Improvements in Lathe Attachments for Turning Curved or Spherical Surfaces.
Year: 1897

page_text: Date of Application, 26th Feb., 1897-Accepted, 25th Sept., 1897
. COMPLETE SPECIFICATION.
Improvements in Lathe Attachments for Turning Curved or
Spherical Surfaces.
I JOHN THOMAS GODFREY of 80 Industry Road; Darnall, Yorkshire, 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 the first part of this invention is to facilitate the turning of surfaces
which are not parallel with the travel of the slide carriage of the lathe as for instance
crown faced pulleys, hand wheels and spherical work generally.
This is accomplished by travelling the turning tool at a varying radius from the
lathe centres as hereinafter described.
For the purpose of this part of my invention the base of the attachment is bolted
on to the slide rest of a lathe the turning tool being fixed fast by the holder in a slide
rest, said rest having a collar through which passes a shaft provided with an eccentric.
To this shaft is fixed a lever carrying a rod adjustable in a slot. The position of the
rod determines the travel of the tool.
When the attachment is fixed to the slide rest of a lathe and the rod therefrom is
made fast to a fixed point the tool will, while the slide carriage travels parallel to the
bed of the lathe, nevertheless travel so as to describe a curved line to it.
According to a modification for certain classes of work I employ a worin and worm
wheel in place of the eccentrics, the turning tool being fixed in a holder which slides in
the slide rest connected with the worm and worm wheel.
The tool is set to the desired position by altering the position in its slide rest, to
describe a circle or part of a circle of greater or less radius according to whether the
slide rest of the lathe be at rest or travelling, the motion to the worm wheel being
imparted by a handle or an ordinary tappet motion on the worm shaft, or the tool
may be fixed direct to a segment of a worm wheel.
My invention will be fully understood by reference to the annexed drawings in
which at Figures 2 and 3 I show a tool holder C fitted to slide under the action of an
eccentric D, the shaft K of which is fitted in the bearings of the head of a plate A,
this being secured to the slide rest of a lathe. The tool N in the holder C is controlled
in its reciprocatory motion by a rod H having one end adjusted in a slot G of the
lever F, the opposite end of said rod being secured to some fixed point.
Figure 4 is a slight modification of the foregoing but in which the eccentric is
arranged in the plate A instead of in the tool holder C.
If the slide rest has a reciprocating motion by the undergear of the lathe the travel
of the cutting tool is governed automatically and is drawn in and pushed out because
of the connection of its lever F with the rod H the arc of travel being limited from
the adjusted fixed point.
According to the second part of said invention which as before stated is represented
on the same sheet of drawings Figures 5 and 6 and slightly modified at Figures 7
and 8, spherical articles can be turned or parts of same; this will be clear from a
reference to the figures as shown I bolt plate A to the carriage of a lathe and then by
adjusting the tool N by the screw D' the carrier and slide C can be set and be

page_text: operated as desired and to enable the tool to be set for inside or for outside or for
edge cutting the carrier C is held and supported by a circular plate Q the shaft E of
which passes through the head R of the plate A and has a worm wheel S or it may be
a segment only and movable by the worm T as desired by the handle H¹.
In the modification Figures 7 and 8 the article to be turned rotates in a vertical
plane for the tool N to be advanced horizontally and radially by shifting the position
of the combined carrier, tool holder C and worn wheel S.
The tool N can be set and adjusted by screws U. U. Figure 8 if hinged as shown to
the circular motioned plate.
Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed I declare that
what I claim is :-
A Lathe attachment for turning articles as set forth and by the means represented
in the annexed drawings Figures 1. 2. 3 and 4 or the modification shown at
Figures 5. 6. or the modification shown at Figures 7. and 8. as described.
Dated this 26th day of February 1897.
H. GARDNER,
166, Fleet Street, London, Patent Agent,
Agent for the said J. T. Godfrey.