Abstract:
An electrical connection element for connecting an electrically insulated end of a wire has a clamping sleeve in which an end of a wire is insertable and clampable, an insulation sleeve connectable with the clamping sleeve and provided with a connecting contact arranged so that, during a connection of the clamping sleeve with the insulation sleeve the connecting contact of the insulation sleeve is brought into contact with an end of a wire with removal of an insulation of the wire, and is then held there.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to an electrical connecting element.  
           [0002]    More particularly it relates to an electrical connecting element which can be connected to an electrically insulated end of a wire, wherein the end of the wire during connection of the connecting element is simultaneously bared and reliably mounted in the connecting element.  
           [0003]    For connections of connecting elements, such as bushing or electrical plugs, to an electrical wire, conventionally the end of the wire is bared and then connected by means of a clamping or screw connection with a connecting element. There are however applications in which during the process of connection of a connecting element to a wire, the wire to be bared must not be contacted. This is the case for example in the medical field, when for example an external heart pacemaker must be connected to the conductors which are connected with the heart muscles and extend out of the body. In this case the conductors which extend out of the body must not be contacted with its conductive core. A contact of the conductive core of the wire can cause an electrical discharge. Such an electrical discharge can lead to grave heart rhythm distortions up to a heart chamber flicker. In this particular case the connecting element must be connected to the slotted and further electrically insulated end of the wire without removing the insulation of the wire.  
           [0004]    So-called clamping plugs are known in the prior art in particular from the company Multi-Contact AG, Basel, Switzerland. In these clamping plugs the insulated wire is clamped in a plug and simultaneously the insulation is removed. These plugs are however relatively expensive, susceptible to failures, voluminous and difficult to operate, since they contain a spring element and a pressure button. Moreover, diverse plug elements for bared wires are known as well.  
         SUMMARY OF THE INVENTION  
         [0005]    Accordingly, it is an object of the present invention to provide an electrical connecting element for connection to an electrically insulated end of a wire, which avoids the disadvantages of the prior art.  
           [0006]    More particularly, it is an object of present invention to provide an electrical connecting element for connection to an electrically insulated end of a wire, in which the wire before the connection must not be bared, which is easy to handle, and which has a small size and a simple construction.  
           [0007]    In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in an electrical connecting element having a clamping sleeve in which an end of the wire is insertable and clampable, and an insulation sleeve connected to the clamping sleeve and provided with a connecting contact, so that during connection of the clamping sleeve and the insulation sleeve, the connecting contact of the insulation sleeve is brought in contact with the end of the wire with maintaining of the insulation of the wire, and is held in this position.  
           [0008]    When the electrical connecting element is designed in accordance with the present invention, it eliminates the disadvantages of the prior art and provides for the above mentioned advantages. The inventive electrical connecting element is composed of two parts including a so-called clamping sleeve and a so-called insulation sleeve which are connectable with one another. The electrically insulated end of the wire, to which the electrical connecting element must be connective, is first inserted in the clamping sleeve and then preliminarily clamped. For this purpose it can be inserted in a correspondingly formed passage of the clamping sleeve and firmly clamped there. Preferably, this passage is formed so that the end of the wire is inserted in a doubled force unloading loop and held in it.  
           [0009]    The clamping sleeve and the insulation sleeve are formed so that, when they are connected with one another for example by screwing, the wire is clamped between them and its insulation eliminated, and a connection contact which is provided in the insulation sleeve is brought in electrical contact with the bared end of the wire.  
           [0010]    For providing this clamping and simultaneous insulation removal of the wire end, the clamping sleeve has for example a recess with a diameter which expands toward the connection point. The recess is formed for example as a funnel. The end of the wire is inserted into the clamping sleeve preferably so far that the end of the wire is located substantially at the connecting point between the clamping sleeve and the insulation sleeve. The connecting contact of the insulation sleeve includes a forwardly reducing squeezing contact element, which is formed so that during connection of the clamping sleeve and the insulation sleeve it is forced into the recess of the clamping sleeve. Thereby the end of the wire located there is squeezed against the wall of the recess of the clamping sleeve.  
