FORMATION OF GLASS ARTICLES

Abstract: A glass forming apparatus of the press-and-blow type comprising a press moulding station (5) and a blow moulding station (18), the apparatus being provided with a transfer means (12) adapted to transfer a hollow blank from the press moulding station (5) to the blow moulding station (18) and to rotate the hollow blank about its vertical axis, and/or provided with a retractable gob deflector (11a) adapted to receive a glass gob from a gob feeder and to deflect the glass gob into the blank mould (5), and/or provided with a blow mould (18) comprising two or more mould parts (18a, 18b) and adapted to open or close by relative linear movement of the two or more mould parts (18a, 18b).

Description: FORMATION OF GLASS ARTICLES FIELD OF THE INVENTION This invention relates to the formation of glass articles, and more particularly to a novel machine for producing glass articles which has improved versatility and is of lower cost. BACKGROUND TO THE INVENTION Glass tableware is commonly manufactured on a paste mould machine of the press-and-blow or blow-and-blow type. The machine comprises a plurality of heads which are continuously rotated on a carousel. Each head comprises a blank mould and a blow mould, and produces a moulded article per revolution of the carousel. The machine uses a gob single feeder, which feeds each of the one-piece blank moulds as they travel by. Delivery is accomplished by an oscillating delivery chute which travels with each blank mould for a short distance, then reverses and falls back to travel again with the succeeding blank mould. As each blank mould passes the gob feeder chute, a gob of glass falls into the one-piece blank mould. The blank mould then moves on and rises until it is seated in a neck ring. In the press-and-blow type machine, a plunger is lowered through the neck ring to press the glass gob into the shape of a tapered glass parison, within the solid iron blank mould. The blank mould and plunger retract to their original positions leaving the parison suspended by the neck ring which is rotated in a horizontal plane. The surface of the parison re-heats, and the parison itself elongates, until it assumes a shape suitable to enter the blow mould. The blow mould is in two halves which are pivotally mounted and can rotate about vertical axes from an open to a closed position. Each of the blow moulds is lined with a cork paste, and wetted by water sprays. The water is shut off, the two halves of the blow mould rotate to close the mould, and blowing occurs as the parison is still rotating. When blown, the glass article cools until the blow mould opens and tongs remove the glass article from the neck ring. Finally the top or moil is burnt off to produce the finished article. It will be apparent that the paste mould machine is complex and extremely expensive, but it has the advantage that articles with a high surface finish are produced without any seam marks. Nevertheless the investment required in such machines has limited their use to the larger glass manufacturing companies. Another disadvantage of the paste mould machine is that the blank moulds travel in both a horizontal and a vertical plane, respectively for receiving the glass gob from the feeder and for pressing the parison. The possibility of several degrees of freedom increases the risk that wear in the handling equipment will lead to decreased accuracy in the pressing of the parison. In addition, because the two halves of the blow mould are pivotally mounted, in a "clam-shell" type arrangement, it is possible for the parison to become pinched between the two halves of the blow mould as they close, if the parison is not accurately sized and positioned. The clam-shell operation of the blow mould also limits the size of ware which can be produced, and requires a relatively large amount of space for the moving parts. Another known machine, particularly for producing bottles and jars, is the IS (independent section) machine in which each section is independent and comprises a complete bottle or jar manufacturing unit. The sections are lined up side-by-side, and, as there is no rotation, the moulds have only to open and close. Each section has it's own gob delivery system, which is controlled by the section timing mechanism. In operation, the blank mould is moved horizontally until it is positioned under a stationary guide funnel which is connected to the gob delivery system. The gob drops through the guide funnel into the blank mould and settles at the bottom of the mould. The mould is then retracted and an air-operated plunger rises up from the bottom of the mould and pushes the glass into an inverted parison. As the blank mould opens, the inverted parison is held in a neck ring attached to a transfer arm. The neck ring swings the parison 180 degrees in a vertical plane to a position over a blow mould which is in the act of closing. The blow mould is again in two halves, pivotally mounted and rotatable about vertical axes between an open and a closed position in a clam-shell type arrangement. Just as the blow mould closes all the way, the neck ring opens, releasing the parison and allowing it to drop into the correct position within the blow mould. The neck ring returns to its original relationship with the blank mould and the mould cycle is repeated. During transfer, the parison is held by its top or finish in the neck ring, but does not otherwise touch the mould metal, allowing re-heat of the skin or surface of the parison to take place. The parison elongates after it is inverted, and ultimately the hollow glass article is blown by a blow-head situated on the top of the blow