Patient transport apparatus having collision avoidance backup power system

Abstract

A patient transport apparatus includes a support structure including a base, a litter, and a lift assembly for adjusting the pose of the litter relative to the base. The apparatus also includes a battery, a primary user input device, and a controller configured to operate the lift assembly between a suspended mode and an operating mode to drive the lift assembly when a charge state of the battery is above a predetermined charge threshold. The apparatus also includes a backup system for operating the lift assembly in the suspended mode. The apparatus also includes a sensing system including at least one sensor for providing signals representative of the pose of the litter to the backup system. Based on the pose of the litter, the backup system is configured to operate the lift assembly to prevent collisions of the litter with floor surfaces during operation in the suspended mode.

Description

PATIENT TRANSPORT APPARATUS HAVING COLLISION AVOIDANCE BACKUP POWER SYSTEM CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to United States Provisional Patent Application No. 63 / 625,516 filed January 26, 2024, and to United States Provisional Patent Application No. 63 / 551,672 filed February 9, 2024, the disclosures of which are each incorporated herein by reference in their entirety.BACKGROUND

[0002] Patient transport apparatuses, such as hospital beds, stretchers, cots, tables, wheelchairs, chairs, and the like arc used to help caregivers facilitate care of patients in a health care setting. Conventional patient transport apparatuses generally include a base, an intermediate frame, and a patient support deck operatively attached to the intermediate frame. Certain patient transport apparatuses may also include one or more powered devices, such as a powered lift assembly with one or more actuators for lifting and lowering the intermediate frame relative to the base.

[0003] Power for driving powered devices such as actuators may be provided via an extension cord or tether plugged into a wall outlet. Additionally, some patient transport apparatuses include an on-board battery to supply power to actuators and other powered devices when the cord / tether is not plugged into a wall outlet.

[0004] While conventional patient transport apparatuses have generally performed well for their intended purpose, there remains a need in the art for a patient transport apparatus that affords opportunities for enhanced usability in a number of different operating conditions.SUMMARY

[0005] One general aspect of the present disclosure includes a patient transport apparatus for supporting a patient. The patient transport apparatus includes a support structure defining a head end and a foot end. The support structure includes a base, a litter operatively attached to the base and including an intermediate frame having a patient support deck, and a lift assembly arranged between the base and the inteimediate frame and configured to adjust the pose of the litter relative to the base. The lift assembly includes a foot end actuator configured to raise and lower the intermediate frame relative to the base adjacent to the foot end, and a head end actuator arranged to raise and lower the intermediate frame relative to the base adjacent to the head end. The patient transport apparatus also includes a battery for providing power to the patient transport apparatus, a primary user input device coupled to the support structure and arranged for user engagement to operate the lift assembly, and a patient transport apparatus controller disposed in electrical communication with the lift assembly, the battery, and the primary user input device. The patient transport apparatus controller is configured to operate the lift assembly between a suspended mode and an operating mode. In the operating mode, the patient transport apparatus controller is configured to drive the lift assembly with power from the battery in response to user engagement with the primary user input device when a charge state of the battery is above a predetermined charge threshold. The patient transport apparatus also includes a backup system for operating the lift assembly during operation of the patient transport apparatus in the suspended mode. The backup system includes a backup user input device coupled to the support structure and in electrical communication with the battery and the lift assembly. The backup user input device is arranged for user engagement to operate the lift assembly when the patient transport apparatus controller is in the suspended mode. The patient transport apparatus also includes asensing system in communication with the backup system. The sensing system includes at least one sensor configured to provide signals representative of the pose of the litter to the backup system. Based on the signals representative of the pose of the litter, the backup system is configured to operate the lift assembly to prevent collisions of the litter with floor surfaces during operation of the lift assembly in the suspended mode.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Advantages of the present disclosure will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.

[0007] Figure 1 is a schematic side view of a patient transport apparatus having a base, an intermediate frame supporting a patient transport surface, a lift assembly, and a backup system for providing power to the lift assembly, with the lift assembly being in a raised position.

[0008] Figure 2A is a schematic side view of the patient transport apparatus of Figure 1, with the lift assembly being in a lowered position, and shown having a fowler section arranged in a first section position.

[0009] Figure 2B is a schematic side view of the patient transport apparatus of Figure 1 , with the lift assembly being in a lowered position, and shown having a fowler section arranged a second section position.

[0010] Figure 3 is a schematic side view of the patient transport apparatus of Figure 1, with a head end actuator of the lift assembly being in a raised position and a foot end actuator of the lift assembly being in a lowered position.

[0011] Figure 4 is a schematic side view of the patient transport apparatus of Figure 1 , with a head end actuator of the lift assembly being in a lowered position and a foot end actuator of the lift assembly being in a raised position.

[0012] Figure 5 is a schematic representation of a first configuration of a primary input control.

[0013] Figure 6 is a schematic representation of a second configuration of a primary input control.

[0014] Figure 7 is a schematic representation of a first configuration of a patient transport system including a patient transport apparatus and a backup system.

[0015] Figure 8 is a schematic representation of a second configuration of a patient transport system including a patient transport apparatus and a backup system.

[0016] Figure 9 is a schematic representation of a third configuration of a patient transport system including a patient transport apparatus and a backup system.

[0017] Figures 10A and 10B are schematic representations of a fourth configuration of a patient transport system including a patient transport apparatus and a backup system.

[0018] Figures 11 A and 1 IB illustrate one configuration for operatively attaching a backup user input and a backup battery to a patient transport apparatus .

[0019] Figures 12A and 13A illustrate one configuration of operating a backup system including a first backup input control and a second backup input control.

[0020] Figure 12B and I 3B are a schematic representation of a lift assembly of a patient transport apparatus moving an intermediate frame relative to a base in response to simultaneous actuation of the first backup input control and the second backup input control of Figures 12A and

[0021] Figure 14 is a schematic representations of a fifth configuration of a patient transport system including a patient transport apparatus and a backup system.

[0022] Figure 15A is a schematic side view of the patient transport apparatus of Figure 1, shown with the lift assembly arranged in a Trendelenburg configuration with a head end actuator of the lift assembly being in a first lowered head position and a foot end actuator of the lift assembly being raised higher than the head end actuator.

[0023] Figure 15B is another schematic side view of the patient transport apparatus of Figure 15A, shown with the lift assembly arranged in a flat configuration with the head end actuator having maintained the first lowered head position and with the foot end actuator having been brought into a first lowered foot position.

[0024] Figure 15C is another schematic side view of the patient transport apparatus of Figure 15B, shown with the lift assembly arranged in the flat configuration and with the head end actuator having been brought into a second lowered head position and with the foot end actuator having been brought into a second lowered foot position.

[0025] Figure 15D is another schematic side view of the patient transport apparatus of Figure 15C, shown with the lift assembly arranged in the flat configuration and with the head end actuator having been brought into a maximum lowered head position and with the foot end actuator having been brought into a maximum lowered foot position.

[0026] Figure 15E is another schematic side view of the patient transport apparatus of Figure 15D, shown with the lift assembly arranged in the flat configuration and with the head end actuator having been brought into a maximum raised head position and with the foot end actuator having been brought into a maximum raised foot position.

[0027] Figure 16A is a diagrammatic representation of the lift assembly of Figures 15A- 15D, shown with the head end actuator arranged at a head reference position and with the foot end actuator arranged above a foot reference position.

[0028] Figure 16B is another diagrammatic representation of the lift assembly of Figure 16A, shown with the head end actuator having maintained the head reference position and with the foot end actuator having been brought to the foot reference position.

[0029] Figure 16C is another diagrammatic representation of the lift assembly of Figure 16B, shown with the head end actuator having been lowered below the head reference position and with the foot end actuator having been lowered below the foot reference position.

[0030] Figure 17A is another diagrammatic representation of the lift assembly of Figure 16A, shown with the head end actuator arranged at a second head reference position above the head reference position and with the foot end actuator arranged above a second foot reference position.

[0031] Figure 17B is another diagrammatic representation of the lift assembly of Figure 17A, shown with the head end actuator having maintained the second head reference position and with the foot end actuator having been lowered to the second foot reference position.

[0032] Figure 17C is another diagrammatic representation of the lift assembly of Figure 17B, shown with the head end actuator having been lowered below the second head reference position and with the foot end actuator having been lowered below the second foot reference position.

[0033] Figure 18A is another diagrammatic representation of the lift assembly of Figure16A, shown with the head end actuator arranged above the head reference position and with thefoot end actuator arranged above the foot reference position and also above the head reference position.

[0034] Figure 18B is another diagrammatic representation of the lift assembly of Figure 18 A, shown with the head end actuator having been lowered to the head reference position and with the foot end actuator having been lowered but still arranged above the foot reference position.

[0035] Figure 18C is another diagrammatic representation of the lift assembly of Figure 18B, shown with the head end actuator having maintained the head reference position and with the foot end actuator having been lowered to the foot reference position.

[0036] Figure 18D is another diagrammatic representation of the lift assembly of Figure 18C, shown with the head end actuator having been lowered below the head reference position and with the foot end actuator having been lowered below the foot reference position.

[0037] Figure 19A is another diagrammatic representation of the lift assembly of Figure 16 A, shown with the head end actuator arranged below the head reference position and with the foot end actuator arranged above the foot reference position and also above the head reference position.

[0038] Figure 19B is another diagrammatic representation of the lift assembly of Figure 19 A, shown with the head end actuator having maintained its arrangement below the head reference position and with the foot end actuator having been lowered to the foot reference position.

[0039] Figure 19C is another diagrammatic representation of the lift assembly of Figure 19B, shown with the head end actuator having been lowered below the head reference position and with the foot end actuator having been lowered below the foot reference position.

[0040] Figure 20A is another diagrammatic representation of the lift assembly of Figure 16 A, shown with the head end actuator arranged above the head reference position and with the foot end actuator arranged above the foot reference position and lower than the position of the head end actuator.

[0041] Figure 20B is another diagrammatic representation of the lift assembly of Figure 20A, shown with the head end actuator having maintained its arrangement above the head reference position and with the foot end actuator having been lowered into an arrangement level with the position of the head end actuator.

[0042] Figure 20C is another diagrammatic representation of the lift assembly of Figure 20B, shown with the head end actuator having been lowered below the head reference position and with the foot end actuator having been lowered below the foot reference position.

[0043] Figure 21A is another diagrammatic representation of the lift assembly of Figure 16 A, shown with the head end actuator arranged below the head reference position and with the foot end actuator arranged along the foot reference position.

[0044] Figure 2 IB is another diagrammatic representation of the lift assembly of Figure 21A, shown with the head end actuator having been raised to the head reference position and with the foot end actuator having maintained its arrangement along the foot reference position.

[0045] Figure 21C is another diagrammatic representation of the lift assembly of Figure 2 IB, shown with the head end actuator having been lowered below the head reference position and with the foot end actuator having been lowered below the foot reference position.

[0046] Figure 22A is another diagrammatic representation of the lift assembly of Figure16A, shown with the head end actuator arranged below the head reference position and with thefoot end actuator arranged below the foot reference position and higher than the position of the head end actuator.

[0047] Figure 22B is another diagrammatic representation of the lift assembly of Figure 22A, shown with the foot end actuator having been raised to the foot reference position and with the head end actuator having been raised but still arranged below the head reference position.

[0048] Figure 22C is another diagrammatic representation of the lift assembly of Figure 22B, shown with the head end actuator having been raised to the head reference position and with the foot end actuator having maintained its arrangement at the foot reference position.

[0049] Figure 22D is another diagrammatic representation of the lift assembly of Figure 22C, shown with the head end actuator having been lowered below the head reference position and with the foot end actuator having been lowered below the foot reference position.

[0050] Figure 23A is another diagrammatic representation of the lift assembly of Figure 16 A, shown with the head end actuator arranged below the head reference position and with the foot end actuator arranged below the foot reference position and higher than the position of the head end actuator.

[0051] Figure 23B is another diagrammatic representation of the lift assembly of Figure 23A, shown with the foot end actuator having maintained its arrangement below the foot reference position and with the head end actuator having been raised into an arrangement level with the position of the foot end actuator.

[0052] Figure 23C is another diagrammatic representation of the lift assembly of Figure 23B, shown with the head end actuator having been lowered below the head reference position and with the foot end actuator having been lowered below the foot reference position.

[0053] Figure 24A is another diagrammatic representation of the lift assembly of Figure 16 A, shown with the head end actuator arranged below the head reference position and with the foot end actuator arranged below the foot reference position and higher than the position of the head end actuator.

[0054] Figure 24B is another diagrammatic representation of the lift assembly of Figure 24A, shown with the head end actuator having been raised to the head reference position and with the foot end actuator having maintained its arrangement below the foot reference position.

[0055] Figure 24C is another diagrammatic representation of the lift assembly of Figure 24B, shown with the head end actuator having maintained its arrangement along the head reference position and with the foot end actuator having been raised to the foot reference position.

[0056] Figure 24D is another diagrammatic representation of the lift assembly of Figure 24C, shown with the head end actuator having been lowered below the head reference position and with the foot end actuator having been lowered below the foot reference position.

[0057] Figure 25A is another diagrammatic representation of the lift assembly of Figure 16 A, shown with the head end actuator arranged below the head reference position and with the foot end actuator arranged below the foot reference position and higher than the position of the head end actuator.

