Lift system and load cell for a patient support device

Abstract

The patient support apparatus includes a base and a support frame. A lift system operates to raise and lower the support frame relative to the base. The lift system includes a first lift and a second lift. The first lift and the second lift are independently operable to set the support frame in one or more Trendelenburg positions. A plurality of load cells act between the lifts and the support frame, whereby loads on the support frame are transferred to the plurality of load cells for measurement. The first lift includes a guided body arranged to move longitudinally relative to the base in response to operation of the second lift to move the support frame into one or more Trendelenburg positions.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority to and the entire benefit of U.S. Provisional Patent Application No. 63 / 030478, filed May 27, 2020, the entire contents and disclosure of which are incorporated by reference in their entirety. [Background technology]

[0002] Patient support apparatus, such as hospital beds, facilitate patient care in healthcare settings. A conventional patient support apparatus includes a base, a support frame on which a patient is supported, a lift system for raising and lowering the support frame relative to the base, and a number of load cells for measuring the patient's weight or detecting the patient's position or movement. Sometimes, it is desirable for the lift system to be able to place the patient in one or more Trendelenburg positions. However, depending on the placement of the load cells, measurements taken in one or more Trendelenburg positions may be less accurate than desired. Summary of the Invention

[0003] The present disclosure provides a patient support apparatus including a support structure having a base, a support frame, and a patient support deck, wherein the support frame extends longitudinally from a first longitudinal end to a second longitudinal end, and the base has a guide. A first lift is provided for raising or lowering the first longitudinal end of the support frame relative to the base. The first lift has a guided body that is vertically movable relative to the base along the guide. A second lift is provided for raising or lowering the second longitudinal end of the support frame relative to the base. The first lift and the second lift are operable to set the support frame in one or more Trendelenburg positions in which the first longitudinal end and the second longitudinal end are at different heights relative to the base. The patient support apparatus further includes a plurality of load cells, at least one load cell coupled to the first lift for acting between the first lift and the support frame, and at least one load cell coupled to the second lift for acting between the second lift and the support frame, such that a load applied to the support frame is transmitted to the plurality of load cells to measure the load. The guided body is arranged to move longitudinally relative to the base in response to operation of the second lift to move the support frame into one or more Trendelenburg positions, whereby the first lift moves longitudinally toward the second lift to accommodate movement of the support frame into one or more Trendelenburg positions.

[0004] The present disclosure also provides a load cell including an elongated body extending longitudinally along a longitudinal axis from a mounting portion to a load application portion. The load application portion defines a pair of side openings and a pivot shaft passage extending between the side openings, with the load application region located midway through the pivot shaft passage. Each of the pair of side openings has a first diameter, and the pivot shaft passage has a second diameter at the load application region, the second diameter being smaller than the first diameter. [Brief explanation of the drawings]

[0005] [Figure 1] 1 is a perspective view of a patient support apparatus. [Figure 2]2 is a schematic elevational view of the patient support apparatus of FIG. 1 with the support frame at a first height relative to the base. [Figure 3] 2 is a schematic elevational view of the patient support apparatus of FIG. 1 with the support frame lowered to a second height relative to the base. [Figure 4A] 2 is a schematic elevational view of the patient support apparatus of FIG. 1 with the support frame in the Trendelenburg position. [Figure 4B] 2 is a schematic elevational view of the patient support apparatus of FIG. 1 with the support frame in another Trendelenburg position. [Figure 5] 2 is a top schematic view of the patient support apparatus of FIG. 1 showing portions of the support frame, lift system, load cell, and base. [Figure 5A] 2 is a close-up view of the lift of the patient support apparatus of FIG. 1. [Figure 5B] 2 is a close-up view of the lift of the patient support apparatus of FIG. 1 having an alternative actuator. [Figure 5C] 5C is a schematic elevational view of the patient support apparatus of FIG. 1 having the alternative actuator of FIG. 5B. [Figure 6] 1 is a schematic elevational view of another patient support apparatus with a support frame at a first height relative to a base. [Figure 7A] 7 is a schematic elevational view of the patient support apparatus of FIG. 6 with the support frame in the Trendelenburg position. [Figure 7B] 7 is a schematic elevational view of the patient support apparatus of FIG. 6 with the support frame in another Trendelenburg position. [Figure 8] 7 is a top schematic view of the patient support apparatus of FIG. 6 showing portions of the support frame, lift system, load cell, and base. [Figure 9] 7 is a schematic elevational view of the patient support apparatus of FIG. 6 with the support frame at a first height relative to the base and the load cells in an alternative position. [Figure 10] 10 is a schematic elevational view of the patient support apparatus of FIG. 9 with the support frame in the Trendelenburg position. [Figure 11]10 is a top schematic view of the patient support apparatus of FIG. 9 showing portions of the support frame, lift system, load cell, and base. [Figure 12] 7 is a schematic elevational view of the patient support apparatus of FIG. 6 with the support frame at a first height relative to the base and the load cells in an alternative position. [Figure 13] 13 is a schematic elevational view of the patient support apparatus of FIG. 12 with the support frame in the Trendelenburg position. [Figure 14] 1 is a schematic elevational view of another patient support apparatus with a support frame at a first height relative to a base. [Figure 15] 15 is a schematic elevational view of the patient support apparatus of FIG. 14 with the support frame in the Trendelenburg position. [Figure 16] 1 is a schematic diagram of a control system. [Figure 17] FIG. 2 is a perspective view of the arrangement of load cells of the patient support apparatus of FIG. 1. [Figure 18] FIG. 2 is a top perspective view of a load cell. [Figure 19] FIG. 19 is a bottom perspective view of the load cell of FIG. 18. [Figure 20] FIG. 19 is a top view of the load cell of FIG. 18. [Figure 21] FIG. 19 is a side view of the load cell of FIG. 18. [Figure 22] FIG. 19 is a bottom view of the load cell of FIG. 18. [Figure 23] 23 is a cross-sectional view of the load cell of FIG. 18 taken generally along line 23-23 of FIG. 18. [Figure 24] FIG. 19 is a partial enlarged view of the bushing and block of the load cell of FIG. 18. [Figure 24A] FIG. 10 is a partial enlarged view of another bushing and another block of the load cell. [Figures 25A-25C] 10A-10C illustrate various positions of the pivot shaft within the bushing of the load cell. [Figure 26]25C is a cross-sectional view of the two load cells of FIG. 18 taken generally along line 26-26 of FIG. Note that the cross-section for one of the load cells is inverted from the orientation shown on line 26-26. [Figure 27] FIG. 10 is a cross-sectional view of another load cell. DETAILED DESCRIPTION OF THE INVENTION

[0006] Referring to Figure 1, there is shown a patient support apparatus 30 for supporting a patient in a healthcare setting. The patient support apparatus 30 shown in Figure 1 is a hospital bed. However, in other versions, the patient support apparatus 30 can be a stretcher, a cot, a table, a wheelchair, or similar equipment utilized in patient care.

[0007] The support structure 32 provides support for the patient. The support structure 32 shown in FIG. 1 includes a base 34 and a support frame 36. The base 34 includes a base frame 35. The support frame 36 is spaced above the base frame 35 in FIG. 1. The support structure 32 also includes a patient support deck 38 disposed on the support frame 36. The patient support deck 38 includes several sections, some of which are articulatable (e.g., pivotable) relative to the support frame 36, such as a Fowler section, a seat section, a thigh section, and a foot section. The patient support deck 38 provides a patient support surface 42 on which the patient is supported.

[0008] The mattress 40 is disposed on the patient support deck 38 during use. The mattress 40 comprises a secondary patient support surface on which a patient is supported. The base 34, the support frame 36, the patient support deck 38, and the patient support surface 42 each have a head end and a foot end corresponding to the intended positioning of the patient's head and foot on the patient support apparatus 30. The head end and the foot end may also be referred to as opposing longitudinal ends. The base 34 includes a longitudinal axis L1 extending along its length from the head end to the foot end. The base 34 may also include a vertical axis V disposed intersecting (e.g., perpendicular to) the longitudinal axis L1, along which the support frame 36 is raised and lowered relative to the base 34. The structure of the support structure 32 may be of any known or conventional design and is not limited to those specifically described above. Furthermore, the mattress 40 may be omitted in certain versions, thereby allowing the patient to rest directly on the patient support surface 42.

