Abstract: An apparatus for detachably mounting an electrical assembly unit to a supporting frame comprises a rotatable threaded rod mounted on the supporting frame and extending in the direction along which the electrical unit is moved to be mounted or detached. Pressing means is mounted on the threaded rod movably in the axial direction thereof. Stop means is fixedly provided on the electrical unit in such position to be engaged by the pressing means. By rotating the threaded rod in one direction, the stop means is forcefully engaged with the pressing means, whereby the electrical unit is moved to the tightly clamped position. The rotation of the threaded rod in the other direction causes the movement of the pressing means in the opposite direction, whereby the stop and hence the electrical assembly unit are moved to the removed or detached position under the pressing force of the engaged pressing means.

Abstract: A motor timer comprises a prefabricated timing mechanism block including a drive motor, a reduction gear, a clutch and a timing gear; a prefabricated contact mechanism block including a leaf-spring contact assembly and an actuating member for actuating the leaf spring contact interconnecting; and means for assemblying the blocks at a final stage of assembly.