Improvements in Cutting Shears.
Year: 1890

page_text: Date of Application, 6th May, 1890
Complete Specification Left, 30th Jan., 1891-Accepted, 6th May, 1891
PROVISIONAL SPECIFICATION.
Improvements in Cutting Shears.
A communication from JEAN LACHAUME and JOSEPH PASTEYER, of 142,
Faubourg St. Denis, Paris, Manufacturers.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., do hereby declare the nature of this invention to be as follows:-
The subject of the present invention has been designed with the object of
superseding the present straight bladed shears or cutters used generally for cutting
metal and other materials, and the making with facility of cuts in a straight or curved
line without the necessity for breaks or irregularity. In the usual straight bladed
shears the resistance increases as the blades close together consequent upon the
difference in the angle of the blades and the distance from the centre about which
the blades turn.
In carrying out this invention I prefer to employ circular bladed shears and in
doing so I may use two arms or levers in the usual way one of which carries
preferably two circular cutters while the other arm serves as an operating lever to
drive preferably one of the cutters. In carrying out the invention then I prefer to
so form one of the arms that it shall be adapted to carry say two circular cutters,
and also a second arm or lever which would be pivotted to it. As above explained
it is only necessary to drive one of the cutters and this may be accomplished by forming
upon or connecting with the cutter a ratchet wheel with which engages a spring
controlled pawl pivotted upon what I may call the independent arm, that is the one
which does not carry the cutters. The arms may be kept apart by any suitable
spring device and the action then is that as the arms are compressed by the power
of the hand of the operator and separated by the spring the independent arm
revolves the cutter by means of the pawl and ratchet wheel as will be well
understood.
To control the driven cutter and prevent it from slipping back as the independent
arm returns under the influence of its spring I prefer to employ a form of brake
which will serve both these purposes. This brake may conveniently consist of a
spring controlled plug which would preferably have a V or similar groove so as to
embrace the conical periphery of the cutter: the spring would keep it in contact
with the cutter.
The edges of the cutter would preferably slightly overlap whereby instead of
blunting each other they would tend to sharpen each other and any suitable means
such as a spring or screw may be employed to keep the cutting edges in close
contact.
It will be understood that modifications can be made in this tool without
departing from the spirit of the invention; for example instead of the pawl and
ratchet a suitable strap brake or ball or roller clutch or even gearing could be
employed for the purpose of driving the driven cutter. And similarly instead
of the brake device previously described a pawl and ratchet wheel could be
used or a band brake operating on a suitable drum by the side of the cutter,
or a flat brake operating directly upon the cutter. A short helical spring
secured in the independent arm and resting upon the tail of the pawl is a
convenient way of controlling the pawl and if desired the arms may be kept
apart by means of a spindle socketted or pivotted near the centre of motion of
one arm and passing through an opening in or upon the other arm and preferable
near its outer end and carrying a helical spring which would be compressed
between the arm at one end and a collar on the spindle at the other.
With the arrangement described herein the greater the strain undergone by

