METHOD FOR CYCLIC CONTROL OF A STAMP OF A PUNCHING TOOL AND PUNCHING TOOL

Abstract

A method for cyclically controlling a punch (102) of a stamping tool (100), wherein during a cycle of the stamping tool (100) a linear opening movement (122) of the stamping tool (100) is translated into a rotary movement (124) using a gear (118) of the stamping tool (100) and an angular position (128) of a cam (130) of a camshaft (120) of the stamping tool (100) is changed by an angular step (152), wherein during a closing movement (114) of the stamping tool (100) following the opening movement (122) in the cycle, the angular position (128) of the cam (130) set during the opening movement (122) is scanned using a sensing device (126) of the stamping tool (100), wherein a working movement driven by the closing movement (114) (206) of the punch (102) depending on the scanned angular position (128) of the cam (130),wherein, using a pawl freewheel of the transmission (118), the opening movement (122) is decoupled from the closing movement (114), and wherein the angular step (152) of the camshaft (120) performed per opening movement (122) is influenced by an angle between detent positions of the pawl freewheel (138).

Description

Technical FieldThe present invention relates to a method for the cyclical actuation of a punch of a punching tool and to a punching tool having at least one actuatable punch.Prior ArtIn a stamping tool for producing stamped parts with slightly different stamping geometries, certain punches of the stamping tool can be activated or deactivated by actuators in the stamping tool that are controlled from the outside, depending on the embodiment variant just produced. Then, the actuated punches either execute a working movement or do not execute it during a closing movement of the punching tool. Thus, the different punching geometries can be produced in one and the same punching tool. The actuators can be actuated, for example, via electrical, hydraulic or pneumatic signals.DE 14 52 967 C discloses a punching tool for punching strip-shaped material advanced in steps.DE 10 2008 053 591 A1 discloses a cam mechanism for a punching-bending machine.DE 10 2007 015 467 A1 discloses a control method for a punching machine.EP 3 461 569 A1 discloses a motor-driven toggle joint punch for punching openings in sheet-metal workpieces.DE 10 2005 032 994 A1 discloses a forming machine with a transmission for controlling the speed of the forming process.DESCRIPTION OF THE INVENTIONIt is therefore an object of the invention to provide a punching tool with at least one controllable punch and a method for the cyclical control of a punch of a punching tool using means which are as simple as possible in terms of construction.The object is achieved by the subject matters of the independent claims. Advantageous developments of the invention are specified in the dependent claims, the description and the accompanying figures. In particular, the independent claims of one claim category can also be developed analogously to the dependent claims of another claim category.A method for cyclically controlling a punch of a punching tool is presented, wherein during a cycle of the punching tool a linear opening movement of the punching tool is translated into a rotational movement using a gear mechanism of the punching tool and an angular position of a cam of a camshaft of the punching tool is changed by an angular step, wherein during a closing movement of the punching tool following the opening movement in the cycle the angular position of the cam set during the opening movement is scanned using a scanning device of the punching tool, wherein a working movement of the punch driven by the closing movement is carried out as a function of the scanned angular position.Furthermore, a punching tool with at least one controllable punch is presented, wherein the punching tool has a gear for translating a linear opening movement of the punching tool into a rotational movement of a camshaft of the punching tool, and a sensing device for sensing an angular position of a cam of the camshaft during a closing movement of the punching tool, wherein the gear is designed to rotate the camshaft with the cam by an angular step using the opening movement, and the sensing device is designed to control a working movement of the punch driven by the closing movement as a function of the sensed angular position of the cam.A stamped part can be produced from an endless material running off a roller, for example from a metal sheet. The endless material can already have approximately a width of the stamped part at the beginning of a production process for producing the stamped part, in order to achieve a high material utilization. The endless material can be introduced on an input side into a punching tool for producing the stamped part. On an output side of the punching tool, the punching parts and a production residue of the continuous material can be removed from the punching tool.The punching tool has a tool upper part and a tool lower part movable relative thereto. The upper tool part and the lower tool part can be fastened to opposite tool holders of a punching machine. The endless material is guided between the upper tool part and the lower tool part. The upper tool part and / or the lower tool part can be driven. The upper tool