Patent GB-226524-A (GB)
Title: Improvements in brake operating devices of wheels mounted on pivoted axles
IPC: B60T11/04
Filed: 1924-12-09
Abstract: 226,524. Compagnie d'Applications MÚcaniques. Dec. 20, 1923, [Convention date]. Braking; controlling- apparatus, arrangements of hand and foot gear in conjunction with. - In a steering- wheel brake comprising an operating-cam 8 supported on the steering- swivel, and an operating- rod 9, supported on the axle by a ball-and-socket joint 13 and adapted to actuate the cam through a universal joint 10, the centre of which is outside the axis a of the steering pivot, the parts are so designed and arranged that the steering movements of the wheels with the brakes applied either have no effect on the braking, or increase the brake action on one wheel and decrease it on the other. The brake-operating lever 11, connected at g to the pull rod, is adjustable lengthwise of the rod 9, and in the form shown in Figs. 1, 3 and 4 the axis a, the axis b of the joint 10 about which the rod 9 pivots, and the axis c of the rod 9 are in the same plane. When this is the case, the angle B between the axis a and the axis d of the cam is without effect on the braking, but the angle A between the axes a, c determines what effect steering has on the point g of the rod 11. Fig. 3 shows the angular displacements of the point g during steering, the wheel being presumed fixed and the end of the rod 9 supported on the axle being supposed movable. When, as shown in full lines, the angle A is less than 90‹, steering of the wheels turns the arm 11 through an angle c<1> or c<2> such that the braking effect on the outer wheel increases whilst that on the inner wheel is reduced. On the other hand, when, as shown in dotted lines, the angle A is greater than 90‹, the reverse effects are realized. Fig. 4 shows the movements of the point g in a horizontal plane due to the angular displacements of the wheels during steering, the point g being moved to a position g<1> or g<2> such that the braking effect on the inner wheel is increased whilst that on the outer wheel is reduced. Hence, by suitably positioning the rod 11, the movements of the point g shown in Figs. -3 and 4 may be balanced, so that the steering of the wheels does not affect the braking, or the braking effect on one wheel may be increased, whilst that on the other is reduced. To balance the angular displacement of the point g when the angle A is greater than 90‹, the point g must either be situated at g<3>, Fig. 4, or the pivoting axis a be provided between the points g e. When the axis b of the universal joint is at right-angles to the plane of the axes a, c, the angle A does not affect the braking, but the angle B does, and Fig. 7, which corresponds to Fig. 4, shows that when the angle B is greater than 90‹, the displacements c<5>, c<6> correspond to those c<1>, c<2> of Fig. 3. When, as sometimes happens, the angles A or B are not known until the brake is assembled, means may be provided in the joint 10 to adjust the angular relation of the rod 9 with respect to the cam 8, and therefore the position of the axis b, so that the desired balance between the two motions of the point g may be obtained. For instance, when the joint comprises a spherical member, grooves in which are engaged by pins in a part-spherical housing, the pins may be engaged in any corresponding pair of a number of recesses in the housing. Or, as shown in Fig. 12, one member 22 of the joint may include a toothed portion 24 fitting in a corresponding toothed portion of the cam 8. In further forms the member 22 is provided with two grooves at right-angles to each other in either of which the cam may engage, or an extension of the member 22 may engage pairs of grooves cut in a cylindrical recess in the cam. The lever 11 may be provided with teeth engaging teeth on the rod 9 in order to prevent its accidental rotation thereon, whilst permitting its lengthwise adjustment.