[0058] Figure 25B is another diagrammatic representation of the lift assembly of Figure 25 A, shown with the foot end actuator having maintained its arrangement below the foot reference position and with the head end actuator having been raised into an arrangement level with the position of the foot end actuator.

[0059] Figure 25C is another diagrammatic representation of the lift assembly of Figure 25B, shown with the head end actuator having been raised to the head reference position and with the foot end actuator having been raised to the foot reference position.

[0060] Figure 25D is another diagrammatic representation of the lift assembly of Figure 25C, shown with the head end actuator having been lowered below the head reference position and with the foot end actuator having been lowered below the foot reference position.DETAILED DESCRIPTION

[0061] Referring to Figures 1-4, a schematic representation of an exemplary patient transport apparatus 100 is shown for supporting a patient in a health care setting. The patient transport apparatus 100 illustrated in Figure 1 comprises a stretcher. In other versions, however, the patient transport apparatus 100 may comprise a hospital bed, cot, table, wheelchair, or similar apparatus utilized in the care of a patient.

[0062] A support structure 102 provides support for the patient. The support structure 102 illustrated in Figure 1 comprises a base 104 movable about a floor surface F, and a litter 105 operatively attached to the base 104 and including an intermediate frame 106 having a patient support deck 108. The base 104 may comprise a base frame 110. The intermediate frame 106 and the patient support deck 108 are spaced above the base 104 in Figures 1-4. The patient support deck 108 provides a patient support surface 112 upon which the patient is supported.

[0063] A mattress 113 may be disposed on the patient support deck 108 during use. The mattress 113 comprises a secondary patient support surface upon which the patient is supported. The base 104, litter 105, intermediate frame 106, patient support deck 108, and patient support surfaces 112 each have a head-end 114 and a foot-end 116 corresponding to designated placement of the patient’s head and feet on the patient transport apparatus 100. The construction of thesupport structure 102 may take on any suitable design and is not limited to that specifically set forth above. In addition, the mattress 113 may be omitted in certain versions, such that the patient rests directly on the patient support surface 112.

[0064] As will be discussed in greater detail below, the patient support deck 108 may include at least one deck section 118 arranged for movement relative to the intermediate frame 106 to support the patient in different positions, orientations, and the like. The deck sections 118 of the patient support deck 108 provide the patient support surface 112 upon which the patient is supported. More specifically, in the representative version of the patient transport apparatus 100 illustrated in Figures 1-4, the patient support deck 108 has four deck sections 118, which cooperate to define the patient support surface 112: a fowler section 120 (or back section), a seat section 122, a leg section 124, and a foot section 126. Here, the seat section 122 is fixed to the intermediate frame 106 and is not arranged for movement relative thereto. However, it will be appreciated that the seat section 122 could be movable relative to other deck sections 118 in some versions. Conversely, the fowler section 120 and the leg section 124 are arranged for movement relative to each other and to the intermediate frame 106, as described in greater detail below, and the foot section 126 is arranged to move partially concurrently with the leg section 124. Other configurations and arrangements are contemplated.

[0065] Side rails may be coupled to the intermediate frame 106 and are thereby supported by the base 104. A first side rail 128 may be positioned at a right head end of the intermediate frame 106. A second side rail 130 may be positioned at a right foot end of the intermediate frame 106. A third side rail (not shown) may be positioned at a left head end of the intermediate frame 106. A fourth side rail (not shown) may be positioned at a left foot end of the intermediate frame 106. Where the patient transport apparatus 100 is a stretcher or a cot, there may be fewer siderails. The side rails are movable to a raised position in which they block ingress and egress into and out of the patient transport apparatus 100, one or more intermediate positions, and a lowered position in which they are not an obstacle to such ingress and egress. In still other configurations, the patient transport apparatus 100 may not include any side rails. The Applicant has described versions of patient transport apparatuses having side rails equipped with actuators for “motorized” movement in United States Patent Application Publication No. US 2017 / 0172829 Al, the disclosure of which is hereby incorporated by reference in its entirety. Other configurations are contemplated. The side rails could be of any suitable type, arrangement, or configuration sufficient to selectively limit patient ingress / egress from the patient transport apparatus 100. Similarly, it will be appreciated that side rails may be attached to any suitable component or structure of the patient transport apparatus 100. Furthermore, in certain versions the side rails are coupled to one of the deck sections 118 for concurrent movement.

[0066] A headboard 136 and a footboard 138 may be coupled to the intermediate frame 106. In other versions, when the headboard 136 and footboard 138 are included, the headboard 136 and footboard 138 may be coupled to other locations on the patient transport apparatus 100, such as the base 104. In still other versions, the patient transport apparatus 100 may not include the headboard 136 and / or the footboard 138.

[0067] One or more grips (i.e., “handles”; not shown) may be integrated into the side rails, the headboard 136, and the footboard 138. In some versions, grips formed in the side rails are arranged to help facilitate patient egress from the patient transport apparatus 100. It will be appreciated that the grips formed in the side rails, as well as grips formed in the headboard 136 and / or the footboard 138, can also be used by a caregiver to facilitate movement of the patient transport apparatus 100 over floor surfaces. Additional grips may be integrated into othercomponents of the patient transport apparatus 100, such as the intermediate frame 106. The grips are shaped so as to be grasped by the patient or the caregiver. It will be appreciated that the grips could be integrated with or operatively attached to any suitable portion of the patient transport apparatus 100 or may be omitted from certain parts of the patient transport apparatus 100 in certain versions.

[0068] In addition to the headboard 136 the patient transport apparatus may further comprise user input handles (not shown). The user input handles are operable by the caregiver to control various functions of the patient transport apparatus such as powered drive wheels, steering, braking, and the like. The user input handles may further comprise buttons for selecting between different operation modes or other user configurable options that change operating parameters of the patient transport apparatus 100.

[0069] Wheels 142 are coupled to the base 104 to facilitate transportation over floor surfaces F. The wheels 142 are arranged in each of four quadrants of the base 104 adjacent to comers of the base 104. In the version shown in Figures 1-4, the wheels 142 are caster wheels able to rotate and swivel relative to the support structure 102 during transport. Here, each of the wheels 142 forms part of a caster assembly 144 that is mounted to the base 104. It should be understood that various configurations of the caster assemblies 144 are contemplated. In addition, in some versions, the wheels 142 are not caster wheels and may be non-steerable, steerable, nonpowered, powered, or combinations thereof. Additional wheels are also contemplated. For example, the patient transport apparatus 100 may comprise four non-powered, non-steerable wheels, along with one or more powered wheels. In some cases, the patient transport apparatus 100 may not include any wheels. In other versions, one or more auxiliary wheels (powered or non-powered), which are optionally movable between stowed positions and deployed positions,may be coupled to the support structure 102. In some cases, when auxiliary wheels are located between caster assemblies 144 and contact the floor surface in the deployed position, they cause two of the caster assemblies 144 to be lifted off the floor surface, thereby shortening a wheelbase of the patient transport apparatus 100. A fifth wheel may also be arranged substantially in a center of the base 104. roo7oi The patient transport apparatus 100 further comprises a lift assembly 146, generally indicated at 146, which operates to adjust the pose of the litter 105 relative to the base 104. Stated differently, the lift assembly 146 may operate to raise and lower the intermediate frame 106 relative to the base 104 which, in turn, moves the patient support deck 108 relative to the base 104 between a plurality of lift configurations, including a lowered lift configuration where the patient support deck 108 is positioned adjacent to the base 104, a raised lift configuration where the patient support deck 108 is elevated vertically above the base 104, or any desired vertical position therebetween. To this end, the lift assembly 146 may comprise one or more powered actuators 148 (i.e., electric actuator 148), such as a head end lift actuator 150 and a foot end lift actuator 152, which are each operatively attached between the intermediate frame 106 and the base 104 and arranged to facilitate movement of the patient support surface 112 with respect to the base 104. For example, the head end actuator 150 may be arranged to raise and lower the intermediate frame 106 relative to the base 104 adjacent to the head end 114, and the foot end actuator 152 may be arranged to raise and lower the intermediate frame 106 relative to the base 104 adjacent to the foot end 116.

[0071] The head end and foot end actuators 150,152 may be realized as linear actuators, rotary actuators, or other types of actuators, and are electrically powered and operated. It is contemplated that, in some versions, different arrangements of actuators may be employed, such as with rotary actuators coupled to the base 104 and to the intermediate frame 106 with a linkageextending therebetween. Furthermore, in some versions, one or more of the actuators 148 may be realized as linear actuators, rotary actuators, or other configurations of actuators configured to generate force, torque, and the like, such as via one or more electric motors, which may be coupled to geartrains, linkages, and the like to effect movement of various components of the patient transport apparatus 100, and / or which may be coupled to pumps (e.g., a hydraulic pump) disposed in fluid communication with fluid-driven actuators (e.g., hydraulic linear or rotational actuators). Other configurations are contemplated. The construction of the lift assembly 146, the head-end actuator 150, and / or the foot-end actuator 152 may take on any known or conventional design and is not limited to that specifically illustrated. By way of non-limiting example, the lift assembly 146 could be arranged with the head-end and foot-end actuators 150, 152 between the base 104 and the intermediate frame 106 in a column configuration to facilitate vertical movement of the patient support deck 108. Each of the one or more actuators 148 is operable in a first direction to raise the intermediate frame 106 relative to the base 104, and in a second direction to lower the intermediate frame 106 relative to the base 104.

[0072] As noted above, the patient support deck 108 is operatively attached to the intermediate frame 106, and one or more of the deck sections 118 may be arranged for movement between a first section position 118A (see Figure 2A) and a second section position 118B (see Figure 2B), and one or more intermediate section positions therebetween. To this end, one or more powered actuators 148 realized as deck actuators 154 may be interposed between the deck section 118 and the intermediate frame 106 to move the deck section 118 between the first section position 118A (see Figure 2A), the second section position 118B (see Figure 2B), and any other suitable section position. In the representative version illustrated herein, the deck actuator 154 is realized as a linear actuator disposed in force-translating relationship between the deck section 118 and theintermediate frame 106. More specifically, one deck actuator 154 is provided between the intermediate frame 106 and the fowler section 120, and another deck actuator 154 is provided between the intermediate frame 106 and the leg section 124, and each of the deck actuators 154 is arranged for independent movement to position the respective deck sections 118 to adjust the shape of the patient support surface 112 between a plurality of patient support configurations (for example, a flat configuration, a raised fowler configuration, a seated configuration, etc.).

[0073] Those having ordinary skill in the art will appreciate that the patient transport apparatus 100 could employ any suitable number of deck actuators 154, of any suitable type or configuration sufficient to effect selective movement of the deck section 118 relative to the support structure 102. By way of non-limiting example, the deck actuator 154 could be realized with one or more linear- actuators and / or one or more rotary actuators controlled or driven in any suitable way. Moreover, the deck actuator 154 could be mounted, secured, coupled, or otherwise operatively attached to the intermediate frame 106 and to the deck section 118, either directly or indirectly, in any suitable way. In addition, one or more of the deck actuators 154 could be omitted for certain applications.

[0074] Each of the one or more actuators 148 includes an actuator input 190 (also referred to as lift assembly input 190 in subsequent descriptions of the lift assembly 156 below) defined to receive power to operate the one or more actuators 148. For example, the head end actuator 150 may define a head end actuator input 212A for receiving power to operate the head end actuator 150. Similarly, the foot end actuator 152 may define a foot end actuator input 212B for receiving power to operate the foot end actuator 152. While the deck actuators 154 or other actuators 148 likewise include respective inputs for receiving power, subsequent description of the arrangementfor providing power to the one or more actuators 148 will be made with reference to the head end actuator 150 and the foot end actuator 152 for illustrative purposes.

[0075] As mentioned above, the patient transport apparatus 100 may comprise powered drive wheels in addition to a powered lift assembly 146. In some implementations of the patient transport apparatus 100, these systems of the patient transport apparatus 100 may be electrically powered and controlled using energy stored in a battery 160 (in some configurations, referred to as a “primary battery”). The battery 160 may be supported on, or in, the base 104, the intermediate frame 106, or other suitable locations about the patient transport apparatus 100, and is electrically coupled to the powered drive wheels, powered lift actuators, and a patient transport apparatus controller 158 to provide these and other components with electrical power. The battery 160 may include one or more cells (not shown) disposed in a battery housing, and one or more battery outputs 162 in communication with the cells and supported by the battery housing for engaging corresponding inputs on the patient transport apparatus 100, as will be discussed in further detail below. It will be appreciated that the representative versions of the battery 160 depicted throughout the drawings are shown schematically for illustrative purposes, and that various configurations, types, and arrangements of batteries 160 are contemplated by the present disclosure.

[0076] The battery 160 may comprise one cell or a plurality of cells electrically coupled to one another in order to increase storage capacity or voltage of the battery 160. The battery 160 may utilize cells having a variety of compositions. For example, the cells may be Lithium-ion type, however other types of battery such Nickel-Cadmium, Nickel-metal hydride, or Lithium polymer are also contemplated. To this end, the battery 160 may be configured to provide a suitable voltage to the battery output(s) 162 by way of different arrangement of the cells (e.g. series, parallel, series-parallel, etc.). For example, the battery 160 may provide 3.7V, 5V, 6V,12V, 18V, 36V, 40V, 60V, etc., and combinations thereof. The battery 160 may further be configured for recharging by way of a charging assembly (not shown) connected to a mains power supply or another external battery pack (not shown). The battery 160 may comprise an electrical port (not shown) in addition to the battery output that allows the battery 160 to receive power from the charging assembly. While the port may assume various configurations, in one exemplary version, the electrical port comprises a USB port. In another version, the battery 160 may be configured to be wirelessly recharged via an inductive charging circuit.

