Patent Application
20180214330
The invention relates generally to devices, apparatuses, systems and methods for patient transfer. More specifically, the invention relates to patient transfer from a rollable powered wheelchair to a bed and back.
Transferring a person with a disability (PwD) between a bed and a wheelchair—or standing position, commode, chair, walker, and/or toilet—can be a labor intensive and time consuming task. In some cases, it can take multiple people to perform the transfer and can cause injury (both acute and cumulative) to the PwD, the caregiver, and/or the transfer equipment, particularly if errors are made during transfer (e.g., if the chair is mis-positioned or the brakes are not engaged). Other risks of PwD transfer include fear, loss of dignity, and increased dependence on others.
For PwDs who need assistance with transfers, there are not a lot of good options. The most commonly used lift technologies include the overhead ceiling lift, the floor-based sling lift, and the Gantry lift. While these devices allow for safer transfer of PwDs, they do so with shortcomings. For example, overhead sling lifts require extensive installation that may not be suitable for homes or buildings with structural deficiencies or low ceilings; floor-based sling lifts have issues with caregiver manipulation and ease of use; and gantry lifts are difficult to move and store due to their size.
Research and experience suggest that caregivers and PwDs are unsatisfied with current patient transfer technology, and are concerned that their lifestyle is impaired by the lack of appropriate technologies or that it will negatively affect them and their caregivers in their futures. Typically, wheelchairs and beds have been regarded as separate technologies, with the designers of one technology not working in tandem with designers of the other to coordinate movement between the two. What is needed is a solution that makes patient transfer more streamlined, convenient, and safe, both for the patient and the caregivers involved.
The present invention includes improved systems and methods for patient transfer, such as enabling autonomous transfers of an occupant of a rollable chair (e.g., a powered wheel chair or “PWC”) to and from a bed. In some embodiments, the invention includes a powered, pedestal-mount wheelchair that works in tandem with a hospital bed having a built-in conveyor. In some embodiments, the invention provides powered, coordinated and synchronized motion of the wheelchair seat and the bed to allow for independent transfers from one to the other while minimizing the physical effort needed by the patient and/or the caregiver(s) during transfer. In some embodiments, the invention includes a new transfer device for users of electric powered wheelchairs (“EPWs”) that is designed to reduce environmental and equipment complications that can lead to progressive inactivity of persons with disabilities, as well as frustration and injury risks experienced by users and their assistants. In some embodiments, the invention automates EPW-to-bed transfers, saving time, minimizing staff involvement, and decreasing caregiver risk.
In some embodiments, the seat frame of the chair travels rearward and rotates to move the seated occupant onto or proximal to the foot end of the bed. For context, in certain prior manual chair configurations, these motions have been handled with separate frames (a sliding frame and a rotating seat frame) and were separately powered by actuators in a docking module of the bed. In the present invention, these motions can be produced by a single seat frame powered by just one actuator. For example, the seat frame can be drawn along a “J”-shaped path or track. In some embodiments, the actuator initially draws a rearward edge of the seat frame horizontally along a straight section of the track. This movement begins to position the occupant proximal to the moving bed conveyor by closing the gap between the seat frame and the bed. Once in position for transfer, the powered wheelchair backrest rotates or translates laterally and the PwD leans against the mattress of the bed, which has been positioned near vertically. The actuator continues to draw the rear edge of the seat frame down along the arced path, causing the front edge of the seat frame to tip upward toward the bed, further pushing and/or lifting the occupant's legs up onto the moving bed conveyor. The bed rotates synchronously as the conveyor moves to minimize shear by matching the kinematics and rate of motion.
In some embodiments, the chair has a leg ramp with a foot rest that is hinged at the front edge of the seat frame, and linkage connecting the leg ramp to the seat frame can control the angle between the two. In some embodiments, the nominal angle is potentially adjustable to allow an elevated position to support the occupant's legs while the chair is in the “normal” position. The linkage can control and synchronize the angle of the ramp/leg rest to minimize shear forces on the occupant's legs during transfers and when the chair is in the “tilt” position. The linkage can also control leg ramp position without the need for another actuator.
In some embodiments, a powered back helps to enable autonomous or independent transfers. The powered back can be configurable, for example, to rotate or slide to the left or right and can be field-adjustable. The system can control the point in the transfer when the back unlocks and pivots out from behind the chair occupant. Sensors can ensure correct back position and locking. Motor current may be monitored to detect collisions of the back into objects or to cause a prompt to the occupant to lean forward off the chair back. An armrest opposite the side of the back that pivots can be moved out of the way by the occupant. In some embodiments, sensing of this position and powered locking may be used.
