West's Moulders' Text-book: Being Pt. II of American Foundry Practice ...

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J. Wiley & Sons, 1901 - 518 páginas
 

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Página 14 - ... care and operation of the plant. Just as a chain is no stronger than its weakest link so is the water plant or sewage plant no safer than the staff of its operators. Proper supervision may prevent disastrous results and in this supervision the engineer constantly needs the laboratory worker associated with him at his elbow.
Página 444 - Experience has demonstrated that the wear increases with the speed. It is, therefore, better to increase the load than the speed. Wire rope is manufactured either with a wire or a hemp center. The latter is more pliable than the former, and will wear better where there is short bending. Wire rope must not be coiled or uncoiled like hemp rope. When mounted on a reel, the latter should be mounted on a spindle or flat turn table to pay off the rope.
Página 444 - ... in that way. All untwisting or kinking must be avoided. To preserve wire rope, apply raw linseed oil with a piece of sheep-skin, wool inside, or mix the oil with equal parts of Spanish brown or lamp-black. To preserve wire rope under water or under ground, take mineral or vegetable tar, and add one bushel of fresh-slacked Erne to one barrel of tar, which will neutralize the acid.
Página 443 - Several kinds of wire rope are manufactured. The most pliable variety contains nineteen wires in the strand, and is generally used for hoisting and running rope. The ropes with...
Página 444 - For safe working-load, allow one-fifth to one-seventh of the ultimate strength, according to speed, so as to get good wear from the rope. When substituting wire rope for hemp rope, it is good economy to allow for the former the same weight per foot which experience has approved for the latter. " Wire rope is as pliable as new hemp rope of the same strength : the former will therefore run over the same size sheaves and pulleys as the latter.
Página 446 - Fixed and the other projecting, the strength is inversely as the distance of the weight from the section acted upon ; and the strain upon any section is directly as the distance of the weight from that section.
Página 470 - Proportion to the breadth, and as the Square of the Depth.'* "Hence may be inferred, that the strength of the teeth of wheels, moving at the same velocity, and under the same circumstances, is directly in proportion to their breadth, and as the square of their thickness. Thus, for example, if we double the breadth, we only double the strength ; but if we double the thickness, or, in other words, double the pitch, keeping the original breadth, we increase the strength four times. " For although when...
Página 480 - Experiment has shown that hooks made according to the above formulae will give way first by opening of the jaw, which, however, will not occur except with a load much in excess of the nominal capacity of the hook. This yielding of the hook when overloaded becomes a source of safety, as it constitutes a signal of danger which cannot easily be overlooked, and which must proceed to a considerable length before rupture will occur and the load be dropped.
Página 132 - It is very widely diffused, occurs in great abundance in many parts of the world, and is found in rocks and strata geologically very different, as in transition rocks, in secondary and in tertiary formations. It often occurs...
Página 470 - A WHEEL. Rule. — Multiply the number of teeth by the pitch, and divide the product by 3. 1416. Example. — The number of teeth in awheel is 75, and the pitch 1.675 in.

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