EP0246383A1 - Process and apparatus for manufacturing rotating polishing tools - Google Patents

Abstract

Polishing tools comprising a moulded base (1) in which are embedded the tails of polishing elements (3) consisting of wires, tufts, braided fabrics, pieces of cloth, pieces of leather, or various sheets which are looped around a rigid retaining wire (7) which can be deformed into a continuous double strip wound in adjacent turns around a core. <IMAGE>

Description

The present invention relates to polishing tools for rotary machines, as well as a method and a machine for their manufacture.

Some rotary polishing tools are in the form of discs or rollers in which the polishing elements, formed of fibers, threads, wicks, braids, fabrics, skins or sheets of flexible or flexible material, are arranged radially around a rigid base tubular which allows the attachment of the tool to a spindle of the machine. Others are in the form of pads with a base in the shape of a washer from which the polishing elements emerge perpendicularly, an axial tip perpendicular to the disc protrudes on the face of the disc opposite to the polishing elements and allows the joining of the tool at the end of a rotary machine clamp.

Conventional tools in the form of discs or rollers are generally manufactured by assembling sectioned fibers, wires, rovings or braids arranged radially around a tubular core in radial stacking, then pressed and crimped between two flanges.

This method does not lend itself well to industrial manufacture and, moreover, the fixing of the polishing elements is often defective, which leads to premature deterioration of the tools.

Conventional tools in the form of pads are generally manufactured like brushes, by implanting tufts of polishing elements in the cells of a base.

This method also lends itself poorly to industrial manufacture, and the tufts of elements of polishing are often insufficiently maintained in the base, which causes uneven wear of the tools.

When using polishing elements consisting of pieces of fabric, skin or sheets of various flexible or flexible materials, such as non-woven or synthetic material, they are cut into rings which are stacked to form discs or rollers, but in this case the tools have a certain rigidity because it is the edge of the washer which works and the tool only has flexibility laterally, and not peripherally, which leads to lateral deformation of the tool when pressing on the object to be polished. We have therefore sought to overcome this drawback by cutting such polishing elements into strips which are used in tufts like fibers and the like, with the aforementioned drawbacks.

In general, conventional polishing discs are used on spindle polishers with diameters differing from one user to another, driven at speeds imposed by the material to be polished and the diameter of the disc. On the same spindle there are usually several stacked polishing discs made up of different cotton elements, braided or tampico sisal rope or chamois or any other material. To ensure the drive of these discs they must be compressed by an energetic clamping system against each other, which has drawbacks due to the fact that, depending on the person compressing and the attention which is brought to it may the number of discs on the spindle differ from one operation to another, and in order to obtain a density not too high, it is necessary to mount between each disc spacers or washers of different thickness.

It is common in polishing workshops for a person to be specifically assigned to mounting the polishing discs, this work being both delicate and relatively long.

Conventional polishing discs are made from a number of polishing elements in a thickness which is always approximately the same. The fixing of these elements to the hub of the disc requires in all cases a very strong compression, either around a rivet, or by pressing stapling, clamping in metal claws which are closed under strong pressure on the elements. This has the disadvantage that the density of the material at the periphery and at its center around the hub are so different that the disc is not always usable throughout its height. Another drawback stems from the fact that, when stacking discs that are leveled individually, therefore not strictly at the same height, a roll of density is obtained, which is not homogeneous, decreasing from a very hard center and of diameter which is not strictly identical over its entire length.

These drawbacks can cause significant damaging heating of the polishing material and of the polished material. In addition, the differences in diameter, in a roller made up of several stacked discs, lead to an accumulation of paste in the parts of smaller diameter or the valleys thus hollowed out, and in the operations of polishing of non-planar parts, it follows from the deposits of dough in the hollow of the pieces, deposits which must then be removed using specific washes.

Conventional polishing discs of this type are described in particular in US-A-3,115,730.

The object of the invention is to produce rotary polishing tools in a single piece of unlimited width which do not have the aforementioned defects of conventional tools, and which are particularly suitable for industrial manufacturing, with lower cost and better qualities. mechanical, especially with regard to concerns flexibility and regularity of wear.

