Chair chassis

• US 8,613,482 B2
• Filed: 02/01/2011
• Issued: 12/24/2013
• Est. Priority Date: 02/08/2010
• Status: Active Grant

• Current Assignee: Hangzhou Zhongtai Industrial Company Limited
• Original Assignee: Hangzhou Zhongtai Industrial Company Limited
• Inventors: Ni, Yong-Xing
• Primary Examiner(s): GABLER, PHILIP F
• Application Number:
  US13/018,959
• Publication Number:
  US 20110193384A1
• Time in Patent Office: 1,057 Days
• Field of Search: 297/301.3, 297/301.4, 297/301.5, 297/311, 297/301.1, 297/302.1, 297/302.3, 297/302.4, 297/302.5
• US Class Current: 297/302.3
• CPC Class Codes: A47C 1/026 by means of peg-and-notch or pawl-and-ratchet mechanism

Abstract

A chair chassis is revealed. The chair chassis includes a seat base, a middle base and an adjustment member. A sliding plate is connected to each side of the seat base. A sliding slot is arranged at a front and a rear end of each sliding plate and a pulley is arranged transversely between two sliding slots. The two pulleys connect to a tilting board. The middle base between the two sliding plates connects to the tilting board and the two sliding plates by the pulley on the front end. A third pulley slides over a slant part of the middle base. The adjustment member includes a rack, a locking piece and a lock adjustment rod for control of movement of the locking piece to be engaged with and separated from the rack. Thus users with various weights can use the same chair chassis and operate the chair chassis easier.

Claims

1. A chair chassis comprising a seat base, a first pulley, a second pulley, a tilting board, a middle base, a third pulley and an adjustment member, wherein:

the seat base is fixedly connected to a bottom of a seat of the chair and has two sliding plates connected to the left side and the right side of the seat base respectively, wherein two first sliding slots are inclined and symmetrically disposed on the front end of each of the two sliding plates, two second sliding slots are declined and symmetrically disposed on the rear end of each of the sliding plate, and two slants are symmetrically disposed on the edge of the rear end of each of the sliding plates;

the first pulley is disposed between the two first sliding slots and consists of a shaft and two wheels, wherein the two wheels are rotatably connected to each of two ends of the shaft, and each wheel is slidably located in each first sliding slot;

the second pulley is disposed between the two second sliding slots and consists of a shaft and two wheels, wherein the two wheels are rotatably connected to each of two ends of the shaft, and each wheel is slidably located in each second sliding slot;

the tilting board is fixedly connected to a chair back of the chair and is fixedly connected to the shaft of the first pulley and the shaft of the second pulley;

the middle base is fixedly connected to a leg of the chair and is set between the two sliding plates of the seat base and rotatably connected to each of two ends of the shaft of the first pulley, such that when the chair back of the chair is reclined by user, the tilting board is pressed synchronously to be reclined by rotating about the shaft which is rotatably supported by the middle base;

the middle base includes a slant part on the rear end thereof and the slant part is disposed above the slant on the rear end of each sliding plate;

the third pulley is arranged over the slant part of the middle base and includes a shaft and at least one wheel disposed on the shaft, the two ends of the shaft are fixed on the left and right sides of the seat base and the at least one wheel is movably leaning against the slant part of the middle base; and

the adjustment member includes a rack, a locking piece and a lock adjustment rod, wherein the rack is connected to the shaft of the first pulley and the shaft of the second pulley, and disposed with a torsion spring set on the shaft of the first pulley and on a left side and a right side of the rack;

a plurality of teeth are disposed on a rear end of the rack for facing the locking piece;

wherein the locking piece is used to lock or unlock with the teeth of the rack while the lock adjustment rod is connected to the locking piece for control of the forward/backward movement of the locking piece;

wherein when the chair back of the chair is reclined by a user who sits on the seat of the chair, the tilting board is synchronously pressed and reclined to rotate about the shaft of the first pulley while the middle base and the shaft of the first pulley remain still, such that the seat base will move while the two wheels of the first pulley and the two wheels of the second pulley slide relatively within the first sliding slot and the second sliding slot of the seat base respectively, and the at least one wheel of the third pulley slides over and leaned against the slant part of the middle base with the user'"'"'s weight pressed on the seat base;

wherein when the lock adjustment rod is pulled to drive the locking piece moving backward, the locking piece is separated from the teeth of the rack to be in the unlock condition, then the user enables the chair back of the chair and the tilting board to be synchronously pressed and reclined to rotate about the shaft of the first pulley, the tilting board is then pressed to drive the rack moving vertically around the shaft of the first pulley, the lock adjustment rod is then pulled to drive the locking piece moving forward, the locking piece is then locked with the teeth of the rack to be in the lock condition.

2. The device as claimed in claim 1, wherein an angle between the slant arranged at the edge of the rear end of the sliding plate and a horizontal plane is in the range of from 30 degrees to 40 degrees.

3. The device as claimed in claim 1, wherein a diameter of the wheel of the first pulley, a diameter of the wheel of the second pulley and a diameter of the wheel of the third pulley all fall into the range from 25 mm to 35 mm.

4. The device as claimed in claim 1, wherein the adjustment member further includes an elastic part, wherein one end of the elastic part is connected to the lock adjustment rod while the other end thereof is connected to the locking piece.

5. The device as claimed in claim 4, wherein the elastic part is a two-arm torsion spring and an angle between the two arms of the two-arm torsion spring is in the range of from 80 degrees to 120 degrees.

6. The device as claimed in claim 1, wherein an inner side of the slant part of the middle base is further disposed with a partition, a cover plate and a block, wherein a through hole for the locking piece moving forward/backward therein is mounted on the partition;

the cover plate is arranged above the locking piece and the block is arranged under the locking piece for receiving the locking piece;

the partition is further fixed with an elastic pad having a concave-convex surface and the lock adjustment rod leans against the concave-convex surface.