ANIMAL SKIN STRETCHING DEVICE

Abstract

Device (1) for stretching animal hide (2), comprising a support surface (3) for supporting the animal hide (2), a first pair (4), and a second pair (5) on tensioning elements (6) attachable to substantially opposite edge regions of the animal hide (2), wherein the tensioning elements (6) are connected to a tensioning device (8) for applying a tensile stress to the tensioning elements (6), and each pair (4, 5) of tensioning elements (6) forms a tension line (9) in the animal hide (2) when subjected to the tension, wherein the tension line (9) of the first pair (4) forms an acute angle with the tension line (9) of the second pair (5).

Description

[0001] The invention relates to a device for stretching animal hide according to the preamble of claim 1.

[0002] Leather production involves a series of mechanical and chemical processes that transform an animal hide into a finished leather hide. Because leather is used in a wide variety of applications, the quality of the hide must be determined before and after various processing steps to ascertain for which application the finished leather hide, or specific sections thereof, are suitable. The value of a leather hide is also significantly influenced by the quality of the finished product.

[0003] The inspection of leather hides is carried out according to the state of the art using visual inspection methods, either manually by a person or automatically using a camera system. Several different testing devices are used for the quality control of animal hides to check various quality criteria. Abrasion resistance is tested using a Taber, Veslic, or Martindale tester. Flexometers are used to test crease resistance. A flame test checks flammability. Leather hides are exposed to light and UV radiation to test their lightfastness. Another device measures the color of the hide's surface. Finally, the finished leather hides are tested for strength (e.g., tensile strength, tear strength, elasticity).Finally, a manual and visual final inspection takes place, in which the quality with regard to skin damage of the leather is essentially assessed as a quality criterion.

[0004] For example, a wide variety of skin damage is known in cowhide, resulting from injuries, lichens, mites, cracks, fork punctures, and other causes. Each type of skin damage has a typical appearance; fork punctures, for instance, have a small, round circumference, while damage from fattening folds has elongated, parallel outlines.

[0005] Devices for stretching animal hides are used in leather production as part of quality control to more easily detect damage to hides. The hide is stretched, making it easier to determine the aforementioned damage or quality characteristics using previously known testing equipment. This increases the accuracy of quality control in leather manufacturing.

[0006] So-called clamping tables with manual operation are known from the prior art. In these tables, the hide is secured with a clamping frame that clamps a section of the hide, and then stretched by a movable lifting core. This core's movement stretches the fixed section from the back of the hide. Depending on the stroke height, a desired percentage of stretch can be achieved. Inspection and marking of the leather characteristics with a colored pencil are performed entirely manually.

[0007] From Austrian patent AT 509 382 A1, a device for stretching animal hides is known, which uses tensile elements subjected to a linear tensile stress to stretch the hide for subsequent quality control. In this device, which is known from the prior art, the aim is to achieve the most homogeneous stretching possible of the hide by stretching the hide along two perpendicular lines of tensile stress, with the goal of detecting as many quality defects in the hide as possible. However, due to the diverse nature of damage occurring in animal hides, some defects are still not detected during the subsequent quality control. Furthermore, the device disclosed in AT 509 382 A1 cannot stretch the hide in all directions in many peripheral areas, thus making it impossible to examine the entire hide in a single step.Furthermore, this previously known clamping system does not allow any assessment of the expected elongation values ​​that this skin will have when later processed into individual pieces.

[0008] The object of the present invention is to provide a device for stretching animal hide which avoids the disadvantages of the prior art.

[0009] According to the invention, the present problem is solved with a device for stretching animal skin having the features of claim 1.

[0010] The device according to the invention for stretching animal hide comprises a support surface for the animal hide, as well as a first pair and a second pair of tensioning elements that can be attached to substantially opposite edge regions of the animal hide. The tensioning elements are connected to a tensioning device for applying a tensile tension to the tensioning elements, with each pair of tensioning elements forming a tension line in the animal hide when subjected to the tension. According to the invention, the tension line of the first pair forms an obtuse and / or acute angle with the tension line of the second pair. By forming an obtuse and / or acute angle between the tension lines, an inhomogeneous stretching of the animal hide is achieved.Surprisingly, inhomogeneous stretching of the animal hide results in the technical effect that, depending on the stretching directions or the geometry of the tensile stress lines, a greater number of quality defects and damages in the hide are detectable during quality control than with homogeneous stretching known in the prior art, or stretching along only a single tensile stress line. This improves the detectability of damage in the hide, thereby increasing the overall quality of leather production.

