US 3603918 A
Description (OCR text may contain errors)
0 11mm States Patent  Inventor Hans Woertz Basel, Switzerland  Appl. No. 829,981  Filed June 3, 11969  Patented Sept. 7, 19711  Assignee Osknr Woertz, 11th., 111. 0: 0.
Basel, Swltzeflandl  Priority Dec. 6, 11969  Switzerland [31 110225/68  ELECTIMC POWER DHSIIMIBUTII'ON SYSTEM 1141 Cllmlms, 14 Drawing Figs.
 ILLS. C1 3319/22 '11, 339/ l 4 R  11nt.C1 ..1'11011r13/60  Fieldotlsenrch 339/14,21,
llkefierences Cited UNITED STATES PATENTS 12/1960 Elder 24/73 5/1963 Hickey et al.... 307/147 1/1969 Sprigings et a1. 339/141R 3/1970 Routh etal. 339/14R FOREIGN PATENTS 2/1962 France 339/14 R Primary Examiner- Ernest R. Purser Assistant ExaminerRobert A. Hafer Attorney-Watson, Cole, Grindle & Watson ABSTRACT: Electric power distribution system having at least one current-carrying bar with a continuous elongated slot and corresponding contact parts on current collectors to cooperate with the current-carrying bar.
PATENTEUSEP nan SHEET 1. OF 3 INVENTOR.
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SHEET 3 [IF 3 INVENTOR. H 715 Woekfz FIIECTIIIC IPGWIEII lDISTIIIIIIJ'IION SYSTEM The present invention relates to an electric power distribution system comprising at least one current-carrying bar, which has a hollow sectional portion, which is provided with a continuous elongated slot at the front side and in the interior of which extend at least two mutually insulated electrical conductors, which are adapted to be brought into contact with corresponding contact parts on current collectors which may be detachably fitted on any point along the current-carrying bar, and comprising at least one connecting device for electrically connecting the leads of the currentcarrying bar or for coupling the leads with those of another current-carrying bar of this kind.
In similar known wiring systems, the connecting device in corporates terminals in which the leads of the current-carrying bar are clamped, and for this purpose it is necessary for the leads to project beyond the hollow sectional portion at the end of the current-carrying bar concerned. Consequently it is not possible to cut the current-carrying bar to the required length when in the assembled condition. The leads and the hollow sectional portion have to be cut separately to different lengths. The same thing applies in the case of the great variety of designs of known connecting devices, including those wherein the terminals are connected to plug pins and coupling sockets respectively for plugging together a plurality of current-carrying bars. When several current-carrying bars are plugged together to form a fairly long length by means of plug pins and coupling sockets and are fitted in the building, it is also difficult and often impossible to remove a single one of these current-carrying bars from the run should this be necessary, without likewise having a take out the other current-carrying bars of the run.
The object of the invention is to overcome the above-mew tioned disadvantages and difficulties and to enable the connecting or coupling of the current-carrying bars to be carried out properly and conveniently, even if the leads of the currentcarrying bars are of the same length as the hollow sectional portion ofthe bar.
The electric wiring system in accordance with the invention is mainly characterized in that the connecting device comprises a housing which consists of electrically insulating material and which can be pushed from one end of the current-carrying bar into the hollow sectional portion thereof to make a good fit therewith and contains contact elements which can be brought into contact with the leads of the current-carrying bar through appropriate orifices in the housing and connect with connecting parts likewise disposed in the housing.
In a preferred arrangement, the connecting device comprises at least one locking screw which can be turned even when the housing is pushed into the hollow sectional portion and prevents unintentional slicing of the housing in the hollow sectional portion. Fxpediently, at least one of the contact elements is adapted to be moved in the housing along a line extending through the associated orifice, a spring urging the contact element back into the interior of the housing to an extent that this element is withdrawn from any contact from the exterior of the housing. In this arrangement the locking screw, with an insulating member between it and the movable contact element, if effectively connected to said element in such a manner that the latter, when the locking screw is turned when securing the housing in the hollow sectional portion, can be automatically caused to move out of the associated orifice in the housing, thereby overcoming the action of the spring, this for the purpose of establishing contact with the associated lead of the current-carrying bar. In this manner a high degree of safety is ensured against accidents involving electric current, such as could occur particularly when a current-carrying bar is unskillfully removed with the connecting device still under voltage.
