An important trend in the plug or cable connector field is to make the permanent electrical connection between insulated electrical connectors and the respective contacts of plugs, connectors, device sockets, sensor-actuator modules, printed-circuit modules, and the like as practical as possible, that is with minimal expense and time. A principal requirement is to make this connection manually without the use of tools and without error. In this regard expressions, such as for example “quick-connect contact” and “quick-connect coupling,” have been coined. The main contact systems are the press-fit system, the insertion system, the gripping system, and the spring-contact system. A further very important trend that is derived from the generally known technical developments is to miniaturize plugs and cable connectors, as a rule with the same load requirements. In this regard the most important solder-free electrical connection is the press-fit system.
Plug and socket fittings for plug connection are known that are formed by several subassemblies. These comprise at least one metallic or metallized casing that provides shielding t the cable end. In this manner the shielding of the cable is connected with the housing while the individual conductors of a normally multiconductor cable are each connected with a contact of the plug or socket by a press-fit connection. Such a known plug or socket has several disadvantages. First it is necessary to spread the shield wrap of the cable in order to fit the conductors within the shield wrap in a holder that in turn carries the press-fit connections. To connect the shielding with the housing there is a conical element over which the spread shielding is flattened and that is compressed against an abutment on assembly. As a result the assembly cost for such a plug or socket is not only high, but is error-prone since the shielding is often comprised of very thin filaments that are easily cut off by the inexperienced when the insulation jacket surrounding the shielding is removed to expose the shielding. This creates the danger that the shield braid is damaged or largely removed so that there is insufficient electrical contact with the compression cone and to the casing of the plug or socket and as a result the shielding is nonexistent or poor. An effective shield is absolutely essential in the transmission of high-frequency or high-data-rate signals. What is more, systems now require four separate lines. It has not been considered possible to convert such plugs that have a central contact, since standards require the outer contacts to be very closely spaced. The use of press-fit terminals and their insulating seats uses up the space that would be occupied by a central contact and thus limits the use of such plugs.
The known press-fit terminals or forks are flat. In order to generate the required contact forces, the contact arms just be relatively thick in the deflection direction and thus are blocky. This disadvantage is compounded by the fact that the press-fit terminals normally lie in planes that are perpendicular to the planes in which the wires extend to them or are deflected through them (EP 1,158,611). A further disadvantage of flat press-fit terminals is that they must be fitted in respective grooves formed in a block of insulating material that is also formed with guides for feeding in the wires. These seats fix the press-fit terminals in position and ensure that the arm edges cut through the wire insulation and are not deflected by it when the wires are jammed in place. As a result of the limited engagement face that these press-fit terminals have exposed in the deflection direction, considerable lateral pressure is exerted on the sides of the plastic seats and they can be damaged by it. This effect is particularly true for stamped press-fit terminals which have raw sharp-cornered edges.
It is an object of the invention to provide a shielded socket or plug having press-fit terminals where the electrical connection between the shielding of the cable and at least one part of the casing of the plug or socket is of relatively simple construction, forms a solid connection, and is not expensive to put together.
This object is attained by the features of claim 1.
According to the invention there is a separate contact element that forms the electrical connection between the casing and the shielding when the subassemblies of the plug or socket are put together. Such a separate contact element is part of one of the subassemblies and can either be fitted over the shield braid of the cable after the shield braid has been exposed. The thus trimmed end of the cable is then put together with the remaining subassemblies in order to hook up the plug or socket and complete it. This is done in one step without having to deal further with the shield braid (for example it is not necessary to spread it as in the prior art) in order to make the shielding continuous. Or the contact element is put into one of the subassemblies of the plug or socket and then the cable with the exposed shield is set in place. In a particularly advantageous embodiment of the invention the contact element is formed as an iris spring whose shape allows it to bear radially inward on the exposed shield braid and radially outward on the casing to form a good electrical connection between the shield braid and the casing. An iris spring has the further advantage that it is at least limitedly elastically compressible so as to be able to compensate out tolerance problems and bring to bear the necessary spring force for a good connection over the service life of the plug or socket.
