Device for connecting a contact element to a conductor and method

Abstract

The invention relates to a device for connecting a contact element to a conductor and a corresponding method. The device comprises a receiving area (A) for positioning the contact element and the conductor, several punches (30, 30'; 31-31'''; 32, 32'; 33, 33') arranged around the receiving area (A) such that the punches (30, 30'; 31-31'''; 32, 32'; 33, 33') can attach the contact element to the conductor, and further, at least one sensor (40-40''') arranged on one of the punches for determining a force curve or force values. With such a device and such a method, a contact element, in particular a sleeve-shaped one, can be attached to a conductor, in particular by crimping.

Description

Technical field

[0001] The invention relates to a device for connecting a contact element to a conductor and a method for connecting a contact element to a conductor. With such a device and such a method, a contact element, in particular a sleeve-shaped one, can be attached to a conductor, in particular by crimping. State of the art

[0002] Devices for connecting a contact element to a conductor are known in various designs. Contact elements can have different shapes. For example, they can be sleeve-shaped, in which case the conductor is inserted into the opening of the contact element to create a connection and is subsequently crimped onto the conductor by one or more crimping dies.

[0003] DE 42 40 498 A1 describes a device for connecting a wire to a contact element or the like by deforming clamping parts of the contact element by means of pressure elements, in particular pressure elements of a crimping tool with a crimping die, which is interchangeably arranged in a stop press and performs the deformation in a crimping position. To create several deformation areas on the contact element, a number of crimping dies corresponding to their arrangement are arranged around a receiving opening.

[0004] Furthermore, document DE 195 20 928 A1 is known. It describes a device for connecting a wire to a contact element by deforming a clamping area of ​​the contact element using a plurality of crimping dies that can be moved relative to each other into a crimping position. In the deformed state, the clamping area has the shape of a polygon in the cross-sectional direction of the wire. Outer surface sections of the crimping dies are designed such that, in the crimping position, they enclose the clamping area to form the polygon, and at least one outer surface section of a first crimping die is extended in a straight or slightly angled manner relative to one side of the polygon such that, in the crimping position, this extended outer surface section overlaps a section of a second crimping die in a contacting manner.

[0005] Although the aforementioned devices have proven their worth in operation, there are increased requirements for quality control of the products manufactured with such a device. Description of the invention

[0006] The invention aims to provide a device for connecting a contact element to a conductor, thereby further increasing reliability in manufacturing. Furthermore, a corresponding method is required.

[0007] Claim 1 provides a solution for this. In particular, the invention solves this problem by providing at least one sensor that is arranged on a die for (directly or indirectly) determining a force curve, in particular a crimping force curve, or force values. This enables direct and immediate monitoring of the processing operation, especially the crimping operation, so that defective parts can be reliably detected and sorted out. Consequently, a very high level of manufacturing quality can be reliably ensured.

[0008] In particular, the invention provides a device for connecting a contact element, preferably sleeve-shaped, to a conductor, wherein the device comprises: a receiving area for positioning the contact element and the conductor, several punches, in particular crimp punches, which are arranged around the receiving area in such a way that the punches can attach the contact element to the conductor, and at least one sensor which is arranged on one of the punches for (direct or indirect) determination of a force curve, in particular a crimp force curve, or individual force values.

[0009] In this way, changes during the processing operation, particularly the crimping process, such as uneven wear of the guide or a die, an asymmetrical position of the contact element relative to the dies, or an asymmetrical design of the contact element, can be reliably detected. Positioning the sensor on the die ensures detection in close proximity to the crimping point. Any process variations that lead to changes in the crimping force can be more easily detected through the optimized crimping force measurement, especially the optimized measuring point.

[0010] The device according to the invention enables optimization in the processing of contact elements, particularly sleeve-shaped contact elements, in tools. It has been found that sleeve-shaped contact elements, in particular, exhibit poorer headroom compared to other mass-produced contacts made of stamped sheet metal. Headroom refers to the difference between the maximum values ​​of a good crimp connection and a crimp where the conductor strands are not fully engaged, resulting in an empty crimp. The requirement is that the strands are fully engaged and that a maximum deviation of only a few percent of missing strands is acceptable. In practice, this can lead to a missing strand, depending on the conductor's cross-section.

