Patent GB-1081117-A (GB)
Title: Improvements in or relating to fastening devices
Inventor: BASNETT JAMES THOMAS
IPC: B64D17/38
Filed: 1965-05-14
Abstract: 1,081,117. Parachutes. G. Q. PARACHUTE CO. Ltd. April 25, 1966 [May 14, 1965], No. 20368/65. Heading B7G. [Also in Division E2] A fastening device, e.g. for a parachute, comprises a pair of members 11, 12 one of said members 11 carrying one or more pistons 38, 39, or similar movable units, which enter a housing 30 carried by the second of said members 12 to hold the said members together, means by which the or each piston or similar movable unit is moved manually, and other means by which the or each piston is moved to disconnect the said piston or pistons or similar movable unit or units from the said housing to release the two members of the fastening device. In the construction shown there are two pistons 38, 39 carried by the member 11 in cylinders 18, 19, and the housing is in the form of a block 30 which has a T-shaped chamber drilled in it, the bar 32 of the T- shaped chamber accommodating adjacent end portions of the pistons 38, 39 and the stem 47 of the chamber being arranged to hold a detonator 31 which constitutes part of the second means for releasing the two members; the detonator is fired by batteries 34, 35 which produce a current when immersed in water, the water being able to reach the batteries through holes 21 in the member 11; the firing of the detonator pushes the end portions of the pistons out of the block 30 and at the same time the detonator is pushed against a cam surface 51 on the member 11 to positively move the two members apart about their hinge 13. This movement is assisted by gas escaping out of a discharge hole 33 into the space between the two members. Either of the batteries is sufficient to provide enough current to operate the detonator. The manual release means comprises rods 40, 41 upon which the pistons slide under the pressure of the gas, breaking a shear pin before they can move. Each of the rods 40, 41 is carried by a respective L-shaped plate 42, 43 which plates are retained in position on the member 11 by a plate 26 screwed to the member 11; the plates 42, 43 can slide relative to the member 11 and to each other and when they are moved apart by triggers 24, 25 connected to them, the rods 40 and 41 move the pistons out of the block 30 so that the two members can be moved apart. Ball catches 44, 45 are provided which retain the pistons either in the positions of engagement with the block 30 or in their release positions. The triggers 24, 25 are so connected to the plates 42, 43 that they must be moved towards each other to move the plates apart and this movement is normally prevented by a lift block 22 mounted on the upper side of the member 11; the block can be lifted out of the path of the triggers 24, 25 when it is desired to move them together. The hinge pin 13 connecting the two members together at one end also carries a link 14 by which a strap 15 is connected to the fastening device; another strap carrying link 16 is held between the two members 11, 12 when they are in their closed position; as shown, the link 16 has a bar 46 which is engaged between the two members, the members having openings 52, 53 in their end walls for the stem by which the bar is connected to the remainder of the link. In a modification, a loop type of link is used and the member 12 has side openings to enable the link to be engaged with it. Instead of the detonator being fired by a battery it could be fired by barometrically operated or time controlled means contained between the two members or elsewhere, or electrically under manual control by a parachutist. Instead of using pistons, similar units of other than the normal disc-like shape of pistons can be used.