U.S. patent application number 09/804353 was filed with the patent office on 2001-07-26 for method for cleaning and lubricating an injection sleeve and plunger in a cold chamber injection unit.
Invention is credited to Coronado, Jean, Perrella, Guido.
Application Number | 20010009186 09/804353 |
Document ID | / |
Family ID | 22835119 |
Filed Date | 2001-07-26 |
United States Patent
Application |
20010009186 |
Kind Code |
A1 |
Perrella, Guido ; et
al. |
July 26, 2001 |
Method for cleaning and lubricating an injection sleeve and plunger
in a cold chamber injection unit
Abstract
A method for cleaning and lubricating an injection sleeve and
plunger tip during a fill and injection cycle in a cold chamber die
casting machine, in which the plunger tip has an annular generally
arcuate recess, lubricating nozzles, lubricating conduits and scrap
exhaust conduits. Pressurized air is released into the recess
during the injection cycle and debris is exhausted through the
scrap exhaust conduits. Upon completion of the injection cycle, the
release of pressurized air into the recess is terminated. A mixture
of pressurized air and lubricant is released through the recess
onto the injection sleeve during the withdrawal cycle. Upon
completion of the withdrawal cycle, release of the mixture of
pressurized air and lubricant into the recess is terminated.
Inventors: |
Perrella, Guido; (Westmount,
CA) ; Coronado, Jean; (St-Eustache, CA) |
Correspondence
Address: |
Anthony D. Wilson, Esq.
McCormick, Paulding & Huber LLP
CityPlace II, 185 Asylum Street
Hartford
CT
06103-3402
US
|
Family ID: |
22835119 |
Appl. No.: |
09/804353 |
Filed: |
March 12, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09804353 |
Mar 12, 2001 |
|
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09223117 |
Dec 30, 1998 |
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6237672 |
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Current U.S.
Class: |
164/472 ;
164/268 |
Current CPC
Class: |
B22D 17/2038 20130101;
B22D 17/203 20130101 |
Class at
Publication: |
164/472 ;
164/268 |
International
Class: |
B22D 011/07; B22D
011/12 |
Claims
What is claimed is:
1. A method of cleaning and lubricating an injection sleeve and
plunger tip during a fill and injection cycle of a cold chamber die
casting machine, the plunger tip having an annular generally
arcuate recess, lubricating nozzles, lubricating conduits and scrap
exhaust conduits, comprising releasing pressurized air into the
annular generally arcuate recess in the plunger tip upon completion
of the injection cycle, releasing a mixture of pressurized air and
lubricant through the annular generally arcuate recess in the
plunger tip onto the injection sleeve during the withdrawal cycle,
terminating release of the mixture of pressurized air and lubricant
into the annular generally arcuate recess in the plunger tip at the
termination of the withdrawal cycle.
2. The method of claim 1, further comprising; inclining at least
one of the lubricating nozzles to direct lubricant at the injection
sleeve.
3. The method of claim 1, further comprising; inclining some of the
lubricating nozzles to direct lubricant at the injection
sleeve.
4. The method of claim 1, further comprising; orientating at least
one of the lubricating nozzles radially outwardly to direct
lubricant at an interior of the injection sleeve.
5. The method of claim 1, further comprising; orientating some of
the lubricating nozzles radially outwardly to direct lubricant at
an interior of the injection sleeve.
6. The method of claim 1, further comprising; orientating at least
one of the scrap exhaust conduits parallel to a longitudinal
centerline of the plunger tip.
7. The method of claim 1, further comprising; orientating the scrap
exhaust conduits parallel to a longitudinal centerline of the
plunger tip.
8. The method of claim 1, further comprising; providing the annular
generally arcuate recess from behind a front of the plunger tip to
forward of a rear of the plunger tip.
9. The method of claim 1, further comprising; providing some of the
lubricating nozzles annularly about a longitudinal centerline of
the plunger tip.
10. The method of claim 1, further comprising; connecting at least
one of the lubricating nozzles to a lubrication conduits.
11. The method of claim 1, further comprising; connecting the
lubricating nozzles to lubricating conduits.
12. The method of claim 1, further comprising; orientating some of
the lubricating nozzles to direct lubricant at an inclination to
the injection sleeve, and orientating other of the lubricating
nozzles radially outwardly to direct lubricant at an interior of
the injection sleeve.
