A stair-climbing wheelchair carrier

Abstract: A stair-climbing wheelcarrier comprises a carrier portion comprising a pair of endless belt crawlers and a handle rotatably mounted on the carrier portion. A guide body is provided to mount a wheelchair and secured to the handle so as to be pivoted together with the handle. An electric screw jack is provided between the carrier portion and the guide body for holding the guide body at a desired position.

Description: The present invention relates to a stair-climbing wheelchair carrier on which a wheelchair with a passenger seated therein is mounted for the transportation of the passenger up and down stairs as well as on the ground. Japanese Utility Model Publication No. 2-3985 discloses a stair-climbing wheelchair carrrier comprising a wheelchair carrier portion having a pair of crawlers, each of which is provided between a driving wheel and an idling wheel with a span extending over at least two steps of the staircase and a motor for driving the crawlers, a handle mounted on the wheelchair carrier for holding a wheelchair, and a pair of wheels, each of which can be lowered from the crawler for carrying the wheelchair on the ground. However, in the conventional wheelchair carrier, it is troublesome to change the stair-climbing wheelchair carrier from the condition for climbing stairs to the condition for movement on the ground, and the construction for the change is complicated. The angular position of the wheelchair with respect to the carrier cannot be adjusted. Consequently, when ascending or descending stairs, the wheelchair may be inclined and, hence, the disabled person seated on the chair is not held in a comfortable position and the disabled person in the wheelchair feels uneasy. Further prior art of relevance is disclosed in French patent application No. FR-A-2 599 700 and British Patent No. GB-A-1 428 315. The invention defined in claim 1 of this application is characterised by reference to the closest prior art of FR-A-2 599 700. An object of the present invention is to provide a stair climbing wheelchair carrier in which the angle of the wheelchair with respect to the carrier can be adjusted, thereby eliminating the above described disadvantage. Accordingly the present invention provides a wheelchair carrier capable of climbing stairs and having: a carrier portion and a guide body, the carrier portion comprising a frame, a pair of endless belt crawlers each having a span extending over at least two steps of the stairs and an oblique overhang lifting an end of each belt crawler to a height exceeding that of the stairs, a drive motor for the belt crawlers, the guide body having a pair of spaced wheel holding plates to receive the wheels of a wheelchair and having a handle mounted thereon, the guide body being pivotally mounted on the frame, and characterised in that a jack is provided to act between the frame and the guide body to pivot the guide body with respect to the frame, and housings disposed one each beneath each wheel holding plate to receive a ramp plate so that the ramp plates can be partially withdrawn to provide a ramp. The guide body may have a caster on the underside thereof at a front portion and a pair of wheels at a rear portion so as to enable the carrier to move on the ground. A wheelchair carrier constructed in accordance with the present invention will now be described, by way of example only, with reference to the accompanying illustrative drawings, in which: Figure 1 is a partially sectioned side elevation with a wheel chair, shown in ghost lines ,located to be carried, Figure 2 is a partially sectioned plan view, Figure 3 is a side elevation illustrating the pivoting action of the guide body with respect to the carrier portion and the extension of the ramp plates, Figure 4 is a sectional detail of the guide body on the line IV-IV in Figure 3, Figure 5 is a side elevation of the carrier carrying a wheelchair up a stair. Referring to Figs. 1 and 2, a stair-climbing wheelchair carrier 1 of the present invention comprises a wheelchair carrier portion 2, a handle 3, and a guide body 4 integrally connected to the handle 3. The wheelchair carrier portion 2 has a pair of rail-frames 5 of aluminum die-casting, rear ends of which are curved upwards like a sleigh. These frames 5 are disposed parallel on each side of the carrier portion 2. Flanges 6 formed on ends of the frames 5 are connected to each other through a reduction gear case 9 which combines a driving motor 7 and a reduction gear 8. A plurality of connecting members 10 are bridged over the frames 5 at intermediate positions of the longitudinal of the frame 5 to constitute the frame body of the wheelchair carrier. A battery 11 as a powder source of the driving motor 7 is supported on the connecting members 10. A pair of driving wheels 13 are secured to a driving shaft 12 connected to the reduction gear 8 and a pair of idlers 14 are mounted on a shaft 14a laterally provided on the