EP2015898A1

EP2015898A1 - Machine for surface treatment, such as grinding or polishing

Info

Publication number: EP2015898A1
Application number: EP07722601A
Authority: EP
Inventors: Nina Himmer
Original assignee: Amanda Patent and Licensing SIA
Current assignee: Amanda Patent and Licensing SIA
Priority date: 2006-05-11
Filing date: 2007-05-10
Publication date: 2009-01-21
Also published as: WO2007131505A1; CN101443159A

Abstract

The present invention relates to a machine for surface treatment, such as grinding or polishing, of a workpiece and comprises a rotating cylinder (1 , 19). On the cylindrical face, a number of grinding or polishing modules (17, 18) are provided that comprise hold-back means, preferably in the shape of brushes (13). The invention is characterised in that the brushes (13) extend outwards and forwards relative to the direction of rotation of the rotating cylinder. Hereby it is accomplished that, by a combination of the rotation of the cylinder and the movement of the workpiece in the direction of conveyance of the apparatus, the grinding means establish contact with the end face (101 ) on the workpiece (100) to the effect that grinding or polishing of the end face (101 ) is obtained.

Description

Machine for surface treatment, such as grinding or polishing

The invention relates to a machine for surface treatment, such as grinding or polishing of workpieces and comprising a rotating cylinder having a number of treatment modules that extend outwards and away from the cylinder face and comprising at least one piece of grinding cloth.

Such machine is known ia from WO 2004/103643 describing a grinding apparatus with rotating grinding and brush modules comprising an elongate body part, at least one grinding cloth protruding from the body part, and a plurality of bristles that protrude from the body part in essentially the same direction as the grinding cloth.

Experience has shown that such bristles provide good grinding of essentially flat workpieces of preferably wood or metal; however, a problem exists in the context of the known grinding bristles in that the bristles do not always provide a pressure force on the rear side of the grinding cloth which is sufficient for the grinding cloth to remain in abutment on the workpiece to be grinded. This is particularly pronounced when workpieces of a certain thickness are to be grinded and which have faces of a certain expanse transversally of a conveyor belt for the workpieces, said grinding means being exclusively in contact with the edge and thus do not manage to grind the end faces/side faces. This is particularly pronounced in cases where the edges that are first conveyed past the grinding means are sharp.

From EP 1 215 010 B1 a grinding machine is known in which a number of forwardly sloping grinding modules on a chain conveyor are arranged. Due to the translatory movement the grinding cloth will, in practice, process only the lower and upper edges of the workpiece. The end face as such does, practically speaking, not undergo surface treatment. It is the object of the invention to provide a rotating grinding or polishing machine that ensures that also the end faces/side faces on workpieces of a certain thickness are grinded by being taken through the grinding machine.

According to the invention, this is accomplished in that hold-back means are provided that comprise elastic lamellae or brushes that are embedded in proximity of the cylinder face, from where they extend to a respective grinding cloth in directions that - seen in the direction of rotation - are situated in front of an axial plane through the embedding of the hold-back means at the cylinder face.

Preferably the hold-back means are bristles that extend outwards and forwards relative to the direction of rotation on the rotating brush.

Owing to the treatment modules according to the invention rotating about the axis of the cylinder and due to the hold-back means being forwardly oriented, the hold-back means, eg the bristles, will support the grinding cloth to the effect that it is pulled up above a side edge of the body, while simultaneously the hold-back means are pressed rearwards relative to the direction of rotation. When the end face has been treated, the surface treatment of the horizontal surface of the workpiece continues as described in WO 2004/103643.

Preferably the grinding cloth extends a small expanse, radially further than the hold-back means, such as the bristles.

The hold-back means need not be bristles, but may also be several pieces of grinding cloth, or they may be nylon brushes that have embedded grinding grains. Albeit, in the following, the hold-back means will be designated bristles, they may thus very well be configured in other ways. According to a particularly preferred embodiment, the bristles extend at an angle of between 10°-60°, an more advantageously at an angle of between 25°-45° relative to the radius of the grinding brush when the brush module is mounted on the cylinder.

According to a further embodiment, the brush module comprises a longitudinally extending guide that extends from the upper side of the brush module and extends into the brush module and is configured for receiving a grinding element that protrudes from the body part, where the body part and the grinding element are provided with complementary, mechanical interconnection means, whereby the grinding element is releasably mounted on the body part. Hereby the grinding cloth can be mounted on the body part of the brush module by being, in a simple manner, shifted axially into the groove. Simultaneously this construction ensures that the grinding cloth is not swung out of the brush module when it is mounted on a grinding brush that rotates.