13. The method of claim 6, comprising; orientating some of the
lubricating nozzles to direct lubricant at an inclined angle to the
injection sleeve, and other of the lubricating nozzles radially
outwardly to direct lubricant at an interior of the injection
sleeve.
14. The method of claim 6, comprising; orientating some of the
lubricating nozzles to direct lubricant at an inclined angle to the
injection sleeve, and at least one other of the lubricating nozzles
radially outwardly to direct lubricant at an interior of the
injection sleeve.
15. The method of claim 6, further comprising; orientating at least
one of the lubricating nozzles to direct lubricant at an inclined
angle to the injection sleeve, and other of the lubricating nozzles
radially outwardly to direct lubricant at an interior of the
interior sleeve.
16. The method of claim 1, further comprising; connecting at least
one of the scrap exhaust conduits to a rear interior of the
generally arcuate annular recess and a rear surface of the plunger
tip.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. patent application
Ser. No. 09/223,117 filed on Dec. 30, 1998 entitled "SELF
LUBRICATING AND CLEANING INJECTION PISTON FOR COLD CHAMBER
INJECTION UNIT", and which is herein incorporated by reference.
FIELD OF THE INVENTION
[0002] This invention is in the field of cold chamber die casting
machines. More particularly, the invention relates to an injection
piston which provides improved injection, lubrication and cleaning
of the injection sleeve.
BACKGROUND OF THE INVENTION
[0003] The injection piston is comprised of a plunger tip, plunger
tip ring, a cap to retain the plunger piston ring on the plunger
tip, a lubricating chamber and a scraper and guide ring. The cap,
plunger piston ring and scraper and guide ring are fastened to the
plunger tip. An annular arcuate recess about the circumference of
the plunger tip in combination with a series of tilted and radial
lubrication nozzles form a lubrication chamber within the injection
sleeve. The extent of the lubrication chamber enables a substantial
portion of injection sleeve to be directly lubricated before
withdrawal of the plunger tip in the injection sleeve in
preparation for the filling cycle.
[0004] In cold chamber die casting, the injection piston is located
within the injection sleeve of the cold chamber die casting unit.
The injection piston is connected by a connecting rod to an
injection piston rod to an injection unit piston. The withdrawal of
the injection unit piston results in the withdrawal of the
injection piston within the injection sleeve to a fill position. In
the fill position molten metal is poured into the space in the
injection sleeve above the injection piston. Once the dies of the
cold chamber die casting machine are closed and clamped, the
injection cycle is commenced. In the injection cycle, the injection
unit piston drives the piston rod, connection rod and injection
piston upwardly within the injection sleeve transporting the molten
metal in the injection sleeve into the runners and die cavities. As
soon as the molten metal in the dies is firm, the injection unit
piston withdraws the injection piston to the fill position within
the injection sleeve in position for commencement of the subsequent
cycle.
[0005] One problem associated with cold chamber die casting
machines is that during the injection cycle small amounts of molten
metal escape between the inside of the injection sleeve and the
injection piston or through a piston ring and form scrap on the
interior of the injection sleeve. The problem results from the
inside diameter of the injection sleeve expanding and contracting
because of thermal expansion caused by receipt of molten metal
followed by relative cooling during the injection cycle when the
molten metal is removed from the injection sleeve. The injection
plunger is also subject to expansion and contraction. Piston rings
are also subject to thermal expansion and contraction which may
result in a gap through a split ring or rings for the molten metal.
It is important that scrap formed from metal be removed from the
interior of the injection sleeve to prevent scoring of the
injection sleeve which aggravates the problem. Scrap not removed
when the injection piston is withdrawn from the interior of the
injection sleeve may be removed in the injection cycle and enclosed
in a casting resulting in a possible reject.
[0006] Another problem associated with cold chamber die casting
machines is that the injection piston or the piston ring of the
injection piston must be in sliding contact with the surface of the
injection sleeve to prevent some molten metal under pressure from
escaping between the injection piston and the injection sleeve. The
injection piston contacts the injection sleeve during the
withdrawal stroke as well as the injection stroke. It is necessary
to lubricate the injection piston to prevent wear and lessen
scoring by contact movement of the injection piston on the surface
of the injection sleeve.
