Improvements in Cutters or Drills, Applicable to Coal or other Materials.
Year: 1889

page_text: Date of Application, 24th Aug., 1889
Complete Specification Left, 27th May, 1890-Accepted, 23rd Aug., 1890
PROVISIONAL SPECIFICATION.
Improvements in Cutters or Drills, Applicable to Coal or other
Materials.
HANS RENOLD, Brook Street, Manchester, Engineer, WALTER THOMAS GOOLden,
Electrical Engineer, LLEWELYN BIRCHALL ATKINSON, Civil Engineer, and SYDNEY
CHARLES GILBEY GOLD, Electrical Engineer, all of Woodfield Road, Harrow Road,
London, trading under the Firm of W. T. Goolden & Co., 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, and has for its object the formation of a cutter or drill, enabling the
best shape or configuration, and the most suitable material to be used for each part.
In such cutters or drills as heretofore made, the cutting edge and the supporting
bar have either been made in one piece, necessitating the use of material unsuitable
for both, or the cutters have been formed separately and attached by screws, wedges,
or dovetails, to the bar, causing the same to be complicated and expensive, and of
shapes inefficient for the purpose in view.
In the improved construction the bar or cutter shaft is composed of mild steel or
iron of great tenacity and toughness, either straight or taper or any other form.
The cutter teeth are formed of separate pieces of steel which are made of a special
temper & hardness, best suited for the material to be cut.
The cutter shaft has a series of taper holes drilled in it, and into these holes the
cutters are driven, and hold fast by friction alone. The action of the cutter when
working has a tendency to drive these cutter teeth tighter into their holes, especially
when their axis are so arranged as not to pass through the centre of the bar, but
tangential. The distribution of the cutter teeth over the bar is such that each follows
its fellow at a distance of more or less than one quarter of a revolution, or other
fraction of a revolution, so that there is not more than one cutter tooth at a time in
a line drawn on the bar parallel to the axis, which has the effect of distributing the
cutting strains all over the circumference as well as the whole length of the
cutter bar.
In other words there will only be one, or at the utmost, two cutter teeth striking at
the same time, a hard layer of pyrites should such be in the coal.
This arrangement of cutters gives them a corkscrew or spiral form, which has a
tendency to draw out the cuttings as the bar revolves, especially as the ground front
surfaces of the cutter teeth are similarly inclined, and help to push out of the hole
the small coal or other material being worked upon, thus somewhat liberating the
cutter.
The form of the cutter point varies with the material to be cut, but it is so arranged
as to be ground on the front face to maintain a constant cutting angle, and to have
sufficient metal backing the cutting edge to give the requisite strength, and to carry
off the heat developed.
When the cutter teeth are used up by constant grinding, they can easily, and at very
little cost, be replaced by new ones, forming with the old cutter bar practically a new
cutter again.
1000
HANS RENOLD.
WALTER T. GOOLDEN.
LLEWELYN B. ATKINSON.
SYDNEY C. G. GOLD.
W. T. GOOLDEN & Co.

