Shaft to another so as to Increase the Speed.
Year: 1885

page_text: Shaft to another so as to Increase the Speed.
I, EDWARD WILSON, of Commercial Road, Exeter, in the County of Devon,
Engineer, do hereby declare the nature of my invention for "IMPROVED MEANS
FOR TRANSMITTING ROTARY MOTION FROM ONE SHAFT TO ANOTHER, SO AS TO
INCREASE THE SPEED," to be as follows:-
The object of my invention is to enable motion to be transmitted from one shaft
to another in different planes, so that the speed may be increased. It consists in
the use of a worm wheel on the shaft from which motion is to be transmitted, and
a worm on the shaft to be driven by it, the speed being regulated by the diameter
of the wheel and the pitch of the teeth. In order to enable this to be practically
carried into effect I cause both the worm and wheel to revolve in a casing or box
partly filled with any suitable lubricant, so that the contact surfaces will always
be continuously lubricated, thereby preventing the great friction and consequent
wear and tear which would otherwise occur.
I further prefer to give a special form to the teeth of the worm wheel and the
thread of the worm, for the purpose of causing the weight of the revolving parts to
be borne principally by such parts themselves, so as to reduce the friction upon the
bearings of the worm. For this purpose I make the periphery of the worm an arc
of a circle of the same radius as the worm wheel, and shape the contact surfaces of
the teeth of the latter and the thread of the former, radial (or practically radial)
with the centre of the worm wheel, by which means such contact surfaces are
materially increased: Or instead of being radial the contact surface of the teeth
on the wheel might be inclined forward in the direction of rotation, and the contact
surface of the thread on the worm be correspondingly formed.
It will thus be seen that I overcome the principal difficulties of driving the worm
at high speeds.

page_text: improved means for Transmitting Kotary motion from one
Shaft to another so as to Increase the Speed.
I, EDWARD WILSON, of Commercial Road, Exeter, in the County of Devon,
Engineer, do hereby declare the nature of this invention, and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
The object of my invention is to enable motion to be transmitted from one shaft
to another in different planes, so that the speed may be increased. It consists in
the use of a worm wheel on the shaft from which motion is to be transmitted, and
a worm on the shaft to be driven by it, the speed being regulated by the diameter
of the wheel and the pitch of the teeth. In order to enable this to bo practically
carried into effect I cause both the worm and wheel to revolve in a casing or box
partly filled with any suitable lubricant, so that the contact surfaces will always
be continuously lubricated, thereby preventing the great friction and consequent
wear and tear which would otherwise occur.
I further prefer to give a special form to the teeth of the worm wheel and the
thread of the worm, for the purpose of causing the weight of the revolving parts to
be borne principally by such parts themselves, so as to reduce the friction upon the
bearings of the worm, and also for the purpose of giving as large a contact surface
as possible between the teeth of the wheel and thread of the worm. For this
purpose I make the periphery of the worm an arc of a circle of the same radius as
the worm wheel, and shape the contact surfaces of the teeth of the latter and the
thread of the former, radial (or practically radial) with the centre of the worm
wheel, by which means such contact surfaces are materially increased. Or instead
of being radial the contact surface of the teeth on the wheel might be inclined
forward in the direction of rotation, and the contact surface of the thread on the
worm be correspondingly formed.
It will thus be seen that I overcome the principal difficulties of driving the worm
at high speeds.
My invention is illustrated in the accompanying drawings, in which Fig. 1 is an
end elevation partly in section, and Fig. 2 a longitudinal section of my improved
arrangement.
A is the worm wheel mounted on the shaft B to which motion is transmitted
by means of a strap and pulley as shown, or by any other suitable means. The
wheel A gears with the worm C mounted on shaft D, which is thus driven at a
greater speed than shaft B, the increase in speed depending on the diameter of
wheel A and the pitch of the teeth. A box or casing E encloses both the wheel A
and worm C, and such box or casing is partly filled with any suitable lubricant in
which the wheel A revolves, so as to ensure the efficient continuous lubrication of
the contact surfaces. I may place a fixed guide close to the periphery of the worm
wheel up to the worm, for the purpose of guiding the lubricant into the latter.
The special form of the teeth of the worm wheel and the thread of the worm,
and also the means employed for ensuring efficient lubrication of the contact
surfaces, above described, may also be employed when the worm is used as the
driver and the worm wheel mounted on the shaft to be driven.

page_text: Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. The improved means for increasing speed by fitting a driving shaft with a
worm wheel gearing with a worm carried by the shaft to be driven, substantially
as described.
2. Reducing the friction on the bearings of a shaft carrying a worm gearing
with a worm wheel, and increasing the contact surfaces between such worm and
wheel, by making the periphery of the thread of the worm an arc of a circle of the
same radius as the wheel and suitably shaping their contact surfaces, substantially
as described.
3. Enclosing the worm and worm wheel in a casing or box partly filled with
any suitable lubricant, for the purpose of ensuring efficient continuous lubrication,
substantially as specified.