Wheel chair with extensible wheel base to facilitate ingress and egress

Abstract

According to the invention, there is provided a wheelchair having a propelling wheel, the said wheel being held in a wheel holder which in turn is mounted both pivotally and slidingly from a first forward position to a second backward position with respect to the seat and backrest of the wheelchair, a lock means being provided which is adapted to lock the said wheel holder in either of the said extreme positions.

Description

BACKGROUND OF INVENTION

The present invention relates to a wheelchair, in particular to a wheelchair having two rear propelling wheels and either two detachable or folding armrests or only one such armrest, while the second remains fixed.

The invention is especially, but not exclusively, useful with respect to wheelchair constructions for the kind of user who is capable of propelling the said wheelchair manually by rotating the wheels with his hands but has great difficulty in transferring himself to another chair, car or bed, and due to the weakness of limbs is unable to stand up or sufficiently raise his torso.

The advantage of such manually operated wheelchairs resides in its allowing the user a maximum of independent mobility, as can be expected under such circumstances.

The disadvantage of such manually operated wheelchairs for said kind of user is that due to the fact that the propelling wheel does not permit the user to slide across the wheelchair, which prevents the user of the chair from moving in a lateral direction.

The object of the present invention is to provide a manually operated wheelchair which is designed to overcome the aforementioned problem.

SUMMARY OF INVENTION

In the following description the said "first" position will be referred to as "transporting position," since in that position the wheelchair can be used to transport its rider from one place to another. The said "second" position will be referred to as "transferring position," since in it, the rider can transfer himself from the wheelchair to another means of support, say another chair, the bed or the like.

In a practical embodiment of the invention, the holder comprises an arcuate guide which is pivotally attached to the rear of the chassis of the wheelchair and which is slidingly displaceable in relation to the said chassis, the said propelling wheel being rotatably attached to the wheel holder and an operating pulling-pushing handle being provided for moving the wheel holder and the propelling wheel between said extreme positions.

According to a further feature of the invention, the said lock is comprised of a hinge pivotally connecting the lock to the wheelchair body, a latch locking said wheel holder in either of its extreme positions, and an operation release handle for releasing said wheel holder from the catch of the latch.

Since the novel wheelchair is opened in its transferring position on the seat side by locating the propelling wheel at the rear of the seat, it is possible to provide a convertible armrest which is transformed into a sliding board by pivoting the armrest to the horizontal position.

According to this feature of the invention the convertible armrest has a rigid plane surface on its inner side and hinges on its seat level so as to be adapted to be swung from the vertical armrest position to the horizontal sliding position, a lock being provided for locking it at its armresting position.

This part of the invention makes unnecessary the use of a special additional sliding board separate from the wheelchair, and is intended for use by the invalid rider of the wheelchair, enabling that person to slide from the chair onto another support.

Further features and advantages of the invention will be apparent from the description below.

SHORT DESCRIPTION OF DRAWINGS

The invention is herein described with reference to the accompanying drawings which illustrate, for purposes of example only, one form of wheelchair constructed in accordance with the invention.

In the drawings:

FIG. 1 is an elevational side view illustrating such a wheelchair while its propelling wheel is locked in the transporting position.

FIG. 2 is a like view illustrating the propelling wheel in a position intermediate the two extreme positions.

FIG. 3 is another elevational view illustrating the wheel in the backward locked transferring position, and the construction of the convertible armrest.

FIG. 4 is a fractional perspective view illustrating the construction and operation of the wheel locating arrangement while it is in the midposition.

FIG. 5 is a partial perspective view illustrating the wheelchair in its transferring position, with the wheel locked in its backward location and the armrest converted to its horizontal sliding position.

FIG. 6 is a fractional perspective view illustrating the construction of the armrest pivoting and mounting arrangement.

FIG. 7 is a perspective view illustrating the embodiment of wheelchair in which both rear wheels and both armrests are pivotable.

DESCRIPTION OF PREFERRED EMBODIMENT

The wheel holder designated as a whole by the numeral 1 is comprised of a tubular member 2 (see FIG. 4), a fork 3 carried by the tubular member 2 and connected to it as by welding, having drilled holes 4 at its lower end. At its upper end the tubular member 2 carries a hollow cross piece 5, as by welding. Cross piece 5 carries on its inner end i.e., that side which faces the wheelchair, e.g. by having welded to it, an arcuate guide rail 6 shaped of flat metal and being curved with holes 4 as centre, handle 7 is affixed to cross piece 5, e.g. being welded to it, on its upper side. The handle 7 includes a padded grip 8 on its upper end (see FIGS. 1 and 2). An ear or bracket 14 is carried on the rearwardly extending bar 15, forming part of the chassis being affixed by shackles 17.