The invention relates to rotary polishing tools in the form of discs, rollers or pads, each comprising a rigid base which holds by the heel a plurality of polishing elements formed of fibers, threads, locks, braids, fabrics, skins. or sheets of flexible or flexible material, natural or synthetic, the polishing elements being arranged in a strip, with at least one layer folded astride a rigid deformable retaining wire, wound in contiguous turns; tools characterized in that the wire, with the heel of the polishing elements which surrounds it, are embedded by molding in a hard base serving as a means for mounting the tool on the spindle of a rotary machine.

In such tools, the strip is advantageously gathered along the holding wire, which gives multidirectional flexibility at the active periphery of the tool.

A subject of the invention is also a method of manufacturing such polishing tools, characterized in that the polishing elements are placed side by side to form a continuous flat strip of constant width and desired thickness, in that a continuous holding wire is placed in the middle and in the axis of this flat strip, in that the free edges of the strip are folded around the wire, to form a double strip which is wound in contiguous turns around of a core, in that the wound strip is cut into sections each corresponding to a polishing tool, and in that the sections kept spirally contiguous are joined together by molding the wire and the heels of the surrounding polishing elements the wire, with the formation of a base serving as a means for mounting the tool on the spindle of a rotary machine.

In one embodiment of this method, we wraps the double strip with its wire, in continuous turns of the same diameter along a helix, to form a disc or roller with tubular base of desired width.

As a variant, the double strip is wound with its wire, in turns of increasing diameter in a spiral, to form a disc or pad with a disc-shaped base.

More particularly when using polishing elements constituted by strands or sections of fibers and the like, it is advantageous to glue the middle part of the strip on either side of the wire before folding it around the wire and join the glued parts together to form the heel of the polishing elements and leave the close edges of the strip free.

Polished polishing elements are obtained at lower cost by arranging them in several superimposed bands which are folded around the same retaining wire, and / or by gathering the folded band or bands along the straight wire. before winding around a core.

In order to obtain regular action tools, it is generally advantageous to level off the polishing elements to the same length, in other words at a constant distance from the base.

To obtain more or less dense tools, the coils are held against each other at the desired degree of compression during the molding of the base.

The invention also relates to a machine for the manufacture of such tools, implementing the method which is the subject of the invention, machine characterized in that it comprises a device for continuous supply of polishing elements and arrangement of these elements in a continuous strip with at least one layer, a device for supplying rigid, deformable retaining wire, in the axis of the strip, a device for folding the edges of the strip over each other around the wire, a device for winding the wire surrounded by the folded strip around a core, a device for cutting the strip into sections each corresponding to a tool, and a device for molding a base forming a plastic hub coating the heel of the polishing elements surrounding the wire, leaving the edges of the strip free and holding the turns against each other.

For certain applications, such a machine advantageously comprises a device for depositing a strip of adhesive in the axis of the strip, before folding, and rather before than after removing the median retaining wire. Such a tape of adhesive can be deposited in liquid or pasty form, by the conventional means of spraying casting, coating, or transfer roller, or even in the form of a solid tape of adhesive. The adhesive can be of the self-adhesive or even iron-on type. In the latter case, it may be useful to provide for the passage of the folded strip between two heated pressure rollers, otherwise the bonding will be carried out simultaneously with the molding, under the action of the hot plastic material.

When it is desired to crumple the strip along the retaining wire before winding around the core, the machine according to the invention will also include a conventional pleating device, for example of the type with two trains of rolls for driving the strip, spaced apart one from the other, the upstream train ensuring a faster drive than the downstream train, with compaction of the gathered band on the wire between the two trains.

To obtain a continuous strip of polishing elements consisting of separate strands, arranged parallel to each other and transversely to the axis of the strip, a machine according to the invention will advantageously include a device for drawing continuous threads from one or more supply coils, transversely to a temporary support member and conveyor belt, the pulled son being cut into strands of the same length by an integrated cutting member before their strip drive.

• - la figure 1 est une vue schématique, en pers­pective, d'un disque de polissage suivant l'invention ;
• - la figure 2 est une vue schématique, en pers­pective, d'un tampon de polissage suivant l'invention ;
• - la figure 3 est une vue schématique, en coupe diamétrale, du disque de la figure 1 ;
• - la figure 4 est une vue schématique, en coupe diamétrale, du tampon de la figure 2 ;
• - la figure 5 est une vue en perspective d'un diagramme fonctionnel des dispositions constructives d'une machine suivant l'invention, de fabrication de disques ou rouleaux de polissage à partir de fibres ou analogues, suivant les étapes du procédé de l'invention ; et,
• - la figure 6 est une vue analogue à celle de la figure 5 d'une machine, suivant l'invention, de fabrication de disques ou tampons de polissage à partir de bandes de tissu ou analogue.

