Patent GB-855429-A (GB)
Title: Aircraft arresting means
IPC: B64F1/02
Filed: 1957-11-04
Abstract: 855,429. Aircraft arresting gear. ALL AMERICAN ENGINEERING CO. Nov. 4, 1957 [May 22, 1957], No. 34309/57. Class 4. Aircraft arresting gear comprises an arresting cable normally lying on the runway surface and releasably attached to movable supporting means normally disposed below the runway surface, an actuating member supported above the runway so as to engage the nose wheel strut of an aircraft, and a connection between the actuating member and the cable supporting means, so that on the nose wheel strut engaging the actuating member, the cable is raised into the path of the aircraft main undercarriage. In Fig. 1, the runway R has two or more trenches 10 each parallel with the length of the runway and containing a bracket 11 to which is pivoted a stanchion 15 normally in the position shown in full lines. The arresting cable 19 is normally held between the nose 18 of a member 16 pivoted to the stanchion at 17, and a member 20 pivoted to the stanchion at 21. Member 16 is tied to the bracket 11 by a rod 31 pivoted to the bracket and engaged in a recess 24 in member 16. A hook 23 on member 20 engages a loop on a line 26 connected at 27 to one end of an extension spring 28 normally hanging vertically from an actuating cable 30 suspended by stanchions (not shown) across the runway. When the nose wheel strut of an aircraft landing from right to left as seen in Fig. 1, engages the actuator cable 30, the resulting pull on spring 28 and line 26 raises the stanchion 15 to the position shown in chain dot lines. The end of rod 31 is withdrawn from recess 24, and member 16 is free to swing clockwise. The arresting cable 19 is thus raised into the path of the main undercarriage, and freed for movement from the stanchion when engaged by the undercarriage. Member 20 can then swing clockwise, releasing line 26. The stanchion swings forward under its own momentum, and falls into trench 10. Fig. 6 shows an alternative in which the runway R is provided with a number of bores 40 inclined at 45 degrees and in vertical planes parallel to the runway axis. Each bore contains a sleeve 41 narrowing at 44 and formed with a shoulder at 47. The bore contains a cable support 51 having lugs 57 at one end and a part conical piston 50 with a shoulder 65 at the other end. Lugs 57 support a hook 55 retaining the cable 53, in  a pivot 56 and shear pin 58. An actuator strap 64 disposed above the runway is connected through a normally vertical extension spring 63 and a shear link 62 to a line 59 passing down the sleeve 41 and through a bore in piston 50 to a fastening 61 at the base of the piston. The sleeve contains two diametrically opposite guide projections 48 co -operating with grooves in the piston, and is filled with damping fluid 52. When the nose wheel strut engages actuator strap 64, the pull in line 59 withdraws support 51 from the sleeve, the motion being damped by the fluid 52, until shoulder 65 abuts shoulder 47. The cable 53 is thus raised into the path of the main undercarriage. When the latter engages cable 53, shear pin 58 breaks and the hook 55 pivots on pin 56 to release the cable. The shear link 62 also breaks, releasing the actuator strap from connection with line 59.