DEVICE AND METHOD FOR TESTING AN EXTERNAL CONDUCTOR CONTACT

Description

Technical field

[0001] The invention relates to a device and a method for testing an outer conductor contact, wherein the test preferably comprises an electrical test and the method preferably runs automatically. State of the art

[0002] During the manufacture of outer conductor contacts, particularly those used for coaxial cable assembly, it can happen that material does not completely detach from the surface due to severe deformation during the punching process. This material then often forms chips or fine hairs, which can later cause an unwanted short circuit in a fully assembled connector system. To prevent such short circuits, the chips or hairs must be located and removed.

[0003] In the current state of the art, electrical testing procedures are performed on the fully assembled (coaxial) cables. In particular, a specified voltage of, for example, 500 V is applied to the inner conductor contact in coaxial cables to detect flashover to the outer conductor contact caused by electrically conductive foreign bodies between the inner and outer conductor contacts. However, since these testing procedures only take place at the end of the assembly process, a defective cable is only then recognized as such and declared as scrap.

[0004] Alternatively, current technology involves optically inspecting outer conductor contacts after their manufacturing or assembly process on a cable. However, depending on their location and appearance, foreign matter or short circuits cannot be reliably detected during optical inspections.

[0005] Relevant prior art is published in US 2020 / 072890 A1. Description of the invention

[0006] It is therefore an object of the present invention to provide an apparatus and a method for effectively testing outer conductor contacts in order to reduce rejects.

[0007] The above-mentioned object is achieved by a device according to claim 1 and a method according to claim 6. Further advantageous embodiments of the invention can be found in the subclaims, the description and the drawings.

[0008] In particular, the above-mentioned object is achieved by a device for testing an outer conductor contact comprising a guide with a feed for providing a carrier strip with outer conductor contacts at a fixing region, a fixing device for fixing an outer conductor contact to be tested at the fixing region, and a test pin which can be at least partially inserted into the outer conductor contact and generates a predetermined electric field so that electrically conductive foreign bodies located within the outer conductor contact cause a short circuit.

[0009] This device makes it possible to easily and reliably test outer conductor contacts before assembly on a cable. By testing before assembly, a defective outer conductor contact can be identified and excluded from further processing or assembly. This saves time and resources and reduces the amount of scrap on pre-assembled cables. The test is preferably carried out with regard to foreign bodies located inside the outer conductor, which could lead to an unwanted short circuit when the outer conductor is later used in a connector. This device also detects foreign bodies such as fine metallic hairs or shavings, which are sometimes hidden behind other components in the outer conductor contact, for example an insulator, and could lead to a short circuit when used later.

[0010] Preferably, the electric field is generated by a voltage across the test pin in the range of 100–1000 V, more preferably in the range of 200–900 V, even more preferably in the range of 300–800 V, and most preferably in the range of 400–700 V. Voltages above 1000 V require special safety measures, requiring a more complex device design. Therefore, it is desirable to test in a voltage range up to 1000 V. Furthermore, tests have shown that the lower the voltage used for testing, the fewer false positives occur.

[0011] Preferably, the maximum diameter of the test pin relative to the outer conductor contact is selected such that the sum of the maximum diameter of the test pin and twice the minimum clearance is smaller than the inner diameter of the outer conductor contact. If an electrically conductive object, or even the outer conductor contact itself, is located within the minimum clearance of the test pin, a short circuit will occur. One way to prevent an unwanted short circuit between the outer conductor contact and the test pin is to fulfill the aforementioned condition. This ensures that only foreign bodies within the outer conductor contact, and not the outer conductor contact itself, cause a short circuit.

[0012] Preferably, the minimum clearance is determined from a table at a predetermined degree of contamination. The minimum clearances depending on the voltage applied to the test pin are known and can be easily determined using tables. Should the testing and / or operating conditions for an outer conductor contact or connector change, this can be taken into account accordingly using the table entries.

[0013] A short circuit is preferably triggered by foreign bodies such as at least partially detached particles from the inner surface of the outer conductor contact. This has the advantage that metallic chips, threads, and / or flakes, which occur during the production of the outer conductor contact and which often still adhere to the inner surface of the outer conductor contact, can be detected. This detection allows the affected outer conductor contact to be marked as reject and excluded from further assembly, thus preventing a subsequent short circuit in a pre-assembled cable.