part and the lower tool part can be guided with respect to one another by linear guides. The punching tool is cyclically opened and closed by the punching machine. The punching tool can be opened and closed, for example, several hundred times per minute.The punching tool can have successive production positions which pass through the continuous material cyclically starting from the input side. During one cycle, the punching tool is opened, the continuous material is transported to the next production position and the punching tool is closed again. The production positions are each formed both in the upper tool part and in the lower tool part. In each production position, recesses or contours, embossings and / or bends can be introduced into the continuous material when closing the stamping tool using punches mounted in the stamping tool. The punches can be arranged both in the upper tool part and in the lower tool part. A counter piece of a punch can be arranged coaxially to a punch in the other tool part.A punch can be a cutting punch for producing a recess or contour, an embossing punch for producing an embossing and / or a bending punch for producing a bend. The punches may also have combined functions. The punches can be driven into a working movement by a closing movement of the punching tool. In this case, the endless material can first be clamped between the upper tool part and the lower tool part by the closing movement. Subsequently, a spring-mounted punch holder of the punching tool coupled to the punches can be moved further by the punching machine and press the punches on their working movement out of their bearings in the upper tool part and / or lower tool part through, against and / or onto the endless material. The working movement of the punches can be smaller than the closing movement of the punching tool.A gear may be coupled to the tool top and the tool bottom to decrease the linear opening motion. A gear ratio of the transmission may define a ratio between a length of the opening movement and a rotational angle of the rotational movement. Since the opening movement is the same in each cycle, the angle of rotation is always the same. The angle of rotation can be transmitted to the angular step of the camshaft with a further transmission ratio. During the closing movement, the camshaft must be stationary. The camshaft continues to rotate by the same angular step with each identical opening movement at a constant transmission ratio.A cam may be a protrusion on the camshaft. The cam may protrude radially from the camshaft. During the closing movement, it can be sensed whether the cam is arranged at a sensed angular position. A sensing device may be movable relative to the camshaft. The sensing device can be moved by the closing movement for sensing the angular position. When the cam is located at the angular position, contact is made between the cam and the feeler. As a result, the punch receptacle is coupled into the closing movement and the working movement of the punch can be driven by the closing movement.The angular position can be scanned by a sensing cam of the punch receptacle coupled to the punch. The working movement can be carried out when the cam strikes the sensing cam during the closing movement. The sensing device can be designed as the sensing cam. The sensing cam may be a protrusion of the plunger receptacle. The sensing cam can be arranged fixedly on the plunger receptacle. The cam may have a contact surface that abuts a corresponding impact surface of the sensing cam when the cam is disposed at the sensed angular position. When the cam hits the sensing cam, the working movement can be released.The working motion cannot be carried out when the sensing cam dips into a cam gap of the camshaft. A cam gap can be a recess or free space between two flanks of cams of the camshaft. If the camshaft has only one cam, the cam gap between two opposite flanks of the same cam can extend over the rest of a circumference of the camshaft. If the feeler cam does not meet the cam because the cam is located at a different angular position, no contact results between the cam and the feeler cam. The working movement is not released.The working movement can be transmitted from the cam to the sensing device. The punch can be driven by the sensing device. When the cam is aligned with the sensing device, the contact surface of the cam can be aligned transversely to a direction of the closing movement. A baffle surface of the sensing device can likewise be oriented transversely to the direction of the closing movement. A force for driving the punch may be transmitted via the contact surface and the baffle.A stroke of the working movement can be determined by a height of the cam. A stroke of the working movement can begin when the cam is in contact with the sensing device, i.e. when the contact surface impacts the impact surface. A height of the cam can be adapted to the stamp to be operated. The camshaft can have cams of different heights in order to specify different strokes for the same plunger in different cycles.A number of cycles of the punching tool without a working movement carried out between two cycles with a working movement carried out can be influenced by a transmission ratio of the transmission. The number may also be affected by a size of a cam gap