In addition to cables that have a plurality of conductors surrounded by a shield braid, there are shielded cables in which there is at least one shield or ground conductor. Such cables, that if necessary have both a shield/ground wire and a shield braid are used in networks for certain bus systems. Here also there must be a continuous shielding of the cable over the plug connection (e.g. from a plug to a socket or from a plug or a socket to a sensor, an actuator, a device or the like) at high data rates or high frequency. According to the invention this is accomplished in that the shielding inludes one or more wire conductors and the electrical connection between a housing part of the plug or socket and a contact is effected through a contact element. In this manner a standard press-fit terminal is used to connect up the wire conductor for the shield and also to form a connection between this contact and the casing of the plug or sleeve for outside shielding.
A particular advantage of the plug or sleeve for press-fit application is when the individual contacts are symmetrically arranged, since this makes it possible to carry high data rates or high frequencies. An example for such a symmetrical is a five-pole plug where there is a central contact and a plurality of outer contacts surrounding it (four or at least four such outer contacts). To this end according to a further feature of the invention that is described in the dependent claims the contacts have particular shapes and orientations so as to make the plug (or socket) particularly compact. Only with such orientation and arrangement of the press-fit terminals of the contacts and the orientation of the terminals in the contact holder and wire holder is it possible to provide a central contact.
Therein:
a,
1
b, and 1c are overall, sectional, and detail views of a first embodiment of a plug;
a and 4b are various views of a wire holder for receiving the ends of the conductors and the press-fit terminals in the region in which the press-fit contacting takes place;
FIGS. 9 to 11 are overall, sectional, and detail views of a further embodiment of a plug.
The embodiment relates to a five-pole standard industry (IP 67 according to IEC 60529) E-series plug of a connector according to IEC 61076-2-101 with quick-connect press-fit terminals and axial cable feed in a particularly compact construction. The plug is assembled by the user without the use of tools. It is not necessary to clamp or strip the wires before insertion into the press-fit terminals. In addition the plug can be supplied in a shielded style with electrically throughgoing metallic or metallized housing parts where the cable shield, when used as a quick connect, can be particularly simply and quickly electrically connected to the casing. The plug of such a connection is used with a socket for example to transmit ethernet signals, that is at data rates of 100 Mbps. Furthermore for example the central conductor can be connected with the metallic casing.
a shows the subassemblies that make up the plug partly individually and partly in exploded view:
Entire contact holder: Contacts 1 and contact holder 2 and coupling element 3 and contact element 4 and coupling element 620 and seal element 5 and contact element 13.
Wire holder 7;
Entire casing (grip sleeve): Sleeve 9 and contact element 8; alternatively the sleeve 9 and the contact element 8 can be provided as individual parts.
Entire strain-relief element: Seal element 10 (for example a hose or O-ring) and strain-relief element 11.
Actuating element 12. The actuating element 12 serves to press the strain-relief element 11 and the seal element 10 against and lift it from the surface of the cable and is shown in
The subassemblies and their element and their shapes are described in the following with if necessary reference to other figures.
