EASY TO USE PORTABLE MANUAL STANDING WHEELCHAIR WITH SAFETY FEATURES AND FOR OUTDOOR USE

Abstract

The invention is for a standing 3 wheeled wheelchair with a pivoted seat having link means, a dyad means, removable side handle actuator means, a lockable knee support with interlocking cam means, which enables the user to stand effortlessly and safely in the wheel chair.

Claims

1. A standing wheelchair comprising: a. a chassis having a first end and a rear end, b. a front wheel connected to the front end of the chassis and a pair of rear wheels supporting the wheelchair, c. a pivotable seat means of a first link (ab), the said seat pivotable between a generally horizontal seated position and an angled standing position, and having a seating surface and a backrest means of a second link (cd), such that (ab), (bc), (cd) and (da) form a four bar parallelogram link means, d. a driver dyad means comprising of four links (be), (ef), (fg) and (bg) which is adapted to actuate the said 4-bar mechanism, e. a pair of removably attached side handle actuator means, each handle actuator means connected rigidly to link (ef) of the driver dyad means and cooperatively associated with the 4-bar link means for actuating the seat means between the seated position and standing position, f. a lockable knee support means attached to the front end of the said seat means moveable between a lock state and open operational state, and g. a pair of side interlocking cam means, each interlocking cam means coupled to the knee support means and the corresponding side handle actuator means for causing the said handle actuator means to move only when the knee support means is in lock state.

2. The standing wheelchair as claimed in claim 1 is such that when length of link (ad) is equal to length of link (bc), a parallelogram is formed.

3. The standing wheelchair as claimed in claim 1 is such that wherein each of the said interlocking cam means includes a locking pin, a plunger and a cable means such that the locking pin is selectively extending into and away from the handle actuator means, correspondingly to free state and lock state of the knee support means, thereby corresponding to lock state and free operation state of the handle actuator means.

4. The standing wheelchair as claimed in claim 1, wherein at least one interlocking cam means is arranged on each side of the wheelchair cooperatively operating with the corresponding side handle actuator means.

5. The standing wheelchair as claimed in claim 1 includes another interlocking means comprising of a moveable armrest and a plate attached to the armrest means which is in turn attached to the backrest means, the said plate arranged in the motion pathway of the handle actuator means, such that the armrest along with the fixed plate extends into and away from the handle actuator means motion pathway on the basis of rotational motion of the handle means, thereby correspondingly creating a lock state and free operate state of the handle actuator means.

6. The standing wheelchair as claimed in claim 1 is such that wherein each of the said actuating handle means includes a locking pin, a plunger and a cable means such that the locking pin is selectively extending into and away from the chassis means by the actuation of the first handle position (h1), correspondingly to lock state and free state of the standing actuating handle means.

Description

DETAILED DESCRIPTION OF DRAWINGS

[0020] FIG. 1 Top View of the standing wheelchair in the sitting positionShows the wide position of the footrest

[0021] FIG. 1(a) Mechanism pivots on the wheelchair (wheel is hidden)

[0022] FIG. 2 Side view of the wheelchair in standing positionhandle design to not obstruct with the leg of the user

[0023] FIG. 2(a) Layout description of the wheelchair

[0024] FIG. 3 Demonstrates the handle in removed position

[0025] FIG. 3(a) Mechanism movement as it is actuated into standing position

[0026] FIG. 4 Figures show the actuation of the knee block cam

[0027] FIG. 4(a) Wheelchair in standing position

[0028] FIG. 5 Demos the actuation of the pin to enable the standing mechanism

[0029] FIG. 5(a) Top view of the wheelchair showing(a) Longer wheelbase (b) Footrest position wide and angled out

[0030] FIG. 6 Actuation of the handle knob powers the pin disengaging the standing lock and enabling the user to get into standing position

[0031] FIG. 6 (a) demonstrates handle in the standing position without interfering with the leg of the user

[0032] FIG. 7 Demonstrates the stopper on the armrest for the handle

[0033] FIG. 7 (a) Detachment of the handle to improve portability

[0034] FIG. 8 Mechanism to lock the standing mechanism with the knee support(a)

[0035] Knee block CAM (b) Plunger

[0036] FIG. 8(a) Figures show the actuation of the knee block cam by placing the knee support

[0037] FIG. 8(b) Demonstrates the actuation of the pin to enable the standing mechanism

[0038] FIG. 9 Standing lock at the handle h1resting position of pin (d) and handle h1 on left side and actuated position of pin and handle h1 on right side. The obstructing plate is marked as (e).

