Device for electromagnetically sealed arrangement of a cable

Abstract

The invention relates to a device for the electromagnetically sealed arrangement of a cable containing an electromagnetic shielding material, with a feedthrough opening (2) in a part (1) for the cable and a contacting means that electrically contacts the shielding material with the part (1) with the feedthrough opening (2), which consists of a coiled spring element (3), with the special feature that the coils of the spring element (3) have a substantially straight retaining section (4) which in the intended mounting position is aligned parallel to the shell of the feedthrough opening (2) and is supported on it, and a spring section which forms a resilient support area (5) to contact the shielding shell of the cable.

Description

The invention relates to a device for the electromagnetically sealed arrangement of a rod-shaped part containing or forming electromagnetic shielding means or of a cable containing a shielding jacket, wherein the device has a part with a passage opening for the rod-shaped part or the cable which is electrically conductive or has at least one inner surface which is electrically conductive in the region of the passage opening, the device has at least one contacting means which is elastically deformable in the radial direction with respect to the central axis of the rod-shaped part or the cable and which electrically contacts the shielding means with the part with the passage opening, and wherein the contacting means consists of a coiled spring element.Devices of this type are known, for example, from U.S. Pat. No. 4,547,623 A, U.S. Pat. No. 5,237,129 A, U.S. Pat. No. 6,354,851 B1, DE 1 646 612 U1, DE 690 23 931 T2, EP 1 673 841 B1 and DE 694 03 174 T2. Whereas DE 1 646 612 U1 discloses an EMC-tight arrangement in the case of a rod-shaped part, namely a cylindrical piston, the other documents cited in the prior art disclose electromagnetic seals of electrical cables which are provided with a shielding jacket. Only DE 694 03 174 T2 has a rod-shaped part which is to be shielded electromagnetically.In the relevant solutions according to the prior art, a coiled spring element in the form of a helical spring is provided as an essential contact element for the electromagnetic shielding. Such helical springs are suitable for use as intended. However, there is a disadvantage in that the arrangement of such a helical spring is only possible with certain dimensions, namely if the rod-shaped part containing or forming the electromagnetic shielding means or the cable with the shielding jacket has a diameter which is relatively closely matched to the part which has the passage opening for the corresponding rod-shaped part or the cable. For example, as can be seen from DE 694 03 174 T2 (compare, for example, FIGS. 5A to 5C of this publication), the spring element, which is designed in the form of an oval helical spring, protrudes only slightly beyond the jacket of the passage opening and / or over the jacket of the rod-shaped part or of the cable, so that different parts with passage openings have to be used for different cable dimensions. This makes the manufacturing diversity and the storage diversity of such parts considerable.The same problem arises in the embodiment described in EP 1 673 841 B1, for which reference is made, for example, to FIG. 8 therein. This also applies to DE 690 23 931 T2, for which reference is made, for example, to FIG. 14 therein. The same problem also arises in U.S. Pat. No. 6,354,851 B1, as a view of FIG. 6 shows. US 2004 / 0070128 A1 discloses inclined coil springs in general and relates in particular to inclined coil springs of different designsIn the solutions known in the prior art, a different embodiment must be provided for each of the different dimensions of cables or rods to be passed through with respect to the part which has the passage opening for the rod-shaped part or the cable. If, for example, cables or rods from a diameter of 5 mm to a diameter of 20 mm are to be guided through such devices in an EMC-tight manner, many dimensions of corresponding parts with passage openings must be produced and completed with the corresponding helical springs.Starting from this prior art, the object of the invention is to provide a device of the generic type which is suitable and intended to make it possible to pass through and contact cables or rods of different dimensions in an EMC-tight manner with one and the same dimension of a part having a through-opening and with one and the same dimension of a coiled spring element serving as contact means.To achieve this object, the invention proposes that the windings of the spring element have a straight holding section which is directed conically at an angle of between 1° and 70° or parallel to the rod-shaped part which is passed through or to the cable and which, in the intended assembly position, is aligned parallel to the casing of the passage opening and is supported on said casing or on the casing of the cable or rod-shaped part, and a spring section which forms a resilient support region, in order to contact the casing of the rod-shaped part or the