The Mechanical Engineer's Reference Book for Machine and Boiler Construction; In Two Parts

The Mechanical Engineer's Reference Book for Machine and Boiler Construction; In Two Parts

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1891 edition. Excerpt: ...VELOCITY or rui.1.i1Y RIM in feet per minute. X ' EXA1_fI'LE.--It is required to transmit 25 IHP. through a belt or a. pulley five feet diameter, making 120 revolutions per minute; what would be the tension on the tight side, assuming 1e coefficient to be '3 and the arc embraced 180? The circumference of 5 being 15-7, the velocity in feet per minute = 15'7 X 120 = 1,884 feet, and looking in the table opposite 180 and under '3. We find 1'64 501' 531111 lidfii 25 X 33.000 1.884 TRAKSNIISSIQN CF P0wER--contz'r11ted LEATHER BELTS, STRENGTH AND PERMISSIBLE TENSIONS.-3 MAY an ADOPTED as COEFFICIENT or FRICTION son ORDINARY PULLEYS; incipient slipping often goes on without being noticed. The strength of ordinary leather usually varies from 3,000 to 5,000 pounds per square inch; at a laced joint the strength is reduced to about '3 of this, and at a riveted joint to about '5. Taking 4,000 pounds per square inch as the ultimate resistance, we get the following: N.B.--The diameter of smallest pulley should not be less than 2o or 30 times the thickness of the belt. when the latter is single; if the belt is double the pulley should be So or ioo times the thickness. Instead of resorting to double belts, it seems preferable to run two single belts, one on top of the other; they are not only more eflective but can be run on smaller pulleys than would be required for double belting; the two single belts should be in no way fastened together. The flesh side of the leather should go next the pulley, it is the natural way for bending the leather; possibly more adhesion might be got the other way, but at the sacrifice of shortening the life of the belt. Belts should be as straight as a line, and the joints, as far as possible, the same more

Product details

  • Paperback | 100 pages
  • 189 x 246 x 5mm | 195g
  • United States
  • English
  • black & white illustrations
  • 1236902726
  • 9781236902726