Gripper device and stretching device

Abstract

To provide a reliable gripper device that performs contactless opening (and contactless closing) even at high travel speed.SOLUTION: A gripper device comprises a base body, a gripping jaw, and at least one operation lever. The operation lever is installed rotatably on the base body around a pivot axis (122). A movable gripping jaw installed on a first end portion of the operation lever grips a belt-like material in cooperation with the gripping jaw on a gripping position. In addition, the operation lever is provided with a neck portion that extends from the pivot axis to a head portion (128), and the head portion that forms a second end portion of the operation lever. The head portion has a top length (LK) at least 50% longer than a minimum length (LH) of the neck portion measured in a travel direction (R) of the gripper device.SELECTED DRAWING: Figure 7A

Description

[Technical Field]

[0001] The present invention relates to a magnetic release gripping device for a stretching apparatus, a stretching apparatus equipped with a magnetic release gripping device and at least one corresponding gripping tool. [Background technology]

[0002] Stretching devices are used, in particular, for the production of plastic thin films. A strip of material to be stretched, such as a typical plastic thin film, is gripped by a number of gripping devices and moved through the stretching device. The gripping devices are typically guided and movably arranged on circular guide rails. Related devices included in the gripping devices include a conveying device, in particular including a guide rail and a drive unit. In either case, the guide rail is fully or partially arranged within a heating furnace. This allows the temperature of the strip of material (in particular the plastic thin film) to be controlled (in particular for heating or maintaining at a desired temperature) before and / or during the gripping process.

[0003] The circulating guide rails guide the gripping devices along the movement path. The drives of the gripping devices can operate the gripping devices centrally or drive the gripping devices individually. In contrast to the central drive, the gripping devices can be provided with chain links and / or be drivingly connected to one another via chain links, so as to centrally drive the corresponding chain links of the drives.

[0004] The gripping devices of the gripping device must be moved from an open position to a closed (gripping) position to grip or move the web of material. The gripping of the web of material by the gripping devices occurs in the inlet area of ​​the gripping device. The gripping devices of the gripping device typically have at least two gripping surfaces arranged substantially opposite each other to grip the side edges of the web of material. By actuating a lever (also called an operating rod), the opposing gripping surfaces of the gripping devices can be moved relative to each other in the gripping position.

[0005] The operating rod can also be used to release the stretched web of material from the gripping device. In particular, the gripping device must be released after the stretching process has completed. This release of the stretched film typically occurs after the stretching device has passed through a heating or cooling zone and the gripping device has guided the stretched film. After the gripping device is returned to its release position on the guide rail, the gripping device must again grip the web of material and move the gripping device through the stretching zone of the gripping device again. It will be appreciated that the gripping device must be released before a new web of material can be gripped.

[0006] The gripping device can be moved to the open and closed positions in a generally contactless manner, avoiding wear and tear on the gripping device. For example, magnetic release and closing devices are known. Mechanical forced release or closing devices can also be provided to reliably release or close the gripping device. The forced release / closure device is provided with a stop that prevents the gripping device from fully releasing or closing when the gripping device is guided past it.

[0007] However, the actuation of stops and the sudden release or closing of the gripping devices requires high mechanical stresses which significantly reduce the operational life of the gripping devices. For example, if one part of the gripping device, such as the operating rod or other part of the gripping mechanism, breaks due to impact stresses, other parts of the stretching device may also be damaged and / or result in downtime and production losses.

[0008] The current trend in drawing devices is to increase production speeds, however the release speeds of known magnetic non-contact release devices are decreasing in relation to the increased production speeds and the associated high movement speeds of the gripping devices (this also applies to closing devices).

[0009] When driving stretching devices, especially at very high production speeds (e.g., >500 m / min) as used in the production of polyethylene terephthalate, polyethylene, polypropylene and polyamide thin films (with corresponding high movement speeds of the gripping devices), known gripping devices are unable to provide a contactless release / closure with sufficient reliability and therefore have to resort to harmful forced release (with corresponding forced closure). Summary of the Invention [Problem to be solved by the invention]

[0010] The object of the present invention is to provide a gripping device that is reliable and provides contactless release (and contactless closing) even at high moving speeds. This object is achieved by a gripping device and a stretching device as set forth in the independent claims of the present invention. The characteristics of the present invention are also set forth in the independent claims and in the following description.