According to a further embodiment the brush module comprises a longitudinally extending groove that extends centrally on the upper side of the brush module and extends into the brush module and is configured for receiving the plurality of brushes, where the brushes and the body part are provided with complementary, mechanical interconnection means to the effect that the grinding element is releasably mounted on the body part. Hereby it is accomplished that the brushes can be changed and further that it is an option to provide brushes secured to a fitting with a bead which is complementary with the longitudinally extending groove to the effect that the mounted brushes, when mounted in the brush module, extends at an angle relative to the radius of the grinding brush.

According to a further, alternative embodiment the body part is configured with one or more rows of brushes, and preferably two to four rows, that are shifted relative to each other. Hereby it is obtained that the brush module can be equipped with a plurality of brushes while simultaneously occupying a minimum of space on the brush module.

According to a further, alternative embodiment the grinding element is, at an edge, provided with a protruding bead which is complementary with the undercut groove. Hereby the grinding cloth can be mounted on the body part of the brush module by shifting, in a simple manner, the bead axially into the groove. At the same time this construction ensures that the grinding cloth cannot be swing out of the brush module when mounted on a grinding brush that rotates.

Other advantageous embodiments will appear from the dependent claims.

The invention will now be described in further detail with reference to the drawing; wherein:

Figures 1-2 show the grinding process during the treatment of an end face by an embodiment of the machine according to the invention;

Figure 3 is a sketch of a further preferred embodiment of a grinding brush according to the invention in the shape of a grinding cylinder; and

Figure 4 is a sectional view of the grinding brush shown in Figure 3;

Figure 5a shows a preferred embodiment of a brush module; and

Figure 5b shows a preferred embodiment of a grinding element module; and

Figure 5c shows the brush module of Figure 5a in a perspective view; and Figure 6 shows a holder means for grinding cloth in perspective view.

Figures 1-2 shows how a surprisingly effective grinding or polishing of the end face of a workpiece is obtained.

By 1 is designated a rotating grinding or polishing cylinder 1 to whose surface a major number of grinding elements and hold-back means for the grinding elements are provided. Figure 1 shows a single piece of grinding cloth 2 which is supported rearwardly relative to the direction of rotation by forwardly oriented hold-back means, preferably in the shape of brushes 3. In practice, a larger number of brushes are provided that are elastic and serve to keep the grinding cloth 2 in abutment on the end face 4 of a workpiece 5 as will be explained below.

The workpiece 5 is situated on a conveyor which is moved in the direction of the arrow, ie opposite the direction of rotation of the cylinder 1. However, the rate of conveyance is infinitesimally small compared to the rate of rotation of the cylinder. From Figure 1 to Figure 2, the cylinder has turned so much that the grinding layer 2 and the brushes 3 have advanced further and now they press on the end face 4 of the workpiece 5. Owing to the rotating movement, the grinding layer 2 is now pulled up along the end face simultaneously with the brushes 3 being bent still further rearwards until the grinding cloth loses contact with the end face, which takes place shortly after the position shown in Figure 3. Then the grinding continues as a consequence of the workpiece being conveyed as shown in Figure 4 and in accordance with known grinding principles, eg the teachings of WO 3004/103643.

Figure 3 shows a radial section through a preferred embodiment of a grinding cylinder 19 which is configured for being mounted transversely and horizontally relative to the direction of conveyance of the grinding machine. In the shown example, the grinding cylinder 19 of the figure is illustrated by one of the hub discs 20 that combine to form the grinding cylinder 19. The hub is seen inwards, from the side; it being understood that the grinding cylinder has a longitudinal direction that extends into the plane of the paper. The hub discs 20 are mounted against rotation on a shaft (not shown) to the effect that, when the hub discs 20 are mounted on the shaft, the hub 20 appears as a coherent unit which is, along the entire circular rim 22, provided with longitudinally extending grooves 21. From a centre of rotation indicated by reference numeral 23, a radius V extends towards the rim 22. The grooves 21 are undercut, ie they have the largest width at the bottom, closest to the centre, while being smaller at the outside of the hub 20. The undercut grooves 21 are intended for receiving a coupling part 17 on a brush module

10 or a grinding element module 11 , respectively, where these modules 10,

11 will preferably be mounted alternatingly between each other around the hub 20.

According to the invention, the brushes on the brush modules 10 are forwardly oriented.

It will be understood that, instead of consisting of hub discs, the hub could be in one piece with milled grooves for receiving the grinding and brush modules, 11 and 10, respectively.

In the following, reference is made to Figure 4, where a particular embodiment of the grinding cylinder comprising a brush module 10 and a grinding element module 11 will appear particularly clearly, see Figures 1-2. The Figure shows a section of the hub 20, on which both the brush module 10 and the grinding element module 11 are arranged around the circular rim of the brush, alternatingly in each their groove 21.

