Patent GB-375661-A (GB)
Title: Improvements in parachute rip cord apparatus
IPC: B64D17/54
Filed: 1931-10-21
Abstract: 375,661. Pack parachutes. IRVING AIR CHUTE CO., Inc., 372, Pearl Street, Buffalo, New York, U.S.A. Oct. 21, 1931, No. 29271. Convention date, May 1. [Class 4.] A pack parachute incorp'orates a rip cord which may be operated either manually or automatically by a spring operated winding drum tripped by time controlled means. Rip cord mechanism B, Fig. 6, which includes manual release handle 31 and clockwork operating mechanism 32 is mounted on the aviator's harness and serves in operation to withdraw pins 27 retaining the flaps of a container 25 in their closed position. The rip cord 28, Fig. 2, comprises wires 29, 30. Wire 29 is passed into a hollow arm 46 of the handle 31 and is provided with a nipple 55 which contacts with a shoulder 52 when the handle is pulled away from clips 45 to effect manual release. When the rip cord 30 is pulled by the winding mechanism the portion 29 is fed into the tubular part of the handle as shown, avoiding external slack. Rip cord portion 30 is passed through a guard tube 35 on to the barrel of a winding drum 70, Figs. 8 and 11, contained in an aluminium case 33. The case comprises a base 60, cylindrical wall 61 and a removable cover 62. A clock work supporting frame comprises plates 66, 67 spaced by posts 68 and providing bearings for the shafts and spindles of the mechanism. Winding drum 70 has connected to it a spiral spring 74, Fig. 11, which is anchored to an adjacent post 68. A gear wheel 77 is keyed to the drum. The drum is normally prevented from rotating by a detent lever 78 pivoted at 79 and held in engagement by a spring 82. Tripping mechanism for lever 78 comprises a shaft 84 carrying a cam sleeve 85 and a ratchet gear wheel 90. The gear wheel 90 is urged to rotate clockwise by a spring 86 but is normally prevented from doing so by a catch 103 pivoted on a spindle 100 having an external handle 101, Fig. 3. Rotation of the wheel 90 is controlled on release by lever escapement mechanism comprising escapement wheel 92, pallet carrying lever 95 pivoted at 96, balance wheel 98, and hair spring 99. Hair spring 99 is so adjusted that the axis of the balance wheel, its eccentric pin 97 and the pivot 96 are normally in alignment so that immediate start of the mechanism is ensured on movement of lever 101. The setting device for cam sleeve 85 comprises an arm 87 pivoted at 84 and operatively connected with ratchet wheel 90 by a spring detent 91 associated with a segmental strip 105 guided in tracks 106, Fig. 12, and fitted with a button 111 passing through a slot 110 in the case. The time taken for release after movement of lever 101 depends upon the angular setting of lever 87 which governs the position of the cam 85 hence the external face of the strip 105 may be graduated in seconds, the numeral being visible through a window 112. To obtain finer adjustment of release time the lever 78 is bifurcated and fitted with a spreading screw 221. The lever 101 is provided with a spring plunger engaging in recesses in the face of the case as shown in Fig. 3. This lever may be operated automatically by a frangible cord 211 connected to the aircraft and passed through a guide 213. The pawl 78 may be moved non-automatically in emergency to release the winding drum, by means of a button 115, Fig. 3, projecting through a hole in the case and connecting to pawl 78 at 117. The invention may be applied to dropping of cargo.