| 摘要 |
1,011,267. Adjustable back-rests. C. W. CHANCELLOR. Feb. 20, 1963 [Feb. 21, 1962], No. 6814/63. Headings A4J and A4U. An auxiliary back-rest 42 of a chair, which is located in an opening or recess 44 of a main back-rest 26, is vertically adjustable in the opening or recess 44 and is pivotally mounted about a transverse axis. The chair also includes adjustable biasing means urging the auxiliary backrest to pivot to a foremost position, and adjusting means to alter this foremost position. The lower end of a support arm 48 which carries the auxiliary back-rest 42 is mounted for vertical adjustment on a mounting plate 96 by means of a bolt 100 extending through the arm 48 and a slot in the plate 96, the arm 48 also has a pair of ribs interlocking with corresponding grooves on the plate 96. A U-shaped support 106, which is pivotally secured to rails 50, 52 attached to the seat 24, is connected to the plate 96 by rivets 108 and by a turnbuckle assembly 112. By adjusting the turnbuckle assembly 112 the angular position of the back-rest may be varied. The adjustable biasing means comprises a compression spring 138 acting between the U-shaped support 106 and an adjustable handwheel 142 in screw-threaded engagement with a rod 128 which extends through the spring 138 and is attached to a plate 134 extending between the rails 50, 52. The chair described is a vertically adjustable swivel chair which can also pivot about a transverse pivot pin 76. Two springs 94 are connected to the chair frame to resist rearward pivotal movement and by rotating a handwheel 88 the compression on the springs can be varied. |