[0077] In some versions, the battery 160 may be configured to be removed from and attached to the patient transport apparatus 100 by a caregiver in order to facilitate untethered (e.g., disconnected from mains power) operation of the patient transport apparatus 100. During operation, a discharged battery 160 may be removed by a caregiver and replaced with a charged battery 160. Said differently, because a discharged battery 160 can quickly and easily be replaced with a charged battery 160, lower capacity and smaller volume batteries may be utilized without negatively impacting the usability of the patient transport apparatus 100. However, in other versions the battery 160 may not be configured to be removed from the patient transport apparatus 100. Similarly, in versions which employ multiple batteries 160, one or more batteries 160 may be not configured to be removed from the patient transport apparatus 100, while other batteries 160 may be configured and arranged for replacement by a caregiver.

[0078] The patient transport apparatus 100 further includes a primary user input device 164. The primary user input device 164 may be coupled to or otherwise arranged at any suitable location on the support structure 102. For example, in some configurations, the primary user input device 164 is coupled to the intermediate frame 106 for concurrent movement with the intermediate frame 106 relative to the base 104. The primary user input device 164 may be coupleddirectly to the intermediate frame 106, or may be indirectly coupled to the intermediate frame 106, such as to the footboard 138 and / or to one of the side rails 130 which move concurrently with the intermediate frame 106. Figures 1-4 employ phantom lines to illustrate various exemplary and non-limiting locations for coupling the primary user input device 164 to the support structure 102, including coupling the primary user input device 164 to the intermediate frame 106, the headboard 136, the footboard 138, and / or the side rails 130. Other locations for coupling the primary user input device 164 to the support structure 102 are contemplated such as, but not limited to, the base 104.

[0079] The primary user input device 164 is arranged for user engagement to operate the various functions of the patient transport apparatus 100 such as, but not limited to, operating the lift assembly 146, adjusting the deck actuators 154 or other powered devices, and the like. Other potential functions of the patient transport apparatus 100 that the primary user input device 164 may be configured to operate include, but are not limited to, various alarm / indicator systems of the patient transport apparatus 100, various lighting systems associated with the patient transport apparatus 100, various climate control systems associated with the patient transport apparatus 100, and / or various patient therapy or treatment systems associated with the patient transport apparatus 100. Other configurations are contemplated.

[0080] The primary user input device 164 includes one or more primary input controls 166 arranged for user engagement to operate functions of the patient transport apparatus 100 such as, but not limited to, operating the lift assembly 146. For example, Figure 5 shows one exemplary configuration of a portion of the primary user input device 164 including the one or more input controls 166 for operating the lift assembly 146. It will be appreciated that the primary user input device 164 could include a number of different other input controls for operating other powereddevices (not shown). In the illustrated configuration, the primary user input device 164 includes a first primary input control 166 A and a second primary input control 166B. The primary input controls 166 may be realized as elements arranged for user engagement (e.g., a touch screen or other graphic user interface, or as physical controls such as buttons, levers, switches, etc.) to operate various functionalities of the patient transport apparatus 100. roo8ii As will be discussed in further detail below, the primary input controls 166 are in electrical communication with the patient transport apparatus controller 158 to provide input signals to the patient transport apparatus controller 158 to effectuate the operation of the various functionalities of the patient transport apparatus 100. For example, in the configuration shown in Figure 5, the first primary input control 166 A is in communication with the patient transport apparatus controller 158 to provide an input signal to the patient transport apparatus controller 158. In response to receiving the input signal from the first primary input control 166A, the patient transport apparatus controller 158 is configured to provide power from the battery 160 to the lift assembly 146 (particularly, the one or more actuators 148) to raise the intermediate frame 106 relative to the base 104. Similarly, the second primary input control 166B is in communication with the patient transport apparatus controller 158 to provide an input signal to the patient transport apparatus controller 158. In response to receiving the input signal from the second primary input control 166B, the patient transport apparatus controller 158 is configured to provide power from the battery 160 to the lift assembly 146 (particularly, the head end actuator 150 and the foot end actuator 152) to adjust the intermediate frame 106 relative to the base 104.

[0082] It should be appreciated that the primary user input device 164 can include any number of primary input controls 166 for operating the lift assembly 146. For example, Figure 6 shows another configuration of the primary user input device 164. In this configuration, theprimary user input device 164 includes four primary input controls 166 to allow the head end actuator 150 and the foot end actuator 152 to be operated independently, as illustrated by Figures 3 and 4, such as to place the patient support deck 108 in a Trendelenburg configuration CT or reverse Trendelenburg configuration CV. Other configurations of the primary user input device may be realized with any suitable number of primary input controls 166 to provide input signals to the patient transport apparatus controller 158 to operate the various functionalities of the patient transport apparatus 100.

[0083] In some versions, the patient transport apparatus 100 and a backup system 200 (discussed in further detail below) define a patient transport system 98 for operating the lift assembly 146 or other powered devices of the patient transport apparatus 100 when a state of charge of the battery 160 is below a predetermined threshold. Referring to Figures 7-10B, which show schematic representations of a number of configurations of a patient transport system 98 of the present disclosure, the patient transport apparatus controller 158 is disposed in electrical communication with the lift assembly 146, the primary battery 160, and the primary user input device 164. While the patient transport apparatus controller 158 may be in electrical communication with additional subsystems of the patient transport apparatus 100, additional subsystems have been omitted from Figures 7-10B for illustrative purposes to schematically depict the interconnection of the patient transport apparatus 100 and the backup system 200.

[0084] Referring to Figures 7-10B, the battery output 162 of the battery 160 is in electrical communication with a controller power input 168 of the patient transport apparatus controller 158 and a primary user input device power input 170 of the primary user input device 164 across a primary power input circuit 172 to provide power from the battery 160 to the primary user input device 164 and the patient transport apparatus controller 158. However, other circuitconfigurations for providing power from the battery 160 to the patient transport apparatus controller 158 and the primary user input device 164 are contemplated.

[0085] With continued reference to Figures 7-10B, the patient transport apparatus controller 158 may include a motion control circuit 174 for operating the lift assembly 146 that is interposed between the battery 160 and the lift assembly 146. The motion control circuit 174 includes a motion control unit 176. The motion control unit 176 may be configured to receive input signals from the primary user input device 164 over a communication circuit COMM. Based on the input signals generated from user engagement with the primary user input device 164 and provided to the motion control unit 176, the motion control unit 176 is configured to provide power to the lift assembly 146 to operate the lift assembly 146. The motion control unit 176 includes a motion control unit input 178 and a motion control unit output 180. The motion control unit input 178 is in electrical communication with the controller power input 168 such that the battery 160 provides power to the motion control unit 176. The motion control circuit 174 also includes a motor bridge 182 for controlling power received from the motion control unit output 180 to move the lift assembly 146 in a desired direction. More particularly, the motor bridge 182 includes a motor bridge input 184 and a motor bridge output 186. The motor bridge input 184 is in electrical communication with the motion control unit output 180 to receive the power from the battery 160 to operate the lift assembly 146. The motor bridge output 186 is in communication with a lift assembly output 188 defined by the motion control circuit 174 of the patient transport apparatus controller 158 to provide power to the lift assembly 146. More particularly, the lift assembly output 188 is in communication with a lift assembly input 190 defined by the lift assembly 146 to provide power to the one or more actuators 148 to operate the one or more actuators 148.

[0086] The patient transport apparatus controller 158 may be operable between an operating mode and a suspended mode. In the operating mode, the patient transport apparatus controller 158 is configured to drive the lift assembly 146 with power from the battery 160 in response to user engagement with the primary user input device 164 when a charge state of the battery 160 is above a predetermined charge threshold. Additionally, in the operating mode, the patient transport apparatus controller 158 may be configured to operate other functionalities of the patient transport apparatus 100. In the suspended mode, when the state of charge of the battery 160 is below the predetermined threshold, the patient transport apparatus controller 158 is inhibited from driving the lift assembly 146 with power from the battery 160 in response to user engagement with the primary user input device 164. Additionally, in the suspended mode, the patient transport apparatus controller 158 may be configured to inhibit operation of other functionalities of the patient transport apparatus 100. In some configurations, the predetermined threshold may be any state of charge level where it is no longer suitable to operate the functionalities of the patient transport apparatus 100, such as 0% or less than 5% state of charge. In other configurations, the predetermined threshold may be a state of charge level sufficient to provide reserve power to the functionalities of the patient transport apparatus 100, such as the lift assembly 146, for emergency situations. The state of charge level sufficient to provide reserve power may be a certain percentage of state of charge, such as, but not limited to, 10%, 15%, or 20%, or defined as a state of charge to permit a predetermined number of articulations of the one or more actuators 148 reserved for emergency situations. In the suspended mode, the backup system 200 (described in further detail below) is used for operating the lift assembly 146 during operation of the patient transport apparatus controller 158 in the suspended mode, instead of operating the lift assembly146 using the primary user input device 164, as in the operating mode.

[0087] In some configurations, such as shown in Figures 7 and 8, the backup system 200 includes at least one backup battery 202, separate from the primary battery 160, for providing power to the lift assembly 146 during operation of the patient transport apparatus controller 158 in the suspended mode. As will be appreciated from the subsequent description below, “primary” and “backup” are non-limiting terms utilized herein to differentiate between two batteries 160, 202, and other terms (e.g., “first” and “second”) could be used in place of the terms “primary” and “backup” in some versions. The backup system 200 shown in Figures 7 and 8 includes at least one separate backup battery 202 for powering the lift assembly 146 even in the event that the state of charge of the primary battery 160 is insufficient to power articulations of the lift assembly 146 (e.g., 0% state of charge or another insufficient state of charge). The at least one backup battery 202 may be operatively attached to the support structure as described in further detail below, and is disposed in electrical communication with the lift assembly 146 for providing power to the lift assembly 146. In some versions, the backup battery 202 is configured to be charged by at least one of the primary battery 160 or an AC mains power supply (not shown). Additionally, the backup system 200 may further include an alarm configured to generate an alert when a state of charge of the backup battery 202 is below an operable threshold. Alternatively, or additionally, the backup system 200 may further include a visual indicator configured to provide visual indication when a state of charge of the backup battery 202 is below an operable threshold.

[0088] The backup system 200 shown in Figures 7 and 8 also includes at least one backup user input device 204 arranged for user engagement to operate the lift assembly 146 during operation of the patient transport apparatus controller 158 in the suspended mode. The at least one backup user input device 204 is interposed in electrical communication between the at least one backup battery 202 and the lift assembly input 190.

[0089] Figures 9 and 10A-10B show other configurations of the backup system 200 for operating the lift assembly 146 during operation of the patient transport apparatus controller 158 in the suspended mode that do not include a separate backup battery 202. Here, the backup user input device 204 is interposed in electrical communication between the battery 160 and the lift assembly input 190 for providing power to the lift assembly 146 during operation of the patient transport apparatus controller 158 in the suspended mode. Put differently, the backup system 200 shown in Figures 9 and 10A-10B is configured to power the lift assembly 146 when the state of charge of the battery 160 is below the predetermined threshold but has a state of charge level sufficient to provide reserve power to power the lift assembly 146, as described above. Like the configurations shown in Figures 7 and 8, the backup user input device 204 shown in Figures 9 and 10A-10B is arranged for user engagement to operate the lift assembly 146 during operation of the patient transport apparatus controller 158 in the suspended mode.

[0090] Referring back to Figure 7, the backup battery 202 includes a backup battery output 206. The backup user input device 204 includes a backup user input device input 208 that is in electrical communication with the backup battery output 206 to provide power to the backup user input device 204. The backup user input device 204 also includes a backup user input device output 210 that is in electrical communication with the lift assembly input 190 to provide power to operate the lift assembly 146 during operation of the patient transport apparatus controller 158 in the suspended mode.

[0091] As best shown in Figure 8, in some configurations, the lift assembly output 188 of the patient transport apparatus controller 158 may be further defined as a head end lift assembly output 188 A disposed in electrical communication with the head end actuator input 212A defined by the head end actuator 150 to provide power to the head end actuator 150, and the patienttransport apparatus controller 158 further defines a foot end lift assembly output 188B disposed in electrical communication with a foot end actuator input 212B defined by the foot end actuator 152 to provide power to the foot end actuator 152. Although not shown, similar configurations of electrical communication between the lift assembly input and the inputs of the one or more actuators 148 are contemplated for the versions shown in Figures 7, 9, and 10A-10B.F0092] In other configurations, such as shown in Figure 8, the backup system 200 may include a head end backup system 200A that includes a head end backup battery 202A and a head end backup user input device 204A to operate the head end actuator 150 using power from the head end backup battery 202A. Additionally, the backup system 200 may include a foot end backup system 200B that includes a foot end backup battery 202B and a foot end backup user input device 206B to operate the foot end actuator 152 using power from the foot end backup battery 202B.

