Invalid Chair

Abstract

An invalid chair having a seat back hinged to the back of the seat and a lower frame hinged to the front of the seat to form an extensible assembly which is pivoted to a main support frame, the seat being spring loaded in a direction to extend the assembly of frames so that an invalid is assisted from the seat on to his feet, the assembly also being positionable in a recumbent position so that the chair functions as a bed.

Description

This invention relates to a chair which is suitable for general use, but particularly for use by invalids who have difficulty in moving their joints and in exercising their limbs, and may include, but is not limited to a wheel chair.

It is known that arthritics have great difficulty in changing position, for example from a seated position to a standing position, and the main object of this invention is to provide a chair wherein at least some of the weight of a user is counterbalanced so that the chair will assist a user in changing from a seated to a standing position.

The invention may in one of its forms consist of a chair having a seat frame, a back frame hingedly connected to the rear end of the seat frame, a lower frame hingedly connected to the front end of the seat frame to form with the seat and back frames an extensible assembly, link means further interconnecting said frames, a main support frame, hinge means hingedly connecting one of the frames of said extensible assembly to the main support frame, and spring means operatively connecting one of the frames of said extensible assembly to the main frame and urging the frames of said extensible assembly towards their relatively extended positions. A chair constructed according to this invention may be operated with very little effort by the body movements of a user, and the spring means will be of assistance to a user moving from a seated to a standing position, as the frames which constitute the extensible assembly move correspondingly from a relatively retracted to a relatively extended position.

It is desirable for an arthritic or other invalid to be able to exercise legs and ankles while in a seated position, but the patient's feet should be supported by a footrest. It is of course desirable that the footrest should not be moveable when the patient is in a standing position, and further desirable that the footrest position should be as low as possible so that the step height is small.

To achieve these objects the invention may although not necessarily include as one of its further features a relatively moveable pressure plate on the lower frame engaged by a pressure imparting member on a link hinged to the seat frame, the pressure imparting member however being moved out of engagement with the pressure plate as the seat frame is lowered from an extended to a retracted position.

When a patient is sitting upright in a chair it is desirable that the headrest should be in approximately the same plane as the backrest, but when the patient is lying on a support, it is desirable that the headrest should be elevated relative to the backrest, and to achieve this object this invention may include as a still further feature a headrest frame hinged to a backrest frame but arranged to be secured thereto in any one of a plurality of positions.

It will be seen that the invention may be applied either to a mobile or an immobile chair, and the mobile chair could for example be a wheelchair arranged to be operated by a patient. However, an embodiment of the invention when applied to a simple mobile chair arranged to be operated by a person other than a patient is described hereunder in some detail with reference to and is illustrated in the accompanying drawings, in which:

FIG. 1 is a diagrammatic representation of a chair with the frames of its extensible assembly arranged in a retracted position (for a patient when seated),

FIG. 2 is a corresponding diagrammatic view showing the frames of the extensible assembly arranged in an elevated extended position (for a patient when moving to or from a standing position),

FIG. 3 is a further corresponding diagrammatic view showing the frames in a horizontal extended position (for a patient in a recumbent position),

FIG. 4 is an elevation illustrating the frames and linkage mechanism of the chair,

FIG. 5 is a perspective view of the chair in its elevated extended position,

FIG. 6 is a fragmentary view of portion of the lower frame of the chair showing the pressure imparting member firstly in a position of disengagement from the pressure plate, and secondly in a position of engagement, and

FIG. 7 is a fragmentary view showing adjustment means for adjustment of the angle of the back frame relative to the seat frame.

In this embodiment a main support frame 10 supported by wheels 11 is provided with aligned main pivots 12 one on each side, the main pivots being disposed forwardly on the main frame 10, and the seat frame portion of an extensible assembly 13 is pivoted about these pivots 12 to the main frame, and supported by the pivots.

