A Brake Coupling for Pressure or Vacuum
Page 52
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ACOUPLING that would seem, to incorporate all the features essential to efficiency for both air-pressure and vacuum braking systems has been added to the range of components math by Feeny and Johnson, Ltd., 134-136. Ealing Road, Wembley. Reference to the accompanying drawing will show that the seating washer, which is spring-loaded, has a winged-type guide against which the tapered tailpiece of the coupling abuts.
In the running position, therefore, the seating washer is pushed off its seating to give a free passage from the pressure or vacuum control valve to the brakes. A feature of special interest is the rubber sealing ring, which has an annular groove formed in one of its sides. Under vacuum, this ring maintains a seal by reason of its natural resilience; under pressure the ring is pushed out-. wardly towards the areas with which it is in contact, so that the higher the pressure within reason; the better the seal.
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Surrounding the body of the coupling is a sleeve which encompasses a number of balls fitting into a semi-circular groove formed in the tapered tailpiece. With the sleeve to the right, as shown in the top section of the tailpiece drawing, the balls are retained in the groove in the tailpiece and therefore the tailpiece cannot be withdrawn.
To uncouple the trailer pipe the sleeve is moved to the left until the rec::.ss formed in its back end comes over the balls. The tailpiece is now free to be withdrawn and immediately this is done, the spring behind the main sealing washer forces the washer on to its seating to seal the pipe line.
The body and sleeve are fitted with a safety device, so that the sleeve cannot inadvertently be moved to a position which will allow the tailpiece t.-1 withdrawn.