The Story of the "Independence" Wood Split Pulley.
More than a quarter century ago Wallace H. Dodge founded at Mishawaka, Ind., what has since become known as the Dodge Manufacturing Co. The embryo was in the form of a little saw mill for the production of hardwood lumber, and it is of interest to note that never from that time to the present has the saw mill feature been missing from the company‘s plant. Today, of course, it is merely one minor item of the large manufacturing system.
Production of window screens, door stops, tool handles, saw frames, bench clamps, vise handles, mallets, etc., followed as a natural extension of the business, requiring the addition of a turning lathe and other simple tools. This little industry prospered so well that in 1880 the Dodge Manufacturing Co. was incorporated by Wallace H. Dodge, William W. Dodge and George Phllion. The business continued to grow rapidly and steadily, with every indication of gratifying prosperity. Within a year, however, in 1881, the factory was destroyed by fire.
The loss of its uninsured plant was a serious one for the young concern, but rebuilding was undertaken at once. In the rise of the factory there appeared that necessity which, again the mother of an invention, gave birth to the practial wood split pulley, so closely identified with the name of Dodge. With comparatively small capital for building and equipment purposes, economy at every possible point was necessary. Fortunately, the lack of funds was offset at many points by an abundance of resourcefulness and genius for meeting difficulties, and the problem of fitting out the new lineshafting was solved by the construction of satisfactory pulleys of wood, crude but quite serviceable.
While this was not the first instance of the use of wood in pulley construction, yet the Dodge Manufacturing Co. is credited with having first recognized the considerable value and great possibilities of the wood pulley idea, and with having developed the idea into practical commercial form. Extensive experimenting and successive improvement finally led to the Dodge "Independence" wood split pulley, with standardized hub bores and interchangeable bushings. The several steps in advance from the first commercially practicable wood pulley to-the perfected and standardized "Independence" type, were protected by Dodge patents.
Such an innovation as the idea of substituting wood for iron in the construction of that hard-worked item of mechanical equipment, the belt pulley, was enough in itself to cast doubt upon the seriousness of the proposition. Naturally, then, the very sanity of the inventor was questioned when he urged that the key and setscrew be eliminated and that dependence for driving connection between shaft and pulley hub be placed in the simple friction of wood clamped onto iron. The facts, early and easily demonstrated, that the Dodge "Independence" wood split pulley, besides offering better tractive surface for the belting, was actually stronger and lighter, as well as in all ways more convenient than the ordinary iron pulley, and that the clamp fastening was ample and positive, and led to the recognition and adoption by power users generally.
As an example of its wide range, pulleys 24 to 48-in. diameter, with 3½-in. bores, can, by means of separable wood bushings, be used on shafts ranging from 1 to 3½-in. diameter, other sizes having a proportionate range. Four to twelve hub bolts, according to size, and two rim bolts, produce a fastening, by compression alone, as secure as if the pulley were solid and keyed to shaft. Rim and hub bolts, when pulled up, bring the two halves of the rim in contact at exactly the same time that full bearing is secured on the shaft through hub or bushing; this makes the rim pressure and shaft pressure identical, a feature so essential to a perfect running pulley. Every pulley is balanced and inspected before it leaves the factory.
The efficiency of the Dodge wood and iron split pulleys is due, perhaps, quite as much to their bushing systems as to their mechanical construction. Without bushings these pulleys could be used for but one size of shaft, and would be different from solid pulleys only in the fact that they were split.
Twenty-seven years ago two "Independence" wood split pulleys were placed in service at a saw mill in northern Indiana. Recently these pulleys were taken down for examination and found to be in perfect condition, round and true, every glue joint tight, and the face polished like a piano. These pulleys were among the first put to use following the granting of patents to the late Wallace H. Dodge and George Phillion, and have been in almost continuous operation all the time. One measures 48x16 and the other 24x9.