The Mechanical Handling and Storing of Material

7i8 THE MECHANICAL HANDLING OE MATERIAL Fig. 1031. Dashpot. into a bath of mercury, and loaded sufficiently to cause it to be submerged some distance in the mercury before the machine is in balance unloaded. It will be seen that when the heavier load comes on the machine the lever rises, and the greater portion of the piston comes out of the mercury until the balance is again established. At the same time a small hole in the hollow piston allows the mercury to escape comparatively slowly. This arrange- ment acts as a dashpot for steadying the oscillations of the lever when the latter takes up a particular position due to the weight of the length of conveyor and the load on it. The registering mechanism is shown in Fig. 1032. The cam a causes the levers e to move to the right, and this thrusts the steelyard f of the weighing machine against a surface so roughened as to prevent it from slipping. Another cam then permits the registering quadrant (which is moved to the right by a system of levers actuated by gravity) to move freely to the right, a movement which is only checked by the clamped steelyard f. As the quadrant moves to the right the ten pawls ride over the teeth of the registering wheel. There is a brake on the registering wheel which acts immediately the quadrant is at its left-hand limit. This is to prevent the momentum of the wheel from' carrying it on. The cam G causes the quadrant invariably to move back to the same left-hand - limit, the pawls engaging and carrying the registering wheel with the quadrant. It is therefore evident that the rotation of the registering wheel is dependent upon the extent of the movement of the quadrant to the right. This is determined by the position of the weighing lever, and this again by the weight on the machine. The two