WO2025083567A1

WO2025083567A1 - Apparatus for machining rings for gaskets

Info

Publication number: WO2025083567A1
Application number: PCT/IB2024/060129
Authority: WO
Inventors: Gian Piero Barozzi; Lorenzo Facchinetti
Original assignee: GSKET Srl
Current assignee: GSKET Srl
Priority date: 2023-10-20
Filing date: 2024-10-16
Publication date: 2025-04-24
Anticipated expiration: 2026-04-20
Also published as: IT202300021918A1

Abstract

An apparatus for machining rings for spiral wound gaskets comprises a flat support plate (10), rotationally driven vertical-axis rotating rollers for rotationally driving a ring (1,2) being machined along a horizontal circle arc path defined between the rotating rollers and pressing means (60) which press the ring being machined against the rotating rollers. A tool-holder turret (20) carries a first tool group (21a, 21b) for machining an inner side of the ring (1) and a second tool group (22) for machining an outer side of the ring (2), the groups being arranged on opposite sides of the turret. The turret moves horizontally between a position radially on the inside of arc path and and a position radially on the outside of the arc path, allowing the machining of both inner and outer sides of a ring. The turret is also movable in the vertical direction (Z-Z).

Description

APPARATUS FOR MACHINING RINGS FOR GASKETS

DESCRIPTION

The present invention relates to an apparatus for machining rings for gaskets, in particular spiral wound gaskets, which allows the machining of both inner rings and outer rings.

It is known in the technical sector of spiral wound gaskets to use metal rings which have a substantially rectangular cross-section for supporting the sealing material. Depending on the type and the intended use of the gasket, these rings may have dimensions which vary substantially both as regards the inner diameter, ranging between 160 mm and 4000 mm, and as regards the thickness, which may vary from 2 mm to 5 mm.

These rings are conventionally referred to as:

- inner ring, since they are positioned on the inside of the gasket and have an outer machined surface which is generally finished with an external V- shaped cusp (Figs. 1a, 1b) or

- outer ring, since they are positioned on the outside of the gasket and have an inner surface with an internal V-shaped circumferential recess (Figs. 2a, 2b).

Also known are specially designed machines for machining these rings which have, however, a number of limitations due to the difficulty of adapting to the variation in the dimensions of the ring to be machined; in particular, these known machines require special setting operations when there is a variation in diameter of the rings, and replacement of the tools when changing over from a machining operation for an inner ring to a machining operation for an outer ring.

In addition, their pressing system which acts on the ring to be machined, in order to cooperate with wheels for rotationally driving the ring and to perform the movement of the ring, tend to deform and buckle the ring when very thin forms must be obtained, in particular for the cusps of the inner rings.

The movement transmission system which has gearwheels or toothed belts is noisy and the various parts of the transmission must be replaced when they become worn.

The technical problem which is posed, therefore, is that of providing an apparatus for machining rings for spiral wound gaskets which solves or at least partially overcomes one or more of the said problems of the prior art.

In connection with this problem it is also required that the apparatus should be easy and inexpensive to assemble.

Advantageously, it is envisaged providing a machine comprising said apparatus.

These results are obtained according to the present invention by an apparatus for machining rings for spiral wound gaskets according to the characteristic features of Claim 1.

Further details may be obtained from the following description of a nonlimiting example of embodiment of the subject of the present invention provided with reference to the attached drawings in which:

Figure 1: shows a top plan view of the apparatus according to the invention for machining an inner ring;

Figure 1a: shows a top plan view of an inner ring;

Figure 1b: shows a view of the turret during machining of an inner ring;

Figure 1c: shows a cross-section through the inner ring of Fig. 1a which has been machined;

Figure 2: shows a top plan view of the apparatus according to the invention for machining an outer ring;

Figure 2a: shows a top plan view of an outer ring;

Figure 2b: shows a view of the turret during machining of an outer ring;

Figure 2c: shows a cross-section through the inner ring of Fig. 2a which has been machined;

Figure 3: shows a perspective view of the tool-holder turret for machining the rings;