The fork 3 rides on the bar 15, a pin 16 passes through holes 4 and the bracket 14. The arcuate guide 6 is slidingly connected to the chassis by means of a bolt 18 which passes through a spigot 19 extending from the chassis. The guide 6 is positioned on the inner side with respect to the wheelchair body.

Said wheel holder 1 is mounted swingingly on the wheelchair body, and therefore by pushing and pulling said handle 7, the wheel holder 1 moves about its centre 4, its arcuate guide 6 sliding on body pivot 19 along its arcuate slot 9 between the closed ends 10 and 11 of the slot 9, its movement being limited by the bolt 18. The propelling wheel 20 being carried on the cross piece 5 by a pin 22 which passes also through the wheel hub 21, can be moved backward and forward between its two extreme positions carried by the wheel holder 1.

For the purpose of locking the wheel 20 in either of its said extreme positions a wheel lock is provided.

The wheel lock 23 comprises a pawl 24 connected by a curved arm 24' to an eye 25. From arm 24' extends releasing handle 26.

The handle bar 26 has a padded grip 27 on its free end. The lock 23 is mounted pivotally by means of the eye 25 on the spigot 19 opposite the arcuate guide 6 and is joined together with the guide 6 by the bolt 18.

While the propelling wheel 20 is in its forward transporting position, pawl 24 is engaged in an appropriate catch 12 on the rear part of the arcuate guide 6 holding the wheel 20 in said position. Respectively, when wheel 20 is in its backward transferring position, pawl 24 engages over the front end 13 of the arcuate guide 6.

As can be learned from FIGS. 1 and 3, while the propelling wheel 20 is in either of its extreme positions, the wheel holder member 2 is inclined about 30.degree. in a forward direction or a backward direction relative to the vertical. Therefore when releasing handle 26 is lifted from either engaged position, member 2 assumes a vertical position due to the force generated by the weight of the wheelchair body and the user. While member 2 is in the vertical position, wheel 20 is in the midway position between its two extremes. On the other hand, when the wheel locating handle 7 is either pushed or pulled from its midway position toward one of its extreme positions, the locking pawl 24 is engaged by the appropriate catch, either 12 or 13, by the force of the weight of the releasing handle 26 as suggested in FIGS. 1, 2 and 3.

These two features of the invention discussed above, i.e., the gravitationally self changing propelling wheel being moved to the half way position by only lifting the releasing handle 26, and the gravitationally self locking of the latch 24 being achieved by only pulling or pushing the wheel locating handle 7 to desired position, simplify the construction of the wheelchair according to the invention without special need for springs or other problematic mechanisms, and which is even more important -- these features enable the user to operate the wheel location by two simple movements of one hand, as described above.

The convertible armrest indicated as a whole by the numeral 30 comprises a tubular bent frame 31 carrying on its inwardly facing side, (in respect to the seat 28), a plane surfaced rigid sheet 32, of metal or hard plastic. The frame 31 is provided at its lower corners 33 and 34 with two hinge members 36 and 37 of any known kind co-operating with two corresponding hinge members 38 and 39 provided on two tubular members 40 and 41, which are mounted adjustably and detachably by means of two bolts 42 and 43 in two sleeves 45 and 46 carried on the wheelchair body e.g. being welded thereto. A spring operated lock 50 positioned on the chassis, in register with point 43 secures the rear upper corner of the armrest 30 in its vertical armresting position.

The members 40 and 41 have a plurality of adjustment holes 44 (see FIG. 7) and the sleeves 45 and 46 have, respectively, one corresponding hole 47 and 48. While armrest 30 is in its horizontal sliding position, the sliding surface 32 has to be on the same level with the sitting plane which is not always identical with the wheelchair seat surface 28, because some users employ seat cushions to prevent decubitus ulcers. The plurality of holes 44 enables the selection of the appropriate surface level of the armrest sheet 32.

The mode of operation of the novel wheelchair will be apparent from the following description.

