Set of interchangeable crimp units

The present invention relates to a set of interchangeable crimp units for a crimping machine. According to the invention each crimp unit comprises an integrated sensor for measuring a crimping force or a crimping displacement during the crimping process.

CROSS REFERENCE TO RELATED APPLICATIONS

FIELD OF THE INVENTION

The present invention generally relates to a set of interchangeable crimp units for crimping machines. The crimp units are each used for crimping a work piece, in particular for crimping a plug with at least one cable. Furthermore, the present invention relates to a crimping machine with a set of interchangeable crimp units.

BACKGROUND OF THE INVENTION

DE 199 03 194 A1 discloses that during the crimping process of a work piece the crimping force depends on a plurality of factors, e.g. of the material, the cross section or geometry of a cable, the number of single wires in a cable, the distribution of single wires along the cross section and the surface of the single wires. Furthermore, the crimping force might depend on the electrical contact element or plug being crimped with the cable. The crimping force might furthermore depend on tolerances of the material thickness of the contact element, the hardness of the contact element, the composition of the contact element, the build-up of a groove indentation, the build-up of a face or transitional regions of the plug, the surface properties of the crimped surfaces, the presence of a lubricant at the crimped surfaces, the length of the crimping region and/or the length of rolled plastically deformed regions of the plug. The crimping force is also influenced by the shape of the die, the die profile, the die surface, the velocity of deformation and the like. Finally, the crimping force might also depend on operating or environmental conditions, on the used actuators, on the mechanical chain or drive mechanism for actuating the dies, on wear, on play of guidances, on external shocks, on contaminations, on missarrangements or on faulty components, temperatures and the like.

On the basis of measuring the crimping force it is possible to evaluate the crimping process. For a simple non-limiting example for the crimping process of a plug with a cable having 19 strands the predetermined maximum of the crimping force (or a tolerance region of this maximum) might be well known. If some of the strands are missing in the crimped cross section of the cable this leads to a deviation of the crimping force from the predetermined tolerance region of the maximum of the crimping force. For an evaluation of the crimping process it is possible to evaluate discrete values of the crimping force, in particular by evaluating minima and/or maxima of the crimping force curve or by sensing time intervals or crimping displacement curves between the minimum and the maximum), or by evaluating changes of the crimping force, of the velocity of a change of the crimping force and the like. The result of any such evaluation might be used for automatically sorting out crimped work pieces being produced by a faulty crimping process. Furthermore, it is possible to document the crimping force and/or the crimping displacement for some or each crimping process. Such documentation might be used e.g. in the case of an airplane crash for proving that the crimp of a plug with a cable in the airplane was produced according to the rules.

For sensing a crimping force during a crimping process DE 195 48 533 C2 discloses monitoring the current of an electric actuator used for producing the crimping force. In case that the current is larger (or smaller) than a predetermined current this might be taken as an indicator that the crimping process has not been performed according to the rules. Furthermore, DE 195 48 533 C2 discloses sensing the crimping displacement by a sensor during the crimping process. The measured crimping displacement is transferred to a control unit. The control unit evaluates the crimping process on the basis of the measured crimping displacement.

It is also known to integrate a force sensor into the force flow between a crimping unit and an anvil or a punch of a crimping machine, see DE 196 22 390 A1 and EP 2 181 602 A1.

According to EP 0 902 509 A1 a motor drives an eccenter drive via a transmission. The eccenter drive produces a vertical movement of a tool holder with a force sensor. In a calibration process for the force sensor the tool holder is coupled with a crimp simulator with an integrated second force sensor used during the calibration process. It is suggested to use a comparatively expensive sensor, in particular a quartz crystal force sensor for the second force sensor. EP 0 902 509 A1 also discloses an evaluation of the crimping force curve for evaluating the crimping process and for generating failure indications.

According to DE 43 37 797 B4 a force sensor is integrated into an anvil or punch, wherein the force sensor is interposed between a tool holder and a drive element. The force sensor comprises an upper surface and a lower surface. The upper surface is actuated by the drive element whereas the lower surface transfers the crimping force to the tool holder. The force sensor is located in a recess defined by both the tool holder and the drive element. The sensor comprises two piezo discs and an interposed disc electrode. The measurement signal of the sensor is transferred to a control unit.

EP 1 381 123 A1 discloses a tool receiver provided at the crimping machine. The tool receiver is moved by a drive in vertical direction. An upper tool is received and locked in the tool receiver. The tool receiver comprises a crimping force sensor unit having a housing. In the force flow between a bottom and a cover of the housing four force sensors are interposed in mechanically parallel arrangement. The four force sensors are located in a common plane having an orientation transverse to the crimping axis.

According to DE 40 38 658 A1 and EP 0 989 636 B1 a lower die half of a crimping machine is supported by a plate like support, a base plate, a mounting plate and a mount. A crimping force cell built by a piezo element is integrated into the mounting plate.

According to DE 41 11 404 A1 a plate like anvil is supported by a plurality of pressure sensors located in mechanically parallel arrangement in a common horizontal plane. The pressure sensors are built by piezo elements embedded into a damping cushion built by silicone.

