EXPANDING MANDREL."
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by the said Joseph Harrison at the
Office of the Commissioners of Patents on the 9th March 1881.
JOSEPH HARRISON, of Manchester, in the County of Lancaster.
EXPANDING MANDREL."
:
"AN IMPROVED
In performing my Invention I use a flanged metal boss, on the outside of which
a screw thread is cut, and through the centre of which is a taper screwed hole; a
taper plug screwed at the end is fixed in this hole and projects from the front of
the boss; the projecting portion of the plug is also taper, the greatest diameter of
the plug being at the face of the boss. On this boss I place three or other number
of segments rounded on the outer and grooved on the inner side, which together
form the portion of the mandrel on which the wheel, pulley, collar, or other article
to be turned is held. There are projections on the sides of the segments to keep
them central; these segments are flanged, and the flanges rest inside the rim of a
cap which is screwed on to the boss and tightened to secure the article on the
mandrel; when the cap is unscrewed the article is released. The flange of the boss
is secured to the face plate of the lathe, and the plug is countersunk so that the
lathe centre may fit in it.
This improved mandrel may be used for holding articles to be operated upon by
various machines.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Joseph Harrison in the Great Seal Patent Office on the
9th September 1881.
JOSEPH HARRISON, of Manchester, in the County of Lancaster. "AN IMPROVED
EXPANDING MANDREL."
In performing my Invention I use a flanged: metal boss, on the outside of which
a screw thread is cut and through the centre of which is a taper screwed hole. A
tapered plug ór spindle screwed at the end is fixed in this hole and projects from
the front of the boss; the projecting portion of the plug is also taper, the greatest
diameter of the plug being at the face of the boss. On this plug or spindle place
three or other number of segments rounded on the outer and grooved on the inner
side, which together form the portion of the mandrel on which the wheel, pulley,
collar, or other article to be turned is held; there are projections on the sides of the
segments to keep them central. These segments are flanged, and the flanges rest
inside the rim of a cap which is screwed on to the boss and tightened to secure the
article on the mandrel; when the cap is unscrewed the article is released. The
flange of the boss is secured to the face plate on the lathe, and the plug is counter-
sunk.so that the lathe centre may fit in it. This improved mandrel may be used for
holding articles to be operated by various machines.
And in order that my Invention may be fully understood and readily carried
into effect, I will describe the accompanying Sheet of Drawings, reference being
had to the Figures and letters marked thereon.
Fig. 1 is a sectional elevation of my improved expanding mandrel; Fig. 2 is an
end view of the three segmental dies or jaws;. and Fig. 3 is a plan of a segmental
die; Fig. 4 is a section of my expanding mandrel without the flange.
Fig. 5 is a section of my improved mandrel with the flange and taper plug formed
in one piece.
a is the flanged metal boss; b is the taper plug or spindle which is screwed or
otherwise fixed tightly into the flanged boss; c, c, are the dies formed concave.on
the inner surface to fit the taper plug or spindle, and convex on the outer surface,
all parts of the periphery of the dies being equidistant from the centre of the plug b
except where they are flanged; d is the cap, the rim of which enters between the
flanges on the dies c. This cap is chased to fit the screw thread on the boss a.
Bolts are passed through the flange at 6¹ to secure the mandrel.to the face plate of
the lathe or other tool, and the annular projection 62 on the flange is fitted in a
corresponding recess in the face plate to ensure the mandrel running.true. I form
projections c¹ (see Fig. 3) on the sides of the dies at the end to keep them from
resting too close together and leaving a large space at the periphery.
The mandrel shown on Fig. 4 may be placed in the lathe or other tool centres
and turned by "dogs" fixed on the end as on an ordinary mandrel if desired. The
boss and the plug are made by preference of one piece, and the cap and dies are
fitted as before described. This mandrel may be fitted into the taper hole of the
headstock or spindle of machine tools or made to screw on to the nose of the tool
spindle.
Fig. 5 shows a simpler form of my improved mandrel with the plug and
flanged boss in one piece; the dies and cap are fitted as described in reference to
Fig. 1.
When a collar or other article is placed on the disc c the cap d is tightened on the
boss until the dies are drawn so far up the plug as to hold the article securely on
the dies. When it is to be removed the cap is slackened and the article is released
and can at once be taken off. If the flange have notches cut in the edge or holes
drilled an equal distance apart, it can then be used as a dividing plate.

page_text: My improved mandrel is applicable to all classes of machine tools for holding
pulleys, wheels, collars, and all other articles which can be held on a mandrel. It
is specially adapted to hold such hollow articles as railway buffers and screw jack
heads which have a hole that does not extend quite through them whilst they are
being turned and finished in the lathe or other machine.
The dies or split bushes may be parallel, taper, or of any configuration, or flat, to
enter a square hole on their outer surface, and in order to change the dies it is only
necessary to unscrew the cap and replace one set of dies by another of different size
or shape. Split collars or bushes bored to fit the dies on the mandrel can be put on
them in order to hold articles with holes of larger diameter.
Another modification consists in dispensing with the flange and adapting the
expanding mandrel for use in the lathe or other tool centres. In this case I prefer
to make the body of the mandrel and the spindle of one piece; the cap and split
dies are made as before described.
The mandrel will also hold the tool or tools for sinking artesian wells. For this
purpose I flute the dies or segments and place a bush over the shank of the tool to
secure the boring or other tools.
Having stated the nature of my Invention and described the manner of performing
the same, I declare that I claim,―
1. The combination and arrangement of the parts forming an improved expanding
mandrel, as described and shown on Fig. 1.
2. The split dies bored with a taper hole in combination with a taper spindle
and the nut or cap for operating the same, as shown and described.
In witness whereof, I, the said Joseph Harrison, have hereunto set my hand
and seal, this Eighth day of September, One thousand eight hundred
and eighty one.
JOSEPH HARRISON. (L.S.)