Method and device for separating disc-shaped bodies from an original body

ES 2 179 026 T3

DESCRIPTION

Procedure and device for cutting slice-shaped bodies from an initial body.

The invention relates to a method and to a device for cutting bodies in the shape of a slice from an initial body, illuminating the surroundings of the front surface of the initial body, recognizing the corresponding front surface of the initial body with an optical recognition equipment using contrast between the environment of the front surface and the front surface, The slice thickness required for a slice weight determined from the specific mass of the initial body and the front surface is calculated and the slice-shaped body cut is controlled based on the value thus calculated.

Many foods such as cheese, ham, sausages, etc. They arrive at the store completely packed and cut, supplying a relatively high proportion as the so-called merchandise equal to a fixed weight. When cutting the products, the fixed weight must be complied with as accurately as possible, according to the tolerances prescriptions of the complete packaging law. This is achieved all the worse the stronger the oscillations in the product section within a product string, but also between one string and the next. For this reason, procedures are used for the registration of the product section in time, which allow an adaptation of the advance of the product at the moment in which a variation of the section takes place.

In DE-PS 28 20 583 C2 and in EP 246

668 A2 describes a procedure in which the weight of the slices already cut is measured with a scale and the advance is adjusted as a function of the total weight measured. This procedure is complicated and slow, since each balance requires a certain time to reach its equilibrium position. A fast weighing fails due to the laws of physics, such as oscillation processes until stabilization, poor filtering of disturbances, etc. and the inevitable time lag between the weighing process and the cutting process.

Furthermore, for example, from USPS 4, 557, 019 procedures based on a scan of the surface of the products before the cutting process are known. Here, for example, the outer casing of the original body to be cut is explored by means of a triangulation procedure before the cutting process and the advance is subsequently adapted during the cutting process as a function of the previously calculated volume or the registered sections. But due to the lack of shape of the products, the exact positioning is lost during transport to the cutting box and when gripping the products by means of a gripper, mainly due to the crushing movement that this implies. Thus, the effective section was displaced with respect to the calculated one. Due to the limited number of shots, shadow areas are presented depending on the effective shape of the product, in which the surface is not correctly registered. In addition, hollow places and large deformations generally lead to volume overestimations. Even when illumination and soiling of the exploration equipment are relatively unproblematic in this procedure, the effective area of ​​the section is not determined with sufficient precision.

DE-OS 38 08 790 A1 describes a procedure for recording the cutting surfaces during the cutting process in which the cutting surface is irradiated with lighting bodies and it is captured, taking advantage of the reflection behavior, with a CCD camera. Both the camera and the lighting fixtures are arranged frontally in front of the cutting surface. The process reaches its limitations when the caodan height is chosen sufficiently large for cutting reasons, for example in portions which, due to their increasing height or special cutting techniques, become very close to the cutting surface. . In addition, problems arise when it comes to cutting equipment that works with high cutting powers of up to 2,000 cuts per minute.

For these high speeds, the already cut slice falls while the image is already being taken for the next slice that is still in front of the cutting device. The socket and the angle of illumination must for this reason be very flat and it is almost impossible to carry out an illumination without casting disturbing shadows or an uncontrolled return reflection. In addition, the camera and lighting must be located in areas with extremely high contamination.

The aforementioned drawbacks could be reduced with the cutting device described in DE-PS 37 14 199 C2, by arranging the lighting elements directly behind the cutting plane next to the cutting blade. By direct determination of the cutting area, the effective area of ​​the section can be very accurately recorded. But in the device described there is the problem that the image quality is affected by reflections and shadow formation when dealing with different initial bodies and due to the formation of shadows caused by additional elements of the cutting device, such as for example holding arms.

In US Pat. No. 5,129,298 a cutting device is described in which the outline of an initial body is illuminated with dark field lighting. For this, three lighting elements are arranged behind the initial body to illuminate an opaque glass, to guide light rays obliquely from above in the longitudinal direction of the initial body on the upper cutting edge and obliquely from the side on the lateral edges. Through reflections and shadows, the quality of the lighting can however be affected. Furthermore, recesses and recesses on the bottom of the product cannot be recognized.

