Improvements in the Outting of Worm Gearing.
Year: 1894

page_text: Date of Application, 23rd Feb., 1894
Complete Specification Left, 23rd Nov., 1894-Accepted, 29th Dec., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Outting of Worm Gearing.
I JOSEPH STANDRING DRONSFIELD of the Firm of Dronsfield Brothers
Limited, of the Atlas Works, Oldham, in the County of Lancaster, Card Grinding
Machine Makers, do hereby declare the nature of this invention to be as follows:-
My invention relates to the cutting of worm wheels and whilst being especially
applicable in the cutting of wheels which are intended to gear with one another
may also be used in the cutting of ordinary so termed worm wheels.
employ a revolving cutter which is turned or formed to resemble a portion of
a screw and to correspond with and represent the wheel pinion or worm which it is
intended shall gear with the wheel or pinion to be cut. This cutter is finished in
the ordinary manner as when preparing milling cutters for use or is finished and
prepared in a suitable manner and is mounted upon a shaft or is mounted to be
revolved. The blank to be cut is also fixed upon a shaft or is mounted to be
revolved and the two shafts are connected by means of gearing proportioned to
impart the correct required speed to the blank being cut relative to the speed
of the cutter and of the worm or wheel which is to gear with the wheel being
cut, as for example if the intended gearing is to consist of a pinion revolving twice
for one revolution of the driven wheel and if the cutter represents such pinion
then the two shafts must be connected by gearing proportioned to cause the blank
The cutter and the blank
being cut to revolve at half the speed of the cutter.
will thus revolve at the same relative speeds as the intended worm gearing. As the
two shafts to be connected revolve on axes at right angles with one another it is
necessary to employ either bevel wheels or a worm and wheel or helical wheels to
constitute parts of the connecting gearing. The cutter is set in to the blank so as
to cut the spaces or screw grooves upon the blank or the blank is set up or toward
the cutter as the cutting proceeds.
In practice I mount the shaft carrying the blank upon a sliding carriage which
can be set up by means of a screw. When a number of duplicate wheels have to
be cut I find it convenient to prepare a wheel to represent the wheel to be cut.
This wheel is fixed upon the shaft which carries the blank and is driven by means
of a worm or of a helical wheel which is prepared to represent the cutter and is
fixed upon a shaft which is mounted to revolve in bearings upon the carriage.
The last named shaft is connected with the cutter shaft by means of an intermediate
wheel gearing with wheels fixed upon the two shafts. To provide for the setting
up of the work I carry the said intermediate wheel upon jointed links or frames
which are mounted to turn upon the axes of the two shafts and are hinged together
the centre of the hinge coinciding with the axis of the intermediate wheel.
I do not confine myself to the precise method of connecting the two shafts so
long as they are positively actuated at the correct relative speeds.
It is not necessary that the wheel fixed upon the shaft which carries the blank
and the driver wheel or pinion shall be of the same proportions as the cutter aud
the wheel to be cut so long as the connecting gearing is proportioned to impart the
proper relative speed to the blank.
Dated this 22nd day of February 1894.

page_text: Improvements in the Cutting of Worm Gearing.
I JOSEPH STANDRING DRONSFIELD of the Firm of Dronsfield Brothers
Limited, of the Atlas Works, Oldham, in the County of Lancaster, Card Grinding
Machine Makers, 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 and accompanying drawings
―:
My invention relates to the cutting of worm wheels and whilst being especially
applicable in the cutting of wheels which are intended to gear with one another,
may also be used in the cutting of ordinary so termed worm wheels.
I employ a revolving cutter which is turned or formed to resemble a portion of a
screw and to correspond with and represent the wheel pinion or worm which it is
intended shall gear with the wheel or pinion to be cut. This cutter is finished in
the ordinary manner as when preparing milling cutters for use, or is finished and
prepared in a suitable manner and is mounted upon a shaft or is mounted to be
revolved.
The blank to be cut is also fixed upon a shaft or is mounted to be revolved and
the two shafts are connected by means of gearing proportioned to impart the
correct required speed to the blank being cut, relative to the speed of the cutter
and of the worm or wheel which is to gear with the wheel being cut. For
example if the intended gearing is to consist of a pinion revolving twice for one
revolution of the driven wheel and if the cutter represents such pinion, then the
two shafts must be connected by gearing proportioned to cause the blank being
cut to revolve at half the speed of the cutter. The cutter and the blank will
thus revolve at the same relative speeds as the intended worm gearing. As the
two shafts to be connected revolve on axes at right angles with one another, it is
necessary to employ either bevel wheels or a worm and wheel or helical wheels to
constitute parts of the connecting gearing. The cutter is set in to the blank so
as to cut the spaces or screw grooves upon the blank or the blank is set up or
toward the cutter as the cutting proceeds.
· The accompanying sheet of drawings illustrates sufficiently clearly the subject
matter of my invention.
Fig. 1 is a side elevation of a suitable apparatus.
Fig. 2,is a plan.
I mount the shaft or stud a carrying the blank 6 upon a sliding carriage c which
can be set up by means of a screw, not appearing in the drawings, so as to feed
the blank b against the spiral cutter x which is formed exactly of the curve, pitch
and shape of the worin intended to drive the worm wheel to be formed from the
blank b. When a number of duplicate wheels have to be cut, I find it convenient
to prepare a wheel d to represent the wheel to be cut. This wheel d is fixed upon
the shaft a which carries the blank b and is driven by means of a worm e or of a
helical wheel fixed upon a shaft which is mounted to revolve in bearings upou
the carriage c. The last named shaft is connected with the cutter shaft g by
means of intermediate wheels h, i gearing with the wheels j, k fixed upon the two
shafts and g. To provide for setting up and withdrawing the work towards and
away from the cutter, carry the said intermediate wheels hi upon jointed links
or levers l, m, n which are mounted to turn upon the axes of the two shafts f and g
and are hinged together, the centres of the hinges coinciding with the axes of the
intermediate wheels as clearly shown in the drawing.
I do not confine myself to the precise method of connecting the two shafts f, g
so long as they are positively actuated at the correct relative speeds.
The result of the arrangement illustrated in the drawings is that the blank b is
moved at the exact speed relative to the speed and pitch of the worm outter

page_text: which will cause and allow the blank b to be cut with teeth which will exactly fit
both in curve and pitch, the worm with which it is intended to engage and which
worm will correspond exactly to the thread, pitch and proportions of the spiral or
worm cutter ..
It is not necessary that the wheel d fixed upon the shaft a which carries the
blank, and the driver wheel or pinion e should be of the same proportions as the
cutter and the wheel to be cut from the blank, so long as the connecting gearing
is proportioned to impart the proper relative speed to the blank.
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.
1. The improved method of cutting the teeth of worm wheels by means of a
spiral or worm cutter corresponding in pitch and proportions to the worm intended
to gear with the said worm wheel, substantially as set forth.
2. The improved apparatus for facilitating the cutting of the teeth of worm
wheels from a blank of the proper size, whereby the blank to be cut and the spiral
cutter are positively and simultaneously revolved at the proper proportionate
speeds substantially as described and as illustrated in the accompanying drawings.
3. The general arrangement, construction and combination of apparatus for
cutting worm teeth in blanks by means of spiral or worm cutters substantially as
described and as illustrated.
Dated this 22nd day of November 1894.
E. K. DUTTON & Co.,
5, John Dalton Street, Manchester, Agents.