| 摘要 |
<p>A bow saw machine has a machine frame; a device for immobilizing a workpiece in the machine; a housing pivotally attached to the machine frame for providing for a swinging motion of the housing generally in a vertical plane; a saw bow supporting a saw blade in a generally horizontal orientation during the sawing operation; a guide supported in the housing for longitudinally displaceably mounting the saw bow; a drive motor; a crank drive supported in the housing and having a generally vertically oriented drive shaft eccentrically coupled to the saw bow for effecting a reciprocating motion thereof along a path of reciprocation determined by the saw bow guide. The crank drive is located above the saw bow substantially within the zone of its path of reciprocation. The bow saw machine further has a hydraulic cylinder-and-piston assembly for controlling the sawing pressure and the feed of the saw blade; a bell crank having first and second arms extending from its pivotal support and being arranged at an angle to one another. The first arm is pivotally connected to the cylinder-and-piston assembly, while the second arm is coupled to a horizontal push rod reciprocated horizontally by virtue of its eccentric connection to the shaft of the crank drive. This arrangement provides that the saw blade is lifted off the workpiece during each idle stroke of the saw bow and is lowered into a sawing position for the beginning of each work stroke.</p> |