[0093] In the configuration shown in Figure 8, the head end backup system 200A may be disposed in electrical communication with the head end actuator input 212A for operating the head end actuator 150 with power from the head end battery 202A in response to user engagement with the head end backup user input device 204A. Similar to the configuration of Figure 7, the head end backup battery 202A includes a head end backup battery output 206A. The head end backup user input device 204A includes a head end backup user input device input 208A that is in electrical communication with the head end backup battery 202A to provide power to the head end backup user input device 204A. The head end backup user input device 204 A also includes a head end backup user input device output 210A that is in electrical communication with the head end actuator input 212A to provide power to operate the head end actuator 150 during operation of the patient transport apparatus controller 158 in the suspended mode.

[0094] With continued reference to Figure 8, similarly, the foot end backup system 200B may be disposed in electrical communication with the foot end actuator input 212B for operating the foot end actuator 152 with power from the foot end battery 202B in response to user engagement with the foot end backup user input device 204B. Also similar’ to the configuration of Figure 7, the foot end backup battery 202B includes a foot end backup battery output 208B. The foot end backup user input device 204B includes a foot end backup user input device input 206B that is in electrical communication with the foot end backup battery 202B to provide power to the foot end backup user input device 204B. The foot end backup user input device 204B also includes a foot end backup user input device output 208B that is in electrical communication with the foot end actuator input 212B to provide power to operate the foot end actuator 152 during operation of the patient transport apparatus controller 158 in the suspended mode.

[0095] In some configurations, such as shown in Figures 7 and 8, the backup user input devices 204, 204A, 204B may be each configured for user-selected operation between an interrupt state and a drive state. In the configuration of Figure 7, the interrupt state is defined by interrupted electrical communication between the backup battery 202 and the lift assembly input 190, while the drive state is defined by electrical communication between the backup battery 202 and the lift assembly input 190. In the configuration of Figure 8, for the head end user input device 204A, the intemupt state is defined by interrupted electrical communication between the head end backup battery 202A and the head end actuator input 212A. Similarly, for the foot end user input device 204B, the interrupt state is defined by interrupted electrical communication between the foot end backup battery 202B and the foot end actuator input 212B. For the head end user input device 204A, the drive state is defined by electrical communication between the head end backup battery202A and head end actuator input 212A. Similarly, for the foot end user input device 204B, thedrive state is defined by electrical communication between the foot end backup battery 202B and foot end actuator input 212B. It should be appreciated that the head end user input device 204 A and the foot end user input device 204B may independently switch between the intermpt mode and the drive mode.

[0096] Similar to as discussed above, in other configurations, such as shown in Figures 9 and 10A- 10B, the backup user input device 204 may be also configured for user-selected operation between an interrupt state and a drive state. In the configurations shown in Figures 9 and 10A- 10B, the interrupt state is defined by interrupted electrical communication between the battery 160 and the lift assembly input 190. Also, in the configurations shown in Figures 9 and 10A-10B, the drive state is defined by electrical communication between the battery 160 and the lift assembly input 190.

[0097] In the drive state, the backup user input device(s) 204, 204A, 204B are configured to provide power from the backup battery / batteries 202, 202A, 202B or reserve power from the battery 160 (for the configurations shown in Figures 9-10B) to power the one or more actuators 148 of the lift assembly 146 to move the one or more actuators 148 in the first direction and / or the second direction to raise or lower the intermediate frame 106 relative to the base 104 in response to user engagement with the backup user input device 204. Accordingly, the backup user input device 204 enables the lift assembly 146 to be operated during operation of the patient transport apparatus controller 158 in the suspended mode, allowing a user to operate the lift assembly 146 in emergency situations where the functionality of the patient transport apparatus 100 would otherwise be inhibited due to the state of charge of the battery 160 being below the predetermined threshold.

[0098] In some configurations, the backup user input device 204 is configured to operate the one or more actuators 148 of the lift assembly 146 simultaneously and in one direction. For example, based on user engagement with the backup user input device 204, the backup user input device may provide power to the head end actuator 150 and the foot end actuator 152 to simultaneously move both the head end actuator 150 and the foot end actuator 152 in the same direction, such as the second direction, to lower the lift assembly 146 in an emergency situation.

[0099] In some versions, the backup user input device 204 may include one or more backup input controls 216 arranged for user engagement to operate the lift assembly 146. For example, the backup user input device may include a singular backup input control 216 arranged for user engagement to operate the lift assembly 146. Upon user engagement of the singular backup input control 216, the backup user input device 204 may be configured to engage the drive mode to operate the one or more actuators 148 of the lift assembly 146 simultaneously in the second direction to lower the intermediate frame 106 relative to the base 104. In other configurations, the backup user input device 204 includes a pair of backup input controls 216, each arranged for user engagement to operate at least the lift assembly 146. In some configurations, the pair of backup input controls 216 acts as a redundancy, and the backup user input device 204 only operates the lift assembly 146 in response to simultaneous actuation of each of the backup input controls 216. In other words, in configurations where backup input controls are arranged as pairs, two-handed operation is required to operate the backup system 200 to operate the lift assembly 146. This arrangement helps to discourage routine caregiver use of the backup user input device 204 rather than the primary user input device 164 during normal operation (e.g., with a fully charged battery160). Here too, it will be appreciated that “primary” and “backup” are non-limiting terms utilizedherein to differentiate between two user input devices 164, 204, and other terms (e.g., “first” and “second”) could be used in place of the terms “primary” and “backup” in some versions.

[0100] In other configurations, the backup user input device 204 is configured to operate the one or more actuators 148 of the lift assembly 146 in both directions (either simultaneously or independently). Accordingly, the backup user input device 204 may include a switching circuit 214 to operate the backup user input device 204 between the interrupt state and a raise drive state or a lower drive state in response to user engagement with the backup user input device 204. The switching circuit 214 may be interposed between the backup user input device input 208 and the backup user input device output 210. As will be appreciated from the subsequent description below, in some versions, the switching circuit 214 may include or otherwise be defined by a single electrical component (e.g., a switch), or by a plurality of components (e.g., one or more switches, relays, circuits, controllers, discrete electrical components, and the like).

[0101] The switching circuit 214 or another portion of the backup system 200 may include, for example, a raise switch (not shown) and a lower switch (not shown). The raise switch may be operable between a raise switch interrupt state where the battery 160 (or, in the configuration of Figures 7 and 8, the backup battery / batteries 202, 202 A, 202B) and the lift assembly input 190 are electrically decoupled, and a raise switch drive state where the battery 160 (or, in the configuration of Figures 7 and 8, the backup battery / batteries 202, 202A, 202B) and the lift assembly input 190 are electrically coupled to power the one or more actuators 148 of the lift assembly 146 to move in the first direction to raise the intermediate frame 106 relative to the base 104. The lower switch may be operable between a lower switch interrupt state where the battery 160 (or, in the configuration of Figures 7 and 8, the backup battery / batteries 202, 202A, 202B) and the lift assembly input 190 are electrically decoupled, and a lower switch drive state where the battery160 (or, in the configuration of Figures 7 and 8, the backup battery / batteries 202, 202A, 202B) and the lift assembly input 190 are electrically coupled to power the one or more actuators 148 of the lift assembly 146 to move in the second direction to lower the intermediate frame 106 relative to the base 104.

[0102] The backup user input device 204 may also include a first backup input control 216A for operating the one or more actuators 148 in a first direction to raise the intermediate frame 106 relative to the base 104, and a second backup input control 216B for operating the one or more actuators 148 in a second direction to lower the intermediate frame 106 relative to the base 104. In some configurations, the first backup input control 216A is in electrical communication with the raise switch to operate the raise switch between the raise switch interrupt state and the raise switch drive state, and the second backup input control 216B is in electrical communication with the lower switch to operate the lower switch between the lower switch interrupt state and the lower switch drive state. Additional backup input controls 216 are contemplated. For example, the backup user input device 204 may include additional backup input controls 166 arranged for user engagement to facilitate independent operation of the head end actuator 150 and the foot end actuator 152. Other configurations are contemplated.

[0103] Referring to Figures 11A-13B, in some versions, the backup user input device 204 includes a pair of first backup input controls 216A and a pair of second backup input controls 216B, each arranged for user engagement to operate at least the lift assembly 146. In the illustrated configuration, the pair of backup input controls 216A, 216B acts as a redundancy, and the backup user input device 204 only operates the lift assembly 146 in response to simultaneous actuation of each corresponding pair of backup input controls 216A, 216B. As also illustrated by Figures 11 A-11B, 12A, and 13A, in some configurations, each pair of backup input controls 216A, 216B maybe disposed in spaced relation from each other in various ways so as to inhibit single-handed operation by the caregiver.

[0104] Referring to Figure 9, in some versions, the backup user input device output 210 is in electrical communication with the lift assembly input 190 to provide power from the battery 160 to the lift assembly 146 in response to user engagement with the backup user input device 204. However, in other configurations, such as shown in Figures 10A-10B, the backup user input device may be in electrical communication with the motion control circuit 174.

[0105] Referring to Figures 10A-10B, to facilitate the connection of the backup user input device 204 to the motion control circuit 174, in some configurations, the motion control circuit 174 of the patient transport apparatus controller 158 further includes a bridge switch 218. The bridge switch 218 may be interposed between the motion control unit 176 and the motor bridge 182. More specifically, in some configurations, the bridge switch 218 is interposed between the motion control unit output 180 and the motor bridge input 184. The bridge switch 218 may be operable between an open bridge state (shown in Figure 10B) to interrupt electrical communication between the motor bridge 182 and the motion control unit 176, and a closed bridge state (shown in Figure 10A) to electrically couple the motor bridge 182 to the motion control unit 176. The patient transport apparatus controller 158 is configured to operate the bridge switch 218 in the closed bridge state in response to charge in the battery 160 being above a predetermined bridge switch threshold. In other words, when the charge in the battery 160 is below the predetermined bridge switch threshold, the patient transport apparatus controller 158 is configured to operate the bridge switch 218 in the open bridge state to electrically decouple the motion control unit 176 from the motor bridge 182 to allow the backup system 200 to power and operate the lift assembly 146.In some configurations, the switch threshold may be the same as the predetermined threshold of the state of charge of the battery 160, however, different thresholds are contemplated.

[0106] With continued reference to Figures 10A-10B, in the illustrated configuration, the patient transport apparatus controller 158 further includes a bypass input 220 disposed in electrical communication with the backup user input device 204. A bypass circuit 222 is electrically coupled between the bypass input 220 and the lift assembly output 188 of the patient transport apparatus controller 158 to provide power to the lift assembly 146 from the backup system 200 during operation of the patient transport apparatus controller 158 in the suspended mode. Accordingly, in this configuration, power from the backup system 200 bypasses the motion control unit 176. The patient transport apparatus controller 158 may also include a switch circuit 224 electrically coupled between the bridge switch 218 and the motor bridge 182 (particularly, the motor bridge input 184). The patient transport apparatus controller 158 may also further include a diode 226 interposed between the bypass circuit 222 and the switch circuit 224 to inhibit electrical communication between the bypass circuit 222 and the switch circuit 224 when the bridge switch 218 operates in the closed bridge state.

[0107] In other words, when the bridge switch2 18 operates in the closed bridge state, the motion control unit 176 provides power from the battery 160 to the motor bridge 182 based on user engagement with the primary user input device 164, and the diode acts to prevent electrical backflow from the switch circuit 224 into the bypass circuit 222. Conversely, when the bridge switch2 18 operates in the open bridge state, the bypass circuit 222 provides power from the backup system 200 to power and operate the lift assembly 146 based on user engagement with the backup user input device 204.

[0108] In some configurations, the backup battery 202 and / or the backup user input device 204 may be removable coupled to the support structure 102. In some configurations, the backup battery 202 and / or the backup user input device 204 are coupled to the base 104, but they may be couple elsewhere suitable on the support structure 102 such as, but not limited to, the intermediate frame 106. Referring back to Figures 11A-13B, the backup battery 202 may define a backup battery coupler 228 (i.e., an interface defined by the backup battery 202) for removably coupling the backup battery 202 to the support structure 102. Accordingly, the support structure 102 may define a corresponding backup battery receiver 230 shaped to receive the backup battery coupler 228 to couple the backup battery 202 physically and electrically to the patient transport system 98 (particularly, the backup system 200). Accordingly, Figure 11A shows the backup battery 202 spaced from the backup battery receiver 230, and Figure 11B should the backup battery coupler 228 engaged with the backup battery receiver 230. In some configurations, the backup battery receiver 230 may be defined by the base 104.

[0109] Similarly, in some configurations, referring back to Figures 11A-13B, the backup user input device 204 may define a backup user input device coupler 232 (i.e., an interface defined by the backup user input device 204) for removably coupling the backup user input device 204 to the support structure 102. Accordingly, the support structure 102 may defines a backup user interface receiver 234 shaped to receive the backup user input device coupler 232 to couple the backup user input device 204 physically and electrically to the patient transport system 98 (particularly, the backup system 200). Here, Figure 11 A shows the backup user input device 204 spaced from the backup user input device receiver 234, and Figure 11B shows the backup user input device coupler 232 engaged with the backup user input device receiver 234. In some configurations, the backup user input device receiver 234 may be defined by the base 104.Additionally, as illustrated in phantom in Figures 1 1 A and 1 IB, the backup user input device 204 may include a backup user input device cover 236 operatively attached to the backup user input device 204 to prevent inadvertent engagement of the backup input control(s) 216. In some configurations, the backup user input device cover 236 may be pivotably attached to the backup user input device 204 such that a user may pivot the backup user input device cover 236 to access the backup user input device 204 to operate the backup system 200. In other configurations, such as shown schematically in Figures 1-4, the backup battery and the backup user input device 204 may be one integral unit that is removable coupled to the support structure 102.