[0007] U.S. Pat. No. 5,076,343 discloses a die cast plunger
lubrication system. The plunger tip includes a lube groove through
which lubrication is forced out on the forward stroke. The
disclosure states that the lubricant may be output to the outer
surface of the plunger rod instead of through a lube groove. U.S.
Pat. No. 4,420,028 discloses an orifice located adjacent to the
piston head.
[0008] In both the above inventions there is a substantial area of
the plunger tip or piston head in contact with the interior of the
sleeve. In both patents the lube groove or lube orifice is very
small in comparison to the length of the plunger tip.
[0009] The plunger tip of the instant invention does not contact
the surface of the injection sleeve. The plunger piston ring which
is located in an annular recess on the front outside surface of the
plunger tip is the first part of the injection piston in permanent
contact with the interior of the injection sleeve, the second part
is a scraper and guide ring located in an annular recess on the
rear side of the plunger tip. The plunger piston ring is retained
in the annular recess on the plunger tip by a cap in the form of a
disc fastened to the face of the plunger tip. The contact surface
between the surface of injection piston and the surface of the
injection sleeve is the outer surface of the plunger piston ring.
The contact surface of the plunger piston ring is substantially
less than that of the contact surface between the plunger or
plunger tips disclosed in the above patent. The lubrication chamber
and associated annular radial and tilted pressurized air and
lubrication nozzles apply pressurized air and lubrication directly
to a substantial portion of the injection sleeve initiated upon
withdrawal of the injection piston.
[0010] Japanese Patent 8,068,257 discloses the use of a series of
split rings located side by side on a plunger tip to decrease the
surface to surface contact between the injection plunger and
injection sleeve. The plunger piston ring of the instant invention
does not provide a continuous passage through the ring as does a
split ring. The plunger piston ring of this invention is comprised
of a ring of tool steel in which a series of parallel alternately
disposed inclined slots are cut alternately in the front side and
rear side of a ring of tool steel. The inclined slots proceed two
thirds to three quarters of the distance through the plunger piston
ring. The parallel alternate inclined slots result in a plunger
piston ring which is flexible without providing any opening
extending completely through the plunger piston ring. The plunger
piston ring acts as a guide for the plunger tip which is not in
contact with the inside of the injection sleeve. The surface area
of the plunger piston ring in contact with the surface of the
injection sleeve in less than the surface contact of plunger,
plunger tips, combined plunger tips and rings or series of plunger
split rings used in combination disclosed in the prior art. The
lesser surface area contact results in less metal to metal contact
between the injection piston and the injection sleeve during each
cycle.
SUMMARY OF THE INVENTION
[0011] The injection plunger of this invention provides a plunger
tip having an annular lubricating chamber commencing behind the
plunger piston ring. Forwardly tilted nozzle holes blow pressurized
lubricant and air at the interior of the injection sleeve in the
vicinity of the plunger piston ring. Radial nozzle holes blow
pressurized lubricant and air directly at the surface of the
injection sleeve are also located within the annular lubricating
chamber. The lubrication and pressurized air blow commences while
withdrawal of the injection plunger is initiated and terminates
when the injection plunger reaches the fill position. The combined
use of tilted and radial nozzles located annularly within the
lubricating chamber provides lubrication directly at the surface of
the injection sleeve facing the annular lubricating chamber.
[0012] Immediately to the rear of the lubricating chamber is a
scraper and guide ring whose outer diameter is less than the inside
diameter of the injection sleeve. The scraper and guide ring serves
to remove metal scores located on the inner wall of the injection
sleeve. The rear of the lubricating chamber is vented to the
outside by a series of circular openings defining cylindrical
conduits through the back of the plunger tip. The series of
cylindrical conduits have longitudinal centerlines parallel to the
longitudinal centerline of the plunger tip, said apertures being
equally spaced about the longitudinal centerline of the plunger tip
commencing at the back of the lubricating chamber.
[0013] During the injection cycle as the plunger tip moves forward
the scraper and guide ring removes scores from the inside of the
injection sleeve which fall into the lubrication chamber. Upon
initiation of piston withdrawal, lubrication and pressurized air
are blown through the tilted and radial nozzles into the
lubricating chamber thus driving scrap and loose lubricant out the
scrap conduits in the rear of the lubricating chamber.
