Note: Descriptions are shown in the official language in which they were submitted.
7~
BACKGRO~ND OF THE INVENTION
_ _ __
This in~ention relates to die casting machines and
in particular to a system including a die casting machine
of the balanced, dual movement type that incorporates two
pairs of space;d, parallel cylinder assemblies e~ch of which
support a mold half, the pistonu of the cylinders being
secured ~o the machine frame and the cylinders moving thereon.
In a conventional die casting machine a rame i5
provided and a fixed or stationary plate upon whic~ on~-half
of the mold for making the part is mounted on the frame. The
other half of the mold is mounted upon a moving plate which
allows the cast part to fall out of the m~chine when in ~he
open position and the moving plate is clamped shut with
sufficient force to contain the molten metal while the mold
is being ~illed. In operation, the part ~eparates from the
half mold on the fixed plate (the cover half~ an~ i8 retained
on the half mold of the moving plate (the eiector half) as it
moves open following solidification of the molten metal which
was injected into the mold cavity. The part which was
2Q retained on the moving or ejector half of the mold mu6t then
be ejected from it to fall out or be transferred out of the
machine. The one-sided motion described above i5 one of the
major causes for the various and complicated types of ~to-
matic part-transfer mechanisms associated with conventicnal
casting machines which have been retrofitted with ~ome sort
of part-trnnsfer. The ~ame problem then ari~es ~8 the part i~
indexed ~o a secondary opera~ion ~uch as tri~ming wherein a
similar one-sided m~hine is used. The part transfer c~rr~er
is required to have both an indexin~ fun~tion and a la~eral
mov~ment to match the p~ate closln~ and opening stroke ~s the
part is ~rought lnto ~ fixed position for ~he desired ~peration.
Thls con~ntivnal form of ~achine was gre~tly improved
. .
upon by the machine shown in the U.S. Patent to Perrella,
4, 013,116 which issued on ~arch 22, 1977. This machine is
much simpl~r than conventisnal devices in that the part was
cast, indexed and removed from the machine for trimming without
~ny lateral mo~ement of the part. During processing the par~
i9 in a fixed plane and i~ txansferred in that plane. -The .
casting machine has balanced forces in which both plates and
mold halves or dies are moved equal distances to and from the
pArt plane and this balanced mov~ment of lla65 can~els ou~
the normal shock of starting and s~opping heavy plates and
tools, e~ualizes thermal expansion di~ferences and automatically
centers load deflections.
SU~D~ARY OF THE INVENTION
The balanced, centred, single plane machine principle
of U.S. Patent 4,013,116 is the basis for the present invention
but on which numerous improvements and additional features
have been added such as a cable conveyor of low mass ~nd simple
design for transfer of the parts ou~ of ~he machine, a simple
part carrier finger at the center line of the mold, metal-
injection on the mold pPrting line, one half the normal strokefor plate m~vement and thus one half the non-productive time
for machine opening and closure, a top core pin position
on the mold parting line to stabilize the part positi~n during
mold-opening and eliminate the need ~or ejector pins on ~ome
types of parts, opportunity to add internal cores in both mold
hal~es, and automatic loading c}earanoe during Ln~tallation of
the mold and trim dies. The ma~hine of ~he present invention
is designed a~ a total integrated casting unit which will
delivex a quality part c~st and tr~mmed automatically ~t ~ pre~nt
rate of production. As ~uch it i one unit incorpor~t~ng
numerous ~eatures.
The main ~chine consi~s of a fr~me, ~old mounting
plates and hydraulic closing and opening c~linders havin~ a
simple deceleration system to eliminate closing shock. A
standard and uniform ~sic mold con~igur~tion is pr~vided and
is adaptable to a large variety of part styles and is of
pre-determined registry in the machine plates so as to
eliminate mold miss-match because of thermal expansion or
poor die set practices. Metal-injection of the machine is
provided with an infinitely varia~le control capable of
presetting to any desired speed or pressure, together with a
self-contained molten metal supply with electric resistance
heaters therein.
A self contained hydraulic power system is incor-
porated, using fire-resistant fluido Provision is made to
pre-heat the molds prior to the first shot. The machine
features a self-contained heat unit for cooling the molds
and eliminating lime deposits in the cooling passages all of
which is automatically connected to the mold during
installation withoùt hoses or pipes. A cable transfer
conveyor is also provided to carry the part on a finger to
other secondary operations with adequate time before trimming
for natural non-distortion cooling of the part prior to
trimming, together with a complementary trim machine and
basic trim die designs to push the part through the die to
a carry-away conveyor.
In accordance with a broad aspect, the invention
relates to a metal injection system for a die casting machine
including means for injecting metal on the parting line of dies
in said machine means for subsequent drainage of unsolidified
metal from a runner in the dies; and said metal injection
system comprising a steel body having a pair of cylinders
'.~
7~
including a first cylinder having a pressure intensifying
piston therein for a) filling a shot chamber with molten metal
from supply thereof and b) efecting an injection of said ~etal
from said chamber into dies of a die casting machine; and a
second cylinder including a selector ~Talve adapted in one
position to a) open a passageway .~rom said metal supply to the
chamber of the intensifier while b) simultaneously closing off
the passageway from the chamber to a nozzle of the unit and in
another position to c) close of~ the metal suppl~ passageway
and simultaneously open the chamber-to-nozzle passagewa~.
The abo~e and other ~eatures will be understood
from the following disclosure and accompanying drawings
wherein:
Figure 1 is a plan view of the die casting machine;
Figure 2 is a cross-sectional view of the machine
taken along the line 2-2 of Figure li
Figure 3 is a schematic, cross-sectional view taken
along the line 3-3 of Figure 2;
Figure 4 is a schematic layout of the heat transfer
system for cooling the dies of the machine;
Figure 5 is a cross sec~ional view of the metal
supply pot and heating means;
Figures 6 and 7 are schematic illustrations of the
metal injection,
Figures 8a and 8b are cross sectional ~Tiews of the
metal injection unit;
Figure 9 ~s an enlarged cros~; ~ectional view sf
the valve mechanism of the injection unit;
Figure 10 is a side ele~ration view of the injection
unit;
Figure 11 are elevation and end view of the ~wan's
neck joint;
Figur~3 12 is a cross sectional view ~ken along the
line 12-12 of figure 8a.
