EP1477275A1

EP1477275A1 - Abrading machine with abrading discs, which are moved in a reciprocatory movement transverse to the item

Info

Publication number: EP1477275A1
Application number: EP04004127A
Authority: EP
Inventors: Poul Lundum
Original assignee: Slipcon Holding International ApS
Current assignee: Slipcon Holding International ApS
Priority date: 2003-05-12
Filing date: 2004-02-24
Publication date: 2004-11-17
Anticipated expiration: 2024-02-24
Also published as: EP1477275B1; DE602004015666D1; CN1784291A; ES2312870T3; DK200300722A; ATE404323T1; PT1477275E; DK178219B1

Abstract

An abrading machine is disclosed for abrasion of substantially plane items by use of rotating abrading discs (5,5'), which are moved simultaneously forwards and backwards transverse to the item and which preferably has downward extending abrasive lamellae.

The machine also preferably comprises one, typically two, opposite rotating abrading cylinders (7,7') fitted with elongated abrasive elements radially mounted on the abrading cylinder and has abrasive lamellae extending outwards from the cylinder.

By moving the abrading discs in a reciprocatory movement (4) transverse to the direction of feed (A) of the items it is achieved that traces etc. from the different abrasive properties of the abrading discs are eliminated as well as all parts of milled out areas etc. are evenly abraded, particularly if the abrading device is designed for using abrading discs with abrasive means comprising abrasive lamellae made of abrasive cloth and which extend downwards from the face of the abrading disc.

Description

The invention relates to an abrading machine for abrasion of substantially plane items using rotating abrading discs, which simultaneously reciprocate, i.e. move forwards and backwards, transverse to the item and preferably has downwardly extending abrasive lamellae.
It is preferred that the machine also comprises one, typically two, counter rotating abrading cylinders equipped with elongated abrasive elements, which are radially mounted on the abrading cylinder with the abrasive lamellae extending radially from the cylinder.

