GB2284756A

GB2284756A - Elevator mechanism for a chair

Info

Publication number: GB2284756A
Application number: GB9424503A
Authority: GB
Inventors: Dale Roger Lloyd Harding
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-12-08
Filing date: 1994-12-05
Publication date: 1995-06-21
Anticipated expiration: 2014-12-05
Also published as: GB2284756B; GB9424503D0; GB9325150D0

Abstract

An elevator mechanism for use in association with a chair comprises a generally rectangular base frame (1) connected via a pair of lateral pivoting linkages (2) to a support member (4). The support member (4) is provided at each end with fixing brackets (5) for securement to the underside of the seat portion of the chair. A drive unit (7) is pivotally connected to the base frame (1) and includes an extensible ram (8) which acts upon the support member (4). The support member (4) is adjustable in length to permit the mechanism to be used with a wide range of chairs. <IMAGE>

Description

Title: Elevator Mechanism for a Chair This invention relates to an elevator mechanism for a chair.

It is known for the elderly or infirm to use chairs incorporating an elevator mechanism to assist such a person in getting up and leaving the chair. Typically, such a mechanism will act to raise the seat of the chair and to tip the seat forward. Likewise, when the user wishes to sit down, the chair may first be raised to the elevated position, the user then sits in the chair, and the chair is then lowered to the normal position. The operation of the chair is usually controlled using a unit attached to, or housed in, one of the chair's arms.

Conventional elevator chairs of the type described above suffer from the disadvantage that they are relatively expensive, and hence beyond the means of many of the people for whom such chairs would be of greatest benefit.

There has now been devised an elevator mechanism for use in association with a chair which overcomes or substantially mitigates this disadvantage.

According to the invention, there is provided an elevator mechanism for use in association with a chair, the elevator mechanism comprising a support member adapted for fixing to the underside of the seat portion of the chair, a reaction member positioned, in use, below the support member and adapted for engagement with the ground, and drive means adapted to drive the support member upwards relative to the reaction member, wherein the support member is adjustable in length.

The elevator mechanism according to the invention is advantageous primarily in that the adjustability of the support member enables the mechanism to be fitted to a wide range of conventional chairs. Conventional chairs may thus be converted into elevator chairs simply and at relatively modest expense.

Preferably, the support member is in the form of a rail, provided at each end with means, such as brackets, for fixing to the underside of the chair.

Most preferably, the support member is a tubular rail, and is adjustable in length by means of a smaller tube slidable within the tubular rail in a telescopic action. A bracket is preferably provided at the free end of the smaller tube. Most preferably, such a smaller tube is provided in both ends of the tubular rail.

It is preferred that the upward motion of the support member relative to the reaction member is accompanied by a certain degree of forward tipping motion of the chair.

The invention will now be described in greater detail, by way of illustration only, with reference to the accompanying drawings, in which Figure 1 is a side view of an elevator mechanism according to the invention for use in association with a conventional armchair; Figure 2 is a view along the arrow A in Figure 1; Figure 3 shows a base frame forming part of the mechanism of Figure 1 in (a) plan view, (b) section along the line X-X, and (c) side elevation; Figure 4 shows a pivoting frame forming part of the mechanism of Figure 1 in (a) plan view, and (b) side elevation; Figure 5 shows a support member forming part of the mechanism of Figure 1 in (a) underside plan view, (b) along the arrow B, and (c) section along the line Y-Y; Figure 6 shows a sliding telescopic rail forming part of the mechanism of Figure 1 in (a) front elevation, and (b) end elevation;; Figure 7 shows a fixing bracket forming part of the mechanism of Figure 1 in (a) plan view, (b) side elevation, and (c) end elevation; and Figure 8 shows views similar to Figures 7(b) and (c) of an alternative form of fixing bracket.

Referring first to Figures 1 and 2, an elevator mechanism intended for fitting to the underside of the seat portion of a conventional armchair has a base frame 1 connected via a pair of lateral pivoting linkages 2,3 to a support member 4. The support member 4 is provided at each end with fixing brackets 5,6 for securement to the underside of the seat portion of the armchair.

An electrical drive unit 7 is pivotally connected to the base frame 1 and includes an extensible ram 8 which acts upon the support member 4.

The drive unit 7 is a DYMAT Type E linear drive motor unit, supplied by Dewert Antriebs- und Systemtechnik GmbH & Co KG, Weststrasse 1, D-32378 Kirchlengern, Germany.

As shown in Figure 3, the base frame 1 comprises a pair of side rails 31,32, a front rail 33 and a rear rail 34 spaced somewhat inwardly from the rearmost terminal ends of the side rails 31,32.

The rear rail 34 is somewhat shorter in length than the front rail 33, and the side rails 31,32 are bent such that base frame 1 is somewhat narrower at the rear than at the front. The rails 31-34 are of square section steel tubing and are joined by welding. An upstanding apertured plate 35 is disposed near the centre of the rear rail 34 (see Figure 3(b)). Towards the rear of the base frame 1, forward of the rear rail 34, there are provided two upstanding plates 36,37, these plates being welded to the inward sides of the side rails 31,32.

Referring now to Figure 5, the support member 4 comprises a square section steel rail 41 with, spaced somewhat inward of the ends of the rail 41, downwardly depending support limbs 42,43 of steel sheet. The longitudinal axis of each support limb 42,43 is inclined slightly to the perpendicular to the face of the rail 41 to which the support limbs 42,43 are welded.