shielding casing of the cable.The straight holding sections of the spring element form a mounting and contact surface with respect to the casing of the passage opening. The spring sections projecting from these as straight holding sections, which form the support regions for the jacket of the rod-shaped part or the shielding jacket of the cable and contact them, can be matched to the diameter or the radius of the passage opening of the corresponding part, independently of the configuration of the straight holding section, so that they project very far into the passage opening surrounded by the jacket. This embodiment makes it possible, for example, to adapt the dimension of the part with the passage opening to a maximum diameter of a cable or rod-shaped part which can still be guided through this passage opening and fits through this opening with play. The spring element is supported at a wide range of cable dimensions, which range from a largest cable dimension or rod dimension which just still fits through the passage opening, to a smallest dimension which is slightly larger than the channel bounded by the free protruding spring portions which each adjoin the holding portion, in each case as intended both on the inner surface of the passage opening and on the casing of the rod-shaped element or on the shielding casing of the cable which is correspondingly freed of insulation. The length of the spring portion projecting radially inward with respect to the holding portion is in principle arbitrary and only limited by the radius of the passage opening, so that the most varied cable dimensions or rod dimensions can be passed through and contacted in an EMC-tight manner with one and the same device. It is not necessary here to vary the wall or a corresponding recess in the wall of the passage opening depending on the protruding length of the spring portions, because the substantially straight holding portion can easily be mounted in the passage opening or a corresponding recess of the passage opening.Thus, in the case of a relatively slender configuration of the part which has the passage opening, a spring element can be used which has a large supporting length in the actual spring section.Under certain circumstances, it can be provided that the support region is formed by turns of the spring element which are semicircularly connected to the straight holding sections.This results in a spring element which has a cylindrical outer jacket formed by the straight holding sections, and a support region formed by the semicircularly bent spring sections. A disadvantage here is that the protruding support regions can only have a radius which corresponds to half the length of the holding section.In order to be able to make the support region larger, i.e. to be able to grip an even larger plurality of rod-shaped elements or cables with one and the same dimension, it is provided that the support region is formed by straight winding sections which adjoin the straight holding sections at an angle, wherein the spring element has a triangular shape in cross section.In such a configuration, the length of the straight holding section is no longer determining for the protruding length of the spring sections forming the support regions, but the leg length of the support regions is completely independent of the length of the holding section, so that the protruding length of the spring elements can therefore be greater than half the length of the holding section. Thus, with a relatively short length of the holding section, a large protruding length of the spring sections forming the support regions is made possible.In order to facilitate assembly and also to reduce the risk of buckling in the transition regions of the windings into the holding sections, it is provided that the transitions of the windings into the straight holding section are rounded.For the same reason, it is preferably provided that the transitions of the winding sections directed at an angle to one another are rounded.This is also advantageous in particular when the device is used for the passage of cables having a shielding jacket, since the rounded transitions reduce the risk that the support regions of the spring element hook on the shielding of the passed-through cable or damage it.Preferably, it can also be provided that the tip of the triangular shape of the spring element is flattened, so that an approximately trapezoidal shape of the spring element results in cross section.In this case, it can be provided that the wall region of the spring element forming the flattened portion is concavely curved, in particular analogous to a round cross-sectional shape of the rod-shaped part or of the cable.It is also preferably provided that the spring element forms an isosceles triangle in cross section.Instead of such a configuration, an isosceles triangular configuration of the cross section would also be possible, but the isosceles configuration is preferred.In order to be able to cover the largest possible diameter range of rods or cables with one and the same device, it is preferably provided that the spring sections of the spring element extend as far as close