TRANSPORTABLE COMPACT CORRECTION DEVICE IN PARTICULAR FOR POLISHING CALENDERING CYLINDERS

The present invention relates to the field of corrective grinding devices intended to machine, by abrasion, the surface of parts of revolution.

The present invention relates more particularly to corrective grinding devices intended for the polishing, and in particular the superfinishing, of cylinders, and more particularly of cylinders belonging to calendering installations, such as calendering installations intended to manufacture webs based on raw rubber, i.e. based on unvulcanized rubber.

It is known practice in many fields, such as rolling, calendering, or even printing, to use machines comprising at least two counter-rotating cylinders which cooperate with each other to drive one or more materials and to press it/them through the nip between them.

The passage of the material or materials between the cylinders naturally, over time, causes the surface of said cylinders to become impaired through wear. This wear can be particularly rapid when thermal and/or chemical stresses are added to the mechanical stresses.

As a result, it is necessary to periodically rectify the cylinders, by polishing their surface by means of an abrasive, in order to restore to said cylinders a surface profile and a surface finish which correspond to those required.

As such, a first known solution consists in dismantling the cylinder to be corrected from the frame of the installation to which the cylinder belongs, then in placing said cylinder in a corrective grinding machine where it is polished, and then, after corrective grinding, in re-integrating the corrected cylinder in its original installation.

Such a solution, however, requires the implementation on the one hand of heavy handling operations, which are particularly long and potentially risky both for the cylinder and for the operators who take part in these operations, and on the other hand of numerous adjustment operations. during the refitting of the corrected cylinder in its original installation, including in particular an adjustment of the centre-distance between cylinders.

As a result, the time required to correct the cylinder, which for the installation to which the cylinder belongs is downtime and therefore unproductive, is therefore particularly long.

To limit these drawbacks, another solution has been proposed, which consists in using transportable corrective grinding machines, capable of working on a cylinder which remains in place in its installation. Such machines generally comprise a rail-type base, which is placed parallel to the axis of rotation of the cylinder to be ground, and along which there move one or more machining heads bearing abrasive elements, for example abrasive belts.

However, such transportable corrective grinding machines remain relatively heavy and bulky, so that transporting them to the installation concerned is complex and costly. In addition, the machining heads fitted to such machines are particularly bulky, since they must carry, on the one hand, the structure for pressing the abrasive belt against the cylinder and, on the other hand, a powerful motor intended to drive said abrasive belt with a motion able to produce a corrective grinding effect, said motor being located offset from the abrasive belt, for example on the side of the abrasive belt in the direction of the axial length of the cylinder, and therefore in the direction of the length of the base. Therefore, it is necessary either, in a first case, to provide a base that is very long, and more particularly of a length greater than the length of the cylinder to be ground, so as to ensure that the axial travel of the machining head is sufficient to cover the entire length of the surface to be ground, or, in a second case, to multiply the number of machining heads and to allocate to each a section of the surface to be ground.

However, in the first case, the longer the base, the more it is subject to bending, which can degrade the quality and precision of the surface obtained. In addition, a base longer than the cylinder generally cannot be inserted between the side uprights of the frame, due to lack of space, and this complicates the attachment of the base to the frame and increases the sensitivity of the corrective grinding machine to deformations under stress, in particular in bending.

In the second case, when several machining heads are used to grind the cylinder in successive sections, it frequently happens that, at the transition between two neighbouring sections of a surface to be ground, which are processed by two distinct machining heads, the formation of a ridge-type surface defect is observed, which then requires further specific corrective re-working.

The objects assigned to the invention therefore aim to remedy the aforementioned drawbacks and to propose a light and compact corrective grinding device which makes it possible to machine simply and precisely the surface to be ground of a part of revolution such as a cylinder and which makes it possible to return said part of revolution into service in a very short timeframe.

The objects assigned to the invention are achieved by means of a corrective grinding device intended to machine, by abrasion, a surface called the “surface to be ground” of a part of revolution which has a central axis called the “main central axis” and which is mounted with the ability to rotate on a frame about said main central axis, said device comprising a base which is provided with coupling members making it possible to fix said base on the frame, said device also comprising a machining head which comprises an abrasive belt which is guided along a belt path defined by a plurality of wheels carried by said machining head, these including an applicator wheel intended to press the abrasive belt against the surface to be ground in a first direction called the “penetration direction” which is transverse, and preferably perpendicular, to the main central axis, said machining head also comprising a belt-driving motor of which the stator is fixed to said machining head and which is arranged to drive the abrasive belt in motion along the belt path, the device further comprising a head movement system which makes it possible to move the machining head on the base in a second direction called the “feed direction” which is transverse, and preferably perpendicular, to the penetration direction, so that said machining head can, along the main central axis, cover a so-called “useful feed stroke”, the device being characterized in that, in orthogonal projection in a plane called the “base plane” defined by the feed direction and the penetration direction, the projected surface of the abrasive belt which is in the belt path overlaps the projected surface of the stator of the belt-driving motor.

Advantageously, the arrangement proposed by the invention is such that the belt-driving motor, and more particularly the stator of said motor, which constitutes the bulkiest part of said motor, occupies, along the main central axis of the part of revolution, a region of the space that overlaps the region occupied by the abrasive belt. Thus, the abrasive belt and the belt-driving motor can share the same axial space along the main central axis, with a belt-driving motor, and more particularly the stator of said belt-driving motor, which fits at least partly, or even entirely, in the axial range which is occupied by the width of the abrasive belt.

Thus, at least part, if not all, of the axial width of the stator of the drive motor falls within the axial width of the abrasive belt, which corresponds to the axial extent of the functional zone in which the abrasive belt comes into contact with the surface to be ground and machines said surface to be ground.

In this way, it is possible to have a relatively narrow machining head, within which the belt-driving motor protrudes little, if at all, in the feed direction, with respect to the width of the abrasive belt.

This compactness of the machining head in the dimension which corresponds to the feed direction, which feed direction is in practice substantially or even exactly parallel to the direction of the main central axis, advantageously allows the machining head to cover a large useful feed stroke in the feed direction without the motor coming into abutment against the frame which carries the part of revolution that is being subjected to the corrective grinding operation.

More particularly, the machining head can thus travel, along the main central axis, the entire length of the surface to be ground, without the belt-driving motor colliding with the frame, so that said belt-driving motor does not in any way hinder or block the feed movement of the machining head. The invention therefore makes it possible to maximize the useful feed stroke of the machining head, for a given frame width.

In addition, the compactness of the machining head gives said machining head, and therefore more generally the corrective grinding device, a relative lightness of weight, which in particular favours the transportability of said corrective grinding device, in particular the containerized transportation of said corrective grinding device, and also the installation of said corrective grinding device on the frame.

This lightness of weight is advantageously combined with the presence of coupling members which are designed to ensure temporary and reversible fixing of the base of the corrective grinding device on the frame carrying the part of revolution to be ground, to give said corrective grinding device a removable and easily transportable nature, which allows mobile use of the corrective grinding device, in that said corrective grinding device can first of all be attached and fixed temporarily to the frame in order to machine the part of revolution without it being necessary to extract said part of revolution from the frame, then disassembled and transported to another frame or another location of the same frame in order to machine another part of revolution in a similar manner.