As will appear from Figure 5b, the grinding element module 11 comprises a body part 18 with a bottom face/top face 16 which is, in the longitudinal direction (ie into the plane of the paper), delimited by two side edges 14, 15. In connection with each of said side edges 14, 15, the body part 10 is provided with an undercut, longitudinally extending groove 12 for receiving a grinding element in the form of a holder means 30 with a grinding cloth 8 of a type like the one that appears from Figure 6, and extends from the holder means 30 to a free edge 8a. Alternatively, the grinding cloth 8 may be received directly in the groove 11. The grinding cloth 8 may have any kind of configuration, eg canvas or paper with a grinding face provided with grinding grains. The grinding cloth 6 comprises a grinding face 8b and is preferably sliced into thin strips as will appear from figure 8 in order to thereby provide a grinding cloth 8 which is particularly flexible for the grinding of essentially plane workpieces; it being understood that the strips make the grinding cloth particularly suitable for grinding recesses/profiles in the surface of the workpiece.

Correspondingly, the brush module 10, shown in figures 5a and 5c, is configured with a profile corresponding to the grinding element module. The brush module comprises a body part 18 with a bottom face/top face 16 which, in the longitudinal direction (ie into the plane of the paper), is delimited by two side edges 14. 15. From the bottom face, the bristles extend radially forwards relative to the direction of rotation on the rotating brush, towards a free edge 13a.

Opposite the body part 18, both the brush module 10 and the grinding element module 11 are provided with a coupling part 17 that extends from the body part 18 in a direction opposite bristles 13/grinding cloth 8, and serves to secure the modules 10, 11 , the coupling part 17 being configured to fit into an axially configured keyway 21 on a hub 20 for a horizontally configured grinding cylinder (not shown). In principle, reference number 100 shows the same as 5 in Figure 1 , and an end face 101 corresponds to the end face 4 of Figure 1. By combination of the rotation and the movement of the workpiece 100 in the direction of conveyance of the apparatus, the free edge 8a on the grinding cloth establishes contact with the end face 101 of the workpiece as explained in the context of Figures 1 and 2, following which the grinding cloth (the grinding means) 8 is taken across the edge 103, following which the upper side 102 of the workpiece is grinded in a usual manner.

In figures 5a and 5c, reference numeral 7 shows one of several bores that are configured side by side in the longitudinal direction of the brush module 10 for receiving the bristles 13. According to the invention, these bristles 13 extend radially forwards relative to the direction of rotation of the rotating brush; it being understood that, hereby, the bristles are angled forwards in a direction towards the longitudinal groove 12 with the grinding element.

Bristles 13 and the grinding element 8 may, as described above, be mounted in separate modules, but they may also, in a preferred embodiment of the invention, be mounted in the same module as the grinding element. Alternatively the brush module may comprise a longitudinally extending groove (not shown) which extends centrally on the upper side of the brush module and which extends into the brush module and is configured for receiving the plurality of brushes 13. At an edge, these brushes will be mounted with a bead which is complementary to the longitudinally extending groove, to the effect that the grinding element 30 is axially displaceable in the longitudinal direction of the brush module.

It applies to all embodiments that the bristles 13 are preferably angled at an angle 'α' of between 10° and 60°, and more preferably at an angle of between 25° and 45° relative to an axis 'A' that extends through the brush module 1 and which is essentially in parallel with radius of the rotating brush. Preferably, bristles 13 extend from the middle of the bottom face 16 and, during grinding, they serve to provide an abutment pressure on the rear side of the grinding cloth and will preferably be slightly shorter than the grinding cloth as such.

In Figure 6, the holder means 30 for the grinding cloth is shown. The holder means 30 is configured with a protruding bead 31 which is configured to cooperate with the groove 12 in the body portion 10 of the brush module; it being understood that the holder means 30 has a longitudinal expanse corresponding to the longitudinally extending groove 12. Opposite the bead 31 , the holder means is configured with two flaps 32, 33 that extend at an angle relative to each other. Between the two flaps 32, 33 the grinding cloth 8 is arranged, following which the flaps 32, 33 are pressed towards each other and thus tightly clamp the grinding cloth 8.

The invention was described with reference to a preferred embodiment, but it may be varied to the effect that the body part of the brush module can be configured to engage directly with the undercut, longitudinally extending grooves in a grinding drum or cylinder, respectively. Moreover, the grinding cloth may be secured directly on the brush module, eg by use of clips or gluing directly onto the sides of the body part.

Claims

C l a i m s

1. A machine for surface treatment, such as grinding or polishing workpieces and comprising a rotating cylinder which has a number of treatment modules that extend outwards and away from the cylinder surface, and comprises at least one piece of grinding cloth, characterised in that hold-back means are provided that comprise elastic lamellae or brushes that are embedded in proximity of the cylinder face, from where they extend to a respective grinding cloth in directions which - seen in the direction of rotation - are situated in front of an axial plane through the embedding of the hold-back means at the cylinder surface.

