GB101153A - Improvements in Air Brakes. - Google Patents

Abstract

101,153. Pieper, H. Aug. 12, 1915, [Convention date]. Fluid-pressure; electric and magnetic. -The brake piston serves as a pump piston during its return or release stroke and restores the air to its original pressure after an application of the brakes. The return movement of the piston is effected by an electric motor or solenoid acting directly upon the piston rod. The usual compressor or equivalent is thus dispensed with but a feed pump may be added to make up for leakage. The brakes may be applied by regulating the current in the piston solenoid or bv an electrically controlled or other valve. The system may be applied either to compressed air or vacuum working. According to one arrangement, Fig. 1, the return stroke of the brake piston 2 is effected bv the solenoid 13 and the air is returned to the reservoir 1 past a non- return valve 18. A valve 17 for admitting the compressed air to the brake cylinder is normally held closed by fully energizing the magnet thereof. The solenoid 13 and valve 17 are controlled by a switch 20 connected to the line-wire L. The brakes may be applied by moving the switch from the normal mid position gradually to the right so as to introduce the resistances 22 into the circuit of the valve 17, the piston solenoid 13 which is connected to the contacts 23 being deenergized at this time. Release is effected by returning the switch arm back and beyond the mid-position over the con. tacts 22 and 23 so as to fully energize and hold closed the valve 17 and gradually energize the solenoid 13. The brakes may instead be applied by regulating the current in the solenoid 13 with the valve 17 de-energized and free to open. For this purpose the switch arm 20 may have a second arm 11 and to apply the brakes the arm 20 is moved quickly to the right to break the valve magnet circuit and to engage the switch arm 11 with the first of the piston solenoid contacts 23 whereby this solenoid is fully energized and the brake piston held in its initial position. By moving the switch arm farther to the right and traversing the arm 11 over the contacts 23 the solenoid current is gradually weakened and the piston 2 is permitted to move under the influence of the air-pressure in the reservoir. According to a modification a single valve suffices both for supply and return of the air. The circuit of the piston solenoid 13 may remain closed in the normal, mid-position of the switch arm 20 and a second switch be arranged in this circuit adapted automatically to be broken at the completion of the return stroke of the piston. If owing to leakage of air into the brake cylinder the piston should move, this second switch becomes closed and the piston is thus returned to its initial position. A feed-pump may be provided to compensate automatically for leakage of air from the system. The piston of this pump may be actuated by the brake piston rod and be adapted to force air into the reservoir at each return stroke of the brake piston. The series of solenoids 13 and valve magnets 17 on a train may be connected either in series or parallel circuits. The breakage of the leads or the stoppage of the line current applies the brakes. According to the Specification as open to inspection under Sect. 91 (3) (a) the reservoir 1 and valves 17 may be dispensed with and the expansion and compression of the air in the brake cylinder in applying and releasing tha brakes be controlled simply by the piston solenoid which is normally energized. Fig. III (cancelled) shows an arrangement of this character in which however the solenoid is normally de-energized and the piston is held in the release position by a normally energized catch device 6. In applying the brakes the switch arm 10 engages the contact 12 to fully energize the solenoid before de-energizing the catch device by leaving the contact 11. The solenoid current is then gradually weakened by moving the switch arm over the contact 14. The catch device 6 on the valve 17 Fig. 1 may be held in the engaged or closed position respectively by mechanical or pneumatic instead of electro-magnetic means and the breakage of the tube or other connexion may be arranged to effect the applica. tion of the brakes. This subject-matter does not appear in the Specification as accepted.