           [0011]    The squeezing contact element can be formed in different ways with consideration of the above described deformation. It can be formed for example from the screw thread, from several disks arranged at a distance from one another and having a reducing diameter, or from several cylinders with a reducing diameter. It is important that during insertion of the squeezing contact element the end of the wire is not upset, but instead is reliably pressed against the wall of the recess of the clamping sleeve, and simultaneously the insulation is removed from the wire end. The outer edges of the squeezing contact element must be formed so sharp that they can remove the insulation of the wire end, but at the same time must not be too sharp that they can cut the wire strand. A further securing against separating of the wire strand is provided by a certain yieldability of the clamping sleeve material.  
           [0012]    The connecting contact of the insulation sleeve, in addition to the squeezing contact element also advantageously has a connecting member which is electrically connected with the squeezing contact element. The connecting member can be formed for example as a plug pin or a plug bushing. A correspondingly shaped plug bushing or a plug pin can be connected with the thusly formed connecting member so that an electrical conductor and an electrical wire are connectable with the inventive connecting element. The plug pin or the plug bushing must be insulated from outside, so as to prevent the users contact with the bared wire.  
           [0013]    The clamping sleeve and the insulation sleeve can be connected with one another in a known manner. For example they can be provided for this purpose with matching screw threads or a connection device in form of bajonet lock or a louver lock connector.  
           [0014]    The clamping sleeve and the insulation sleeve must be composed of an electrically insulating material. For this purpose for example an impact-resistant plastic which is not flowable at the corresponding application temperatures can be utilized. For the use in the medical field it is advantageous when a synthetic plastic or a similar material is selected so that, it can be easily sterilized for example in ethylenoxide. For preventing erosion in unfavorable application conditions and nevertheless maintaining a good electrical contact, it is advantageous when the electrically conductive parts, such as for example the connection contact of the insulation sleeve, are composed of non-corroding materials, for example high grade steel. Moreover, these materials can be coated, for example brass gilded, for improving the electrical contact.  
           [0015]    In accordance with a further preferable embodiment of the present invention, in an electrical connecting element the clamping sleeve and the insulation sleeve can be secured by an arresting clamping from an inadvertent loosening, for example by screwing. The clamping sleeve can be provided with a projection near the outer thread on its outer side, which is insertable into a gap of the periphery of the arresting clamping ring, to produce an arresting connection between the clamping sleeve and the arresting clamping ring.  
           [0016]    In accordance with a further preferable embodiment of the present invention, the arresting clamping ring during screwing of the clamping sleeve and the insulation sleeve with one another can overcome the projection by deformation when an arresting torque is exceeded. The projection is dimensioned so that during a further screwing of the both sleeves, it vanishes in the inner thread of the insulation sleeve and has no more alternating action with the arresting ring. The sleeves can be screwed without further resistance and the inserted wire is squeezed.  
           [0017]    The insulation sleeve can be provided on its outer side with a peripheral bead and with at least one axially oriented web which forms an abutment for at least one arresting hook arranged on the inner side of the arresting clamping ring, when the clamping sleeve with the arresting clamping ring arrested with it is inserted into the insulation sleeve. The at least one arresting hook is non-releasably arrested over the peripheral bead and thereby prevents an unscrewing of the clamping sleeve and the insulation sleeve.  
           [0018]    After mounting of the clamping sleeve and the insulation sleeve, the arresting clamping ring is used so that the insulation sleeve and the clamping sleeve no longer can turn relative to one another and therefore again release from one another. Preferably, the insulation sleeve have four axially oriented webs which form abutments for the four arresting hooks arranged on the clamping ring. Thereby it can be guaranteed that practically no rotary movement of the insulation sleeve relative to the clamping sleeve is possible.  
           [0019]    The inventive electrical connecting element is easy to operate, it has a simple construction. It is small, it can be reliably mounted on a not insulated wire, and the user does not come into contact with the electrically conductive part of the wire, so that the inventive electrical connecting element is especially advantageous for use in the medical field, for example for connection of an external heart pace maker.  
           [0020]    The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.  