2. A machine according to claim 1 , characterised in that both the grinding cloth and the hold-back means extend outwards and forwards relative to the direction of rotation.

3. A machine according to claim 1 or 2, characterised in that the grinding cloth extends a small distance radially further than the hold-back means.

4. A machine according to claims 1-3, characterised in that the hold-back means comprise one or more pieces of grinding cloth.

5. A machine according to claims 1-4, characterised in that the hold-back means comprise brushes.

6. A machine according to claim 5, characterised in that nylon brushes are provided that have embedded grinding grains.

7. A machine according to claims 1-6, characterised in that it comprises a hub which, in its cylindrical surface, has longitudinally extending grooves for receiving a brush module (10) comprising - an elongate body part (18), wherein the cross sectional shape of the body part (18) comprises an upper side (16) and a number of sides 14, 15;

- wherein the bristles (13) extend from the upper side (16) of the body part (18); and

- a coupling part (17) which is configured for interconnection with complementary coupling means on a hub in the rotating brush, and wherein the coupling part (17) protrudes from the body part (10) in a direction opposite the bristles (13).

8. A machine according to claims 1-6, characterised in that it comprises a hub which is composed of a number of separate hub discs (20) that are mounted against rotation on a shaft of rotation (22) and are configured to cooperate with a brush module (10), comprising - an elongate body part (18) wherein the cross sectional shape of the body part (18) comprises an upper side (16) and a number of sides 14, 15;

- wherein the bristles (13) protrude from the upper side (16) of the body part (18), and - a coupling part (17) which is configured for interconnection with complementary coupling means on a hub in the rotating brush, and wherein the coupling part (17) projects from the body part (10) in a direction opposite the bristles (13).

9. A machine according to claim 7 or 8, characterised in that the bristles (13) extend at an angle of between 10° and 60° relative to the radius of the cylinder.

10. A machine according to any one of the preceding claims, characterised in the bristles (13) extend at an angle of between 25° and 45° relative to the radius of the cylinder.

11. A machine according to any one of claims 7-10, characterised in that a plurality of radially protruding grinding elements (8) are configured around the cylinder face, wherein the cylinder (19) and the grinding element (8) are provided with complementary, mechanical coupling means, to the effect that the grinding element (8) is mounted releasably on the cylinder.

12. A machine according to claim 11 , characterised in that it further comprises a grinding module (11 ) with - an elongate body part (18), wherein the cross-sectional shape of the body part (18) comprises an upper side (16) and a number of sides 14, 15;

- a plurality of bristles (13) that protrude from the upper side (16) of the body part (18), and - a coupling part (17) that is configured for interconnection with complementary coupling means on the hub of the rotating brush; and wherein the coupling part (17) extends from the body part (18) in a direction opposite the bristles (13).

13. A machine according to claim 12, characterised in that the grinding element module (11) comprises a longitudinally extending groove (12) that extends from the upper side of the brush module, and extends into the brush module and is configured for receiving a grinding element (8) that projects from the body part (18), wherein the body part (18) and the grinding element (8) are provided with complementary, mechanical interconnection means to the effect that the grinding element (8) is releasably mounted on the body part (18).

14. A machine according to claim 11 , characterised in that the longitudinally extending groove (12) is configured in proximity of one of the sides (14, 15) of the grinding element module (11 ).

15. A machine according to any one of claims 7-14, characterised in that the brush module (10) and the grinding element module (11) is configured alternatingly between each other relative to the direction of rotation of the cylinder.

16. A machine according to any one of claims 7-15, characterise! in that the body part (18) on the brush module (10) is configured with one or more rows of brushes (13), and preferably 2-4 rows that are shifted relative to each other.

17. A machine according to any one of claims 7-16, characterised in that the brush module (10) and the grinding element module (11) is manufactured either from a moulded/extruded thermoplastic material or a metal alloy.

18. A machine according to any one of claims 7-17, characterised in that the grinding element (8) is, at an edge, provided with a protruding bead (31 ) which is complementary with the undercut groove (12).

19. A machine according to any one of claims 7-18, characterised in that the grinding element (8) comprises a grinding cloth.

20. A brush module for a machine of the kind featured in claims 1-19, characterised in that the module (10) has a body part (18) which coheres with a coupling part (17) which is configured for being received in the machine in a predetermined position; and that bristles (13) extend from the body part (18) in such direction that the bristles (13) extend radially outwards and forwards relative to the direction of rotation, when the brush module (10) is arranged in said position.