Glass manufacturing – Preform reshaping means – Sheet bending mold
Reexamination Certificate
1999-11-30
2002-04-02
Colaianni, Michael (Department: 1731)
Glass manufacturing
Preform reshaping means
Sheet bending mold
C065S100000, C065S101000, C065S102000, C065S106000, C065S185000, C065S245000, C065S253000, C065S256000, C065S370100, C198S787000, C198S826000, C198S827000, C198S824000, C198S780000, C193S0350SS, C193S037000, C492S002000, C492S006000, C492S042000, C492S043000, C492S050000
Reexamination Certificate
active
06363753
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to an apparatus for manufacturing a bent or curved glass sheet, and more particularly to such a curved glass manufacturing apparatus which is equipped with improved bending and conveyor units. It also relates to a bending roll mechanism and a conveyor roll mechanism used in the bending unit and the conveyor unit, respectively.
2. Description of the Related Art
Various curved glass manufacturing apparatuses including a bending section and a conveyor system are known. Examples of such known apparatuses are disclosed in Japanese Patent Laid-open Publication No. SHO 54-85217 entitled “Method and Apparatus for Shaping Glass Sheets by Roll Forming”, Japanese Patent No. 2690766 entitled “Conveyor Roll Structure”, Japanese Patent Laid-open Publication No. HEI 3-150232 entitled “Method and Apparatus for Bending Glass Sheets”, Japanese Patent Laid-open Publication No. HEI 3-174334 entitled “Machine and Process for Manufacturing Curved Glass Sheets”, and Japanese Patent Laid-open Publication No. HEI 4-275929 entitled “Method and Apparatus for Bending Glass Sheets”.
The apparatus shown in Japanese Patent Laid-open Publication No. SHO 54-85217 includes a bending section having a series of horizontally arranged upper forming rolls of convex cross-sectional shape and a series of horizontally arranged lower forming rolls of concave cross-sectional shape disposed in vertical juxtaposition so that a flat glass sheet, as it is passed between the upper and lower forming rolls, is bent into a desired curvature.
The upper and lower forming rolls are segmented so as to reduce the difference in circumferential speed between a large-diameter portion and a small-diameter portion of each forming roll.
However, since the difference in circumferential speed cannot be fully taken up or canceled by the segmented structure of the forming rolls, a mark or scar may be produced on opposite surfaces of the glass sheet due to slip occurring between the surfaces of the glass sheet and circumferential surfaces of the upper and lower forming rolls.
Additionally, since these parts of the forming rolls which correspond in position to parting lines between the adjacent segmented pieces do not contact with the surfaces of glass sheet during bending operation, the glass sheet while being bent by such forming rolls is likely to be strained or distorted.
Furthermore, due to the segmented structure, the forming rolls of the known apparatus is not easily adaptable to the manufacture of a curved glass sheet with different curvature.
Japanese Patent No. 2690766 discloses a conveyor roll which, as shown here in
FIG. 25
, includes a core member
101
bent into a desired curvature, and a helical coil spring member
102
rotatably wound around the core member
101
. By rotating the spring member
102
, glass sheets
103
which have been bent into a desired curvature are conveyed to a subsequent processing section.
To secure smooth rotation of the spring member
102
around the core member
101
, a certain clearance S must be provided between the core member
101
and the spring member
102
. However, especially when the core member
101
is used with a relatively small curvature, the clearance S may allow the spring member
102
to become eccentric to the core member
101
, thus producing up-and-down movement or pitching of the glass sheets
103
during conveyance along a succession of such conveyor rolls
100
. Due to the pitching, very small undulations are formed on opposite surfaces of the conveyed curved glass sheet, which may produce distortion or warping of image when an image is formed on such undulated surface of the curved glass sheet
103
by light either reflected from the undulated glass sheet surface or transmitted through the glass sheet
103
.
Additionally, to cope with the conveyance of glass sheets of different curvatures, replacement of the core member
101
with another core member is unavoidable. This requirement may result in a considerably reduced productivity of the curved glass manufacturing apparatus.
SUMMARY OF THE INVENTION
The present invention is conceived to solve the foregoing problems associated with the prior art.
A more specific object of the present invention is to provide a curved glass manufacturing apparatus which is capable of manufacturing a curved glass sheet with high qualities and is readily adaptable to the manufacture of various curved glass sheets of different curvatures.
A further object of the present invention is to provide a curved glass manufacturing apparatus having a bending unit which is capable of bending a flat glass sheet into a desired curvature without producing a slip between forming rolls and the glass sheet and is readily adaptable to the manufacture of various curved glass sheets of different curvatures.
Another object of the present invention is to provide a curved glass manufacturing apparatus having a conveyor unit which is capable of achieving a reliable conveyance of curved glass sheets by virtue of little eccentricity of the conveyance roll and is readily adaptable to the conveyance of various curved glass sheets of different curvatures.
According to a first aspect of the present invention, there is provided a curved glass manufacturing apparatus comprising at least one roll-forming unit composed of at least one upper forming roll mechanism and at least one lower forming roll mechanism cooperating with the upper forming roll mechanism to form a heated flat glass sheet into a curved glass sheet of a desired curvature. Each of the upper and lower forming roll mechanisms includes a forming roll having a resilient rod covered with a cover member except opposite end portions thereof, a pair of support members rotatably supporting the opposite end portions of the resilient rod while allowing the resilient rod to tilt about the support members, a bending unit coupled with at least one of the opposite end portions of the resilient rod for applying to the at least one end portion an external force tending to flex the forming roll into either an upwardly arched configuration or a downwardly arched configuration, and at least one backup roller unit being in rolling engagement with the forming roll to maintain the arched configuration of the forming roll.
Each of the upper and lower forming roll mechanisms may further include a drive source coupled with the other end portion of the resilient rod to rotate the forming roll.
Preferably, the resilient rod is composed of an elongated core member of resilient material, a plurality of resilient strands laid longitudinally on a peripheral surface of the core member in close juxtaposition around the core member, and a helical coil spring wound around the resilient strands to tightly bind together the resilient strands and the core member.
The cover member may be a seamless tube having a knit structure formed of a glass fiber, ceramic fiber, metal fiber, aramid fiber or the combination thereof. Alternatively, the cover member may be a continuous tape wound around the resilient rod and having a woven structure formed of the same material as the seamless knit tube.
Preferably, the support members each include a fixed housing having a spherical hole, and a spherical segment member pivotally received in the spherical hole and rotatably supporting one of the opposite end portions of the resilient rod.
In one preferred form, the bending unit includes a tubular holder pivotally supported by one of the support members and having an axial blind hole in which the one end portion of the resilient rod is slidably and rotatably received, and an adjustment screw threaded through a closed end of the tubular holder into the axial blind hole and adapted to be turned to displace the one end portion of the resilient rod in an axial inward direction for causing the forming roll to flex in the arched configuration. The bending unit may further include a compression coil spring and a steel ball in the axial blind hole of the tubular holder and disposed between
Kuramoto Shunji
Yoshizawa Hideo
Colaianni Michael
Nippon Sheet Glass Co. Ltd.
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