Figures 13 and 14 are concept illustrations of the
nozzle arrangement of the invention;
Figures 15 and 16 are views of a preferred nozzle
arrangement;
Figure 17 is an elevation view of a typical mold
cavity; ~-
Figure 18 is a cross se::tional view of the rotary
e j ection mechani~m;
Figure 19 illustrates the cam and ~ollower of the
rotary eje~tion;
Figure 20 a, b and c show various po~itions of the
rotary e j ection during its operation;
Figure 21 i8 a cross ~ectional view showing the ;~
core pin withdrawal system; .;
Figure 22 is an elevation view of one end o~ the
part transfer ~echanism;
Figure 23 is ~n elevation ~riew of another end of the
transfer mechanism;
Figure 24 is a ~ros~ section~l view talcen along ~he
line 2 4- 2 4 of F lgure 2 3; :
Figure 25 i~ a sectional view of the transfer ~nger;
F~gure 2S ls ~ cro~ sectis3nal vi~w tAkea als3ng the
line 26~ 26 of F~ g~ 22;
Figure 27 i~ a ~ectional view of the kicker mechanism;
~ igure 28 is an elevation view partly ~n cro~s ~ection
of the trimming apparatus; and
Figure 29 iB a cross sectional view taken along the
line 29-29 of Figure 28.
Figure 30 i~ an elevation view of a cast part as it
enters the ~rimming appara~us; :.
Figure 31 i~ a plan view of ~ punch of the tr~mming
apparatus, ~nd
Figure 32 is a sectional ~iew of the punch and die of
~he trlmmer.
GENERAL DESCRIPTION
Referring to Figures 1-3 a die casting system According
to the invention includes a die casting machi~e 10 ~a~ing a
frame 12 with two pairs of ~paced, parallel cylinder assemblies
14, 16 mounted thereon. Each pair of assemblies 14 ~upport
a mold half 18, as shown in Figure 3, and is opposed to the
other pair of assemblies 16 which carries the other mold half
20. As seen best in the general layout o~ Figure 3, each
cylinder assembly of ench pair comprises a stationary piston
22 secured to the frame 12, a piston ~haft 24 secured
coaxially at one end to, and axially aligne~ with the piston , '
22, the shaft 24 extending acr~ss the centre of the machine .
to a connection at it8 other end ~ith an oppo~-~ed piston 26 :
of the other cylinder ~ssembly 16.
As illustr~ted in Figure 3, each cylinder a~sembly
14, 16 compri~es ~ylinder~ 28, 30 re~pectively mo~n~ed Dn
the piston~ 22, 26 and sha~t~ 24 for reciprocal mo~ement of
the ~ylinders ther~on $n respon~e to hydr~ulic fluid ~njected
on ~he crown or ~kirt end~ 62, 64 re~pe~tively ~f the pi~ton~
where~y the a~em~lie~ 14, 16 and their a~soc~ated mold hal~es
are moved ~o open ~x closed (~8 ~how~) po~ition~.
~ 6 -
A more detailed description of the bas~c concept of the
machine 10 may be had from the disclosure of U.S. Patent
4,013,~16.
Turning to Figure 1, a plan view of the machine 10
shows the mold clamping cylinders 14, 16, platens 32, die -
~eparation and ejection cylinders 34, interference blocks 36
- 6A
.
for preventing acciden~al cylinder ~ovement and the drive
means 38 for the transfer mechani~m.
Figure 2 illustrates the in~ector assembly 40
comprising the furnace 42 goosenec~ 44 with sho~ and selector
valves 46 48; and shot valve locking system 50. Nozzle 5~
directs the zinc shot into the mold 54 to provide a casting 56
that is cast onto a carrier finger 58 on the ~ransfer mechani~m
60 that transports the cast par~ to a trimming ~tation.
A die casting machine requires only ~ small, nominal
force to advance the molds to their closed position shown
in Figure 3 but this must be followed by a strong clamping
force to retain high internal pres~ures devPloped in ~he
mold when the casting metal is injected therein. Therefore,
a cylinder large enough to clamp the die would require an
excess volume to fill it during the closing stroke. As seen
in Fi~ures 1-3, the machine of the pre~ent invention is of
the two-tie bar type with e~ch end o~ the two shaft~ 24
extending through the hollow centre of the two stationary
pistons 22, 26 on each side of the machine. As ~een in
Figure 3, the pistons have rod extensions 22a and 26a on
their skirt ends but the extensions are of a smaller di~eter
than the crown ends o~ the pistons and therefore form a
slightly different pressure area at each end o~ the surround-
ing cylinders ~8t 30 which are the moving members and which
are integral with the machine platen~ 32 on each side of ~he
machine centre. ~ccordingly, ~y pres~urizing both the ~rown
end 62 and ~kirt end 64 o~ each oylinder and providing an
internal flow pass~ge from the smaller pre6sure area 64 to
the larger 62, the flu~d vol~me th~t is required for a ~yl~nder
stroke $n one direction is ~nly the difference between the
two areas 62, 64, times the ~troke. ~hen clo~d as i~ ~gure
3, the pressure to t~e s~ller ~rea 64 i~ dumped to tank
~ 7 --
allowing all the force on the larger area 62 to clamp the
die closed.
The above de~cribed sy~tem wcrks only for die closing
and therefore the ejector cyl~nder 34 is used for die opening.
~ylinder 34 is also of a double-rod type utili~ing a relatively
small net force nrea ana t~us requiring a minimal hydraulic
flow volume. Cylinder 34 pushes against fixea ou~er ~tops
35, Figure 3,to open the machine and ~ub~e~uently retract~
to withdraw a stripper pin plate (Fig. 21). We have ~ound .
1~ that substantial saving in fluid volume is realized
from this ~ystem.
HE~T TRANSFER
Die casting in a permanent mold involves the process
of transferring heat from a molten metal alloy to the wall~
of the die cavity and from the cavity to a heat exchange
medium. Accordingly, certain specific para~eters must be
maint~ined to attain the heat ~low rate desired.
In the system of the pre~ent invention, the heat
exchange medium is water and electric immersion heater~ are
used only to preheat the die to operating temperature and
thereafter the temperatures above the boilLng point o~ water
are reached by controlling the internal pre~sure of the die
cooling ca~ity J the actual heat removal be mg accomplished by
evaporation of the water as it flows through the ~yst~m in a
metered quantity.
~ he rystem is shown schematically in Figure 4 which
how immersion heater~ 66 ~ituated in the ~old ~anifold 6B
adjacent the cavity face 70 and where they preheat ~he die ~:
to operating tem~erature, ~ay 400F. The water pas~ages 72
in which the heaters are immer~ed ~re in communication with
cooliny pa~ageways 74 which interco~nect anlet and outlet
valves 76, 78 respQctively.
