| 摘要 |
In a radial arm saw, there is provided a continuously adjustable restraining device for controlling the speed of cut of the saw through work pieces positioned on the work table. The adjustable device has a hydraulic cylinder which is connected at one port to a first connection line, and at the other port to a second connection line. Each connection line is connected in turn to a valve which controls the flow of fluid from one connection line to the other. The valve has a pivotal lever for continuously adjusting the flow rate of fluid therethrough, which fluid is forced out of one port of the cylinder upon movement of the saw by the user of the saw, through the valve, and into the other port of the cylinder at a control rate determined by the pivotal rotation of the pivotal lever. Thus, the rate of flow of the fluid between the cylinder ports is variable and controllable, to thereby provide a desired counter-force to the movement of the saw as its progresses through its cut of the work piece. The hand saw is connected to the piston rod of the cylinder at a remote end of the piston rod. Thus, the thrust of the power hand saw toward the user during cutting can be controlled, and stalling of the motor of the saw can be obviated by slowing down the speed of cut. In the preferred embodiment, the valve is mounted on the handle of saw motor, for controlling the speed of cut with the same hand that is moving the saw.
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