FOLDABLE AND NESTABLE WHEELCHAIR/CARRIER

Abstract: A nesting carrier/wheelchair is disclosed whereby the seat and the arm of the wheelchair can be lifted vertically upwards for storage. The base of the carrier/wheelchair is constructed in a manner which allows for nesting with other similar carrier/wheelchairs for compact storage. The construction also allows for sliding the carrier/wheelchair base under the patient's bed, in folded but self supporting position; while the medical equipment and attached accessories remain in the back of the frame. This allows for the usability of the carrier/wheelchair both in operating and storage position.

Description: FOLDABLE AND NESTABLE WHEELCHAIR/CARRIER Field Of The Invention The present invention relates to wheelchairs and in particular to a folding and nesting carrier and wheelchair especially adapted for use in the hospital environment. Background Of The Invention Commonly known wheelchairs are either of rigid construction or foldable for storage and transport. The two general types of foldable wheelchairs are laterally foldable and longitudinally or horizontally foldable respectively. Laterally foldable wheelchairs are disclosed in United States Patents No. 4,045,044; 4,431 ,206; 4,577,903; 4,598,921 ; 4,625,984; 4,696,420; 4,770,432; 4,861 ,059; 5,261 ,684; 5,340,140; and 5,634,650; while longitudinally or horizontally foldable wheelchairs are disclosed in United States Patents No. 636,582; 2,545,336; 4,280,716; 4,542,917; 4,639,012; 4,640,525; and 4,678,202 and Canadian Patent No. 830,267. The type of wheelchair most often used in hospitals is of a basic design developed in 1933 by Herbert Everest and Harry Jennings. That wheelchair folds laterally for transport and storage and includes a frame fabricated of tubular steel or aluminum and a leatherette seat and backrest. The chair is designed to be easily loaded into a car in the folded condition to travel with the user. A major current concern of hospitals is unauthorized removal of wheelchairs from hospital premises, since wheelchairs often travel with their users home from the hospital, only to never return. This results in significant capital losses to hospitals in view of the high replacement cost. Thus, wheelchairs with fixed frames would seem desirable. However, those require a large amount of storage space which is either unavailable in a hospital or too expensive. Consequently, a wheelchair is desired which cannot be easily loaded into a vehicle, but requires only a minimum of storage space. Storage is a concern because, although compact when folded, the conventional wheelchair serves no purpose in the folded mode. The longitudinally or horizontally foldable prior wheelchairs generally have foldable frames which means the wheeled supporting structure is folded as well making the chair highly unstable in the folded condition which is disadvantageous for storage. Again, the chair serves no purpose in the folded mode. Certain types of commonly known wheelchairs include a tray or carrier for patient support equipment such as crutches, surgical drainage bags, catheter bags, IV containers, patient monitoring apparatus, oxygen tanks, etc. as well as patient data sheets. Those carriers generally cannot be used in the folded condition of the wheelchair. Furthermore, when the patient is transferred to a hospital bed, medical equipment in the carrier is normally transferred from the chair to the patient's bedside and the chair physically removed from the bedside due to space constraints. In most instances, due to shortage of space, the wheelchair is not stored in close proximity to the patient. The whole process has to be repeated in reverse when the patient needs to use the chair, which is a drain on time and resources. Hygiene is another major concern with wheelchairs used in the hospital environment. Chairs are passed from patient to patient, contacting successive occupants. Institutional protocol may require the swabbing of chairs with a chlorine- based decontaminant. However, such treatment not only increases cost, but can also accelerate the failure of bearings and articulations of the chair. The construction material of the common wheelchair is not very conducive to proper cleaning. The following is a discussion of a number of patents selected from those listed above which are believed representative of the features of and problems associated with commonly known wheelchairs. Canadian Patent No. 830267, by Gardner and Wightman discloses a chair which is collapsable vertically downwards which allows for better propulsion and easier storage. However, in the folded condition, this chair is unstable and cannot support any equipment by the bedside. United States Patent No. 4,280,716 teaches a foldable wheel chair which is collapsible vertically by folding the supporting frame to bring the front and back wheels as close as possible to each other. The folded chair is unsuitable for bedside equipment support and is not conducive to easy storage in the collapsed state. United States Patent No. 2,713,893, by Kuhl discloses a wheelchair for supporting an iron lung. The chair construction does not allow for bedside use as equipment carrier. United States Patent Nos. 4,431 ,206 and 4,696,420 are both directed to carrying medical accessories on wheelchairs. Both