This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1881 Excerpt: ...connecting-rod it sets in motion a single bob, the two ends of which carry rods connected with those of the. man-engine. Where this arrangement is adopted the size of the bob is limited by the dimensions of the pit, and consequently the stroke is too short and the rods are too far apart It is better to have two bobs ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1881 Excerpt: ...connecting-rod it sets in motion a single bob, the two ends of which carry rods connected with those of the. man-engine. Where this arrangement is adopted the size of the bob is limited by the dimensions of the pit, and consequently the stroke is too short and the rods are too far apart It is better to have two bobs joined by a connecting-rod, one on each side of the shaft, and in this manner the length of stroke can be determined at pleasure. (Fig. 385.) Instead of the two bobs we may adopt the more complicated arrangement of an hydraulic balance, which also permits the length of stroke being adjusted as thought desirable. The motor, whether steam or water, is made to work a piston in a cylinder full of water, the two extremities of which communicate freely with two twin vertical cylinders placed over the shaft. These cylinders are furnished with pistons, to which the man-engine rods are connected, and the whole arrangement works like the water-pressure engine described in No. 278, Cours de Machines, save that the varying speed is regulated by the motion of a crank instead of by valves. The length of stroke of the man-engine as compared with that of the force-pump ia in the inverse ratio of the sections of the cylinders. It should be borne in mind, that whatever plan may be adopted for working the rods, they are arranged exactly like pump-rods with regard to joints, guides, catches, changes of inclination, &c., all of which will be described later on. A man-engine rod differs in no respect from the main rod of pumps, save that it is usually smaller. (491) Attempts have been made in two ways to increase the carrying capacity of man-engines. In the first place, the stroke has been lengthened, and the average speed increased, without causing any injurious...
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