Fig. 3134.
Four rates of feed are provided, and the upper wheel can be set at the required angle from a perpendicular while the machine is in motion.
The upper guide wheel, and the mechanism by which it is carried, is counterbalanced by a weight that hangs within the column or main frame, and is therefore out of sight.
Fig. 3135.
The construction of the parts by means of which the upper wheel is adjusted in height to regulate the tension of the saw, and which also cants the wheel out of the vertical, is shown in [Fig. 3135], which represents a portion of the main frame or column, on which is a slideway b, for the slide c, which carries the bearing for the upper wheel.
The method of moving the slide c for moving the upper wheel to adjust the saw tension is as follows:
By means of the handle h and the worm and worm wheel at w, the shaft s is revolved. The upper end of s is threaded into the nut n, which is capable of end motion in its bearing at e, and which abuts against the lever l, the latter abutting against the end of the screw m, and acting at its other end on the rubber cushion p. Now suppose that s be revolved in the direction denoted by the arrow, and the effect will be to raise the nut n. This effect will be transferred through the screw m to the slide c, which will rise up on b, carrying with it the upper wheel bearing and wheel.