IE61331B1

IE61331B1 - Terminal block for connecting each of a plurality of incoming insulated conductors to each of a plurality of departing insulated conductors

Info

Publication number: IE61331B1
Application number: IE191388A
Authority: IE
Inventors: Leif Birger Hoeglund; Rolf Bertil Hemstroem; Alf Thomas Westerlund; Kurt Anders Sigfrid Hamrin
Original assignee: Ericsson Telefon Ab L M
Priority date: 1987-07-03
Filing date: 1988-06-23
Publication date: 1994-11-02
Also published as: DK101789A; SE8702766L; DE3890562C2; SE8702766D0; NO890642L; DK101789D0; GB8902570D0; FI93593C; FI890780A0; DK170011B1; NO890642D0; GB2215532A; SE458066B; NO175127C; FI890780A; NO175127B; WO1989000345A1; FI93593B; IE881913L; GB2215532B

Abstract

The invention relates to a terminal block formed for electrically connecting each of a plurality of incoming insulated electrical conductors with each of a plurality of departing insulated electrical conductors. The terminal block includes a contact element holder of insulating plastics in two parts (1, 2) and a plurality of contact elements in the contact element holder. The contact elements are of a first type (18) or a second type (26) and formed for coaction in pairs. Each contact element includes a slotted part (22, 27) formed for penetrating the insulation of and making contact with the conductor when an insulated conductor (16, 17) is inserted in the slot. Each first type contact furthermore includes a leg (20) with cutting edge (24) while each second type contact element includes a sprung part (28). The sprung part is formed such as to be taken by spring bias into engagement against the leg with sharp edge. For each pair of coacting contact element the terminal block also includes a part (35) with a cutting edge (36) situated at a distance from and between the leg with a cutting edge and the slotted part (27) of the second type contact element (26).

Description

TERMINAL BLOCK FOR CONNECTING EACH OF A PLURALITY OF INCOMING INSULATED CONDUCTORS TO EACH OF A PLURALITY OF DEPARTING INSULATED CONDUCTORS TECHNICAL FIELD The present invention relates to the technical field of terminal blocks, or specifically to terminal blocks formed for electrically connecting each of a plurality of incoming insulated conductors to each of a plurality of departing insulated conductors. In particular, ths invention relates to a terminal block of the kind having slotted parts coacting in pairs, these parts being implemented such that when an insulated conductor is inserted they penetrate the insulation and make electrical contact with the conductor.

BACKGROUND ART Terminal blocks formed for electrically connecting each of a plurality of insulated electrical conductors with each of a plurality of insulated electrical conductors are used in different fields.

It is well known, per se, to have contact elements with slotted parts in terminal blocks, these parts being implemented such that when an insulated conductor is inserted in the slot the parts penetrate the insulation and make electrical contact with the conductor.

A known terminal block for electrically connecting each of up to 20 incoming insulated conductors with each of up to outgoing insulated conductors is marketed by Ericsson Network Engineering under the type designating NER 25101, This known terminal block includes a contact element holder in two parts made from insulating plastics and pro vided with 20 contact elements. The terminal block has an elongate form with longitudinal and transverse partition walls in one of the two parts of the contact element holder. The longitudinal walls and the transverse partition walls separate the contact elements from each other and are provided with guide means for the elements. The latter are mutually alike, and are manufactured from a metallic sheet material with good electrical conductivity. Each contact element Includes three substantially flat. a · } rf » — '·* mutually parallel legs extending substantially in the same direction from a substantially s-shaped parent part. Two of the three legs have slotted parts coacting to join conductors to each other. The slotted part of the first of the legs Ϊ3 formed for penetrating the insulation of a conductor and creating good contact between the conductor and leg when this insulated conductor is inserted transversely. The slotted part on the second leg is formed for penetrating the insulation of, and making good contact between another conductor and the second leg when this conductor is inserted transversely. Good electrical contact can thus be achieved between two conductors via the legs and the parent part of a contact element. The third leg of each contact element is situated centrally between the first and second legs. At its free end this third leg has a cutting edge formed for transverse cutting of conductors with insulation. For fitting conductors into the terminal block there is a special tool without moving parts, this tool being marketed by Erisson Network Engineering under the type designation LSY 138251 With the aid of this tool and the cutting edge on the centre leg of each contact element an insulated conductor can be cut, and come into good contact with the contact element rapidly and simply in a single operation.

