Chair having a clamping device for adjusting the inclination of the back and/or seat

• US 4,693,514 A
• Filed: 03/10/1986
• Issued: 09/15/1987
• Est. Priority Date: 07/10/1984
• Status: Expired due to Term

• Current Assignee: Rolf Volkle
• Original Assignee: Rolf Volkle
• Inventors: Volkle, Rolf
• Primary Examiner(s): Dorner, Kenneth J.
• Assistant Examiner(s): Binder, Mark W.
• Application Number:
  US06/857,749
• Time in Patent Office: 554 Days
• Field of Search: 297/374, 297/316, 297/320, 297/311, 297/312, 297/322, 297/375, 297/354, 297/355
• US Class Current: 297/374
• CPC Class Codes: A47C 1/022 having independently-adjustable supporting parts
• CPC Class Codes: A47C 1/027 by means of clamps or friction locking members

Abstract

It is possible to lock the inclination of the back of a seat by the locking device by means of a strip friction connection. The locking device is arranged as a modular unit with an axial motion by means of friction connection disk (13a) in bearings (10a) of the seating. A self-locking eccentric (17) bearing by its pivoting axis (16) on the tension rod (14) and with an extremely small rise of its eccentric curve is frontally engaged with the assembly of friction connection disks (13). Thus, part of the handling resistance of the eccentric is considerably reduced due to the small rise of its eccentric curve and on the other hand, due to a shortening, characteristic of the system, of the pivoting travel of the eccentric (17), said travel being still sufficiently short.

Claims

1. Chair, particularly a roatable office chair, having a foot rest which includes a central supporting spindle, seat means (10, 23) carried by the support spindle and having vertical ribs (10c;

10c'"'"';

10c") formed to define support bearings (10a;

10a'"'"') which are located at least approximately symmetrically to the plane of symmetry of the chair, a back rest carried by the seat means, and a clamping device supported in the bearings and connected to at least one of the seat means and back rest for adjusting the inclination of at least one of the seat means and back rest by laminar friction,

said clamping device being composed of;

a packet (12,12'"'"') of laminae (12a;

12a'"'"') which are provided with elongated holes and are articulated to at least one of the seat means and back rest;

a friction lock disc packet (13;

13'"'"') of annular, coaxial friction lock discs (13a;

13b;

13a'"'"';

13b'"'"') having friction locking faces which lie against the laminae (12a;

12a'"'"');

a clamping bolt (14;

14'"'"') which passes through the laminae and discs; and

a manually actuable lever operatively associated with the clamping bolt for effecting relative displacement between the clamp bolt and the laminae and discs in order to control the clamping of the laminae between the discs;

characterized in that;

said friction lock discs are movably mounted in said support bearings, so that said clamping device is movable in the direction of the axis of said clamping bolt;

the plane of symmetry of the chair passes throgh said packet of laminae and said friction lock disc packet; and

said lever constitutes a self-inhibiting eccentric having a pivot axis fixed to said clamping bolt and bears against one end of said friction lock disc packet such that pivotal movement of said lever about its pivot axis causes axial displacement of said clamping bolt and causes the parts of said packet of laminae and friction lock disc packet which are respectively opposite sides of the plane of symmetry of the chair to move in respectively opposite directions.

2. Chair according to claim 1, characterized in that the friction lock disc packet (13;

13'"'"') is disposed approximately symmetrically to the vertical plane of symmetry (a--a) of the chair.

4. Chair according to claim 1, characterized in that the eccentric (17;

17'"'"') includes two eccentric discs (17a;

17a'"'"') whose eccentric curves engage at the frontal face of the adjacent friction lock disc (13;

13a'"'"') and through which penetrate the free ends of the pivot axis (16;

16'"'"').

5. Chair according to claim 1, characterized in that the support bearings (10a;

10a'"'"') disposed on either side of the plane of symmetry (a--a) are each penetrated by a single friction lock disc (13a;

13a'"'"').

6. Chair according to claim 1, characterized in that all support bearings (10a;

10a'"'"') are components of a single cast piece.

7. Chair according to claim 6, characterized in that the cast member is an injection molded plastic member which supports a seat shell (not shown) that has the same basic outline as the seat (FIGS. 1-3, 3a).

8. Chair according to claim 7, characterized in that the support bearings (10a) are formed by sleeves which are shaped to vertical ribs of the injection moded plastic member.

9. Chair according to claim 7, characterized in that said chair further comprises a hinge having an axis and connecting said seat back to said seat means and the laminae (12a) of the clamping device, which serves exclusively for adjusting the inclination of the seat back are penetrated, at one end, by the hinge axis (18).

10. Chair according to claim 6, characterized in that said seat means comprise a seat support rigidly held by the support spindle and an adjustable-inclination support frame pivotally supported by said seat support, and said cast piece is produced by metal ejection molding, is made of aluminum, and forms said adjustableinclination support frame.

11. Chair according to claim 10, characterized in that the support bearings (10a'"'"') are formed by bores in four vertical ribs of the cast member which are arranged symmetrically to the plane of symmetry (a--a) and each pair of bores on each side of the plane of symmetry (a--a) is penetrated by a single friction lock disc (13a'"'"').

12. Chair according to claim 10, characterized in that said chair further comprises a hinge having an axis and connecting said seat back to said support frame, said laminae (12a'"'"') are articulated, on the one hand, to the seat support (23) and, on the other hand, to the hinge axis (18'"'"') of the back rest in such a manner that, if the inclination is changed by means of the clamping device, a displacement ratio between the seat support (23) and back rest of about one to two results.

3. Chair according to claim 13, characterized in that said lever includes a cylindrical bearing bolt which is perpendicular to the clamping bolt (14;

14'"'"'), defines the pivot axis of said lever and has an internaly threaded bore in which said clamping bolt is fixed.