Further advantages, details and features of the wiring system of the invention will be seen from the claims, from the following description of examples of construction and from the associated drawings, in which the subject matter of the invention is illustrated purely by way ofexample.
FIG. I illustrates, in cross section on the line I--I of FIG. 3, a current-carrying bar having two insulated leads and a protective earth lead;
FIG. 2 shows the same current-carrying bar in cross section, and a current collector inserted in the current-carrying bar, in elevation;
FIG. 3 shows a portion of the current-carrying bar in elevation from the front side, i.e. from below in FIG. I or 2, with an inserted connecting device and the current collector in section on the line IllIII of FIG. 2;
FIG. d illustrates a longitudinal section through one end portion of the current-carrying bar with the connecting device inserted, the latter being shown mainly in elevation and partly in section;
FIG. 3 shows the connecting device only in side elevation;
FIG. I5 illustrates, on a larger scale, the current-carrying bar and the inserted connecting device in cross section on the line VI-VI of FIG. 3;
FIG. 7 shows the connecting device, separated from the current-carrying bar, in longitudinal section on the line VII-Vii of FIG. b;
FIG. is a similar longitudinal section of the line VIII-VIII of FIG. Ii;
FIG. 9 shows a part of the connecting device in the detached, opened condition;
FIG. III illustrates two current-carrying bars which abut each other over a straight line and are interconnected with the help of two connecting devices;
FIG. I1 shows a similar arrangement for connecting and coupling two current-carrying bars at right-angles;
FIG. 12 illustrates a T-connection of three current-carrying bars;
FIG. 13 illustrates a similar cruciform connection of four currentcarrying bars;
FIG. I I shows a straight line connection of two current-carrying bars with a terminal fitted therebetween for connecting an input or output cable.
The current-carrying bar or track Ill shown in FIGS. I and 2 comprises a hollow sectional portion II of metal, which has a continuous elongated slot I2 at its front side, facing downwards in FIG. I. In the interior of the hollow sectional portion II are two current-carrying electric leads I3 and I4 and a protective earth lead I5, all of which are in the form of flat bars and extend in the longitudinal direction of the current-carrying bar. The two current-carrying leads I3 and Id are sunk into channel-shaped insulating members In, which are disposed on both sides of the elongated slot I2 directly behind the inwardly extending longitudinal edges I7 of the hoilow sectional portion, the arrangement being such that it is impossible for the leads I3 and III to be touched by human hand through the slot I2. The protective earth lead I5 is contained in a complementary groove in the spine I3 of the hollow sectional portion opposite the elongated slot I2. Within the hollow sectional portion II there is also a longitudinal rib I9 which produces intentional asymmetry in the current-carrying bar, the significance of which will be explained below. The outwardly facing side of the spine III is provided with two longitudinal ribs 20 having flanges ZI, which can be used for securing and supporting the current'carrying bar.
The current-carrying bar or track described is intended to accept inserted current collectors which can be fitted at any point along the bar. An example of the construction of such current collector 30 is illustrated in FIGS. 2 and 3.