mould. After cooling, the hollow glass article is removed by take-out tongs. The IS machine can have fewer sections than there are heads of the paste mould machine, and the number of sections can be expanded as production requirements increase. Nevertheless the gob delivery system is complicated, and becomes more so with an increasing number of sections. The IS machine also has the same disadvantages as the paste mould machine in that wear in the blank mould moving parts can lead to inaccurate pressing of the parison, and the clam-shell arrangement of the blow mould halves can give rise to pinching of the parison. In addition, the production rate for an individual section is dependent upon the blow moulding cycle, which is substantially longer than the press moulding cycle. A further disadvantage is that the IS machine does not rotate the parison and leaves a seam line from the press moulding stage. The surface quality of an article produced on the IS machine is also usually inferior to that of the paste mould machine. It is apparent from the above that there is a need for a machine for the production of hollow glass articles which can achieve the surface quality of the paste mould machine and the versatility of the IS machine but with a lower capital expenditure, and which can provide an improved accuracy in pressing and blowing of the parison. SUMMARY OF THE INVENTION According to one aspect of the present invention there is provided a glass forming apparatus of the press- and-blow type comprising a press moulding station and a plurality of blow moulding stations. In another aspect, the invention provides a glass forming apparatus of the press-and-blow type comprising a press moulding station, a blow moulding station, and a transfer means adapted to transfer a hollow blank from the press moulding station to the blow moulding station and to rotate the hollow blank about its vertical axis. In still another aspect, the invention provides a glass forming apparatus of the press-and-blow type, which is provided with a retracting gob deflector. In a further aspect, the invention provides a glass forming apparatus of the press-and-blow type, in which the blow mould opens and closes by relative linear movement of the two halves thereof. In a first preferred aspect, the invention provides a glass forming apparatus for the production of hollow glass articles which comprises: a first station comprising a blank mould and a plunger co-operable therewith adapted to form a glass gob into a hollow blank, a transfer means adapted to transfer the hollow blank from the first station to a second station, and to rotate the hollow blank about its vertical axis whilst it is being transferred from the first station to a second station, a plurality of second stations each adapted to receive a hollow blank from the first station and comprising a blow mould and blowing means co-operable therewith to form the hollow blank into a blow moulded hollow glass article. In a second preferred aspect of the invention, there is provided a glass forming apparatus for the production of hollow glass articles which comprises: a first station comprising a blank mould and a plunger co-operable therewith adapted to form a glass gob into a hollow blank, and a retractable gob deflector adapted to receive a glass gob from a gob feeder and to deflect the glass gob into the blank mould, the gob deflector being retractable from a first gob deflecting position in which it is situated between the blank mould and the plunger to a second position in which the gob deflector does not interfere with the movement of the blank mould or the plunger in the formation of the hollow blank. In a third preferred aspect of the invention, there is provided a glass forming apparatus for the production of hollow glass articles which comprises: a first station comprising a blank mould and a plunger co-operable therewith adapted to form a glass gob into a hollow blank; a transfer means adapted to transfer the hollow blank from a first station to a second station; and a second station adapted to receive a hollow blank from the first station and comprising a blow mould and blowing means co-operable therewith to form the hollow blank into a blow moulded glass article; the blow mould comprising two or more mould parts and being adapted to open or close by relative linear movement of the two or more mould parts. The glass forming apparatus of the invention may be used to produce hollow glass articles such as, for example, glasses, tumblers, mugs, cups and other tableware. The apparatus preferably also comprises a gob feeder, which can, for example, convey a glass gob from a forehearth to the blank mould via a delivery chute and the gob deflector. The gob deflector is preferably in the form of an elongate downwardly depending metal channel which is positioned, in gob deflecting operation, such that its lower end is substantially vertically above the open mouth of the blank mould. In this position, it would interfere with the relative vertical movement of the blank mould and the plunger in the press moulding cycle. In accordance with the second preferred aspect of the invention, therefore, the gob deflector moves, preferably in a horizontal direction, to a position in which it cannot interfere with the vertical travel either of the plunger or of the blank mould. The blank mould is preferably of unitary construction and mounted for reciprocal vertical movement. The plunger is preferably arranged vertically above the blank mould and also arranged to have reciprocal vertical movement. Preferably neither the blank mould nor the plunger are required to move in a horizontal plane in normal