[0011] According to the preferred embodiment of the device according to the invention, the device comprises at least one further pair of tension elements that can be attached to substantially opposite edge regions of the animal hide, wherein the tension line of each pair of tension elements forms an obtuse and / or acute angle with the tension line of an adjacent pair of tension elements. This offers the advantage of providing further possibilities for varying the stretching of the animal hide, thereby increasing the number of defects in the animal hide that can be visualized with the device according to the invention. Even with a subsequent, purely visual inspection of the animal hide, a significantly higher degree of detection is achieved than with inspection tables conventionally used in the prior art.

[0012] Preferably, the tensile stress lines of the pairs on the tensioning elements intersect substantially in a central area of ​​the animal hide. This offers the advantage that the largest possible area of ​​the animal hide can be stretched with the device according to the invention. The entire animal hide can thus be inspected for leather characteristics in a single clamping operation without having to move sections. In combination with a visual inspection performed by a person or by using a suitable camera system, this offers a clear advantage over commercially available systems: the entire animal hide can be processed in a single clamping position without further material handling.

[0013] According to the preferred embodiment, the device according to the invention comprises a first stop and a second stop. The clamping device is movably mounted between the first stop and the second stop, wherein the tensioning elements are essentially free of tension when the clamping device rests against the first stop, and are subjected to tension when the clamping device rests against the second stop. The stops define a range within which the animal hide can be stretched. This prevents the animal hide from being overstretched or even mechanically damaged in its structure. Preferably, the distance between the first stop and the second stop is variable.Since the hides of different animal species have different elastic limits, this offers the possibility of adapting the degree of stretching applied to the animal hide with the device according to the invention to the type of animal hide. Furthermore, this also allows the extensibility of the animal hide to be classified as a value, which is impossible with other methods of the prior art.

[0014] According to the invention, the clamping device is connected to a cable pulley, the cable pulley being designed to move the clamping device between the first stop and the second stop. This offers the advantage that a means readily available on the market for various load ranges can be used for the device according to the invention. Preferably, the device according to the invention comprises two cable pulleys connected to the clamping device.

[0015] According to the preferred embodiment of the device according to the invention, the clamping device comprises at least one receiving means for holding clamping weights. This achieves the advantage that the device according to the invention can also be operated without the use of an external energy source or power supply. Preferably, the receiving means is designed as a substantially circular plate. This is preferably arranged parallel to the support surface.

[0016] According to an advantageous embodiment, the traction elements include self-locking clamps for attaching them to the animal hide. This provides the advantage of a simple and quick fastening method that delivers a clamping force proportional to the tension, thus ensuring secure attachment of the hide to the traction elements. The clamps are designed to prevent damage to the hide being stretched.

[0017] In an advantageous embodiment, the device according to the invention comprises deflecting means for redirecting the traction elements. These are preferably arranged in an edge region of the support surface. This results in a compact design of the device according to the invention.

[0018] Preferably, the support surface is substantially circular or polygonal. Furthermore, in the preferred embodiment, the device according to the invention comprises a support block, wherein the support surface, the tensioning elements, and the clamping device are connected to the support block.

[0019] Advantageous embodiments of the device according to the invention, as well as alternative embodiment variants, will be explained in more detail below with reference to the figures. Figure 1 The device according to the invention for stretching animal skin is shown in an oblique view from above, with an animal skin attached to a support surface of the device. Figure 1a shows a self-locking pull clamp of the device according to the invention. Figure 2 The device according to the invention is shown in an oblique view from below. Figure 3 shows a first stop and a second stop of the device according to the invention. Figure 4shows a section of a clamping device of the device according to the invention. Figure 5 The clamping device according to the invention is shown with clamping weights. Figure 6 shows a course of traction elements of the device according to the invention. Figure 7 shows a support block of the device according to the invention. Figure 8 Figure 1 shows the device according to the invention in an alternative embodiment with hydraulic cylinders. Figure 9 The device according to the invention shows a support surface with recesses.