The invention will be better understood on reading the detailed description of several examples of embodiments of the invention illustrated by the appended drawings in which:

• - Figure 1 is a schematic perspective view of a polishing disc according to the invention;
• - Figure 2 is a schematic perspective view of a polishing pad according to the invention;
• - Figure 3 is a schematic view, in diametral section, of the disc of Figure 1;
• - Figure 4 is a schematic view, in diametral section, of the pad of Figure 2;
• - Figure 5 is a perspective view of a functional diagram of the constructive arrangements of a machine according to the invention, for manufacturing polishing discs or rollers from fibers or the like, according to the steps of the method of the invention ; and,
• - Figure 6 is a view similar to that of Figure 5 of a machine, according to the invention, for manufacturing polishing discs or pads from strips of fabric or the like.

In these figures, the corresponding elements are designated by the same reference numerals.

• a) un noyau ou embase tubulaire 1 en matière plastique moulée creusée d'un canal axial 26 à section hexagonale permettant sa fixation sur une broche de forme complémentaire d'une machine de polissage rotative, et
• b) une corolle d'éléments de polissage consti­tuée par une bande continue 3 de tissu, peau, ou feuille de matière naturelle ou sythétique, repliée sur un fil 7 de maintien de fer ou autre métal déformable, ou de matière plastique, et enroulée autour de l'embase 1 en spires jointives, serrées les unes contre les autres et formant une hélice. Le fil 7 et la partie de bande 3 l'entourant sont enrobés dans la matière plastique de l'embase 1. Les bords de la bande 3 repliée sont libres et constituent la surface active cylindrique de l'outil. La bande 3 est froncée le long du fil 7 et les replis qu'elle présente assurent une flexibilité dans pratiquement toutes les directions. Ce froncement est, de préférence, supérieur à celui qui est nécessaire pour enrouler la bande sur un axe perpendiculaire à son plan. Ainsi, le bord libre de la bande présente des plis qui augmentent la surface de travail en lui communiquant aussi plus de sou­plesse.

The polishing disc represented in FIGS. 1 and 3 essentially comprises:

• a) a tubular core or base 1 made of molded plastic hollowed out with an axial channel 26 of hexagonal section allowing it to be fixed to a spindle of complementary shape of a rotary polishing machine, and
• b) a corolla of polishing elements constituted by a continuous strip 3 of fabric, skin, or sheet of natural or synthetic material, folded over a wire 7 for holding iron or other deformable metal, or of plastic material, and wound around the base 1 in contiguous turns, pressed against each other and forming a helix. The wire 7 and the band portion 3 surrounding it are embedded in the plastic of the base 1. The edges of the folded band 3 are free and constitute the cylindrical active surface of the tool. The strip 3 is gathered along the wire 7 and the folds which it presents ensure flexibility in practically all directions. This gathering is preferably greater than that which is necessary to wind the strip on an axis perpendicular to its plane. Thus, the free edge of the strip has folds which increase the working surface while also giving it more flexibility.

• a) une embase 2 moulée en forme de rondelle ou plateau circulaire duquel fait saillie axialement un téton à section hexagonale 27 permettant la préhension de l'outil par une pince classique de forme complémentaire d'une machine de polissage rotative, et
• b) une nappe annulaire d'éléments de polissage 4 constituée par des brins de fibres, ou des fils, mèches, tresses de matériaux naturels ou synthétiques disposés côte à côte et repliés autour d'un fil de maintien 7 en fer ou autre métal déformable, ou en matière plastique, en une bande double continue enroulée en spirale à spires jointives autour d'un évidement axial cylindrique. Le fil 7 et la partie des brins d'éléments de polissage 4 l'en­tourant sont enrobés dans la matière plastique de l'em­base 2. Les extrémités libres des brins repliés consti­tuent la surface active plane de l'outil.

