GB514110A - Improvements in combined electric fuses and switches - Google Patents

Abstract

514,110. Snap-action switches. BROOKHIRST SWITCHGEAR, Ltd., and LANCELEY. C. April 27, 1938, No. 12540. [Class 38 (v)] A switch fuse suitable for mounting on the frames of machine tools comprises a frame plate 10 formed with an aperture 10a through which is inserted the movable contact-carrying block 12 mounted on an operating spindle 24 carried by a closure plate 11 screwed to the frame plate 10. Fixed contacts 14 are arranged in opposite pairs on the side limits of a frame member 17 and are adapted to be bridged by contacts 30 pivoted on the block 12 and connected in pairs by fuses 34 arranged in recesses and enclosed by a cover 38. A snap-action is provided by a spring toggle link 48 connected between a lug 47 on a plate 46 fixed on spindle 24, and a fixed lug 52 projecting from the closure plate 11. In the on position of the switch, Figs. 2 and 4, a part 62 of plate 46 engages behind the frame plate 10 and prevents withdrawal of the switch block 12. In the off position, plate 46 is turned through a rightangle and the block 12 may be withdrawn. In this position lugs 56, 57 engage recesses 58, 59 in aperture 10a and prevent rotation of the switch during withdrawal or replacement, the switch block 12 also having a suitable crosssection so as to assure this. When the switch is withdrawn for replacement of the fuses, a pair of spring-urged folding doors 63, Fig. 2, close the aperture 10a. These are opened by inserting the block 12 and are held wide open by the engagement of the rounded end of the lug 52 with door-operating links 72. A modification is also described for use as a change-over switch in which there are provided two sets of fixed contacts carried on two frames 17.