DE 100 41 237 B4 discloses a crimping machine which is built with an anvil, a base plate, a receiving plate, a force sensor, a guiding element and a pressure bolt being guided in the guiding element. Guiding element, force sensor, receiving plate and base plate are screwed to one single unit.

EP 0 878 878 A2 discloses an adapter for measuring a crimping force. The adapter is integrated into the force flow of the crimping force with two force sensors located in mechanically parallel arrangement.

WO 2007/067507 A1 discloses a crimping machine wherein the dies build a component of the crimp unit. The crimp unit is exchangeable for being able to crimp work pieces of different sizes or types or in order to replace a damaged crimp unit. The crimp units are equipped with a storage unit and/or a control unit. The control unit and the storage unit are used for storing characteristic data of the crimp unit, the dies, the crimping displacements and for the types of work pieces crimped by this crimp unit. For the use of one crimp unit the stored data is read out and processed by a control unit of the crimping machine. WO 2007/067507 A1 also mentions a control of the crimping process without further specification if this control strategy bases upon measurements of the crimping displacement or bases upon the crimping force. In any case the measurement of the crimping displacement or the crimping force seems to be done externally from the crimp unit. Furthermore, the crimping machine comprises a feeding device for automatically feeding plugs to the crimp unit in a controlled fashion. The feeding device successively and automatically supplies a plurality of work pieces to the crimp unit. The movement of the work pieces along the feeding device is measured by a position sensor. It is possible that the feeding device is located spaced from or adjacent the crimp unit or coupled with the crimp unit.

Also U.S. Pat. No. 6,047,579 suggests storing characteristic data in a storage unit associated with a die. The stored data is wirelessly transmitted from the die to the crimping machine.

DE 298 08 574 U1 discloses a load cell designated for a crimping machine. The load cell is located laterally from the crimping dies. The load cell is built with force sensors being located between two plates.

DE 82 24 332 U1 discloses a protective housing of a crimping machine. In order to increase the operational safety after inserting the work piece into the dies the working stroke of the crimping machine is only admitted if the protective housing is closed. The protective housing is built by a transparent plastic material. The protective housing has an opening at its front wall for inserting the work piece. Also EP 0 735 308 A1 discloses a protective cover made of a transparent plastic material.

EP 1 635 432 A1 discloses die holders being guided against each other by guiding rods. The dies held by the die holders have a plurality of nests of differing geometries located one besides another. The crimping process according to EP 1 635 432 A1 is controlled on the basis of signals of crimping force sensors.

OBJECT OF THE INVENTION

It is an object of the invention to disclose a crimping machine or components of a crimping machine providing the option of measuring a crimping force and/or a crimping displacement.

Furthermore, it is an object of the invention to provide a crimping machine or components of a crimping machine with a plurality of uses and/or for different types of work pieces and the like.

Another object of the present invention is to increase the precision of sensing of a crimping force or crimping displacement.

The present invention also eases the assembly and disassembly process for adapting the crimping machine for different purposes.

SUMMARY OF THE INVENTION

The above cited prior art is based on the established concept that a sensor should be a fixed component of the crimping machine wherein the sensor is not exchangeably integrated into the actuation mechanism of the crimping machine. Also the electrical connection of the sensor for transferring the measurement signals and for the supply of electrical energy is a fixed part of the crimping machine. Any adaptation of the crimping machine to differing crimping processes (e.g. for different tools, for different types of work pieces or geometries of work pieces) for these embodiments requires a change of the construction of the crimping machine itself.

Differing from this established prejudice the invention for the first time suggests the use of a set of interchangeable crimp units for a crimping machine wherein each crimp unit comprises a pair of die holders. Dies held by these die holders might differ with respect to the number of nests, the nest contours, the extension along the crimping axis and the like. By use of the set of crimp units it is possible to use one and the same crimping machine in a multifunctional way by simple exchange of one crimp unit of the set with a different crimp unit of the set.

The die holders each comprise a coupling region for interchangeable coupling the crimp unit with the crimping machine. It is possible that the set of crimp units comprises crimp units with differing coupling regions for coupling the crimp units with different crimping machines. Furthermore, it is possible to use different crimp units with one and the same crimping machine wherein the different crimp units differ with respect to their sizes, the integrated sensor, the holding device and/or the crimping contour. It is also possible that a plurality of crimp units are identical for providing the option to replace a damaged crimp unit by a new crimp unit.

The invention includes integrating a sensor into each of the crimp units of the set. The sensor measures a force correlating with the crimping force and/or a crimping displacement. Accordingly, the inventive approach leaves the established route of the skilled person that the sensor has to be a fixed component of the crimping machine. Instead the invention accepts that the plurality of crimp units designated for one and the same crimping machine or differing crimping machines are each equipped with their own sensor. For the crimping machine according to the prior art a damaged sensor requires a reconstruction and repair of the crimping machine itself leading to outage time. For the inventive embodiment a damage of a sensor might be encountered by a replacement of the crimp unit with the damaged sensor by a new crimp unit.