The downtime of the frame, and therefore of the corresponding installation, is therefore particularly short.

Further subjects, features and advantages of the invention will become apparent in more detail from reading the following description and with the aid of the appended drawings, which are provided purely by way of illustration and without limitation and in which:

FIG. 1 illustrates, in an overall perspective view, an installation of the calendering installation type which comprises a frame bearing four rotary cylinders, and a corrective grinding device according to the invention which is fixed to the frame facing a cylinder to be ground.

FIG. 2 is a perspective view of the corrective grinding device used in FIG. 1.

FIG. 3 illustrates, in a perspective view, the detail of the corrective grinding device of FIG. 2, in which the machining head has been stripped of its casing to reveal the various components.

FIG. 4 illustrates, in a perspective view from an opposite angle of view, the corrective grinding device of FIG. 3.

FIG. 5 is a top view, in projection in the base plane formed by the penetration direction and the feed direction, of the corrective grinding device of FIGS. 2 to 4.

FIG. 6 is a rear view, in projection in a plane normal to the penetration direction, and here normal to the axis of the belt-driving motor, of the corrective grinding device of FIGS. 2 to 5.

FIG. 7 is a side view of the corrective grinding device of FIGS. 2 to 6, in a plane normal to the feed direction, which plane here is also normal to the main central axis of the cylinder to be ground.

FIGS. 8A and 8B illustrate, in perspective overall views, the installation of FIG. 1 with respectively, in FIG. 8A, the machining head occupying a first end position on the base, in the feed direction and therefore along the main central axis of the cylinder to be ground, which first end position here corresponds to the left limit forming the starting point of the useful feed stroke, and, in FIG. 8B, the same machining head having reached a second end position on the base, opposite the first end position in the feed direction and therefore along the main central axis of the cylinder to be ground, which second end position here corresponds to the right limit forming the end point of the useful feed stroke.

The present invention relates to a corrective grinding device 1 which is intended to machine, by abrasion, a surface 2A, called “surface to be ground” 2A, of a part of revolution 2.

Said part of revolution 2 has a central axis X2, called “main central axis” X2, and is mounted with the ability to rotate on a frame 3 about said main central axis X2.

The surface to be ground 2A therefore corresponds to the visible, radially outer, surface of the part 2, which surface has a shape of revolution generated by rotation of the profile of the part 2 about the main central axis X2.

The frame 3 is that of an installation 4, for example a calendering installation 4, which bears one or more parts of revolution 2.

Preferably, the part of revolution 2 is a cylinder, more preferably a calendering cylinder. Said cylinder is preferably metallic, and preferably solid, so as to form a massive part of revolution. For convenience of description, it is possible in what follows to liken the part of revolution 2 to a cylinder.

The installation 4 can preferably comprise several parts of revolution 2, 102, 202, 302, here several cylinders 2, 102, 202, 302, mounted on the same frame 3, and for example form a calendering installation comprising four cylinders 2, 102, 202, 302 mounted with the ability to rotate on axes which are parallel to each other, i.e. carried by direction vectors which are collinear with each other, as shown in FIGS. 1, 8A and 8B.

Said cylinders 2, 102, 202, 302 are preferably arranged to work in pairs, and to be driven, within a pair, with counter-rotating movements, so that each pair delimits a nip through which the material or materials to be calendered will pass.

Said nip of course depends on several parameters, which include the centre-distance between the cylinders concerned, the profile of said cylinders, which cylinder profile can be straight, convex (curved outwards), or concave (hollowed), and if applicable the curvature of the axis of the cylinder, if, by construction, in particular by a specific orientation of the bearings, the central axis of said cylinder is forced to follow a slightly curved, i.e. non-rectilinear, shape in order to define a particular nip.

All or some of these various parameters, and in particular the centre-distance, and also, where applicable, the curvature of the axis of the cylinder, may preferably be adjusted by appropriate adjustment means.

Furthermore, the corrective grinding device 1 will preferably be designed to give the surface to be ground 2A a particularly smooth surface finish, of which the arithmetic roughness Ra will typically be less than or equal to 0.4 μm, and more preferably less than or equal to 0.2 μm, or even less than or equal to 0.1 μm to correspond to “superfinishing”. It will be noted that, when the installation 4 is intended for the calendering of one or more rubber-based materials, it is important to have an arithmetic roughness Ra less than or equal to 0.4 μm to avoid difficulties linked to the natural stickiness (tack) of the material.

As is clearly visible in particular in FIGS. 1, 2 and 3, the corrective grinding device 1 comprises a base 5 which is provided with coupling members 6 making it possible to fix said base 5 on the frame 3.

The base 5 is advantageously a rigid structure, which forms a non-deformable support so that, once the base 5 is fixed to the frame 3, said base 5 and said frame 3 as a whole form the same frame of reference, which makes it possible to control the action of the corrective grinding device 1 with respect to the main central axis X2 and therefore benefit from high precision when machining the surface 2A to be ground.

The coupling members 6 can preferably comprise two feet 7, 8, which are each preferably located at one of the axial ends 5A, 5B of the base 5 considered relative to the main central axis X2.

Preferably, as can be seen in FIG. 1, each foot 7, 8 can come into engagement against a corresponding side upright 3A, 3B of the frame 3, which side upright 3A, 3B also carries the bearing, of the ball-bearing or roller-bearing type, which supports the cylinder 2 concerned and guides said cylinder in rotation about its main central axis X2.

Furthermore, the coupling members 6, 7, 8 are preferably provided with reversible fixing means, such as screws, so that the corrective grinding device 1 can be successively:

- i) attached and fixed on the frame 3, so as to carry out a corrective grinding of a first part of revolution 2, here a first cylinder 2, mounted on said frame,
- ii) then detached from the frame 3 after corrective grinding of said first part of revolution 2, and
- iii) transported then fixed either to another location of the same frame 3, which location is associated with a second part of revolution 102, 202, 302 or to a different frame 3 belonging to another installation 4 distinct and remote from the first installation 4, said different frame 3 bearing a second part of revolution 102, 202, 302, the purpose of this being, in each instance, so as to correctively grind said second part of revolution 102.

Advantageously, the device 1 is thus a mobile device, transportable from one installation 4 to another, or from one location to another within the same installation 4 comprising several parts of revolution 2, 102, 202, 302 to be ground, which makes it possible to temporarily fix the device 1 to the frame 3 and to proceed in situ with the operation of correctively grinding the surface to be ground 2A without it being necessary to dismantle and extract the part of revolution 2, 102, 202, 302 to be ground from its functional location within the frame 3.

The overall time required for corrective grinding and then for returning the part of revolution 2, 102, 202, 302 into service is therefore significantly reduced. In addition, since no operation of handling the part of revolution is required, either before or after the corrective grinding operation, any risk of accidentally damaging the newly-ground surface during a handling operation is advantageously eliminated.

Advantageously, once the part of revolution 2 has been ground, the device 1 is simply removed from the frame 3 to let the installation 4 resume operation.

