IMPROVEMENTS IN SHEARS
Year: 1880

page_text: "
PROVISIONAL SPECIFICATION left by the said David Ward and Thomas
Birkhead at the Office of the Commissioners of Patents on the 12th January
1880.
DAVID WARD and THOMAS BIRKHEAD, both of Sheffield, in the County of York.
'IMPROVEMENTS IN SHEARS."
This Invention relates to improvements in shears, and more particular to sheep
shears, but it is also applicable to other similar shears, and it has for its objects,―
Firstly. The prevention of the shear blades being forced apart, and thus allowing
the material under operation to pass through them without being cut.
Secondly. To counteract the tendency of shear blades that have been sprung
apart for the purpose of whetting or sharpening to pass each other on the wrong
sides instead of keeping on the cutting sides.
Thirdly. To enable the blades of shears to be opened sufficiently wide apart
without stretching the bow, and consequently damaging its elasticity, to allow the
blades to be conveniently sharpened, and these desirable objects we attain in the
following manner :-A piece of curved wire or rod is secured to the inside of one
of the shanks of the shears by means of a screw and nut, and the other end of the
wire or rod is passed through a suitable hole in the opposite shank, and is
sufficiently long that the shears may be opened to their full extent. The end of the
wire or rod is either bent or provided with a head to prevent the blades being
forced apart or out of contact at the heel of the blade, which is often the case with
shears that have been sprung wide apart for sharpening.
To allow the blades of shears to be opened to a more convenient position for
sharpening than is usual, we make one of the blades and its shank separate from
the other one, which is attached to the bow, and we attach them together by a
kind of joint so that the two blades may be separated to about an angle of ninety
degrees, or the fourth part of a circle. To secure the blade in the proper cutting
position a thumb screw passing through the two parts of the joint is the most
convenient method, although we do not bind ourselves to that particular
arrangement.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said David Ward and Thomas Birkhead in the Great Seal Patent Office
on the 12th July 1880.
DAVID WARD and THOMAS BIRKHEAD, both of Sheffield, in the County of York.
"IMPROVEMENTS IN SHEARS."
Our said Invention relates to improvements in shears, more particularly sheep
shears, but it is also applicable to other similar shears, and it has for its objects,-
Firstly. The prevention of the shear blades being forced apart laterally, whereby
the material under operation is liable to pass between the sides of the said blades
without being cut.
Secondly. To counteract the tendency of the shear blades to overlap on the
wrong sides after having been sprung apart for the purpose of whetting or
sharpening.
Thirdly. To enable the shear blades to be separated sufficiently from each other
without stretching the bow when the said blades required to be sharpened.
And in order that our said Invention may be fully understood we shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the several Figures on the annexed Sheet of Drawings, the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 of the accompanying Drawing represents a sectional elevation of a
portion of a pair of shears constructed according to one part of our said Invention.
Figure 2 is an elevation of a portion of a pair of shears constructed according to
another part of our said Invention, and Figure 3 is a side elevation of the same
shewing in dotted lines the position of one of the blades when turned aside for the
operation of sharpening, as hereinafter described.
A represents the blades of the shears; B, the shanks of the same; and C, the
bow.
In carrying out the first part of our said Invention, which is illustrated in
Figure 1, one of the shanks B of the blades has rigidly attached to its inner surface
a wire or rod D, one extremity of which is formed square, so as to fit into a
corresponding shaped hole in the shank, and is held securely therein by a nut and
screw, whilst the stem of the rod extends through a slot 6 in the opposite shank, the
free extremity of the rod being formed with a head d, which prevents the shanks
of the blades from springing apart beyond a certain limit.
The length of the rod D is such that the blades A are always kept in contact at
the heel or that part marked a, whereby the blades are prevented from crossing
each other on the wrong side, as is frequently the case with shears which have
been sprung wide apart for sharpening.
It is preferred to make the rod bent or curved in such a manner that it shall act
as a spring, and tend to keep the blades in close side contact, whereby the liability
of the material under operation passing between the sides of the blades is
obviated.
In carrying out the second part of our said Invention, which is illustrated in
Figures 2 and 3, one of the blades A of the shears has its shank B jointed to the
bow C. A rivet E passes through the flat pieces b', c, formed at the extremities of
the shank and bow respectively, by which the said shank and bow are connected
together, and upon which the shank with its blade is capable of turning. A thumb
screw F, situate as shewn in the Drawing, is provided by which the bow and shank
are rigidly held together when the shears are in operation. By this arrangement
the necessity for stretching the bow, and consequently damaging its elasticity, when
the blades have to be separated for the purpose of being sharpened is avoided.
When the blades require sharpening, the thumb screw is unscrewed and
disengaged from the bow piece, and the blade upon the centre or rivet E is turned

page_text: aside out of the way of the opposite blade into the position indicated by the dotted
lines in Figure 3.
In lieu of forming one of the blades of the shears in one with the bow, and the
other as a separate part, both blades may be jointed, in which case the bow would
be a separate piece.
The two parts of our said Invention may be used either separately, as hereinbefore
described and illustrated in the accompanying Drawing, or they may be employed
in combination in the construction of a pair of shears.
Having now described and particularly ascertained the nature of our said
Invention, and the manner in which the same is or may be used or carried into
effect, we would observe in conclusion that what we consider to be novel and
original, and therefore claim as the Invention secured to us by the herein before in
part recited Letters Patent is,-
.
First. The employment in shears of a wire or rod D, substantially as and for the
purpose hereinbefore described.
Secondly. The employment in shears of a jointed blade or blades, substantially
in the manner and for the purpose herein before described.
Thirdly. The combination in a pair of shears of a jointed blade or blades and a
wire or rod D, substantially as herein before described.
In witness whereof, we, the said David Ward and Thomas Birkhead, have
to this our Specification set our hands and seals, the Ninth day of July,
One thousand eight hundred and eighty.
DAVID WARD.
(L.S.)
THOMAS BIRKHEAD. (L.S.)