Electrical plug-in connector

[0001] 1. Field of the Invention

[0002] A quick-fastening plug and socket arrangement includes a locking sleeve arranged concentrically between the plug and the circular socket opening within which the plug is axially inserted, which locking sleeve includes a resilient projection that is radially biased outwardly into locking engagement with screw threads carried by the inner circumferential surface of the socket opening. The locking sleeve is connected against longitudinal displacement relative to an associated one of the plug and socket members, said sleeve being rotatable relative to the associated plug and socket member, thereby to release the plug for removal from the socket opening.

[0003] 2. Description of Related Art

[0004] It is well known in the patented prior art to provide various plug and socket arrangements, as evidenced, for example, by the prior U.S. patents to Bury U.S. Pat. Nos. 7,059,891 and Schumacher et al No. 7,207,824, among others.

[0005] Many different embodiments are known for electrical plug connections of this kind. On the one hand, cables, equipped with the corresponding structural parts, can be connected with each other via such a plug connection; likewise, depending upon the design, several connections can be connected to a distributor with one plug part which distributor, in turn, is equipped with a plurality of socket counterparts to the plug parts.

[0006] The plug connections under discussion here permit a secure connection in the area of the connection points because the plug member, on the one hand, and the socket member, on the other hand, are secured via a thread-like connection with each other. In the simplest case, the plug members are equipped with a sleeve that has an outer projection that defines a so-called thread. Such designs make it necessary, after the plug contacts have been brought together, to produce a screw connection over the entire thread length. This implies by no means inconsiderable time expenditure, especially when one makes a plurality of such plug connections. Connections on distributors used in automation technology are often arranged relatively closely to each other, something that also adds to the time expenditure and makes the connection operation relatively laborious.

[0007] Therefore, plug members and corresponding socket members have been proposed which facilitate the insertion of the sleeve, on the plug side, into the socket member by simply pushing it in and, at the end of the assembly procedure, by means of a slight turn, permitting a final and axial retention between the two structural parts. But there is one disadvantage here: Designs used in the past necessitate expensive production and processing both of the sleeve of the plug part as well processing of the socket member, since currently known designs are based on the idea that [they] contain either bayonet-like connection possibilities or that both the sleeve of the plug part as well as the socket member are provided with unthreaded areas that extend in the axial direction, which facilitate an axial assembly or plugging-in, without any need for a turn and which only at the very last moment permit axial retention by turning. In the latter variant, a connection is made to an interior thread which is not provided with the axially free areas; in that case, one can furthermore not save any time when compared to the known screw connections.

[0008] Accordingly, a primary object of the present invention is to provide a quick-connect plug and socket arrangement including a locking sleeve arranged concentrically between the plug and socket members, said locking sleeve carrying resiliently biased projection portions that engage screw thread means provided on the adjacent circumferential surface of either the plug or the socket member, thereby to permit linear axial insertion of the plug into the socket, while locking the plug against axial removal from the socket opening. In the preferred embodiment, the screw thread means are provided on the inner circumferential surface of the socket opening, and the projections are biased radially outwardly from the locking sleeve. In an alternative embodiment, the screw thread means are provided on the outer circumferential surface of the plug, and the projecting portions a biased radially inwardly from the locking sleeve. In either case, the locking sleeve is connected against longitudinal displacement relative to the associated plug or socket member.

[0009] According to a more specific object of the present invention, the tubular locking sleeve is formed by punching and bending from a resilient metal sheet. A plurality of circumferentially-spaced locking projecting portions are formed by stamping the blank with U-shaped openings that define integral tongue portions that carry the projections at their free extremities. In one embodiment, the tongue portions are biased radially outwardly for engagement with the screw threads on the socket opening circumferential wall surface. In a second embodiment, the tongue portions are biased radially inwardly to effect engagement between inwardly projections on the tongue portion and screw thread means on the outer circumferential surface of the plug member.

[0010] The present invention was developed to provide a plug connection including plug and socket members such that one can bring about a particularly simple and fast connection with low production costs. The invention first of all provides an electrical plug connection with a plug member provided with a rotatable sleeve, for connection with a socket member that has an interior thread, whereby the sleeve, on its outer circumferential area, that engages the socket member, is provided with at least one deflectable, preferably resiliently deflectable projection that is fashioned in the manner of a part of an external thread turn.

[0011] As an alternative, in its internal circumferential area which receives the sleeve, the socket member is equipped with at least one deflectable, preferably elastically deflectable projection that is fashioned in the manner of an interior thread turn. Here, the sleeve is provided with an outer thread for connection with the socket member.

[0012] The present invention accordingly also creates a plug member for an electrical plug connection of the kind according to the invention, where the sleeve, on its outer circumferential area, engaging the socket member, is equipped with at least one deflectable, preferably resiliently deflectable projection fashioned in the manner of a part of an outer thread turn, as well as a socket part or socket member that, in its internal circumferential area that receives the sleeve, is equipped with at least one resiliently deflectable projection fashioned in the form of a part of the interior thread turn.