[0009] The side rails 44, 46, 48, and 50 are coupled to the support structure 32. The first side rail 44 is positioned at the right head end of the patient support deck 38. The second side rail 46 is positioned at the right foot end of the support frame 36. The third side rail 48 is positioned at the left head end of the patient support deck 38. The fourth side rail 50 is positioned at the left foot end of the support frame 36. If the patient support apparatus 30 is a stretcher or cot, fewer side rails may be present. The side rails 44, 46, 48, and 50 are movable between a raised position that blocks entry and exit from the patient support apparatus 30, one or more intermediate positions, and a lowered position that does not obstruct such entry and exit. In some configurations, the patient support apparatus 30 may not include side rails.

[0010] The headboard 52 and the footboard 54 are coupled to the support frame 36. In some versions, when the headboard 52 and the footboard 54 are included, the headboard 52 and the footboard 54 may be coupled elsewhere on the patient support apparatus 30, such as to the base 34. In some versions, the patient support apparatus 30 does not include at least one of the headboard 52 and the footboard 54.

[0011] Caregiver interfaces 56, such as handles, are shown integrated into the footboard 54 and siderails 44, 46, 48, 50 to facilitate movement of the patient support apparatus 30 across a floor surface. Additional caregiver interfaces 56 may be integrated into the headboard 52 and / or other components of the patient support apparatus 30. The caregiver interfaces 56 can be grasped by a caregiver to manipulate the patient support apparatus 30 for movement.

[0012] Wheels 58 are coupled to the base 34 to facilitate transportation over a floor surface. Wheels 58 are located adjacent the corners of the base 34 in each of the four quadrants of the base 34. In the version shown, the wheels 58 are caster wheels that can rotate and swivel relative to the support structure 32 during transportation. Each of the wheels 58 forms part of a caster assembly 60. Each caster assembly 60 is attached to the base 34. It should be understood that various configurations of the caster assembly 60 are contemplated. Furthermore, in some versions, the wheels 58 are not caster wheels and can be non-steerable or steerable, non-motorized or motorized, or any combination thereof. Additional wheels are also contemplated. For example, the patient support apparatus 30 can include four non-motorized, non-steerable wheels along with one or more motorized wheels. In some cases, the patient support apparatus 30 may not include wheels. In some versions, one or more auxiliary wheels (powered or non-powered) that are movable between a stowed position and a deployed position may be coupled to the support structure 32.

[0013] The patient support apparatus 30 includes a lift system 70 that operates to raise and lower the support frame 36 and the patient support deck 38 relative to the base 34. The lift system 70 is configured to move the support frame 36 from a first height (shown in FIG. 2 ) to a lower second height (shown in FIG. 3 ), or to any desired position therebetween. The lift system 70 includes a head-end lift 72 and a foot-end lift 74. The head-end lift 72 is positioned to raise or lower the head-end of the support frame 36 relative to the base 34. The foot-end lift 74 is positioned to raise or lower the foot-end of the support frame 36 relative to the base 34. The head-end lift 72 and the foot-end lift 74 each include an actuator 76, 77 that actuates the lift 72, 74. The lifts 72, 74 are operable separately and independently, allowing the support frame 36 and patient support deck 38 to be set in one or more Trendelenburg positions with the head and foot ends at different heights relative to the base 34, as shown in Figures 4A and 4B.

[0014] The lifts 72, 74 can have the same or different configurations. For example, one of the lifts can be a crank-type mechanism or a scissor-type mechanism, while the other of the lifts can be a column lift. The head-end lift 72 and the foot-end lift 74 can be interchangeable, such that the head-end lift 72 is at the foot end of the patient support apparatus 30 and the foot-end lift 74 is at the head end of the patient support apparatus 30. Figures 2-4B are elevational schematic diagrams illustrating the lifts 72, 74 and their operation. The mattress 40, side rails 44, 46, 48, 50, headboard 52, and footboard 54 are omitted from Figures 2-4B for illustrative purposes.

[0015] The head-end lift 72 includes one or more head-end legs 78, and the foot-end lift 74 includes one or more foot-end legs 80. In the version shown, there are two laterally spaced head-end legs 78 and two laterally spaced foot-end legs 80. Because FIGS. 2-4B are elevational schematics, only one head-end leg 78 and one foot-end leg 80 are shown for ease of illustration. The other head-end leg 78 and foot-end leg 80 and their connections are the same as those shown, but on the opposite side of the base frame 35 (i.e., only one interior side of the base frame 35 is shown in FIGS. 2-4B). The head-end legs 78 and foot-end legs 80 are similarly positioned, but in the opposite direction. All of the legs 78, 80 are visible in FIGS. 1 and 5.

[0016] 2-4B, each of legs 78, 80 extends at an acute angle (relative to longitudinal axis L1) from a first end pivotally coupled to load cell 82 to a second end pivotally and slidably coupled to base 34. More specifically, the first end is pivotally coupled to load cell 82 at an upper pivot axis P1, and the second end is pivotally coupled to base frame 35 at a lower pivot axis P2. Load cell 82 has a mounting portion fixed to support frame 36 (see, e.g., FIG. 17), as described further below.

[0017] A load cell 82 (in some versions, there may be only one) coupled to the head-end leg 78 acts between the head-end lift 72 and the support frame 36. A load cell 82 (in some versions, there may be only one) coupled to the foot-end leg 80 acts between the foot-end lift 74 and the support frame 36. The pivotal connections between the legs 78, 80 and the load cell 82 and / or between the legs 78, 80 and the base frame 35 may be formed using any suitable bracket, pivot pin, pivot shaft, or any other suitable pivotal connection. The legs 78, 80 are operably coupled to their respective actuators 76, 77 and are moved by the respective actuators 76, 77 to pivot about an upper pivot axis P1 relative to the load cell 82 and about a lower pivot axis P2 relative to the base 34. In some versions, the lifts 72, 74 each may include a single leg. In some versions, other types of lift members capable of raising and lowering the support frame 36 can be used.

[0018] Each of the lifts 72, 74 includes a guided body B1, B2 pivotally connected to the second end of the leg 78, 80 by a pivot connection about the lower pivot axis P2. One guided body B1, B2 is provided for each leg 78, 80 (only two guided bodies B1, B2 are visible in FIGS. 2-4B). In the version shown, the guided body B1, B2 includes a block formed of a low-friction material, such as polytetrafluoroethylene (PTFE), to limit friction as the block translates relative to the base 34. The block can be any shape, including box-like, spherical, cylindrical, etc. In some versions, the guided body includes a roller, pin, shaft, gear, or other movable element that moves longitudinally.

[0019] The base 34 includes a pair of head-end guides 84 and a pair of foot-end guides 86 fixed to the base frame 35 for receiving guided bodies B1, B2 (again, only two guides are visible in FIGS. 2-4B). The guided bodies B1, B2 are configured to translate longitudinally within the guides 84, 86 during operation of the lifts 72, 74. Due to the pivotal connection of the guided bodies B1, B2 to the legs 78, 80, the guides 84, 86 act to guide the translational movement of the second ends of the legs 78, 80 during operation (compare FIGS. 2 and 3). The head-end guide 84 guides the movement of the guided body B1, which is pivotally connected to the head-end leg 78. The foot-end guide 86 guides the movement of the guided body B2, which is pivotally connected to the foot-end leg 80.