[0011] In particular, the object of the present invention is solved by a gripping device for a stretching device. The gripping device can be intended as a transverse orienter or a co-stretching device. [Means for solving the problem]

[0012] A transverse orienter is a stretching device that stretches a web of material traveling in a direction generally perpendicular to the direction of travel of the web of material, particularly a transverse direction. The transverse orienter is provided with a pair of guide rails in a transverse stretching region where the spacing between the pair of guide rails increases in the direction of travel. When stretching in the machine direction is desired, the machine direction orienter can be located upstream or downstream of the transverse orienter.

[0013] A simultaneous stretching device is a stretching device that simultaneously stretches in both the machine direction and the transverse direction. For example, simultaneous stretching can be achieved by rapidly accelerating multiple grippers separated by different guide rails. As a result, a strip of material can be stretched in the machine direction, and simultaneously stretched in the transverse direction by arranging guide rails with increasing spacing in the conveying direction.

[0014] The gripping device is guided on a guide rail of the stretching device, and for this purpose the gripping device comprises at least one guide piece, in particular a slide piece or a guide roller, which is arranged on the base body of the gripping device and guides the gripping device on the guide rail.

[0015] The gripping device can also be configured with a base body connected to a chain link. The chain link can form part of a drive chain. Likewise, the gripping device comprises at least one chain link to which the base body is connected in a fixed manner. In this way, multiple gripping devices can be connected to a chain and driven by a central drive. Alternatively, each gripping device can be driven individually. For this purpose, the guide rail - at least in several sections - can be designed with a linear motor or at least one linear motor can be assigned to the guide rail.

[0016] In addition to the base body, the gripping device of the present invention comprises gripping jaws and at least one operating rod. The gripping jaws can be integral with the base body (directly or indirectly) or connected to the base body. The gripping jaws can be formed as fixed or movable gripping jaws. The operating rod (also called gripping lever) can be arranged rotatably on the base body about a pivot. For example, the operating rod has a through-hole for mounting the pivot. Alternatively, the pivot (or pivot portion) can be provided on or attached to the operating rod.

[0017] A control rod that rotates from a gripping position to a release position is attached to the base. The control rod is thus pivoted in the opposite direction of rotation from the release position to the gripping position. The control rod has a movable gripping jaw at a first end. The movable gripping jaw and the control rod are actuated together to the gripping position to grip the web-shaped material. In particular, the web-shaped material, e.g., a thin resin film, can be gripped and fixed between the gripping jaw and the movable gripping jaw.

[0018] The gripping jaws and / or the movable gripping jaw can be formed to increase the gripping force. For example, a pair of gripping jaws can be provided with ribs and / or teeth. Similarly, multiple gripping jaws can be formed at approximately equal angles. The actuating rod also includes a neck and a head. The neck extends from a pivot to the head, and the head forms the second end of the operating rod. In particular, the pivot is provided between the gripping jaws and the head. Furthermore, the rim (first end) of the operating rod extends from the pivot to the movable gripping jaw. The rim and the neck form an angle of 100° to 170° or 120° to 150° and meet (are connected) at the pivot.

[0019] The head must be the minimum length of the neck L H At least 50% longer than L K The top of the head L K and the minimum length of the neck L H is measured in the direction of movement of the gripping device (on the guide rail). K is the length of the edge of the head that is disposed approximately parallel to the pivot axis. The minimum length of the neck, L H is measured at the area of ​​least linear extension of the neck, which can also be seen as the area where the neck is adjacent to the head.

[0020] In the embodiment of the present invention, the top side L of the head K is the minimum length of the neck L H Optionally, the top of the head L K is the minimum length of the neck L H Up to 120%, up to 110% or up to 100% longer.

[0021] Due to the long head shape, the magnetic force available for opening / closing the gripping device is significantly increased. Depending on the design, this can be increased by up to 25% or even 35%. This allows the rod to be reliably opened at high travel speeds of >500 m / min, >600 m / min, or >700 m / min. Furthermore, the time interval during which the magnet of the opening device exerts its influence on the rod as it is guided past the magnet is extended. This results in a very reliable opening of the rod, and the same applies to the closing device, as it rotates the rod from the open position to the gripping position.