patents teach accessory carriers for attachment to the back of a wheelchair which must be detached to permit folding of the chair. Both chairs are folded laterally and are not conducive for bedside equipment support in the folded condition. United States Patent No.2,545,336 is directed to a combination stroller and shopping carrier which has a rigid back and a collapsible seat structure. The chair would not function to support any equipment in the folded mode. United States Patent No. 4,640525 discloses a folding wheelchair assembly for dual use as wheelchair or flight attendant's seat onboard an aircraft. The frame and undercarriage are folded such that the chair is not self-supporting in the folded mode. Thus a wheelchair is desired which cannot be easily loaded into a car in the folded condition, requires relatively little storage space and is self-supporting in the folded condition, and preferably can efficiently support patient support equipment bedside. Summary Of The Invention The above identified problems encountered with prior art wheelchair constructions are now overcome with a nesting carrier and wheelchair in accordance with the invention. It is an object of the invention to provide a wheelchair with a rigid frame which cannot be easily loaded into a car but permits folding of the seat and armrests, if provided, and nesting with the frames of other identical wheelchairs for reduced space requirements during storage and cleaning or disinfection. It is another object of the invention to provide a wheelchair which is self-supporting in the folded condition. In a preferred embodiment, the wheelchair of the invention has a frame including an undercarriage or base portion that can be slid under a hospital bed, and an equipment support which remains functional in the folded condition of the wheelchair. These objects are achieved with a wheelchair comprising a rigid frame which consists of a base portion, and a support portion extending upward from the base in a substantially vertical orientation; the base being shaped and constructed for closely nesting with the base of another, identical wheelchair; means for movably supporting the base portion on a surface; a seat for supporting the weight of a person, the seat being movably connected with the frame for movement between an operating position wherein the person can sit on the seat, and a storage position wherein a seating surface of the seat is positioned substantially parallel to the support portion. Substantially vertical in this context means the support portion encloses an angle α with the horizontal of 70 to 90°. The parts of the wheelchair coming into contact with the user are preferably constructed from a moulded polymer for easy cleaning and disinfection. The wheelchair preferably further comprises armrests pivotally mounted to the frame for rotating between an operating position, wherein the arms of a person sitting on the seat can be supported; and a folded position wherein the armrests are positioned substantially parallel to the support portion to permit closer nesting with other, identical chairs and for facilitating the transfer of a patient into and out of the chair. In the preferred embodiment, the wheelchair further includes at least one of an IV pole, suitable for carrying IV liquid containers and metering pumps, a rack for medical oxygen tanks, a hook for a urine bag or other drainage bags, support for crutches or a stick, a pouch for medical records, and an articulated leg support. Brief Description Of The Drawings The preferred embodiment of the nesting wheelchair will now be described in detail with reference to the attached drawings. Figure 1 is a perspective view of the preferred embodiment of the wheelchair in accordance with the invention, including an IV pole; Figure 2 is a side elevational view of the wheelchair of Figure 1 with one armrest removed, the folded condition shown in broken lines, and shows another wheelchair nested therewith; Figure 3 is a top plan view of the wheelchair of Figure 1 ; Figure 4 is a perspective view of the wheelchair of Figure 1 , in the folded condition; Figure 5 is a rear perspective view of the wheelchair in Figure 1 , including an IV pole, a medical oxygen tank rack and a patient data pouch; Figure 6 illustrates the wheelchair in the folded condition, and adjacent to a patient's bed to function as equipment carrier; Figure 7 is a perspective view of the frame of the wheelchair shown in Figure 1 ; and Figure 8 is an exploded view of the armrest attachment mechanism. Detailed Description Of The Preferred Embodiment Referring to the Figures, the preferred embodiment of a nesting carrier and wheel chair in accordance with the invention includes a substantially L-shaped rigid frame 10 (see Fig. 7), a seat 14 (Figs. 1 and 2), a pair of armrests 15, a backrest panel 16 with equipment carrier 18 (Figs. 2 and 5) and a base cover or hood 19. The frame 10 (Fig. 7) is constructed of steel tubing and consists of an undercarriage or base portion 11 , and a substantially vertical support portion 12. The seat 14 is pivotally mounted to the support portion 12 to fold upwardly and rearwardly thereagainst. The backrest panel 16 is affixed to the support portion 12. Base cover 18 hides the base portion 11 of the frame 10 from view, while the backrest panel 16 