Glass manufacturing – With repair – assembly – or disassembly means for apparatus – To replace worn or damaged parts
Reexamination Certificate
1999-04-07
2001-04-10
Vincent, Sean (Department: 1731)
Glass manufacturing
With repair, assembly, or disassembly means for apparatus
To replace worn or damaged parts
C292S046000, C292S256690, C292S257000
Reexamination Certificate
active
06212910
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a feeder tube assembly for a feeder bowl of a glass melting furnace forehearth. More particularly, this invention relates to a clamp down system for releasably clamping a feeder tube in its operating position.
2. Description of the Prior Art
U.S. Pat. No. 5,718,741 (Hull et al.), which is assigned to the assignee of this application, the disclosure of which is incorporated herein by reference, discloses a forehearth for cooling a stream of molten glass as it flows from a glass melting furnace to a forming machine for forming the molten glass into finished products, for example, hollow glass containers of the type widely used in packaging various food, beverage and other products. In the arrangement of the '741 Patent, and in a variety of other types of forehearths, molten glass flows downwardly through an opening, or a plurality of openings, in the bottom of a feeder bowl at an end of the forehearth that is remote from the end into which molten glass from the melting furnace flows.
To control the flow of molten glass from a forehearth feeder bowl, a vertically extending, refractory feeder tube is provided with its lowermost end immersed in the feeder bowl to a level slightly above the inside surface of the bottom of the feeder bowl and surrounding the opening(s) at the bottom of the feeder bowl, and the ceramic tube is caused to rotate slowly during the operation of the forehearth to ensure a proper mixing and temperature uniformity of the molten glass flowing from the feeder bowl. A feeder bowl refractory tube with a tube drive system of this general type is disclosed in U.S. Pat. No. 5,660,610 (DiFrank), which is also assigned to the assignee of this application, the disclosure of which is also incorporated by reference herein. Other glass forehearth feeder bowl feeder tube arrangements are described in U.S. Pat. No. 5,693,114 (Scott), U.S. Pat. No. 4,514,209 (Mumford), and U.S. Pat. No. 4,478,631 (Mumford), the disclosure of each of which is also incorporated by reference herein.
From time to time during the operation of a glass manufacturing system of a type employing a forehearth feeder bowl feeder tube of the type described above it is necessary to remove the feeder tube and/or the feeder bowl for repair or replacement. In the case of the replacement of the feeder bowl, the feeder tube must also be swung horizontally out of the way of the feeder bowl as well as being lifted vertically so that its lower edge clears the upper extent of the feeder bowl. It is also necessary from time to time to be able to adjust the height of the feeder tube. As a feeder tube of this type is quite massive, very large forces are required to lift it from its operating position. Heretofore, counterweighted lift mechanisms were employed for this purpose, and these mechanisms typically employed gear boxes with considerable backlash, thus making precise positioning and motions of the feeder tube very difficult. Moreover, in these arrangements, precise adjustment of the position of the feeder tube in a horizontal plane, in X and/or Y directions, was difficult to achieve in that the horizontal motions of the counterweight lift mechanisms could not be isolated along X or Y axes. Further, counterweighted lift mechanisms are cumbersome because of the dead weights employed in them, and the vertical feeder tube slide supports are subject to wear during up and down tube adjustments, which can impart a wobbling motion to the tube support system and thereby lead to undesired glass gob weight variation in a feeder bowl used in conjunction with a glass container forming machine of the individual section (I.S.) type. Also, from time to time, it is necessary to replace a feeder bowl itself. In the prior art, this required removal of the entire feeder tube mechanism itself. A feeder tube in apparatus of the type described is releasably held in place by a circumferentially spaced apart plurality of clamps. Heretofore, it has been difficult to release such clamps, which typically involved threaded members, because of the tendency of such members to corrode in the high temperature environment of a feeder tube installation and the need for workers to wear temperature resistant gloves during this procedure, gloves that are quite bulky
SUMMARY OF THE INVENTION
According to the present invention of the aforesaid co-pending U.S. patent application, the aforesaid and other problems associated with prior art glass forehearth feeder bowl feeder tube lift systems are avoided by a feeder tube lift system that employs a single, multiple shaft, servo motor operated, ball screw lift mechanism of sufficient capacity to sustain a cantilevered feeder tube support mechanism with minimal deflection. Such a lift mechanism involves no, or very little, backlash in its motions, thereby permitting precise control of the elevation of the lift tube in the feeder bowl, which is important in achieving accurate control of glass gob weight in an I.S. machine glass container manufacturing operation.
The feeder tube lift mechanism of the present invention is also capable of true isolated adjustments in a horizontal plane, both along X and Y axes, and it can be moved without slide wear, thereby avoiding introduction of wobbling motion to the tube support system. The servo motor powered ball screw lift mechanism of the present invention is lubricated by a lubricant that is recirculated within a closed system to ensure long life for bearings of the mechanism and the ball roller nut, and avoiding lubricant leakage and the need for lubricant replacement.
According to the invention of the aforesaid co-pending U.S. patent application, and according to an improved version of such invention according to this patent application, there is provided an improved clamp for releasably clamping a feeder tube engaging clamping ring in its clamping position against a flange of the feeder tube while the feeder tube is in its operating position with respect to the rotatable support. Each such clamp has a variable radius cam that is rotatable about a radially extending horizontal axis to make secure contact with the clamping ring regardless of the elevation of the feeder tube, but which is capable of being swung out of interfering contact with the feeder tube to permit the feeder tube to be removed for repair or replacement after first removing the clamping ring used to engage a flange of the feeder tube.
Accordingly, it is an object of the present invention to provide an improved clamp down system for clamping a feeder tube of the type employed in a glass forehearth feeder bowl. More particularly it is an object of the present invention to provide a clamp down-system that is rapidly releasable in that it does not require threaded fasteners in its design or installation.
For further understanding of the present invention and the objects thereof, attention is directed to the drawing and the following brief description thereof, to the detailed description of the preferred embodiment and to the appended claims.
REFERENCES:
patent: 1532514 (1925-04-01), Raynes
patent: 1760254 (1930-05-01), Peiler
patent: 1843248 (1932-02-01), Soubier
patent: 1852218 (1932-04-01), Peiler
patent: 3239326 (1966-03-01), Tyner
patent: 4478631 (1984-10-01), Mumford
patent: 4514209 (1985-04-01), Mumford
patent: 4551163 (1985-11-01), Duga et al.
patent: 4554000 (1985-11-01), Suomala et al.
patent: 5693114 (1997-12-01), Scott
Owens-Brockway Glass Container Inc.
Vincent Sean
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