Patent GB-907964-A (GB)
Title: Improvements in or relating to parachute coupling devices
IPC: B64D17/38
Filed: 1958-10-10
Abstract: 907,964. Time locks; hooks. AUTOFLUG GERHARD SEDMAYR G.m.b.H. Oct. 10, 1958 [Oct. 19, 1957], No. 32431/58. Classes 44 and 89 (2). A parachute coupling device comprises two separable coupling parts one of which is adapted to be connected to the parachute and the other of which is adapted to be connected to the load, means for effecting release of the coupling parts upon a predetermined reduction in the force caused by the load acting between the coupling parts and timing mechanism 5 for delaying the freeing of the releasing means, for operation, one of the coupling parts having a hook portion 9, for engagement by the other coupling part 10 or 34 the releasing means including a slidable latch 15 or 37 for co-operation with the hook portion, and a spring 14 or 35, the latch being slidable into a position in which it obstructs the mouth of the hook portion to an extent preventing the coupling part 10 from passing therethrough and into a position in which such passage is permitted. In the construction shown in Fig. 2 the coupling part 10 is an eye and the other coupling part which includes the hooked portion 9 has a body comprising two sleeves 1, 2 which have screw-threaded interengagement; the lower end of the sleeve 1 is bifurcated and is provided with a withdrawable pin 3 for engagement with the load. The pin 3 is fixed in place by a spring washer. Within the sleeve 2 is the timing mechanism 5 and this mechanism includes a disc 6 mounted on a spindle which extends through a plate 7 which carries the timing mechanism and which serves as a pressure plate against which the disc 6 can abut; the plate 7 is held in position by the screwing together of the sleeves 1 and 2 so that the timing mechanism can be easily removed. The hooked portion 9 is bifurcated and in the space between the limbs of the bifurcation is the latch 15 which is carried by a pin 11 which extends into the sleeve 2 and is secured to a plate 12 with its inner end 13 projecting towards the timing mechanism. Between the plate 12 and the upper end of the sleeve 2 is the spring 14 which tends to urge the pin 11 towards the disc 6; the disc 6 normally prevents the movement of the pin 11 under the force of the spring 14 until such time as an opening in the disc becomes aligned with the end 13 of the pin by the operation of the timing mechanism. The latch is provided with a portion 16 which is disposed so as to obstruct the opening of the hooked portion 9 when movement of the pin 11 is obstructed by the disc 6 and so prevent unhooking of the eye 10 and the engagement of the pin 11 with the disc prevents operation of the timing mechanism; in use, however, the force, caused by the load, acting between the two coupling parts causes a movement of the latch 15 against the pressure of the spring 14 sufficient to disengage the end 13 of the pin from the disc so that the timing mechanism can operate; this movement of the latch is limited by the eye engaging the head portion 17 of the hooked portion 9. When the force between the two coupling parts is reduced sufficiently by, for example, the load hitting the ground and provided that at such time the opening in the disc 6 has become aligned with the pin 11 by the operation of the timing mechanism, the spring 14 acts to move the latch so that the mouth of the hooked portion becomes unobstructed and at the same time the eye 10 is ejected from the hooked portion by the movement of the latch and its engagement with a sloping portion of the hooked portion. The timing mechanism is wound up by means of a key after a cap 20 is removed. The latch is moved to its mouth obstructing position by a crank member which can be screwed into it. To enable the eye to be engaged with the hooked portion when the latch is in its mouth obstructing position the portion 16 of the latch is removable. To make the sleeves enclosing the timing mechanism as fluid-tight as possible a sealing-ring 19 is located between the sleeves 1, 2 and a sealing- ring 18 is provided around the pin 11. If, during the operation of the device, the force acting between the coupling parts falls to a value lower than the force exerted by the spring 14, caused, for example, by initial movement of the parachute canopy, the end 13 of the pin 11 engages the disc 6 and stops the operation of the timing mechanism. In another construction, Fig. 3, the coupling part 34 which engages the hooked portion is also an eye and in this construction the timing mechanism is housed in a body of flat form having a removable coverplate ; the timing mechanism includes a ratchet wheel 31 and the latch 37 is movable between the two limbs of the hooked portion which is bifurcated as in the previous construction. The latch has a stem 38 which normally engages the ratchet wheel 31 to prevent operation of the timer mechanism. As in the previous Construction the stem is withdrawn from engagement with the ratchet wheel when the force acting between the two coupling parts is sufficient to allow the timer mechanism to operate and the ratchet wheel 31 has a recess which becomes aligned with the stem 38 when the timer mechanism has completed its operation and when this happens the eye 34 is urged from the hook portion by the spring 35. A light spring 39 is provided to hold the stem 38 away from the timer mechanism when the force acting between the two coupling parts is sufficient. The body has a removable cap to enable the timing mechanism to be rewound.