Patent Application
20210386603
Patient transport systems facilitate care of patients in a health care setting. Patient transport systems comprise patient transport apparatuses such as, for example, hospital beds and stretchers, to move patients between locations. A conventional patient transport apparatus comprises a base, a patient support surface, and several support wheels, such as four swiveling caster wheels. Often, the patient transport apparatus has one or more non-swiveling auxiliary wheels, in addition to the four caster wheels. The auxiliary wheels, by virtue of their non-swiveling nature, are employed to help control movement of the patient transport apparatus over a floor surface in certain situations.
When a caregiver wishes to use the auxiliary wheels to help control movement of the patient transport apparatus, such as down long hallways or around corners, the caregiver moves the auxiliary wheels from a stowed position, out of contact with the floor surface, to a deployed position in contact with the floor surface. This is usually accomplished with a foot pedal that deploys the auxiliary wheels through a mechanical linkage. In many cases, it's desirable for the auxiliary wheels to lift a pair of the caster wheels off the floor surface to enhance the maneuverability of the patient transport apparatus. However, if a load to be carried by the auxiliary wheels is large, a large amount of force is required to be applied to the foot pedal by the caregiver to lift the pair of caster wheels off the floor surface. This can result in the caregiver failing to fully actuate the auxiliary wheel assembly, e.g., false deployments, and thus not experience the benefits of the auxiliary wheel assembly.
A patient transport apparatus designed to overcome one or more of the aforementioned challenges is desired.
Referring to
A support structure 12 provides support for the patient. The support structure 12 illustrated in
A mattress 24 is disposed on the patient support deck 20. The mattress 24 comprises a secondary patient support surface 26 upon which the patient is supported. The base 14, intermediate frame 16, patient support deck 20, and patient support surfaces 22, 26 each have a head end and a foot end corresponding to designated placement of the patient's head and feet on the patient transport apparatus 10. The construction of the support structure 12 may take on any known or conventional design, and is not limited to that specifically set forth above. In addition, the mattress 24 may be omitted in certain embodiments, such that the patient rests directly on the patient support surface 22.
Side rails 28, 30, 32, 34 are supported by the base 14. A first side rail 28 is positioned at a right head end of the intermediate frame 16. A second side rail 30 is positioned at a right foot end of the intermediate frame 16. A third side rail 32 is positioned at a left head end of the intermediate frame 16. A fourth side rail 34 is positioned at a left foot end of the intermediate frame 16. If the patient transport apparatus 10 is a stretcher, there may be fewer side rails. The side rails 28, 30, 32, 34 are movable between a raised position in which they block ingress and egress into and out of the patient transport apparatus 10 and a lowered position in which they are not an obstacle to such ingress and egress. The side rails 28, 30, 32, 34 may also be movable to one or more intermediate positions between the raised position and the lowered position. In still other configurations, the patient transport apparatus 10 may not comprise any side rails.
A headboard 36 and a footboard 38 are coupled to the intermediate frame 16. In other embodiments, when the headboard 36 and footboard 38 are provided, the headboard 36 and footboard 38 may be coupled to other locations on the patient transport apparatus 10, such as the base 14. In still other embodiments, the patient transport apparatus 10 does not comprise the headboard 36 and/or the footboard 38.
Caregiver interfaces 40, such as handles, are shown integrated into the footboard 38 and side rails 28, 30, 32, 34 to facilitate movement of the patient transport apparatus 10 over floor surfaces 41. Additional caregiver interfaces 40 may be integrated into the headboard 36 and/or other components of the patient transport apparatus 10. The caregiver interfaces 40 are graspable by the caregiver to manipulate the patient transport apparatus 10 for movement.
Other forms of the caregiver interface 40 are also contemplated. The caregiver interface may comprise one or more handles coupled to the intermediate frame 16. The caregiver interface may simply be a surface on the patient transport apparatus 10 upon which the caregiver logically applies force to cause movement of the patient transport apparatus 10 in one or more directions, also referred to as a push location. This may comprise one or more surfaces on the intermediate frame 16 or base 14 This could also comprise one or more surfaces on or adjacent to the headboard 36, footboard 38, and/or side rails 28, 30, 32, 34. In other embodiments, the caregiver interface may comprise separate handles for each hand of the caregiver. For example, the caregiver interface may comprise two handles.