[0011] Additional influences, for example from other mechanically moving components during the crimping process, would negatively affect detection. The invention thus ensures that the additional mechanical influences present in such tools, which do not affect the product, are largely eliminated during quality control.

[0012] It is preferred that at least four crimps are arranged around the receiving area. A so-called 4-point crimp has proven particularly advantageous for sleeve-shaped contact elements. However, more or fewer than four crimps, for example three or six crimps, can also be provided.

[0013] The punches can be arranged in an orientation inclined to the vertical direction, particularly if the device comprises four punches. The punches are preferably arranged in a star shape around the receiving area.

[0014] The stamps can be arranged in an even distribution around the receiving area. In particular, if four stamps are used, they form a V-arrangement with a 90-degree offset.

[0015] According to a preferred embodiment, an evaluation unit is provided which is connected to the sensor, wherein the evaluation unit is configured to evaluate the force curve or individual (specific) force values ​​in the force curve, as well as local or absolute maxima or minima in height and position, during a processing operation, in particular a crimping operation.

[0016] In particular, the evaluation unit is configured to generate an error message if there is a defined deviation from a target force curve. The corresponding (crimp) product can then be removed as scrap.

[0017] According to one embodiment, the punch, or at least one of the punches, has a first punch section and a second punch section, and the sensor is arranged between the first and second punch sections. This allows for extremely precise detection by the sensor in close proximity to the point of compression, particularly crimping. The punch is preferably designed as a multi-part structure, comprising the first and second punch sections.

[0018] According to a further embodiment, the at least one punch has one or more weakened areas. When a force is applied, such as that generated when the contact element is pressed onto the conductor, the weakened area(s) cause a defined deformation of the punch. The sensor can detect the force resulting from this deformation of the punch directly or indirectly.

[0019] According to one embodiment, the sensor is arranged on a surface of the stamp, for example, by being glued on. In particular, the sensor in this embodiment is a strain gauge.

[0020] It is preferred that several sensors are provided, with one sensor arranged on each punch. For example, if the device comprises four punches, sensors can be attached to two, three, or all punches.

[0021] According to one embodiment, the sensor in question is designed as a force sensor. The force sensor is positioned on the piston in such a way that it is located in the direct path of the force or in the area where a force is applied to the piston.

[0022] According to another embodiment, the sensor in question is designed as a strain sensor, in particular as a strain gauge. A strain sensor is attached, preferably glued, to a surface of the punch.

[0023] According to one embodiment, the device has an adjustment mechanism, in particular in the form of a rotary head, which can be driven by a press ram. The press stroke transmitted from the press ram to the rotary head actuates the device and thus performs a crimping operation. The adjustability allows the actuation stroke of the device to be set, which in turn alters the crimping action.

[0024] It is preferred that each punch is associated with a return mechanism, in particular a spring. The return mechanism provides a kind of energy storage device and serves to guide a pressure jaw. The return mechanism, in particular a coil spring, can be arranged around a locking pin.

[0025] According to a further aspect of the invention, a method for connecting a contact element to a conductor is provided, comprising the steps of: positioning the contact element and the conductor in a receiving area and moving several punches to the receiving area to attach a contact element to the conductor, in particular by pressing it on, wherein at least one sensor is provided which is arranged on one of the punches for (directly or indirectly) determining a force curve or force values. Regarding the advantages, reference is made to the explanations of the device. Within the scope of the method, a device according to any of the aforementioned aspects can be used.

[0026] The conductor in question is, in particular, an electrical conductor comprising strands with which the contact element is crimped. According to another embodiment, the conductor can be an optical fiber. In this case, the contact element can be designed as a metal sleeve (contact with an internal thread). Brief description of the drawings

[0027] The invention is described below by way of example with reference to the attached figures. Fig. 1 shows a view of a crimping tool according to a first embodiment of the invention, wherein the crimping tool is mounted in a stop press. Fig. 2 shows the crimping tool according to the first embodiment. Fig. 3 shows components of the crimping tool according to the first embodiment. Fig. 4 shows components of a crimping tool according to a second embodiment. Fig. 5 shows components of a crimping tool according to a third embodiment. Fig. 6 shows components of a crimping tool according to a fourth embodiment. Description of embodiments

[0028] Preferred embodiments of the invention are illustrated by way of example with reference to the accompanying figures. Individual features of the embodiments described below can each be used individually to specify the invention. Furthermore, additional embodiments are developed by combining individual features of the embodiments described below.