It is also possible that differing crimp units are equipped with sensors having different measurement sensitivities. In case that according to the prior art a fixed sensor is integrated into the crimping machine, this fixed sensor has to be able to measure and support the maximum of the crimp force for any possible crimping process. Taking the limited resolution of a sensor and of the processing of the sensor signal, the measurement precision reduces when using the crimping machine for a crimping process with a smaller maximum of the crimping force. For the inventive crimp units, the crimp units might have sensors of different measurement regions or sensitivities. Accordingly, for differing crimping processes, individual crimp units might be chosen wherein the measurement region fits the maximum of the expected crimping force leading to a large precision and high resolution of the measured crimping force.

Furthermore, according to the invention, it is possible to locate the sensor in the crimp unit close to the dies. Longer transfer paths between the dies and the sensor according to the prior art deteriorate the measurement precision and increase the influence of errors. For the integration of the sensor into the crimp unit there are a lot of different options. According to a non-limiting example the sensor might be integrated into one of the die holders. Furthermore, it is possible that the sensor is located parallel to the force flow of the die holders during the crimping process. It is possible that the sensor is held or contacted by both of the two die holders. Furthermore, it is possible that the sensor is held between two parts of one die holder. Furthermore, it is possible that a die holder comprises a recess wherein the sensor is located. Any deformation of the die holder results in a bias of the sensor with a force which correlates with the crimping force. For another embodiment of the invention, the sensor is located in a coupling region of the crimp unit with the crimping machine. In case that the supporting surfaces of the sensor are integrated into the crimp unit and not freely accessible, it is possible that the crimp unit builds a protection of the sensor in disassembled state of the crimp unit.

For another embodiment of the invention, the crimp unit is equipped with a protective cover. The protective cover provides at least partially a cover of the parts of the crimp unit being moved during the crimping process. Furthermore, the protective cover might serve for protecting the components of the crimp unit against damages or contaminations, in particular when the crimp unit is not assembled with the crimping machine or during the storage of the crimp unit or during the transportation process.

The protective cover might have any shape and size and might be produced from any material or materials. For a preferred embodiment of the invention, the protective cover is at least partially built by a transparent or translucent material, e.g. acrylic glass. This embodiment has the advantage that it is possible to optically monitor the insertion process of the work piece into the dies and/or to monitor the process of replacing a crimp unit or of replacing the dies. Furthermore, it is possible that by means of the transparency of the protective cover the operator is able to optically inspect or monitor the crimping process itself.

For another embodiment of the invention, the die holders of the crimp units are held at each other in a loss-proof fashion. This might be done by a holding device that generally does not block a relative degree of freedom of the die holders in the crimping direction. However, it is also possible that the relative degree of freedom between the die holders is blocked in an unassembled state of a crimping unit, whereas with the assembly of the crimp unit with the crimping machine, the blocking of the relative degree of freedom is automatically released.

Any suitable means might be used for guiding the two die holders. For a preferred embodiment of the invention, the die holders are directly guided against each other. For a very simple guidance at least one guiding bolt or pin is used which is held by one of the die holders or which are held by one or each of the die holders. The guiding bolt or pin is guided in a guiding recess of the other die holder.

It is also possible to use two guiding bolts for additionally blocking a relative rotational degree of freedom of the die holders around the crimping axis. For a preferred embodiment, the two guiding bolts are located laterally on different sides from the crimping axis providing a compact design and a stiff guidance. It is possible that the guidance by at least one guiding bolt is permanently present for any distance of the die holders. However, it is also possible that at least one guiding bolt only enters into the respective guiding recess at the end of the crimping stroke. In the case of using two guiding bolts, these guiding bolts might have different lengths. During the crimping process, the longer guiding pin of that two guiding pins enters into a respective guiding recess before the shorter guiding pin of said two guiding pins enters into its respective guiding recess.

The sensor might be located at any location of the crimp unit, in particular in one of the die holders. For a preferred embodiment of the invention the sensor is located centrally when seen along the crimping axis. This embodiment might lead to a symmetrical bias of the sensor. Furthermore, the central arrangement of the sensor might provide a high sensitivity of the sensor. Furthermore, the central arrangement of the sensor at least reduces any asymmetric normal forces or bending moments acting upon the sensor.

The die holders might be designed and configured for holding dies having only one nest or for holding dies having a plurality of nests located one besides another. In this case one and the same crimp unit and one and the same die might be used for crimping different work pieces with differing crimping contours and/or cross sections.

For a preferred embodiment, the crimp units comprise a releasable interface or a releasable plug. The interface or plug serves for supplying electrical energy to the sensor and/or for transmitting an output signal of the sensor to a processing unit of the crimping machine. When assembling a crimp unit with a crimping machine the plug or interface is used for the electrical coupling between crimp unit and crimping machine. A replacement of a crimp unit by another crimp unit only requires an exchange of the interface or plug.