The current collector 30 comprises a hammer-shaped insulating element 3I on which are disposed two current-carrying contact parts 32 and 33 and a protective earth contact element 3d. At least the protective earth contact element 34 is resiliently mounted on the insulating element 311. The insulating element 31 is provided with a hollow stem 35, at the free end portion of which is mounted a grip 36 in the form of a rotatable know, as shown in FIG. 2. The stem 35 passes through a washer 37. A helical compression spring 38 surrounds the stem 35 and is supported by its ends on the grip 36 and the washer 38. A three-core electric cable 39 is inserted in the bore of the stem 35, the electrically conducting cores of this cable being connected to the contact members 32, 33, and 34 respectively. The cable 39 is used for example for suspending and supplying an electric light, not illustrated, or supplying some other electricity-consuming unit. The hammer-shaped insulating element 31 is so shaped that it can be inserted from the front side of the current-carrying bar into the elongated slot 12 of the hollow sectional portion 1 1 and, when it is inside said portion 11, then turned through 45, the protective earth contact element 34 is disposed coaxially with the stem 35 in such a manner that when the current collector is inserted in the current-carrying bar the element 34 is brought into con tact with the protecting earth lead 15 in the bar. The two other contact members 32 and 33 are disposed on the insulating element 31 in such a way that when the element 31 is turned, they are positioned opposite the two current-carrying leads l3 and 14 and come into contact therewith under the action of the helical compression spring 38, when the grip 36 is released.
The hammer-shaped insulating element 31 of the current collector 30 has, at one of its free ends, a recess 40 into which the longitudinal rib 19 on the hollow sectional portion 11 can move when the current collector is in its working position. A corresponding recess is not provided on the other opposite free end of the insulating element 31. This prevents the current collector from possibly being inserted the wrong way around. In other words, each of the contact members 32 and 33 can be brought into contact only with a certain one of the current-carrying leads 13 and 14.
A special connecting device is provided for connecting the current-carrying bar or track 10 to a main supply, and this device will now be described by reference to FIGS. 3 to 9.
The connecting device comprises a housing 50 which consists of electrically insulated material and, as shown in FIGS. 3, 4 and 6, can be inserted from one end of the current-carry ing bar 10 to fit in the interior of the hollow sectional portion 11. The housing 50 is composed of two dished parts 50a and 50b, which are held together with the help of screws 51 and nuts 52 (FIGS. 3 and 8). One of the sidewalls of the housing 50 containsa longitudinal groove 53 into which the rib 19 on the hollow sectional portion 11 can enter. The opposite sidewall of the housing 50 does not contain a corresponding recess, so that the housing is prevented from being inserted the wrong way round in the hollow sectional portion 1 1. Three bladelike contact elements 54, 55, and 56 are present in the housing 50, and these can be brought into the contact with the leads 13, 14 and 15 respectively of the current-carrying bar 10 through associated orifices 57 and 58 (FIGS. 7 and 8).
The two contact elements 54 and 55 which are intended to cooperate with the current-carrying leads 13 and 14 of the bar 10, take the form of metal tabs 59, bent up at right angles, which are secured by means of rivets 60 (FIG. 9) on a common flat web 61 of insulating material. T he web 61 is movable within the housing 50, so that the contact elements 54 and 55 are movable jointly with the web 61. A guide sleeve 62, having an axial, internally threaded bore 63, is secured perpendicularly at the center of the web 61. The guide sleeve 62 can slide in a central orifice in a hublike boss 64 (FIG. 7) on the part 50b of the housing and is surrounded by a helical compression spring 65, which is interposed between the web 61 and that wall of the housing 50 which carries the boss 64. The spring 65 urges the web 61, with the contact elements 54 and 55 secured thereto, into a position in which the contact elements 54 and 55 are moved into the housing 50 to an extent such that they no longer project from the associated recesses 57 and are thus withdrawn from any contact from the outside, this being clearly shown in FIG. 8.
