Patent Grant
9431755
The invention concerns a current-carrying lead, in particular connecting lead and heating tape, for a plug connector, comprising at least two litz wires that are partially surrounded by an electrical insulation. The invention concerns also a plug connector comprising such a current-carrying lead and comprising at least one sealing device provided for the lead that comprises at least one sealing member that comprises at least one elastically deformable sealing part that, by introducing a force that is acting in the longitudinal direction of the lead, is elastically deformable transversely to this longitudinal direction against the lead, wherein the sealing part is deformable elastically by at least one wedge slider that is provided with a conical surface that interacts with a conical surface of the sealing part. The invention also relates to a plug connector in which the lead is supported by a multi-point support in a strain relief device that has four pressure members which are positioned opposite each other in pairs, respectively.
Current-carrying leads in the form of connecting leads and heating tapes are known which are connected to each other by means of the plug connector. By means of the heating tapes, pipes, containers, channels and the like are maintained at defined temperatures. For example, the heating tapes are attached to conveying lines in order to keep the medium flowing within the conveying lines at a defined temperature so that it is flowable or can stream. Often, at the end of the heating tape moisture will deposit and thereby change the leakage current resistance of the heating tape. In particular in moist or wet conditions of use, the moisture penetrates as a result of capillary action or moisture is generated by a pumping effect which is caused by cooling or heating. Between the litz wires of the heating tape, an initially small, over the course of time greater, moisture collection is produced on which electrical leakage currents can flow. Because of this, there is the risk that the heating tape will suffer from scorch marks between the two litz wires. Progressively, the leakage current resistance can even drop so far that short circuiting may be produced.
Moreover, the contacting action of heating tape and connecting lead must be protected from environmental effects in order to avoid short-circuiting by moisture penetration between the potentials of the litz wires.
For this purpose, glands with matched nut are known through which the electrical lead is projecting. The gland is elastically deformed in radial inward direction so that it contacts seal-tightly the heating tape. This deformation of the gland causes flexing, i.e., a deformation in circumferential direction. This has the result that the sealing effect is reduced because due to the flexing movement passageways inwardly into the plug connector are formed. Accordingly, through the gland moisture from the exterior can penetrate and can cause the afore described problems within the plug connector.
The invention has the object to configure the current-carrying lead of the aforementioned kind and the plug connector of the aforementioned kind in such a way that, while providing a simple configuration and inexpensive assembly, it is ensured that a leakage current generation due to moisture in the plug connector is avoided.
This object is solved for the current-carrying lead of the aforementioned kind in accordance with the invention in that the electrical insulation comprises at least one reservoir for an electrically insulating medium that is closed off by at least one plunger that forces the sealing medium through at least one outlet nozzle into at least one sealing space. The invention is solved for the plug connector of the aforementioned kind in accordance with the invention in that the wedge slider is guided in a securing part that axially secures the sealing body and in that the wedge slider is pre-tensioned axially by at least one pressure spring element that is actuatable by at least one pressure member. The invention is further solved in connection with the plug connector comprising a strain relief device in that the first oppositely positioned paired pressure members are positioned angularly to the two other oppositely positioned pressure members and in that two oppositely positioned pressure members are forcibly guided by the two other oppositely positioned pressure members.
The current-carrying lead according to the invention is characterized in that a reservoir containing an electrical insulating medium is integrated in its electrical insulation. It is advantageously an electrically insulating gel with which the collection of moisture on the heating tape end or connecting lead end is avoided. The reservoir is closed off by a plunger so that the sealing medium cannot escape to the exterior. When the plunger is pushed into the reservoir, the sealing medium contained therein is forced through the outlet nozzle into the sealing space. Here, the sealing medium distributes within the critical space and prevents thus that moisture can collect therein between the litz wires. The volume of the reservoir is matched to the volume of the sealing space in such a way that the sealing medium completely fills the sealing space in any case. The sealing space is located in front of the insulated end of the heating tape or the connecting lead. The litz wires extend through the sealing space and are, by the way, surrounded by the electrical insulation.