Therefore, the task of the invention was to indicate a procedure and a device for cutting

ES 2 179 026 T3 bodies in the form of a slice of an initial body, in which the above-mentioned problems are avoided.

In the procedure, the environment of the front surface of the initial body must be illuminated, the corresponding front surface of the initial body must be recognized with a recognition equipment Optically with the help of the contrast between the environment of the front surface and the front surface, the thickness is calculated of slice required for a predetermined slice weight based on the specific mass of the initial body and the front surface, the cut of the body in the form of a slice being controlled with the value thus calculated.

The device must have a cutting equipment, an advance equipment to advance the initial body towards the cutting equipment, an optical recognition equipment to determine the contour of the front surface of the initial body and lighting bodies to illuminate the environment. of the cutting surface, the recognition equipment determining the front surface with the aid of the contrast between the environment of the front surface and the initial body and the advance of the initial body being carried out as a function of the calculated front surface.

The task is solved by means of the procedure corresponding to invention 1, in such a way that the initial body is guided in a tunnel and the initial body is illuminated with multiple lighting bodies, which are superficially along the longitudinal direction of the body. initial in the tunnel.

Correspondingly, the device has, according to the characteristic features of claim 6, multiple lighting bodies, arranged along the longitudinal direction of the initial body. In this way, a uniform and high contrast illumination of the environment of the front surface is ensured.

It was observed that disturbing reflections and shadow formation can be greatly reduced by surface arrangement of lighting body in a tunnel.

Among others, from DE-PS 42 06 196 C2 it is known to use a feed tunnel together with cutting machines. Traditional advance tunnels are, however, used only for safety reasons and for better steering of the initial body.

It was observed that a tunnel is also advantageously suitable for better illumination of the cutting edges of the initial body, when multiple lighting elements are arranged in the tunnel.

Because the lighting bodies form a tunnel, which begins at a sufficient distance from the cutting equipment or cutting plane and ends at the cutting equipment, the initial body is illuminated uniformly around it. Shadow formation can be reduced and contrast increased by housing the lighting fixtures in a tunnel of reflective material. The tunnel advantageously has up to four zones, which provide different radiations. In a first area, diffuse radiation is produced with a reduced intensity towards the cut-off plane. The first zone is made up of the front surface of the tunnel together with the cut surface, the central zone of the tunnel cover, the front and central part of the side walls and the floor of the tunnel.

Advantageously, the lighting bodies can be individually adjusted, for example by individually orienting the radiation equipment of the lighting bodies, the latter being, for example, able to be moved by motor. Advantageously, the adjustment of the lighting bodies is carried out by means of the corresponding control system, which has a memory to store the settings for the lighting bodies. Thus, the settings can be made once for different ambient conditions and can be recalled at all times without great cost and the lighting fixtures adjusted according to the defined ambient conditions.

Since the lighting bodies are controlled by pulse and the recognition equipment by impulse, a heat formation that could damage the product is avoided and the contrast of the shot is increased, as well as the distance of disturbance in front of the ambient light.

Advantageously, the lighting bodies are readjusted in service, the control evaluating the reflection signals and the contrast information of the recognition equipment and the lighting bodies being adjusted in such a way that reflections are minimized and the contrast is increased.

In a second zone, radiation oriented towards the cutting plane is provided. This second area is formed by the front part of the tunnel cover next to the cutting plane and serves especially to illuminate additional elements, such as elements to hold the products. In a third area, radiation oriented obliquely forward, towards the cutting plane, is provided so that the cutting edge is illuminated and contrast increases. The third zone is formed by the back of the tunnel cover.

In a fourth zone a radiation directed precisely on the initial body is produced. This fourth area is formed at least by the central area of ​​the side wall that was exposed. This area serves to illuminate the lateral surface of the initial body.