[0014] The above-mentioned object is further achieved in particular by a method for testing an outer conductor contact, the method comprising the following steps: providing an outer conductor contact at a fixing region, fixing the outer conductor contact to the fixing region, inserting a test pin at least partially into the outer conductor contact, the test pin having no voltage, applying a voltage to the test pin, and checking whether a short circuit has occurred between the test pin and at least one electrically conductive foreign body that may be located within the outer conductor contact.

[0015] This method has the advantage that it can be implemented automatically. Furthermore, handling the outer conductor contacts on a carrier strip is easier with this method than handling a pre-assembled cable. If an outer conductor contact is identified as defective, it can simply be separated from the carrier strip after testing and is no longer available for subsequent assembly. This makes testing, and in particular the subsequent assembly of a cable, much more effective than with prior art methods.

[0016] This process is preferably performed before the outer conductor contact is assembled on a cable. Testing the outer conductor contacts before assembly on a cable has the advantage of identifying rejects early and eliminating unnecessary assembly. This approach saves time and resources.

[0017] Preferably, the test pin is inserted until it stops at an insulator located inside the outer conductor contact. By inserting the test pin up to the insulator, the entire area that is (later) relevant for a short circuit (between the inner and outer conductor contacts) is tested. However, the test pin is not inserted further into the outer conductor contact than necessary, because in the insulator area, any foreign body is hidden by the insulator and would not lead to a short circuit. By only testing after an insulator has been installed in the outer conductor contact, rejects are reduced. This occurs when foreign bodies appear on the inner surface of the outer conductor contact but are (completely) hidden by the insulator. The test procedure itself is independent of whether an insulator is already installed in the outer conductor contact or not.

[0018] Preferably, testing is performed using an electrical measurement and / or an optical measurement. Electrical and optical measurements are independent measurement methods. Using both measurement methods simultaneously allows for redundant measurements. Redundant measurements can increase measurement reliability. Optical measurements can be simpler in design, while electrical measurements can be more accurate.

[0019] Preferably, the fixing is achieved by force and / or form locking using a fixing device. Force and / or form locking are simple ways to securely fix an outer conductor contact under test. The form locking can be directly adapted to a specific outer conductor contact and prevents the outer conductor contact from slipping.

[0020] The following description of embodiments is made with reference to the accompanying figures. Fig. 1 is a perspective view of an embodiment of a system for testing an outer conductor contact; Fig. 2 is a detailed view of Fig. 1 ; Fig. 3 the detailed view of Fig. 2 with fixed outer conductor; Fig. 4 the detailed view of Fig. 3 with inserted test pin; Fig. 5 a perspective view of an embodiment of an outer conductor contact with inserted test pin; and Fig. 6 a cross-sectional view of the illustration from Fig. 5 .

[0021] In the following, preferred embodiments are described in detail with reference to the accompanying figures.

[0022] Fig. 1shows an embodiment of a device 1 for testing an outer conductor contact 2. The device 1 shown has at least one guide 6 with a feed for providing a carrier strip 4 with outer conductor contacts 2 at a fixing area 7. The carrier strip 4 can be provided from a storage device, such as a carrier strip roll. The fixing area 7 is the area on the device 1 at or in which an outer conductor contact 2 to be tested is fixed and then tested.

[0023] The device 1 further comprises a fixing device 8 for fixing an outer conductor contact 2 to be tested to the fixing area 7. The Figures 1 -4The fixing device 8 shown comprises at least one holding-down device. Furthermore, the fixing device 8 can comprise a support 9, onto which the outer conductor contact 2 to be tested is placed and subsequently fixed. Preferably, the outer conductor contact 2 to be tested is clamped between the holding-down device 8 and the support 9 during fixing. Due to the clamped mounting, the outer conductor contact 2 to be tested is securely mounted and prevented from moving during the test.

[0024] The device 1 further comprises a test pin 10, which can be at least partially inserted into the outer conductor contact 2 (see Fig. 5 ). The Figs. 1 - 4The test pin 10 shown is preferably mounted in a holder 12 and is interchangeable. Thus, depending on the outer conductor contact 2 to be tested, different test pins 10, i.e., in particular with different maximum diameters D1, can be used on the device 1. The holder 12 is preferably mounted on a displaceable base 14. By displacing the base 14 toward and away from the fixing area 7, the test pin 10, in particular with its test tip 11, can be moved onto or into the outer conductor contact 2 to be tested. The base 14 can be moved, for example, via an actuator.