In the installation 4 represented in FIG. 1, it will thus be possible for the corrective grinding device 1, and more particularly the base 5, to be transferred several times so as to fix said device 1 to the frame 3 successively facing the first cylinder 2, so as to grind said first cylinder 2, then facing the second cylinder 102 so as to grind said second cylinder 102, then facing the third cylinder 202, so as to grind the third cylinder 202, and finally facing the fourth cylinder 302, so as to grind said fourth cylinder 302.

It will be noted that the order in which the cylinders of the same installation 4 are ground may in particular depend on the layout configuration of the cylinders, on the shape of the profile of said cylinders, or on the servo-control used for rotating the cylinders. Thus, within the installation 4 of FIG. 1, it is possible, for example, to consider the third cylinder 202 as the main cylinder, and therefore start the corrective grinding by grinding said third cylinder 202, then continue by grinding the second cylinder 102 then adjusting said second cylinder 102—in particular adjusting its centre-distance—relative to the third cylinder 202, and then proceed to the corrective grinding of the first cylinder 2 and the adjustment of said first cylinder 2 relative to the second cylinder 102, then finally proceed to the corrective grinding of the fourth cylinder 302 and the adjustment of the latter relative to the third cylinder 202. This being so, it is perfectly possible to choose another cylinder with which to start the corrective grinding and/or another order in which to successively grind the cylinders 2, 102, 202, 302 mentioned above.

As can be seen in the figures, the device 1 comprises a machining head 10.

Said machining head 10 is mounted with the ability to move on the base 5, as will be detailed below, and makes it possible to press an abrasive element against the surface to be ground 2A, while the part of revolution 2 is rotated about its main central axis X2, so as to be able to machine and polish said surface to be ground 2A according to the desired profile and surface finish.

For this purpose, the machining head comprises an abrasive belt 11.

The material constituting said abrasive belt 11, and the grain (roughness) of said abrasive belt 11 may be chosen according to the nature of the material constituting the surface to be ground 2A and the desired result.

The abrasive belt 11 is guided along a belt path 12 which is defined, as is clearly visible in FIGS. 3 and 7, by a plurality of wheels 13, 14, 15 carried by said machining head 10, these including an applicator wheel 13 which is intended to press the abrasive belt 11 against the surface to be ground 2A in a first direction Y10, called the “penetration direction” Y10, which is transverse, and preferably perpendicular, to the main central axis X2.

Said abrasive belt 11, thus included within the machining head 10, is advantageously flexible so as to conform to the shape of the belt path 12, and more particularly so as to conform to the portions of the circumference of the wheels 13, 14, 15 which guide said abrasive belt 11, in particular the circumferential portion in an arc of a circle, here substantially in a semicircle, of the applicator wheel 13.

Advantageously, the applicator wheel 13 makes it possible to press the abrasive belt 11 in tangential contact against the surface to be ground 2A, and locally, i.e. in the zone of tangential contact with the surface to be ground 2A, drive the abrasive belt 11 in a movement which is in the opposite direction to the rotary circumferential movement of the part 2 to be ground. To this end, the applicator wheel 13 rotates in practice about its axis X13 in the same direction of rotation as the direction of rotation in which the part 2 of revolution rotates about its main central axis X2.

The penetration direction Y10 will correspond to the direction which allows the abrasive belt 11 to penetrate into the depth of the surface to be ground 2A, approaching the main central axis X2, with a predetermined depth of pass, so that that the machining action exerted by the abrasive belt 11 against the part of revolution 2 removes a radial thickness of material from said part of revolution 2, i.e. reduces the diameter of said part of revolution 2.

Said penetration direction Y10 is preferably orthogonal to the main central axis X2, i.e. contained in a plane normal to said main central axis X2.

According to a preferred variant, and as shown schematically in FIG. 7, in a plane normal to the main central axis X2, the point of contact 42 of the abrasive belt 11 with the surface to be ground 2A will be located such that the fictitious straight line Y10′ which is vectorially collinear with, i.e. parallel to, the penetration direction Y10 and which passes through said point of contact 42 is radial, i.e. secant and orthogonal to the central axis X2. Thus, the abrasive belt 11 will preferably be pressed perpendicularly against the part of revolution 2, here the cylinder 2, for better control of the depth of cut and good machining stability.

The machining head 10 also includes a belt-driving motor 16 of which the stator 17 is fixed to said machining head 10. Said belt-driving motor 16 is arranged to drive the abrasive belt 11 in motion along the belt path 12.

It will be noted that the machining head 10 comprises at least one support structure 50, which offers support to the wheels 13, 14, 15 of the belt path 12, and also to the stator 17 of the belt-driving motor 16.

Said support structure 50 can advantageously form a portion of a casing of the machining head 10, and/or serve as a support for casing panels 51 which clad said machining head 10, as can be seen in FIG. 2.

Preferably, the movement of the abrasive belt 11 takes place in the longitudinal direction of said abrasive belt 11, and in a direction opposite to the direction of the circumferential speed of the part of revolution 2, here of the cylinder 2, when said part of revolution 2 is driven in its rotational movement on its main central axis X2.

The belt-driving motor 16 is coupled, preferably via a gear reducer 18, here a reducer 18 forming a bevel gear, to at least one of the wheels 13, 14, 15 of the belt path, called “drive wheel”, which engages with the abrasive belt 11 in order to set said abrasive belt 11 in motion along the belt path 12.

According to a particularly preferred feature which could constitute an invention in its own right, and as can be seen in FIGS. 3, 4 and 7, the drive wheel is coincident with the applicator wheel 13, i.e. the applicator wheel 13 also fulfills the function of drive wheel, which improves the compactness of the machining head 10 and the reliability of the drive of the abrasive belt 11. For simple convenience of description, the same reference 13 can therefore be used to designate either the applicator wheel or the drive wheel.

The reducer 18 could, for example, transmit the belt-driving movement to the drive wheel 13 via a drive belt 31.

The assembly comprising the reducer 18 and the stator 17 of the belt-driving motor 16, within which assembly the stator 17 is preferably fixed to the casing of said reducer 18, is preferably fixed to the above-mentioned supporting structure 50, for example by means of screws.

The fixing of the assembly comprising the reducer 18 and the stator 17 can advantageously be carried out by means of a flange 19, which can be secured to the supporting structure 50 by means of screws, and which will have oblong holes 19A which will make it possible to adjust the relative position of the reducer 18, and more particularly of the reducer-18/stator-17 assembly, with respect to the axis X13 of the applicator wheel 13, so as to allow adjustment of the tension of the drive belt 31, such as can be seen in FIG. 3.

The abrasive belt 11 is advantageously inextensible in the direction in which said abrasive belt 11 is driven and moves within the belt path 12, i.e. here in the longitudinal direction of said abrasive belt 11, and this is so that said abrasive belt 11 can be tensioned within said belt path 12 and so that said abrasive belt 11 can be set in motion by exerting, here by means of the applicator wheel 13, a longitudinal traction on said abrasive belt 11.

The machining head 10 preferably also comprises a tensioning mechanism 20 making it possible to adjust the tension of the abrasive belt 11 within the belt path 12, and therefore in particular to guarantee the good adherence of said abrasive belt 11 on the wheels 13, 14, 15 of the belt path 12, in particular on the applicator wheel 13.