BACKGROUND OF THE INVENTION

For abrasion of items with a plane surface an abrasive belt often used, which is mounted on a belt sander. However, this abrading method is only suitable for abrasion of completely plane surfaces, as carvings in or other shapings of the surface will be "smoothed out" and the lowered surface will not be abraded by the abrasive belt. At the same time, the exactness of the abrasion is thereby not satisfactory in relation to many abrading tasks. This means that this abrading method is unsuitable for many abrading tasks within, e.g., the furniture industry where a gentle but at the same time complete abrasion is required. Similar problems with performing a complete deburring and abrasive or polishing surface treatment in connection with cut-out, milled out and laser-cut items are known from the metal industry as well as in production and surface processing of so-called "solid surface" items.
Within, among others, the production of furniture many different abrasion tasks depend on the size and shape of the item. Within the last decades, a considerable automation of the production of wood products has taken place within, among others, the furniture industry, which also makes new demands on the abrading tools. In, among others, WO 01/76824 and US-A-6,267,660 a rotating abrading tool is described in the form of a roll with abrasive elements, a so-called abrading cylinder, which is suitable for abrasion of profiled or plane items. Here, the plane item is conveyed through the abrading device on a conveyor belt, a trolley or the like in a continuous movement. The roll is brought to rotate about its longitudinal axis and the rotating abrading tool is brought into contact with the surface, whereby a gentle abrasion may take place. This abrasive method is gentle due to a low abrasive pressure but it may be a slow abrasive process in relation to abrasive tasks on a general plane face having shapings, e.g., a door. In this case, it is necessary to move the abrading tool in a complicated movement around along the shapings to ensure a complete abrasion of these. In this connection it is also of great importance which rotational direction the abrading tool has in relation to the profile curves. The result is that the conduction of the abrasive task becomes slow and at the same time may be difficult to fully automate which also makes the tool inefficient seen from a production cost view.
Thus, to achieve an efficient working procedure at abrasion of items with shapings or other carvings in a substantially plane surface, it may be necessary to apply belt abrasion for the plane faces and a rotating abrading tool for the shaping areas, where the abrading tool is moved about along the shapings.
Thus, it is a purpose of the present invention to achieve an abrading device which complies with the disadvantages of the known techniques as described above by enabling an efficient, simultaneous and uniform abrasion or processing of an item's surface.
By the present invention an abrading device for abrasion of substantially plane items is provided, said device comprising means for conveyance of the items in a direction of feed, suspension means for suspension of a plurality of abrading discs for abrasion of a side of the items, means for driving rotation of the abrading discs around axes being substantially perpendicular on the side of the items, and means for driving the abrading discs in a reciprocatory movement transverse to the direction of feed of the items. By moving the abrading discs in an oscillatory or reciprocatory movement transverse to the direction of feed of the items it is achieved that traces etc. from the different abrasive properties of the abrading discs across the diameter of the disc are eliminated as well as all parts of milled out areas etc. are abraded evenly, especially if the preferred abrading device is arranged to apply abrading discs with abrasive means which comprise abrasive lamellae of an abrasive sheet, such as abrasive cloth where the surface of which has abrasive properties and which extends from the face of the abrading disc. Such abrading discs are, e.g., described in US-A-4,493,170, in DE-A-24 11 749 and in EP-A-0 922 535.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to an abrading device for abrasion of substantially plane items, said device comprising
means for conveyance of the items in a direction of feed,
suspension means for suspension of a plurality of abrading discs having abrasive means for
abrasion of a side of the items,
means for driving rotation of the abrading discs around axes, which are substantially perpendicular to the side of the items, and
means for driving the abrading discs in a reciprocatory movement transverse to the direction of feed of the items.
The suspension means for suspension of the abrading discs is preferably made as one single structure so that the reciprocatory movement of all the abrading discs can be driven by the same drive means. This or these means may typically be an electrical or hydraulic motor, which drives rotation of an axis with an eccentric attachment to the suspension means but may, e.g., instead consist of an elastic suspension of the suspension means and a solenoid which is turned on and off at a given frequency by a relay, thus performing regularly changing forces between the suspension means and a stationary part of the abrading device.
This reciprocatory movement transverse to the direction of feed of the items is preferably a substantially strictly transverse movement but may also, e.g., comprise a circular or elliptical shaped movement of the abrading discs as long as the movement pattern includes said reciprocatory movement. The reciprocatory movement of the abrading discs has in one embodiment preferably a length of stroke of 40-100%, preferably 60-85%, of the diameter of the discs to eliminate the tendency to groove formation. By length of stroke is understood the distance between the two extreme positions in transverse direction of the centre axis of an abrading disc.
It is preferred that the suspension means are arranged for suspension of abrading discs with abrasive means, which extend from the face of the abrading disc in as much as such abrading discs, as, e.g., known from US-A-4,493,170, from DE-A-24 11 749 and from EP-A-0 922 535, are particularly suitable for abrasion of lowerings in the surface such as milled out areas or perforations. According to the invention, the device may, however, also comprise abrading discs with plane abrasive means such as a yielding disc mounted with an abrasive ring of abrasive paper or abrasive cloth, which may vary in hardness depending on the task.
The abrading device may advantageously comprise a plurality of abrading discs with undercut grooves for reception and fixing of profile rails which form a part of elongated abrasive elements comprising abrasive means, said grooves preferably extend in a mainly radial direction on the face of the abrading disc. Thereby, the abrading discs can receive elongated abrasive elements which consist of abrasive means in the form of lamellae of abrasive cloth of which the front side has abrasive properties and the back side is supported by support elements being elastic in the tangential direction of the disc, so that the front side of the abrasive cloth is pressed into abutment with a relatively high abrasive pressure with the surface to be abraded and thus the abrasion can take place at low feed velocity of the abrasive element, i.e. low rotational speed of the abrading disc, in order to prevent strokes at the point between faces and profiles and partly in order to keep the front side of the abrasive cloth in continuous contact with the surface of the item to be abraded, which results in a uniform and complete abrasion. The support elements are preferably brushes, e.g., natural brushes, which extend from the face of the disc in a shorter distance than the abrasive means so that the support elements are not normally in contact with the item. The abrasive means and support elements are secured in a profile rail with a cross section corresponding to the cross section of the grooves such that the abrasive elements are easily pushed into and retained by the grooves and also easily removed from them whereby a replacement of worn abrasive elements or a conversion of the device to another kind of processing with other abrasive elements is easily performed. Suitable kinds of abrasive elements are described in, e.g., WO-A-01/76824.
Furthermore, holding elements may be arranged between the abrasive elements in order to limit the deflection of the abrasive means. The effect of the holding elements is that the abrasive means at a certain deflection thereof become engaged with the holding element at the back, which results in an increased stiffness of the abrasive means and thereby requires greater force for further deflection. The holding elements preferably comprise a holding brush having a shorter length than the abrasive elements and which is mounted in a profile rail, which is received in a corresponding undercut groove on the face of the abrading disc.
The means for driving the rotation of the abrading discs is normally arranged in such a way that all abrading discs are rotated the same way. However, it is also an option according to the present invention that adjacent abrading discs are rotated in the opposite direction which in combination with the reciprocatory movement of the abrading discs results in a more uniform abrasion of all parts of the item surface.
The plurality of abrading discs may preferably be arranged so that they are aligned transversely to the direction of feed of the items. In a further preferred embodiment, the plurality of abrading discs are arranged in two consecutive rows transversely to the direction of feed of the items, wherein the discs in one row are staggered with respect to the discs in the other row. In the latter arrangement, the length of stroke may be reduced and is preferably a magnitude of 20-50%, preferably 30-43%, of the diameter of the discs.
The abrading device, according to the invention, may further comprise at least one abrading cylinder, preferably two opposite rotating abrading cylinder, which are arranged to abrade a side of the item, and which preferably comprises abrasive means extending substantially radially from an elongated core, said abrading cylinder(s) extending transversely to the direction of feed and is/are driven to rotate about their longitudinal axes. Preferably, the at least one abrading cylinder is arranged after said side has been abraded by the abrading discs but may alternatively be arranged before, so that the items meet the cylinder prior to the abrading discs. An abrasion with rotating abrading discs can be relatively aggressive as there will be some transversal abrasion of the items and the device is typically designed for a relatively high abrasion pressure and low rotational speeds of the abrading disc in order not to deform possible shapings in the work piece. Thus, some "wild" abrasive scratches will occur due to the rotation but these will be removed by the one, two or more abrading cylinder, which will, typically, be equipped with a rougher grit size than the abrading discs. Alternatively, the machine may be constructed with an extra similar module with a plurality of abrading discs in order to leave out the abrading cylinders.

