Improvements in or relating to electric switches for wrong-way alarm systems

摘要

845,929. Actuation of switches. RAY & CO. (LIVERPOOL) Ltd., J. W. Oct. 31, 1958 [Oct. 31, 1957], No. 33959/57. Class 38 (5). A switch, suitable to control an alarm system for indicating incorrect direction of rotation of a marine engine, comprises an engine-driven shaft 11 carrying a drum 12 which has three axially spaced flanges 12a, 12b, 12c, between which are pivotally secured two oppositely acting pawls 13, 14, controlled by springs 13a, 14a. The switch lever has two arms 16, which are pivoted on a shaft 15 and joined at their upper ends, the lower ends 16a, 16b being engageable by the pawls 13, 14, respectively. The lever carries a conducting strip 16c connecting two spring- urged spherical contacts 17, 18, which engage respectively a single contact strip 19 and two contact strips 20, 21, holes 29 serving to locate the brushes 17, 18, when the lever abuts either of the stops 27, 28. Strips 19, 20, 21 are connected to terminals in an upper portion 24 of the switch casing 10. In Fig. 1 the switch lever has been rotated by momentary engagement of the pawl 14 with the end 16b, to connect strips 19, 20, and in continued rotation of the shaft 11 the pawl 13 underrides the end 16a against the resistance of the spring 13a. Reversal of rotation of shaft 11 causes pawl 13 to momentarily engage the end 16a and so connect strips 19, 21. The lower part of the casing 10 may be oil-filled, by means of filler 30, to reduce wear on the co-operating faces of the pawls and lever ends.