To this end, said tensioning mechanism 20 will preferably be arranged to be able to modify the position of the axis of one 14 of the wheels of the belt path 12 and maintain said axis in the chosen position, and may comprise for example for this purpose a pivoting linkage 21 placed under the control of an actuator 22 of the electric, pneumatic or hydraulic jack type, which actuator 22 is itself included on the machining head 10, and more preferably carried by the supporting structure 50, preferably by means of a pivot connection 22A which allows the barrel of said jack 22 to be articulated on said support structure, as is clearly visible in FIG. 3.

Furthermore, the corrective grinding device 1 further comprises a head movement system 23 which makes it possible to move the machining head 10 on the base 5 in a second direction X10, called the “feed direction” X10, which is transverse, and preferably perpendicular, to the penetration direction Y10, so that said machining head 10 can, along the main central axis X2, cover a so-called “useful feed stroke” L10.

In practice, when the device 1 is in place on the frame 3, the feed direction X10 is parallel to, i.e. vectorially collinear with, with the main central axis X2, so that the head movement system can move the machining head 10, and therefore the abrasive belt 11, parallel to said main central axis X2, and more particularly so that the head movement system 23 can cause the machining head 10 to move back and forth along the surface to be ground 2A, parallel to the main central axis X2, over a distance corresponding to the useful feed stroke L10.

It will be noted that, to define the feed direction X10, and more generally the arrangement of the components of the device 1, reference is made, for convenience of description and for a good understanding, to the main central axis X2 of the part 2 of revolution on which the corrective grinding device 1 is to operate, although said part 2 of revolution is distinct from the device 1 and external to the latter. Strictly speaking, it would therefore be possible, in an equivalent way, and in order to define the device 1 independently of the frame 3 and of the installation 4, and in particular in order to define, in absolute terms, the arrangement of the base 5, the position of the coupling members 6, and the orientation of the penetration direction Y10 and feed direction X10, to use a fictitious reference axis attached to the device 1, and therefore independent of the frame 3 and of the part of revolution 2, and made to coincide with the real main central axis X2 when the device 1 is in place on the frame 3.

The head movement system 23 preferably comprises at least one guide rail 24, which is fixed to the base 5 and extends in a straight line along the feed direction X10, in order to embody said feed direction X10. Said guide rail 24 is therefore parallel to the main central axis X2.

Engaged in translation on this guide rail 24 is at least one carriage 25, preferably a ball carriage 25, and preferably a pair of ball carriages 25, on which is fixed a plate 26 which carries the machining head 10, as is visible in FIG. 3.

Even more preferably, for better precision and more robust guidance, two guide rails 24 parallel to each other will be provided, these preferably being staggered along the penetration direction Y10, each of said guide rails 24 guiding a pair of carriages 25 which, as a whole, carry the plate 26 and therefore the machining head 10.

Preferably, the head movement system 23 is provided with a feed motor 27, separate from the belt-driving motor 16, in order to be able to move the machining head 10 along the base 5, in the feed direction X10.

Preferably, said feed motor 27 is included on the machining head 10.

Preferably, as is clearly visible in FIGS. 3 and 4, said feed motor 27 is for this purpose coupled to a pinion 28 which meshes with a rack 29, which is here preferably fixed to the base 5.

Thus, it is possible, by means of a control unit which controls the feed motor 27, to control the position and the speed of translational movement of the machining head 10 in the feed direction X10, and therefore along the main central axis X2, by means of a head movement system 23 having a particularly simple, compact and robust structure.

Preferably, the feed motor 27 is an electric motor.

The rack, for its part, preferably extends in a straight line, parallel to the guide rails 24.

Preferably, as is particularly visible in FIGS. 4, 5 and 6, the guide rails 24 are fixed on a plate 30 of the base 5, on a first face, here the upper face, of said plate 30, while the toothset of the rack 29 points on the side of a second face of the plate 30 opposite to the first face, here therefore the lower face of said plate 30.

Preferably, the belt-driving motor 16, and preferably the belt path 12, are located on one side of said plate 30, here facing the first face, forming the upper face, of said plate, while the feed motor 27 is located on the opposite side of the plate 30, facing the second face, here the lower face.

Such an arrangement of the plate 30, of the components of the machining head 10, and of the head movement system 23, contributes to the compactness of the device 1, to the effective support of the machining head 10 in particular against the effects of gravity, and to good stability of the machining head 10 during its movements in the feed direction X10.

According to the invention, the device 1 is arranged in such a way that, in orthogonal projection in a plane called the “base plane” P10 which is defined by the feed direction X10 and the penetration direction Y10, the projected surface of the abrasive belt 11 which is in the belt path 12 overlaps the projected surface of the stator 17 of the belt-driving motor 16, as is clearly visible in FIG. 5.

It will be noted that the upper face of the plate 30 supporting the guide rails 24 preferably advantageously coincides with the base plane P10, and therefore embodies said base plane P10.

Advantageously, as explained above, the at least partial axial superposition, of the stator 17 and of the abrasive belt 11 makes it possible to construct a machining head 10 which is particularly narrow, and which can therefore easily be inserted and moved within the frame 3, between the side uprights 3A, 3B, without interfering with the frame 3, and which can therefore reach all portions of the surface to be ground 2A.

Indeed, as can be clearly seen in FIGS. 5 and 6, the width W11 of the abrasive belt on the one hand, considered along the main central axis X2, or here, equivalently, along the feed direction X10, more particularly in the area of contact of the abrasive belt 11 with the surface to be ground 2A, and the width W17 of the stator 17 of the belt-driving motor 16 on the other hand, overlap at least partially, over a common axial range, and therefore advantageously share the same space along the main central axis X2, or here in an equivalent manner along the feed direction X10.

This sharing of the same common axial space has the effect of reducing the overall axial size of the machining head 10, considered in the feed direction X10, and therefore along the main central axis X2, since the belt-driving motor 16, and more particularly the stator 17 thereof, projects axially little, if at all, in the feed direction X10 and therefore in the direction of extension of the main central axis X2, with respect to the lateral edges of the abrasive belt 11.

It will be noted in this regard that, according to one possible embodiment, the width W17 of the stator of the belt-driving motor 16 could be less than the width W11 of the abrasive belt 11, so that the stator 17 would preferably be entirely contained axially, in the feed direction X10, within the axial range occupied by the abrasive belt 11.

According to another embodiment, such as that illustrated in the figures, the width W17 of the stator 17 will be greater than the width W11 of the abrasive belt 11. In this case, the width W11 of the abrasive belt 11 will preferably be entirely inscribed axially, in the feed direction X10, inside the width W17 of the stator, as is clearly visible in FIGS. 5 and 6.

More generally, of the two elements which are the abrasive belt 11 on the one hand, and the stator 17 of the belt-driving motor 16 on the other hand, the one that has the smallest width W11, W17 will preferably be entirely inscribed axially, in the feed direction X10 and therefore along the main central axis X2, inside the axial range occupied by the other of said two elements, the one that has the greatest width W17, W11, so that that, of said two elements 11, 17, the one which is the narrowest and occupies the smallest axial range does not protrude axially with respect to that one of said two elements 11, 17 that is axially the widest.

By way of indication, the width W11 of the abrasive belt 11 may for example be between 5 cm and 20 cm, preferably between 8 cm and 10 cm.