The pivoting linkages 2,3 comprise a pivoting frame 9, shown in Figure 4. The pivoting frame 9 comprises main pivot rails 21,22 connected by a front cross-member 23 and an intermediate crossmember 24. The intermediate cross-member 24 is raised from the plane of the frame 9 by two short lengths of steel sheet 25,26 to prevent interference with the drive unit 7 and the ram 8.

Referring once again to Figure 1, the main pivot rail 21 is pivotally connected at one end to the upper end of the upstanding plate 36, and at its other end to the lower end of the support limb 42. The pivoting linkage 2 is completed by a series of three pivoting links 44,45,46 connecting the lower end of the upstanding plate 36 with the upper end of the support limb 42, the central link 45 also being pivotally connected to the main pivot rail 21. All pivotal connections are by means of suitable bolts, and the pivoting linkage 3 on the other side of the mechanism is identical in form to that described.

The electrical drive unit 7 is pivotally mounted about the apertured plate 35 and the terminal end of the ram is held pivotally between a pair of downwardly depending plates 47,48 on the underside of the support rail 41. Electrical power is fed to the drive unit 7 via a mains cable (not shown). A control cable 51 leads to a press-button control unit (not shown).

Slidably mounted within the support rail 41 are a pair of rightand left-handed telescopic rails comprising smaller section steel tubes 60 welded to plates 62 (see Figure 6). Figure 6 shows one of the telescopic rails, the other being identical, save for being of opposite handedness. The fixing brackets 5,6 are secured to the plates 62 by bolts 64.

The fixing brackets 5,6 are shown in detail in Figure 7 (again one member of a right- and left-handed pair of brackets 5,6 is shown) and include L-section arms 73 which, in use, are secured to appropriate points on the underside seat portion of a chair.

The arms 73 may for example be screwed to the underside of the wooden side rails of the chair's frame.

Each arm 73 is welded at one end thereof to a bracket plate 71.

The plates 62 and the bracket plates 71 are provided with series of apertures (69,79 respectively) to permit the fixing brackets 5,6 to be fitted to the plates 62,63 in the most appropriate position for the particular armchair with which the mechanism is used. In the alternative form of fixing bracket shown in Figure 8, the L-section arm is disposed differently, such that the face of the arm which is fitted to the chair is aligned with the lower edge of the bracket plate. Further adjustment for fitting to a wide range of chairs is possible by virtue of the fact that the sliding rails 60 may be inserted into the ends of the support rail in any one of four orientations.

The telescopic action of the sliding rails 60 within the support rail 41 enables the elevator mechanism to be fitted to a wide range of conventional chairs. The telescopic rails 60 are locked in position relative to the support rail 41 by means of locking bolts 75,76 which locate in threaded nuts 77,78 welded to the support rail 41. The bores of the nuts 77,78 coincide with holes in the support rail 41 such that the shanks of the locking bolts 75,76 pass through the holes and bear against the telescopic rails 60.

Figures 1 and 2 show the elevator mechanism in an elevated position. Retraction of the ram 8 causes the support member 4 to lower relative to the base frame 1, and as it does so the Lsection arms 73 of the fixing brackets 5,6 to rotate anticlockwise (as viewed in Figure 1). In the lowered position, the seat of the chair is in its normal position, and the base frame 1 rests on the floor or just above it. In the latter case, the elevator mechanism is effectively suspended from the underside of the chair seat.

If a user seated in the chair wishes to stand up, he or she actuates the elevator mechanism by means of the control unit.

The drive unit 7 extends the ram 8, causing the mechanism to move towards the position shown in Figures 1 and 2. If the base frame 1 is not already in contact with the floor, it is driven downwards until it makes such contact. Then, continued extension of the ram 8 causes the support member 4 to rise up and the fixing brackets 5,6 to rotate clockwise (as viewed in Figure 1).

This has the effect of raising the whole chair and tipping it forwards, from which position the user can more easily stand up and leave the chair.

Claims

1. An elevator mechanism for use in association with a chair, the elevator mechanism comprising a support member adapted for fixing to the underside of the seat portion of the chair, a reaction member positioned, in use, below the support member and adapted for engagement with the ground, and drive means adapted to drive the support member upwards relative to the reaction member, wherein the support member is adjustable in length.

2. An elevator mechanism as claimed in Claim 1, wherein the support member is in the form of a rail provided at each end with means for fixing to the underside of the chair.

3. An elevator mechanism as claimed in Claim 2, wherein the support member is a tubular rail, and is adjustable in length by means of a smaller tube slidable within the tubular rail in a telescopic action.

4. An elevator mechanism as claimed in Claim 3, wherein a smaller tube is slidable in each end of the tubular'rail.

5. An elevator mechanism as claimed in any preceding claim, wherein the reaction member is a base frame comprising a front rail, a rear rail and two side rails.

6. An elevator mechanism as claimed in Claim 5, wherein the rear rail is of shorter length than the front rail such that the base frame is somewhat narrower at the rear than at the front.

7. An elevator mechanism as claimed in any preceding claim, wherein the support member and the reaction member are connected by pivoting linkages.

8. An elevator mechanism as claimed in any preceding claim, wherein the drive means includes an electric motor.

9. An elevator mechanism as claimed in any preceding claim, wherein the drive means includes an extensible ram which acts upon the support member.

10. An elevator mechanism for use in association with a chair, substantially as hereinbefore described and as illustrated in the accompanying Figures.