Patent GB-516292-A (GB)
Title: Improvements in or relating to parachutes
IPC: B64D17/04
Filed: 1938-06-28
Abstract: 516,292. Parachutes. THORNBLAD, A. R. June 28, 1938, No. 19125. Convention date, June 29, 1937. [Class 4] A parachute is composed of at least two component parachutes, a main parachute, and an auxiliary parachute adapted to open first and pull the main parachute from its container into an elongated and only partly spread condition, the top of the main parachute being freely movable with respect to the suspension lines of the auxiliary parachute so that it can spread independently of the tension of the suspension lines of the auxiliary parachute when the latter has sufficiently retarded the descent. An auxiliary parachute 2 is connected by lines 5 to a load-supporting cable 6, and lines 12 connected to a large vent of the main parachute 3 pass through rings 10, secured to the cable 6, and are anchored to a slide 11 acted upon by a spring 9 surrounding the cable. Before the lines 7 of the main parachute are withdrawn from their pockets the parachute 2 raises the rings 10 and the lines 12 draw the upper edge of the main parachute from its pack, at the same time compressing ,the spring 9. As the lines 7 are pulled out the main parachute rises with respect to auxiliary parachute but it remains elongated with the spring 9 compressed until the speed and therefore the pressure is sufficiently reduced to allow the spring 9 to expand and draw down the top of the main parachute to permit it to spread. A smaller pilot parachute 1 which forms the cover of the parachute pack is connected to the vent of the parachute 2 by draw-strings 4 which slacken as the speed is reduced. When folded, the main parachute rests upon a rigid base 8 and is retained thereon by two straps 24, Fig. 3, secured together by a clip 25 adapted to be released by the pull of the cable 6 and lines 12.' The parachute 2 rests upon the main parachute where it is retained by two strips 22 looped together and secured by inserting a loop of the lines 4 and is covered by the parachute 1 which has eyelets secured over pins 17 on flaps 18 on the base by wires 19 connected to a release cable 21. Spring hinged flaps 15 ensure the spreading of the parachute 1. Numerous modifications are described. The lines 12 may themselves be made elastic and the spring 9 dispensed with, and the lines 4, 5 also may be elastic to draw the three parachutes closer together as the speed falls. For the same purpose the lines 5 and' 7 may be continuous and be passed through rings, adjacent to the load, limit stops being provided on the lines. The various lines may be secured to separate points on the main cable 6, or lines from the top edges of the parachutes 2, 3 may be connected to the main supporting lines of the next higher parachute. The top edge of the. main parachute may have rings which slide on the lines of the auxiliary parachute, stops on the lines ensuring the initial withdrawal of the main parachute. Breakable connections or releasable clips may be employed to ensure the initial restrictions of the openings. The three parachutes may lie one within the other at the same level instead of being superposed. A drift vane may be provided in the rigging. In the Specification as open to inspection under Sect. 91, other arrangements of springs acting on the lines 12 are described. This subject-matter does not appear in the Specification as accepted.