GB642005A - Ratchet mechanism - Google Patents

Abstract

642,005. Ratchet gearing. GUARDIAN ELECTRIC MANUFACTURING CO. Feb. 19, 1948, No. 4905. Convention date, July 22, 1940. [Class 80(iii)] [Also in Group XXXIX] An electrically-actuated ratchet mechanism, particularly applicable to the selective operation of a contact arm 64 of a rotary switch to complete a circuit from a common contact 71 to one of a series of contacts 62 of different electrical circuits, comprises a ratchet wheel 17 secured to the spindle 15 of the rotary switch and a pawl 36 secured to the armature 31 of an electromagnetic device A and extending in the direction of the axis of the ratchet wheel across the periphery of the wheel. The armature 31 pivots about an axis transverse to that of the wheel 'to actuate the pawl 36 against a spring 40, the pawl being allowed a certain amount of lateral movement through its connection by pins 35 and 31b to the armature for accommodating itself to the curvature of the ratchet wheel. The movement of the pawl is limited by its passing through an opening 41 which is adjustable by plates 42, 43. A check pawl 45 adapted to be operated by the armature 48 of a second electromagnet B is provided to prevent reverse movement of the ratchet wheel during the periods when pawl 36 is not driving. This device may be actuated when desired to release the ratchet wheel to allow, it to return under the influence of a spring 18 to an initial position determined by a pin 22 thereon engaging a stop 23. In a modified arrangement a double pawl arrangement each with an actuating electromagnet is provided to allow step-bystep operation in either direction of the ratchet wheel, a spring-loaded check pawl being provided to prevent undesired movements.