EP0430207B1 - Contact roller for belt grinding machine - Google Patents

Description

The invention relates to a contact roller for belt grinding machines with a steel core and a jacket surrounding the latter, comprising an intermediate layer of elastically flexible material that at least partially covers the steel core and a plurality of outer elements made of a hard material that are arranged on the outer surface of the intermediate layer and are intended for contact with the grinding belt .

A contact roller is known from German utility model 1 953 917, in which the steel core is surrounded by a rubber jacket. This rubber jacket can be armored or provided with a different profile. The rubber jacket can also consist of layers of different Shore hardness.

On the other hand, there are contact rollers that have a steel jacket. In general, it can be stated in relation to the contact rollers known from the prior art that rollers with a relatively soft surface have a high tolerance for workpiece unevenness, but that they only permit a small amount of removal, since the sanding belt does not have the required Force can be pressed onto the workpiece. Such rollers are therefore not suitable for achieving high cutting performance on metallic workpieces. In contrast to this, rollers with a hard surface, for example a steel jacket, enable high stock removal per unit of time. However, they do not allow tolerance compensation for workpieces that are not completely flat.

To solve this problem, a pressure roller of the type mentioned at the outset has already been proposed in US Pat. No. 2,162,279, in which the outer elements consisting of the hard material are formed from blocks of hard rubber, cork or steel, which are attached to the closed, intermediate layer made of soft rubber are attached and can be moved independently. This pressure roller enables tolerance compensation for uneven workpieces. A disadvantage of this solution, however, is that, due to the independent mobility of these block-like elements, imbalances can occur on the one hand and on the other hand the elements are exposed to strong shear forces when trying to achieve high cutting performance. These can cause the elements to tear off the intermediate layer.

The invention has for its object to provide a contact roller of the type mentioned, which on the one hand enables high cutting performance and on the other hand tolerance compensation for uneven workpieces.

This object is achieved in that the elements made of the hard material are formed by closed rings which enclose the elastic intermediate layer and by ring grooves are axially separated from each other.

In the unloaded state, the rings form a smooth, hard cylindrical surface interrupted by grooves, which enables high removal per unit of time and is therefore particularly suitable for grinding metallic workpieces. On the other hand, the rings can deflect in the radial direction due to the elastic intermediate layer in the event of local unevenness or even a distortion of the workpiece, i.e. move radially relative to each other. This enables a tolerance compensation without reducing the grinding performance. This tolerance compensation is also possible without, for example, grinding or chamfering the edges of the workpieces, as is the case with contact rollers with a soft surface. Because the rings move radially as a whole, there is no imbalance when the contact roller rotates.

The rings are expediently made of steel. The grooves between the rings are used to cool the grinding belt. In order to prevent these ring grooves from being marked on the ground workpiece surface, the groove width and the width of the rings are dimensioned and the ring segments themselves are shaped such that - viewed over a circumferential line of the contact roller - the rings overlap several times. In a preferred embodiment, the ring grooves are continuously curved in such a way that they intersect an axis-normal central plane four times. For example, the edges of the rings can follow the contour of a cutting line, which results from a cut of each ring with a cylinder, the diameter of which compared to the ring diameter is large and its axis is perpendicular to the ring axis. This design of the rings ensures that the ring segments have no imbalance in themselves, even though their edges are not in a plane normal to the axis. This prevents the rings from tumbling.

The intermediate layer can consist of natural or synthetic rubber, the Shore hardness of this intermediate layer being able to vary to a relatively large extent.

According to a preferred embodiment, the intermediate layer does not consist of a compact cylinder, but instead of a plurality of ribs which are spaced apart and parallel to one another. The ribs are preferably oriented axially parallel. This formation of the intermediate layer facilitates the assembly of the rings on the intermediate layer.

The contact roller according to the invention combines the advantages of the previous different types of contact rollers. The contact roller according to the invention adapts to unevenness in the workpiece surface, thus enabling tolerance compensation. Tolerance fluctuations due to different workpiece thicknesses are compensated for without readjusting the roller.

Due to the smooth, hard surface of the contact roller, damage to the workpiece surface (except for the areas to be ground) can be avoided. Furthermore, the risk of damage to the grinding belt due to sharp or protruding workpiece edges is reduced, since the grinding belt lies against the hard, flat surface of the respective rings and is therefore good is supported. This means that sharp or protruding workpiece edges cannot penetrate the sanding belt.

A high chip removal is achieved while maintaining the above-mentioned advantages, since the abrasive grain lies against the steel jacket and cannot be pressed back into the rubber jacket like with a rubber roller. The heating of the grinding material is less, so that it warps less. The workpiece edges are also not accidentally ground round or at an angle.

The steel rings can in turn be coated on their outer peripheral surface, e.g. with a rubber layer.

