1. Field of the Invention
In invention relates to a cable terminal or joint means as disclosed in commonly owned, related patent application DE 199 51 455, which has been filed as U.S. patent application Ser. No. 09/695,415, and is drawn to a cable terminal or joint means for making an electrically conductive connection. The invention relates to a cable terminal or joint means for making an electrically conductive connection between a cable and an electrical device, or for making an electrically conductive connection between two cables. When connecting one cable to an electrical device, the connection is a cable terminal means; while, if two cables are to be connected to one another, the connection is a cable joint means. When the invention is a cable terminal means, the invention includes a cable terminal component and a device terminal component. Further, when the invention is a cable joint means, the electrically conductive connection includes a first cable joint component and a second cable joint component. In the discussion of the invention to follow, most of the focus is on a cable terminal means, but nevertheless a cable joint means is always intended as well.
2. Description of Related Art
In the related German patent application DE 199 51 455, and corresponding U.S. patent application Ser. No. 09/695,415, the electrically conductive connection can be between a multi-core cable and an electrical device, or between two multi-core cables with one cable terminal component and with a device terminal component, or between a first cable joint component and second cable joint component. The electrically conductive connection can also be made between a cable terminal component and a first cable joint component, a device terminal component, or a second cable joint component. The cable terminal or joint means includes a union nut, a wire receiving and guide part which has a plurality of wire guide channels, a clamping and terminal unit which is provided with insulation piercing connecting devices and with terminal elements, and a sleeve-like terminal body or connecting body which is provided with an outside thread which corresponds to the inside thread of the union nut. The wire ends make contact with the insulation piercing connecting devices and are squeezed by the insulation piercing connecting devices, each running at an angle less than 180xc2x0, thereby cutting through the wire insulation of the wire ends and making contact with the conductors when the union nut is screwed onto either the terminal body or the connecting body, or when the terminal body or the connecting body is screwed into the union nut.
In the discussion to follow, it is also noted that reference to a cable terminal means is intended to relate to a means for making an electrically conductive connection between a cable and an electrical device; where an electrical device should be understood quite generally, and in particular, the expression electrical device includes electrical components, means and devices.
It is further noted that for the cable terminal or joint means discussion to follow, the cable terminal component and the first cable joint component, the device terminal component, or the second cable joint component includes the following
a union nut,
a wire receiving and guide part,
a clamping and terminal unit which is provided with insulation piercing connecting devices and with terminal elements and
a sleeve-shaped terminal or connection body which is provided with an outside thread which corresponds to the inside thread of the union nut.
Thus, it is intentionally left open which of the individual parts, for example, the union nut, the wire receiving and guide part, the clamping and terminal unit, or the terminal or connecting body relate to the cable terminal component, the first cable joint component, the device terminal component, or the second cable joint component. However, it can be generally understood that:
that the union nut generally relates to the cable terminal component or the first cable joint component,
that the wire receiving and guide part relates to the cable terminal component or the first cable joint component,
that the clamping and terminal unit relates to the device terminal component or the second cable joint component and
that the terminal or connection body generally relates to the device terminal component and the second cable joint component.
It is also noted that the wire ends and the insulation piercing connecting devices run at an angle of less than 180xc2x0 to each other which means that the wire ends and the insulation piercing connecting devices do not run parallel to one another, because to do so would mean the insulation piercing connecting devices cannot act on the wire ends in the proper manner. The angle between the wire ends and the insulation piercing connecting devices can be both an acute and also a right angle; however, an obtuse angle is also not precluded. Accordingly, the wire guide channels which hold the wire ends and which are provided in the wire receiving and guide part are angled relative to the insertion direction of the cable. In order to ensure simple deflection of the wire ends during insertion that angle should be less than 90xc2x0.
Finally, it is noted that when the union nut is screwed onto the terminal or connecting body or when the terminal or connecting body is screwed into the union nut, the insulation piercing connecting devices cut the wire insulation of the wire ends and make contact with the conductors. Screwing the union nut onto the terminal or connecting body or screwing the terminal or connecting body into the union nut leads to relative motion between the wire receiving and guide part and the clamping and terminal units and thus leads to relative motion between the wire ends and the insulation piercing connecting devices. This relative motion leads to the insulation piercing connecting devices cutting through the wire insulation of the wire ends and then making contact with the conductors.
For better understanding, the cable terminal or joint means discussed below is limited to a cable terminal means, with the referred to individual components being the cable terminal component on the one hand and the device terminal component on the other hand.
