braking system in a second direction opposite the first direction.

95. The second pedal assembly includes: a second pedal mount extending from the base; a second pedal extending between a second pedal interface configured for user engagement and a second pedal connection end, the second pedal being attached to the second pedal mount between the second pedal interface and the second pedal connection end and supported for rotation relative to the second pedal mount; a second pedal drive link coupled to the second pedal connection end for rotation relative to the second pedal connection end, the second pedal drive link defining a second pedal drive link slot extending between a first pedal slot end and a second pedal slot end, the linkage of the braking system including a linkage protrusion disposed within the second pedal drive link slot for movement within the second pedal drive link slot, the first pedal slot end configured to abut the linkage protrusion in response to user engagement with the second pedal interface to transfer motion from the second pedal to the linkage of the braking system and move the linkage in the second direction; 95. The patient carrier of claim 94, comprising:

96. 96. The patient transport apparatus of claim 95, wherein the brake input device further comprises a second pedal biasing member configured to bias the second pedal interface upward to abut the second pedal slot end against the linkage protrusion when there is no user engagement with the second pedal interface.

97. 97. The patient transport apparatus of claim 96, wherein when the linkage is in the braking state, the second pedal interface is in a second pedal braking position and is configured for user engagement to move the second pedal drive linkage such that the first pedal slot end abuts the linkage protrusion to move the linkage in the second direction from the braking state to the neutral state.

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