ADJUSTABLE BED WITH MECHANICAL JACK

摘要

An adjustable bed (10) includes a base frame (12), a mattress frame, and linkage for mounting the mattress frame for rela- tive movement with respect to the base frame (12). A mechanical jack (68) is operatively connected to the base frame (12) and the linkage for moving the mattress frame between high and low positions. The mechanical jack (68) includes a housing (72). A bear- ing (86) supports a ram (70) within the housing (72) for extension and retraction. A drive plate (90) and a hold plate (92) define apertures (146) through which the ram (70) extends. A drive bar (114) is shifted by rotation of an actuator shaft (82) to lock the drive plate (90) to the ram (70) and extend the ram (70) from the housing (72). A drive spring (102) resiliently biases the drive plate (90) to un unlocked or return position. A hold spring (106) biases the hold plate (92) to prevent return movement of the ram (70) into the housing (72). A release bar (112) is shifted into engagement with the hold plate (92) upon reverse rotation of the actu- ator shaft (82) to release the hold plate (92) and permit lowering of the ra m (70) into the housing (72).