| 摘要 |
1493687 Antiskid braking systems KELSEYHAYES CO 25 July 1975 [25 Oct 1974] 31307/75 Heading F2F An antiskid braking system includes an operator control in the form of a treadle valve 12 for selectively applying actuating pressure from a source 14 to brake applying means, a regulator 62 for providing a controlled supply of pressure, means responsive to an incipient skid condition for relieving braking pressure to prevent skidding and means responsive to a predetermined wheel rotational condition for applying pressure from the regulator to the brake applying means to re-apply the brakes at a regulated pressure. Operation of the treadle valve 12 supplies pressure to a latch valve 26 normally held open by a spring 29 and thence to a piston 16 of a relay valve 13 so that high pressure air is supplied from a source 14 to brake 15. If a skid signal is received at a control device 43 a solenoid valve 41 is opened to allow air in the relay valve chamber 34 to be dumped to atmosphere. During normal brake application a memory chamber 71 is charged via a restricted orifice 74 and the pressure therein will be related to the control pressure existing during brake application. When the chamber 34 is exhausted to atmosphere the reduced pressure is transmitted to the part of valve 26 below a diaphragm 27 but full pressure is applied above the diaphragm so the valve closes to prevent further treadle valve control pressure being communicated to chamber 34. The pressure in the chamber 71 will gradually bleed off through restricted orifices 74, 76 and when the control device 43 determines that the wheel or wheels has spun up sufficiently for the brakes to be reapplied valve 41 is released and control pressure is delivered to chamber 34 via regulator 62 line 53 and open valve 51. The pressure in the regulator chamber 61 is dependent on the load of the spring 68 and the pressure of chamber 71, and since the pressure in chamber 71 decreases during antiskid operation, the longer the time before reapplication, the lower will be the reapplication pressure, though this will then increase as the pressure builds up again. To regain manual control of the brakes treadle valve 12 is released to allow valve 26 to re-open; the treadle valve 12 may then be operated once more. |