between two cam flanks. The transmission ratio can be set as required. Also, the number of cams on the camshaft may be adjusted.For setting the transmission ratio, the transmission can have a rotatably mounted replaceable lever. A free end of the lever may be coupled to an opposite side of the punch. A gear ratio of the transmission may be affected by a length of the lever. The lever can be rotatably mounted in the upper tool part or lower tool part. A counter side can accordingly be formed by the lower tool part or the upper tool part. The lever can be driven by an element rigidly connected to the opposite side. At the free end of the lever, a two-degree-of-freedom bearing may be arranged to transmit the linear opening movement of the element into an arcuate movement of the lever. The bearing can be a rotary thrust joint. For example, an elongated hole or slot in the lever can compensate for a circular error of the lever. The lever can also be driven by a separate coupling device. The coupling device can be formed by a separate lever rotatably mounted on the opposite side, Then a connection between the lever and the coupling device can have a degree of freedom, i.e. be formed as a pure pivot joint.The gear can have at least one replaceable gearwheel pair. The transmission gear ratio may be affected by a gear ratio of the gear pair. One gear of the gear pair may be coupled to the camshaft, the other gear may be disposed between the camshaft and an input of the transmission.The transmission has a freewheel for decoupling the opening movement from the closing movement. A freewheel can only transmit the rotational movement if the rotational movement takes place in a blocking direction of the freewheel. The locking direction coincides with the opening movement. As a result, the rotational movement is transmitted to the camshaft only during the opening movement. The rotational movement takes place only in one direction. The freewheel can be arranged at different positions of the transmission. In particular, the freewheel can be arranged between the lever and a subsequent gearwheel pair of the transmission.The freewheel can be a pawl freewheel. The angular step of the camshaft carried out per opening movement can be influenced by an angle between latching positions of the pawl freewheel. The pawl freewheel can only transmit the rotational movement if at least one pawl of the pawl freewheel engages in a latching position of the pawl freewheel. The pawl freewheel can transmit only a portion of a rotational movement on the drive side to its output side. A remainder of the drive-side rotational movement is slip. As a result, an angular step of the drive side of the pawl freewheel, which angular step is produced by the opening movement, is greater than the angular step transmitted from the output side to the camshaft.The camshaft can have at least one replaceable cam disk. The at least one cam may be disposed on the cam plate. A cam disc can be a ring which has the at least one cam on its outer side. Different cam disks can have different numbers of identical cams. The cams may be arranged distributed at regular intervals over a circumference of the cam disc. An inner side of the cam disc may be adapted to a diameter of a shaft of the camshaft. The cam disc can be connected to the shaft in a rotationally fixed manner and can be released again. The cams can be replaced to set a number of cycles without operating motion.The punching tool can have a brake which is designed to keep the angular position of the camshaft constant during the closing movement. A brake may be a friction brake. To overcome friction of the brake, a minimum torque may be required. The minimum torque can be greater than a drag torque of the freewheel opposite to the locking direction. The brake can also be designed as a further freewheel. A direction of rotation of at least the camshaft is thus unambiguously defined.The punching tool can have at least one further camshaft. The transmission can furthermore be configured to rotate the further camshaft by the angular step using the opening movement synchronously with the camshaft. The further camshaft can be rotated synchronously with the camshaft during the opening movement. The further camshaft can be coupled to the camshaft, for example, via a gearwheel pair having a transmission ratio of one. The further camshaft may have a different direction of rotation than the camshaft. The further camshaft can be scanned by a separate scanning device.Brief description of the FiguresIn the following, an advantageous embodiment of the invention is explained with reference to the accompanying figures. The following are shown: FIG. 1 shows a sectional illustration of an open punching tool according to an exemplary embodiment during a cycle; FIG. 2 shows a sectional illustration of a closed punching tool according to an exemplary embodiment during one cycle; FIG. 3 shows a sectional illustration of an open punching tool according to an exemplary embodiment during a subsequent cycle; and FIG. 4 shows a sectional illustration of a closed punching tool according to an exemplary embodiment during a subsequent cycle.The figures are merely schematic representations and serve only to explain the invention. Identical or identically acting elements are provided with the same reference numerals