Patent GB-376126-A (GB)
Title: Improvement in parachute rip cord apparatus
IPC: B64D17/54
Filed: 1931-10-21
Abstract: 376,126. Pack parachutes. IRVING AIR CHUTE CO., Inc., 372, Pearl Street, Buffalo, New York, U.S.A. Oct. 21, 1931, No. 29270. Convention date, Aug. 19. [Class 4.] Rip cord operating mechanism for a pack parachute comprises a handle for manual operation and means carried by the handle for exerting a pull on the rip cord automatically and independently of the handle. Fig. 2 shows a conventional pack parachute having a rip cord 28 connected to a handle 34 comprising a hand-grasping-bar 35, side bars 36, 37 and a rectangular case 40 forming part of the handle and which contains time controlling mechanism mounted on a detachable frame 52, Fig. 6. Frame 52 comprises plates 53, 54 spaced by detachable parts 55. Rip cord 28 is secured to and adapted to be wound on a drum 60 keyed upon a rotatable shaft 61 bearing in plates 53, 54. A spiral spring 62 is keyed at its inner end to shaft 61 and is anchored to an adjacent post 55. This spring is shown coiled in Fig. 4 with the rip cord unwound from the drum. A gear wheel 70 forming one flange of drum 60 is operatively associated with an escapement mechanism and an intermediate detent operated by the escapement mechanism for releasing the drum after a predetermined time interval to permit the spring 62 to wind the rip cord cable on the drum and release the parachute. The detent mechanism comprises a mutilated gear wheel 75 mounted on a shaft 77 and adapted to mesh with gear 70 for a part revolution then to disengage and leave the latter free to rotate under the constraint of spring 62. A gear wheel 82 also keyed to shaft 77 engages a gear wheel 81 keyed to a shaft 80 upon which is rotatably mounted a gear 85 operatively connected to the shaft by a pawl and ratchet mechanism so as to key gear 85 with shaft 80 when there is a tendency for spring 62 to rotate shaft 80. The escapement mechanism proper comprises an escapement wheel 91 mounted on a shaft 90 which also carries a bar pinion 92 meshing with gear 85. An escapement lever 93 is mounted on a bar 94, Fig. 6, arranged to oscillate between bearings on plates 53, 54. Escapement wheel 91 is normally held from rotating under the influence of spring 62 acting through the gear train described by means of a detent arm 104 held in engaged position by a finger engaging snap 105 extending through the casing 40. Movement of this member 105 by the aviator to the " on " position, Fig. 3, disengages detent 104 permitting step-by-step rotation of the escapement wheel 91 until such time as the mutilated gear 75 ceases to engage with the drum gear wheel 70 and permits free rotation of the winding drum. Shaft 77 carries a time re-setting wheel 78 mounted so that. a segment thereof projects through casing 40. The periphery of the wheel is graduated on a time scale. The initial position of this wheel since it governs the angular position of the mutilated gear wheel 75 governs the time taken for the latter to rotate out of mesh with gear 70, i.e. the time taken for release of the parachute from the instant of moving the finger snap 105 to the " on " position. Setting the apparatus is accomplished by pulling on rip cord 28 to wind the spring 62 then engaging gear 75 in the appropriate position as determined by a setting mark 111, Fig. 3, and then engaging detent 104. A hammer 96 is operated by the escapement lever 93 continuously to strike a bell 97 during functioning of the mechanism. Handle 34 and case 40 are normally housed in elastic pocket on the aviator's harness. A modification is described in which the shaft 61 of the winding drum is adapted to receive a winding key.