Patient transport device with electromechanical brake system

Abstract

A patient transport device includes a base, a patient support platform, a plurality of wheels, a plurality of brakes and an electromechanical brake system. The electromechanical brake system includes a linkage mechanism, a manual actuator and an electric brake assembly. The linkage mechanism is operatively connected to the brake to place the brake in a braking state, a released state or other state. The manual actuator manually moves the linkage mechanism to place the brake in one of the states. The electric brake assembly includes an actuator assembly that uses electricity to move the linkage mechanism to place the brake in one of the states.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and all benefits of U.S. Provisional Patent Application No. 62 / 954,765, filed on December 30, 2019. Background Art

[0003] Patient transport devices, such as hospital beds, stretchers, cribs, wheelchairs, and transfer chairs, facilitate patient care in healthcare settings. Conventional patient transport devices include a support structure having a patient support platform on which the patient is supported, wheels that enable the patient transport device to move along the floor, and a brake system having brakes to stop movement of the patient transport device.

[0004] At least some known brake systems include a manual riser mounted to a support structure to engage or disengage the brake member. Electric brake systems for engaging and disengaging the brake member are also known. Typically, the brake system includes a linkage mechanism having a plurality of connecting rods, wherein each connecting rod is operatively coupled to the brake member so that the movement of one connecting rod causes the movement of the other connecting rods and the corresponding engagement or disengagement of all the brake members. During operation, there may be difficulties associated with connecting, protecting and / or supporting the movement of the connecting rods and / or guiding the connecting rods. There may also be difficulties in connecting the linkage mechanism to a manual or electric actuator, determining the current state of the brake system and / or ensuring that the brake member is fully engaged or fully disengaged.

[0005] There is a need for a patient transport device with a braking system that addresses one or more of the above-mentioned challenges. Summary of the invention

[0006] The present disclosure relates to a patient transport device, which includes a support structure having a base and a patient support platform. A plurality of wheels are connected to the support structure, and a plurality of brakes are arranged to brake the wheels. A linkage mechanism is operatively connected to the plurality of brakes and can be operated between: a braking state, which is used to brake the plurality of wheels; and a release state, which is used to release the plurality of wheels. The linkage mechanism has a first link and a second link, the first link rotates to move the plurality of brakes between the braking state and the release state, and the second link slides to move the plurality of brakes between the braking state and the release state. A retainer is connected to the support structure and cooperates with the linkage mechanism to limit the movement of the linkage mechanism. The retainer has a stopper and a guide, the stopper is used to engage the first link to limit the movement of the first link, and the guide is used to receive the second link to limit the movement of the second link.

[0007] The present disclosure also relates to a patient transport device, which includes a support structure having a base and a patient support platform. A plurality of wheels are connected to the support structure, and a plurality of brakes are arranged to brake the wheels. A linkage mechanism is operatively connected to the plurality of brakes and can be operated between: a braking state, which is used to brake the plurality of wheels; and a release state, which is used to release the plurality of wheels. A position sensor responds to the operation of the linkage mechanism to determine whether the linkage mechanism is in a braking state or a release state. A sensor actuator is connected to the linkage mechanism to move between the braking state and the release state with the linkage mechanism. The sensor actuator has an actuation head and a coupling interface, the actuation head is supported by the support structure to move relative to the position sensor, and the coupling interface is carried by the linkage mechanism to move with the linkage mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a perspective view of a patient transport device.

[0009] Figure 2 is a perspective view of a portion of a patient transport apparatus showing an electromechanical braking system.

[0010] Figure 3 is another perspective view of the portion of the patient transport apparatus showing the electromechanical braking system.

[0011] Figure 4 is a top view of the portion of the patient transport device showing the electromechanical braking system.

[0012] Figure 5A is a cross-sectional view of a caster assembly that can be used with an electromechanical braking system, wherein the brake member is in a braking state.

[0013] Figure 5B is a cross-sectional view of a caster assembly that may be used with an electromechanical braking system, with the brake in a released state.

[0014] Figures 6A-6C is a close-up perspective view of a portion of an electromechanical brake system in a released state, a braked state, and a steering locked state, respectively.

[0015] Figure 7 It is a partially exploded perspective view of multiple parts of the linkage mechanism of the electromechanical brake system.

[0016] Figure 8 is a cross-sectional perspective view of a manual actuator of an electromechanical brake system.

[0017] Fig. 9A It is an exploded perspective view of the electric connecting rod and drive components.

[0018] Fig. 9Bis another exploded perspective view of the electric connecting rod and the driving component.

[0019] Fig.10 It is a perspective view of the electric connecting rod and driving components.

[0020] Fig.11 It is a cross-sectional perspective view of the electric connecting rod and driving components.

[0021] Fig.11A is a top view of the motor and drive shaft arrangement showing the sensor and magnets.

[0022] Fig. 12A is a partially exploded perspective view showing a retainer for the linkage mechanism.

[0023] Fig. 12B is another partially exploded perspective view showing a retainer for the linkage mechanism.

[0024] Fig.13 is a cross-sectional perspective view of a retainer engaged with a linkage mechanism.

[0025] Fig.14 is a partially exploded perspective view showing the connection of a caster stem to a bumper, the caster stem having an octagonal feature.

[0026] Fig.15 is a perspective view showing a caster rod connected to a bumper.

[0027] Fig.16 is a perspective view showing a link supporter supporting the first link.

[0028] Fig.17 is a cross-sectional perspective view showing a link supporter supporting the first link.

[0029] Fig.18 is a block diagram of the components of an electromechanical brake system.

[0030] Fig.19 is a top view of the sensor actuator coupled to the linkage and the bumper.

[0031] Fig. 20 is a perspective view showing a cross section of the rails spanning the bumper rail and the head rail.

[0032] Fig.21 is a top view of the switch engaged by the sensor actuator.

[0033] Fig. 22 is a perspective view of the sensor actuator.

[0034] Fig.23 is another perspective view of the sensor actuator.

[0035] Fig.24 is a cross-sectional perspective view showing a connector for an actuation head of a sensor actuator.

[0036] Fig.25 is an illustration of a sector gear reaching the hard stop limit in an elongated slotted hole.

[0037] 26 is a graph of the duty cycle of a control scheme for an electromechanical braking system over time. DETAILED DESCRIPTION

[0038] refer to Figure 1 , a patient transport device 30 for supporting a patient in a healthcare environment is shown. Figure 1 The patient transport device 30 shown is a hospital bed. However, in other embodiments, the patient transport device 30 may be a stretcher, a crib, a wheelchair, a transport chair, or a similar device for caring for a patient.

[0039] Support structure 32 provides support for the patient. Figure 1 The support structure 32 shown in the figure includes a base 34 and a support frame 36. The base 34 includes a base frame 35. The support frame 36 is Figure 1 36. The support structure 32 also includes a patient support platform 38 disposed on the support frame 36. The patient support platform 38 includes several portions, some of which are articulated (e.g., pivotable) relative to the support frame 36, such as a fowler portion 41, a seat portion 43, a leg portion 45, and a foot portion 47. The patient support platform 38 provides a patient support surface 42 on which the patient is supported.

