Abstract: A hospital bed is described having a twin canting plate mechanical jack for raising the top of the bed relative to the base or chassis, for holding the top in any elevated position, and for permitting descent, in which the jack comprises a horizontally arranged main shaft which extends through the canting plates, with opposite ends of the shaft being connected to respective bell cranks of a linkage system which carries the bed top. A main shaft passes through a locking plate and a raising plate, and it is an important feature that a pedal shaft which effects displacement of the locking plate to allow the top to be lowered is also connected to the raising plate so that the raising plate locks the bed during the time that the locking plate is being moved to the release position so that subsequent descent of the bed top can be without jerk.