7 ~ ,
The surface area in the die cavity that is exposed to
the molten metal casting alloy is in proportion ~o the area of
cooling surface exposed to the water and ~he distance between
the two surfaces is sized according to the heat-trans~er rate
of the die cavity material.
~ he heat transfer from the die block to khe water is
by e~aporative cooling only. The temperature of the w~ter
within the cooling passages 72 of the die i8 maintained at an
elevated point which is conduc~ive to making good casting
finishes during the metal injection. Subsequently, when the
part is cast the exce6s heat is carried away as boiling occurs
only where an overtemperature condition exists. Therefore, no
circulation or flow of water is required within the die passages
72. As steam is generated in direct proportion to the heat
removed from the molten metal it is only necessary ~o inject
a make-up water volume slightly in excess of the ~team escaping
through the pressure relief valve 7~.
As fihown schematically in Figure 4, water from a
holding tank 80 is injected by pump means 82 into the cooling
passage 72 through the inlet valve 76 at a pressure slightly
in excesfi of the water being evaporated. As the heat trans-
ferred to the pas~ages 72 from ~he di~ 70 cause the water
in the passageway 72 to boil, the valve 78 opens under the
pressure of the steam to allow it ~o escape via a manifold
pas~ageway 84 and line 86 where the steam eon~enses and
return~ to ~he tank 80.
It will be appreciated that the heat transfer syst~m
i8 ~n integral part 4f the ~old design and fun~t~on and
pro~ides for pre~ision flow adju~tment b ~ 1~ for and adapk~ble
in design to a variety of mQld reguirements. It e~mpletely
el~minates the use of hose att~hments and ha~ the feature
of flow a~ju~tment re~entlon ~om one run ~o ~he n~x~.
_ 9 _
,__ !
Mæ~AL INJECTION UNIT
ThP metal in~ection u~i~ of the presen~ invention,
~ndicated at 40 in Figure 2 is different in principle in
numerous ways from conventional systems and which effect both
performance and safety aspects. In effect, the o~.ly similarity
to conventional systems is that it ~mploys a force to drive ~
piston which in turn crea~es an hydraulic pressure ~o fill the
mold cavity.
~he injection unit 40 is suspended in the 8Upply pot
4~, Figure 5, which comprises a double steel wall construction
having an inner wall 106 and outer wall 108 ~paced by w~bs 110.
This structure gives the strength effect of A continuous large
H-beam to resist the internal force of the molten metal ~nd
also pro~ide an air-space form of insulation. The interior of
the pot 42 is lined with a suitable insulator such as vermiculite
board 112 to which a castable refractory lining 114 is appli~d.
The temperature of the molten metal in the pot 42 is
maintained at the desired level by a pl~rality of electric:
in~nersion heaters 1ï6 (~s shown also in Figure Ba) ~paced
throughou~ the po~ 42. Each heater 116 comprises an elPment 118
encased in stainless steel tubing 120 to protect the heaters
against corrosion, ~nlarge ~he ~urface area exposed to the
casting alloy and thus reduce the watt-dens~ty.
The injection of cssting metal into the aie c~vit~ is
effected by the injection assembly indicated generally at 40
l n Fi~ure 2 ~ As ~hown in detail in Figures 8a, 8b and 10, the
a~embly 40 comprises ~1 ~teel body 122 E;uspende~ wikh~n the
confines of the furnAce pot 42 by lmeans of arms B8 which
support ~he crown 90 of the ~ss~mbly ~roffl the ~achine fr~me 12,
the crown 90 being connec~ed to the body 12Z by lo~g s~uds 92.
The body 122 incorpor~tes a laxge diam~ter eyllnder
124 ~o accommod~e the plston 128 of the ~hot ~ e ~ ~embly 46
72~
and a ~mall diameter cylindex 126 to ~ccommodate the valve 13~ g
of the selector assembly 48.
As shown conceptually ~n Figures ~ and 7, piston 128
intensifies the pressure of casting metal going to the die
and ~alve 130, depe~ding on its ~ertical positioning, selects
a ~low path from the pot supply to fill the pressure intensifier
chamber 132 at the bottom of cylinder 1~5 (Figure 6) ox selects
a flow path to the die from the pi~ton 128 (Figure 7).
Chamber 132 is connected to the selector cylinder
126 by a passageway 134 and conduit 136 in the gooseneck 44.
As shcwn in large scale in ~igure 9, selector val~e 130
has an upper head 100 and a lower head 102 interconnected by a
st~m 104 of reduced diameter. Upper head 100 mates with valve
seat 140 and lower head mates with ~eat 142, depending ~n the
operative mode. It will be noted that the spindle has upper
and lower arms 144, 146, which slidably engage the
portions of the cylinder 126, thereby leaving ample room
between the cylinder wall and the spindle body for passage o
casting m~tal thereby.
During the interval between machine cycles, ~elector
val~e 130 ~s maintained in its 6hut~off position to the nozzle
~ondu~t 136 but open to ~he pot 42. This position would be that
~t the top of its stroke ~11 with head loO engaging ~eat 140,
or the "hold and refill" position indicAted in phantom line in
Figure 9. In this ~hut-off p~sition, valYe 130 ~onst~tutes
a positive ~afeguard againsk accidental ~low to ~he machine
nozzle. At the next ~ycle - ~equen~e ~ignal, the ~alve 130 is
sh~fted to its bottom position sh~wn in Figure 9 and the
shot mode, arrow A, iæ ready.
Valve 130 is Yertically a~tuated by a ram 148 ~onne~te
to the valYe through a fr~me ~mpri~ing a pi~ton rod 150
secured to a frame made up of upper and lower horizontal cross
arms 152, 154 and vertical arms 156.
The shot cylinder 96 and in particular piston 94
th~rein is act:uated by an external supply~ infinitely variable
pneumatic pressure volumetrically sized to the under~i~e ~f
piston 94. Briefly, the shot cylinder 124 is cycled ~o as to
fill the mold cavity and ~nstantaneously withdraw the pres~ure.
