Powered caster drive system for a mobile medical device and patient transport apparatus including the same

Abstract

A powered caster drive system for facilitating movement of a mobile medical device along floor surfaces includes at least one powered caster assembly including a wheel, a wheel support arranged to support the wheel, and a steer lock assembly. The steer lock assembly is operable between a steer locked state that impedes swiveling of the wheel about a swivel axis, and a non- steer locked state. The at least one powered caster assembly also includes a hub motor interposed between the wheel and the wheel support. The caster drive system is operable between a first state to operate the hub motor to selectively modulate application of torque to the wheel during operation of the steer lock assembly in the steer locked state, and a second state operable to inhibit the hub motor from generating torque to drive the wheel during operation of the steer lock assembly in the non-steer locked state.

Description

POWERED CASTER DRIVE SYSTEM FOR A MOBILE MEDICAL DEVICE AND PATIENT TRANSPORT APPARATUS INCLUDING THE SAMECROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] The subject patent application claims priority to and all the benefits of United States Provisional Patent Application No. 63 / 558,256 filed on February 27, 2024, the disclosure of which is hereby incorporated by reference in its entirety.BACKGROUND

[0002] Traditionally, mobile medical devices (e.g., mobile medical imaging equipment, anesthesia equipment, respiratory equipment, crash carts, patient transport apparatuses, patient support apparatuses, patient lift / transfer devices, supply carts, and the like) typically have unpowered caster wheels, and thus require manual maneuvering by healthcare professionals, often necessitating significant physical effort. While providing the advantage of movement in multiple directions, these caster wheel arrangements pose a unique challenge when considering the implementation of powered systems. Given the multidirectional nature of caster wheels, they tend to have unpredictable directional control, making it difficult to implement a reliable and efficient power drive system. Consequently, there is an unmet need in the field for a power caster drive system that can seamlessly integrate with mobile medical devices, providing efficient, reliable, and safe movement.SUMMARY

[0003] One general aspect of the present disclosure is directed to a powered caster drive system for a mobile medical device for facilitating movement of the mobile medical device along a floor surface. The powered caster drive system includes at least one powered caster assembly.The at least one powered caster assembly includes a wheel for contacting the floor surface, a wheelsupport configured to be operatively attached to the mobile medical device and arranged to support the wheel for rotation about a rotational axis and for swiveling about a swivel axis, and a steer lock assembly. The steer lock assembly is operable between a steer locked state that impedes swiveling of the wheel about the swivel axis, and a non-steer locked state. The at least one powered caster assembly also includes a hub motor interposed between the wheel and the wheel support and configured to selectively modulate application of torque to the wheel to facilitate movement of the mobile medical device along the floor surface. The powered caster drive system also includes a controller in communication with the at least one powered caster assembly and configured to operate the powered caster drive system. The powered caster drive system is operable between a first state and a second state. In the first state, the powered caster drive system is operable to operate the hub motor to selectively modulate application of torque to the wheel of the at least one powered caster assembly during operation of the steer lock assembly in the steer locked state. In the second state, the powered caster drive system is operable to inhibit the hub motor from applying torque to drive the wheel of the at least one powered caster assembly during operation of the steer lock assembly in the non-steer locked state.

[0004] Another general aspect of the present disclosure includes a patient transport apparatus for transporting a patient. The patient transport apparatus includes a support structure. The support structure includes a base defining a head end and a foot end, and a patient support deck operatively attached to the base and defining a patient support surface to support the patient. The patient transport apparatus also includes a powered caster drive system. The powered caster drive system includes at least one powered caster assembly operatively attached to the base for facilitating movement of the support structure along a floor surface. The at least one powered caster assembly includes a wheel for contacting the floor surface, a wheel support operativelyattached to the base and arranged to support the wheel for rotation about a rotational axis and for swiveling about a swivel axis, and a steer lock assembly. The steer lock assembly is operable between a steer locked state that impedes swiveling of the wheel about the swivel axis, and a nonsteer locked state, and a hub motor interposed between the wheel and the wheel support and configured to selectively modulate application of torque to the wheel to facilitate movement of the support structure along the floor surface. The patient transport apparatus also includes a controller in communication with the powered caster drive system and configured to operate the powered caster drive system. The powered caster drive system is operable between a plurality of states including a first state and a second state. In the first state, the powered caster drive system is operable to operate the hub motor to selectively modulate application of torque to the wheel of the at least one powered caster assembly during operation of the steer lock assembly in the steer locked state. In the second state, the powered caster drive system is operable to inhibit the hub motor from applying torque to drive the wheel of the at least one powered caster assembly during operation of the steer lock assembly in the non-steer locked state.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 is a perspective view of a patient transport apparatus including a powered caster drive system with at least one powered caster assembly according to the present disclosure.

[0006] Figure 2A is a cross-sectional interior side view illustrating one of the powered caster assemblies in a neutral configuration in which a brake assembly is in an unbraked state and a steer lock assembly is in a non-steer locked state.

[0007] Figure 2B is a cross-sectional interior side view illustrating the powered caster assembly of Figure 2A in a configuration in which the brake assembly is in the unbraked state, and the steer lock assembly is in a steer locked state.

[0008] Figure 2C is a cross-sectional interior side view illustrating the powered caster assembly of Figure 2A in a configuration in which the brake assembly is in the braked state, and the steer lock assembly is in the non-steer locked state.

[0009] Figure 3A is a front schematic representation of one of the powered caster assemblies arranged with a camber offset.

[0010] Figure 3B is a top schematic representation of one of the powered caster assemblies arranged with a toe offset.

[0011] Figure 4 is an exploded representation of one of the powered caster assemblies.

[0012] Figure 5 is a schematic view of a control system according to the present disclosure.

[0013] Figure 6 is a perspective view of a handle including a first user input implemented as a throttle and a second user input implemented as a capacitive sensor.

[0014] Figure 7A is a cross-sectional interior side view illustrating one of the powered caster assemblies in a neutral configuration in which a brake assembly is in an unbraked state and a steer lock assembly is in a non-steer locked state, shown having a slip ring.

[0015] Figure 7B is another cross-sectional interior side view illustrating the powered caster assembly of Figure 7A in a configuration in which the brake assembly is in the unbraked state, and the steer lock assembly is in a steer locked state.

[0016] Figure 8A is a perspective view depicting portions of the slip ring of the caster assembly of Figures 7A-7B.

[0017] Figure 8B is an exploded perspective view of the portions of the slip ring of Figure 8A.

[0018] Figure 9 is an exploded perspective view of another version of the slip ring ofFigures 8A-8B.

[0019] Figure 10A is a cross-sectional interior side view illustrating one of the powered caster assemblies in a neutral configuration in which a brake assembly is in an unbraked state and a steer lock assembly is in a non-steer locked state, shown having a slip ring disposed in a separated ring configuration with one portion of the ring coupled to a steer lock pin, and with another portion of the ring coupled to an interface plate.

[0020] Figure 10B is another cross-sectional interior side view illustrating the powered caster assembly of Figure 10A in a configuration in which the brake assembly is in the unbraked state, and the steer lock assembly is in a steer locked state, shown with the slip ring disposed in an engaged ring configuration.

[0021] Figure 11A is a cross-sectional interior side view illustrating one of the powered caster assemblies in a neutral configuration in which a brake assembly is in an unbraked state and a steer lock assembly is in a non-steer locked state, shown having another type of slip ring.

[0022] Figure 11B is another cross-sectional interior side view illustrating the powered caster assembly of Figure 11 A in a configuration in which the brake assembly is in the unbraked state, and the steer lock assembly is in a steer locked state.

[0023] Figure 12A is a perspective view depicting portions of the slip ring of the caster assembly of Figures 11A-11B.

[0024] Figure 12B is an exploded perspective view of the portions of the slip ring of Figure 12A.DETAILED DESCRIPTION

[0025] Referring to Figure 1, a mobile medical device 28 is shown. In the illustrated configurations, the mobile medical device 28 is realized as a patient transport apparatus 30 for supporting a patient in a health care setting. The patient transport apparatus 30 may include ahospital bed, stretcher, cot, wheelchair, chair, or similar apparatus utilized in the care of a patient. In the configuration shown in Figure 1, the patient transport apparatus 30 includes a cot that is utilized to transport patients, such as from an emergency site to an emergency vehicle (e.g., an ambulance). It should be appreciated that the mobile medical device 28 may be realized as other devices in a healthcare setting which are typically on wheels, such as mobile medical imaging equipment, anesthesia equipment, respiratory equipment, crash carts, patient lift / transfer devices, supply carts, and the like. As will be appreciated from the subsequent description below, aspects of the patient transport apparatus 30 apply to other forms of mobile medical devices 28, and use of the terms “patient transport apparatus” and “mobile medical device” herein may be interchangeable.

[0026] The patient transport apparatus 30 shown in Figure 1 includes a support structure 32 that provides support for the patient. The support structure 32 includes a base 34. The base 34 may include a base frame 35. The support structure 32 may also include a support frame 36 that is spaced above the base frame 35. The support structure 32 also includes a patient support deck 38 operatively attached to the base 34 (e.g., disposed on the support frame 36). The patient support deck 38 may include several sections, some of which are capable of articulating relative to the support frame 36, such as a back section 41, a seat section 43, a leg section 45, and a foot section 47. The patient support deck 38 provides a patient support surface 42 upon which the patient is supported.

[0027] The base 34, support frame 36, patient support deck 38, and patient support surface 42 each have a head end HE and a foot end FE corresponding to designated placement of the patient’s head and feet on the patient transport apparatus 30. The patient transport apparatus 30 defines a longitudinal axis L along its length (i.e., extending between the head end HE to the footend FE). The patient transport apparatus 30 also includes a vertical axis V arranged crosswise (e.g., orthogonal) to the longitudinal axis L along which the patient support deck 38 may be lifted and lowered relative to the base 34 via a lift mechanism 37. The construction of the support structure 32 may take on any known or conventional design, and is not limited to that specifically set forth above. In addition, a mattress (not shown) may be provided in certain configurations, such that the patient rests directly on a patient support surface of the mattress while also being supported by the patient support surface 42.

[0028] Side rails 44, 46 may be coupled to the support frame 36 and thereby supported by the base 34. For example, a right side rail 44 may be positioned at a right side of the patient support deck 38, and a left side rail 46 may be positioned at a left side of the patient support deck 38 (with the left side defined relative to a person positioned at the head end HE of the patient support deck 38 and facing the patient support deck 38). If the patient transport apparatus 30 is a hospital bed, there may be more side rails. The side rails 44, 46 may be fixed relative to the support frame 36 or may be movable between a raised position in which they block ingress and egress into and out of the patient transport apparatus 30, one or more intermediate positions, and a lowered position in which they are not an obstacle to such ingress and egress. In still other configurations, the patient transport apparatus 30 may not include any side rails.

[0029] The present disclosure also includes a powered caster drive system 48 for facilitating movement of the mobile medical device 28 (e.g., the patient transport apparatus 30) along a floor surface F. The powered caster drive system 48 includes at least one powered caster assembly 49 configured to be operatively attached to the mobile medical device 28 (e.g., the base 34 of the patient transport apparatus 30) for facilitating movement of the mobile medical device28 along a floor surface F. Each of the at least one powered caster assembly 49 includes a wheel50 for contacting the floor surface. Each of the at least one powered caster assembly 49 further includes a wheel support 54. The wheel support 54 is configured to be operatively attached to the mobile medical device 28 (e.g., the base 34 of the patient transport apparatus 30) and arranged to support the wheel 50 for rotation about a rotational axis R and for swiveling about a swivel axis S (see Figures 1 and 4). The wheel support 54 may include various types of support structures for supporting the wheel 50 in such a manner. In the configuration shown, referring to Figure 4, the wheel support 54 includes a fork 56, a neck 58 fixed to the fork 56, and a stem 60. The neck 58 may be coupled to the stem 60 via a bearing 55 so that the neck 58 is able to swivel relative to the stem 60 about the swivel axis S when the wheel 50 is changing orientation. The wheel 50 may be operatively attached to the fork 56 via an axle 62 attached to the fork 56. In some examples, the axle 62 may be integral with the hub motor 72 (described below). Accordingly, the wheel 50 is arranged to rotate about the rotational axis R. The stem 60 is configured to be rotatably coupled to the mobile medical device 28 (e.g., the base 34 of the patient transport apparatus 30) for rotation about the swivel axis S.

