Improvements in Tool-holders for Machine-tools.
Year: 1893

page_text: Date of Application, 18th Aug., 1893-Accepted, 23rd Sept., 1893
COMPLETE SPECIFICATION.
Improvements in Tool-holders for Machine-tools.
I JOHN MADAM, of 9 Sea Terrace, Middleton, West Hartlepool, in the
County of Durham, 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 :-
My invention relates to improvements in tool-holders for machine-tools such as
are used in lathes, drilling machines, planing machines etc., and has for its object
to keep the tool firmly in position when in operation, and also to prevent waste and
to economise the use of steel forming such tools, as by means of my invention short
pieces of steel even of two inches only in length may be used with efficiency.
According to my invention the shauk or stem of the holder is drilled out for the
insertion of a thrust-pin which is forced against the rear end of the tool by means.
of a screw screwing into the end of the shank or stem thus preventing all possibility
of shifting on the part of the tool.
The tool is held in an enlarged conical portion of the holder, which is provided
with four or other suitable number of longitudinal slits to give resiliency to such
portion.
Over this conical portion fits a coned ring or washer acting as a clamp to cause
the said portion to grip the sides of the tool when the ring or washer is forced by
means of a nut screwing on a threaded portion of the shank or stem, a lock-nut
keeping it from shifting.
A small set-screw is screwed into the coned portion of the holder so as to bear
upon the tool and assist in keeping it rigid.
And in order more particularly to understand my said invention and the manner
of carrying it into practical effect, I will describe the same with reference to the
accompanying sheet of drawings in which Fig. 1 is a side view of my improved
tool-holder and Fig. 2 a front end view thereof, Fig. 3 being a longitudinal section
and Fig. 4 a cross-section on the line x. x of Fig. 3. a is the shank or stem of the
holder made hollow or drilled out for the reception of the thrust-pin b; c is a
screw screwing into the end of the stem a, and bearing against one end of the pin b,
the other end of which bears against the rear end of the tool d, a lock-nut e
keeping the parts rigid. is an enlarged coned portion formed on the other end
of the stem through which is screwed a small set-screw g bearing against one side
of the tool d for keeping the latter rigidly in position and from being forced
forward by the pin b. The coned part is formed with slits fcut longitudinally
therein for giving it resiliency for gripping the sides of the tool d which latter is
placed in a recess in a part f corresponding in shape to the cross-section of the
said tool.
is a loose coned ring or washer fitting on to the cone and acting as a clamp to
cause the latter to firmly grip the tool upon screwing up the nut i against the end
of the ring or washer, a lock-nut k preventing the nut i from shifting and both
nuts being mounted upon the screw-threaded portion a' of the stem a.
To the forward end of the cone fis secured by means of studs l. la circular
plate or washer m for giving still further rigidity to the tool-holding device.
As will be seen, by means of my invention, very small pieces of steel may be
used for forming the tool or cutter-bar, thus greatly decreasing the cost of
manufacturing such tools and permitting the use of small scrap steel for that
purpose the tool can also be readily and easily removed and another one
expeditiously fixed in position; it is also evident that my improved tool-holder
may be used not only in lathes, but also in drilling machines, planing and other
shaping and cutting machines.
:

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
1. In a tool-holder, the combination of the hollow stem or shank a, the coned
portion provided with slits f¹, the set-screw g, the coned ring or washer h, the
nuts i.k and threaded portion a', the thrust-pin b, the screw e and lock-nut e, and
the circular plate or washer m, all substantially as described and for the purpose
specified.
2. The improved tool-holder substantially as described and shown in the
accompanying drawings.
Dated this 18th day of August 1893.
HUGHES & GONNE,
12, Basinghall Street, E.C., Agents for the Applicant.