[0020] The head-end guide 84 includes a head-end guide track 92, and the foot-end guide 86 includes a foot-end guide track 94. The guide tracks 92, 94 are shaped to receive the guided bodies B1, B2. The guide tracks 92, 94 are fixed to the base frame 35 and have an elongated shape. In particular, the guide tracks 92, 94 are shown as rectangular boxes with openings facing inward from the base frame 35. The guide tracks 92, 94 have upper and lower walls W that vertically restrain the guided bodies B1, B2, limiting their movement to sliding within the guide tracks 92, 94. In some versions, the guide tracks 92, 94 can have flanges extending from the upper and lower walls W to capture the guided bodies B1, B2 within the guide tracks 92, 94 and prevent them from being laterally pulled out of the guide tracks 92, 94. In the version shown, the guide tracks 92, 94 are horizontally positioned, although other configurations are contemplated. The guide tracks 92, 94 may be arcuate, linear, or a combination thereof. The guide tracks 92, 94 may be shaped and / or positioned to facilitate both longitudinal and vertical movement of the guided bodies B1, B2. The guide tracks 92, 94 are plain bearing guide tracks along which the blocks slide, and may similarly be formed or coated with a low-friction material, such as PTFE-coated metal or at least one of other low-friction materials.

[0021] 2, the legs 78, 80 pivot relative to the guided bodies B1, B2 as they move longitudinally within the guide tracks 92, 94. To this end, the legs 78, 80 are pivotally and slidably coupled to the base frame 35. The guide tracks 92, 94 and the legs 78, 80 are positioned such that the guided body B1 moves toward the guided body B2 when the support frame 36 is lowered relative to the base 34 and moves away from each other when the support frame 36 is raised relative to the base 34 (compare FIGS. 2 and 3). In some versions, the guide tracks 92, 94 and the legs 78, 80 can be positioned such that the motion of the guided bodies B1, B2 is reversed during raising and lowering. The guide track 92 and guided body B1 associated with the head-end leg 78 are best seen in FIG. 5A - the guide track 94 and guided body B2 associated with the foot-end leg 80 may be similar in shape, size, and placement with respect to the head-end leg 78.

[0022] The actuators 76, 77 can be mounted in any suitable location for actuating the lifts 72, 74. In the version shown in FIGS. 1-5A, the actuator 76 is a rotary actuator having a housing 100a secured to the head-end leg 78 and a rotary shaft 102a secured to at least one of a pair of links 110, as described further below. The rotary shaft 102a can be secured to both links 110 through the housing 100a. The housing 100a includes a motor M (see FIG. 5A) and a gear train operable to rotate the rotary shaft 102a about pivot axis P7. The rotary shaft 102a rotates relative to the housing 100a, thereby rotating the link 110 relative to the head-end leg 78. Alternatively, the housing 100a can be secured to the link 110, and the rotary shaft 102a can be secured to the head-end leg 78. Other suitable locations for the rotary actuator are possible.

[0023] The actuator 76 can also be positioned as shown in FIGS. 5B and 5C to operate between the head-end legs 78 and the links 110. In this version, a first end of the actuator 76 is pivotally connected to the links 110, e.g., directly to one of the links 110 or to a bracket of the cross member 95 (see FIG. 5B) fixed to the links 110 and extending between them. A second end of the actuator 76 is pivotally connected to the head-end legs 78, e.g., directly to one of the head-end legs 78 or to a bracket 106 of the head-end support member 96 (see FIG. 5B) fixed to the head-end legs 78 and extending between them. In this version, the actuator 76 is a linear actuator including a housing 100 and a drive rod 102 that telescopes relative to the housing 100 to rotate the link 110 relative to the head-end legs 78. The housing 100 and drive rod 102 may be pivotally connected to the link 110 and leg 78 via a bracket, a pivot pin, a pivot shaft, or any other suitable pivot connection.

[0024] In the various versions shown, the actuator 76 is disposed without any connection to the base 34 or support frame 36. In the various versions shown, the first lift 72 is a free-standing lift. During movement to the Trendelenburg position, as described further below, the first lift 72 slides longitudinally relative to the second lift 74. As a result, the actuator 76 also slides longitudinally, including both the housings 100 a, 100 and the rotation shafts / drive rods 102 a, 102, which slide toward the second lift 74.

[0025] Referring again to FIG. 2 , the actuator 77 has a first end pivotally connected to the base frame 35. More specifically, the actuator 77 includes a housing 100 and a drive rod 102 that telescopes relative to the housing 100, with the housing 100 pivotally connected at the first end to the base frame 35 via a base bracket 104. The base bracket 104 is fixed to the base frame 35 (e.g., by fasteners, welding, etc.). The first end of the actuator 77 pivots about a pivot axis P3 that is fixed relative to the base frame 35. The pivot axis P3 is defined by the base bracket 104 via a pivot pin, pivot shaft, or any other suitable connection. The actuator 77 extends from the first end to a second end that is pivotally connected to the foot-end leg 80 via a support bracket 106. The support bracket 106 is fixed to the foot-end support member 98 (see FIG. 1 ). The support bracket 106 is secured to the foot-end support member 98 by fasteners, welding, or the like. The second end of the actuator 77 pivots about a pivot axis P4 defined by the support bracket 106 via a pivot pin, pivot shaft, or any other suitable pivot connection. In the version shown, the head-end support member 96 interconnects the second ends of a pair of head-end legs 78, and the foot-end support member 98 interconnects the second ends of a pair of foot-end legs 80 (see FIGS. 1 and 5). As such, the support members 96, 98 act as cross-supports rigidly secured to their respective legs 78, 80 for movement therewith. The support members 96, 98 can be secured to their respective legs 78, 80 in any suitable manner, such as by fasteners, welding, or the like. Therefore, any force applied to the support bracket 106 via the actuator 77 is transferred to the foot end leg 80 due to the rigid connection of the support bracket 106 to the foot end leg 80 .

[0026] Actuator 77 can also be a rotary actuator positioned relative to foot-end leg 80 and link 108 in the same manner as actuator 76 shown in Figure 5A is positioned relative to head-end leg 78 and link 110. Instead of acting between foot-end leg 80 and link 108, actuator 77 can be positioned like actuator 76 shown in Figures 5B and 5C. Numerous actuator types and positions are possible for operating lifts 72, 74 to raise and lower support frame 36 relative to base 34.

[0027] Actuators 76, 77 are operatively coupled to the respective legs 78, 80 to longitudinally move the second ends of the respective legs 78, 80 via guides B1, B2 and guide tracks 92, 94 and pivot the respective legs 78, 80 (by their pivotal connections) about upper and lower pivot axes P1, P2 to raise and lower the support frame 36 relative to the base 34. The actuators 76, 77 include linear actuators, rotary actuators, or other types of actuators. The actuators 76, 77 can be electric, hydraulic, electro-hydraulic, pneumatic, or the like. The actuators 76, 77 can include motors, gear trains, drive screws, nuts / lead screws, etc. for actuation. In the version shown, the actuators 76, 77 are electric motor-driven actuators.

[0028] 2, one or more first links 108 are pivotally connected to the foot-end leg 80 at a first end and extend from the first end to a second end pivotally connected to the base 34. In the version shown, two first links 108 are pivotally connected to the foot-end leg 80 for pivoting about a pivot axis P5 that moves with the foot-end leg 80 (only one first link 108 is shown in FIGS. 2-4B). Each of the first links 108 is pivotally connected to the base frame 35 for pivoting about a pivot axis P6 that is fixed relative to the base frame 35. The pivotal connections for the first links 108 can be formed by pivot pins, pivot shafts, or any other suitable pivotal connections. The pivot axis P5 is in-line with and midway between the upper and lower pivot axes P1, P2 for the foot-end leg 80.

[0029] In some versions, because the first link 108 is pivotally connected to the foot-end leg 80 and the base frame 35, and because the upper pivot axis P1 is fixed to the support frame 36, the first link 108 controls and somewhat restricts the movement of the support frame 36 during lifting and lowering (although some small relative movement can be tolerated by the load cell 82). Comparing FIGS. 2 and 3, note that the upper pivot axis P1 remains vertically aligned with the lower pivot axis P2 during lifting and lowering. Furthermore, when the lifts 72, 74 operate independently to place the support frame 36 in the Trendelenburg position, as shown in FIGS. 4A and 4B, the first link 108 acts to prevent the foot-end upper pivot axis P1 from shifting vertically relative to the base 34. Conversely, the head-end upper pivot axis P1 shifts vertically.