Therefore, the discussion specifically refers to a cable terminal means for making an electrically conductive connection, which includes one cable terminal component and one device terminal component, of preferably a multi-core cable to an electrical device. The cable terminal component includes a union nut and a wire receiving and guide part; while the device terminal component includes a clamping and terminal unit which is provided with insulation piercing connecting devices and with terminal components, and a sleeve-shaped outside terminal body which is provided with an outside thread which corresponds to the inside thread of the union nut. When the terminal components are being assembled, the wire ends, running at an angle of less than 180xc2x0 to the insulation piercing connection devices, are squeezed by the insulation piercing connecting devices to pierce the insulation on the wire ends and make electrical connection with the conductors. This occurs when the union nut is screwed onto the terminal body, that is, the insulation piercing connecting devices cut through the wire insulation of the wire ends and making contact with the conductors.
The aforementioned individual parts, that is, the wire receiving and guide part, the clamping and terminal unit, and the terminal or connecting body will now be explained. The following explanation of these individual parts relates to the above addressed cable terminal means in which the terminal or connecting body is called only the terminal body.
The wire receiving and guide part which belongs to the cable terminal component is conventionally provided on the cable side with a single receiving or insertion opening for the receiving all of the wires, or is conventionally provided with a number of receiving or insertion openings which corresponds to the number of individual wires. Moreover, the wire receiving and guide part on the cable side is provided with wire guide channels. If the wire receiving and guide part on the cable side has only one receiving or insertion opening, this receiving or insertion opening then branches into the individual wire guide channels. If, however, on the cable side a number of receiving or insertion openings corresponding to the number of wires to be inserted is utilized, then the individual receiving or insertion openings pass into the wire guide channels.
The wire guide channels, which are within the wire receiving and guide part, are configured and guided taking into consideration the geometry and the arrangement of the insulation piercing connecting devices in the clamping and terminal unit such that the wire ends, to be squeezed by the insulation piercing connecting devices and make contact with the insulation piercing connecting devices, run at the desired angle, for example at an acute angle or at a right angle.
The clamping and terminal unit associated with the device terminal component is provided on the side facing the wire receiving and guide part with insulation piercing connecting devices, and on the other side with terminal components. The insulation piercing connecting devices and the terminal components are metal parts which are generally constructed in one piece having on one end the insulation piercing connecting devices and on the other end the terminal elements. The execution and configuration of the terminal components depends on which type of connection is desired or available for the internal wiring of the corresponding electrical device. In particular, the terminal components can be made as flat connector, wire wrap, or as solder terminal components.
In the cable terminal means under discussion herein, the union nut and the wire receiving and guide part represent the two important functioning elements of the cable terminal component, while the sleeve-shaped terminal body and the clamping and terminal unit represent the two important functional components of the device terminal component. When screwed together, i.e., when the union nut is screwed onto the terminal body, the union nut and the terminal body form a closed housing which holds and surrounds the inner function elements, specifically the wire receiving and guide part and the clamping and terminal unit.
In the known cable terminal or joint means, the union nut and the wire receiving and guide part are two individual parts which are not connected to one another. Nor is a connection allowable because when the union nut is screwed onto the terminal or connecting body the wire receiving and guide part may not turn or cannot turn. This connection has the consequence that when the terminal or connection is unscrewed again, i.e., unscrewing the union nut from the terminal or connecting body, the cable remains connected or joined because the insulation piercing connecting devices of the clamping and terminal unit are still xe2x80x9cfixingxe2x80x9d the clamped conductors. Therefore, to disassemble the terminal or the connection after unscrewing the union nut from the terminal or connecting body additional loosening of the conductors held by the insulation piercing connecting devices is required.
The aforementioned problem is essentially solved in the cable terminal or joint means as set forth in related German patent application DE 199 51 455, and corresponding U.S. patent application Ser. No. 09/695,415, in that the wire receiving and guide part is axially fixed via at least one slotted, elastic locking ring in the union nut and that the wire receiving and guide part can be turned in the axially fixed position relative to the union nut.
This has the major advantage that the relative axial motion between the union nut and the terminal or connecting body which accompanies the unscrewing of the union nut from the terminal or connecting body is also the relative axial motion between the wire receiving and guide part and the terminal or connecting body. This relative motion necessarily leads to the conductors, which were clamped by the insulation piercing connecting device, coming free from the insulation piercing connecting devices. If in the cable terminal or joint means as set forth in the noted related patent applications, and as also accomplished in the prior art, the clamping and terminal unit is fixed in the terminal or connecting body, as set forth in the mentioned related patent applications, then there is a cable terminal or joint means which is formed functionally of only two components, specifically the cable terminal component or the first cable joint component on the one hand and the device terminal component or the second cable joint component on the other.
