Metal founding – Means to shape metallic material – Pressure shaping means
Reexamination Certificate
1999-12-22
2001-11-06
Nguyen, Nam (Department: 1722)
Metal founding
Means to shape metallic material
Pressure shaping means
C164S314000, C092S187000
Reexamination Certificate
active
06311761
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a plunger tip such as is used in die casting apparatus as a piston at the end of a plunger rod operable in what is termed the shot sleeve of the apparatus for forcing a charge of molten metal out of the sleeve into the die of the apparatus, and more particularly to such a plunger tip which is self-aligning in the sleeve.
Reference may be had to the following U.S. patents for background on plunger tips generally of the class described:
U.S. Pat. No.
Title
Issue Date
4,154,288
Injection Molding Machine Having
May 15, 1979
Swivel Shot Tip Assembly
4,311,185
Injection Piston for Die Casting
January 19, 1982
4,334,575
Method for Cooling a Plunger Tip
June 15, 1982
in a Die Casting Machine of the
Cold Chamber Type and
Apparatus Therefor
4,598,762
Plunger for a Casting Machine
July 8, 1986
4,667,729
Shot Tip for Cold Chamber Die
May 26, 1987
Casting Machine
4,754,799
Process for Die-Casting Aluminum
July 5, 1988
Alloys of Low Iron and High
Aluminum
4,842,039
Self-Aligning Plunger Tip
June 27, 1989
4,886,107
Piston for Cold Chamber
December 12, 1989
4,899,804
Plunger Tip for Cold Chamber Die
February 13, 1990
Cast Machine
5,076,344
Die-Casting Process and
December 31, 1991
Equipment
5,370,171
Die-Casting Process and
December 6, 1994
Equipment
BRIEF SUMMARY OF THE INVENTION
Among the several objects of the invention may be noted the provision of a plunger tip of the type having ball and socket articulation for misalignment corrections similar to that shown in the above-listed U.S. Pat. No. 4,154,288 and 4,842,039 of improved construction for effecting good cooling of the tip; the provision of such a plunger tip which is economical to manufacture and reliable in operation; and the provision of such a tip with a replaceable head, which may be made of beryllium-copper alloy as in the above-listed U.S. Pat. No. 4,667,729.
In general a plunger tip of this invention is adapted for attachment to the forward end of a plunger rod for forcing molten metal from the shot sleeve into the die of die-casting apparatus. The plunger rod (not a part of this invention) has a threaded socket extending axially inward from its forward end and a tube for coolant extending forward out of its forward end. The tip per se comprises an annular body having a rearward end portion of such peripheral outline as to be reciprocal in the shot sleeve and an integral cylindrical hollow extension extending forward from said rearward end portion coaxial therewith and of smaller peripheral outline. Said rearward end portion has a rear face and said body has a part-spherical recess in said rear face. The hollow of said extension extends from said recess to the forward end of said extension. An elongate tubular fitting having at one end thereof constituting its forward end a spherical formation is seated in sealed relation in said part-spherical recess, said fitting having a part engageable by a tool for turning it rearward of said spherical formation and an externally screw-threaded cylindrical portion rearward of said tool-engageable part for being threaded into said socket of said plunger rod. The fitting, being tubular, has a generally axial bore extending from its rearward end to the hollow of said extension for reception of the said coolant tube of said plunger rod with a space between the external surface of the tube and the internal surface of said bore, and is retained in assembly with the body with said spherical formation in the part-spherical recess by retainer means fastened on the rear face of the body. The retainer means is formed to provide a part-spherical recess complementary to the above-mentioned part-spherical recess thereby providing a spherical recess having the spherical formation of the fitting therein in sealed relation to said body and retainer means. A cup-shaped head is provided having an annular wall attached on said extension adapted for sliding sealing engagement with the internal surface of said shot sleeve and a forward end wall spaced forward of the forward end of said extension.
Other objects and features will be in part apparent and in part pointed out hereinafter.
REFERENCES:
patent: 4154288 (1979-05-01), Borgen
patent: 4311185 (1982-01-01), Zimmerman
patent: 4334575 (1982-06-01), Miki et al.
patent: 4459900 (1984-07-01), LaBouff
patent: 4598762 (1986-07-01), Glas
patent: 4667729 (1987-05-01), Zecman
patent: 4754799 (1988-07-01), Robinson
patent: 4842039 (1989-06-01), Kelm
patent: 4886107 (1989-12-01), Zecman
patent: 4899804 (1990-02-01), Hammerer
patent: 5076344 (1991-12-01), Fields et al.
patent: 5370171 (1994-12-01), Fields et al.
patent: 2-46961 (1990-02-01), None
Justis James Eric
Steininger Ronald G.
Lin I.-H.
Nguyen Nam
Senniger Powers Leavitt & Roedel
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