EP0625407B1 - Grinding machine - Google Patents

Abstract

The grinding head (6) is movable relatively to the surface of the workpiece. The grinding head movement is by means of motor drive and at least one sensor detects the edge (15) of the workpiece (11) located in the travel path (14,14') of the grinding head. A control limits the travel path correspondingly to the detected edge (15) and controls the movement of the grinding head. The control after acting on the grinding head moves it on another travel path (14',17') over the workpiece, which is parallel to the first. The grinding head is pivotably fitted on an X-Y travel device around a rotary axis vertical to the workpiece accommodation plane.

Description

The invention relates to a grinding machine with at least a grinding head with a sanding belt, which is by means of a Pressure bar on a workpiece moved relative to the grinding head is pressed, the grinding head over the surface of the workpiece is designed to be movable.

Such grinding machines are in numerous embodiments known. With these belt grinding machines, the workpiece placed on a conveyor belt and under the driven and abrasive belt pressed against the surface of the workpiece promoted through. To achieve an improved grinding result to achieve multiple grinding directions, it is known to Perform cross sanding by the surface of the workpiece ground in two mutually perpendicular directions becomes. Grinding machines that have such a cross grinding in in one pass are necessarily large plants, that require a significant investment.

To create a cross cut, it is also possible to do that Workpiece through a smaller sanding belt machine with only one Transport sanding belt through and after passing through the workpiece again in a position rotated by 90 ° to run through the same grinder. This Working method requires a not inconsiderable operating effort, because larger workpieces by two people at the outlet of the Machine detected, transported to the inlet again and in the rotated Form must be pushed back into the machine.

From JP-A-59-115155 a grinding machine is known which is specially designed for sanding wooden frames. Of the Wooden frame is positioned on a conveyor belt on which it is movable in the conveying direction. There is a on a portal The grinding head is mounted so that it can move across the conveying direction. For Grinding the frame becomes the grinding head at an exit corner positioned and towards the respective rectilinear Frame section moves, either through the Movement of the grinding head on the portal or by an appropriate one Advance of the workpiece. The grinding head is formed by an all-round sanding belt with a pressure shoe, and becomes perpendicular to that for grinding one previously ground frame part standing frame part by 90 ° turned. The execution of several grinding directions on one Frame part itself is not provided.

The problem in the prior art is that either a considerable mechanical or a considerable operating effort is required to get a high quality surface finish to achieve. The problem underlying the invention consists of specifying a grinding machine which enables improvements to be made to the problem described.

According to the invention, one is to solve the problem posed Grinding machine of the type mentioned in the introduction, that at least one sensor one in the travel of Abrasive head lying edge of the workpiece detects that a controller determines the travel distance according to the detected one Limited edge and reversed the movement of the grinding head, that the pressure beam from a variety of pressure shoe members exists, which are individually switchable into an active position and that the circuit of the pressure shoe members in the operative position can be controlled by the at least one sensor.

In departure from the previous types of grinding machine, where the grinding head is stationary with the grinding belt is mounted and the workpiece under the grinding head is transported, sees the grinding machine according to the invention a moving grinding head over the surface of the Workpiece is movable so that the workpiece even when stationary can stay. The movement of the grinding head over the The surface of the workpiece is automatically controlled. For this purpose, the grinding head is moved from a starting position in one Move the first travel path over the surface of the workpiece. A sensor of the grinding head detects an edge of the Workpiece that lies in the travel of the grinding head and causes a reversal of the movement of the Grinding head, whereupon this preferably automatically another path is guided over the workpiece. The Control is set so that the entire surface of the workpiece is grasped by the grinding head, ie ground becomes. The pressure beam of the grinding machine according to the invention consists in itself, for example, of EP 0 155 380 B1 known manner from a large number of pressure shoe members, which can be switched individually into an active position, preferably the switching of the pressure shoe members into the operative position can be controlled by the at least one sensor. On this way it is possible to get even machining too to be achieved if the grinding head has a longitudinal direction Edge lying in the direction of travel.

The type of travel depends on the shape and possibly the grain direction the wooden surface.

It is particularly useful for rectangular workpieces be when the grinding head to switch to one to the ended Travel parallel travel is offset so that ground the surface of the workpiece in parallel grinding tracks becomes. The execution of a cross cut is then easily possible by rotating the grinding head by 90 ° and then perpendicular to the previous travel paths is driven over the workpiece in parallel paths. The The grinding head can expediently be rotated by that the grinding head on an X-Y traversing device an axis of rotation perpendicular to the workpiece receiving plane is pivotally attached.

The sensor recognizing the edges of the workpiece can be by parallel to the pressure bar on the leading or trailing edge arranged sensor strips of the grinding head. These can take into account the travel speed of the grinding head the end of the workpiece in the direction of travel recognize and make the reversal, the arrangement the sensor strips on the leading and trailing edge allows that move the grinding head forwards and backwards over the workpiece can.

But it is also possible to change the edges of the workpiece in another Way to determine. So it can offer itself on the Attaching a camera to the grinding head, the contour of the workpiece, seen at least in the direction of travel, recognizes. It is but also conceivable that a camera the complete contour of a Workpiece and controls the movement of the Grinding head for the complete machining of the workpiece determined.

