GB2367875A

GB2367875A - Rack and screw mechanism for a glass container forming machine

Info

Publication number: GB2367875A
Application number: GB0119582A
Authority: GB
Inventors: Alan F Fenton; Zdenko Kuz
Original assignee: Emhart Glass SA
Current assignee: Emhart Glass SA
Priority date: 2000-09-28
Filing date: 2001-08-10
Publication date: 2002-04-17
Also published as: FR2814456A1; AU7606001A; CZ20013415A3; DE10138529A1; ITMI20011984A1; ITMI20011984A0; JP2002187725A; GB0119582D0

Abstract

The invention relates to a mechanism, such as an invert mechanism for an I.S. machine, which has a rotatable shaft 4 including a gear 6 secured thereto. The shaft 4 is rotated by a drive assembly which includes an elongate rack member 10 having teeth 11 engaging the gear. The elongate rack member 10 has a hole 42 extending from one end in which is secured a nut 48 which threadedly receives a motor driven screw-threaded rod 38 telescopically located in the hole 42. Rotation of the rod 38 effects displacement of the rack member 10.

Description

2367875 MECHANISM FOR GLASS CONTAINER FORMING MACHINE This invention is

concerned with mechanisms for use in an individual section (I.S.) glass container-forming machine.

In the operation of an I.S. machine, a parison is formed from a gob of molten glass in a blank mold at a blank station, 5 with the neck of the parison in a neck ring. The ring is carried by neck ring arms of an invert mechanism. The blank mould then opens, and the parison, supported by the neck ring is swung by the invert mechanism through 180 degrees to position the parison at a blow station where the parison is 10 positioned in a blow mould. The neck ring is then opened to release the parison into the blow mould and the neck ring arms revert through 180 degrees to carry the neck rings back into position against the blank mould for the..cycle to be repeated and another parison to be formed. conven''tionally an invert 15 mechanism has been operated pneumatically, though hydraulically operated invert mechanisms have also been suggested. There is at the present time a desire to operate mechanisms in a glass machine by electric servo motors, as such motors offer the possibility of more precise control of the operation of an 20 invert mechanism.

The use of servomotors in an invert mechanism has been suggested in IT 1247203. In one of the two constructions described in this specification, the servo motor drives a ball screw arrangement comprising a threaded rod which is positioned

25 below the table of the machine, and a rack extends upwardly from the rod. when the servomotor operates to rotate the rod it is forced upwardly by the nut and causes the rack to move up, thus to rotate a neck ring mechanism to cause the neck rings to move from a revert to an invert position. This arrangement 30 suffers from certain disadvantages, in particular the motor and the ball screw extending for a substantial distance below the table of the machine, which not only may require other mechanisms to be moved to allow it room but also requires an expensive construction to provide the necessary rigidity for the length of mechanism extending below the table. It 5 will be realized that it is necessary that the whole mechanism can be removed upwardly through the table, and that therefore external stabilizing below the table is not practicable.

One of the objects of the present invention is to provide a mechanism suitable for an invert mechanism, which utilizes a servomotor and is compact 10 and robust in construction.

Another object of the present invention is to provide a mechanism suitable for any mechanism in an I.S. machine, such as a takeout, gob distributor, shear mechanism, mold open and close mechanism, etc., which can be driven with a rack.

15 According to the present invention, there is provided a mechanism for an I.S. machine, comprising a rotatable shaft including a gear secured thereto, and a drive assembly for engaging the gear and rotating the shaft including an elongated member having a rack, a slide surface, and a hole extending from one end, a housing for the elongated member having a bearing surface for engaging the slide surface of said elongated member as the elongated member is displaced between advanced and retracted position, internally threaded means associated with said elongated 25 member, a drive rod having a screw threaded portion for threadedly engaging the internally threaded means, the screw threaded portion of the drive rod being located within the hole in the elongated 3 member and having a length sufficient to permit displacement said threaded means and the elongated member secured thereto between the advanced and retracted positions, rotation prevention means for preventing the rotation of the threaded means when the drive rod rotates, and a servo motor coupled to said drive rod for rotating said drive rod.