[0020] Figure 1 Figure 1 shows a device 1 according to the invention for stretching animal hide 2. The device 1 comprises a support surface 3, which serves to support the animal hide 2. The device 1 comprises a first pair 4 and a second pair 5 of tensioning elements 6, which can be attached to substantially opposite edge regions of the animal hide 2. The tensioning elements 6 are arranged in a manner that allows the animal hide 2 to be stretched. Figure 1In a preferred embodiment, the device 1 comprises eight pairs of tension members 6, the tension members 6 being shown attached to the animal hide 2. According to an alternative embodiment of the device 1 according to the invention, for example, ten to thirty pairs of tension members 6 can also be used on the device 1 according to the invention. The pairs of tension members 6 are preferably arranged circumferentially and apply tension to essentially the entire animal hide 2 in a star-shaped pattern. The tension members 6 preferably include self-locking clamps 7 for attaching the tension members 6 to the animal hide 2. A self-locking clamp 7 is in Figure 1a shown in detail. The tensioning elements 6 are connected to a tensioning device 8, which is in Figure 2 , Figure 4 and Figure 5The clamping device 8 provides a tensile stress and applies this stress to the tensioning elements 6. Each pair 4 and 5 of tensioning elements 6, subjected to the stress, forms a tension line 9 in the animal hide 2, which is Figure 1The lines are represented as dashed lines. According to the invention, the tensile stress line 9 of the first pair 4 on the tensioning elements 6 forms an obtuse and / or acute angle α with the tensile stress line 9 of the second pair 5 on the tensioning elements 6. This obtuse and / or acute angle α, formed by the tensile stress lines 9 of the first pair 4 and the second pair 5, results in inhomogeneous stretching in a portion or substantially the entire area of ​​the animal hide 2. This offers the advantage that the stretching of the animal hide 2 can be selectively adapted to the type of quality defects of interest in the hide 2. This facilitates the detection of specific quality defects and improves quality control in leather production.

[0021] According to the in Figure 1In the illustrated preferred embodiment of the device 1 according to the invention, the device 1 comprises at least one further pair of tensile elements 6 that can be attached to substantially opposite edge regions of the animal skin 2. Figure 1 The device is shown with eight pairs of tension elements 6. The tension line 9 of each pair of tension elements 6 forms an obtuse and / or acute angle α with the tension line 9 of an adjacent pair of tension elements 6. The obtuse and / or acute angle α can vary between the tension lines 9 of successive pairs of tension elements 6. This achieves the advantage that essentially the entire surface of the animal hide 2 can be tensioned with the device 1 according to the invention. Furthermore, the tension lines 9 intersect as shown in Figure 1The stretching is shown, preferably substantially in a central area 10 of the animal hide 2. This has the advantage that the animal hide 2 does not form wrinkles or tears during stretching and is therefore not damaged. According to a preferred embodiment of the device 1 according to the invention, the device 1 comprises sixteen pairs of tensioning elements 6. This distributes the tensile stress on the animal hide 2 even more evenly and reduces the force per tensioning element 6. This has the advantage of reducing the risk of individual tensioning elements 6 tearing out and increasing the safety of the operating personnel.

[0022] Figure 2 Figure 1 shows the device 1 according to the invention in a bottom view, with the clamping device 8 visible. The device 1 comprises a first stop 11, which is Figure 3is visible, and a second stop 12, between which the clamping device 8 is movably mounted. The first stop 11 and the second stop 12 are in Figure 3 shown in detail. As from Figure 3 In the preferred embodiment of the device 1 according to the invention, the distance A between the first stop 11 and the second stop 12 is variable. The tensioning elements 6 are essentially free of tensile stress when the clamping device 1 rests against the first stop 11, and are subjected to tensile stress when the clamping device 8 rests against the second stop 12. The variability of the distance A offers the advantage that the tensile stress can be adapted to animal hides of two different animal species. Figure 4 The clamping device 8 is shown section by section, wherein the clamping device 8 is in Figure 4at the second stop 12, and the tensile elements 6 are subjected to the tensile tension. The first stop 11 and the second stop 12 limit the maximum tensile tension applied to the animal skin 2 by the device 1 according to the invention.