to the central axis of the annular spring element.In a manner known per se, it is provided that the windings of the spring element are connected to form an endless annular spring element.A preferred development is seen in the fact that the retaining section of the spring element is fastened to the casing of the passage opening.According to this embodiment, the spring member can be fixed to the part having the through hole, so that a functional unit can be supplied from the manufacturer to the user. A corresponding cable or rod can then be inserted into this device in order to achieve the EMC seal. It would of course also be possible, as is known per se in the prior art, to apply the spring element to the jacket of the rod or of the cable and to keep it under spring prestress, so that the rod or the cable can then be inserted into the element which has the passage opening. By suitable means, the spring element could be locked in the desired position within the passage opening of the corresponding part.Such designs are known per se in the prior art.A possible further development in this regard is seen in the fact that the retaining section of the spring element is fastened to the casing of the passage opening in a materially integral manner, for example, is glued, welded, soldered.A preferred development is seen in the fact that the holding section is held on the casing of the passage opening alternatively or additionally in a positively locking manner.This configuration can be provided as an alternative or in addition to the aforementioned material connection.For a positive connection, it can be provided that the jacket of the passage opening has encircling ribs or an encircling groove, wherein the retaining portions of the spring element are held axially captive between the ribs or the flanks of the groove.It can also be provided that the spring sections of the spring element are directed radially toward the passage channel formed by the passage opening. In the case of such radially directed spring sections, a slight rotational movement is carried out on the cable or rod when the corresponding cable or rod is fed in, so that the radially oriented spring sections tilt in the manner of an iris diaphragm in order to form the corresponding free space for the rod or cable.It can also preferably be provided that the spring sections of the spring element are inclined in the same direction at an angle with respect to the radial direction with respect to the passage opening.Here, a movement of the spring sections is predefined when a rod or cable is introduced, so that the spring sections only move in the direction determined by the predefined angle of inclination.In a manner known per se, it is also provided that the spring element is formed from round wire.In addition, it can be provided that the spring element is formed from stainless steel round wire.It is preferably provided that the part with the passage opening is a threaded nipple of a cable gland, which receives the spring element and has a perforated screw cap and a perforated sealing and / or clamping insert at one end.Such a combination is known, for example, from U.S. Pat. No. 6,354,851 B1, U.S. Pat. No. 5,237,129 A, U.S. Pat. No. 4,547,623 A.It is also particularly preferred that the spring sections, which form the support region, viewed in the radial direction of the annular spring element, have a length which corresponds approximately to the radius of the passage opening.In the case of radial alignment of the spring sections which form the supporting region, the maximum length is determined by the radius of the passage opening, minus the dimension formed by the cross-sectional dimension of the spring wire. If the spring sections are not directed radially but are inclined with respect to the radial direction, a longer configuration of the spring sections is possible, since the spring sections can overlap in the manner of an iris diaphragm.The contact pressure that can be achieved by means of the spring element can be influenced by the material selection of the spring wire and by the wire thickness of the starting material.An exemplary embodiment of the invention is illustrated in the drawing and described in more detail below. It shows: FIG. 1 shows an exploded view of a device according to the invention; FIG. 2 is a detail in plan view; FIG. 3 shows the device in an assembly position as seen in a central longitudinal section III / III of FIG. 4 ; FIG. 4 is a front view of the device.In the drawing, there is shown an apparatus for electromagnetically sealed arrangement of an electromagnetic shielding means containing or forming rod-shaped part or a cable containing a shielding jacket. The device has a part 1 with a passage opening 2 for the rod-shaped part or the cable, which is electrically conductive or at least has an inner surface which is electrically conductive in the region of the passage opening 2. In practice, such a part can consist, for example, of metal or else of doped plastic made electrically conductive by doping. Furthermore, the device has at least one contacting means 3 which is elastically deformable in the radial direction with respect