[0030] One or more second links 110 are pivotally connected at a first end to the head-end leg 78 and extend from the first end to a second end pivotally connected to the base 34. In the version shown, two second links 110 are pivotally connected to the head-end leg 78 for pivoting about pivot axis P7, which moves with the head-end leg 78 (only one second link 110 is shown in FIGS. 2-4B ). The second links 110 are also pivotally connected to the base frame 35 for pivoting about pivot axis P8. Unlike the first link 108 and pivot axis P6, pivot axis P8 is not fixed relative to the base frame 35 but can move longitudinally relative to it. The guided body B3 is pivotally connected at a second end of the second link 110 about pivot axis P8 for sliding within the guide 112. The guided body B3 and guide 112 may be similar to those described above and allow the second end of the second link 110 to slide relative to the base 34 (see also FIG. 5A). The pivot connection for the second link 110 may be formed by a pivot pin, a pivot shaft, or any other suitable pivot connection. The pivot axis P7 is aligned with and midway between the upper pivot axis P1 and the lower pivot axis P2 for the head-end leg 78. The actuator 76 for the head-end lift 72 is operably coupled to the second link 110, as described above.

[0031] As discussed above, when the lifts 72, 74 operate independently to set the support frame 36 in the Trendelenburg position, the first link 108 acts on the foot-end lift 74 to prevent the foot-end upper pivot axis P1 from shifting vertically relative to the base 34, while the head-end upper pivot axis P1 shifts vertically. The second link 110 also shifts vertically, as shown in FIGS. 4A and 4B. More specifically, when either or both of the actuators 76, 77 operate to set the support frame 36 and patient support deck 38 in one or more Trendelenburg positions, the pivot axis P8 moves vertically to remain aligned with the head-end upper pivot axis P1. (Compare the vertical line V1 in FIG. 2 created by the pivot axes P1, P8 prior to moving to the Trendelenburg position with the vertical line V2 shown in FIG. 4A.) Therefore, the guided body B3 moves in the guide 112 in the vertical direction relative to the base 34 toward the foot end.

[0032] As shown in FIG. 4A , when moving to the Trendelenburg position, the horizontal longitudinal distance between the upper pivot axis P1 and the pivot axes P6 and P8 decreases (compare horizontal distance D1 with horizontal distance D2). The head-end lift 72 slides toward the foot-end lift 74 to accommodate the movement of the support frame 36 into one or more Trendelenburg positions. This occurs when the support frame 36 and patient support deck 38 are placed in any of the Trendelenburg positions shown in FIGS. 4A and 4B . Therefore, movement of either or both of the lifts 72 and 74 to place the support frame 36 and patient support deck 38 in the Trendelenburg position moves the upper pivot axis P1 associated with the head-end lift 72 vertically closer to the foot end. Similarly, pivot axis P8 and the associated guided body B3 also move vertically closer to the foot end. Additionally, the lower pivot axis P2 and corresponding guided body B1 associated with the head-end lift 72 move vertically closer to the foot-end. For example, comparing Figures 2 and 4A, when the foot-end lift 74 is actuated to set the support frame 36 and patient support deck 38 in the Trendelenburg position of Figure 4A, the head-end lift 72 slides entirely toward the foot-end lift 74 while remaining in the same configuration. In other words, the head-end leg 78, second link 110, guided body B1, guided body B3, and actuator 76 all move vertically a distance equal to (D1 - D2).

[0033] Another lift system that can be used on the patient support apparatus 30 is shown in U.S. Provisional Patent Application No. 62 / 948,540, filed December 16, 2019, entitled "Patient Support With Lift Assembly," which is incorporated herein by reference.

[0034] 6-8 show another lift system 170 that operates to raise and lower the support frame 36 and patient support deck 38 relative to the base 34 in much the same manner as lift system 70. Lift system 170 is configured to move the support frame 36 between various heights relative to the base 34. Lift system 170 includes a head-end lift 172 and a foot-end lift 174. Head-end lift 172 is positioned to raise or lower the head end of the support frame 36 relative to the base 34. Foot-end lift 174 is positioned to raise or lower the foot end of the support frame 36 relative to the base 34. Head-end lift 172 and foot-end lift 174 each include actuators 176, 177 that operate lifts 172, 174, respectively. The lifts 172, 174 are operable separately and independently, allowing the support frame 36 and patient support deck 38 to be set in one or more Trendelenburg positions, with the head and foot ends at different heights relative to the base 34, as shown in Figures 7A and 7B.

[0035] The head-end lift 172 and foot-end lift 174 may be interchangeable such that the head-end lift 172 is at the foot end of the patient support apparatus 30 and the foot-end lift 174 is at the head end of the patient support apparatus 30. Figures 6-7B are elevational schematic diagrams illustrating the lifts 172, 174 and their operation. The mattress 40, side rails 44, 46, 48, 50, headboard 52, and footboard 54 have been omitted from Figures 6-7B for purposes of illustration.

[0036] In this version, the head-end lift 172 includes a head-end column lift 178 extending between a pair of first load cells 82 and the base 34 (only one of the pair of load cells 82 is shown in FIGS. 6-7B). An actuator 176 is positioned to extend and retract the head-end column lift 178. The head-end column lift 178 is fixed so as not to slide relative to the base 34 and has a base portion 179 fixed to the base frame 35. The foot-end lift 174 includes a foot-end column lift 180 extending between the pair of second load cells 82 and the base 34 (only one of the pair of load cells 82 is shown in FIGS. 6-7B). An actuator 177 extends and retracts the foot-end column lift 180. The foot-end lift 174 is allowed to slide relative to the base 34 and the head-end lift 172 to accommodate movement of the support frame 36 into one or more Trendelenburg positions, as described further below.

[0037] The column lifts 178, 180 telescope vertically in a telescopic fashion. The end of the head-end column lift 178 is pivotally connected to a pair of first load cells 82 at an upper pivot axis P1. The end of the foot-end column lift 180 is pivotally connected to a pair of second load cells 82 at an upper pivot axis P1. The pivot connection between the column lifts 178, 180 and the load cells 82 can be formed using any suitable bracket, pivot pin, pivot shaft, or any other suitable pivot connection. See, for example, pivot shafts 187, 189 connecting the column lifts 178, 180 to the load cells 82 in FIG. 8 . In some versions, the column lifts 178, 180 can be in the form of linear actuators, such as the actuator 77 described above, positioned and mounted for vertical movement. The column lifts 178, 180 can be telescopic hydraulic jacks. The column lifts 178, 180 may be as described in U.S. Patient Support Platform U.S. Patient Support Platform No. 6,820,294, filed February 26, 2002, entitled "Linkage For Lift / Lowering Control For A Patient Support Platform," or as described in U.S. Patient Support Platform No. 7,395,564, filed March 24, 2006, entitled "Articulated Support Surface For A Stretcher Or Gurney," both of which are incorporated herein by reference.

[0038] Foot end column lift 180 includes a guided body B4 that supports foot end column lift 180 during movement into one or more Trendelenburg positions, as shown in FIGS. 7A and 7B. In the version shown, guided body B4 includes a cart 184 having wheels 186. Cart 184 is secured to base portion 181 of foot end column lift 180. Base 34 provides a guide 188 that receives cart 184. Guide 188 includes a guide track 190 that confines movement of cart 184 within guide track 190. Guide track 190 is defined by a bottom wall that supports cart 184 and wheels 186 and one or more side walls that confine movement of cart 184, thereby constraining movement to a vertical direction during movement into one or more Trendelenburg positions.

