1. In a control mechanism, a control device, cam means arranged to operate said control device, an operator, means for supporting said operator and providing a limited range of movement therefore, said operator being arranged to operate said control device conjointly with the cam means, said cam means having two separate camming portions at different levels for operating the control device, the camming portion at one level being within the range of movement of the operator providing conjoint operation of the control device and the camming portion at the other level being beyond the range of movement of the operator to exclude operation of the control device by the operator.

2. In an automatic control mechanism, a control device movable from a first position to a second position, power operated means for driving the control device from said first position to the second position, biasing means biasing said control device toward said first position, latching means for holding said control device in the second position against the bias provided by the biasing means, said latching means including a first latching element and a second latching element arranged to selectively engage and disengage, the first element being relatively stationary and arranged to hold the second element stationary when the elements are engaged, and motion transmitting means between the control device and said second element, said motion transmitting means being arranged to provide a mechanical advantage for the second element in resisting the biasing means, thereby reDucing the force required by the first element in holding the second element in resisting the biasing means, thus reducing the force necessary to release the latching elements for allowing the control device to return to its first position.