[0110] Referring now to Figures 14-25D, as noted above, the lift assembly 146 is typically arranged between the base 104 and the intermediate frame 106 and is configured to facilitate adjusting the pose (i.e., the height and / or angle) of the litter 105 relative to the base 104 between a plurality of configurations via the head end actuator 150 and the foot end actuator 152. By way of illustrative example, Figure 15 A depicts the litter 105 in a Trendelenburg configuration CT with the head end actuator 150 arranged at a lower position than the foot end actuator 152, whereas Figure 15B depicts the litter 105 in a flat configuration CF with the head end actuator 150 arranged at substantially the same height as the foot end actuator 152. As noted above, the head end actuator 150 and the foot end actuator 152 may be operated concurrently and / or independently, and may be adjusted between a plurality of respective heights so as to place the litter 105 in a plurality of different configurations, positions, and the like, including for example a maximum lowered configuration CL (see Figure 15D), a maximum raised configuration CR (see Figure 15E), and various intermediate configurations CI therebetween (see Figures 15B-15C). Other configurations are contemplated.

[0111] In some versions, the patient transport apparatus 100 may employ a sensing system 238 that is utilized in the operating mode and / or in the suspended mode to facilitate operation of the lift assembly 146 and / or other portions of the patient transport apparatus 100. Generally, the sensing system 238 is in communication with the backup system 200 (and optionally the patient transport apparatus controller 158) and includes least one sensor S configured to provide signals representative of the pose of the litter 105 to the backup system 200 and / or the patient transport apparatus controller 158. Based on the signals representative of the pose of the litter 105, the backup system 200 and / or the patient transport apparatus controller 158 is / are configured to operate the lift assembly 146 to prevent collisions of the litter 105 with floor surfaces. For example, during operation in the operation mode, the patient transport apparatus controller 158 may operate the lift assembly 146 to prevent collisions of the litter 105 with floor surfaces, and during operation in the suspended mode, backup system 200 may operate the lift assembly 146 to prevent collisions of the litter 105 with floor surfaces. More specifically, based on the signals representative of the pose of the litter 105, the backup system 200 and / or the patient transport apparatus controller 158 may be configured to coordinate operation of the head end actuator 150 and the foot end actuator 152 to prevent collisions of the litter 105 with floor surfaces.

[0112] A number of different approaches to coordinating operation of the head end actuator 150 and the foot end actuator 152 to prevent collisions of the litter 105 with floor surfaces are contemplated, with exemplary scenarios described in further detail below. Generally, coordination of operation of the head end actuator 150 and the foot end actuator 152 to prevent collisions of the litter 105 with floor surfaces may include starting operation of one of the head end actuator 150 and the foot end actuator 152 before the other of the head end actuator 150 and the foot end actuator 152, stopping operation of one of the head end actuator 150 and the foot endactuator 152 before the other of the head end actuator 150 and the foot end actuator 150, and / or operating of one of the head end actuator 150 and the foot end actuator 152 at a different speed than the other of the head end actuator 150 and the foot end actuator 152.

[0113] It will be appreciated that the backup system 200 and / or the patient transport apparatus controller 158 can be configured to facilitate operation of the lift assembly 146 in a number of different ways, including without limitation based on signals or feedback received from the sensing system 238 and / or various types of sensors S, the battery 160, the user input devices 164, 204, and the like. By way of non-limiting example, the head and foot end actuators 150, 152 may each include respective actuator position sensors SA (see Figure 14; not shown in detail) configured to generate signals indicative of the length, configuration, height, and the like of the respective actuator 150, 152 between maximum and minimum arrangements (e.g., maximum and minimum stroke length). Here, actuator position sensors SA may be realized as a part of the sensing system 238, and may generate signals that are communicated to the patient transport apparatus controller 158 (e.g., the motion control unit 176), either directly or indirectly (e.g., via one or more additional controllers, circuit, units, modules, and the like) to facilitate adjusting the configuration of the intermediate frame 106 relative to the base 104 in the operating mode as noted above. In some versions, operation of the lift assembly 146 or other portions of the patient transport apparatus 100 may be similar to as is disclosed in U.S. Patent No. 11,020,295 entitled “Patient Support Systems And Methods For Assisting Caregivers With Patient Care,” and / or U.S. Patent No. 10,945,902 entitled “Techniques For Controlling Actuators Of A Patient Support Apparatus,” the disclosures of each of which are hereby incorporated by reference in their entirety.Other configurations are contemplated.

[0114] In some versions, the sensing system 238 may include one or more load cells 240 interposed in force-translating relation between the intermediate frame 106 and the base 104 to measure load acting on the support structure 102. While not depicted in detail throughout the drawings, it will be appreciated that load cells 240 may be arranged in various ways about the support structure 102, such as for example coupled between the actuators 150, 152 and the intermediate frame 106, coupled between the actuators 150, 152 and the base 104, coupled to a weigh frame (not shown) of the support structure 102, and the like. Various types, styles, and / or quantities of load cells 240 may be utilized as a part of the sensing system 238. In some versions, each load cell 240 generates a respective output signal representing the amount of weight sensed thereby. Here, the patient transport apparatus controller 158 and / or other portions of the patient transport apparatus 100 or patient transport system 100 may monitor output signals generated by the one or more load cells 240 to measure patient weight and / or to monitor changes in patient position (e.g., as a part of a bed exit detection system, pre-exit detection system, patient monitoring system, and the like). In some versions, aspects of the patient transport apparatus 100, including the arrangement of load cells 240 about support structures 102, may be similar to as is described in International Patent Application Publication No. WO 2021 / 242946 Al entitled “Lz / t Systems And Load Cells For Patient Support Apparatus, ” International Patent Application Publication No. WO 2021 / 108377 entitled “Patient Support Apparatus With Load Cell Assemblies,'" U.S. Patent Application Publication No. US 2021 / 0030611 Al entitled “Patient Support Apparatus With Load Cell Assemblies," and / or U.S. Patent Application Publication No. US 2023 / 0346615 A l entitled “Patient Support Apparatus For Treating Patients Presenting Behavioral Health Indicia," the disclosures of each of which are hereby incorporated by reference in their entirety. Other configurations are contemplated.

[0115] Those having ordinary skill in the art will appreciate that, depending on the configuration of the base 104, the intermediate frame 106, the lift assembly 146, and / or other components of the patient transport apparatus 100, signals or feedback from the actuator position sensors SA and / or other portions of the sensing system 238 may be utilized (e.g., by the patient transport apparatus controller 158) so as to ensure proper operation of the lift assembly 146 by, among other things, controlling changes in the position, speed, or other aspects of each of the actuators 150, 152 to enable adjustment to different configurations of the intermediate frame 106 relative to the base 104. By way of illustrative example, in some versions, transitioning between different configurations of the intermediate frame 106 may be achieved by one or more of: stalling or stopping one actuator 150, 152 before the other actuator 150, 152, driving one actuator 150, 152 at a different speed than the other actuator 150, 152, increasing or otherwise ramping up (or down) the speed of one or more of the actuators 150, 152, or otherwise driving one of the actuators 150, 152 differently from the other of the actuators 150, 152. Here too, it will be appreciated that transitioning between different configurations of the intermediate frame 106 may also involve coordination of the start and / or stopping of operation of one or more actuators 150, 152 either with each other and / or with operation of other components of the patient transport apparatus 100 (e.g., deck actuators 154, other actuators 148, and the like). Those having ordinary skill in the ail will appreciate that controlling the actuators 150, 152 in these ways based on signals from the actuator position sensors SA and / or other portions of the sensing system 238 may, among other things, be utilized to preventing the actuators 150, 152 from moving the intermediate frame 106 into undesirable configurations such as those which may be unsuitable for patient support and / or which may otherwise result in collisions between various portions of the patient transport apparatus 100 and / or with ground or floor surfaces. By way of illustrative example, components of the supportstructure 102 and / or other portions of the patient transport apparatus 100 could be configured so as to be physically capable of achieving undesirable configurations in response to improper operation of the actuators 150, 152, such as by driving one actuator 150, 152 to its maximum stroke length and driving the other actuator 150, 152 to its minimum stroke length.

[0116] The sensing system 238 is utilized to prevent collisions of the type described above during operation in the suspended mode or otherwise via the versions of the backup system 200 described herein. To this end, and as is depicted schematically in Figure 14, in some versions the sensing system 238 includes a head switch 242 operatively attached to the head end actuator 150, and a foot switch 244 operatively attached to the foot end actuator 152. The switches 242, 244 are configured to determine whether the actuators 150, 152 are extended above or retracted below a respective predetermined reference position RH, RF. In these examples, based on whether the head end actuator 150 is extended above or retracted below a predetermined head end reference position RH and based on whether the foot end actuator 152 is extended above or retracted below a predetermined foot end reference position RF, the backup system 200 is configured to operate the lift assembly 146 to prevent collisions of the litter 105 with floor surfaces during operation of the lift assembly 146 in the suspended mode.

[0117] In some versions, the switches 242, 244 are formed integrally with the actuators 150, 152. In other versions, the switches 242, 244 may be mounted externally to the actuators 150, 152. In still other versions, the switches 242, 244 may not be coupled to the actuators 150, 152 and may instead be operatively attached to other portions of the patient transport apparatus 100. Moreover, and as will be appreciated from the subsequent description below, the switches 242,244 may be of various styles, types, arrangements, and / or configurations, and may instead berealized as sensors S or other portions of the sensing system 238 which are able to determine the arrangement or position of the actuators 150, 152 relative to the reference positions RH, RF.

[0118] In the representative version illustrated herein, the switches 242, 244 are in communication with or incorporated as a part of the switching circuit 214 of the backup system 200 and are configured so as to activate only during operation in the suspended mode as the battery 160 (and / or backup battery / batteries) is utilized to operate the lift assembly 146 in response to user engagement with the user input devices as described above. In these examples, the switches 242, 244 operate to coordinate operation of the head end actuator 150 and the foot end actuator 152 to prevent collisions of the litter 105 with floor surfaces during operation of the backup user input device 204 in the drive state (as described above). For example, as explored further in the scenarios described below, generally, the head switch 242 may be configured to route power from the battery 160 (and / or backup batteries) to the head end actuator 150 based on i) whether the head end actuator 150 is extended above or retracted below the predetermined head end reference position RH, and ii) whether the foot end actuator 150 is extended above or retracted below the predetermined foot end reference position RF to coordinate operation of the head end actuator 150 and the foot end actuator 152 to prevent collisions of the litter 105 with floor surfaces. Likewise, generally, the foot switch 244 may be configured to route power from the battery 160 (and / or backup batteries) to the foot end actuator 152 based on i) whether the head end actuator 150 is extended above or retracted below the predetermined head end reference position RH, and ii) whether the foot end actuator 152 is extended above or retracted below the predetermined foot end reference position RF to coordinate operation of the head end actuator 150 and the foot end actuator152 to prevent collisions of the litter 105 with floor surfaces.

[0119] Stated differently, the switches 242, 244 may be realized as “power switches” which are configured to route power from the battery 160 (and / or backup batteries) to the respective actuators 150, 152 which are raised above their reference positions RH, RF during operation of the backup system 200 to facilitate lowering the intermediate frame 106 in the suspended mode. However, as will be appreciated from the description of the scenarios illustrated by Figures 16A-20C below, the switches 242, 244 may be configured in a number of different ways sufficient to cause the backup system 200 to prevent operation of actuators 150, 152 which are at or below their reference positions RH, RF until certain conditions are met. For example, the switches 242, 244 could be formed as a part of a circuit (e.g., with one or more relays, transistors, and the like; not shown in detail) configured to facilitate routing power to both actuators 150, 152 so as to lower the intermediate frame 106 once both of the actuators 150, 152 are below their respective reference positions RH, RF. Here too, in some versions, the switches 242, 244 could be formed as a part of a circuit (e.g., with one or more relays, transistors, and the like; not shown in detail) configured to facilitate routing power to both actuators 150, 152 so as to raise the intermediate frame 106 once both of the actuators 150, 152 are above their respective reference positions RH, RF. Moreover, and as will be appreciated from the subsequent description below, the circuit could be configured so as to allow one or both actuators 150, 152 to raise up to their respective reference position RH, RF and / or to lower down to their respective reference position RH, RF, either sequentially or at least partially simultaneously, in various ways depending such as on the configuration of the user input device 164 and / or the backup user input device 204.

[0120] In some versions, the switches 242, 244 could control selectively routing power to the respective actuators 150, 152 based on their positions relative to the respective reference positions RH, RF, and the sensing system 238 could also include an angle switch 246 responsiveto changes in the angle of the intermediate frame 106 relative to the base 104 which changes operation of the switching circuit 214 so that power is directed to both actuators 150, 152 once the intermediate frame 106 achieves a predetermined angular- arrangement (e.g., into the flat configuration CF) and, in some versions, irrespective of the position of the actuators 150, 152 relative to their respective reference positions RH, RF. It will be appreciated that the head switch 242, the foot switch 244, and / or the angle switch 246 could each be configured in a number of different ways sufficient to form a part of the switching circuit 214 or another part of the backup systems 200 described herein, either by directly routing power to the actuators 150, 152, and / or by indirectly routing power to the actuators 150, 152 by controlling other components (e.g., relays), without impacting the ability to drive the actuators 150, 152 in the operating mode via the motion control unit 176.

