Patent Document

CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 20 2009 011 857.6 filed Sep. 2, 2009, the entire contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention pertains to a high-temperature patch plug for connection lines, as it is used especially for connecting electric supply and/or signal lines to heating elements and/or thermocouples or temperature sensors. 
     BACKGROUND OF THE INVENTION 
     A plurality of patch plugs, in which electric connection lines are connected to an insulating, one-piece housing with a contact element accommodated in said housing, are already known. The housings are manufactured, as a rule, from a plastic, injection molding processes being used in many cases. 
     However, such patch plugs do not, as a rule, meet the special requirements that are associated with high-temperature applications, in which the plugs are exposed to a thermal load of 120° C. and higher. Only a few of the electrically insulating materials that can be used for insulating patch plug housings are sufficiently resistant to such a thermal load. However, the possibility of making it possible to manufacture a housing with a desired design especially according to the injection molding process by adapting the material use is thus eliminated as well. This problem becomes even more acute as the desired designs become ever more compact. 
     Usual high-temperature patch plugs are designed for this reason, as a rule, such that a connection is established in them for every individual pole between a contact element and a conductor and the corresponding connection is then surrounded, especially after the plug thus prepared has been combined with a counterplug, with a housing made of PEEK or a heat-shrinkable sleeve, which said housing is coordinated with the conductor cross section and the external diameter of the individual conductor and is crimped with same and is thus thermally and electrically insulated. Such high-temperature plugs are available, e.g., from Electrolux under the name “high-temperature plug-in connection HTC.” 
     The drawback of this embodiment is that the manufacture of a plug-in connection is associated with a relatively great effort. Furthermore, the space requirement is relatively high, especially for multipole high-temperature plug-in connections, which are based in these plugs. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is therefore to make available a high-temperature patch plug for connection lines, especially for connecting heating elements and/or thermocouples, as well as temperature sensors, which is compact and can be manufactured in a favorable manner. 
     The high-temperature patch plug according to the present invention for connection lines, especially for connecting electric supply and/or signal lines to heating elements and/or thermocouples or temperature sensors, has one pole or a plurality of poles. The poles comprise each a contact element connected to an inner conductor of a connection line. 
     The high-temperature patch plug has, furthermore, a one-piece, insulating housing, which encloses an interior, in which at least the at least one contact element is partially accommodated. On the side facing away from the plugging side, the housing has at least one insertion opening for inserting the pole and, on the side facing the plugging side, a passage opening for each pole. The passage openings are in connection with the insertion opening via the interior of the housing. They are used especially to pass through pins of a male contact element of the high-temperature patch plug or of the corresponding counterplug, but it is, in principle, also possible to pass female connection parts of the contact element through them. The contact element is locked into the housing for each pole at a locking step arranged in the interior of the housing such that a motion of the contact element against the plugging direction is limited by the locking. The locking step is formed here by an irreversible deformation of the housing; at the site at which the locking step is arranged, the outer wall of the housing is pressed in in the direction of the interior of the housing in the finished high-temperature patch plug even without the action of external forces. A housing with a locking step embodied in this manner can be manufactured in an especially simple and favorable manner. 
     Especially preferred is an embodiment of the present invention in which the locking step belonging to a particular pole is designed such that relative to a parallel to the plugging direction, which passes through the center of the passage opening for said pole, the distance between a surface of the particular locking step, which said surface faces said parallel, and said parallel is greater than the shortest distance between a point of a wall of the respective passage opening and said parallel. As an alternative, this feature can be embodied by the respective locking step being lower than the highest point of the wall of the corresponding passage opening, which extends in the same direction as the locking step. 
     An advantageous consequence of this geometric embodiment of the housing is that a contact element, which is pushed in through the insertion opening and whose motion against the plugging direction is limited by the locking step after the locking, is also limited by the wall of the passage opening in terms of a motion in the plugging direction. It thus becomes possible to ensure the fixation of the contact element in the housing by a single locking alone, which leads to a simple and compact design. 