Because the gate thicknes6 of a casting mold i~ thinner ~han
the casting cross-section, the gate thickness i8 the first to
solidify and does so in a fraction of a second. Therefore, an
inctantaneous reversal of the pressure does no harm to the
casting but does permit the unsolidified metal in the large
inlet runner se~tions to drain out and thereby leave only a
slush-molded tu~ular runner section attached to the part, as
will be illustrated further on. There are several advantages
to this runner-drain principle of operation. First, valuable
cycle time is not lost waiting for heavy runner sections to
601idify. Secondly, the ~ubular section of the cssting is
very strong and provides a light frame for tr~n~fer o~ ~he part
out of the mold, the runner a~d part emerge at t~e same
temperature which favors dimensional stability prior to
trimming; much le~s heat is ~mparted ~o the runner are~ of
the mold and the hollow runner6 cos~ less ~o remel~. Al~o,
the casting metal drained frcm the runn2r is ~eld a~ ~ point
just inside the nozzle tip thus minimizing ~he volume o air to
be expelled from ~he mold ca~ity.
Turning to Figure 8a7 piston 1~8 i~ ~ho~ at its
maximum ~hot position ~t the bottom o~ its stroke as~ of the
ram rod 96. When a casting i~ completely filled, plston 128
will stop, the flow of molten metal ha~ing pas~ed throush the
open port of val~e 130, arrow A, Fiyure 9, ~ fraction of ~
~econd after the lnje~tion i~ comple~ed ~d the ~ting gates
are solidified, piston 128 i5 displaced upward by pressure on
the underside of piston 94~ ~his supply is volumetrically
equal to the amount of metal contained in the runner syst~m
Df the casting die to ;l point just inside of the nozzle tip.
At this moment, piston 128 is arrested in its upward mo~ement
long enough for selector valve 130 to shift and hold the
column of metal in the nozzle and gooseneck conduit 136 in a
static position and simultaneously open the valve 130 to the
"hold and refill" position of Figure 9 so that there is
communication from the supply in the pot 42 ~nto the chamber
132. Piston 128 is th~n signaled to return to its topmost
position enab~ing the cylinder 124 to fill.
A pre~sure accumulator may be provided fGr ~he shot
cylinder 98 to include a variable pressure pneumatic pre-charge
system to provide a constant source of pressure to the cylinder
98 but being infinitely variable as required for the particular
casting being made. A casting shot is made when the opposing,
hydraulic pressure is released to drain and the piston 94 is
returned to its jtArting position of Figure 8a when the
hydraulic pressure is re-applied. However~ the first movement
of the shot-return action is accomplished by an a~xiliary
hydraulic displscement cylinder having an adjustable ~troke tc
inject a controlled amount of fluid into the shot-return
c~rcuit. This action serves tc withdraw ~he shot piston 128
and in turn provides space for the unsolidified casting metal
in the runners of th~ die to drain out leaving a shell molded
h~llow sectisn ~s mentioned pr2viously.
An ~ccumulator type receiver i~ provided to accept the
fluid di~charged from the ~ot cylinder. The fluid so
30 disChArgea i5 ~n the order o~ 500 g.p.m. and the receiver
~;ubsequently di~charges the fluid ~lowly to dr~in to tank
during the m~chine cycle perl~d.
o 13 -
1~*~7D
A safety restraint or nscotch" syst~m is 6hown
generally at 141 in Figure 8a and in detail ln Figure 12. ~h~
apparatuC prevents actuation of the shot when making machine
adjusbments and when the 'shot' mode i8 not selected.
Ram rod 96 is provided with a cammed flange 143 ~.
adapted to engage and momentarily displa~e ~ pai- of locking
collars 145, 147 when the ram 96 and piston 94 are on their
upward stroke so that flange 143 then nests ~n the 60cket 149.
Collars 145, 147 are maintained in their clo~ed position of
Figure 12 by a spring 149 and are opened against the spring
pressure by the upward movement of the flange 143. Once in the
socket 149, piston 94 and ram 96 cannot progress downward as
the closed collars engage the underside of the flange ~43~ As
~hown in Figure 12, collars 145, 147 are pivotally mounted c7~ ::
pins 151 and geared togethex by teeth 153.
Col~ar 147 has a win~ 155 held to the clcsed position
by the spring 149 on a pin 156 slidably positioned in a member
157.
An ctuator 158 has a rod 159 acti~g on the other
side of wing 155. It will be appreciated thRt ~hen ~tuator
158 displaces rod 159, collars 145 and 147 will be opened
~o allow the ram rod 96 to progrPss downwardly.
The entire injection assembly i~ ~uspended ~nd
supported by a ~ant~lever frame made up of ~he arms 88 and
cross plate 89 bolted to the frame 12 of ~he c~ting machi~e.
Alignment nd~u~tment of the a~se~bly is acoompli~ed by ecrew~
lSO for linear mov~ment along the axis or ~en~xeline of ~he
goo~eneck 44, and by screws ~62 ~or YeXti~l and lC4 for
horizontal rig~t ~nd left movement. For ~l~gnment of ~he ~ozzle
tip to the ca6ting die ln the plane of ~-x, F$gure Bb, the
ball and socket pivot 166, ~hi~h is ~l~ghtly loD~ned ~uring
- 14 -
- (
o~
the alignment proced~re, permits a 3-axis m~vement ~o be made
to locate the nozzle tip in line and ~quare with ~he casting
die.
It will be seen from Figure 10 that cantilever arms
88 have surfaces 168, 169 which when extended to lines A
and B are parallel to the centre line of the gooseneck 44.
Crown 90 has shoes 170 that ri~e on surfaces 168 ~nd 169 ~o that
adjustment of the ~crew4 160 move6 ~he assembly linearly rorrect-
~ he sequential operation of the metal in~ection
system is as follows.
A signal from the mold clamping action causes the sh~tselector valve 130 to move to its downward position o~ Figure
9 and thereby contact a positisnal sensor.
The positional sensor in turn ~ignals the restraint
system to withdr~w, effecting movement of the a~tuator 159 and
relea~ing the collars 145, 147 from the ram flange 143~
The restraint ~ensor gives signals to a~tivate the
~etal injection shot piston 94 and to initiate a timer which
~ignals the partial retract system after a fractlon of a ~econd
delay to give ~ime for ~he metal in the mold gate& ~o solidify
~nd thereafter drain out the run~er cores. At the completion
of the time delay the ~hot selector ~alve 130 returns to its
up~ard position.
The up p~sition ~f selector ~alve 13~ then signals
the shot cylinder 94 to return ~o lt~ top position znd ~g~n
the res~raint ~y~tem moves to ~ts locked po~ition.