[0039] Because the column lifts 178, 180 are pivotally connected to the upper pivot axis P1, which is fixed relative to the support frame 36, and because the head-end column lift 178 has its base portion 179 fixed to the base frame 35, the guided body B4 is configured to translate vertically within the guide 188 during movement of either or both of the lifts 172, 174 to place the support frame 36 and the patient support deck 38 in the Trendelenburg position (compare FIGS. 6 and 7A or 7B). Once the support frame 36 and the patient support deck 38 have moved into the Trendelenburg position, the guided body B4, and more specifically the foot-end lift 174, slides toward the head-end lift 172, as shown by the arrows in FIGS. 7A and 7B. When the lifts 172, 174 simultaneously operate to raise or lower the support frame 36 while maintaining the support frame 36 horizontal, the guided body B4 remains stationary (not shown).

[0040] Figures 9-11 show the same lift system 170 as shown in Figures 6-8, except that the load cell 82 connected to the head-end column lift 178 has been repositioned so that it is in the same vertical orientation as the other load cell 82 pivotally connected to the foot-end column lift 180. In the version shown in Figures 6-8, the paired load cells 82 are mounted in opposite orientations on the support frame 36. In Figures 9-11, the paired load cells 82 are mounted in the same orientation on the support frame 36.

[0041] 12 and 13 show another alternative arrangement of the load cells 82, in which their mounting portions are fixed to the lifts 172, 174 instead of the support frame 36 and are pivotally connected to the support frame 36 at a pivot connection for pivoting about pivot axis P1 (compare FIGS. 12 and 13 to see the pivoting movement). As a result, the load cells 82 remain substantially horizontal, parallel to the longitudinal axis L1 of the base 34, during movement of the support frame 36 into one or more Trendelenburg positions (see FIG. 13). Conversely, in the version shown in FIGS. 1-11, the load cells 82 are positioned to tilt with the support frame 36 during movement of the support frame 36 into one or more Trendelenburg positions.

[0042] 14 and 15 show another alternative arrangement of the load cells 82, in which the foot-end load cells 82 have mounting portions fixed to the guided body B4 so as to slide relative to the foot-end lift 174. In this version, both lifts 172, 174 are fixed so as not to slide vertically, even during movement of the support frame 36 into one or more Trendelenburg positions. Instead, the foot-end load cells 82 slide with the guided body B4 relative to the foot-end lift 174 by means of a sliding mechanism (shown, for example, as multiple rollers). In this version, all of the load cells 82 remain horizontal during movement of the support frame 36 into one or more Trendelenburg positions.

[0043] 16 , a control system for controlling the operation of the actuators 76, 77, 176, and 177 is shown. The control system includes a controller 200 having one or more processors. The processor processes instructions or algorithms stored in memory to control the operation of the actuators 76, 77, 176, and 177, either coordinating the movement of the actuators 76, 77, 176, and 177 to uniformly raise and lower the support frame 36 relative to the base 34, or independently operating the actuators 76, 77, 176, and 177 to place the support frame 36 in a Trendelenburg position, such as normal or reverse Trendelenburg. Additionally or alternatively, the controller 200 may include one or more of a microcontroller, microprocessor, field programmable gate array, system-on-chip, discrete circuitry, and / or other suitable hardware, software, or firmware capable of performing the functions described herein. The controller 200 may be mounted on the patient support apparatus 30 or may be remotely located. In some versions, the controller 200 is mounted to the base 34. In some versions, the controller 200 is mounted to the footboard 54. Power for the actuators 76, 77, 176, 177 and / or the controller 200 may be provided by a battery power source and / or an external power source.

[0044] The controller 200 is coupled to the actuators 76, 77, 176, and 177 such that the controller 200 can control the actuators 76, 77, 176, and 177. The controller 200 can communicate with the actuators 76, 77, 176, and 177 via wired or wireless connections to perform one or more desired functions. The controller 200 can monitor the current state of the actuators 76, 77, 176, and 177 via one or more sensors and determine a desired state to which the actuators 76, 77, 176, and 77 should be set based on one or more input signals received by the controller 200 from one or more user input devices. The state of the actuators 76, 77, 176, and 177 can be the position, relative position, angle, power status (e.g., on / off), or any other parameter of the actuators 76, 77, 176, and 177.

[0045] A user, such as a caregiver, can activate one or more user input devices 202, which send corresponding input signals to the controller 200, which controls the operation of the actuators 76, 77, 176, and 177 based on the input signals. The user input devices 202 can include any device operable by a user and may be provided on a control panel, touch screen, or the like. The user input devices 202 can be configured to be activated in a variety of different ways, including, but not limited to, mechanical activation (e.g., hand, foot, finger), hands-free activation (e.g., voice, foot), and the like. The user input devices 202 can include buttons (e.g., buttons corresponding to raise, lower, normal Trendelenburg, and reverse Trendelenburg), gesture detection devices for monitoring the movement of the user's hands, feet, or other body parts (e.g., via a camera), microphones for receiving voice-activated commands, foot pedals, and sensors (e.g., infrared sensors, ultrasonic sensors, capacitive sensors, etc., such as a light bar or light beam that detects the user's body parts). Additionally, the buttons / pedals can be physical buttons / pedals or virtually implemented buttons / pedals, such as through optical projection or on a touchscreen. The buttons / pedals can also be mechanically connected buttons / pedals or drive-by-wire type buttons / pedals in which user-applied force activates a sensor, such as a switch or potentiometer. It should be understood that any combination of user input devices can be utilized. The user input devices can be located on one of the side rails 44, 46, 48, 50, the headboard 52, the footboard 54, or other suitable locations. The user input devices can also be located on a portable electronic device (e.g., an iWatch®, iPhone®, iPad®, or similar electronic device).

[0046] In operation, when a user desires to move the support frame 36 relative to the base 34, the user actuates one or more of the user input devices 202. For example, if the user desires to lower the support frame 36 relative to the base 34, e.g., to move the support frame 36 from the position shown in Figure 2 to the position shown in Figure 3, the user actuates the appropriate user input device 202 (e.g., see touchscreen button 202b). Upon actuation, the controller 200 sends output signals to the actuators 76, 77, causing simultaneous operation of the actuators 76, 77 to lower the support frame 36.

[0047] The control system may also include a scale for indicating the patient's weight and / or for detecting the patient's position / movement on the patient support apparatus 30, such as in conjunction with a bed exit alarm system. The scale includes load cells 82 connected to the controller 200 to provide a signal related to the load measured by each of the load cells 82. For example, each load cell 82 may include a pair of actuation leads and a pair of sensor leads. The controller 200 may include circuitry in communication with the actuation leads to power the load cell 82 through one of the actuation leads, with the other actuation lead coupled to ground. The controller 200 may also be in communication with a sensor lead that provides an output to the controller 200 that correlates to how much force is being applied to the load cell 82. See, for example, the description of load cells in U.S. Patent Application No. 16 / 549,612, filed August 23, 2019, entitled "Angle Calibration Using Load Cells," which is incorporated herein by reference.

[0048] The output signals received from the load cells 82 via their sensor leads can be collectively processed by the controller 200 using a scale algorithm to determine the patient's weight for output to a display 206, as shown in FIG. 16 . See, for example, the method described in U.S. Patent Application Serial No. 16 / 549,612, entitled “Angle Calibration Using Load Cells,” which is incorporated herein by reference. The scale can include a tare function 208 and a converter 210 for switching between kilograms and pounds. In some versions, by mounting the load cells 82 between the lifts 72, 74, 172, 174 and the support frame 36, the lifts 72, 74, 172, 174 are not part of the tare weight, thereby reducing the tare weight compared to patient support apparatus that rely on a separate lightweight frame located below the lift.

[0049] FIG. 17 shows one arrangement of load cells 82 from the patient support apparatus 30 of FIGS. 1-5. In the version shown, pair 82a of load cells 82 is coupled to head-end leg 78, and pair 82b of load cells 82 is coupled to foot-end leg 80. The load cells 82 are arranged so that a load applied to the support frame 36 is transferred to the plurality of load cells 82 for measurement. Portion 36a of support frame 36 to which load cells 82 are attached by one or more fasteners is shown in FIG. 17. Load cells 82 can be attached to support frame 36 by fasteners, welding, or the like. First ends of legs 78, 80 are shown pivotally connected to a respective pair of load cells 82 by pivot shafts 212.

