Patent Publication Number: US-7909658-B2

Title: Plug for photovoltaic connector cable

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the US national phase of PCT application PCT/DE2008/000049, filed 11 Jan. 2008, published 25 Jun. 2009 as WO2009/076916, and claiming the priority of German patent application 102007060573.2 itself filed 15 Dec. 2007, whose entire disclosures are herewith incorporated by reference. 
     FIELD OF THE INVENTION 
     The invention concerns a plug-type connector, particularly for photovoltaic connector cables, with a plug having a grip, at least one snap formation effective in a plug-in direction, and a contact holder, and with a socket having a grip forming a contact-holder seat and an opposite snap formation that cooperates with the one snap formation and that together with the one snap formation secures the plug and the socket in a plugged-in condition, the contact holder and the contact-holder seat being formed with complementary positioning means that make insertion of the plug into the socket only possible when the one snap formation is aligned with the opposite snap formation. 
     BACKGROUND OF THE INVENTION 
     Generic plug-type connectors have been used by applicant in obvious prior public use for some time in the area of photovoltaic connection technology. These are single-pole plug-type connectors with which cables are connected that conduct electricity from solar panels. For safety reasons, the plug and socket of the plug-type connector have snap formations that are designed on the plug as two snap-in tongues and on the socket as snap seats that cooperate with the snap-in tongues. 
     In order to ensure during installation that in the plug-in process, the plug can be inserted into the socket only with the snap-in tongues fitting with the snap seats, the plug and socket are provided with positioning means. 
     In a specific embodiment, the socket has an essentially cylindrical contact-holder seat that has two inwardly projecting insets located diametrally opposite each other offset by approximately 180° relative to the plug-in direction that decrease the inner cross-sectional area of the contact-holder seat by forming secantal faces. 
     An essentially cylindrical contact-holder seat that is oriented in the plug-in direction has cut-outs that are complementary to the insets of the socket, so that the plug can only be introduced into the socket when the secantal faces on the plug and on the socket are aligned with each other. This orientation that ensures the snap-in process in the plug-type connector of plug and socket is particularly advantageous in the assembly in positions that are difficult to access. Thus, the plug-in process can take place blind, a safe orientation of the snap formations toward each other being ensured without exception. 
     The described plug-type connector has been tested many times, however, with respect to its handling, it is seen as being in need of improvement. 
     OBJECT OF THE INVENTION 
     The object of the invention is to provide a plug-type connector that especially improves the plug-in of plug and socket without having to be observed and thus significantly improves the ease of installation. 
     SUMMARY OF THE INVENTION 
     This object is attained by a plug-type connector wherein one of the positioning means of the plug or socket is provided with a guide formation that works together with an opposite guide formation of the socket or plug so that during the plug-in process the plug and socket are forced to move relative to each other to assume the aligned position of the positioning means. In the prior art, specifically a plugging process for positioning means that are not aligned toward each other, such as for example, the previously described secantal faces, was not possible. In order to make the plugging process possible, however, the positioning means had to be aligned with each other as a result of active relative rotation of the plug and socket by the installer. Only then was it possible to establish a plug-in connection. 
     The necessity of an active alignment of the positioning means toward each other is eliminated by the guide formations according to the invention. If plug and socket are put together with positioning means that are not aligned with each other, the one guide formations and opposite guide formations work together in such a way that at the start of the plug-in motion, the plug and socket automatically align with each other in such a way that the positioning means are in aligned position. A to and fro motion of plug or socket by the installer is thus eliminated, the correct alignment of plug and socket takes place automatically in the plug-in process as a result of the forced guiding initiated by the guide formations and opposite guide formations. This makes installation of the plug-type connector in accordance with the invention immensely easier, particularly when plug-in is performed without benefit of vision. 