The invention also provides an I.S. machine provided with one or more mechanisms as defined above.

10 According to one embodiment, there is provided a drive assembly for a mechanism in a glass bottle making machine, which comprises: an elongate member or mechanism-d riving member moveable between a retracted position and an advanced position to drive the mechanism, a drive member such as a drive rod having a screw threaded portion which is generally 15 coextensive with the driving member when the driving member is in the retracted position, a nut on the drive rod which is constrained from rotation with the drive rod and which engages the driving member, and a servo motor positioned coaxially with the drive rod and arranged to rotate the drive rod to cause movement of the nut and hence of the driving member to drive the 20 mechanism.

Preferably, in a drive assembly as just set out, the driving member has an axial bore, hoie or passage in which the drive rod is positioned when the driving member is in the retracted position.

A drive assembly as just set out is particularly convenient when the 25 driving member is or includes a rack member adapted to drive a gear of the mechanism.

Again, preferably, a drive assembly as set out above comprises a housing in which the rack member is mounted for movement, and a support plate secured in the housing slidably engaging the rack member opposite the 30 area of engagement between the rack member and the gear.

4 A drive assembly as set out above comprising a rack me miber is particularly useful as an invert mechanism, but may be utilized in conjunction with the other mechanisms, for example a take out mechanism, a mold open and close mechanism, a shear mechanism or a gob distributor.

5 A drive assembly embodying the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 shows a perspective view of an invert mechanism and part of a neck ring mechanism of an I.S. machine; Figure 2 shows a vertical section of the invert mechanism taken along 10 the line 11-11 of Figure 3; and Figure 3 shows a horizontal section taken along the line III-III of Figure 2.

A drive assembly 8 in the form of an invert mechanism (Fig. 1) is adapted to rotate a shaft 4 of a neck ring mechanism, not all of which is 15 shown, on which are mounted two supporting bosses 3 to which neck ring arms will be secured. A gear ring 6 is fixed to the shaft 4. The assembly 8 comprises a driving member in the form of an elongate rack member 10 (Fig.

2) which has a row of teeth 11 which are in engagement with the gear ring 6 and which is moveable between a retracted position, shown in Fig. 2 and 20 an advanced position, not shown, in which the rack member extends upwards from the assembly having rotated the gear ring 6 counterclockwise, viewing Figures 1 and 2, from a start orientation to an end orientation. A rack housing 12 is formed from a main housing member 14 and a cover member 16 which are secured together by bolts 18. The housing members 25 each includes a side face 22, 24 (Fig. 3) and an inwardly projecting rib 15, 17. The main housing member also has a rear wall 13. Together, these surfaces define an interior volume for receiving the generally rectangular rack member 10. At the top of the rear wall 13 is a cut out 9 into which is secured a support plate or bearing block 19 which will define a slide surface 30 7 for the rear face 21 of the rack member. The bearing block is secured to the main housing with a number of screws 23. The members 14 aind 16 also include outwardly extending flanges 26 and 28 by which the drive assembly may be secured to the top plate of an I.S. machine by bolts 30.