operation. This removes a degree of freedom of movement for the mould and plunger and improves the accuracy of the pressing of the glass blank or parison. The transfer means preferably comprises a neck ring, which forms part, usually the top, of the blank mould and receives a portion of the hollow glass blank or parison which is formed by the action of the plunger on the glass gob. When the blank mould is opened to release the blank, a top portion of the blank, known as the moil, is retained within the neck ring. The neck ring is thereby able to convey the blank suspended from the moil to the blow mould. The neck ring may be in two or more, and preferably four, sections. The transfer means transports hollow blanks or parisons from the blank mould to two or more blow moulds. It may comprise one or more, and preferably two or more elongate transfer arms, which are reciprocally rotatable in a horizontal plane above the moulds. Preferably the transfer means rotates the blank or parison about the vertical axis thereof whilst transferring it from the blank mould to the blow mould. Preferably this rotation is achieved by rotating the neck ring about its vertical axis. The time taken for the transfer is preferably sufficient to allow re-heating of the blank or parison to take place. In accordance with the third preferred aspect of the invention, the blow mould comprises two or more parts and is adapted to open and close by relative linear movement of the said mould parts. Preferably the blow mould is in two halves and the mould is opened and closed by movement of the two halves on linear slides. Preferably the blow mould is a paste mould which, for example, can be lined with a cork paste and wetted with water sprays. BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of a glass forming apparatus according to the invention will now be described with reference to the accompanying Drawings in which: Figure 1 shows a glass forming apparatus according to the invention in plan view; Figure 2 shows a sectional side elevation of the apparatus of Figure 1, taken along the line A-A illustrating the gob deflector in its retracted position; Figure 3 shows a sectional side elevation of the apparatus of Figure 1, taken along the line A-A, with the gob deflector in its extended position; Figure 4 shows the transfer mechanism of the apparatus of Figure 1, including the neck ring assembly, in plan view; and Figure 5 shows the transfer mechanism of Figure 4 in sectional side elevation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring firstly to Figures 1 and 2, the glass forming apparatus, illustrated generally at 1, comprises a base 2 and a frame 3. Mounted on the frame 3 is a control panel 4 for controlling and synchronising the various actions of the machine components. In an alternative design (not shown) the control panel can be free-standing, or separately mounted. The press mould station comprises a one-piece blank mould 5, having a contoured internal surface 6, which can be raised and lowered in a vertical plane by means of a blank mould raising cylinder 7. Co-operating with the blank mould 5 is a plunger 8, mounted upon a press cylinder 9, which is itself reciprocally mounted upon a vertical rod 10. The plunger 8 is positioned centrally above the blank mould 5, and both the plunger and the blank mould can travel only along a central vertical axis and are not permitted any horizontal or sideways movement in normal operation. This greatly obviates any inaccuracies, in alignment caused by wear of moving parts. Leading from the gob delivery system (not shown) is a delivery chute 11 comprising an inclined open channel which is fixed in position above and to one side of the blank mould 5 so that it does not interfere with the vertical travel of the plunger 8 or the blank mould 5. Beneath the delivery chute is a retractable gob deflector 11a, which comprises a curved downwardly depending open channel. The deflector 11a is illustrated in Figure 2 in its retracted position, in which it does not obstruct the vertical travel of the plunger 8 or the blank mould 5. The gob deflector 11a can travel between the retracted position illustrated in Figure 2 and an extended position illustrated in Figure 3. In the extended position, the top of the gob deflector channel lib connects with the bottom lie of the delivery chute 11, and the bottom of the gob deflector channel lid is positioned over the blank mould 5. The gob deflector is moved between its retracted and extended portions by a cylinder (not shown). The apparatus is provided with a pair of transport arm mechanisms 12 and 13 which are mounted upon vertical axles 14 and 15 about which they can be reciprocally rotated in a horizontal plane. Each transport arm mechanism carries a neck ring assembly 16, 17 for the transporting of the glass blank or parison 33 from the press mould 5 to the blow moulds 18 and 19. The blow moulds 18, 19 each comprise two halves 18a, 18b and 19a, 19b, which are slidably mounted upon carriage mechanisms 20 and 21, each of which incorporates a mould opening and closing mechanism activated by cylinders 22 and 23. The carriage mechanisms 20 and 21 comprise sliders 20a, 20b, 21a and 21b which are supported for lateral movement on elongate horizontally directed guide channels 20c and 21c. The blow moulds are each provided with a blow head 24, and an optional foot forming cylinder 25. The construction of the transport arm mechanism 12 is illustrated in more detail in Figures 3 and 4. Transport arm mechanism 13 is of course an identical mirror image. The vertically arranged axle 14 is mounted upon a plinth 26 which is rotatable by means of an oscillator 