[0121] Referring now to Figures 16A-25D, various diagrammatic representations of the lift assembly 146 are shown depicting positions of the actuators 150, 152 and the corresponding arrangement of the intermediate frame 106 in different scenarios, each of which will be described in greater detail below in connection with operation of the backup system 200. In these diagrammatic representations, a vertical line is used to represent the possible range of motion of each of the actuators 150, 152. A dashed horizontal line extending between the top of the vertical lines represents the maximum raised configuration CR (e.g., see Figure 15E), and a dashed horizontal line extending between the bottom of the vertical lines represents the maximum lowered configuration CL (e.g., see Figure 15D). The current position of the actuators 150, 152 is represented by a circle spaced along the respective vertical lines, and a solid line extending between the circles represents the arrangement of the intermediate frame 106 based on the corresponding positions of the actuators 150, 152. A dash-dot-dash horizontal line represents aflat configuration CF at the head reference position RH and at the foot reference position RF (e.g., see Figure 15B). A wide dash horizontal line represents a flat configuration CF at a lowered intermediate configuration CI (e.g., see Figure 15C).

[0122] Figures 16A-16C sequentially depict a scenario where the patient transport apparatus 100 has been placed into a Trendelenburg configuration CT and a depletion of charge in the battery 160 (or some other event) has resulted in the patient transport apparatus controller 158 being unable to drive the actuators 150, 152 in the operational mode. Here in this illustrative example scenario, Figure 16A depicts the intermediate frame 106 being angled at approximately 11 -degrees with the head end actuator 150 disposed at the head reference position RH and with the foot end actuator 152 being disposed above the foot reference position RF. From this Trendelenburg configuration CT, user engagement of the backup system 200 will result in the head end actuator 150 remaining stationary at the head reference position RH due to the head switch 242 preventing power from being routed to the head end actuator 150 as described above, but the foot end actuator 152 will begin lowering towards the foot reference position RF as depicted with the downward arrow in Figure 16A until the foot reference position RF is reached as depicted in Figure 16B, which shows the intermediate frame 106 arranged in a flat configuration CF. Here, because both reference positions RH, RF have been achieved, continued operation of the backup system 200 will result in both actuators 150, 152 subsequently lowering further towards the wide dash horizontal line as depicted by the downward arrows in Figure 16B until the lowered intermediate configuration CI is reached in Figure 16C. Here, it will be appreciated that the lowered intermediate configuration CI could be defined in various ways, and may be adjustable or otherwise able to be set by a user in some versions.

[0123] In order to achieve the lowered intermediate configuration CI via operation of the backup system 200, the sensing system 238 may employ additional sensors S, such as for example a lower head switch 248 and / or a lower foot switch 250 used to intermpt operation of the backup system 200 once the lowered intermediate configuration CI has been achieved. Like the switches 242, 244, 246 described above, the lower switches 248, 250 may likewise be arranged internally or externally relative to the actuators 150, 152, or may be mounted on other portions of the patient transport apparatus 100, may be configured to either directly or indirectly (e.g., via activation of a relay) intermpt directing power to the actuators 150, 152, and may be of various styles, types, and or arrangements. In some versions, only a single lower switch 248, 250 may be utilized. Other configurations are contemplated, and it will be appreciated that the backup system 200 could be configured to drive the actuators 150, 152 to bring the intermediate frame 106 from the flat configuration CF at the reference positions RH, RF depicted in Figure 16B to the flat configuration CF at the lowered intermediate configuration CI depicted in Figure 16C in other ways.

[0124] It will be appreciated that the scenario described above in connection with Figures 16A-16C is directed towards moving the intermediate frame 106 into the lowered intermediate configuration CI via operation of the backup system 200 (e.g., see Figure 15C), as opposed to moving the intermediate frame 106 into the maximum lowered configuration CL (e.g., see Figure 15D). Here, the lowered intermediate configuration CI may be set higher than the maximum lowered configuration CL for various reasons, such as to ideally position the intermediate frame 106 for caregiver access to the patient for performing cardiopulmonary resuscitation CPR, and or so as to help facilitate proper operation of other components of the patient transport apparatus 100 once the battery 160 charge has been replenished, at which point the maximum lowered configuration CL could be achieved via the operational mode without the backup system 200.

[0125] In some versions, depending on the configuration of the support structure 102 and the relative arrangement of the load cells 240 of the sensing system 238, it may be advantageous for the intermediate frame 106 to be spaced vertically above the base 104 before the operational mode is reactivated, such as to ensure that the scale, bed exit, and other systems can be properly initialized, armed, and the like. However, other configurations are contemplated, and in some versions the backup system 200 may be configured to instead lower the intermediate frame 106 all the way to the maximum lowered configuration CL. In such versions, the patient transport apparatus controller 158 and / or other portions of the patient transport apparatus 100 and / or patient transport system 98 may be configured so as to alert the user of the need to raise the intermediate frame 106, and may initially disable operation of scale, bed exit, and other systems which rely on the load cells 240 until the intermediate frame 106 has been moved to a configuration which facilitates proper initialization. This functionality may also be utilized in connection with versions where the sensing system 238 utilizes different types of switches 242, 244 to detect the actuators 150, 152 relative to the reference positions RH, RF, such as where the switches 242, 244 are arranged on the intermediate frame 106 and / or the base 104 to sense physical contact, and / or in scenarios where the relative arrangement of the load cells 240 and the switches 242, 244 otherwise results in the load cells 240 inaccurately measuring load distribution due to contact occurring between the switches 242, 244 and a portion of the support structure 102.

[0126] As noted above, the lowered intermediate configuration CI to which the actuators 150, 152 are moved via operation of the backup system 200 may be adjustable in some versions, such as by repositioning the lower switches 248, 250. Similarly, the reference positions RH, RF may be adjustable in some versions, such as by repositioning the head switches 242, 244. In some versions, the reference positions RH, RF may represent a distance between the loweredintermediate configuration CI and the maximum lowered configuration CL (e.g., 50- 100mm above the maximum lowered configuration CL).

[0127] It will be appreciated that the reference positions RH, RF may be set or otherwise determined based on the configuration of the support structure 102, the actuators 150, 152, and / or other portions of the patient transport apparatus 100. For example, the reference positions RH, RF utilized on a patient transport apparatus 100 which is capable of achieving an 11-degree Trendelenburg configuration CT may be different (e.g., lower) than the reference positions RH, RF utilized on a patient transport apparatus 100 which is capable of achieving a 14-degree Trendelenburg configuration CT. In some versions, the sensing system 238 may include an upper head switch 252 and an upper foot switch 254 separate from the head switch 242 and the foot switch 244 to facilitate defining a second head reference position RH2 and a second foot reference position RF2 to accommodate scenarios where multiple angle Trendelenburg configurations CT may be utilized.

[0128] For example, Figures 17A-17C sequentially depict a scenario where the patient transport apparatus 100 has been placed into a 14-degree Trendelenburg configuration CT and a depletion of charge in the battery 160 (or some other event) has resulted in the patient transport apparatus controller 158 being unable to drive the actuators 150, 152 in the operational mode. Here in this illustrative example scenario, Figure 17A depicts the inteimediate frame 106 being angled at approximately 14-degrees with the head end actuator 150 disposed at the second head reference position RH2 and with the foot end actuator 152 being disposed above the second foot reference position RF2. From this Trendelenburg configuration CT, user engagement of the backup system 200 will result in the head end actuator 150 remaining stationary at the second head reference position RH2 due to the head switch 242 preventing power from being routed to the headend actuator 150 as described above, but the foot end actuator 152 will begin lowering towards the second foot reference position RF2 as depicted with the downward arrow in Figure 17A until the second foot reference position RF2 is reached as depicted in Figure 17B, which shows the intermediate frame 106 arranged in a flat configuration CF. Continuing from Figure 17A to Figure 17B, because both second reference positions RH2, RF2 have been achieved, continued operation of the backup system 200 will result in both actuators 150, 152 subsequently lowering further towards the wide dash horizontal line as depicted by the downward arrows in Figure 17B until the lowered intermediate configuration CI is reached in Figure 17C.

[0129] In this version, the backup system 200 could be configured so as to rely on the upper switches 252, 254 rather than the switches 242, 244 based such as on the angle switch 246, which may be configured to energize relays or otherwise activate a circuit which enables the upper switches 252, 254 and disables the switches 242, 244 when the intermediate frame 106 is angled beyond some predetermined threshold (e.g., more than 13-degrees), and which instead enables the switches 242, 244 and disables the upper switches 252, 254 when the intermediate frame 106 is angled below that predetermined threshold (e.g., less than 13-degrees). Other configurations are contemplated.

[0130] Figures 18A-18D sequentially depict a scenario where the patient transport apparatus 100 has been placed into an elevated Trendelenburg configuration CT and a depletion of charge in the battery 160 (or some other event) has resulted in the patient transport apparatus controller 158 being unable to drive the actuators 150, 152 in the operational mode. Here in this illustrative example scenario, Figure 18A depicts the intermediate frame 106 being angled at approximately 8-degrees with the head end actuator 150 disposed above the head reference position RH and with the foot end actuator 152 being disposed above the foot reference positionRF and higher than the head-end actuator 150. From this Trendelenburg configuration CT, user engagement of the backup system 200 will result in the head end actuator 150 and the foot end actuator 152 both lowering towards the respective reference positions RH, RF as depicted with the downward arrows in Figure 18A until the head reference position RH is reached as depicted in Figure 18B. Here, the head end actuator 150 will stop moving and remain stationary at the head reference position RH due to the head switch 242 preventing power from being routed to the head end actuator 150 as described above, but the foot end actuator 152 will continue lowering towards the foot reference position RF as depicted with the downward arrow in Figure 18B until the foot reference position RF is reached as depicted in Figure 18C, which shows the intermediate frame 106 arranged in a flat configuration CF. Here, because both reference positions RH, RF have been achieved, continued operation of the backup system 200 will result in both actuators 150, 152 subsequently lowering further towards the wide dash horizontal line as depicted by the downward arrows in Figure 18C until the lowered intermediate configuration CI is reached in Figure 18D.

[0131] Figures 19A-19C sequentially depict a scenario where the patient transport apparatus 100 has been placed into a low Trendelenburg configuration CT and a depletion of charge in the battery 160 (or some other event) has resulted in the patient transport apparatus controller 158 being unable to drive the actuators 150, 152 in the operational mode. Here in this illustrative example scenario, Figure 19A depicts the intermediate frame 106 being angled at approximately 8-degrees with the head end actuator 150 disposed below the head reference position RH and with the foot end actuator 152 being disposed above the foot reference position RF. From this low Trendelenburg configuration CT, user engagement of the backup system 200 will result in the head end actuator 150 remaining stationary below the head reference position RH due to the head switch 242 preventing power from being routed to the head end actuator 150 asdescribed above, but the foot end actuator 152 will begin lowering towards the foot reference position RF as depicted with the downward arrow in Figure 19A until the foot reference position RF is reached as depicted in Figure 19B, which shows the intermediate frame 106 arranged in a slight Trendelenburg configuration CF. Here, because both reference positions RH, RF have been achieved (e.g., with both actuators 150, 152 arranged at or below the reference positions RH, RF), continued operation of the backup system 200 will result in both actuators 150, 152 subsequently lowering further towards the wide dash horizontal line as depicted by the downward arrows in Figure 19BB until the lowered intermediate configuration CI is reached in Figure 19C.

[0132] As noted above, in some versions, the sensing system 238 could be configured without necessarily utilizing the switches 242, 244 to allow operation of the backup system 200 to lower the intermediate frame 106. For example, rather than utilizing the switches 242, 244 to lower each actuator 150, 152 that is above the respective reference position RH, RF, the sensing system 238 could instead utilize the angle switch 246 to facilitate moving the whichever actuator 150, 152 is higher down to the same height as the other actuator 150, 152. Figures 20A-20C sequentially depict a scenario where the patient transport apparatus 100 has been placed into an elevated reverse Trendelenburg configuration CV and a depletion of charge in the battery 160 (or some other event) has resulted in the patient transport apparatus controller 158 being unable to drive the actuators 150, 152 in the operational mode. Here in this illustrative example scenario, Figure 20 A depicts the intermediate frame 106 being angled at approximately 10-degrees with the head end actuator 150 disposed above the head reference position RH and with the foot end actuator 152 being disposed above the foot reference position RF but below the head end actuator 150. From this elevated reverse Trendelenburg configuration CV, user engagement of the backup system 200 will result in the foot end actuator 152 remaining stationary due to the angle switch246 determining that the head end actuator 150 is higher than the foot end actuator 152, but will allow to the head end actuator 150 to begin lowering towards the foot end actuator 152 as depicted with the downward arrow in Figure 20A until the flat configuration CF is reached as depicted in Figure 20B. Here, because the angle switch 246 has determined that the actuators 150, 152 are at the same height, continued operation of the backup system 200 will result in both actuators 150, 152 subsequently lowering towards the wide dash horizontal line as depicted by the downward arrows in Figure 20B until the lowered intermediate configuration CI is reached in Figure 20C.