The extensible assembly 13 comprises a seat frame 16, a back frame 17 hingedly connected to the rear end of the seat frame 16 about the pivot 18, and a lower frame 19 pivotally connected to the front end of the seat frame about the pivots 20. The back frame 17 includes a headrest 21, and the lower frame 19 includes a footrest 22. This entire assembly pivots as a whole about the main pivots 12 on the main support frame 10.

A pair of seat frame-lifting levers 26 are pivoted between their respective ends on the pivots 27 on the main frame 10, the rear ends being provided with rollers 28 which engage the underface of the seat frame 16. The front ends are connected to the front ends of rearwardly and downwardly sloping lifting springs 29 (not shown in FIG. 3). The rear lower ends of the lifting springs 29 are anchored to an anchor bar 30 carried by the main frame 10, and having a position adjustment screw 31 on the end of a crank arm 32, to provide tension adjustment means which are used to ensure the lifting spring 29 correctly counterbalances the weight of a user.

The footrest 22 is hinged near its rear end to the lower frame 19 about pivots 38, the footrest having a rearwardly projecting arm 39 which is connected to a pressure imparting arm 40 by a link 41. The arm 40 is pivoted at its one end to the main frame 10 about the main pivot 12, and carries a pressure roller 42 at its lower end, the arm 40 further being connected to downward extensions 44 of the back frame 17 by the link 45, which cooperates with the seat frame 16 to form a "parallel arm" type of interconnection between the back frame 17 and the lower frame 19. As shown in FIGS. 2 and 3, this retains approximately the same relationship of the frames of the extensible assembly 13 for the upright and recumbent positions of a patient, and any required slight variation is arranged by simply deviating from the parallel conditions.

A seat back lift spring 48 connects the arm 40 to the main frame 10, and becomes extended when the arm 40 moves forwardly as shown in FIG. 3, so that a patient when in the recumbent position is assisted from that position to a sitting position by this spring. The rear face of the lower frame 19 is provided with a pressure plate 50 which is engaged by the pressure roller 42 carried on the lower end of the pressure imparting arm, the arrangement being that the pressure imparting arm prevents swinging of the footrest if the extensible assembly 13 is extended, but permits swinging of the footrest if retracted as in FIG. 1, thereby stabilizing the footrest when a patient is to move outwardly from the chair from a seated to a standing position. The linkage on the footrest is so arranged that it lays the footrest over at a comfortable angle for the feet of a patient when the chair is in any of its positions. When the upper frame is canted forward from vertical with the seat frame horizontal, the footrest is free to swing thus enabling the patient to exercise feet and legs (see FIG. 6).

The rear end of the seat frame is hinged to the upper frame as described above, and the linkage is such that the upper frame is sloping forwardly and upwardly when the extensible assembly is in its extended position but rearwardly and upwardly when it is in its reclining position. The linkage further lowers the upper frame to be substantially in the same plane as the seat frame when the chair is lowered right back for a patient to occupy a horizontal position.

When the upper frame is in a substantially horizontal position, the headrest hinged to the upper frame may be adjusted to a slightly raised position if this is desired.

It is desirable for a patient to be able to regulate the relative angle between the seat frame and the upper frame and to retain those two frames at that angle, and to achieve this a notched plate 54 is included on the back frame 17 (FIG. 7) and this is engaged by a latch 55 on a hand lever 56, the latch 55 simply moving into a notch to prevent relative movement and being released therefrom to allow relative movement as the frames vary in their angular relationship, the latch 55 automatically disengaging from its notch as the chair moves to its upstanding extended position (FIG. 2) by engaging a striker plate (not shown) on the frame 10.

To enable the extensible assembly 13 to occupy a retracted position, the main support frame 10 is provided with support brackets 57 which support the seat frame in its retracted position, and are engaged by respective complementary latches 58 (FIG. 4) coupled to release levers 59 by links 60.

In this embodiment the seat frame is provided with an aperture (not shown) disposed centrally, and the seat cushion 64 (FIG. 5) is a loose cushion positioned on the seat frame to cover the aperture, which is also provided with a lift-out panel (not shown). A shelf (not shown) is positioned on the main frame but beneath the seat frame when in its horizontal position, and this then enables the chair to be used as a commode. The arms may (if desired) be arranged to retain a table.