[0040] During use, a mattress (not shown) is disposed on the patient support platform 38. The mattress includes a second patient support surface on which the patient is supported. The base 34, support frame 36, patient support platform 38 and patient support surface 42 each have a head end and a foot end corresponding to the designated position of the patient's head and feet on the patient transport device 30. The base 34 includes a longitudinal axis L1 along its length from the head end to the foot end. The base 34 also includes a vertical axis V, which is arranged crosswise (e.g., vertically) with the longitudinal axis L1, and the support frame 36 is raised and lowered relative to the base 34 along the vertical axis V. The structure of the support structure 32 can adopt any known or conventional design and is not limited to the situation specifically described above. In addition, in some embodiments, the mattress can be omitted so that the patient rests directly on the patient support surface 42.

[0041] Patient side guards such as lateral rails 44, 46, 48, 50 are coupled to the support frame 36 and / or the patient support platform 38 and are thereby supported by the base 34. The first lateral rail 44 is positioned at the right head end. The second lateral rail 46 is positioned at the right foot end. The third lateral rail 48 is positioned at the left head end. The fourth lateral rail 50 is positioned at the left foot end. In the illustrated embodiment, the head end lateral rails 44, 48 are mounted to the backrest portion 41 to move with the backrest portion 41. The foot end lateral rails 46, 50 are mounted to the support frame 36 to move with the support frame 36. If the patient transport device 30 is a stretcher or a crib, there may be fewer lateral rails. The lateral rails 44, 46, 48, 50 are movable relative to the backrest portion 41 / support frame 36 to a raised position, one or more intermediate positions, and a lower position in which they prevent entry and exit of the patient transport device 30 and in which they do not become an obstacle to such entry and exit. In the illustrated embodiment, the side rails 44, 46, 48, 50 are connected to the backrest portion 41 and / or the support frame 36 via pivoting support arms to form a four-bar linkage. Such side rails and the manner in which they can be raised / lowered are shown and described in U.S. Patent Application Publication No. 2017 / 0172829, filed on December 15, 2016, entitled "Powered Side Rail For A Patient Support Apparatus," which is incorporated herein by reference in its entirety.

[0042] The headboard 52 and risers 54 are coupled to the support frame 36. The headboard 52 and risers 54 may be coupled to any location on the patient transport apparatus 30, such as the support frame 36 or the base 34. In other embodiments, the patient transport apparatus 30 does not include a headboard 52 and / or risers 54.

[0043] A caregiver interface 56 (e.g., handles) is shown integrated into the headboard 52, risers 54, and lateral rails 44, 46, 48, 50 to facilitate movement of the patient transport apparatus 30 over a floor surface. Additional caregiver interfaces 56 may be integrated into other components of the patient transport apparatus 30. The caregiver interface 56 may be grasped by a caregiver to manipulate movement of the patient transport apparatus 30, to move the lateral rails 44, 46, 48, 50, etc.

[0044] Other forms of caregiver interfaces 56 are also contemplated. The caregiver interface may include one or more handles coupled to the support frame 36. The caregiver interface may simply be a surface on the patient transport device 30 on which the caregiver logically applies force to cause the patient transport device 30 to move in one or more directions, also referred to as a push position. This may include one or more surfaces on the support frame 36 or the base 34. This may also include one or more surfaces on or near the headboard 52, risers 54, and / or lateral rails 44, 46, 48, 50. In other embodiments, the caregiver interface may include separate handles for each hand of the caregiver. For example, the caregiver interface may include two handles.

[0045] The mobile device is coupled to the base 34 to facilitate transport on a floor surface. The mobile device includes a plurality of wheels 58. The wheels 58 are arranged in each of the four quadrants of the base 34, adjacent to the corners of the base 34. In the illustrated embodiment, the wheels 58 are casters that are capable of rotating and swivel relative to the support structure 32 during transport. Each wheel 58 forms part of a caster assembly 60. Each caster assembly 60 is mounted to the base 34 and includes a brake 62 to brake the wheel 58 (an example of which is shown in FIG. Figure 5A-5B ). It should be understood that various configurations of caster assemblies 60 are contemplated. Furthermore, in some embodiments, wheels 58 are not casters and may be non-steerable, steerable, non-powered, powered, or a combination thereof. Additional wheels are also contemplated. For example, the patient transport device 30 may include four non-powered non-steerable wheels and one or more powered wheels. In some cases, the patient transport device 30 may not include any wheels.

[0046] In other embodiments, one or more auxiliary wheels (powered or non-powered) movable between the stowed position and the deployed position may be coupled to the support structure 32. In some cases, when these auxiliary wheels are positioned between the caster assemblies 60 and contact the floor surface in the deployed position, they cause two of the caster assemblies 60 to be lifted off the floor surface, thereby shortening the wheelbase of the patient transport apparatus 30. A fifth wheel may also be disposed approximately in the center of the base 34.

[0047] refer to Figure 2-4 The patient transport device 30 includes an electromechanical brake system 64 to enable a user (e.g., a caregiver) to selectively engage or disengage brakes 62 associated with the wheels 58. Figure 2-4, wherein the support frame 36 and the patient support platform 38 are removed for illustration purposes. It should be understood that in the illustrated embodiment, each wheel 58 has an associated brake 62, but in some versions, not all wheels 58 may have an associated brake 62, for example, only one, two, or three of the four wheels 58 may have an associated brake 62. In some versions, the electromechanical brake system 64 may include a plurality of brakes 62 (e.g., two, three, four, etc.) arranged to brake the wheels 58.

[0048] The electromechanical brake system 64 includes a linkage 66 operatively coupled to the brake member 62, a manual actuator 68 coupled to the linkage 66, and an electric brake assembly 70 coupled to the linkage 66. The linkage 66 is configured to move in response to actuation via the manual actuator 68 or the electric brake assembly 70 to operate the brake member 62, as further described below.

[0049] like Figure 4 As shown, the linkage mechanism 66 includes a pair of first links 72. In some embodiments, each of the first links 72 includes an elongated shaft having a hexagonal cross-sectional shape. The first links 72 may also be referred to as hexagonal shafts. The first links 72 extend longitudinally and generally parallel to the longitudinal axis L1 from the head end of the patient transport device 30 to the foot end of the patient transport device 30. The first links 72 are rotatably supported by the base 34 to rotate about their axes. For example, the first links 72 may be rotatably supported in the caster housing CH or other brackets of the base 34 via bushings B, bearings, etc. (the caster housing CH is in Figure 4 denoted by a dotted line).

[0050] The linkage mechanism 66 also includes a pair of second links 74 that are laterally arranged at each of the head end and the foot end. In some embodiments, the second links 74 include a rack driven by a gear as further described below. The second links 74 are supported by the base 34 to slide laterally relative to the base 34. Each of the second links 74 is operatively coupled to the two first links 72 so that the movement of any one of the second links 74 causes the corresponding movement of the two first links 72 and the movement of the other of the second links 74. In other words, the first links 72 and the second links 74 are operatively interconnected so that the movement of any one of the links 72, 74 causes the movement of the other links 72, 74. For example, one of the second links 74 is used to slide the second links 74 via the movement of the manual actuator 68 or the electric brake assembly 70, so that the two first links 72 are rotated to operate the brake member 62.