Special steps are taken in order to cause the contact elements 54 and 55 to move out of the housing 50 and to bring them into contact with the current-carrying leads l3 and 14 of the bar 10. For this purpose, a screw 66 (FIGS. 4, 5 and 6) is screwed into the threaded portion of the bore 63 of the guide sleeve 62, which screw extends through a clamping member 67 in the form of a plate. When the housing 50 is pushed into the hollow sectional portion 11 in the working position, the screw 66 projects through the elongated slot 12 and, from the outside, causes the clamping member 67 to bear against the edges 17 on both sides of the elongated slot 12, this being shown the most clearly in FIG. 6. When the screw 66 is turned, the web 61 is moved towards the clamping member 67, overcoming the force of the spring 65, so that the contact elements 54 and 55 are caused to move out of the housing 50 and finally to move into contact with the leads 13 and 14 of the currentcarrying bar. When the screw 66 is fully tightened, the current-carrying bar is clamped between the contact element 54 and 55 on the one hand and the clamping member 67 on the other, so that the connecting device and therefore the housing 50 are secured against inadvertent sliding on the current-carrying bar. The screw 66 therefore also acts as a locking screw for securing the housing in the hollow sectional portion 11. Formed on the clamping member 67 is a guide rib 68, which must penetrate the elongated slot 12 in the hollow sectional portion 11 in order to lock the clamping member 67 against rotation when the screw 66 is being tightened. It has also to be mentioned that the housing 50 has two projecting longitudinal ribs 69 on that of its outer faces presented to the leads l3 and 14, which ribs engage in the grooves of the insulating members 16 of the current-carrying bar and contain the orifices 57 in the through direction of which the contact elements 54 and 55 are movable.
The third contact element 56 of the connecting device is rivetted to the middle portion of a leaf-spring 70 the ends of which are secured by means of rivets 71 to portion 50a of the housing (FIG. 7). Between the contact element 56 and each of the rivetted ends of the leaf-spring 70, the latter has a stirrupshaped bend 72, imparting an increased spring-travel to the middle portion of the leaf-spring 70 therebetween and the contact element 56 secured thereto. The contact element 56 is thus to a certain extend resiliently held on the line extending through the associated orifice 56. As compared with the contact elements 54 and 55 however, the third contact element 56 cannot move so far that it could fully enter the housing 50.
The two end portions of the metal part 59 carrying the contact elements 54 and 55 each have a screw-threaded bore 73 (FIGS. 8 and 9). A clamping screw 74 with an associated pressure plate 75 is screwed into one of those screw-threaded bores 73 in each metal part 59. A clamping means is thus formed for connecting an electric conductor wire. In a similar manner, the leaf spring 70 has a screw-threaded bore 76 (FIGS. 7 and 9) in the vicinity of its two end-portions, and a clamping screw 77, with which is associated a pressure plate 78, is likewise screwed into one of these screw-threaded bores 76. A further clamping means for connecting a conductor wire is thereby formed.
At its opposite end-faces the housing 50 has particularly thin wall portions 80, as shown on the left in FIGS. 7 and 9; if required these portions can be knocked out. On the right in these figures the appropriate wall portion has been knocked out to form an opening 81 through which one end of a threecore cable 82 (FIGS. 3 and 4) is introduced. The three cores of this cable are connected to the contact elements 54 and 55 and/or 56, by means of the clamping screws 74 and 77. The other end of the cable 82 is connected to two phase leads and a protective earth lead, or to one phase lead, the neutral lead and a protective earth lead of a normal current supply system so as to provide the current-carrying bar 10 with electric ener- As seen in FIGS. 3 and 4, the cable 82 is brought in through a rubber sleeve 83, which is fitted in orifices in two angle members 84 and 85. One limb of one angle member 84 closes the end of the current-carrying bar 10 and the outside of its other limb bears against the longitudinal edges 17 of the hollow sectional portion ill. The other angle member 65 is similarly disposed, but its second limb extends into the interior of the hollow sectional portion 11!. A screw 66 is introduced through a hole in the second limb of the angle member M and is screwed into a screw-threaded bore in the corresponding limb of the other angle member 65. By tightening the screw 66, the two second-named limbs of the angle members M and 85 are drawn towards each other and thereby clamped on to the hollow sectional portion Ill. The angle member 65 is also mechanically connected to the housing 50 of the connecting device by the screw 511 on that side extending through matching bores in the second-named limb of the angle member 85, as shown in FIG. ti. A clip 87, clamped on the cable 62, bears against the sleeve 83. In this way, the part of the cable 62 extends from the clip $7 to the clamping screws M and 77 are relieved of mechanical tensile stresses which could otherwise occur when the cable 82 is being handled.
