Improvements in Cutters or Drills applicable to Coal or other Materials.
Year: 1891

page_text: Date of Application, 27th Jan., 1891
Complete Specification Left, 26th Oct., 1891-Accepted, 28th Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in Cutters or Drills applicable to Coal or other
Materials.
We, CLAUDE WILLIAM ATKINSON, Civil Engineer, and LLEWELYN BIRCHALL
ATKINSON, Civil Engineer, both of Woodfield Works, Harrow Road, in the
County of Middlesex, do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in cutters or drills applicable to coal or
other materials, either in the form of a cutter bar in which the cutters are disposed
along its length for the purpose of cutting a deep slot in the face of the material,
or in cutters used for the purpose of forming circular holes in the same.
In such cutters or drills as have been heretofore made, the material forming the
cutting edge has been supported in the bar or mandril in one piece, that is to say,
a considerable portion of the cutting tool has to be embedded into the bar which
holds it, thereby entailing a heavy outlay when the cutters are new, and little or
no return to be obtained for worn out cutters; consequently the largest portion of
the material of the cutters is thrown away.
A certain form of cutter is described under No. 1336999 in which the cutters are
formed of separate pieces of steel of a taper form mounted in a special disposition
upon a mandril capable of revolution.
We carry out our invention as follows:--for purposes of description we describe
it in connection with the cutter bar as described in the aforesaid Patent.
In place
of the steel cutters formerly used we substitute a cutter-holder in the form of a
projecting shank, which is mounted upon the cutter bar, preferably by screwing it
into the same; but it may be attached by means of a taper shank in the same way
as the cutters described in the aforesaid Patent. One great advantage of screwing
these holders into the bar is that a great reduction is effected in the amount of
material of the bar that has to be removed for the purpose of attaching the cutters.
At the outer end of this shank or holder a hole is arranged, which, in the case of a
cutter bar for cutting a deep slot, will be at right angles, or about right angles, to
the axis of the holder and bar. This hole may be round, square, polygonal,
parallel, or taper, but we prefer to make it round and taper, in order to facilitate
the detachment of the cutter.
This cutter may be made of varying shapes to suit the material to be cut, and is
mounted in the hole at the end of the shank, in such a way that the pressure
produced by cutting tends to force it into its holder.
The tool may be so shaped, or the hole into which it is mounted so inclined, as
to allow the cutting edge to project radially beyond the shank.
It is obvious that this method of mounting the cutters is considerably cheaper
than those used heretofore, as the amount of cutting edge material used in the bar
is reduced very considerably, say to about . Further, that when the cutting
edge has become blunt, it can be turned about its axis, offering a fresh cutting
edge; and when the cutting edge has been completely used, it is cheaper to knock
it out and insert a fresh cutter, rather than grind the old one. Our invention is
equally applicable for purposes of face cutting, such as that required for drilling a
hole of 4 ins., or any other dimensions, in which case we may arrange one or more
cutters on a cutter bar, the said bar being supported in a small hole previously
made

page_text: The cutter or cutters are so arranged as to cut an annular groove or grooves
about the axis of rotation.
Dated this 27th day of January 189.1.
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Cutters or Drills applicable to Coal or other
Materials.
We, CLAUDE WILLIAM ATKINSON, Civil Engineer, and LLEWELYN BIRCHALL
ATKINSON, Civil Engineer, both of Woodfield Works, Harrow Road in the County
of Middlesex, do hereby declare the nature of our invention and in what manner
the same is to be performed to be particularly described and ascertained in and by
the following statement:-
This invention relates to improvements in cutters or drills applicable to coal or
other materials either in the form of a cutter bar in which the cutters are disposed
along its length, or in the form of a disc the cutters being arranged around the
periphery of the disc, for the purpose of cutting a deep slot in the face of the
material, or in cutter bars used for the purpose of forming circular holes in
the same.
In such cutters or drills as have been heretofore made the material forming the
cutting edge has been supported in the bar, disc, or mandril in one piece that is to
say a considerable portion of the cutting tool has to be embedded into the bar
which holds it, thereby entailing a heavy outlay when the cutters are new and
little or no return to be obtained for worn out cutters consequently the largest
proportion of the material of the cutters is thrown away.
We have described a cutter or drill in another application No. 13369 and dated
24th day of August 1889 in which the cutters are formed of separate pieces of
steel of a taper form mounted so as to be frictionally held in a special disposition
upon a mandril capable of revolution.
In order that our invention may be the better understood we will now describe
the same in relation to the drawings hereunto annexed reference being had to the
letters and figures marked thereon the bar of the taper form as before referred to
being used for the purposes of description so as to show one method of carrying
out our invention.
Fig. 1 is a side view of a cutter bar with tool holders and tools attached.
Fig. 2 is a section of the bar showing a tool holder partly in section and the tool
in section removed therefrom.
Fig. 3 is a view of the tool holder removed from the bar.
Figs. 4, 5, & 6 are views of a modified tool.
In place of the steel cutters formerly used we substitute a cutter holder A in the
form of a projecting shank which is mounted upon the cutter bar B preferably by
screwing it into the same, but it may be attached by forming the shank taper so
as to be frictionally held in the bar in a similar manner to the cutters before
described.
One great advantage however of screwing these holders A into the bar B is that
a great reduction is effected in the amount of material of the bar that has to be
removed for the purpose of attaching the cutter.
At the outer end of this shank or holder A, the hole C is arranged which in
the case of a cutter bar for cutting a deep slot in the face of the coal or other
material will be at right angles or about right angles to the axis of the holder
and bar.
This hole C may be round, square, polygonal, parallel, or taper but we prefer to

