Patent GB-895482-A (GB)
Title: Improvements relating to quick-release latches
IPC: B64D25/06
Filed: 1957-07-05
Abstract: 895,482. Latch fastenings. HARLEY PATENTS (INTERNATIONAL) Ltd., and HARLEY, F. B. July 4, 1958 [July 5, 1957], No. 21396/57. Class 44. A quick release latch includes a body portion 10 for releasably securing at least two subsidiary portions each comprising a plate 11 with latching means 13 (shown as a hole) in it, the body portion having in it spaces into which the plates 11 can be inserted substantially on a common plane, a number of bolts 50 each mounted to move longitudinally in the body in a direction substantially perpendicular to the said plane, each bolt traversing one of the spaces to enter the latching means in the associated plate 11 to retain the latter, a retracting member 40 movable to retract all the bolts simultaneously, a rotary operating member (not shown) connected to turn a shaft 60 having extending through it a transverse pin 65, projecting portions of which form a cam follower co-operating with a face cam 64 so that rotation of the operating member produces relative longitudinal movement between the face cam 64 and the shaft, such longitudinal movement being arranged to move the retracting member to retract the bolts. As shown each plate 11 has a narrow portion 12 through which extends the hole 13 by which the plate is secured to the body 10 and a wide part 14 having an elongated slot 15 to which a strap is secured. The body portion comprises a sleeve 20 having an integral closed end and the other end of which is formed by a removable cap 21. The circumferential wall of the sleeve is cut away in four equally spaced regions 26 to provide the spaces into which the narrow portions 12 of the plates 11 extend. The retracting member is slidably mounted within the sleeve and is in the form of a circular disc 40 having a central hole 41 and four equally spaced holes 42 (not shown) through which pass pillars 23 secured to the integral end of the sleeve. Extending through four further holes 43 in the disc and equally spaced between the holes 42 are four of the bolts 50 each having flat enlarged heads 51 on the side nearest the integral end of the sleeve and trapped between the bolts and the integral end are compression springs 53. The enlarged head of each bolt is provided with two notches which engage the adjacent two pillars so that the bolt is prevented from rotating. The outer ends 54 of three of the bolts are bevelled so that the bolt can be retracted by insertion of a plate 11 in the space. The fourth bolt is longer and its end 55 is square so that the plate 11 associated with this bolt cannot be detached. The shaft 60 extends through the hole 41 in the disc 40 and through a hole 30 in the sleeve, the stud having a head 61 which engages the disc 40 and the other end of which is secured to the rotary operating member. The shaft extends through a tubular external boss 31 on the integral end of the sleeve and this boss is cut away to afford a pair of opposite helical surfaces which form the face cam; rotation of the operating member and hence the shaft causes the pin to ride up the cam surfaces and withdraw the disc 40 and with it the bolts so that the plates 11 can be withdrawn from the recesses. Each cam surface terminates in a recess to retain the pin 65 in the withdrawn position of the shaft. In a modification the cam surfaces on the boss are formed in two sections having an intermediate step so that the operating member has two distinct ranges of movement. The bolts are of different lengths so that two adjacent bolts will be completely withdrawn to release their plates by the movement over the first section, the third bolt being completely withdrawn only when movement over the second section is completed; the fourth bolt is longer and has a square end so that its plate is not released. In a further modification one of the plates can be formed integrally with the cap 21.