[0014] The injection piston and more particularly the plunger tip,
plunger piston ring and cap decrease the amount of molten metal
passing by or through the plunger, plunger tip or plunger piston
ring resulting in a cleaner surface on the interior of the
injection sleeve. The application of lubrication directly to a
substantial length of the injection sleeve facing the lubricating
chamber commencing proximate the plunger piston ring sleeve
decreases the wear on the plunger piston ring and the surface of
the injection sleeve. The quality of castings is improved by
decreasing solid impurities within the injection sleeve resulting
from little molten metal passing between the plunger ring and the
injection sleeve combined with improved removal of solids.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a cross-sectional view of the principle parts of
the injection system of a cold chamber die casting machine with the
injection piston in retracted position prior to receipt of the
molten metal.
[0016] FIG. 2 is a cross-sectional view of the injection system of
the cold chamber die casting machine of FIG. 1 with the injection
piston in the forward position after having forced the molten metal
into the runners and die cavities.
[0017] FIG. 3 is a partial side and cross-sectional view of the
connecting rod, plunger tip, plunger piston ring, and cap with the
retaining bolts retaining the cap on the face of the plunger tip
and front side of the plunger piston ring.
[0018] FIG. 4 is a rear view of the back of the plunger tip of FIG.
3 disclosing a series of scrap exhaust holes.
[0019] FIG. 5 is a top view of the plunger piston ring for the
plunger tip showing a series of equally special slots commencing in
the front side of the plunger piston ring.
[0020] FIG. 6 is a side view of the plunger piston ring for
application to the plunger tip showing a number of alternately
disposed parallel inclined slots in the injection piston ring
commencing alternately on the front and rear sides of the plunger
piston ring.
[0021] FIG. 7 is a top view of the retaining cap for the plunger
tip showing a series of equally spaced countersink holes.
DETAILED DESCRIPTION
[0022] Referring to FIG. 1 there is shown a portion of a cold
chamber die casting machine 1 and an injection unit 2 for the cold
chamber die casting machine. The portion of the cold chamber die
casting machine 1 shown in FIG. 1 is the stationary right hand side
platen 3. The stationary die half 4 is mounted on the stationary
right hand side platen 3. FIG. 2 shows the travelling left hand
side platen and the travelling die half 5 in closed position in
contact with stationary die half 4. The injection sleeve 6 inclines
upwardly within the stationary right hand side platen 3 and ends
inside the base of stationary die half 4. Injection sleeve clamp 7
maintains the injection sleeve 6 in position in the stationary
right hand side die half 4. In FIG. 1 the plunger tip 8 of
injection unit 2 is shown near the bottom of injection sleeve 6 in
the lower or filling position. The plunger tip 8 is connected by
connecting rod 9 to saddle 10 of injection unit 2. The saddle 10 is
in turn connected to injection piston rod 11 which in turn is
fastened to the injection unit piston for the injection unit 2,
which piston is not shown. The saddle 10 receives a flexible hose
12 for carrying plunger tip coolant through the saddle 10.
Connector nut 13 is the coolant plug.
[0023] As seen in FIG. 3 the plunger tip 8 has an annular recess 14
about the exterior of the front face 15 of the plunger tip 8. The
plunger piston ring 16 is located in the annular recess 14. The
outside diameter of the plunger piston ring 16 is greater than the
outside diameter of the plunger tip 8 and in fixed and moving
contact with the inside of the injection sleeve 6. The injection
piston ring 16 is maintained in the annular recess 14 by the cap 17
which is secured to the face 15 of the plunger tip 8 by threaded
retaining bolts 18 which are placed in openings defining apertures
19 in ca 17 and secured in openings defining threaded apertures 20
located on the face 15 of the plunger tip 8.
[0024] Referring to FIG. 3 the side of the plunger tip 8 includes
an annular recess 14 commencing behind the plunger piston ring 16
and extending for over a third of the length of the plunger tip 8.
When the plunger tip 8 is placed in the injection sleeve 6 as seen
in FIG. 3, the annular groove creates a lubrication chamber 24. A
series of radial lubrication and air nozzles 25 are located
annularly about the longitudinal centerline of the plunger tip 8. A
series of forwardly inclined lubrication and air nozzles 26 are
also located annularly facing towards the front of the plunger tip
8. The radial lubrication and air nozzles 25 and the inclined
lubrication and air nozzles 26 are connected through lubrication
and air conduits 27 and 28 to the same annular lubrication and air
supply conduit 29 located on a front surface of the connecting rod
9. The annular lubrication and air supply conduit 29 is connected
through the connecting rod lubrication and supply conduit 30 to the
pressurized lubricant and air supply in the saddle 10 which in turn
is supplied through the flexible hose for pressurized lubricant and
air supply 31.
