Machines

The hydraulic press

The hydraulic press When a fluid completely fills a vessel, and a pressure is applied to it at any part of the surface, that pressure is transmitted equally throughout the whole of the enclosed fluid. This is known as Pascal’s.principle (see also page 122). This principle finds an important industrial application in the hydraulic press (Fig. 8.16). This …

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The screw

The screw Millions of screws and bolts are used daily for the purpose of holding things together. We have already mentioned the importance of the screw in connection with micrometers (page 7). In addition, the screw is an essential feature of machines such as vices and screw jacks (Fig. 8.11, 8.12). The distance between successive threads on a screw …

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The inclined plane

The inclined plane A heavy load may be raised more easily by pulling it along a sloping surface than by lifting it vertically. Heavy packing cases are often loaded into vans by hauling them up an incline formed by two stout planks held apart by iron stays (Fig. 8.9). It is believed that the large blocks of stone used …

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To study the variation of the mechanical advantage of a pulley system with load

To study the variation of the mechanical advantage of a pulley system with load We shall use a block and tackle with two pulleys in each block for this experiment, but the same principle may equally well be applied to other types of machine. The pulleys are set up as in Fig. 8.7, scale-pans being provided for the …

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The block and tackle

The block and tackle This is by far the most important pulley system of all, being commonly used for lifts and cranes. Two blocks are employed containing from two to eight pulleys in each, according to the mechanical advantage required. To illustrate the principle, Fig. 8.6 has been drawn to show two pulleys in each block. For simplicity, the …

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