NOZZLE
As shown in F~gure 8b ~ n~zzle extension iB provided
to bridge the dist~nce ~rom the pre~ure inten~lfier 128 to
the casting die S4 (F~gure 2~. Referrlng to Fiqure 11, the
extension ~nclude0 ~n ad~u~table ~o~t coupl~ng in~ic~ted
generally at 184 whic~ ~on~ect~ the te~m~nal e~d lB6 of the
~ 15 -
.,, .: ~
~ 7 3
gooseneck wlth the extension 188~ The end 186 of the gooseneck
riser i~ machlned to provide a peripheral flange 190 and
adjacent groove 192. ~he extens~on 188 ~erminates in a
~pherical end 194 and, when the end 194 and the end 186 are
properly aligned the conduit 136 is completed. The two ends
are held in al~gnment by mean~ of a pair of clamps 196, 198
~e~ured together by ~olts 200 as shown. The ~l~mping blocks
196, 198 are also provided w~th n plurality of ~artri~ge heaters
202 to maintnin the proper temperature level in the connec~ionO
As mentioned in the preamble of the present di~closure,
the die casting machine of the present invention utilizes a
~parting line" injection where the entry of ~he molten ~asting
metal into the die passes through the conduit 136 whi~h is
centred with the parting line of the mold and at the periphery
thereof on one side~ There must of course be a leak-proof
fluid tight æeal with the nozzle when the mold is closed and yet
there mu~t be freedom for the mold ~o open withou~ dragging or
sticking. With known nozzle tip~ o~ circular shape, the mold
has to have two half round ~h~pes to close ~bout it whereby a
condition ~xi~ts of zero clearan~e angle at ~he parting line
where the tw~ corner~ of ~he half circle are tangent to the
diameter and, si~ce a leakproo~ ~eal requires an intarference
fit, it i~ impossible to not h~ve ~ome opening fri~tion. To
sbviate this ~nd ~ther associated probl~ms, ~ squ~re, ~iamond
~hnped noz~le i~ utilized as shown ~oncep~ually ln Figures 13
~nd 14. A ~m~lar configur~tion ~ used for the c~rrier ~i~ger
58 ~Figure 22) th~ purpose of ~htch will ~e ~b~equently
diselo~ed.
A~ shGwn in Figure~ 13 and 14~ the ~ol~ h~lve~ 68 are
provided wl h ~n~rts 206 and ~h~le ~o~ u~tr~edJ the $quare
nozzle 20~ 18 ~llg~tly l~rger ~h~n ~he ~quare hole tha~
~ormed ~or 1~ ~h~n ~he mol~ ~alYe6 68 axe clo~d ~bout the
- 11;
1Yl<i~,?~
nozzle. The parting line variationfi in the nozzle to machine
~lignment might be ~n the area of plu~ ox minus 0.20-0.30 inch
and these dimensions are ~bsorbed by the elastic movement of
the injection assembly. The inserts provide oppor~unity
for precisio~ fi~ting of the parts concerned. It will be
~ppreciated ~hat all of the surfaces of the nozzle and ~he mold
will be subject to the ~ame unit force upon closing as well ~s
providing a very accurate camming means to bring the two
mold halves into proper alignment.
A preferred embodiment of the nozzle having a
multi-faceted design is shown in Figures 15 and 16 where the
nozzle 208 has sligh~ly rounded or cut off corners 210 but
does have flat sur~aces 212 for lateral alignment by in~erts
206 pro~ided on ~o~h ld halves 68. In ~ddition, ~s shown in
Fi~ure 16 the nozzle has angulated faces 214 an~ 216 in side
view which m2te with ~imilar ~aces in the mold half in~erts
206 to effect the proper linear alignment.
Figure 16 al~o illustrates a ~ross-sectional view of a
flash-gu~rd 236 which is formed by ~urface 220 o~ reduced
diameter and the adjacent curved should~r 222 in combination
with the pocket 226 and its offset ~urf~ce 228. I~ for any
reason molten metal should leak under pre~sure from the nozzle
tip, the reault~ng flash wDuld follow the arrow F, being directed
into the pocket 226 by ~he shoulder 222.
The desir~d temperature of the nozzle 208 i5 maintained
~y a nozzle cover 248 enclosing ~uitable insul~tion 250 whi~h ln
turn surrounds electric heaters 252.
MOLD
Figure 17 illu~tr~te~ the ld of the present machineO
One of the ba8~ C ~dvantages of the pre~ent m~chine over ~he
prior art i~ the ~early p~rfect thermal ~alance between the ~old
halve6 68 coupled wlth ~ie ~eparatio~ ul~an~ously ~w~y fr3
- 17 -
- (~ l
the casing. In situations having no core pin3 and ~dequate
draft angles, parts can be produced wi~hout any stripper p~ns.
~owever, e~her wlth or withou~ ~tripper8 the p~rt i~ supported
At three poin~s around the periphery of the ~rame in which it
is cast. These three poin~s ~orm a plane of reference from
which the par~ i8 subsequently transferred out of the michine.
As ~hown in Figure 17, the nozzle has made a ~a~ting in the
mold and the inlet runner 254 extenas be~ween the g~te area 256
and that portion of the mold 258 which will provide a casting
}O around the transfer finger 58 shown in Figure 22. Further
gates 260 extend from the inlet runner into the ~asting proper
262 (in this case a logo DBM and frame therearound) and ~n outlet
runner extends upwardly to surround a top core sl~de 264.
Therefore when the die halves 68 are ~imultaneously separ~ted
the casting is held by a) the top core slide 264, b) ~he n~zzle
entry 256, and c) the transfer ~inger 258, the part 262
subsequently being transferred out o~ the machine by finger 58
as will be subse~uently dèscribed in re}ation to Figure 22.
In ~ddition, when the top suppor~ing core 264 becomes a ~ore
for forming a section of the casting, italso ser~es as the
third point of support d~ring opening of the dies and virtually
eliminates the need for ~ny strlpper pins.
EJECTOR PIN RELEASE AND RETRACT MEC~ANISM
In conventional ~ie ~sting m~chine~ th~ c~t p~r~
u~ually follows the ejec~or half of ~he mold a~ it pull~ ~w y
from the cover half. Then, upon near~ng the end of the opening
ætrokes, e~ector p~ns extend and push the p~rt away fro~ ~he
mold face. In order to ensure that the ~art 1~ relea~ed ~ro~
the pin face~ ~ fusther device i8 use~ t~ ~is~urb ~t~ tend~ncy
~o 6tick ~n ~he p~ns hnd thi de~ice $8 c~m~nly Galled ~
~.
"~ui~k e~ector" ~nd it ~ctually tip~ the part out o~ the
origin~l wor~ing plane.
- 18 -
,
270
A ~quick ejector" arrangement cannot be u~ed with ~he
machine of the present in~ention as the part must be reta~ned
in it~ original workinq plane. Additionally, the part must be
held in a fixed plane as both halves of the mold are opening.
