Working chair with synchronous seat and back adjustment

• US 6,431,649 B1
• Filed: 06/28/1996
• Issued: 08/13/2002
• Est. Priority Date: 11/01/1993
• Status: Expired due to Fees

• Current Assignee: Labofa A/S (Holmris Holding A/S)
• Original Assignee: Labofa A/S (Holmris Holding A/S)
• Inventors: Hensel, Willi B.
• Primary Examiner(s): Cuomo, Peter M.
• Assistant Examiner(s): VU, STEPHEN A
• Application Number:
  US08/591,599
• Time in Patent Office: 2,237 Days
• Field of Search: 297/300.2, 297/316, 297/354.1, 297/300.1, 297/285
• US Class Current: 297/300.2
• CPC Class Codes: A47C 1/03255 with a central column, e.g. rocking office chairs
• CPC Class Codes: A47C 1/03294 slidingly movable in the base frame, e.g. by rollers

Abstract

In a working chair with a seat (12), a back (14) and a lower frame the seat (12) is pivotally connected in the proximity of the front edge with a carrier frame (11) whereas a back support (15) connected with the back (14) is pivotally connected with the carrier frame (11) as well as with the seat (12). The pivot connections are provided for synchronous movement of the seat (12) and the back (14), whereby the seat from a backwards inclining extreme position may be moved to a forwards inclining extreme position and the back (14) synchronously therewith from a backwards inclining position in which it forms a maximum angle with the seat towards a more erect position, while gradually reducing its angle with the seat. The pivot connection (13) between the seat (12) and the carrier frame (11) is formed to allow a perpendicular, substantially translatory movement of the seat (12) so that the front edge of the seat (12) in said forwards and backwards inclining extreme positions is displaced forwards and upwards, backwards and downwards, respectively, in relation to the carrier frame (1, 11).

Claims

1. A working chair with a seat (2, 12), a back (4, 14) and a lower frame, the frame comprises, a vertical adjustable supporting pillar and a carrier Frame (1,11) connected with an upper end of said pillar, the seat (2,12) being pivotally connected with said carrier frame in proximity of its front edge by a first pivot connection(3,13) with a horizontal axis of rotation,said first pivot connection (3, 13) comprising a pivot pin (3a, 13a) connected with the seat (2, 12) and the carrier frame (1, 11), one of said seat and said carrier frame being provided with a track (3b, 13b) inclined with respect to a horizontal direction for allowing a substantially translatory movement of the seat (2, 12) perpendicular to the axis of rotation with respect to said carrier frame, whereas a mounting arm (7, 17) in firm connection with a back support(5, 15) connected with the back (4, 14) is pivotally connected with the carrier frame (1, 11) as well as with the seat (2, 12) by second and third pivot connections (8,9;

19,21) having axes of rotation mutually parallel and parallel with the axis of said first pivot connection (3, 13), said pivot connections being designed for synchronous movement of the seat (2, 12) and the back (4, 14), whereby the seat (2, 12) from a backwards declining rest position by rotation in said first pivot connection (3, 13) may be moved to a working position and the back (4, 14) synchronously therewith may be moved from a backwards declining extreme position in which it forms a maximum angle with the seat towards a more upright position while gradually reducing its angle with the seat, wherein the track (3b, 13b) is directed obliquely upwardly towards the front edge of the seat (2, 12) and is inclined at an angle of 40°

to 70°

with the vertical axis of the supporting pillar to provide a range of said translatory movement by which the seat (2, 12) is movable from said backwards declining rest position in which the front edge of the seat (2, 12) is displaced backwards and downwardly with respect to the carrier frame (1, 11) to a forward declining extreme position, in which the front edge of the seat (2, 12)is displaced forwardly and upwardly with respect to the carrier frame (1, 11).

2. The working chair as claimed in claim 1 characterized in that said track (3b, 13b) is provided by a member connected with the seat.

3. The working chair according to claim 1, characterized in that the back support comprises two substantially rectilinear parts (15, 16) forming an obtuse angle (V) with each other and of which one (15) is substantially vertical and connected with. the back (14), whereas the other is mounted in a back support holder (23) positioned under the seat (12) and connected with the carrier frame (11) in such a manner that by means of an arrestable operating member (25), it may be displaced in its longitudinal direction and be maintained in various adjustments in said back support holder (23) for simultaneous adjustment of the seat depth and the height adjustment of the back in relation to the sea (12).

4. The working chair according to claim 3, characterized in that said second part (16) of the back support includes an elongated rack member (24), and that the operating member includes a toothed wheel (25) engaging a tooth of the rack member (24), wherein a releasable clutch (26) is connected with a pivot handle (29).

5. The working chair according to claim 4, characterized in that a transmission (30) is provided between the toothed wheel (25) and the pivot handle (29), said transmission being provided so that said second part (16) of the back support is displaced backwards and upwardly in relation to the seat by rotation of the pivot handle (29).

6. The working chair according to claim 1, characterized in that the back support (15) is connected with the carrier frame through two mounting arms (17,18), wherein one (17) of the arms includes two mutually pivotally connected arm portions (17a, 17b), one of which is pivotally connected with the carrier frame (11) while the other is in firm connection with the back support (15), whereas the pivotal connection (21) between the two arm portions (17a, 17b) forms part of said pivot connection with the seat (12), the second mounting arm (18) being pivotally connected with the carrier frame (11) and with the portion (17b) of the first arm (17) connected with the back support (15).

7. The working chair according to claim 6, characterized that in each of said backwards declining and forward declining extreme positions, the seat (12) forms an angle of about 10°

with the horizontal direction in both of said extreme positions, the angle of the back (14) with the seat (12) is larger than in a neutral position between said extreme positions.

8. The working chair according to claim 7, characterized in that the angle of the back (14) with the seat (12) in the backwards declining extreme position of the seat is about 7°

larger and in the forward declining extreme position of the seat is about 3°

larger than in said neutral position.

9. The working chair according to claim 2, characterized in that the back support (15) is connected with the carrier frame through two mounting arms (17,18), wherein one (17) of the arms includes two mutually pivotally connected arm portions (17a, 17b), one of which is pivotally connected with the carrier frame (11) while the other is in firm connection with the back support (15), whereas the pivotal connection (21) between the two arm portions (17a, 17b) forms part of said pivot connection with the seat (12), the second mounting arm (18) being pivotally connected with the carrier frame (11) and with the portion (17b) of the first arm (17) connected with the back support (15).

10. A working chair according to claim 9, characterized in that in each of said backwards declining and forward declining extreme positions the seat (12) forms an angle of about 10°

with the horizontal direction and that in both of said extreme positions, the angle of the back (14) with the seat (12) is larger than in a neutral position between said positions.

11. A working chair according to claim 10, characterized in that the angle of the back (14) with the seat (12) in the backwards declining extreme position thereof is about 7°

larger and in the forward declining extreme position of the seat is about 3°

larger than in said neutral position, in which said angle presents its minimum value.