rear and upper end of overhang portions of the frames 5. A belt crawler 15 is engaged with guide grooves of the driving wheel 13, a grounding guide portion 16 provided on the frame 5, a lower guide groove of an overhang 17, and guide grooves of the idling wheel 14. A pair of belt crawlers 15 are parallel with each other, and the distance between the belt crawler 15 is smaller than the distance between a pair of wheels of a wheelchair 21. Considering the road and staircase conditions, the belt crawlers 15 are made of elastic synthetic rubber to absorb shock as well as to protect the floor plate or staircase. The belt crawler 15 is provided with lugs 15a disposed at a predetermined interval to properly engage with steps of the stair. The inner surface of the belt crawler 15 is provided with lugs 15b engageable with driving teeth, preventing the belt crawler from slipping around the driving wheels 13. The belt crawler 15 has a span extending over at least two steps of the staircase. The guide body 4 comprises a cover plate 25 provided for converting the wheelchair carrier portion 2 excepting the battery 11, a pair of wheel holding plates 24 secured to the opposite sides of the cover plate 25 for holding wheels 22 and casters 23 of the wheelchair 21. The holding plates 24 has a base plate and a pair of upright side plates to have a U-shaped section. Further, the plates 24 is formed to have a width enough to guide and support the wheels 22 and casters 23 of the wheelchair 21 along the guide body 4 when the wheelchair 21 is mounted on the wheelchair carrier 1. Each holding plate 24 is provided with a hollow housing portion 29 formed on the underside thereof for housing a ramp plate 30 which is used for loading or unloading the wheelchair 21 on the holding plate 24. When the ramp plate 30 is housed in the housing portion 29, the plate 30 is engaged with the housing portion 29 so as to prevent the ramp plate from falling out of the housing portion. The ramp plate 30 is pulled out from the housing portion 29 when using. At that time, the innermost end of the ramp plate 30 is engaged with a stopper of the housing portion 29. A pair of bearing portion 19 are formed on the frames 5 near the overhang 17. A shaft 18 is securely mounted in the bearing portion 19. As shown in Fig. 4, both ends of the shaft 18 are mounted on supporting plates 18a which are secured to the outer side plates of the wheel holding plates 24. A base end of each wheel holding plate 24 is pivotally mounted on the shaft 18. The shaft 18 also serves as a stopper for stopping the wheels 22 when the wheelchair 21 is mounted on the holding plates 24. The shaft 18 has a pair of idlers 20 rotatably mounted on opposite ends thereof. Each idlers 20 engages with the belt crawler 15, so that the upper moving portion of the belt crawler 15 is deflected to a substantially horizontal plane. The handle 3 is integrally mounted on the holding plate 24 at a rear portion thereof. The handle 3 has a connecting plate 3a secured to an inner side plate of the wheel holding plate 24 and rotatably mounted on the shaft 18. Thus, the handle 3 and the guide body 4 are pivotally mounted on the shaft 18. A single caster 26 is provided on the underside of the connecting member 24a. A pair of wheels 27 are provided on the underside of the holding plates 24 at rear ends thereof. Both the caster 26 and the wheels 27 are provided to be projected lower than the belt crawlers 15. An electric screw jack 28 is provided on the underside of the cover plate 25 of the guide body 4 for pivoting the guide body 4 together with the handle 3 about the shaft 18. As shown in Figs. 1 and 3, the electric screw jack 28 comprises a motor 28a, a reduction gear 28b, and a screw rod 28c projected by the motor without rotating. The end of the rod is connected to the cover plate 25, and the base end of the motor 28a is connected to one of the connecting members 10. When the rod 28c is contracted in the jack 28, the caster 26 and the wheels 27 are grounded. When the rod 28a is extended from the jack, the guide body 4 is pivoted about the shaft 18 so that the caster 26 and the wheels 27 are raised from the ground. Thus, the crawlers 15 are grounded. The wheelchair 21 is connected to the wheelchair carrier 1 by a seat belt 31 attached to the handle 3 through a buckle 32. An electric circuit connected to the battery 11, the driving motor 7 and the motor 28a is mounted in the buckle 32 for operating the motors 7 and 28a. When the buckle 32 is disengaged, the circuit is adapted to be disconnected, so that the motors 7 and 28a can not be operated. Further, a limit switch in the electric circuit is provided on the screw jack 28. The motor 7 is not operated unless the screw jack 28 is operated to extend the rod 28c. A switch device 34 is provided near grips 33 of the handle 3 for operating the driving motor 7 and the screw jack 28. To mount the wheelchair 21 on the carrier 1, the ramp plate 30 is pulled out from housing