SHORT DESCRIPTION OF THE DRAWING

Preferred embodiments of an abrading device according to the invention is described in the following with reference to the enclosed drawing in which
Fig. 1 illustrates the abrading device seen from above with some parts left out so that the abrasive parts are visible,
Fig. 2 illustrates a part of the abrasive device seen from the feed end in a perpendicular section through the abrading discs; in which the abrading discs, their slide and the drive are illustrated,
Fig. 3 illustrates the abrading device seen from the side in a perpendicular section,
Fig. 4 illustrates an abrading disc, the slide of the abrading discs and their suspension and drive seen from the side in a partly section, and
Fig. 5 illustrates a second embodiment of the present invention.

DETAILED DESCRIPTION OF AN ABRADING DEVICE ACCORDING TO THE INVENTION

In the following, a preferred embodiment of an abrading device according to the invention is described as an example and illustration of the invention. The example does not serve to limit the invention and from the description and the claims, the skilled person will be able to embody a number of alternative devices, which will all be within the scope of the invention.
The abrading device 1 comprises a conveyor belt 2 driven continuously or stepwise by a motor 3 and is used to convey substantially plane items through the abrading device 1 from a feed end 4 in a direction of feed indicated by the arrow A on Fig. 1. Hereafter, the upper side of the item contacts with six abrading discs 5 arranged in a row which is transversal in relation to the direction of feed of the item and where the abrading discs 5 are rotated clockwise and counter-clockwise alternately such that two adjacent abrading discs 5 are rotated in separate directions as indicated by the arrows B-G on Fig. 1. Alternatively, the drive of the abrading discs 5 may also be arranged such that all the abrading discs 5 rotate in the same direction. The abrading discs 5 are mounted on a slide 10 which during operation is moved in a reciprocatory movement as indicated by the arrow H on Fig. 1, where the movement has a length of stroke so that the extreme positions of each of the abrading discs 5 centre positions in the reciprocatory movement are situated with a mutual distance of 75% of the diameter of the abrading discs 5. Each abrading disc 5 consists of a disc 6 which, on the bottom side facing down towards the item, has a plurality of undercut, radially running grooves (not shown) in which abrasive elements (not shown) are received comprising a profile rail which retains a number of abrasive lamellae of which the front side has abrasive properties and of which the back side is supported by a number of support brushes. The abrasive lamellae extend downwards from the disc towards the item substantially perpendicular to the rotation plane of the disc. A suitable type of such abrasive lamellae consisting of profile rail, abrasive lamellae and brushes is, e.g., described in WO-A-01/76824. The abrasive elements are orientated in such a way that the front side of the abrasive elements with the abrasive properties are at the front in the rotational direction. The abrasive elements are secured on the disc by the interaction between the profile rail and the undercut grooves having a dovetailed cross section of the opening, and by a ring, which extends around the periphery of the disc and closes the open end of the rails at the periphery of the disc. This ring is removable after which the abrasive elements can be pushed out of the grooves and new abrasive elements can be pushed in. After having passed the abrading discs 5 the items are transported further on the conveyor belt 2 under two opposite rotating abrading cylinders 7, 7' which remove possible scratches in the surface of the items and give the surface the final finish. The abrading cylinders 7, 7' are driven by associated motors 8, 8'. Suitable abrading cylinders are, e.g., described in WO-A-01/76824. Thereafter, the conveyor belt 2 conveys the items out of the abrading device at its exit end 9.
As shown in Figs. 2-4 the abrading discs 5 are mounted on a common slide 10 which is movable in transverse direction in relation to the direction of feed of the items in as much as the slide 10 comprises two rails 11 that run in three sets of wheels 12 which are securely mounted on a transverse beam 13 which is secured to the frame 14 of the abrading device 1. Each abrading disc 5 is mounted on a vertical axle 15, which is embedded in the slide 10 with bearings 16 such that it turns freely about its vertical axis with minimal friction. The axle 15 extends through the slide 10 and has at its upper end a pulley 16 to cooperate with a v-belt 17 for driving the rotation of the abrading discs 5. All abrading discs 5 are driven by a motor 18 mounted on the slide 10, which has a pulley 20 mounted on its driving axle 19. On Fig. 3 and 4 the extension 21 of the abrasive lamellae in vertical direction is indicated.
The reciprocatory movement of the slide 10 transverse to the direction of feed of the items is driven by a separate motor 22 via an eccentric mechanism 23.
The embodiment shown in Fig. 5, the abrading discs 5, 5' are arranged in two successive rows transversely to the direction of feed A of the items, and the discs 5 in the first row are staggered with respect to the discs 5' in the second row. All the discs 5, 5' are arranged on a common slide 10 which, due to the staggered arrangement, during operation is moved in a reciprocatory movement as indicated by the arrow H on Fig. 1, with a length of stroke of about half of the magnitude of the embodiment shown in Fig. 1, i.e. the extreme positions of each of the abrading discs 5, 5' centre positions in the reciprocatory movement are situated with a mutual distance of about 35-40% of the diameter of the abrading discs 5, 5'.

