| 摘要 |
PURPOSE:To prevent the mis-release of a spring brake and improve its safety by providing an electromagnetic device with a lock plunger at a switching valve in the spring brake circuit and locking the switching valve in accordance with the parking operation using this lock plunger. CONSTITUTION:A switching valve 4 is provided between a reservoir 2 and a spring brake chamber 3 and is provided with an electromagnetic device 33. This electromagnetic device 33 is provided with a lock plunger 39. This plunger 39 is always moved left by a spring 45 and is sucked right by the excitation of a solenoid 36. Besides, when the plunger 38 is moved left, its tip 39c is engaged with the groove 23 of a movable valve member 20 of the valve 4. The switching valve 4 is provided with proximity switches 31 and 32 that control the current applied to the solenoid 36 and these switches 31 and 32 are actuated by the operation lever 27 of the switching valve 4. When the operation lever 27 is set to the spring brake actuation position, current is not applied to the solenoid 36. |