The connecting device described offers a number of advantages. Some of these are: the electric conductors 13, 114i and 115 of the current-carrying bar lltl must not and should not project beyond the ends of the hollow sectional portion 1111. It is therefore possible to cut off, in a simple manner, the required length of current-carrying bar from an assembled run, the hollow sectional portion 111, the insulating members 116, and the leads 113, 114 and 115 being cut through in one operation. Only when the locking screw 66 is tightened do the current-carrying contact elements 54! and 55 of the connecting device move out of the insulated housing fill and into contact with the leads 13 and 14 of the current-carrying bar 110. In this way touching of the contact elements S ll and 55 by the hand is precluded, and no accidents can virtually occur, even when that end of the connecting cable 82 remote from the connecting device is already connected to the current-supply system before the connecting device is fitted on the currentcarrying bar. Unintentional touching of the contact elements 54 and 55 by persons is also precluded in the case where the connecting device, under voltage, is separated from the current-carrying bar. When the housing 50 is withdrawn from the hollow sectional portion ill, the spring 65 immediately moves said contact elements 54, and 55 back into the interior of the housing as soon as the screw is loosened or the clamping member 67 slides away from the hollow sectional portion 1111. Increased safety against accidents of an electrical nature is also ensured by the fact that when the housing 50 is pushed into the hollow sectional portion lll, electrical contact between the protective earth contact element 56 and the protective earth lead 115 and the hollow sectional portion is always first established before one of the other leads l3 and 114 receives the voltage. Conversely, when removing the connecting device from the current-carrying bar the leads l3 and 14 are first separated from the connecting cable 82, and only after that is the protective earth lead 15 disconnected when the housing it) is withdrawn from the hollow sectional portion. Since the housing 50 is precluded from being inserted in the current-carrying bar the wrong way round because of the rib 119 on the hollow sectional member M and the complementary recess 53 in the housing fail, the poles of the leads i3 and M cannot be unintentionally reversed.
Two connecting devices of the ltind described can also be used for coupling two current-carrying bars of a like kind. For this purpose, it is only necessary for the right-hand end of the cable 62, as seen in FIGS. 3 and 4!, to be connected to the second connecting device in a manner similar to that in which the left-hand end of the cable is connected to the first connecting device.
An example of an arrangement of this kind is shown in FIG. it). Two similar current-carrying bars Ml and lit" abut against each other along a straight line. A housing 50' and 50" respectively is inserted in each of the facing end portions of the current-carrying bars. The contact elements of these housings 5b and 56", not visible in FIG. 116, are interconnected by a short cable H82. Instead of each connecting device having its own flat clamping member 67, a common longer clamping member 1167 is provided, and this extends over the end portions of both current-carrying bars Ill and lit" and the two locking screws 66 and 66" pass through this clamping member. The common clamping member ll67 enables a more exact. alignment along the same axis to be achieved and ensures good mechanical connection of the two current-carrying bars l0 and 110.
The variant illustrated in FIG. 111 only differs to any extent from the example shown in FIG. W in: that instead ofa straight clamping member 167 an angled common clamping member 267 is present, thus enabling the two current-carrying bars 110' and ill" to come together at right angle. At the corner of the angled clamping member 267 are two sidewalls Stilt, which fit flush against the corresponding sidewalls of the hollow sectional portions ll of the two current-carrying bars ill) and 110".
FIG. 12 shows a further similar possible arrangement incorporating a T-shaped clamping member 367 which enables two coaxially aligned currentcarrying bars it) and lid" and a third bar 16", extending at right-angles thereto, to be mechanically interconnected. The electrical connection is achieved with the help of three housings 5'0, 541!" and 56", which are inserted in the current-carrying bars, and with the help of two cables 1182 and 282, the clamping means of one housing 50"being connected to the ends of the two cables W2 and 282. At the top of the T-shaped clamping members 367 there is a wall 91 which closes the gap between the coaxially disposed current-carrying bars 110 and lit.