In some embodiments, actuators and mechanisms for seat and back frames occupy space to the rear and sides of the chair, leaving the volume directly under the seat relatively open. This arrangement can provide a single, centered mounting point that fits to a post of the PWC. In some embodiments, this design can be adapted to pedestal-mount chairs from several manufacturers. In some embodiments, the design can be revised to work with wheelchairs with base designs other than the pedestal-mount designs. In some embodiments, as the chair translates for transfer the seat frame tilts backward. This feature can provide a powered tilt option. In this mode the chair back can be left locked in place and rearward translation can provide an adjustable amount of tilt. In some embodiments, movement of the chair back can be limited, e.g., to prevent a center of gravity from moving to an unstable point or tipping point.
In some embodiments, the chair connects to and communicates with the bed electronically, e.g., by umbilical cable or wirelessly. The actuators in the chair may be powered directly from the bed if connected by umbilical or from the chair's own controller or power supply. Whether powered from the bed or self-powered, command of chair movements and/or actuators can be controlled and coordinated by a controller (located, e.g., in the bed, or anywhere within wireless communication range if connected wirelessly). In some embodiments, the motions of both can be synchronized for safe and comfortable transfers. In some embodiments, both the chair and the bed can have absolute sensing of actuators positions, speed and current draw, and separate IO to ensure correct frame positions and frame locking. In some embodiments, chair and bed use actions are logged by the bed and stored electronically.
In some embodiments, the chair is positioned at the foot of the bed (and/or couples to the bed, e.g., mechanically and/or electronically) for transfer. One approach is to use a docking assembly or docking platform. In such embodiments, an operator can drive the chair up onto the docking platform from almost any angle within a ground plane. In some embodiments, the docking assembly can sense the approach angle of the chair and rotate or otherwise move to align with it. Once the chair is properly positioned on the platform, the docking assembly can rotate the chair to be square to the foot end of the bed and draw a platform back for transfer. Command of the docking assembly can reside, e.g., in the bed controller. In some embodiments, the chair positions itself using a drive system. In some embodiments, the docking assembly includes electronic docking options based on user ability.
In some embodiments, the rollable chair is an EPW and/or a Group-2 wheelchair. In some embodiments, the patient transfer system allows a patient to transfer from the chair to the bed and back with minimal or no assistance from a caregiver. In some embodiments, the movements of the bed and custom wheelchair seating system are electrically powered and synchronized through computer control. In some embodiments, the patient transfer system is particularly suitable for patients with a primary diagnosis of obesity, cardiovascular disease, cardiopulmonary disease, paraplegia with upper extremity pain or overuse injury, or metabolic diseases, at least because they often use powered wheelchairs and have the ability to operate their powered wheelchair and to control the interface for the transfer device.
In one aspect, the invention features a rollable chair. The rollable chair includes a first frame including a seat. The rollable chair also includes a second frame coupled to the first frame, the second frame including a backrest configured to move relative to the first frame. The rollable chair also includes a third frame coupled to the first frame, the third frame including a track having a curvilinear length configured to allow the first frame to rotate and/or to translate relative to the third frame.
In some embodiments, the track further includes a linear length configured to allow the first frame to translate relative to the third frame, the linear length adjoining the curvilinear length. In some embodiments, the track includes a J-shape. In some embodiments, the first frame is powered by a first actuator that is mechanically coupled to the first frame. In some embodiments, the rollable chair includes at least one sensor, connected to the rollable chair, for determining a position of the rollable chair relative to a bed. In some embodiments, the second frame is configured to rotate about a pivot point to permit the backrest to be removed from a path of patient transfer between the rollable chair and a bed. In some embodiments, the second frame is powered by a second actuator that is mechanically coupled to the second frame.
In some embodiments, the second frame includes a latching mechanism configured to engage with a corresponding latching mechanism of the third frame. In some embodiments, the corresponding latching mechanism on the third frame includes a taper configured to proper alignment of the rollable chair. In some embodiments, the rollable chair includes a quick-release feature for aiding an assistant with disengaging the rollable chair from a bed. In some embodiments, the rollable chair further includes a fourth frame that is mechanically coupled to the first frame, the fourth frame including a leg rest. In some embodiments, the first and fourth frames are rigidly coupled, the fourth frame configured to guide a patient's legs during a patient transfer operation. In some embodiments, the rollable chair is configured to couple to a bed having a chair receiving frame. In some embodiments, the seat has a posterior tilt with respect to the rollable chair.