[0025] An annular scraper and guide ring recess 32 located near the
rear or the plunger tip 8 immediately behind the lubrication and
air chamber 24 has a scraper and guide ring 33 mounted therein. The
outside diameter of the scraper and guide ring 33 is slightly less
than the inner diameter of the injection sleeve 6. The scraper and
guide ring is split in half by an inclined slot. The scraper and
guide ring is mounted on the plunger tip 8 in an annular recess on
the plunger tip. The inclined slot provides flexibility to the
scraper and guide ring. A series of cylindrical openings defining
scrape exhaust cylinders 34 extend from the back of the lubrication
chamber 24 through the rear wall 35 of the plunger tip 8. As seen
in FIGS. 3 and 4, the centerlines of the scrap exhaust cylinders 34
are parallel to the longitudinal centerline of the plunger tip 8.
FIG. 3 and 4 also disclose a central opening in the plunger tip 8
defining a cylindrical space 36 within the plunger tip 8. A
cylindrical conduit 37 extending through the connecting rod 9 is
used to circulate a coolant to control the temperature of the
plunger tip 8.
[0026] Referring to FIG. 5, there is disclosed a plunger piston
ring 16 having a series of inclined parallel slots 21 with
alternate slots 21 commencing from the front 22 and rear 23 sides
of the plunger piston ring 16. The slots 21 are inclined at
15.degree. relative to a plane on the longitudinal centerline of
the plunger piston ring 16. The slots 21 extend from the front 22
or rear 23 of the plunger piston ring 16. The slots 21 extend from
the front 22 or rear 23 of the plunger piston ring 16 two-thirds to
three-quarters of the distance towards the opposite side of the
plunger piston ring 16. The multiple slots 21, forty-eight in
number, are twenty thousands of an inch wide. The multiple parallel
inclined alternate slots provide flexibility but no passage from
the front side through to the rear side of the plunger piston ring.
The plunger piston rings 16, are machined from tool steel. After
cutting the slots 21 in the injection piston ring 16 the injection
piston ring 16 is metal hardened, finished and subsequently
nitrided.
[0027] The cap 17 shown in FIGS. 7 and 8 is also machined from tool
steel so that the cap 17 and injection piston ring 16 which are in
contact with one another have the same coefficient of thermal
conductivity. The plunger piston ring 16 is mounted sliding fit
into the injection sleeve 6.
[0028] The plunger tip 8 machined from high strength beryllium
copper mold alloy has a higher coefficient of thermal conductivity
than tool steel. The cap 17 and plunger piston ring 16 made of tool
steel have a lower coefficient of thermal conductivity than the
alloy of the plunger tip to keep the molten metal in the injection
sleeve liquid during filling and injection. The high strength
beryllium copper alloy of the plunger tip 8 has a high coefficient
of thermal conductivity which enables the tip 8 to be cooled by
water circulating through the central base of the plunger tip 8.
The high strength beryllium copper alloy of the plunger tip 8
provides peak hardness and superior wear resistance compared to
that of tool steels.
[0029] The alternate opposed inclined parallel slots 21 in the
plunger piston ring provide the plunger piston ring 16 with
flexibility so that if the injection sleeve 6 becomes uneven due to
thermal expansion the outside of the plunger piston ring 16 remains
in contact with the inside wall of the injection sleeve 6. The
flexibility of the injection piston ring 16 provides less wear on
the inside of the injection sleeve 6 than conventional thermal tips
without plunger piston rings or split rings which permit some
molten metal to bypass the split rings when they are subject to
thermal expansion and pressure. The position of the injection
piston ring 16 at the front outside corner of the plunger tip 8
provide a guiding advantage for the plunger tip 8. When the
injection piston ring 16 and the injection sleeve 6 wear, the
invention provides for easy removal of the plunger piston ring 16
and substitution of the same or a slightly larger plunger piston
ring 16. The worn plunger piston ring is removed by removal of the
threaded retaining bolts 18, removal of cap 17, removal of piston
ring 16 and substitution of a new plunger piston ring 16, which may
be the same size or slightly larger depending on sleeve wear and
condition, which is then secured to the plunger tip 8 as earlier
described.