[0039] FIG. 10 Demonstrates the stopper on the armrest for the handle

[0040] Now the invention is described with respect to drawings for better understanding of the invention

[0041] The unique feature of the design of the standing mechanism is the design of the handle which provides a large leverage without obstructing with the leg of the user and being removable.

[0042] The standing mechanism is designed using a 6-bar (4-bar and driver dyad) linkage mechanism. The pivots of the mechanism in the wheelchair are shown in FIG. 1 (A). Layout of the mechanism is shown in FIG. 2 (A). Link ab,bc,cd,da form the 4-bar mechanism. Link ab is used as the seat of the wheelchair. Backrest is rigidly connected to the link cd. In a particular configuration when length of ad is same as that of bc, this forms a parallelogram mechanism and it ensures that backrest is along the same orientation as the users moves into standing position. Links be, ef, fg and bg form the driver dyad system which actuates the 4 bar mechanism. The mechanism is actuated by the standing handle which is rigidly connected to link ef. Different positions during actuation into standing position shown in FIG. 3(A). As the standing handle is actuated the wheelchair gets into standing position as shown in FIG. 4 (A).

[0043] The design uses a 3 wheel base to make the wheelchair more adaptable to outdoor scenario as shown in FIG. 5 (A). As the wheelchair base is longer, no extra mechanism is required to ensure stability in standing position. Many existing standing wheelchair require an extra mechanism which lowers the footrest as the user comes into standing to ensure the stability of the wheelchair. To avoid obstruction between the footrest and the castor wheels, footrest is moved sideways and angled out as shown in FIG. 5 (A). In this position of the footrest, it is often observed that some part of the user's leg, (especially near the knee) is out of the width of the seat and could interfere with the standing mechanism handle. Especially as the users might not have any sensation in the leg, this could be potentially dangerous to the user. The unique feature of this design is the configuration of the mechanism including the standing handle with a greater leverage without obstructing with the leg of the user. This is accomplished by ensuring the handle position near h2 ends before the cushion on the seat as shown in FIG. 6 (A). Larger handle provides a greater leverage reducing the effort required to get into standing position. Larger handle occupies a greater space and causes a restriction in the portability of the wheelchair. The handle has been designed to be removable to improve the portability of the wheelchair. Handle can be removed as shown in the FIG. 7 (A).

[0044] Safety of the Standing Mechanism

[0045] The users have little or no strength in their legs to stand independently. Hence, a support is essential to enable the user to stand, which is provided below the knee. Standing without the use of this support is potentially dangerous to the user. Hence, a unique extra safety lock mechanism has been incorporated which disables the standing mechanism without the knee support. A cam type arrangement is designed in the knee support receiver on the frame which is activated on placing the knee support. When the knee support is not placed, as shown in right side of FIG. 8. (A), the cam remains in the rested position. When the knee support is placed as shown in the left side of FIG. 8(B), the insertion of the knee support pipe presses against the cam and causes it to rotate. This movement of the cam is converted into translation of a pin in a plunger via a cable mechanism. The pin is located such that is causes an obstruction to the rotation of the standing handle when the cam is not actuated as shown in left side of FIG. 8b. When the cam is actuated, the movement of pin removes the obstruction from the rotating handle, which disables the standing mechanism lock as shown in right side of FIG. 8b. This design of the cam is simple and easy to manufacture. The design is incorporated on both left and right side of the frame. This ensures that only when the knee support is placed properly, both cams get actuated releasing the pin which obstructs the standing handle. Apart from the safety lock at the knee support, an additional lock at the handle has been incorporated to increase safety of the user in case the standing mechanism has been actuated accidentally even when the knee support has been placed, say by a third person. It has been designed such that only actuation of both the side standing handles h1 simultaneously disengages the safety lock and allows the user to get into standing position as shown in FIG. 9, thus making the standing a deliberate action on the part of the user. A small angle of rotation is provided on the handle h1 by pivoting it to the frame of the handle as shown by a in FIG. 9. When the user pushes this handle h1, the small movement of the handle is used to actuate a pin mechanism via a cable mechanism. The pin mechanism is attached to handle frame and an obstruction plate is attached to the main frame such that direct rotation of the handle causes the pin to obstruct with this plate as shown by b in FIG. 9. When the handle is actuated at h1, first the pin mechanism is actuated which no longer remains an obstruction to the rotation of the handle. By this movement of the handle h1 both sides, the standing lock is deactivated. The pin and obstructing plate are also designed such that when the user comes from standing to sitting position, the pin automatically gets into the locked position. This is accomplished by using the obstructing plate in a slanted manner which allows the pin to slide automatically.