Accordingly, the die c~sting machine of the present invent~on
requires a completely different type of part ejection device
to loosen the part fr~m the mold and hold ~t in thi~ desired,
fixed position. Therefore, means are provided to bo~h loo~en
and retract the pin~ to leave the part retained ~t the
centre line of the machine and attached to the carry-out finger
5B a~ one edge and the nozzle impression at the other.
Figure 18 is a cross-sectional view o~ ~he ~jector plate
and its a~sociated mechanism for rotating the ejector pin~.
Such mechanism is provided from both sides of the cavity.
The ejector pin 228 is mounted at cne end ~n ~he
ejector plate 230 and extends through to the d~e $~ce 232. To
this end, he pin 228 has an extension pie~e 234 ~ecured ~n
~oaxial alignment with pin 228 by means o~ a tube 238 h~ving a
pair of helical ch~nnels 240 ~ormed therein ~ shown in Figure
19. Pin 228 and extenfiion 234 are welded to the tube 238 and
it~ free end i6 threadably engaged ~n a bushing 242 yield~bly
mounted again~t rotation in a pocket 246 un~r pre~ure of
bellville washex~ 266.
The mold plate 268 ~ provided with ~ shouldered
~leeve 270 hsving ~ pa~r of diametrically oppo~ed pin
foilowers 272 th~reon and which ride in the helical ~hannel6
240 a6 shown in Figure 18. ~leeve 270 is provided with a
6pline 274 (see in~et) which engsge~ ~ ~pl~ne 276 on ~ tubular
spring lock 278 when ~ rel~e pin 280 i~ retra~ed.
A~ the ~a~hlne ~lo~e~ the mold ~al~6 ~oge~her, pin 228
~n the po&it~o~ of ~igure 20a, it~ ter~ l end ~xtendlng
just beyond the die partlng li~e. A~ ~he ~lds ~lose, F~gure
-- 19 --
~ ~t-~7 ~
20b, pin 228 is linearly retracted ~gainst washers 266, under
pressu~e of about 300 lbs. Release pin i8 retracted allowing
6pring 282 to ~lide lock 278 forwardly,~engaging the 6plines
274, 276, preventing rotation of ~leeve 270. As the mold
plate 268 is pulled back towards the position of Figure 20c,
~he follower pins 272, aGting in the channels 240, rotate the
tube 238 and pin 228, the extension 234 threading it~el~ lnto
bu~hing 242. When the plate 268 reaches the position of
Figure 20c, the pin is then linearly retracted against the
washers 266 to about a 400 lb. load, pulling the pi~ 228 b~ck
from the casting by a distance "Bn, about .008 inch.
Returning the plate 268 to its clo~ing pos~tion of
Figure 20a the tube 238 is rotated back to its Fi~uIe 18
position, release 280 di6engaging the spllnes 274, 276
Rotation of the pin face in relation to the CASting
disturbs it~ attachment thereto caused by ~he pre~sure of the
casting proce~s. Secondly, BS shown in Figure 20, it withdraws
the pin a precise distance depending upon the chosen design
of the helix 240 on the tube ~38. Thus, pin 228 is bo~h
loosened and withdrawn leaving the cast p~rt completely ~ree
but 6till contained with-~n the small clearan~e between plns
extending from ~oth halves of the mold~
CORE PIN WITHDRAWA~ ..
. . .
~ eAnS ~re provided for primary core pin withdraw~l
prior to openi~g o~ the die and immediately following the
~olidu~ condition of the cast metal. ~hi~ penm~ts a true
stripping actlo~ without di~ortion of the c~ting ~8 ~ell
for le~s ~trai~ on the core pin ~tself because ~he casting
has not had ~me t~ cool ~nd shrink tight ar~und the core.
As cores are to have at lea~t .0005 lnch per in~h t~p~r per
side lt is only n~e~ary to wi~hdraw ~he ~ore ~nough to ~xeee~
the ~mount o~ cRstlng ~hriDk~e during the brie~ interv~l
- 20 -
- ` :
~ '7~
between the ~olidus time and withdrawal timeO The adYantage i5
æignificant in xespect to scrap reduction, pin breakage and
lack of distortion in the casting because ~he cores are entirely
free of ~he casting when the d~e is open.
Referring to Figure 21, the machine ejector pla~e 284
supports an air cylinder 286 which linearly actuates a rod
288 that i~ coupled at its terminal end ~o further plates 290
that retain a plurality of core pins (only 1 of which is shown),
each core pin being posit~oned within a tubular stripper pin 294.
Actuation of air cylinder 286 serves ~o advance or retract
pi~ton rod 288, plates ~90 and pin 292 within the stripper 294.
TRANSFER MECHANISM
As indicated generally in Figure 2~ the finger 58 of
the part transfer mechanism 60 carries the cast part from the
die cavity to secondary operations ~uch as tr~~ ing. When a
part is c~st from molten metal in a penmanent mold it must
remain in the mold ~ft OE solidific~tion for a long enough period
to attain suff~cient strength to be 8elf 0upporting from ~ts
~w~ weight. However it i8 of CoUr8e ~18~ desirable to open
the m~ld as ~oon as posslble ~n the ~nterest of a short cycle
time and t3 minimize shrinkage onto the male core~. In pra~tice,
~he casting #merges ce~eral hundre~ ~egreas abo~e ambient
tempera~ure Rnd if cooled ~y the conventional practice of water
quenching, severe s~rains nre built up in the par~ which can
make it di~ensionally unstable, particularly in region~ where
heavy ~ections nre ~djacent to thin fiections.
In the sy~tem acc~rding to ~he pre~ent l~vention~ .
conveyor is provided which tr~fers the p~r which has ~een
ca~t onto ~ fi~ger 58 out of ~ha mold 60 ana ~hrough ~ ~equen~e
of indexe~ untll it h~ been ~ir ~o~led 510wly ~0 ne~r ~mbient
~emperature~ The 810w cool~ng g~e~tly xedu~es ~r~n i~ the
part and pre~ents i~ to s~c~ndary m~hi~ing oper~on~ ~ith
- 21 -
greater accuracy.
In the illustrated embodiment of the present invention
the c~t part is tr nsferred from the mold~ SO to.a tri~ming
operation, Figure 22 illustr~ing the "casting~ end of the
tran~fer mechanism and Figure 23 lllustrating the "trimming~
end of the transfer mechanism.