     It is conceivable that the positioning means of the contact-holder seat is designed as at least one inset oriented in the plug-in direction that reduces the area or the horizontal cross section and that the contact holder has at least one cut-out complementary to the inset, and for positioning of snap formations and opposite snap formations the inset and cut-out face each other during the plug-in process, particularly when the inset forms a secantal face with respect to the contact-holder seat and the cut-out forms a secantal face with respect to the contact holder and for positioning of snap-in and opposite snap formation, the secantal faces of contact holder and contact-holder seat face each other. 
     The at least one inset has a front end face that confronts the contact holder that is provided with an angled opposite face that is angled relative to the plug-in direction and that the outer-surface region bordering on the at least one cut-out on the contact holder is provided with an angled guide edge, and that the angled guide edge and the angled opposite face work together like a thread during the plug-in process and the plug and the socket are forced to rotate relative to each other up to the aligned position of inset and cut-out. 
     The previously described plug-type connector basically uses the positioning means that are already known from the prior art. On the inset, only the shape of the front end face that was already available in the prior art was modified. This does not affect the inner areas of the cylindrical contact holder. 
     The angled guide edge on the contact holder must consequently be designed in such a way that the outer circumference of the contact holder is not expanded. The angled guide edge is therefore realized by a corresponding material removal, the outer circumference of the contact holder being partially reduced. In the transition section, the contact holder forms a shoulder that forms the angled guide edge. 
     In other words, the angled guide edges and angled opposite faces or, formulated more abstractly, the one guide formations and opposite guide formations do not have an effect on the geometric congruence of contact holder and contact-holder seat of the prior art, so that the new plug-type connector is plug-in compatible with the existing plug-type connector of the applicant. With respect to service and maintenance of existing photovoltaic connector cables or the extension of existing installations, this is a significant advantage, as no components of older plug-type connectors have to be exchanged or adapted. 
     A preferred embodiment is characterized in that it is provided with a contact holder that is offset by approximately 180° at the circumference relative to positioning means located toward each other in the form of insets that work together with corresponding cut-outs on the contact-holder seat. 
     When using two insets arranged corresponding to each other, the maximal path of rotation of plug and socket toward each other can be limited up to the aligned position of inset and cut-out to a maximum of approximately 180°. 
     In a particularly preferred embodiment, the plug-type connector is developed further so that each inset has a front end face that confronts the contact holder, that is provided with two angled opposite faces that are directed toward each other roof-shaped, sloping in the plug-in direction, and that each outer-surface region bordering on the at least one cut-out on the contact holder is provided with two angled guide edges oriented arrow-like toward each other in the plug-in direction, and respectively one angled guide edge and one opposite angled edge that work together in the plug-in process like a thread and force the plug and socket to rotate relative to each other into the aligned position of inset and cut-out. By means of two angled guide edges with complementarily angles, rotation in two directions is possible. Additionally, when using two positioning means that are offset with respect to each other at the circumference by approximately 180°, the maximum rotation path is shortened to 90°. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       Additional advantages of the invention as well as a better understanding follow from the description of preferred embodiments in conjunction with the drawings. Therein: 
         FIG. 1  shows a plug-type connector in accordance with the invention in plugged-in condition, 
         FIG. 2  shows a plug-type connector according to  FIG. 1  in unplugged condition, 
         FIG. 3  is a detail view of the plug shown in  FIG. 2 , 
         FIG. 4  is a large-scale view of the detail indicated at circle III in  FIG. 3 , 
         FIG. 5  shows the plug of  FIG. 3  in an alternative view, 
         FIG. 6  is a large-scale view of the detail indicated at circle V in  FIG. 5 , 
         FIG. 7  is a detailed view of the socket according to  FIG. 2 , 
         FIG. 8  is a large-scale view of the detail indicated at circle VIII in  FIG. 7 , 
         FIG. 9  is an alternative view of the socket shown in FIG. 