[0050] Each of the load cells 82 includes an elongated body 214 extending longitudinally along a longitudinal axis L2 from a mounting portion 216 to a load-application portion 218. The mounting portion 216 is fixedly attached to a portion 36a of the support frame 36, as shown in FIG. 17. In the version shown, each of the plurality of load cells 82 is disposed longitudinally between the head end and foot end of the support frame 36. The lifts 72, 74 are pivotally connected to the load-application portion 218 of the load cell 82 by the corresponding legs 78, 80 of the lifts being pivotally connected to the load-application portion 218 at pivot axis P1. In some versions, the mounting portion 216 is fixedly attached to the lifts 72, 74, 172, 174, and the load-application portion 218 is pivotally connected to the support frame 36 (see, e.g., FIGS. 12 and 13). 17, the pair 82a, 82b of load cells 82 are shown aligned and oriented vertically so that their load-applying portions 218 face in opposite directions. In some versions, as shown in FIGS. 9-11, the pair 82a, 82b of load cells 82 are aligned and oriented vertically so that their load-applying portions 218 face in the same direction.

[0051] One of the load cells 82 is shown in more detail in FIGS. 18-27. In some versions, the load cells 82 are identical. In some versions, the load cells may vary in type, shape, size, resolution, etc. One type of load cell 82 will now be described in more detail. Referring to FIGS. 18-22, a beam-type load cell is shown. The mounting portion 216 of the load cell 82 includes a pair of bores 221 that receive fasteners for attaching the mounting portion 216. The load-application portion 218 of the load cell 82 receives a pivot shaft 212 that may be used to connect, for example, one of the legs 78, 80 to the load cell 82. The elongated body 214 of the load cell 82 also includes upper and lower beams 224, 226 that connect the load-application portion 218 to the mounting portion 216. As best seen in FIGS. 20-22, one or more upper strain gauges 228 are coupled to the upper beam 224 and one or more lower strain gauges 230 are coupled to the lower beam 226 .

[0052] 20-22, the beams 224, 226 and strain gauges 228, 230 are positioned such that the strain gauges 228, 230 are more sensitive to loads applied transverse to the longitudinal axis L2 than to loads applied along the longitudinal axis L2. Ideally, the load is applied only vertically, perpendicular to the longitudinal axis L2 (see "vertical load"). Under such a load, the upper beam 224 is placed in tension and the lower beam 226 is placed in compression, or vice versa, depending on the direction of the vertical load. Under compression, the upper strain gauge 228 has a positive polarity and the lower strain gauge 230 has a negative polarity. As a result, the upper and lower strain gauges 228, 230 are twice as sensitive to vertical loads and properly measure the applied load.

[0053] During load measurement, if there is a longitudinal load ("end load") applied along the longitudinal axis L2 precisely centered between the beams 224, 226, both beams are placed in equal tension or compression, and the associated effects on the strain gauges 228, 230 are substantially canceled due to the opposite polarity of the strain gauges 228, 230. Therefore, the end load acting on the load cell 82 can be effectively ignored by the load cell 82. However, if the end load is vertically offset from the longitudinal axis L2, the associated effects on the strain gauges 228, 230 may be amplified rather than effectively canceled due to the opposite polarity of the strain gauges 228, 230. Loads applied laterally across the longitudinal axis L2 (see "side load") can also be undesirable and difficult to compensate for during measurement. These loads cause complex shear / tension / compression loads in the strain gauges 228, 230. Twisting of the load cell 82 about the longitudinal axis L2 is also undesirable and causes internal shear loads in the strain gauges 228, 230 in opposite directions to the beams 224, 226. Such twisting can be difficult to compensate for during measurements and can result in inaccurate readings. For these reasons, it can be desirable to minimize side loads and twisting of the load cell 82.

[0054] 23, the load cell 82 includes a bushing 232 shaped and configured to minimize side load and twisting of the load cell 82 and to concentrate the application of the load over a small load application area R. The bushing 232 defines a pair of side openings 234 and a pivot shaft passage 236 extending between the side openings 234. The pivot shaft passage 236 receives the pivot shaft 212. Each of the side openings 234 has a first diameter D1, and the pivot shaft passage 236 has a second diameter D2 in the load application area R. The second diameter D2 is smaller than the first diameter D1.

[0055] The load application region R is located midway through the pivot shaft passage 236 and has a width W that is less than 50% of the length LN of the pivot shaft passage 236, less than 30% of the length LN of the pivot shaft passage 236, or less than 10% of the length LN of the pivot shaft passage 236. The load application region R defines a plane having a width W along which a load is concentrated. In some versions, the load application region R has a width W that is less than 1.0 inch, less than 0.6 inch, less than 0.4 inch, or less than 0.3 inch. The elongate body 214 defines a vertical plane VP that extends midway (center) of the elongate body 214, the vertical plane VP passing through the center of the load application region R. Thus, the load application region R represents a relatively narrow region centered within the pivot shaft passage 236 where a load is ideally applied to the load cell 82.

[0056] The pivot shaft passage 236 tapers from a first diameter D1 at each of the pair of side openings 234 to a second diameter D2 at the load application region R. The taper may form an angle α with respect to the central axis CA of the pivot shaft passage 236 of at least 3 degrees, at least 5 degrees, at least 10 degrees, or at least 15 degrees. The taper between the side openings 234 and the load application region R provides free space to accommodate the pivot shaft 212 when tilt of the pivot shaft 212 with respect to the central axis CA occurs within the pivot shaft passage 236. This free space allows the pivot shaft 212 to tilt to at least a limited extent before a torsional load is perceived by the strain gauges 228, 230.

[0057] 24 , elongated body 214 includes a block 238, and bushing 232 is coupled to block 238 to define pivot shaft passage 236. Block 238 defines a throughbore 240, and bushing 232 is located within throughbore 240. Bushing 232 has a central bushing portion 244 and side bushing portions 246. Bushing 232 may be insert molded within throughbore 240, press fit within throughbore 240 (by first softening bushing 232 and then inserting it), formed in two pieces and fastened / glued together within throughbore 240, or otherwise disposed within throughbore 240. Block 238 is at least partially formed of metal, and bushing 232 is at least partially formed of plastic. The bushing 232 may be formed, coated, or both, at least in part, from a low friction and low wear material, such as PTFE, to facilitate movement of the pivot shaft 212 within the bushing 232.

[0058] Referring to FIG. 24A, an alternative block 238a and bushing 232a are shown having interlocking features 241, 243 to facilitate connection. The interlocking features can include an annular detent rib 241 that fits into annular detent pocket 243. Other types of snap-fit ​​connections are also contemplated. In some cases, there can be a single set or multiple sets (as shown) of such interlocking features. Additionally or alternatively, bushing 232a can be press-fit into block 238a. In FIG. 24A, bushing 232a is shown as being two-piece with a separate cap 245. Cap 245 can be attached around the end of bushing 232a once the other piece of bushing 232a is inserted through block 238a. Once cap 245 is attached, the resulting bushing 232a resembles bushing 232 shown in FIG. 24. The cap 245 can be attached by at least one of welding, fasteners, adhesives, and / or a press fit.

[0059] 25A-25C, block 238 has a side surface 242 from which a side bushing portion 246 extends and abuts against a pivot bracket 248, such as a pivot bracket of legs 78, 80 that is pivotally connected to load cell 82 by pivot shaft 212 (see FIG. 25B). FIG. 25C illustrates the effect of a slight tilt of pivot shaft 212, but without causing a corresponding twist in load cell 82 (due to the tapered shape of pivot shaft passage 236). Thus, a load acting on pivot shaft 212 is still applied predominantly in load application region R and in a vertical and / or end direction.