[0030] In some examples, the wheel support 54 may be configured such that the swivel axis S is generally parallel to the vertical axis (i.e., orthogonal to the floor surface F and / or to the rotational axis R). Eikewise, in some examples, where the steer lock assembly 64 is in the steer locked state SL, the wheel 50 is arranged such that the rotational axis R is orthogonal to the longitudinal axis E and the steer lock assembly 64 impedes swiveling of the wheel 50 about the swivel axis S. It should be appreciated that in some configurations, there may be two positions where the wheel 50 is arranged such that the rotational axis R is orthogonal to the longitudinal axis L. For example, a wheel 50 may be in a “leading position” where the wheel 50 is arranged such that the rotational axis R is orthogonal to the longitudinal axis L and the fork extends toward thehead end HE. Conversely, a wheel 50 may be in a “lagging position” (or “trailing position”) where the wheel 50 is arranged such that the rotational axis R is orthogonal to the longitudinal axis L and the fork extends toward the foot end FE. In these examples, as will be appreciate in view of the description below, the hub motor 72 (and / or the control system 74) may adjust the direction of the torque applied to the wheel 50 based on whether the wheel 50 is in the leading position or the lagging position.

[0031] In some examples, the wheel support 54 may be configured such that the wheel(s) 50 have at least one of a camber offset and a toe offset. For example, referring to Figure 3A, to realize a camber offset of the wheel(s) 50, the swivel axis S may be angularly offset from parallel to the vertical axis V by a camber angle CA. Referring to FIG. 3B, to realize a toe offset of the wheel(s) 50, the wheel(s) 50 may be arranged such that the rotational axis R is angularly offset from orthogonal to the longitudinal axis L by a toe angle TA where a steer lock assembly 64 is in a steer locked state SL (described in further detail below) to impede swiveling of the wheel about the swivel axis S. By configuring the wheel support 54 such that the wheel(s) 50 have at least one of a camber offset and a toe offset, it can be assured that the output from the hub motor 72 (described below) produces a torque vector arranged inwards towards the mobile medical device 28 (e.g. the base 34 of the patient transport apparatus 30) to guide the mobile medical device 28 (e.g. the base 34 of the patient transport apparatus 30) along a straight path forward.

[0032] As shown for the patient transport apparatus 30 illustrated in Figure 1, it should be appreciated that additional wheels 51 may be coupled to the mobile medical device 28 (e.g., the base 34 of the patient transport apparatus 30) to facilitate transport of mobile medical device 28 over floor surfaces. For example, the additional wheels 51 may be arranged in each of four quadrants of the base 34 adjacent to comers of the base frame 35 where the powered caster drivesystem 48 is not included. In the configuration shown, the additional wheels 51 are unpowered caster wheels able to rotate and swivel relative to the support structure 32 during transport. Each of the additional wheels 51 forms part of an unpowered caster assembly 52. Each unpowered caster assembly 52 is mounted to the base 34. It should be understood that various configurations of the unpowered caster assemblies 52 are contemplated. In addition, in some configurations, the additional wheels 51 are not caster wheels and may be non-steerable, steerable, or combinations thereof.

[0033] Similar to as described above in the context of the at least one powered caster assembly 49, each of the unpowered caster assemblies 52 may further include a wheel support 54. The wheel support 54 is operatively attached to the mobile medical device 28 (e.g. the base 34 of the patient transport apparatus 30) and arranged to support the additional wheel 51 for rotation about a rotational axis R (see Figure 1) and for swiveling about a swivel axis S, with the swivel axis S generally normal to the floor surface F and to the rotational axis R. The wheel support 54 may include various types of support structures, similar to as described above. An exemplary wheel support 54 and exemplary configurations of an unpowered caster assembly 52 are disclosed in U.S. Patent No. 11,197,791, filed Nov. 21, 2019, the contents of which are hereby incorporated by reference in its entirety.

[0034] In some examples, the mobile medical device 28 (e.g., the patient transport apparatus 30) may include more than one powered caster assembly 49 for facilitating movement of the mobile medical device 28 along a floor surface F. For example, the at least one powered caster assembly 49 may include a first powered caster assembly 49A and a second powered caster assembly 49B. Where the mobile medical device 28 (e.g., the patient transport apparatus 30) includes the first powered caster assembly 49A and the second powered caster assembly 49B, thefirst powered caster assembly 49A may be operatively attached to the mobile medical device 28 at one end (e.g., to the base 34 of the patient transport apparatus 30 at one of the head end HE and the foot end FE), and the second powered caster assembly 49B may be operatively attached to the mobile medical device 28 at another end (e.g., to the base 34 of the patient transport apparatus 30 at the other of the head end HE and the foot end FE). Referring to Figure 1, the base 34 of the patient transport apparatus 30 may define a first lateral side LSI and a second lateral side LS2 opposite the first lateral side LSI. In examples where the patient transport apparatus 30 includes the first powered caster assembly 49A and the second powered caster assembly 49B, the first powered caster assembly 49A may be operatively attached to the base 34 at one of the first lateral side LSI and second lateral side LS2, and the second powered caster assembly 49B may be operatively attached to the base 34 at the other of the first lateral side LS 1 and second lateral side LS2.

[0035] It should also be appreciated that where the mobile medical device 28 (e.g., the patient transport apparatus 30) includes the first powered caster assembly 49A and the second powered caster assembly 49B, when operating in the first state (described in further detail below), the powered caster drive system 48 is configured to operate the hub motor 72 of the first powered caster assembly 49A and the second powered caster assembly 49B, respectively, to selectively modulate application of torque to the wheel 50 of the first powered caster assembly 49A and the second powered caster assembly 49B, respectively, during operation of the steer lock assembly 64 in the steer locked state SL (also described in further detail below). Likewise, when operating in the second state (described in further detail below), the powered caster drive system 48 is configured to operate the hub motor 72 of the first powered caster assembly 49A and the second powered caster assembly 49B, respectively, to inhibit the hub motor 72 from applying torque tothe wheel 50 of the first powered caster assembly 49A and the second powered caster assembly 49B, respectively, during operation of the steer lock assembly 64 in the non-steer locked state UL (also described in further detail below). Furthermore, as described in further detail below, a controller 76 may be configured to operate both the hub motor 72 of the first powered caster assembly 49A and the second powered caster assembly 49B to selectively modulate application of torque to the wheel 50 of the first powered caster assembly 49A and the second powered caster assembly 49B, respectively, in response to user engagement with a first user input and / or a second user input.

[0036] As shown for the patient transport apparatus 30 illustrated in Figure 1, a pair of loading wheels 63 may be coupled to the support frame 36 to assist with loading of the patient transport apparatus 30 into the emergency vehicle and unloading of the patient transport apparatus 30 out of the emergency vehicle. In the configuration shown, the loading wheels 63 are arranged nearer the head end HE than the foot end FE, but the loading wheels 63 may be placed in other locations to facilitate loading and / or unloading of the patient transport apparatus 30 into and out of the emergency vehicle, or for other purposes.

[0037] As best shown in Figures 2A-2C, the at least one powered caster assembly 49 also include a steer lock assembly 64. The steer lock assembly 64 being operable between a steer locked state SL (see Figure 2B) and a non-steer locked state UL (see Figures 2A and 2C). The at least one powered caster assembly 49 may also include a brake assembly 66, which is respectively configured to facilitate braking of the wheel 50 about the rotational axis R, with the brake assembly 66 being operable between a braked state BS and an unbraked state UB. It should be appreciated that the unpowered caster assemblies 52 may include the steer lock assembly 64 and / or the brake assembly 66. The configuration of the steer lock assembly 64 and the brake assembly 66 are notparticularly limited for the purposes of this disclosure. Examples of suitable steer lock assemblies 64 and brake assemblies 66 are disclosed in U.S. Patent No. 11,197,791, filed Nov. 21, 2019, the contents of which are hereby incorporated by reference in its entirety.

[0038] Figures 2A-2C are partial cross-sectional views of one of the powered caster assemblies 49 which show the states of one of the steer lock assemblies 64 and brake assemblies 66. More specifically, Figure 2A shows a neutral configuration in which the steer lock assembly 64 is in the non-steer locked state UL and in which the brake assembly 66 is in an unbraked state UB. Figure 2B shows a configuration in which the steer lock assembly 64 is in the steer locked state SL and in which the brake assembly 66 is in an unbraked state UB. Figure 2C shows a configuration in which the steer lock assembly 64 is in the non-steer locked state UL and in which the brake assembly 66 is in a braked state BS.

[0039] The non-steer locked state UL, as shown in Figures 2A and 2C, refers to a positioning of the steer lock assembly 64 relative to the wheel 50 wherein the steer lock assembly 64 does not impede the rotation of the wheel 50 about its swivel axis S. In the configuration illustrated in Figures 2A-2C, a steer lock pin 67 A is spaced from a steer lock receiver 67B where the steer lock assembly is in the non-steer locked state UL such that the steer lock assembly 64 does not impede the rotation of the wheel 50 about its swivel axis S. Conversely, the steer locked state SL, as shown in Figure 2B, places the steer lock assembly 64 in a position relative to the wheel 50 that impedes the rotation of the wheel 50 about the swivel axis S to assist a user in steering the patient transport apparatus 30 along the floor surface F. In the configuration illustrated in FIGS. 2A-2C, the steer lock pin 67 A is engaged with the steer lock receiver 67B where the steer lock assembly is in the steer locked state SL such that the steer lock assembly 64 impedes the rotation of the wheel 50 about its swivel axis S.

[0040] The braked state BS, as shown in Figure 2C, refers to a positioning of the brake assembly 66 relative to its wheel 50 whereby a brake pad 68 of the brake assembly 66 is engaged with an outer end surface 53 of the wheel 50 so as to prevent the rotation of the wheel 50 about its rotational axis R. The brake pad 68 is coupled to a plunger 57 (e.g., via a fastener, a pin, and the like; not shown) which, in turn, extends through an interior region of the stem 60. A plunger spring 59 normally biases the plunger 57 such that the brake pad 68 is disengaged from the outer surface 53 of the wheel 50, corresponding to the unbraked state UB (see Figures 2A and 2B). The unbraked state UB, as shown in Figures 2A and 2B, refers to a positioning of the brake assembly 66 relative to its wheel 50 whereby the brake pad 68 of the brake assembly 66 is not engaged with the outer end surface 53 of the wheel 50, thereby allowing free rotation of the wheel 50 about its rotational axis R.

[0041] In the configurations shown, each of the at least one powered caster assembly 49 respectively includes an actuator 70 to change the mode of operation of the steer lock assembly 64 and / or the brake assembly 66. More specifically, the actuator 70 is operable to place the steer lock assembly 64 in a non-steer locked state UL or a steer locked state SL and may additionally be operable to place the brake assembly 66 in a braked state BS or an unbraked state UB. For example, as shown in Figures 2A-2C, the actuator 70 may be configured to engage various members of the steer lock assembly 64 (e.g., the steer lock pin 67 A) and / or the brake assembly 66 to change the state of the steer lock assembly 64 and / or the brake assembly 66. In configurations where the mobile medical device 28 includes more than one steer lock assembly 64 and / or brake assembly 66, the plurality of steer lock assemblies 64 and / or brake assemblies 66 may be interconnected to operate in a coordinated manner (e.g., operationally linked together utilizing a cable assembly). Examples of suitable cable arrangements for interconnecting a plurality of steerlock assemblies 64 and / or brake assemblies 66 is disclosed in are disclosed in U.S. Patent No.11,197,791, filed Nov. 21, 2019, the contents of which are hereby incorporated by reference in its entirety.

[0042] In the representative versions illustrated throughout the drawings, the actuator 70 is in the form of a foot pedal 70 configured to be engaged by the foot of a caregiver to apply a force to the foot pedal 70 (the terms “foot pedal 70” and “actuator 70” may be used interchangeably herein unless otherwise indicated). As shown in Figures 2A-2C, the foot pedal 70 includes a body having a profile that defines adjacent first, second and third notched regions (not shown in detail) that are shaped to be separately respectively engageable with the plunger 57 to change operation of the steer lock assembly 64 and / or the brake assembly 66.

[0043] The foot pedal 70 is mounted to the base frame 35, which is depicted as mounted to the base 34, via an axle pin 65 passing through an opening. The axle pin 65 is attached to the base frame 35 or base 34. The foot pedal 70 is arranged to rotate about a pivot axis defined by the axle pin 65 (e.g., rotation in either a counterclockwise direction or clockwise direction as shown in Figures 2B and 2C by comparison with Figure 2A) (i.e., the axle pin 65 defines the pivot axis) upon force F3 being applied to the foot pedal 70 to rotate from the arrangement shown in Figure 2 A to the arrangement shown in Figure 2C, or upon force Fl being applied to the foot pedal 70 to rotate from the arrangement shown in Figure 2A to the arrangement shown in Figure 2B.