page_text: the blades while cutting, the greater tendency they will have to approach one
another and consequently to work out a neater cut; whereas in circular shears
hitherto designed the disposition of the axle of the blades has produced the reverse
effect the greater the effort in cutting the more the blades tend to separate thus
giving rise to irregular cutting.
Dated this 6th day of May 1890.
W. P. THOMPSON & BOULT,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Cutting Shears.
A communication from JEAN LACHAUME and JOSEPH PASTEYER, of 142
Faubourg St. Denis, l'aris, in the Republic of France, Manufacturers.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., do hereby declare the nature of this 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 will be best understood by reference to the accompanying
drawings in which
Fig. is a side view, Fig. 2 an edge view, and Fig. 3 an end view of these
improved shears or cutters.
Fig. 4 shows the position of the two blades provided with a ratchet wheel and
a plug or brake.
In Fig. 5 these two blades are seen in edge view as they come in contact at O.
A is the axle of the lower blade, B is the axle of the upper blade, is the
lower blade, D is the upper blade. E is the ratchet wheel secured to the blade D
by means of a pin E, F is a spring controlled brake, is a pawl operating the
ratchet wheel, H is a spiral spring controling the pawl G, 1 is the main frame
lever, is the pawl lever, K is the spiral spring which pressing upon the collar P
of the spindle tends to keep the two arms IJ apart, L is a diagrammatic
representation of the top of the shears. MN is the imaginary line of the sheet to
he cut and the point of contact of the two blades.
The principle of these shears or cutters mainly consists in the arrangement of
the axis of the ratchet wheel operating the upper blade D. The axle B of the said
blade forms also the axis of the pawl or driving lever J, thus there is practically
only one single arm lover in this device. The brake controlled by the spiral
spring is located within the thickness of the lever and nets upon the upper
blade (Fig. 1). This brake may be made of bronze or any other suitable metal.
The ratchet pawl operates the ratchet wheel E and the upper blade D (Fig. 4)
under the action of the spiral spring 11 (Fig. 1). The blade-carrying axles A
and B are arranged in an oblique plane in relation to the point of contact O of the
blades C and D (Fig. 4), in such a manner that the axle 5 is situated to the right
and the axle A. to the felt of such point of contact 0. The position of the two
cutting blades (which must be corrugated or milled at the edge so as to carry
along the material to be cut) is such that they slightly overlap at Z, that is to say the
distance between the two axles is less than the diameter of ench blade; tho
advantage resulting from this arrangement will be readily realised.
The greater the strain sustained by the blades during the cutting operation the
greater will their tendency be to draw closer to each other and thus to produce a
neat cut. In the circular shears such as have been hitherto devised the symmetrical
arrangements of the blade axles produced exactly the reverse effect viz.; the
greater the strain the greater the tendency of the blades to move further apart, the
result being a jagged and unsightly ent.

page_text: The results obtained by this improved arrangement of shears or cutter with
circular and independent blades may be summed up as follows:-
1st. The strain that has been necessary hitherto to cut sheets of metal direct by
means of shears with straight blades is here avoided.
2nd. The shears cut with the same facility along straight or curved lines no
matter what the outline of the piece to be cut out may be the cut being at all
times neat and without any jags.
3rd. The gradually increasing resistance opposed by the straight blades of the
shears hitherto known as they are brought closer together owing to the initial
angle formed by such straight blades at the beginning of the cut becoming gradually
smaller, is also avoided. It is well known that to overcome this resistance an
effort increasing in the same proportion is necessary as the point to which force is
applied is more and more removed from the axis and therefore diminishes the length
of the operating lever. This it will be seen is a most important advantage of these
circular blades in which the angle of operation is invariable and the distance from
the axis of each of the blades constantly remain the same.
4th. The blades are easily kept in repair and adjusted and they require but
little expense since they can be sharpened in a slow turning lathe without being
removed from their axles and without it being necessary to soften them.
5th. Another advantage lies in the fact that whereas in straight bladed shears
the resistance of the blades to the force applied by the user constantly tends to
move them further apart from each other in a lateral direction thus producing a
jagged cut, the contrary effect is obtained by means of the circular blades, that is
the greater the resistance the greater the tendency of the blades to draw closer to
each other, the result being a perfectly neat cut in the metal sheet or even in paper
the blades being as it were automatically sharpened owing to their friction against
each other which is due to the angle of their axes. The before described improve-
ments may be applied to stationary shears adapted to cut very thick plates.
Having now particularly described and ascertained the nature of the said
invention, as communicated to me by my foreign correspondents, and in what
manner the same is to be performed I declare that what I claim is :-
1. In shears or cutters the mutual independence of the two cutting blades.
2. The operation of one only of the blades by means of a lever fitted with a
ratchet wheel and pawl or other equivalent device and the movement of which may
be either intermittent or continuous.
3. The application of the system of shears substantially as described above
to stationary shears adapted to cut very thick plates.
4. The arrangement of the two blade axles in opposite directions to each other and
in an inclined plane in relation to their point of contact O.
5. The whole arrangement and operation of these improved shears or cutters
substantially as described and for the purpose specified.
Dated this 27th day of January 1891
W. P. THOMPSON & BOULT,
Agents for the Applicant.