A New or Improved Method of and Apparatus for Punching and Heating Metal.
Year: 1893

page_text: COMPLETE SPECIFICATION.
A New or Improved Method of and Apparatus for Punching and
Heating Metal.
A communication by CHARLES LEWIS COFFIN, of 980, Jefferson Avenue,
Detroit, in the County of Wayne and State of Michigan, United States of
America, Chemist.
1, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool, and 6, Bank Street,
Manchester both in the County of Lancaster and 323 High Holborn in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
This invention consists in an improved method of and apparatus for punching
metal, hereinafter fully described and claimed.
In the drawings—
Figure 1 is a perspective of the machine, and Figure 1A is an elevation of the
heating and punching mechanism proper with the machine shown behind in dotted
lines;
Figure 2 is an enlarged central view of the movable carbon holder, and carbon
partly in section, as applied to heating by incandescence;
Figures 2, 3 and 4 are diagrammatic views of the different stages of the operation
where the arc is used for heating.
The principle of the invention consists in electrically heating the next point in
the metal where a hole is to be punched, while the punch is performing its work.
This heating may be done either by applying an are to the point to be heated, or
by passing a heating current through said point, the apparatus shown in Figures 1
and 1 being intended for passing a heating current through the point to be
punched, while the apparatus and diagrams of the other figure refer to heating by
forming a voltaic arc at the point to be heated.
A, represents a frame of a machine consisting of suitable legs and table to
support the material to be punched and a female die for punching, and a gooseneck
to carry the eccentric or toggle-joint mechanism for operating the punch, all of
which are so well known that detailed descriptions thereof are not considered
necessary.
B, represents a driving pulley mounted on a shaft journaled in the upper part of.
frame A, and carrying a crank or eccentric D', by which punch holder C and male
punch Care operated, the punch holder running through a suitable guide as
indicated in the drawing. On the end of the same shaft which operates punch
holder C is fixed an eccentric D, the motions of which vary in accordance with
that of the two methods of heating above named which is proposed to be adopted.
As shown in Figures 1 and 1^, the eccentric D has on it an ordinary eccentric
strap, to which is pivoted the upper end of pitman D'. The lower end of this
pitman is secured in any suitable way as by a set screw to a block of insulating
material I, to which is also secured a carbon holder E. For heating without the
arc, the carbon E' is slipped loosely into carbon holder E, and is pressed down by
a light spring K, whose tension may be regulated by a block J', provided with a
screw threaded bolt and nut J. L represents a clamp secured to the upper end of
carbon E and projecting through a slot in carbon holder E, and to this clamp is
attached one end of a conductor, by which the carbon E is connected by one
terminal of a generator of electricity. G represents a clamp secured to the frame A
of the machine through the medium of a block of insulating material 1, and
provided with a set screw G! by which a carbon F may be held in said clamp at

page_text: any desired height, and this clamp G is connected by a conductor with the other
terminal of a generator of electricity. H represents the material to be punched,
lying on the bed of the machine; as shown in Figure 1, it is fed from left to right,
the punch C¹ being at the right of the carbon E
The operation of this part of the invention is as follows:-
A current being admitted to the conductors x and y and the pulley B being set
in motion, the rotation of its shaft, by means of the eccentric or other mechanism B',
forces punch C¹ down into the female die adapted to receive it, and in doing which
the punch passes through material H, if that be in position. As the punch descends,
the eccentric D also forces carbon holder E downward until carbon E' comes in
contact with material H, and then, as carbon holder E descends, the carbon E
rises therein against the resistance of spring K, if such spring be used, thus
maintaining contact between carbon E' and the material H. This establishes a
circuit through conductor a, carbon E', material H, carbon F which is in contact
with the underside of material H, clamp G and conductor y back to the generator,
thus heating that point of material H with which carbon E is in contact through
the passing of a heating current therethrough. As the punch C' rises, the
carbon E will eventually be raised off from material H, thus breaking the circuit.
The material H is now fed to the right, the proper distance to bring the point
just heated by carbon E¹ beneath the punch C, when the next stroke of the
machine will punch a hole at said heated spot and simultaneously heat another spot
in the manner just described. If it be desired to use the arc for heating instead of
a beating current, the arrangement is substantially the same, with the single
exception that the eccentric D is so arranged as to first bring the carbon E¹ into
contact with the material H and thus complete a circuit, then slightly lift said
carbon from the material to establish an arc, as shown in Figures 2 and 3, and,
finally, withdraw said carbon to break the arc when the punch Crises. This may
be done in a number of ways known to skilled mechanics, the one illustrated being
to cause the eccentric D to act against a pin D3 set in pitman D' and so form said
eccentric or cam D that it will first lower carbon E' into contact with material H
as the punch C' descends, as shown in Figure 2, and will then raise it slightly to
form the arc, as shown in Figure 3, while the punch C¹ continues to descend, and
finally will raise the carbon away from the material as shown in Figure 4, when
the punch C is lifted. It is evident that the cam eccentric D may be so pro-
portioned in either case as to give a comparatively long period of contact or such
proximity as to form the arc between the carbon and the material and then retract
the carbon with a quick motion when the punch C¹ is nearly at the upper end of
its stroke.
This method enables one to punch metal with comparatively little power and
with little wear on the punch, and obtain the very great advantage that the
strength of the metal around the hole punched is not reduced nearly as much as it
18 when the metal is punched cold, the strength approximating very closely to the
strength of drilled holes.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1. The herein described mode of punching and heating metal, consisting in
simultaneously punching a hole and electrically heating the point at which the next
hole is to be punched.
2. In an apparatus for punching metal, the combination with a press and punch
carried thereby, of a carbon adapted to make contact with the underside of the
Inaterial, a carbon above the material actuated by the punching mechanism to and
from the material to be punched, and connections between said carbons and the
terminals of a source of electric energy, substantially as shown and described.
3. In combination with a punching press, a carbon carried on said press and flush
with the bed thereof, a connection between said carbon and one terminal of a

page_text: generator of electricity, another carbon carried on the mechanism which actuates
the punch, and connected with the other terminal of said electric generator and
means substantially such as described for giving said upper carbon a motion to and
from the material to be punched co-extensive with but varying from the motion of
the punch, substantially as shown and described.
Dated this 19th day of June 1803
WM. P. THOMPSON & Co.,
Agents for the Applicant.