[0044] The brake assembly 66 also includes the plunger spring 59 which, as noted above, is positioned between the stem 60 and the plunger 57. The spring 59 normally biases the plunger 57 such that the brake pad 68 is disengaged from the outer surface 53 of the wheel 50, corresponding to the unbraked state UB (see Figures 2A and 2B). The engagement of the brake pad 68 to the outer end surface 53 of the wheel 50, and conversely the disengagement of the brakepad 68 from the outer end surface 53 of the wheel 50, is accomplished when the user applies force to one of the sides of the actuator 70 (e.g., the pedal 70) to rotate around the pivot axis defined by the axle pin 65 in a clockwise or counterclockwise direction so that a desired one of the first, second or third notched regions is engaged with the plunger 57.

[0045] As shown in Figure 2C, when the user applies force F3 to move the foot pedal 70 such that the first notched region comes into engagement with the plunger 57, a downward force F4 is applied from foot pedal 70 to the plunger 57. This force F4 moves the plunger 57 and causes the plunger 57 to exert compressive force on the spring 59 and, thus, onto the stem 60. The movement of the plunger 57 downward towards the wheel 50 also causes the movement of the coupled brake pad 68 into engagement with the outer surface 53 of the wheel 50 to exert a force F5 on the outer surface 53 (corresponding to the force F4), thereby preventing the wheel 50 from rotating freely about the rotational axis R in a clockwise or counterclockwise direction upon force being applied to the patient transport device 30 to move the patient transport apparatus 30 along the floor surface F. When the user applies force Fl to move the foot pedal 70 such that the third notched region comes into engagement with the plunger 57 as shown in Figure 2B, or such that the second notched region comes into engagement with the plunger 57 as shown in Figure 2A, the force F4 is relieved, and the biasing force of the spring 59 moves the plunger 57 upward such that the brake pad 68 is disengaged from the outer end surface 53 of the wheel 50, thereby allowing the wheel 50 to freely rotate about rotational axis R in a clockwise or counterclockwise direction.

[0046] As best illustrated in Figures 2A-2C, the steer lock assembly 64 includes an interface plate 71 which defines one or more lock receivers 67B arranged to receive the steer lock pin 67A. The interface plate 71 generally extends outwardly in a direction away from the swivel axis S and is generally parallel to the floor surface F. In certain versions, the interface plate 71may be a part of, or integrally formed with, the neck 58. Alternatively, the interface plate 71 may be coupled to and extend outwardly away from the neck 58. The interface plate 71 (and, thus, the lock receivers 67B defined thereby) swivel about the swivel axis S in conjunction with the neck 58, fork 56 and wheel 50. Each of the lock receivers 67B may define one or more openings, slots, apertures, notches, holes, and the like, which are sized and shaped to receive the steer lock pin 67A of the steer lock assembly 64 so as to prevent the rotation of the neck 58, the fork 56, and the wheel 50 about the swivel axis S when the steer lock assembly 64 is in the steer locked state SL (as shown and described below in conjunction with Figure 2B).

[0047] As best shown in Figures 4A and 4B, the steer lock assembly 64 includes a sleeve member 73 that is shaped to be engageable with the foot pedal 70 to position the steer lock assembly 64 in the steer locked state SL. The steer lock pin 67A is coupled to the sleeve member 73 via a fastener (not shown in detail) and is movable vertically relative to the sleeve member 73 via a pin biasing element 75A, which urges the steer lock pin 67A away from the fastener and allows the steer lock pin 67A to move vertically relative to the sleeve member 73. A sleeve biasing element 75B is interposed between the sleeve member 73 and a flange portion of the stem 60, and is arranged to urge the sleeve member 73 vertically upwardly towards the arrangement depicted in Figure 2A in absence of engagement by the actuator 70 (e.g., as depicted in Figure 2B).

[0048] When the caster assembly 49 is in the steer locked state SL illustrated in Figure 2B, the steer lock pin 67 A is axially aligned with one of the lock receivers 67B of the interface plate 71 . This occurs when the wheel 50 of the associated caster assembly 49 is positioned in the leading or trailing position relative to the head end of the patient transport apparatus 30. To place the caster assembly 49 in the steer locked state SL, the foot pedal 70 is brought into contact with the sleeve member 73 and a downward force F2 is applied on the sleeve member 73 to move the steerlock pin 67 A towards the steer lock receiver 67B. The configuration of the sleeve member 73 allows for the foot pedal 70 be placed in the steer lock state SL even during situations where the wheel 50 is not yet in a trailing orientation. In this case, the pin biasing element 75 A applies a biasing force against the steer lock pin 67A so that the steer lock pin 67A is biased against an upper surface of the interface plate 71 spaced from the lock receivers 67B (arrangement not shown in detail). However, because the steer lock pin 67 A is not yet axially aligned with the one or more steer lock receivers 67B of the interface plate 71, once the wheel 50 is oriented in the correct orientation to define the steer locked state SL, then the steer lock pin 67 A becomes axially aligned with the steer lock receiver 67B and is biased thereinto owing to the biasing force from the pin biasing element 75 A. Once the steer lock pin 67 A is in the steer lock receiver 67B, the interface plate 71, the neck 58, and the wheel 50 are limited or prevented from swiveling about the swivel axis S.

[0049] Conversely, when the patient transport apparatus 30 is in the non-steer locked state UL, corresponding to either the neutral mode illustrated in Figure 2 A or the braked state BS illustrated in Figure 2C, the foot pedal 70 is not in contact with the sleeve member 73 and is therefore not applying a downward force F2 on the sleeve member 73 to move it towards the lock receiver 67B. As such, the compression on the pin biasing element 75 A and the sleeve biasing element 75B associated with the downward force F2 has been relieved and is absent, and the biasing force of the sleeve biasing element 75B moves the sleeve member 73 in a direction away from the interface plate 71 (compare Figure 2A to the positioning in Figures 2B and 4B). The biasing force of the sleeve biasing element 75B and associated movement of the sleeve member 73 also moves the steer lock pin 67A away from the locking receiver 67B. This movement retracts the steer lock pin 67A such that it is no longer contained or otherwise received within the steerlock receiver 67B, thereby allowing the interface plate 71 , the neck 58, and the wheel 50 to swivel about the swivel axis S when a user moves the patient transport apparatus 30. When a user wishes to move the steer lock assembly 64 from the non-steer locked state US to the steer locked state SL, or from the steer locked state SL to the non-steer locked state US, the user either applies upward force Fl or a downward force F3 on the foot pedal 70.

[0050] As best shown in Figures 1 and 4, each of the powered caster assemblies 49 includes a hub motor 72. The hub motor 72 is interposed between the wheel 50 and the wheel support 54 (e.g., the fork 56 and / or the axle 62) and is configured to selectively modulate application of torque to the wheel 50 to facilitate movement of the mobile medical device 28 (e.g., the patient transport apparatus 30) along the floor surface F. As used herein, the phrase “selectively modulate application of torque” may refer to the hub motor 72 applying a positive torque to drive the wheel 50 to facilitate movement of the mobile medical device 28 along the floor surface F, or may refer to applying a negative torque to brake the wheel 50 (also known as regenerative braking). The hub motor 72 is realized as an electric motor configured to be energized by a power source 78 (described in further detail below) such that the electric motor outputs torque about the rotational axis R to drive the wheel 50 about the rotational axis R.

[0051] As will be appreciated from the subsequent description below, power, data, signals, and the like may be exchanged between the hub motor 72, the controller 76, the power source 78, other portions of the control system 74, and / or other portions of the mobile medical device 28 in a number of different ways, including such as via wired electrical communication such as via an electrical cable, harness, and the like (see Figure 5; depicted schematically), and / or via one or more types of wireless communication. In some versions, power, data, signals, and the like can be exchanged with the hub motor 72 via a physical electrical cable which extends from the hub motor72 to another portion of the support structure 32. Tn some versions, and as is described in greater detail below in connection with Figures 7A-12B, one or more types of slip rings 79 may be used to transmit power and / or data between pivoting or rotating components, such as between the stem 60 and the neck 58 of the powered caster assembly 49 to facilitate operation of the hub motor 72 via the controller 76. Other configurations are contemplated.

[0052] The hub motor 72 may be an AC electric motor, a DC electric motor, a synchronous electric motor, an asynchronous electric motor, the like, and combinations thereof. The hub motor 72 may be a brushless or brushed electric motor. The hub motor 72 may directly drive the wheel 50, or a reduction gearset (e.g., a planetary gearset; not shown) may be interposed between the hub motor 72 and the wheel 50. Accordingly, the hub motor 72 is configured to selectively modulate application of torque to the wheel 50 to facilitate movement of the mobile medical device 28 (e.g., the patient transport apparatus 30) along the floor surface F. In some versions, when power is not supplied to the hub motor 72 from the power source 78 (described in further detail below), the hub motor 72 may act as a brake to decelerate the wheel 50. In other versions, the wheel 50 is permitted to rotate freely when power is not supplied to the hub motor 72.

[0053] The powered caster drive system 48 is operable between a plurality of states. In a first state SI, the powered caster drive system 48 is operable to operate the hub motor 72 to selectively modulate application of torque to the wheel 50 during operation of the steer lock assembly 64 in the steer locked state SL. In a second state S2, the powered caster drive system 48 is operable to inhibit the hub motor 72 from applying torque to drive the wheel 50 during operation of the steer lock assembly 64 in the non-steer locked state UL. In other words, the powered caster drive system 48 is configured to apply torque to drive the wheel 50 when the steer lock assembly 64 in the steer locked state SL. By inhibiting the hub motor 72 from applying torque to drive thewheel 50 during operation of the steer lock assembly 64 in the non-steer locked state UL, the powered caster drive system 48 prevents the hub motor 72 from moving the mobile medical device 28 (e.g., the patient transport apparatus 30) in an unintended direction due to the steer lock assembly 64 being in the non-steer locked state UL (i.e., where the wheel 50 is free to pivot about the swivel axis S, and thus the direction of propulsion of the mobile medical device 28 along the floor surface F may be less predictable).

[0054] The present disclosure is also directed to a control system 74 for operating the powered caster drive system 48. The control system 74 includes a controller 76 in communication with at least the powered caster drive system 48 such that the controller 76 is configured to operate the powered caster drive system 48. In some examples, the control system 74 is integrated with the powered caster drive system 48, but it is also contemplated that the controller 76 may be part of the mobile medical device 28 (e.g., the patient transport apparatus 30) in which the powered caster drive system 48 is incorporated and thus is configured to operate the powered caster drive system 48 as well as other aspects of the mobile medical device 28. Figure 5 illustrates one exemplary configuration of a control system 74 for controlling the powered caster drive system 48 as well as other aspects of a patient transport apparatus 30. Other configurations of the control system 74 for operating the powered caster drive system 48 are contemplated.

[0055] In some versions, the controller 76 includes a memory 77. The memory 77 may be any memory suitable for storage of data and computer-readable instructions. For example, the memory 77 may be a local memory, an external memory, or a cloud-based memory realized as random-access memory (RAM), non-volatile RAM (NVRAM), flash memory, or any other suitable form of memory. The controller 76 generally includes one or more microprocessors for processing instructions or for processing algorithms stored in memory to control operation of atleast the powered caster drive system 48. Additionally or alternatively, the controller 76 may include one or more microcontrollers, field programmable gate arrays, systems on a chip, discrete circuitry, and / or other suitable hardware, software, or firmware that is capable of carrying out the functions described herein. The controller 76 may be carried on-board the powered caster drive system 48, onboard the mobile medical device 28 (e.g., the patient transport apparatus 30), or may be remotely located. In one version, the controller 76 is mounted to the base 34 of the patient transport apparatus 30.

[0056] In some versions, the controller 76 includes an internal clock to keep track of time, such as a microcontroller clock. The microcontroller clock may include a crystal resonator; a ceramic resonator; a resistor, capacitor (RC) oscillator; or a silicon oscillator. Examples of other internal clocks other than those disclosed herein are fully contemplated. The internal clock may be implemented in hardware, software, or both. The controller 76 may include one or more subcontrollers configured to control of at least the powered caster drive system 48. In some cases, one of the subcontrollers may be attached to the powered caster drive system 48 with another attached to the mobile medical device 28 (e.g., the patient transport apparatus 30). Power to the powered caster drive system 48, other aspects of the mobile medical device 28 (e.g., the patient transport apparatus 30) and / or the controller 76 may be provided by the power source 78 (described in further detail below). The controller 76 may communicate with at least the powered caster drive system 48 via wired or wireless connections. The controller 76 generates and transmits control signals to at least the powered caster drive system 48, or components thereof (e.g., the hub motor 72), to operate at least the powered caster drive system 48 to perform one or more desired functions.

