Improvements in Punches for Stamping Rivet; Bolt, and like Holes in Metal' and' other' Material.
Year: 1894

page_text: The decision of the Comptroller-General, of the 19th day of July 1895, allowed,
.an. Amendment of this
under Section 18 of the Patents,,&c. Act, 1883, .1
Specification
Date of Application, 19th: Oct., 1894-Accepted; 16th Feb., 1895
COMPLETE SPECIFICATION' (AMENDED).
Improvements in Punches for Stamping Rivet; Bolt, and like Holes
in Metal' and' other' Material.
We, HARRY RIGBY of 8 Montague Avenue, Brockley, S.E. Engineer and
RICHARD KNIGHTS, of 6, Mornington Villas, Wanstead Park; Essex, Engineer,
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 relates to an improved punch for stamping rivet, bolt and other
holes from metal or other material, and is intended to provide an arrangement
which will stamp the hole and will smooth the sides finishing it at oue operation.
When such holes are stamped by the ordinary punches, they require to be
broached or cleaned out, about one eighth of an inch being commonly cut away,
in order to make the sides parallel and smooth, as the punch leaves them rough
and uneven. This is a very tedious and expensive process as several operations
are required for each hole. With our arrangement the cleaning out or broaching
of the hole is entirely dispensed with, the sides being left perfectly parallel and
smooth. We effect this purpose by a peculiar formation of the punch.
a short distance above the cutting edge of the punch instead of making the sides
plain, we form a second cutting edge or shoulder of slightly larger diameter than
the lower or ordinary cutting edge. The action of the device is as follows-
At
After the ordinary cutting edge of the punch has entered the metal and
has partially or completely stamped out the punching, the upper edge, which as
above mentioned is larger than the lower, comes into operation, and cuts a thin
annular piece of metal from the hole, enlarging it to the required size, and making
the sides perfectly parallel and smooth.
In order that the invention may be more clearly understood, reference is had to
the accompanying sheet of drawings, in which Fig. 1 shows our improved punch in
side elevation, Fig. 2 shows it in operation, Fig. 3 is a vertical section of its end,
and Fig. 4 illustrates a slightly modified form.
The end A is formed with the ordinary cutting edge a at its lower extremity.
At a short distance above this edge, the distance varying with the size of the punch
and the thickness of the plates it is required to stamp, is formed the shoulder B
having a sharp cutting edge, the shoulder being wider than the lower edge. The
portion 6 of the punch above this shoulder is made sloping as in the ordinary punch
to give proper clearance. As shown in Fig. 2 the plate C is placed on the die D
and the punch is forced through the metal in the usual manner, stamping out the
punching c which falls through the hole of the die. Immediately following this
piece the cutting edge B cuts out the ring of metal c' cleaning out the hole.
1

page_text: The modification shown in Fig. 4 has a precisely similar action, the only
difference being that instead of forming the sides b tapering from the edge B, a
small part 6 immediately above the edge B is made vertical or with parallel sides,
giving greater strength to the cutting edge, which has of course to bear the whole
strain of cutting out the ring c¹.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is.
-
(1.) In a punch for stamping rivet and like holes, forming a shoulder at a short
distance from the extremity, having a cutting edge slightly larger in diameter than
the ordinary cutting edge, and adapted to out at one operation-the-rough-hole and
an annular piece, trueing or finishing the said hole, substantially as and for the
purposes specified.
(2) 1. The improved punch, formed with an additional cutting edge of larger
diameter at a short distance from the extremity, for finishing the roughly stamped
hole formed by the ordinary cutting edge, in combination with a tapering stem
substantially as described and shown in Figs. 1, 2 and 3 of the drawings.
(3.) 2. The improved punch for stamping rivet and like holes, formed with a second
cutting edge at a short distance above the extremity and of larger diameter than
the ordinary edge, the tapering stem band the vertical portion section b¹ immediately
above the shoulder, substantially as described and shown in Fig. 4 of the drawings.
Dated this 19th day of October 1894.
GEO. H. RAYNER,
37, Chancery Lane, London, W.C., Agent for the Applicants.