     Provisions are made in an advantageous embodiment of the present invention for the contact element or contact elements to be locked at a surface of the locking step, the surface being at an end surface of a duct, which extends from the locking step in the plug-side direction to the plug-side housing wall and is open in the direction of the interior. Separation of the locked parts is possible in this geometric embodiment. This can be brought about in an especially simple manner if the duct or ducts has/have a duct opening, which passes through the plug-side wall of the housing. This makes it possible to insert a tool to release the locking connection in a simple manner. 
     A high-temperature-resistant plastic with a long-term temperature stability of &gt;200° C., especially FEK (polyether ketones), PFA (perfluoroalkoxoethylene), FEP (perfluoroethylenepropylene) or VESPEL (a polyimide), is an especially suitable material for the housing because of its good thermal deformability. 
     To avoid a possible electric interaction between the poles, it is advantageous, if the high-temperature patch plug has more than one pole, if the interior of the housing has partitions, which separate the contact elements of the respective poles from one another. In particular, each pole may be accommodated in a separate chamber each of the interior, which connects a corresponding insertion opening and the corresponding passage opening with one another. 
     To secure a plug-in connection established by means of the high-temperature patch plug, it is advantageous to arrange at least one burr, at least one detent or at least one depression on at least one surface of the housing to lock the housing with a counterplug. This may happen, for example, according to a locking principle or according to the principle of a bayonet catch. 
     A material for the contact elements, which is especially suitable for high-temperature application, is steel, especially spring steel. The locking of the contact elements is brought about preferably with a stop spring provided on these. If the contact elements are designed as clamping bushings, it is possible to generate high contact pressures, which are especially important in case of high-temperature applications, between the bushing and the corresponding male contact element of the counterplug, which contact element is inserted into the bushing through the corresponding passage openings. Furthermore, it is ensured, if the contact element of the high-temperature patch plug for connection lines is designed as a bushing, that any voltages that may still be present on the connection lines are present only within the insulating housing, whereas open contacts, which are live, may be present in case of an embodiment as a contact pin projecting from the housing, which is, of course, in principle, possible. 
     The high-temperature patch plug can be manufactured in an especially simple manner if the irreversible deformation of the housing to form the locking step is carried out by thermal and/or mechanical deformation during the manufacture. 
     An especially tight embodiment, which can effectively prevent, e.g., the penetration of moisture, is obtained if the insertion opening or, in case of a plurality of poles, the insertion openings of the housing are sealed with a cement, a molding made of silicone or plastic or a pourable sealing compound. This effect can be extended to a plug-in connection with a counterplug extending fully or partially over the high-temperature patch plug if the high-temperature patch plug or the housing thereof is surrounded with a sealing element. This may be concretely an O-ring, which is inserted into a groove extending at right angles to the plugging direction through the housing. 
     The present invention will be explained in more detail on the basis of drawings. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1   a  is a view of a single-pole exemplary embodiment of the high-temperature patch plug showing the plugging side viewed in the plugging direction; 
         FIG. 1   b  is the view of a two-pole exemplary embodiment of the high-temperature patch plug showing the plugging side viewed in the plugging direction; 
         FIG. 1   c  is the view of a four-pole exemplary embodiment of the high-temperature patch plug showing the plugging side viewed in the plugging direction; 
         FIG. 2  is a sectional view of the exemplary embodiment from  FIG. 1   a , cut along line B-B; 
         FIG. 3  is another sectional view of the exemplary embodiment from  FIG. 1   a , cut along line C-C; 
         FIG. 4   a  is the view of a plug-in connection manufactured with the use of the high-temperature patch plug shown in  FIGS. 1   a ,  2  and  3  with a counterplug, viewed at right angles to the plugging direction, and 
         FIG. 4   b  is the plug-in connection from  FIG. 4   a , cut along line A-A. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings in particular, identical reference numbers are used for identical components of the same exemplary embodiments in all figures, unless mentioned otherwise. 