It is particularly advantageous that at least the side wall on which the initial body rests can slide. The front surface can then be optimally oriented and captured. By moving the side walls, the lighting conditions can also be optimized.

The invention is described below on the basis of the attached drawings. Shown in:

Figure 1 a schematic device for cutting slice-shaped bodies, in longitudinal section with respect to the direction of transport;

figure 2 a front view of the device;

figure 3 a perspective view of the lighting frame for the device;

Figure 4 a longitudinal section view of the lighting frame.

ES 2 179 026 T3

Figure 1 shows a schematic view of the device for cutting bodies in the form of a slice 1 from an initial body 2, in which the initial body 2 rests on an advancing equipment and is brought by east to an equipment of cutting 4. The cutting unit 4 is, in the exemplary embodiment shown, an eccentric rotating circular blade. In the vicinity of the cutting surface 5, the initial body 2 is supported by a lighting frame 6. The upper part of the initial body 2 is guided by a restraint team 7; inclined in the direction of transport T.

The lighting frame 6 and the advance equipment 3 are inclined, so that the transport equipment T forms an angle of about 45 ° with respect to the horizontal. The slice-shaped bodies 1 then fall down due to the force of gravity and are transported out of the cutting equipment 4 by an extraction belt 8. The extraction belt 8 is a horizontal conveyor belt. The cutting surface of the initial body 2 is captured by a camera 9, arranged to the right in front of the cutting surface and at a relatively open angle relative to it. The intake angle must be relatively open, especially for very high cutting powers, so that already during the fall of an already cut slice, the next slice that is still in front of the cut can be captured. Illumination elements 10a, 10b, 10c are housed in the lighting frame 6, which radiate downwards towards the cutting edge of the initial body 2.

Figure 2 shows the device in front view. The initial body 2, for example sausage, ham, cheese, etc., rests on the lighting frame 6 and is irradiated by the lighting elements 10a, 10b, 10c, housed in the lighting frame 6. The cutting equipment 4 is in this exemplary embodiment a circular blade, which rotates around its axis, the axis of rotation being eccentrically supported. In this way, the caclic slice-shaped bodies 1 are separated and then from the initial body 2. The chamber 9 is arranged at an open angle to the right of the cutting surface 5 and the lighting frame 6 and captures the entire aperture. of the lighting frame 6. It can be seen that the lighting frame 6 forms a tunnel, which is traversed during the cutting process. This tunnel begins, as seen in figure 1, at a sufficient distance from the cut surface and ends at the cut surface. The camera 9 captures both the cutting surface 5 as well as the front area of ​​the lighting frame 6 directly. A reconnaissance equipment 11 connected to the camera 9 evaluates the contours between the cutting surface 5 and the opening of the lighting frame and determines the corresponding front surface of the initial body 2. From the previously determined specific mass of the initial body 2 and the calculated front surface, the necessary slice thickness is then calculated for a predetermined slice weight. The advance equipment 3 is controlled by the recognition equipment 11 in such a way that in the next cut the corresponding slice thickness is separated from the initial body 2.

The capture of the cut surface is carried out in the procedure described for taking images as a dark field, that is, the surroundings of the cut surface 5 are brightly illuminated and the cut surface 5 appears dark. For this, as seen in figure 3, the lighting frame 6 is divided into several zones I, II, III, IV, in which the adjustable lighting elements 10 are housed. The lighting elements 10 are set differently in different zones. The parts registered directly by the camera of the lighting frame 6 form the background for the contour of the product and should appear diffuse and weak. For this reason, the lighting bodies 10 are oriented in such a way that the zone I presents a diffuse radiation, that is to say, that the radiation intensity is reduced towards the cut-off plane, also radiating at the edge. Zone I is made up of the front edge of the lighting frame 6, a transverse band in the center of the cover 12 and the free side wall 13 of the lighting frame 6, the front side edge and the side wall on which it rests. the initial body 2.

