US3046621A

US3046621A - Die casting machine plunger tip

Info

Publication number: US3046621A
Application number: US774804A
Authority: US
Inventors: Glen R Morton
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-11-17
Filing date: 1958-11-17
Publication date: 1962-07-31
Anticipated expiration: 1979-07-31

Description

y 1962 G R. MORTON DIEv CASTING MACHINE. PLUNGER TIP Filed NOV. 17, 1958- GLEN RLMORTON IN VENTORI psi 3,046,621 DIE CASTING MACHINE PLUNGER TH Glen R. Morton, 7025-5. Sarpy, Omaha, Nebr. Filed Nov. 17, 1958, Ser. No. 774,804 3 Claims. (Cl. 22-68) This invention relates to cold chamber die casting machines and more particularly it is an object of this invention to provide an improved plunger tip for providing a better seal against the walls of the slot chamber so as to prevent flashing.

Heretofore plunger tips have worn away so swiftly that the replacement of the plunger tip is necessary each twenty-four hours of constant running. The replacement of the plunger tips causes expensive loss of production from down time on the machine as well as the expense of plunger replacement.

An additional disadvantage of present plunger tips has been in that their wearing away permits leakage of molten metal past the plunger, as is commonly called flashing, causing slower filling of the die cavity andmore porous castings. Also the build up of casting metal solidifying around the conventional plunger as the metal cools causes a scoring of the shot chamber cylinder and expensive loss of production during downtime for reworking of the cylinder walls.

Objects of my invention are to provide means to make a good plunger tip seal without such clearance as would cause flashing and yet Without undue friction against the cylinder walls through my concept of a plunger tip which maintains a constant maximum diameter.

This application is a continuation-in-part of my copending application Serial No. 700,850, filed December 5, 1957, and now abandoned, for Die Casting Machine Plunger Tip.

Other and further objects and advantages of the present invention will be apparent from the following detailed description, drawings and claims, the scope of the invention not being limited to the drawings themselves as the drawings are only for the purpose of illustrating a way in which the principles of this invention can be applied.

Other embodiments of the invention utilizing the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawings:

FIG. 1 is a forward end view of the plunger tip and cylinder wall of this invention;

FIGURE 2 is a view-in-section taken along the line 22 of FIG. 1; and

FIGURE 3 is an exploded view of a forward portion of the plunger tip.

The plunger tip of this invention is adapted for use in a die casting machine, not shown, having a shot chamber provided with a cylindrical inner wall 12. A plunger 14 is adapted to receive on its threaded end 16 a plunger tip 20 of this invention, the plunger tip 20 having a main body portion 22 provided with a hollow center 24 for receiving cooling water entering thereinto through the hollo w interior 26 of the plunger 14, in a conventional manner.

The forward end of the plunger rod 14 is threaded at 28 and is received in a threaded opening 29 which connects the hollow center portion 24 of the main body portion 22 with a recess 32 which opens upon the rearward side 34 of the main body portion 22.

It will be seen that the recess 32 and the opening 29, together, in effect, form an opening extending through the rearward side of the main body portion 22 providing communication with the hollow interior 24.

In accordance with this invention a soft material re- 3,946,621 Patented July 31, 1962 IQQ 2 taining portion 30 is disposed spaced apart from the forward end 34 of the main body portion 22.

The soft material retaining portion 30 extends almost completely from one side to the other transversely across the forward side 34 of the main body portion 22 although the outermost edge or circumference of the soft material retaining portion 30 is disposed inwardly of and is of a lesser diameter than the outer diameter of the main body portion 22, as best seen at 36.

Web portions 51) interconnect the soft material retaining portion 3% and the main body portion 22. The outer surfaces of the web portions 50 define segments of a cylindrical surface.

The exterior surfaces of the web portions 50 are spaced inwardly toward the axis of the plunger tip 20 from the outer surface 36 of the rearward end of the soft material retaining portion 3!), whereby the exterior of the web portions 5% define a cylindrical surface of lesser diameter than the surface defined by the exterior 36 of the soft material retaining portion '30.