[0029] In particular, in Fig. 1 A stop press 100 is shown, in which a crimping tool 10 according to a first embodiment is received. The crimping tool 10 is an embodiment of a device for connecting a contact element to a conductor. A press ram 110 of the stop press 100 is provided for actuating the crimping tool 10 and can accordingly perform a movement in the vertical direction. If necessary, it is possible to exchange the crimping tool 10 and replace it with another crimping tool.

[0030] The crimping tool 10, as described in more detail below, is designed for connecting a contact element to a conductor. For this purpose, a sleeve-shaped contact element is arranged around a conductor, or an end section of the conductor is inserted into the sleeve-shaped contact element, and the contact element is crimped to the conductor from several sides. To carry out the crimping process, the contact element arranged around the conductor is positioned in a receiving area A.

[0031] Although crimping tools are described in the preferred embodiments which contribute to crimping a contact element onto the conductor from four sides, the invention also includes embodiments which are set up for crimping such contact elements on fewer or more than four areas of the contact element.

[0032] The conductor in question is, in particular, an electrical conductor comprising strands with which the contact element is crimped.

[0033] The in Fig. 2 The crimping tool 10, shown in more detail, comprises a housing 15, the housing 15 having a base plate 16, a front plate 17, and several side plates 18. A crimping die 19 is accommodated in the housing 15, which (in Fig. 2 (not shown) guides for several crimping dies (punches) 30-34 are provided. The crimping dies 30-34 are aligned at 90° angles to each other and arranged in a star shape around the receiving area A.

[0034] Furthermore, the crimping tool 10 comprises a pressure piece 20, which includes a transverse plate 21 arranged outside the housing 15, a first pressure plunger 22 extending into the housing 15, and a second pressure plunger 23 also extending into the housing 15. A rotary head 26 is provided on the transverse plate 21, which transmits the force applied by the press plunger 110 into the crimping tool 10, in particular the pressure piece 20 of the crimping tool 10. In this way, the pressure piece is moved in a vertical direction to carry out the crimping process.

[0035] The first die 22 comprises an upper pressure ramp 22a and a lower pressure ramp 22b. Force is transmitted via these pressure ramps to an upper pressure jaw 24a and a lower pressure jaw 24b, respectively, causing the pressure jaws 24a and 24b to move in a horizontal direction. The upper pressure jaw 24a engages with the first crimping die 30, and the lower pressure jaw 24b engages with the fourth crimping die 33, so that when the pressure jaws 24a and 24b move, the first crimping die 30 and the second crimping die 33 are moved relative to the receiving area A.

[0036] The second die 23 comprises an upper pressure ramp 23a and a lower pressure ramp 23b. Force is transmitted via these pressure ramps 23a and 23b to a corresponding upper pressure jaw 25a and a lower pressure jaw 25b, respectively, to move these pressure jaws 24a and 24b in a horizontal direction. The upper pressure jaw 25a engages with the second crimping die 31, and the lower pressure jaw 25b engages with the third crimping die 32.

[0037] The arrangement and actuation of the crimping dies 30-33 allows a contact element to be crimped onto a conductor in the receiving area A from four sides. The pressure jaws 24a, 24b, 25a, 25b are guided by locking pins 27 and returned from the crimping position by the spring 28 provided on each locking pin 27.

[0038] According to the first embodiment of the crimping tool 10, the second crimping die 31 is multi-part and comprises, in particular, a first crimping die section 31a and a second crimping die section 31b. A force sensor 40 is arranged between the first crimping die section 31a and the second crimping die section 31b. The force sensor 40 is configured to detect a force acting during a crimping operation, so that a crimping force curve can be recorded during the crimping operation. By arranging the force sensor 40 in the area of ​​the second crimping die 31, the forces acting during the crimping operation when pressing the contact element onto the conductor can be determined precisely.