It is possible that the crimping unit transfers an output signal of the sensor via the interface or the plug to a control unit located separately from the crimp unit, in particular a control unit building a fixed component of the crimping machine. For one embodiment of the invention also a control unit might be integrated into the crimp unit. In this case, the control unit is equipped with control logic for processing an output signal of the sensor. The processed output signal might then be transferred via the interface or the plug to an external control unit of the crimping machine.

There are a lot of options for processing the output signal of the sensor in a control unit integrated into the crimp unit. For a non-limiting example, it is possible to calibrate the crimp units at the manufacturer or at another place. The resulting calibration factors or calibration curves might be modeled or stored in the control unit (or in a storage unit which is also integrated into the crimp unit). During the use of the crimp unit in the crimping machine, the control unit integrated into the crimp units determines a modified output signal under consideration of the calibration factor or curve. Accordingly, the crimp unit supplies adapted or modified output signals wherein the modified signal might already consider manufacturing tolerances or the calibration factors.

The crimp units of one set might differ with respect to their coupling regions, their sensors, their die holders and/or plugs or interfaces. The set of crimp units might be offered by the manufacturer so that a customer is able to choose an appropriate crimp unit from the set of crimp units. However, it is also possible that a customer acquires the set of crimp units wherein the crimp units are designated for different uses, in particular for an operation of the crimping tool with different dies, sensors, work pieces and/or crimping machines.

For another embodiment of the invention, the crimp units of the set of crimp units are provided with unique interfaces or plugs. The unique interfaces or plugs provide the option of coupling differing crimp units without additional measures with the respective interfaces or plugs of the crimping machine.

For another embodiment of the invention, the different crimp units of one set comprise sensors having different measurement regions or sensitivities. For this embodiment, the customer is able to choose between different crimp units depending on the expected maximum of the crimp force during the crimping process.

Another inventive solution is given by a crimping machine equipped with a set of crimp units as specified above.

It is possible that a crimping machine according to the invention is provided with a control unit. The control unit is equipped with control logic. The control logic determines a crimping force and/or a crimping displacement under consideration of at least one calibration factor and/or at least one calibration curve. It is possible that the calibration factor and calibration curve is determined by a calibration process at the manufacturer. The calibration factor or calibration curve is stored by the manufacturer on the control unit or an associated storage unit. However, it is also possible that the calibration factor or calibration curve is determined by a calibration procedure performed by the customer, see also the crimp simulator used for a calibration process as described in EP 0 902 509 A1.

For another embodiment, the control unit chooses between a plurality of calibration factors or calibration curves for different crimp units, different dies and/or different work pieces for calculating the crimping force and/or the crimping displacement from the output signal of the sensor. It is also possible that the operator manually inputs the respective calibration factor or calibration curve. For another embodiment the operator inputs the used type of crimp unit or used type of die wherein in this case the calibration factor or calibration curve is automatically determined by the control unit from a file with a plurality of stored calibration factors or calibration curves or from a field of characteristic data. It is also possible that the used type of crimp unit is automatically sensed by scanning a label, wherein in this case the calibration factor and the calibration curve is automatically chosen from a plurality of calibration factors or calibration curves in dependence on the scanned label.

If a die forms a plurality of nests, the sensitivity of the sensor of the crimping force (so also the calibration factor or calibration curve) might be dependent on the nest which is used for the crimping process. For one embodiment of the invention, the control logic uses different calibration factors or calibration curves for different nests of the die for calculating the crimping force or crimping displacement from the output signal of the sensor. The used nest of the plurality of nests might be manually input or automatically detected.

For optimizing the control of the crimping process and the operation of the crimping machine the crimping machine might have an additional sensor for sensing the crimping displacement. For one embodiment, it is possible that a control unit determines a curve representing the crimping force depending on the crimping displacement. The additional sensor for sensing the crimping displacement might be located at any position of the crimping unit, the crimping machine or the actuating mechanism of the crimping machine.

DETAILED DESCRIPTION

FIG. 1is a rough schematic view of a crimp unit1. The crimp unit1is built with die holders2,3wherein one die holder2builds a kind of moved punch and the other die holder3builds a kind of fixed anvil. At the opposing faces the die holders2,3each build receivers4a,4bdesignated for holding dies or die halves5,6at the die holders2,3. Furthermore, the die holders2,3comprise coupling regions located at the back faces or at the surfaces facing away from each other. The coupling regions7a,7bserve for coupling the die holders2,3with a crimping machine8. In the shown embodiment, only an upper part9and a lower part10(shown in dashed line) of the crimping machine8are shown. During the crimping process the upper part9is moved by any actuator (in particular a hydraulic or electric actuator) along a crimping path12along a crimping axis11towards the lower part10. The actuator produces a crimping force13. Along the crimping path12and by means of the crimping force13a work piece (in particular a plug with a cable located therein) is plastically deformed between the front surfaces of the die halves5,6.

