GB740292A - Improvements in and relating to devices for braking vehicles moving over natural ground - Google Patents

Abstract

740,292. Launching and braking aircraft. SOC. NATIONALE DE CONSTRUCTIONS AERONAUTIQUES DU SUD-EST. Oct. 6, 1953 [Oct. 27, 1952], No. 27446/53. Class 4. [Also in Groups XXXI and XXXIV] In a braking device for vehicles comprising at least one hoe-like point which is adapted to penetrate into and frictionally engage the natural ground and secured on the free end of a supportmember pivotally mounted on the vehicle, each hoe-like point is formed with two lateral faces substantially parallel to the direction of motion of the vehicle, and being joined at the front through a pair of symmetrical bevel faces defining a cutting edge. A carriage for launching aircraft is illustrated in Fig. 1 in which the carriage comprises a substantially rectangular frame consisting of side members, a front crossmember 1 supporting front wheels 2, and a rear crossmember 3 with a pair of rear wheels 4. Ahead of the front cross-member 1 the carriage is equipped with a hinged flap 5 which is substantially horizontal, when the carriage supports an aircraft to be launched, and is raised by the action of a resilient device (not shown) to act as an aerodynamic brake. A rope 7, attached at one end to a support 6 on the flap 5, passes over a set of pulleys 8, 9 and 10 and is attached at its other end to a shaft 11 belonging to the device for locking the braking hoe in its retracted position (Fig. 3). In alignment with the centre longitudinal axis of the carriage the latter has rigidly secured thereto a prismatic, substantially triangular supporting tubular structure 12 pointing to the rear. This structure is provided at its rear end with a resiliently-mounted steel skid 13. On a substantially horizontal shaft 15, carried by the lower portion of the structure 12, is mounted a hoe assembly 16. This hoe structure may be equipped with one or more earth-penetrating pointed members or points 30, Fig. 1, showing a three-point mounting and Fig. 8 showing an enlarged cross-sectional view of the profile of a point. In operation, as the aircraft takes off from the carriage, the aerodynamic brake flap 5 is raised and the rope 7 is pulled and the lateral bolts 66 are thus freed from the hooks 71 and the lever 60 turns about the pivot-pin 59 and the hook member 61 clears the hook 43. At this moment elastic cords (not shown) and the inherent weight of the hoe assembly cause the latter to be lowered by pivoting about the shaft 15 from the retracted position to the oblique, operative position shown in. Fig. 1. The penetration resulting from this movement and the carriage motion will rapidly move the hoe assembly to a vertical position, guard plates 32 engaging the ground surface and the points 30 digging completely in the ground to retard the carriage. In this position the plate 45 engages against a shock-absorber unit 52 ; the latter thus being strongly compressed. To raise the hoe assembly, the carriage is moved slightly backward to free the points from the ground and by means of a bar or lever engaging in the sockets 47, 48 the hoe assembly is lifted and locked in its retracted or inoperative position by interconnecting the hook members 43 and 61. (Fig. 3). If the ground clearance of the aircraft is relatively low, a retractable hoe assembly of the above type may be mounted in the bottom of the fuselage hull. Figs. 11 and 12 illustrate an application of this invention to an aircraft equipped with a ski landing gear of the type described in Specification No. 726,573. In the bottom of the hull of an aircraft 79 (Fig. 11) there is provided a pair of retractable landing skids 81a and 81b. Each skid is formed with an inner recess 82 adapted to receive in its rear portion the braking device in its inoperative condition as shown in Fig. 12. This device comprises a socket member 83 pivoted on a pin 84 carried by a rigid supporting member 85, the socket member 83 housing the shank 90 of a curved hoe point 91. When the aircraft has landed on its skids, the pilot controls the hydraulic rams 96 to move the points 91 from the retracted (Fig. 12) to a position in which the points are engaged into the ground. Differential braking may be effected by engaging either one or the other of the points into the ground. In its retracted position, each point 91 is held by its relevant elastic cord 99. Specifications 726,573, 733,830 and 739,814 are referred to.