Patent GB-330993-A (GB)
Title: Improvements in apparatus for lowering mail bags and other loads from air-craft
IPC: B64D1/02
Filed: 1929-03-23
Abstract: 330,993. Holt. H. E. S. March 23, 1929. Parachutes.-Relates to apparatus for lowering mail bags and other loads from aircraft, of the kind in which the rate of descent of the load is controlled by main and pilot parachutes, means being provided under the control of a pilot weight lowered from a rotary drum or reel whereby the main parachute can be kept inoperative until it reaches approximately a given distance from the ground which is determined by the length of a cable formed with insulated conductors to which the pilot weight is attached, the pilot weight being provided with circuit closing means adapted to be: operated by impact with the ground. According to the invention the rotary drum 1 carrying the line 2 with its attached pilot weight 3 is mounted on the fuselage 7 of the aircraft and means are provided for electrically coupling the line 2 to the launching apparatus 10 after the lowering of the pilot weight 3 and the complete unwinding of the line 2 from the drum 1; these means taking the form of pin and socket connectors 11 and 12, Fig. 1. Means are also provided for releasing the main parachute and bringing it into operation independently of the action of the pilot weight 3 when the aeroplane is flying low. The launching apparatus 10, Fig. 1, is carried by a cradle 14 from which it can be released by a lever 35. The pilot parachute 18 is carried in a container 19 attached to the cradle 14 whence, it is pulled at launching by a line 20 connected to the frame of the load carrying apparatus 10 through a releasable coupling. The main parachute is retained in a folded condition in a container 15 by flaps held closed by a withdrawable pin 16 and a breaking cord 17 both of which are connected by lines 21 and 22 to the line 20 of the pilot parachute. The releasable coupling referred to above consists of a fixed jaw 23, Fig. 3, and a jaw 24 formed on a lever 25 pivoted at 26 and normally retained by a pivoted catch lever 27. A loop or eye on the cables 21 and 22 is normally retained between these jaws. Means for effecting release of the jaws 23, 24 and thus permitting the withdrawal of the main, by the pilot parachute comprise small projectiles 31 which are adapted to be driven against the undersurface of an extension 32 on the lever 27 by the ignition of cartridges 33, upon the establishment of an electrical circuit by the deformation of the pilot weight 3 upon reaching the ground. The alternative means are shown in Fig. 2 in which 41 and 42 form a slip coupling connected to an extension 32 of the catch lever 27 and to a cord 40 provided with two heads or enlargements 43 and 48. The head 43 is held in a tube 45 on the launching cradle 14 by a spring catch 44 and the head 48 similarly is held in a tube 50 in the frame 10 by a catch 51 which is stronger than the catch 44. Normally on release of the apparatus the cord 40 is extended and the head 43 pulled clear of the cradle but when the main parachute is to be released immediately, the head 43 is positively retained by a sliding bolt 46 actuated by a hand lever 36 shewn in Fig. 1. In this case when the cord 40 is extended, the head 48 is freed and the catch lever 27 operated through the slip coupling 41, 42 which disengages automatically to free the cord 40. The electrical circuit of the apparatus is shewn diagrammatically in Fig. 4. The conductors 62, 65 are contained in the cord 2, Fig. 1, and the conductors 72, 73 in the cord 9. An insulating jack 85 inserted between spring contacts 81, 83 is anchored by a cord 86 to the cradle 14 and prevents accidental completion of the circuit. The pilot weight 3 comprises a central weight 58 enclosed in and co-operating with a resilient displaceable member 59 and a deformable member 60 normally spaced and insulated one from the other. The launching operation when delayed action is required is as follows :-The weight 3 is allowed to fall to unwind the cable 2; the coupling member 11 is disengaged from the drum and engaged with the member 12, which is disengaged from the spring clip 90 and held by a cord, not shewn, secured to a loop 91 formed in the. cable, which cord is paid out slowly to allow the weight 3 to draw out the cable 9 through the eye 89; and finally the lever 35 is actuated to release the load 13 from the cradle 14. When the load is to be launched from a low altitude the hand lever 36 is first operated to project bolt 46 into the tube 45, cable 9 is then released from the clip 90 and finally the hand lever 35 is operated to release the load. The load lowering apparatus 10 is adapted to be disposed between two mail bags 13 or other packages leaving a space at the forward end for the container 15. A small braking parachute may be attached to the weight 3.