[0051] In the illustrated embodiment, the linkage mechanism 66 is arranged and operable to place the brake member 62 in the braking state ( Figure 5A shown) and released state ( Figure 5B ), in the braking state, each brake member 62 is used to brake the movement of the corresponding wheel 58, and in the released state, each brake member 62 is released so as not to brake the wheel 58. The released state may also be referred to as a neutral state. The linkage 66 may also be coupled to one or more steering lock mechanisms (not shown) to place the one or more steering lock mechanisms in a steering lock state, in which one or more of the wheels 58 are prevented from rotating, while the other wheels 58 remain able to rotate.

[0052] like Figure 5A and Figure 5B As shown, in some embodiments, each caster assembly 60 includes a plurality of teeth 76 defined along the inner surface of the wheel 58. An eccentric member 78 is coupled to one of the first links 72 to rotate with the first link 72 about its axis A. The eccentric member 78 (also referred to as a cam) includes an actuation protrusion 80 acting on a conversion head 82. The conversion head 82 is coupled to a conversion pin 84 that is movable in a vertical direction. A compression spring 86 is attached to the conversion pin 84 to bias the conversion pin 84 toward the eccentric member 78 in a vertically upward direction. The brake member 62 is coupled to the conversion pin 84 and includes a plurality of brake teeth 88 that are arranged to engage the teeth 76 defined along the inner surface of the wheel 58. During operation, when the first link 72 is rotated about its axis A via actuation of the manual actuator 68 or the electric brake assembly 70, the eccentric member 78 is rotated to move the actuation protrusion 80 along the contoured surface of the conversion head 82 to in a braking state ( Figure 5A ) and the release state ( Figure 5B ) between the brake member 62, in the braking state, the brake teeth 88 engage the teeth 76 defined along the inner surface of the wheel 58, and in the released state, the brake teeth 88 are spaced a certain distance from the teeth 76 defined along the inner surface of the wheel 58.

[0053] In the illustrated version of the patient transport apparatus 30, each of the pair of first links 72 extends between two caster assemblies 60 to operate the brakes 62 for both caster assemblies 60. In other words, rotation of one of the first links 72 operates the two brakes for both caster assemblies 60, and rotation of the other of the first links 72 operates the two brakes for the two other caster assemblies 60, such that all four caster assemblies 60 are braked substantially simultaneously (substantially simultaneously due to any tilt or tolerance in the linkage 66).

[0054] Other suitable caster assemblies having brakes operated via a hexagonal shaft or other suitable actuating member may also be used. For example, the caster assembly and associated brakes may be similar to those disclosed in U.S. Patent No. 8,789,662, entitled "Wheeled Carriage With Brake Lock System," which is incorporated herein by reference. In addition, the brake may also be an external brake or other form of brake operated via a linkage mechanism, but may not be part of the caster assembly.

[0055] refer to Figures 6A-6C , manual actuators 68 (one at the head end and one at the foot end) are connected to the linkage 66 to manually move the linkage 66, thereby placing the brake 62 in a braking state or a released state, or placing the steering lock mechanism in a steering lock state. The manual actuator 68 can be operated by a caregiver to place the linkage 66 and the brake 62 in a released state, thereby releasing the wheel 58 ( Fig. 6A ), or the nursing staff can operate to place the link mechanism 66 and the brake member 62 in the released state, thereby braking the wheel 58 ( Figure 6B ), or can be operated by a caregiver to place the linkage mechanism in a steering lock state ( Figure 6C ). Figures 6A-6C The manual actuator 68 shown in FIG. 1 moves the second connecting rod 74 along the first direction D1 to place the brake member 62 in the braking state (see FIG. 1 ). FIG. 6A to FIG. 6B and moves the second link 74 in the second direction D2 (see FIG. 6B to FIG. 6A Note that for the purpose of illustrating the movement of the linkage mechanism 66 between various states, the various components of the electromechanical brake system 64 are shown in FIG. Figures 6A-6C have been removed.

[0056] The electric brake assembly 70 is also connected to the linkage 66 and includes a motor 120 and a drive shaft 122, which is configured to move the linkage 66 to place the electromechanical brake system 64 in a braking state, a release state and / or a steering lock state. The electric brake assembly 70 has a drive member 106 further described below, which is configured to be moved by the drive shaft 122 to cause the second link 74 to move in the first direction D1, thereby placing the brake member 62 in a braking state, and cause the second link 74 to move in the second direction D2, thereby placing the brake member 62 in a released state from the braking state. The operating details of the manual actuator 68, the electric brake assembly 70, and the corresponding movements are described in U.S. Patent Application Publication No. 2019 / 0192364 entitled "Patient Transport Apparatus With Electro-Mechanical Braking System", which is incorporated herein by reference.

[0057] refer to Figure 7-10 In the illustrated embodiment, the linkage mechanism 66 includes a plurality of coupling links 90 (two at each head end and foot end, although only one end is shown). In the illustrated version, there are four coupling links 90 (two at each end). Each coupling link 90 couples one of the first links 72 to one of the second links 74. The linkage mechanism 66 also includes a pair of manually driven links 92 (one at each of the head end and foot end). Each manually driven link 92 is configured to be directly driven by one of the manual actuators 68 (one at each of the head end and foot end) to cause movement of the linkage mechanism 66. The linkage mechanism 66 also includes an electric link 94. The electric link 94 is configured to be driven by the drive member 106 of the electric brake assembly 70 to cause movement of the linkage mechanism 66. In the illustrated version, there is only one electric link 94, but other electric links 94 may be used.

[0058] like Figure 7 As best shown in FIG. 1 , each second link 74 defines a plurality of engagement slots 96 ( Figure 7Only one of the second links 74 is shown in the figure). Each engagement slot 96 is sized and shaped to receive a corresponding coupling link 90 or drive link 92, 94 therein. In the illustrated embodiment, each coupling link 90 and each drive link 92, 94 includes a sector gear 98. The sector gear 98 can be a separate component or an integral component of the coupling link 90 and the drive link 92, 94. The engagement slot 96 may include a plurality of engagement teeth 97 that are configured to contact corresponding teeth of the sector gear 98 during rotation of the sector gear 98 in its engagement slot 96. The sector gear 98 is positioned within the engagement slot 96 so that movement of the sector gear 98 is associated with movement of the second link 74. More specifically, the axis of rotation of the sector gear 98 is fixed relative to the base 34 so that rotation of the sector gear 98 causes the second link 74 (i.e., in the manner of a gear and rack) to slip between multiple states.

[0059] In some embodiments, the sector gear 98 rotates less than 90 degrees when moving between the various states, and in some cases, less than 60 degrees or less than 45 degrees, so that the total rotation of the sector gear 98 in the engagement slot 96 is less than 180 degrees, less than 120 degrees, or less than 90 degrees. In addition, the teeth of the two outer sector gears 98 (i.e., the coupling link 90) face generally downward during operation between the various states, while the teeth of the two inner sector gears (i.e., the drive links 92, 94) face generally upward during operation between the various states to at least partially limit the vertical movement of the second link 74.

[0060] like Figure 7 As shown, each coupling link 90 and each drive link 92, 94 is formed of two identical halves (including two halves of a sector gear 98) that are clamped together by an engaging slot 96 (only one half is numbered). The two halves may have suitable alignment features described further below to mate the two halves together. The halves may be secured to each other by any suitable method (e.g., welding, adhesives, fasteners, brazing, snap-fit ​​connections, etc.).

