Abstract:
A collapsible wheelchair assembly includes left and right frame sections that are separably fastened using a slide tube assembly. The slide tube assembly is fastened to the frame section with locking pins that can be manually removed without tools. The design allows the right and left frame sections to be completely separated for transport and storage.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is entitled to the benefit of provisional application No. 60/515,591 filed on Oct. 30, 2003. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to a uniquely designed wheelchair that can be quickly and easily separated into two sections for transport and storage. 
   DESCRIPTION OF THE PRIOR ART 
   The elderly, the infirm and others who have various physical disabilities often require a wheelchair for ambulation. Accordingly, it is often necessary to transport a wheelchair in a vehicle along with the patient. However, because wheelchairs are inherently bulky, storing them within a vehicle is difficult, if not impossible. Though some wheelchairs are partially collapsible, they still occupy a significant amount of storage space. A myriad of folding and collapsible wheelchairs exist in the prior art which are purportedly designed to facilitate transport and storage. For example, U.S. Pat. No. 4,415,177 issued to Hale et al. discloses a wheelchair including a folding backrest, a removable headrest, a set of rotatable foot pads, a set of rotatable arms and foldable handles. 
   U.S. Pat. No. 4,542,918 issued to Singleton discloses a foldable wheelchair including two side frames connected by a foldable linkage. 
   U.S. Pat. No. 4,887,826 issued to Kantner discloses a lightweight foldable wheelchair including a seat having a base and a back hingedly attached thereto whereby the back is foldable to overlie the base. A pair of large wheels are removably mounted to each of two ends of an axle. 
   U.S. Pat. No. 5,568,933 issued to Mizuno discloses a foldable wheelchair including a pair of parallel main frames connected to each other on a rear side via a detachable back support and on a front side via vertical foot plates. Large wheels and a seat plate are detachably coupled to the main frame. The large wheels can be removed from the wheelchair to pass through most doorways. 
   U.S. Pat. No. 6,343,805 issued to Roy discloses a folding wheelchair including a plurality of interconnecting folding sections allowing the wheelchair to be collapsed for transport and storage. 
   Though a variety of collapsible wheelchairs exist in the prior art, most include folding components that only minimally reduce the size of the wheelchair. The present invention provides a uniquely designed wheelchair that may be quickly separated into two sections without the need for tools, allowing it to be easily transported or stored. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a collapsible wheelchair. The device comprises a left frame section and a right frame section. Each frame section has a lower rail with a front and a rear riser extending therefrom. The rear riser on each frame section extends to a height significantly greater than that of the front riser and includes a handle outwardly extending therefrom. Each frame section is mounted on a pair of wheels. A pair of crossbars are attached to the lower rails for supporting a seat member. Each crossbar includes an aperture on an intermediate portion thereof that removably receives a nut and bolt to join the two crossbars when the wheelchair is an expanded, operable configuration. Each crossbar includes a lower end having a sleeve thereon that receives one of the lower rails allowing the crossbar to pivot relative thereto. At an upper end of each crossbar is a seat support tube. A seat member includes two opposing edges, one of which is permanently attached to one of the seat support tubes. The other seat support tube includes a plurality of twist eyelets thereon that are removably received within mating apertures on the opposing edge of the seat member allowing the seat member to be detached. Each front riser includes an opening at a top end thereof that telescopically receives a slide tube having a horizontal sleeve at the upper end thereof. The sleeve removably receives the front end of the seat support tube. A plug is removably received within the opposing side of the sleeve and includes a bore for receiving a locking pin to lock the plug and seat support tube within the sleeve. The rear end of each seat support tube includes an opening that slidably receives an elongated arm having a C-shaped clamp member at an end thereof. The C-shaped clamp member encompasses the rear riser on the corresponding frame section further securing the seat support tube thereto. 
   It is therefore an object of the present invention to provide a wheelchair that can be easily separated into two sections for transport or storage. 
   It is therefore another object of the present invention to provide a wheelchair that can be collapsed or disassembled without the need for tools or assistance. 