A sensor14is integrated into the crimp unit1.FIGS. 1 to 6show different types of integrations of the sensor14into the crimp unit1in schematic views:

According toFIG. 1the die holder3is built with die holder parts15,16. The sensor14is housed or supported between the die holder parts15,16. The sensor14comprises parallel biasing surfaces17a,17b. The biasing surfaces17a,17bare pressed against front faces of the die holder parts15,16with the crimping force13. The sensor14produces an output signal correlating with the crimping force13. The output signal is transferred by a plug or an interface18to a control unit of the crimping machine8. For the shown embodiment the sensor14is located in line in the force flow from the lower part10over the die holder part16, the sensor14, the die holder part15, the die receiver4band the die half6to the work piece.

For the embodiment shown inFIG. 2the sensor14is located in the region of the die receiver4b. In this case a biasing surface17bof the sensor14is supported at the die holder3, whereas another biasing surface17a(which is located in the region of the die receiver4) is supported at the die half6. Here, the sensor14is located in line between the die holder3and the die half6. However, for a differing embodiment it is also possible that the die half6is (additionally to the support at the biasing surface17a) also supported at an additional surface built by the die holder3. This additional surface is located in the region of the die receiver4b. The additional support provides a parallel force flow between the die half6and the die holder3for partially unloading the sensor14.

Differing from the embodiment shown inFIG. 1for the embodiment shown inFIG. 2the output signal of the sensor14is transferred to the crimping machine8by a plug or interface18located in the coupling region7b. With the connecting process between the lower part10and the die holder3the plug or interface18establishes an electric connection with a plug or interface75located at the lower part10for transferring the output signal of the sensor14(inFIGS. 3 to 6for a simplification of the representation the cable associated with the sensor14as well as the plug or interface18are not shown).

According toFIG. 3the sensor14is located in the coupling region7b. In this case a biasing surface17aof the sensor14is supported at the die holder3. The other biasing surface17bis supported in the coupling region7bat the lower part10. Here, the force flow passes in line from the lower part10over the sensor14to the die holder3. However, as shown schematically inFIG. 3there might also be a parallel force flow via a path over the sensor14to additional contact surfaces between the die holder3and the lower part10.

For the embodiment shown inFIG. 4the die holder3comprises a recess19. The sensor14is located in the recess19. For this embodiment, the bias of the sensor14requires an elastic deformation of the die holder3due to the crimping force13in deformation regions20a,20b. The deformation regions20a,20bare preferably located laterally from the sensor14. A component of the crimping force13biases the deformation regions20a,20b, whereas the other component of the crimping force13biases the sensor14.

According toFIG. 5the sensor is located parallel to the force flow between the die halves5,6. For this embodiment, the sensor14is both supported by the die holder2as well as by the die holder3with its biasing surfaces17a,17b. The biasing surfaces17a,17bmight be biased in the region of the die receivers4a,4bor remote from the die receivers4a,4b. For this embodiment, the sensor14comprises a deformation region21for providing the crimping displacement12. For the shown embodiment, the sensor14is biased over the whole crimping displacement12. However, for a modified embodiment it is possible that the sensor is located with a kind of play between the die holders2,3such that the sensor14is only biased at the end of the crimping path12. In this case the sensor14is only in one direction fixed at one of the die holders2,3having a spacing to the other die holder. For this embodiment, the sensor14establishes a contact with the other die holder3,2after closing the spacing. However, it is also possible that a part of the sensor14is fixed at the die holder2whereas the other part of the sensor14is fixed at the die holder3. The two parts of the sensors14interact with each other after overcoming the spacing.

FIG. 6schematically shows a sensor14being fixed both at the die holder2and at the die holder3. The sensor14might be a force sensor of any type. However, it is also possible that according toFIG. 6the sensor senses the relative movement of two sensor parts each being held by one of the die holders2,3so that the sensor14measures the relative crimping displacement. For another embodiment, the crimp unit1comprises both a displacement sensor and a force sensor.

FIG. 7more detailed shows a possible embodiment of a crimping machine8. A crimp unit1is interposed between the lower part10and the (here covered) upper part9. In the coordinate system in the following figuresaxis z denotes a crimping axis being slightly inclined relative to the vertical direction to the rear side,axis y denotes a longitudinal extension of the die halves5,6and a direction for inserting die holders2,3into the coupling regions7a,7b(see also the following description)axis x denotes a transverse axis of the die halves5,6which in particular corresponds to the longitudinal axis of the plug and the cable when inserted into the crimp unit1.

FIG. 7shows the coupling region7bat a front face. The coupling region7ais covered by a cover plate22which in a closed state is held at the crimping machine8by a securing screw. In the shown state, the cover plate22blocks a movement of die holder3out of the coupling region7a—a removal of die holder3from the crimping machine8is only possible when disassembling the cover plate22.

