Plastic article or earthenware shaping or treating: apparatus – Female mold and charger to supply fluent stock under... – With means to heat or cool
Utility Patent
1998-11-02
2001-01-02
Davis, Robert (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Female mold and charger to supply fluent stock under...
With means to heat or cool
C138S038000, C138S042000, C249S079000, C425S19200R
Utility Patent
active
06168415
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an improved mold insert and an improved baffle for use therewith. This invention also relates to an improved liquid barrier for use in a mold insert. Mold inserts of the type to which this invention pertains are used in machines for injection molding plastic workpieces, but this invention may be useful in other fields, such as die casting and rubber molding.
BACKGROUND OF THE INVENTION
This invention is intended for use with mold inserts of the type shown in U.S. Pat. No. 4,828,479, granted May 9, 1989 to Ronald E. Pleasant, and U.S. Pat. No. 4,959,002, granted Sep. 25, 1990 to Ronald E. Pleasant, the disclosures of which are hereby incorporated herein by reference. The '479 and the '002 patents disclose generally cylindrical mold inserts for injection molding machines which have a generally cylindrical liquid channel section with a liquid conduit groove extending circumferentially around the liquid channel section. A liquid, such as water, is circulated around the mold insert in the liquid conduit groove for cooling (or heating) portions of the mold insert. A liquid barrier is located in the groove so that the groove is double-ended, one end constituting a liquid inlet end and the other end constituting a liquid outlet end. A mold machine with which an insert is used has inlet and outlet connectors aligned with the inlet and the outlet ends of the groove so that the water or other liquid can be introduced into the liquid conduit groove.
It is known in the art to provide blind bores, by drilling for example, that extend radially inwardly from the liquid conduit groove and receive liquid to meet various cooling (or heating) needs. A simple baffle comprising a flat blade fitted to the diameter of a liquid-receiving bore may be inserted centrally therein to separate the bore into an inlet passageway and an outlet passageway. Typically, the blade is formed from brass, aluminum, or stainless steel, and a portion of the blade extends into the liquid conduit groove to divert liquid flowing in the groove into the inlet passageway formed by the blade. The blade does not extend to the bottom of the bore so that liquid diverted into the inlet passageway of the bore may flow around the bottom of the blade to the outlet passageway and back into the liquid conduit groove.
A simple, blade-only baffle, as described above, has a tendency to move or shift from its central position in the liquid-receiving bore due to pressure from the flowing liquid. This shifting of the baffle within the bore can create imbalanced flow characteristics which negatively impact the cooling (or heating) action provided by use of the baffle. To prevent shifting of the baffle within the bore, a so-called “spiral” baffle may be used in place of a blade-only baffle. A spiral baffle remains centered within its bore due to the body thereof having a generally cylindrical shape that fits snugly within the bore, thereby providing multiple circumferential engagement points with the bore. Spiral baffles also provide better cooling (or heating) action than straight baffles as a result of longer passageways for the liquid flowing through the bore created by use of a pair of drill-like, helical or spiral grooves in the baffle body. The helical or spiral grooves result in a spiral liquid inlet passageway and a spiral liquid outlet passageway in the liquid-receiving bore. The spiral baffle is similar to a straight baffle in that it does not extend to the bottom of the liquid-receiving bore. Therefore, liquid diverted into the bore may flow into the spiral inlet passageway and out of the spiral outlet passageway. A similar effect has been obtained by twisting a simple, blade-only baffle to create a longer, spiral path for the liquid.
Such prior art baffles, although commonly used, are not particularly suited for use with mold inserts of the type shown in the aforementioned '479 and '002 patents because no suitable way to positively secure the baffles into the liquid-receiving bores of mold inserts was heretofore known. The prior art baffles are typically retained in the bores merely by the frictional engagement of the baffle with the bore. In addition, although prior art baffles provide generally acceptable cooling (or heating) action, better cooling (or heating) action is desired.
The liquid barrier mentioned above is typically formed by a dam member that is either welded in place in the liquid conduit groove or is secured in the liquid conduit groove by the use of a pair of locking members that are advanced through a pair of outwardly-extending bores in the dam member and into engagement with the inwardly-facing surfaces of undercut portions of the groove sidewall, as illustrated and described in commonly owned international application, International Publication Number WO 94/09961, published May 11, 1994, and U.S. patent application Ser. No. 08/387,250, filed Feb. 13, 1995, now U.S. Pat. No. 5,647,114, which are hereby incorporated herein by reference.
In addition to or in place of the liquid-receiving bores described above, the user of a mold insert may, in order to meet various cooling (or heating) needs, drill liquid passageways extending inwardly of the circumferentially-extending liquid conduit groove and opening at mutually-spaced locations in the liquid conduit groove. To insure an adequate flow of liquid into such inwardly directed passageways, one or more additional dams or barriers are affixed inside the peripheral liquid conduit groove between the mutually-spaced openings of each liquid passageway. The provision of additional dams or barriers, by either welding or the use of locking members as described above, can be time consuming and costly. Accordingly, there exists a need to enable the user of an insert to quickly, accurately and securely assemble liquid dams or barriers into liquid conduit grooves of mold inserts.
SUMMARY OF THE INVENTION
An object of this invention is to provide an improved baffle for use in cooling (or heating) solid components, such as mold inserts for injection molding machines, by passing a liquid therethrough. A more particular object is to provide such an improved baffle wherein turbulence is created in the liquid flowing around or past the baffle to enhance the cooling (or heating) action of the liquid.
Another object of this invention is to provide an improved baffle particularly suited for use in mold inserts for injection molding machines. More particularly, an object of this invention is to provide a self-retaining baffle for use in a mold insert that is readily secured in and removed from a liquid-receiving bore provided in the mold insert.
A further object of this invention is to provide a baffle in accordance with the foregoing objects that is durable and that can be easily and inexpensively manufactured.
Another object of this invention is to provide a baffle that achieves the foregoing objects which can be used with existing mold inserts without modification thereto.
Still another object of this invention is to provide an improved mold insert and a method for assembling the same wherein baffle members provided in liquid-receiving bores are self-retaining and are easily locked into and removed from the liquid-receiving bores.
An improved baffle in accordance with this invention includes a flat blade adapted to be snugly received in a liquid receiving bore which extends transverse to a liquid conduit, for example in a mold insert. The blade separates the bore into an inlet passageway and an outlet passageway, but does not extend to the bottom of the bore. A portion of the baffle, which may be termed the head thereof, extends into the path of liquid flowing in the liquid conduit so that the liquid is diverted into and through the liquid-receiving bore. The baffle has plural fins projecting outwardly from opposite sides thereof into the inlet and outlet passageways. Liquid flowing in the passageways is partially obstructed by the fins, thereby creating turbulence in the liquid.
When used in a mold insert having an
Lafferty H. Eugene
Pleasant Ronald E.
Davis Robert
Dybvig Roger S.
Leyson Joseph
Pleasant Precision, Inc.
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