In another aspect, the invention includes a patient transfer system. The patient transfer system includes a rollable chair having a first frame including a seat; a second frame coupled to the first frame, the second frame including a backrest configured to move relative to the first frame; and a third frame coupled to the first frame, the third frame including a track having a curvilinear length configured to allow the first frame to rotate and/or to translate relative to the third frame. The patient transfer system also includes a bed including a chair receiving frame configured to couple to the first frame of the rollable chair.
In some embodiments, the patient transfer system further includes a first microprocessor coupled to the rollable chair and a second microprocessor coupled to the bed, the first microprocessor in direct or indirect electronic communication with the second microprocessor. In some embodiments, the patient transfer system further includes a computing device in electronic communication with the first and second microprocessors, the computing device configured to execute instructions to coordinate kinematics between the rollable chair and the bed during a patient transfer operation. In some embodiments, a motion path of the seat is determined by the computing device and includes both translational and rotational components.
In some embodiments, the bed is configured to fold during a patient transfer operation between the rollable chair and the bed, the bed configured to work in tandem with the rollable chair to receive the patient during a patient transfer operation. In some embodiments, the patient transfer system further includes a docking assembly configured to receive the rollable chair and to facilitate transfer of a patient from the rollable chair to the bed. In some embodiments, the docking assembly is configured to receive the rollable chair from any (or nearly any) angle of approach within a ground plane. In some embodiments, the docking assembly includes a third microprocessor, the third microprocessor in direct or indirect electronic communication with the first and second microprocessors. In some embodiments, the bed includes a sensor configured to ensure that the rollable chair is properly positioned with respect to the bed. In some embodiments, the rollable chair is a retrofitted Group 2 Electric Powered Wheelchair.
In another aspect, the invention features a method of transferring a patient between a rollable chair and a bed. The method includes positioning the rollable chair at or near a proximal end of the bed. The method also includes translating a distal end of the bed toward the proximal end of the bed, the bed folding into a first section and a second section, wherein the first section becomes positioned behind a chair back of the rollable chair and the second section forms an angle with the first section. The method also includes moving the chair back of the rollable chair, via at least one of a rotational or a translational motion, such that the patient contacts the first section of the bed. The method also includes moving a seat frame of the rollable chair along a guide rail disposed relative to the seat frame, via at least one of a translational or a rotational motion, to position the patient at least substantially on the bed.
In some embodiments, the guide rail is a track having a curvilinear length. In some embodiments, moving the chair back is accomplished using a powered actuator. In some embodiments, moving the seat frame is coordinated with a simultaneous or near-simultaneous moving of the bed. In some embodiments, positioning the rollable chair at or near a proximal end of the bed is achieved using a docking assembly positioned proximate the bed and the rollable chair.
The first frame 112 includes a seat 124, which can be a square cushion capable of supporting a patient. The seat 124 can assume a posterior tilt with respect to the rollable chair 104 during a patient transfer operation, as shown and described in greater detail below. The second frame 116 includes a backrest 128, which can include a section of canvas, cloth, or another material capable of supporting a patient's back and/or matching the size and medical needs of the user. The backrest 128 can be configured to move relative to the first frame 112, e.g., to rotate about a pivot point or to translate, such that the backrest 128 is removable from a patient transfer path between the rollable chair 104 and the bed 108 during a patient transfer operation. For example, in
The third frame 120 includes a track 148 (e.g., having a curvilinear length 148A) configured to allow the first frame 112 to rotate and to translate relative to the third frame 120, for example, during a patient transfer operation as shown and described in greater detail below. In some embodiments (e.g., as shown in
The bed 108 includes a first frame 132 (e.g., a main frame), a second frame 136 (e.g., a chair receiving frame), and a third frame 140 (e.g., a movable frame). The first frame 132 includes wheels (e.g., wheels 134A, 134B). The second frame 136 interfaces with sensors of the rollable chair 104 (as shown and described below). The third frame 140 includes a mattress 144 and can be powered by a bed actuator. The bed 108 (e.g., the mattress 144) is configured to fold during a patient transfer operation between the rollable chair 104 and the bed 108, the bed 108 configured to work in tandem with the rollable chair 104 to receive the patient during a patient transfer operation. The bed has a proximal end 154A (e.g., a foot end) and a distal end 154B (e.g., a head end), the distal end 154B configured to translate toward the proximal end 154A during a patient transfer operation.
