fluid flows into the line 26 and further, through the four-way valve 21, into the return ducts 20 and back to the storage tank 18.
In order to also prevent unauthorized operation of the truck, as shown in FIG. 3, a safety mechanism generally designated by the reference numeral 31 is provided for preventing unauthorized starting of the engine. The safety mechanism 31, may, for example, interrupt a fuel supply to the engine in a manner similar to, for example, Offenlegungsschrift No. 2, 300,258.
The safety mechanism 31 includes a solenoid valve 32 disposed in a fuel line 33 for controlling a supply of fuel from a fuel tank 34 to a fuel injection pump 35. The solenoid valve 32 is adapted to selectively block the fuel line 33 and, for this purpose, the solenoid valve 32 is connected to a power source 37 through an electrical circuit 36. The electrical circuit 36 includes a key operated switch 39 adapted to be closed with a key 38 inserted and opened when the key 38 is withdrawn or removed. The three-way valve 28, constructed as a solenoid valve, is connected to the power source 37 by a circuit means 40 branching off the circuit 36. The three-way valve 28 is operable to direct a flow of hydraulic fluid into the by-pass line 29 and the safety mechanism may be operated by the single key 38.
When the key 38 is inserted into the key operated switch 39, the circuit 36 is closed and the solenoid valve 39 opens the fuel line 33 so as to allow fuel to flow between the fuel tank 34 and the fuel injection pump 35 whereby the engine may be operated. At the same time, the three-way valve 28 is in the switch position d (FIG. 1) in which a tilting or lowering of the cab is possible.
When the key 38 is removed, as shown in FIG. 3, the circuit 36 is broken and the solenoid valve 39 closes or blocks the fuel line 33 so that no fuel can flow from the tank 34 to the injection pump 35 through the fuel line 33, thereby preventing the engine from operating. At the same time, the three-way valve 28 occupies the switch position e (FIG. 2) so that it is no longer possible to tilt the cab thereby denying access to the engine and/or other components under the cab. Thus, the construction of FIG. 3, provides a two-way assurance against an unauthorized starting of the engine of the truck.
While we have shown and described several embodiments in accordance with the present invention, it is
understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to one having ordinary skill in the art, and we therefore do not wish to be limited to the details shown and described herein, but intend to cover all such modifications as are encompassed by the scope of the appended claims.
货车驾驶室液压翻转机构(翻译附原文,仅供参考)