Support wheels 54 are coupled to the base 14 to support the base 14 on a floor surface such as a hospital floor. The support wheels 54 allow the patient transport apparatus 10 to move in any direction along the floor surface 41 by swiveling to assume a trailing orientation relative to a desired direction of movement. In the embodiment shown, the support wheels 54 comprise four support wheels each arranged in corners of the base 14. The support wheels 54 shown are caster wheels able to rotate and swivel about swivel axes 56 during transport. Each of the support wheels 54 forms part of a caster assembly 58. Each caster assembly 58 is mounted to the base 14. It should be understood that various configurations of the caster assemblies 58 are contemplated. In addition, in some embodiments, the support wheels 54 are not caster wheels and may be non-steerable, steerable, non-powered, powered, or combinations thereof. Additional support wheels 54 are also contemplated.
An auxiliary wheel assembly 60 is coupled to the base 14. The auxiliary wheel assembly 60 influences motion of the patient transport apparatus 10 during transportation over the floor surface 41. The auxiliary wheel assembly 60 comprises a pair of auxiliary wheels 62 and an actuator system 66 operatively coupled to the auxiliary wheels 62. The actuator system 66 is operable to move the auxiliary wheels 62 between various deployed positions in contact with the floor surface 41 and a stowed position spaced away and out of contact with the floor surface 41.
By deploying the auxiliary wheels 62 on the floor surface 41, the patient transport apparatus 10 can be easily moved down long, straight hallways or around corners, owing to a non-swiveling nature of the auxiliary wheels 62. When the auxiliary wheels 62 are stowed (see
The auxiliary wheels 62 may be arranged parallel to each other and the longitudinal axis 18 of the base 14. Said differently, the auxiliary wheels 62 rotate about a rotational axis R oriented perpendicularly to the longitudinal axis 18 of the base 14 (albeit offset in some cases from the longitudinal axis 18). In the embodiment shown, the auxiliary wheels 62 are incapable of swiveling about a swivel axis and are non-driven, and are also referred to as steer wheels. In other embodiments, the auxiliary wheels 62 may be capable of swiveling, but can be locked in a steer lock position in which they are locked to solely rotate about the rotational axis R oriented perpendicularly to the longitudinal axis 18. In still other embodiments, the auxiliary wheels 62 may be able to freely swivel without any steer lock functionality. In embodiments in which the auxiliary wheels 62 are able to swivel, they may swivel about their own, separate swivel axes, or a common swivel axis of the auxiliary wheel assembly 60. The auxiliary wheel assembly 60 may comprise one, two, or more auxiliary wheels 62.
The auxiliary wheels 62 may be located to be deployed inside a perimeter of the base 14 and/or within a support wheel perimeter 64 defined by the swivel axes 56 of the support wheels 54. In some embodiments, such as those employing a single auxiliary wheel 62, the auxiliary wheel 62 may be located near a center of the support wheel perimeter 64, or offset from the center. In this case, the auxiliary wheel 62 may also be referred to as a fifth wheel. The auxiliary wheels 62 may be longitudinally and equally offset from the center of the support wheel perimeter 64. The auxiliary wheels 62 may also be equally and oppositely offset from the longitudinal axis 18 to be symmetrically positioned with respect to the longitudinal axis 18. In other embodiments, the auxiliary wheels 62 may be disposed along the support wheel perimeter 64 or outside of the support wheel perimeter 64. In the embodiment shown, each of the auxiliary wheels 62 has a diameter larger than a diameter of the support wheels 54. In other embodiments, the auxiliary wheels 62 may have the same or a smaller diameter than the support wheels 54.
Referring to
In the embodiment shown in
The second actuation device 66b operates to move the auxiliary wheels 62 relative to the base 14 from the first deployed position to a second deployed position (
In the first deployed position (
The first actuation device 66a has a first housing 67a pivotally coupled to the base 14. More specifically, an actuator support structure 69 extends across the base 14 to support the first housing 67a. The actuator support structure 69 comprises a pair of support arms 71 (see
The second actuation device 66b has a second housing 67b fixed to the first drive rod 75a such that linear movement of the first drive rod 75a causes linear movement of the second housing 67b. The second actuation device 66b further comprises a second drive rod 75b connected to a piston that is driven by the second actuation device 66b to extend and retract with respect to the second housing 67b. Movement of the second drive rod 75b relative to the second housing 67b varies the deployment of the auxiliary wheels 62 by virtue of further pivoting the axle 65 relative to the first cross member 61 to raise and lower the axle 65.