The polishing pad shown in FIGS. 2 and 4 essentially comprises:

• a) a base 2 molded in the shape of a washer or circular plate from which an axially protruding stud 27 with hexagonal section 27 allows the gripping of the tool by a conventional pliers of complementary shape of a rotary polishing machine, and
• b) an annular ply of polishing elements 4 constituted by strands of fibers, or threads, rovings, braids of natural or synthetic materials arranged side by side and folded around a retaining wire 7 of iron or other deformable metal , or plastic, in a continuous double strip wound in a spiral with contiguous turns around a cylindrical axial recess. The wire 7 and the part of the strands of polishing elements 4 surrounding it are coated in the plastic material of the base 2. The free ends of the folded strands constitute the flat active surface of the tool.

The functional diagram of FIG. 4 illustrates an embodiment of both the process and the ma which are the subject of the invention.

Fibers or the like 28 drawn from an unwinding reel 21 are cut into strands of equal length by a cutting device 29,30 and aligned side by side to form a continuous strip 5 of constant width, for example on a conveyor belt classic, not shown. In the axis of the strip 5, a tape 18 of adhesive adhered by pressure from a unwinding reel 25 is deposited. Still in the axis of the tape 18, a continuous holding wire 7 of iron or the like is brought in. of an unwinding reel 24. Two opposing side drums 8,8ʹ fold the free edges of the strands 28 of the strip 5 against each other and glue them around the wire 7 to form a double strip 13 which is wound in a helix with contiguous turns 8 around a mandrel 14. A cutting device 16, 17 cuts the double strip 13 when the desired number of turns 8 has been wound around the mandrel 14. The helix formed by the wound turns is then transferred to a conventional mold, not shown, where it is pressed axially during the injection of plastic material to form a tubular base similar to that referenced 1 in FIGS. 1 and 3.

In the variant of the functional diagram of FIG. 6, two ribbons of fabric or the like 19,20, respectively coming from unwinding reels 22,23, are superimposed to form a continuous strip 6 with two layers of constant width. In the axis of the strip 6 is deposited a continuous holding wire 7 of iron or the like coming from an unwinding reel 24. Two lateral deflectors 9,9ʹ fold the free edges of the strip 6 around each other wire 7 to form a double strip 12 with four layers. The strip 12 then passes over a first train of drive rollers shown diagrammatically by a single roller 10 in FIG. 6, then over a second train of drive rollers further downstream shown diagrammatically here by a single roller 11. The train of rollers 10 spins at a speed greater than that of the roller train 11, which causes the strip 12 to gather along the wire 7. The gathered strip 12 is then wound in a flat spiral with contiguous turns 9 around a mandrel 15. When the wafer formed by the spiral reaches the desired diameter, the strip 12 is sectioned with a cutting device 16, 17. The wafer is then transferred to a conventional mold, not shown, where it is kept pressed radially during the injection of plastic material to form a flat base similar to that referenced 2 in FIGS. 2 and 4. Depending on the nature of the bands 19 and 20, it may be necessary to keep the folded edges forming the strip 12 pressed against each other until the spiral winding. Alternatively, the strips 19 and 20 can be glued axially (Figure 6) as in the diagram in Figure 5 at 18.25.

Of course, the invention is in no way limited to the embodiments and variants described and shown, on the contrary it encompasses all the adaptations and interpretations accessible to those skilled in the art.

This is how the invention has been described with respect to two examples of tools with polishing elements of the same kind, strands for Figures 1,3,5 and band for Figures 2,4,6, but it is also possible, according to the invention, to produce tools with various polishing elements, in particular strands and strip, for example by superimposing a continuous strip of fabric such as 20 of FIG. 6 on the fiber strip 5 of FIG. 5 between the application of adhesive 18 and the retaining wire 7.

Unlike conventional polishing discs, the polishing tools according to the invention have advantages deriving from the fact that they are not made of individual flanges joined together, but of a single piece whose density is adapted as desired at the proposed work.

The manufacturing method according to the invention involving a polishing material in continuous spirals, in combination with a rigid plastic hub which encloses the assembly, no longer requires untimely compression since it is no longer necessary to staple it or to take it in claws. Thus we obtain a modular density block, directly usable without specific mounting or clamping on the spindle. This avoids overheating and differences in diameter along the tool since the leveling to bring the disc to the diameter is carried out in a single block, which ensures the regularity of the disc. By way of example, for polishing table cutlery, knives and the like, according to a conventional method, a complete shaft of polishing discs was used for polishing and finishing 7,800 spoons. With a polishing tool in one piece, according to the invention and the same base material, polish between 17,000 and 19,000 spoons. The absence of overheating of the tool gives a much higher quality finish, possibly making it possible to eliminate additional brushing or polishing steps, which leads to cost advantages, speed of execution and reliability.