The width W17 of the stator 17 may for its part be preferably between 10 cm and 35 cm, more preferably between 15 cm and 25 cm, for example between 22 cm and 24 cm.

Preferably, the belt-driving motor 16 is an electric motor. The stator 17 can then preferably contain fixed field windings, intended to excite a rotor of the motor 16, which rotor can itself comprise either an electrically conductive, closed armature circuit, as is the case for an asynchronous motor, or permanent magnets, as is the case for a synchronous motor.

Preferably the feed motor 27, and more particularly the stator of said feed motor 27, here preferably the stator containing the fixed field windings of an electric feed motor 27, is arranged so that the projected surface of said feed motor 27, and more particularly of the stator of said feed motor 27, in the base plane P10 overlaps the projected surface of the abrasive belt 11, and, more preferably, overlaps both the projected surface of the abrasive belt 11 and the projected surface of the stator 17 of the belt-driving motor 16.

Thus, preferably, the feed motor 27, and more particularly the stator thereof, shares a common axial space with the abrasive belt 11, and the stator 17 of the belt motor 16, in the feed direction X10, and therefore along the main central axis X2. As is clearly visible in FIG. 6, the width W27 of the feed motor 27, and more particularly of the stator thereof, is superimposed at least in part on the width W11 of the abrasive belt, and on the width W17 of the stator 17 of the belt-driving motor 16.

For the reasons already explained above, this contributes to the compactness of the machining head 10, and to the capacity of said machining head 10 to reach and machine all the portions to be ground of the surface to be ground 2A.

Preferably, the belt-driving motor 16 and the feed motor 27, and more specifically their respective stators, are staggered relative to each other in a third direction Z10 which is normal to the base plane P10, and more particularly here are staggered vertically relative to each other, one, here the belt-driving motor 16, being above the plate 30, and the other, here the feed motor 27, being located below the plate 30, as can be seen in FIGS. 4, 6 and 7. By convention, the third direction Z10 is the direction which forms, with the feed direction X10 and the penetration direction Y10 a rectangular trihedron.

This staggering advantageously makes it possible to distribute said motors 16, 27 in a third direction Z10, here substantially vertical, which is transverse and preferably orthogonal to the feed direction X10, and therefore transverse or even orthogonal to the main central axis X2, this facilitating the ability of said motors 16, 27 to cohabit the same axial range in the feed direction X10, and therefore the same axial range along the main central axis X2.

Preferably, as is clearly visible in FIGS. 3, 4 and 7, the abrasive belt 11 is closed on itself so as to form a continuous loop which travels in a closed circuit along the belt path 12.

Such an arrangement whereby said abrasive belt 11 forms an endless loop advantageously makes it possible for the abrasive belt 11 to be driven, by means of the belt-driving motor 16, in a continuous and regular movement through the belt path 12, without it being necessary for example to interrupt or reverse said movement in order to periodically rewind the abrasive belt on a reel-type winding support.

Such an arrangement also makes it possible to use the whole of the abrasive belt 11, without waste, and guarantees progressive and relatively uniform wearing of the abrasive belt 11, and therefore progressive and controllable evolution of the machining conditions, which simplifies the obtaining of a flawless surface finish of the surface to be ground 2A.

Finally, such an arrangement makes it possible to keep a machining head 10 compact, since it is in particular not necessary to provide within said machining head a reserve spool of new abrasive belt and/or a recovery spool onto which to recover spent belt.

According to one possible embodiment, it could be envisaged for the belt-driving motor 16 to be located outside the belt path 12, in a direction Y10, Z10 transverse to the feed direction X10.

However, for greater compactness, the abrasive belt 11 forms a continuous loop which travels in a closed circuit along the belt path 12 around the stator 17 of the belt-driving motor 16, so that, in projection in a plane normal to the feed direction X10, here for example the plane defined by the second and third directions Y10 and Z10, the stator 17 of the belt-driving motor 16 is strictly contained within the perimeter delimited by the abrasive belt 11, as is clearly visible in FIGS. 3, 4 and 7.

Thus, in a plane normal to the feed direction X10, and therefore normal to the main central axis X2, the belt path 12 preferably forms, with respect to the stator 17, a closed peripheral belt path 12, which delimits an enclosure, embodied by the abrasive belt 11 which is present and which therefore describes said belt path 12, inside which enclosure the stator 17 fits entirely. For better visualization of this arrangement, the belt path 12 is shown in thick dotted lines in FIGS. 3, 5 and 7.

Advantageously, this arrangement proposed by the invention makes it possible to exploit the volume which is contained inside the belt path 12 to house the stator 17 of the belt-driving motor 16 therein, and thus makes it possible to reduce the size of the machining head 10.

Preferably, in the plane normal to the feed direction X10, the wheels 13, 14 and 15 which define the belt path 12 are also included within the closed contour delimited by said belt path 12.

It is preferably the same for the reducer 18, and also for the jack 22 and the linkage 21 of the tensioning mechanism 20.

Thus, the components necessary for driving the abrasive belt 11 preferably fall within the closed perimeter defined by said abrasive belt 11, in order to optimize the compactness of the machining head 10.

Conversely, in the plane normal to the feed direction X10, the feed motor 27 is preferably located outside the closed perimeter defined by the abrasive belt 11 present in the belt path 12. This makes it possible not to lengthen the belt path 12 unnecessarily, and therefore to preserve the compactness and inextensibility of the abrasive belt 11, and to limit the risks of said abrasive belt 11 loosening.

Preferably, as is clearly visible in FIG. 7, the belt path 12 describes, in the plane normal to the feed direction X10, a contour which is substantially in the shape of a rectangle and which encloses in particular the belt-driving motor 16 and the wheels 13, 14, 15.

The applicator wheel 13, which also forms the drive wheel, occupies a short side of the rectangle, so that the diameter of said applicator wheel corresponds to the width of said rectangle. The second wheel 14, which preferably belongs to the tensioning mechanism 20, has a smaller diameter and occupies a corner of the rectangle opposite the short side occupied by the applicator wheel 13. The third wheel 15, preferably freely rotating, also has a diameter smaller than that of the applicator wheel 13, preferably equal to the diameter of the second wheel 14, and occupies the last corner of the rectangle, along the same short side as the second wheel 14, to complete the layout of the belt path 12.

The long sides of the rectangle are preferably parallel to the penetration direction Y10, and the short sides parallel to the third direction Z10.

Moreover, in projection in the base plane P10, the lateral edges of the abrasive belt 11, which delimit the width W11 of said abrasive belt, are preferably both parallel to each other and parallel to the penetration direction Y10, and more preferentially orthogonal to the feed direction X10, and therefore orthogonal to the main central axis X2.

The belt path 12 is thus preferably orthogonal to the feed direction X10.

More preferably, the abrasive belt 11 engaged in the belt path 12 is such that, on the one hand, said abrasive belt 11 has a median plane PM11, which corresponds to the plane containing the imaginary line that the abrasive belt 11 describes and which is located equidistant from each of the two lateral edges of said abrasive belt 11 which form the limits of said abrasive belt 11 in the feed direction X10, and that, on the other hand, said median plane PM11, as is clearly visible in FIGS. 5 and 6, is normal to the feed direction X10, and therefore normal to the main central axis X2.