       FIG. 1   a  shows the view of a single-pole exemplary embodiment of a high-temperature patch plug  50 , viewed against the plugging direction. A housing  51  with a detent  52  is recognized. The plug-side boundary surface of housing  51  is passed through by a passage opening  57 , which is limited by a double circle because of a wall  67  beveled as an insertion aid, and by a duct opening  65 . Lines B-B and C-C represent section lines, which illustrate the perspective of the views in  FIGS. 2 and 3 , from which the design of the high-temperature patch plug  50  appears even more clearly. 
       FIG. 1   b  shows the same view of a two-pole high-temperature patch plug. A housing  81  with a detent  82  is recognized. The plug-side boundary surface of housing  81  is passed through in this embodiment by two passage openings  83  and by two duct openings  84 . The passage openings  84  are arranged next to each other and each above the corresponding duct openings  84 . The arrangements of the passage openings  83  and duct openings  84  are, in principle, freely selectable as desired, but it is advantageous to arrange the duct openings  84  between a wall of housing  81  and the passage openings  83  associated with the respective duct openings, because this contributes to a more compact design. 
       FIG. 1   c  shows the same view of a four-pole high-temperature patch plug. A housing  91  with a detent  92  is recognized. The plug-side boundary surface of housing  91  is passed through in this embodiment by four passage openings  93  and by four duct openings  94 . The passage openings  93  are arranged each next to each other, and the corresponding duct openings  94  are arranged each between the passage openings  93  and a wall of housing  91 . 
       FIG. 2  shows a sectional view of the exemplary embodiment from  FIG. 1   a , cut along line B-B. 
     The high-temperature patch plug  50  has a housing  51  made in one piece, which preferably consists of a ceramic or a high-temperature-resistant plastic. Housing  51  has, furthermore, a detent  52 , which can be locked, as is shown in  FIG. 4   b , with a recess  22  in a tongue  21  of a second sleeve  20  of a counterplug  10  in order to prevent unintended separation of the plug-in connection. 
     Housing  51  has, furthermore, on the plugging side, a passage opening  57  with a wall  67  beveled as an insertion aid and a duct opening  65  and, on the side located opposite the plugging side, an insertion opening  63 . Passage opening  57  and insertion opening  63  are connected to one another via an interior  59  of housing  51 . The duct opening  65  is likewise connected to the interior  59  via a duct  56 , which extends in parallel to the plugging direction and is open towards the interior  59 . A deformation of the housing  51  forms a locking step  53 , whose plugging side forms the end surface of duct  56 , which said end surface faces away from the plugging side. A contact element  64 , which can be pushed in through the insertion opening  63  and is designed here as a clamping bushing with clamping legs  54 ,  58  and with a mounting area  62  and preferably consists of steel, especially spring steel, is inserted into the interior  59 . As is apparent from  FIG. 3 , contact element  64  has two more clamping legs  68 ,  69 , which cannot be recognized in the view shown in  FIG. 2 . A stop spring  55 , which is locked with locking step  53 , is arranged at clamping leg  58 . 
     An advantageous embodiment of the present invention can be illustrated once again on the basis of the view shown in  FIG. 2 : This figure shows a straight line P, which extends in parallel to the plugging direction through the center of passage opening  57 . The surface  66  of the locking step  53  facing the straight line P is at a greater distance in this exemplary embodiment from this straight line than the distance between a point of wall  67  of the passage opening  57  and the parallel P. The locking step  53  is thus lower than the part of the wall  67  of the passage opening  57 , which part is oriented in the same direction. 
     It is achieved due to this geometric relationship that even though contact element  64  can be pushed in the plugging direction over the locking step  53  until it becomes locked, it cannot be pushed out of the housing  51 . In particular, nearly clearance-free seating of the locked contact element  64  can be achieved in case of corresponding adaptation of the length ratios between housing  51  and the length of the clamping legs  54 ,  58  and the arrangement of the position of stop spring  55  at the clamping leg  58 . 
     The embodiment of housing  51  shown with plug-side duct opening  65  and duct  56  can be manufactured in a simple, cost-effective and novel manner with the use of injection molding techniques. The housing  51  is manufactured at first and the housing is then deformed, with the contact element  64  inserted and already connected to an inner conductor  61  of a connection line  60 , at a point at which the locking step  53  is to be prepared. A preferred possibility for this is, for example, a local thermal deformation. To obtain a secure and reliable high-temperature patch plug  50 , it is desirable to avoid breaking through the housing  51  at right angles to the plugging direction; the use of a punch working in this direction is therefore ruled out during the manufacture for preparing the locking step  53 . 
