Synchronizing mechanism for correlated seat/backrest motion of an office chair

• US 6,886,888 B2
• Filed: 05/17/2002
• Issued: 05/03/2005
• Est. Priority Date: 05/18/2001
• Status: Expired due to Fees

• Current Assignee: Bock 1 GmbH & Co., KG
• Original Assignee: Bock 1 GmbH & Co., KG
• Inventors: Bock, Hermann
• Primary Examiner(s): Nelson, Jr., Milton
• Application Number:
  US10/147,033
• Publication Number:
  US 20020171276A1
• Time in Patent Office: 1,082 Days
• Field of Search: 297/300.1, 297/300.2, 297/300.4, 297/300.5, 297/340
• US Class Current: 297/300.2
• CPC Class Codes: A47C 1/03205 having adjustable and lockable inclination
• CPC Class Codes: A47C 1/03255 with a central column, e.g. rocking office chairs
• CPC Class Codes: A47C 1/03272 with coil springs
• CPC Class Codes: A47C 1/03274 of torsion type
• CPC Class Codes: A47C 1/03294 slidingly movable in the base frame, e.g. by rollers

Abstract

A synchronizing mechanism for correlated seat/backrest motion of an office chair is provided with a base carrier to be placed on a chair column; a seat carrier, which is pivotable about a transverse axis and, at its front end, articulated to the base carrier; and a backrest carrier, which is also pivotable about a transverse axis and articulated to the base carrier. It is coupled with the seat carrier such that a backward pivoting motion of the backrest induces a lowering motion of the rear end of the seat carrier. The joint between the base carrier and the seat carrier is a turning and sliding joint so that the lowering motion of the seat carrier is combined with a horizontal sliding motion.

Claims

1. A synchronizing mechanism for correlated seat/backrest motion of an office chair, comprising

a base carrier (2) to be placed on a chair column (4);

a seat carrier (6), which is pivotable about a transverse axis, and at its front end (21), articulated to the base carrier (2);

a backrest carrier (7), which is also pivotable about a transverse axis and articulated to the base carrier (2) and which is coupled with the seat carrier such that a backward pivoting motion of a backrest induces a lowering motion of a rear end of the seat carrier (6);

the backrest carrier (7) being pivotably mounted on the base carrier (2) by a cam arrangement (8, 10) that defines a four-bar chain;

the cam arrangement (8, 10) being comprised of front and rear cams (8, 10) that are articulated to the base carrier (2) and of the backrest carrier (7) itself as a coupling of the four-bar chain; and

the seat carrier (6), by its rear end (19), being articulated to the backrest carrier (7);

wherein the joint between the base carrier (2) and the seat carrier (6) is a turning and sliding joint (22) so that a lowering motion of the seat carrier (6) is combined with a horizontal sliding motion rearwards.

2. A synchronizing mechanism according to claim 1, wherein the turning and sliding joint (22) comprises, in the seat carrier (6), an oblong-hole-type connecting member (25) which extends in a longitudinal direction and in which a bearing journal (26) of the, seat carrier (6) is guided.

3. A synchronizing mechanism according to claim 1 wherein a link between the seat carrier (6) and the backrest carrier (7) is integrated into a front joint (12) between the front cam (8) and the backrest carrier (7).

4. A synchronizing mechanism according to claim 1, wherein a distance (a) of two joints (12, 13) between the backrest carrier (7) and the two cams (8, 10) is approximately equal to a length (L10) of the rear cam (10) and greater than a length (L8) of the front cam (8).

5. A synchronizing mechanism according to claim 1, wherein the cams (8, 10) are mounted externally on the seat carrier (6) with the backrest carrier (7) being attached thereto by way of bearing checks (34) that are applied externally on the cams (8, 10).

6. A synchronizing mechanism according to claim 5, wherein, in a plan view related to their joint axis, the cams (8, 10) have a widened sheet configuration so that in none of the pivoted relative positions of the four-bar chain formed thereby, there is a possibility of reach-through between the cams (8, 10), base carrier (2) and backrest carrier (7).