The electrical insulation is advantageously an insulation body that surrounds insulatingly and with mechanical protecting action the litz wires, from which insulation has been stripped across a portion of their length, and that is attached to the heating tape or to the connecting lead.
Advantageously, the plunger is secured against displacement in at least one position on the insulation. The plunger is secured at least in the pushed-in position so that it is ensured that the sealing medium cannot flow out of the sealing space into the reservoir.
It is however also possible that the plunger is positionally secured in its initial position when the reservoir is filled. Then it is ensured that the plunger secures the reservoir outwardly and cannot be lost.
Advantageously, the plunger is displaced only when plugging in the plug connector so that only then the sealing medium is displaced from the reservoir into the sealing space.
The plug connector according to the invention comprises the sealing device which reliably protects the contacting action of heating tape and connecting lead from environmental effects. The sealing device comprises the sealing body which comprises the elastically deformable sealing part. By introducing a force acting in longitudinal direction of the lead, it is elastically deformed transversely to this longitudinal direction so that it is contacting seal-tightly the outer side of the lead. Due to this elastic deformation, no flexing action occurs so that no passageways for moisture and the like can form. The sealing part is elastically deformed by at least one wedge slider. With it, the force that is acting in the longitudinal direction of the lead can be deflected very easily into the force which is transversely oriented thereto in order to apply seal-tightly the sealing part against the electrical lead. The sealing part is provided with a conical surface which interacts with a conical surface of the wedge slider. In order to deform the sealing part reliably by means of the wedge slider, the wedge slider is guided within a securing part. By means of the securing part, the sealing body is axially secured so that the latter remains in its position when its sealing part is elastically deformed. The wedge slider is axially pretensioned by means of the at least one pressure spring element so that the sealing function is ensured across a great temperature range. Since at corresponding temperatures the material property and the dimensions of the parts will change, the pre-tensioned wedge slider ensures that the sealing part is always seal-tightly resting on the electrical lead. The pressure spring element is actuated by the at least one pressure member. The pressure spring element is thus supported on the wedge slider as well as on the pressure member that effects the pretension acting on the wedge slider.
The sealing body is advantageously secured in the connector member of the plug connector against transverse sliding. In this way, by means of the transverse sliding securing action and the securing part, the sealing body is properly positionally secured upon elastic deformation of the sealing part as well as in the mounted position.
The pressure member is advantageously slidably guided within the securing part.
The pressure member is advantageously arranged such that it is actuated upon insertion of a plug component group.
The actuating element is advantageously a component of such a plug component group of the plug connector.
In the plug connector, advantageously a strain relief device for the lead is provided downstream of the sealing device.
In an advantageous embodiment, the securing part comprises an annular wall that is resting against an inner wall of a receiving space of a connector member of the plug connector.
In a preferred embodiment, the wedge member of the wedge slider is arranged between the securing part and the sealing part. In this way, the sealing part is forced securely against the lead to be sealed.
Preferably, the wedge member of the wedge slider has a straight outer side in axial section with which the wedge member is resting against an appropriate inner surface of the securing part. In this way, it is prevented that the securing part is deformed in radial direction inwardly.
The pressure spring element engages advantageously an end face recess of the wedge slider.
The plug connector according to the invention comprises at least one strain relief device by means of which a multi-point support action of the lead is enabled. The strain relief device is arranged such in the plug connector that possibly occurring tension forces are kept away from the contacting action and the downstream sealing device. The multi-point centering action has the result that the electrical lead, which can be a heating tape or a connecting lead, is centered. When downstream of the strain relief device a sealing device for the strain-relieved electrical lead is provided, then an optimal sealing action is ensured as a result of the centering action. The pressure members of the strain relief device are arranged in pairs opposite each other wherein the first oppositely positioned paired pressure members are positioned angularly to the two other oppositely positioned pressure members. Two oppositely positioned pressure members are forcibly guided by the two other oppositely positioned pressure members. In this way, by the movement of two oppositely positioned pressure members, all pressure members are moved in the direction toward or away from the electrical lead. In this way, it is possible to clamp the electrical lead very simply between the pressure members for strain relief or to release the electrical lead again. Due to the forced guiding action, an automatic centering action of the lead is realized so that the lead can be optimally sealed.