In this respect, it will be noted that the applicator wheel 13 is preferably mounted with the ability to rotate on the machining head 10 on an axis X13 which is vectorially collinear with, i.e. parallel to, the main central axis X2, and therefore preferably parallel to the feed direction X10.

More generally, the applicator wheel 13 is mounted with the ability to rotate on the machining head 10 on an axis X13 which is not orthogonal to, and is preferably vectorially collinear with, i.e. parallel to, the main central axis X2, i.e. on an axis X13 which is oriented in such a way that a plane normal to said axis X13 of the applicator wheel is transverse, and preferably normal, to the main central axis X2, and therefore to the feed direction X10.

Advantageously, this allows the applicator wheel 13 to press the abrasive belt 11 with a tangential approach “flat” against the surface to be ground 2A, and to cause the abrasive belt 11 to progress in the direction which corresponds to its width W11 when the machining head 10 moves in the feed direction X10, since the axis X13 of said applicator wheel 13 is and remains advantageously parallel to the feed direction X10 and to the main central axis X2 while the machining head 10 moves in the feed direction X10.

Advantageously, such an arrangement promotes the compactness of the machining head 10 and the uniformity of the machining.

In a manner known per se, the belt-driving motor 16 comprises a rotor which is mounted with the ability to rotate relative to the stator 17 about an axis called the “drive motor axis” Y16 so that the interaction between the stator 17 and the rotor which is created within the belt-driving motor 16 during an activation of said belt-driving motor 16 generates a torque which causes said rotor to rotate on itself relative to the stator 17, and more preferentially inside said stator 17, about said drive motor axis Y16.

In practice, since the stator 17 delimits a substantially cylindrical chamber receiving the rotor, the drive motor axis Y16 corresponds to the central axis of the stator 17 of the belt-driving motor 16.

The rotor is coupled to at least one of the wheels 13 of the belt path 12, called “drive wheel” 13, which is preferably coincident with the applicator wheel 13 as stated above, so that the rotor can transmit its rotation to said drive wheel 13 in order to drive the abrasive belt 11 in its abrasive movement.

Preferably, in a manner known per se, the rotor is in the form of an output shaft which makes it possible to connect the belt-driving motor 16 to the constituent elements of the kinematic chain for driving the abrasive belt.

Here, the rotor engages with the input of the reducer 18, which in turn, at the output of said reducer 18, transmits the rotational movement to the drive wheel 13, here for example via the drive belt 31 as can be seen in FIG. 3.

Preferably, the drive motor axis Y16 is oriented transversely relative to the main central axis X2, preferably so as to form, at least in the base plane P10, an angle of between 85 degrees and 95 degrees relative to said main central axis X2, and therefore relative to the feed direction X10. More preferably, said drive motor axis Y16 is oriented orthogonally with respect to the main central axis X2, so as to form an angle of 90 degrees with respect to said main central axis X2.

Preferably, the drive motor axis Y16 is contained in a plane normal to the main central axis X2, and therefore normal to the feed direction X10, and even more preferentially is parallel to the penetration direction Y10.

Here again, such an arrangement which provides for arranging the drive motor axis Y16 transversely to the main central axis X2 makes it possible to align the stator 17, and more particularly the largest dimension of said stator 17, in a transverse direction, preferably orthogonal to the main central axis X2, or even in a direction substantially radial to said main central axis X2, which makes it possible to minimize the lateral bulk of the machining head 10, along said main central axis X2.

Preferably, the drive motor axis Y16 is, in projection in the base plane P10, contained within the width W11 of the abrasive belt 11, so as to be located between the two lateral edges of the abrasive belt 11, and therefore to be located, along the main central axis X2, inside the axial range occupied by the abrasive belt 11, at least in the axial range of said abrasive belt 11 which corresponds to the contact zone at which said abrasive belt 11 touches the surface to be ground 2A.

Preferably, the drive motor axis Y16 is, in projection in the base plane P10, and at least in the axial range which corresponds to the zone of contact of the abrasive belt 11 with the surface to be ground 2A, or even preferably for the whole of the abrasive belt 11, centred on the width W11 of the abrasive belt, i.e. located at an equal distance from each of the two lateral edges which delimit said abrasive belt 11 along the main central axis X2.

Even more preferentially, the drive motor axis Y16 will be contained in the median plane PM11 of the abrasive belt 11.

Here again, the superimposition or even preferentially the centring of the drive motor axis Y16 with the abrasive belt 11 will make it possible to balance the machining head 10 and to distribute its bulk effectively, so as not to hinder the movements of the machining head between the side uprights 3A, 3B of the frame 3 either in one direction (for example to the right in FIGS. 1, 5, 6, 8A and 8B), or in the other direction (to the left in said figures).

For similar reasons, the feed motor axis Y27 will preferably be contained in a plane normal to the feed direction X10, and therefore normal to the main central axis X2, and more preferentially will be contained in the median plane PM11 of the abrasive belt 11.

Said feed motor axis Y27 will preferably be parallel to the penetration direction Y10.

According to a particularly preferential arrangement which corresponds to that illustrated in the figures, and which is particularly clearly visible in FIGS. 6 and 7, the drive motor axis Y16 and the feed motor axis Y27 will be parallel to each other and coplanar, so as to be staggered vertically in the same plane normal to the main central axis X2 and to the feed direction X10, more preferentially so as to be staggered vertically in the median plane PM11, and will preferably be parallel to the penetration direction Y10.

This will minimize the bulk of the machining head 10 along the main central axis X2 and will give the machining head 10 a good balance, which will promote the stability and uniformity of the operation of the head drive system 23.

Furthermore, the corrective grinding device 1 preferably comprises an adjustment mechanism 32 making it possible to adjust the depth of cut by which the abrasive belt 11 must penetrate into the part of revolution 2 to be ground, in the penetration direction Y10.

Preferably, the depth-of-cut adjustment is fixed for each new complete translation of the machining head 10 in the feed direction X10, i.e. said adjustment is constant for the same pass over the entire axial length of the surface to be ground 2A.

The adjustment mechanism 32 may comprise a slide 33 which is interposed between on the one hand the plate 26, which also preferably carries the feed motor 27, and on the other hand the portion of the machining head 10 comprising the abrasive belt 11, the belt path 12 and the belt-driving motor 16.

The position of the slide 33, and therefore the position of the applicator wheel 13 and of the abrasive belt 11, in the penetration direction Y10, relative to the base 5, and therefore the depth of cut, can be adjusted and identified by any appropriate system, for example by means of a vernier 34, as is particularly visible in FIGS. 3 and 7.

As an indication, the depth of cut may be between 0.02 mm (two hundredths of a millimetre) and 0.15 mm (fifteen hundredths of a millimetre), for example between 0.05 mm (five hundredths of a millimetre) and 0.10 mm (ten hundredths of a millimetre). The depth of cut will in particular be chosen to be sufficiently small to prevent the abrasive belt 11 from jamming against the surface to be ground 2A.

