LEATHER BELTING. An examination of the different leather departments, and the varieties of belting in actual use, reveal a tendency on the part of manufacturers to improve the quality of wide belts by securing 2-inch strips along their edges. Specimens of this character are exhibited by Messrs. Webb & Son, Stowmarket, England ; Mr. William Euland, of Bonn, Prussia ; H. Lemaistre & Co., Brussels, Belgium; Placide Pelter-eau, 32 Rue d'Hauteville, Paris; Poullain Brothers, 99 Rue de Flandre, Paris; and others of less note. The material forming these strips is (with a single exception) leather of the same quality as the belt. The methods of attachment are variable, as laces, threads, rivets, eyelets, and brass screws. The English use the threads, Prussians the laces, and the French all the varieties enumerated. Mr. P. Peltereau, pro-piietor of one of the largest houses in France, makes a remarkable display, not only of belts and their mountings, but of different kinds of leather ; such as tanned elephant hide, varying in thickness from one fourth to one half an inch, and hippopotamus hide, from one inch to one and a half inches in thiclsness. His 8-inch and 10-inch belts have leather facings two inches wide on their edges. Each of these facings is attached ]3y two leather laces, whose stitches have three fourths of an inch span, and run in parallel lines, separated by one and one fourth inch. The ''inextensible belt," for which, at a previous exposition, he received a gold medal, has steel instead of leather edging strips. These strips, for a 10-inch belt, are two inches wide by one sixty-fourth of an inch in thickness, and attached by two riveted rows of copper tacks. These tacks are one eighth of an inch in diameter, and placed three and one half inches between centers. Messrs. Poullain Br others join their single, and compound their double belts with headless one eighth of an inch brass screws. This is accomplished with a very ingenious machine, of which there are several types in the French department. It carries a coil of plain brass wire, which, while being fed to the work, passes through a die of twenty-eight threads to the inch. The screw thus formed enters the belt at a point closely clamped by a foot-lever, and, having passed through, is cut off*. Finally, the belt being placed on a surface plate, the points of all the screws are slightly riveted. The most compact and expeditious of these machines is the invention of Mr. Cabourg, 74 Rue St. Honore, Paris. Mr. E. Scellos, of 74 Boulevard du Prince Eugene, exhibits what he terms a " homogeneous belt," for 150-horse power. This belt is nineteen and one half inches wide by three fourths of an inch in thickness. It is composed of 104 leather strips three fourths of an inch in width, laid longitudinally with reference to the belt, and laced transversely; the distance between laces iB one and one fourth inch, and dia- meter of lace equals three sixteenths of an inch. The advantage of edge-bound wide belts, where frequent shipping is an essential, we think will be readily conceded ; and to what extent they can supplant double belts, is a subject worthy of experimental inquiry. The use of very wide belts is seldom resorted to in the machinery department. One of the stationaries has two central ribbed pulley rims bolted to the arms of its fly wheel; on these run four belts six inches in width ; another has two 12-inch edged belts, and so on— the inclination was always to increase the number rather than the width of the belts. TRANSMISSIO]S- OF POWER TO GREAT DISTANCES. For the transmission of power to great distances, leather and rubber belts are rendered useless by their extreme elasticity, and the expensive character of their intermediate supports ; while shafting with bevel gears consumes the applied power in excessive friction, elasticity, etc. These difficulties ' were studiously met and successfully solved by Mr. C. F. Hirn, of Colmar, Haut Rhin, in the year 1860 ; the practical | working of his invention was partially displayed at the exhibition of 1862. In the park of the present Exposition, his system is clearly shown by the operation of a centrifugal pump, deriving its power from a stationary engine, working on the opposite side of the artificial lake, and distant some 500 ft. from the pump. This so-called " telody-namic system is based on the substitution of a high velocity devel oped in a small mass, for its converse; namely, large mass moving with small velocity. The power conductor is simply a light wire rope, passing over pulleys of large diameter, and upheld at intervals of about four hundred feet by support-pulleys. The construction of these pulleys, and their supports, is shown by the accompanying figures, 1 and 2, giving a side view and end view, and a section of the rim of the pulley. The two extreme pulleys, or those which receive and distribute the power, are rotated at speeds having a circumferential velocity of 1,800 to 4,800 feet per minute. It has been the practice to make these of cast iron, but steel is recommended where higher velocities are necessary. The face of the pulley is channeled by a deep Y-groove, while the bottom of the latter has a filling of gutta-percha which adapts itself more and more perfectly to the rope and entirely prevents elip and wear. Fig. 2 is a section of the rim of tlie support pulley, showing the cable A, resting upon the gutta-percha cuishion, B. Herein lies the secret of its practical success ; a result only attained after most discouraging experiments upon pulleys constructed successively of copper, wood, cast iron, etc., with facings of leather, india-rubber, horn, lignumvitse, and boxwood. Experience has proved that the loss of power by the telo-dynamic system is quite trifling, and arises mainly from the resistance of the air to the arms of the pulleys, the friction of their axles, as well as the rigidity of the rope in its passage over the pulleys. It has been found that two pulleys, twelve feet in diameter, making 100 revolutions per minute, with a cable of seven sixteenths of an inch diameter, can, by means of a circumfer-ertial velocity of 4,000 feet per minute, transmit 120-horse power (to distances less than 400 feet) without sustaining a loss of more than two and one half per cent. If this limit is exceeded, it will become necessary to introduce support pulleys of seven feet diameter, and for these there should be estimated a mechanical Joss of about one per cent per 8,300 feet of distance traveled. The pecuniary expense, independent of the ground rent, amounted to $1,000 (gold) per 8,300 feet, plus $600 for the receiving and distributing pulleys, with tlieir respective shafts and supports. It v eyidciat that this system cannot b e limited i n its application by rectilinear transmission, but is susceptible of all the changes in direction which inclined pulleys can command. There are already between 400 and 500 instances of its employment in connection with the manufacturing interests of the continent. Its advantages in respect to our own country can hardly be overestimated.
This article was originally published with the title "Transmission of Power" in Scientific American 21, 12, 181 (September 1869)