It should be appreciated that many other configurations of the patient transport apparatus 10 and the auxiliary wheel assembly 60 are possible for controlling deployment of the auxiliary wheels 62. For instance, the actuation devices 66a, 66b are arranged in series in
The first and second actuation devices 66a, 66b may operate simultaneously or sequentially to move the auxiliary wheels 62 from the stowed position, to the first deployed position, and then to the second deployed position. The first and second actuation devices 66a, 66b may be completely independent and able to operate and function separately from one another. In other cases, the first and second actuation devices 66a, 66b may provide distinct movements of the auxiliary wheels 62, yet be integrated into a single assembly, or can be formed into separate assemblies. In some cases, the first actuation device 66a moves the auxiliary wheels 62 a first distance relative to the base 14 and the second actuation device 66b moves the auxiliary wheels 62 a second distance relative to the base 14, with the first distance being greater than the second distance.
Referring to
In the first stage, illustrated as movement from
The actuator system 66 is configured in one embodiment to sequence operation of the actuation devices 66a, 66b such that the first actuation device 66a is initially operated to move the auxiliary wheels 62 from the stowed position to the first deployed position, and upon the auxiliary wheels 62 reaching the first deployed position, the second actuation device 66b is operated to move the auxiliary wheels 62 from the first deployed position to the second deployed position. In some cases, the transition from the first stage to the second stage is automatic such that no user intervention is required. For example, the automatic transition may be based on sensed loads, pressure, position, and the like. Furthermore, the first actuation device 66a may be configured to move the auxiliary wheels 62 in the first stage at a first actuation rate and the second actuation device 66b may be configured to move the auxiliary wheels 62 in the second stage at a second actuation rate, slower than the first actuation rate. As a result, the user can quickly move the auxiliary wheels 62 from the stowed position to the first deployed position to quickly start moving the patient transport apparatus 10 down a hallway, but additional deployment to the second deployed position may occur slowly, such as while the patient transport apparatus 10 is being moved.
The foot pedal 82 is configured to receive an applied force from the user and transmit the applied force into the actuator system 66 to move the auxiliary wheels 62 from the stowed position to the first deployed position, and further to the second deployed position. The first actuation device 66a is configured so that a first force is required to be applied by the user to the foot pedal 82 to move the auxiliary wheels 62 from the stowed position to the first deployed position and the second actuation device 66b is configured so that a second force is required to be applied by the user to the foot pedal 82 to move the auxiliary wheels 62 from the first deployed position to the second deployed position. In some cases, the first force is substantially the same as the second force, or within 5, 10, 15, or 20% of the second force. The force may be defined as the force applied perpendicular to the lever arm created by the foot pedal 82. The first and second forces may be applied by the user in noticeably discrete motions (e.g., foot presses). In other words, there may be a noticeable transition between a first foot press in which the user applies the first force to depress the foot pedal 82 so that the auxiliary wheels 62 move from the stowed position to the first deployed position and a second foot press in which the user applies the second force to depress the foot pedal 82 so that the auxiliary wheels 62 move from the first deployed position to the second deployed position. This transition may be a subtle increase (or decrease) in the force required to be applied by the user to continue moving the foot pedal 82 or may result from an integrated feedback device (e.g., audible feedback, visual feedback, or other form of haptic feedback). Additionally, or alternatively, the actuation devices 66a, 66b may be configured so that the force required to be applied by the user to move the auxiliary wheels 62 from the stowed position to the first deployed position and further to the second deployed position remains substantially constant throughout an entire range of movement of the foot pedal 82 so that such a transition is less discernable by the user.