FIG. 13, illustrates how, with the help of a cruciform clamping member 467, four current'carrying bars, meeting at right angles, can be interconnected. In the mutually facing end-portions of all of these current-carrying bars are inserted housings have contact elements and connectors, and these connectors are interconnected by three short cables Hi2, 2&2 and 382.
Finally, in FIG. Ml there is illustrated a variation of the arrangement seen in FIG. 10. The difference as compared with the arrangement already described resides in the fact that a still longer common clamping member 567 is provided which interconnects two coaxially arranged current-carrying bars 110' and 10". Between the mutually facing ends of the currentcarrying bars is a gap 92 in which is located a multipole connector 9 4 i. Two short lengths of cable W2 and H32" run from the connector 9ll to the housings 50' and 56" respectively in the current-carrying bars. A third cable 562, which can be used for current input or current output purposes is likewise connected to the connector 94. The middle portion of the clamping member 267, lying between the ends of the two current-carrying bars Jill and lllll", is provided with lateral wall portions 95 and 96 which are flush with the sidewalls of the current-carrying bars. The cable 582 passes through a sleeve 97 which is inserted in a complementary orifice in one of the wall portions 96.
In another variation, not illustrated, of the example shown in FIG. ill, the two housings 50 and 50 can abut each other directly and can be solidly interconnected, if required, with the help of fishplates, or by means of screws, bonding means etc. Instead of the cable 163 of FIG. Ml, three individual leads can be present which electrically interconnect the mutually corresponding contact elements in the housings 5t) and 560".
lnstead of providing two solidly interconnected housings 56 and 50', use can equally well be made of a single correspondingly larger housing, which can be inserted at the same time in the two current carrying bars to be interconnected and which contain two sets of contact elements, of which the elements corresponding to each other are conductively interconnected. In a further modification of the last-mentioned arrangement, the enlarged housing can be of angular, T-shaped or cruciform configuration, in order to be inserted in two, three or four current-carrying bars arranged at right angles to each other, the electrical connection of the corresponding leads of these current-carrying bars being established with the help of appropriate seats of contact elements in the housing.
[t is clear that, apart from the above-mentioned arrangements, numerous other variations are possible. The currentcarrying bars of the wiring system described can be advantageously fitted to the ceilings of rooms, in shop windows etc., where frequent changing of the arrangement and number of lights and other current-consuming units is to be expected. Here, the hollow sectional portions 11 of the current-carrying bars can also be used as supports for covering elements. lt is however also possible and, maybe, advantageous, to fit the current-carrying bars on walls or items of furniture.
1. An electric power distribution system comprising at least one current-carrying track which has a hollow sectional portion provided with a continuous elongated slot at the front side of the track and in the interior of which extend at least two electrical conductors insulated from oneanother, said conductors being adapted to be brought into contact with corresponding contact parts of current collectors which may be detachably fitted at any point along said current-carrying track, at least one connecting device comprising a housing consisting of electrically insulated material and which can be inserted from one end of said current-carrying track into said hollow sectional portion thereof, said housing containing contact elements adapted to be brought into contact with said electrical conductors of said current-carrying track through corresponding orifices in said housing, said contact elements each being provided with connector means disposed within said housing for an input or output conductor wire, said connecting device having at least one locking screw which can be turned when said housing is pushed into said hollow sectional portion of said track thereby to prevent unintentional sliding of said housing in said hollow sectional portion, at least one of said contact elements in said housing being adapted to extend through its associated orifice, a spring tending to urge said contact element into the interior of the housing and out of contact with its associated electrical conductors, and said locking screw being operatively connected to but insulated from said movable contact element in such manner that the latter, due to said locking screw being turned when securing the housing in the hollow sectional portion of the track, is automatically caused to move out of its associated orifice in said housing thereby overcoming the action of the spring to establish contact with its associated electrical conductor of said current-carrying track.