27. The neck ring assembly 16 comprises a neck ring 28, which is divided into four quarters, connected to four pivotally mounted arms, of which two, 29 and 30, are shown. At their ends remote from the neck ring the arms are in contact with a cam ring 31, and the neck ring assembly is relatively rotatable with respect to the cam ring, by which means the neck ring can be opened and closed. The neck ring 28 is provided with a recessed lip 32 and the entire neck ring assembly can be rotated by a rotation mechanism comprising the drive gears 33 and rotation air motor 34. In operation, the gob deflector 11a is moved to its extended position above the blank mould 5 and a gob from the gob delivery system enters the delivery chute 11 and is delivered to the blank mould 5 via the gob deflector 11a. The gob deflector 11a is then retracted and the blank mould 5 raised by the action of the cylinder 7 until it mates and engages with a four-part neck ring (in this case 17) of one of the transport arm mechanisms (in this case 13). The plunger 8 is then lowered together with press cylinder 9, until it passes through the neck ring, and the press cylinder 9 then operates to force the plunger into the blank mould, pressing the glass gob against the internal wall 6 of the blank mould 5, and forming the glass gob into a blank or parison within the blank mould. During the pressing operation some of the glass is forced up into the neck ring and is held in the recessed lip 32 thereof. After the blank or parison has been formed, the blank mould 5 is lowered, and the plunger 8 is raised, leaving the blank or parison suspended by the neck ring 28. As soon as the mould has disengaged, rotation of the neck ring 28 about its vertical axis is commenced by means of the drive gears 33 and rotation air motor 34. The speed of rotation can be varied and if desired rotation can be stopped for still blowing. Once the mould and plunger have become completely disengaged, the transport arm mechanism 13 is rotated, in a horizontal plane about the rotatable axle 15, until the neck ring assembly 17 is in register with the blow mould 19. This can be seen more clearly in Figure 2 in which the parison 33 is shown suspended between the two halves of the blow mould 18a and 18b. Next the blow mould is closed around the blank or parison 33 by relative lateral movement of the mould halves 18a and 18b. By closing the blow mould by relative lateral movement of the mould halves, rather than by pivotal movement, the mould halves are able to separate by a greater distance which facilitates the production of larger ware if desired. The opening and closing mechanism can also be made extremely compact. In the next moulding step, the blow head 24 is lowered until it mates with the neck ring assembly 16. The blank or parison is then blown and at the same time the foot is formed by the foot forming cylinder 25. As will be appreciated from the above description, the parison once pressed is transferred and blown without leaving the transport arm mechanism. When the hollow glass article has cooled sufficiently, the blow mould is opened and the transport arm mechanism 13 is rotated to the eject position, illustrated by broken line 35 in Figure 1. In this position the neck ring is opened and the moulded article ejected. In a modified operation of the apparatus, the transport arm mechanism 13 can be rotated from the press mould directly to the eject position 35, and the neck ring opened to release the press moulded parison as a finished article. This can be useful in adapting the apparatus to produce press moulded articles which do not need a blow moulding operation. Alternatively the blow mould 18 can be replaced by a system of cooling ducts so that the press moulded parison can be cooled at the blow moulding station without blow moulding and then moved to the eject position 35 for release. It can be seen that the invention provides a highly cost effective apparatus for the production of hollow glass articles, for example, by permitting a press mould to feed two or more blow moulds. The apparatus can be of modular construction, and is thereby capable of expansion by the addition of further stations in order to increase production capacity. Several blow moulding stations can be fed from a single press moulding station until a capacity limit is reached at which point further press moulding and blow moulding stations need to be added. The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. CONFIRMAΗON COPY Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. The invention is not restricted to the details of the foregoing embodiment(s). This invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. CONFIRMAΗON COPY

Claims: CLAIMS 1. A glass forming apparatus for the production of hollow glass articles which comprises: a first station comprising a blank mould and a plunger cooperable therewith adapted to form a glass gob into a hollow blank, a transfer means adapted to transfer the hollow blank from the first station to a second station, and to rotate the hollow blank about its hollow axis whilst it is being transferred from the first station to a second station; and a plurality of second stations each adapted to receive a hollow blank from the first station and comprising a blow mould and blowing means cooperable therewith to form the blank into a blow moulded glass hollow article. 