An advantageous forced guiding action results when the forcibly guided pressure members engage, by means of cams, guides of the other two oppositely positioned pressure members. With such a form fit action between the pressure members a reliable uniform adjustment of all pressure members is achieved.
In an advantageous embodiment, the guides of the other pressure members are provided at lateral surfaces of these pressure members and extend oppositely slanted relative to each other. In this way, it is ensured in a simple way that the pressure members are moved opposite to each other outwardly or inwardly in the direction toward the lead.
In order for the lead to be arranged reliably between the pressure members, it is advantageous to provide two pressure springs between two oppositely positioned pressure members. They load these two pressure members in such a way that they move away from the lead. By means of the forced guiding action, the two other pressure members are also moved correspondingly. By means of the pressure springs, the pressure members are thus moved apart from each other.
The pressure springs are seated advantageously on link members which link the two oppositely positioned pressure members with each other.
In an advantageous embodiment, the oppositely positioned pressure members are perpendicularly slidable relative to the other two oppositely positioned pressure members.
Further features of the invention result from the further claims, the description, and the drawings.
The invention will be explained in more detail with the aid of some embodiments illustrated in the drawings. It is shown in:
The plug connector serves to electrically connect a connecting lead with a heating lead. The released heat of the heating lead keeps pipes or surfaces at the constant desired temperature and compensates partially differences in the ambient temperature.
The plug connector has two connector members 1, 2 which are shown in
The connector member 2 is provided with the heating tape 5 that, like the connecting lead 3, is extending out of the connector member. The heating tape 5 is electrically connected with male connectors 6 which engage the female connectors 4 when the connector members 1, 2 are plugged in (
The female connectors 4 of the connector member 1 project partially into a receiving space 7 which is delimited by a part of the housing 8 of the connector member 1. The connector member 2 engages with a head part 9 the receiving space 7. The head part 9 is form-fittingly secured in the receiving space 7 and is resting with its outer wall 10 against the inner wall 11 of the receiving space 7.
The head part 9 is provided on its exterior side with a circumferential seal 12 which is accommodated in an annular groove 13 that is open toward the end face of the head part 9. The seal 12 covers also a part of the end face 14 of the head part 9. In the plugged-in state, the seal 12 is seal-tightly resting against the inner wall 11 of the receiving space 7.
The connector member 2 is comprised of three component groups 15 to 17 (
Into the component group 17, the component group 16 is inserted which is arranged with form fit in the receiving space 18. The component group 16 is inserted so far that with its end face 20 it contacts the bottom 19 of the component group 17 (
The component group 16 is provided with a shaped seal 22 with which the heating tape 5 is sealed. Also, with the shaped seal 22 the component group 16 is sealed near the bottom 19 relative to the component group 17.
The component group 16 is completely accommodated within the receiving space 18. In a final mounting step, the component group 15 provided with the male connectors 6 is inserted into the receiving space 18. The component group 15 has a cover 23 with which, in the mounted position (
The head part 9 of the component group 17 is provided at the end face with at least one locking element 31 with which the component group 15 is locked in the mounted position. The cover 23 of the component group 15 is provided with at least one counter locking element (not illustrated) that is interacting with the locking element 31. The male connectors 6 are projecting through the cover 23 of the component group 15.
The component groups 15, 16 each are formed as plug-in component groups which can be mounted by simple plug-in processes in the component group 17.
The connector member 1 (
The component group 33 is substantially of the same configuration as the component group 15. The component group 33 comprises a cover 38 that projects past a housing part 39 on all sides and, in the mounted position (
Through an opening 45 in the bottom 37 of the housing 34 of the component group 32, the connecting lead 3 is projecting whose leads are electrically connected with the female connectors 4. By means of the sealing device 36, the connecting lead 3 is reliably sealed within the receiving space 35.
In the bottom part of the housing 34, a strain relief device 44 is accommodated as will be explained in more detail with the aid of
At one end of the heating tape 5 (
In the area between the insulating parts 51, 52, the insulating element 47 is provided with a reservoir 53 for an electrically insulating sealing medium 54. The sealing medium is advantageously an electrically insulating gel.