2. An electric power distribution system according to claim 1, in which a first clamping member is provided in the form of a plate capable of being positioned transversely over the elongated slot in the hollow sectional portion of said track, said first clamping member having at least one guide rib for engagement in the elongated slot in the hollow sectional portion, said locking screw passing through an orifice in said clamping member and through the elongated slot in the hollow sectional portion when said housing is inserted into the hollow sectional portion, thereby allowing said first clamping member to be moved towards said housing by turning said locking screw in order to clamp a part of the hollow section portion into which the housing is inserted between said housing and said first clamping member.
3. An electric power distribution system according to claim 1, in which an insulating member is provided in the form of a web and carries at its end portions at least two of said contact elements which are movable together with said insulating member and are adapted to be brought into contact respectively with said electrical conductors of said current-carrying track extending on both sides of the elongated slot in the hollow sectional portion, and in which said locking screw engages the middle portion of said insulating member, and said spring being supported on said insulating member, and a wall of said housing.
4. An electric power distribution system according to claim 3, in which a guide sleeve is provided having a screw-threaded bore and is secured perpendicularly at said middle of said web-shaped insulating member, said guide sleeve being slidable in an orifice in said housing and being surrounded by said spring which is in the form of a helical compression spring.
5. An electrical power distribution system according to claim 3, in which said contact elements are in the form of bladelike metal tabs which are secured to said insulating member and each having at its end portions screw-threaded bores for selectively receiving a clamping screw for forming a portion of said connector means for an input or output conductor wire.
6. An electric power distribution system according to claim 1, in which one of said contact elements is provided for a protective ground connection secured to the middle portion of a leaf spring, said leaf spring being secured by its end portions in said housing and having at each said end portions a screwthreaded bore for selectively receiving a clamping screw for forming another portion of said connector means for an input or output conductor wire.
7. An electrical power distribution system according to claim 1, in which corresponding contact elements of at least two of said connecting devices are electrically interconnected by at least one cable.
8. An electric power distribution system according to claim 2, in which corresponding contact elements of at least two of said connecting devices are electrically interconnected by at least one cable, said at least two connecting devices having a common second clamping member which permits at least two of said current-carrying tracks to be mechanically interconnected.
9. An electric power distribution system according to claim 2, in which corresponding contact elements of at least two of said connecting devices are electrically interconnected by at least one cable, said at least two connecting devices having a second common clamping member which permits at least two of said current-carrying tracks to be mechanically intercon' nected, said second clamping member being rectilinear.
10. An electrical power distribution system according to claim 2, in which corresponding contact elements of at least two of said connecting devices are electrically interconnected by at least one cable, said at least two connecting devices having a common second clamping member which permits at least two of said currentcarrying tracks to be mechanically interconnected, said second clamping member being of angular form.
11. An electric power distribution system according to claim 2, in which corresponding contact elements of at least two of said connecting devices are electrically interconnected by at least one cable, said at least two connecting devices having a common second clamping member which permits at least two of said current-carrying tracks to be mechanically interconnected, said second clamping member being T-shaped.
12. An electric power distribution system according to claim 2, in which corresponding contact elements of at least two of said connecting devices are electrically interconnected by at least one cable, said at least two connecting devices having a common third clamping member which permits at least three of said current-carrying tracks to be mechanically interconnected, said third clamping member being of cruciform shape.
13. An electric power distribution system according to claim 8, in which a portion of said second common clamping member contains a portion of said connector means, said second clamping member being disposed between mutually facing ends of at least two current-carrying tracks to be interconnected, said connector portion being electrically connected with said contact elements in at least one of said connecting devices.
14. An electric power distribution system according to claim 1, in which said housing is adapted to be inserted at the same time into at least two of said current-carrying tracks to be interconnected and incorporates at least two sets of said contact elements, corresponding ones of which being electrically interconnected to one another and being capable of being brought into contact with said conductors of said current-carrying tracks.