FR2560592A1 - Process and device for preforming a drop of glass and their application to the pressing of glass articles - Google Patents

Abstract

Device for preforming a drop of glass, to be inserted between a standard feed apparatus and a usual pressing mould. It consists essentially of a trolley 6 driven in a to-and-fro motion above the mould 5 and equipped, on the one hand, with an upper entry hopper 7 capable of receiving a compact dose of molten glass 2 originating from the feed 1 and, on the other hand, lower exit rolls 8 suitable for rolling the said dose of molten glass to deliver an elongate strip 2b thereof which is spread at the bottom of the mould 5 in step with the travel of the trolley 6. Application to the manufacture of glass articles by pressing.

Description

 Conventional methods allow a wide variety of glassware to be made by pressing a drop of glass commonly called parison.

 However, there are annoying manufacturing restrictions imposed by the natural configuration of the drop that comes to deposit at the bottom of the molds the usual feeding devices and more precisely by its elongation coefficient or length / thickness ratio. In fact, this natural configuration in turn limits the length / thickness ratio of the articles that can be produced directly by pressing a drop, especially when they are relatively thin.

 However, there is currently a demand on the market for glass articles having a coefficient greater than 3 for a twist thickness of 3 mm, for example for automobile headlights. The manufacturer is therefore led to resort to other execution methods, generally more complex, slow and expensive.

 The present invention allows dty to escape by the implementation of an automatic process which is compatible with standard drop delivery and pressing devices, which implies low investment and production costs.

 According to the invention, by operating at the usual feeding and pressing station, the drop of glass is spread in the mold to the desired size and is pressed in a conventional manner to obtain the finished product requiring no further finishing. This spreading can be performed from a conventional feed by laminating the drop of glass, then spreading it longitudinally on the bottom of the mold, before pressing.

 The present invention also extends to a device for preforming the drop of glass, intended to be inserted between any suitable supply means and the mold: according to one embodiment of the invention, this device consists essentially of '' a carriage driven back and forth below the mold and equipped on the one hand with an upper inlet hopper suitable for receiving a compact dose of molten glass from the feed and d on the other hand, lower outlet rollers suitable for laminating said dose of molten glass to deliver an elongated strip which spreads out at the bottom of the mold as the carriage travels.

 The description which follows with reference to the appended drawings, given by way of nonlimiting example, will make it clear how the invention can be implemented.

FIG. 1 is a schematic elevational view illustrating the operation of a device according to the present invention, in two suc censive positions,
Figures 2 and 3 are partial schematic plan views, respectively at the start and end of the carriage travel.

 There is shown in the drawings on the one hand a standard feeding device 1 delivering a compact dose of molten glass 2 conveyed by a chute 3 and on the other hand a horizontal rotary pressing table 4 on which are distributed individual molds 5 .

 In accordance with the present invention, there is interposed between the feed device 1 and the pressing table 4 a carriage 6 driven in a reciprocating movement in the radial direction F relative to the rotary table 4, the stroke of the carriage 6 being advantageously adjustable. This carriage is equipped with an upper inlet hopper 7 with graphite walls, which opens downward onto rolling rollers 8 whose axis is perpendicular to F and whose spacing is also advantageously adjustable; in a position of the carriage 6, for example at the end of its travel remote from the axis of rotation of the table 4, the hopper 7 is located directly above the outlet of the feed chute 3 to receive the dose molten glass 2 delivered by the device 1. This dose 2a is laminated by the rollers 8 and leaves therefrom in a strip 2b which is deposited at the bottom of a mold 5 in the form of an elongated wafer 2c.

 We can then rotate the table 4 with an angular step and proceed to pressing the glass wafer in Sa.

 It should be noted that the shape of the wafer 2c depends on several parameters: configuration of the hopper 7, spacing of the rollers 8, speed of rotation of the latter, speed of translation of the carriage 6, starting point and length of travel of this one.

 It goes without saying that the embodiment described n1 is only an example and that it could be modified, in particular by substitution of technical equivalents, without departing from the scope of the invention.

Claims (4)

 1. A process for preforming a drop of glass from a standard feeding device and intended for a pressing mold, characterized in that the glass drop (2) is spread in the mold (5 ) to the desired size and it is pressed in a conventional manner to obtain the finished product.  2. Method according to claim 1, characterized in that quton performs the spreading of the drop of glass (2) by rolling it and then spreading it longitudinally on the bottom of the mold (5) before pressing.  3. Preforming device for implementing the method according to claim 1 or 2, intended to be interposed between a feeding device and a mold, characterized in that it consists essentially of a carriage (6) animated with a back and forth movement above the mold (5) and equipped on the one hand with an upper inlet hopper (7) suitable for receiving a compact dose of molten glass (2) coming from the mentation (1) and on the other hand of lower outlet rollers (8) suitable for laminating said dose of molten glass in order to deliver an elongated strip (2b) which spreads out at the bottom of the mold (5) progressively of the carriage stroke (6).  4. Application of the method according to claim 1 or 2 or of the device according to claim 3 to the manufacture by pressing of glass articles,