Terminal blocks for electrically connecting pairs of insulated conductors are also known from European patent application EP 0041596. An embodiment of a terminal block illustrated In figures 1, la, 3 and 4 of EP 0041596 has a contact holder comprising a plurality of contact elements of two types coacting in pairs, each contact element of a first type 18 having a first leg 19 with a slotted portion 22 being formed for penetrating the insulation of and making electrical contact with an incoming insulated conductor 16 for transverse insertion of this conductor in the slot, each contact element of a second type 26 having a slotted portion 27 being formed for penetrating the insulation of and making electrical contact with a departing insulated conductor 17 for transverse insertion of this conductor in the slot, each contact element of the second type having a sprung portion 28 being formed for spring biassed engagement against a portion of a contact element of the first type, the engagement establishing electrical connection between the slotted portions of contact elements of both typesDISCLOSURE OF INVENTION Terminal blocks of the NER 25101 type from Ericsson Network Engineering have several valuable properties and function excellently in the fields of use for which they are intended. For measuring purposes, however, they lack the facility of temporarily electrically insulating a conductor in the slotted part of the first leg from another conductor in the slotted part of the second leg of the same contact element. The invention has the object of providing a terminal block which has this facility, in addition to having the remaining valuable properties of the known terminal block NER 25101 from Ericsson Network Engineering.

Terminal blocks according to EP 0041596 may also have valuable properties and function good in the fields of us® for which they are intended. For the purposes of mounting the insulated conductors, however, they lack the facility of transversely cutting of both a conductor and its insulation. Th© invention has the object of providing a terminal block which has this facility.

One object of the present invention is to provide a terminal block for electrically connecting each of a plurality of electrical conductors to each of a plurality of electrical conductors, in which terminal block making contact and cutting takes place rapidly and simply in a single operation with th® aid of slotted parts in the contact element and cutting edges in the terminal block, and where a pair of electrically connected conductors can be temporarily electrically insulated from each other without removing the conductors from the slotted parts.

Another object of the present invention is to provide a terminal block for electrically connecting each of a plurality of electrical conductors to each of a plurality of electrical conductors, this terminal block being adapted for temporarily insulating electrically connected conductors from each other by the insertion of a narrow, elongate, measuring contact means, such that this means will be guided into electrical communication with each of the temporarily insulated conductors. 4“ A still further object of the present invention is to provide a terminal block which is comparatively simple and cheap to .manufacture in relation to its properties, and which has an implementation enabling S the contact elements to ©void damage when electrically connected conductors are temporarily insulated from each other on repeated occasions.

According to tha present invention, there is provided a terminal block implemented for electrically connecting each of a plurality of incoming insulated electrical conductors to each of a plurality of departing insulated electrical conductors, said terminal block including a contact element holder with a plurality of contact elements of two types coacting in pairs, each contact element of a first type having a first leg with a slotted portion being formed for penetrating the insulation of and making electrical contact with a departing insulated conductor for transverse insertion of this conductor in the slot, each contact element of a second type having a slotted portion being formed for penetrating the insulation of and making electrical contact with an incoming insulated conductor for transverse insertion of this conductor in the slot, each contact element of the second type having a sprung portion being formed for spring biassed engagement against a portion of a contact element of the first type, the engagement estaclishinc electrical connection between tne slotted portions of contact elements of both types, characterised in that each contact element of the first type has a second leg with a cutting edge formed for transverse cutting-off of both a departing conductor and its insulation, in that the sprung portion cf a contact element of the second type is formed for engaging against the leg with cutting edge of the coacting first type contact element, and in that the - 4a. element holder includes for each pair of coacting contact elements a part with a second cutting edge formed for transverse cutting off of both an incoming conductox* and its insulation, the second cutting edge being situated at a distance from, and between the lag with a cutting edge and the slotted portion of the second type contact element in a coacting pair of contact elements.

