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Патент USA US3079832

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Sydlihggg
Patented Friar. 5, 19%3
M
vent full compression of the spring, thus making for a
longer life under repeated use.
Other objects and features of advantage of my inven
3,ti7§,823
(EFF-SET EIlECTQR FOR PUNCH DES
Paul R. Ekstrom, 1326 Ciinton Ave, Alameda, Calif.
tion will become apparent from a consideration of the
Filed July 7, 1‘1‘58, Ser. No. 746,889
11 Claims. (er. 83-—111)
following description, and of the drawing forming a part
of this application.
in the drawing:
The present invention relates to devices for displacing
FIGURE 1 is a perspective view of an ejector for
work from a die preparatory to inserting a new piece of
work.
punch dies constructed in accordance with the present
Punch dies are presently used for forming openings in 10 invention and shown partially in cross-section to reveal
internal details.
small ?at metal parts. This part to be punched is posi
FIGURE 2 is a perspective view similar to that of FIG
tioned on a metal die block havin.‘7 openings correspond
URE l but illustrating a modified form of ejector.
ing to the openings which are to be formed in the metal
FIGURE 3 is a cross-sectional view on an enlarged
part. Metal punches of the same size as the die open
ings are forced against the other side of the part to cut
out and remove a slug of metal from the part to be
scale through the air piston of FIGURE 2.
The ejector for a punch die of the present invention
consists essentially of a cylindrical chamber 6 formed
punched.
in a die block 7 and having a cylindrical piston 8 mounte
for axial reciprocation in the chamber 6.
An ejector pin 9 of smaller diameter is carried by the
20
wardly from the die opening.
piston for reciprocating movement therewith and is slida
The metal part is held in place in the desired rela
~bly engaged in a bore 11 which is axially parallel with
tion to the die opening by a metal “gate” secured to the
the chamber 6 and extends to a point underlying a por
upper surface of the die in surrounding relation to the
tion of the Work 12 mounted in the die.
metal part, so as to prevent sidewise movement of the
As here shown, the die block 7 consists of a hardened
part relative to the die.
die member 13 formed with die openings 14 and mounted
With the metal part nesting in the recess formed by
upon a backing block 15. The work 12 is held in posi
the gate and the die, it is rather di?icult to remove after
tion over the die opening 14 by a suitable gate member
the punching operation. Consequently, some type of
17 indicated by the phantom lines in FIGURES l and 2.
ejecting means for pushing the part up out of its nested
Removal of the slug is e?ected through slug ports
which pass through the metal die and are tapered out
Outwardly tapering passages 18 extend through the die
position must be provided.
block 7 from the die opening 14.
Such ejector means may consist of a pin passing
through the die to a point underneath the metal part.
The pin is arranged to push the part up out of its nested
position upon actuation of the pin, as by an air cylinder.
Usually, the air cylinder is formed within the die block
In accordance with the present invention, the ejector
pin 9 and the piston 8 may be eccentric to each other.
This will permit the ejector pin bore 11 to be posi
tioned more closely to the die openings lid than would
be possible where the pin and piston are concentric.
In the form of my invention illustrated in FIGURE 1,
the piston 3 is ofcup-shape, and provides an upstanding
concentric to the pin opening and the air piston and pin
are turned from a single piece of metal.
While the pin is extended by means of air pressure,
furnished to the opposite side of the air piston, it is
commonly retracted by the force of gravity alone.
The described construction creates two serious prob
lems. Firstly, the bores for the pin and piston must be
concentric, and the pin and piston must also be concen
tric. This creates machining problems.
Secondly, when the part is small or there are a num
cylindrical wall 19 and a ?at internal ?oor 21.
40
The ejector pin 9 is provided with an enlarged ?at
tened head 22 slidable over the floor 21 to any desired
degree of eccentricity.
The ejector pin 9 is biased toward its retracted posi
tion by a spring 23 coiled around the pin and com~
pressed between the head 22 and the upper end 24 of the
chamber 6.
ber of openings to be punched, the ejector pin must be
After the punching operation is completed, the ejector
positioned rather close to the die opening. 0f necessity,
pin 9 is moved upwardly by the force of compressed air
the air piston must have a considerably larger diameter
supplied to the lower end of piston 8 through a conduit
than the ejector pin. Due to the concentricity of the
26.
