Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – To produce composite – plural part or multilayered article
Reissue Patent
1999-10-22
2001-08-28
Silbaugh, Jan H. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
To produce composite, plural part or multilayered article
C156S108000, C156S500000, C264S177160, C425S113000, C425S466000, C425S19200R
Reissue Patent
active
RE037341
ABSTRACT:
TECHNICAL FIELD
This invention concerns a device for extruding a profiled cord of polymer onto the periphery of an essentially state-shaped object, in particular onto the periphery of a pane. The device comprises an extrusion head in relative displacement along the edge of the plate, where it deposits a profiled cord composed of a polymer at the outlet from a calibrated nozzle. The invention concerns, more specifically, the case in which the plate is moved while the extrusion head has only reduced mobility and is generally retained in a fixed position.
BACKGROUND OF THE INVENTION
It is known in the art to utilize various devices for depositing a profiled frame onto the periphery of a pane, such as an automobile glazing. These devices comprise supporting and displacing elements for the pane onto which the profiled frame is to be deposited with the relative movement between pane and extrusion head along the edge of the pane being produced to place the frame on the peripheral edge of the pane. The relative movement along the edge is produced by displacement of one of the extrusion head or the pane, for example, by a robot. In either case, the head is supplied with fluid polymer from a reservoir. When the head moves relative to the pane, the supply of polymer accompanies its movement or is connected to the head by a flexible pipe connected to a fixed distributor. Movement of the edge of the pane relative to a fixed extrusion head is described in European Patent Applications EP-0 585 129 and EP-0 493 068. Many documents describe the technique of extrusion of a polymer frame onto the periphery of a plate, such as European Patent Applications EP-A-121 481 and EP-A-524 092.
The thickness tolerances of the panes are not negligible and it is therefore necessary for the extrusion heads of the above type to accept the thickest panes of a given type (i.e., an upper limit of the tolerance on the thickness). However, for all the panes of a smaller thickness, the fluid polymer can escape during extrusion through the slot or slots left free between the wall faces of the extrusion head and the surfaces of the pane. A deposit is thus left on the pane after extrusion, which must be removed in a supplementary phase of the production process.
Since the tolerance of automobile panes is not precisely controlled by the pane manufacturer, it is difficult to precisely place a polymer frame on the edge of the pane. To avoid this problem. U.S. Pat No. 5,183,612 discloses the deposition of the polymer frame onto a dummy windshield which has controlled dimensions. After the frame has cured, it is removed from the dummy windshield and then placed on the glass pane. Also, the polymer frame must be bonded to the glass pane when placed thereon. This process is cumbersome and results in duplicative operation as well as handling and storage problems for the cured polymer frame.
Another difficulty of prior art devices is that a secure seal to the pane is not always achieved. This can result in the escape of polymer from between the seal and the glass surface. Furthermore, movement between the die head and the pane becomes difficult if the seal between the die head and the pane is too strong. The present invention resolves these problems in a simple yet efficient manner.
SUMMARY OF THE INVENTION
The present invention relates to an apparatus for producing a shaped polymer frame on a plate having top and bottom main surfaces and a peripheral edge. The apparatus further comprises an extrusion die having a body which defines a plate-receiving recess for receiving the edge of the plate and portions of the main surfaces adjacent thereto; a first sealing ledge which is movable between (1) a retracted position which allows entry of the plate edge into the recess, and (2) an engaged position in contact with one of the main surfaces of the plate, wherein an open area is defined between the die body, sealing ledge and the plate in the shape of the polymer frame; and means for moving the plate relative to the extrusion die, where the moving means advances the edge of the plate through the recess to receive the shaped polymer frame on the edge and one of the main surfaces of the plate.
This embodiment also may include moving the first sealing ledge between the retracted and engaged positions in a direction which is essentially perpendicular to the main surfaces of the plate. The moving means preferably comprises spring means for biasing the first sealing ledge toward the engaged position and rod means for returning the first sealing ledge to the retracted position. The recess can include a first surface which is spaced from the plate and a second surface which contacts the plate on the surface opposite that which is contacted by the first sealing ledge in the engaged position, so that the polymer frame is provided on the edge and a portion of one main surface of the plate. Alternatively, the device can also include a second sealing ledge which is movable between (1) a retracted position which allows entry of the plate edge into the recess, and (2) an engaged position in contact with the other main surface of the plate, and the recess can include first and second surfaces which are spaced from the plate, so that the polymer frame is provided on the edge and a portion of each main surface of the plate.
Advantageously, the portions of the first sealing ledge and recess which contact the plate include a layer of an elastic material thereon to facilitate sliding movement upon the plate. Also, one or both of the sealing ledges can include an arcuate surface which assists in the formation of an arcuate portion for the polymer frame. The apparatus may also include a support wheel which travels along the surface of the plate and compensates for shape tolerances of the plate.
Another embodiment of the invention relates to an apparatus for producing a shaped polymer frame on a plate having top and bottom main surfaces and a peripheral edge. The apparatus further comprises an extrusion die having a one-piece body that defines a plate receiving recess for receiving the edge of the plate and portions of the main surfaces adjacent thereto. The plate receiving recess comprises first and second sealing ledges which slidingly engage the main surfaces of the plate. An open area is defined between the die body, sealing ledges and the plate in the shape of the polymer frame, and the sealing ledges provide a seal for the recess and facilitate sliding movement between the die body and the main surfaces. The apparatus also includes means for providing relative movement between the die and plate, such that the edge of the plate advances through the recess to receive the shaped polymer frame on the edge and at least one of the main surfaces of the plate.
In this embodiment, the portions of the sealing ledges that contact the plate include a layer of an elastic material, such as a thermoplastic, elastomeric, or thermoplastic coated elastomeric foam, thereon to facilitate the sliding movement. The elastic material has means for releasably securing the layer of elastic material to the sealing ledge to facilitate replacement of the layer. The releasable securing means preferably comprises a backing member for the elastic material. The backing member preferably includes a rib member for engaging a corresponding slot in the sealing ledge. Advantageously, the backing member is made of an engineering thermoplastic which has sufficient rigidity to retain the rib member in the slot, and the elastic material is secured to the backing member by a suitable adhesive. Furthermore, the extrusion die may include two channels for supplying polymer to the open area and means for independently regulating the flow of polymer in each channel to facilitate the extrusion of the polymer through the open area and onto the plate.
Yet another embodiment of the invention relates to a process for producing a shaped polymer frame on a plate having top and bottom main surfaces and a peripheral edge. The process comprises placing an extrusion die adjacent the plate edge, wherein the e
Cornils Gerd
Joeris Herbert
Kotte Rolf
Scholl Heinz
Eashoo Mark
Pennie & Edmonds LLP
Saint Gobain Vitrage
Silbaugh Jan H.
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