GB629051A - Improvements in electric tumbler switches - Google Patents

Abstract

629,051. Tumbler switches. SIMPLEX ELECTRIC CO., Ltd., and HUNT, J. J. H. Oct. 22, 1947, No. 28199. [Class 38(v)] A switch comprises an operating lever 22 rotatable on a spindle 21 and,having face cams 25 formed on the side of its hub 24 such that as the lever 22 is moved, the cams 25 engage ribs 31 of a block 30 to move it axially along the spindle 21, the block 30 having a flat portion engaging the base 10 to prevent its rotation. Loosely mounted on a cylindrical portion 33 of the block is a bridging contact 34 which in the " on " position of the lever is pressed by a pair of springs 36 against a fixed contact pair 15. To ensure that one end 37 of the contact 34 leaves its fixed contact before the other, the springs 36 may have different strengths or, as shown, the block 30 may engage the contact 34 off-centre. In the opening movement, the end 37 of the contact 34 is arrested by an abutment 42 after moving through a small distance sufficient to prevent re-striking of the arc, after which the contact 34 pivots about the abutment 42 whereby its other end moves through a greater distance for isolation. In the embodiment described, the switch mechanism is duplicated on either side of the lever 22 and controls a pair of contacts 34. Should the springs 36 acting on one contact 34 be stronger than those acting on the other contact 34, the block 30 controlled by the weaker :springs will be :arrested by a washer 38 and then the other block will be moved, the lever 22 being slidable on the spindle 21 to permit this. The switch operation may be assisted by a nose 28 on the lever 22 engaging a spring- pressed member 29 in the base. The lever 22 passes through an indicator plate 40 slidable between the cover 13 and a platform 41 carried by the body 10 whereby " on " and " off " legends are brought opposite an aperture in the. cover.