         FIG. 10  is a large-scale view of the detail indicated at circle IX in  FIG. 9 , 
         FIG. 11  shows a plug-type connector according to  FIG. 2  with snap units offset by 90° with respect to each other on the plug and socket, 
         FIG. 12  shows the starting plug-in process with snap units offset with respect to each other by 90° on the plug and socket according to  FIG. 11 , 
         FIG. 13  is a schematic illustration of a contact holder on the plug and a contact-holder seat on the socket in alternative, simplified embodiment, 
         FIG. 14  shows a simplified contact holder on the plug according to  FIG. 13  in alternative view, 
         FIG. 15  shows a plug-type connector according to  FIG. 12  with a socket graphically opened up to permit a view of the positioning means, 
         FIG. 16  shows a plug of a plug-type prior-art connector, 
         FIG. 17  is a large-scale view of the detail indicated at circle XVI in  FIGS. 16 , 
         FIG. 18  shows a socket of a plug-type prior-art connector, 
         FIG. 19  is a large-scale view of the detail indicated at circle XVIII in  FIG. 18 , 
         FIG. 20  is a cross section through a plug-type prior-art connector with a view in the plug-in direction of the socket and positioning means of the contact holder and contact-holder seat offset with respect to each other by 90°. 
         FIG. 21  is a cross section like  FIG. 20  with aligned positioning means of the contact holder and contact-holder seat. 
     
    
    
     SPECIFIC DESCRIPTION 
     In the figures, a plug-type connector is identified throughout at  10 . The plug-type connector comprises a plug  11  and a socket  12 .  FIGS. 1 to 15  show the plug-type connector in accordance with the invention or its plug  11  and socket  12  in various views, whereas  FIGS. 16 to 21  show a plug  11  and a socket  12  according to the prior art as they have previously been sold by applicant. 
     The drawings illustrating the prior art and those of the plug-type connector  10  according to the invention show analogous construction components with identical references. In the following, first, the prior art according to  FIGS. 16 to 19  will be discussed. 
     The plug  11  of the plug-type connector  10  from the prior art comprises a grip  13  from which a central, essentially cylindrical tubular contact holder  14  extends in a plug-in direction x. Adjacent a contact-support base  15 , two annular ridges  16  are located spaced from each other in the plug-in direction to form a groove  17  for a gasket, particularly an unillustrated O-ring. 
     From the grip  13 , which is provided with two opposite recessed grip recesses  18  further extend two opposite snap-in tongues  19  that flank the contact holder  14  and whose outer ends  20  point in the plug-in direction and are provided with snap barbs  21  that are wedge-shaped in the plug-in direction x and tapered toward the contact holder  14 . 
     The contact holder  14  is essentially a cylindrical tube having a central bore  22  holding an unillustrated contact. At two opposite sides, the contact holder  14  is formed with cut-outs  23  as a result of material removal that serve as positioning means for the contact holder. As a result of the cut-outs  23 , the otherwise cylindrical contact holder  14  has secantal faces  24  that extend from the last ridge in the plug-in direction x up to a—in the plug-in direction x—contact-support outer end  25 . The secantal faces  24  each primarily point toward a respective one of the snap-in tongues  19 . 
     In  FIGS. 18 and 19 , views of the socket  12  of the prior art are shown. Here the socket  12  is also provided with a grip identified at  40  and provided with two grip recesses  41  that are opposite each other. An outer end  42  of the socket  12  that is forward in the plug-in direction x has a front end face  52  at which open holes  43  of snap seats  44  that cooperated with the snap-in tongues on the plug. The snap seats  44  are opposite each other and flank a generally cylindrical contact-holder seat  45  formed by the grip  40  of the socket  12 . 
     The snap seats  44  end in the respective slots  46  that are oriented perpendicular to the plug-in direction x, in which in plugged-in condition—engaging behind the respective snap seat  44 —the snap barbs  21  of the plug  11  are held to lock the plugged-in condition. 
     The contact-holder seat  45  has two parts. Forward in the plug-in direction x it forms a sealing part  47  that merges with a somewhat narrower seat  48  for the contact holder  14 . 