[0061] The sector gear 98 of the coupling link 90 is mounted to the first link 72, for example, by fitting the hexagonal through hole 99 of the sector gear 98 onto the hexagonal shaft. The sector gear 98 of the coupling link 90 may be mounted to the first link 72 in other ways so that these sector gears 98 rotate with the first link 72 during operation of the linkage 66. The sector gear 98 of the manual drive link 92 is mounted to the manual actuation shaft 100 of the manual actuator 68. The manual actuation shaft 100 is rotatably supported by the base 34. The sector gear 98 is mounted to the manual actuation shaft 100, for example, via a matching double D-type connection, so as to rotate with the manual actuation shaft 100 about its axis A2 when the manual actuator 68 is actuated by a caregiver (or when the manual actuation shaft 100 is passively rotated by the electric brake assembly 70, for example, during actuation). As further described below, the sector gears 98 of the electric linkage 94 rotate about the axis A3 of the drive shaft 122 in response to operation of the electric brake assembly 70. During operation of the linkage mechanism 66, the sector gears 98 rotate about their respective axes A, A2, A3, the second link 74 slides, and the first link 72 rotates about their axis A to move the plurality of brake members 62 between the plurality of states (see again). Figure 5A and Figure 5B ).

[0062] A brief review Fig. 6A and Figure 6B During operation of the electromechanical brake system 64, as the second link 74 slides in the first direction D1 (e.g., via actuation by the manual actuator 68 and the manual drive link 92, or via actuation by the electric brake assembly 70 and the electric link 94), the second link 74 causes movement of the coupling link 90 (via engagement of the sector gear 98 and the teeth 97), which causes the first link 72 to rotate in a counterclockwise direction about their axis A to move the brake member 62 to the braking state ( Figure 6B As the second link 74 slides in the second direction D2, the second link 74 moves the connecting link 90 to rotate the first link 72 in the clockwise direction around its axis A, thereby moving the corresponding brake member 62 to the released state ( Fig. 6A In some embodiments, further movement of the first link 72 in the clockwise direction moves the steering lock mechanism to the steering lock state.

[0063] Of course, although only the movement of one of the second links 74 is described above, when the first link 72 and the second link 74 are interconnected to operate substantially simultaneously, such movement also causes the movement of the other second link 74. More specifically, the other second link 74 also slides due to the coupling links 90 present at the opposite end of the patient transport device 30. These coupling links 90 couple the first link 72 to the other second link 74 (see Figure 3). The first connecting rod 72 and the second connecting rod 74 are used as described above. Figure 7-10 In some versions, there may be only one second link 74 and only one manual actuator 68, for example, another manual actuator 68 and another second link 74 may not be present.

[0064] refer to Figure 7 and Figure 8 , the manual drive link 92 is coupled to the manual actuator 68 so that the second link 74 can be manually moved in the first direction D1 and the second direction D2. In the illustrated embodiment, the manual actuator 68 includes a manual actuation shaft 100 and a brake pedal 102 coupled to the manual actuation shaft 100. The manual actuation shaft 100 is coupled to the brake pedal 102 so that the rotation of the brake pedal 102 causes the rotation of the manual actuation shaft 100 and the corresponding rotation of the manual drive link 92, which causes the second link 74 to slide in the first direction D1 or the second direction D2. For example, the sector gear 98 of the manual drive link 92 is configured to contact the meshing teeth 97 of the corresponding meshing slot 96 so that the rotation of the manual drive link 92 causes the second link 74 to slide. During operation, the caregiver can operate the brake pedal 102 to rotate the manual drive shaft 100 and the manual drive link 92 in a clockwise direction, thereby moving the second link 74 in the first direction D1 to move the brake member 62 to a braking state. The caregiver can operate the brake pedal 102 to rotate the manual actuation shaft 100 and the manual drive link 92 in a counterclockwise direction, thereby moving the second link 74 in the second direction D2 to move the brake member 62 to the released state. In some embodiments, further movement in the second direction D2 causes the steering lock mechanism to move to the steering lock state.

[0065] Special reference Figure 8 In the version shown, the manual actuation shaft 100 is supported by suitable bushings B or bearings to be pivoted in the base 34 about the axis A2 (e.g., in the embodiment shown in FIG. Figure 8The manual actuation shaft 100 is provided with a double-D-shaped portion 101 which is adapted to rotate in a housing or bracket of the base 34 shown. The double-D-shaped portion 101 of the manual actuation shaft 100 passes through the manual drive link 92 and appropriately cooperates with the manual drive link 92 (e.g., via a mating double-D-shaped opening in the manual drive link 92) for similar rotation. The double-D-shaped portion 101 has a double-D-shaped cross-sectional shape or other suitable rotation-limiting shape that matches a similarly shaped through hole in the manual drive link 92. The brake pedal 102 also defines a double-D-shaped hole 103 (or other suitable shape) to receive the double-D-shaped portion 101 of the manual actuation shaft 100, so that rotation of the brake pedal 102 results in rotation of the manual actuation shaft 100 and similar rotation of the manual drive link 92. The brake pedal 102 has a boss 105 that passes through an opening in a covering fixed to the base 34, which shields the manual drive link 92. A fastener 107 (e.g., a screw, bolt, etc.) may be inserted into another hole 109 of the brake pedal 102 that is transverse to the hole 103. The fastener 107 passes through a transverse through hole 111 in the double D-shaped portion 101 of the manual drive shaft 100 to axially secure the brake pedal 102 to the manual drive shaft 100. The other end of the manual drive shaft 100 is enlarged to axially retain the manual drive shaft 100 to the base 34 while allowing the manual drive shaft 100 to rotate relative to the base 34.

[0066] In some versions, the brake pedal 102 is formed by injection molding, and the hole 103 can be formed using a hydraulic slide so that the hole 103 has a draft angle of 0 degrees to allow a close fit with the double D-shaped portion 101 of the manual actuation shaft 100 and enable the load applied by the caregiver to travel through the brake pedal 102. The fastener 107 can be a removable fastener that is a plastic thread molding that is screwed into the plastic of the brake pedal 102 on both sides of the double D-shaped portion 101 to provide a secure hold of the brake pedal 102, thereby preventing the brake pedal 102 from sliding off the double D-shaped portion 101. In addition, if the double D-shaped portion 101 fails, the fastener 107 will serve as the main load-bearing component. #10 fasteners or other suitable fasteners can be used.

[0067] refer to Figure 7-11 The electric brake assembly 70 includes a drive member 106, a motor 120 (in Figure 41 and 12. The motor 120 and the drive shaft 122 form part of an actuator assembly 108. The actuator assembly 108 is coupled to the drive member 106 to provide torque to move the second connecting rod 74 in the first direction D1 and the second direction D2. The drive member 106 has a drive protrusion 110. The electric connecting rod 94 includes a positioning slot 114, the size and shape of which are designed to receive the drive protrusion 110 therein. The positioning slot 114 provides an arcuate travel path for the drive protrusion 110 and is sized so that the drive protrusion 110 can move along the travel path. The size and shape of the drive protrusion 110 are designed to contact the end of the travel path of the positioning slot 114. Once contact is made to either end of the travel path, further rotation of the drive protrusion 110 causes the electric connecting rod 94 to rotate about its axis A3 and corresponding movement of the second connecting rod 74. When the electric link 94 rotates about the axis A3 via the driving protrusion 110 , the sector gear 98 of the electric link 94 rotates in the engagement slot hole 96 thereof to drive the second link 74 as described above.