throughout.Detailed DescriptionFor ease of understanding, the reference numerals to FIGS. 1 to 4 are retained as reference in the following description.FIG. 1 shows a sectional illustration of an open punching tool 100 according to an exemplary embodiment during one cycle. The punching tool 100 is shown here cut by at least one actuatable punch 102 of the punching tool 100. The punching tool 100 has a driven tool upper part 104 and a fixed tool lower part 106. In the lower tool part 106, a die is arranged coaxially to the punch 102 as a counterpart 108 of the punch 102. The upper tool part 104 is mounted on the lower tool part 106 in a linearly movable manner via column guides. The upper tool part 104 and the lower tool part 106 are coupled during operation to a punching machine, not depicted here. The punching machine moves the upper tool part 104 up and down. The upper tool part 104 can be moved up and down several hundred times per minute.The upper tool part 104 is multi-part. A holding-down device 110 of the upper tool part 104 is arranged between the lower tool part 106 and a back plate 112 of the upper tool part 104. The punch 102 is movably mounted in the hold-down 110. The hold-down device 110 precedes the back plate 112 during a closing movement 114 and is placed on a stamped part 116 to be produced. After the holding-down device 110 has been placed on the stamped part 116, the back plate 112 performs a relative movement with respect to the holding-down device 110 on account of the continuous closing movement 114. The relative movement reduces a distance between the hold-down device 110 and the back plate 112. The relative movement can be transmitted at least partially to the punch 102. When the relative movement is transmitted to the punch 102, it extends out of the hold-down 110 and processes the stamped part 116.The stamped part 116 is here made of a single-ply sheet metal. The punch 102 may be a cutting punch and may be configured to punch a cut-out or a contour from the sheet metal. The counterpart can then have a through-opening for a resulting punching scrap. The punch 102 can also be a bending punch and can be designed to bend a partial region of the stamped part 116 out of a plane of the metal sheet. A bending punch can also have a cutting edge and cut a contour of the subregion into the sheet metal before bending. The counter piece 108 can then have a cutout for the bent partial region. The counter piece 108 can also have a spring-mounted counter holder. The counter piece 108 can likewise have a bending edge which specifies a bending radius for the sub-region to be bent. The punch 102 may also be an embossing punch and may be configured to impart an embossing to the die cut 116. The counter piece 108 can have a negative contour of the embossing. A bending punch can also have an embossing contour, in order to emboss, for example, a bead reinforcing the bending.On the back plate 112 of the upper tool part 104, a gear 118 and at least one camshaft 120 are arranged. The gear 118 translates a linear opening movement 122 of the tool upper part 104 along the column guides into a rotational movement 124 of the camshaft 120.A sensing device 126 for sensing an angular position 128 of a cam 130 of the camshaft 120 is movably mounted on the holding-down device 110. The sensing device 126 is coupled to the punch 102. The sensing device 126 is arranged between the hold-down device 110 and the back plate 112. Here, the upper tool part 104 is shown at a top dead center. The sensing device 126 is spaced apart from the camshaft 120.The transmission 118 has a lever 134 coupled to the lower tool part 106 via a driver 132, a gearwheel pair 136 having a defined transmission ratio, and a freewheel 138 arranged between the lever 134 and the gearwheel pair 136. The lever 134, the freewheel 138 and a first gearwheel 140 of the gearwheel pair 136 are arranged on a common rotational axis and are rotatably mounted in the upper tool part 104. The freewheel 138 is designed as a pawl freewheel. The lever 134 is connected in a rotationally fixed manner to a carrier for latching pawls 142 of the freewheel 138. The latching pawls 142 engage in a ratchet wheel 144 of the freewheel 138 at defined positions. The ratchet pawls 142 are configured to carry the ratchet wheel 144 along only in one rotational direction (counter-clockwise in the illustration). The ratchet 144 is rotationally fixedly connected to the first gear 140 of the gear pair 136. A second gearwheel 146 of the gearwheel pair 136 is coupled rotationally fixedly to the camshaft 120 and is mounted rotatably in the upper tool part 104 on a common rotational axis with the camshaft 120. The axis of rotation of the second gear 146 and the camshaft 120 is oriented parallel to the axis of rotation of the lever 134 of the freewheel 138 and the first gear 140.In the opening movement 122 preceding the illustrated top dead center, the lever 134 has been rotated by the driver 132 (counter-clockwise in the illustration) by a first angular step 148 into its illustrated position. The ratchet pawls 142 have carried the ratchet wheel 144 along and rotated by a second angular step 150. The second angular step 150 is smaller than or equal to the first angular step 148 due to the defined engagement positions of the latching pawls 142. The gear pair 