KEYBOARD SUPPORT WITH AUTOMATIC LOWERING MECHANISM

摘要

KEYBROAD SUPPORT WITH AUTOMATIC LOWERING MECHANISM An adjustable auxiliary work support assembly which includes a shelflike auxiliary support connected to one end of a parallelogram linkage. The other end of the linkage is connected to a carriage which is slidably supported within a guide rail fixed to the underside of a main support. The linkage enables the auxiliary support to be vertically swung upwardly and downwardly. A cam structure includes first and second cams respectively fixed to the rail and linkage, and a cam follower pivotally mounted on the carriage and cooperating between the cams to effect automatic lowering of the auxiliary support when the latter is closely adjacent the front edge of the main support and is pushed inwardly toward the latter. The cam structure also includes a pair of side cams fixed to the carriage in strattling relationship to the cam follower, and which cooperate with the fixed cam on the linkage to effect automatic lowering of the linkage when it is pivotally swung sidewardly beyond a permissible angular extent.