[0068] The drive member 106 is configured to move to a first position, a second position, and an original position (and in some cases, a third position if a steering lock is employed) via the motor 120 and the drive shaft 122. The electric brake assembly 70 drives the drive member 106 to the first position to move the second link 74 in the first direction D1, thereby placing the brake member 62 in a braking state, and to the second position to move the second link 74 in the second direction D2, thereby placing the brake member 62 in a released state from the braking state. The electric brake assembly 70 operates to move the drive member 106 to the original position (between the first position and the second position) to allow the second link 74 to move freely (without driving the motor 120 in reverse) and to enable the brake member 62 to be manually actuated using any one of the manual actuators 68. Movement between the first position, the second position, and the original position is described in detail in U.S. Patent Application Publication No. 2019 / 0192364, entitled “Patient Transport Apparatus With Electro-Mechanical Braking System,” which is incorporated herein by reference.

[0069] like Figure 9A-11As best shown in FIG. 1 , the power link 94 can be formed of identical halves H1, H2 that are sandwiched together by corresponding engagement slots 96 in the second link 74. The two halves H1, H2 of the power link 94 can have suitable alignment features to align the two halves for mating (e.g., see studs 126 and recesses 128). Similarly, the drive member 106 can be formed of identical halves H3, H4 that are sandwiched together by corresponding engagement slots 96. In this case, the drive protrusion 110 has two halves that meet in the two halves of the locating slot 114. Each of the two halves H3, H4 of the drive member 106 also has a cylindrical boss 130 that is sized and shaped to pass through a corresponding opening 132 in the two halves H1, H2 of the drive link 94.

[0070] like Fig.11 As shown, a first rivet 134 or other suitable fastener secures the two halves H1, H2 of the drive link 94 together. A second rivet 136 or other suitable fastener secures the two halves H3, H4 of the drive member 106 together and captures the two halves H1, H2 between the two halves H3, H4. The second rivet 136 also passes through the slots 114 in the two halves H1, H2. This facilitates the rotation of the drive member 106 relative to the drive link 94 during operation. Providing two separate rivets 134, 136 through the sector gear 98 of the drive link 94 helps prevent the two halves of the sector gear 98 from separating.

[0071] The actuator assembly 108 may include a linear actuator, a rotary actuator, or other types of actuators. The actuator assembly 108 is electric, electrohydraulic, hydraulic, pneumatic, etc. In the illustrated embodiment, the actuator assembly 108 includes a motor 120 (e.g., an electric motor) and a drive shaft 122, which is rotatably coupled to the motor 120 directly or through a gear train. The drive member 106 is coupled to the drive shaft 122 so that the rotation of the drive shaft 122 causes the drive protrusion 110 to rotate, for example, the drive protrusion 110 is mounted to the drive shaft 122 to rotate with the drive shaft 122. The motor 120 rotates the drive protrusion 110 through a variety of positions as defined and described in U.S. Patent Application Publication No. 2019 / 0192364 entitled "Patient Transport Apparatus With Electro-Mechanical Braking System", which is incorporated herein by reference. The linkage 66 is coupled to the brake member 62 such that rotation of the electric linkage 94 causes the linkage 66 to operate the brake member 62 to place the brake member 62 in a braking state or a released state, or to place the steering lock mechanism in a steering lock state.

[0072] Still reference Fig.11 In the illustrated embodiment, the electric brake assembly 70 includes a sensor assembly 125 that is configured to sense the position of the drive member 106. In one version, the sensor assembly 125 includes a pair of magnets M1, M2 that are fixed to a drive shaft 122 (the drive shaft 122 is driven directly by the motor 120 or through a gear train). The sensor assembly 125 also includes a sensor S1, such as a Hall effect sensor. The magnets M1, M2 are typically positioned to be offset 90 degrees (rotation angle) around the drive shaft 122. The magnets M1, M2 are fixed to the drive shaft 122 so that rotation of the drive shaft 122 causes the magnets M1, M2 to rotate relative to the sensor S1. The sensor S1 is fixed relative to the base 34 (e.g., in a sensor housing fixed to the base 34) so ​​as to sense the movement of the magnets M1, M2 in a non-contact manner. The sensor S1 and a single magnet M3 may also be as shown. Fig.11A Arrangement shown. Other arrangements are also contemplated. The controller 202 is coupled to the sensor S1 to determine the position of the drive shaft 122 by the controller 202 receiving a varying voltage signal from the sensor S1. For example, the sensor S1 is configured to generate a specific voltage or voltage range when the drive member 106 is in the home position, and the controller 202 can thereby store the range for later use in driving the drive shaft 122 to the home position. The controller 202 can therefore monitor the output from the sensor S1 to determine the position of the drive member 106.

[0073] The controller 202 is coupled to the motor 120 to control the operation of the motor 120 based on the input from the sensor S1, so that the motor 120 can rotate the drive shaft 122 and move the drive member 106 as needed to place the brake 62 in a braking state, a released state, or to place the steering lock mechanism in a steering lock state. Other sensor types are also contemplated, such as optical encoders, rotary Hall effect sensors, linear Hall effect sensors, proximity sensors, toggle switches, limit switches, etc. For example, an absolute position encoder can be used to sense the rotational position of the drive shaft 122.

[0074] refer to Fig. 12A , Fig. 12B and Fig.13 , the retainer 140 is coupled to the support structure 32. The retainer 140 cooperates with the linkage 66 to limit and / or guide the movement of the linkage 66. For example, the retainer 140 limits the longitudinal movement of the first link 72 and guides the sliding of the second link 74. In the illustrated embodiment, there are four retainers 140, but there may be more or fewer retainers in other embodiments. Only one of the retainers 140 will be described in detail.

[0075] like Fig. 12Aand Fig. 12B As best shown, each retainer 140 includes a locating post 142. The base 34 includes an opening 144 to receive the locating post 142 to orient the retainer 140 on the base 34 relative to the linkage 66. A fastener 146 secures each retainer 140 to the base 34 at a location spaced from the locating post 142. The retainers 140 also include a wire manager or shield 148 under which electrical cables or other forms of conduits, cables, wires, etc. can be placed for routing / managing these wires.

[0076] like Fig.13 As best shown in , each retainer 140 includes a stopper 150 to engage one end of the first link 72, thereby limiting the movement of the first link 72. Each retainer 140 also includes a guide 152 to receive the second link 74, thereby limiting and guiding the movement of the second link 74. The stopper 150 includes a wall 154, which is arranged to limit the longitudinal movement of the first link 72 by providing an abutment for the first link 72. The guide 152 defines a recess 156 to receive the second link 74 and allow the second link 74 to slide relative to the retainer 140 in the recess 156. The sector gear 98 of the coupling link 90 operatively couples the first link 72 to the second link 74, and the recess 156 is shaped and arranged to receive the coupling link 90 and allow the sector gear 98 to move within the recess 156 during operation of the linkage mechanism 66.