Referring to
The hydraulic circuit 100 further comprises a spring-operated check valve 106 to control flow of the hydraulic fluid during movement of the foot pedal 82 and to maintain pressure in the hydraulic circuit 100. When the user begins depressing the foot pedal 82, such as from the neutral position (also referred to as a disengaged state/position) to the first stage (also referred to as an engaged state/position), pumping begins and hydraulic fluid is moved through the spring-operated check valve 106 to the first actuation device 66a to cause displacement of the first drive rod 75a relative to the first housing 67a. As described below, a biasing device 124 (see
A pressure activated switch 108 is reactive to such changes in the pressure. The pressure activated switch 108 may be incorporated into the pump 102 or may be separate in the hydraulic circuit 100. The pressure activated switch 108 is configured to selectively divert hydraulic fluid to the first or second actuation devices 66a, 66b. When the pressure has reached a threshold, the switch 108 is automatically activated to divert hydraulic fluid from the first actuation device 66a to the second actuation device 66b. Thus, during operation, when the auxiliary wheels 62 reach the floor surface 41 such that additional load is now acting on the first actuation device 66a, the pressure in the hydraulic circuit 100 increases and the pressure activated switch 108 reacts by diverting the hydraulic fluid to the second actuation device 66b. The second actuation device 66b is designed to accommodate the additional load, as described below, and in some cases without requiring a substantial change in the amount of force to be applied by the user on the foot pedal 82. More specifically, in some cases, once the switch is activated to divert hydraulic fluid flow, the pressure is reduced owing to the second actuation device 66b having a different configuration than the first actuation device 66a. Once the hydraulic fluid is diverted to the second actuation device 66b, the drive rod 75b of the second actuation device 66b is thereafter displaced until a predefined distance is reached, until the end of its stroke, or otherwise.
In the embodiment shown in
As previously mentioned, the first and second actuation devices 66a, 66b may be configured so that the user is able to apply a consistent force on the foot pedal 82 to cause the hydraulic fluid to move the auxiliary wheels 62 from the stowed position to the first deployed position, and then to the second deployed position, even though the loads acting on the first and second actuation devices 66a, 66b may be substantially different. This can be accomplished by sizing the first and second actuation devices 66a, 66b appropriately. For example, if the load acting on the second actuation device 66b is ten times larger than the load acting on the first actuation device 66a, then the surface area of the piston connected to the second drive rod 75b could be sized ten times larger than the surface area of the piston connected to the first drive rod 75a. As a result, for instance, if the pump 102 is a simple piston pump, then the same force applied by the user to the foot pedal 82 would operate both the first actuation device 66a and the second actuation device 66b (e.g., the same pressure would be present in the hydraulic circuit 100 in both the first stage and the second stage). At the same time, in this example, for the same displacement of the foot pedal 82, the second drive rod 75b would move in the second stage one tenth of the movement of the first drive rod 75a in the first stage.
In some cases, the first actuation device 66a is configured so that the first force required to be applied by the user to the foot pedal 82 to move the auxiliary wheels 62 from the stowed position to the first deployed position is less than the second force required to be applied by the user to the foot pedal 82 to move the auxiliary wheels 62 from the first deployed position to the second deployed position. For example, as previously discussed, a slight increase in the force being applied may be desirable to provide the user with tactile feedback indicating a transition between the first stage and the second stage so that the user is aware that the pair of support wheels 54 are being lifted off the floor surface 41.
A release valve 118 is present in the hydraulic circuit 100 to selectively control flow of the hydraulic fluid from the actuation devices 66a, 66b back to the reservoir 104. The release valve 118 is operatively coupled to the foot pedal 82 (or other input device). More specifically, in the embodiment shown, a mechanical linkage 115 couples the foot pedal 82 to the release valve 118 to selectively open or close the release valve 118 when the foot pedal 82 is moved. In other embodiments, a second hydraulic pump could be used to open or close the release valve 118. The release valve 118 opens fluid communication between the actuation devices 66a, 66b and the reservoir 104 upon movement of the foot pedal 82 back to the neutral position.
The release valve 118 may comprise a flow restrictor, check valve, or other components necessary to control/limit the flow of the hydraulic fluid. In some cases, a simple control valve may be employed to open/close fluid flow. In the embodiment shown, the release valve 118 comprises a variable orifice 120 that operates to control and restrict the flow of the hydraulic fluid back to the reservoir 104 once released. This controlled release acts to dampen the flow of the hydraulic fluid and thus avoid abrupt drops of the support wheels 54 that are raised off the floor surface 41 that would otherwise occur owing to the weight of the patient transport apparatus 10 acting on the auxiliary wheels 62.
