. Electric railway journal . es from a twelve-cell dry battery. Push buttonsare installed on posts over the control valve forenergizing the relay through which the cylinder attachedto the shifter is operated. When the operator wishesto raise a car he presses the button which actuatesthe belt shifter and starts the pump. This gives pres-sure to the jacks at once. To supply the pressure forraising the car the operator merely opens a standardj-in. Lunkenheimer globe valve installed between thepump pressure line and the inlet at the base of thecylinder. When the car has been raised to the desiredh
. Electric railway journal . es from a twelve-cell dry battery. Push buttonsare installed on posts over the control valve forenergizing the relay through which the cylinder attachedto the shifter is operated. When the operator wishesto raise a car he presses the button which actuatesthe belt shifter and starts the pump. This gives pres-sure to the jacks at once. To supply the pressure forraising the car the operator merely opens a standardj-in. Lunkenheimer globe valve installed between thepump pressure line and the inlet at the base of thecylinder. When the car has been raised to the desiredheight the valve is closed andthe jack will remain indefi-nitely at the height set. Toprovide for negligence or incase the operator, should becalled away, the travel of thecar hoist is automatically lim-ited to a few inches above theheight ordinarily required forcar horses. This feature isobtained by the simple expe-dient of placing a collar onthe plunger which permits thepressure to continue indefi-nitely without harm. A re-. FIG. 1—VERTICAL SECTION OF HYDRAULIC CAR HOISTUSED AT SAN DIEGO. FIG. 2—METHOD OF SUPPORT-ING PRESSURE GAGE SO AS TO PREVENTFLUCTUATIONS IN PRESSURE INTER-FERING WITH GAGE READINGS lief valve on the pump takes care of any undue rise inpressure. To lower the car a valve is opened, allowing oilto flow from the cylinders into the discharge line lead-ing to the sump. In order to prevent interferenceshould it be desired to raise or lower two cars at thesame time, a check valve is installed in the supplyline. This prevents one man from lowering a carwhile another is in the act of raising one. The construction of the lift may be followed by referring to Fig. 1. The collar C is welded to the plungerA and serves to limit the travel of the same. Themember L is to limit the downward travel and is con-
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