Secured to the housing members 14 and 16 and extending 5 downwardly is a supporting member 32 which comprises a downwardly extending casing portion 33 and a flange 34. An electric servo motor 36 is secured to the flange 34. The motor 36 is coaxial with and connected to a drive member in the form of a drive rod 38 through an overload safety coupling 40. The drive rod 38 has a screw threaded portion 39 which 10 extends generally coextensively with the rack member 10 when the rack member is in its retracted position shown in Figure 2, the rod 38 being located in a hole or bore 42 in the rack member 10. In threaded engagement with the rod 38 is a nut 48 which is secured, by screws not shown, in a recess in the lower end portion of the rack member 10 and which is thus 15 constrained against rotation with the rod 38. The unthreaded portion of the rod passes through a bushing 43, an angular contact bearing assembly 44 and a double seal arrangement 46 into the bore 42. The threaded portion 39 extends from close to the seal arrangement 46 nearly to the upper end of the rack member 10. On rotation of the drive rod 38 the nut 48 is forced to 20 move along the drive rod 38 and thus moves the rack member which is integral therewith from the retracted position shown in Figure 2, upwards to an advanced position in which the rack member extends up through the rack housing 8, rotating the gear ring 6 to move the neck ring mechanism through approximately 180 degrees as it so moves. While in Figure 2 the servo 25 motor is shown at the bottom, the entire mechanism could be inverted, if desired. The screw and nut can be a simple screw or a ball screw if desired.

The drive rod 38 has an axial bore 50 in the upper end portion in which is positioned a plug 52 having an axial passage 54. The plug 52 secures a washer 56, which, by engagement with the lower end of the bore 30 42, limits the upward movement of the rack member 10. The retracted, 6 lower position of the rack member is determined by the nut hitting the' top of the servo motor assembly. The upper end of the bore 42 is closed by a plug 58.

The drive assembly 8 is provided with a lubrication system. Oil is 5 provided to the bearing assembly 44 through a passageway 62 which extends through the main housing member 14 and the supporting member 32 to the assembly 44. Oil is provided to nut 48 through a passageway 64 which extends through the main housing member 14 and the supporting member 32 to the seal arrangement 46. The oil then passes through a 10 groove 66 in the arrangement 46 and holes 68 in the drive rod 38 into the axial bore 50 of the drive rod 38. The bore 50 is filled with oil, which flows out through the passage 54 in the plug 52, down through the bore 42 of the rack member 10 to lubricate the nut 48. The contact area between the slide surface 7 of the bearing block 19 and the rack member 10 is lubricated 15 through a passageway 70 extending through the housing member 14 and the bearing block 19.

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Claims

1 A mechanism for an I.S. machine, comprising a rotatable shaft including a gear secured thereto, and a drive assembly for engaging the gear and rotating the shaft including an elongated member having a rack, a slide surface, and a hole extending from one end, a housing for the elongated member having a bearing surface for engaging the slide surface of said elongated member as the elongated member is displaced between advanced and retracted position, internally threaded means associated with said elongated 10 member, a drive rod having a screw threaded portion for threadedly engaging the internally threaded means, the screw threaded portion of the drive rod being located within the hole in the elongated member and having a length sufficient to permit displacement said threaded means and the elongated member secured thereto between the advanced and retracted positions, rotation prevention means for preventing the rotation of the threaded means when the drive rod rotates, and a servo motor coupled to said drive rod for rotating said 20 drive rod.

2. A mechanism for an I.S. machine according to claim 1, wherein said elongated member has the rack located on one side thereof and said slide surface located on the opposite side of the elongated member to the rack, 25 and said internally threaded means comprises an internally threaded nut secured within the hole of said elongated member.

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3. A mechanism for an I.S. machine according to claim 1 or 2, wherein the mechanism is an invert mechanism.

4. A mechanism for an I.S. machine according to claim 1, 2 or 3, wherein the threaded portion of said drive rod is approximately the same length as said rack.

5. A mechanism for an I.S. machine according to any preceding claim, wherein said elongated member is rectangular in cross section and said housing includes parallel sides for preventing the rotation of said elongated 10 member, wherein the parallel sides and the square cross section comprise said rotation prevention means.

6. A mechanism for an I.S. machine according to claim 2, or claim 3, 4 or 5 in combination with claim 2, wherein said nut is secured at the one end 15 of said hole.

7. A mechanism for an I.S. machine substantially as hereinbefore described with reference to the accompanying drawings.

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8. An I.S. machine provided with one or more mechanisms according to any preceding claim.