IMPROVEMENTS IN MACHINES FOR PUNCHING AND SHEARING METALS, APPLICABLE ALSO FOR APPLYING PRESSURE IN OTHER CASES
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the
Office of the Commissioners of Patents on the 31st July 1877. A communica-
tion from abroad by David Brickner, of New York City, in the County and
State of New York, United States of America.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN MACHINES FOR PUNCHING AND SHEARING
METALS, APPLICABLE ALSO FOR APPLYING PRESSURE IN OTHER CASES." [A com-
munication from abroad by David Brickner, of New York City, in the County and
State of New York, United States of America.]
This Invention relates to a machine for punching and shearing metals, which is
designed to be operated by hand or by means of a treadle; and it consists mainly
in the combination of a heavily weighted pendulum with the levers and moving
parts of a shearing and punching machine, whereby a powerful and effective action
of the shears or punch are secured by the expenditure of a small amount of force.
The Invention also consists in a novel combination of levers and other parts for
operating the shears and punch, as herein-after more fully described.
According to this Invention the machine has a longitudinally slotted bed, on the
forward end of which is mounted a divided standard, upon the upper front end of
which is formed the stationary shear blade. The working blade of the shears is
arranged to rock upon a fixed pin or fulcrum which passes through the standard,
and along which the blade may be adjusted by means of set screws. These set
screws are arranged in both sides of the standard, and bear against washers in
opposite sides of the blade at suitable points around the fixed pin or fulcrum. By
means of these set screws the upper or working shear blade may be adjusted to cut
more or less close to the lower or stationary blade to adapt the machine to shearing
thin or thick work, and to provide for wear. A pendent lever, having its fulcrum
on braces connecting the standard with the bed of the machine, support on the
upper and shorter arm a toothed sector, gearing with another toothed sector on the
rear end of a connecting rod or bar, which is jointed at its forward end to the
moveable shear blade. Links at the pivots of the toothed sectors serve to connect
the lever with the rod, but instead of links coil springs may be employed to draw
the lever and rod together. The lower and longer arın of the lever is connected by

page_text: a rod with a heavily weighted pendulum or swinging balance lever, oscillating on a
fulcrum or pivot which is located at about the middle of its length, and carrying
weights on both its upper and lower arm, or upon the lower arm only. The lower
weight should be the heavier one, and it may be varied to suit the work to be done
by the machine. The lever is oscillated to give the required motion to the shear
blade, either by hand through an arm or handle applied to the lower end of the
pendent lever, or by foot, through a treadle connected with the said lever. The
punch is operated against one or more springs of any suitable description by a cam
formed on the under side of the moveable shear blade. This cam works against a
roller journalled in the upper end of the punch follower. The punch works through
a guide secured to the machine standard, and is arranged to operate in connection
with a lower female die.
The momentum of the pendulum as it is oscillated gives a powerful and effective
action to the punch or shears similar to that of a drop press. In a punching machine
of this description two or more blows in succession may be readily given to punch
one and the same hole in metal of considerable thickness.
A stripper is provided consisting of a bar, which is apertured to receive the punch,
and bent at right angles, and connected with a foot lever. By operating the stripper
by means of a separate lever the power that would be absorbed by drawing the
punch out of the metal is saved.
For light work the upper weight on the lever may be removed, thereby reducing
the momentum, and also the labour of working the machine. Said lever may, if
desired, be made of considerable length, so as to project down into and work within
a pit, and the lower weight may be shifted closer to or farther from the pivot of the
lever as circumstances may require.
I do not limit or confine my improvement to the punching and shearing of metals,
as it may be applied with equal advantage to many other purposes where a great
temporary pressure is required.