The spring 23 provides a positive return of the pis
pin and piston, it is often di?icult, if not impossible to 50
ton and ejector pin to retracted position when the air
locate the ejector pin.
pressure is removed from conduit 26, thus permitting the
The present invention contemplates an ejector means
ejector to be used in any position.
for punch dies in which the pin and piston may be non—
As a feature of the invention, the spring 23 cannot be
concentric, that is the pin and piston may be eccentric
overstressed. This is accomplished by proportioning the
with relation to each other. »
Walls 19 and the spring 23 so that the upper edge of the
Accordingly, it is a principal object of the present in
wall will contact the upper end 24- of the chamber 6 be
vention to provide a punch die ejector construction in
fore the spring is fully compressed. This is important in
which the ejector pin is mounted on the piston for se
insuring that the spring does not break through many
lective adjustment to any desired degree of eccentricity.
cycles
of operation.
Another object of the present invention is to provide an
The form of ejector illustrated in FIGURE 1 is some
ejector in which the'ejector pin may be positioned close
what limited in that the ejector pin § cannot be adjusted
to the punch die opening without interfering with the
so that its edge coincides with the edge of the piston 8.
slug passages.
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V
i
Thus, the edge of the chamber 6 will always be closer
A still further object of the present invention is to pro
to the slug opening 13 than the ejector pin ? will be.
65
vide an ejector which will operate when the die is in a
position other than horizontal by reason of a positive
displacement of the pin from its retracted to extended
position and return.
Under certain conditions of use it is desirable to locate
the ejector pin at the edge of the chamber. The form of
my invention illustrated in FIGURES 2 and 3 of the
drawing makes such positioning possible.
It is additionally proposed to provide an ejector of the
In this form of the invention, the piston 8 is solid and
spring, and in which the parts are proportioned to pre
upper end. The ejector pin 9 has an enlarged lower end
character described which is retracted by means of a 70 is formed with a diametrically arranged groove 31 in its
3,079,828
3
32 which engages‘ in an’ undercut portion, 33 ofmthe v
groove 31.
The return spring 23is compressed between the lower
end 34 of a bore 36 formed in the piston 8 and the
upper end 24 of the chamber 6.
_
The spring 23 'is proportioned so that .it will not be
fully compressed when the upper end 37-.of the piston
contacts the upper end 24 of the chamber 6.
end formed for sliding engagement in said slot and hav
This ‘will
saidvbore, and spring means on said piston for urging the
' 10
Preferably, a guide sleeve 38 is slidablyam‘ountedin
vbore in said piston for compression between thebottom
of said. bore and the confrontingend.of-saidchamber.
keep the spring'aligne'd with the bore 36. This assures
that the spring cannot become misaligned‘and broken o?
'
In adapting the ejector of the present-invention to a
punch die, the die opening 14 and slug‘ passages 18 are
machined in the die block. The chamber 6‘ is then bored
in ‘the backing block and the conduit 26 installed.
7. An ejector unit as de?ned in claim 6 wherein'said
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tubular member is slidably mountedjin said bore in said
piston, and in surrounding relationtorsaid-spring soas
die face in a suitable position, it being noted that 'it is
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8.v vAn . ejectorv unit as . de?ned. in claim- 7 wherein a
to provide a guidefor retaining -said spring concentric
only necessary for the die' bore to open through the
upper end 24 of the chamber? at any position relative
'
spring is proportioned sothat it will be’ less than fully
compressedwhen saidpiston engages .the end of said
chamber.
The bore 11 for the ejector pinjis then formed in the
to the axis of the chamber.
latter to retracted position in said chamber,
6. An ejector unit’ as de?nedin claim 5 wherein said
spring means includes a helical spring’ mounted in: a
the bore 36 in surrounding relation to' the‘ 'spring23 to
when the air pressure is applied to_the piston. '
said piston having an end formed with a transverse un
dercut slot, an ejector pin having a shoe portion at one
ing its opposite endformed for-(sliding. engagement in
prevent over-stressing of the spring 'andigive it a much
longer life than would otherwise be obtained.
4
5. An ejector unit ,for dies-having. a, cylindricalcham
her and an eccentric ejector bore, comprising a cylin
drical piston formed for reciprocation in‘said chamber,
to said bore in said piston.
9. In a punch.die-machine,l a die block formed with
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a punch hole adapted to cooperate .with-a punch-‘member
With. this construction, no. attempt need be madeto 25 and an outwardly taperedslugjopening extending. from
make the bore 11 concentric with the chamber 6, the ad
said punchhole through~said§die blockgrsaid die block
justable feature of the ejector pin on the piston 8-auto
being formedwith a cylindrical chamber- adapted for se
matically accommodating to. whatever eccentricity is
lective connection to.a sourceof ?uid under pressure and
encountered.
