GB1597474A

GB1597474A - Office chairs

Info

Publication number: GB1597474A
Application number: GB3885177A
Authority: GB
Original assignee: EVERTAUT Ltd
Current assignee: EVERTAUT Ltd
Priority date: 1978-05-12
Filing date: 1978-05-12
Publication date: 1981-09-09

Description

(54) IMPROVEMENTS IN OR RELATING TO OFFICE CHAIRS (71) We, EVERTAUT LIMITED, a British Company of Cross Street, Darwen, Lancashire, BB3 2PW, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to office chairs, for example typists' chairs, in which the seat is supported on the top of a central pillar of a pedestal. The pillar allows the seat to swivel and enables the height of the seat to be adjusted.

There is sometimes a requirement for the seat to be set at a different angle for example tilted rearwards instead of being horizontal. It is known to mount the seat on the pillar by a frame having flanges on which the seat rests and to which it is secured by screws, the supporting member being attached to a bracket fixed to the top of the pillar by horizontal nuts and bolts just in front and behind the pillar. By providing in the frame or bracket a vertical slot or oversize hole for the shank of one of these bolts the seat can be tilted about the other bolt as a pivot and then secured at the required angle by tightening the nuts and bolts. This has proved satisfactory as an initial factory setting but is not suitable as a user's adjustment.Because of the close spacing of the front and rear bolts the nuts and bolts must be done up very tightly by the use of a spanner if the adjusted angle is to be retained.

The present invention aims to provide a mounting of the seat on the pillar which enables the angle of the seat to be adjusted by the user at will.

The present invention consists in a mounting for a seat on a pedestal pillar of a swivelling office chair comprising a carrier extensive along the front-to-rear axis of the seat and having locating means to provide a rigid connection between the carrier and the upper end of the pillar; a supporting frame which is adapted to be secured to the seat, is pivoted to a forward portion of the carrier and has depending portions embracing and in slidable contact with opposite sides of a rear portion of the carrier; and manually operable clamping means including a pin extending through holes in one and slots in the other of the rear carrier portion and the supporting frame and capable on tightening to clamp the carrier and supporting frame firmly together in any adjusted position around the pivot within the limits allowed by the pin and slot connection.

The points at which the supporting frame is pivoted to the carrier and clamped to it by the clamping means are preferably spaced well apart so that the seat is firmly held level or at the required angle of tilt without the need for excessive tightening of the clamping means. For example the pivot may be just in front of the locating means but the clamping means be much further away from the locating means towards the part of the supporting frame to be secured to the rear of the seat.

For lateral stability the supporting frame preferably has portions enabling the seat to be attached to it at points well spaced from the central front-to-rear axis of the seat. For example the supporting frame may be Y-shaped in plan with the locating means for the pillar in the stem of the Y near the junction of its arms. Holes may be provided at the tips of the arms for screws to secure the arms to the underside of the seat.

The stem of the Y may be of inverted channel shape secured to the underside of the rear of the seat by the base of the channel and arranged with its flanges embracing the carrier. The slots for the pin and slot connection of the carrier to the supporting frame are preferably formed in the flanges and may be slightly arcuate, centred on the axis of the pivot or straight and tangential to such an arc. Plain holes for the pin are formed in the carrier.

The supporting frame may be extended rearwards behind the carrier to support a pillar carrying a back-rest. The arm may be mounted on the supporting frame by any suitable known means for adjusting the angle and/or height of the back-rest. Any convenient type of back-rest mounting may be used. The adjustment, if provided, of the back-rest is with respect to the supporting frame so that the angle between the backrest and the seat is undisturbed when the seat tilt angle is adjusted.

An embodiment of the invention is illustrated by way of example only, with reference to the accompanying drawings in which: Figure 1 is an underside plan of a mounting according to the invention fitted to the seat of a swivelling office chair; Figure 2 is a sectional elevation on line 2-2 of Figure 1.

The mounting shown in the drawings comprises a supporting frame 3, carrier 4 and screw-threaded clamping means 5.

The supporting frame 3 is Y-shaped in plan. A stem 6 of the Y is of inverted channel section with a web 7 and flanges 8. The stem is welded to or formed in one piece with angle-section arms 9 of the Y which are provided with flanges 10 co-planar with the web 7 of the stem. Webs 11 of the arms 9 taper towards the tips of the arms 9. The carrier 4 comprises a box member 12 having co-axial holes 13 in its upper and lower surfaces to receive the upper end of a pillar 14 of a floor pedestal of the chair so providing locating means for the pillar. The box member 12 may be modified to suit the form of the upper end of the particular pillar to which the seat mounting is to be secured or it may be replaced by some other type of attachment member.The particular nature of the locating means in the box member 12 or equivalent attachment member is immaterial to the present invention provided that it affords a rigid connection between the supporting frame 3 and the pillar 14.