[0023] Figure 5 Figure 1 shows the clamping device 8 of the device 1 according to the invention, which is connected to a cable pulley 13. According to the preferred embodiment of the device 1 according to the invention, the device 1 comprises, as shown in Figure 1, the clamping device 8 of the device 1 according to the invention, which is connected to a cable pulley 13. Figure 5The figure shows two cable pulleys 13 connected to the clamping device 8. The cable pulley(s) 13 move the clamping device 8 between the first stop 11 and the second stop 12. Preferably, the clamping device 8 includes a receiving element for clamping weights 14. This has the advantage that the tensile force is provided by the weight of the clamping weights 14, with the cable pulleys 13 lifting the clamping weights 14 towards the first stop 11 or lowering the clamping device 8 towards the second stop 12 by the clamping weights 14. According to an alternative embodiment, the cable pulley(s) 13 can also be used instead of the clamping weights 14 to provide a force for moving the clamping device 8 between the first stop 11 and the second stop 12.By converting the applied forces, a clear prediction can also be made about the expected elongation properties of the animal hide 2. This simplifies the selection of animal hides 2 for subsequent cutting, when different animal hides 2 are needed to produce cut pieces that, as a assembled set consisting of several individual parts, must exhibit the same elongation values. Furthermore, as in . Figure 8As shown, hydraulic cylinders 18 connected to the tensioning elements 6 can be used instead of or in addition to the tensioning weights 14. These cylinders allow for the determination of both the applied force and the displacement, thus enabling the calculation of the tensile stress applied to the animal hide 2. Using hydraulic cylinders 18 instead of or in addition to the tensioning weights 2 also eliminates the need for the first stop 11 and the second stop 12, and allows the longitudinal expansion or contraction of the hydraulic cylinders 18 to be determined directly at the respective hydraulic cylinder 18 or by means of a separate control or measuring device. Alternatively, the first stop 11 and the second stop 12 can also be provided on the device 1 with hydraulic cylinders 18. The pressure within the hydraulic cylinders 18 can also be used as an indicator of the elasticity of the animal hide 2.Furthermore, the hydraulic cylinders can include 18 locking valves, which fix a certain length of the hydraulic cylinders. Alternatively, all traction elements 6 can be connected to at least one hydraulic cylinder 18. Furthermore, as in . Figure 8 Each traction element 6 is shown to be connected to its own hydraulic cylinder 18 for applying tensile stress to the traction element 6. In addition to these, a hydraulic cylinder 18 can be connected to the traction element 6. Figure 8 An additional, central main hydraulic cylinder (not shown) is provided, which is connected to the hydraulic cylinders 18, and applies a central force to all the traction elements 6 simultaneously after a preferably uniform tensioning of the traction elements 6 by means of the hydraulic cylinders 18 assigned to the individual traction elements 6.

[0024] The absorption medium is preferably as described in Figure 5The circular plate is depicted as being essentially circular. According to a preferred embodiment, the circular plate is arranged essentially parallel to the support surface 3. Furthermore, the support surface 3 is preferably essentially circular. This ensures uniform tension of the tensioning elements 6. According to alternative embodiments, the support surface 3 can be, as shown in Figure 9 depicted, also square or essentially square with rounded or chamfered corners.

[0025] As in Figure 1 and Figure 2 The device shown comprises 1 deflecting means 15 for deflecting the traction means 6. Figure 6 Figure 1 shows the course of the tensioning elements 6 and the tensioning device 8 of the device according to the invention in the preferred embodiment. The deflecting elements 15 guide the tensioning elements 6 along the path shown in Figure 1. Figure 6The depicted path runs from the support surface 3 to the clamping device 8. Preferably, the deflection means 15 are arranged at an edge region of the support surface 3. The tension means 6 are deflected several times by means of the deflection means 15 in order to transfer the tensile stress from the clamping device 8 to the animal skin 2.

[0026] Preferably, the device 1 comprises a Figure 2 and in Figure 7 The support block 16 is shown in detail. According to the preferred embodiment of the device 1 according to the invention, the support surface 2, the tensioning elements 6 and the clamping device 8 are connected to the support block 16. Furthermore, the first stop 11, the second stop 12, the deflection elements 15 and the cables 13 can be connected to the support block 16.