     The seat  48  extends in the plug-in direction x into the grip  40  of the socket  12  and has two insets  49  that are located opposite each other. The insets  49  form relative to the cylindrical horizontal cross section of the seat  48  secantal faces  50  that extend along the entire plug-in direction x the full length of the seat  48  and that are parallel to each other. The secantal faces  50  of the insets  49  are each positioned opposite a respective one of the snap seats  43 . 
     In  FIG. 21 , a cross section of the plug-type connector  10  is shown. The cross-section plane is parallel to the front end face  52  of the socket  12  and is located in the joint between the plug  11  and the socket  12 .  FIG. 21  is shown simplified to the extent that the snap-in tongues  19  of the plug  11 , as well as the annular ridge  16  of the plug  11  are not shown. With respect to the plug, only the contact holder  14  that is in seat  48  is shown. 
     As can easily be seen in  FIG. 21 , the plug  11  can only be inserted into the socket  12  when the secantal faces  24  and  50  of the contact holder  14  and the seat  48  are aligned with each other. During the plug-in process, the secantal faces  24  and  50  slide on each other. In the prior art, the secantal faces  24  and  50  of the cut-outs  23  and the insets  49  thus serve as positioning means that only permit plugging-in when the snap-in tongues  19  are aligned with the snap seats  44 . This ensures that even when plugging in without looking, the snap formations  44  and  19  engage with each other upon at the end of the plug-in process and lock in the plugged-in condition of the plug-type connector  10 . 
       FIG. 20  also shows a cross-sectional view of the prior-art plug-type connector  10  on a section plane that is identical to that in  FIG. 21 . In this orientation of the secantal faces  24  of contact holder  14  relative to the secantal faces  50  (shown as dotted line) of the seat  48 , the plug  11  is in a position that is offset by 90° with respect to socket  12 . In this position, front end faces  51  extending parallel to the confronting faces  52  of the socket  12  at the insets  43  prevent entry of the contact holder  14  into the seat  48 . The plug-in process can thus not be concluded. 
     In this and in every other case, so long as the secantal faces  24  and  50  are not congruent or aligned to each other, the installer who is putting together the plug-type connector  10  must relatively rotate the plug  11  and the socket  12  around a longitudinal plug-connector axis L until the congruent position of the secantal faces  24  and  50  is found. Only then can the contact holder  14  be inserted into the seat  48  and the plug-in process can be completed. 
       FIGS. 20 and 21  show in particular how the position shown in all the figures of the secantal faces  24  and  50  that are designed as positioning means is not decisive relative to the snap formation designed as snap seat  44  or snap-in tongue  19  for the forced alignment toward each other of plug and socket. Rather, it is critical that the relative position of the positioning means of the plug or the socket are identical with the plug or socket snap formation in plug  11  and socket  12 . 
     The invention is explained in the following with reference to  FIGS. 1 to 15 . The embodiment of the plug-type connector  10  according to the invention is identical with the previously described prior art in many characteristics and construction components. To that extent, the repetition of a basic description of the plug-type connector  10  with plug  11  and socket  12  is dispensed with and reference is made to the above explanations concerning the prior art. 
       FIG. 1  shows a plug-type connector  10  according to the invention in plugged-in condition, in  FIG. 2  it is shown in unplugged condition. The longitudinal plug-connector axis L that is shown in  FIG. 1  for the first time and which is, however, analogous to the prior art, extends through the center of the plug-type connector  10  and is parallel to the plug-in direction x. 
       FIGS. 3 and 4  are analogous to  FIGS. 16 and 17  and show the plug  11  in an overall view, as well as the outer end  25  of the contact holder  14  of the plug  11  in a large-scale view. Identically functioning components of the plug  11  shown in  FIG. 3  with the plug  11  of the prior art according to  FIG. 16 , have been provided with the same references. 