The plug shown in
The electrical contact 1 (see also
In addition the plug has a coupling element, in particularly the closed metallized or metallic coupling element 3 with a knurled surface that is shown in
a and 4b show various views and sections of a wire holder 7 of electrically insulating material and formed with wire seats 7.1 in which the respective wires are held and positioned for contacting with the respective press-fit clips. The wire seats 7.1 are formed as funnels at one end with wire-guiding entry bevels or roundings 7.7. Further in (direction -z) the shape of the seats 7.1 is at first of uniform cross-section with the area m* n (see
The deflecting ribs 7.2 or the deflecting rib 7.3 have toward the abutment 7.6 a further flank 7.3.2 that also centers the end of the conductor, above all during backward deflection during deflection into the press-fit clip with respect to the actual shape of these flanks 7.3.2 the same is true as for the flanks 7.2.2 and 7.3.3. The abutment 7.1, the deflecting flank 7.4, and the deflecting ribs 7.2 and 7.3 are so spaced along the z-axis that it is possible to push the conductor into the wire seat 7.1 with a relatively small force. A further important part of the wire seat 7.1 is the guide surface 7.5 which serves to guide the press-fit arms 1.4 and above all to resist their elastic outward deflection when a conductor is fitted in. The deflection of the guide surface 7.5 in the z-direction is at least as long as the insertion depth of the pressfit clips and ends preferably at the lower flank of the deflecting rib 7.2. Since the deflecting rib 7.3 is located about halfway along the insertion depth, it is sure that the conductor will be engaged at least once and often at two location offset in the z-direction so as to make a very good connection. Like the guide face 7.5, the wire holder 7 has openings 7.5.1 open toward the press-fit clips so that the press-fit clips can engage into the respective wire seats 7.1. The outer shape of these openings 7.5.1 conforms either over its entire circumference or only over a part thereof (for example when the press-fit arms 1.4 are supported or guided at specific location) to the outer shape of the respective press-fit clip while the remaining region is spaced from the press-fit clip. It is important in this regard that the wire holder 7 is made by injection molding so that the x-y projection of the inner shape of the opening 7.5.1 facilitates demolding with the projection of the seat surface 7.4.1 that extends over the deflecting race 7.4 to the deflecting rib 7.2. On the other hand this inner shape corresponds with the lower edge 7.2.3 of the deflecting rib 7.2. The opening 7.5.1 is provided with the entry bevel 7.5.2 that prevents canting of the entering press-fit clip. On the side of the wire holder 7 toward the press-fit clips it has at each wire seat 7.1 further openings 7.3 whose number corresponds to the number of deflecting ribs 7.3 with the particular feature that their shape is larger to allow demolding long the x-y projection of the deflecting ribs 7.3. It is important in any case that the openings 7.3 not be too big so that the smallest possible conductor can be slid through them or the abutment 7.5 would become ineffective. If one is certain that the x-y projection of the deflecting ribs 7.2 and 7,3 and the deflecting flank 7.4 of the abutment 7.6 do not overlap, the wire seats 7.1 or the entire wire holder can be deformed in a very simple manner along the longitudinal axis z. Further features of the wire holder are the coding or twist preventer 7.9, the guide face 7.16, and the abutment face 7.15 that are important with regard to the contact holder 2. The groove 7.11 serves for holding or guiding the contact element 13. The groove-like recess 7.11 also forms a coding or twist preventer for the sleeve 9. The surfaces 7.12 are grip surfaces by means of which the wire holder 7 can be pulled out of the contact holder 2. The wire holder 2 is engaged on the faces 7.13 indirectly via the sleeve 9 and the coupling element 6 with the contact holder carrying the press-fit clips. The test bore 7.14 that extends conically over a portion of its length allows the user to determine if the diameter of the wire to be fitted will go into the wire seat 7.1 of the wire holder 7. The conical (or alternately flat) surface 7.17 has the function of fixing the contact element 8 in the z-direction such that a radial force component is created toward the plug center axis, that is toward the cable shielding.
The contact element 8 serves to electrically connect the shielding of the cable and the casing of the plug (here the sleeve 9) in order to effect throughgoing shielding. The iris spring is particular advantageous because it can be slipped without other means or special fitting over the shielding of the cable.
Like the abutment faces 7.13 on the wire holder 7, the sleeve 9 has engagement faces 9.6. The conical (or alternatively even flat) surface 9.7 has for the contact element 8 the same function as the surface 7.17 of the wire holder 7.
For assembly (connecting the cable according to press-fit techniques and putting together of the plug) there are the following subassemblies and individual parts:
a and 9b as well as 10 and 11 are overall, sectional, and detail views of a further embodiment of a plug. The plug shown in these figures is different from that of
| Number | Date | Country | Kind |
|---|---|---|---|
| 103 02 711.4 | Jan 2003 | DE | national |
| 103 23 614.7 | Mar 2003 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP03/14157 | 12/12/2003 | WO | 3/30/2006 |