The reservoir 53 is closed off by a plunger 55. The reservoir 53 is located in a center part 56 of the insulating element 47. Advantageously, the center part 56 is in the area between the insulating parts 51, 52 and is advantageously monolithically formed therewith. The plunger 55 closes off the reservoir 53 at the free end of the center part 56. At the other end, a nozzle-shaped opening 57 with only minimal cross-section opens into the reservoir 53 and penetrates the bottom of the center part 56.
The center part 56 of the electrical insulation element 47 is spaced from the heating tape 5 so that between them a sealing space 58 is formed which is empty before connecting the heating tape 5 to the male connectors 6. The sealing space 58 is penetrated by the litz wires 49, 50. In their area, the sealing space 58 is provided with conical sealing spaces 59, 60 through which the litz wires 49, 50 are extending.
When the heating tape 5 is connected to the male connectors 6, the plunger 55 with its head 61 will contact the bottom 62 of the housing part 24 of the component group 15. Upon assembly, the plunger 55 is pushed into the reservoir 53 to such an extent that, with the heating tape 5 mounted, it is resting with its head 61 on the end face 63 of the center part 56. The dimensions are such that the head 61 is resting on the bottom 62 of the housing part 24 as well as on the end face 63 of the center part 56 (
The plunger 55 is resting against the wall of the center part 56 in such a way that no sealing medium 54 can escape past the plunger 55.
In the initial position according to
The plunger 55 has at least one further annular groove 65 in the area of the underside of the head 61. Into it, the rim 64 of the center part 56 engages when the litz wires 49, 50 are connected to the male connectors 6.
In the embodiment, the plunger 55 is also provided with a further annular groove 65 so that it can be maintained in an intermediate position.
In the end position according to
This sealing action cannot only be used in case of the heating tape 5 but also for the connecting lead 3.
The sealing device 36 in the connector member 2 has a sealing body 66 (
An annular part 70 adjoins the radial outer rim of the annular disk 69 and an annular part 71 adjoins the radial inner rim of the annular disk 69. Both annular parts 70, 71 are formed monolithically with the annular disk 69. The outer annular part 70 is provided at its outer side with a corrugated profile 72. With it, it is resting seal-tightly against the inner wall 27 of the receiving space 18.
The inner annular part 71 which is longer in axial direction of the sealing body 66 is also provided on the inner side with a corresponding corrugation profile 73. It extends from the free end only across a part of the axial height of the annular part 71. Adjoining the annular disk 69, the inner annular part 71 is resting with its inner side against an annular wall 74 which is projecting from the bottom 19 into the receiving space 18 and delimits an insertion opening 75 for the heating tape 5.
The inner annular part 71 of the sealing body 66 has a slanted end face 76 interacting with a wedge slider 77. It is axially slidably supported within a securing part 78.
The securing part 78 has an annular wall 79 which is resting against the inner wall 27 of the receiving space 18. The wedge slider 77 is resting with its exterior side of the wall 80 against the inner side of the wall 79. The wall 80 adjoins the wedge member 81 which is of an annular shape and whose end face wedge surface 82 is interacting with the conical end face wedge surface 76 of the sealing body 66. The wedge member 81 has a smaller outer diameter than the wall 80.
The annular wall 80 of the wedge slider 77 has two depressions 83 in which a pressure spring 84 is positioned, respectively. The pressure springs 84 are supported with one end on the bottom of the depressions 83 and with the other end on a pressure member 85 that is slidably guided within the securing part 78. The pressure member 85 is resting on an actuating element 86 that is guided also on the inner side of the wall 79 of the securing part 78. The actuating element 86 is a component of the component group 15 that is inserted into the component group. During this insertion process, the pressure member 85 is displaced by the actuating element 86.
The pressure springs 84 are pretensioned such that the sealing body 66 ensures the sealing action of the heating tape 5 even after long periods of use. The sealing body 66 and the sealing wedge 77 are matched to each other such that over an extended period of use of the plug connector a sufficiently large retensioning travel is available. In this way, it is ensured that the annular part 71 of the sealing body 66 is seal-tightly resting about the circumference of the heating tape 5.