     Particular attention is to be paid to the contact holder  14  in the plug  11  that is modified in accordance with the invention. In its essentially cylindrical form and in its basic geometry, it is like the contact holder  14  of the prior art and consequently also has a cut-out  23 . As a result, the contact holder  14  in  FIGS. 3 to 6  also is formed with a pair of secantal faces  24  that point toward the snap-in tongues  19  and extend along the entire length of the contact holder  14 . 
     Contrary to the prior art, the contact holder outer end  25 , however, is significantly changed. Outer-surface regions  26  between the cut-outs  23  or the secantal faces  24  they form have been provided with guide formations  27 . As the result of a partial material removal in the contact holder outer end  25 , the outer-surface regions  26  form to the plug-in direction x or to the longitudinal plug-connector axis L diametrally opposite aligned pairs of angled guide edges  28 . These extend approximately in the transition section between the secantal faces  24  and run arrow-like or roof-like toward each other in the plug-in direction x. Each angled pair of guide edges  28  of each outer-surface region  26  meets to form at the contact holder front end face  29  an intersection  30  that is offset angularly by about 90° to the secantal faces  24 . 
       FIGS. 7 to 10  show the socket  12  in accordance with the invention in various views or sectional enlargements. Even the socket  12  in accordance with the invention is designed identical to socket  12  of the prior art in its essential components according to  FIGS. 18 and 19 . 
     As a first important difference it is striking that in the socket  12  according to the invention, snap-seat side walls  53  extend continuously up to the level of the snap slot  46  and form therewith the sides of a snap seat  54 . This has the important advantage that the previous manual engagement in the snap slots  46  is no longer possible and the snap connection between the plug  11  and socket  12  can only still be worked on with tools. In order to make manual actuation even more difficult, a window  55  has been provided outside the snap unit seat  54  to make the engagement opening  56  even smaller. 
     Like the socket  12  already known from the prior art, the socket according to the invention  12  as per  FIGS. 7 to 10  has the two diametrally opposite insets  49  in the seat  48 , which form the secantal faces  50  in the cylindrical cross section. These faces  50  extend in the plug-in direction x along the entire length of the seat  48 . The contact-holder seat  45  or the seat  48  of the socket in accordance with the invention thus corresponds in its essential geometry to the socket  12  of the prior art. 
     The only change on the socket, which is, however, essential for the invention, concerns the front end faces  51  of the insets  50  [ 49 ]. Whereas they are flush with the front end face  52  of the socket in the prior art, in accordance with the invention they now form opposite guide formations  57  that cooperate with the guide formations  27  of the contact holder. 
     These guide formations  57  are designed as opposite angled edges  58  according to the invention. These are aligned diametrally oppositely to the longitudinal plug-connector axis L and form a V-shape pointing in the plug-in direction x. The apex formed by the V-shaped angled edges  58  is level with a shoulder  59  formed at the cross section reduction from the sealing section  47  to the seat  48  the of contact-holder seat  45 , i.e. at the end of the seat  48 . In  FIGS. 11 to 15 , the process of plugging the plug  11  into the socket  12  is shown. This shows clearly how, with the help of the angled guide edges  28  and opposite angled edges  58 , automatic alignment of the secantal faces  24  and  50  is achieved in the plug-in process. 
     In  FIG. 11 , the beginning of the insertion process is illustrated. The plug-in tongues  19  of plug  11  are angularly offset by approximately 90° with respect to the snap seats  44 . This alignment corresponds approximately to the illustration in  FIG. 20  of the prior art, in which the insertion process was previously blocked in order to prevent snap-in and thus an unsafe plug-in connection of plug  11  and socket  12 . 
     In  FIG. 12 , the contact holder  14  is already partially inserted into the contact-holder seat  45 . 