The elastic locking ring is held in the unassembled state on the wire receiving and guide part and the union nut, preferably on the wire receiving and guide part. To do this, the wire receiving and guide part is provided with several axial holding projections which are each provided on the end side with feed bevels to allow the locking ring to be slipped on more easily.
This embodiment however, entails the risk that the locking ring can be lost before installation of the cable terminal means, i.e., before the union nut is screwed onto the terminal body. This can also happen when the cable terminal means is installed, i.e., when the union nut is screwed onto the terminal body and the locking ring is pushed by the wire receiving and guide part.
The instant invention provides a solution to the problem set forth in regard to the related German patent application DE 199 51 455, and corresponding U.S. patent application Ser. No. 09/695,415, by preventing unintentional loosening of the locking ring from the wire receiving and guide part.
This object is achieved in the cable terminal or joint means of the instant invention when the locking ring is made in one piece with the wire receiving and guide part. Because the locking ring is no longer made as a separate component, on the one hand, one installation step, specifically slipping the locking ring onto the wire receiving and guide part, is eliminated; while, on the other hand, the possible loss of the locking ring is prevented.
Essentially for the cable terminal or joint means as set forth in related patent applications DE 199 51 455 and 09/695,415 there are two possibilities for the sequence in which the cable can be connected to the cable terminal component or to the first cable joint component. In the first possibility, first the wire receiving and guide part can be axially fixed in the union nut and then the multi-core cable with the individual wires can be inserted through the union nut and the receiving and insertion opening into the wire receiving and guide part. In this first instance, the insertion of the individual wires into the wire guide channels of the wire receiving and guide part is made more difficult by the wire receiving and guide part being at I cast partially covered by the union nut. That is, the receiving and insertion opening is located within the union nut and is thus somewhat more difficult to access. In the second possibility, first the multi-core cable can be connected to the wire receiving and guide part, i.e., the cable is pushed through the receiving and insertion opening and the individual wires are inserted into the wire guide channels. Only then are the wire receiving and guide part and the union nut joined. Here, the insertion of the cable and the individual wires is indeed simpler, but the danger is greater that the elastic locking ring will be lost before joining the wire receiving and guide part and the union nut. This circumstance is prevented when the wire receiving and guide part and the locking ring are made in one-piece of the instant invention.
For the one-piece fabrication of the locking ring with the wire receiving and guide part however the following must be watched. When the wire receiving and guide part and the union nut are joined together, the locking ring which in its cross section is not larger than the diameter of the inside thread of the union nut must be turned through the inside thread of the union nut to its end. In doing so, the locking ring according to the thread pitch of the union nut assumes an axial slant. If the locking ring is made in one piece with the wire receiving and guide part, the slant of the locking ring first leads to the wire receiving and guide part assuming an axial slant. It has now been recognized as part of the instant invention that the slightly slanted position of the wire receiving and guide part can be tolerated when the union nut is screwed on. However, it is advantageous if the locking ring has a certain mobility relative to the wire receiving and guide part in spite of its being made in one piece with the wire receiving and guide part.
This is achieved according to one preferred embodiment of the invention when the locking ring is connected to the wire receiving and guide part via retaining bars. If the locking ring is connected only via the retaining bars and not over the entire periphery of the wire receiving and guide part to the latter, as a result of the elastic properties of the locking ring and due to the fact that the locking ring is a slotted locking ring, a certain mobility of the locking ring arises relative to the wire receiving and guide part. Thus, the locking ring can assume an axial slant according to the thread pitch while the wire receiving and guide part experiences only a much smaller slant or none at all.
In addition to attaching the locking ring with the wire receiving and guide part via retaining bars it is also possible to connect the locking ring to the wire receiving and guide part via a film hinge or a thin membrane. The film hinge or the thin membrane also ensures a certain mobility of the locking ring relative to the wire receiving and guide part. Of course, it is also possible to connect the locking ring to the wire receiving and guide part both via one or more retaining bars and also via a film hinge or a thin membrane.
In particular, there are a host of possibilities for embodying and developing the cable terminal or joint means of the invention as can be envisioned from the following discussion of the invention.