EP0547095B1 - Device for controlling the displacement of a tool along the edge of glass panes - Google Patents

Abstract

PCT No. PCT/EP91/01677 Sec. 371 Date Mar. 2, 1993 Sec. 102(e) Date Mar. 2, 1993 PCT Filed Sep. 5, 1991 PCT Pub. No. WO92/04521 PCT Pub. Date Mar. 19, 1992.The apparatus comprises a horizontal conveyor (1), on which the glass panes (4) are conveyed while they are supported by backing means (2), which by their supporting forward surface define a plane of pane travel (3), a tool (18) for processing the glass panes (4) along their edge and a drive motor for displaying the tool (18) in a direction which is parallel to the plane of pane travel (3) and transverse to the direction of travel (5). For a control of the movement of the tool (18), electronic line cameras (8) are provided, which are so directed toward the plane of pane travel (3) that their scanning lines extend in or parallel to the plane of pane travel and at right angles to the direction of travel (5). For measuring the distance traveled, a displacement pick-up (15) is provided, which is synchronized with the horizontal conveyor (1). The signals from the line cameras (8) and from the displacement pickup (15) are delivered to an evaluating computer (16) for controlling the tool (18).

Description

Technical field:

The invention relates to a device for controlling the movement of a tool along the edge of glass panes, in particular insulating glass panes, with a horizontal conveyor, on which the glass panes are supported by a support device, which defines a pane running plane with its front, which provides the support, with one or more optical sensors which scan the glass panes and with a drive motor for moving the tool parallel to the plane of the pan transverse to the conveying direction of the horizontal conveyor (1).

State of the art:

Such a device is known from DE-C-28 16 437. In the known device, a nozzle for sealing the edge joint of insulating glass panes is controlled by a light barrier which is moved along with the sealing nozzle and indicates when the nozzle reaches a corner of the insulating glass pane. The light barrier then controls the drive of the nozzle so that the nozzle on the corner of the insulating glass pane is pivoted by 90 ° and then moves along the subsequent section of the edge of the insulating glass pane. This type of control is good for rectangular insulating glass panes, but is less suitable for controlling the movement of a tool along the edge of individual glass panes or insulating glass panes that have a shape that deviates from the rectangular shape - so-called model panes. In order to control the movement of a tool along the edge of model panes, it is known to use a numerically controlled drive for the movement of the tool and to store selected shapes of model panes in a data memory and each time a glass pane with a stored shape is used for Processing is pending, the characteristic shape data is read out by a computer and the tool is controlled accordingly. The disadvantage here is that glass panes, the shape of which is not saved, cannot be processed automatically, but must be processed by hand. Another disadvantage is that the numerical control of the tool has to be communicated in some way when a model pane is to be processed and what shape it has, for example by first capturing the glass pane in terms of shape and size and by attaching a machine-readable data carrier can be coded, which is read in the processing device by a reading device which is connected to the computer which controls the movement of the tool (EP-A-0 252 066), or in that by detailed, computer-aided production planning from the outset for an entire production cycle, the dimensions of the glass panes to be processed and the order in which they are fed to the processing are determined and specified. However, most companies that process glass panes are not equipped for such detailed production planning; in view of the constant change in format of the glass panes to be processed, it would also not be flexible enough.

Presentation of the invention:

The present invention has for its object to provide a device for controlling the movement of a tool along the edge of glass panes, with which both rectangular glass panes and arbitrarily designed model panes as they come, so in any order, without detailed production planning and can be processed automatically without attaching machine-readable data carriers.

This object is achieved by a device for controlling the movement of a tool along the edge of glass panes, in particular insulating glass panes, with a horizontal conveyor on which the glass panes are conveyed supported by a support device which defines a pane running plane with its front which provides the support, with one or more optical sensors, which scan the glass panes, and with a drive motor for displacing the tool parallel to the disk running plane, transversely to the conveying direction of the horizontal conveyor, in which one or more electronic line cameras are provided as optical sensors, which are thus arranged against the pane running plane that the scanning lines lying in or parallel to the disk running plane each extend at right angles to the conveying direction, that a displacement sensor synchronized with the horizontal conveyor is provided for measuring the conveying path, and that ei n Evaluation computer is provided which is connected on the input side to the output of the line scan camera (s) and to the output of the displacement sensor and on the output side to the drive motor of the tool. Advantageous developments of the invention are the subject of the dependent claims.

