| 摘要 |
1,210,685. Compressed-air braking systems. COMPAGNIE DES FREINS ET SIGNAUX WESTINGHOUSE. 13 Dec., 1967 [23 Dec., 1966], No. 56620/67. Heading F2F. Brake control apparatus includes means to selectively generate fluidic pressure pulses, and means to apply the pulses to means responsive to them, to gradually modify a fluid pressure level which determines the degree of application of the brakes. For a normal brake application, as shown, a push-button valve 6 is operated to admit pressure to the input 5 of a fluid oscillator OS which produces pulses at its output 4. These are applied to an input 2a of a distributor 2 which vents the brake reservoir 1 to the atmosphere for the duration of each pulse. The brakes are thus gradually applied for as long as the pushbutton 6 is depressed, and a bi-stable device BD is held in a state inhibiting emergency brake release (see below). For normal release of the brakes, a similar push-button 9 is operated to cause a second fluid oscillator OD to apply pulses to a second input 2b of the distributer. The brake reservoir 1 is then recharged periodically from the main reservoir (not shown) via a reducing valve 3, and a second bi-stable device BS is held in a state inhibiting emergency brake application. The latter is initiated by a pushbutton valve 12 which admits fluid to input 11 of the bi-stable device BS and changes it to its other state when it delivers a steady pressure to the input 2a of the distributer. The reservoir 1 is then vented continuously to the atmosphere even though button 12 is released. As long as button 12 is pressed, fluid is also admitted to the oscillator OS via a one-way valve 13 and to the bi-stable device BD, augmenting the effect of bi-stable device BS and inhibiting brake release. Emergency braking is stopped by operating button 9 or 17. The latter sets the bi-stable device BD and a further bi-stable device BDS, the former operating oscillator OD as above and the latter providing a supplementary pressure to valve 3 to accelerate recharging of the reservoir 1. The valve 3 also supplies a timing reservoir 23 through a choke 24, and when this is recharged it resets the bi-stable device BDS. If not all the above functions are required, some or all of the bi-stable devices can be omitted. A further control may be provided on the distributer 2 to vent the reservoir 1 to the atmosphere if the supply to the oscillators and bi-stable devices should fail. |
