Patent GB-1032571-A (GB)
Title: Improved device for connecting and disconnecting a parachute to and from a load
IPC: B64D17/38
Filed: 1963-03-25
Abstract: 1,032,571. Hooks. AIRCRAFT MATERIALS Ltd., G. H. GOULD, S. S. COWAN and J. H. E. RUSSELL. March 25, 1964 [March 25, 1963], No. 11739/63. Heading F2H. A device for connecting and disconnecting a parachute from a load comprises a housing adapted to be attached to the parachute or to the load, a hook member pivotally mounted in said housing for engaging the load or said parachute, means for retaining said hook member in a load engaging or a parachute engaging position in the housing, means for holding said retaining means operative means for withdrawing said holding means to permit said hook member to rotate to release the load or parachute on being relieved of the pull thereof, and a gas bellows device for delaying the withdrawal of said holding means. In the construction shown in Fig. 1 and 2 the means for retaining the hook member in its load or parachute engaging position is a rotatable drum 15 which has a pin 16 engaging an arm 14 of the hook member 12 to retain the hook member 12 in said position, the drum being biased by a spring 17 so that it tends to rotate anticlockwise. When the parachute is supporting a load the pull of the load tends to rotate the hook member anticlockwise, keeping the arm 14 in engagement with the pin 16 and preventing rotation of the drum 15 under the bias of its spring. When, however, the load reaches the ground its pull is relieved and no longer prevents the spring 17 rotating the drum since the hook member can rotate clockwise to a limited extent; the pin is therefore moved away from the arm and a pull on the housing will cause the hook member to rotate anticlockwise to release the load or the parachute. The holding means comprises two slidable plungers 18 each plunger being carried by a plate 19 and each being slidable in a wall of the housing and engaging a keyhole slot in a flange of the drum 15. When the pull of the load is initially applied to the hook member 12 it causes it to rotate anticlockwise to a small extent and its arm 14 bears on the pin 16 and rotates the drum 15 clockwise until each plunger is positioned adjacent the large aperture 15d of the keyhole slot. The plungers are then moved through the slot by means of a spring 21 positioned between the two plates 19, the movement being controlled by a bellows 22 and valve 24 of the gas bellows device which allows the air in the bellows to be released slowly. In a second construction, a similar drum 15, pin 16 and spring 17 are used but instead of plungers the drum is provided with open-ended slots in its flanges which receive a pin on the end of a lever, the lever being connected by a link with a second lever which is connected to the spring 17. The slots have detents which normally retain the pin in the slots. Movement of the lever is delayed by a bellows and a valve of the gas bellows device. Operation is similar to that of the previous embodiment in that when the pull of the load is initially applied to the hook member it is rotated sufficiently to allow slight rotation of the drum sufficient to release the pin from the detent. The bellows then allow the pin to withdraw slowly from the slots under the urge of the spring 17. In a third construction, Fig. 7, the hook member 58 pivotally carries a lever 59 adjacent one end a spring 61 holding a face 59a of the lever 59 in engagement with a face of a recess 55a in the housing before the parachute is deployed and while the pull of the load is applied to the hook member; this lever constitutes the retaining means. When the pull of the load is initially applied to the hook member it rotates anticlockwise to a small extent and causes the lever 59 to pivot clockwise so that it engages an abutment of the housing so that the face 59a of the lever is still in engagement with the face of the housing; the spring 61 is stressed by this rotation of the lever 59. The means for holding the retaining means in its operative position is a plunger 45 connected to a bellows 46 of the gas bellows device. The hook member 58 has a detent 58b which before the pull of the load is applied to the hook member is engaged in a groove 45a of the plunger 45; when the pull is applied to the hook member the rotation of the hook member disengages the detent from the plunger and frees the plunger so that it is slowly drawn upwardly by the emptying of the bellows through a valve under the urge of a spring 62. Once the plunger is out of the path of the hook member 58 the spring via the lever 59 can rotate the hook member clockwise immediately it is no longer pulled by the load, i.e. when the load touches the ground. This rotation frees the lever 59 from the face 55a of the recess and the hook member is then rotated anticlockwise by the spring 61 to release the load. The valve associated with the bellows in this construction comprises a needle 48, Fig. 5, which is tapered for changing the size of a discharge space 53 in accordance with temperature, the needle being mounted in a compensating rod 49 of synthetic resinous material, the length of which is determined taking into effect its coefficient of expansion; initial adjustment of the position of the needle is effected by shims 51.