to the central axis of the rod-shaped part or of the cable and which, in the assembly desired state, electrically contacts the shielding means with the part 1 of the passage opening 2, wherein the contacting means 3 consists of a coiled spring element which is electrically conductive, that is to say is formed from metal wire, for example.The invention not only includes the arrangement of a single spring element, but it is also possible to arrange a plurality of spring elements axially one behind the other or to arrange a plurality of spring elements one inside the other, as is known, for example, from DE 690 23 931 T2.In order to achieve that a corresponding device can be used with identical components 1, 2, 3 for rods or cables of considerably different diameters, it is provided that the windings of the spring element 3 have a straight holding section 4 which, in the assembly target position, is aligned parallel to the jacket of the passage opening 2 and is preferably supported on the latter.Alternatively, it can also be provided that the straight holding section 4 is supported on the jacket of the cable to be passed through or of the rod-shaped part.However, this solution is not preferred. Furthermore, the turns of the spring element 3 consist of a spring section which forms a resilient support region 5 in order to contact either the jacket of the rod-shaped part or the shielding jacket of the cable or, in the alternative solution possibility, to contact the jacket of the passage opening 2.In the exemplary embodiment, the support region 5 is formed by straight winding sections which adjoin the straight holding sections 4 at an angle, wherein the spring element 3 has an approximately triangular shape in cross section, as can be seen in particular from the illustration in FIGS. 1 and 3. The transitions 6 of the windings into the straight holder section 4 are rounded. Likewise, the transitions 7 of the winding sections directed at an angle to one another are rounded. In the exemplary embodiment, the straight holding section 4 is directed parallel to the rod-shaped part or cable which has been led through and parallel to the casing of the passage opening 2 of the part 1.As can be seen from the figures, the spring element 3 forms an isosceles triangle in cross section. The spring sections of the spring element 3 forming the support region 5 extend as far as close to the central axis 8 of the annular spring element 3, wherein the windings of the spring element 3 are connected to form an endless, annular spring element.Preferably, the holding section 4 of the spring element 3 is fastened to the casing of the passage opening 2. For this purpose, in the exemplary embodiment, the holding section 4 is held on the jacket in a form-fitting manner. For this purpose, the jacket of the passage opening 2 has a circumferential groove 9, the holding sections 4 being held between the flanks of the groove 9 in an axially non-displaceable manner.The spring sections 5 of the spring element 3 are inclined at an angle in the same direction with respect to the radial alignment with respect to the passage opening 2, as can be seen from the plan view according to FIGS. 2 and 4. This determines a preferred movement of the spring sections 5, which leads to the spring sections being inclined in the same direction, reinforced depending on the diameter of the part passed through, during the insertion of a cable or rod, namely in the same direction which is determined by the predetermined inclination angle.The spring element 3 consists of stainless steel round wire.As illustrated in the figures, the part 1 with the passage opening 2 is a threaded nipple of a cable gland which receives the spring element 3 and has a perforated screw cap 10 and a perforated sealing or clamping insert 11 at one end. This additional arrangement serves to seal and relieve tension on a cable or the like which has been led through by the screw connection cap being screwed onto the part 1 and tightened, the sealing or clamping insert 11 forming the seal and relief of tension with respect to the cable sheath or the like.As can be seen in particular from FIGS. 2 and 4, the spring portions 5, which form the support region 5, viewed in the radial direction of the annular spring element 3, have a length which corresponds approximately to the radius of the passage opening 2. As can be seen from the illustration in FIG. 3, it is possible to insert a rod or a cable into this device and to arrange it in an EMC-tight manner by means of the spring element 3, which has a diameter which corresponds to the central region of the spring element 3 in the view according to FIG. 4, wherein it is also possible to insert cables or rods which are only slightly smaller in diameter than the diameter of the passage opening 2.Thus, for a single size device, a plurality of cables or rods of different diameters must be used.The invention is not limited to the exemplary embodiment, but rather is variable in many ways within the scope of the disclosure.All novel individual and combination features disclosed in the description and / or drawing are considered to be essential to the invention.