[0060] In some of the arrangements of load cell 82 described above, load cell 82 tilts with support frame 36 during movement into Trendelenburg (see, for example, FIG. 4A). However, the edge loads that would normally occur during such tilting are minimized because head end lift 72 (or foot end lift 74 in some versions) is configured to slide and compensate for such tilting movement by their translation along guided bodies B1, B2, B4 and base 34. Because load cell 82 is aligned vertically with respect to support frame 36, it further takes advantage of the fact that load cell 82 is insensitive to edge loads.

[0061] FIG. 26 illustrates the tilting of two of the load cells 82 (one load cell attached to the head-end leg 78 and the other load cell attached to the foot-end leg 80). FIG. 26 illustrates the application of the resulting loads F1 and F2 acting on the load cells 82 through the pivot shaft 212. Due to the tilting of the load cells 82, the loads F1 and F2 are applied at an angle relative to the longitudinal axis L2 of the load cells 82; however, the loads F1 and F2 are still applied along the plane defined by the load application area R for the reasons discussed above. Each of the loads F1 and F2 has a vertical component FV oriented perpendicular to the longitudinal axis L2 and a vertical component FL oriented parallel to the longitudinal axis L2. Because the application of the vertical component FL is not exactly along the longitudinal axis L2, there may be some uncountered end load effect on the strain gauges 228 and 230 for each particular load cell 82. However, because the load cells 82 are mounted in opposite orientations, the collective effects on the load cells 82 tend to cancel. As a result, the measured load is substantially based on the vertical components FV of the loads F1 and F2.

[0062] A simple correction can be applied to the measurements made by each load cell 82 to determine the loads F1 and F2. This correction is calculated by measuring the angle of the load cell 82 (e.g., the Trendelenburg angle can be measured by an accelerometer, gyroscope, tilt sensor, or other suitable means connected to the controller 200), simply determining the loads F1 and F2 based on a cosine function of the measured angle, and applying the cosine function to the measured load (e.g., FV). The correction factor is based on the relationship L=W·cos(T), where L is the collective measurement of the load, W is the total patient weight, and T is the Trendelenburg angle. See, for example, the correction algorithm and related components described in U.S. Patent Application No. 16 / 549,612, entitled "Angle Calibration Using Load Cells," which is incorporated herein by reference. However, such a correction would not be required with the load cell 82 arrangement shown in FIGS. 12 and 13. This is because the load cells 82 maintain their substantially horizontal orientation (+ / - 5 degrees) during tilting of the support frame 36 when moving the support frame 36 into one or more Trendelenburg positions, so that the loads F1 and F2 in that orientation are applied substantially vertically.

[0063] FIG. 27 shows a version of the load cell 82 in which the block 338 of the load cell 82 is shaped to provide a tapered pivot shaft passage 336, such as that provided by the bushing 232 described above, resulting in a small load application area R onto which the load from the pivot shaft 212 can be concentrated.

[0064] Several versions have been discussed in the above description. However, the versions discussed herein are not intended to be exhaustive or to limit the invention to the particular forms. The terminology used is intended to be in the nature of words of description rather than words 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.

[0065] The present disclosure also includes the following clauses, together with specific features set forth in the dependent clauses, which may be specifically implemented as described in more detail with reference to the above configurations and drawings. Terms I. A patient support device comprising: a support structure including a base, a support frame, and a patient support deck, the support frame extending longitudinally from a first longitudinal end to a second longitudinal end, the base having a guide; a first lift that raises or lowers the first vertical end portion of the support frame relative to the base, the first lift having a guided body that is movable in a vertical direction relative to the base along the guide; a second lift for raising or lowering the second longitudinal end of the support frame relative to the base, the first lift and the second lift being independently operable to set the support frame in one or more Trendelenburg positions in which the first longitudinal end and the second longitudinal end are at different heights relative to the base; a plurality of load cells, the plurality of load cells including at least one load cell coupled to the first lift for acting between the first lift and the support frame, and at least one load cell coupled to the second lift for acting between the second lift and the support frame, such that a load on the support frame is transmitted to the plurality of load cells for measuring the load; A patient support device wherein the guided body is arranged to move in the longitudinal direction relative to the base in response to operation of the second lift to move the support frame into the one or more Trendelenburg positions, whereby the first lift moves in the longitudinal direction toward the second lift to accommodate movement of the support frame into the one or more Trendelenburg positions. II. The patient support apparatus of clause I, wherein the first vertical end is further defined as one of a head end and a foot end, and the second vertical end is further defined as the other of the head end and the foot end. III. The patient support apparatus of clause II, wherein each of the plurality of load cells includes an elongated body extending in the longitudinal direction from a mounting portion to a load-application portion. IV. The patient support apparatus of clause III, wherein each of the plurality of load cells is positioned in the longitudinal direction between the head end and the foot end of the support frame. V. The patient support apparatus of clause IV, wherein the at least one load cell coupled to the first lift is further defined as a pair of first load cells, and the at least one load cell coupled to the second lift is further defined as a pair of second load cells. VI. A patient support apparatus as described in clause V, wherein the first lift is pivotally connected to the load-applying portion of the pair of first load cells, the second lift is pivotally connected to the load-applying portion of the pair of second load cells, the mounting portions of the pair of first load cells are fixed to the support frame, and the mounting portions of the pair of second load cells are fixed to the support frame. VII. A patient support apparatus as described in any one of clauses V-IV, wherein the mounting portions of the pair of first load cells are fixed to the first lift, the mounting portions of the pair of second load cells are fixed to the second lift, the load-applying portions of the pair of first load cells are pivotally connected to the support frame, and the load-applying portions of the pair of second load cells are pivotally connected to the support frame. VIII. The first lift is one or more first legs extending from the pair of first load cells to the base, the one or more first legs slidably coupled to the base for sliding relative to the base; one or more links pivotally connected to the one or more first legs and extending from the one or more first legs to the base; a first actuator operatively coupled to the one or more first legs and the one or more links; Including, A patient support device as described in any one of clauses V to VII, wherein the guided body is pivotally connected to the one or more links, and the guided body is coupled to the base and translates in the vertical direction along the guide relative to the base during movement to the one or more Trendelenburg positions. IX. The second lift one or more second legs extending from the pair of second load cells to the base, the one or more second legs slidably coupled to the base for sliding movement relative to the base; a second actuator operably coupled to the one or more second legs; 8. The patient support apparatus of claim VIII, comprising: X. A patient support apparatus as described in any one of clauses V to IX, wherein the first lift includes a first column lift extending from the pair of first load cells to the base and a first actuator that extends and contracts the first column lift, and the first column lift is fixed so as not to slide relative to the base. XI. The patient support apparatus described in clause X, wherein the second lift includes a second column lift extending from the pair of second load cells to the base and a second actuator for extending and retracting the second column lift, and the guided body is positioned to support the second column lift and translate the second column lift in the vertical direction relative to the base during movement to the one or more Trendelenburg positions. XII. The patient support apparatus of any one of clauses V-XI, wherein the first pair of load cells are longitudinally aligned with the second pair of load cells, and the load application portions of the first pair of load cells and the load application portions of the second pair of load cells are oriented to face in opposite directions. XIII. The patient support apparatus of any one of clauses V-XII, wherein the pair of first load cells are aligned vertically with the pair of second load cells, and the load application portions of the pair of first load cells and the load application portions of the pair of second load cells are oriented to face the same direction. XIV. A patient support apparatus as described in any one of clauses V to XIII, wherein the pair of first load cells and the pair of second load cells are positioned to tilt with the support frame during movement of the support frame into the one or more Trendelenburg positions. XV. The patient support apparatus of any one of clauses V to XIV, wherein the pair of first load cells and the pair of second load cells are positioned to remain substantially horizontal during movement of the support frame into the one or more Trendelenburg positions. XVI. A patient support apparatus as described in any one of clauses I to XV, wherein the guided body is arranged to move in the vertical direction relative to the base in response to operation of the first lift to move the support frame into one or more Trendelenburg positions. XVII. The patient support apparatus of any one of clauses I-XVI, comprising a plurality of side rails coupled to the support structure and a plurality of caster wheels coupled to the base. XVIII. A load cell, an elongated body extending longitudinally along a longitudinal axis from a mounting portion to a load application portion, the load application portion defining a pair of side openings and a pivot shaft passageway extending between the side openings, the load application region being located midway between the pivot shaft passageways; A load cell, wherein each of the pair of side openings has a first diameter, and the pivot shaft passage has a second diameter in the load application region, the second diameter being smaller than the first diameter. XIX. The load cell of clause XVIII, wherein the pivot shaft passage tapers from the first diameter at each of the pair of side openings to the second diameter at the load application region. XX. The load cell of any one of clauses XVIII-XIX, wherein the elongate body defines a plane extending partway through the elongate body, the plane passing through the load application region. XXI. The load cell of any one of clauses XVIII-XX, wherein the elongated body includes a block and a bushing coupled to the block to define the pivot shaft passage, the block being at least partially formed of metal and the bushing being at least partially formed of plastic. XXII. The load cell of clause XXI, wherein the block defines a through hole, and the bushing is positioned within the through hole. XXIII. The load cell of clause XXII, wherein the block has a side surface and the bushing has a central bushing portion located within the through hole and a side bushing portion extending from the side surface. XXIV. The load cell of any one of clauses XVIII-XXIII, wherein the elongated body includes a pair of beams connecting the load application portion to the mounting portion. XXV. The load cell of clause XXIV, wherein a pair of strain gauges are coupled to said pair of beams. XXVI. The load cell of clause XXV, wherein the beam and strain gauges are positioned such that the pair of strain gauges is more sensitive to loads applied transverse to the longitudinal axis compared to loads applied along the longitudinal axis.