2. A glass forming apparatus for the production of hollow glass articles which comprises: a first station comprising a blank mould and a plunger cooperable therewith adapted to form a glass gob into a hollow blank, and a retractor gob deflector adapted to receive a glass gob from a gob feeder and to deflect the glass gob into the blank mould, the gob deflector being retractable from a first gob deflecting position in which it is situated between the blank mould and the plunger to a second position in which the gob deflector does not interfere with the movement of the blank mould or the plunger in the formation of the hollow blank. 3. A glass forming apparatus for the production of hollow glass articles which comprises: a first station comprising a blank mould and a plunger cooperable therewith adapted to form a glass gob into a hollow blank; a transfer means adapted to transfer the hollow blank from a first station to a second station; and a second station adapted to receive a hollow blank from the first station and comprising a blow mould and blowing means cooperable therewith to form the blank into a blow-moulded glass article; CONFIRMAΗON COPY the blow mould comprising two or more mould parts and being adapted to open or close by relative linear movement of the two or more mould parts. 4. A glass forming apparatus according to any of Claims 1 to 3, in which the hollow glass articles comprise tableware. 5. A glass forming apparatus according to any of the preceding claims, which also comprises a gob feeder. 6. A glass forming apparatus according to any one of the preceding claims, in which the blank mould is of unitary construction and mounted for reciprocal vertical motion. 7. A glass forming apparatus according to any one of the preceding claims, in which the plunger is arranged vertically above the blank mould and mounted for reciprocal vertical motion. 8. A glass forming apparatus according to any one of the preceding claims, which is provided with a transfer means adapted to transfer the hollow blank from a first station to a second station, and in which the transfer means comprises one or more neck means which receive(s) the moil of the hollow glass CONFIRMAΗON COPY blank formed by the action of the plunger on the glass gob. 9. A glass forming apparatus according to Claim 8, in which the transfer means comprises one or more elongate arms which is/are reciprocally rotatable in a horizontal plane above the moulds. 10. A glass forming apparatus according to any one of the preceding claims, in which the blow mould is a paste mould. 11. A glass forming apparatus according to Claim 2 or 3, which comprises a plurality of second stations each adapted to receive a hollow blank from the first station and comprising a blow mould and blowing means cooperable therewith to form the hollow blank into a blow-moulded hollow article. 12. A glass forming apparatus according to any one of the preceding claims, which comprises one first station and two second stations. 13. A glass forming apparatus according to Claim 2 or 3, which comprises a transfer means adapted to transfer the hollow blank from the first station to a second station, and to rotate the hollow blank about its vertical axis whilst it is being transferred from the first station to a second station. 14. A glass forming apparatus according to Claim 1 or 3, which comprises a retractable gob deflector adapted to receive a glass gob from a gob feeder and deflect the glass gob into the blank mould, the gob deflector being retractable from a first gob deflecting position in which it is situated between the blank mould and the plunger to a second position in which the gob deflector does not interfere with the movement of the blank mould or the plunger in the formation of the hollow blank. 15. A glass forming apparatus according to Claim 1 or 2, which comprises a second station adapted to receive a hollow blank from the first station and comprising a blow mould and blowing means cooperable therewith to form the hollow blank into a blow moulded article; the blow mould comprising two or more mould parts and being adapted to open or close by relative linear movement of the two or more mould parts. 16. A glass forming apparatus according to any of the preceding claims, which comprises a gob deflector in the form of an elongate downwardly depending metal channel which is positioned, in gob deflecting operation, such that its lower end is substantially vertically above the open mouth of the blank mould. 17. A glass forming apparatus according to any of the preceding claims, in which neither the blank mould nor the plunger can move in a horizontal plane in normal operation. 18. A glass forming apparatus according to any of the preceding claims, which comprises a blow mould comprising two mould halves and adapted to open and close by relative linear movement of the said mould halves on linear slides. 19. A glass forming apparatus according to any one of the preceding claims substantially as hereinbefore described with reference to and as illustrated in the accompanying Drawings. 20. A glass forming apparatus substantially as hereinbefore described. 21. A method of forming a hollow glass article in which there is used a glass forming apparatus according to any one of the preceding claims. CONFIRMAΗON COPY 22. A method of forming a hollow glass article substantially as hereinbefore described. 23. A hollow glass article formed by a glass forming apparatus according to any of Claims 1 to 20 and/or by a glass forming method according to Claim 21 or 22. CONFIRMAΗON COPY

Inventors: ORWIN DAVID WILLIAM, SADDOO LESLIE WASHINGTON, SMITH ROGER ANDREW, ORWIN, DAVID, WILLIAM, SADDOO, LESLIE, WASHINGTON, SMITH, ROGER, ANDREW
Applicants: DEMA LTD, ORWIN DAVID WILLIAM, SADDOO LESLIE WASHINGTON, SMITH ROGER ANDREW, DEMA LIMITED, ORWIN, DAVID, WILLIAM, SADDOO, LESLIE, WASHINGTON, SMITH, ROGER, ANDREW
Application year: 1995
Main classification: C03B9
IPC codes: C03B7, C03B9