[0013] The terms plug member and socket member here relate not only to the electrical contacts, but especially to the screw connection with outer thread (plug part) and interior thread (socket part).

[0014] According to a preferred embodiment, the invention thus creates a plug member with a locking sleeve that can be made in a simple and inexpensive manner, for the fast and uncomplicated connection with a socket member, whereby the socket member can comply with the general industrial standard (for instance, according to the “M” standard, for instance, “M12” or “M8”, or the like). In this case, the socket member is in the known manner provided with an interior thread. This embodiment is particularly preferred.

[0015] Similar advantages can be achieved when the socket member has a sleeve provided with projections and thus does not have a customary interior thread. In this case, the plug part is provided with an outer thread in the known manner.

[0016] The plug member of the present invention, with the shaped sleeve, can, in the axial direction, without any problem, be pushed into a socket member provided with an interior thread, because the projection or the projections can overcome the thread turns of the interior thread by virtue of their resilient capacity, but, at the same time, in each plug insertion state, become locked in a thread turn of the interior thread. After the sleeve has been pushed in axially, the sleeve can still be turned slightly in the way of a screw connection in order to fix a final assembly position. The turn required for this purpose is comparatively minor so that corresponding plug connections can be assembled extremely quickly and securely, specifically, also in poorly accessible installation situations and in case of a relatively tight arrangement of the connections.

[0017] The sleeve can be made easily and cheaply, because the only important thing here is to mold upon the sleeve at least one projection that forms a part of an outer thread turn. The elastic elements furthermore create a permanent vibration safety.

[0018] A development of the basic idea behind the invention, which can also be considered as an independent invention of its own, provides that the sleeve is made as a punch-bending part consisting of sheet metal. This offers the advantage that the locking sleeve need not have to be made as expensive turning part or by means of forming or casting; instead, it can be made by means of simple punching and bending procedures. It is furthermore possible, in this way, to apply this sleeve also upon the actual interior parts as part of a second production step so that these interior parts need not have to be extrusion coated.

[0019] Other production methods are conceivable, for instance, an embodiment as a synthetic plastic composite part or production from a type or design as a solid synthetic plastic part.

[0020] The plug member can also be installed fixedly on a housing, for example, a housing of a distributor. In this case, the socket member is mounted upon the fixedly installed plug part, which socket member can have a conventional interior thread. All of the above advantages are also implemented in this particular modification.

[0021] According to another advantageous modification, one can also reduce the time required for undoing the connection when compared to known connections, specifically, when the projections are not so arranged on the plug part or socket part that they engage the thread turn of the corresponding thread which is last in the axial plug-in directions, but instead, engage one of the first thread turns in the axial plug-in direction, for example, they engage in one of the first four, in particular, the second thread turn, because now one needs only a number of thread turns that would correspond to the number of rotation motions needed for separation. The plug part or socket part can be designed for assembly upon a housing or for connection to a cable.

[0031] In FIG. 1 to 3, the reference symbol 1 generally designates a plug connection arrangement which comprises a plug member 2 and a socket member 3 which can be plugged together linearly in the axial direction, as oriented and guided by guide means 20 (FIG. 4). The plug and socket members are equipped with corresponding first and second contacts 2a, 3a that in this case are made as pins 2a and corresponding sockets 3a. Plug member 2 has a cylindrical interior body 13 preferably consisting of an electrically-insulating synthetic plastic material, with the first contacts 2a, and the socket member 3 also has an interior body 14 consisting of electrically-insulating synthetic plastic material, with the second contacts 3a, whereby, in this case, the interior body of the socket 3 can be plugged, in its axial terminal area, into the internal body of plug member 2.

[0032] The plug member is equipped with a concentrically mounted locking sleeve 4 that is connected against longitudinal displacement relative to the plug member 2 by radially outwardly directed integral projections 2b that extend within an annular bulge portion on the sleeve externally of the socket member. The sleeve is connected for rotation with respect to the interior plug area 3b, which sleeve serves to establish a connection between plug member 2 and socket member 3. For this purpose, socket member 3, in the area of an outer sleeve portion 15, is provided on its inner circumferential surface with an interior thread 5 (FIG. 3), and sleeve 4 in its outer circumferential area adjacent the socket member 3 is provided with at least one radially outwardly elastically deflectable or resilient projection 6 that engages part of an outer thread turn, whereby this projection 6 or several such projections 6 are supported to engage one thread turn of the interior thread 5 of the socket member 3. This situation is illustrated clearly in FIG. 3.

