This application claims priority to co-pending German Patent Application No. DE 10 2012 107 467.4 entitled “Wechseladapter für eine Crimpmaschine”, filed Aug. 15, 2012.
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.
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.
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.
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.
Other features and advantages of the present invention will become apparent to one with skill in the art upon examination of the following drawings and the detailed description. It is intended that all such additional features and advantages be included herein within the scope of the present invention, as defined by the claims.
The invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. In the drawings, like reference numerals designate corresponding parts throughout the several views.
A sensor 14 is integrated into the crimp unit 1.
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As shown in the sectional view of
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The crimp unit 1d according to
The protective covers 57 might differ in their design for the different crimp units 1a-1d. As an example
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In the state shown in
For a modified embodiment shown in
In the specification related with the figures the letter a is added to the reference numerals to denote crimp units 1 of differing design, in particular with respect to the design of the die receivers 4 and/or the coupling regions 7. 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 holder 2 are denoted with the letter a, whereas constructive elements associated with the die holder 3 are 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.
Many variations and modifications may be made to the preferred embodiments of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of the present invention, as defined by the following claims.
Number | Date | Country | Kind |
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10 2012 107 467.4 | Aug 2012 | DE | national |