[0077] In the illustrated embodiment, each retainer 140 comprises an integral structure that is secured to the base 34. In some versions, the stopper 150 and the guide 152 are integrally formed as a piece of plastic material, and the retainer 140 may be formed by injection molding. The retainer 140 may be formed of other materials. The guide 152 is formed to have a top wall and side walls that form a notch 156 to span across the second link 74 while still allowing the sector gear 98 to rotate. The retainer 140 also includes a contoured recess 157 (see Fig. 12B ) to receive the first link 72. In some versions, the first link 72 can be on the caster housing CH (see Fig.13 ), whereby the stops 150 at each end limit such sliding and prevent the first link 72 from falling out of the sector gear 98 of the coupling link 90. ​​Each retainer 140 is configured to be fully compressed with the base 34 in the event of a collision. The base 34 may include a bumper 160 at each of the head end and the foot end. The bumper 160 is positioned to protect the retainer 140 from impact. The bumper 160 may be formed of sheet metal or other suitable material.

[0078] like Fig.14 and Fig.15As shown, each of the casters 60 includes a caster stem 162 that is coupled to one of the plurality of wheels 58 (or the plurality of wheels for a dual wheel caster). The caster stem 162 includes a non-circular interface 164, and the bumper 160 includes mating openings 166 that are shaped to receive the non-circular interface 164 of the caster stem 162 and limit rotation of the caster stem 162 relative to the bumper 160. The bumper 160 can be reinforced (e.g., thickened, ribbed, etc.) at the opening 166 to further support the caster stem 162. In some versions, the non-circular interface 164 includes an octagonal feature at the bottom of the caster stem 162 that fits into a corresponding octagonal opening in the bumper 160 to prevent the caster stem 162 from rotating relative to the base 34. Other rotation limiting shapes are also possible.

[0079] refer to Fig.16 and Fig.17 , link supports 170 are mounted to the base 34 to rotatably support the first links 72 (one for each first link 72). This helps prevent the first links 72 from sagging and rattling against the base 34 because the first links 72 span longitudinally from one end of the patient transport device 30 to the other end. Each link support 170 can be formed from a single piece of plastic and shaped to capture the first link 72 and space the first link 72 from the base 34. The link supports 170 can have a receiving portion 172 and an attachment portion 174. The receiving portion 172 is C-shaped and substantially surrounds the outer periphery of the first link 72. The receiving portion 172 can also have a capture tab 173 that flexes when the receiving portion 172 is assembled to the first link 72 and prevents the first link 72 from easily popping out of the receiving portion 172. The attachment portion 174 may have fasteners (eg, Christmas tree connectors, screws, pins, clips, or other suitable fasteners) to attach to the base 34 via one or more openings in the base frame 35 .

[0080] refer to Fig.18 In the illustrated embodiment, the patient transport device 30 includes a control system 200 to control the operation of the electromechanical brake system 64. The control system 200 includes a controller 202 having one or more microprocessors, microcontrollers, field programmable gate arrays, systems on a chip, discrete circuits, and / or other applicable hardware, software, or firmware capable of performing the functions described herein. The controller 202 may be onboard the patient transport device 30 or may be remotely located. In one embodiment, the controller 202 is mounted to the base 34. In other embodiments, the controller 202 is mounted to the riser 54. Power to the electric brake assembly 70 and / or the controller 202 may be provided by a battery power source and / or an external power source. The controller 202 is configured to allow the controller 202 to control the actuator assembly 108 ( Fig.181 and 2. The controller 202 may be coupled to the electric brake assembly 70 by way of a connection schematically shown in FIG. 1. The controller 202 may communicate with the actuator assembly 108 via a wired or wireless connection to perform one of a variety of intended functions.

[0081] The control system 200 also includes a position sensor 204 coupled to the controller 202 that responds to the operation of the linkage 66 to determine the current state of the linkage 66. The position sensor 204 may be mounted to the brake member 62 for sensing the position of the brake member 62. The position sensor 204 may also be coupled to the actuator assembly 108 and configured to measure the rotation of the motor 120. The position sensor 204 may also be mounted to the manual actuation shaft 100 and / or the brake pedal 102 to determine the position of the brake pedal 102 and associate these positions with a braking state, a release state, or a steering lock state. Fig.19 and Fig.21 In the version shown in FIG. 2 , the position sensor 204 includes a pair of limit switches 206 a , 206 b mounted to a circuit board 208 that is secured to the base 34 .

[0082] Rough reference Figure 19-24 , the sensor actuator 210 is connected to the linkage 66 to move between a braking state, a release state and / or a steering lock state together with the linkage 66. The sensor actuator 210 has an actuation head 212 and an engagement interface 214, wherein the actuation head 212 is supported by the support structure 32 to slide relative to the limit switches 206a, 206b, and the engagement interface 214 is carried by the linkage 66 to move together with the linkage 66. In the representative embodiment shown herein, the engagement interface 214 is implemented as a slidable element (or "slider"), as described in more detail below. However, it will be understood that other configurations are contemplated. The engagement interface 214 includes a button connector 216 that fits into a corresponding recess 217 in the second link 74 (see Fig.10 ), so that the sliding of the second link 74 causes the corresponding sliding of the engagement interface 214. The button connector 216 has a rod and a head, the rod is fitted into the recess 217 in the second link 74, and the head holds the rod in the recess 217.

[0083] like Fig.19 and Fig. 20As shown, the buffer 160, which forms part of the support structure 32, includes a buffer rail 218. The engagement interface 214 defines a first rail 220 to straddle and ride along the buffer rail 218. The electronics housing is fixed to the buffer 160 and includes a head rail 219 located at a distance from the buffer rail 218. The head rail 219 is fixed in an appropriate position relative to the buffer rail 218. The actuating head 212 defines a second rail 221 to straddle and ride along the head rail 219.

[0084] The sensor actuator 210 includes one or more flexible connectors 222 that interconnect the actuation head 212 and the engagement interface 214 so that the actuation head 212 is flexibly connected to the engagement interface 214 to adjust the distance between the actuation head 212 and the engagement interface 214. More specifically, the one or more flexible connectors 222 are flexible to adjust the distance between the bumper rail 218 and the head rail 219 to accommodate manufacturing tolerances in different patient transport devices 30. For example, large tolerances may be specified for the manufacture of the bumper 160, which will result in variations in the distance between the bumper rail 218 and the head rail 219 between different patient transport devices 10 manufactured by the same manufacturer. The one or more flexible connectors 22 are provided to accommodate such variations.

[0085] In some versions, sensor actuator 210 is formed from plastic (eg, by injection molding) and flexible connector 222 includes one or more plastic strips that allow sensor actuator 210 to flex. Figure 22-24 In the illustrated version, the flexible connector 222 includes flexible legs extending from the actuation head 212 to the engagement interface 214. Alternatively, the actuation head 212 may be coupled to the engagement interface 214 via other resilient members (e.g., springs, rubber connectors, etc., or any other suitable flexible features).