[0022] The magnetic force can be increased through a shape called the operating angle φ. The operating angle φ is the angle between a line parallel to the pivot axis and the side edge of the head. For example, the operating angle φ can range from 0° to 80°, 30° to 75°, or 45° to 65°. The achievable increase in magnetic force is in the range of 45° to 65° at most. When the magnetic operating angle φ exceeds 65°, the magnetic force increase reaches a limit value. Rapid movement speed can be achieved through the increase in magnetic force.

[0023] In an embodiment of the present invention, the gripping device is provided with multiple (e.g., two or three) operating rods. In this respect, the operating rods can be preferably arranged adjacent to one another in the movement direction R of the gripping device. This allows the gripping device to grip the web-like material at multiple gripping points, thereby increasing the holding force acting in the lateral direction of the web-like material.

[0024] For example, the minimum length L of the neck of the operating rod in the head direction of at least a certain region H The tapered portion can reduce the weight of the operating rod and determine the location of the center of gravity. In principle, it is preferable to make the movable operating rod as light as possible to provide the lowest possible inertial force with the lowest mass. This simplifies the opening and closing operations. Furthermore, the center of gravity of the operating rod can be aligned with the pivot axis or at least located as close to the pivot axis as possible. As a result, only a small force is required for the opening or closing operation, simplifying the opening or closing operation.

[0025] In another embodiment of the invention, grooves or through-holes can be provided in the head to reduce the weight of the operating rod and / or change the position of the center of gravity of the operating rod. For example, grooves can be provided in the head to provide a depth corresponding to at least 30%, at least 50%, or at least 70% of the width of the head. The linear extension of the head (length L K The width of the head is measured in a direction perpendicular to the direction of extension of the neck.

[0026] The through-hole or groove in the head can have an upper edge extending substantially parallel to the upper edge of the head. The distance between the upper edge of the groove or through-hole and the upper edge of the head can be set to, for example, 2 mm to 6 mm, 2.5 mm to 5 mm, or 3 mm to 4 mm, so that the ratio of the increase in inertial force to the increase in magnetic force can be optimized within the range.

[0027] In the embodiment of the present invention, the top side L of the head K The length ranges from 20 mm to 60 mm, 35 mm to 55 mm, or 45 mm to 50 mm.

[0028] In an embodiment of the present invention, a larger width B K In particular, the width B of the head K The width ranges from 2 mm to 6 mm, 3 mm to 5.5 mm, or 4 mm to 5 mm. A larger width does not result in a sufficient increase in magnetic force.

[0029] In the embodiment of the present invention, the head of the operating rod has a height H in the range of 10 mm to 30 mm, 15 mm to 25 mm, or 17 mm to 21 mm. K The height of the operating rod head is H K is measured along the main length of the neck (from the pivot to the head).

[0030] In another embodiment of the present invention, the operating rod is provided with a stop piece of a biasing means. For example, the biasing means is a compression spring. The biasing means, which constitutes part of the gripping device according to this example, is arranged between the stop piece and the base body. This biases the operating rod to the gripping position, further increasing the gripping force and preventing the operating rod from being accidentally opened.

[0031] In particular, a stop piece can be arranged in the area between the movable gripping jaw and the pivot, or the pivot can be arranged in the area between the movable gripping jaw and the stop piece, which allows the gripping device of the invention to generate a high gripping force and ensures good reliability when opening the operating rod.

[0032] In an embodiment of the invention, the head can be magnetized more strongly than the neck. Magnetization can be achieved by a corresponding heat treatment, in particular heat hardening, which imparts a martensitic structure to at least the head (region). Additionally or alternatively, the head has a low carbon content, which allows for a stronger magnetization or magnetization. As a result of magnetizing the head, the magnetic force available for opening / closing the gripping device can be further increased. This therefore has the advantage that the operating rod can be operated without losses in the reliable opening / closing action, even at high movement speeds. In an embodiment of the invention, the head, which is provided with at least one magnet, further increases the magnetic force available for the opening / closing action of the operating rod.