page_text: make it round and taper in order to facilitate the attachment and detachment of
the cutter therewith.
The cutter D may be made of varying shapes to suit the material to be cut and
is mounted in the hole C at the end of the holder A in such a way that the pressure
produced by cutting tends to force it tighter into its holder.
The cutters as shown in Figs. 1 and 2 are of a circular cupped form having a
taper shank which engages with the taper hole C in the holder A.
The tool is so shaped or the hole is so inclined if necessary as to allow the
cutting edge to project radially beyond the shank, A. The great advantage of
this circular cupped tool is that as one part of the circumferential cutting edge
becomes worn away, the cutter can be withdrawn from its holder A and turned so
as to present a fresh cutting edge to the material to be cut until the whole circum-
ference has been worn away.
In Figs. 4, 5, and 6 we show a form of cutter having 2 cutting edges only the
cutter being of the diamond shape, and having a taper shank d to attach it to the
holder. The front face of each half of the cutter is ground off at an angle so that
the cutting edge e' leads a trifle in advance of the e. When the one side of the.
cutter has become worn the cutter is knocked from its holder, and the cutting edges
turned end for end.
✓
A very high efficiency of cutting effect is obtained with the diamond shaped
cutter if the holder A is so adjusted upon the bar that the point f of the cutter
(Fig. 6) revolves in a different plane of revolution to the point f₁; the effect of
this is, that the point cuts a groove in the coal and the edge between ƒ and fi
breaks off the coal between one groove and another, the result being that the
actual amount of coal that is cut is very small, the majority being broken off, and
the power required for driving the machine is consequently much reduced.
It is obvious that this method of mounting the cutters is considerably cheaper
than those used heretofore, as the amount of cutting edge material used in the bar
is reduced very considerably say to about go of that used where the cutters are
mounted in the bar direct, and further as before described, when the cutting edge
has become blunt it can be turned about its axis offering a fresh cutting edge and
also when, the cutting edge has been completely used up it is cheaper to knock it
out, and to insert a fresh cutter rather than grind the old one.
These cutters may be made of chilled cast iron or steel, but we prefer to use the
former as being considerably cheaper.
As shown in Fig. 1 it will be noticed that the tool holders A are arranged upon
the bar in double spiral form, that is to say one way on a left hand spiral of large
pitch say once the length of the bar, and about four spirals, and the other a number
of right hand spirals of short pitch.
It is obvious that our invention is equally practicable to tools for purposes of
face cutting such as that required for drilling a hole of 4 inches or any other
dimension in which case we arrange one or more of the cutters as before described
on the cutter bar, the end of the bar being supported in a small hole previously
made.
The cutters and their holders are so arranged in respect to the bar that they cut
out an annular groove or grooves about the axis of rotation.
Having now particularly described and ascertained the nature of our inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:-
1st. In a machine for cutting coal or other material in which the cutting is
effected by rotary motion a tool holder or holders each adapted to detachably
hold a tool in combination with the rotating support on which the tools are
carried.
2nd. In a cutter bar or drill the combination with a parallel or taper bar, of a
series of tool holders supported on the said bar and separate tools having a taper
shank detachably attached to the said tool holders substantially as described.

page_text: 3rd. In a cutter bar or drill the combination with a parallel or taper bar,' of a
series of tool holders arranged on the bar, in spirals in opposite directions and of
different pitch, and diamond shaped cutters detachably attached to the said holders
by a taper shank and so disposed in relation to the bar that the front and back
corners of the cutting edge rotate in different planes of revolution substantially as
and for the purpose specified.
4th. In a cutter bar or drill, a holder mounted upon the bar in combination with
a cutting tool detachably attached to the said holder and adapted to be turned
about the axis of its support on the said holder so as to present a series of fresh
cutting edges substantially as described.
5th. The construction and arrangement of a cutter bar with tool holders and
tools substantially as described and illustrated in the accompanying drawings.
Dated this 26th day of October 1891.
FELL & WILDING,
I, Queen Victoria Street, London, E.C., Agents for the Applicants.