Patent GB-1365303-A (GB)
Title: Releasable fastener
IPC: B64D17/38
Filed: 1971-10-28
Abstract: 1365303 Releasable fastenings AEROLEX PRODUCTS Ltd 28 Oct 1971 [29 July 1970] 36755/70 Heading E2A A releasable fastener comprises a housing 1 within which is disposed a rectilinearly movable fastening member, the fastening member being engaged releasably with a locking member 3 having two operative positions the locking member in a first releasing operative position permitting movement of the fastening member in a given direction with respect to the housing such that a co-operating part 8 is disconnectable from the fastening member and in a second locking operative position maintaining the fastening member in a position in which it retains the said co-operating part in fastening relationship with respect to the fastening member in the housing, the locking member being movable against a spring bias from the locking to a releasing operative position by a predetermined force applied between the fastening member and the housing in the given direction. In the construction shown the fastening member has a hook 17 at one end which is engageable with a hook 18 of the co-operating part 8 and at the other end it is formed with a slot 24 which co-operates with the locking member 3; the side surfaces of the slot divert inwardly from its mouth and are also inclined relative to the major surfaces of the fastening member 2; they co-operate with a frusto-conical surface 5 of the locking member 3 such that movement upwardly of the fastening member as shown in Fig. 1 caused by a force between the member 8 and the housing 1 causes the locking member to move to the right as shown in Fig. 2 because of the ramping action between the inclined surfaces 7 and the frusto-conical surface 5 of the locking member. The movement of the locking member takes place against the bias of a rubber spring 11 and sufficient movement to the right of the locking member releases the fastening member 2 which can then move upwardly relative to the housing so that its hook protrudes from the top of the housing enabling the part 8 to be disengaged from the hook 17 when for example the fastener is used for connecting a parachute to a load and the load becomes supported by the ground so that the member 8 becomes automatically detached from the hook 17. Movement of the member 2 upwardly is limited by a sleeve 15 which is disposed in the slot 16 in the fastening member and which is carried on a pin connected to the housing. The load is normally connected to the part 8 and the parachute to the housing the fastener being shown upside down in the drawings. The locking member is carried on a shaft 19 which has a square portion 19A engaging a square hole in the locking member 3 so that turning of the shaft 19 will rotate the locking member, the locking member has two diametrically opposite flats 6 and when the locking member is turned by means of the shaft so that these are opposite the surfaces 7 the fastening member can be moved upwardly as shown to its releasing position in which the part 8 can be engaged or disengaged by the hook 17. A knob 12 is connected to the shaft and between the knob and the housing are four balls located in recesses in the housing and recesses in the knob the balls preventing free movement of the knob and hence of the locking member since the knob is biased into engagement with them by the rubber spring 11.