hides the support portion 12 together with the equipment carrier 18 therebehind. Armrests 15 are also pivotally mounted to the support portion 12 to fold upwardly and rearwardly thereagainst. The frame 10 is principally made of two essentially L-shaped lateral frame sections 10a, 10b and front and top crossbars 10c, 10d (Fig. 7). Top crossbar 10d also functions as a handle 13 (Fig. 1) for the wheelchair. A center crossbar 10e is attached at its ends to the vertical portion of the lateral frame sections 10a, 10b, respectively by a pair of mounting brackets 10f. The center crossbar 10e also functions as the pivot axis for the seat 14 (Figs. 1 and 7). The lateral frame sections 10a, 10b are reinforced respectively by a gusset 10g. Four wheels 22 are attached to the undercarriage 11 of the frame at the four corners, to provide a means for movably supporting the base portion 11. The front wheels are caster wheels for directional manoeuvring; the two rear wheels are equipped with brakes 24 (Fig. 2) and the breaking of the chair in terms of keeping it from rolling is accomplished by a foot activated brake lever 25. The function of the brake levers 25 and the brake mechanism associated therewith is preferably one well known to the art skilled person and used in other wheeled implements such as strollers. The brake levers 25 can also be connected by an appropriate mechanism (not shown) to a brake handle associated with the handle 13 of the chair to allow use of the brakes 24 for slowing down the chair. The fixed rear wheels are protected by a wheel housing 20 which also supports the brake levers 25 and encloses the associated brake mechanism (not shown). The wheel housing 20 is provided with a rearward extension 21 at the bottom rear end thereof. Extension 21 is in the shape of a flat, rectangular block and aids an operator pushing the chair in tilting the chair upward at its front end to, for example, move up a curb or step. The combination of extension 21 and housing 20 provides a lever having as its fulcrum the axis of rotation of the associated wheel 22. The operator can place one foot on one of the extensions 21 and pull the handle 13 backwards which will lift the front end of the base portion 11 and the associated wheels 22 off the ground. Subsequent forward pushing with the same foot on the extension 21 will force the wheelchair forward to place the front wheels on the top of the curb or step. The extension 21 , and possibly the wheel housing 20, are preferably reinforced to withstand the downward and forward pressure exerted thereon by the operator during this operation. The base portion 11 of the frame 10 is forwardly tapered in width, which means the front crossbar 10c is shorter than top crossbar 10d and center crossbar 10e. No crossbar is provided at the rear end of the base portion 11. Thus, the base portion 11 defines a rearwardly open, substantially U-shaped, tapered opening for receiving the base portion of another, identical wheelchair and, thus, nesting therewith. The base cover 19 is mounted over and covers the base portion 11 of the frame 10 and has a cutout 26 at the rear (Fig. 5) to allow passage of the front end of the base portion of another wheelchair for nesting. Morever, the base cover 19 is tapered along its top and side surfaces to allow nesting with other, identical wheelchairs. The base cover 19 not only provides the wheelchair with an aesthetically pleasing appearance but also prevents the person using the chair getting caught with a leg or foot in the tubing of the base portion 11 or between that tubing and the floor. The backrest panel 16 provides a backrest for a person using the wheelchair, is attached to the supporting portion of the frame and laterally covers the tubing of the supporting portion 12 above the base cover 9. A rearwardly open, substantially rectangular cutout 30 is provided in each side of the backrest panel 16 to accommodate armrest support brackets 32 (see Figs. 7 and 8). The armrests 15 are mounted on and swivel around the armrest support brackets 32 between an arm supporting position as shown in Figs. 1 and 2, and a folded or storage condition as shown in Fig. 4. Each armrest can be moved independently of the other. The armrests 15 each include a transverse cylindrical bore 31 at a rear end (Fig. 8) which is sized to receive one of the armrest support brackets 32 which are made of square steel tubing. An armrest base washer 33 is mounted over each support bracket 32 to prevent the armrest 15 rubbing against the backrest panel 16 and possibly jamming. A square opening 34 at the center of the washer 33 is sized to fit over the support bracket 32 to prevent the washer from rotating relative to the support bracket. Armrest mounting clips 39 are provided to hold the armrests 15 in place on the respective support bracket 32. The mounting clip has a circular base plate 35 with a central, square recess 36 to non-rotatably fit over the support bracket 32. It further includes a pair of spaced apart parallel mounting legs 38 with hook- shaped ends 37 which legs are positioned to fit inside the mounting bracket and interlock therewith, by way of the hook-shaped ends, for removably mounting the armrest 15 to the support bracket 32. Removal of the armrest 15 is achieved by forcing the free ends of the mounting legs 36 