[0033] The object of the present invention can be achieved by a stretching device, in particular a transverse orienter or a simultaneous stretching device. The stretching device comprises at least one guide rail and at least one gripping device as described above. In this case, the gripping device is guided on the guide rail. The movement speed of the gripping device, driven by the stretching device while circulating on the guide rail, is at least 500 m / min, at least 600 m / min or at least 700 m / min.

[0034] The stretching device is also provided with at least one magnetic release device that opens the gripping device (or the operating rod) without contact after the stretching device has passed through the stretching region. The stretching device is also provided with at least one magnetic closing device that closes the gripping device (or the operating rod) without contact after the stretching device has passed through the stretching region. This allows the web-shaped material to be gripped.

[0035] At least one magnet is provided on the magnetic release device and in the region of the at least one guide rail, which rotates the operating rod of the gripping device into an open position when the gripping device is guided past the magnetic release device.

[0036] At least one magnet is provided on the magnetic closing device and in the region of the at least one guide rail, which rotates the operating rod of the gripping device into the gripping position when the gripping device is guided past the magnetic closing device.

[0037] In an embodiment of the present invention, at least one magnet is measured in the direction of movement of the gripping device and the condition: 0.8L K <= L M <=1.2L K The length L that corresponds to M This allows for the application of a strong magnetic force to ensure reliable rotation of the operating rod to the open and closed positions.

[0038] In the embodiment of the present invention, the top side L of the head K is the length of the magnet L M Optionally, the top of the head L is at least 30%, at least 40%, or at least 50% longer than the top of the head L K is the length of the magnet L M at least 50%, at least 40% or at least 30% less than

[0039] Furthermore, the distance between two adjacent magnets of the opening device (corresponding to the closing device) is (L M -L K ) / 2. For example, the spacing between two adjacent magnets is <=4 mm, <=3 mm, or <=2.5 mm.

[0040] This allows a substantially constant magnetic force to be applied to the operating rod over the entire length of the opening or closing device, further enhancing the reliability of the opening / closing operation and thereby avoiding the problem of an operating rod that has already been partially opened (or partially closed) unexpectedly returning to the gripping position (or open position).

[0041] In an embodiment of the present invention, the air gap formed between the at least one magnet and the head of the operating rod is in the range of 1.5 mm to 5 mm, 2 mm to 4 mm, or 2.5 mm to 3.5 mm, thereby achieving a strong magnetic force.

[0042] The stretching device is also provided with at least one reverse magnet 38 in the area of ​​the magnetic release device (magnetic closing device) that presses (biases) at least one gripping device toward the guide rail, thereby preventing the gripping device from floating away from the guide rail by the magnetic force acting via the magnetic release device (or magnetic closing device) of the gripping device. [Brief explanation of the drawings]

[0043] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. [Figure 1] FIG. 1 is a plan view showing a first embodiment of a stretching device equipped with a gripping device of the present invention. [Figure 2] FIG. 10 is a plan view showing a second embodiment of a stretching device equipped with a gripping device of the present invention. [Figure 3] 1 is a cross-sectional view of a gripping device according to the present invention; [Figure 4] 1 is a perspective view of an operating rod used in the gripping device of the present invention; [Figure 5] 1 is a perspective view of a different operating rod for use with the gripping device of the present invention; [Figure 6] FIG. 10 is a perspective view of yet another operating rod used in the gripping device of the present invention. [Figure 7A] Plan view of the operating rod with the opening / closing magnet [Figure 7B] Graph showing the magnetic force of the magnet along the axis of the operating rod [Figure 8] Graph showing the change in magnetic force of the magnet with respect to the tilt angle of the operating rod DETAILED DESCRIPTION OF THE INVENTION

[0044] 1 shows a plan view of a drawing apparatus 10 including a furnace 14 and a pair of drives 16. The drives 16 are arranged in mirror symmetry with respect to an axis of symmetry S of the drawing apparatus 10 and extend at least partially within the furnace 14. The drives 16 are located outside the furnace 14 at an entrance region 18 of the drawing apparatus 10 where the web of material is introduced into the furnace 14 and at an exit region 20 where the web of material is removed from the furnace 14.

[0045] In addition to the entrance region 18 and the exit region 20, the illustrated stretching apparatus 10 further includes at least three other regions 22, 24, and 26. The three regions 22, 24, and 26 are adjacently positioned along the general direction of movement of the stretching apparatus 10, i.e., the direction of pulling of the web of material, with the first region 22 adjacent to the entrance region 18, followed by the second region, the third region, and finally the exit region 20.