Figure 4: shows a side view of the means for moving the turret according to Fig. 3 for changing over from machining an inner ring to machining an outer ring;

Figure 5: shows a side view of the means for moving the means for applying pressure against the ring being machined;

Figure 6: shows a perspective view of the protection means designed to prevent the interference of the machining swarf with the moving parts of the apparatus; and

Figure 7: shows a perspective view of a machine for machining rings comprising an apparatus according to the invention. As shown and assuming for easier description two non-limiting directions, i.e. a longitudinal radial direction X-X and a vertical direction Z-Z as well as a part conventionally defined as front part “A” and a part conventionally defined as rear part “P”, opposite to the front part, in the longitudinal direction X-X, an apparatus according to the invention for machining rings comprises a flat support plate 10 (Figs. 1,2,5) which defines an upper surface 10a and a lower surface 10b.

A tool-holder turret 20 (Fig. 3) which carries tools for machining the ring 2 is arranged on the upper surface. The turret 20 is movable in both directions, i.e. the longitudinal direction X-X and vertical direction Z-Z, by means of associated movement means 30 (Fig. 4) for moving the turret in the longitudinal direction and movement means 40 for moving the turret in the vertical direction (Fig.3).

A pair of vertical-axis rotating rollers (Figs.1,2, 5) project from the upper surface 10a and are designed to rotationally drive the ring 1,2 being machined; preferably, the rollers 50 have a knurling for increasing the contact friction with the ring 1 ,2.

Each roller 50 (Fig. 5) may be rotationally driven by means of a shaft M1 of a motor M to which it is connected by means of a respective constant-velocity joint M2.

The rollers 50 cooperate with means 60 (Figs. 1,2) for pressing the ring 1 ,2 being machined against the rotational drive rollers 50, so that a circle arc path is defined between the driving rollers 50 and the pressing means 60, wherein, during use, the ring 2 being machined is positioned at a tangent to the rollers 50 and rotates under the action of the rollers 50 and the pressing means 60.

In greater detail, the tool-holder turret 20 (Fig. 3) is integral in translation with a support 25 which can be translated in both senses of the longitudinal direction X-X and has a vertical body, for example with a substantially frustoconical form, projecting vertically from the upper surface of the plate 10.

In diametrically opposite positions along the longitudinal axis X-X of translation, a first work-tool group for machining an inner ring and a second work-tool group for machining an outer ring are mounted on the side surface

The first tool group comprise preferably a first pair of cutters 21 a, 21b which are adjacent to each other in the vertical direction for cutting the outer circumferential surface of an inner ring 1 in the form of an external V-shaped cusp V1 (Figs. 1b, 1c); the two cutters are in particular arranged adjacent so as to leave an interstice 21c for allowing the entry in the longitudinal direction of the outer circumferential edge of the inner ring 1 (Fig. 1a).

The size of the cusp-shaped profile may vary depending on the working stroke of the turret along the longitudinal axis X-X in accordance with the commands of the movement means, in particular of the numerical control axle.

The second tool group preferably comprises a cutter 22, the edge 22a of which is designed to make an incision in the inner surface 2a of an outer ring 2 so as to create a V-shaped recess V2.

The turret body 20 is preferably integral at the bottom with a graduated ring nut 41 (Fig. 3), which rotates with respect to the support 25 and the rotational actuation of which causes raising/lowering of the turret 20 and therefore of the tool groups with cutters to a machining height defined depending on the thickness of the ring being machined. Once the vertical working position is reached, the turret is locked in position by means of a bolt 23 connected to the support 25.

The support 25 has a vertical flange 25a which, by means of a pin 31b, is in turn connected to the means 30 for translation of the turret in the longitudinal direction X-X. The translation means 30 comprise a linear axle 31 which is fixed to the lower surface 10b of the plate 10. The vertical flange 25a therefore passes through the support plate 10 along a longitudinal radial slot inside which it is displaceable so as to translatably connect the turret 20 arranged above the plate 10 with the means 30 for translatably actuating the turret, arranged underneath the support plate 10.