Preferably, the contact elements of the first type are substantially U-shaped. The contact elements of the seeond type are substantially hook-shaped- Xn such a case the sprung part is formed for engagement against the leg with a cutting edge at a spacing from the edge which at least attains to about half the length of the leg.

Preferably, the elements of the first type are substantially U-shaped. The leg with a cutting edge includes a spring tongue with a free end facing away from the sharp edge and extending away from the cutting edge at an angle of some degrees towards the rest of the leg with a cutting edge so that the free end of the spring tongue is closer to the sprung part than the remainder of the leg with a cutting edge. Furthermore, the sprung part is formed such as to be taken by spring bias into engagement against the spring tongue on the leg with a cutting edge.

In a preferred embodiment, the terminal block has an elongate shape with longitudinal walls and transverse partition walls in the contact element holder, said wails separating pairs of coacfing contact elements from other pairs of coacting contact elements, The parts with cutting edges extend in the longi5 tudinai direction of the terminal block between adjacent parting walls» In a preferred embodiment of a terminal block in accordance with the invention., at least the transverse partition walls are formed with guide means for the slotted parts and the leg with a cutting edge, these guide means being formed such that they substantially fix the mutual spacing between the slotted parts and the leg with a cutting edge as well as the part with the cutting edge., but do not fix the position of the spring tongue or the sprung part relative the remainder of the coacting contact elements. In addition, the part with the cutting edge is formed with a guide surface, facing towards the leg with a sharp edge and disposed at a distance from the leg with a cutting edge and with an orientation thereto such that a sufficiently narrow and elongate measuring contact means, which is thrust between the leg with a cutting edge and the part with the cutting edge, is guided towards the engagement area between the sprung part and the spring tongue.

Implementing a terminal block in accordance with the invention, and especially in accordance with the preferred embodiments, signifies several advantages.

An important advantage of a terminal block in accordance with the invention compared with the known terminal NER 25101 is that conductor’s inserted into pairs of coacting slotted part can be temporarily insulated from each other without removing any conductor from any slotted part, It Is here a particular advantage that the terminal block is formed such that the conductors can be insulated from each other by the insertion of a narrow and elongate measuring contact means, enabling the latter to come into electrical communication with the conductors. A further advantage in this respect is that the part with the cutting edge can function as a guide means for such a contact means, so that the risk of damage and wear on the contact elements is reduced.

In relation to terminal blocks other than the above mentioned NER 25101, a terminal block in accordance with the invention also has substantially the same advantages as the terminal block NER 25101.

An important advantage of a terminal block in accordance with the invention compared with the mentioned terminal block of EP 0041596 is that an isolated conductor can be inserted and contacted in a slot and cut off at a distance from the slot in a single operation» This is due to the cutting edge leg and part with cutting edge of the holder. A further advantage in this respect is that the part with the cutting edge in the holder can function as a guide means for a measuring contact means for separating the engaging portions of the contact elements, whereby damage to the engaging portions may be avoided.

Further advantages of a terminal block in accordance with the invention., and particularly with the preferred embodiments thereof» will be understood by one skilled in the art» after studying the following description of the preferred embodiments.

BRIEF DESCRIPTION OF DRAWINGS Figure 1 illustrates,, somewhat simplified, an upper part of a contact element holder in approximately the scale 1:1, seen from one long side» one short side and from above.

Figure 2 illustrates» somewhat simplified, a lower part of a contact element approximately into scale 1:1 seen from below, from one long side and from one short side.

Figure 3 illustrates to an enlarged scale the upper part of a contact element holder seen from one long side in a direction of the arrow E in Figure 1.

Figure 4 illusnacss to an enlarged scale an upper part of a contact element holder seen from one short side in a direction of the arrow F In Figure 1.