In zone II a rearward-facing field is provided to illuminate existing auxiliary elements, such as the retention device 7, so that they do not cause disturbing shadows on the irradiated surface of the initial body 2. The auxiliary elements can also be equipped with elements of additional lighting housed there. Through zone II the surface of the initial body 2 is also illuminated, to avoid shadows, for example due to the undulation of the surface of the product. Zone III is located in the front zone of the cover 12 of the lighting frame 6.

In the rear area of ​​the deck 12, seen against the direction of transport T, a zone III is provided, which provides radiation oriented forward in the direction of the edge of the initial body 2. The radiation equipment is oblique, to let the radiation through the initial body 2 be as low as possible. By direct irradiation of the edge, the outline of the initial body is highlighted 2.

On the side wall 13 that is exposed to the lighting frame 6, in its central part, there is a zone IV, which provides radiation directed directly onto the initial body 2. The other side wall, on which the initial body, can be movable.

The lighting fixtures housed in zones I to IV can be adjusted manually or automatically, so that the lighting conditions in the initial fixture 2 and certain configuration conditions, such as additional auxiliary equipment and retention devices 7 special can be adapted to the product. For this, a control system (not shown) can be provided, which has a memory, in which the settings of the lighting bodies 10 determined for different environmental conditions are stored. In addition, the control system is configured in such a way

ES 2 179 026 T3 that the various lighting bodies 10 can be adapted not only for the basic setting, but also to cope with variations during the cutting process. For this, the control system is linked by means of an interface with the recognition equipment and with the actuators of the lighting bodies 10, with which the recognition equipment detects disturbing reflections and contrast blurring and supplies the corresponding information to the detection system. control for the subsequent regulation of the lighting fixtures 10.

The recognition equipment 11 must be able to carry out a correction, depending on the pixel position of the recognized image, of the surface or the edge of the surface, to compensate for distortions due to viewing angle and distortions of the optical lens. chamber 9. In this way a correct determination of the surface of the section is possible. This elimination of distortions should preferably be carried out by means of the corresponding hardware, so that for each cut an evaluation of the image and an adaptation of the advance can be carried out immediately.

Figure 4 shows the lighting frame 6 in longitudinal section. From the evolution of radiation, which is different in the different zones I, II, and III, it can be deduced that the initial body 2 is superficially irradiated along its longitudinal direction, anticipating different illuminations and radiation directions.

A first section A extends from the cut surface 5 in the longitudinal direction of the initial body 2 in the opposite direction to that of the transport T. This section A has a reduced radiation intensity, especially due to the fact that the light in zone II is directed backwards and the lighting bodies 10 in section A emit diffuse radiation with low intensity. The section B, which when viewed in the opposite direction to that of the transport T, is behind the section A, presents a high intensity of radiation. For this, the lighting bodies 10 in zone I are controlled in such a way that they emit a very bright light. A third section C in the area of ​​the edge of the cutting surface 5 is also irradiated with a very high intensity, controlling the lighting bodies 10 in the area III in a corresponding way.

It is particularly advantageous if the different lighting bodies 10 are controlled in a pulsating manner, so that the heat build-up is negligible. To do this, the camera 9 and the recognition equipment 11 conveniently operate by means of impulse activation, so that a good contrast of the shot and a high disturbance distance against the surrounding light are thus ensured. In addition, an additional suitable lighting equipment can be arranged in front of the front surface 5, whereby the dark field can be evaluated for example to distinguish fatty zone meat and muscles, or for example an existing hole in a cheese and include it in the weight calculation. The control of the intensity of radiation of the lighting bodies 10 can also be carried out by providing on the inner surface of the lighting frame 6 a translucent element, for which the permeability of light can be controlled. The element can, for example, be made as an LCD display unit with a control matrix, the different areas of the element can be controlled separately. A large number of elements can also be provided, such that each one can be adjusted independently with a certain permeability of light for the entire element.