Claims

Device for the electromagnetically sealed arrangement of a rod-shaped part containing or forming electromagnetic shielding means or of a cable containing a shielding jacket, wherein the device has a part (1) with a passage opening (2) for the rod-shaped part or the cable, which is electrically conductive or has at least one inner surface electrically conductive in the region of the passage opening (2), the device has at least one contacting means which is elastically deformable in the radial direction with respect to the central axis of the rod-shaped part or of the cable and which electrically contacts the shielding means with the part (1) with the passage opening (2), and wherein the contacting means consists of a coiled spring element (3), characterized in that the windings of the spring element (3) have a straight holding section (4), which is directed conically at an angle of between 1° and 70° or parallel to the rod-shaped part or cable which is led through and which, in the assembly desired position, is aligned parallel to the casing of the feed-through opening (2) and is supported on the latter, and have a spring section which forms a resilient supporting region (5) in order to contact the casing of the rod-shaped part or the shielding casing of the cable.Device according to claim 1, characterised in that the support region (5) is formed by turns of the spring element (3) which adjoin the straight holding sections (4) in a semicircular manner.Device according to claim 1, characterised in that the support region (5) is formed by straight winding sections which adjoin the straight holding sections (4) at an angle, wherein the spring element (3) has a triangular shape in cross-section.Device according to one of Claims 1 to 3, characterized in that the transitions (6) of the windings into the straight holding section (4) are rounded.Device according to claim 3, characterised in that the transitions (7) of the winding sections directed at an angle to one another are rounded.Device according to one of claims 3 or 5, characterised in that the tip of the triangular shape of the spring element (3) is flattened, so that a trapezoidal shape of the spring element (3) results in cross-section.Device according to claim 6, characterised in that the wall region of the spring element (3) forming the flattened portion is concavely curved.Device according to one of Claims 3 to 7, characterized in that the spring element (3) forms an isosceles triangle in cross section.Device according to one of Claims 1 to 8, characterized in that the spring sections of the spring element (3) extend as far as close to the central axis (8) of the annular spring element (3).Device according to one of Claims 1 to 9, characterized in that the windings of the spring element (3) are connected to form an endless annular spring element (3).Device according to one of Claims 1 to 10, characterized in that the retaining section (4) of the spring element (3) is fastened to the casing of the passage opening (2).Device according to claim 11, characterised in that the holding section (4) of the spring element (3) is fastened to the casing of the passage opening (2) in a materially integral manner, for example is glued, welded, soldered.Device according to claim 11 or 12, characterised in that the holding section (4) is held on the casing of the passage opening (2) alternatively or additionally in a form-fitting manner.Device according to claim 13, characterised in that the casing of the passage opening (2) has encircling ribs or an encircling groove (9), wherein the retaining portions (4) of the spring element (3) are held axially captive between the ribs or the flanks of the groove (9).Device according to one of Claims 1 to 14, characterized in that the spring portions (5) of the spring element (3) are directed radially towards the passage channel formed by the passage opening (2).Device according to one of Claims 1 to 14, characterized in that the spring portions (5) of the spring element (3) are inclined at an angle in the same direction with respect to the radial direction with respect to the passage opening (2).Device according to one of Claims 1 to 16, characterized in that the spring element (3) is formed from round wire.Device according to claim 17, characterised in that the spring element (3) is formed from stainless steel round wire.Device according to one of Claims 1 to 18, characterized in that the part (1) with the passage opening (2) is a threaded nipple of a cable screw connection, which receives the spring element (3) and has a perforated screw connection cap (10) and a perforated sealing and / or clamping insert (11) at one end.Device according to one of Claims 1 to 19, characterized in that the spring portions which form the supporting region (5), as seen in the radial direction of the annular spring element (3), have a length which corresponds approximately to the radius of the passage opening (2).Contacting means for use with a device according to one or more of the preceding claims, comprising a coiled spring element (3), characterized in that the windings of the spring element (3) have a straight holding section (4) which is directed conically at an angle of between 1° and 70° or parallel to a rod-shaped part which is led through or to the cable and which, in a desired assembly position, can be aligned parallel to a casing of a feed-through opening (2) and can be supported on the latter, and a spring section which forms a resilient supporting region (5).

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