In accordance with DE-C 28 16 437, the invention is based on the fact that the glass panes, preferably standing upright, are conveyed on a horizontal conveyor which is e.g. can be a conveyor belt or a roller conveyor or horizontally moving supports that support the glass panes. In principle, the glass panes can also be conveyed horizontally. The support device can e.g. act as an air cushion wall, the front of which defines the disk running plane, or about a height-adjustable horizontal row of support rollers (DE-C-30 38 425) which support the glass sheets standing on a horizontal conveyor near their upper edge, or about a field of Support rollers or support rollers, which define the disc running plane with their common front tangential plane, or also one or more conveyor belts or suction conveyor belts driven synchronously with the horizontal conveyor (EP-A-0 222 349), which can also form the horizontal conveyor at the same time.

A drive motor is provided to move the tool parallel to the disc running plane (in particular at right angles) to the conveying direction of the horizontal conveyor, which can be, for example, an electric stepper motor. For scanning the glass panes and controlling the drive motor of the tool, one or more electronic line cameras are provided according to the invention, which have an image field made up of one or more lines and are directed against the plane of the pane in such a way that the scanning line (s) of the respective line camera that are located on one another the pane running plane or onto the glass pane located in the pane running plane is or are extended at right angles to the conveying direction of the horizontal conveyor.

The line camera therefore sees where a scanning line sweeps over the respective glass pane, the extent of the glass pane at right angles to the conveying direction. Since the glass pane is moved across the scanning line by the horizontal conveyor, the respective line camera sees e.g. the height of the glass pane depending on its length. In order to determine the shape of the respective glass pane, only the slip-free movement of the glass pane on the horizontal conveyor must therefore be recorded in addition to the height supplied by the respective line camera. For this purpose, a displacement sensor synchronized with the horizontal conveyor is additionally provided according to the invention, which allows a measurement of the conveying path. The encoder can e.g. act as an incremental rotary encoder, which sits on a shaft driven synchronously with the horizontal conveyor and transmits electrical impulses proportional to its movement increments to an evaluation computer, to which the output signals of the line scan cameras are also fed. The evaluation computer thus has full information about the extension of the glass panes in two dimensions, namely in the conveying direction and transverse to the conveying direction, and thus has all the information necessary to control the movement of a tool along the edge of the glass panes . The outline of the glass panes is not subject to any restrictions. Both rectangular and arbitrarily controlled model disks can be machined automatically without the sequence in which they are fed to the machining tool having to be determined beforehand.

The type of processing tool is not important; it can be a nozzle with which the edge joint an insulating glass pane is sealed, it can be a grinding tool with which a coating is removed along the edge of a glass pane, it can also be a tool with which a prefabricated, plastic spacer in the form of a strand on a glass pane along its Edge is applied.

The respective line scan camera is preferably directed at an angle different from 90 ° to the conveying direction against the disk running plane or perpendicular to the conveying direction, but at an angle different from 90 ° to the disk running plane. This makes it possible to provide a light source directed against the pane running plane on the same side of the pane running plane as the line camera, and in such an arrangement that the glass panes reflect a substantial part of the light emanating from the light source to the line camera, so that the line camera clearly recognizes the glass pane can. To increase the contrast, a blackened surface is preferably provided on the side of the pane running plane facing away from the light source, which swallows light that has passed through the glass pane, but does not reflect it to the line scan camera.

Basically, a single line scan camera is sufficient to determine the shape of the glass panes. The lens of the line scan camera has a predetermined opening angle, and in this opening angle the pane format, namely the extent of the glass panes must fit in transversely to their conveying direction. To increase the measuring accuracy, it may be advantageous, particularly in the case of larger glass panes, to provide not just one, but two or even more line cameras and to arrange them in such a way that their object-side scan lines are aligned with one another, the scan lines of adjacent line cameras preferably partially overlapping one another. If the position of the line cameras is known, the evaluation computer can determine the shape of the glass panes from the combination of the signals from the line cameras in a manner corresponding to that from the output signal of an individual line camera.

It is not necessary to move the line scan cameras to adapt to different lens formats. They are therefore expediently arranged in a fixed position and are only adjustable. However, it is also entirely possible to obtain a high measurement resolution with only one line camera, even with large glass panes, by arranging a line camera to be displaceable at right angles to the direction of conveyance parallel to the pane running plane by means of a stepper motor and additionally providing a displacement sensor synchronized with the stepper motor, the output of which is also is connected to the evaluation computer. By means of the stepper motor, such a line camera can proceed transversely to the conveying direction, starting from a position in which an edge, in particular the lower edge of a glass sheet standing on a horizontal conveyor, lies in the field of view of the line camera be adjusted until the opposite edge of the glass pane appears in the field of view of the line scan camera. The evaluation computer then only has to add the measurement number obtained from the output signal of the line camera to the measurement number which is obtained in accordance with the position of the stepping motor from the output signal of the displacement sensor coupled to it. In this way, a second line camera can be saved.