The available travel of the slide 33 in the penetration direction Y10 will preferably be greater than or equal to 1 cm, for example between 1 cm and 10 cm, preferably equal to 3 cm (+/−5 mm). Thus, there will be a good “reserve” to initially position the machining head 10 in the penetration direction Y10 with respect to the surface to be ground 2A, then to successively execute several passes, cutting gradually, over the successive passes, ever deeper into the radial thickness of the surface to be ground 2A.

It will also be noted that, for the final pass or passes for finishing, and more particularly for superfinishing, and which make it possible to polish the surface to be ground 2A by means of the abrasive belt 11 in order to give it its final surface finish, and in particular an arithmetic roughness Ra less than or equal to 0.4 μm or even equal to or less than 0.1 the abrasive belt can simply be brought into contact with the surface to be ground 2A, with a depth of cut of practically zero.

Preferably, the base 5 is formed by a beam 40.

Preferably, said beam 40 is a lattice beam, i.e. has an openwork structure within which a network of bars forms triangular structures, as can be seen in particular in FIGS. 3, 4 and 6. Such a lattice structure advantageously combines rigidity and lightness of weight.

The axial ends of said beam 40, i.e. the opposite ends of said beam 40 in the feed direction X10, which therefore correspond to the ends 5A, 5B of the base 5, are each provided with a coupling member 6, here each with a foot 7, 8, allowing said beam 40 to be fixed to the frame 3.

Preferably, the cross section of said beam 40 is larger in the central portion of said beam than at said ends 5A, 5B of said beam 40, in order to improve the rigidity of said beam 40 in said central portion.

Preferably, this overall variation in the thickness of the beam 40 is expressed at least, and possibly exclusively, in the third direction Z10, which makes it possible in particular to avoid any significant bending of said beam 40 under the weight of the machining head 10, in particular when said machining head 10 is halfway along the feed stroke and therefore halfway between the two ends 5A, 5B.

Preferably, as is clearly visible in FIGS. 3, 4 and 6, the beam 40 will, in a plane normal to the penetration direction Y10, have a trapezoidal shape, with its large base lying against, or even forming, the plate 30 which carries the guide rails 24 of the head movement system 23, and with its small base located at a distance from said plate 30, on the opposite side of said plate 30 to the guide rails 24 and the belt path 12.

Advantageously, by thus reinforcing the cross section of the beam 40 at its centre, said beam is made more resistant to bending under the effect of shear forces, such as in particular: the weight of the machining head 10, or the force of reaction of the part of revolution 2 to the pressing force with which the machining head 10 presses the abrasive belt against the surface to be ground 2A in the penetration direction Y10.

According to a preferential possible embodiment, the head movement system 23 comprises a template rail 41 which extends in length along the feed direction X10 in order to guide the machining head 10, and of which the deflection, considered radially to the main central axis, can be adjusted by deforming said template rail 41 by means of one or more set screws, for example in a range between −0.20 mm and +0.20 mm, so as to be able to make the feed path of the machining head 10 conform to a desired curved profile of the surface to be ground 2A.

Said template rail 41 can advantageously be positioned on the plate 30, between the guide rails 24, in order to cooperate with the plate 26 so as to force the applicator wheel 13 and the abrasive belt 11, to move (slightly) towards, or on the other hand, (slightly) away, in the penetration direction Y10, from the main central axis X2, depending on the direction of the curvature conferred on said rail by the set screws, as the machining head travels along the guide rails 24 along the base 5, and therefore along the main central axis X2 and therefore in the feed direction X10.

For this purpose, the plate 26 may comprise a runner which is mounted on the template rail 41 so as to slide along said template rail, without play, thanks to a suitable preload. The carriages 25 will then themselves be mounted slightly floating on the guide rails 24, with a slight functional clearance in the penetration direction Y10, which clearance allows the plate 26 to be just floating enough with respect to said guide rails 24 to be able to execute the slight displacements imposed by the deflection of the template rail 41.

It will be noted that, depending on the requirements, the curvature, or “bowing”, of the template rail 41 as conferred by the set screws, and therefore the corresponding deflection, may be positive, so as to confer on the surface to be ground 2A a profile that is outwardly curved, convex, forming a bulge with respect to the main central axis X2, or on the contrary negative, so as to give the surface to be ground 2A a hollow, concave profile, forming a depression with respect to the main central axis X2.

By way of indication, it is possible in particular to provide, within a calendering installation 4 according to the invention, a set of cylinders 2, 102, 202, 302 within which: the first cylinder 2 is slightly convex so as to be outwardly curved with a positive maximum deflection, considered in the middle thereof, i.e. at mid-length along the central main axis X2, which is between +0.10 mm and +0.15 mm, preferably equal to +0.12 mm or +0.13 mm (i.e. twelve to thirteen hundredths of a millimetre), the second cylinder 102 is straight, i.e. has zero deflection, the third cylinder 202 is slightly convex so to be hollowed with a negative maximum deflection of between −0.05 mm and −0.10 mm, preferably equal to −0.07 mm (seven hundredths of a millimetre), and the fourth cylinder 302 is convex, with a positive maximum deflection of between +0.15 mm and +0.20 mm, preferably equal to +0.18 mm (eighteen hundredths of a millimetre).

Depending on which of said cylinders 2, 102, 202, 302 is to be correctively ground, the base 5 will be fixed at the corresponding location on the frame 3 and the deflection of the template rail 41 will be adjusted accordingly.

Particularly preferentially, the corrective grinding device 1 comprises a single machining head 10 of which the useful feed stroke L10 is sufficient to allow said machining head 10 to cover, in one and the same continuous pass, the entire axial length of the surface to be ground 2A, considered along the main central axis X2, as is particularly visible in FIGS. 8A and 8B.

More preferentially, the machining head 10 is arranged in such a way as to be able to perform, along the base 5, successively a forward path in a first direction, from the first end 5A (FIG. 8A), which here corresponds to the limit of the useful feed stroke L10 closest to the first side upright 3A of the frame, as far as the second end 5B (FIG. 8B), which here corresponds to the limit of the useful feed stroke L10 closest to the second side upright 3B of the frame 3, then a return path in the opposite direction, from the second end 5B to the first end 5A, each of said paths covering the entire axial length of the surface to be ground 2A.

Preferably, as said single machining head 10 carries a single abrasive belt 11, each path therefore corresponds to a machining pass, and more particularly to a finishing pass.

Of course, it is possible to perform a series of several alternating paths, and more particularly to repeat the round trips in the feed direction X10, and therefore along the main central axis X2, from the first end 5A to the second end 5B and vice versa, in order to make as many passes as necessary, adjusting the depth of cut as needed between each path by means of the adjustment mechanism 32.

Advantageously, the use of one and the same machining head 10, and of one and the same corresponding abrasive belt 11, to carry out a continuous pass along the surface to be ground 2A, i.e. a pass which covers the entire axial length of said surface to be ground 2A in one and the same path, without interruption of machining or further rework operation, advantageously makes it possible to obtain a ground surface which has no irregularity, and in particular no projection or crest of material.

Preferably, the useful feed stroke L10 represents several times, for example at least five times, even at least ten times, the width W11 of the abrasive belt 11, for example between ten times and twenty times the width W11 of the abrasive belt 11.

By way of indication, the useful feed stroke L10 available for the machining head 10 in the feed direction X10, and therefore along the main central axis X2, may preferably be between 1500 mm and 2000 mm, more preferentially between 1700 mm and 1800 mm.