[0046] In a first region 22, also referred to as a preheating region of the stretching apparatus 10 adjacent the entrance region 18, the pair of drivers 16 are spaced apart by a first distance. In a second region 24, also referred to as a stretching region, the distance between the pair of drivers 16 increases until the beginning of a third region 26, also referred to as a heat treatment region, where the distance between the pair of drivers 16 is increased to a second distance.

[0047] Guide rails 40, 42 for guiding the multiple gripping devices 100 are provided in a known manner on each of the pair of drive units 16. Each drive unit 16 is driven to move the gripping devices 100 along the guide rails 40, 42. Although only two gripping devices 100 are symbolically shown per drive unit 16 in Figures 1 and 2, the stretching apparatus 10 includes multiple gripping devices 100.

[0048] The guide rails 40, 42 of each drive unit 16 define a closed circular path from the entry area 18 to the exit area and from the exit area 20 to the entry area 18. The guide rail sections defining the forward movement path are laid in the intended direction of movement of the gripping device 100 within the furnace 14 between the entry area 18 and the exit area 20.

[0049] In the illustrated embodiment, the guide rail section, which is arranged in the normal operating direction from the exit area 20 to the entrance area 18, is formed as a return path within the furnace 14. The embodiment shown in Figure 2 illustrates an example in which the return path of the guide rail section is arranged outside the furnace 14.

[0050] The stretching device 10 is operated by feeding a strip of material to be stretched, such as a thin resin film, into the inlet region 18 of the stretching device 10 in the pulling direction R. For this purpose, both side edges of the strip of material 50 are gripped by gripping devices 100 and pulled in the pulling direction R by a pair of drive devices 16. Furthermore, both side edges of the strip of material 50 held by the corresponding gripping devices 100 are moved along the guide rails 40, 42 of the drive devices 16 together with the movement of the gripping devices 100.

[0051] At the entrance region 18, the web 50 has a width perpendicular to the pulling direction R (entrance width) that corresponds substantially to the first spacing between the drivers 16. The web 50 is guided through the first region 22 and heated there. Thereafter, in the second or stretching region 24, the spacing between the drivers 16 continuously increases, so that the web 50 is stretched in the transverse direction. At the end of the second region 24, the web 50 has a second width A (exit width).

[0052] After the stretching process is complete, the web material 50 passes through the third region 26, where the internal stress of the web material 50 is relieved by heating before the web material 50 is removed from the gripping device 100 in the exit region 20, where the web material 50 having the width A is removed from the stretching device 10. For example, the stretching device 10 may be a thin film expansion stretching device or a transverse orienter (abbreviated as "TDO"). The stretching device 10 may also be a simultaneous stretching device that stretches the web material 50 in the second region 24 not only in the direction transverse to the tensile direction R but also in the tensile direction R.

[0053] During processing of the web-shaped material 50, in the second region 24, i.e., the stretching region, the gripping device 100 is primarily subjected to a large tensile force in the tensile direction. The tensile direction is predominantly the main direction P of the gripping device 100, and forces transverse to the main direction P are very small. The stretching device 10 also includes at least one magnetic release device 30 that contactlessly (by magnetic force) releases the gripping device 100 after passing through the stretching device or the internal stress relaxation region. The stretching device 10 also includes at least one magnetic closing device 31 that contactlessly closes the gripping device 100 to grip the web-shaped material.

[0054] 3 shows a cross-sectional view of a gripping device 100 according to the present invention. The gripping device 100 comprises a base 110 and an operating rod 120. The operating rod 120 is mounted on the base 110 around a pivot 122 so as to be rotatable (angle α) from a gripping position (shown by a dotted line) to an open position (shown by a solid line).

[0055] Furthermore, the gripping device 100 includes a guide piece 140 used for the gripping device 100, which is guided by the guide rail 40. A gripping jaw 114, which is additionally provided on the base 110 (or integrally attached to the base 110), cooperates with a movable gripping jaw 124 that is part of the operating rod 120 to grip the strip material 50. The strip material 50 in the gripping position is fixed between both gripping jaws 114 and 124.