portion 29. Thereafter, the wheelchair 21 is moved on the guide plates 25 passing through ramp plate 30 until the rear wheels 22 about on the shaft 18. In order to carry the wheelchair 21 by the wheelchair carrier 1 on the ground or the landing of the stairs, the carrier 1 can be moved by wheels 27 and the caster 26 by pushing through the handle 3. When ascending or descending the stairs, the piston rod 28a is extended by operating the switch device 34. Thus, the handle 3 and the guide body 4 are pivoted about the shaft 18 to the inclined position so that the wheelchair 21 is held in position for ascending or descending the stairs. The angle of the wheelchair can be adjusted by properly operating the switch device 34. Referring to Fig. 5, the belt crawlers 15 contact with the corners of the steps S of the stairs and are driven by the motor 7. Thus, the carrier 1 can go up or down the stairs by the crawlers 15. In the present invention, unless the wheelchair 21 is secured to the handle 3 by coupling the buckle 32 of the seat belt 31, the circuit to operate the motor 7 and the jack 28 is not closed. Further, if the rod 28a of the jack 28 is not extended, the motor 7 is not operated. Thus, the safety of the carrier is ensured. The ground running position of the guide body 4 of the carrier 1 is easily changed to the stair-climbing position by operating the switch device 34. To unload the wheelchair 21 from the carrier 1, the jack 28 is operated to retract the rod 28a to lower the guide body 4, so that the caster 26 and the wheels 27 are grounded. The ramp plates 30 are pulled out from the housings 29 and the wheelchair 21 is released from the handle 31 by disengaging the buckle 32. The wheelchair 21 is removed in the reverse order to the above described manner for mounting the wheelchair. In accordance with the present invention, the star-climbing wheelchair carrier is provided with the jack for positioning the carrier to the stair-climbing position. Since the jack holds the wheelchair at any position, the angle of the wheelchair can be adjusted to the horizontal position on the stairs. When the wheelchair is moved on the ground, the carrier is pushed through the handle so that the wheelchair on the carrier can be safely moved on the ground with the caster and the wheels. When ascending or descending the stair, the rod of the jack is extended to raise the guide body so that the caster and the wheels are removed from the ground. Thus, the crawlers can be safely moved up or down the stairs with keeping the wheelchair horizontal. The ramp plates are housed in the housing portions so that the appearance of the carrier is not aggravated. Unless the buckle of the seat belt is coupled, the power is not applied to the motors. Consequently, the dangerous stair-climbing operation without connecting the wheelchair with the carrier is prevented. While the presently preferred embodiment of the present invention has been shown and described, it is to be understood that this disclosure is for the purpose illustration and that various changes and modifications may be made without departing from the scope of the invention as set forth in the appended claims.

Claims: A wheelchair carrier capable of climbing stairs and having: a carrier portion (2) and a guide body (4), the carrier portion (2) comprising a frame (5), a pair of endless belt crawlers (15) each having a span extending over at least two steps of the stairs and an oblique overhang (17) lifting an end of each belt crawler (15) to a height exceeding that of the stairs, a drive motor (7) for the belt crawlers (15), the guide body (4) having a pair of spaced wheel holding plates (24) to receive the wheels of a wheelchair and having a handle (3) mounted thereon, the guide body (4) being pivotally mounted on the frame (5), and characterised in that a jack (28) is provided to act between the frame (5) and the guide body (4) to pivot the guide body with respect to the frame (5), and housings (29) disposed one each beneath each wheel holding plate (24) to receive a ramp plate (30) so that the ramp plates (30) can be partially withdrawn to provide a ramp. A wheelchair carrier as claimed in claim 1 wherein the guide body (4) has a caster (26) at a front portion and a pair of wheels (27) at a rear portion to support the carrier on the ground. A wheelchair carrier as claimed in claim 1 or claim 2 wherein the jack (28) is an electric screw jack. A wheelchair carrier as claimed in any preceding claim wherein the handle includes a belt (31) for securing the wheelchair to the handle (3), said belt (31) including an openable and closable buckle (32) which includes electrical circuit means which only permits the drive motor (7) and the screw jack (28) to be operated when the buckle (32) is closed.

Inventors: MISAWA RINTARO, MISAWA, RINTARO
Applicants: SUNWA SHARYO MFG CO, SUNWA SHARYO MANUFACTURING CO., LTD.
Application year: 1991
Main classification: A61G5
IPC codes: B62D55, A61G3, A61G5