GB1495936A - Tumbler dryers - Google Patents

Abstract

1495936 Tumbler dryers T I DOMESTIC APPLIANCES Ltd 13 Dec 1974 [21 Dec 1973] 59654/73 Heading F4G A tumbler dryer comprises a drying drum 1, an electric motor of the induction type for rotating the drum 1 about its longitudinal axis during a drying operation, electrical switching means for effecting reversal of the direction of rotation of the motor, and means responsive to rotation of a rotatable part of the dryer driven by the motor for actuating the switching means at predetermined intervals to cause the latter means to reverse the direction of rotation of the motor and hence the drum. As shown the responsive means comprises a screw threaded member 4 rotatable with the drum 1 and having mounted thereon a nut 6. The nut 6 is prevented from being rotated by a face of a lever 8 and works between two flages 12, 13 of the lever such that an extension 11 thereof operates a micro-switch 9 such that in one condition of the switch the motor rotates in one direction and in another condition the motor rotates in the opposite direction. Alternatively a member rotated indirectly by the drum may actuate a linearly slidable member which operates the microswitch (Fig. 2, not shown). In another embodiment a cam rotated by a pawl and ratchet arrangement works on a lever such that the latter operates the microswitch (Fig. 3, not shown). A shaft of the cam may have a worm which in use drives a pinion coupled to a timing mechanism controlling the drying cycle of the dryer. Various circuits, suitable for starting and reversing the motor are disclosed (Figs. 4 to 6, not shown). The invention is described with reference to the dryer of Specification 1,226,951.