Figure 5 illustrates to an enlarged scale a part of an upper part of a contact element holder seen from above in the direction of the arrow C in Figure 1. Figure 6 illustrates to an enlarged scale a part of an upper part of a contact element seen from below in the direction of the arrow G in Figure 1» Figure 7 illustrates to an enlarged scale a cross section through an upper part of a contact element holder, this cross section being indicated by the arrows B in Figure 1» Figure 8 illustrates to an enlarged scale a part of longitudinal section through an upper part of the contact element holder, this section being indicated by the arrows D in Figure 5.

Figure 9 illustrates to an enlarged scale a partial longitudinal section through an upper part of a contact element holder, this section being indicated by the arrows M in Figure 5.

Figure 10 illustrates to an enlarged scale a part with a cutting edge seen in the direction of the arrow N in. Figure 7.

Figure 11 illustrates to an enlarged scale a lower part of a contact element holder with a partially cut away wall seen from one long side in the direction of the arrow H in Figure 2.

Figure 12 illustrates to an enlarged scale a lower part of a contact element holder with a partially cut away wail seen from the opposite long side as in Figure 11» i.e. in the direction of the arrow K in Figure 2.

Figure 13 illustrates to an enlarged scale a longitudinal section through a lower part of a contact element holder, this section being indicated by the arrows F in Figure 2.

Figure 14 illustrates to an enlarged scale a part of a lower part of a contact element holder seen from below in the direction of the arrow D in Figure 2., Figure 15 illustrates to an enlarged scale a cross section through a lower part of the contact element holder, this section being indicated by the arrows C in Figure 2.

Figure 16-18 illustrates to an enlarged scale a contact element of a first type seers from a leg with a cutting edge, seen from one side and from a leg with a slotted part, respectively.

Figures 19-21 illustrate to an enlarged scale a contact element of a second type seen from a leg with a slotted part, seen from one side and from a sprung part, respectively.

Figure 22 illustrates making contact and cutting off an incoming conductor in a terminal block with contact element holder and contact elements.

Figure 23 Illustrates making contact and cutting off a departing conductor in a terminal block with element holder and contact elements.

Figure 24 illustrates a terminal block with fitted incoming conductor and outgoing conductor and overvoltage protector.

Figure 25 illustrates a terminal block with a fitted incoming conductor and outgoing conductor and a marking plug.

Figure 26 illustrates a 4-pole measuring contact contact means seen in the direction of the arrows S in Figure 27.

Figure 27 illustrates a 4-pole measuring means according to Figure 26 seen in the direction of the arrow R in Figure 26,, BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of a terminal block in accordance with the invention is illustrated in Figures 1-21. Attachment and cutting off of insulated conductors in the terminal block is illustrated in Figures 22 and 23. In Figures 24 and 25 it is respectively illustrated how an overvoltage protector 24 and a marking plug 42 can be attached to the terminal block.

The terminal block according to Figures 1-=21 has, at least superficially, great likeness to the known terminal block with the type designation MER 25101 The terminal block has., as with the known terminal block, a contact element holder comprising an upper part 1 and a lower part 2. The upper part has an elongate shape with longitudinal walls 3 end transverse partition walls 4. Between these walls the upper part of the contact element holder has spaces 12 in which contact elements can be Inserted from the underside of the upper part when the upper part is separated from the lower part of the holder. The upper part is formed on its underside for being inserted from above into the lower part of the holder. For retaining the upper part in the lower parts, the upper part has on each of its longitudinal walls four locking shoulders 5, while the lower part has four locking holes 6 in each of it long side walls 7. The sizes position and aritentation of the locking holes in the side walls Is adjusted to the size, position and orientation of the locking shoulders, such that shoulders and holes together will provide a snap lock of the upper part against the lower part. The bottom 8 of the lower part has a plurality of upstanding bottom parts 9, the length, width, height and position of which are adjusted to the spaces 12 In the upper part between the longitudinal walls 3 and the transverse partition walls 4„ When the upper part is inserted to Its locking position in the lov/sr part, the upstanding bottom parts 9 each thrust into one of the spaces 12 and prevent any contact element from being removed from the spaces. There is a ventilation hole 10 In each of the upstanding bottom parts.

