Читать книгу The Modern Bicycle and Its Accessories - Julius Wilcox - Страница 44

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The Pine chainless, located at 23 Duane street, is a model still behind, so that we have not been able to see a finished sample or even any working part. The general appearance is that of the Sager gear, the shaft being tubular and revolving outside the stay as in that type. The gears are claimed to be really spur gears with teeth cut square; that is, essentially so, for there must be some slight modification, as it is not as if two ordinary spur gears were placed at right angles and made to mesh in that position. The teeth, however, are said to be square-cut, not radial; their sides are parallel, hence not pointing to the centre; the teeth are cut in a sort of trough, leaving a margin or hollow at their ends. The inventor terms his gear a “face” gear, and makes for it a number of claims, one of which is that he can and will convert any chain wheel into a Pine chainless at a cost of about $20. He likens his gear, in working, to the familiar breast drill, except that the drill has its teeth somewhat bevelled. If simplicity coupled with great strength and rigidity of frame, together with cheap construction and smooth and quiet action, are attained by this gear, as expected, it will evidently score a point among chainless models; but that straight-cut teeth can interact successfully at all with gears set at right angles or nearly so is contrary to all ideas heretofore, and in the lack of a model for examination we must forbear any opinion. The inventor’s own description is appended in justice to him:

PINE “SQUARE-TOOTH” CHAINLESS.

“This invention relates to driving or propelling mechanism applicable to various machines or vehicles, but intended particularly for bicycles. It comprises mainly a sprocket wheel carried by the crank shaft with straight teeth on the inner face on a raised edge, so cut upon a new principle and arranged to mesh with a spur or pinion fixed at one end of a tube, which revolves on ball bearings arranged on rear-fork sides or rod with another gear or sprocket, the opposite end of said tube having also a spur or pinion meshing with another sprocket secured to rear hub cut in a similar manner as front sprocket. The driving power being transmitted from front sprocket or gear by shaft tube to rear gear or sprocket, all being suitably secured as above stated to frame upon rear fork rotatably supported by ball bearings connected to the frame and forks.

“This does precisely what has always been accounted to be out of the question and confutes both theoretical and practical mechanics. It is a gear that turns the corner by means of square cut teeth that mesh directly instead of by means of bevel teeth, and we call it a face gear. It has generally been the accepted rule that in order to transmit power from one shaft to another running at right angles by means of cogs the cogs must be V-shaped and cut on a bevel plane. Spur gears have hitherto been used only for engagements between wheels turning in a direct line with each other; our new chainless looks much like a bevel-gear wheel at first glance, but a closer inspection shows that the teeth on the inside of front sprocket or pinion wheel as well as those on the driving shaft are perfectly square and mesh together as spur gears.”