EMPORTE-PIECE

DRAW PUNCH

Abrégé anglais

DRAW PUNCH
ABSTRACT:
This invention relates to a draw punch and its
purpose is to punch a hole in sheet metal or the like,
particularly in inaccessible places, such as an elec-
trical outlet box or other terminal outlets. Moreover,
the metal slug that is split into two pieces removed
easier.

Revendications

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A male punch member adapted to be used with
a cooperating female member to remove a slug in two pieces
from a workpiece, comprising a body having an axial bore
extending longitudinally therethrough for receiving means
for moving said body inwardly and outwardly with respect
to the female member, said body having cutting means at
one end thereof, said cutting means being comprised of
a pair of inclined surfaces disposed around said bore and
sloping upwardly in opposite directions from one another,
said inclined surfaces each having a cutting edge on the
entire edge of the outermost portions thereof, each
inclined surface terminating at an uppermost end in a
rib member extending laterally across said surface from
said cutting edge to said bore and upwardly from said
surface at said uppermost end, the rib members together
forming lateral cutting means extending across said one
end of said body except for said bore, whereby the cutting
edges of said outermost portions cut the outer slug
periphery and the rib members cut across the slug to
split it into two pieces when the male member is forced
inwardly of the female member with the workpiece there-
between.
2. A male punch member adapted to be used with
a cooperating female member to remove an annular slug in
two semicircular pieces from a workpiece with a circular
hole therein, comprising a cylindrical body having an axial

Claim 2...continued.
bore extending longitudinally therethrough aligned with
the workpiece hole for receiving means for moving said body
inwardly and outwardly with respect to the female member,
said body having cutting means at one end thereof, said
cutting means being comprised of a pair of identical
helical surfaces sloping upwardly in opposite directions
from one another with each surface overlying a semicircular
portion of said one end, said helical surfaces each having
a cutting edge on the entire edge of the outermost portions
thereof and each terminating at an uppermost end in a rib
member extending radially across said surface from said
cutting edge to said bore in diametrically opposed relation
to the other rib member and upwardly from said surface at
said uppermost end, the rib members forming diametrical
cutting means across said one end of said body except for
said bore, whereby the cutting edges together cut a circular
outer slug periphery and the rib members cut across the
slug diameter to split the slug into two annular, semi-
circular pieces when the male member is forced inwardly
of the female member with the workpiece therebetween.

Description

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This invention relates to a novel punch to be
used with a draw punch for metal removal. Prior art,
such as disclosed in U.S. Patent 2,237,069 shows a draw
punch having a die with a bolt axially aligned and
threadedly engaged with a cutting head and a nut, such
tha-t as the nut is turned, the cutting head is uryed to
cut a slug of rnetal that is the same size as the inner
diame-ter of the recessed portion of the die. Moreover,
United States Patents 1,817,223, 2,221,904 and 3,269,011
show a typical metal punch and die means.
According to the present invention there is
provided a male punch member adapted to be used with
a cooperating female member to remove a slug in two pieces
from a work piece, the male punch member having a body
with an axial bore extending longitudinally therethrough
for receiving means for moving the body inwardly and
outwardly with respect to the female member. The body
has cutting means at one end thereof, the cutting means
being comprised of a pair of inclined surfaces disposed
around the bore and sloping upwardly in opposite directions
from one another. The inclined surfaces each have a
cutting edge on the entire edge of the outermost portions
thereof, each inclined surface termina-ting at an uppermost
end in a rib member extending laterally across the surface
from the cutting edge to the bore and upwardly from the
surface at the uppermost end. The rib members together
~- form lateral cu-ttiny means extending across the one end of
,
the body except for thc bore so that the cutting edges of
the outermost portions cut the outer slug periphery and

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the rib members cut across ~he slug to slit it into two
pieces when the male member is forced inwardly of the
female member with the work piece therebetween.
The unique design of the punch or cutting head
provides easier removal of the slugs in that the slug
is split into two pieces.
BRIEF DESCRIPTION OF THE DRAWINGS
Eiy. 1 is a top view of the punch or cutting head;
Fig. 2 is a general side elevational view of -the
punch or cutter head;
Fig. 3 is a general side oblique view of the
punch, shown in the direction of the arrow --3, in Figure 2;
Fig~ 4 is another general side view of the punch,
shown in the direction of the arrow --4 in Figure 2.
DESCRIPTION OF T~E INVENTION
In the draw punch or cutter head illustrated in
the drawing and described in detail herein, the die that
is mated with the cutting head is not unique, in that it
is a typical female die comprising a cylinder with one end
closed and a recess comprising an inner diameter extending
throughout almost -the length of the die. The closed end
of the cylindrical die includes a bore which is aligned
with the threaded bore of the cutting head or punch. In
particular, the invention relates to a cut-ting head 10,
typically called a male punch, having a threaded bore 15
axially aligned throughout its longitudinal length. The
outer diameter 20 of the cutting head 10 is adap-ted -to fit
the inner diameter of a female die, not shown. The cutting
head 10 comprises a plurality of helical or inclined

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surfaces 25, 25' with respect to the top surface of rib
members 30 and 30l, as clearly shown in Fig. 2 and Fig. 4.
Each inclined surface 25, 25' covers the semi-circular
portion of the cutting head 10, and is symmetrical as
viewed from the top of the tool in Eig. 1. In other words
one inclined surface 25 is one-half of a single pitch
screw or thread and the other inclined surface 25' is
also one-half of a sinyle pitch screw or thread. Each
uppermost portion of the inclined surfaces 2S, 25l end at
the ribs 30, 30' respectively. The diameter of ribs 30
and 30' is the same diametral size as the cutting head,
and is disjoined at the center by the diameter of bore 15.
In other words, the ribs 30 and 30l extend diametrically
from one edge 45 of the cutting head 10 to the other edge
45', except for the bore 15. Each rib 30, 30' has two
uppermost lateral faces 35 and 40, 40' respectively.
Lateral face 35 meets the uppermost radius juncture 47 of
the inclined surface 25 whereas lateral face 40 meets
~the lowermost radius juncture 471 of inclined surface 25, 25l.
The preferred embodiment of the drawing shows a pair of
inclined surfaces 25 and rib 30, 30' at the radius juncture
47, 471 of each inclined surface, for the purpose to be
described herein.
In operation, the male punch is placed opposite
the female die member (not shown) with a metallic member
to be cut in between both punch members. A bolt Inot shown)
is inserted through the bore of the female die (not shown)
and through the hole of the metallic member previously
drilled therethrough to allow such bolt to be inserted

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therein and threaded onto the threaded portion 15 of the
punch die lO. A nut or other device is then adapted to
squeeze together the male punch or cutting head and the
female die. As the male punch is progressively moved
against the metal, edge 45 cuts the diametral hole, and
the diametral ribs 30, 30' separating each inclined
surface 25, 25' is adapted to cu-t the metallic slug into
two pieces. It is therefore apparent that the metallic
slug that is cut out of the metal is split into two pieces
by virtue of the ribs 30, 30' that is at the uppermost
radius juncture 47 of the inclined or helical surfaces
25, 25' and the diameter of the metallic slug is cut by
the edge 45, 45'. The radius juncture 47 is formed between
the inclined surfaces 25, 25' and the lateral faces 40, 40'
to provide strength and rigidity to the punchO
A preferred embodiment of the present invention
has been described herein and illustrated in the accompanying
drawings by way of example. However, it is to be understood
that numerous modifications thereof may be made without
departing from the broad spirit and scope of the invention
as defined in the appended claims.