Claims

I claim:

1. A chair having a seat frame, pivot means connecting the rear end of the seat frame to a back frame, further pivot means connecting the front end of the seat frame to a lower frame, link means between the back frame and the lower frame limiting relative angular relationship therebetween upon tilting of the seat frame, a footstool, pivot means connecting the footstool to the lower end of the lower frame, link means between the footstool and a said frame limiting angular movement of the footstool upon tilting of the seat frame, said footstool and frames constituting an extensible assembly which in its extended position has said frames more nearly in alignment than when in its retracted position, a main support frame, main pivots between the seat frame and the main support frame, support brackets on the main frame supporting the seat frame when said extensible assembly is in its retracted position, a seat frame lifting lever, pivot means pivotally supporting said lever on the main frame, means on the lever engaging the under surface of the seat frame, a tension spring connected at its respective ends to the lifting lever and the main frame urging the seat frame upwardly and forwardly thereby in turn urging the frames of said extensible assembly towards their relatively extended positions.

2. A chair having a seat frame, a back frame, first hinge means connecting the back frame to the rear end of the seat frame, a lower frame, further hinge means connecting the lower frame to the front end of the seat frame to form with the seat and back frames an extensible assembly, link means further interconnecting said frames, a main support frame, main pivots connecting one of the frames of said extensible assembly to the main support frame, a seat frame lifting lever, pivot means pivotally supporting said lever on the main frame, means on the lever engaging an under surface of the seat frame, and spring means connected to the lifting lever and to the main frame to urge the seat frame upwardly and forwardly thereby in turn urging the frames of said extensible assembly towards their relatively extended positions said link means includes a link, first pivot means pivotally connecting the rear end of the link to a downward extension of the back frame, a second link means including a link arm pivotally connected to the seat frame and extending downwardly therefrom: further pivot means operatively and pivotally connecting the front end of the link to the link arm and including a member pivotally operatively connecting to the lower frame and to the link arm between its connections to the seat frame and to the link; the distance between said first hinge means and said further hinge means being a little greater than the distance between said first pivot means and said further pivot means so that the angular relationship between the back frame and lower frame varies by only a small amount as the extensible assembly moves from an extended to a retracted position.

3. A chair according to claim 1 further comprising support brackets secured to the main frame and positioned to support the seat frame when in its retracted position, and latch means on the seat frame and main frame cooperating to releasably retain the seat frame in its retracted position.

4. A chair according to claim 1 further comprising a pressure imparting arm, hinge means at the upper end of the pressure imparting arm hingedly connecting it to the seat frame, a roller journaled to the lower end of the pressure imparting arm, and a pressure plate extending rearwardly from the lower frame, said main pivots being between first said pivot means and said further pivot means so that the pressure plate is engaged by the pressure roller only as the frames of said extensible assembly move towards and into their extended positions.

5. A chair according to claim 4 further comprising a seat back lift spring connected at one end to said pressure imparting arm and at the other end to the rear of the main frame, said link means between the back frame and lower frame being constituted by a link, pivot means between one end of the link and said pressure imparting arm and further pivot means between the other end of the link and a downward extension of said back frame, the seat back lift spring thereby being extended by movement of the frames of said extensible assembly into their relative extended recumbent positions.

6. A chair according to claim 2 wherein the link means includes a link, first pivot means pivotally connecting the rear end of the link to a downward extension of the back frame, a second link means including a link arm pivotally connected to the seat frame and extending downwardly therefrom; further pivot means operatively and pivotally connecting the front end of the link to the link arm and including a member pivotally operatively connecting to the lower frame and to the link arm between its connections to the seat frame and to the link; the distance between said first hinge means and said further hinge means being a little greater than the distance between said first pivot means and said further pivot means so that the angular relationship between the back frame and lower frame varies by only a small amount as the extensible assembly moves from an extended to a retracted position.