[0025] A predetermined voltage can be applied to the test pin 10, causing the test pin 10 to generate a predetermined electric field. The electric field is generated by a voltage at the test pin 10 in the range of 100–1000 V, more preferably in the range of 200–900 V, even more preferably in the range of 300–800 V, and most preferably in the range of 400–700 V. Due to the generated electric field, electrically conductive foreign bodies located within the outer conductor contact 2 cause a short circuit. This short circuit can be detected, thus providing information about foreign bodies in the outer conductor contact 2. If no short circuit occurs, the outer conductor contact 2 is classified as "good" and can be further processed. If a short circuit is detected, the tested outer conductor contact 2 is classified as "bad" or scrap and marked and / or further processed accordingly.In practice, a short circuit is primarily caused by foreign matter such as at least partially detached particles from the inner surface of the outer conductor contact. These at least partially detached particles can include flakes, chips, or fine hairs, which are usually still attached to one end of the inner surface of the outer conductor contact.

[0026] The test pin 10 has a maximum diameter D1, which is present in particular at the test tip 11. The maximum diameter D1 of the test pin 10 is selected with respect to the outer conductor contact 2 such that the sum of the maximum diameter D1 of the test pin 10 and twice the minimum clearance is smaller than the inner diameter D2 of the outer conductor contact 2 (see Fig. 6). In practice, maximum diameters D1 of the test pin 10 in the range of 1 - 2 mm, preferably in the range of 1.3 - 1.8 mm, are used. The simple minimum air gap designates a distance from the test pin 10 at which the electric field is so strong that an electrical body causes a flashover or short circuit to the test pin 10. Figuratively speaking, the simple minimum air gap surrounds the test pin 10 like an aura. In terms of diameter, one considers twice the minimum air gap, i.e. a simple minimum air gap on both sides of the test pin 10. Within this aura, which acts like an enlarged outer circumference of the test pin 10, the electric field of the test pin is so strong that all electrically conductive bodies located within the aura or minimum air gap cause a flashover or short circuit. The minimum air gap is preferably determined from a table at a predetermined degree of contamination.In practice, the minimum air distance can be determined from the standard VDE 0110-1 / 4.97 with a pollution degree of 1 - 4.

[0027] Figures 2 - 4 show an embodiment of the method for testing an outer conductor contact 2. The method is preferably carried out before the outer conductor contact 2 is assembled onto a cable. The method is particularly suitable for automated testing of outer conductor contacts 2. The method comprises at least the following steps:

[0028] In a first step, an outer conductor contact 2 to be tested is provided at the fixing area 7 (see Fig. 2). For provision, the carrier strip 4 is moved in a feed direction X with the aid of the feed and the guide 6, so that each outer conductor contact 2 on the carrier strip 4 is arranged individually on the fixing area 7 one after the other. In the illustrated embodiment, the outer conductor contact 2 to be tested is placed on a support 9 on the fixing area 7. The test pin 10 is held in the holder 12 and is arranged at a distance from the outer conductor contact 2.

[0029] After provision, the outer conductor contact 2 is fixed to the fixing area 7. The fixing can be carried out by force and / or form closure with the aid of a fixing device 8. One embodiment of the fixing is shown in Fig. 3shown. In this embodiment, for fixing purposes, a hold-down device 8 moves along a third direction Z toward the outer conductor contact 2 and clamps the outer conductor contact 2 between itself and the support 9. The test pin 10 is still arranged at a distance from the outer conductor contact 2. In an alternative embodiment, the test pin 10 can be moved simultaneously or with a time delay with the movement of the hold-down device 8 along a second direction Y toward the outer conductor contact 2.

[0030] After the outer conductor contact 2 to be tested has been fixed in place, the test pin 10 is inserted at least partially into the outer conductor contact 2. The insertion preferably takes place via an opening 3 on the outer conductor contact 2, which is located on the future cable outgoing side, over which an inner conductor contact will later also be inserted. Later here means in a subsequent step or steps of the cable assembly. During insertion, the test pin 10 is not live. Although in practice the outer conductor contact 2 is aligned with its central axis M such that the test pin 10 moves in or out of the outer conductor contact 2 along this central axis M, the test pin 10 is nevertheless only energized when the test pin 10 has reached its end position in the outer conductor contact 2 in order to avoid unwanted short circuits due to an oblique movement. The end position can be freely selected.Preferably, the test pin 10 is inserted until it stops on an insulator 5 which is arranged within the outer conductor contact 2 (see . Fig. 6 ). The insulator 5 may already be arranged in the outer conductor contact 2 prior to the method described here. The test pin 10 is preferably spring-mounted in the holder 12 to prevent damage to the outer conductor contact 2 and / or the test pin 10.