[0056] Further, the operating rod 120 includes a neck portion 126 and a head portion 128. The neck portion 126 extends from the pivot 122 to the head portion 128. To open and close the operating rod 120 relative to the web 50, at least one magnet 36 is provided which actuates the magnetic opening device 30 and the magnetic closing device 31. Depending on the arrangement of the magnet 36, the operating rod 120, and particularly the head portion 128, may be provided with a magnetic force F that forces the operating rod 120 to move into either the gripping position (shown in FIG. 3) or the open position. M acts on the operating rod 120. A counter magnet 38 can be provided which pulls the gripping device 100 onto the guide rail 40, preventing the magnet 36 from lifting the gripping device 100 off the guide rail 40.

[0057] Furthermore, a stop piece 125 (for example, in the form of a stop protrusion) can be provided on the operating rod 120, and a biasing means can be attached using the stop piece 125. The biasing means, particularly a compression spring, that biases the operating rod 120 to the gripping position can be provided between the stop piece 125 and the base material 110.

[0058] 4 shows a perspective view of a conventional operating rod. A known operating rod 120 that rotates from an open position to a gripping position is mounted around a pivot 122. However, in the present invention, a neck and a head are not provided, and this configuration has the drawback that the operating rod 120 cannot be quickly moved between the open and closed positions by a magnetic release device.

[0059] 5 shows a perspective view of the operating rod 120 of the gripping device 100 of the present invention. The operating rod 120 has a neck 126 extending from a pivot 122 to a head. At a first end 121 of the operating rod 120, the operating rod 120 has a movable gripping jaw 124, and at an opposite second end 123, a head 128 is provided.

[0060] The head 128 is the minimum length L of the neck 126. H At least 50% longer than L K (measured in the direction of movement R of the gripping device 100). The neck 126 of the illustrated operating rod 120 is tapered toward the head 128, and the tip is widened again. In the illustrated example, the top side L of the head 128 is K The length is in the range of 20 mm to 60 mm, 35 mm to 55 mm, and particularly 45 mm to 50 mm.

[0061] Additionally, the head 128 has a height H measured along the major length of the neck 126 that ranges from 10 mm to 30 mm, 15 mm to 25 mm, or 17 mm to 21 mm. K This geometrical dimension allows the magnetic force F M is significantly increased, resulting in consistent and reliable ultrafast opening / closing of operating rod 120. Head 128 optionally includes grooves 129 or through-holes as shown in FIG.

[0062] The stop piece 125 shown in FIG. 5 is provided in the region between the pivot 122 and the head 128, but the stop piece 125 can also be provided between the movable gripping jaw 124 and the pivot 122 as shown in FIG.

[0063] 6 shows a perspective view of another operating rod 120 of the gripping device 100 of the present invention. In this figure, the same parts as those in other figures are given the same reference numerals, and duplicated explanations will be omitted. In the operating rod 120 shown in FIG. 6, the head portion 128 has a width B that is longer than the neck portion 126. K The head 128 has an arbitrary width B K The range is 2 mm to 6 mm, 3 mm to 5.5 mm, or 4 mm to 5 mm.

[0064] The groove 129 connected to the head 128 has a width B of the head 128. K The groove 129 has a depth that reaches at least 30%, at least 50%, or at least 70% of the width of the groove 129. The groove 129 also has an upper edge that is substantially parallel to the top edge of the head 128. The upper end of the head 128 is formed thick. Similarly, thicker regions are formed laterally of the groove 129.

[0065] The distance between the groove 129 and the upper edge of the head 128 is, for example, in the range of 2 mm to 6 mm, 2.5 mm to 5 mm, or 3 mm to 4 mm. The linear extension of the lateral thickness region (in the conveying direction R) is in the range of 2 mm to 6 mm, 2.5 mm to 5 mm, or 3 mm to 4 mm.

[0066] 7A shows the operating rod 120 of FIG. 5 being guided in the conveying direction R past the opening devices or magnets 32, 34, 36, where the magnetic force F M acts on the head 128 of the operating rod 120. The operating angle (φ) of the head 128 is the angle formed by the side edge of the head 128 that is parallel to the pivot 122. For example, the operating angle (φ) of the head 128 is in the range of 0° to 80°, 30° to 75°, or 45° to 65°.