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0021]    [0021]FIG. 1 is a schematic exploded view of a cross-section of an electrical connecting element in accordance with the present invention;  
         [0022]    [0022]FIG. 2 is a view showing the inventive connection element of FIG. 1 in an assembled condition;  
         [0023]    [0023]FIG. 3 is a view showing another embodiment of a connecting contact of an insulation sleeve of the inventive connection element;  
         [0024]    [0024]FIG. 4 is a view showing still a further embodiment of the connecting contact of the insulation sleeve of the inventive connection element;  
         [0025]    [0025]FIG. 5 is a view showing an example of the application of the inventive electrical connection element for connection of a heart pacemaker;  
         [0026]    [0026]FIG. 6 is a perspective exploded view of a further embodiment of a connection element;  
         [0027]    [0027]FIG. 7 is a view showing a longitudinal section of the connection element of FIG. 6 in a screwed-on condition and during insertion of a wire; and  
         [0028]    [0028]FIG. 8 is a view showing a longitudinal section through the connection element of FIG. 6 in the screwed-on condition after the mounting on the wire.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0029]    [0029]FIG. 1 shows schematically a cross-section of an inventive electrical connection element. For clear understanding of the individual elements of the connection element, they are shown on an exploded view. The electrical connection element in accordance with the present invention includes two parts, namely a clamping sleeve  10  and an insulation sleeve  20 . An end of a wire  30  which must be connected to the connection element is inserted in the clamping sleeve. For this purpose the clamping sleeve  10  has an opening in which the wire  30  can be inserted. In the shown embodiment the opening is composed of a passage  12  and a funnel-shaped inlet  14 , via which the wire  30  formed as a force unloading loop can be inserted. The clamping sleeve  10  has an expanding opening  16  at its end which faces the insulation sleeve  20 . It is funnel-shaped also. The wire  30  later is firmly clamped in the opening  16 . The wire  30  for this purpose must be inserted into the clamping sleeve  10  so that its end ends substantially at the end of the recess  16 .  
         [0030]    A squeezing contact element  20  of a connection contact  21  of the insulation sleeve  20  engages in the recess  16  of the clamping sleeve  10  when the clamping sleeve  10  and the insulation sleeve  20  are connected with one another. It clamps the end of the wire  30 , as can be seen better from FIG. 2. The squeezing contact element  32  for this purpose has a shape with a forwardly reduced diameter, which is provided with edges. The squeezing contact element  22  in the shown embodiment is formed as a screw.  
         [0031]    The connecting contact  21  of the insulation sleeve  20  additionally has a connection member  23  which is electrically connected with the squeezing contact element. The connection member  23  is formed here as a plug pin. A not shown plug bushing can be connected with the plug pin so as to connect the inventive connection element with further electrical wires, which can be used for example for connection of an external heart pacemaker. For preventing contact of the user with the electrical wire, the connection member  23  is preferably insulated from outside. The plug pin which serves here as the connection member  23  is simply guided in an outer sleeve  24 .  
         [0032]    The clamping sleeve  10  and the insulation sleeve  20  must be connected with one another. For this purpose the clamping sleeve  10  is provided with an outer thread  18 , while the insulation sleeve  20  is provided with an inner thread  25 , so that the both sleeves can be screwed with one another. Naturally other connections are also possible, such as for example a bajonet lock or an arresting connection.  
         [0033]    [0033]FIG. 2 schematically shows a cross-section of the connection element of the present invention shown in FIG. 1, in an assembled condition. The clamping sleeve  10  and the insulation sleeve  20  are here screwed with one another and thereby connected with one another. It can be seen that the end of the wire  30  is squeezed between the squeezing contact element  22  and the wall of the recess  16 . The edges of the squeezing contact element  22  here the outer edges of the screw, displace simultaneously the insulation of the wire  30 , so that an electrical contact between the wire  30  and the squeezing contact element  22  is produced, and the electrical wire  30  simultaneous is firmly held between the squeezing contact element  22  and the wall of the recess  16 . At the right end of the insulation sleeve  20 , it can be seen that the connection member  23  which is formed as a plug pin is located in its sleeve  24 .  
         [0034]    [0034]FIG. 3 shows another embodiment of the connecting contact  21  of the insulation sleeve  20 . The squeezing contact element  22  of the connecting contact  21  is composed here of several disks  26  which are arranged at distances from one another. They have a diameter which reduces forwardly.  
         [0035]    [0035]FIG. 4 shows still a further embodiment of the connecting contact  21  of the insulation  20 . The squeezing contact element  22  of the connecting contact is composed of several cylinders  27  which are arranged one behind the other. The diameters of the cylinders  27  also reduce forwardly.  