In a further advantageous embodiment, the Height-adjustable grinding head attached. As a result, a Adaptation to different workpiece thicknesses. If the Grinding head equipped with at least one distance sensor is, it is possible that the grinding head changes follows the distance, for example also with curved ones Workpieces allow a perfect grinding result.

It can be useful if the pressure bar is vertical a spherical to the direction of movement of the grinding belt Has curvature because of the resulting linear Uniform grinding processing even with bulges is possible.

Although the workpiece in the grinding machine according to the invention can also be moved in principle, it is preferred that the workpiece receiving plane through a stationary workpiece table is formed, which is preferably a holding device for the stationary mounting of the workpiece in the workpiece receiving plane having.

Figur 1 -

eine Draufsicht auf einen Werkstücktisch mit einem verfahrbaren Portal, an dem ein Schleifkopf schwenkbar angebracht ist,

Figur 2 -

eine Ansicht auf eine Längsseite der Anordnung gemäß Figur 1,

Figur 3 -

eine Ansicht auf eine Stirnseite der Anordnung gemäß Figur 1,

Figur 4 -

eine Draufsicht auf die Vorrichtung gemäß Figur 1 mit eingezeichneten Verfahrwegen für die Durchführung eines Kreuzschliffs,

Figur 5 -

einen vertikalen Schnitt durch ein erstes Ausführungsbeispiel eines Schleifkopfes,

Figur 6 -

einen horizontalen Schnitt durch den Schleifkopf gemäß Figur 5,

Figur 7 -

einen vertikalen Schnitt durch eine zweite Ausführungsform eines Schleifkopfes, der über eine gewölbte Oberfläche bewegt wird,

Figur 8 -

einen horizontalen Schnitt durch einen Schleifkopf und seine Befestigung an dem verfahrbaren Portal.

The invention is explained in more detail below with reference to exemplary embodiments shown in the drawing. Show it:

Figure 1 -

a plan view of a workpiece table with a movable portal on which a grinding head is pivotally attached,

Figure 2 -

2 shows a view of a long side of the arrangement according to FIG. 1,

Figure 3 -

2 shows a view of an end face of the arrangement according to FIG. 1,

Figure 4 -

2 shows a top view of the device according to FIG. 1 with traversed travel paths for carrying out a cross grinding,

Figure 5 -

a vertical section through a first embodiment of a grinding head,

Figure 6 -

4 shows a horizontal section through the grinding head according to FIG. 5,

Figure 7 -

a vertical section through a second embodiment of a grinding head, which is moved over a curved surface,

Figure 8 -

a horizontal section through a grinding head and its attachment to the movable portal.

Figure 1 shows a rectangular workpiece table 1, the long one Edges of guide rails 2 are limited. On the guide rails 2 is a portal 3 in the longitudinal direction of the table movable. On the portal 3 is a support arm 4 in the longitudinal direction of the portal 3, that is perpendicular to the longitudinal axis 5 of the workpiece table 1, movably mounted. On the support arm 4 is a Grinding head 6 attached. The movable portal 3 and the on the bracket 3 movable arm 4 form a conventional X-Y traversing device 3, 4. The grinding head 6 is on the support arm 4 around a swivel joint 7 perpendicular to the X-Y plane pivotable. Figure 1 shows a in the solid lines first position of the grinding head 6 and in dashed lines a second position of the grinding head pivoted through 90 ° 6. FIG. 1 shows 6 in the representations of the grinding head schematically indicated the longitudinal extent of a pressure bar 8.

FIGS. 2 and 3 show that the workpiece table 1 consists of a conventional base 9, on which there is a Workpiece receiving level 10 is located to receive a Workpiece 11 is used.

In Figures 2 and 3 there is a 6 within the grinding head usual guidance of an abrasive belt 12 around three rollers 13 indicated. Figure 3 shows the grinding head 6 again in two to each other positions pivoted through 90 °.

FIG. 4 illustrates the machining of a workpiece 11 a starting position of the grinding head 6, in which this located at an end edge of the workpiece 11 so that the portal 3 moved into an end position with respect to the workpiece 11 by moving the support arm 4 along the portal 3 perpendicular to the longitudinal axis 5 of the workpiece table 1 on a move first travel path 14. After running over one in the Travel 14 lying, detected edge 15 of the workpiece 11, the first travel path 14 is ended and the grinding head 6 reversed by lateral displacement so that it is on a to the first travel path 14 parallel travel path 14 'in the reverse direction is moved over the workpiece 11. To this A subsequent grinding on each other becomes like this parallel grinding tracks in the transverse direction of the workpiece 11 performed until the surface is completely sanded is. The grinding head 6 is then turned 90 ° around the axis of rotation 7 pivots, as is the case by the web 16 in FIG. 4 is indicated. Then the surface is moved by moving the Grinding head 6 perpendicular to parallel travel paths 17, 17 ' to the first traverse paths 14, 14 ', so that a complete cross-cut has been produced.