[0086] like Fig.19 and Fig.23 As best shown, the actuator head 212 includes a plurality of cams (e.g., a first cam 224a and a second cam 224b) to engage the first arm 226a of the limit switch 206a and the second arm 226b of the limit switch 206b. Fig.19 and Fig.21In the release state (neutral state) shown, the first cam 224a engages the first arm 226a to activate the associated limit switch 206a, while the second arm 226b remains out of contact with the second cam 224b. When moving from the release (or neutral) state to the braking state, the engagement interface 214 is moved due to the movement of the second link 74, and the first cam 224a slides to the right and disengages from the first arm 226a, while the second cam 224b slides to contact with the second arm 226b to activate the associated limit switch 206b. When moving from the release (or neutral) state to the steering lock state, the engagement interface 214 is moved due to the movement of the second link 74, and the first cam 224a slides to the left and disengages from the first arm 226a, while the second cam 224b continues to be out of contact with the second arm 226b. Therefore, the different activation states of the limit switches 206a, 206b enable the controller 202 to determine the current state of the linkage 66.

[0087] In some cases, during assembly, it may be difficult to precisely position the cams 224a, 224b so that the cams 224a, 224b engage the arms 226a, 226b just as the electromechanical brake system 64 changes state (e.g., when the brake 62 is fully engaged or fully released). As a result, if one of the arms 226a, 226b is contacted prematurely, i.e., before the state change actually occurs, the controller 202 may erroneously detect that a state change has occurred, or otherwise stop operation of the actuator assembly 108 before the state change is actually completed, thereby potentially leaving the electromechanical brake system 64 in an undesirable state. To avoid incomplete state changes, the controller 202 may be programmed to sample the signals from the limit switches 206a, 206b for a period of time that exceeds the period of time that the cams 224a, 224b contact the arms 226a, 226b to ensure a complete change of state, e.g., complete activation / deactivation of the brake 62. For example, with a sample size of 2 and a frequency of 5 ms, when the second cam 224 b initially slides into contact with the second arm 226 b to activate the associated limit switch 206 b, the controller 202 recognizes the activation and continues to sample the signal from the limit switch 206 b for 10 ms, such that the controller 202 continues to drive the motor 120 slightly beyond the activation point (by reading the activation signal for a longer period of time) to ensure that the electromechanical braking system 64 is in the desired state, at which point the motor drive 120 is stopped.

[0088] Return to reference Fig.18, the control system 200 also includes a status indicator 230 coupled to the controller 202. The controller 202 is configured to operate the status indicator 230 to indicate a sensed state of the electromechanical brake system 64. The status indicator 230 may include one or more visual indicators, audible indicators, and / or tactile indicators to indicate the sensed state. The status indicator 230 may be coupled to the hand brake pedal 102, the base 34, the lateral rails 44, 46, 48, 50, the headboard 52 or the riser 54, or any portion of the patient transport device 30.

[0089] The control system 200 may include a user interface having one or more user input devices 232, which are operated by a caregiver and transmit corresponding input signals to the controller 202. The controller 202 controls the operation of the actuator assembly 108 based on the input signals. The user input device 232 may include any device that can be activated by a caregiver. The user input device 232 can be configured to be activated in a variety of different ways, including but not limited to mechanical activation (hand, foot, finger, etc.), hands-free activation (voice, foot, etc.), etc.

[0090] The user input device 232 may also include a gesture sensing device for monitoring the movement of the hands, feet, or other body parts of the caregiver (e.g., via a camera), a microphone for receiving voice-activated commands, a foot pedal, and sensors (e.g., infrared sensors such as light bars or beams for sensing body parts of the caregiver, ultrasonic sensors, etc.). In addition, the user input device 232 may include buttons / pedals, which may be physical buttons / pedals or buttons / pedals that are virtually implemented, for example, via optical projection or on a touch screen. The buttons / pedals may also be mechanically connected or wire-controlled buttons / pedals, where the force applied by the caregiver actuates a sensor, such as a switch or potentiometer. It should be understood that any combination of user input devices 232 may also be used. The user input device 232 may be positioned on one of the lateral rails 44, 46, 48, 50, the headboard 52, the riser 54, or other applicable locations. The user input device 232 may also be positioned on a portable electronic device (e.g., or similar electronic device).

[0091] In the illustrated embodiment, the controller 202 includes a processor 234 and a storage device 236. The processor 234 includes any applicable programmable circuit, which may include one or more system and microcontrollers, microprocessors, reduced instruction set circuits (RISC), application specific integrated circuits (ASICs), programmable logic circuits (PLCs), field programmable gate arrays (FPGAs), and any other circuits capable of performing the functions described herein. The above examples are exemplary only and are therefore not intended to limit the definition and / or meaning of the term "processor" in any way. The storage device 236 includes a computer-readable medium, such as, but not limited to, a random access memory (RAM), a flash memory, a hard drive, a solid-state drive, a floppy disk, a flash drive, a compact disk, a digital video disk, and / or any applicable device that enables the processor 234 to store, retrieve, and / or execute instructions and / or data.

[0092] In an exemplary embodiment, the controller 202 includes a motor control module 238 that is coupled to the actuator assembly 108 to control the operation of the actuator assembly 108. The motor control module 238 is configured to execute programming code in response to input received by a caregiver via a user interface to operate the actuator assembly 108 based on the user input. In addition, the controller 202 also includes a sensor module 240 that is coupled to at least one sensor, such as the sensor S1 and the position sensor 204. The sensor module 240 is configured to receive data from the sensor and send the received data to the motor control module 238 to facilitate operating the electric brake assembly 70. Each sensor can transmit a signal continuously, periodically, or only once and / or with any other signal timing that enables the controller 202 to function as described herein. In addition, each sensor can transmit a signal in analog form or in digital form.

[0093] The controller 202 also includes a user input module 242 that is configured to receive input signals from the user input device 232 and / or generate and display images for display on one or more display devices of the user interface. For example, the user input module 242 can retrieve image data stored in the storage device 236 and transmit the image data to the user interface so that one or more display devices can display the image to the caregiver. The user input module 242 also sends a signal to the status indicator 230 to operate the status indicator 230 to indicate the sensed state.

[0094] During operation of the electric brake assembly 70, when the caregiver wishes to engage or release the brake 62, the caregiver activates one or more user input devices 232. For example, if the caregiver wishes to brake the wheels 58 to stop the movement of the patient transport device 30, the caregiver activates the appropriate user input device 232. Once activated, the controller 202 sends an output signal to the actuator assembly 108 to cause corresponding movement operation of the actuator assembly 108. Similarly, one or more user input devices 232 can be used to release the brake 62, or place the electromechanical brake system 64 in the steering lock state.