The longitudinal walls of the upper part of the contact element holder are upwardly formed with a plurality of blunt serrations 11, extending in a direction away from the underside of the upper part. Between the serrations there are tapering spaces in which conductors can be inserted for connection. For incoming conductors 16 inserted in the spaces between the teeth at one longitudinal wall, the lower part of the contact element holder has a common guide or collection holder 13 with a substantially rectangular guiding or collecting hole 14, this hole being adapted for enabling ail incoming conductors to extend through it» For the incoming conductors, the lower part of the contact element holder further has a plurality of individual conductor guides or holders 15 at the upper edge of its one side wall, in Figures 23-25 there is somewhat simply illustrated how an incoming conductor extends through the collection hole and past an individual conductor guide and Is Inserted between two teeth of a longitudinal wall. From these figures it will also be seen how an outgoing conductor 17 can be inserted between two teeth of the opposing longitudinal wail of the upper part of the contact element holder.

A terminal block according to Figures 1-21 is Intended to have two different types of contact element in the contact element holder. A first type of contact element 18 is illustrated in Figures 16-18. This contact element Is manufactured from metallic sheet material with good electrical conductivity. It is substantially U-shaped, with two substantially flat parallel legs 19 and 20 of somewhat different lengths. Between the legs the contact element 18 has a connecting part 21 of the same material thickness as the legs 19 and 20 but with less width than the legs. The leg 19 has, beginning at Its free end, a slotted part 22«, which is formed such that when an outgoing insulated conductor is inserted transversely in the slot from the open end of the slot it can penetrate the insulation round the conductor and make good electrical contact with this conductor.

The leg 20 of the contact element of the first type is somewhat shorter than the leg 19. The leg 20 has a central part formed as a spring tongue 23, and its free end formed as a sharp edge 24. The spring tongue is joined to the rest of the leg 20 at the end of the tongue nearest to the sharp edge., The spring tongue has a length such that its free end 25 is at a distance from the sharp edge greater than half the length of the leg 20. The spring tongue extends in a direction away from the sharp edge, nearly parallel to the remainder of the leg 20 but at an angle of some degrees towards the rest of the leg so that the free end of the spring tongue is somewhat away from the leg 19 than surrounding parts of the leg 20. The spring tongue has a substantially rectangular shape with a width attaining to about 30 % of the width of the leg 20.

A second type of contact element 26 is illustrated in Figures 19-21. This is also manufactured from sheet metallic material with good electrical conductivity, prefereably the same material as the contact element of the first type. The second type contact element can be said to be substantially hook shaped with a straight slotted part 27. The slotted part 27 has substantially the same width and length as the leg 19 of the first type contact element. The slot in the part 27 is so ms what differently formed, however, and shorter than the slot in the part 22, so that an incoming conductor 16 will not come directly opposite the corresponding departing conductor 17 when the conductors are fitted into the terminal block for being connected to each other.

The second type of contact element has a sprung part 28 extending from the slotted part 27. The sprung part is partially bent and partially straight with a varying width, which is less than the width of the slotted part 27. In the vicinity of the free end of the sprung part it is formed as a convex contact portion 29.

The contact elements of the first and second type are formed for coacting in pairs, one of each to a pair, in the contact element holder, the sprung part is intended for being taken by spring bias info engagement against the leg with a sharp edge of the coacting first type contact element. The sprung part is formed for engaging against the spring tongue 23 of the leg 20, at a distance from the sharp edge 24 attaining to at least half the length of the leg 20, which is apparent from Figures 22-25 for example. When the sprung part engages the cutting edge leg 20 electrical connection Is established between the slotted part 22 of one contact element and the slotted part 27 of the corresponding coacting contact element.