136 has translated the second angular step 150 by its gear ratio into an angular step 152 of the camshaft 120. Because the first gear 140 has a greater number of teeth than the second gear 146, the angular step 152 of the camshaft 120 is greater than the second angular step 150. The cam 130 has been rotated into the angular position 128 shown by the preceding angular step 152.In one embodiment, the first gear 140 and / or the second gear 146 are interchangeable with other gears having a greater or lesser number of teeth. The transmission ratio can be set by other gears.In one embodiment, the stamping tool 100 includes a second camshaft 120. The second camshaft 120 is connected to a third gearwheel 154 in a rotationally fixed manner. The third gear 154 meshes with the second gear 146, whereby the second camshaft 120 has a rotational direction opposite to the first camshaft 120. The second gear 146 and the third gear 154 have the same number of teeth. As a result, the second camshaft 120 rotates by the same angular pitch as the first camshaft 120.FIG. 2 shows a sectional illustration of a closed punching tool 100 according to an exemplary embodiment during the cycle from FIG. 1 The punching tool 100 corresponds substantially to the punching tool in FIG. 1 The upper tool part 104 has completely executed the closing movement 114. The upper tool part 104 is shown here at a bottom dead point. In this case, the holding-down device 110 has been placed on the stamped part 116 and the back plate 112 has carried out the relative movement 200 with respect to the holding-down device 110. Since the angular position 128 of the cam 130 has remained constant due to a brake 202 of the transmission 118, the cam 130 is oriented in the angular position 128 shown such that it is in contact with a sensing cam 204 of the sensing device 126. Due to the contact between the cam 130 and the sensing cam 204, a part of the relative movement 200 has been transmitted to the punch 102 and the punch 102 has carried out its working movement 206 and has machined the stamped part 116. The sensing cam 204 is here part of a rear-side punch receptacle of the punching tool 100.The lever 134 has been rotated by the driver 132 (clockwise in the illustration) by an inverted first angular step 148. However, because the one-way clutch 138 slips in this direction, the reverse first angular step 148 is not transmitted to the first gear 140. Here, the brake 202 additionally acts on the first gearwheel 140 and prevents a movement of the first gearwheel 140 on account of a possible drag torque of the freewheel 138.FIG. 3 shows a sectional illustration of an open punching tool 100 according to an exemplary embodiment during a subsequent cycle. The stamping tool 100 corresponds substantially to the stamping tool in FIGS. 1 and 2 The upper tool part 104 has completely executed the opening movement 122. The upper tool part 104 is shown here at the bottom dead point, as in FIG. 1. In this case, the holding-down device 110 has been lifted off the stamped part 116 and the punch 102 has been pulled back into the holding-down device 110.In the opening movement 122 preceding the illustrated top dead center, the lever 134 has been rotated by the driver 132 (counter-clockwise in the illustration) by a renewed first angular step 148 into its illustrated position. The ratchet pawls 142 have carried the ratchet wheel 144 along and rotated by a further second angular step 150. The new second angular step 150 is smaller than or equal to the new first angular step 148 because of the defined engagement positions of the latching pawls 142. The gear pair 136 has translated the new second angular step 150 by its gear ratio into a new angular step 152 of the camshaft 120. Because the first gear 140 has a greater number of teeth than the second gear 146, the re-angular step 152 of the camshaft 120 is greater than the second re-angular step 150. By the preceding renewed angular step 152, the cam 130 has been rotated from the angular position 128 into a second angular position 300. The cam 130 is no longer opposite the sensing cam 204 by the renewed angle step 152.In one embodiment, the first gear 140 and / or the second gear 146 are interchangeable with other gears having a greater or lesser number of teeth. The transmission ratio can be set by other gears. By changing the transmission ratio, the angle step 152 is also changed.In one embodiment, the lever 134 is interchangeable with other levers of different lengths. The first angle step 148 can be adjusted by levers 134 of different lengths.FIG. 4 shows a sectional illustration of a closed punching tool 100 according to an exemplary embodiment during the subsequent cycle from FIG. 3 ; the punching tool 100 corresponds in this case substantially to the punching tool in FIG. 3 ; the upper tool part 104 has completely executed the closing movement 114. The upper tool part 104 is again shown here at the bottom dead point. In this case, the holding-down device 110 has been placed on the stamped part 116 again and the back plate 112 has carried out the relative movement 200 with respect to the holding-down device 110 again. Since the second angular position 300 of the cam 130 has remained constant due to the brake 202 of the transmission 118, the sensing cam 204 dips into a cam gap 400 of the camshaft 120. In