GB1123911A - Improvements in head and jaw releasable fastenings - Google Patents

Abstract

1,123,911. Push-pull catches. MATTHEW HARVEY & CO. Ltd. 1 March, 1967 [1 March, 1966], NO. 8825/66. Heading E2A. A releasable fastening comprises an element 10 having a head portion 13 and a neck portion 14, the element being adapted to be secured to a member, and a pair of jaws 30 spring pressed towards a partly closed position in which their inner faces 31 define an opening shaped to engage the head portion, the jaws being adapted to be secured to another member to which the first member is required to be releasably fastened, the head portion and jaws being so shaped that the former can be pressed between the latter, opening them against the spring pressure and upon being pressed fully home between the jaws permitting them to return to the partly closed position with the neck portion disposed between their ends so that the head portion cannot be withdrawn by the same path except against the spring pressure, each jaw near its inner and being separately pivotally connected to an attachment element 21, the pivotal axes of the jaws being parallel to each other spaced apart and wherein at a position adjacent to their respective pivots the jaws are provided with portions 33, 34 interfitting with each other under said spring pressure when the head portion is withdrawn from between the jaws, to establish a centralized or other predetermined angular position of the jaws collectively relatively to the attachment element to which they are pivotally connected the interfitting portions and the remaining portions of the jaws being identical with each other to permit of formation of each jaw from the same mould or pattern by a moulding or casting operation or from dies by a pressing operation. In the construction shown the portion 33 is a projecting male part of triangular shape while the portion 34 is a female part V-shaped in cross section, the included angle being equal or approximately equal to the apex angle of the male part 33. Each jaw has a male part and a female part. The spring pressure is provided by two compression springs 26 which, each as shown, extending between a lug provided by each jaw and the attachment element 21; each spring is retained in place by a recess in the attachment element and a projection on the face of the lug or vice versa. As shown the attachment element consists of a plate from which lugs 23 extend the pivot pins for the jaws passing through openings in the lugs; the openings shown are disposed at the same distance from the plate but in a modification one pair of openings for one of the pivot pins could be disposed at a greater distance from the plate than the openings for the other pivot pin so that the jaws collectively establish a non-centralized but predetermined angular position when the head portion is removed from between the jaws. A cover (not shown) having an opening through which the jaws 13 protrude can be provided, this being detachably secured to the plate by the engagement of inturned lips at the edges of the cover with ribs at the ends of the plate. The cover can alternatively be secured by screws. In a modified construction attachment element is modified so that the jaws are pivoted on one side of the plate and pass through an aperture in the plate to the other side, the springs 26 in this construction engaging in deep recesses within stems protruding from the rear of the plate. In both constructions the compression springs can be replaced by a torsion spring. In a further construction the attachment element is in the form of a box-like housing having an opening to allow the head portion to pass into the interior to engage between the jaws.