To give the contact elements desired orientation and spacing relative each other in the contact element holder, the longitudinal walls 3 and the partition walls 4 of the upper part of the contact element holder are provided with guides for the contact elements. These guides are seen most clearly in Figures 5-7. The desired orientation and positions of the contact elements in the guides are perhaps most clear from Figures 22-25. The guides include tapering grooves 30 in the partition walls 4, and tapering grooves 31 and 32 in the junction area between the partition walls and the longitudinal wails. The tapering grooves extend substantially parallel from the underside of the upper part of the contact element holder to the upper side of its upper part. Nearest the lower side of the contact holder the grooves have parts which taper conically towards the upper side. Nearest the upper side, the grooves have parts which do not notably or only insignificantly taper towards the upper side. The guides also include flanges 33 and 34 on the partition walls, these flanges extending along the parts of the grooves 31 and 32 which are nearest the upper side of the upper part of the contact element holder, where the grooves 31 and 32 do not taper or have substantially less taper than nearest the underside of the contact element holder upper part.

The central grooves 30 are intended for the legs 20 with the spring tongue 23 and cutting edge 24. The grooves 31 and flanges 33 are intended for the legs 19 with slotted parts 22. The grooves 32 with flanges 34 are intended for the slotted parts 27 of the second type contact elements. When the contact elements are inserted in the intended manner in the grooves, and the upper part of the contact element holder is inserted and snap locked into the lower part of the holder, the guides and the bottom parts 9 of the lower part fix the mutual spacings and positions of the slotted parts 22 and 27 as well as the upper part with a cutting edge 24 on the leg 20. The fixing of the legs 20 and 22 as well as the part 27 of the contact elements during mounting and cut off of insulated conductors are perhaps best illustrated in Figures 22 and 23. When the isolated conductor 17 is cut off by the cutting edge 24 of leg 20 the lower emd of leg 20 is supported by the bottom of the holder. The depth of the grooves in the partition walls, the absence of flanges at the parts of the grooves nearest to the underside of the upper part and the lesser width of the sprung part 28 and spring tongue 23 result, on the other hand, in that the guides and holder bottom do not fix the position of the spring tongue 23 in a similar manner, neither do they fix the position of the sprung part 28 relative the remainder of the coacting contact elements.

For each pair of coacting contact elements, the upper part of the contact element holder has a part 35 extending like a bridge in the longitudinal direction of the terminal block between two adjacent partition walls. In Figure 6 will be seen a cross section through a part 35, this cross section being situated approximately halfway between two partition walls. The contour of the part 35 seen from above is seen in Figure 5 and from below in Figure 6. In Figure 10 there ie illustrated a part 35 between two partition wails seen from one side, Le, in the direction of the arrow N In Figure 7» The part 35 has a flat upper side facing towards the upper side of the upper part of the contact element holder. The junction between the flat upper side and the side surface of the part 35 facing towards the grooves 32 and flanges 34 is formed such as to function as a cutting edge 36 when incoming conductors are fitted to the terminal block. When an incoming insulated conductor is Inserted In the slotted part 27 aid is moved transversely In the direction of the slot against the lower part of the contact element holder, using a tool of the type LSY 138251. the conductor with insulation is cut off by coaction between the tool and the cutting edge 36 of the part 35. This is illustrated somewhat simplified in Figure 22, In this respect, the cutting edge 36 coacts with the too! in a similar way as the cutting edge 24 coacts with the tool on insertion of a departing conductor with insulation in the slot in the part 22. This cutting-of coaction is Illustrated in Figure 23» The side surface of the part 35 facing towards the groove 30 is formed as a guide means surface 37. When the contact elements are inserted in the contact element holder, the guide surface 37 is facing towards the leg 20 with a cutting edge of the first type contact element 18. The guide surface is situated at a distance from the leg 20 and is oriented relative th® leg such that a suffiently narrow and elongate measuring contact means, which is thrust between the leg 20 and part 35, is guided towards the area where the sprung part 28 engages against the spring tongue 23. Particularly good guiding action can be obtained if the measuring contact means has a substantially para lie lepipedic pert with the following propertiess its width is suited to the distance between two adjacent partition walls, its thickness is suited to the distance between the guide surface 37 and the upper part of the leg 20 with a cutting edge, its length is suited to the distance between the upper side of the contact element holder upper part and the contact area between the contact portion 29 of the sprung part 28 and the spring tongue 23, and its insertion end is chamfered or rounded. Such a measuring contact means can be effectively guided to the contact area and thrust between the contact portion 29 and the spring tongue 23, so that these are electrically insulated from each other without any great risk for damagae to the sprung part or the spring tongue. Such effective guidance would not be obtained without the part 35 with the guide surface 37. If the measuring contact means is provided with contact surfaces electrically insulated from, and facing away from each other, as well as respectively facing towards the contact portion 29 and the spring tongue 23, electrical contact can be obtained via the contact means between incoming and departing conductors via the contact portion of the sprung part and via the spring tongue 23 of the leg 20, respectively, when incoming and departing conductors are electrically insulated from each other in the terminal block. Due to the effectvie guidance of the measuring contact means with the aid of the part 35 with the guide surface 37, such electrical contact can be suffientiy good, durable and reproducable for being able to be used to advantage for measuring purposes.

