GB2044607A

GB2044607A - Adjustable seat back

Info

Publication number: GB2044607A
Application number: GB7909440A
Authority: GB
Original assignee: DIMMOCK FURNITURE CO Ltd
Current assignee: DIMMOCK FURNITURE CO Ltd
Priority date: 1979-03-17
Filing date: 1979-03-17
Publication date: 1980-10-22
Also published as: GB2044607B

Abstract

A chair in which the angle of the back 21 can be adjusted relative to the seat part 11 under the control of a cam 30. Arms 16, which are connected to back 21, are received in a groove in each cam, the base of the groove providing the cam surface. <IMAGE>

Description

SPECIFICATION Improvements relating to seating This invention relates to adjustable seating particularly, but not exclusively, for use by geriatric patients.

An object of the invention is to provide a new and improved adjustable seating.

According to the invention we provide an adjustable seating comprising a ground engageable frame portion, a seat part and a back part, means mounting the seat and back parts of the frame portion and permitting adjustment of the angle of the back part relative to the seat part and cam means to control said adjustment.

The back part may be pivotally mounted at or adjacent its lower end for pivotal movement relative to the seat part and provided with at least one control arm extending generally forwardly adjacent the seat part and there being a manually rotatable cam engaged between the control arm and a fixed portion of the seating whereby the distance between the fixed portion and the portion of the control arm engaged by the cam can be varied thereby adjusting the angle of inclination of the back part.

The back part may comprise a backboard mounted on one arm of a two-armed lever, the other arm providing said control member and the lever being pivotally mounted relative to the ground engageable frame at the junction between the arms.

The lever may be pivotally mounted on a seat board.

The seatboard may provide said fixed portion.

Preferably two such levers are provided one on each side of the back and seat boards and each may be engaged with a cam, the cams being carried on a shaft.

The back board may be adjustable longitudinally of said one arm of the or each lever.

The conformation of the or each cam may be such as to maintain the or each cam in any one of a plurality of desired positions.

The invention will now be described in more detail by way of example with reference to the accompanying drawings wherein:- FIGURE 1 is a fragmentary diagrammatic crosssectional view through a seating embodying the invention, FIGURE 2 is a rear view of the part of the seating shown in Figure 1, FIGURE 3 is a side elevation, to an enlarged scale, of the cam of Figure 1, and FIGURE 4 is a section on the line 4-4 of Figure 1.

Referring now to the drawings, an adjustable seating comprises a ground engageable frame portion, not shown, upon which a seat board 10 is mounted.

The seat board 10 is provided with a conventional foam filled upholstered seat part 11. At the rear of the seat board 10 a frame member 12 is secured to a reduced cross-section part of the seat board and carries a pivot 13 by which a pairoftwo-armed levers 14 are pivotally mounted on the seat board. Each lever 14 is made from steel tube and comprises a first arm 15 and a second arm 16. At their upper ends the first arms 15 are bent through 90 to form a transversely extending part 17 and the parts 17 may be separate from each other or integral with each other in which case both arms 16 and both arms 15 and the common transversely extending part 17 are bent from a single length of tube.

A back board 18 is adjustably mounted on the arms 15 by virtue of being provided with a plurality of brackets 19 with any desired one of which transversely extending part 17 can be engaged. A resilient webbing material 20 is fixed to the back board 18 in the region of the brackets 19 to prevent inadvertent disengagement of the brackets 19 on the transversely extending part 17.

The back board 18 is provided with a conventionally upholstered foam filled back part 21 on its front surface whilst on its rear surface it is provided with a peripheral frame 22 and a pair of guide members 23 which are spaced so as to receive the arms 15 therewithin the guiding clearance.

Secured to the underside of the seat board 10 are a pair of blocks 24 to which a pair of trunnion members 25 are secured. The trunnion members 25 are adapted to receive in a channel section portion 26 thereof a shaft 27 carrying at one end a transversely extending lever 28 having a knob 29. The width of the channel section part 26 is such as to snugly engage the shaft 27 whilst the depth of the channel part 26 is considerably greater than the diameter of the shaft 27 so as to permit vertical sliding movement of the shaft 27 for a purpose to be hereinafter described.

The shaft 27 carries a pair of cams 30 having the configuration shown best in Figures 3 and 4. That is to say each cam 30 has a grooved lower portion 31 the base of the groove having four generally part cylindrical portions indicated at a - d whilst the upper part of the cam 30 is not recessed and has a smoothly curved surface 32. The upper part 32 is adapted to engage an underneath portion 33 of the seat board 10 whilst the lower part 31 is adapted to engage the associated arm 16 of the levers 14.