together until the hook-shaped ends 37 disengage from the mounting bracket 32. The base washer 33 includes a pair of bosses 40 which cooperate with arcuate recesses 41 located in each armrest 15 around the transverse bore 31 to limit the rotation of the armrest and provide a stop for each of the arm supporting position and the storage position. The seat 14 is pivotally mounted to the support portion 12 for rotation around the pivot axis defined by center crossbar 10e between a patient supporting position (Figs. 1 , 2 and 8) and a storage position (Fig. 4) wherein the seat 14 is oriented substantially parallel to the support portion 12. The seat is pivotally connected to the support portion 12 by the center crossbar 10e and is supported at a front edge 50 by a seat support panel 52 in the patient supporting position. At least some of the weight of a person placed on the seat is supported on the base cover 19 by the seat support panel 52, which is pivotally attached at its top end to the forward underside of the seat by way of a seat support bar 53. The support panel 52 has an intermediate step 55 for engagement with a front top edge 51 of the base cover 19 to support thereon at least part of the load on the seat 54. The support panel 52 is provided with a pair of downwardly protruding pins 56 (see Fig. 2) for engagement of complementary recesses 54 (Fig. 4) in the base cover 19 to releasably interlock the support panel 52 and the base cover 19. In the folded condition of the wheelchair, the seat support panel 52 is adjacent parallel to the underside of the seat 14 (Fig. 4). The bottom portion of the seat support panel 52 in the patient supporting position of the seat 14 extends below the base cover 19 and to a point above the floor. A pair of footrests 60 are pivotally attached to a bottom end of the seat support panel 52 by way of a footrest support tube 62. Each footrest includes on the surface thereof a number of anti-skid ribs 64. The footrests are individually rotatable about the support tube 62 between a foot supporting position wherein the footrest extends substantially horizontally forwardly from the seat support panel 52 (Fig. 1) and a folded position wherein the footrest is adjacent parallel to the support panel 52 (Figs. 2 and 4). A leg support bracket 70 (Figs. 1 , 2, 6) for the supporting one leg of a person seated in the wheelchair is pivotally attached to the seat 14 by way of a pivot bar 72 mounted below the seat and at a front edge thereof. The leg support is attached for movement between a leg supporting position wherein the bracket extends substantially horizontally forwardly from the seat (Figs. 1 , 2) and a storage position wherein the leg support bracket is adjacent parallel the seat support panel 52 (Fig. 6). The leg support bracket 70 is slidably mounted to the pivot bar 72 so that the bracket 70 can be laterally moved from one side of the seat to the other for supporting of either leg of the wheelchair user. In the leg supporting position, the leg supporting bracket 52 is supported by a foldable support brace 74 which is at one end pivotally attached to the underside of the leg support bracket and at the other end engages one of multiple horizontal slots 76 in the seat support panel 52. Movement of the support brace 74 between different slots 76 allows for adjustment of the angle of the leg support bracket 70. The support brace 74 is foldable against the underside of the leg support bracket 70 to fit thereinto. In the preferred embodiment, the leg support bracket 70 is extendable and for this purpose includes a leg extension 78 which is slidably connected with the leg support bracket 70 for movement between an extended position wherein part of the leg extension protrudes beyond a front edge of the leg support bracket 70 (Fig. 2) and an unextended position, wherein the leg extension 78 substantially covers the support bracket 70 (Fig. 1). Mounted to the rear of the wheelchair frame 10, is a moulded equipment carrier 38 which accommodates various medical accessories (Fig. 5). At one side of the carrier 18 is a circular shaped recess 39 to hold a medical oxygen tank. Near the top end of the carrier is provided an integral clamp 40 with a strap to restrain the medical oxygen tank. At the other side of the carrier 18 is provided a pouch 41 for holding medical records. The upper end of the carrier 18 accommodates an elongated tubular IV pole 42 of conventional construction for supporting such items as an intravenous bottle or bag and a dispensing or metering pump (not shown). Figures 2 and 4 illustrate the carrier/wheelchair in the folded condition whereby the seat 14 and armrests 15 are folded upwards for compact storage. A second, identical wheelchair is shown in the nested condition in Figure 2. As is apparent, the four wheels 11 support the wheelchair in the folded position. Moreover, the carrier 18 remains in position relative to the rigid frame 10 and continues to provide equipment supporting functions even in the folded mode of the wheelchair. Figure 6 illustrates the carrier/wheelchair in the condition where the armrests 15 and seat 14 are folded upwards and the base portion 11 is slid under a patient's bed 68 which allows for minimum usage of space for storage of the wheelchair and full medical equipment supporting function