[0033] As one can clearly see in FIGS. 4a, 4b and 5, locking sleeve 4 is provided in its outer circumferential area engaging the socket member 3 with a total of three projections 6. These projections 6 in each case form parts of a thread turn and, in the exemplary embodiment illustrated, are arranged in a manner staggered by about 120° with respect to each other. Besides, these projections 6 lie on a line of a thread turn whereby here naturally as an alternative it would also be possible to arrange the projections 6 as being staggered and offset relative to each other in the axial direction of sleeve 4, whereby the projecting portions engage different threads of the screw thread means 5. These figures furthermore make it clear that the projections 6 in each case at formed at the extremities of resilient tongue portions 6a defined in the locking sleeve by stamped U-shaped cut-outs 7, so that the resiliency of these projections 6 is guaranteed without any obstacle. Projections 6 are so oriented and are so inserted, in the plug-in direction, radially from the inside to the outside, that the plug part can be quickly pushed into the interior thread 5 of the socket member 3, whereby projections 6 are bent inwardly, whereas, on the other hand, in the opposite direction—in other words, during drawing—they block or lock, so that, for purposes of separation, they have to be turned so that they can be released. A terminal edge 17 of projection 6 is so bent outward that it, in a defined manner, engages an individual thread turn of the interior thread of the socket member. Except for projections 6, there is no outer thread present on the locking sleeve 4.

[0034] Additional projections, for example, those turned by 90° (not illustrated here), can also be used to make a kind of thread retention in the manner of additional springs, so that they will be blocked against becoming loosened as a result of turning 2 (not illustrated here).

[0035] In general, locking sleeve 4, in this case, in a preferred embodiment, is made advantageously as a punch-bending part consisting of resilient sheet metal, something that is particularly cheap and simple. In assembling the sheet metal strip, the latter need not be closed to form a complete tube, although this is conceivable; instead, a narrow slit 12 can be left also in the assembled state. Other embodiments are also conceivable, for example, they can be formed made from a piece of tubular stock.

[0036] FIGS. 6 and 7 show a blank which initially still lies flat and which in FIG. 7 is already partly bent into a cylindrical form, for the production of a corresponding sleeve 4. The blank is labeled 4a in FIGS. 6 and 7. Here we can clearly see again the projections 6 and the U-shaped stampings 7, within which lie the projections 6. Besides, FIGS. 6 and 7 clearly show that the particular blank, on its side facing away from the projections 6, is provided with an upper front edge with an annular molded-on bulge 8 portion containing circumferentially spaced penetration openings 9. As a result, sleeve 4 is also made with a bulge 8 and with the penetration openings 9, which make it easier to put on a tool for the purpose of rotating the sleeve to permit separation of the plug from the socket. Naturally, if necessary, sleeve 4 can also be tightened manually into a secured position or can again be separated if disassembly should become necessary.

[0037] Sleeve 4, made as punch-bend part, can, after its production, be fashioned as a closed sleeve by connecting its two blank ends 4b, while it is also possible to have the two blank ends 4b not abut quite against each other so that sleeve 4 remains axially open to define a slit 12 that extends the length of the sleeve. The latter to that extent is not a disadvantage since the sleeve, in the connected state, engages the interior thread 5 of a socket member 3 anyway.

[0038] FIG. 8 shows a variation of the sleeve wherein, instead of being provided with a bulge 8, the sleeve 4 is provided with a knurled end portion 10, by means of which handling of the sleeve is made easier when screwing tightly or when separating a connection. This modification, for example, can be made by shaping from a piece of tubular stock. It does not have an axial slit 12. Separating tools of the same type can be placed both upon the bulge and also upon the knurling (in the manner of a wrench). Manual separation is also possible.

[0039] As shown in FIGS. 4a, 4b and 8, the locking sleeve 4, regardless of its usual design, on its front terminal area, that is associated with projections 6, engages the socket member 3 which is equipped with a compressible annular seal 11 that rests against the sleeve 4 in the assembled state, as one can clearly see in FIG. 3.

[0040] Plug part 2 with sleeve 4 can without any problem be pushed linearly (as guided by orientation means 20 (FIG. 4a) in the axial direction into the socket member 3 which is provided with the interior thread. After the sleeve has been pushed in axially, it can still be turned slightly in terms of a screw connection in order to fix a final assembly position. The connection is separated in the known manner by simply screwing it loose in the opposite direction.

[0041] FIG. 9 is a diagram showing an alternate embodiment of the invention; wherein the plug member 2 (indicated in the diagram only in terms of segments) is fashioned according to the industrial standard and has an outer thread 16 whereas, in this case, the socket member 3 is provided with a locking sleeve 4′ having a resilient projection 6′ which effectively serves in the manner of an internal thread turn segment. When the socket member is pushed linearly axially toward the plug member 2′, the projection 6′ is deflected outwardly, and when the plug reaches its final inserted position, the projection 6′ is biased radially inwardly toward engagement with a corresponding turn of the screw means 16 formed on the outer circumferential surface of the plug member 2′. In the assembled state, the resilient biasing force in the embodiment of FIG. 9 is directed radially inwardly, whereas, according to FIGS. 1 through 8, it works outward radially outwardly in the connected state. The sleeve is connected for rotation relative to the socket member, but is prevented from longitudinal displacement relative thereto.

[0042] While in accordance with the provisions of the Patent Statutes the preferred forms and embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that changes may be made without deviating from the invention described above.