Slots 15 are pierced through the flanges 10 near the tips of the arms. The major axes of the two slots 15 are aligned and lie at right angles to the stem 6 of the Y-shaped supporting frame. Screws 16 passed through the slots 15 engage screw-threads formed or captive in a seat 18. The front edge of the seat if straight will be arranged parallel to the common axis of the slots 15.

Side members 17 of the box member 12 extend rearwards parallel to one another.

The carrier 4 is received between the flanges 8 and pivotally connected thereto by a bolt 19 which passes through holes in the flanges 8 close to the junction with the arms and further holes in the box member 12 just in front of the locating means for the pillar.

The bolt is fitted on the far side with a nut 20. The flanges 8 embrace and are in slidable contact with the outer faces of the side members 17 which, towards the rear ends, are provided with holes 23. Slots 22 are pierced through the flanges 8. The slots 22 are either arcuate and centred on the axis of the pivot bolt 19 or straight and tangential to a circle so centred. Through the slots 22 and the holes 23 a long flat-headed bolt 24 is passed. The bolt 24 has a square below its head which engages the slots 22 in one flange 8 and prevents the bolt 24 from turning. A spacing tube 25 fits around the shank of the bolt between the two side members 17. A hand wheel 26 having a long, tubular, internally screw-threaded hub 27 is screwed onto the screw-threaded end of the bolt 24 projecting through the slot 22 of the other flange 8.The shank of the bolt 24 forms the pin, and the slots 22 the slot, of a pin and slot connection allowing the seat to be tilted about the axis of the bolt 19. When the hand wheel 26 is rotated on the thread of the bolt to tighten the clamping means formed by the bolt and hand wheel, the side members 17 are clamped tightly between the flanges 8 and the spacing tube 25 so that the carrier 4 and the supporting frame 3 are clamped in any adjusted position between those indicated by dot-dash lines in Figure 2.

At the free end of the stem 6 the flanges 8 are extended beyond the rear edge of the seat to form parallel lugs 28 between which is fitted a carrier (not shown) for a back-rest supporting arm (not shown).

WHAT WE CLAIM IS: 1. A mounting for a seat on a pedestal pillar of a swivelling office chair comprising a carrier extensive along the front-to-rear axis of the seat and having locating means to provide a rigid connection between the carrier and the upper end of the pillar; a supporting frame which is adapted to be secured to the seat, is pivoted to a forward portion of the carrier and has depending portions embracing and in slidable contact with opposite sides of a rear portion of the carrier; and manually operable clamping means including a pin extending through oles in one and slots in the other of the rear carrier portion and the supporting frame and capable on tightening to clamp the carrier and supporting frame firmly together in any adjusted position around the pivot within the limits allowed by the pin and slot connection.

2. A mounting according to Claim 1 wherein the supporting frame is pivoted to the forward portion of the carrier just in front of the locating means for the pedestal pillar, and the clamping means is much further away from the locating means towards the part of the supporting frame to be secured to the rear of the seat.

3. A mounting frame according to Claim 1 or Claim 2 wherein the supporting frame has portions enabling the seat to be attached to it at points well spaced from the central front-to-rear axis of the seat.

4. A mounting frame according to Claim 3 wherein the supporting frame is Y-shaped in plan with the forward portion of the carrier disposed in the stem of the Y