[0067] FIG. 7B shows that the magnetic force F M 10 is a graph showing the amount of change in magnetic force F acting on the operating rod according to the present invention. M The magnetic force F acting on a typical conventional operating rod is shown by the solid line. M is shown by the dotted line. First, the magnetic force was increased by 25% to 35% compared to the conventional method. Furthermore, the magnetic force transition along the extension line x in the conveying direction R is stable without any partial inflection points. The present invention achieves both reliable opening and closing operations of the operating rod.

[0068] Figure 8 shows the magnetic force F as a function of the angular position α. M 10 is a graph showing the change in magnetic force F acting on the operating rod according to the present invention. M is shown by a solid line, and the magnetic force F acting on a typical conventional operating rod is shown by a solid line. Mis shown by the dotted line. Again, it can be seen that a significantly strong magnetic force acts on the pivotally mounted operating rod (10° deflection angle).

[0069] It will be appreciated that the gripping and stretching devices of the present invention can be operated at high speeds while still achieving reliable, contactless opening / closing of the gripping devices. [Explanation of symbols]

[0070] 10... Drawing device, 14... Heating furnace, 16... Drive device, 18... Inlet area, 20... Outlet area, 22... Area (preheating area), 24... Area (stretching area), 26... Area (heat treatment area), 30... Opening device, 31... Closing device, 32, 34, 36... Magnet. 38 Reverse magnet, 40, 42 Guide rail, 50 Strip material, 100 Gripping device, 110 Base, 114 Gripping jaw, 120 Operating rod, 121 First end, 122 Pivot, 124 Movable gripping jaw, 125 Stopping member, 126...Neck, 128...Head, 129...Groove, 140 Guide piece, R Strip material conveying direction, P Lateral force, A Exit width, E Entrance width, S Target surface, L K Head length, L H Neck length, L M Magnet length, B K ·Head width, H K Head height, F M ·Magnetic force (width direction),

Claims

1. A gripping device (100) for a stretching device (10), such as a transverse orienter or a simultaneous stretching device, The gripping device (100) is guided on a guide rail (40), The gripping device (100) comprises a base (110), gripping jaws (114), and at least one operating rod (120); The operating rod (120) is rotatably disposed on the base (110) about a pivot (122) between a grip position and an open position; A movable gripping jaw (124) provided at a first end (121) of the operating rod (120) grips the elongated material (50) in cooperation with the corresponding gripping jaw (114) at the gripping position; The operating rod (120) has a neck portion (126) and a head portion (128), The neck (126) of the operating rod (120) extends from the pivot (122) to a head (128), the head (128) forming the second end (123) of the operating rod (120); The head (128) of the operating rod (120) has a head length (L) measured in the direction of movement (R) of the gripping device (100). K ) and the head (128) has a head length (L K ) is the minimum length (L) of the neck (126) measured in the direction of movement of the base (110). H ) is at least 50% longer than the gripping device (100) for the stretching device (10).

2. 2. The gripping device (100) for a stretching device (10) according to claim 1, wherein the gripping device (100) comprises a plurality of operating rods (120) arranged adjacent to each other in the moving direction of the gripping device (100).

3. 2. The gripping device (100) for a stretching device (10) according to claim 1, wherein the length of the neck (126) of the operating rod (120) is tapered toward the head (128) in at least a certain region.

4. The head (128) of the operating rod (120) has a groove (129) or a through hole. The groove (129) in the head (128) is K 2. The gripping device (100) for a stretching device (10) according to claim 1, optionally having a depth reaching at least 30%, at least 50%, or at least 70% of the width of the stretching device (10).

5. the groove (129) or through-hole in the head (128) of the operating rod (120) has a top end that is substantially parallel to the top end of the head (128); 5. The gripping device (100) for a drawing apparatus (10) according to claim 4, wherein the distance between the top end of the groove (129) or through-hole in the head (128) and the top end of the head (128) is optionally in the range of 2 mm to 6 mm, 2.5 mm to 5 mm, or 3 mm to 4 mm.

6. The head length (L) of the head (128) of the operating rod (120) K ) is in the range of 20 mm to 60 mm, 35 mm to 55 mm, or 45 mm to 50 mm, and / or 2. The gripping device (100) for a stretching device (10) according to claim 1, wherein the operating angle (φ) of the head (128) of the operating rod (120) is in the range of 0° to 80°, 30° to 75°, or 45° to 65°.