this case, the relative movement 200 is not transmitted to the punch 102.In one exemplary embodiment, the camshaft 120 is embodied in two parts. A replaceable cam plate 402 is mounted on a central shaft. The depicted cam plate 402 has four cams 130. In order to set a number of idle strokes without working movement 206, the cam disk 402 can be replaced by another cam disk with more or fewer cams 130. The number of cams 130 affects a length of the cam gap. The larger the cam gap, the more successive cycles the sensing cam 204 dips into the cam gap 402.In other words, the approach presented here enables cycle control in the punching process.A cycle control can be understood to mean a linkage of (cutting) punches in regular cycles, i.e. for example only during every second or third punching stroke. A specific application of the approach presented here is the articulation for the die-cutting packaging of strip contacts. The cycle control presented enables a reduction of tool failures compared to other types of articulation to be achieved. In addition, an increase in the speed (strokes / minute) can be achieved by the mechanical articulation of the separating punches. The mechanical articulation results in a reduction of unused and therefore unavailable replacement parts, such as rotary magnets, plugs and valves, which can fail due to the vibrations during the punching process.The up-and-down movement of the punching machine is transmitted via a lever linkage to a ratchet wheel. This transmits the rotational movement, if appropriate, via a gear mechanism to a camshaft. For increased demands on the accuracy, two coupled camshafts can also be used. Depending on the position of the camshaft(s), the punch is actuated when the tool is closed or the cam drive does not actuate the punch.Up to now, the linkage of the punches is effected via pneumatics or via at least one rotary magnet. The pneumatic system is very slow, since only low lifting speeds are possible. The rotary magnet can fail mechanically due to the permanent vibrations or plug connections can become defective due to moved connections in the upper tool part. This often results in a difficult fault finding, since there is a combination of electronics and mechanics. Failures sometimes only occur in continuous operation, which leads to difficult fault analysis.An application of the linkage presented here for the lamellar contact product family with several million parts per week is immediately possible. The linkage proposed here enables an increase in the stroke speed and a reduction in the tool downtime and simplified fault analysis. The tool runs without special control and can therefore be used on various punching machines. Fewer spare parts are required.During a punching stroke with actuation of the punches, the ratchet wheel is rotated to a defined position at the top dead center of the tool (OT) by the ratchet pawl(s) connected to the articulation lever. Via a gear connection, the camshaft(s) rotates to the first position, where the cam(s) is oriented vertically downward. When closing the tool, the punches cut through the material as they are actuated by the cam(s) of the camshaft(s).When the tool is closed, the starting lever / catch unit is rotated to the next position. A sprung brake on the ratchet wheel prevents it and the camshaft(s) from rotating. When the tool is opened to TDC next, the starting lever / catch unit drives the ratchet wheel to the next position-the camshaft is correspondingly also rotated to the next position by the gear connection. During the following closing process, the camshaft is accordingly positioned with its recess above the cutting punches, whereby the cutting punches are not actuated and do not cut. The sequence repeats itself endlessly, so that a defined number of working strokes and idle strokes always take place. The ratio of working strokes to idle strokes is determined by the angle of rotation of the crank lever, the transmission ratio, the number of detents in the ratchet wheel and the design of the camshaft. In the example shown, one working stroke is carried out followed by two idle strokes as an endless loop.Upon opening, the pawl rotates the ratchet and camshafts to the defined position. Upon closing, the articulation lever brings the ratchet into the next position. The camshafts remain engaged and the cutting punch cuts the material. Upon subsequent opening, the pawl continues to rotate the ratchet and the camshafts one position. During the subsequent closing, the articulation lever brings the latching pawl into the next position. The camshafts are not engaged and the blanking punch does not cut the material.Since the apparatuses and methods described in detail above are exemplary embodiments, they can be modified widely by the skilled worker in the customary manner without departing from the scope of the invention. In particular, the mechanical arrangements and the dimensional relationships of the individual elements to one another are selected merely by way of example.LIST OF REFERENCE CHARACTERS100 Stamping tool 102 Punch 104 Tool upper part 106 Tool lower part 108 Counterpart 110 Holding-down device 112 Back plate 114 Closing movement 116 Stamping part 118 Transmission 120 Camshaft 122 Opening movement 124 Rotational movement of the camshaft 126 Sensing device 128 Angular position 130 Cam 132 Driver 134 Lever 136 Gearwheel pair 138 Freewheel 140 First gearwheel 142 Ratchets 144 Ratchet wheel 146 Second gearwheel 148 First angular step 150 Second angular step 152 Angular step 154 Third gearwheel 200 Relative movement 202 Brake 204 Sensing cam 206 Working movement 300 Second angular position 400 Cam gap 402 Cam disk