When the release valve 118 is opened, the auxiliary wheels 62 move from the second deployed position to the first deployed position under the weight of the patient and/or the other components of the patient transport apparatus 10 being supported by the auxiliary wheels 62. More specifically, when the release valve 118 is opened, pressure in the hydraulic circuit 100 between the first and the second actuation devices 66a, 66b and the release valve 118 is released causing hydraulic fluid to flow from the first and the second actuation devices 66a, 66b to the release valve 118 and through the orifice 120 (the pressure activated switch 108 also resets to its original position). A stowing device, such as the biasing device 124 (see
A hydraulic accumulator 109 may be in fluid communication with the second actuation device 66b in the hydraulic circuit 100 to provide suspension during transport of the patient on the patient transport apparatus 10. In other versions, the hydraulic accumulator 109 is absent.
A locking device 110 may be used to lock the auxiliary wheels 62 in the second deployed position when the foot pedal 82 is at the second stage (see
As the foot pedal 82 moves from the first stage to the second stage, the foot pedal 82 engages a camming surface of the locking element 112 and pivots the locking element 112 against the bias of the biasing device 114 until the foot pedal 82 passes under a catch of the locking element 112. Thereafter, the locking element 112 is biased into the locked state to hold the foot pedal 82 in the second stage. The foot pedal 82 may also be separately biased by a biasing device (e.g., a second torsion spring) that biases the foot pedal 82 toward the neutral, disengaged position. A release pedal 116 is fixed to the locking element 112 to release the locking element 112 upon actuation by the user. Other suitable locking devices 110 are also contemplated and may be integrated into other components, such as the pump 102, actuation devices 66a, 66b, or the like.
Referring to
In this embodiment, the control system 80 comprises a controller 200 having one or more microprocessors for processing instructions or for processing algorithms stored in memory to control operation of the second actuation device 66b and/or other powered devices. Additionally or alternatively, the controller 200 may comprise one or more microcontrollers, field programmable gate arrays, systems on a chip, discrete circuitry, and/or other suitable hardware, software, or firmware that is capable of carrying out the functions described herein. The memory may further store one or more look-up tables that define control parameters of the second actuation device 66b and other powered devices. The controller 200 may be carried on-board the patient transport apparatus 10, or may be remotely located. In one embodiment, the controller 200 is mounted to the base 14.
A generator 202 and energy storage device 204 (e.g., battery, capacitor, etc.) provides power for the second actuation device 66b and the controller 200. The generator 202 and the energy storage device 204 are coupled to the controller 200. The generator 202 is operatively coupled to one or more of the auxiliary wheels 62 to generate electricity in response to rotation of the auxiliary wheels 62. For instance, after the first actuation device 66a (e.g., the first hydraulic actuator) moves the auxiliary wheels 62 from the stowed position to the first deployed position in the same manner as previously described, the auxiliary wheels 62 contact the floor surface 41. By virtue of being in contact with the floor surface 41, the auxiliary wheels 62 are able to rotate when the user begins to move the patient transport apparatus 10. As the auxiliary wheels 62 rotate, electricity is being generated and stored in the energy storage device 204. See, for example, U.S. patent application Ser. No. 16/168,089, filed Oct. 23, 2018, entitled, “Techniques For Power Transfer Through Wheels Of A Patient Support Apparatus,” and U.S. patent application Ser. No. 16/168,212, filed Oct. 23, 2018, entitled, “Energy Harvesting And Propulsion Assistance Techniques For A Patient Support Apparatus,” both of which describe the use of wheels in generating and storing energy for patient transport apparatuses, the disclosures of both are hereby incorporated herein by reference.
At the same time that energy is being stored, portions of the energy is being used by the controller 200 to actuate the second actuation device 66b. The controller 200 is coupled to the second actuation device 66b in a manner that allows the controller 200 to control the second actuation device 66b. The controller 200 may communicate with the second actuation device 66b via wired or wireless connections. The controller 200 generates and transmits control signals to the second actuation device 66b, or components thereof, to cause the second actuation device 66b to perform one of more desired movements or functions. The controller 200 may monitor an actual state of the second actuation device 66b and determine desired states to which the second actuation device 66b should be placed, based on one or more input signals that the controller 200 receives from one or more input devices. The state of the second actuation device 66b may be a position, a relative position, a speed, a force, a load, a current, an energization status (e.g., on/off), or any other parameter of the second actuation device 66b. The input devices used to control operation of the second actuation device 66b comprises user input devices, such as the foot pedal 82 and/or one or more sensors S in communication with (e.g., coupled to) the controller 200. The sensors S may be position sensors, such as potentiometers, encoders, hall-effect sensors, accelerometers, and the like.