An example of such a measuring means is illustrated in Figures 26 and 27. The measuring means in these Figures has a gripping part 38 and two insertion parts 39 with substantially para lie lep sped ic shape and chamfered free ends. Each insertion part has two contact surfaces 40 electrically insulated from each other. These surfaces comprise metal coatings on the wide sides of the insertion parts, and are each electrically connected to a conductor In a connection cord 41. The length L of the insertion parts is suited to the distance between the upper side of the upper part of the contact element holder and the area where the contact portion 29 and free end 25 of the spring tongue are in the terminal block. The distance of the insertion parts from each other is suited to the thickness of the partition walls 4 and the width W of the Individual insertion parts is suited to the distance between adjacent partition walls so that the insertion part can be inserted into adjacent intermediate spaces 12 in the terminal block. The thickness T of the insertion parts is suited to the distance between the leg with a cutting edge and the part with the cutting edge of the terminal block.

When It is desired to electrically insulate an incoming conductor in contact with the slotted part 27 from a departing conductor in contact with the corresponding slotted part 22, for purposes of measuring of other reasons, it is important chat the cut-off free ends of incoming conductor and outgoing conductor cannot touch each other and cause electrical communication between the conductors. In a terminal block according to Figures 1-21 there is no risk of the cut-off conductors coming into contact with each other due to the incoming conductor being cut off against the cutting edge 36 of the part 35 while the departing conductor is cut off against the sharp edge 24 of the leg 20, and this edge is at a considerable distance from the cutting edge 36, partly due to the thickness of the part 35 and partly due to the space between the part 35 and the leg 20, The cut off free ends thus automatically come at a considerable distance from each other.

An important advantage of the embodiment of the coacting contact elements illustrated in Figures 16-23 and described above, is that an overvoltage protector 42 e.g. an overvoltage cassette, of the type NFD 25111 from Ericsson Network Engineering, can be connected via the leg 20 without affecting the contact between the contact portion 29 of the sprung part and the spring tongue 23 of the leg 20» Another important advantage is that the whole movement required for separating the contact portion 29 and the spring tongue 23 from each other does not need to be executed by the sprung part 28 Particularly advantageous is that the distribution of the necessary separating movement is not determined by the relation between the spring forces in the sprung part and the spring tongue» Due to the guidance of a measuring contact means with the aid of the guide surface 37 on the part 35 the spring tongue can be forced to move in a direction towards the leg 19 when the spring contact means is inserted, even though the spring bias in the spring tongue will then be considerably groater than the spring bias in the sprung part 28 of the second type contact element» In this way the risk can be substantially reduced of the material in the sprung part 28 having its elastic limit exceeded in conjunction with separating the contact part and the spring tongue» The invention is not restricted to terminal blocks entirely agreeing with what has been illustrated in Figures 1-25, and it is conceivable to form terminal blocks somewhat otherwise in certain respects. For example, it Is conceivable to design terminal blocks for more or less than twenty Incoming conductors. It is not absolutely necessary to keep both parts of the contact element holder together with the aid of four locking shoulders and locking holes on each side. Neither is it absolutely necessary to have common conductor guidance or conductor holders 13 with collection holes 14 and individual conductor guides 15 of the kind illustrated for incoming conductors. Further modifications are conceivable within the scope of the claims.