[0133] It will be appreciated that aspects of the scenario described above in connection with Figures 20A-20C may be implemented in connection with other scenarios described herein. In some versions, the angle switch 246 could be utilized along with the switches 242, 244 so as to operate the actuators 150, 152 differently depending on whether the intermediate frame 106 is arranged in a Trendelenburg configuration CT or a reverse Trendelenburg configuration CV. By way of non-limiting example, the switches 242, 244 may be utilized to follow one of the scenarios described above in connection with Figures 16A-19C based on the angle switch 246 indicating a Trendelenburg configuration CT, but the switches 242, 244 may be disabled and the scenario described above in connection with Figures 20A-20C may be followed when the angle switch 246 indicates a reverse Trendelenburg configuration CV. Similarly, in some versions, the switches 242, 244 may be utilized to define the reference positions RH, RF based on the angle switch 246 indicating a Trendelenburg configuration CT, but the upper switches 252, 254 may instead be utilized to define the second reference positions RH2, RF2 based on the angle switch 246 indicating a reverse Trendelenburg configuration CV. Other configurations are contemplated.

[0134] Figures 21A-21C sequentially depict a scenario where the patient transport apparatus 100 has been placed into a Trendelenburg configuration CT and a depletion of charge inthe battery 160 (or some other event) has resulted in the patient transport apparatus controller 158 being unable to drive the actuators 150, 152 in the operational mode. Here in this illustrative example scenario, Figure 21A depicts the intermediate frame 106 being angled at approximately 9-degrees with the head end actuator 150 disposed below the head reference position RH and with the foot end actuator 152 being disposed at the foot reference position RF. From this Trendelenburg configuration CT, user engagement of the backup system 200 will result in the foot end actuator 150 remaining stationary at the foot reference position RF due to the foot switch 244 preventing power from being routed to the foot end actuator 152 as described above, but the head end actuator 150 will begin raising towards the head reference position RH as depicted with the upward arrow in Figure 21 A until the head reference position RH is reached as depicted in Figure 21B, which shows the intermediate frame 106 arranged in a flat configuration CF. Here, because both reference positions RH, RF have been achieved, in some versions, continued operation of the backup system 200 will result in both actuators 150, 152 subsequently lowering towards the wide dash horizontal line as depicted by the downward arrows in Figure 2 IB until the lowered intermediate configuration CI is reached in Figure 21C.

[0135] Figures 22A-22D sequentially depict a scenario where the patient transport apparatus 100 has been placed into a lowered Trendelenburg configuration CT and a depletion of charge in the battery 160 (or some other event) has resulted in the patient transport apparatus controller 158 being unable to drive the actuators 150, 152 in the operational mode. Here in this illustrative example scenario, Figure 22A depicts the intermediate frame 106 being angled at approximately 6-degrees with the head end actuator 150 disposed below the head reference position RH and with the foot end actuator 152 being disposed below the foot reference positionRF but higher than the head-end actuator 150. From this Trendelenburg configuration CT, userengagement of the backup system 200 will result in the head end actuator 150 and the foot end actuator 152 both raising towards the respective reference positions RH, RF as depicted with the upward arrows in Figure 22A until the foot reference position RF is reached as depicted in Figure 22B. Here, the foot end actuator 152 will stop moving and remain stationary at the foot reference position RF due to the foot switch 244 preventing power from being routed to the foot end actuator 152 as described above, but the head end actuator 150 will continue raising towards the head reference position RH as depicted with the upward arrow in Figure 22B until the head reference position RH is reached as depicted in Figure 22C, which shows the intermediate frame 106 arranged in a flat configuration CF. Here, because both reference positions RH, RF have been achieved, continued operation of the backup system 200 will result in both actuators 150, 152 subsequently lowering towards the wide dash horizontal line as depicted by the downward arrows in Figure 22C until the lowered intermediate configuration CI is reached in Figure 22D.

[0136] Figures 23A-23C sequentially depict a scenario where the patient transport apparatus 100 has been placed into a lowered Trendelenburg configuration CT and a depletion of charge in the battery 160 (or some other event) has resulted in the patient transport apparatus controller 158 being unable to drive the actuators 150, 152 in the operational mode. Here in this illustrative example scenario, Figure 23 A depicts the intermediate frame 106 being angled at approximately 6-degrees with the head end actuator 150 disposed below the head reference position RH and with the foot end actuator 152 being disposed below the foot reference position RF but higher than the head-end actuator 150. From this Trendelenburg configuration CT, in some versions, user engagement of the backup system 200 will result in the foot end actuator 152 remaining stationary due to the angle switch 246 determining that the head end actuator 150 is lower than the foot end actuator 152 and that one or more of the switches 242, 244 indicate thatthe intermediate frame 106 is positioned below one or more of the reference positions RH, RF, but will allow to the head end actuator 150 to begin raising towards the foot end actuator 152 as depicted with the upward arrow in Figure 23A until the flat configuration CF is reached as depicted in Figure 23B. Here, because the angle switch 246 has determined that the actuators 150, 152 are at the same height, continued operation of the backup system 200 will result in both actuators 150, 152 subsequently lowering towards the wide dash horizontal line as depicted by the downward arrows in Figure 23B until the lowered intermediate configuration CI is reached in Figure 23C.

[0137] It will be appreciated that, depending on the configuration of the switching circuit 214, the switches 242, 244, 246, 248, 250, 252, 254, the primary user input device 164, the backup system 200, the backup user input device 204, and / or other components of the patient transport apparatus 100, the intermediate frame 106 could be moved in various ways during operation in the backup mode. By way of non-limiting example, in some versions the backup system may be configured with two backup user input devices 204; one associated with the head end actuator 150 and another associated with the foot end actuator 150. Here, for example, if the backup user input devices 204 could be configured similarly to as is depicted in Figure 12 A, with each having a respective first and second backup input control 216A, 216B. While various configurations are contemplated, in some versions each of the two backup user input devices 204 could be arranged for user engagement to allow either of the first backup input controls 216A to be utilized to raise the intermediate frame 106 and to allow either of the second backup input controls 216B to be utilized to lower the intermediate frame 106. In other versions, the backup user input device 204 associated with the head end actuator 150 could be employed to allow control of the head end actuator 150 but not the foot end actuator 152, while the backup user input device 204 associated with the foot end actuator 152 could be employed to allow control of the foot end actuator 152 butnot the head end actuator 152. Here, for example, the first backup input control 216A of the backup user input device 204 associated with the head end actuator 150 could raise the head end actuator 150 under certain conditions (e.g., if one or more switches 242, 244 indicate that the actuators 150, 152 are below the reference positions RH, RF), and the second backup input control 216B of the backup user input device 204 associated with the head end actuator 150 could lower the head end actuator 150 under certain conditions (e.g., if one or more switches 242, 244 indicate that the actuators 150, 152 are above the reference positions RH, RF).

[0138] In versions where backup user input devices 204 employ first and second backup input controls 216A, 216B and / or where multiple switches 242, 244, 248, 250, 252, 254 are utilized for each actuator 150, 152 to define multiple configurations, heights, reference positions, and the like as described above, certain scenarios described herein could result in the intermediate frame 106 remaining at one of the flat configurations CF after one or both actuators 150, 152 have been driven in the backup mode so as to at least partially raise the respective actuator 150, 152 in response to user engagement with a backup input control 216A configured to raise one or more of the actuators 150, 152, such as to remain at the configurations depicted in Figures 21B, 22C, 23B, and the like rather than subsequently lowering further towards some other lowered flat configuration CF (e.g., as described above). However, in some versions, such as where the backup user input devices 204 employ only a single backup input control 216, it will be appreciated that lowering the intermediate frame 106 may involve first raising one or more actuators 150, 152 to a flat configuration CF before subsequently lowering the intermediate frame 106 as described above. Oher configurations are contemplated.

[0139] Figures 24A-24D sequentially depict a scenario where the patient transport apparatus 100 has been placed into a lowered Trendelenburg configuration CT and a depletion ofcharge in the battery 160 (or some other event) has resulted in the patient transport apparatus controller 158 being unable to drive the actuators 150, 152 in the operational mode. Here in this illustrative example scenario, Figure 24A depicts the intermediate frame 106 being angled at approximately 6-degrees with the head end actuator 150 disposed below the head reference position RH and with the foot end actuator 152 being disposed below the foot reference position RF but higher than the head-end actuator 150. Here too in this illustrative scenario, the backup system 200 is configured with separate backup user input devices 204 associated with each respective actuator 150, 152. From this Trendelenburg configuration CT depicted in Figure 24A, user engagement of the backup user input device 204 of the backup system 200 that is associated with the head end actuator 150 will result in the head end actuator 150 raising towards the head reference position RH as depicted with an upward arrow in Figure 24A until the head reference position RH is reached as depicted in Figure 24B. From this reverse Trendelenburg configuration CV depicted in Figure 24B, which is arranged at approximately 3-degrees, user engagement of the backup user input device 204 of the backup system 200 that is associated with the foot end actuator 152 will result in the foot end actuator 152 raising towards the foot reference position RF as depicted with an upward arrow in Figure 24B until the foot reference position RF is reached as depicted in Figure 24C, which shows the intermediate frame 106 arranged in a flat configuration CF. Here, because both reference positions RH, RF have been achieved, continued operation of the backup system 200 will result in both actuators 150, 152 subsequently lowering towards the wide dash horizontal line as depicted by the downward arrows in Figure 24C until the lowered intermediate configuration CI is reached in Figure 24D.

[0140] Figures 25A-25D sequentially depict a scenario where the patient transport apparatus 100 has been placed into a lowered Trendelenburg configuration CT and a depletion ofcharge in the battery 160 (or some other event) has resulted in the patient transport apparatus controller 158 being unable to drive the actuators 150, 152 in the operational mode. Here in this illustrative example scenario, Figure 25A depicts the intermediate frame 106 being angled at approximately 6-degrees with the head end actuator 150 disposed below the head reference position RH and with the foot end actuator 152 being disposed below the foot reference position RF but higher than the head-end actuator 150. From this Trendelenburg configuration CT, in some versions, user engagement of the backup system 200 will result in the foot end actuator 152 remaining stationary due to the angle switch 246 determining that the head end actuator 150 is lower than the foot end actuator 152 and that the switches 242, 244 indicate that the intermediate frame 106 is positioned below the reference positions RH, RF, but will allow to the head end actuator 150 to begin raising towards the foot end actuator 152 as depicted with the upward arrow in Figure 25 A until the flat configuration CF is reached as depicted in Figure 25B. Here, because the angle switch 246 has determined that the actuators 150, 152 are at the same height but both actuators 150, 152 are below the respective reference positions RH, RF, continued operation of the backup system 200 will result in the head end actuator 150 and the foot end actuator 152 both raising towards the respective reference positions RH, RF as depicted with the upward arrows in Figure 25A until the reference positions RH, RF are reached as depicted in Figure 25C. At this point, continued operation of the backup system 200 will result in both actuators 150, 152 subsequently lowering towards the wide dash horizontal line as depicted by the downward arrows in Figure 25C until the lowered intermediate configuration CI is reached in Figure 25D. It will be appreciated that this scenario could, alternatively, end with the arrangement of the intermediate frame 106 depicted in Figure 25B (e.g., once a flat configuration CF is achieved), or with the arrangement of the intermediate frame 106 depicted in Figure 25C (e.g., at the reference positionsRH, RF), or could instead progress as described in connection with Figures 23A-23C (e.g., proceed from the flat configuration CF to the lowered flat configuration CF without first raising to the reference positions RH, RF). Other configurations are contemplated.

[0141] Several examples have been discussed in the foregoing description. However, the examples discussed herein are not intended to be exhaustive or limit the disclosure to any particular form. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the scope of the disclosure. The terminology that has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations are possible in light of the above teachings and the disclosure may be practiced otherwise than as specifically described.