In some embodiments, the rollable chair 104 includes a fourth frame 156 that is mechanically coupled to the first frame 112. In some embodiments, the fourth frame 156 includes a leg rest 160 (e.g., is rigidly coupled to the leg rest 160). In some embodiments, the leg rest 160 includes two separate shoe prints 162A, 162B for separately accommodating a patient's two feet. In some embodiments, the leg rest 160 is made of molded plastic or another lightweight material suitable for supporting a patient's feet. In some embodiments, the fourth frame 156 is configured to guide a patient's legs during a patient transfer operation (e.g., as shown and described below in
In some embodiments, the patient transfer system 100 includes a computing device 164 configured to execute instructions to coordinate movements between the rollable chair 104 and the bed 108 during a patient transfer operation. The computing device 164 can be in direct or indirect electronic communication with a first microprocessor 168 coupled to the rollable chair 104, and/or a second microprocessor 172 is coupled to the bed 108. In some embodiments, the computing device 164 is included the bed 108. In some embodiments, electronic communication is hard-wired and/or wireless. In some embodiments, the computing device 164 sends instructions to microprocessors 168, 172, which in turn trigger movements of first and second actuators and determine a motion path of the first frame 112 relative to the bed 108 (as shown and described in greater detail below). In some embodiments, a master/slave approach is used for the computing operations (e.g., as shown and described below in
Referring now to
In some embodiments, the docking assembly 300 has two degrees of freedom (e.g., a first degree including a linear dimension of fore and aft translation, and a second degree including rotation about the pivot feature 316). In some embodiments, the entire docking assembly 300 can roll or slide toward the bed 108 (or a top component of the docking assembly can roll or slide over the base). In some embodiments, the platform 304 can rotate 360 degrees and be accessible to the chair from any approaching direction. In some embodiments, the docking assembly 300 is short enough in height to be able to fit under the bed when it is not in use, e.g., about 50 millimeters.
In some embodiments, the docking assembly 300 is configured to receive the rollable chair from any angle of approach within a ground plane. For example,
Referring to
Referring to
With a back of the patient 436 now leaning against the first section 408C of the bed 408, referring now to
Meanwhile, referring to
In some embodiments, the patient transfer system 400 includes a user interface on a computing device that provides a series of verbal prompts during the course of operation. For example, the computing device can verbally prompt the operator (e.g., the patient or the caregiver) to remove sheets and blankets from the bed before beginning the transfer process. In some embodiments, after transferring the patient 436 to the bed, the bed automatically resets itself into a position to start the “to chair” transfer. In some embodiments, when ready to transfer back to the rollable chair 408, the conveyor sheet moves the patient 436 toward the foot end of the bed 408. As the patient's feet (or lower extremity) pass through the through-beam sensor at the foot end of the bed 408, software on the computing device can command the actuator controlling the first frame (e.g., seat rotation frame) to begin rotating as defined in the software parameters.
Once the seat is fully rotated, the head deck portion and foot deck portion of the bed frame are commanded by software on the computing device to rotate so that a foot deck portion of the mattress is moved to assist in moving the patient 436 into a seated position within the rollable chair 408. After the foot deck portion of the mattress has moved the person into the maximum seated position, the operator is prompted to activate the powered backrest into the locked upright position. After the backrest is locked in place, the seat translates and/or rotates away from the bed to further position the patient into a fully seated position. After the seat frame has translated forward to its maximum forward position, the operator is prompted to activate the rollable chair drive system, and the patient can drive the rollable chair 408.
In some embodiments, the timing and angle of chair movement is adjustable to accommodate height, weight and other attributes of individual patients. In some embodiments, the timing of the custom seat and bed functions are coordinated via software commands. In some embodiments, a transfer to or from a bed takes approximately two minutes. In some embodiments, there is an emergency pull switch that flattens the bed and cuts the power. In some embodiments, there is a battery backup that allows for five complete transfer cycles in two days.
In some embodiments, the conveyor sheet can be a 70 Denier Nylon, PVC coated material per IEC 60601 fire safety guidelines. In some embodiments, the conveyor sheet and can be 94″L×34″W×0.024″ H. In some embodiments, the conveyor sheet is very thin, e.g., if used with a pressure-relieving mattress, so as not to interfere with the goals of a such a mattress. In some embodiments, a fabric, 96″×35″, 60/40 poly/cotton bed sheet, is attached to the conveyer sheet with Velcro™ tabs and is used as the sleeping surface. The presence of the sheet does not need to interfere with the transfer into and out of the bed. The bed sheet can also be removed for regular washing as necessary. In some embodiments, the conveyor sheet remains in place and can be spot cleaned using disinfectant wipes. Periodic removal for more extensive cleaning and servicing is recommended and scheduled with the customer. Unless there is tearing or damage caused by misuse, the conveyor sheet can be replaced with a new or reconditioned sheet at the time of servicing. Changing the conveyor sheet can be a simple process, which takes approximately 15 minutes.