The plunger tip further has a forward end portion 54 attached to and extending outwardly and forwardly from the forward end 60 of the soft material retaining portion 3%, the forward end portion 54 having a threaded cylindrical outer surface 62 on the same axis as the main body portion 22.

The forward end portion 54 has a forward plug aperture 66 extending therethrough from its forward side inwardly, the aperture 66 also extending through the retaining 'portion 3% and entering upon a space 70 disposed between the retaining portion 30 and the forward side 34 of the main body portion 22. The forward plug aperature 66 is for receiving a forward plug later described.

The main body portion 22 has a removal plug aperture 30 disposed extending through the forward side thereof and extending inwardly to the hollow center 24, the removal plug aperture being disposed opposite the forward plug aperture 66.

It is important that the forward plug aperture 66, the removal plug aperture 80, and the opening in the rearward side of the main body portion 22, which is formed by the opening 29 and the recess 32, are all disposed in alignment whereby a tool can be inserted through the recess 32 and the opening 29 and driven against the rearward side of a removal plug disposed in a removal plug aperture 80 driving the removal plug 90 against a forward plug 92 which fills the forward plug aperture 66 for driving the forward plug 92 out of the plunger tip to make pos sible the removal, replacement and also filling of the space 7d with the mass of material which is later described.

A plurality of rings are disposed forwardly of the forward side 34 of the main body portion 22 and are arranged with their exterior'surfaces in a cylindrical configuration substantially of the same diameter of the main body portion 22, the rings 110* each actually being a ring segment or a substantially complete circular ring with the exception of a cut-through portion 112 at at least one place in each ring to permit expansion of the outer diameter of the ring for completing filling and sealing the inner wall 12 of the shot chamber and as the exterior surfaces of the ring 110 wear away and as later described.

The inner diameter of the rings 110 are such that they are adapted to be received between the exterior surface 36 of the soft material retaining portion 30 and the exterior cylindrical surface of the plunger tip.

The mass of soft material 100 must be of a material adapted to change shape under normal pressures and temperatures of the shot chamber of a cold chamber die casting machine whereby the outer surfaces of the ring 11% gradually wear away, the pressure in the shot chamber will cause the forward plug 92 to be driven inwardly and reaiwardly of the tip, forcing the mass of material 100 to change its shape and to move outwardly for having a larger outer diameter, thereby exerting pressure against the rings 110 causing them to be forced outwardly against the shot chamber walls 12 for providing a snug fit to eliminate flashing.

I have found a soft aluminum alloy which is of substantially pure aluminum to be an excellentmaterial for the mass 100 and also zinc will work, although less effectively.

I have found that the rings 110 work best if formed of beryllium copper as this material tends topolish the cylinderwall 12. However other materials will also work.

As thus described, it will be seen that this invention provides a plunger tip which maintains, through the movement of the rings 110 outwardly, a substantially constant diameter regardlesstof wear on the outer surfaces of the rings 110.

Asaresult the problems of flashing are eliminated along with the great labor costs of plunger tip replacement, cylinder wallresurfacing; and also the loss of production through down-time is greatly reduced. The porosity of the castings also increases because of the possibility of maintaining a constant pressure on the molten metal in the die cavity through elimination of flashing.

Arring retaining nut 114 threadedly received on the for- Ward end portion 54 of the plunger tip 20 in final assembly, as shown in FIGURE 2, secures the rings 110 in position.

From the foregoing description, it is thought to be obvious that die casting machine plunger tip constructed in, accordance with my invention is particularly well adapted for use, by reason of the convenience and facility with which it may be assembled and operated, and it will also be obvious that my invention is susceptible of some change and modification without departing from the principlesand spirit thereof, and for this reason Ido not wish to be understood as limiting myself to the precise arrangement and formation of the several parts herein shown in carrying out my invention in practice, except as claimed.