FIG. 8shows the mounting of the crimp unit1by the die holders2,3at the upper and lower parts9,10of the crimping machine. According toFIG. 8the coupling regions7a,7bof the die holders2,3comprise T-shaped extension23cooperating with corresponding coupling regions24a,24bof the upper part9and the lower part10. For the shown embodiment, the coupling regions24a,24bare built by T-shaped grooves25,26. The longitudinal axes of the T-shaped grooves25,26have an orientation parallel to the y-axis. For the shown embodiment the T-shaped grooves are built by holding elements27being fixed at the base body of the upper and lower part9,10. InFIG. 8also a locator28is shown. The locator28serves for introducing a work piece (in particular a plug with a cable) in a predetermined relative position and orientation between the die halves5,6and/or for holding the work piece in this position and orientation before and/or during the crimping process. The locator28comprises a pivoting bolt29defining a pivoting axis30. Furthermore, the locator28comprises a latching unit located in an upper end region of the pivoting bolt29. Furthermore, the locator28comprises a holding unit23which is pivotable around a pivoting axis32. The pivoting axis has an orientation parallel to the y-axis. A pivoting movement of the holding unit33biases a spring. For the shown embodiment the holding unit33is built by an angled holding metal sheet which serves for fixing the work piece at the locator28.

FIGS. 8 and 9show handling means34being fixed at the die holder3. The handling means extend parallel to the x-axis. For the shown embodiment, the handling means34are built by rotatable bolts or sleeves. The handling means34serve for holding the crimp unit1or die holder3with the fingers of the operator. Furthermore, the handling means34might be used for guiding the crimp unit1during the coupling process via the coupling regions7. According toFIG. 9the die halves5,6are held at the die receivers4a,4bof the die holders2,3. The die halves5,6have a longitudinal extension parallel to the y-axis. Furthermore,FIG. 9shows two guiding bolts35,36located in both sides of the die halves5,6and being held by die holder3. The guiding bolts35,36enter into guiding recesses37,38of die holder2for providing a guidance for the die holders2,3during the crimping process.

As shown in the sectional view ofFIG. 10the guiding bolt35being located closer to the operator of the crimping machine8is shorter than the other guiding bolt36. The guiding bolts35,36are received with a close fit in corresponding bores of the die holder3wherein the bores have an orientation parallel to the z-axis. The die holder2comprises the guiding recesses37,38wherein the guiding recesses37,38are aligned with the guiding bolts35,36. The guiding recesses37,38are here built by bores wherein the diameter of the bores builds a loose fit with the diameter of the guiding bolts35,36. Due to the different lengths of the guiding bolts35,36the front guiding bolt35only enters into the related guiding recess at the end of the crimping process, in particular after finishing any empty stroke. If the die holders2,3are wide opened, the guiding bolt35is located distant from the die holder2. This distant location of the guiding bolt35from the die holder2provides a kind of window for the operator at the front side for inspecting the interior of the crimp unit1and for inspecting the die halves5,6as well as for monitoring the insertion and positioning process of the plug and the cable into the die halves5,6.

FIGS. 9 and 10show one example for the design of the coupling of the die halves5,6with the die holders2,3at the die receivers4a,4b. The die halves5,6have a generally plate like design. The die halves5,6are insertable into a corresponding slot, a recess or groove39,40of the die holders2,3. Supporting and centering bolts41extend transverse to the plate like base body of the die halves5,6. The supporting and centering bolts41have an orientation parallel to the x-axis. In the sectional view ofFIG. 10the centering bolts41are located at the corners of a rectangle. Two of the supporting and centering bolts41are each located at the die holders2,3. The supporting and centering bolts41are positioned in half-shell shaped receivers42on both sides of the slots, grooves or recesses39,40of the die receivers4a,4b. This design guarantees an exact positioning of the die halves5,6. On the other hand the supporting and centering bolts41serve for supporting the crimping forces13between the die halves5,6and the die holders2,3. Additionally, the die halves5,6are each fixed at the die holders2,3by a screw43. The screws43extend parallel to the x-axis. Furthermore,FIG. 10shows a securing bolt44which is movable along the z-axis in a bore of the lower part10. The securing bolt44is biased by a spring (not shown) into the state shown inFIG. 10. In this state the securing bolt44extends through a recess45of die holder3for building a positive lock that avoids that the die holder3exits inFIG. 10to the left from the T-groove26. Due to the coupling of the die holders2,3by guiding bolts35,36the securing bolt44indirectly also serves for securing the die holder2. The die holder2is additionally secured by the cover plate22as described above. For removing the crimp unit1from the crimping machine8it is necessary to actuate the securing bolt44manually in downward direction which might be done by actuating the actuating means46as shown inFIG. 7.

For the shown embodiment ofFIGS. 7 to 10the coupling regions7a,7bare built by T-shaped extensions23and the recess45and contact surfaces of the die holder2with the cover plate22. This design provides an exchangeable coupling of the crimp unit1with the crimping machine8as well as a fixation in the assembled state. The die receivers4a,4bof the crimp unit1are in the shown embodiment built by slots, recesses or grooves39,40, the receivers42and the bore or thread for the screw43for a releasable fixation of the die halves5,6at the die holders2,3.

FIGS. 11 to 14show a set of crimp units1a,1b,1c,1das being offered and sold by the manufacturer or a company for the use of different die halves5,6and/or for the coupling with different crimping machines8. The crimp units1ofFIGS. 11 to 14have identical coupling regions7a,7bso that these crimp units1are designated for use in a particular crimping machine8or different crimping machines comprising corresponding coupling regions.

