GB1400554A - Programme control units - Google Patents

Abstract

1400554 Time switches EATON CORP 15 May 1972 [18 May 1971] 22613/72 Heading H1N [Also in Division H2] A programme control unit, suitable for example, for a washing machine, comprises a main rotary programme switch unit 47, a subsidiary rotary programme switch unit 1, rotatable about a common axis 28, a timing device 36 arranged to drive the main unit 47 mechanically in a step-wise motion, means for coupling the subsidiary unit 1 to the timing device 36 in one or more discrete relative angular positions such that they rotate together, and disabling means dependent on the angular position of the main unit 47 for mechanically disabling the coupling means. As shown a motor 46 drives a disc 36 by means of its peripheral teeth 3, and a cam 4 thereon oscillates a lever 22 against spring 20 to cause a pawl 23 to step a main programme cam 47 by teeth 19 thereon. A coaxial subsidiary programme cam 1 carries a pawl 9 urged by a spring 13 such that a projection 35 engages a recess 40 in disc 36 as the latter rotates, thereby entraining cam 1 with disc 34, unless a blocking lever 15 is moved by spring 38 to lift the pawl 9 and prevent coupling. Lever 15 is controlled by a sensing arm 17 thereon following a track 18 on cam 47. Thus the drive to cam 1 is coupled and uncoupled only when cam 1 itself is in a predetermined position (i.e. pawl 9 opposite lever 15) and also the main cam 47 is in a predetermined position (dependent upon shape of track 18). This may be used, for example, to ensure that a washing machine motor reversal by contacts operated by recesses 2 cannot occur during a high speed spin programme set by cam 47. A number of pawls 9 and more than one recess 40 may be provided, thus providing coupling at several discrete relative angular positions, but the pawls and recesses must be so angularly staggered that only one pawl can engage at a time thus permitting uncoupling by lever 15 at a single position. Circuits are disclosed (Figs. 3 and 4, not shown) for ensuring that spin can start only when the reversal contacts are set for a given direction of rotation (See Division H2).