Transfer of wheelchair rider to another (stationary) seat

The wheelchair is in transporting position occupied by the user preparing to transfer himself to another seat. The wheelchair is brought near the desired stationary seat. The user, or his assistant, lifts the releasing handle 26 whereupon the propelling wheel 20 drops to the midposition, the operator then pushes back the wheelplacing handle 7 until the releasing handle 26 falls into its lower position signifying that the pawl 24 is in engaging position i.e., the wheel 20 is locked in its backward position behind seat 28 and backrest 29. Then the operator releases the armrest 30 from its vertical closed position, the operator pivots the armrest 30 to the horizontal position until it rests on the edge of the desired seat. The wheelchair is then prepared for transferring.

Transfer from a stationary seat onto the wheelchair

The wheelchair is unoccupied and a user is preparing to transfer himself onto the wheelchair. The wheelchair is brought to transferring position in the same way as described above and, after the transferring operation is completed, the operator pivots the armrest 30 to its vertical position until the armrest 30 is engaged by the lock 50. Then the operator lifts the releasing handle 26, the propelling wheel 20 drops to its midposition, wheel locating handle 7 is pulled forward by the operator until the releasing handle 26 drops to its lower position signifying that the pawl 24 is engaged i.e. the wheel 20 is locked in its forward position, and the wheelchair is ready in its transporting position.

It will be appreciated that the above described construction could be used in part only, for example, without the convertible armrest but with a conventional detachable armrest, or with a convertible armrest provided to fit a so-called "car transit chair," i.e., a wheelchair having small wheels only, and intended for operation by an assistant. It will also be appreciated that characteristic parts of the above described invention could be mounted on a conventional wheelchair even by the consumer, since these parts could be prepared for fitting those wheelchairs, without disturbing their positive properties, e.g. their collapsibility or stability. These aforementioned variant applications may be made within the scope of the invention as defined in the following claims.

Many other changes, variations and applications of the illustrated embodiment may be made within the scope of the invention, as defined in the following claims.

Claims

What is claimed is:

1. A wheelchair comprising:

a chassis;

a seat for a rider, mounted on said chassis;

first and second rear propelling wheels disposed on opposite sides of said chassis;

a wheel hub, having mounted thereon one of said rear propelling wheels;

a pivot arm pivotably connecting said wheel hub to said chassis at a fixed pivot point thereon;

an arcuate guide connected to said wheel hub and slideably engaging said chassis at a point on said chassis above said pivot point, said arcuate guide defining an arcuate path of said wheel hub about said pivot point between two opposite end positions of said arcuate guide;

said pivot point being positioned on said chassis at a point substantially vertically below a midpoint along said arcuate path between the two opposite end positions; and

hub locking means for locking said wheel hub in either of the two end positions of the arcuate path.

2. A wheel chair according to claim 1, further including:

a second wheel hub having mounted thereon the other of said rear propelling wheels;

a second pivot axis pivotably connecting said second wheel hub to said chassis at a second fixed pivot point thereon;

a second arcuate guide connected to said second wheel hub and slideably engaging said chassis at a point on said chassis above said second pivot point, said second arcuate guide defining an arcuate path of said second wheel hub about said second pivot point between two opposite end positions of said second arcuate guide;

said second pivot point being positioned on said chassis at a point substantially vertically below a midpoint along said arcuate path of said second wheel hub between the two opposite end positions; and

second means for locking said second wheel hub in either of the two end positions of the arcuate path thereof.

3. A wheelchair according to claim 1, further including:

first and second armrests attached to opposite sides of said chassis;

a rigid plane surface disposed on one of said armrests on the side thereof facing said seat, said one of said armrests being hinged to said chassis to be swingable from a vertical position to a horizontal position; and

armrest locking means being provided for securing said armrest in either the vertical or horizontal position thereof;

said pivot point being disposed and said pivot arm and said arcuate guide being of such size that when said wheel hub is in one of the end positions of the arcuate path, said armrest is swingable into the horizontal position thereof in a plane below the uppermost vertical extention of said one of said rear propelling wheels without contacting said one of said rear propelling wheels.

4. A wheelchair according to claim 2, further including:

first and second armrests attached to opposite sides of said chassis;

first and second rigid plane surfaces disposed on respective ones of said armrests on the sides thereof facing said seat, each of said armrests being hinged to said chassis to be swingable from a vertical position to a horizontal position; and

first and second armrest locking means being provided for securing respective ones of said armrests in either the vertical or horizontal positions thereof;

said pivot points being so disposed and said pivot arms and said arcuate guides being of such size that when respective ones of said wheel hubs are in one of the end positions of the respective arcuate paths, the respective ones of said armrests are swingable into the horizontal positions thereof in planes below the uppermost vertical extensions of the respective ones of said rear propelling wheels, without contacting the respective ones of said rear propelling wheels.