Electro:mechanical programme timer - uses synchronous cam drive to increment programme disc with facility for inhibition during weekends

摘要

An electro-mechanical programmed timer uses a drive unit to operate a cam to increment the programme disc with high accuracy. The programme disc is located on a ratchet wheel with teeth cut on the periphery. A synchronous drive unit rotates a cam (8) with a selector dial (3) to give increments in the range 1-15 minutes. The cam operates against a pivotted lever to increment the disc through a ratchet pawl. A spring strip holds the lever in a steady motion. A pivotted contact lever (19) is moved by the programme disc segments to operate a relay with an actuating lever that locates against a stop (22). A programme disc (18) provides an incremental motion on a day-by-day basis, with a facility to inhibit operation during the weekend.