Said means 60 for pressing the ring being machined against the rotational drive rollers comprise (Figs. 1 ,2,5) pairs of bearings 61 , which are preferably supported by a rocker arm 62 pivotably mounted on a flange 63 which is translatably moved by a cylinder 64, the rod 64a of which is connected to the flange 63 which carries the rocker arm 62; the translation of each pair of bearings 61 takes place in both senses of a respective radial direction in relation to the arc path, different from the longitudinal direction X-X and passing through the respective roller 50.

Overall, the bearings 61 with the rocker arm 62 and translating flange form a preferred example of embodiment of self-aligning bearings.

Preferably, the radial axis of translation of each pair of bearings is arranged inclined with respect to the longitudinal axis X-X and the radial axes converge in a central point substantially corresponding to the centre of the arc-shaped path. An angle of inclination of the radial axes with respect to the longitudinal axis, in the plane of the support plate 10, ranges preferably between 20° and 25° and in particular is equal to 22°.

In preferred embodiments, the longitudinal radial axis of translation of the turret 20 is arranged along the bisector of an angle included between the radial axes of translation of the pressing means 60.

All the movements are controlled and commanded by means of control means such as a PLC 500 or the like provided with data entry and display means, conventional per se and not described in detail, as well as a management program designed to control automatically the movements of the work cycle of the apparatus.

With this configuration the operating principle of the apparatus is as follows: INNER RING (Figs.1,1 a, 1b, 1c)

For machining of an inner ring, the data relating to diameter, thickness and speed of rotation of the ring 1 , position of the turret and therefore the cutting tools in the longitudinal direction, and working depth, are entered into the PLC; the turret 20 is displaced towards the rear part P so as to position it on the outside of the circle arc path and therefore of the ring 1 which is introduced between the rotational driving rollers 50 and the pressure bearings 61 pushed against the ring by the respective actuating means 60; the ring nut 41 is rotated (Fig. 1b) so as to adjust the vertical position of the pair of cutters 21 a, 21b directed towards the ring 1 , for correct contact therewith; the machining controlled by the PLC is started and, on the basis of the data entered beforehand, the formation of the cusp V1 on the outer side surface of the ring 1 is performed; when machining has finished, the turret is moved back towards the rear part P, translating it along the longitudinal direction.

OUTER RING (Fiqs.2,2a,2b,2c) For machining of an outer ring 2, the data relating to diameter, thickness and speed of rotation of the ring 2, position of the turret, and therefore of the cutting tools in the longitudinal direction, and working depth are entered into the PLC; the turret 20 is displaced towards the front part A so as to position it on the inside of the circle arc path and therefore of the ring 2 which is introduced between the rotational driving rollers 50 and the pressure bearings 61 pushed against the ring by the respective actuating means; the height of the turret in the vertical direction Z-Z is adjusted (Fig. 2b) for correct contact with the ring by the tool 22; the machining controlled by the PLC is started so as to form the recess V2 along the inner side surface of the ring 2.

According to a preferred embodiment of the apparatus, said embodiment comprises (Figs. 4-6) protection means 70 which prevent the swarf produced by machining from passing from the top part to the bottom part of the support plate 10, preventing the swarf from interfering with the various moving parts of the apparatus.

Said means comprise preferably laminar plates, for example made of tempered steel, arranged in the upper surface of the support plate 10, three of these 71 a, 71b, 71c forming a container for a fourth laminar plate 72 slidable inside it.

In greater detail (Fig. 4), a first container 70 is arranged in the support plate 10 inside a longitudinal radial slot along which there moves an element 25a for connecting together the turret 20, arranged above the plate 10, and the linear axle 30 for translation of the turret 20 (arranged below the plate 10); the fourth laminar plate 72 has a hole for allowing the vertical passage of said connection element 25a and is slidable inside the container so as to keep said longitudinal radial slot closed upon variation of the position of the turret 20 along the longitudinal axis X-X.

