Patent GB-189845-A (GB)
Title: Improvements in brakes
IPC: B60T7/20
Filed: 1921-08-27
Abstract: 189,845. Cole, T. H. Aug. 27, 1921. Actuated by backward pressure of tractor and by weights; force-transmitting mechanism.- In brake mechanism for trailer vehicles whereby the brakes are applied when the tractor force on the draw-bar ceases, the mechanism is locked in the " brakes-off " position by the initial forward movement of the draw-bar and are applied only when the draw-bar moves rearwardiy sufficiently to trip the locking means; the brakes are thus unaffected by oscillation of the draw-bar during travel of the vehicles. The braking force may be provided by springs or by a weight arranged to adjust itself automatically upon a lever according to the gradient upon which the vehicle is travelling. The arm of the lever may be adjusted also to vary the braking force with the load. In one arrangement, Fig. 1, the draw-bar spring d is interposed between a coned nut c<1> on the drawbar c and a sliding frame e connected by the rod g to a lever f pivoted upon the spindle b<3> of the frame b. The lower end of the lever f has a swivelling collar f<1> through which freely passes a screwed spindle k having a stop nut k<1>. The spindle k is connected tc a transverse balance bar l connected by links l<2>, one at each side of the vehicle, to hub brakes n and also to a spring j, the other end of which is connected to a spindle i screwing into a ratchet nut i<1> which abuts against a fixed part h. As shown, the brakes are not applied although there is no traction on the draw-bar c. To set the brakes tension is given to the spring j by the nut i<1> to an extent indicated by graduations on a strip j<2>, and -the nut k<1> is then screwed up against the collar f<1>. When tractive force is applied to the drawbar the frame e is moved forwardly to release the brakes and a catch o engages the cross-bar b' and retains the mechanism in the release position. To effect the application of the brakes, the drawbar must movo rearwards sufficiently to cause the nut c<1> to disengage the catch o. The tensionadjusting means for the spring j may include a windlass which may be the spindle b<3> of the draw bar frame. In another arrangement as applied to a trailer with rear wheel brakes and a swivelling fore-carriage, a lever such as f is mounted upon the spindle b<3> and is connected by rods arranged to pass the. fore-carriage pivot to a brake beam from which extends readwardly the spring connection by which the brake blocks are applied. A weighted lever may be used instead of a spring to apply the brakes, and in one arrangement this lever is connected by a cable to the frame e and also to the balance-bar l. In Fig. 6 a lever u pivoted to the bracket t' is in the form of a curved run-way for a weight u<1>, which thus takes up a position on the lever dependent upon the gradient upon which the vehicle is travelling. The application of the tractive force to the draw-bar raises the arm u of the lever by the connections g, w, u<4>, so that the weight travels to a position near the fulcrum and the brakes are thus released. The connection v<3> from the brake beam v is slidable on the lever arm u<2> and can be held :n position adjusted. according to the load by a chain v<4> passed around a member u<3> on the lever.