GB1517941A - Stepping mechanism for actuating a programming control for a machine - Google Patents

Abstract

1517941 Variable speed ratchet gearing INDUSTRIAS COPRECI SCI 21 May 1975 [21 May 1974] 21844/75 Heading F2D [Also in Division H1] In a programmed timing mechanism, which may be used in an automatic washing machine, having a pre-arranged sequence of machine operations, a ratchet stepping device includes a constantly-driven reciprocating member carrying a pawl 21 which can be engaged with ratchet teeth on a programme drum 3, Fig. 2, and which can also be lifted out of engagement, as shown in Fig. 3, thereby leaving drum 3 stationary during a secondary delay period composed of a predetermined number of cycles of the pawl reciprocation primary interval period. A snail cam 4, Fig. 3, continuously driven in a clockwise direction, imparts motion initially in direction C to a member carrying pawls 21 and 11, which subsequently returns under spring bias to the position shown in Fig. 2. An arm 10, pivoted about the fixed axis of the snail cam 4, carries an auxiliary ratchet wheel 5 provided with various recesses 12, 14, 20, 27 of differing depths which are engaged by a pawl 11 on the reciprocating member, while the ratchet wheel 5 is from time to time moved bodily closer to, or further from, drum 3 by the action of cam follower portion 9 on the arm 10, as it rides in contact with cam protrusions 8 on a cam surface 2 carried by drum 3. The resulting motion of pawl 11 determines at any time whether pawl 21 can engage with teeth of drum 3. Particular teeth 19, Fig. 6, of exceptional depth provide an additional element of time interval through a tertiary delay period which becomes terminated only when pawl 11 sinks into a recess 20 of exceptional depth on ratchet wheel 5. Reference has been directed by the Comptroller to Specification 1,484,944.