Referring to Figures 22 and 23, the trans~er mechan~sm
generally ind~cated at 60 comprises a frame 296 whi~h carries
6prockets 2~8 and 300 on the ca~ting end of the mechani~m and
sprockets 302 and 304 on the trimming end. ~he sprocket~ are
~nterconnected with upper run side pla~es 3Q6, 308, ~prockets
302 and 304 having their own side plates 310 for a p~rpose
which will be described. Other ~ide plate~ 312 are provided ¦
between but are not connected wi~h ~prockets 304 n~ 298 for
the return lower run of the transfer mechani~m.
~s 6hown clearly i~ Figures 25 and 26, a multi-str~nd
wire cable 314 i~ provided around the ~prockets snd csble 314
h 8 much greater ten~ile strength than is required for the
working load. Cable 314 forms ~he basis of the tran~fer sy~t~m
60 ~nd to that end is provided with a plurality of ~e~al finger~
S8 which ~re loosely attached to the cable 314 to carry the
casting 56 from the mold 68. As described in rela~on to :;
Fiyure 17, the casting or ~p~rt shot" ~onsists of the ~asting
supported wi~hin the ~rame which ~ncludes the me~al inlet
runner~ 254 ~nd 260, the part 262 ~nd the g~tesf overflows
~tripper p~ds etc. and the socket end 258 which i~ ~a~ o~to
the conveyor tr~nsfer ~inger 58 a~ well P8 ~he scke~ 264 whi~h
~ay be c~st onto the ~en~re mold. As ~h~wn ~ F~gure~ 25 ~nd
26, finger 58 ~onsists D~ ~n upper bo~y ~ber 316 termina~ing
i~ ~ quare, ~iamond sh~pe tapere~ end 318. Body 318 ha8
8 lower so~ket 320 for the r~cept~on ~f plug 3 2 whi~h is
detach~bly ~ecurea to ~he ~ble 314 by a ~et ~rew 324. Plug
- ~2 -
~,t"~
322 locate~ the body of the ~nger on the cable which is
~ttached thereto by end retainerR 326. It will be s~en from
Figure 25 that there i8 3ufflcient clearance provide~ between
the interior ~ocket of the finger and the plug 322 to provide
for finger movement. The cable 314 i~ also provided wi~h
plurality of links 328 which are movably ~ec~red to the cable
by set screws 330~ each end ~f the link 328 having a tapered
bore 332 to allow for flexibil~ty in cable ~ovement when
training the li~ks around the 6prockets of the ~echanism.
It will nl80 be noted from the full view o~ ~he finger
58 in the right-hand por~ion of Figure 25 that the body member
316 has flat porti~ns providing lower and upper track engaglng
6houlders 334 and 336 respectlvely, the function of which will
subsequently be described.
The 6prockets 298 and 300 are rotatably mounted wi~hin
side plates 338 whiGh in turn are in~erconnected ~o the ~ide
rails 306 by connecting plates 340 80 that the plates 338 and
6ide rails 306 are co-planar nnd co-extensive with respect to
one ~nother. Additionally, the ~ide rails 306 æuppDrt spaced
tra~k ~mbers 342 as shown in Figure 26 and which support the
flnger 58 and ~pe~if~cally the shouldP~rs 334 thereof. It will
be noted that the track member~ 342 are ~p~ced ~o recei~e ~he
side surf~ce6 335 of fingers 58 ~s shown in the right han~ ~ide
of F~gure 25 and F~gure 26. Mcreover, the ~pro~kets al~o
include ~n arcuate ~em~er 3~4 which ~ co-extensive wîth the
tr~ck member 342 on ~he r~ 306 fiO that ~he finger 58 and
~p~cer~ 32B i6 cont~nuous both in ~he ~tr~ight 6~ctions an~
~rou~d curves so a~ not ~o pxesent Rny she~r poin~6 or wedg~
entries where debr~s ~oula be trapped ~nd ~p th~ in~exing
~ovement.
It will also be ~en from the ~o~tom p~rtion of Figure
22 th~t on it~ re~uxn run, the cable 314 c~rrie~ ~he figure 58
- 23 -
along the lower run 312 where the upper shoulders ~36 of the
flnger engage track members 342.
It will ~160 be noted fr~m the upper left hand p~rtion
of Fi.gure 22 that sprocket 300 ha~ ~paced indentation~ 346
to recelve and dri~e the ~pacers 328 and further indent~tions
348 wh~ch are provided with contours to reoeive and drive the
lower shapes of the finger~ 580
As seen in Figure 26, rail 306 iB ~ecured to the frame
12 of the die casting machine by means of a pla~e 3~0 and cap
screws 352.
~ ooking now at Figuse 23, the finger 58a wh~ch would
carry a cast part is indexed along the upper run 308 of the
track to its position at a trimming mechanism as ~hcwn generally
at 354 nnd after the ~rimming operation, the cable 314 ~raws
the finger over sprocket 302 onto track 310. Track 310 together
with the sprocket 302 which it carries is pivcted about the
centre of lower sprocket 304 and track 310 (whi~h is in effect
long ~rm) is used as a ~ulcrum about the centre of sprocket
304 to maintain the cable 314 in proper ~ension through the
~ction of a ~pring tensionin~ member 356 which is ~onnected ~t
one end 358 to the arm 310 and at its other ~nd 3S0 to ~he
~rame 296 of the tr~nsfer mechanism. A t2ke-up 6pring 362
applie~ outward pressure on the arm 310 which $s ~llowed to ::
piv~t about the centre of a Eproc~et 304 through the ~lidable
conne~tion between the ~pper portion 364 of the ar~ between
s~de plates 366 ~ecured to the upper track 308. Th~ constant
load on the e~ble 314 al~o ~erves to ma~ntai~ a con~t~nt
overall leng~h to the c~ble in re~pect to it~ ~la~tic s~s~tch
properties and ~ny mlnor di~ferences ~n po~ition o the inger~
58 ~rom one to another are ab~orbed by the purposeful loo~ene~s
of tho~e ~iagers plu~ or m~n~ 4f ~he po~tion of l~s fixed
~ttachment to ~he oable ~ 6hown ~n ~he rel~tionsh~p ~o lt6
24
Z~7~3 '
mQ~nting in Figure 25.