page_text: COMPLETE SPECIFICATION.
Improvements in Cutters or Drills, Applicable to Coal or other
Materials.
We, HANS RENOLD, WALTER THOMAS GOOLDEN, LLEWELYN BIRCHALL ATKINSON,
and SYDNEY CHARLES GILBEY GOLD, of Woodfield Road, Harrow Road, London, 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 and has for its object the formation of a cutter or drill enabling the
best shape or configuration and the most suitable material to be used for each part.
In such cutters or drills as heretofore made the cutting edge and the supporting
bar have either been made in one piece necessitating the use of material unsuitable
for both or the cutters have been formed separately and attached by screws, wedges,
or dovetails to the bar, causing the same to be complicated and expensive and of
shapes inefficient to the purpose in view.
In the improved construction the bar or cutter shaft is composed of mild steel or
iron of great tenacity and toughness either straight or taper or any other form.
The cutter teeth are formed of separate pieces of steel which are made of a special
temper or hardness best suited for the material to be cut. The cutter shaft has a
series of taper holes drilled in it, the taper being between 1 in 29 and 1 in 30 and
into these holes the cutters are driven and hold fast by friction alone. The action of
the cutter when working has a tendency to drive the cutter teeth tighter into their
holes, especially when their axes are so arranged as not to pass through the centre of
the bar, but tangentially. The distribution of the cutter teeth over the bar is such
that each follows its fellow at a distance of more or less than one quarter of a
revolution, or other fraction of a revolution, so that there is not more than one cutter
tooth at a time in a line drawn on the bar in a plane containing the axis which has
the effect of distributing the cutting strains all over the circumference as well as in
the whole length of the cutter bar.
In other words should the cutter meet with any hard obstacle not more than one or
at most two teeth will strike it at a time.
This arrangement of cutters gives them a corkscrew or spiral form which has a
tendency to draw out the cuttings as the bar revolves, especially as the front or side
surfaces of the cutter bar are shaped so as to be similarly inclined, and help to push
out the cuttings and somewhat liberate the cutter.
The form of cutter point varies with the material to be cut, but it is so arranged as
to be ground on the front face to maintain a constant cutting angle, and to have
sufficient metal, backing the cutting edge to give the requisite strength and to carry
off the best developed.
When the cutting teeth are used up by constant grinding they can easily and at
very little cost be replaced by new ones, forming with the old cutter bar practically a
new cutter again.
In order that my invention may be the better understood I now proceed to describe
the same in relation to the drawings hereunto annexed reference being had to the
letters and figures marked thereon. Like letters refer to like parts throughout the
drawings.
Figure 1 is an outside elevation of my cutter bar provided with taper holes for
cutters.
Figure 2 is an end view of the same.
Figure 3 is a detail of the cutters with taper shanks.
Figure 4 is an end view of bar with a cutter in place.
The cutter bar is provided with a flange d for coupling it to a cutting or drilling
machine. It is provided with a series of taper holes distributed along its length at
short intervals along lines representing left hand spirals or threads with a pitch of the

page_text: length of the bar about 4 threads being used. The relative positions of the holes are
so placed that each successive cutter taken circumferentially is placed a little in
advance of the cutter of the adjacent thread so that there is never more than one
cutter in a circumferential ring about the cutter bar.
The taper holes through the bar do not therefore foul each other and the cutters
taken as nearly circumferentially as possible across their left handed pitch line
settings form a right handed thread, which materially aids self-delivery of cuttings.
The cutters shown at Figure 2 are sharpened by being ground at the end faces a,
but other forms may be used which can be ground on the front faces b.
Figure 4 shows the arrangement of the cutter where the axis of the cutter does not
pass through the bar, but tangentially to a surface inside the bar thus giving the
cutter greater tendency to be driven in by the cutting action.
A cutter or cutters may if necessary be driven in the end C in Figure 1 either
centrally or at an angle to the axis.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1st. In a cutter bar or drill the combination of a parallel or taper bar provided with
a flange for attachment to the cutting or drilling machine of a series of taper holes
for the cutters with taper shanks frictionally held arranged in parallel spiral pitch
lines making left handed screw of about a pitch once the length of the bar with the
holes interspaced in the various parallel series so as to form a right handed screw of
short pitch.
2nd. In a cutter bar or drill for cutting coal or other material the arrangement of
cutters around the cutter bar in.taper holes the axis of the said holes being tangential
to the surface inside the bar, so that the cutting action of the cutter tends to force it
tighter into its hole.
3rd. The construction and arrangement of a cutter bar and cutters, substantially as
described and illustrated in Figures 1, 2, 3 and 4.
FELL & WILDING,
1, Queen Victoria Street, Agents for the Applicants.
ለሶስ
LOTH TO Con
Bona nanc