Plastic article or earthenware shaping or treating: apparatus – Preform reshaping or resizing means: or vulcanizing means... – Including both heating and cooling means
Reexamination Certificate
1999-10-29
2002-05-28
Nguyen, Nam (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Preform reshaping or resizing means: or vulcanizing means...
Including both heating and cooling means
C425S388000, C425S326100
Reexamination Certificate
active
06394782
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to vacuum sizers for extruded plastic profiles, and more particularly the present invention relates to modular vacuum sizing devices which are such that differing vacuum sizer dies can be assembled and disassembled into a vacuum sizer box without the necessity to realign the dies.
BACKGROUND OF THE INVENTION
The art of extruding complicated profiles and shapes of an extrudable thermoplastic material, for subsequent use in many different manners, is well known. For example, many different forms of extruded plastic are used as parts, body trim, and so on, on automobiles. Other extruded plastics materials are used for such purposes as picture framing and the like. Still other examples for the use of extruded plastic materials include trim around bathtubs, door openings, door edges of cabinet doors used in bathrooms and kitchens, and so on.
However, there are several fields in which highly complicated extruded plastics profiles are used, where the size or calibration of each profile is critical. One field, in particular, where such criteria exist is the field of windows and doors which are made for domestic, industrial, and commercial purposes, where the frame of the window or door into which window glass or a door panel is placed, or the outer frame which is placed in a suitable wall opening, are formed in extruded plastic. Because different profiles fit to one another, or must have specific dimensions so as to accommodate the placement of glass panels, for example, or may sometimes be formed as a co-extrusion of a hard plastics material with a soft plastics material which may be intended to be used as a sealer or gasket, the ability to produce the plastic extrusions with defined dimensions having very small tolerances, is critical.
Accordingly, a body of art has been developed in respect of vacuum sizing boxes—sometimes referred to as vacuum calibrators—through which the extruded plastic profile is passed, and in which the size or dimensions of the extruded plastic profile are carefully controlled by the use of vacuum to pull the plastic material to the outer edges of a specifically shaped passageway as the extruded profile is passed therethrough. However, the construction of vacuum sizer boxes is very expensive. Each box requires a base plate, a top plate, and side plates, together with appropriate connections to cooling water and vacuum pumps so as to cool and size the extrusion as it passes through the vacuum sizer box. Heretofore, it has been necessary to build a different and complete vacuum sizer box for each different profile which is to be extruded. Changing vacuum sizer boxes to accommodate a different profile has required considerable down time of the extrusion line.
Still further, it sometimes happens that the extrusion line must be stopped for one reason or another and, if so, it may be necessary to disassemble the vacuum sizer box, take out the sizing dies and clean them, and then reassemble the vacuum sizer box. Heretofore, that has meant that the vacuum sizer dies in the vacuum sizer box must be realigned, which is a lengthy, time-consuming process, resulting in still further down time for the extrusion line.
As an example, every time an ordinary vacuum sizer box is required to be disassembled, vacuum lines and water hoses must be disconnected and, of course, the alignment of the passageways of individual dies which are bolted together inside the vacuum sizer block is lost. One approach that has been taken in the past to avoid the requirement for realignment has been to create sizing dies which have longer lengths. That, in turn, has significantly increased the cost of production of such dies.
On the other hand, the present invention significantly decreases the cost of production of vacuum sizing boxes, and it significantly decreases the down time of an extrusion line either for changing vacuum sizing boxes to accommodate a different profile, or to clean the dies. These advantages are achieved primarily by the provision of a pre-assembled base plate and side plate for a vacuum sizing box, which provide reference planes arranged perpendicularly one to the other. Then, a plurality of vacuum sizer die elements is provided, each of which is rectangular (or square) and each of which has two reference surfaces—one at the bottom and the other at one side—which fit against the reference planes provided by the bottom plate and side plate. The vacuum sizing profile is carefully and precisely machined into each vacuum sizer die element, with particular emphasis on the placement of the profile with respect to the reference surfaces which have been machined on two sides of the die to fit against the reference planes. Thus, assembly or reassembly of the vacuum sizer box is easily accommodated without the necessity for realignment of the die elements.
Moreover, the present invention provides that the vacuum lines and water lines may be permanently connected to the vacuum sizer box, by connecting vacuum lines to the base plate and providing appropriate holes and slots in the base plate and one or more of the die elements—as described hereafter.
Also, removable side plates can be fitted with water passageways, so there is no necessity for connecting, disconnecting, and/or reconnecting of water lines.
Thus, in keeping with the present invention, it is merely necessary to place a new group or groups of vacuum sizer die elements against the reference planes which are fitted permanently in place in the extrusion line, and then reassemble the other side plate or plates, and top plate of the vacuum sizer box, all of which can be done quite quickly and without the necessity to realign the die elements.
In the usual practice of the present invention, as discussed in greater detail hereafter, the individual vacuum sizer die elements are cut into two sections, an upper section and a lower section, which makes assembly and cleaning much easier and quicker. Moreover, testing and proving the vacuum sizer die elements may be made easier, especially if it may develop that there is a necessity to provide for an additional or further vacuum domain in any particular region of the profile. As will become evident hereafter, the placement and/or relocation of vacuum passages in vacuum sizer die elements in keeping with the present invention, is simplified over that which has gone before.
DESCRIPTION OF THE PRIOR ART
DeZEN Canadian Patent No. 1,154,218 teaches a vacuum sizing device which includes a plurality of pairs of upper and lower sizing elements that are clamped between upper and lower backing members. However, all of the lower elements are identical to one another, and all of the upper elements are identical to one another; and each of the upper and lower elements is such that it has uniform cross-sectional shape throughout its length. Each individual element is individually attached to both a source of vacuum and a source of cooling fluid, and contains a vacuum chamber and a cooling fluid chamber. Assembly and disassembly of the vacuum sizing device requires connection, disconnection, and/or re-connection, of a plurality of vacuum and cooling fluid conduits.
MELKONIAN U.S. Pat. No. 5,288,218 teaches an extrusion calibrating apparatus which is connectable to external sources of cooling and vacuums, and which is for use in the calibration of exterior profiles of hollow thermal plastic extrusions. The assembly of the extrusion calibrating apparatus includes upper and lower cover plates, each having a pair of vacuum manifolds, together with upper and lower vacuum plates each having vacuum slots and supply and return water channels, and a heat conducting calibrating insert which is removably positioned within an interior chamber between the vacuum plates. The removable heat conducting calibrating insert is designed to pass through an access opening formed when an upper cover plate and the upper vacuum plate are rotated into the open position. The insert has a forward face and rearward face, with the calibrating aperture corresponding to the exterior pr
(Marks & Clerk)
Alloy & Cooper International Inc.
Heckenberg Donald
Nguyen Nam
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