Rotary knob manual control mechanism - uses surrounding wire locking spring resting on lower flange of knob and looping under lug of plate to restrict knob rotation

摘要

The manual control device comprises a knob (3) rotatably mounted on an upstanding rod (2) of a base plate (1). The latter has, on diametrically apposed sides of the knob, a projection (10) and a recess (11). To provide resistance to accidental turning of the knob a wire spring (4) is provided, the spring being bent into an eight sided polygonal shape with its two ends (7,8) being adjacent one another and bent into hook shapes. Once the knob is in place a U-shaped portion (S) of the spring is hooked under the plate projection (10), the main portion of the spring forced around the knob, to rest on a lower flange of the knob, and the spring end, hooked under the plate recess edges. Fluting or the like on the knob side assists the spring grip.