[0057] The control system 74 may also include a user feedback device 80 (illustrated schematically in Figure 5) coupled to the controller 76 to indicate to the user various information about the operational status of the powered caster drive system 48, and, optionally, other aspects of the mobile medical device 28 (e.g., the patient transport apparatus 30). In one version, the user feedback device 80 includes one of a visual indicator, an audible indicator, and a tactile indicator. As one example, the user feedback device 80 may include an LED disposed relative to the mobile medical device 28 (e.g., the patient transport apparatus 30) and configured to illuminate to indicate to the user that the steer lock assembly 64 is in the steer locked state SL and to not illuminate where the steer lock assembly 64 is in the non-steer locked state UL. Additional user feedback devices 80 are contemplated.

[0058] The lift mechanism 37 of the patient transport apparatus 30 described above may include one or more of an electric actuator, a hydraulic actuator, a pneumatic actuator, combinations thereof, or any other suitable types of actuators, and each actuator may include more than one actuation mechanism. The lift mechanism 37 can be like that shown in the U.S. Patent Application Publication No. 2018 / 0303689 Al, the disclosure of which is hereby incorporated by reference in its entirety. In configurations where the mobile medical device 28 is realized as the patient transport apparatus 30, the controller 76 may be in communication with the lift mechanism 37 (illustrated schematically in Figure 5) and is configured to operate the lift mechanism 37 to lift and lower the patient support deck 38 relative to the base 34. For example, a lift interface 82 (see Figure 5; depicted schematically), may be operatively attached to patient transport apparatus 30 and include lift input controls arranged for engagement by the user and disposed in electrical communication with the controller 76 to facilitate operation of the lift mechanism 37 to lift and lower the patient support deck 38 relative to the base 34.

[0059] In some versions, the steer lock assembly 64 may be electronically operable between the steer locked state SL and the non-steer locked state UL and / or the brake assembly 66 may be electronically operable between the braked state BS and the unbraked state UB. For example, the actuator 70 as described above may be electronically operable, such as with a solenoid, motor, and the like. In these examples, as illustrated schematically in Figure 5, the controller 76 may also be in communication with and configured to operate the steer lock assembly 64 between the steer locked state SL and the non-steer locked state UL, and / or to operate the brake assembly 66 between the braked state BS and the unbraked state UB.

[0060] The controller 76 may be configured to operate the powered caster drive system 48 in the first state SI in response to determining that the steer lock assembly 64 is in the steer locked state SL and to operate the powered caster drive system 48 in the second state S2 in response to determining that the steer lock assembly 64 is in the non-steer locked state UL. A variety of configurations for enabling the controller 76 to determine the state of the steer lock assembly 64 are contemplated.

[0061] In some versions, the steer lock assembly 64 may further include a lock switch 84. As is illustrated schematically in Figures 2A-2C, the lock switch 84 may, for example, be a limit switch disposed within the steer lock assembly 64 and configured to determine whether the components of the steer lock assembly 64 (e.g., the steer lock pin 67A) are positioned such that the steer lock assembly 64 is in the steer locked state SL. In some versions, the lock switch 84 is in communication with the controller 76 (see Figure 5; depicted schematically) and is configured to provide at least one of a locked signal NL and an unlocked signal NU to the controller 76. In some versions, the controller 76 is configured to operate the powered caster drive system 48 in the first state SI in response to receiving the locked signal NL (indicative of the steer lock assembly64 being in the steer locked state SL). Additionally or alternatively, the controller 76 may be configured to operate the powered caster drive system 48 in the second state S2 in response to receiving the unlocked signal NU (indicative of the steer lock assembly 64 being in the non-steer locked state UL). It should also be appreciated that in some configurations, the controller 76 may change the state of the powered caster drive system 48 in response to an absence of the locked signal NL and / or the unlocked signal NU. Although not shown in detail throughout the drawings, the controller 76 may change the state of the powered caster drive system 48 based on the operational mode of the unpowered caster assembly 52. For example, where the unpowered caster assembly 52 includes a brake assembly 66, the controller 76 may be configured to operate the powered caster drive system 48 in the second state S2 to inhibit the hub motor 72 from applying torque to the wheel 50.

[0062] In Figures 2A-2C, the lock switch 84 is schematically depicted as being arranged adjacent to the interface plate 71, and is configured to sense the presence of the steer lock pin 67 A to confirm operation in the steer locked state SL (see Figure 2B), whereby retraction of the steer lock pin 67 A away from the interface plate 71 causes the lock switch 84 to sense or otherwise determine the absence of the steer lock pin 67A. However, it will be appreciated that other configurations are contemplated, and the lock switch 84 could be disposed, supported, or otherwise arranged in a number of different ways, and could be of various styles, types, and / or configurations sufficient to sense changes in operation between the steer locked state SL and the non-steer locked state UL, either by sensing movement of the steer lock pin 67 A itself or other components. By way of non-limiting example, in some versions, such as is depicted schematically in Figures 7A- 7B, the lock switch 84 could be operatively attached to the actuator 70 (e.g., the foot pedal 70) and / or to the axle pin 65 to sense rotational movement of the actuator 70 in order to associatespecific rotational positions of the actuator 70 with operational states of the steer lock assembly 64. Here, one or more encoders, hall-effect sensors, limit switches, and the like, or combinations thereof, could be used to determine changes between the steer locked state SL and the non- steer locked state UL.

[0063] Here too, it will be appreciated that this type of lock switch 84 could also serve as a brake switch 85 to determine changes in operation of the brake assembly 66 between the braked state BS and the unbraked state UB. In some versions, the controller 76 could monitor signals from the brake switch 85 and could be configured to operate the powered caster drive system 48 in the first state SI in response to determining that the brake assembly 66 is in the unbraked state UB and to operate the powered caster drive system 48 in the second state S2 in response to determining that the brake assembly 66 is in the braked state BS in order to inhibit driving during braking. In some versions, the control system 74 is configured with discrete lock and brake switches 84, 85, whereas they may be integrated in other versions such as described above. It will be appreciated that the term “switches” may be used interchangeably with the term “sensors” unless otherwise indicated herein. Those having ordinary skill in the art will appreciate that the lock switch 84 and / or the brake switch 85 may be of a number of styles, types, and / or configurations, and may be arranged in various ways. In some versions, such as where the lock switch 84 is configured as a hall-effect sensor, multiple emitters, magnetic materials, ferrous materials, and the like may be used to sese the specific orientation of the caster assembly 49 about the swivel axis S, such as via polarized magnets coupled to the interface plate 71 to differentiate between leading and trailing orientations or other orientations. In some versions, the interface plate 71 or another portion of the caster assembly 49 may be realized as an encoder wheel that is sensed by an optical sensor type of lock switch 84. Other configurations are contemplated.

[0064] In configurations where the mobile medical device 28 is realized as the patient transport apparatus 30, the patient transport apparatus 30 may further include a patient load sensor 86 (shown schematically in Figure 5) coupled to the controller 76 and to one of the base 34, the support frame 36, and the lift mechanism 37. The patient load sensor 86 may generate a signal responsive to the weight of a patient being disposed on the patient support deck 38. For example, the load sensor 86 includes load cells coupled to the controller 76 and arranged to detect and / or measure the weight disposed on the patient support deck 38. The load cells may be arranged in the base 34, the support frame 36, patient support deck 38 or any other suitable location to measure the weight disposed on the patient support deck 38. The controller 76 is configured to detect the signal from the patient load sensor 86. In some examples, the operation of the hub motor 72 may change based on detection of the signal generated by the patient load sensor 86 to compensate for changes in weight disposed on the patient support deck 38 when the controller 76 operates the powered caster drive system 48 (particularly, the hub motor 72). In other words, the controller 76 may control voltage and / or current supplied to the hub motor 72 based on patient weight. Additionally, in some examples the controller 76 may operate the hub motor 72 at different speed limits for when the signal generated by the patient load sensor 86 indicates that the patient support deck 38 is loaded versus unloaded.

[0065] In some examples, where the mobile medical device 28 is realized as the patient transport apparatus 30, components of the patient transport apparatus 30 (e.g., one or more of the base 34, the support frame 36, the patient support deck 38, and the side rails 44, 46) may be configured to be coupled to an ancillary device (not shown), such as a cot loading system. In other versions, the ancillary device is another device configured to be coupled to the patient transport apparatus 30. In these examples, an ancillary device sensor 88 may be coupled to the controller76 (illustrated schematically in Figure 5) and configured to generate a signal responsive to whether the ancillary device is coupled to one or more of the base 34, the support frame 36, the patient support deck 38, and the side rails 44, 46. The controller 76 is configured to detect the signal from the ancillary device sensor 88. When the controller 76 detects the ancillary device being coupled to one or more of base 34, the support frame 36, the patient support deck 38, and the side rails 44, 46, the controller 76 may be configured to operate other aspects of the patient transport apparatus 30 (e.g. the lift mechanism 37 or the brake assembly 66) accordingly.

[0066] In the illustrated version, the power source 78 includes a battery power supply 90 (shown schematically in Figure 5) to permit the mobile medical device 28 (e.g., the patient transport apparatus 30) to be supplied with power during transport. In many versions, the mobile medical device 28 (e.g., the patient transport apparatus 30) includes a tether (not shown) coupled to the controller 76 and configured to be coupled to the external power source 92 (e.g. plugged in) to charge the battery power supply 90 and provide power for other functions of the mobile medical device 28 (e.g., the patient transport apparatus 30). In some examples, the battery power supply 90 may include a plurality of battery power supplies 90. For example, the patient transport apparatus 30 may include one dedicated battery power supply 90 for energizing the powered caster drive system 48, and another battery power supply 90 for operating other aspects of the patient transport apparatus 30 (e.g., the lift mechanism 37). The specific implementation of the battery power supply is not particularly limited for the purposes of this disclosures and may include lithium-ion batteries and any other current or future battery type suitable for the application.

[0067] In some versions, the powered caster drive system 48 or the mobile medical device 28 further includes an electrical disconnect 94 interposed between the power source 78 and the hub motor 72. The electrical disconnect 94 is configured to permit electrical communicationbetween the power source 78 and the hub motor 72 where the powered caster drive system 48 is in the first state SI and to interrupt electrical communication between the power source 78 and the hub motor 72 where the powered caster drive system 48 is in the second state S2. In some examples, such as is illustrated schematically in Figure 5, the controller 76 is configured to operate the electrical disconnect 94 directly. By way of illustrative example, the electrical disconnect 94 may be realized as one or more relays, circuits, or other components which can be operated via the controller 76 to facilitate changes in operation of the powered caster drive system 48. Here, a relay 97 may be provided to interrupt power from flowing between the battery power supply 90 and the hub motor 72 of the powered caster assembly 49. In some versions, the electrical disconnect 94 may not require any software control and instead may be a mechanical electrical disconnect 94 that is not necessarily in communication with the controller 76. For example, the electrical disconnect 94 may include a physical switch that is disposed in electrical communication between the hub motor 72 and the battery power supply 90 but is not necessarily disposed in communication with the controller 76. Here, the electrical disconnect 94 may be arranged so as to be activated separately from the foot pedal 70, requiring separate user engagement to confirm that powered operation of the powered caster assembly 49 is desired. In such situations, the electrical disconnect 94 may be situated adjacent to the foot pedal 70 and require separate engagement. In some versions, the electrical disconnect 94 may be configured such that it cannot be activated unless the steer lock assembly 64 is in the steer locked state SL. Here, for example, the electrical disconnect 94 could be arranged (not shown in detail) so as to be activated upon movement of the foot pedal 70 to the position which activates the steer locked state SL. Other configurations are contemplated.

[0068] In some versions, the electrical disconnect 94 or another portion of the powered caster assembly 49 may include an electrical terminal 93 arranged for movement relative to anelectrical contact 95. For example, the terminal 93 may be disposed in electrical communication with the contact 95 during operation of the powered caster drive system 48 in the first state SI to permit electrical communication between the power source 78 and the hub motor 72, and the terminal 93 may be spaced from the contact 95 to interrupt electrical communication between the terminal 93 and the contact 95 during operation of the powered caster drive system 48 in the second state S2 to interrupt electrical communication between the power source 78 and the hub motor 72. In some versions, the electrical disconnect 94 may be realized as a part of one of the slip rings 79, such as is described in greater detail below in connection with Figure 9 where electrical communication across the slip ring 79 is interrupted based on the relative rotational positions of components of the slip ring 79, and / or as is described in greater detail below in connection with Figures 10A-10B where components of the slip ring 79 employ one or more terminals 93 and one or more contacts 95 which move out of physical contact with each other in response to movement of the steer lock pin 67A. Other configurations are contemplated.