   Other objects, features, and advantages of the present invention will become readily apparent from the following detailed description of the preferred embodiment when considered with the attached drawings and the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the wheelchair in a partially collapsed configuration. 
       FIG. 2  is a front view of the wheelchair in an operable configuration. 
       FIG. 3  is a rear view of the wheelchair in an operable configuration. 
       FIG. 4  is a side view of a crossbar according to the present invention. 
       FIG. 5  is a top view of a crossbar according to the present invention. 
       FIG. 6  is a detailed view of the slide tube assembly. 
       FIG. 7  is a top view of the slide tube assembly. 
       FIG. 8  is a detailed view of the tube and locking pin assembly. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The present invention relates to a separable wheelchair. The device comprises a left frame section  1  and a right frame section  2 , each of which is mounted on a pair of wheels  6 . A pair of handbrakes  33  selectively lock the wheels to prevent the wheelchair from rolling. Each frame section has a lower rail  3  with a front  4  and a rear  5  riser extending therefrom. The rear riser on each frame section extends to a height significantly greater than that of the front riser and includes a handle  7  outwardly extending therefrom. A backrest member  15  includes two opposing edges, one 16 of which is permanently fastened to a rear riser. The other edge  17  includes a plurality of apertures  18  for receiving mating twist eyelets  19  longitudinally disposed on the other rear riser. 
   A pair of intersecting crossbars  8  are attached to the lower rails for supporting a seat member  9 . Each crossbar includes an aperture  10  on an intermediate portion thereof that removably receives a fastener such as a nut  11  and bolt  12  to fixedly join the two crossbars when the wheelchair is an expanded, operable position. Each crossbar includes a lower end having a sleeve  13  thereon that receives one of the lower rails allowing it to pivot relative thereto. At an upper end of each crossbar is a seat support tube  14 . 
   The seat member  9  includes two opposing edges, one  21  of which is permanently attached to one of the seat support tubes. The other seat support tube includes a plurality of twist eyelets  22  thereon that are received within mating apertures  23  on the opposing edge of the seat member allowing the seat member to be detached. 
   Each seat support tube includes a front end that is removably secured to the front riser on each frame section with a slide tube assembly  43 . The slide tube assembly includes a slide tube  25  having a horizontal sleeve  26  at the upper end thereof. Each slide tube is telescopically received within an opening  24  at a top end of each front riser. The sleeve removably receives the front end of the seat support tube at one end and a plug  27  within the opposing end. The plugs, sleeves and seat support tubes each include a bore for receiving a locking pin  28  to secure the plug and seat support tube within the sleeve. The rear end of each seat support tube includes an opening  29  that slidably receives an elongated arm  30  having a C-shaped clamp member  31  at a distal end thereof. The C-shaped clamp member encompasses the rear riser on the corresponding frame section. 
   Adjacent each frame member is a padded armrest  48  and armrest frame assembly  49  having a large diameter wheel  52  thereon. A pivotal footrest  50  is mounted on each frame member for enhanced comfort to the user. 
   The method of disassembling the above-described wheelchair for transport or storage is as follows. Each handbrake is applied to anchor the wheelchair. The seat and backrest members are partially collapsed by raising the seat member slightly. The twist eyelets on the rear riser and the corresponding seat support tube are unlocked and the seat and backrest members are detached. The left frame section is placed against a supporting surface and the crossbar fasteners are loosened, but not removed. The locking pin and plug are temporarily removed to release the seat support tube and then reinstalled. The elongated arms are detached from the rear risers and the crossbar fasteners are removed allowing the crossbars, and thus each frame section, to be separated. Each crossbar can then be folded against its respective frame section allowing each frame section to be separately and compactly stored. 
   The above described device is not limited to the exact details of construction and enumeration of parts provided herein. Furthermore, the size, shape and materials of construction of the various components can be varied. 
   Although there has been shown and described the preferred embodiment of the present invention, it will be readily apparent to those skilled in the art that modifications may be made thereto which do not exceed the scope of the appended claims. Therefore, the scope of the invention is only to be limited by the following claims.