     As is shown in  FIG. 4   b , a contact element  12  of the counterplug  10 , which said contact element is designed as a contact pin, can be clamped between the clamping legs  54 ,  58  and the other two clamping legs  68 ,  69 , which cannot be recognized in this sectional view. A reliable electrical and mechanical contact is ensured between the respective contact elements  12 ,  64  due to the high pressure of the clamping legs, which is made possible by the use of steel as the material for the contact elements even at high temperatures. 
     An electric contact with an exposed inner conductor  61  of a connection line  60 , which is inserted over a certain section into the housing  51  through the insertion opening  63 , is made in the receiving area  62  of the contact element  64 . 
     A preferred embodiment of a multipole high-temperature patch plug is obtained, in principle, by arranging the desired number of single-pole patch plugs, which is achieved such that detents  52  of the single-pole patch plugs always point in the direction of an outer wall of the resulting plug housing  51 . 
     The inner walls between the individual single-pole assembly units or cells of the resulting multipole high-temperature patch plug are now made preferably thinner. 
       FIG. 3  shows another sectional view of the exemplary embodiment from  FIG. 1   a , cut along line C-C. The design, which appears from  FIG. 3 , fully corresponds to the design described in detail on the basis of  FIG. 2 ; reference is explicitly made to the description of  FIG. 2  to avoid repetitions and only the further recognizable details will be dealt with. Metal strips  70 ,  71 , which are arranged in the connection area  62  of contact element  64  and are pressed onto the inner conductor  61  to fix same, can be recognized especially clearly in this section. Furthermore, the two clamping legs  68 ,  69 , which are not visible in  FIG. 2 , can be recognized in this section. It also becomes clear that stop spring  55  is formed by a material strip of the clamping leg  58  here. 
       FIG. 4   a  shows the view of a novel plug-in connection manufactured with the use of the high-temperature patch plug shown in  FIGS. 1 through 3  with a counterplug  10 , viewed at right angles to the plugging direction. Only the metal jacket  16  of the metal-jacketed connection line  19 , the connection sleeve  11  and the second sleeve  20  with tongue  21  and recess  22  are recognized from the counterplug  10  in this view. A connection line  60 , a part of a housing  51 , over which part of the second sleeve  20  does not extend, and a detent  52 , which is arranged at housing  51  and meshes with the recess  22 , can be recognized from the high-temperature patch plug  50 . Details of the design can be found from the sectional view along line A-A, which is shown as  FIG. 4   b.    
     The view of the high-temperature patch plug  50 , which is shown in  FIG. 4   b , is exactly identical to the view shown in  FIG. 2 . Reference is therefore made for its design to the description of  FIG. 2 . 
     Concerning the design of the counterplug  10 ,  FIG. 4   b  shows a metal-jacketed connection line  19 , comprising a wire section  18 , which is surrounded at right angles to its first direction of extension by an insulating embedding  17  and a metal jacket  16 . A wire end  14  projects in the plugging direction from the front surface of the metal-jacketed connection line  19 . 
     The end section of the metal-jacketed connection line  19  is surrounded at right angles to the first direction of extension of the metal-jacketed connection line  19  by a connection sleeve  11  made of metal, which is firmly connected to the metal jacket  16 . Connection sleeve  11  extends in the plugging direction beyond the end of the metal jacketed connection line  19 . 