Claims

Method for cyclically controlling a punch (102) of a punching tool (100), wherein during a cycle of the punching tool (100) a linear opening movement (122) of the punching tool (100) is translated into a rotational movement (124) using a gear mechanism (118) of the punching tool (100) and an angular position (128) of a cam (130) of a camshaft (120) of the punching tool (100) is changed by an angular step (152), wherein in a closing movement (114) of the punching tool (100) following the opening movement (122) in the cycle the angular position (128) of the cam (130) set during the opening movement (122) is scanned using a sensing device (126) of the punching tool (100), wherein a working movement (206) of the punch (102) driven by the closing movement (114) is carried out as a function of the scanned angular position (128) of the cam (130), wherein the opening movement (122) is decoupled from the closing movement (114) using a pawl freewheel of the transmission (118), and wherein the angular step (152) of the camshaft (120) carried out per opening movement (122) is influenced by an angle between latching positions of the pawl freewheel (138).Method according to Claim 1, in which the angular position (128) is scanned by a sensing cam (204) of a die receptacle coupled to the die (102), the working movement (206) being carried out when the cam (130) strikes the sensing cam (204) during the closing movement (114).Method according to Claim 2, in which the working movement (206) is not carried out when the sensing cam (204) dips into a cam gap (400) of the camshaft (120).Method according to one of the preceding claims, in which the working movement (206) is transmitted from the cam (130) to the sensing device (126) and the plunger (102) is driven by the sensing device (126)Method according to claim 4, wherein a stroke of the working movement (206) is determined by a height of the cam (130).Method according to one of the preceding claims, in which a number of cycles of the punching tool (100) without the working movement (206) being carried out between two cycles with the working movement (206) being carried out is influenced by a transmission ratio of the transmission (118).Method according to one of the preceding claims, in which a number of cycles of the punching tool (100) without a working movement (206) carried out between two cycles with a working movement (206) carried out is influenced by a size of a cam gap (400) between two cam flanks.Punching tool (100) having at least one controllable punch (102), wherein the punching tool (100) has a gear mechanism (118) for translating a linear opening movement (122) of the punching tool (100) into a rotational movement (124) of a camshaft (120) of the punching tool (100), and a sensing device (126) for sensing an angular position (128) of a cam (130) of the camshaft (120) during a closing movement (114) of the punching tool (100), wherein the gear mechanism (118) is designed to rotate the camshaft (120) with the cam (130) by an angular step (152) using the opening movement (122), and the sensing device (126) is designed to control a working movement (206) of the punch (102), which working movement is driven by the closing movement (114), as a function of the sensed angular position (128) of the cam (130), wherein the transmission (118) has a freewheel (138) for decoupling the opening movement (122) from the closing movement (114), wherein the freewheel (138) is a pawl freewheel, and wherein an angular step (152) of the camshaft (120) carried out per opening movement (122) is influenced by an angle between latching positions of the pawl freewheel.Punching tool (100) according to one of the preceding claims, having a brake (202) which is designed to keep the angular position (128) of the camshaft (120) constant during the closing movement (114).The stamping tool (100) according to any one of the preceding claims, wherein the gear mechanism (118) comprises a rotatably supported replaceable lever (134), a free end of the lever (134) being coupled to an opposite side of the stamping tool (100), wherein a transmission ratio of the gear mechanism (118) is influenced by a length of the lever (134).Punching tool (100) according to one of the preceding claims, in which the gear mechanism (118) has at least one replaceable gearwheel pair, wherein a transmission ratio of the gear mechanism (118) is influenced by a transmission ratio of the gearwheel pair.Punching tool (100) according to one of the preceding claims, in which the camshaft (120) has at least one replaceable cam disc (402), wherein the at least one cam (130) is arranged on the cam disc (402).Punching tool (100) according to one of the preceding claims, having at least one further camshaft (120), wherein the gear mechanism (118) is further designed to rotate the further camshaft (120) by the angle step (152) synchronously with the camshaft (120) using the opening movement (122).

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