The line cameras are preferably arranged behind the support device and observe the glass panels through a recess in the support device. Behind the support device, they can be better protected against environmental influences and the glass panes remain freely accessible for inspections and handling.

Depending on the type of processing to be carried out, it may be sufficient for the tool to be displaceable only transversely, preferably at right angles, to the conveying direction of the horizontal conveyor. In other cases, in particular when the tool is a nozzle with which the edge joint of an insulating glass pane is to be filled, a rotary drive is required - as disclosed in DE-C-28 16 437 - for rotating or pivoting the tool around a perpendicular axis running to the disc running plane; in this case, the evaluation computer is expediently also connected to the rotary drive on the output side and controls the rotary movement of the Tool, such as the rotation of a nozzle when it has reached a corner of an insulating glass pane. In this case, the evaluation computer preferably transmits not only a control signal to the drive motor which moves the tool transversely to the conveying direction of the horizontal conveyor, but also to the rotary drive of the tool a further signal which indicates the inclination or inclination of the glass pane in relation to the conveying direction. This signal can be obtained by differentiating the signal obtained with the aid of the line camera, which contains the dimension of the glass pane measured transversely to the conveying direction, according to the conveying path, which is represented by the output signal of the displacement sensor synchronized with the horizontal conveyor. The signal transmitted to the rotary drive is therefore mathematically the first derivative of the signal which is transmitted to the drive motor which shifts the tool transversely to the conveying direction. In this way, an automatic adjustment of the tool position to the contour of the pane edge is possible, even if the edge of the glass pane is curved as desired. In this way it can be ensured, for example, that a tool, for example a sealing nozzle, is oriented at a constant angle to the respective tangent at the edge of the glass pane.

In principle, the arrangement of the line scan cameras in relation to the tool can be selected so that the tool is controlled on-line. Depending on the type of tool and the processing to be carried out, however, it may be more advantageous to determine the shape of a glass sheet before it reaches the tool. In this case, the evaluation computer is preferably equipped with a memory for temporarily storing the observed dimensions of the glass panes, from which the data for the control of the tool are called up with a time delay. It is a major advantage of this measure that the stored data for controlling different tools, which are used in succession to carry out different processing operations on glass panels, for example grinding and coating, can be called up repeatedly from the memory. Another advantage of this measure is that it allows the measurement resolution to be increased. Since a finite time is required for the recording, buffering and evaluation of the image signals of each line, but the glass plate travels a certain distance during this time due to its advancing movement, the dimension of the plate in the direction of the scanning lines cannot be continuous, but only in predetermined ones temporal and thus spatial distances can be determined. The smaller the spatial distance (resolution) of two scanning lines, the more perfectly a tool can be guided along the edge of a glass pane. The easiest way to increase the resolving power is to reduce the conveying speed of the glass pane. However, this is disadvantageous for the economy of the device. It is better to use line scan cameras, the field of view of which consists not only of a single line, but of several lines parallel to each other. Such a multi-line line camera can differ from a single-line Differentiate line scan cameras, for example, in that they contain a multi-line CCD (CCD array) instead of a single-line CCD as a light-sensitive receiver. The image signals recorded in the lines of such a multi-line charge-coupled receiver can be successively buffered and evaluated, for example in such a way that if the signals of one line are buffered and the signals that have already been buffered on another line are evaluated, those that originate from a third line and already evaluated signals can be used to control the tool. In this way, the resolution can be increased in proportion to the number of lines of the line scan cameras.

ways for carrying out the invention:

Figur 1

zeigt die Vorrichtung in einem Horizontalschnitt,

Figur 2

zeigt die Vorrichtung in einer Vorderansicht,

Figur 3

zeigt die Vorrichtung in einer Rückansicht, und

Figur 4

zeigt eine Abwandlung der in Figur 3 gezeichneten Vorrichtung mit nur einer Zeilenkamera, welche höhenverstellbar ist.

Two embodiments of the invention are shown schematically in the accompanying drawings and are described below.

Figure 1

shows the device in a horizontal section,

Figure 2

shows the device in a front view,

Figure 3

shows the device in a rear view, and

Figure 4

shows a modification of the device shown in Figure 3 with only one line camera, which is adjustable in height.