As shown inFIG. 11the coupling regions7a,7bcomprise (additionally to the extensions23) guiding grooves47being engaged by corresponding protrusions of the upper and lower parts9,10.FIG. 11shows the crimp unit1according to the embodiment shown inFIGS. 8 to 10wherein the die receivers4a,4bare built with the receiver42and a bore48for the screw43.

FIG. 12shows a crimp unit1bwith a differing design of the die receiver4a,4b: Here, the die receivers4a,4bhave a protrusion or rip49extending along the y-axis. The protrusion or rip49has a generally rectangular cross section in the y-z-plane. The rectangular cross section does not change along the y-axis. The die receivers4a,4bare designated for die halves5,6having slots, grooves or recesses at the side facing towards the die receivers4a,4b. The slots, grooves or recesses have a cross section corresponding to the cross section of the protrusion or rip49. For the assembled state of the die halves5,6in the die receivers4a,4bthe die halves5,6embrace the protrusions or rips49a,49bin a U-like fashion. Additionally the protrusions or rips49comprise a transverse thread extending parallel to the x-axis. A mounting screw43is screwed into this transverse thread. Accordingly, the die receivers4a,4bare in this case built by the combination of the protrusions or rips49with the screws43or a bore or a thread for the screws43. Additionally, the die halves5,6might contact with their front surface at contact or guiding surfaces50of the die holders2,3for guiding purposes.

For the embodiment shown inFIG. 13the die receivers4a,4bare built with slots, recesses or grooves51extending parallel to the y-axis. Protrusions or rips formed by the die halves5,6enter into these slots, recesses or grooves51. The die halves5,6are supported at a step or contact surface at the upper surface of the die receivers4a,4b. It is also possible that the die halves5,6have a plate-like design with a geometry appropriate for introducing the die halves5,6into the slots51. For a fixation of the die halves5,6in the die receivers4a,4bthe die receivers4a,4bcomprise through bores52extending parallel to the y-axis. It is possible to insert a pin or screw into these through bores52. The pin or screw also extends through a corresponding through bore of the die halves5,6. Accordingly, in the crimp unit1cthe die receivers4a,4bare built with the slots, grooves or recesses51and the through bores52.

The crimp unit1daccording toFIG. 14comprises significantly increased dimensions in the y-direction so that this crimp unit1dmight be used for holding die halves5,6with increased dimensions. For the crimp unit1dthe die receivers4a,4bare in a first approximation built by a block-like receiving space53. The receiving spaces53are each open in the direction of the x-axis. The walls opposite to the opening comprise recesses or grooves54. The recesses or grooves54receive protrusions or rips being formed at the front surface of the die halves5,6. Preferably the die halves5,6are held by frictional lock between the protrusions or rips and the recesses or grooves54in the die receivers4a,4b. For the embodiment shown inFIG. 14the die holders2,3are built by two parts with a base body55and a holding body56. The receiving spaces53a,53bare limited by the base body55and by the holding body56(wherein the transition from the base body55to the holding body56is located approximately in the middle of the receiving spaces53a,53b). The surfaces limiting the groove54and having a normal vector with an orientation parallel to the x-axis are limited both by the base body55and the holding body56. When inserting the holding body56into the base body55and pressing the holding body56towards the base body55(e.g. by screwing a screw) the lateral limiting surfaces of the grooves54a,54bof the holding body56are pressed towards the opposing limiting surfaces of the grooves54a,54bbeing built by the base body55a,55b. This leads to a clamping of the protrusions or rips of the die halves5,6in the grooves54. In the region of the holding body56limiting the receiving spaces53the holding body56has a U-shape in a section in the x-y-plane. The ends of the parallel side legs of the U limits the grooves54a,54b. It is also possible that the transverse leg of the U also extends beyond the side legs for providing a fixation region for a screw between the base body55and the holding body56(screw not shown inFIG. 14).

FIG. 15shows a crimp unit1aofFIG. 11with an additional protective cover57a. The protective cover57ais in a first approximation a hollow block with constant wall thickness. The hollow block is open at the bottom and ceiling so that the die holders2,3might enter from the upper side and from the lower side into the protective cover57a. By the handling means34extending through bores of the protective cover57athe protective cover57ais fixed at the die holder3whereas during the crimping process a relative movement of the die holder2with respect to the protective cover57is allowed. The protective cover57amight also have plates58extending along the x-y-axis. The plates58build handling surfaces. The protective cover57acomprises approximately rectangular recesses59in the walls extending in the y-z-plane. It is possible that during the crimping process a work piece (in particular the plug with the cable) extends through these recesses59into the crimp unit. The protective cover57ais built by a transparent plastic material so that it is possible that before, during and/or after the crimping process the operator inspects the die halves5,6and the work piece through the transparent material of the protective cover57awith a viewing direction parallel to the y-axis.

The protective covers57might differ in their design for the different crimp units1a-1d. As an exampleFIG. 16shows a protective cover57dusable for the crimp unit1daccording toFIG. 14. The size of the hollow block of the protective cover57dis adapted to the increased dimension of the crimp unit1dalong the x-axis. Instead of two rectangular recesses59as shown inFIG. 15only one single recess59is provided. The recess59is in this case built by two circular recesses60of the walls having an extension in the y-z-plane. The two circular recesses60are linked by a slot61extending in an x-y-axis along the circumference of the protective cover57d.