[0069] In some versions, a speed sensor 96 (shown schematically in Figure 5) is disposed on the mobile medical device 28 (e.g., the patient transport apparatus 30) and in communication with the controller 76. The speed sensor 96 is configured to generate a signal representative of the speed of the mobile medical device 28 (e.g., the patient transport apparatus 30) relative to the floor surface F. For example, where the mobile medical device 28 is realized as the patient transport apparatus 30, the speed of the patient transport apparatus 30 relative to the floor surface F may be obtained by the speed sensor 96 generating a signal responsive to one or more of a current speed of the base 34 moving relative to the floor surface F and a current rotational speed of the wheel 50. Based on the speed of the patient transport apparatus 30 relative to the floor surface F as determined by the speed sensor 96, the controller 76 may be configured to adjust the at least oneof the torque generated by the hub motor 72 and the speed of the hub motor 72 such that the speed of the patient transport apparatus relative to the floor surface does not exceed a pre-defined threshold. For example, the controller 76 may control voltage and / or current supplied to the hub motor 72. The pre-defined threshold may be adjusted based on a variety of factors such as patient weight, slope of the floor surface, etc. roo7oi As shown schematically in Figure 5, a first user input 98 may in communication with the controller 76 and arranged for user engagement (e.g., operatively attached to the mobile medical device 28 in a location suitable for user engagement). The controller 76 may be configured to operate the hub motor 72 based on user engagement with the first user input 98.

[0071] In some versions, the first user input 98 may include a first user input control 100. configured to provide a first user input signal IS1 to the controller 76 in response to user engagement with the first user input control 100. The first user input signal IS1 may pertain to at least one of a desired direction for the hub motor 72 to modulate application of torque to the wheel 50, a desired speed for the mobile medical device 28 (e.g. the patient transport apparatus 30) to move along the floor surface F, and / or the presence of user engagement with the first user input control 100. In these examples, the controller 76 is configured to operate the hub motor 72 based on the first user input signal IS1. The specific implementation of the first user input control 100 is not particularly limited for the purposes of this disclosure and may include button(s), toggle switch(es), rotary dial(s), slider(s), keyboard(s), touchscreen) s), joystick(s), lever(s), knob(s), throttle(s), foot pedal(s), the like, and combinations thereof.

[0072] The first user input 98 may be implemented as a plurality of discrete first user input controls 100. For example, the first user input 98 may include a speed input control 100a configured to provide a speed input signal SS to the controller 76 based on user engagement withthe speed input control 100a. Here, the speed input signal SS pertains to a desired speed for the mobile medical device 28 (e.g., the patient transport apparatus 30) to move along the floor surface F, and the controller 76 is configured to operate the hub motor 72 based on the speed input signal SS. In some versions, the first user input 98 may include a direction input control 100b configured to provide a direction input signal DS to the controller 76 based on user engagement with the direction input control 100b. Here, the direction input signal DS pertains to a desired direction for the hub motor 72 to modulate application of torque to the wheel 50, and the controller 76 is configured to operate the hub motor 72 based on the direction input signal DS. In some versions, the first user input 98 may include an engagement input control 100c configured to provide an engagement input signal to the controller 76 based on user engagement with the engagement input control 100c. The engagement input signal ES pertains to the presence of user engagement (e.g., touching) with the engagement input control 100c, and the controller 76 is configured to operate the hub motor 72 based on the engagement input signal ES.

[0073] As shown in Figures 1 and 6, in some versions, the first user input 98 may include a handle 102 operatively attached to the mobile medical device 28 (e.g., adjacent to the foot end FE of the support structure 32 of the patient transport apparatus 30) and configured to be gripped by the user. In this example, the first user input control 100 is implemented as a throttle 104 (see also Figure 6). Here, the throttle 104 is operatively attached to the handle 102 and is arranged for movement relative to the handle 102 in response to user engagement. The manner of movement of the throttle 104 relative to the handle 102 is not particularly limited for the purposes of this disclosure. While Figure 6 shows the throttle 104 arranged for user selected rotation relative to the handle 102 about a central axis C, other configurations of the throttle 104 are contemplated, such as a thumb lever, etc. Exemplary configurations of a handle 102 including a throttle 104 aredisclosed in U.S. Patent Application No. 18 / 564,199, filed Nov. 27, 2023, the disclosure of which are hereby incorporated by reference in its entirety.

[0074] Where the first user input 98 is implemented as a handle 102 and a throttle 104, the throttle 104 is configured to generate the first user input signal IS1 in response to user engagement with the throttle 104, and the controller 76 is configured to operate the hub motor 72 based on the first user input signal IS1. In these examples, the first user input signal IS1 generated by the throttle 104 may pertain to a desired speed for the mobile medical device 28 (e.g., the patient transport apparatus 30) to move along the floor surface F based on the magnitude of the movement of the throttle 104 relative to the handle 102. For example, in the configuration of Figure 6, the first user input signal IS1 generated by the throttle 104 may pertain to the desired speed for the mobile medical device 28 to move along the floor surface F based on the magnitude of the angular rotation of the throttle 104 about the central axis C. In other words, the more the throttle 104 is twisted relative to the handle 102, the throttle 104 generates a first user input signal IS1 defines the speed input signal SS pertaining to a greater desired speed for the mobile medical device 28 to move along the floor surface F. Additionally or alternatively, the first user input signal IS1 generated by the throttle 104 may pertain to a desired direction for the hub motor 72 to modulate application of torque to the wheel 50 based on the direction of the movement of the throttle 104 relative to the handle 102. For example, in the configuration of Figure 6, the first user input signal IS 1 generated by the throttle 104 may pertain to operating the hub motor 72 to modulate application of torque to the wheel 50 in one direction based on rotation of the throttle 104 relative to the handle 102 in a first direction DI, and to operating the hub motor 72 to modulate application of torque to the wheel 50 in an opposite direction based on rotation of the throttle 104 relative to the handle 102 in a second direction D2 opposite the first direction DI. Thus, the first user input signal IS1may also define the direction input signal DS. Likewise, user presence may be determined in various ways, including with a discrete presence sensor 105 arranged in the handle 102 or another portion of the first user input 98 to determine user engagement and to generate the engagement input signal ES.

[0075] In some versions, a second user input 106 may in communication with the controller 76 and arranged for user engagement at a different location (e.g., operatively attached to the mobile medical device 28 in a location suitable for user engagement, such as at the head end HE of the support structure 32) and / or by a second, different user. The second user input 106 may be of the same type, style, and / or configuration as the first user input 98, or may be different. The controller 76 may be configured to operate the hub motor 72 based on user engagement with the second user input 106. In some versions, a user may operate the hub motor 72 based on user engagement with only the second user input 106. In some versions, the controller 76 may be configured to operate the hub motor 72 in response to simultaneous user engagement with the first user input 98 and the second user input 106, such as to require the presence of two users where simultaneous user engagement with the first user input 98 and the second user input 106 may be implemented as a safety measure to prevent inadvertent operation of the hub motor 72.

[0076] The second user input 106 may include a second user input control 108 configured to provide a second user input signal IS2 to the controller 76 in response to user engagement with the second user input control 108. The second user input signal IS2 may pertain to at least one of a desired direction for the hub motor 72 to modulate application of torque to the wheel 50, a desired speed for the mobile medical device 28 (e.g. the patient transport apparatus 30) to move along the floor surface F, and the presence of user engagement with the second user input control 108. In these examples, the controller 76 is configured to operate the hub motor 72 based on at least oneof the first user input signal TS1 and the second user input signal IS2. For example, as discussed above, a user may operate the hub motor 72 based on user engagement with only the second user input control 108, or the controller 76 may be configured to operate the hub motor 72 in response to simultaneous user engagement with the first user input control 100 and the second user input control 108. The specific implementation of the second user input control 108 is not particularly limited for the purposes of this disclosure and may include button(s), toggle switch(es), rotary dial(s), slider(s), keyboard(s), touchscreen(s), joystick(s), lever(s), knob(s), throttle(s), foot pedal(s), the like, and combinations thereof.

[0077] The first user input control 100 (e.g., the engagement input control 100c) and / or the second user input control 108 may include a capacitive sensor 110. The capacitive sensor 110 of the second user input control 108 may be configured to generate the second user input signal IS2 in response to the presence of user engagement with the second user input control 108. For example, Figure 6 shows a capacitive sensor 110 arranged on a grip portion of the handle 102 to detect user engagement with the handle 102. Here, the second user input signal IS1 pertains to the presence of user engagement with the second user input control 108, and the controller 76 may be configured to operate the hub motor 72 based on the second user input signal IS2. For example, in order to prevent inadvertent operation of the hub motor 72, the controller 76 may inhibit the hub motor 72 from applying torque unless the second user input control 108 generates the second user input signal IS2 indicating that a user is gripping the handle 102. Exemplary configurations of a handle 102 including a capacitive sensor 1 10 are disclosed in U.S. Patent Application No. 18 / 564,199, filed Nov. 27, 2023, the contents of which are hereby incorporated by reference in its entirety.

[0078] In some versions, the first user input control 100 is spaced from the second user input control 108. For example, as shown in Figure 1, where the mobile medical device 28 is implemented as a patient transport apparatus 30, the first user input control 100 may arranged toward one of the head end HE and the foot end FE of the patient transport apparatus 30 such that the first user input control 100 is arranged for user engagement by a first user, and the second user input control 108 may be arranged towards the other of the head end HE and the foot end FE such that the second user input control 108 is arranged for user engagement by a second user. Here, the controller 76 may be configured to operate the hub motor 72 to modulate application of torque to the wheel 50 in response to simultaneous user engagement with the first user input control 100 by the first user and the second user input control 108 by the second user.

[0079] Referring now to Figures 7A-8B, as noted above, the slip ring 79 may be used in some versions transmit power and / or data to facilitate operation of the hub motor 72 via the controller 76. The slip ring 79 is operatively attached to the powered caster assembly 49 and is configured to establish electrical communication of the hub motor 72 (and / or other components such as various sensors in some versions) with one or more of the controller 76, the power source 78, and / or other components of the control system 74. To this end, the slip ring 79 generally includes a first ring element 112 and a second ring element 114. The first ring element 112 includes one or more first element wires 116, and the second ring element 114 includes one or more second element wires 118. In the illustrated versions, the first ring element 112 supports one or more terminals 93 defined as brushes 120 (see Figure 8B) coupled to respective first element wires 116, and the second ring element 114 supports one or more contacts 95 defined as traces 122 coupled to respective second element wires 118. The one or more traces 122 are arranged for engagement with the one or more brushes 120 to establish electrical communication therebetween(e.g., across the slip ring 79 between the hub motor 72 and one or more of the controller 76 and the power source 78).

[0080] In the representative version illustrated in Figure 8B, the traces 122 are realized as a plurality of annular’ traces 124 which each have generally ring-shaped profiles, are arranged concentrically with each other, and are disposed in spaced relation from each other. Here, each annular trace 124 is arranged for engagement with a corresponding brush 120 to maintain electrical communication between the respective first and second element wires 116, 118. With this configuration, the one or more brushes 120 each maintain engagement with the corresponding one or more annular traces 124 as the wheel support 54 swivels about the swivel axis S. Put differently, in this version, the slip ring 79 maintains electrical communication of the hub motor 72 with one or more of the controller 76 and the power source 78 as the wheel support 54 swivels about the swivel axis S.

[0081] Referring now to Figure 9, in some versions, one or more of the traces 122 may be realized as segmented traces 126 which have profiles that are not circular, and may be interrupted with multiple contact points or a single contact point (not shown). Here, the brush 120 is arranged to be disposed in engagement with the segmented trace 126 during operation of the steer lock assembly 64 in the steer locked state SL based on the indexing of the segmented traces 126 so that engagement does not occur when the powered caster assembly 49 is pivoted about the swivel axis S to a position in which the steer locked state SL is not achievable. With this configuration, the slip ring 79 interrupts electrical communication of the hub motor 72 with one or more of the controller 76 and the power source 78 as the steer lock assembly 64 moves from the steer locked state SL to the non-steer locked state UL.

[0082] Referring now to Figures 10A-10B, in some versions, one portion of the slip ring 79 may be operatively attached to or otherwise formed integrally with the interface plate 71, and another portion of the slip ring 79 may be operatively attached to or otherwise formed integrally with the steer lock pin 67A. In the illustrated version, the first ring element 112 supporting the brush 120 is operatively attached to the steer lock pin 67 A, and the second ring element 114 supporting the traces 122 is operatively attached to the interface plate 71. With this configuration, operation of the steer lock pin 67A in the non-steer locked state UL (see Figure 10A) spaces the first ring element 112 away from the second ring element 114 such that the brushes 120 and traces 122 (or, in some versions, the terminals 93 and the contacts 95; not shown in detail) are disengaged, whereas operation of the steer lock pin 67 A in the steer locked state SL brings the first ring element 112 into abutment with the second ring element 114 such that the brushes 120 and traces 122 (or, in some versions, the terminals 93 and contacts 95) are engaged to facilitate electrical communication.