     Wire end  14  is in contact in a contact area  15  with a contact element  12 , which is designed here as a contact pin with a hole, which is, however, not visible in  FIG. 2  because it is filled by the plug-side end section of the wire end  14 . Contact element  12  projects over the connection sleeve  11  in the plug-side direction. The space area between contact element  12  or the wire end  14  and the part of the connection sleeve  11 , which part extends beyond the end of the metal-jacketed connection line  19  in the plugging direction, is filled with a ceramic insulating mass  13 . A filling with a metal oxide would be just as suitable. The exact positioning of the contact element  12  is fixed, on the one hand, and the thermal and electric insulation from the connection sleeve  11  is ensured, on the other hand, by the filling. Not only the contact area  15 , but other areas of the wire end  14  and of the contact element  12  are also embedded in the ceramic insulating mass in the exemplary embodiment being shown, which makes the manufacture of the counterplug  10  especially simple. 
     At a plug-side section of the connection sleeve  11 , a second sleeve  20  made of metal, which extends in the plugging direction both beyond the connection sleeve  11  and the plug-side end of the contact element  12 , is fastened in the direction extending at right angles to the plugging direction, surrounding said connection sleeve  11 . Even though a strong holding force is exerted between the high-temperature patch plug  50  and the counterplug  10  even at high temperature especially if contact elements made of steel are used, securing the plug-in connection by means of the second sleeve  20  is advantageous. This is made possible by the fact that a section of the wall of the second sleeve  20 , which said section is not in contact with the connection sleeve  11 , is designed as a tongue  21 , which has a recess  22 . As will be described in more detail below on the basis of  FIGS. 4   a  and  4   b , a locking connection is made hereby possible between the high-temperature patch plug  50  and the counterplug  10 . The plug-side edge of the second sleeve  20  is advantageously bent slightly to the outside, i.e., in the direction at right angles to the plugging direction in order to form an insertion aid for the high-temperature patch plug  50 . 
     This novel combination of counterplug  10  and high-temperature patch plug  50  makes possible a hitherto unknown, very simple and comfortable procedure in manufacturing the plug-in connection. After the counterplug  10  has been supplied, only a section of the inner conductor  61  must be exposed at the plug-side end of the connection line  60 , which said section is then brought, e.g., by crimping or soldering, into electric contact with the contact element  64  of the counterplug. The connection line thus connected to the contact element  64  must then only be pushed in through the insertion opening  63  of housing  51  until stop spring  55  locks with the locking step  53 . The contact element  64  of counterplug  50  is thus fixed between the locking step  53  and the plug-side wall of housing  51  and the high-temperature patch plug is assembled completely. To finish the plug-in connection, only the housing  51  must be pushed into the second sleeve  20  of the counterplug  10  until the detent  52  locks into recess  22 . Contact element  12  of the counterplug  10  is now brought at the same time into electric connection with contact element  64  of the high-temperature patch plug  50 . 
     Separation of the plug-in connection is just as simple. Tongue  21  of the counter plug  10  is raised for this, e.g., by means of a screwdriver, so that the detent  52  is released. The counterplug  10  and the high-temperature patch plug  50  can then be pulled apart. It is possible in the same manner to push back the stop spring  55  of the contact element  64  by inserting a correspondingly shaped object through the duct opening  65  into the duct  56  and to make it possible hereby to pull out the contact element  64 . 
     While specific embodiments of the invention have been described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. 
     APPENDIX 
     List of Reference Numbers 
     
         
           10  Counterplug 
           11  Connection sleeve 
           12 ,  64  Contact element 
           12   b  Square section 
           13  Ceramic insulating mass 
           14  Wire end 
           15  Contact area 
           16  Metal jacket 
           17  Insulating embedding 
           18  Wire section 
           19  Metal-jacketed connection line 
           20  Second sleeve 
           21  Tongue 
           22  Recess 
           50 ,  80 ,  90  High-temperature patch plug 
           51 ,  81 ,  91  Housing 
           52  Detent 
           53  Locking step 
           54 ,  58 ,  68 ,  69  Clamping leg 
           55  Stop spring 
           56  Duct 
           57 ,  83 ,  93  Passage opening 
           59  Interior 
           60  Connection line 
           61  Inner conductor 
           62  Mounting area 
           63  Insertion opening 
           65 ,  84 ,  94  Duct opening 
           66  Surface of locking step 
           67  Wall 
           70 ,  71  Metal strip 
         P Parallel to the plugging direction extending through the center of an insertion opening

Technology Category: 5