GB781579A - Improvements in and relating to interlocking mechanism - Google Patents

Abstract

781,579. Actuation of switches. ENGLISH ELECTRIC CO., Ltd. April 29, 1955 [April 30, 1954], No. 12690/54. Class 38 (5). An interlocking mechanism has two members 11, each of which may occupy a position A or a position B, but which may not simultaneously occupy positions A, the interlock comprising a plate 10 slidable between positions in which an aperture therein is adjacent one or other of the members 11, each of which has a part which may extend through the aperture when the member occupies position A, and is capable of movement to position B when the aperture is adjacent the member. There may be four members 11, pivotable about shaft 12, only one of which can occupy position A at any time. The members 11 may be so shaped (Fig. 1b) that when in position A a part thereof extends through the aperture and prevents the plate 10 from moving to expose any of the other members, all of which are thus locked in position B by the plate. The aperture may have a cutaway portion to engage and lock the protruding part of a member 11 in position A. The plate 10 may have more than one aperture separated by a distance which is not equal to the distance between members 11 and arranged so as to give access to only one member 11 at a time. In an alternative arrangement (Fig. 4) a plate 13 provided with a slot 14 and a keyhole 15 is slidable in a frame 16. Two rows of push-rods 17a, 17b are slidable in bushings 16b, and support arms 16c carry spindle 18 on which a T-shaped lever 19 is pivoted. Contacts 20 are arranged adjacent the foot of the T and the ends of the arms of the T are connected to the push-rods so that when 17a is depressed, 17b is raised. All the push rods 17b extend through slot 14, but only one rod 17a can extend through hole 15, thus only one pair of contacts 20 can be open at a time. The rods 17a may have necks 17c by which they can be locked in keyway 15a. Switchgear actuating members 30 (Fig. 6) pivotally mounted on a spindle 31 have their A and B positions determined by stops 40, 41. The member 30 shown is locked by the sliding plate 42 in position B. When all members 30 are locked, contacts 44, 45 are closed and may complete the tripping circuit of an oil circuit-breaker. The plate 42 cannot be moved unless shaft 51 is turned to disengage fixture 52 from member 63, and this shaft cannot turn unless it is pressed inwardly against a head 50 to open contacts 44, 45 and disengage pin 53 from a hole 43a in front cover 43. When shaft 51 is turned, pin 53 engages a slot in plate 42, causing the plate to slide and expose an actuating member 30 which may then be moved to position A. Specification 779,354 is referred to.