bedside. Thus, the equipment need not be removed from the wheelchair to move the patient between the wheelchair and the bed and can remain in the carrier 18 even while the patient is in the bed. Thus, not only is the amount of storage space required for the wheelchair significantly reduced, but the requirement for a separate bedside carrier is obviated. The amount of staff time involved in transfer of the patient is thus reduced. To further reduce the incidence of unauthorized removal of wheelchairs from hospital premises, the wheelchair may be colour coded for identification and the name of the institution can be moulded into the frame. A permanent or detachable motor/power pack can be fitted under the base cover 19 for driving the rear wheels of the wheelchair in a manner well known to the person skilled in the art. This can be achieved even without interfering with the nesting function of the base portion 11 and the base cover 19. The wheelchair can be pre¬ wired in the armrests 19 and frame 10 for manual or programmed control of the motor/power pack. A sensor can be placed at the leading edge of the frame 10 and electrically connected to the control to enable the chair to be programmed to follow a predetermined, designated guide ribbon path embedded in the hospital floor and automatically transport a patient to a specific destination on the premises. The motor/power pack can also be manually operated in a manner known in the art by way of a joystick controller detachable or permanently installed on either armrest 15. In the alternative, the joystick controller may be mounted at the handle 13 of the chair to be controlled by a person other than the occupant of the wheelchair. Changes and modifications in the specifically described embodiments can be carried out without departing from the scope of the invention which is intended to be limited only by the scope of the appended claims.

Claims: THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY AND PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS: 1. A wheelchair, comprising: a rigid frame which consists of a base portion and a support portion extending upward from the base portion in a substantially vertical orientation; the base being shaped and constructed for nesting with the base of another, identical wheelchair; means for movably supporting the base portion on a supporting surface; a seat for supporting the weight of a person, the seat being pivotally mounted on the wheelchair for movement between a patient supporting position wherein the person can sit on the seat, and a storage position wherein the seat is positioned substantially parallel to the support portion. 2. A wheelchair as defined in claim 1 , wherein the base portion is shaped and constructed for positioning at least part of the base portion under a patient's bed with the seat in storage position. 3. A wheelchair as defined in claim 1 , further comprising at least one armrest pivotally mounted to the support portion for movement between an operating position wherein the arm rest is positioned to support an arm of the person and a storage position wherein the arm rest extends substantially parallel to the support portion. 4. A wheelchair as defined in claim 3, further comprising a backrest panel removably attached to the support portion and a pair of spaced apart parallel armrests respectively pivotally mounted to the support portion at respective sides of the backrest panel. 5. A wheelchair as defined in claim 4, wherein the armrests are pivotable independently of each other and the seat. 6. A wheelchair as defined in claim 1 , further comprising a seat support panel for supporting a front edge of the seat on the base portion of the frame when the seat is in the patient supporting position. 7. A wheelchair as defined in claims 1 to 6, further comprising a base cover for covering the base portion, whereby the seat support panel supports the seat on the base cover. 8. A wheelchair as defined in claims 1 to 7, further comprising at least one footrest pivotally mounted to a bottom end of the seat support panel for movement between an operating position wherein the footrest can support a patient's foot off the ground and a storage position wherein the footrest is adjacent parallel to the seat support panel. 9. A wheelchair as defined in claims 1 to 8, comprising a pair of spaced apart parallel footrests mounted to the seat supporting panel for independent pivotal movement between foot supporting and storage positions. 10. A wheelchair as defined in claims 1 to 9, further comprising a leg support bracket pivotally attached to one of the seat and the seat support panel for movement between a leg supporting position wherein the bracket extends substantially horizontally forwardly from the seat and a storage position wherein the leg support bracket is adjacent parallel the seat support panel. 11. A wheelchair as defined in claims 1 to 10, wherein the base portion is forwardly tapered in width and has the shape of a rearwardly open U for allowing insertion of the base portion of another substantially identical wheelchair during nesting.

Inventors: SUNDERLAND MARK, SUNDERLAND, MARK
Applicants: MOBILAID CORP, SUNDERLAND MARK, MOBILAID CORPORATION, SUNDERLAND, MARK
Application year: 1998
Main classification: A61G5
IPC codes: A61G5, B62B3