Improvements in and relating to Stone Dressing Tools.
Year: 1896

page_text: This Print is in accordance with the Original Specification as it stands after Amend-
ment (under Section 11 of the Patents, &c., Act, 1883), as required by the
decision of the Chief Examiner of the 23rd day of December 1897.
Date of Application, 30th July, 1896
Complete Specification Left, 31st May, 1897-Accepted, 3rd July, 1897
PROVISIONAL SPECIFICATION.
Improvements in and relating to Stone Dressing Tools.
I, JOHN DOBBIE, Contractor of Old Bridge End, Leith, county of Midlothian, do
hereby declare the nature of my invention to be as follows:-
My invention relates to Stone and Marble dressing Tools having interchangeable
and reversable cutting parts, and used either for hand or machine purposes.
The handle or holder is recessed or socketted at the end which is to hold the
cutter, such recess usually being made to taper inwardly, and communicating with a
slot made through the handle for the purpose of releasing the cutters when they
require changing.
The cutters which are preferably made double edged so that when worn they can
be reversed, are held between two jaws, which are tapered and otherwise outwardly
correspond with and fit into the recess or socket of the handle so that when pressed
into the socket they are firmly held for working purposes.
The cutters are preferably made from thin steel having one or more beads or
ridges formed transversely across the centre or thereabouts and the inner faces of
the jaws are made to correspond with transverse grooves to receive the beads or
ridges, which with the frictional contact upon the plain surface of the cutters enable
the cutters to be held with great firmness and solidity.
The beads, ridges, or projections upon the cutters may be solid and formed at the
time of rolling the steel, or they may be produced by bending, stamping or indenting
flat steel. In order to preserve the cutting quality of serrated cutters I serrate theni
in a peculiar manner, forming at the corner of the cutter a broad faced or square
tooth with the pointed teeth in the centre, and in some cases I use a central square
tooth as well as those at the corners, the remainder being pointed.
Dated the 29th day of July 1896
ROBT. F. DRURY, C.P.A.,
Bank Buildings, George Street, Sheffield, Agent for Applicant.
Improvements in and relating to Stone Dressing Tools.
I, JOHN DOBBIE, Contractor, of Old Bridge End, Leith do hereby declare the
0 nature of this invention and in what manner the same has to be performed, to be
particularly described and ascertained in and by the following statement:-
This invention relates to Stone and Marble dressing tools having interchangeable

page_text: and reversible cutting parts, or blades, and which may be constructed to be used
either by hand or by machinery.
Such Tools made according to my invention are illustrated in the accompanying
drawings, similar letters of reference indicate similar parts in any of the figures.
Fig. 1, is a front elevation, and Fig. 2, a side elevation of a stone dressing tool
fitted with a pair of jaws and an improved cutter.
Fig. 3, front and side views of a pair of jaws.
Fig. 4, side view of a pair of jaws with ribs and grooves, and the inner face of
each jaw.
Fig. 5, enlarged views of my improved cutter with a single rib.
Fig. 6, similar views of a cutter with two ribs. My invention relates more
particularly to the construction of the reversible cutters used in these tools, and in
the means for holding such cutters securely and so as to avoid damaging the upper
cutting edge when the tool is in use.
The handle which I prefer is illustrated in Figs. 1 & 2, having a recess in the lower
end to receive a pair of jaws between which the cutter is held.
The cutters are preferably made with two cutting edges E, & E³, to render them
reversible, and with a rib R, projecting from both sides as shown in Fig. 5, or with
two such ribs as shown in Fig. 6.
These ribs may be solid as shown, or they may be formed upon one side only by
stamping the flat metal into a grooved die, which leaves the opposite side hollow
or concave.
The teeth of such cutters have hitherto been made all of one size and width, but
in order to retain the cutting quality of the cutter as long as possible, I combine
with the ordinary teeth a number of broad teeth B, arranged to suit the various
classes of work, four methods being shown in Figs. 5 & 6.
This combination of broad faced teeth with the more pointed ones P, gives support
to the weak teeth, and lengthens the life of the cutter.
The jaws J Fig. 3, are slightly tapered at the top to enable them to fasten securely
in the recess of the handle by wedging; they are made with one or more grooves G,
across their inside faces to receive the rib or ribs R, of the cutters when placed in
position, but for cutters having hollow or concaved ribs as before described, I use the
jaws shown in Fig. 4 one side being provided with grooves G, and the opposite side
having fillets or ribs F, between which the cutters are gripped.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I wish it to be understood
that I am aware that it has been previously proposed to construct a chisel for cutting
stone & the like with jaws for holding the cutter fixed in a recess in the lower end
of the handle, and also to use reversible toothed cutters, & I do not claim these but
I declare that what I claim, is:-
'
1-In combination with a handle such as shown in Figs. 1 & 2, a pair of jaws made
to fit into a recess in the said handle, having one or more grooves across their
inside faces to engage with corresponding ribs upon the cutters they are intended
to hold, substantially as hereinbefore described and shown.
2-For stoneworkers Chisels, a pair of jaws J, provided with one or more grooves G,
in the face of one jaw, and one or more ribs F, on the face of the other jaw, as
hereinbefore described and shown.
3-In reversible cutters for stoneworkers Chisels, the combination of a number of
broad faced teeth with the usual pointed or narrow faced teeth, as hereinbefore
described for the purpose specified, and shown in Figs. 5 & 6.
Dated the 26th day of May 1897
ROBT. F. DRURY,
Agent for Applicant.