According toFIG. 17the die halves5,6used in a crimp unit1might comprise a plurality of nests62a-dlocated one besides another along the y-axis. The nests62a-dmight e.g. differ in size, contour or geometry. InFIG. 17the sensor14is indicated by a symbol. The sensor14is located centrally to the die halves5,6when seen along the crimping axis11. In case that a work piece is crimped in the central nest62c, the sensor14is located centrally and behind the crimping nest62cwhen seen along the crimping axis11. Accordingly, a major part of the crimp force13passes the sensor14. The die holders2,3as well as the sensor14are biased by symmetrical forces and tensions. Instead, when using the nests62a,62b,62dthe die holders2,3are biased by asymmetric forces and tensions. Only a reduced component of the crimping force passes the sensor. This reduced component might be considered by a modified calibration factor.

FIG. 18shows the use of the crimp unit1awith different die halves5,6. In these die halves5,6only three nests62a-care provided having different die contours.

According toFIGS. 19 and 20the crimp unit1might (permanently or optionally) be provided with a locator. The base design, degrees of freedom and function as well as the interaction of the locator with the work piece and the fixation of the locator at the die holders is e.g. described in the patent application DE 10 2010 061 148 A1 and further documents cited in this patent application. As an exampleFIGS. 19 and 20show a locator28in a type of explosional view. A base body63is fixed at the die holder3. A pivoting body64is held by a pivoting bolt29at the base body63. The pivoting bolt29defines the pivoting axis30. The pivoting body64comprises a bore. The pivoting bolt29in the assembled state extends through this bore.

In the state shown inFIG. 20the holding unit33is closed so that the work piece is held and fixed in the locator with a predetermined position and orientation. Furthermore, the pivoting body64is pivoted around the pivoting axis32from an open state into a closed state. By means of this pivoting movement the work piece is brought into a predetermined position and orientation with respect to the die halves5,6. The pivoting state of the pivoting body is secured by one, preferably two redundant fixation devices. According to the shown embodiment the base body63and the pivoting body64comprise magnetic elements65,66building the fixation device. The magnetic elements65,66hold the pivoting body in the state shown inFIG. 20. Preferably the magnetic elements65,66contact each other in the pivoting state according toFIG. 20. Furthermore, a securing element67for a redundant fixation might be provided.

FIG. 21schematically shows the flow of energy and signals in the crimp unit1. The sensor14is provided with electrical energy via a plug or an interface18. The output signal68of the sensor14correlating with a predetermined characteristic or dependency on the crimping force13is supplied or fed to a control unit69integrated into the crimp unit1. In the control unit69a modified output signal70is determined which is then supplied to the plug or interface18. The modified output signal70might be calculated from the output signal68by a constant calibration factor or a calibration curve (or on the basis of any different dependency). The calibration factor72or calibration curve73might be stored in a storage unit71. The control unit69reads the calibration factor72or calibration curve73from the storage unit71. The calibration factor72or the calibration curve73might be stored in the storage unit71at the manufacturer. However, it is also possible that the calibration factor72or the calibration curve73is considered and programmed in the control logic of the control unit69. It is also possible that with the startup of the crimping machine8an individual calibration process is run for determining and storing the calibration factor72, the calibration curve73or any other dependency which is then stored in the storage unit71. Furthermore, it is possible that different calibration factors72or calibration curves73are used for operating the nests62a,62b,62c,62d. Also for different crimp units1a,1b,1c,1ddifferent calibration factors72, calibration curve73or other dependencies might be used. The modified output signal70is then transmitted to a respective interface75of an adjacent element via the plug or interface18for further processing and/or for documentation purposes. In particular the adjacent element builds a part of the crimping machine8.

For a modified embodiment shown inFIG. 22the control unit69and the storage unit71are built externally from the crimp unit1. These elements might be located at any position of the crimping machine8. Preferably the storage unit71and the control unit69build a singular unit with one housing or with at least two modules. According toFIG. 22it is possible to transfer the output signal68of the sensor directly to a plug or a interface18. The plug or interface18cooperates with a respective plug or interface75for transferring the output signal68to the control unit69. In the control unit69the output signal68is processed to a modified output signal70under use of the calibration factor72, the calibration curve73or any other dependency.

In the specification related with the figures the letter a is added to the reference numerals to denote crimp units1of differing design, in particular with respect to the design of the die receivers4and/or the coupling regions7. In other cases the letters a and b have been used in order to distinguish constructive elements having corresponding functions, wherein constructive elements associated with the die holder2are denoted with the letter a, whereas constructive elements associated with the die holder3are denoted with the letter b.

A “set of interchangeable crimp units” means at least two crimp units designated for one and the same crimping machine. It is possible to disassemble a first one of the crimp units of the set from the crimping machine and to replace the first crimp unit with a second one of the crimp units of the set.