Similar protection means 70 may be provided for each pressing group 60, comprising (Fig. 6) three laminar plates 71a, 71b, 71c which form a respective container arranged in the upper surface of the support plate 10 inside a radial slot along which the rod 63 moves (Fig. 5) acting on the rocker arm 62 so as to displace the bearings of the pair 61 from/towards the respective drive roller; a fourth laminar plate 72 has a vertical through-hole for insertion of the rod 63 and is slidable inside the container so as to keep said radial slot closed upon a variation in the position of the pair of bearings along the radial direction.

This solution isolates perfectly the top part from the bottom part, preventing the passage of swarf and replaces the standard bellows-type isolating means which with time tend to develop cuts due to wear, allowing also the transmission of the movement from the bottom part to the top part within an extremely small space, without hindering the evacuation of the swarf.

The choice of tempered steel as a material reduces the wear generated by the swarf and increases the resistance to the high temperature of the swarf itself.

It is therefore clear how the apparatus and the machine according to the invention offer numerous advantages compared to the prior art: the tool-holder turret may operate both on the outside of the ring, as in the case of an inner ring, and on the inside, as in the case of an outer ring, allowing the machining of inner and outer rings with the same thickness without the need for any preparation or replacement, but only using the two control programs already provided and displacing the turret in the longitudinal direction.

In addition to this, the heightwise adjustment of the turret allows the machining of different thicknesses upon variation in the thickness of the ring being machined and is valid both for inner rings and for outer rings.

The double drive system with knurled rollers for transmission of the movement to the ring allows the machining of rings with thicknesses varying from 2 mm to 5 mm, without the need for replacement of the rollers for rotationally driving the ring.

Owing to the self-aligning multiple bearing pressing system, the specific pressure exerted by the bearings on the part being machined may be halved, preventing the buckling of the said part during machining, even though the machining surface on which the rollers exert pressure is reduced to less than one sixth of the initial surface owing to the removal of material.

The solution of self-aligning multiple bearings allows distribution of the pressure, with adaptation to all diameters; it is therefore not necessary to vary the inclination of the pressing groups as instead is required in the case of a single roller in order to keep it always radial with respect to the centre of the ring. The apparatus also reduces the vibrations during machining, being very silent compared to the known apparatus which use belts or gearwheels.

The protection means for preventing the swarf from passing to the bottom part of the support plate, by means of tempered laminar plates, favours smaller overall dimensions and eliminates the wear and replacement over time of parts.

In preferred embodiments (Fig. 7) an apparatus 100 for machining rings according to the invention comprises preferably a compartment 110 for collecting the swarf which is removed from the machining zone by means of compressed air jets supplied via special nozzles 120, as well as a partition 121 for housing the means 500 for controlling the apparatus.

A lid 130 closes the apparatus at the top, ensuring safe conditions for the operator.

Although described in connection with a number of embodiments and a number of preferred examples of implementation of the invention, it is understood that the scope of protection of the present patent is determined solely by the claims below.

Claims

1. Apparatus for machining rings for spiral wound gaskets, comprising: a flat support plate (10) which defines an upper surface (10a) and a lower surface (10b); vertical-axis rotating drive rollers (50) for rotationally driving a ring (1;2) being machined and actuating means (M,M1) for rotationally actuating the drive rollers (50); pressing means (60) for pressing the ring being machined against the rotating rollers; wherein a circle arc path for the ring (1 ;2) being machined is defined between the drive rollers (50) and the pressing means (60); a tool-holder turret (20) which projects in the vertical direction from the upper surface of the support plate (10) and carries a first tool group (21 a, 21b) for machining an inner ring (1) and a second tool group (22) for machining an outer ring (2), the first tool group and the second tool group being arranged on opposite sides of the turret in a longitudinal direction (X- X); first turret movement means (30) for moving the turret (20) in the longitudinal direction (X-X) between a position radially on the inside of the arc path and therefore of the ring (1) being machined and a position radially on the outside of the arc path and therefore of the ring (1 ,2) being machined; second turret movement means (40) for moving the turret (20) in the vertical direction (Z-Z).