[0083] In the versions depicted in Figures 7A-10B, the slip ring 79 has a “pancake” configuration. However, other versions are contemplated, and the slip ring 79 could be of various styles, types, and arrangements. For example, in the versions depicted in Figures 11A-12B, the slip ring 79 has a “through bore” configuration. In this version, and as is best depicted in Figure 12B, the traces 122 are likewise provided as ring-shaped annular traces 124 which are disposed in spaced relation from each other, but are of similar size rather than having different diameters (compare Figure 12B with Figure 8B), and are spaced along the steering axis S rather than radially outwardly from it. While not shown in this version, segmented traces 126 can likewise be used in “through bore” configurations, and it will be appreciated that other configurations are contemplated.

[0084] Several configurations have been discussed in the foregoing description. However, the configurations discussed herein are not intended to be exhaustive or limit the invention to any particular’ form. The terminology which has been 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.

[0085] The present disclosure also comprises the following clauses, with specific features laid out in dependent clauses, that may specifically be implemented as described in greater detail with reference to the configurations and drawings above.CLAUSESI. A patient transport apparatus for transporting a patient, the patient transport apparatus comprising: a support structure including: a base defining a head end and a foot end, and a patient support deck operatively attached to the base and defining a patient support surface to support the patient; a powered caster drive system including at least one powered caster assembly operatively attached to the base for facilitating movement of the support structure along a floor surface, the at least one powered caster assembly comprising: a wheel for contacting the floor surface, a wheel support operatively attached to the base and arranged to support the wheel for rotation about a rotational axis and for swiveling about a swivel axis, a steer lock assembly operable between a steer locked state that impedes swiveling of the wheel about the swivel axis, and a non-steer locked state, and a hub motor interposed between the wheel and the wheel support and configured to selectively modulate application of torque to the wheel to facilitate movement of the support structure along the floor surface; and a controller in communication with the powered caster drive system and configured to operate the powered caster drive system;wherein the powered caster drive system is operable between a plurality of states including: a first state to operate the hub motor to selectively modulate application of torque to the wheel of the at least one powered caster assembly during operation of the steer lock assembly in the steer locked state, and a second state to inhibit the hub motor from applying torque to drive the wheel of the at least one powered caster assembly during operation of the steer lock assembly in the non-steer locked state.II. The patient transport apparatus of clause I, wherein the controller is configured to operate the powered caster drive system in the first state in response to determining that the steer lock assembly is in the steer locked state and to operate the powered caster drive system in the second state in response to determining that the steer lock assembly is in the non-steer locked state.III. The patient transport apparatus of clause II, wherein the steer lock assembly further comprises a lock switch in communication with the controller and configured to provide at least one of a locked signal to the controller in response to the steer lock assembly being in the steer locked state and an unlocked signal to the controller in response to the steer lock assembly being in the non-steer locked state.IV. The patient transport apparatus of clause III, wherein the controller is configured to operate the powered caster drive system in the first state in response to receiving the locked signal.V. The patient transport apparatus of any one of clauses III or IV, wherein the controller is configured to operate the powered caster drive system in the second state in response to receiving the unlocked signal.VI. The patient transport apparatus of any one of clauses I to V, further comprising a first user input in communication with the controller and arranged for user engagement, wherein the controller is configured to operate the hub motor based on user engagement with the first user input.VII. The patient transport apparatus of clause VI, wherein the first user input comprises first user input control configured to provide a first user input signal to the controller in response to user engagement with the first user input control, the first user input signal pertaining to at least one of a desired direction for the hub motor to generate torque, a desired speed for the patient transport apparatus to move along the floor surface, and the presence of user engagement with the first user input control; andwherein the controller is configured to operate the hub motor based on the first user input signal.VIII. The patient transport apparatus of clause VII, wherein the first user input control comprises a handle operatively attached to the support structure and configured to be gripped by the user, and a throttle operatively attached to the handle and arranged for movement relative to the handle in response to user engagement; wherein the throttle is configured to generate the first user input signal in response to user engagement with the throttle; and wherein the controller is configured to operate the hub motor based on the first user input signal.IX. The patient transport apparatus of clause VIII, wherein the first user input signal generated by the throttle pertains to the desired speed for the patient transport apparatus to move along the floor surface based on the magnitude of the movement of the throttle relative to the handle.X. The patient transport apparatus of any one of clauses VIII or IX, wherein the first user input signal generated by the throttle pertains to the desired direction for the hub motor to generate torque based on the direction of the movement of the throttle relative to the handle.XI. The patient transport apparatus of any one of clauses VIII to X, wherein the throttle is arranged for user selected rotation relative to the handle about a central axis.XII. The patient transport apparatus of clause VI, wherein the first user input comprises a speed input control configured to provide a speed input signal to the controller based on user engagement with the speed input control, the speed input signal pertaining to a desired speed for the patient transport apparatus to move along the floor surface, and wherein the controller is configured to operate the hub motor based on the speed input signal.XIII. The patient transport apparatus of clause VI, wherein the first user input comprises a direction input control configured to provide a direction input signal to the controller based on user engagement with the direction input control, the direction input signal pertaining to a desired direction for the hub motor to generate torque, and wherein the controller is configured to operate the hub motor based on the direction input signal.XIV. The patient transport apparatus of clause VI, wherein the first user input comprises an engagement input control configured to provide an engagement input signal to the controllerbased on user engagement with the engagement input control, the engagement input signal pertaining to the presence of user engagement with the engagement input control, and wherein the controller is configured to operate the hub motor based on the engagement input signal.XV. The patient transport apparatus of any one of clauses VI to XIV, further comprising a second user input in communication with the controller and arranged for user engagement.XVI. The patient transport apparatus of clause XV, wherein the controller is configured to operate the hub motor to generate torque in response to simultaneous user engagement with the first user input and the second user input.XVII. The patient transport apparatus of any one of clauses XV or XVI, wherein the second user input comprises a second user input control configured to provide a second user input signal to the controller in response to user engagement with the second user input control, the second user input signal pertaining to at least one of a desired direction for the hub motor to generate torque, a desired speed for the patient transport apparatus to move along the floor surface, and the presence of user engagement with the second user input control; and wherein the controller is configured to operate the hub motor based on at least one of the first user input signal and the second user input signal.XVIII. The patient transport apparatus of clause XVII, wherein the second user input signal generated by the second user input control pertains to the presence of user engagement with the second user input control.XIX. The patient transport apparatus of clause XVIII, wherein the second user input control comprises a capacitive sensor configured to generate the second user input signal in response to the presence of user engagement with the second user input control.XX. The patient transport apparatus of any one of clauses XVII to XIX, wherein the first user input control is spaced from the second user input control.XXI. The patient transport apparatus of clause XX, wherein the first user input control is arranged toward one of the head end and the foot end such that the first user input control is arranged for user engagement by a first user, and the second user input control is arranged towards the other of the head end and the foot end such that the second user input control is arranged for user engagement by a second user.XXIT. The patient transport apparatus of clause XXI, wherein the controller is configured to operate the hub motor to generate torque in response to simultaneous user engagement with the first user input control by the first user and the second user input control by the second user.XXIII. The patient transport apparatus of any one of clauses I to XXII, further comprising a speed sensor in communication with the controller and configured to generate a signal representative of the speed of the patient transport apparatus relative to the floor surface, and wherein the controller is configured to adjust the at least one of the torque generated by the hub motor and the speed of the hub motor based on the signal representative of the speed of the patient transport apparatus relative to the floor surface such that the speed of the patient transport apparatus relative to the floor surface does not exceed a pre-defined threshold.XXIV. The patient transport apparatus of any one of clauses I to XXIII, further comprising a power source operatively attached to at least the hub motor for powering the hub motor to generate torque to facilitate movement of the support structure along the floor surface.XXV. The patient transport apparatus of clause XXIV, further comprising a slip ring operatively attached to the powered caster assembly and configured to establish electrical communication of the hub motor with one or more of the controller and the power source.XXVI. The patient transport apparatus of clause XXV, wherein the slip ring maintains electrical communication of the hub motor with one or more of the controller and the power source as the wheel support swivels about the swivel axis.XXVII. The patient transport apparatus of clause XXV, wherein the slip ring interrupts electrical communication of the hub motor with one or more of the controller and the power source as the steer lock assembly moves from the steer locked state to the non-steer locked state.XXVIII. The patient transport apparatus of any one of clauses XXV-XXVII, wherein the slip ring includes: a first ring element supporting a terminal, and a second ring element supporting a contact arranged for engagement with the terminal to establish electrical communication between the terminal and the contact.XXIX. The patient transport apparatus of clause XXVIII, wherein the terminal is further defined as a brush; and wherein the contact is further defined as a trace.XXX. The patient transport apparatus of clause XXTX, wherein the slip ring includes a plurality of brushes and a corresponding plurality of traces.XXXI. The patient transport apparatus of any one of clauses XXIX -XXX, wherein the trace is further defined as an annular trace; and wherein the brush maintains engagement with the annular trace as the wheel support swivels about the swivel axis.XXXII. The patient transport apparatus of any one of clauses XXIX-XXX, wherein the trace is further defined as a segmented trace; and wherein the brush is disposed in engagement with the segmented trace during operation of the steer lock assembly in the steer locked state.XXXIII. The patient transport apparatus of any one of clauses XXIV-XXXII, further comprising an electrical disconnect interposed between the power source and the hub motor, wherein the electrical disconnect is configured to permit electrical communication between the power source and the hub motor where the powered caster drive system is in the first state and to interrupt electrical communication between the power source and the hub motor where the powered caster drive system is in the second state.XXXIV. The patient transport apparatus of clause XXXIII, wherein the electrical disconnect comprises a terminal arranged for movement relative to an electrical contact, wherein the terminal is arranged in electrical communication with the electrical contact where the powered caster drive system is in the first state to permit electrical communication between the power source and the hub motor, and wherein the terminal is spaced from the electrical contact to interrupt electrical communication between the terminal and the electrical contact where the powered caster drive system is in the second state to interrupt electrical communication between the power source and the hub motor.XXXV. The patient transport apparatus of any one of clauses I to XXXIV, wherein the at least one powered caster assembly includes a first powered caster assembly and a second powered caster assembly spaced from the first powered caster assembly.XXXVI. The patient transport apparatus of clause XXXV, wherein the first powered caster assembly is operatively attached to the base at one of the head end and the foot end, and whereinthe second powered caster assembly is operatively attached to the base at the other of the head end and the foot end.XXXVII. The patient transport apparatus of any one of clauses XXXV or XXXVI, wherein the base defines a first lateral side and a second lateral side opposite the first lateral side, and wherein the first powered caster assembly is operatively attached to the base at one of the first lateral side and second lateral side, and wherein the second powered caster assembly is operatively attached to the base at the other of the first lateral side and second lateral side.XXXVIII. The patient transport apparatus of any one of clauses I to XXXVII, wherein the patient transport apparatus defines a longitudinal axis extending between the head end and the foot end, and a vertical axis arranged orthogonal to the longitudinal axis.XXXIX. The patient transport apparatus of clause XXXVIII, wherein the swivel axis is parallel to the vertical axis.XL. The patient transport apparatus of clause XXXVIII, wherein the swivel axis is angularly offset from parallel to the vertical axis by a camber angle.XLI. The patient transport apparatus of any one of clauses XXXVIII to XL, wherein where the steer lock assembly is in the steer locked state, the wheel is arranged such that the rotational axis is orthogonal to the longitudinal axis and the steer lock assembly impedes swiveling of the wheel about the swivel axis.XLII. The patient transport apparatus of any one of clauses XXXVIII to XLI, wherein where the steer lock assembly is in the steer locked state, the wheel is arranged such that the rotational axis is angularly offset from orthogonal to the longitudinal axis by a toe angle and the steer lock assembly impedes swiveling of the wheel about the swivel axis.XLIII. The patient transport apparatus of any one of clauses I to XLII, wherein selectively modulating application of torque to the wheel is further defined as applying a positive torque to the wheel to drive the wheel to facilitate movement of the patient transport apparatus along the floor surface.XLIV. The patient transport apparatus of any one of clauses I to XLIII, wherein selectively modulating application of torque to the wheel is further defined as applying a negative torque to the wheel to brake the wheel and the patient transport apparatus relative to the floor surface.XLV. A powered caster drive system for a mobile medical device for facilitating movement of the mobile medical device along a floor surface, the powered caster drive system comprising: at least one powered caster assembly comprising: a wheel for contacting the floor surface; a wheel support configured to be operatively attached to the mobile medical device and arranged to support the wheel for rotation about a rotational axis and for swiveling about a swivel axis; a steer lock assembly operable between a steer locked state that impedes swiveling of the wheel about the swivel axis, and a non-steer locked state; and a hub motor interposed between the wheel and the wheel support and configured to selectively modulate application of torque to the wheel to facilitate movement of the mobile medical device along the floor surface, a controller in communication with the at least one powered caster assembly and configured to operate the powered caster drive system; wherein the powered caster drive system is operable between a plurality of states including: a first state to operate the hub motor to selectively modulate application of torque to the wheel of the at least one powered caster assembly during operation of the steer lock assembly in the steer locked state, and a second state to inhibit the hub motor from applying torque to drive the wheel of the at least one powered caster assembly during operation of the steer lock assembly in the non-steer locked state.XLVI. The powered caster drive system of clause XLV, wherein the controller is configured to operate the powered caster drive system in the first state in response to determining that the steer lock assembly is in the steer locked state and to operate the powered caster drive system in the second state in response to determining that the steer lock assembly is in the non- steer locked state.XLVII. The powered caster drive system of clause XLVI, wherein the steer lock assembly further comprises a lock switch in communication with the controller and configured to provide at least one of a locked signal to the controller in response to the steer lock assembly being in thesteer locked state and an unlocked signal to the controller in response to the steer lock assembly being in the non-stccr locked state.XLVIII. The powered caster drive system of clause XL VII, wherein the controller is configured to operate the powered caster drive system in the first state in response to receiving the locked signal.XLIX. The powered caster drive system of any one of clauses XLVII or XLVIII, wherein the controller is configured to operate the powered caster drive system in the second state in response to receiving the unlocked signal.L. The powered caster drive system of any one of clauses XLV to XLIX, further comprising a first user input in communication with the controller and configured to be arranged for user engagement, wherein the controller is configured to operate the hub motor based on user engagement with the first user input.LI. The powered caster drive system of clause L, wherein the first user input comprises first user input control configured to provide a first user input signal to the controller in response to user engagement with the first user input control, the first user input signal pertaining to at least one of a desired direction for the hub motor to generate torque, a desired speed for the mobile medical device to move along the floor surface, and the presence of user engagement with the first user input control; and wherein the controller is configured to operate the hub motor based on the first user input signal.LIL The powered caster drive system of clause L, wherein the first user input comprises a speed input control configured to provide a speed input signal to the controller based on user engagement with the speed input control, the speed input signal pertaining to a desired speed for the mobile medical device to move along the floor surface, and wherein the controller is configured to operate the hub motor based on the speed input signal.LIII. The powered caster drive system of clause L, wherein the first user input comprises a direction input control configured to provide a direction input signal to the controller based on user engagement with the direction input control, the direction input signal pertaining to a desired direction for the hub motor to generate torque, and wherein the controller is configured to operate the hub motor based on the direction input signal.LTV. The powered caster drive system of clause L, wherein the first user input comprises an engagement input control configured to provide an engagement input signal to the controller based on user engagement with the engagement input control, the engagement input signal pertaining to the presence of user engagement with the engagement input control, and wherein the controller is configured to operate the hub motor based on the engagement input signal.LV. The powered caster drive system of any one of clauses L to LIV, further comprising a second user input in communication with the controller and configured to be arranged for user engagement.LVI. The powered caster drive system of clause LV, wherein the controller is configured to operate the hub motor to generate torque in response to simultaneous user engagement with the first user input and the second user input.LVII. The powered caster drive system of any one of clauses LV or LVI, wherein the second user input comprises a second user input control configured to provide a second user input signal to the controller in response to user engagement with the second user input control, the second user input signal pertaining to at least one of a desired direction for the hub motor to generate torque, a desired speed for the mobile medical device to move along the floor surface, and the presence of user engagement with the second user input control; and wherein the controller is configured to operate the hub motor based on at least one of the first user input signal and the second user input signal.LVIII. The powered caster drive system of clause LVII, wherein the first user input control is spaced from the second user input control.LIX. The powered caster drive system of clause LVIII, wherein the controller is configured to operate the hub motor to generate torque in response to simultaneous user engagement with the first user input control by a first user and the second user input control by a second user.LX. The powered caster drive system of any one of clauses XLV to LIX, further comprising a speed sensor in communication with the controller and configured to generate a signal representative of the speed of the mobile medical device relative to the floor surface, and wherein the controller is configured to adjust the at least one of the torque generated by the hub motor and the speed of the hub motor based on the signal representative of the speed of the mobile medical device relative to the floor surface such that the speed of the mobile medical device relative to the floor surface does not exceed a pre-defined threshold.LXL The powered caster drive system of any one of clauses XLV to LX, further comprising a power source operatively attached to at least the hub motor for powering the hub motor to generate torque to facilitate movement of the mobile medical device along the floor surface.LXII. The powered caster drive system of clause LXI, further comprising a slip ring operatively attached to the powered caster assembly and configured to establish electrical communication of the hub motor with one or more of the controller and the power source.LXIII. The powered caster drive system of clause LXII, wherein the slip ring maintains electrical communication of the hub motor with one or more of the controller and the power source as the wheel support swivels about the swivel axis.LXIV. The powered caster drive system of clause LXII, wherein the slip ring interrupts electrical communication of the hub motor with one or more of the controller and the power source as the steer lock assembly moves from the steer locked state to the non-steer locked state.LXV. The powered caster drive system of any one of clauses LXII-LXIV, wherein the slip ring includes: a first ring element supporting a terminal, and a second ring element supporting a contact arranged for engagement with the terminal to establish electrical communication between the terminal and the contact.LXVI. The powered caster drive system of clause LXV, wherein the terminal is further defined as a brush; and wherein the contact is further defined as a trace.LXVII. The powered caster drive system of clause LXVI, wherein the slip ring includes a plurality of brushes and a corresponding plurality of traces.LXVIII. The powered caster drive system of any one of clauses LXVI-LXVII, wherein the trace is further defined as an annular trace; and wherein the brush maintains engagement with the annular trace as the wheel support swivels about the swivel axis.LXIX. The powered caster drive system of any one of clauses LXVI-LXVII, wherein the trace is further defined as a segmented trace; and wherein the brush is disposed in engagement with the segmented trace during operation of the steer lock assembly in the steer locked state.LXX. The powered caster drive system of any one of clauses LXI-LXIX, further comprising an electrical disconnect interposed between the power source and the hub motor, wherein the electrical disconnect is configured to permit electrical communication between the power source and the hub motor where the powered caster drive system is in the first state and to interrupt electrical communication between the power source and the hub motor where the powered caster drive system is in the second state.LXXI. The powered caster drive system of clause LXX, wherein the electrical disconnect comprises a terminal arranged for movement relative to an electrical contact, wherein the terminal is arranged in electrical communication with the electrical contact where the powered caster drive system is in the first state to permit electrical communication between the power source and the hub motor, and wherein the terminal is spaced from the electrical contact to interrupt electrical communication between the terminal and the electrical contact where the powered caster drive system is in the second state to interrupt electrical communication between the power source and the hub motor.LXXII. The powered caster drive system of any one of clauses XLV to LXXI, wherein selectively modulating application of torque to the wheel is further defined as applying a positive torque to the wheel to drive the wheel to facilitate movement of the mobile medical device along the floor surface.LXXIII. The powered caster drive system of any one of clauses XLV to LXXII, wherein selectively modulating application of torque to the wheel is further defined as applying a negative torque to the wheel to brake the wheel and the mobile medical device relative to the floor surface.