As the finger 5Ba i8 drawn alony arm 310 ~lth the
frame of the casting remaining ~fter~the trlnuning operat~on,
it reaches a kicker ~tation 368 where the part-shot fr~me is
kicked off the c~rrier finger 58 onto 2 belt conveyor (not
~hown) fox re~urn to the casting me~ 1 melting po~O
~ he k~cking ~tat~on ~hown ~n cro~s-section in Fi~ure
27 includes a pair of slippers 370 mounted on either side of
the track or arm 310 and which ~re connected by ~olt~ 372
acting in ~lideways 374 with a plate 376 connected to ~ linear
actuator 380~ As geen ~n Flgure 24, finger 58 with the
rem2inder of the casting frame is drawn downwardly between ~he
confines of the arcuate ends 382 of the ~lippers 380 which
effectively lie under ears 384 on the casting a~ BhOWn ~n Figure
30. When finger 58 and ~he casting frame reaches the po8i~0n
of Figure 27 by ln~ex~ng, ~he linear ~ctuator 380 i8. a~tivated
which mova3 the plate 376, bolts 372 ~nd slipper~ 370 outwardly
(to the left in Figure 23 or Figure 27) thereby kicklng off the
rem~inder of the ~ast on part which will drop d~wn onto the
conveyor and be returned to tha melt~ng pot. ~he ~i~ger 58 ~hen
returns to the casting end of the transfer mechanism ~long the
lower run of tr wk 312 ~ shown in Figure 23.
TRIMMING ~C~INE
Referring to Figures 28 ~nd 29, ~he trimming machine
354 prov~des ~ location midway between th~ two platen~ for
6upport of ~he ~r~6fer conveyor ~r~ck 30B which ~arrie~ the
pRr~s to the trim die and on through ~s re~uired~ In e~fec~,
a~ ~how~ in Flyure ~B th~ tr~mmi~g m~chine ~raddle~ the
conveyor 30B a~d finger 58 and the pPrt ~ha~ it c~rrles.
~e co~ept of ~he tri~miny machine feature~ two moving
platen~ 3B6 ~n~ 38B which ~rry the t~ffl die 390 that is
c~rried on plat~n 386 ~nd ~ tr~m punch 392 ~hat ~5 o~rried by
.
- 25 ;
platen 388. ~he tw~ platen~ advance towards one ano~her to
close about the stationary, pre-positioned ca~ing 394 within
the carrier frame. The timing of the ~wo movements i~ 6uch
that the die 390 reaches it~ fin.al positlon while the punch
392 is ~till advancing and ~ccordingly i~ ~cts ~s ~ b~ck~up
to the preliminary adv~nce of final-position locators
39~ just before the punch encounters the part to shear
it from the carr~er frame.
The trim machine 354 iB a ~w~ tie bar type with
upper and lower prestressed bars 398 and 400 mounted within
tubular compresslon m~mbers 402, 404 to provide ~ub~ta~tial
rigidity. As seen in Figure 29, bars 398 ~nd 400 ~re tilted
off a vertical line to facilitate loading of the d~e while
suspended fro~ ~n over~ead lift. A p~ir of hort 6troke
hydraulic shock absorber~ 406, 408 are positioned in 180
opposite to one ano~her ~nd on a plane o~ the m chi~e centre
line and serve to absorb the unloading shock when the punch
392 breaks through the sheared section o~ the p~rt.
One f~rm of the trimming mschine utili~e~ a ~ingle
hydraulic cylinder 410 and 412 driving each o~ the pla~ens 388
and 38b respectively alon~ the cen~re l~ne of the maehine ~x~
~nother f~rm of the ~chine fea~ure~ hydr~ ylinders 414
and ~16 ~hich ~per~te as ~n integral par~ o~ ~he platen be~ring
supports w~ich permit6 having an op~n aperture throu~h the die
platen for automatic receipt of the part a~ it ~ pu~hed
through the die ~n ~ ~ub~equent ~r~nsfer.
The punch 392 ~nd die 330 are self-al~gning.
Re~erring to ~lgure 30, a c~st p~r~ 394 ~a~ a p~r of
aper~ures 4~0 therein an~ per~pheral fl~sh 422. The par~
is carried by ~lng~r S8 lnt~ tr~fflm~ng ~pp~r~tus ~ ~how~
in Figure 28. ~he die 390, a~ ~n in ~gure 32, ha8 B
- 26 -
~ '7~'7~
peripheral ~sll~r 424 which surrounds the part and supports it
behind ~he flnsh.
Die 390 i8 secured to the pl~ten 386 by ~ pair o~
cap screws 426 and spring washers 428. While only one ~ap
screw is ~hown in Figure 32, a pair of these screws ~re provided '
and ar~ located diagonally from one another. The ~e 390
h~s a bore 430 for each cap screw 426, the diameter o the bore
being slightly larger than the body of the cap screw to thereby
allow limited movement of the die 390 on its ~oun~ing baneath
the spring washers 428.
As shown in Figures 31 and 32, punch 392 i~ sim~llarly
mounted to a riser 432 by cap screws 434 ~nd ~pring washers
436, the bore 436 ~eing slightly larger than the diameter of the
cap BcreWS 434 to allow movement of the punch 3g2 on its
moun~ing. The punch 392 and die 390 can therefore "1Oat" on
their mountings and with respect to one ~nother. :
Punch 392 is provided with a pair of di~gonally
positioned locator pins 396 for engagemen~ in aper~ure~ 438
of the die 390 and platen 386. Punch 3~2 ~lso in~ludes a
~econd pair of locating pins 440 whi~h correspsnd to the
aperturss 420 in the part 394O
In operAtion, the conveyor 308 ~nd finger 58 c~rry
part 394 to ~ts ~igure 28 position. The die 39~ i8 advanced to
its ~igure 32 po81tion to ~upport the part, ~he flo~t~g ~ie
~djusting to its position on ~he part i~ respon~e ~o ~he
contours thereofO The punch 392 ~ then ad~n~d to~rd ~he
die 390 ~nd p~rt 394, the ~pertures 420 in the p~rt re~e~ving
~he pins 440 of the punch and effectin~ aligning ~o~amen~ of
the punch on lts cap 8crew~ 434 ~o ~hat, ~ the pun~h and a~e
close, loca~ors 396 wlll be re~eived ln apertur~ ~38.
- 27 -
While the invention has been described in connection
with a specific embodiment thereof and in a specific use,
various modi~cations thereof w~ll occur to those ~killed
in the ar~ without departing from ~he spirit and scope of the
invention as set forth in the appended claims.
~ he terms and expression~ employed in ~his
disclosure are used as terms of description 3nd not of
limitation and thare ~s no intention in the~r use ~o exclude
any equivalents of the features ~hown and described or
portions thereof, but it is recognized that vaxious modif~cat$ons
~re possible within the scope of the invention claimed.
; ~8 -