2. Apparatus according to Claim 1, characterized in that the toolholder turret (20) is integral in translation with a support (25) which can be translated in both senses of the longitudinal direction (X-X), said first turret movement means comprising a linear axle (31) arranged underneath the lower surface (10b) of the support plate (10) and acting on said support (25).

3. Apparatus according to Claim 1 or 2, characterized in that the first tool group comprises a pair of cutters (21a, 21b) adjacent to each other in the vertical direction for cutting the outer side surface of an inner ring (1) in the form of an external V-shaped cusp (V1 ); and/or in that the second tool group comprises a cutter (22) configured to make an incision in the inner surface (2a) of an outer ring (2) so as to create a V-shaped recess (V2).

4. Apparatus according to one of the preceding claims, wherein the turret (20) has a vertical turret body which carries said first and second tool groups and at the bottom is integrally joined with an adjustment ring nut (41) rotating about a vertical axis, wherein rotational operation in one direction or the other of the ring nut causes raising or lowering of the turret body (20) and therefore of the tool groups with respect to the support plate, for adjustment of the working height depending on the thickness of the ring (1 ;2) being machined.

5. Apparatus according to one of the preceding claims, characterized in that said pressing means (60) for pressing the ring being machined against the drive rollers for rotationally driving said ring comprise at least two pairs of bearings (61) arranged to push against the ring being machined.

6. Apparatus according to the preceding claim, wherein said pairs of bearings (61) are self-aligning.

7. Apparatus according to Claim 5 or 6, wherein each pair of bearings is displaceable in both senses of a respective radial direction different from the longitudinal direction (X-X) and passing through a respective rotational driving roller (50).

8. Apparatus according to the preceding claim, wherein each pair of bearings is mounted on a respective rocker arm (62) pivotably mounted on a flange (63) displaceable in both senses of the respective radial direction, preferably actuated by means of the rod (64a) of a cylinder (64) fixed underneath the lower surface of the plate (10).

9. Apparatus according to one of the preceding claims, characterized in that it comprises protection means (70) designed to prevent swarf, produced by machining, from passing from the upper surface to the lower surface of the support plate (10).

10. Apparatus according to the preceding claim, characterized in that said protection means comprise four laminar plates, three of which (71a, 71b, 71c) form a container arranged in the support plate (10) in a longitudinal radial slot along which an element connecting together the turret (20) and the first turret movement means moves, the fourth laminar plate (72) being slidable inside the container so as to keep said longitudinal radial slot closed upon a variation in the position of the turret (20) along the longitudinal direction.

11. Apparatus according to Claim 9 or 10 when dependent on Claim 7 or 8, wherein said protection means comprise, for each pair of bearings, four laminar plates, three of which (71a, 71b, 71c) form a respective container arranged in the support plate (10) in a radial slot along which the bearings of the pair move away from/towards the respective drive roller, a fourth laminar plate (72) being slidable inside the container so as to keep said radial slot closed upon a variation in the position of the pair of bearings along the radial direction.

12. Apparatus according to one of the preceding claims, comprising control means (500) for automated operation of the moving parts and the machining cycle.

13. Apparatus according to Claim 12, characterized in that said control means (500) comprise means for entering and displaying data relating to the ring being machined.

14. Apparatus according to Claim 13, characterized in that said data comprises one or more of the following: diameter, thickness and speed of rotation of the ring (1,2), position of the turret and therefore of the cutting tools in the longitudinal direction, machining depth.

15. Apparatus according to one of the preceding claims, wherein the actuating means (M,M1) for rotationally actuating the rollers (50) comprise a shaft (M1) of a motor (M) connected via a constant velocity joint (M2) to each drive roller (50).

16. Apparatus according to one of the preceding claims when dependent on Claim 6, wherein the longitudinal radial axis of translation (X-X) of the turret (20) is arranged along the bisector of an angle included between the radial axes of translation of the pairs of bearings (61) of the pressing means (60).