Claims (14)

1. Rotary polishing tools in the form of discs, rollers or pads, each comprising a rigid base (1,2) which holds by the heel a plurality of polishing elements (3,4) formed of fibers, threads, wicks, braids, fabrics, skins or sheets of flexible or flexible material, natural or synthetic, the polishing elements (3,4) being arranged in a strip (5,6), with at least one layer folded astride a retaining thread rigid deformable (7), and wound in contiguous turns (8,9); tools characterized in that the wire (7), with the heel of the polishing elements (3,4) which surrounds it, are embedded by molding in a hard base (1,2) serving as a hub for mounting the tool on the spindle of a rotary machine. 2. Tools according to claim 1, characterized in that the strip (6) is gathered (10,11) along the wire (7). 3. A method of manufacturing polishing tools according to one of claims 1 and 2, characterized in that the polishing elements (3,4) are placed side by side to form a continuous flat strip (5,6) of constant width and desired thickness, in that in the middle and in the axis of this flat strip a continuous retaining wire (7), in that the free edges of the strip (6 ) around the wire (7), to form a double strip (12, 13) which is wound in contiguous turns (8,9) around a core (14,15), in that the strip is cut wound in sections each corresponding to a polishing tool, and in that the sections held spirally contiguous to one another are joined together by molding the wire and the heels of the polishing elements surrounding the wire, with the formation of a hard base serving as a hub (1,2) for molding the tool on the spindle of a rotary machine. 4. Method according to claim 3, characterized in that the double strip (13,13) is wound with its wire (7) in continuous turns (8) of the same diameter along a helix to form a disc or roller with tubular base (1) of desired width. 5. Method according to claim 3, characterized in that the double strip (12) is wound with its wire, in turns (9) of increasing diameter in a spiral, to form a disc or pad with a disc-shaped base. (2). 6. Method according to one of claims 3 to 5, characterized in that glue (18) the middle part of the strip (13) on either side of the wire (7) before folding it around the wire and join the glued parts to form the heel of the polishing elements and leave free the close edges of the strip (13). 7. Method according to one of claims 3 to 6, characterized in that there are the polishing elements (19,20) in several superimposed strips which are folded around the same wire (7). 8. Method according to one of claims 3 to 7, characterized in that the gathered band or bands folded along the straight wire (7) before gathering it around a core ( 15). 9. Method according to one of claims 3 to 8, characterized in that the free ends of the polishing elements are leveled (3,4) at the same distance from the base (1,2). 10. Method according to one of claims 3 to 9, characterized in that the turns (8,9) are kept against each other during the molding of the base (1,2). 11. Machine for manufacturing polishing tools according to one of claims 1 and 2, implementing a method according to one of claims 3 to 10, characterized in that it comprises a device for continuously supplying polishing elements (3,4) and for arranging these elements in a continuous strip (5,6) with at least one layer, a device for supplying (24) in rigid, deformable retaining wire (7), in the axis of the strip (5,6), a device for folding (8,9) the edges of the strip (5,6) one on the other around the wire (7), a device for winding (14,15) the wire surrounded by the folded strip (12,13) around a core (14,15), a device for cutting the strip (12,13) in sections each corresponding to a tool, and a device for molding a base (1,2) forming a plastic hub covering the heel of the polishing elements (3,4) surrounding the wire (7) , leaving the edges of the strip free, and holding the turns against each other. 12. Machine according to claim 11, characterized in that it comprises a device (25) for depositing a tape of adhesive (18) in the axis of the strip (5) before folding. 13. Machine according to any one of claims 11 and 12, characterized in that it comprises a gathering device (10,11) of the strip along the wire (7) before winding around the core (15). 14. Machine according to any one of claims 11 to 13, characterized in that it comprises a device for forming a continuous strip (5) of polishing elements, consisting of strands (28) separated, arranged in parallel between them and transversely to the axis of the strip (5), by drawing continuous threads from at least one supply reel (21), transversely to a member for temporary support and conveyance in strip, the drawn threads being cut into strands of the same length by an integrated cutting member (30) before their strip drive (5).

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