[0027] According to a, in Figure 9In the illustrated alternative embodiment of the device 1 according to the invention, the support surface 3 comprises recesses 17, wherein the tensile elements 6 are at least partially received in the recesses 17. This means that the tensile elements 6 and the support surface 3 essentially form a plane, which has the advantage that the animal hide 2 is not lifted from the support surface 3 when tensile stress is applied. This results in improved detection of areas with inhomogeneous tension or tensile strength in the animal hide 2. Preferably, the deflection elements 15 and / or the tensile clamps 7 are also at least partially received in the recesses.The recesses 17 are advantageously designed as guide grooves, thereby achieving a reproducible clamping, or a clamping angle, that is essentially the same for each animal skin 2, and an essentially the same configuration of the tensile stress lines 9 relative to each other.

Claims

1. Device (1) for stretching animal hide (2), comprising a support surface (3) for supporting the animal hide (2), a first pair (4), and a second pair (5) of tensioning elements (6) attachable to substantially opposite edge regions of the animal hide (2), wherein the tensioning elements (6) are connected to a tensioning device (8) for applying a tensile stress to the tensioning elements (6), and each pair (4, 5) of tensioning elements (6) forms a tension line (9) in the animal hide (2) when subjected to the tensile stress. characterized by the fact that the tensile stress line (9) of the first pair (4) forms an acute angle with the tensile stress line (9) of the second pair (5).

2. Device (1) according to claim 1, characterized by the fact thatthe device (1) comprises at least one further pair of traction elements (6) that can be attached to substantially opposite edge regions of the animal skin (2), wherein the line of tensile stress (9) of each pair of traction elements (6) forms an acute angle with the line of tensile stress (9) of an adjacent pair of traction elements (6).

3. Device (1) according to one of claims 1 or 2, characterized by the fact that The tensile stress lines (9) of the pairs (4, 5) on the tensile elements (6) intersect essentially in a central area (10) of the animal skin (2).

4. Device (1) according to any one of claims 1 to 3, characterized by the fact thatthe device (1) comprises a first stop (11) and a second stop (12), and the clamping device (8) is movably mounted between the first stop (11) and the second stop (12), wherein the tensioning elements (6) are substantially free of tensile stress when the clamping device (8) is in contact with the first stop (11), and are subjected to tensile stress when the clamping device (8) is in contact with the second stop (12).

5. Device (1) according to claim 4, characterized by the fact that the distance between the first stop (11) and the second stop (12) is variable.

6. Device (1) according to one of claims 4 or 5, characterized by the fact that the clamping device (8) is connected to a cable pull (13), wherein the cable pull (13) is designed to move the clamping device (8) between the first stop (11) and the second stop (12).

7. Device (1) according to any one of claims 1 to 6 characterized by the fact thatthe clamping device (8) comprises at least one receiving means for receiving clamping weights (14).

8. Device (1) according to claim 7, characterized by the fact that The receiving medium is designed as an essentially circular plate.

9. Device (1) according to claim 8, characterized by the fact that the plate is arranged essentially parallel to the support surface (3).

10. Device (1) according to any one of claims 1 to 9, characterized by the fact that the traction means (6) include self-locking traction clamps (7) for attaching the traction means (6) to the animal skin (2).

11. Device (1) according to any one of claims 1 to 10, characterized by the fact that the device (1) comprises deflecting means (15) for deflecting the traction means (6).

12. Device (1) according to claim 11, characterized by the fact that the deflection means (15) are arranged at an edge area of ​​the support surface (3).

13. Device (1) according to claim 6, characterized by the fact thatthe tensioning device (8) is connected to two cable pulls (13).

14. Device (1) according to any one of claims 1 to 13, characterized by the fact that the device (1) comprises a support block (16) wherein the support surface (3), the tensioning means (6) and the clamping device (8) are connected to the support block (16).

15. Device (1) according to any one of claims 1 to 14, characterized by the fact that the bearing surface (3) is essentially circular.

16. Device (1) according to any one of claims 1 to 15, characterized by the fact that the support surface (3) comprises recesses (17), wherein the traction means (6), the traction clamps (7) and / or the deflection means (15) are at least partially accommodated in the recesses (17).

17. Device (1) according to any one of claims 1 to 16, characterized by the fact that the traction means (6) are connected to at least one hydraulic cylinder (18).