As a horizontal conveyor 1, the device has a row of synchronously driven rollers which are attached to a frame (not shown). Above the horizontal conveyor, a wall extends as the support device 2, which is carried by the same frame as the horizontal conveyor and is arranged inclined a little to the rear. The wall can be designed as an air cushion wall, which has bores from which air is blown out. The front of the wall, over which the horizontal conveyor 1 protrudes, defines a pane running plane for glass panes 4, which are conveyed standing on the horizontal conveyor 1 and leaning against the wall 2 in the direction of arrow 5.

In the wall 2 there is a vertical slot 6 and behind it are in a protective housing 7 at some distance from the wall two electronic line cameras 8 and 9 on one side of the slot and a number of essentially vertically extending, rod-shaped lamps 10 on the other Side of the slot 6 arranged; the arrangement is such that a significant part of the light incident on the glass pane 4 located beyond the slot 6 is reflected by the lamps 10 in the direction of the cameras 8 and 9. On the front of the wall 2, at a distance from the wall covering the slot 6, a black plate 11 is provided, which swallows light passing through the glass pane 4 and at the same time prevents stray light from the front of the wall 2 through the slot 6 falls on cameras 8 and 9. The two cameras have overlapping fields of view 12 and 13, characterized by an aperture angle α. They serve to scan the glass pane 4 line by line and are aligned for this purpose in such a way that the scanning line of the upper line camera 8 projected onto the pane running plane 3 or onto the glass plate 4 is aligned with that of the lower line camera 9. The distance between the line cameras 8 and 9 from one another and from the horizontal conveyor 1 is predetermined.

An incremental rotary encoder 15 is attached to a driven shaft 14 of the horizontal conveyor 1, the output signals of which, like the output signals of the two cameras 8 and 9, are fed to an evaluation computer 16. The output of the computer is connected to the drive motor 17 of a tool 18, which can be moved up and down on essentially vertical guide rods 19 parallel to the plane of the disk running, which are arranged behind a further slot 20 of the wall 2, which is viewed in the direction of conveyance 5 is located some distance behind the slot 6. The tool 18 reaches through the slot 20 in order to process the glass pane 4 along its edge as soon as it comes into the area of action of the tool 18.

The device works as follows:

As soon as a glass pane 4 comes into the field of view 12, 13 of the two line cameras, the two line cameras record the height h of the glass plate, which in the example shown is a model plate, which differs from the rectangular shape in that its upper edge is inclined . The output signals from the cameras containing the height of the glass pane 4 are fed to the evaluation computer 16, which assigns the successively determined measured values of the height to the simultaneously transmitted measured values of the incremental rotary encoder 15, so that the evaluation computer has the information of how the height h of the glass pane 4 is Depends on the feed 1 of the glass pane changes. The data that reflect this dependency are temporarily stored in a memory 21 of the evaluation computer 16 and used with a time delay to control the drive motor 17 of the tool 18. The time delay depends on the distance between the tool 18 and the position of the scanning line in the middle of the slot 6; this distance corresponds to a fixed number of up-counts of the encoder 15. Instead of starting with a time delay, the delayed response of the control of the drive motor 17 can therefore also be triggered by waiting for the predetermined number of counts of the encoder, which corresponds to the distance of the tool 18 from the Position of the scan lines corresponds; this procedure has the advantage that it allows intermittent downtimes for the horizontal conveyor.

To check the current position of the tool, its drive motor can also be connected to an incrementally operating rotary encoder 22, the output signals of which are fed to a further input of the evaluation computer 16 for checking.

The modified exemplary embodiment shown in FIG. 4 differs from the first exemplary embodiment only in that instead of two line cameras, only one line camera 8 is provided. The same and corresponding parts are designated in both exemplary embodiments with the same reference numerals. The camera provided alone can be moved up and down by a motor 31 on a guide rail 30 running at right angles to the conveying direction 5 and parallel to the wall 2. The drive shaft of the motor 31 is connected to an incrementally operating rotary encoder 32, the output signals of which are also fed to the computer 16. This modified device works as follows: In the starting position, the camera 8 is positioned so deep that its field of vision definitely captures the lower edge of a glass pane 4. The position of the lower edge is determined by the upper edge of the horizontal conveyor. As long as the upper edge of the glass pane is also in the field of view 12 of the camera 8, the camera can remain in its predetermined position. However, the upper edge of the glass pane 4 approaches the upper edge of the field of view 12 up to a predetermined one while passing the slot 6 Distance, the camera 8 is automatically moved upwards a little, the path measured by the rotary encoder 32, transmitted to the evaluation computer 16 and taken into account there when the measurement result is formed. If the upper edge of the glass pane is already outside the court field 12 at the beginning, the camera is raised at the beginning so that the upper edge of the glass pane 4 lies in the field of view 12.