In practice, the aim will, for example, be to grind a length of cylinder which is preferably of the order of 1700 mm to 1750 mm, for example 1730 mm (+/−5 mm).

Such an amplitude of the useful stroke L10 will in particular be adapted to the preferential application of the invention to the corrective grinding of the cylinders of a calendering installation 4 designed to calender plies based on raw rubber, intended for example to be used in the manufacture of pneumatic tyres for vehicles.

The corrective grinding device 1 may of course comprise other components, for example a lubrication system comprising at least one spray nozzle designed to spray a lubricating fluid, such as water, into the zone of contact between the abrasive belt 11 and the surface to be ground 2A.

The device 1 will also comprise a control unit, preferably electronic, designed to control, and if necessary synchronize, the operation of the belt-driving motor 16 and of the feed motor 27, and possibly coordinate said motors 16, 27 with the main motor of the installation 4 which is used to rotate the part of revolution 2 on its main central axis X2.

The invention of course also relates to the use of a device 1 according to the invention for carrying out an operation of corrective grinding of a part 2 of revolution, such as a cylinder 2, 102, 202, 302, which has a central axis X2 and which is permanently mounted on the frame 3 of an installation 4 in such a way that said part of revolution 2 can be driven in rotation with respect to said frame 3 about its central axis X2.

Preferably, said installation 4 is a calendering installation, more preferably a calendering installation used to manufacture plies from one or more rubber-based materials.

Such an installation 4 preferably comprises for this purpose at least two parts of revolution 2, 102, 202, 302 forming counter-rotating calendering cylinders which define between them a nip through which the material or materials, here said rubber-based material or materials, to be calendered will pass.

In order to carry out the corrective grinding operation, the device 1 will first be fixed in a suitable location on the frame 3, facing the surface to be ground 2A of the part 2 of revolution, by temporarily securing the base 5 to said frame 3 by means of the coupling members 6, 7, 8, for the duration, and here more precisely just for the duration, which is necessary for said corrective grinding operation.

In doing so, care is taken to orient the base 5 so that the feed direction X10 of the device 1 is parallel to the direction of the main central axis X2 and so that the penetration direction Y10, transverse and preferably perpendicular to the feed direction X10, is directed towards the part 2 of revolution.

The configuration of the template rail 41, and therefore the curvature of the profile to be produced, can be adjusted before the base 5 is fixed to the frame 3, or indeed afterwards. In practice, it may be simpler, faster and more precise to adjust the configuration of the template rail 41 after having fixed the base 5 to the frame 3, since this makes it possible to carry out said adjustment of the template rail 41 while using as point of reference said frame 3 and/or unworn portions of the part 2 to be ground, for example using feeler-gauge comparators.

The depth of cut will then be adjusted by means of the adjustment mechanism 32, the operator being able to adjust this value with precision by means of the vernier 34.

The part of revolution 2 will then be rotated with respect to the frame 3, preferably at a predefined constant speed.

As an indication, the speed of rotation chosen for the part 2 of revolution may be such that the resulting circumferential speed at the surface to be ground 2A is between 5 m/min (five metres per minute) and 90 m/min (ninety metres per minute), or even between 20 m/min and 50 m/min, for example equal to 30 m/min +/−5 m/min.

The belt-driving motor 16 will be engaged so as to drive the abrasive belt 11 in motion, along the belt path 12, at a predetermined speed and in a direction which will correspond to the opposite direction to the circumferential speed of rotation of the surface to be ground 2A which results from the rotating of the part of revolution 2.

As an indication, the longitudinal speed of the abrasive belt 11, as imparted by the belt-driving motor 16, will preferably be greater than or equal to 1 m/s (one metre per second), preferably greater than or equal to 2 m/s, or even greater than or equal to 5 m/s (five metres per second) and for example between 2 m/s and 35 m/s, between 5 m/s and 35 m/s, or even between 5 m/s and 30 m/s.

The longitudinal speed of the abrasive belt 11 is in fact chosen to be relatively high, preferably greater, for example several times greater, in absolute value, than the circumferential speed of the surface to be ground 2A, so that the rapid movement of the abrasive belt 11 along the belt path 12, and in contact with the surface to be ground 2A, itself generates an effective abrasion movement, regardless of the speed of rotation of the part 2 of revolution.

Of course, the machining head 10 may be provided with means for adjusting the belt speed, which will make it possible to fix the setpoint speed for the abrasive belt 11 at a freely chosen value within one of the aforementioned ranges.

Once the part of revolution 2 and the abrasive belt 11 have reached their respective setpoint speeds, and have stabilized there, it will then be possible to trigger the feed motor 27 in order to cause the machining head 10, initially placed at one 5A of the ends of the base 5, to move in the feed direction X10.

The abrasive belt 11, while being kept in motion within the machining head 10 by the belt-driving motor 16, by means of the aforementioned setpoint speed, will thus engage with and travel along the part of revolution 2, itself kept in rotary motion, over the entire functional length of the surface to be ground 2A along the main central axis X2, and will thus gradually remove material from the surface to be ground 2A by straight turning.

Thus, at least one machining pass will be carried out by moving the machining head 10 in the feed direction X10 while the applicator wheel 13 presses the abrasive belt 11, still moving along its belt path 12, firmly against the surface to be ground 2A.

Once the machining head 10 has reached the other end 5B of the base 5, and the corresponding pass has thus been completed, it will be possible either to restart the machining head 10 in the opposite direction in the feed direction X10, in order to make a further pass, possibly after having modified the depth-of-pass setting, or, if the required surface finish has been attained, to stop the belt-driving motor 16, to stop the rotation of the part of revolution 2, and then dismantle the corrective grinding device 1 in order to transport it to another part to be ground.

In any case, at the end of the machining pass(es), the device 1 can be detached from the frame 3 by unlocking the coupling members 6, 7, 8 and removing said corrective grinding device 1 in order to free the corresponding location of the installation 4. Advantageously, this will allow the part 2, here the cylinder 2, 102, 202, 302, and more generally the installation 4, to be available once again in order to be able to resume its operation without delay.

As indicated above, the installation 4 may preferably comprise several parts of revolution 2, 102, 202, 302, such as cylinders, which are each mounted with the ability to rotate on the same frame 3.

Advantageously, the corrective grinding device 1 can then first be attached and fixed to a first location of the frame 3 so as to carry out a corrective grinding operation on a first of said parts of revolution 2, 102, 202, 302, then disassembled from the first location and transported and fixed to a second location of the same frame 3, remote from the first location, to carry out a corrective grinding operation on a second of said parts of revolution 2, 102, 202, 302.

In the installation 4 of FIGS. 1, 8A and 8B, these steps of installing the device 1, of grinding the cylinder, then of removing the device 1, can be repeated for each of the four cylinders 2, 102, 202, 302 successively.

Of course, the invention is in no way limited only to the embodiments described in the foregoing, a person skilled in the art being notably capable of isolating or combining one or another of the abovementioned features with one another, or of substituting equivalents therefor.

TRANSPORTABLE COMPACT CORRECTION DEVICE IN PARTICULAR FOR POLISHING CALENDERING CYLINDERS

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