In some embodiments, when the patient transfer system 400 is active (input to the UI and/or system motion), every 100 ms a main controller (e.g., the computing device 164 shown and described above) communicates to a data logger the state of all electrical components (discrete input devices, motor currents/voltages, power supply input/output and batteries). In some embodiments, the data logger records these data to the USB memory device. For example, every 24 hours the data logger can write the day's data to a compressed file archive. In such embodiments, a 8 GB USB memory device can handle one day of continuous system operation and the archived data from the previous 30 days. In some embodiments, electronic components are located under the center of the bed.
In some embodiments, the invention incorporates an array of sensors to stop the operation of the patient transfer system if unsafe behavior is detected (e.g., clothing or parts of the body near moving parts, attempting to move the “patient” to far up the bed where they may hit the headboard). In some embodiments, the software prohibits moving from one step to the next without the sensors indicating that each step is completed. In some embodiments, the microprocessors are hardwired or wireless. In some embodiments, the microprocessors are in direct communication with one another or indirect communication, e.g., via a central processing hub.
In some embodiments, the bed interfaces with a Group 2 EPW equipped with a custom seating system. In some embodiments, the invention accommodates a wide variety of mattresses commonly used with hospital beds for acute care, long-term care, and homecare. In some embodiments, the bed incorporates one or more features of current “high-end” hospital beds, e.g., the ability to integrate several therapeutic pressure redistribution mattresses. In some embodiments, the custom wheelchair seating systems is compatible with a wide variety of seat cushions, such as foam, gel, air-flotation.
In some embodiments, the “J” track permits one continuous motion of the first frame along the third frame to provide seamless transfer of a patient from a rollable chair to a bed and back. In some embodiments, the track is mechanical or virtual (e.g., a set of actuators can be used to program the kinematics of motion that mimic a mechanical track). In some embodiments, a gap space 438 between patient and bed is minimized (e.g., minimized to a smallest practical length in view of competing constraints) at one or more points in the transfer, e.g., at the point shown in
The “Main Controller” then sends a signal to the “Seat Slide Motor Controller” to stop the “Seatback Actuator”, hence stopping the motion of the backrest. Completion of backrest removal initiates rotation of the seat (e.g., the seat 112 shown and described above) by the “Main Controller”. The “Main Controller” then sends a signal to the “Seat Rotate Motor Controller” telling it to turn on the “Seat Rotate Actuator”, which rotates the seat toward the bed. As the Seat rotates, the potentiometer sensor “Seat Rotate Position” sends signals to the “Main Controller” that state its current position. This information is used to coordinate the movements of the bed. When the seat physically contacts “SW11 Chair Rotate Present,” a signal is sent to the “Main Controller” indicating that seat has rotated to its maximum extent. The “Main Controller” sends a signal to the “Seat Rotate Motor Controller,” telling it to stop the motion of the “Seat Rotate Actuator”, which stops the rotation of the seat. The bed continues its own to position the person using the sheet and spool (not depicted), as in the manual chair product.
To return the patient to the rollable chair, the above steps can be executed substantially in reverse, with some exceptions. First, for the backrest striking the switch “Seatback Remove Limit Switch,” the “Seatback Restore Limit Switch” is physically contacted and port “OS2 Patient Bed Exit”, indicating the backrest is in its driving configuration. Second, for the seat physically contacting “SW11 Chair Rotate Present”, the motion of the seat rotation physically contacts the “SW10 Chair Rotate Latch” indicating the seat (112) is it drive position. The “Chair Connect Harness” is the physical connector that when connected tethers the bed wires to the wheelchair. “SW8 Chair Slide Latch” and “SW9 Chair Slide Latch” are legacy switches that are still physically present of the bed from the manual chair version but are not used in the power chair version.
While the invention has been particularly shown and described with reference to specific preferred embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the following claims.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/452,542 filed Jan. 31, 2017, entitled “Systems and Methods for Powered Wheelchair Personal Transfer,” the contents of which are hereby incorporated herein by reference in their entirety.
This invention was made with government support under Contract Nos. B9269-L and B9250C, awarded by the U.S. Dept. of Veterans Affairs, and Contract No. EEC-1560174S, awarded by the National Science Foundation. The U.S. Government may have certain rights in the invention.
| Number | Date | Country | |
|---|---|---|---|
| 62452542 | Jan 2017 | US |