[0039] Based on Fig. 4 A second embodiment of a crimping tool is described, similar to Figure 3For clarity, only components of the crimping tool are shown. Regarding components of the crimping tool and the stop press not shown, as well as further details, please refer to the explanations for the first embodiment.

[0040] In particular, the crimping tool according to the second embodiment comprises a pressure piece 20', which includes a transverse plate 21', a first pressure punch 22', and a second pressure punch 23'. The first pressure punch 22' comprises an upper pressure ramp 22a' and a lower pressure ramp 22b', via which force is transmitted to an upper pressure jaw 24a' and a lower pressure jaw 24b', respectively. The upper pressure jaw 24a' engages with the first crimping punch 30', and the lower pressure jaw 24b' engages with the fourth crimping punch 33', so that when the pressure jaws 24a' and 24b' are moved, the first crimping punch 30' and the second crimping punch 33' are moved relative to the receiving area A. The second printing die 23' comprises an upper printing slope 23a' and a lower printing slope 23b', via which force is transmitted to a corresponding upper printing jaw 25a' and a lower printing jaw 25b'.The upper pressure jaw 25a' is engaged with the second crimping die 31' and the lower pressure jaw 25b' is engaged with the third crimping die 32'.

[0041] The second embodiment of the crimping tool differs from that of the first embodiment in that all crimp dies 30-33` are multi-part. Thus, the first crimp die 30' comprises a first crimp die section 30a' and a second crimp die section 30b`, the second crimp die 31' comprises a first crimp die section 31a' and a second crimp die section 31b`, the third crimp die 32' comprises a third crimp die section 32a' and a second crimp die section 32b`, and the fourth crimp die 33' comprises a first crimp die section 33a' and a second crimp die section 33b'.

[0042] A force sensor 40' is arranged between the respective crimping die sections. Regarding the operating principle of the respective force sensor 40', reference is made to the explanations of the force sensor 40' according to the first embodiment.

[0043] Using multiple sensors at different positions allows for more precise detection of deviations and changes during the crimping process. This enables more accurate detection of asymmetrical forces or uneven deformations.

[0044] Fig. 5 Figure 1 shows a third embodiment of a crimping tool, whereby only certain components of the crimping tool are shown for clarity. For components not shown, the stop press, and further details, please refer to the explanations of the first and second embodiments.

[0045] In Fig. 5The printing element 20" is shown in a perspective view for illustration. The printing element 20" according to the third embodiment is essentially the same as that according to the first embodiment and comprises a transverse plate 21", a first printing die 22", and a second printing die 23". The first printing die 22" comprises an upper printing bevel 22a" and a lower printing bevel 22b", and the second printing die 23" comprises an upper printing bevel 23a" and a lower printing bevel 23b".

[0046] As explained using the first and second embodiments, pressure jaws are actuated via the pressure piece and the pressure ramps. Fig. 5 For illustrative purposes, only an upper pressure jaw 25a" is shown, which drives a second crimping die 31".

[0047] The crimping tool according to the third embodiment differs from that of the first embodiment essentially in that the second crimping die 31" is a single piece and designed as shown below.

[0048] In particular, the second crimping die 31" comprises an actuating section 31-1" and an extension section 31-2" extending therefrom. The extension section 31-2" terminates in a U-shaped area in which a force sensor 40" is accommodated. A weakening area 31-1a" is provided in the actuating section 31-1" and a weakening area 31-2a" is provided in the extension section 31-2", wherein the weakening areas 31-1a" and 31-2a" cause a corresponding deformation of the second crimping die 31" when a force is applied. Due to the deformation of the second crimping die 31", the force sensor 40" can detect the force, so that a crimping force curve can be recorded when the crimping tool is actuated.

[0049] Fig. 6 A fourth embodiment of a crimping tool is shown, similar to the illustrations in the Figures 3-5For clarity, only components of the crimping tool according to the fourth embodiment are shown.

[0050] In particular, the crimping tool according to the fourth embodiment comprises a pressure piece 20", which is designed similarly to those of the first to third embodiments.