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ejector bore of. smaller diameter than said chamber
From‘the foregoing, it .will bev apparentthatI have 30 an.
and having an axis parallel to and-spaeedlfroni the axis.
provided anv ejector for punch dies whichi'is simple to
of said cylindrical chamberi-wherebysaid bore may- be
machine'and to install and which. is self-accommodating
formed
inclose proximity -to .said punch hole without in-j
to various degrees of eccentricity between the piston and
terference. between. said chamber 'and- said slug opening,v
the ejector pin.
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I .claim:
1. An ejector for a punch. die, having a slug opening
therethrough, comprising a cylindrical chamber formed
in said die-in laterally spaced relation to the slug. opening,
a cylindrical piston mounted for axial reciprocation in
35 said chamber and having an end'facing saidbore formed
with ,a transverseundercut slot,~anleject'orwpin axially re:
ciprocable insaid ejector bore and havinga shoe portion
at one .end . formed for sliding . engagement in said ‘slot
a bore of reduced, diameter formed in said die and hav-'
whereby said ejector pin may be positioned with any?de<
sired degree ofieccentricit'yuto. said piston, and'sprihg
ing an axis in parallel spaced relationto the axis of said
chamber and opening to said chamber and to a point un
means compressed between said piston and the'end of said
derlying a portion of the work to be mounted in said die,
chamber, said spring meansbeingresiliently vcompress
ible.,to,a1lo,w said. piston rise inv said chamber when
a cylindrical piston mounted for axial reciprocation in
said chamber toward and away from said ‘bore, an
ejector pin ‘carried by: said piston for reciprocatingvmove
ment therewith ‘and slidably engaged in s'aidlbor'e; and
means mounting the pin with respect to thefcy'linder to
provide lateral movement of the pin relative to ‘the’ pis
ton, conduit. means in ‘said die adapted for selectively
45
?uid under; pressure. is admitted‘thereto and being su?i-j
ciently- strong to retract said‘ pistonin'said chamber when
they?uid under pressure is released from the chamber.‘
10. A punch die machine asi'de?ned in'claim 9‘wh‘e1'e-V~
in ,said pistontisnformed with, an axially parallel cylingf
drical recess, and said'spring means includes a helical
connecting a sourcehof .?uid under pressure to said 50. spring mounted .in said cylindrical recess and extending
chamber for urging said piston toward said bore where-v
by said pin will eject the work from said die, and means
eifeetive on’ releaseof the actuating pressure to" cause".
therefrom to bearfagainst'. theend of :said‘cham'ber con-w
tainingsaidejector bore}~
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71l.:,A punch die. machineas de?ned jinv claim‘ 10
retrograde .Vrnovementof the ejector unit.
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2. 'An ‘ejector for. a punch die as described in claim 1 55. wherein :a .tubular. member is slidably mounted in ‘said
cylindricalv recessin said piston and in surrounding rela
wherein said pin is ?oatingly mounted on said. piston for
tion
to said spring so as to provide a guide for retaining‘
displacement radially thereof so as to adapt the pin and
said spring. in alignment with'said cylindrical recess, said
piston to chambers'and bores positioned 'with 'ditferent
spring being proportioned so that it- will beless than fully‘
degreeshof relative eccentricity. . '
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compressed.when
said piston engages‘ the‘end ofsaid
3. ,An ejector unit as de?ned in claim‘ 1 wherein said 60 chamber to limit the
stroke of said "ejector:
piston is of cuprshape providing? a ?atinte'rnal mamas
said ejector pin is formed .withauenlarge'd ‘?attenedfhead’
References. Cited .in' the ?leof this-patent _
slidable over said ?oor. i
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4.,An ejevcllorrunitias de?ned in. claim 3 wherein said
retrograde causing means comprises .a"coil‘ spring éiicité 65-. 2,941,530 -' Dewitt"
cling said ‘ejector -'.pin' iandproportionedfforbearing
against said ?attened head and the end'of said chamber
adjacent said borey
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2,118,648
Johnson
22.02.8941. Behle‘r"
mp ____ .._,_May,=,19,:1936
_May 24,;.,193~.s.
. June's-r1940.
2,355,556»
Peterson _
____ Aug-,3, 194s
2,547,394
Broscomb 7___‘,_______,_'_‘_‘., Apr. $111951
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