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. back-rest is with respect to the supporting frame so that the angle between the backrest and the seat is undisturbed when the seat tilt angle is adjusted. An embodiment of the invention is illustrated by way of example only, with reference to the accompanying drawings in which: Figure 1 is an underside plan of a mounting according to the invention fitted to the seat of a swivelling office chair; Figure 2 is a sectional elevation on line 2-2 of Figure 1. The mounting shown in the drawings comprises a supporting frame 3, carrier 4 and screw-threaded clamping means 5. The supporting frame 3 is Y-shaped in plan. A stem 6 of the Y is of inverted channel section with a web 7 and flanges 8. The stem is welded to or formed in one piece with angle-section arms 9 of the Y which are provided with flanges 10 co-planar with the web 7 of the stem. Webs 11 of the arms 9 taper towards the tips of the arms 9. The carrier 4 comprises a box member 12 having co-axial holes 13 in its upper and lower surfaces to receive the upper end of a pillar 14 of a floor pedestal of the chair so providing locating means for the pillar. The box member 12 may be modified to suit the form of the upper end of the particular pillar to which the seat mounting is to be secured or it may be replaced by some other type of attachment member.The particular nature of the locating means in the box member 12 or equivalent attachment member is immaterial to the present invention provided that it affords a rigid connection between the supporting frame 3 and the pillar 14. Slots 15 are pierced through the flanges 10 near the tips of the arms. The major axes of the two slots 15 are aligned and lie at right angles to the stem 6 of the Y-shaped supporting frame. Screws 16 passed through the slots 15 engage screw-threads formed or captive in a seat 18. The front edge of the seat if straight will be arranged parallel to the common axis of the slots 15. Side members 17 of the box member 12 extend rearwards parallel to one another. The carrier 4 is received between the flanges 8 and pivotally connected thereto by a bolt 19 which passes through holes in the flanges 8 close to the junction with the arms and further holes in the box member 12 just in front of the locating means for the pillar. The bolt is fitted on the far side with a nut 20. The flanges 8 embrace and are in slidable contact with the outer faces of the side members 17 which, towards the rear ends, are provided with holes 23. Slots 22 are pierced through the flanges 8. The slots 22 are either arcuate and centred on the axis of the pivot bolt 19 or straight and tangential to a circle so centred. Through the slots 22 and the holes 23 a long flat-headed bolt 24 is passed. The bolt 24 has a square below its head which engages the slots 22 in one flange 8 and prevents the bolt 24 from turning. A spacing tube 25 fits around the shank of the bolt between the two side members 17. A hand wheel 26 having a long, tubular, internally screw-threaded hub 27 is screwed onto the screw-threaded end of the bolt 24 projecting through the slot 22 of the other flange 8.The shank of the bolt 24 forms the pin, and the slots 22 the slot, of a pin and slot connection allowing the seat to be tilted about the axis of the bolt 19. When the hand wheel 26 is rotated on the thread of the bolt to tighten the clamping means formed by the bolt and hand wheel, the side members 17 are clamped tightly between the flanges 8 and the spacing tube 25 so that the carrier 4 and the supporting frame 3 are clamped in any adjusted position between those indicated by dot-dash lines in Figure 2. At the free end of the stem 6 the flanges 8 are extended beyond the rear edge of the seat to form parallel lugs 28 between which is fitted a carrier (not shown) for a back-rest supporting arm (not shown). WHAT WE CLAIM IS:

1. A mounting for a seat on a pedestal pillar of a swivelling office chair comprising a carrier extensive along the front-to-rear axis of the seat and having locating means to provide a rigid connection between the carrier and the upper end of the pillar; a supporting frame which is adapted to be secured to the seat, is pivoted to a forward portion of the carrier and has depending portions embracing and in slidable contact with opposite sides of a rear portion of the carrier; and manually operable clamping means including a pin extending through oles in one and slots in the other of the rear carrier portion and the supporting frame and capable on tightening to clamp the carrier and supporting frame firmly together in any adjusted position around the pivot within the limits allowed by the pin and slot connection.

near the junction of the arms of the Y.

5. A mounting according to any preceding Claim wherein the portion of the supporting frame extending between the pivot and the clamping means is of inverted channel section adapted to be secured to the underside of the rear of the seat by the base of the channel and arranged with its flanges embracing the carrier.

6. A mounting according to any preceding Claim wherein the carrier comprises a box member including the locating means and members extending rearwardly from the sides of the box member and forming the rear portion of the carrier.

7. A mounting according to any preceding Claim wherein the slots are formed in the depending portions of the supporting frame and are arcuate, centred on the axis of the pivot or straight and tangential to such an arc.

8. A mounting according to any preceding Claim wherein the rear portion of the carrier comprises side members between which is a spacer surrounding the pin of the clamping means, the side members, when the clamping means is tightened, being clamped between the depending portions and the spacer.

9. A mounting according to any preceding Claim wherein the clamping means comprises a screw-threaded clamping mechanism tightened by angular movement of a hand member.

10. A mounting according to Claim 9 wherein the pin of the clamping means is screw-threaded and non-rotatably mounted, and has a head on one side of the supporting frame and on the other side thereof a nut rotatable by a hand wheel.

11. A mounting according to any preceding Claim wherein the supporting frame comprises a rearward extension to support a back-rest pillar.

12. A mounting for a seat on a pedestal pillar of a swivelling office chair substantially as described herein with reference to and as illustrated by the accompanying drawings.

13. An office chair comprising a seat mounting according to any one of the pre ceding ------- Claims.~