[0031] After the test pin 10 is positioned in its final position in the outer conductor contact 2, a voltage is applied to the test pin 10. The voltage comprises a predetermined voltage value. Studies have shown that the number of false positives can be significantly reduced if a lower voltage is used, in particular significantly below 1000 V. The aim is to use a voltage in the range of 550 V - 650 V.

[0032] While a voltage is applied to the test pin 10, a test is performed to determine whether a short circuit has occurred between the test pin 10 and at least one electrically conductive foreign body that may be located within the outer conductor contact 2. The test can be performed by an electrical measurement and / or an optical measurement. During an electrical measurement, a voltage drop between the test pin 10 and the outer conductor contact 2 is detected by means of an electrical discharge. For the electrical measuring method, the test pin 10 and the outer conductor contact 2 must be connected to a measuring device via measuring contacts. Optionally, instead of connecting the outer conductor contact 2 to a measuring contact, the support 9, if it is made of an electrically conductive material, can be connected to the measuring contact.Regardless of the electrical measurement method, a short circuit can also be detected optically, as a brief flash of light occurs during a short circuit. Using an optical measuring device / method, a flash of light within the outer conductor contact 2 can be detected and interpreted as a short circuit. The optical measurement method has the advantage over the electrical measurement method that it is contact-free.

[0033] If a short circuit occurs during testing, the outer conductor contact 2 is declared as defective. This outer conductor contact 2 can then be marked accordingly and / or separated from the carrier strip 4 in a subsequent processing step. After the defective outer conductor contact 2 has been separated, the carrier strip 4 can then be rewound onto a carrier strip reel, for example, with the carrier strip 4 then only containing the outer conductor contacts 2 declared as "good goods." LIST OF REFERENCE SYMBOLS

[0034] 1Device 2Outer conductor contact 3Opening 4Carrier strip 5Insulator 6Guide 7Fixing area 8Fixing device 9Support 10Test pin 11Test tip 12Holder 14Base D1Maximum diameter D2Inner diameter MCenter axis XFeed direction YSecond direction ZThird direction

Claims

1. Apparatus (1) for testing an outer conductor contact (2), comprising: a) a guide (6) having a feed for providing at a fixing area (7) a carrier strip (4) having outer conductor contacts (2); b) a fixing apparatus (8) for fixing an outer conductor contact (2) that is to be tested to the fixing area (7); characterized by c) a test pin (10) which can be inserted at least partially into the outer conductor contact (2) and is designed to generate a predetermined electric field so that electrically conductive foreign bodies located within the outer conductor contact (2) cause a short circuit.

2. Apparatus (1) according to Claim 1, in which the electric field is generated by a voltage across the test pin (10) in the range of 100-1000 V, more preferably in the range of 200-900 V, even more preferably in the range of 300-800 V, and most preferably in the range of 400-700 V.

3. Apparatus (1) according to Claim 1 or 2, in which a maximum diameter (D1) of the test pin (10) with respect to the outer conductor contact (2) is selected such that a sum of the maximum diameter (D1) of the test pin (10) and a doubled minimum air gap is smaller than an inner diameter (D2) of the outer conductor contact (2).

4. Apparatus (1) according to Claim 3, in which the minimum air gap is determined tabularly for a predetermined degree of pollution.

5. Apparatus (1) according to one of Claims 1-4, in which a short circuit is caused by foreign bodies such as at least partially dissolved particles on an outer conductor contact inner surface.

6. Method for testing an outer conductor contact (2), wherein the method comprises the following steps: a) providing an outer conductor contact (2) at a fixing area (7); b) fixing the outer conductor contact (2) to the fixing area (7); c) inserting a test pin (10) at least partially into the outer conductor contact (2), wherein the test pin (10) is free of voltage; d) applying a voltage to the test pin (10); and e) testing whether a short circuit has occurred between the test pin (10) and at least one electrically conductive foreign body which may be located within the outer conductor contact (2).

7. Method according to Claim 6, in which the method takes place on a line before assembly of the outer conductor contact (2).

8. Method according to Claim 6 or 7, in which the test pin (10) is inserted as far as the stop on an insulator (5) which is arranged within the outer conductor contact (2).

9. Method according to one of Claims 6-8, in which the testing is carried out by an electrical measurement and / or an optical measurement.

10. Method according to one of Claims 6-9, in which the fixing is performed by way of a force-fit and / or form-fit connection with the aid of a fixing apparatus (8).