         [0036]    [0036]FIG. 5 finally shows the use of the inventive connection element for connection of an external heart pacemaker  40  to a heart wire, or in other words a wire  50  which is connected with the heart muscle  52  and extends outwardly beyond the body. The wire  50  is formed as a lead pair. The external heart pacemaker  40  has two connecting conductors  42  which are provided at their ends with plugs  44 . The plugs are connected correspondingly with the connecting conductors  42  of both electrical connection elements  64  formed in accordance with the present invention. The upper inventive connection element  60  is shown in a disconnected position and a lower inventive connection element  60  is shown in the connected position.  
         [0037]    [0037]FIG. 6 shows the details of a further connection element in accordance with the present invention. All parts, with the exception of the connecting contact  22 , are composed of a synthetic plastic, for example transparent heart PVC, PC or ABS. Alternatively to the sleeve  24  of FIG. 4, here a contact protective cap  80  is provided for the connecting contact  21 . For avoiding its loss it is connected via a connecting web  82  with a holding ring  81 . For improved frictional clamping on the connecting contact  21 , the contact protective cap  80  is composed of a soft material, such as for example PE or PP. When the connection element is used for connection to an external heart pacemaker, the protective cap  80  for marking the implantation position of a pacemaker electrode  30  can be colored to be recognized by the user. The holding ring  81  is displaced into the parts  10  over the outer surface of the funnel-shaped recess  16  for safety reasons. A projection  19  formed as a raised cylinder sector before the outer thread  18  is also provided on this outer surface. The height of the projection  19  is dimensioned so that, it corresponds to the radial thread gap between the outer thread  18  and the inner thread  25  shown in FIG. 7. Thereby the later screwing mounting is not negatively affected. The peripheral width of the projection  19  corresponds to the width of the gap  72  of an arresting clamping ring  70  for securing the parts  10  and  20 .  
         [0038]    In order to assemble the connection element shown in FIGS. 7 and 8, first the clamping ring  70  is clipped on the outer surface of the recess  16 . The projection  19  must be located in the gap  72 . After the insertion of the connecting contact  21  into the insulation sleeve  20 , the outer thread  18  is screwed into the first thread turn of the inner thread  25 . Thereby the arresting hook  71  of the arresting clamping ring  70  engages over a peripheral bead  32  of the insulation sleeve  20 . It can be located between axial webs  28  on the outer surface of the sleeve  20 . The arresting clamping ring  70  prevents in this way an inadvertent unscrewing of the parts  10  and  22 . The axial web  28  prevents via the arresting hook  71  a turning of the arresting clamping ring  70 . After the displacement of the contact protective cap  80  on the connecting contact  21 , the connection element is in condition ready to use, as shown in FIG. 7.  
         [0039]    [0039]FIG. 7 also shows how a user displaces a wire, for example the extracarporeal end of an implanted heart pacemaker electrode  30 , through the funnel-shaped inlet  14  on an insertion cone  29  of the connecting contact  21  along an insertion path  31 . The projection  19  of the part  10  is urged in the gap  72  of the arresting clamping ring  70  as shown in FIG. 6 because of the and provides the rotation safety of the arresting clamping ring  70  for an easy screwing safety of the total configuration of the connecting plug. With this screwing safety it is guaranteed that the user after unpacking of the element always holds the connection element in its hands in screwed-on, assembled, mounting-ready condition. After the insertion of the wire  30  or the heart pacemaker electrode, with a force screwing of the both parts  10  and  20 , the fixation by the projection  19  and the gap  72  is overcome, and finally the wire  30  is clamped and bared between the funnel-shaped recess  16  and the squeezing contact element  22  as shown in FIG. 6.  
         [0040]    [0040]FIG. 8 shows the connected, operation-ready connection element. Before the insertion in a temporary heart pacemaker machine shown in FIG. 5, the contact protective cap  80  must be withdrawn from the connecting contact  21 . In the embodiment of a connection element with a fixed sleeve  24  for contact projection shown in FIG. 1 and the available corresponding safety bushings on the temporary heart pacemaker, the contact protective cap  80  can be dispensed with.  
         [0041]    It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.  
         [0042]    While the invention has been illustrated and described as embodied in electrical connecting element, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.  
         [0043]    Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.