I claim:

1. A plunger tip for a die casting machine comprising: a main body portion of cylindrical shape having a hollow center having an opening extending through its rearward side,sa soft material retaining portion spaced apart from the forward end of said main body portion providing an annular space between the material retaining portion and said main body portion, web portions interconnecting said soft material retaining portion and said main body portion, the exterior of said web portions being spaced in- 'wardly toward the axis of the plunger tip from the exterior of: the rearward end of said soft material retaining portion, a forward end portion attached to and extending outwardlyv from the forward end of said soft material retaining portion and having a threaded cylindrical outer surface having the same axis as said main body portion,

said forward end portion having a forward plug aperture extending through said forward end portion from the forward side inwardly and also through said retaining portion, a forward plug in said forward plug aperture, said main body portion having a removal plug aperture disposed extending through the forward side of said main body portion inwardly to its hollow center opposite said forward plug aperture, said forward plug aperture and said removal plug aperture and said rearward side opening of said main body portion all being disposed in alignment, a plurality of ring segments disposed forwardly of said main body portion and arranged with their exterior surfaces in a cylindrical configuration approximately of the same diameter as said main body portion, and amass of soft solid material adapted to change shape under the pressures and temperatures of die casting machine shot chambers, said mass being disposed in and filling the space between said material retaining portion and saidmain body portion whereby as the exterior of said rings wears away said forward plug moves rearwardly under the pressure in said shot chamber causing said mass of material to change shape and exert pressure against said rings to hold them outward to provide them with a substantially constant outer diameter.

2. A plunger tip for a die casting machine comprising: a main body portion of cylindrical shape having a hollow center having an opening extending through its rearward side, a soft material retaining portion spaced apart from the forward end of said main body portion, said body por tion and spaced material retaining portion defining a space therebetween web portions interconnecting said soft ma terial retaining portion and said main body portion, the exterior of said web portions being spaced inwardly toward the axis of the plunger tip from the exterior of the rearward end of said soft material retaining portion, a forward end portion attached to and extending outwardly from the forward end of said soft material retaining portion, said forward end portion having a plug aperture therethrough opening at the forward end thereof and extending inwardly to and through the space between said retaining portion and said main body portion, a plug slidably received in and sealing said plug aperture, a plurality of ring segments disposed forwardly of said main body portion and arranged with their exterior surfaces in a cylindrical configuration approximately of the same diameter as said main body portion, means attached to and disposed forwardly of said soft material retaining portion and extending outwardly alongside said rings for preventing said rings from moving forwardly off of said plunger tip, and a mass of soft solid material adapted to change shape under the pressures and temperatures of die casting machine shot chambers, said mass being disposed in and fillingthe space between said material retaining portion and said main body portion whereby as the exterior of said rings Wear away said plug moves rearwardly under the pressure in said shot chamber causing said mass of material to change shape and exert pressure against said rings to hold them outward to provide them with a substantially constant outer diameter.

3. A plunger tip for a die casting machine comprising: a main body portion of cylindrical shape having a hollow center having an opening extending through its rearward side, a soft material retaining portion spaced apart from the forward end of said main body portion and having a cylindrical outer surface of lesser diameter than said mainbody portion, said body portion and spaced material retaining portion defining a space therebetween, webportions interconnecting said soft material retaining portion and said main body portion, the exterior of said web portions being spaced inwardly toward the axis of the plunger tip from the exterior of the rearward end of said soft material retaining portion, a forward end portion attached to and extending outwardly from the forward end of said soft material retaining portion and having a threaded cylindrical outer surface having the same axis as said main body portion, said forward end portion having a forward plug aperture extending through said forward end portion from the forward side inwardly and also through said retaining portion, said main body portion having a removal plug aperture disposed extending through the forward side of said main body portion inwardly to its hollow center opposite said forward plug aperture, said forward plug aperture and said removal plug aperture and said rearward side opening of said main body portion all being disposed in alignment, a forward plug in said forward plug aperture, a removal plug in said removal plug aperture, means for preventing said removal plug from moving forwardly out of said removal plug aperture, a plurality of ring segments disposed forwardly of said main body portion and arranged with their exterior surfaces ina cylindrical configuration approximately of the same diameter as said main body portion, and a mass of soft solid material adapted to change shape under the pressures and temperatures of die casting machine shot References Cited in the file of this patent UNITED STATES PATENTS Murray Mar. 17, 1925 Lannert Mar. 8, 1938 Sauzedde Oct. 25, 1938 Bennett Oct. 18, 1949