Claims

1. 1. A patient support apparatus comprising: a support structure including a base, a support frame, and a patient support deck, the support frame extending from a first longitudinal end to a second longitudinal end, the base having a guide; a first lift that raises or lowers the first vertical end portion of the support frame relative to the base, the first lift having a guided body that is movable in a vertical direction relative to the base along the guide; a second lift for raising or lowering the second longitudinal end of the support frame relative to the base, the first lift and the second lift being independently operable to set the support frame in one or more Trendelenburg positions in which the first longitudinal end and the second longitudinal end are at different heights relative to the base; a plurality of load cells, the plurality of load cells including at least one load cell coupled to the first lift for acting between the first lift and the support frame, and at least one load cell coupled to the second lift for acting between the second lift and the support frame, such that a load on the support frame is transmitted to the plurality of load cells for measuring the load; Equipped with The guided body is arranged to move in the vertical direction relative to the base in response to operation of the second lift to move the support frame into the one or more Trendelenburg positions, whereby the first lift moves in the vertical direction toward the second lift to accommodate movement of the support frame into the one or more Trendelenburg positions.

2. 10. The patient support apparatus of claim 1, wherein the first longitudinal end is further defined as one of a head end and a foot end, and the second longitudinal end is further defined as the other of the head end and the foot end.

3. The patient support apparatus of claim 2 , wherein each of the plurality of load cells includes an elongated body extending in the longitudinal direction from a mounting portion to a load application portion.

4. The patient support apparatus of claim 3 , wherein each of the plurality of load cells is positioned in the longitudinal direction between the head end and the foot end of the support frame.

5. 5. The patient support apparatus of claim 4, wherein the at least one load cell coupled to the first lift is further defined as a pair of first load cells, and the at least one load cell coupled to the second lift is further defined as a pair of second load cells.

6. 6. The patient support apparatus of claim 5, wherein the first lift is pivotally connected to a load-applying portion of the pair of first load cells, the second lift is pivotally connected to a load-applying portion of the pair of second load cells, the mounting portions of the pair of first load cells are fixed to the support frame, and the mounting portions of the pair of second load cells are fixed to the support frame.

7. 6. The patient support apparatus of claim 5, wherein the mounting portions of the first pair of load cells are fixed to the first lift, the mounting portions of the second pair of load cells are fixed to the second lift, the load-applying portions of the first pair of load cells are pivotally connected to the support frame, and the load-applying portions of the second pair of load cells are pivotally connected to the support frame.

8. The first lift includes: one or more first legs extending from the pair of first load cells to the base, the one or more first legs being slidably coupled to the base for sliding movement relative to the base; one or more links pivotally connected to the one or more first legs and extending from the one or more first legs to the base; a first actuator operably coupled to the one or more first legs and the one or more links; Including, the guided body is pivotally connected to the one or more links, and the guided body is coupled to the base and translates in the longitudinal direction along the guide relative to the base during movement to the one or more Trendelenburg positions; The second lift includes: one or more second legs extending from the pair of second load cells to the base, the one or more second legs slidably coupled to the base for sliding movement relative to the base; a second actuator operably coupled to the one or more second legs; The patient support apparatus of claim 5 , comprising:

9. the first lift includes a first column lift extending from the pair of first load cells to the base, and a first actuator that expands and contracts the first column lift, the first column lift being fixed so as not to slide relative to the base; 6. The patient support apparatus of claim 5, wherein the second lift includes a second column lift extending from the pair of second load cells to the base and a second actuator that extends and retracts the second column lift, and the guided body is arranged to support the second column lift and translate the second column lift in the vertical direction relative to the base during movement to the one or more Trendelenburg positions.

10. 6. The patient support apparatus of claim 5, wherein the pair of first load cells are aligned with the pair of second load cells in the longitudinal direction, and the load application portions of the pair of first load cells and the load application portions of the pair of second load cells are oriented facing in opposite directions.

11. 6. The patient support apparatus of claim 5, wherein the pair of first load cells are aligned with the pair of second load cells in the longitudinal direction, and the load application portions of the pair of first load cells and the load application portions of the pair of second load cells are oriented to face in the same direction.

12. 6. The patient support apparatus of claim 5, wherein the first pair of load cells and the second pair of load cells are positioned to tilt with the support frame during movement of the support frame into the one or more Trendelenburg positions.

13. 6. The patient support apparatus of claim 5, wherein the first pair of load cells and the second pair of load cells are positioned to remain substantially horizontal during movement of the support frame into the one or more Trendelenburg positions.

14. 2. The patient support apparatus of claim 1, wherein the guided body is arranged to move in the vertical direction relative to the base in response to operation of the first lift to move the support frame into the one or more Trendelenburg positions.

15. The patient support apparatus of claim 1 , comprising a plurality of side rails coupled to the support structure and a plurality of caster wheels coupled to the base.

16. Each of the plurality of load cells comprises an elongated body extending longitudinally along a vertical axis from an attachment portion to a load application portion, the load application portion defining a pair of side openings and a pivot shaft passage extending between the side openings, the load application region being located midway between the pivot shaft passages; each of the pair of side openings has a first diameter, and the pivot shaft passage has a second diameter in the load application region, the second diameter being smaller than the first diameter; 16. A patient support apparatus according to any one of claims 1 to 15.

17. 17. The patient support apparatus of claim 16, wherein the pivot shaft passage tapers from the first diameter at each of the pair of side openings to the second diameter at the load application region.

18. 17. The patient support apparatus of claim 16, wherein the elongate body defines a plane extending midway through the elongate body, the plane passing through the load application region.

19. the elongated body includes a block and a bushing coupled to the block to define the pivot shaft passage, the block being at least partially formed of metal and the bushing being at least partially formed of plastic; the block defines a through hole, the bushing is positioned within the through hole; 17. The patient support apparatus of claim 16, wherein the block has a side surface, and the bushing has a central bushing portion located within the through hole and a side bushing portion extending from the side surface.

20. the elongated body includes a pair of beams connecting the load application portion to the mounting portion, a pair of strain gauges coupled to the pair of beams; 17. The patient support apparatus of claim 16, wherein the beam and the strain gauges are positioned such that the pair of strain gauges are more sensitive to loads applied transverse to the longitudinal axis compared to loads applied along the longitudinal axis.

Images