Patent GB-354915-A (GB)
Title: Improvements in and relating to brake arrangements for trailer vehicles
IPC: B60T7/20
Filed: 1930-06-11
Abstract: 354,915. Brake-operating mechanism for trailer vehicles. HUTCHINGS, H.B., 5, Elm Road, Winchester, Hampshire. June 11, 1930, No. 17911. [Class 103 (i).] In an automatic braking mechanism for tractor and trailer vehicles of the type in which movement of the tractor forward or backward relatively to the trailer releases the brakes on the trailer, while movement of the trailer forward or backward relatively to the tractor applies the brakes on the trailer, the brakes are applied by means of cables or rods, and the arms, levers, or the like for actuating the cables or rods are carried on the coupling- rod or rods. The tractor coupling rod 4 is slidably mounted in bearings 2, 3, Figs. 1 and 2, on the drawplate 1 and is pivoted to the trailer coupling rod 6, which slides in bearings 18, 19 on the towing pole 20 of the tractor. Helical springs 8, 9 on the rod 4 bear against the drawplate 1 and against an adjustable collar 7 and a shoulder 10 respectively, and springs 21, 23 on the rod 6 act on the bearing 18 and on a shoulder 22 and adjustable collar 24 respectively. An arm 11 rigid with the bearing 2 is adapted to coact with a lever 12 pivoted on a collar 13. A push-rod 14, Fig. 2, sliding in brackets 15, 16 on the bearings 2, 3 engages the forked end of a rod 25 sliding in bearings 26, 27 on the towing pole, the rear end of the rod 25 contacting with the end of a rod 28, Fig. 3, sliding in lugs 29, 30 in a bracket 31 secured to the towing pole 20, a collar on the rod being acted on by a compression spring 35. Fixed to the rear end of the rod 28 is a member 32 the ends of which are connected by cables or rods 33 to the brake-levers on the trailer and a member 36 on the forward end of the rod 28 is connected by cables 37, 37a to the ends of a lever 38, Fig. 1, having a pin-and-slot connection 39 with the towing pole and a pivotal connection 40 with the coupling rod 6. Normally the spring 35 maintains the brakes applied as in Fig. 2. If the tractor moves forwards relatively to the trailer the arm 11 on the drawplate engages the upper end of the lever 12 and swings the latter anticlockwise thus moving the rods 14, 25, 28 to the right to compress the spring 35 and release the brakes. On relative movement of the tractor back. wards the bracket 15 engages a stop 17 on the rod 14 and the brakes are released in a similar manner. When the trailer moves towards the tractor the lever 38 is swung anticlockwise and the brakes are applied by the resulting tension on the cable 37a, while if the trailer moves back from the tractor the lever 38 swings clockwise tightening the cable 37 and thus again applies the brakes. When the tractor and trailer are disconnected the brakes may be operated by a lever 41. In a modification, Fig. 7, the trailer coupling-rod 6 slides in a bearing 65 on the towing pole 20 and carries springs 68, 70 acting on the bearing and against a boss 69a, on an arm 69 secured to the rod 6, and a collar 71, and, together with a rod 66 rigidly secured to the towing pole, slidably supports a block 72. The upper ends of levers 75, 76 on a lug 73 on the block 72 coact respectively with a pin 77 on the boss 69a and with a pin 78 on a collar 79 on the rod 66, while the lower ends of the levers 75, 76 coact with a stop 80 on the brake operating rod 81. Levers 83, 84 are connected by a pin-and-slot arrangement 87 to a lug 82 on the block 72. The upper end of the lever 83 coacts with a rod 88 rigid with the bearing 65 and the lower end of the lever 84 coacts with the stop 80. The brake operating rod 81 is acted on by a compression spring 92. If the tractor moves forwards relatively to the trailer the arm 69 engages the stop 80 and moves the rod 81 to release the brakes while if the tractor moves back relatively to the trailer the pin 77 on the boss 69a swings the lever 76 so that the lower end of the lever engages the stop 80 and again releases the brakes. If the trailer moves forwards relatively to the tractor the rod 88 on the bearing 65 abuts the upper end of the lever 83 and causes a clockwise movement of the lever 84 which moves the stop 80 to apply the brakes while on relative movement of the trailer backwards the stop 78 on the collar 79 on the rod 66 contacts with the upper end of the lever 76 and moves it so that its lower end engages the stop 80 and applies the brakes. When the vehicles are at rest and when they are disconnected the stop 80 is held by the arm 69 and the lever 84 so that the brakes are applied, while the spring 42 is sufficiently strong to apply the brakes if the vehicles are suddenly parted. In some cases the springs may be replaced by pneumatic or hydraulic buffers.