Claims

An abrading device for abrasion of substantially plane items, said device comprising
means (2) for conveyance of the items in a direction of feed (A),
suspension means (10) for suspension of a plurality of abrading discs (5, 5') having abrasive means for abrasion of a side of the items,
means (18) for driving rotation of the abrading discs around axes, which are substantially perpendicular to the side of the items, and
means (22, 23) for driving the abrading discs (5, 5') in a reciprocatory movement transverse to the direction of feed (A) of the items.
An abrading device according to claim 1, where the abrasive means extends outwards from the face of the abrading discs (5, 5').
An abrading device according to claim 2, wherein the plurality of abrading discs (5, 5') have undercut grooves for reception and fixing of profile rails which form a part of elongated abrasive elements comprising abrasive means, said grooves preferably extend in a mainly radial direction on the face of the abrading disc.
An abrading device according to any of the claims 1-3, where the abrading discs (5, 5') are arranged aligned transversely to the direction of feed of the items.
An abrading device according to any of the claims 1-4 in which the reciprocatory movement of the abrading discs (5, 5') has a length of stroke of 40-100%, preferably 60-85%, of the diameter of the discs.
An abrading device according to any of the preceding claims, wherein the abrading discs (5, 5') are arranged aligned in two successive rows transversely to the direction of feed of the items, the discs (5) in one row being staggered with respect to the discs (5') in the other row.
An abrading device according to claim 6, in which the reciprocatory movement of the abrading discs (5, 5') has a length of stroke of 20-50%, preferably 30-43%, of the diameter of the discs.
An abrading device according to any of the claims 1-7 comprising a plurality of abrading discs (5, 5') with abrasive means, which comprise abrasive lamellae of an abrasive sheet, such as abrasive cloth, of which the front side has abrasive properties and which extend from the face of the abrading disc.
An abrading device according to claim 8 where the abrasive means comprise an elastic support element, preferably support brushes, which support the backside of the abrasive lamellae, said support element substantially having almost the same length as the lamellae.
An abrading device according to claim 8 or 9, where the abrasive means are arranged in elongated abrasive elements extending primarily in radial direction on the faces of the abrading discs.
An abrading device according to claim 10 where the abrasive elements comprise profile rails in which the abrasive means are attached and which are received in undercut grooves in the abrading discs.
An abrading device according to claim 10 or 11 in which holding elements are arranged between the abrasive elements.
An abrading device according to claim 12, where each of the holding elements comprises a holding brush that displays a shorter length than the abrasive elements and which is mounted in a profile rail arranged in a similar undercut groove.
An abrading device according to any of the preceding claims further comprising at least one abrading cylinder (7, 7'), which is arranged to abrade a side of the item and which preferably comprises abrasive means extending substantially radially from an elongated core, said abrading cylinder (7, 7') extend transversely to the direction of feed (A) and is driven to rotate about its longitudinal axis.
An abrading device according to claim 14, wherein the at least one abrading cylinder (7, 7') is arranged after the abrading discs (5, 5') in the direction of feed (A) of the items.