[0046] An alternate mechanism configuration for providing an extra safety lock at the standing handle apart from the one at the knee support is explained below: The armrest is attached to the backrest and has a plate attached such that it forms an obstruction to the rotation of the standing mechanism actuating handle as shown in the FIG. 7. To enable the standing mechanism the armrest has to be moved out and then the standing handle can be actuated. The armrest could be moved upwards, sideways or completely removed. Also, the stopper could be designed as a one way lock which forms an obstruction while getting into standing position but doesn't obstruct during the reverse action of the handle for getting into the sitting position.

[0047] As described and disclosed above, in one aspect the invention is disclosing a standing wheelchair. It typically has a chassis having a first end and a rear end. A front wheel connected to the front end of the chassis and a pair of rear wheels supporting the wheelchair. A pivotable seat means of a first link (ab), the said seat pivotable between a generally horizontal seated position and an angled standing position, and having a seating surface and a backrest means of a second link (cd), such that (ab), (bc), (cd) and (da) form a four bar parallelogram link means. It includes a driver dyad means comprising of four links (be), (ef), (fg) and (bg) which is adapted to actuate the said 4-bar mechanism. The arrangement has a pair of side handle actuator means, each handle actuator means connected rigidly to link (ef) of the driver dyad means and cooperatively associated with the 4-bar link means for actuating the seat means between the seated position and standing position. For the purpose of safety of the user, a lockable knee support means is attached to the front end of the said seat means moveable between a lock state and open operational state. To ensure the handled is used only when necessary by the user, a pair of side interlocking cam means, each interlocking cam means coupled to the knee support means and the corresponding side handle actuator means for causing the said handle actuator means to move only when the knee support means is in lock state.

[0048] In another aspect the standing wheelchair is disclosed above is such that when length of link (ad) is equal to length of link (bc), a parallelogram is formed. This is ideal design for the four link mechanism to operate the wheelchair safely.

[0049] In another aspect the standing wheelchair is disclosed above is such that it includes additional interlocking mechanism which is a locking pin, a plunger and a cable means such that the locking pin is selectively extending into and away from the handle actuator means, thereby corresponding to lock state and free operation state of the handle actuator means. The locking pin ensures that there is an intentional operation of the handle mechanism by the user and not an accidental operation.

[0050] In another aspect the standing wheelchair has another interlocking means comprising of a moveable armrest and a plate attached to the armrest means which is in turn attached to the backrest means, the said plate arranged in the motion pathway of the handle actuator means, such that the armrest along with the fixed plate extends into and away from the handle actuator means motion pathway, thereby correspondingly creating a lock state and free operate state of the handle actuator means with a locking pin selectively moving towards and away from the plate.

[0051] In another aspect the standing wheelchair includes another interlocking means comprising of a stopper means to create a lock state and free operate state of the handle actuator means.

[0052] The description is given for the understanding of the invention and thereby the embodiments do not limit the scope of the invention. The variations are within the scope of the invention.