Glass manufacturing – Processes – With program – time – or cyclic control
Reexamination Certificate
1997-04-17
2001-09-04
Vincent, Sean (Department: 1731)
Glass manufacturing
Processes
With program, time, or cyclic control
C065S042000, C065S048000, C065S076000, C065S224000, C065S225000, C065S304000
Reexamination Certificate
active
06282922
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a method of producing molded glass bodies in accordance with the press-molding method, and to an apparatus particularly suited for executing this method.
Generally, the methods used for molding glass bodies are those which involve a plurality of press molds disposed with constant angular spacing on a rotatable machine table. After the press mold that is located under a filling apparatus, the so-called feeder, has been filled with a predetermined quantity of molten glass, the table is turned by the angular distance of two adjacent press molds, so that the one now containing the molten glass is positioned under a molding plug. The molding plug, which determines the interior shape of the molded glass body, is lowered into the mold and presses the molten glass into its actual exterior shape. During this procedure, the adjacent press mold, which is now located under the feeder, is filled with molten glass. After the minimum time required to complete the forming of the glass body, which is usually in a range of a few seconds, the molding plug is withdrawn from the press mold, the machine table is rotated again by the angular distance of two adjacent molds, and the cycle starts over.
The completed molded glass body remains in its press mold until it has cooled, through radiant emission and in particular through heat dissipation via the press mold, to the point at which it has solidified into a dimensionally-stable body. Typically, the time required for cooling significantly exceeds the pressing time for completing the molding procedure, so the molded glass body has to be cooled in the mold for the duration of several cycles. Therefore, the machine table must be equipped with at least enough press molds that the time required for transport from the pressing station to an unmolding station at least corresponds to the time required for cooling. The formula for the cooling time t
k
is:
t
k
=(
z
−1)
t
p
=zt
T
,
where z is the number of cycles, t
T
is the pressing time and t
P
is the time the rotating table requires to turn by an angular distance corresponding to the spacing between two adjacent molds. The capability of such a method, therefore, does not merely depend on the minimum pressing time required for molding the glass body, but it is substantially limited by the time required to cool the molded glass body until it solidifies.
Hence, a significant disadvantage of the procedure is that the capability of the method cannot be increased significantly, even with the use of more expensive and more efficient pressing drives, which allow for faster molding of the glass body.
SUMMARY OF THE INVENTION
The object of a method known in the related art, but not previously published, and an apparatus particularly suited for executing the method is to overcome these disadvantages.
In the method, the molding plug remains in contact with the molded glass body in the press mold following the actual pressing process. Thus, the contact with the metal molding plug allows an intensive heat transfer from the inside of the molded glass body to the molding plug, in addition to the dissipation of heat from the outside of the molded glass body via the press mold. Thus, in comparison to conventional methods, in which cooling air is often injected into the interior of the molded glass body, the molding plug effects a significantly more effective cooling of the inside of the molded glass body. This translates into a significant reduction of the time span over which the molded body must remain in the mold until at least the regions close to the surface have cooled to a temperature at which the molded body possesses sufficient inherent stability to be removed from the mold and transferred to a cooling station. Therefore, in this method, the mold is ready to be used in another pressing process after only a short time.
A disadvantage of these known methods is that a predetermined quantity of molten glass for the molded glass body is introduced into a separate filling station disposed upstream of the pressing station; on the one hand, the separate filling station increases the structural outlay for an apparatus suitable for executing this method, and, on the other hand, the time needed to transfer the mold from the filling station into the pressing station limits the maximum performance achievable with this method.
It is thus an object of the invention to develop a method with which this limitation of the capability of a glass-molding machine is eliminated without necessitating a significantly greater outlay for machinery. It is further an object of the invention to provide a glass-molding apparatus that is particularly suited for executing this method.
These objects are accomplished by the method and the glass molding apparatus disclosed in the application.
Because the predetermined quantity of molten glass is poured into the press molds located in the pressing station prior to the insertion of the molding plug, it is possible to omit the separate filling station disposed upstream of the pressing station with regard to the succession of method steps over time, which station is often a standard feature of conventional methods. Furthermore, the molded glass body can also be withdrawn from the press mold while the mold is located at the pressing station, eliminating the need for a mold transport. These measures not only decrease the structural outlay for an apparatus suitable for executing the method of the invention—for example by saving the mold needed thus far for the separate filling station—but also increase the capability of the method in this invention in comparison to conventional methods by saving the transport of the mold that has been filled with a predetermined quantity Of molten glass from the filling station to the pressing station, and possibly the transfer of the mold from the pressing station to the withdrawal station.
The molding plug is pivoted laterally, from its inoperative position for the filling process of the predetermined quantity of molten glass about an axis transverse to the lengthwise axis of the molding plug. This measure increases the space above the opening of the press mold that is available for the glass-filling process in the pressing station, which permits the apparatuses necessary for filling, even those of more voluminous structure, to be positioned problem-free above the opening of the mold. Thus, it is possible to avoid the use of special filigree apparatuses for filling, which would mean an increased structural outlay and greater susceptibility to failures. In addition, withdrawing the molded glass body from above is manageable without necessitating lifting the plug out of the mold by a large stroke to create the necessary free space, which would negatively influence the capability achievable in this method.
With a low structural outlay and particular reliability, the mold can be filled with the predetermined quantity of molten glass after rotation of the molding plug if a feeding chute connected by the so-called feeder is rotated from an initial position that permits the insertion of the molding plug into the press mold into a position in which the open end of the supply line communicates with the mold opening, with the chute rotating back to its initial position after the filling process is complete.
The capability of the method according to the invention can be greatly increased if the predetermined quantity of molten glass is concurrently supplied to a plurality of molds located in the pressing station prior to the insertion of the molding plug, and glass bodies are pressed from molten glass with a corresponding number of molding plugs. The increase in capability is achieved with a relatively low additional structural outlay, involving only the additional molding plugs, press molds and devices for filling the press molds with the predetermined quantity of molten glass.
A modification of the method of the invention for a possible application is also disclosed. In this embodiment, partial molded bodi
Poting GmbH & Co. KG
Vickers Daniels & Young
Vincent Sean
LandOfFree
Method of producing molded glasses bodies according to the... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of producing molded glasses bodies according to the..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of producing molded glasses bodies according to the... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2504442