Claims

CLAIMSWhat is claimed is:

1. A patient transport apparatus for transporting a patient, the patient transport apparatus comprising: a support structure including: a base defining a head end and a foot end, and a patient support deck operatively attached to the base and defining a patient support surface to support the patient; a powered caster drive system including at least one powered caster assembly operatively attached to the base for facilitating movement of the support structure along a floor surface, the at least one powered caster assembly comprising: a wheel for contacting the floor surface, a wheel support operatively attached to the base and arranged to support the wheel for rotation about a rotational axis and for swiveling about a swivel axis, a steer lock assembly operable between a steer locked state that impedes swiveling of the wheel about the swivel axis, and a non-steer locked state, and a hub motor interposed between the wheel and the wheel support and configured to selectively modulate application of torque to the wheel to facilitate movement of the support structure along the floor surface; and a controller in communication with the powered caster drive system and configured to operate the powered caster drive system; wherein the powered caster drive system is operable between a plurality of states including: a first state to operate the hub motor to selectively modulate application of torque to the wheel of the at least one powered caster assembly during operation of the steer lock assembly in the steer locked state, and a second state to inhibit the hub motor from applying torque to drive the wheel of the at least one powered caster assembly during operation of the steer lock assembly in the non-steer locked state.

2. The patient transport apparatus of claim 1 , wherein the controller is configured to operate the powered caster drive system in the first state in response to determining that the steer lock assembly is in the steer locked state and to operate the powered caster drive system in the second state in response to determining that the steer lock assembly is in the non-steer locked state.

3. The patient transport apparatus of claim 2, wherein the steer lock assembly further comprises a lock switch in communication with the controller and configured to provide at least one of a locked signal to the controller in response to the steer lock assembly being in the steer locked state and an unlocked signal to the controller in response to the steer lock assembly being in the non-steer locked state.

4. The patient transport apparatus of claim 3, wherein the controller is configured to operate the powered caster drive system in the first state in response to receiving the locked signal.

5. The patient transport apparatus of claim 3, wherein the controller is configured to operate the powered caster drive system in the second state in response to receiving the unlocked signal.

6. The patient transport apparatus of claim 1, further comprising a first user input in communication with the controller and arranged for user engagement, wherein the controller is configured to operate the hub motor based on user engagement with the first user input.

7. The patient transport apparatus of claim 6, wherein the first user input comprises first user input control configured to provide a first user input signal to the controller in response to user engagement with the first user input control, the first user input signal pertaining to at least one of a desired direction for the hub motor to generate torque, a desired speed for the patient transport apparatus to move along the floor surface, and the presence of user engagement with the first user input control; and wherein the controller is configured to operate the hub motor based on the first user input signal.

8. The patient transport apparatus of claim 7, wherein the first user input control comprises a handle operatively attached to the support structure and configured to be gripped by the user, and a throttle operatively attached to the handle and arranged for movement relative to the handle in response to user engagement; wherein the throttle is configured to generate the first user input signal in response to user engagement with the throttle; and wherein the controller is configured to operate the hub motor based on the first user input signal.

9. The patient transport apparatus of claim 8, wherein the first user input signal generated by the throttle pertains to the desired speed for the patient transport apparatus to move along the floor surface based on the magnitude of the movement of the throttle relative to the handle.

10. The patient transport apparatus of claim 8, wherein the first user input signal generated by the throttle pertains to the desired direction for the hub motor to generate torque based on the direction of the movement of the throttle relative to the handle.

11. The patient transport apparatus of claim 8, wherein the throttle is arranged for user selected rotation relative to the handle about a central axis.

12. The patient transport apparatus of claim 6, wherein the first user input comprises a speed input control configured to provide a speed input signal to the controller based on user engagement with the speed input control, the speed input signal pertaining to a desired speed for the patient transport apparatus to move along the floor surface, and wherein the controller is configured to operate the hub motor based on the speed input signal.

13. The patient transport apparatus of claim 6, wherein the first user input comprises a direction input control configured to provide a direction input signal to the controller based on user engagement with the direction input control, the direction input signal pertaining to a desired direction for the hub motor to generate torque, and wherein the controller is configured to operate the hub motor based on the direction input signal.

14. The patient transport apparatus of claim 6, wherein the first user input comprises an engagement input control configured to provide an engagement input signal to the controller based on user engagement with the engagement input control, the engagement input signal pertaining to the presence of user engagement with the engagement input control, and wherein the controller is configured to operate the hub motor based on the engagement input signal.

15. The patient transport apparatus of claim 6, further comprising a second user input in communication with the controller and arranged for user engagement.

16. The patient transport apparatus of claim 15, wherein the controller is configured to operate the hub motor to generate torque in response to simultaneous user engagement with the first user input and the second user input.

17. The patient transport apparatus of claim 15, wherein the second user input comprises a second user input control configured to provide a second user input signal to the controller in response to user engagement with the second user input control, the second user input signal pertaining to at least one of a desired direction for the hub motor to generate torque, a desired speed for the patient transport apparatus to move along the floor surface, and the presence of user engagement with the second user input control; and wherein the controller is configured to operate the hub motor based on at least one of the first user input signal and the second user input signal.

18. The patient transport apparatus of claim 17, wherein the second user input signal generated by the second user input control pertains to the presence of user engagement with the second user input control.

