Improvements in Worm Gear.
Year: 1892

page_text: Date of Application, 15th Nov., 1892-Accepted, 17th Dec., 1892
Improvements in Worm Gear.
I, JAMES. FRANKLIN WELCH, of No. 28 to 30 Clay Street, Brooklyn in the
County of Kings and State of New York, United States of America, Manager,
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:-
My invention relates to improvements in worm gear, with the object in view of
obtaining an increased area of contact between the teeth of the worm and gear
wheel.
A practical embodiment of my invention is represented in the accompanying-
drawings, in which
Fig. 1 is a view of the worm in side elevation, shewing in dotted lines a section
of the worm wheel in engagement therewith.
Fig. 2 is a view of the worm wheel in side elevation; and
Fig. 3 is a view of the worm wheel in edge or face elevation.
The outer faces of the teeth on the worin, taken in a plane extending through
the longitudinal axis of the worm, are in the circumference of a circle corresponding-
to the circumference of the worm wheel at the base of the teeth, in a central plane
transversely to its axis; and the faces of the teeth on the worm wheel are formed
on a wind corresponding to the wind of the worm, and are concave on a curve-
corresponding to the curve of the worm shaft between its teeth, while the bottoms
of the spaces between the teeth on the worm wheel, are concave on a curve corre-
sponding to a curve of the faces of the teeth on the worm.
The contact sides of the teeth on the worm continuously change their positions.
relatively to the axis of the worm shaft, throughout their length, to conform to the
continuously changing positions of the teeth on the worm wheel, and the contact
sides of the teeth on the worm wheel have a wind or compound curve corresponding-
to the sides of the teeth on the worm, having a general oblique direction across the
face of the worm wheel.
The worm shaft is represented by A, and is shown, in the present instance, as
provided with two teeth, a and a¹.
The worm wheel is represented by B, and its teeth by b.
As the worm wheel is caused to rotate by the action of the worm, its tooth, with
which the worm engages gradually, changes its position relatively to the axis of
the worm shaft, and my present invention provides for such a structure of the
worm tooth, that its contact side, a³, for example, will adjust itself to such
constantly varying positions of the tooth on the worm wheel, and thereby exert a
constant pressure upon such tooth, during its travel through a considerable portion
of its arc.
The teeth b on the worm wheel have a shape which conforms to the space between:
two successive teeth of the worm, leaving a little space for clearance.
Having now particularly described and ascertained the nature of my said inven--
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:―
A worm and a worm wheel, a tooth of the worm being set in a curved plane.
corresponding to the curve of the circumference of the worm wheel, and having its
driving or contact side varied along its length, to assume different pitches relative
to the axis of the worm, and the teeth on the worm wheel having their contact

page_text: sides formed in a compound curved plane having a general oblique direction across
the face of the wheel, to correspond to the face of the worm tooth, substantially as
set forth.
T
7.1+
.
יה
1800
NEWTON & SON,
Agents for the Applicant.