       FIG. 15  shows the plug-condition of  FIG. 12 . The snap-in seat  44  of socket  12  that is turned toward the observer is broken away in the drawing. Thus, one can see the unreferenced contact-holder seat  45 . In contrast to the prior art, according to  FIG. 15 , planar faces do not abut each other approximately parallel to the front end face of socket  52  or the contact-holder front end face  29  and stop the insertion movement. Instead, the now angled guide edges  28  and opposite angled edges  58  meet and engage thread-like. As a consequence, the plug rotates around the longitudinal plug-type connector axis L toward rotation y, which is not shown in  FIG. 15 , until the secantal faces  24  and  50  on the plug and on the socket are aligned with each other. As a result, the snap formation  19  and  44  of plug  11  and socket  12  are also aligned toward each other in the plug-in direction x and are thus aligned axially with each other. Nothing impedes further insertion movement in the plug-in direction x. 
     In  FIG. 15 , the advantage of the diametrally opposed pairs of angled guide edges and angled opposite faces  28 ,  59  can be seen. Depending on which pair of faces meet each other, the insertion movement also leads to a rotation counter to the direction of rotation y. Thus, the shortest rotating motion is always executed to ensure the correct positioning of the plug  11  and socket  12 . 
     When the inset  49  and the outer-surface region  26  form the two angled guide edges  28  or angled opposite faces  58 , they meet at a point. It is advantageous to locate the points of two angled guide edge pairs  28  or two angled opposite faces  58  at least minimally circumferentially asymmetrical on the contact holder  14  or in the seat  48 . This ensures that the angled edges  28 ,  58  always meet each other in a plug-in process, but never the points, so that the required rotation that is required for positioning plug  11  and socket  12  is always induced. 
     In order to make the plug-in process visually clear once more,  FIGS. 13 and 14  show schematic representations of an alternative embodiment of simplified construction. 
     A cylindrical contact holder sleeve  60  has a single bar-like radially inwardly projecting inset  61  with an angled face  63  that is directed axially toward the schematically shown contact holder  62 . 
     The contact holder  62  has a cut-out  64  inset from an outer-surface region  65  and forming an angled guide edge  66  directed axially toward the contact-holder sleeve  60 . Based on its longitudinal extension alone, the similarity with a thread section is clear. The inset  61  and cut-out  64  form, as already described, complementary secantal faces  67 . The angled guide edge  66 , which extends from the contact holder front end face  68  opposite the plug-in direction x, is formed by machining of contact holder  42  [ 62 ] to a thickness equal to the maximum thickness of inset  61 . This is also analogous to the previous embodiment. 
     If now, during the plug-in process the angled guide edge  66  meets the angled opposite face  63 , the contact holder  62  then rotates around its own axis until the secantal faces  67  of the contact holder  62  and the contact-holder sleeve  60  are axially aligned with each other and the necessary position has been reached. 
     In sum, the principle of the invention can be abstracted to the effect that at least one of the positioning means of the plug  11  or socket  12  (here the inset  49  or  67 ) is provided with a guide formation that works together with an opposite guide formation that is located complementarily in the socket  12  or plug  11 . 
     The interaction of the guide formations leads to an automatic alignment of the positioning means of the plug and the socket during the plug-in process. In contrast to the prior art, this has the important advantage that the installer does not have to actively rotate the plug  11  or socket  12  until they are positioned correctly toward each other and can be plugged into each other, but only simply needs to perform the plug-in process. The specific embodiment in  FIGS. 1 to 12  and  15  was provided with guiding sections in such a way that it is plug-compatible with the prior art shown in  FIGS. 16 to 21 . This has the important advantage that during service, maintenance or expansion of existing solar plants, a uniform plug system continues to exist, even if in mixed use of plugs  11  or sockets  12  in accordance with the invention together with prior-art plugs  11  or sockets  12 , the advantages according to the invention are not necessarily realized. A socket  12  that is designed according to the invention makes it possible, even in connection with a prior-art plug  11  to induce the advantageous rotating motion for positioning, even if because of the sloped guide edges  28  that are absent on the plug, the rotating motion y is not induced in every relative position of plug  11  and socket  12 .