Variation in height may be obtained by moving the planes and the balance weight.
C C is the bed plate and D the balance weight, F the rod leading to quadrant and lever on foot plate.
A balance weight w, Fig. 907, is necessary to counterbalance the weight of the angle plate.
This beam is braced with iron, and has segmental ends with a piston at one end, and a balance weight at the other.
The forks between which the belt runs are also provided with a balance weight.
This arm striking against the ratchet detent releases the balance weight, and the belt is at once brought on to the loose pulley.