[0142] The present disclosure also comprises the following clauses, with specific features laid out in dependent clauses, that may specifically be implemented as described in greater detail with reference to the configurations and drawings above.CLAUSESI. A patient transport apparatus for supporting a patient, the patient transport apparatus comprising: a support structure defining a head end and a foot end, the support structure including: a base; a litter operatively attached to the base and including an intermediate frame having a patient support deck; and a lift assembly arranged between the base and the intermediate frame and configured to adjust the pose of the litter relative to the base, the lift assembly including: a foot end actuator configured to raise and lower the intermediate frame relative to the base adjacent to the foot end, anda head end actuator arranged to raise and lower the intermediate frame relative to the base adjacent to the head end; a battery for providing power to the patient transport apparatus; a primary user input device coupled to the support structure and arranged for user engagement to operate the lift assembly; a patient transport apparatus controller disposed in electrical communication with the lift assembly, the battery, and the primary user input device, the patient transport apparatus controller configured to operate the lift assembly between a suspended mode and an operating mode to drive the lift assembly with power from the battery in response to user engagement with the primary user input device when a charge state of the battery is above a predetermined charge threshold; a backup system for operating the lift assembly during operation of the patient transport apparatus in the suspended mode, the backup system including a backup user input device coupled to the support structure and in electrical communication with the battery and the lift assembly, the backup user input device arranged for user engagement to operate the lift assembly when the patient transport apparatus controller is in the suspended mode; and a sensing system in communication with the backup system, the sensing system including at least one sensor configured to provide signals representative of the pose of the litter to the backup system, and based on the signals representative of the pose of the litter, the backup system is configured to operate the lift assembly to prevent collisions of the litter with floor surfaces during operation of the lift assembly in the suspended mode.II. The patient transport apparatus of clause I, wherein, based on the signals representative of the pose of the litter, the backup system is configured to coordinate operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces during operation of the lift assembly in the suspended mode.III. The patient transport apparatus of clause II, wherein coordination of operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces includes starting operation of one of the head end actuator and the foot end actuator before the other of the head end actuator and the foot end actuator.IV. The patient transport apparatus of any one of clauses II or III, wherein coordination of operation of the head end actuator and the foot end actuator to prevent collisions of the litter withfloor surfaces includes stopping operation of one of the head end actuator and the foot end actuator before the other of the head end actuator and the foot end actuator.V. The patient transport apparatus of any one of clauses II to IV, wherein coordination of operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces includes operating of one of the head end actuator and the foot end actuator at a different speed than the other of the head end actuator and the foot end actuator.VI. The patient transport apparatus of any one of clauses I to V, wherein the at least one sensor of the sensing system includes; a head switch operatively attached to the head end actuator and configured to determine whether the head end actuator is extended above or retracted below a predetermined head end reference position; and a foot switch operatively attached to the foot end actuator and configured to determine whether the foot end actuator is extended above or retracted below a predetermined foot end reference position.VII. The patient transport apparatus of clause VI, wherein, based on whether the head end actuator is extended above or retracted below a predetermined head end reference position and based on whether the foot end actuator is extended above or retracted below a predetermined foot end reference position, the backup system is configured to operate the lift assembly to prevent collisions of the litter with floor surfaces during operation of the lift assembly in the suspended mode.VIII. The patient transport apparatus of clause VII, wherein the backup user input device is interposed between the battery and the lift assembly, with the backup user input device being configured for user-selected operation between: an interrupt state defined by interrupted electrical communication between the battery and the lift assembly, and a drive state defined by electrical communication between the battery and the lift assembly.IX. The patient transport appar atus of clause VIII, wherein the backup user input device includes a switching circuit to operate the backup user input device between the interrupt state and the drive state in response to user engagement with the backup user input device.X. The patient transport apparatus of clause IX, wherein the head switch and the foot switch are in communication with the switching circuit to coordinate operation of the head endactuator and the foot end actuator to prevent collisions of the litter with floor surfaces during operation of the backup user input device in the drive state.XI. The patient transport apparatus of clause X, wherein, in response to operation of the backup user input device in the drive state, the head switch is configured to route power from the battery to the head end actuator based on i) whether the head end actuator is extended above or retracted below the predetermined head end reference position, and ii) whether the foot end actuator is extended above or retracted below the predetermined foot end reference position to coordinate operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces.XII. The patient transport apparatus of any one of clauses X or XI, wherein, in response to operation of the backup user input device in the drive state, the foot switch is configured to route power from the battery to the foot end actuator based on i) whether the head end actuator is extended above or retracted below the predetermined head end reference position, and ii) whether the foot end actuator is extended above or retracted below the predetermined foot end reference position to coordinate operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces.XIII. The patient transport apparatus of any one of clauses I to XII, wherein the at least one sensor of the sensing system includes an angle sensor configured to generate signals representative of the angle of the litter relative to the base, and based on the signals representative of the angle of the litter relative to the base, the backup system is configured to coordinate operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces during operation of the lift assembly in the suspended mode.XIV. The patient transport apparatus of any one of clauses I to XIII, wherein the sensing system is in communication with the patient transport apparatus controller; and wherein the at least one sensor of the sensing system is further configured to provide signals representative of the pose of the litter to the patient transport apparatus controller, and based on the signals representative of the pose of the litter, the patient transport apparatus controller is configured to operate the lift assembly to prevent collisions of the litter with floor surfaces during operation of the lift assembly in the operating mode.XV. The patient transport apparatus of clause XIV, wherein the at least one sensor of the sensing system includes:a head end actuator position sensor configured to generate signals representative of the extension of the head end actuator; and a foot end actuator position sensor configured to generate signals representative of the extension of the foot end actuator.XVI. The patient transport apparatus of clause XV, wherein the head end actuator position sensor and the foot end actuator position sensor are configured to provide the signals representative of the extension of the head end actuator and the extension of the foot end actuator to the patient transport apparatus controller; and wherein, based on the signals representative of the extension of the head end actuator and the extension of the foot end actuator, the patient transport apparatus controller is configured to operate the lift assembly to prevent collisions of the litter with floor surfaces during operation of the lift assembly in the operating mode.XVII. The patient transport apparatus of any one of clauses I to XVI, wherein the predeteimined charge threshold is defined as a state of charge to permit a predeteimined number of articulations of the head end actuator and the foot end actuator reserved for emergency situations.XVIII. The patient transport apparatus of any one of clauses I to XVII, wherein the primary user input device is disposed on the intermediate frame.XIX. The patient transport appar atus of any one of clauses I to XVIII, wherein the backup user input device is disposed on the base.XX. The patient transport apparatus of any one of clauses I to XIX, wherein the backup user input device includes: a first backup input control arranged for user engagement to operate the lift assembly in a first direction to raise the litter relative to the base, and a second backup input control arranged for user engagement to operate the lift assembly in a second direction to lower the litter relative to the base.XXI. The patient transport apparatus of any one of clauses I to XX, wherein the backup user input device is interposed between the battery and the lift assembly, with the backup user input device being configured for user-selected operation between: an interrupt state defined by interrupted electrical communication between the battery and the lift assembly, anda drive state defined by electrical communication between the battery and the lift assembly; and wherein the backup user input device includes a switching circuit to operate the backup user input device between the interrupt state and the drive state in response to user engagement with the backup user input device.XXII. The patient transport apparatus of clause XXI, wherein the switching circuit includes: a raise switch operable between: a raise switch interrupt state where the battery and the lift assembly are electrically decoupled, and a raise switch drive state where the battery and the lift assembly are electrically coupled to power the lift assembly to raise litter relative to the base; and a lower switch operable between: a lower switch interrupt state where the battery and the lift assembly are electrically decoupled, and a lower switch drive state where the battery and the lift assembly are electrically coupled to power the lift assembly to lower the litter relative to the base.

Claims

CLAIMSWhat is claimed is:

1. A patient transport apparatus for supporting a patient, the patient transport apparatus comprising: a support structure defining a head end and a foot end, the support structure including: a base; a litter operatively attached to the base and including an intermediate frame having a patient support deck; and a lift assembly arranged between the base and the intermediate frame and configured to adjust the pose of the litter relative to the base, the lift assembly including: a foot end actuator configured to raise and lower the intermediate frame relative to the base adjacent to the foot end, and a head end actuator arranged to raise and lower the intermediate frame relative to the base adjacent to the head end; a battery for providing power to the patient transport apparatus; a primary user input device coupled to the support structure and arranged for user engagement to operate the lift assembly; a patient transport apparatus controller disposed in electrical communication with the lift assembly, the battery, and the primary user input device, the patient transport apparatus controller configured to operate the lift assembly between a suspended mode and an operating mode to drive the lift assembly with power from the battery in response to user engagement with the primary user input device when a charge state of the battery is above a predetermined charge threshold; a backup system for operating the lift assembly during operation of the patient transport apparatus in the suspended mode, the backup system including a backup user input device coupled to the support structure and in electrical communication with the battery and the lift assembly, the backup user input device arranged for user engagement to operate the lift assembly when the patient transport apparatus controller is in the suspended mode; and a sensing system in communication with the backup system, the sensing system including at least one sensor configured to provide signals representative of the pose of the litter to the backup system, and based on the signals representative of the pose of the litter, the backup systemis configured to operate the lift assembly to prevent collisions of the litter with floor surfaces during operation of the lift assembly in the suspended mode.

2. The patient transport apparatus of claim 1, wherein, based on the signals representative of the pose of the litter, the backup system is configured to coordinate operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces during operation of the lift assembly in the suspended mode.

3. The patient transport apparatus of claim 2, wherein coordination of operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces includes starting operation of one of the head end actuator and the foot end actuator before the other of the head end actuator and the foot end actuator.

4. The patient transport apparatus of claim 2, wherein coordination of operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces includes stopping operation of one of the head end actuator and the foot end actuator before the other of the head end actuator and the foot end actuator.

5. The patient transport apparatus of claim 2, wherein coordination of operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces includes operating of one of the head end actuator and the foot end actuator at a different speed than the other of the head end actuator and the foot end actuator.

6. The patient transport apparatus of claim 1, wherein the at least one sensor of the sensing system includes: a head switch operatively attached to the head end actuator and configured to determine whether the head end actuator is extended above or retracted below a predetermined head end reference position; and a foot switch operatively attached to the foot end actuator and configured to determine whether the foot end actuator is extended above or retracted below a predetermined foot end reference position.

7. The patient transport apparatus of claim 6, wherein, based on whether the head end actuator is extended above or retracted below a predetermined head end reference position and based on whether the foot end actuator is extended above or retracted below a predetermined foot end reference position, the backup system is configured to operate the lift assembly to prevent collisions of the litter with floor surfaces during operation of the lift assembly in the suspended mode.

8. The patient transport apparatus of claim 7, wherein the backup user input device is interposed between the battery and the lift assembly, with the backup user input device being configured for user-selected operation between: an interrupt state defined by interrupted electrical communication between the battery and the lift assembly, and a drive state defined by electrical communication between the battery and the lift assembly.

9. The patient transport apparatus of claim 8, wherein the backup user input device includes a switching circuit to operate the backup user input device between the interrupt state and the drive state in response to user engagement with the backup user input device.

10. The patient transport apparatus of claim 9, wherein the head switch and the foot switch are in communication with the switching circuit to coordinate operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces during operation of the backup user input device in the drive state.

11. The patient transport apparatus of claim 10, wherein, in response to operation of the backup user input device in the drive state, the head switch is configured to route power from the battery to the head end actuator based on i) whether the head end actuator is extended above or retracted below the predetermined head end reference position, and ii) whether the foot end actuator is extended above or retracted below the predetermined foot end reference position to coordinate operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces.

12. The patient transport apparatus of claim 10, wherein, in response to operation of the backup user input device in the drive state, the foot switch is configured to route power from the battery to the foot end actuator based on i) whether the head end actuator is extended above or retracted below the predetermined head end reference position, and ii) whether the foot end actuator is extended above or retracted below the predetermined foot end reference position to coordinate operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces.

13. The patient transport apparatus of claim 1, wherein the at least one sensor of the sensing system includes an angle sensor configured to generate signals representative of the angle of the litter relative to the base, and based on the signals representative of the angle of the litter relative to the base, the backup system is configured to coordinate operation of the head end actuator and the foot end actuator to prevent collisions of the litter with floor surfaces during operation of the lift assembly in the suspended mode.

14. The patient transport apparatus of claim 1, wherein the sensing system is in communication with the patient transport apparatus controller; and wherein the at least one sensor of the sensing system is further configured to provide signals representative of the pose of the litter to the patient transport apparatus controller, and based on the signals representative of the pose of the litter, the patient transport apparatus controller is configured to operate the lift assembly to prevent collisions of the litter with floor surfaces during operation of the lift assembly in the operating mode.

15. The patient transport apparatus of claim 14, wherein the at least one sensor of the sensing system includes: a head end actuator position sensor configured to generate signals representative of the extension of the head end actuator; and a foot end actuator position sensor configured to generate signals representative of the extension of the foot end actuator.

16. The patient transport apparatus of claim 15, wherein the head end actuator position sensor and the foot end actuator position sensor arc configured to provide the signals representative of the extension of the head end actuator and the extension of the foot end actuator to the patient transport apparatus controller; and wherein, based on the signals representative of the extension of the head end actuator and the extension of the foot end actuator, the patient transport apparatus controller is configured to operate the lift assembly to prevent collisions of the litter with floor surfaces during operation of the lift assembly in the operating mode.

17. The patient transport apparatus of claim 1, wherein the predetermined charge threshold is defined as a state of charge to permit a predetermined number of articulations of the head end actuator and the foot end actuator reserved for emergency situations.

18. The patient transport apparatus of claim 1, wherein the primary user input device is disposed on the intermediate frame.

19. The patient transport apparatus of claim 1, wherein the backup user input device is disposed on the base.

20. The patient transport apparatus of claim 1, wherein the backup user input device includes: a first backup input control arranged for user engagement to operate the lift assembly in a first direction to raise the litter relative to the base, and a second backup input control arranged for user engagement to operate the lift assembly in a second direction to lower the litter relative to the base.

21. The patient transport appar atus of claim 1, wherein the backup user input device is interposed between the battery and the lift assembly, with the backup user input device being configured for user-selected operation between: an interrupt state defined by interrupted electrical communication between the battery and the lift assembly, anda drive state defined by electrical communication between the battery and the lift assembly; and wherein the backup user input device includes a switching circuit to operate the backup user input device between the interrupt state and the drive state in response to user engagement with the backup user input device.

22. The patient transport apparatus of claim 21, wherein the switching circuit includes: a raise switch operable between: a raise switch interrupt state where the battery and the lift assembly are electrically decoupled, and a raise switch drive state where the battery and the lift assembly are electrically coupled to power the lift assembly to raise litter relative to the base; and a lower switch operable between: a lower switch interrupt state where the battery and the lift assembly are electrically decoupled, and a lower switch drive state where the battery and the lift assembly are electrically coupled to power the lift assembly to lower the litter relative to the base.

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