GB1065055A - Improvements relating to latches - Google Patents

Abstract

1,065,055. Latch fastenings. LOWE & FLETCHER Ltd. Nov. 25, 1963 [Nov. 24, 1962], No. 44548/62. Heading E2A. A latch comprises a housing 10 which is formed to enable it to be secured to a door, window panel or other closure member or to a surround or other fixed structure adjacent to the closure member, and a latching memiber 13 movable relative to the housing between the latching position and a releasing position in which it respectively retains and releases a complementary catch member 14 when the latter is installed on the surround of other fixed structure or on the closure member as the case may be, and an operating member 15 operatively connected with the latching member through a latching mechanism, wherein the latching mechanism comprises the combination of a toggle mechanism which has a substantially straight holding configuration and which resists counter thrust, should such be exerted on the latching member, by end loading of the toggle mechanism so that there is little or no tendency to deflect it from the holding configuration, and a deflector member 49 movable by the operating member between blocking and unlatching positions in the former of which it serves to block positively any deflection of the toggle mechanism from its holding configuration, such deflection being effected by biasing means serving also to retain the latching member in its releasing position but also positively by the deflector member should such biasing means fail to operate, the configuration of the toggle mechanism and the latching member when the latter is in its releasing position, being such that the latching member is returnable to its latching position and the toggle mechanism is returnable to its holding configuration by co-operation of the latching member and the catch member. In the construction shown the latching member 13 is bifurcated and is pivotally mounted by means of a pin 31 in the housing 10; the toggle mechanism comprises a pair of links 41 and a pivoted lever 35, the links being connected between the latching member and the pivoted lever. The biasing means 56 is a spring acting on the pivot pin 43 between the links 41 and the lever 35. The deflector member 49 is pivoted to the housing by means of a pin 53 and its free end portion is bifurcated, one limb 51 being engageable with a shoulder 37 of the lever 35 to block any deflection of the toggle mechanism from its holding configuration; the other limb 52 can engage the lever 35 when the deflector member is pivoted downwardly by means of the operating member 15 and assists if necessary in moving the latching member to its releasing position. The deflector member 49 is biased by a spring 57 to hold its limb 51 in the position in which it can engage the shoulder 37. The operating member comprises a sleeve 44 containing a cylinder-type lock mechanism; the sleeve is guided for sliding movement whilst being restrained against rotation relative the housing by the provision of guide ribs 45 formed on the housing which engage a slotted flange 46 at the inner end of the sleeve; the member 15 is biased towards its outer position by a coiled compression spring (not shown) the lock cylinder has a projection 48 which in one position can engage the deflector member to move it and in another position is ineffective to move the deflector member. The housing is in two parts and the pivot pins for the latching member 13, lever 35 and deflector member 49, are contained in recesses in one part and are held in these recesses by the other part, when the two parts are secured together by means of screws which pass through holes in flanges (not shown) of each part.