In order to prevent inadvertent forward tilting of the back board 18 a hanger member 33 of generally U configuration having inturned upper end parts 34 which are received in an aperture 35 in the cam 30 are provided which, as best shown in Figure 4, prevent the arm 16 becoming disengaged from the lower part 31 of the cam 30.

Because of the part cylindrical nature of the portions a - d of the cam engaged with the arm 16 the cam is retained in position with the desired one of the portions a - d engaged with the arm 16. This can be aided by providing corresponding planar portions on the upper portion 32 of the cam.

When it is desired to adjust the angle of inclination of the back part the knob 29 is grasped manually and the lever 28 pivoted in appropriate direction. For example when it is desired to move the back from its most upright position shown in full line in Figure 1 progressively to its most inclined position, as shown in dotted line in Figure 1 the lever 28 is pivoted from the full line position from an anti-clockwise to the dotted line position and the arm 16 is caused progressively to move from engagement with the portion through the portions c andb to the portion a of the cam.

In orderto permit this rotation of the cam over "peaks" between adjacent cam partions a - d the shaft 27 is permitted to slide in a vertical direction in the channel section portion 26 of the trunnions 25, this being permitted by virtue of a great depth of the channel section portion than the diameter of the shaft.

Of course movement of the back part in the opposite directions is achieved by a reverse direction movement of the lever 28.

If desired the cam may be provided with more or fewer sections than the four described hereinbefore and their angular relationship may be such as to achieve a greater or lesser degree of adjustment of the back part.

If desired the back part may be provided with wings and the seating may be provided with the lumbar adjustment described in our co-pending application No.11724/77 cog. No.41142/77. (Serial No.1565014).

Claims

1. An adjustable seating comprising a ground engageable frame portion, a seat part and a backpart, means mounting the seat and back parts of the frame portion and permitting adjustment of the angle of the back part relative to the seat part and cam means to control said adjustment.

2. Seating according to Claim 1 wherein the back part is pivotally mounted at or adjacent its lower end for pivotal movement relative to the seat part and provided with at least one control arm extending generally forwardly, adjacent the seat part and there being a manually rotatable cam engaged between the control arm and a fixed portion of the seating whereby the distance between the fixed portion and the portion of the control arm engaged by the cams can be varied thereby adjusting the angle of inclination of the back part.

3. Seating according to Claim 2 wherein the control arm extends forwardly beneath the seat part.

4. Seating according to Claim 2 or Claim 3 wherein the back part comprises a backboard mounted on one arm of a two armed lever, the other arm providing said control arm and the lever being pivotally mounted relative to the ground engageable frame at the junction between the arms.

4. Seating according to Claim 2 or Claim 3 wherein the back part comprises a backboard mounted on one arm of a two armed lever, the other arm providing said control member and the lever being pivotally mounted relative to the ground engageable frame at the junction between the arms.

5. Seating according to Claim 4 wherein the lever is pivotally mounted on a seat board.

6. Seating according to Claim 5 wherein the seatboard provides said fixed portion.

7. Seating according to any one of Claims 4 to 6 wherein two such levers are provided one on each side of the back and seat boards and each being engaged with a cam, the cams being carried on a shaft.

8. Seating according to any one of Claims 4 to 7 wherein the back board is adjustable longitudinally of said one arm of the or each lever.

9. Seating according to any one of the preceding claims wherein the conformation of the or each cam is such as to maintain the or each cam in any one of a plurality of desired positions.

10. Seating substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

New claims or amendements to claims filed on 19.2.80.

Superseded claims 1, 2, 3,4.

New or amended claims:- 1,2,3,4.

1. An adjustable seating comprising a ground engageable frame portion, a seat part and a back part, means mounting the seat part and the back part on the frame portion, the back part being pivotally mounted at or adjacent its lower end for pivotal movement relative to the seat part and provided with at least one control arm extending generally forwardly adjacent the seat part, and there being a rotatable cam located between the control arm and a fixed portion of the seating whereby the angle of inclination of the back part relative to said fixed portion can be adjusted, the fixed portion and the control arm bearing on the cam.

2. Seating according to Claim 1 wherein the cam is adapted to be manually rotatable.

3. Seating according to Claim 1 or Claim 2 wherein the control arm extends forwardly beneath the seat part.