Commercial Applicability:

The invention is applicable for controlling processing operations on the edges of glass sheets, in particular in insulating glass production lines.

Claims (14)

1. An apparatus for controlling the movement of a tool (18) along the edge of glass panes (4), particularly of insulating glass panes, comprising
      a horizontal conveyor (1), on which the glass panes (4) are conveyed while they are supported by backing means (2), which by their supporting forward surface define a plane of pane travel (3),
      one or more optical sensors (8, 9) for scanning the glass panes (4),
      and a drive motor (17) for displacing the tool (18) in a direction which is parallel to the plane of pane travel (3) and transverse to the direction of travel (5) of the horizontal conveyor (1),
      characterized in that the optical sensors consist of one or more electronic line cameras (8, 9), which are so directed toward the plane of pane travel (3) that their scanning lines extend in or parallel to the plane of pane travel (3) and at right angles to the direction of travel (5),
      a displacement pickup (15) for measuring the distance travelled is synchronized with the horizontal conveyor (1),
      and an evaluating computer (16) is provided, which is connected at its input to the output of the line camera(s) (8, 9) and to the output of the displacement pickup (15) and at its output to the drive motor (17) of the tool (18).
2. An apparatus according to claim 1, characterized in that the line camera(s) (8, 9) is or are directed toward the plane of pane travel (3) at an angle (β) other than 90° to the direction of travel (5).
3. An apparatus according to claim 1, characterized in that the line camera(s) (8, 9) are directed at right angles to the direction of travel (5) but is or are directed toward the plane of pane travel (3) at an angle other than 90° to said plane.
4. An apparatus according to any of the preceding claims, characterized in that at least two line cameras (8, 9) are provided and on their object side have scanning lines aligned with each other and the scanning lines of adjacent line cameras (8, 9) overlap in part.
5. An apparatus according to any of the preceding claims, characterized in that the line camera(s) (8, 9) are adjustable but in other respects are stationary.
6. An apparatus according to any of claims 1 to 4, characterized in that only a single line camera (8) is provided,
      said one line camera (8) is displaceable by a stepping motor (31) in a direction which is at right angles to the direction of travel (5) and parallel to the plane of pane travel (3),
      and a displacement pickup (32) is synchronized with the stepping motor (31) and has an output which is connected to an input of the evaluating computer (16).
7. An apparatus according to any of the preceding claims, characterized in that a light source (10) which is directed toward the plane of pane travel (3) is provided on the same side of the plane of pane travel (3) as the line camera(s) (8, 9).
8. An apparatus according to claim 7, characterized in that a blackened surface (11) is provided on that side of the plane of pane travel (3) which faces away from the light source (10).
9. An apparatus according to any of the preceding claims, characterized in that the line camera(s) (8, 9) are arranged behind the backing means (2) and view the glass plates (4) through an aperture (6) in the backing means (2).
10. An apparatus according to any of the preceding claims, characterized in that the tool (18) comprises a rotary drive for rotating or pivotally moving the tool (18) about an axis that extends at right angles to the plane of pane travel and that the output of the evaluating computer (16) is connected also to the rotary drive.
11. An apparatus according to claim 10, characterized in that the evaluating computer (16) delivers to the drive motor (17) of the tool (18) a control signal which represents the dimension h of the glass pane (4) in a direction which is transverse to the direction of travel of the horizontal conveyor (1) in dependence on the output signal 1 of the displacement pickup (15) that is synchronized with the horizontal conveyor (1) and the evaluating computer (16) delivers to the rotary drive of the tool (18) a signal which represents the first derivative dh/dl of the dimension h.
12. An apparatus according to any of the preceding claims, characterized in that the evaluating computer (16) comprises a memory (21) for a temporary storage of the detected dimensions of the glass panes (4).
13. An apparatus according to any of the preceding claims, characterized in that the line cameras (8, 9) have a field of view composed of a plurality of lines.
14. An apparatus according to any of the preceding claims, characterized in that the line cameras (8, 9) comprise a light-sensitive receiver consisting of a single-line or multi-line CCD array.

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