Claims

1. A terminal block implemented for electrically connecting each of a plurality of incoming insulated electrical conductors (16) to each of a plurality of departing insulated electrical conductors (17), said terminal block including a contact element holder (1,2) with a plurality of contact elements of two types coacting in pairs, each contact element of a first type (18) having a first leg (19) with a slotted portion (22) being formed for penetrating the insulation of and making electrical contact with a departing insulated conductor K ( 17) for transverse insertion of this conductor in the slot, each contact element of a second type (26) having a slotted portion (27) being formed for penetrating the insulation of and making electrical contact with an incoming insulated conductor (16) for transverse insertion of this conductor in the slot, each contact element of the second type having a sprung portion (28) being formed for spring biassed engagement against a portion of a contact element of the first type, the engagement establishing electrical connection between the slotted portions of contact elements of both types, characterised in that each contact element of the first type has a second leg (20) with a cutting edge (24) formed for transverse cutting-off of both a departing conductor and its insulation, in that the sprung portion of a contact element of the second type is formed for engaging against the leg with cutting edge of the coacting first type contact element, and in that the element holder includes for each pair of coacting contact elements a part (35) with a second cutting edge (36) formed for transverse cutting off of both an incoming conductor and its insulation, the second cutting edge (36) being situated et a distance from, and between the leg with a cutting edge and the slotted portion of the second type contact element in a «16coacting pair of contact elements.

2. A terminal block as claimed in claim 1, characterised in that the first contact element (18) is substantially U-shaped, in that the second type contact element (26) is substantially hook-shaped, in that the sprung part (28) is formed for engagement against the leg (20) with a cutting edge at a distance from the cutting edge (24) attaining to at least half the length of the leg.

3. A terminal block as claimed in claim 1, characterised in that the first type contact element (18) is substantially U-shaped, in that the leg (20) with a cutting edge includes a spring tongue (23) with a free end (25) facing away from the cutting edge, said spring tongue extending in a direction away from the sharp edge at an angle of some degrees towards the remainder of the leg (20) with a cutting edge so that the free end of the spring tongue is closer to the spring part (28) than the remainder of the leg with a cutting edge, and in that the sprung part is formed for being taken by spring bias into engagement against the spring tongue on the leg with a cutting edge.

4. A terminal block as claimed in claim 1, characterised in that it has an elongate form with longitudinal walls and transverse pax'tition walls (4) on the contact element holder, said walls separating parts of coactinc contact elements from other pairs of coactinc contact elements, and in that the parts (35) with cutting edges extend in the longitudinal direction of the terminal block between the parting walls.

5. a tezaainal block as claimed in claim 4, characterised in that at least the partition walls are formed with guides (30,31,32,33,34) fox the slotted parts and the leg with a cutting edge, said guides being formed such that they substantially fix the mutual spacing between the slotted parts (22,27) and -17leg (20) with a cutting edge (24) and the part (35) with a cutting edge, but do not fix the position of the spring tongue (23) or the sprung part (28) relative to the remainder of the coacting contact elements, in that 5 the part with s cutting edge is formed with a guide surface (37), said guide surface facing towards the leg (20) with a cutting edge, arranged at a distance therefrom and with an orientation relative to said leg such that a sufficiently narrow and elongate measuring 10 contact means, which is inserted between the leg with a cutting edge and the part with a cutting edge, is guided towards the engagement area between the sprung part and the spring tongue.

6. A terminal block substantially as herein 15 described with reference to, and as shown in, the accompanying drawings.