Improvements in Expanding Mandrils for use with Lathes or other Tools.
Year: 1892

page_text: Date of Application, 16th May, 1892-Accepted, 18th June, 1892
CUMI LEIE DI MUITIVATION
Improvements in Expanding Mandrils for use with Lathes or
other Tools.
I WILLIAM MARSDEN KERMODE of 27 White's View, Bradford, in the County
of York, Secretary, 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 :—
This mandril is designed to secure a ready means of accurately centreing in a
lathe or similar tool, articles of circular shape, and to hold them firmly in such
central position during the time they are being operated upon.
Referring to the accompanying sheet of drawings
Figure 1 is a section through the mandril and Figure 2 represents half an end
view.
The mandril consists of four parts which may be made of the metals hereinafter
mentioned or of other metals or alloys which may answer the same purpose.
The part marked A on drawings is the main body of the mandril and may be
obtained by casting or otherwise and is firmly screwed on to the lathe spindle.
On part of its periphery is traced a left handed screw thread which engages with a
corresponding thread chased round part of the interior of boss of hand wheel B.
The remaining part of boss of hand wheel B has a right handed thread, which
engages with a similar thread traced round the base of circular casting C which is
here supposed to be made of brass. The part C is prevented from rotating by a
small pin D securely fastened to it and fitting into a longitudinal slot in the casting
or part A. I make the part marked E on drawing, to secure into the main body
of the mandril, pin holes being provided for a wrench. That portion of the part E
which extends beyond the screw E', is conical in shape, the smaller diameter of
the cone being next, and corresponding in size to the part A at that point. The
part C has several longitudinal slits cut into it and has a shoulder at G, which
acts as a stop for the articles to be placed on the mandril.
The action of the mandril is as follows. The article which is to be operated
upon is placed on the brass mandril C until it rests against the shoulder G, which
may be of any desired shape. When in this position, the hand wheel B, is rotated,
causing it to disengage slowly from the part A, and also causing the part C, to
advance slowing upon the cone E as it is prevented from rotating by the pin D,
fitting in the slot in the part A. As the part C advances it is expanded
gradually by the cone E, which remains stationary, the slits F permitting of this
expansion. As a result the article which was placed upon the mandril C, is
gripped tightly as the mandril expands, and the outward pressure is exercised from
all points in the circumference of the mandril. When the article has become held
sufficiently firmly it will be in readiness for being operated upon in the usual
manner and will be accurately centred and in correct position in all ways.
The different parts of the mandril may be finished upon the lathe upon which it
is to be used, so as to ensure all its parts working truly in connection with the
lathe spindle.
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. An improved expanding mandril, which may be used in connection with a
lathe or other tool, and made to clip the articles to be operated upon by rotating a
wheel, which by means of a right and left handed screw and cone, engages and
disengages the work or article, substantially as herein shewn and set forth.

page_text: 2. In a mandril or apparatus for holding articles during operation thereon with a
lathe or other tool the arrangement or combination and use of parts substantially
as set forth.
'
Dated the 16th day of May 1892
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.