19. The patient transport apparatus of claim 18, wherein the second user input control comprises a capacitive sensor configured to generate the second user input signal in response to the presence of user engagement with the second user input control.

20. The patient transport apparatus of claim 17, wherein the first user input control is spaced from the second user input control.

21. The patient transport apparatus of claim 20, wherein the first user input control is arranged toward one of the head end and the foot end such that the first user input control is arranged for user engagement by a first user, and the second user input control is arranged towards the other of the head end and the foot end such that the second user input control is arranged for user engagement by a second user.

22. The patient transport apparatus of claim 21, wherein the controller is configured to operate the hub motor to generate torque in response to simultaneous user engagement with the first user input control by the first user and the second user input control by the second user.

23. The patient transport apparatus of claim 1, further comprising a speed sensor in communication with the controller and configured to generate a signal representative of the speed of the patient transport apparatus relative to the floor surface, and wherein the controller is configured to adjust the at least one of the torque generated by the hub motor and the speed of the hub motor based on the signal representative of the speed of the patient transport apparatus relative to the floor surface such that the speed of the patient transport apparatus relative to the floor surface does not exceed a pre-defined threshold.

24. The patient transport apparatus of claim 1, further comprising a power source operatively attached to at least the hub motor for powering the hub motor to generate torque to facilitate movement of the support structure along the floor surface.

25. The patient transport apparatus of claim 24, further comprising a slip ring operatively attached to the powered caster assembly and configured to establish electrical communication of the hub motor with one or more of the controller and the power source.

26. The patient transport apparatus of claim 25, wherein the slip ring maintains electrical communication of the hub motor with one or more of the controller and the power source as the wheel support swivels about the swivel axis.

27. The patient transport apparatus of claim 25, wherein the slip ring interrupts electrical communication of the hub motor with one or more of the controller and the power source as the steer lock assembly moves from the steer locked state to the non-steer locked state.

28. The patient transport apparatus of claim 25, wherein the slip ring includes: a first ring element supporting a terminal, and a second ring element supporting a contact arranged for engagement with the terminal to establish electrical communication between the terminal and the contact.

29. The patient transport apparatus of claim 28, wherein the terminal is further defined as a brush; and wherein the contact is further defined as a trace.

30. The patient transport apparatus of claim 29, wherein the slip ring includes a plurality of brushes and a corresponding plurality of traces.

31. The patient transport apparatus of claim 29, wherein the trace is further defined as an annular trace; and wherein the brush maintains engagement with the annular trace as the wheel support swivels about the swivel axis.

32. The patient transport apparatus of claim 29, wherein the trace is further defined as a segmented trace; and wherein the brush is disposed in engagement with the segmented trace during operation of the steer lock assembly in the steer locked state.

33. The patient transport apparatus of claim 24, further comprising an electrical disconnect interposed between the power source and the hub motor, wherein the electrical disconnect is configured to permit electrical communication between the power source and the hub motor where the powered caster drive system is in the first state and to interrupt electrical communication between the power source and the hub motor where the powered caster drive system is in the second state.

34. The patient transport apparatus of claim 33, wherein the electrical disconnect comprises a terminal arranged for movement relative to an electrical contact, wherein the terminal is arranged in electrical communication with the electrical contact where the powered caster drive system is in the first state to permit electrical communication between the power source and the hub motor, and wherein the terminal is spaced from the electrical contact to interrupt electrical communication between the terminal and the electrical contact where the powered caster drive system is in the second state to interrupt electrical communication between the power source and the hub motor.

35. The patient transport apparatus of claim 1, wherein the at least one powered caster assembly includes a first powered caster assembly and a second powered caster assembly spaced from the first powered caster assembly.

36. The patient transport apparatus of claim 35, wherein the first powered caster assembly is operatively attached to the base at one of the head end and the foot end, and wherein the second powered caster assembly is operatively attached to the base at the other of the head end and the foot end.

37. The patient transport apparatus of claim 35, wherein the base defines a first lateral side and a second lateral side opposite the first lateral side, and wherein the first powered caster assembly is operatively attached to the base at one of the first lateral side and second lateral side, and wherein the second powered caster assembly is operatively attached to the base at the other of the first lateral side and second lateral side.

38. The patient transport apparatus of claim 1 , wherein the patient transport apparatus defines a longitudinal axis extending between the head end and the foot end, and a vertical axis arranged orthogonal to the longitudinal axis.

39. The patient transport apparatus of claim 38, wherein the swivel axis is parallel to the vertical axis.

40. The patient transport apparatus of claim 38, wherein the swivel axis is angularly offset from parallel to the vertical axis by a camber angle.

41. The patient transport apparatus of claim 38, wherein where the steer lock assembly is in the steer locked state, the wheel is arranged such that the rotational axis is orthogonal to the longitudinal axis and the steer lock assembly impedes swiveling of the wheel about the swivel axis.

42. The patient transport apparatus of claim 38, wherein where the steer lock assembly is in the steer locked state, the wheel is arranged such that the rotational axis is angularly offset from orthogonal to the longitudinal axis by a toe angle and the steer lock assembly impedes swiveling of the wheel about the swivel axis.

43. The patient transport apparatus of claim 1, wherein selectively modulating application of torque to the wheel is further defined as applying a positive torque to the wheel to drive the wheel to facilitate movement of the patient transport apparatus along the floor surface.

44. The patient transport apparatus of claim 1, wherein selectively modulating application of torque to the wheel is further defined as applying a negative torque to the wheel to brake the wheel and the patient transport apparatus relative to the floor surface.

45. A powered caster drive system for a mobile medical device for facilitating movement of the mobile medical device along a floor surface, the powered caster drive system comprising: at least one powered caster assembly comprising:a wheel for contacting the floor surface; a wheel support configured to be operatively attached to the mobile medical device and arranged to support the wheel for rotation about a rotational axis and for swiveling about a swivel axis; a steer lock assembly operable between a steer locked state that impedes swiveling of the wheel about the swivel axis, and a non-steer locked state; and a hub motor interposed between the wheel and the wheel support and configured to selectively modulate application of torque to the wheel to facilitate movement of the mobile medical device along the floor surface, a controller in communication with the at least one powered caster assembly and configured to operate the powered caster drive system; wherein the powered caster drive system is operable between a plurality of states including: a first state to operate the hub motor to selectively modulate application of torque to the wheel of the at least one powered caster assembly during operation of the steer lock assembly in the steer locked state, and a second state to inhibit the hub motor from applying torque to drive the wheel of the at least one powered caster assembly during operation of the steer lock assembly in the non-steer locked state.

46. The powered caster drive system of claim 45, wherein the controller is configured to operate the powered caster drive system in the first state in response to determining that the steer lock assembly is in the steer locked state and to operate the powered caster drive system in the second state in response to determining that the steer lock assembly is in the non-steer locked state.

47. The powered caster drive system of claim 46, wherein the steer lock assembly further comprises a lock switch in communication with the controller and configured to provide at least one of a locked signal to the controller in response to the steer lock assembly being in the steer locked state and an unlocked signal to the controller in response to the steer lock assembly being in the non-steer locked state.

48. The powered caster drive system of claim 47, wherein the controller is configured to operate the powered caster drive system in the first state in response to receiving the locked signal.

49. The powered caster drive system of claim 47, wherein the controller is configured to operate the powered caster drive system in the second state in response to receiving the unlocked signal.

50. The powered caster drive system of claim 45, further comprising a first user input in communication with the controller and configured to be arranged for user engagement, wherein the controller is configured to operate the hub motor based on user engagement with the first user input.

51. The powered caster drive system of claim 50, wherein the first user input comprises first user input control configured to provide a first user input signal to the controller in response to user engagement with the first user input control, the first user input signal pertaining to at least one of a desired direction for the hub motor to generate torque, a desired speed for the mobile medical device to move along the floor surface, and the presence of user engagement with the first user input control; and wherein the controller is configured to operate the hub motor based on the first user input signal.

52. The powered caster drive system of claim 50, wherein the first user input comprises a speed input control configured to provide a speed input signal to the controller based on user engagement with the speed input control, the speed input signal pertaining to a desired speed for the mobile medical device to move along the floor surface, and wherein the controller is configured to operate the hub motor based on the speed input signal.

53. The powered caster drive system of claim 50, wherein the first user input comprises a direction input control configured to provide a direction input signal to the controller based on user engagement with the direction input control, the direction input signal pertaining to a desireddirection for the hub motor to generate torque, and wherein the controller is configured to operate the hub motor based on the direction input signal.

54. The powered caster drive system of claim 50, wherein the first user input comprises an engagement input control configured to provide an engagement input signal to the controller based on user engagement with the engagement input control, the engagement input signal pertaining to the presence of user engagement with the engagement input control, and wherein the controller is configured to operate the hub motor based on the engagement input signal.

55. The powered caster drive system of claim 50, further comprising a second user input in communication with the controller and configured to be arranged for user engagement.

56. The powered caster drive system of claim 55, wherein the controller is configured to operate the hub motor to generate torque in response to simultaneous user engagement with the first user input and the second user input.

57. The powered caster drive system of claim 55, wherein the second user input comprises a second user input control configured to provide a second user input signal to the controller in response to user engagement with the second user input control, the second user input signal pertaining to at least one of a desired direction for the hub motor to generate torque, a desired speed for the mobile medical device to move along the floor surface, and the presence of user engagement with the second user input control; and wherein the controller is configured to operate the hub motor based on at least one of the first user input signal and the second user input signal.

58. The powered caster drive system of claim 57, wherein the first user input control is spaced from the second user input control.

59. The powered caster drive system of claim 58, wherein the controller is configured to operate the hub motor to generate torque in response to simultaneous user engagement with the first user input control by a first user and the second user input control by a second user.

60. The powered caster drive system of claim 45, further comprising a speed sensor in communication with the controller and configured to generate a signal representative of the speed of the mobile medical device relative to the floor surface, and wherein the controller is configured to adjust the at least one of the torque generated by the hub motor and the speed of the hub motor based on the signal representative of the speed of the mobile medical device relative to the floor surface such that the speed of the mobile medical device relative to the floor surface does not exceed a pre-defined threshold.

61. The powered caster drive system of claim 45, further comprising a power source operatively attached to at least the hub motor for powering the hub motor to generate torque to facilitate movement of the mobile medical device along the floor surface.

62. The powered caster drive system of claim 61 , further comprising a slip ring operatively attached to the powered caster assembly and configured to establish electrical communication of the hub motor with one or more of the controller and the power source.

63. The powered caster drive system of claim 62, wherein the slip ring maintains electrical communication of the hub motor with one or more of the controller and the power source as the wheel support swivels about the swivel axis.

64. The powered caster drive system of claim 62, wherein the slip ring interrupts electrical communication of the hub motor with one or more of the controller and the power source as the steer lock assembly moves from the steer locked state to the non-steer locked state.

65. The powered caster drive system of claim 62, wherein the slip ring includes: a first ring element supporting a terminal, and a second ring element supporting a contact arranged for engagement with the terminal to establish electrical communication between the terminal and the contact.

66. The powered caster drive system of claim 65, wherein the terminal is further defined as a brush; andwherein the contact is further defined as a trace.

67. The powered caster drive system of claim 66, wherein the slip ring includes a plurality of brushes and a corresponding plurality of traces.

68. The powered caster drive system of claim 66, wherein the trace is further defined as an annular trace; and wherein the brush maintains engagement with the annular trace as the wheel support swivels about the swivel axis.

69. The powered caster drive system of claim 66, wherein the trace is further defined as a segmented trace; and wherein the brush is disposed in engagement with the segmented trace during operation of the steer lock assembly in the steer locked state.

70. The powered caster drive system of claim 61, further comprising an electrical disconnect interposed between the power source and the hub motor, wherein the electrical disconnect is configured to permit electrical communication between the power source and the hub motor where the powered caster drive system is in the first state and to interrupt electrical communication between the power source and the hub motor where the powered caster drive system is in the second state.

71. The powered caster drive system of claim 70, wherein the electrical disconnect comprises a terminal arranged for movement relative to an electrical contact, wherein the terminal is arranged in electrical communication with the electrical contact where the powered caster drive system is in the first state to permit electrical communication between the power source and the hub motor, and wherein the terminal is spaced from the electrical contact to interrupt electrical communication between the terminal and the electrical contact where the powered caster drive system is in the second state to interrupt electrical communication between the power source and the hub motor.

72. The powered caster drive system of claim 45, wherein selectively modulating application of torque to the wheel is further defined as applying a positive torque to the wheel to drive the wheel to facilitate movement of the mobile medical device along the floor surface.

73. The powered caster drive system of claim 45, wherein selectively modulating application of torque to the wheel is further defined as applying a negative torque to the wheel to brake the wheel and the mobile medical device relative to the floor surface.

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