Elevators; A Practical Treatise on the Development and Design of Hand, Belt, Steam, Hydraulic, and Electric Elevators

Elevators; A Practical Treatise on the Development and Design of Hand, Belt, Steam, Hydraulic, and Electric Elevators

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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. 1916 edition. Excerpt: ...Armstrong had made a three-cylinder machine, the piston of each cylinder being attached to the same crosshead. For light loads he admitted water to one cylinder only--the central one; for medium loads to the two outside cylinders only; and for heavy loads to all three. The result was no marked success, the valve motion being too complicated, and the friction of the three pistons detracting greatly from the efficiency of the machine. Fensom Balancing Device. John Fensom of Toronto, Canada, had developed the scheme of using a circulating pipe connecting the front and back ends of a horizontal machine in such a way that the water, after being used for hoisting, was discharged on the lowering trip into the other end of the cylinder, and then on the next up-trip was forced into overhead tanks for use about the building. To take care of the heavy loads, he set the bearing boxes of his overhead sheave on the end of a lever pivoted on knife-edges similar to those used with the levers of large platform scales. The long end of this lever was weighted to suit the loads as shown in Fig. 72. When a heavy load was placed on the car or platform of the elevator, it would lift the long end of the lever, having overbalanced it and the weight attached. The long end of this lever had connected to it a small cable or a thin rod running down to a pipe laid underground and connected to the sewer. This rod or cable was attached to a valve set in the pipe and when, through an overweight on the platform, the lever was raised, it opened the valve in the pipe and allowed the discharge water to run to waste, thus relieving the piston of back pressure and allowing the elevator to lift the heavy load. Hence it was only while lifting light and medium loads that water was...show more

Product details

  • Paperback | 54 pages
  • 189 x 246 x 3mm | 113g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236584538
  • 9781236584533