Year: 1896

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (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 Loft 21st May 1007
1007
I, JOHN DOBBIE, Contractor of Old Bridge End, Leith, County of Midlothian, do
hereby declare the nature of my invention to be as folows:-
This invention relates to the handles, holders or sockets used for holding
interchangeable cutters for dressing stone, marble and the like either by hand or
power.
Hitherto in the use of such tools it has been found in practice that the worn end
of the cutter becomes "jumped up" or thickened in use, and will not when reversed
fit properly in the recess prepared for a perfect end, and usually a second handle
with a larger slot has been required.
I propose to make the handle or other holder for the cutters preferably of steel on
account of its strength and elasticity, and I make the slot between the two jaws in
which the cutter is to be held wider than the cutter, and provide suitable means
such as a screw bolt passing through the two jaws, or a sliding ring, or equivalent
means to compress the jaws upon the inserted cutter and hold it firmly for work..
When the blade is to be reversed, the jaws are released and spring apart by their
resiliency and thus will admit and hold a thickened cutter.
The cutters may be of various sections and serrated or plain.
ROBT. F. DRURY, C.P.A.,
Bank Buildings, George Street, Sheffield,
Agent for Applicant.
Dressing Stone, marble, and the like.
I, JOHN DOBBIE, Contractor, of Old Bridge End Leith do hereby declare the
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:-
My invention relates to the handles, holders, or sockets for holding interchange-
able cutters or blades for dressing stone, marble or like substances, either by hand
labour or by the aid of machinery.
Hitherto in the use of such tools it has been found in practice that the worn end
D011

page_text: of the cutter becomes thickened or "jumped up" and when reversed will not fit
properly into the recess or slot prepared for a perfect or unused end, and therefore
a second handle with an enlarged recess has usually been required...
I therefore propose to construct the cutter holder and the cutters for same as
shown in the annexed drawings in which similar letters of reference indicate similar
parts in any of the several figures.
Fig. 1, is a front elevation, and Fig. 1, is a side elevation of a Chisel with a
single transverse groove in the mouth, complete with a cutter provided with
a single ridge, and Fig. 1d, is a vertical section of the same handle.
Figs. 2 & 2ª, are end views of the nose of a Chisel provided with two transverse
grooves.
Fig. 3, the nose of a Chisel with another form of transverse groove.
Figs. 4 & 5, side and end views of a cutter with a single ridge or rib projecting
from both sides.
Fig. 6, end view of a cutter with two ridges.
Fig. 7, end view of a cutter with two hollow ridges upon one side.
Fig. 8, end view of a cutter with one hollow ridge.
Fig. 9, views of the gripping bolt and nut..
In carrying out my invention I preferably make 'the handle part A, A2, A3, of
steel as being strong and resilient, and I split or divide it longitudinally. from the
rose B, up to any desired point such as C, thus forming two connected jaws A³,
and A3, which may be closed by the application of force, and which when the
closing force is removed will by reason of their resiliency again resume their open
position.
Between the inner faces of the two jaws A2 and A³, and approaching the nose B,
I make a transverse groove D, see Fig. 1b part being made in A2, and part in A³,
to receive a correspondingly shaped ridge or rib R, formed upon the cutter, see
Fig. 5, and above this groove and at a right angle to it I make a bolthole E, passing
through both jaws to receive the bolt and nut shown in Fig. 9.
In the jaw A³, the hole is tapered to receive the tapered head F, of the bolt, and
squared to receive the square collar G, to prevent the bolt being moved by the
action of the nut; the jaw A3, has a tapered hole to receive the nut H, shown in
Fig. 9.
By this construction of the bolt and the bolthole, I avoid forming a screwthread in
either of the jaws and I obtain a compact bolt and nut, supported by and protected
within the handle, not liable to be damaged, and readily replaced at a small cost
when worn out.
Referring to Figs. 2 & 2, instead of a single groove I may use two such
grooves D&D, by which I am enabled to use a cutter with a greater depth of
blade, thus a new cutter would have its ridge or rib inserted in the upper groove D³,
as shown in Fig. 2; and when the projecting part of the blade became too short
from wear, the cutter would be withdrawn by releasing the bolt, be re-sharpened
if necessary and replaced with the rib in groove D, as in Fig. 2, the same process
being repeated with the opposite blade. A double ribbed cutter Fig. 6 may also
be used.
A cutter of the section shown in Fig. 7, may also be used in the above described
handle; this form of cutter can lie 'readily made by stamping it to form between
dies in contradistinction to rolling.
Referring to Fig: 3, I construct this handle with a groove I, in one jaw, and a
rib J, on the other jaw, arranged to admit and grip a cutter formed as shown in
Fig. 8.
The percussive impact when in use is taken by the rib or ridge R, gripped within
the groove, in conjunction with the frictional grip of the jaws upon the flat of the
blades, and as the space between the jaws A3 and A3, above the groove D, is wider
than the cutting edge of the blade, the thickening of the edge by the repetition of
blows during use will not prevent its insertion between the jaws, nor interfere
with it being safely held by the jaws, an important feature not hitherto accom-

page_text: plished with reversible cutters, as usually two handles have been required, one
having a wider slot than the other.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I wish it to be under-
81cod that I am aware that it has been previously proposed to construct chisels
for cutting stone and the like with handles split or divided longitudinally to form
jaws, and also to use reversible toothed cutters, and I do not claim these, but
I declare that what I claim, is:-
1-A Handle for holding reversible cutters for working on stone, wood, and
other materials, having jaws provided with one or more transverse grooves to receive
corresponding ribs formed upon the cutters as herein before described and shown.
2 In combination with a semi-divided handle for holding interchangeable
cutters for stone and the like, a gripping bolt having a taper head F, a squared
ccllar G, or other equivalent means to prevent the bolt turning when in position,
and a tapering nut H, fitting into a correspondingly shaped opening made through
the jaws A & A³, of the handle, as hereinbefore described and shown.
Dated the 28th day of May 1897
ROBT. F. DRURY, C.P.A.,
Agent for Applicant.