[0051] In particular, the printing piece 20‴ comprises a transverse plate 21‴, a first printing die 22‴ and a second printing die 23‴. The first printing die 22‴ comprises an upper printing bevel 22a‴ and a lower printing bevel 22b‴, and the second printing die 23‴ comprises an upper printing bevel 23a‴ and a lower printing bevel 23b‴.

[0052] As explained with reference to the first, second and third embodiments, pressure jaws are actuated via the pressure piece 20‴ and its pressure ramps. Fig. 6For illustrative purposes, only an upper pressure jaw 25a‴ is shown, with which a second crimping die 31‴ is driven.

[0053] The crimping tool according to the fourth embodiment differs essentially from that of the first embodiment in that the second crimping die 31‴ is made in one piece. Furthermore, a strain gauge 40‴ is arranged on a surface of the crimping die to detect deformation of the second crimping die 31‴ during a crimping process.

[0054] The described crimping press 100 has an evaluation unit (not shown) that is connected to the sensor (40-40‴) according to the respective embodiment. Based on the data acquired by the respective sensor during a crimping process, the evaluation unit can analyze a crimping force curve. In the event of a defined deviation from a target curve, corrective actions can be taken, such as removing the product manufactured with this crimping process as scrap from the production process. Otherwise, for so-called "good" parts, appropriate documentation can be created, which a user of the crimping tool can save as proof of production quality.

[0055] Although the invention was described using an electrical conductor, it is also possible that the conductor is an optical fiber, for example, a plastic optical fiber. As a purely exemplary repair solution, a metal sleeve (contact with an internal thread) can be attached to the optical fiber, which is done using such a crimping tool by pressing "grooves" into the optical fiber sheath.

Claims

1. Device for connecting a contact element to a conductor, comprising: a receiving area (A) for positioning the contact element and the conductor, several punches (30, 30'; 31-31‴; 32, 32'; 33, 33') arranged around the receiving area (A) such that the punches (30, 30'; 31-31‴; 32, 32'; 33, 33') can secure the contact element to the conductor, further comprising at least one sensor (40-40‴) arranged on one of the punches for determining a force curve or force values.

2. Device according to claim 1, wherein at least four punches are arranged around the receiving area, wherein it is preferred that the punches are arranged in an orientation inclined to the vertical direction.

3. Device according to one of the preceding claims, wherein the punches are arranged in a uniform distribution around the receiving area (A).

4. Device according to one of the preceding claims, further comprising at least one evaluation unit connected to the sensor (40-40‴), wherein the evaluation unit is configured to evaluate the force curve or force values ​​during a processing operation.

5. Device according to claim 4, wherein the evaluation unit is configured to generate an error message in the event of a defined deviation from a target curve of the force curve.

6. Device according to one of the preceding claims, wherein the or at least one of the punches has a first punch section (31a; 30a', 31a', 32a', 33a') and a second punch section (31b; 30b', 31b', 32b', 33b') and the sensor (40, 40') is arranged between the first punch section (31a; 30a', 31a', 32a', 33a') and the second punch section (31b; 30b', 31b', 32b', 33b').

7. Device according to one of claims 1-5, wherein the at least one punch (31") has one or more weakening areas (31-1a'', 31-2a'') and the sensor (40'') detects a force resulting from a deformation of the punch (31").

8. Device according to one of the preceding claims, wherein the sensor (40‴) is arranged on a surface of the punch (31‴).

9. Device according to one of the preceding claims, comprising several sensors (40-40‴), wherein one sensor is arranged on each punch.

10. Device according to one of the preceding claims, wherein the sensor is a force sensor (40-40'') or a strain sensor (40‴).

11. Device according to one of the preceding claims, further comprising an adjusting device, in particular a rotary head (26) which can be driven by a press ram (110).

12. Device according to one of the preceding claims, wherein each punch is associated with a return device (28), in particular a spring.

13. Method for connecting a contact element to a conductor, comprising: positioning the contact element and the conductor in a receiving area (A), moving several punches (30, 30'; 31-31‴; 32, 32'; 33, 33') to the receiving area for attaching the contact element to the conductor, wherein at least one sensor (40-40‴) is provided which is arranged to determine a force curve or force values ​​on one of the punches (30, 30'; 31-31‴; 32, 32'; 33, 33').

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