D CHANGEABLE SPEED GEARING.

This is the invention of Lawrence Heath, of Macedon, N.Y., and relates
to that class of changeable speed gearing in which a center pinion
driven at a constant rate of speed drives directly and at different
rates of speed a series of pinions mounted in a surrounding revoluble
case or shell, so that by turning the shell one or another of the
secondary pinions may be brought into operative relation to the parts
to be driven therefrom.

The aim of my invention is to so modify this system of gearing that
the secondary pinions may receive a very slow motion in relation to
that of the primary driving shaft, whereby the gearing is the better
adapted for the driving of the fertilizer-distributers of grain drills
from the main axle, and for other special uses.

Fig. 1 is a side elevation. Fig. 2 is a vertical cross section.

[Illustration: FIG. 1.]

[Illustration: FIG. 2.]

A represents the main driving shaft or axle, driven constantly and at
a uniform speed, and B is the pinion-supporting case or shell, mounted
loosely on and revoluble around the axle, but held normally at rest by
means of a locking bolt, C, or other suitable locking device adapted
to enter notches, _c_, in the shell.

D is the primary driving pinion, fixed firmly to the axle and
constantly engaging the pinion, E, mounted on a stud in the shell. The
pinion, E, is formed integral with or firmly secured to the smaller
secondary pinion, F, which in turn constantly engages and drives the
center pinion, G, mounted to turn loosely on the axle within the
shell, so that it is turned in the same direction as the axle, but at
a slower speed.

F', F_{2}, F_{3}, F_{4}, etc., represent additional secondary pinions
grouped around the center pinion, mounted on studs in the shell, and
made of different diameters, so that they are driven by the center
pinion at different speeds. Each of the secondary pinions is formed
with a neck or journal, _f_, projected out through the side of the
shell, so that the external pinion, H, may be applied to any one of
the necks at will in order to communicate motion thence to the gear,
I, which occupies a fixed position, and from which the fertilizer or
other mechanism is driven.

In order to drive the gear, I, at one speed or another, as may be
demanded, it is only necessary to apply the pinion, H, to the neck of
that secondary pinion which is turning at the appropriate speed and
then turn the shell bod