In this embodiment, instead of the user providing the applied forces on the foot pedal 82 required to move the auxiliary wheels 62 from the stowed position (against the biasing device 124) to the first deployed position, and further to the second deployed position, the user is only required to move the foot pedal to the first stage (in this embodiment the locking device 110 locks the foot pedal 82 after movement to the first stage as shown). The controller 200 handles the second stage automatically. In the embodiment shown, the sensor S detects rotation of the foot pedal 82 to the first stage. The controller 200 receives the corresponding signal from the sensor S that then causes the second actuation device 66b, e.g., the electric linear actuator, to operate and further move the auxiliary wheels 62 to the second deployed position.
This movement to the second deployed position could occur over a predetermined period of time, e.g., 5, 10, 15, 20, 60, 120 seconds, or less. This movement could also begin immediately after the foot pedal 82 has been moved to the first stage, or could be delayed for a predetermined period of time, e.g., 5, 10, 15, 20, 60, 120 seconds, or less. Movement of the auxiliary wheels 62 from the first deployed position to the second deployed position may also be triggered by and/or occur during rolling of the auxiliary wheels 62, which can be detected based on whether the generator 202 is generating electricity or via an accelerometer or other movement sensor. Once the second deployed position is reached, the controller 200 discontinues operation of the second actuation device 66b.
Other mechanisms are also contemplated that move the auxiliary wheels 62 from the first deployed position to the second deployed position in response to rolling of the auxiliary wheels 62 along the surface whereby rolling of the auxiliary wheels 62 along the surface generates energy at least partially used by the actuator system 66 to move the auxiliary wheels 62 from the first deployed position to the second deployed position.
In another embodiment, three actuation devices may be employed. The first and second actuation devices 66a, 66b may comprise the combination of the first and second hydraulic actuators as previously described and the third actuation device comprises the electrically powered actuator as previously described. In this embodiment, the first and second actuation devices 66a, 66b operate in the same manner described, but to a first deployed position in which the auxiliary wheels 62 are deployed such that the pair of support wheels 54 are lifted only slightly off the floor surface 41, such as from 0.01 to 0.10 inches off the floor surface 41, i.e., the auxiliary wheels 62 are not fully deployed. Again, the user depresses the foot pedal 82 to actuate the first and second actuation devices 66a, 66b to only slightly lift the pair of support wheels 54 off the floor surface. The third actuation device then operates automatically in the same manner described above to further move the auxiliary wheels to the second deployed position. By having the user actuate the foot pedal 82 to at least slightly lift the pair of support wheels 54 off the floor surface 41, then the auxiliary wheels 62 may make better contact with the floor surface 41 and provide better maneuverability of the patient transport apparatus 10 than if the auxiliary wheels 62 only make initial contact with the floor surface 41, but without substantially increasing the amount of work required to be input by the user (and without additional time spent by the user to further deploy the auxiliary wheels 62)—the third actuation device automatically provides the additional work required to move the auxiliary wheels 62 to the fully deployed position.
It is to be appreciated that the terms “include,” “includes,” and “including” have the same meaning as the terms “comprise,” “comprises,” and “comprising.”
Several embodiments have been discussed in the foregoing description. However, the embodiments discussed herein are not intended to be exhaustive or limit the invention to any particular form. The terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations are possible in light of the above teachings and the invention may be practiced otherwise than as specifically described.
This application is a Continuation of U.S. patent application Ser. No. 16/204,100, filed on Nov. 29, 2018, which claims priority to and the benefit of U.S. Provisional Patent Application No. 62/592,940, filed on Nov. 30, 2017, the disclosures of each of which are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62592940 | Nov 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16204100 | Nov 2018 | US |
| Child | 17460650 | US |