[0095] refer to Fig.25 In some embodiments, the actuator assembly 108 is driven to its maximum limit by intentionally reaching a hard stop of one or more of the sector gears 98. The hard stop can be provided by the sector gear 98 being in hard contact with the side portions 246, 248 of one or more of the meshing slots 96, i.e., in hard contact with the wall of the second link 74 (which, like the sector gear 98, can be formed of metal). For example, the motor 120 drives the linkage 66 until one of the sector gears 98 abuts against one of the sides 246, 248 of its corresponding meshing slot 96, as shown in FIG. Fig.25 26 , i.e., there is no further travel available for the sector gear 98 in the engagement slot 96. This allows for maximum movement of the linkage 66 without any hard stops within the caster assembly 60 (which would otherwise damage the caster assembly 60). However, when operating at high speeds and torques, always hard stopping the sector gear 98 against the sides 246, 248 of the engagement slot 96 may result in damage to the sector gear 98, the drive member 106, or other components. Therefore, it may be desirable to reduce the operating speed and / or torque of the motor 120, but this may sacrifice, for example, the time to engage or disengage the brake member 62. Therefore, referring to FIG. 26 , in one embodiment, the controller 202 may initially drive the motor 120 at a first duty cycle 250 (e.g., at a duty cycle of 95%), thereby moving the linkage 66 toward one of the desired states using pulse width modulation. However, when the electromechanical brake system 64 detects that the linkage 66 is approaching a braking state (or begins to enter the braking state), for example, the controller 202 immediately begins to reduce the duty cycle to a second duty cycle 252 , such as a 25% duty cycle.

[0096] Approaching (or entering) a braking state may be sensed using a position sensor 204 or other applicable sensor (e.g., a SPDT switch), which may provide input to the controller 202 to control the motor 120 accordingly. For example, the initial activation of the limit switch 206b may indicate approaching (or entering) a braking state and trigger such a change in motor control. Once movement toward the braking state is initially sensed, the linkage 66 may move further to ensure full engagement of the brake 62. For example, the controller 202 may cause the motor 120 to drive for an additional period of time until the hard stop position of the sector gear 98 is reached, the additional period of time being, for example, one second or other applicable time. The hard stop may be sensed by monitoring the motor current and detecting a current peak associated with such a hard stop. However, by reducing the duty cycle before reaching the hard stop, the associated current and corresponding torque when the hard stop is finally reached may be reduced. In some cases, a reduction from the first duty cycle 250 to the second duty cycle 252 may result in a reduction in the current associated with the hard stop from about 6A to 1.5A, and an effective reduction in the output torque associated with the hard stop of more than 50%.

[0097] Several configurations have been discussed in the foregoing description. However, the configurations discussed herein are not intended to be exhaustive or to limit the invention to any particular form. The terms used are intended to have the nature of description rather than restrictive words. In view of the above teachings, many modifications and variations are possible, and the invention may be implemented in a manner different from that specifically described.

Claims

1. A patient transport device, comprising: a support structure comprising a base and a patient support platform; a plurality of wheels coupled to the support structure; a plurality of brake members arranged to brake the wheels; a linkage mechanism operatively coupled to the plurality of brake members and operable between a braking state for braking the plurality of wheels and a releasing state for releasing the plurality of wheels, the linkage mechanism comprising: a first link rotatably supported by the base and coupled to the plurality of brake members to move the plurality of brake members between the braking state and the releasing state, a second link operatively coupled to the first link by a gear and supported by the base to slide laterally relative to the base to move the plurality of brakes between the braking state and the released state; and a retainer coupled to the support structure and cooperating with the linkage to limit movement of the linkage, the retainer comprising: a stopper comprising a wall arranged to limit longitudinal movement of the first link; and A guide defines a recess shaped and arranged to receive the second link and allow sliding movement of the second link in the recess relative to the retainer during operation of the linkage.

2. The patient transport device according to claim 1, wherein: The holder includes a unitary structure secured to the base.

3. The patient transport device of claim 1, wherein: The stopper and the guide are integrally formed as one piece of plastic material.

4. The patient transport device of claim 1, wherein: The first link comprises an elongated shaft having a hexagonal cross-sectional shape, and the wall is arranged to limit longitudinal movement of the elongated shaft.

5. The patient transport device of claim 1, wherein: The second link includes a rack, and the recess is shaped and arranged to receive the rack and allow sliding movement of the rack in the recess relative to the retainer.

6. The patient transport device of claim 5, wherein: The recess is shaped and arranged to receive the gear and allow the gear to move within the recess during operation of the linkage.

7. The patient transport device of claim 1, wherein: The retainer includes a locating post, and the base includes an opening to receive the locating post to orient the retainer on the base relative to the linkage.

8. The patient transport device of claim 1, wherein: The holder includes a line manager.

9. The patient transport device of claim 1, wherein: The base includes a bumper positioned to protect the retainer from impact.

10. The patient transport device of claim 9, wherein: The patient transport apparatus includes a caster stem coupled to one of the plurality of wheels, the caster stem including a non-circular interface and the bumper including an opening shaped to receive the non-circular interface and limit rotation of the caster stem relative to the bumper.

11. The patient transport device of claim 1, wherein: The patient transport apparatus includes a link support mounted to the base to rotatably support the first link, the link support being formed of plastic and shaped to capture the first link and space the first link apart from the base.

12. A patient transport device comprising: a support structure comprising a base and a patient support platform; a plurality of wheels coupled to the support structure; a plurality of brake members configured to brake the wheels; a linkage mechanism operatively coupled to the plurality of brake members and operable between a braking state for braking the plurality of wheels and a releasing state for releasing the plurality of wheels; a position sensor responsive to operation of the linkage mechanism to determine whether the linkage mechanism is in the braking state or the released state; and a sensor actuator coupled to the linkage mechanism to move with the linkage mechanism between the braking state and the releasing state, the sensor actuator having an actuating head and an engagement interface, the actuating head being supported by the support structure to move relative to the position sensor, the engagement interface being carried by the linkage mechanism to move with the linkage mechanism, Wherein, the sensor actuator includes one or more flexible connectors, which interconnect the actuator head with the bonding interface, so that the actuator head is flexibly connected to the bonding interface to adjust the distance between the actuator head and the bonding interface.

13. The patient transport device of claim 12, wherein: The support structure includes a guide rail; and The engagement interface defines a track that rides along the rail, wherein the one or more flexible connectors are flexible to adjust a distance between the rail and the position sensor.

14. The patient transport device of claim 12, wherein: The position sensor includes a plurality of switches, and the actuation head includes a plurality of cams to engage the plurality of switches.

15. The patient transport device of claim 12, wherein: The patient transport apparatus includes a manual actuator operatively coupled to the linkage mechanism to move the linkage mechanism between the braking state and the released state.

16. The patient transport device of claim 15, wherein: The patient transport device includes an electric brake assembly, the electric brake assembly comprising: a drive member coupled to the linkage; and a motor coupled to the drive member and configured to move the drive member to a first position, a second position, and a home position between the first position and the second position, wherein movement of the drive member to the first position causes the linkage mechanism to place the brake member in the braking state, movement of the drive member to the second position causes the linkage mechanism to place the brake member in the released state, and Wherein, movement of the drive member to the original position allows the linkage mechanism to move relative to the drive member so that the brake can be manually actuated using the manual actuator.

17. The patient transport device of claim 16, wherein: The electric brake assembly also includes: a drive shaft rotatably coupled to the drive member and disposed in rotational communication with the motor; and A sensor assembly is configured to sense movement of the drive member between the first position and the second position.

18. The patient transport device of claim 17, wherein: The sensor assembly comprises: a pair of magnets fixed to the drive shaft; and A sensor is fixed relative to the base and configured to sense movement of the pair of magnets.

19. The patient transport device of claim 18, wherein: The sensor includes a Hall effect sensor configured to sense movement of the pair of magnets without contacting the pair of magnets.

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