Fig. 1

eine Seitenansicht der erfindungsgemäßen Kontaktwalze,

Fig. 2

einen Schnitt senkrecht zur Walzenachse entlang Linie II-II,

Fig. 3

einen achsnormalen Schnitt entlang Linie III-III in Figur 1,

Fig. 4

einen die Achse enthaltenden Schnitt durch die erfindungsgemäße Kontaktwalze und

Fig. 5

einen der Fig. 3 entsprechenden Schnitt durch eine abgewandelte Ausführungsform der Erfindung.

The following description in conjunction with the accompanying drawings explains the invention using exemplary embodiments. Show it:

Fig. 1

a side view of the contact roller according to the invention,

Fig. 2

a section perpendicular to the roller axis along line II-II,

Fig. 3

2 shows an axis-normal section along line III-III in FIG. 1,

Fig. 4

a section containing the axis through the contact roller according to the invention and

Fig. 5

3 corresponding section through a modified embodiment of the invention.

The contact roller for a belt grinding machine shown in FIG. 1 comprises a shaft or a core 10, which is surrounded by an intermediate layer 12 or segments made of rubber or a similar elastic material. This in turn is surrounded by a large number of ring segments 14, which are arranged axially next to one another, each separated by annular grooves 16. The ring segments 14 are preferably made of steel. Their circumferential surfaces aligned with one another form a cylindrical outer surface interrupted by the annular grooves 16.

Due to the arrangement of the ring segments 14 on the elastic intermediate layer 12, the ring segments 14 can move in the radial direction in the direction of the double arrow A in FIG. 1.

The shape of the ring segments 14 or the grooves remaining between them, which serve to cool the grinding belt, are shaped such that they are completely symmetrical with respect to the axis of rotation 18 of the contact roller. This can be seen in particular from FIG. 2. The cutting plane of Figure 2 runs exactly through the axis-normal center of a groove 16, i.e. in the middle between two axially normal planes 20 and 22 that delimit the groove. Each ground point on the circumference of a ring segment corresponds to a diametrically opposite, similar ground point, so that the ring segments 14 are completely balanced. They do not wobble around the axis of the contact roller.

Furthermore, it can be seen in FIG. 2 that the groove intersects the central plane, ie the sectional plane of FIG. 2, viewed four times over one revolution. The ring segments adjacent to this groove overlap in the circumferential direction, as is due to the different Hatching is indicated in Figure 2. This prevents the grooves 16 from forming on the workpiece surface during the grinding process.

FIG. 5 shows a modified embodiment of the contact roller according to the invention, wherein the intermediate layer does not consist of a closed cylindrical layer, but is formed by four ribs 12 ′ which are arranged on the core 10 with the same spacing from one another. The material of the ribs 12 ′ corresponds to the material of the intermediate layer 12 in the embodiment according to FIGS. 1 to 4. All other elements of the contact roller according to FIG. 5 correspond to those of the embodiment according to FIGS. 1 to 4. The solution shown in Figure 5 has the advantage that the rings or ring segments 14 can be assembled more easily.

Claims (8)

1. A contact roller for belt sanding machines, comprising a steel core (10) and a jacket surrounding the latter, comprising an intermediate layer (12, 12') of elastically resilient material at least partially covering the steel core (10) and a plurality of outer elements (14) of a hard material disposed on the outer surface of the intermediate layer (12, 12') and intended to bear against the sanding belt,
   characterised in that the hard material elements are formed by closed rings (14) which enclose the elastic intermediate layer (12, 12') and are disposed axially side by side but separated from one another by annular grooves (16).
2. A contact roller according to claim 1,
   characterised in that the rings (14) consist of steel.
3. A contact roller according to claim 1 or 2,
   characterised in that the width of the grooves (16) and the width of the rings (14) is so dimensioned that adjacent rings (14) - as considered in the peripheral direction of the contact roller - repeatedly overlap.
4. A contact roller according to claim 3,
   characterised in that the edges of the rings (14) are continuously curved in such manner and the distance between two adjacent rings (14) is so selected that the annular groove (16) extending between them intersects an axis-normal central plane (II-II) four times.
5. A contact roller according to claim 4,
   characterised in that the edges of the rings (14) follow the contour of a line of intersection resulting from intersection of the rings (14) by a cylinder whose diameter is large compared with the ring diameter and whose axis extends at right angles to the ring axis.
6. A contact roller according to any one of claims 1 to 5, characterised in that the intermediate layer consists of a plurality of ribs (12') which are disposed in spaced relationship and parallel to one another on the core (10).
7. A contact roller according to claim 6,
   characterised in that the ribs (12') extend in axis-parallel relationship.
8. A contact roller according to any one of claims 2 to 7, characterised in that the steel rings (14) are coated with another material, e.g. rubber, on their outer peripheral surface.

Images