The wedge slider 77 is properly guided within the securing part 78. The securing part 78 has a terminal area 87 with which it engages between the two annular parts 70, 71 of the sealing body 66. The terminal area 87 is designed such that the two annular parts 70, 71 with their outer sides facing each other are resting areally against the outer sides of the terminal area 87 and the annular disk 69 of the sealing body 66 in the initial position (
With the sealing body 66 and the wedge slider 77 a targeted elastic deformation is achieved. The spring forces may be minimal. They are only adjusted to be so high that the annular part 71 of the sealing body 66 is resting in radial inward direction seal-tightly on the heating tape 5. The spring force can be relatively minimal because the radial deformation is achieved by the wedge surface 82 of the wedge slider 77. As a result of the radial deformation by means of the described wedge effect, the inner annular part 71 is substantially moved only radially against the heating tape 5 so that at the contact locations between the annular part 71 and the heating tape 5 no flexing effect occurs. Such flexing actions occur in known seals because they deform in circumferential direction whereby leakages occur so that the medium can reach the litz wires of the heating tape 5.
In the initial position of
The corrugation profiles 72, 73 on the two annular parts 70, 71 are designed in axial section approximately of a semi-circular shape. The two corrugation profiles have thus an O-ring-like contour which ensures a proper sealing action. In the inserted position, this O-ring-like contour is moreover elastically deformed so that a high sealing action is achieved.
Since the sealing body 66 is pretensioned by the pressure springs 84, the plug connector can be used also in a wide temperature range without problems without the sealing action being impaired. Thus, the described plug connector is for example suitable for a temperature range of approximately −60° C. to approximately +180° C. Since in this temperature range the material properties as well as the dimensions of the individual parts of the component group will change, by means of the described elastic deformation of the sealing body 66 in combination with the pretensioned pressure springs 84 it is ensured that a good sealing action is ensured any time.
In the installed position (
In the embodiment according to
In the embodiment according to
With the two described embodiments of sealing devices 36, heating tapes 5 with different outer dimensions can be sealed. With the sealing device 36 not only the heating tape 5 is sealed but also the area of the downstream terminals 90 (
With the aid of
The strain relief device 44 is provided on both connector members 1, 2 for the connecting lead 3 as well as the heating tape 5 (
The connecting lead 3 or the heating tape 5 is clamped between four pressure members 91 to 94. In this way, a four-point strain relief action is provided. The pressure members 91 and 92 are approximately of the same configuration and arranged mirror-symmetrical to each other. The oppositely positioned pressure members 93 and 94 are embodied identically but are mirror-symmetrically arranged relative to each other. For this reason, in the following only one of the pressure members 91 and 93 will be explained in more detail.
The pressure member 91 has a block-shaped base member 95 with two lateral surfaces 96, 97 that are parallel to each other. The underside 98 extends substantially straight while the opposite top side 99 is convexly curved across its length. The base member 95 has at both ends narrow sides 100, 101 that are parallel to each other and adjoin at a right angle the lateral surfaces 96, 97.
The two lateral surfaces 96, 97 are provided with recesses 102, 103 of which in
The base member 95 is penetrated by two openings 106, 107 that are parallel to each other as well as perpendicular to the underside 98. Through these openings 106, 107, screws 108, 109 are inserted with which in connection with the threaded bushings 110, 111 the two pressure members 91 and 92 are linked with each other. Since the pressure members 93, 94 are connected with form fit with the pressure members 91, 92, the pressure members 93, 94 are also secured by means of the screws 108, 109 and the threaded bushings 110, 111.
At half the length, on the lateral surfaces 96, 97, a rib 112, 113 is provided, respectively, which extends in the vertical direction from the bottom side 98 to the top side 99 of the base member 95 and separates the two grooves 104, 105 from each other. The ribs 112, 113 project past the lateral surfaces 96, 97.