[0030] In operation, the cycle commences with the injection unit 2
in the fill position shown in FIG. 1. As seen in FIG. 2 the
travelling left hand side platen and travelling die half 5 are open
and a sufficient distance from the stationary right hand side
platen 3 and stationary die half 4 to permit molten metal to be
poured into the injection sleeve 6. Molten metal is poured into the
open injection sleeve 6. The molten metal in the injection sleeve 6
is in contact with the sides of the injection sleeve 6, cap 17, and
the edge of the plunger piston ring 16. The cap 17 and the plunger
piston ring 16 are machined from tool steel which has a low
coefficient of thermal conductivity relative to the plunger tip 8.
The low coefficient of thermal conductivity of the cap 17 and the
plunger piston ring 16 assist in maintaining the molten metal in
contact with the cap 17 and plunger piston ring 16 in a fluid
state.
[0031] When the pouring of the molten metal into the injection
sleeve 6 is complete, the travelling left hand side platen and
travelling die half 5 close on stationary right hand side platen 3
and stationary die half 4. Following closing the die halves are
clamped shut and the injection unit 2 moves from the open position
shown in FIG. 1 to the injection position shown in FIG. 2. As the
injection unit 2 moves upwardly in injection sleeve 6 the scraper
and guide ring 33 of injection plunger 8 scrapes any metal scores
located on the inside of the injection sleeve 6 into the
lubrication chamber 24.
[0032] As the injection unit 2 moves from the fill position shown
in FIG. 1 to the injection position shown in FIG. 2 the molten
metal is forced from injection sleeve 6 into die halves 4 and 5.
When the molten metal has solidified the clamping pressure is
released and lubrication mixed with air is blown onto the surface
of the injection sleeve 6 through inclined lubrication and air
nozzle 26 and radial lubrication and air nozzles 25. The inclined
lubrication and air nozzles 26 are directed at the injection sleeve
6 immediately behind the plunger piston ring 16. As the inclined
lubrication and air nozzles 26 and radial lubrication and air
nozzles 25 are located around the circumference of the generally
arcuate annular recess in plunger tip 8, all the surface of the
injection sleeve 6 facing the lubrication chamber 24 is lubricated.
Following termination of clamping pressure and commencement of
lubrication the injection unit 2 is withdrawn from the injection
position shown in FIG. 2 to the fill position shown in FIG. 1. When
the injection unit 2 reaches the fill position, the lubrication is
turned off and the injection unit 2 is ready for commencement of
the next sequence.
[0033] Following release of clamping pressure after the molten
metal has solidified the moving platen and travelling die half 5
are withdrawn from the fixed platen 3 and fixed die half 4.
[0034] The injection piston comprised of the plunger tip 8, the
flexible plunger piston ring 16 and cover 17 are effective in
preventing molten metal from bypassing plunger piston ring 16
through which molten metal under pressure may escape.
[0035] The plunger piston ring 16 does not provide any path through
the plunger piston ring 16. The location of inclined lubrication
and air nozzles 26 and radial lubrication and air nozzles 25 about
the circumference of the generally arcuate annular recess in the
plunger tip 8 provides for lubrication of all the inner surface of
the injection sleeve 6 facing the lubrication chamber 24. The
scraping and removal of debris through exhaust conduits 34 during
the injection stroke decreases wear of the surface injection sleeve
6 and the plunger piston ring 16.
[0036] The invention in its broadest aspect relates to a plunger
tip 8 having a lubrication chamber 24 with inclined lubrication and
air nozzle 26 and radial lubrication and air nozzles 25 about the
generally arcuate annular recess in the plunger tip 8. While the
invention in its broadest aspect has been described in association
with a plunger tip 8 having a plunger piston ring 16 and a cap 17,
it will be recognized by those skilled in the art that the
lubrication chamber 24 together with inclined lubrication and air
nozzles 26 and radial lubrication and air nozzles 25 about the
generally arcuate annular recess in the plunger tip 8 may be
utilized as part of plunger tips utilizing other means to prevent
molten aluminum to pass between the plunger tip 8 and the injection
sleeve 6.
* * * * *