7. The head portion (128) of the operating rod (120) has a width (B) greater than that of the neck portion (126). K ) and The width of the head (128) of the operating rod (120) (B K 2. The gripping device (100) for a drawing apparatus (10) according to claim 1, wherein the thickness of the drawing apparatus (10) is optionally in the range of 2 mm to 6 mm, 3 mm to 5.5 mm, or 4 mm to 5 mm.

8. The head 128 of the operating rod 120 has a height (H) measured in the main direction of extension of the head 128 in the range of 10 mm to 30 mm, 15 mm to 25 mm, or 17 mm to 21 mm. K 2. The gripping device (100) for a stretching device (10) according to claim 1, comprising:

9. The gripping device (100) further comprises at least one guide piece (140) disposed on the base (110) for guiding the gripping device (100) on the guide rail (40); 2. The gripping device (100) for a drawing device (10) according to claim 1, wherein at least one guide piece (140) comprises a slider or a guide roller.

10. The substrate (110) is connected to at least one chain link; and / or 2. The gripping device (100) for a drawing apparatus (10) according to claim 1, wherein the gripping device (100) comprises at least one chain link fixedly connected to the base body (110).

11. The operating rod (120) is provided with a stop piece (125) of the biasing means, 2. The gripping device (100) for a stretching device (10) according to claim 1, wherein a biasing means such as a compression spring arranged between the stop piece (125) and the base (110) applies a pressing force to the operating rod (120) in the gripping position.

12. The stop piece (125) is located in the area between the movable gripping jaw (124) and the pivot (122), or 12. The gripping device (100) for a drawing device (10) according to claim 11, wherein the pivot (122) is arranged in the area between the movable gripping jaw (124) and the stop piece (125).

13. the head portion (128) is more strongly magnetized than the neck portion (126), and / or 2. The gripping device (100) for a stretching apparatus (10) according to claim 1, wherein the head (128) comprises at least one magnet.

14. 2. The gripping device (100) for a drawing apparatus (10) according to claim 1, wherein the operating rod (120) is made of steel, and the head (128) has a lower carbon content than the neck (126).

15. 2. The gripping device (100) for a drawing apparatus (10) according to claim 1, wherein the head (128) is heat treated.

16. 16. The gripping device (100) for a drawing device (10) according to claim 15, wherein the head (128) is hardened.

17. at least one guide rail (40, 42) according to any one of claims 1 to 15 and at least one gripping device (100), A stretching device characterized in that the gripping device (100) is guided by guide rails (40, 42).

18. 17. The stretching device (10) of claim 16, wherein the stretching device (10) is a transverse orienter or a co-stretching device.

19. The stretching device (10) comprises at least one magnetic release device (30) and / or at least one magnetic closing device (31); The magnetic release device (30) includes at least one magnet (32, 34, 36) disposed in the region of at least one guide rail (40, 42) and configured to rotate the operating rod (120) of the gripping device (100) to a release position when the gripping device (100) is guided through the magnetic release device (30); 17. The drawing device (10) according to claim 16, wherein the magnetic closing device (31) comprises at least one magnet (32, 34, 36) arranged in the region of the at least one guide rail (40, 42) and adapted to rotate the operating rod (120) of the gripping device (100) into the gripping position when the gripping device (100) is guided through the magnetic closing device (31).

20. The head length of the head (128) of the operating rod (120) is (L K ), the at least one magnet satisfies the following conditions measured in the direction of movement (R) of the gripping device (100): 0.8L K <= L M <=1.2L K The length (L M 20. The drawing device (10) of claim 19, comprising:

21. The spacing between two adjacent magnets (32, 34, 36) is (L M -L K 20. The drawing device (10) of claim 19, wherein the drawing rate is equal to or less than 1 / 2.

22. 18. The drawing device (10) of claim 17, wherein the operating rod (120) is made of steel, and the air gap (S) between the at least one magnet and the head (128) of the operating rod (120) is in the range of 1.5 mm to 5 mm, 2 mm to 4 mm, or 2.5 to 3.5 mm.

Images