Figures 5 and 6 illustrate the structure of a grinding head 6 in a first embodiment. In the usual way a grinding belt over three pulleys 13, two Deflection rollers 13 arranged parallel to the workpiece receiving plane 10 are and take up the pressure bar 8 between them.

As shown in Figure 6, the pressure bar consists of a A plurality of link pressure shoes 18, individually, for example by electromagnets or by compressed air, in the operative position are controllable. The movement of the grinding head 6 over the workpiece takes place perpendicular to the longitudinal axis 8 'in one Travel axis 19. On a leading edge and a trailing edge Edge with respect to the direction of travel 19 is the Grinding head 6 each provided with a sensor strip 20, 21, on which a plurality of sensors 22 are arranged side by side are. The sensors 22 can be capacitive, for example Sensors that are capable of a wooden workpiece 11 in capacitively detect a distance of a few millimeters.

The sensors 22 are expediently individual individual pressure shoes 18 assigned. Detect the sensors 22 that the Grinding head 6 over a lying in the direction of movement 19 Long edge of the workpiece 11 moves, they are no longer on the workpiece 11 hitting link pressure shoes 18 in an ineffective Position, as is known per se, to to avoid grinding the workpiece edges.

Figure 7 shows an embodiment of the grinding head 6, at whose effective tool surface 23 in the direction of movement 19 is domed and therefore on a width of the pressure beam 8 narrower line on the workpiece 11 ' takes effect. The workpiece 11 'is shown arched in FIG. 7. The grinding head 6 follows this curvature in that it is attached to a height-adjustable support arm 4 ', as indicated in Figure 8. For this, the sensors 22 of the leading sensor strip 21 also as distance sensors used or a separate distance sensor is installed, the height adjustment of the grinding head 6 and his Carrier arms 4 'on the portal 3 controls so that the grinding head 6th the curvature contour of the workpiece 11 'can follow. Of course the corresponding sensors 22 are also suitable automatic adjustment to workpieces of different thicknesses bring about.

Based on the drawing is a cross cut for a rectangular Workpiece has been represented. Of course it is possible to provide other trajectories if this is due to the grain directions of the wood surface or another Shape of the workpiece (e.g. round table top) required or seems appropriate. Naturally, the length of the Pressure bar 8 can be varied and possibly on a single Reduce pressure shoe, which is also suitably shaped can be.

Claims (12)

1. Grinding machine having at least one grinding attachment (6) with a grinding belt (12), which is pressed by means of a pressure bar (8) onto a workpiece (11, 11') displaced relative to the grinding attachment (6), the grinding attachment (6) being designed to travel over the surface of the workpiece (11, 11'), characterised in that at least one sensor (20, 21) detects one edge (15) of the workpiece (11, 11') located in the traverse path (14, 14'; 17, 17') of the grinding attachment (6), that a controller limits the traverse path (14, 14'; 17, 17') in accordance with the detected edge (15) and reverses the direction of movement of the grinding attachment (6), that the pressure bar (8) consists of a number of pressure shoe elements (18), which can be individually set to an operating position, and that the setting of the pressure shoe elements (18) to the operating position can be controlled by the at least one sensor (20, 21).
2. Grinding machine according to Claim 1, characterised in that after the direction reversal, the controller guides the sanding attachment (6) along another traverse path (14', 17') over the workpiece.
3. Grinding machine according to Claim 2, characterised in that for the direction reversal the grinding attachment (6) is displaced onto a traverse path (14', 17') which is parallel to the completed traverse path (14, 17).
4. Grinding machine according to Claim 3, characterised in that after sweeping over the surface of the workpiece (11, 11') in first parallel traverse paths (14), the grinding attachment is slewed through 90° and is moved over the surface along second parallel traverse paths (17) lying perpendicular to the first parallel traverse paths (14).
5. Grinding machine according to one of Claims 1 to 4, characterised in that the grinding attachment (6) is swivel-mounted on a swivelling axis (7) on an X-Y traversing device (3, 4), perpendicular to the feed plane (10) of the workpiece.
6. Grinding machine according to one of Claims 1 to 5, characterised in that the at least one sensor is formed by sensor strips (20, 21) arranged parallel to the pressure bar (8) at the leading or trailing edge of the grinding attachment (6).
7. Grinding machine according to one of Claims 1 to 6, characterised in that the grinding attachment (6) is mounted in a height-adjustable manner.
8. Grinding machine according to one of Claims 1 to 7, characterised in that the grinding attachment (6) is equipped with at least one proximity sensor.
9. Grinding machine according to Claims 7 and 8, characterised in that the height adjustment of the grinding attachment (6) is effected automatically in relation to the measuring signal of the proximity sensor.
10. Grinding machine according to one of Claims 1 to 9, characterised in that the pressure bar (8) has a spherical camber which is perpendicular to the direction of travel of the grinding belt (12).
11. Grinding machine according to one of Claims 1 to 10, characterised in that the feed plane (10) of the workpiece is formed by a stationary work table (1).
12. Grinding machine according to one of Claims 1 to 11, characterised by the use of capacitive sensors (22) in at least one sensor strip (20, 21).

Images