At half the length, the bottom side 98 of the base member 95 is provided with a recess 114 which is matched to the contour of the connecting lead 3 or of the heating tape 5. On either side of the recess 114, two projections 115, 116 extend past the bottom side 98. The projections 115, 116 extend across the width of the underside 98 and serve as stops with which the pressure members 91, 92 may come to rest on each other. The projections 115, 116 are so high that in contact position the connecting lead 3 or the heating tape 5 positioned therebetween is not deformed in an impermissibly strong way.
The pressure members 93, 94 are designed as sliding wedges that are slidable perpendicular to the pressure members 91, 92. The pressure members 93, 94 comprise a flat clamping piece 117 whose end face clamping surface 118 (
From the top side and bottom side of the clamping piece 117, two flat webs 119, 120 are projecting along its longitudinal side that each are of a triangular configuration. The triangle sides that are facing the connecting lead 3 or the heating tape 5 of all webs 119, 120 are positioned in a common plane. Near the top triangle tip the webs 119, 120 are provided with cams 121, 122 on their inner sides that are facing each other. The cams 121, 122 engage the grooves 104, 105 of the pressure members 91, 92.
In the area between the pressure members 91, 92, a pressure spring 123, 124 is seated, respectively, on the screws 108, 109 and is supported with its ends on oppositely positioned bottom sides 98 of the pressure members 91, 92. In the mounted position of the strain relief device 44, the pressure springs 123, 124 are pretensioned.
The screws 108, 109 are positioned recessed with their screw head 125, 126 in the openings 106, 107 of the pressure member 91 (
The threaded bushings 110, 111 are positioned recessed in the openings 106, 107 of the base member 95. These openings are matched to the shape of the threaded bushings 110, 111 such that the latter are resting areally across their length against the inner wall of the openings 106, 107.
The screws 108, 109 are screwed in initially only so far into the threaded bushings 110, 111 that the pressure members 91 to 94 have a spacing relative to the connecting lead 3 or to the heating tape 5 (
The pressure springs 123, 124 ensure that the pressure members 91 to 94 are automatically returned upon unscrewing the screws 108, 109. The pressure members 93, 94 are moved away from each other as a result of their mandatory guiding action in the pressure members 91, 92.
The triangular webs 119, 120 of the pressure members 93, 94 are positioned in the recesses 102, 103 of the pressure members 91, 92. The webs 119, 120 are so narrow that they do not project, or only project a little, from the recesses 102, 103. The strain relief device 44 therefore occupies only little space.
As shown in
With the 4-point clamping action, the connecting line 3 or the heating tape 5 is always centrally clamped. Accordingly, the connecting lead 3 or the heating tape 5 are also guided centrally through the inlet opening of the connector members 1, 2 into the interior. Since a 4-point clamping action is realized, the connecting lead 3 or the heating tape 5 are not changed, or changed only a little, with regard to their circumferential shape contour. The four points of attack of the pressure forces lead to a reliable and high strain relief action so that even at higher tension forces there is no risk that the connecting lead 3 or the heating tape 5 is pulled out of the connector members 1, 2.
The strain relief device 44 ensures also that the heating tape and the connecting lead are centered exactly relative to the sealing device and therefore also a proper sealing action is ensured.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2011 121 938 | Dec 2011 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2012/005233 | 12/18/2012 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2013/091838 | 6/27/2013 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4717355 | Mattis | Jan 1988 | A |
| 5358429 | Mina | Oct 1994 | A |
| 6390847 | Katwala | May 2002 | B2 |
| 7338306 | Chen | Mar 2008 | B1 |
| 20070066134 | Burris et al. | Mar 2007 | A1 |
| 20100112855 | Paynter et al. | May 2010 | A1 |
| Number | Date | Country |
|---|---|---|
| 87 07 994 | Jul 1987 | DE |
| 2 908 238 | May 2008 | FR |
| 2 167 614 | May 1986 | GB |
| Entry |
|---|
| FR2908238. Philippe, Electrical Connector with Insulation Gel, 2008. Translation of Description. |
| Number | Date | Country | |
|---|---|---|---|
| 20150044902 A1 | Feb 2015 | US |
