EP0454205A2

EP0454205A2 - Connecting socket

Info

Publication number: EP0454205A2
Application number: EP91200829A
Authority: EP
Inventors: Franco Paolo Pardini
Original assignee: CGE Generale Elettromeccanica SpA
Current assignee: CGE Generale Elettromeccanica SpA
Priority date: 1990-04-23
Filing date: 1991-04-10
Publication date: 1991-10-30
Also published as: IT9020111A0; IT1239718B; IT9020111A1; EP0454205A3; JPH04230971A

Abstract

Connecting socket comprising two conducting strips (16a, 16b), actuated by at least two resilient strips (22a, 22b), fastened to opposed sides of an electrically conducting body (14), being said conducting strips (16a, 16b) and resilient strips (22a, 22b) longitudinally shared for sharing the electric currents flowing through the conducting strips (16a, 16b) in order to reduce the electrodynamic repelling forces which can be developped between the strips of the socket and a conducting blade member (30) thereinto inserted owing to overcurrent conditions, as short circuit currents. Double insertion sockets, comprising two opposed members coming out from opposite sides of a conducting body connecting the two members, are further provided.

Description

Present invention refers to a connecting socket which can be either mounted to the end of a conducting rod, or be a double insertion socket, being said socket provided to fasten a conducting blade of a bus-bar coming out either from an electric machine or an electric insertable device or eqiupment.
Connecting sockets, used to connect two electric conductors, are well known since long time, being one of the conductors usually fixed and the other movable, and being for example one comprised within a control board and the other associated to devices insertable with respect to said board.
Essentially a connecting socket comprise at least a block or central body, substantially planar, of parallelepidal shape, in good electrically conducting material, having on opposed sides laminar resilient fingers, also electrically conducting, giving the socket a substantial appearance of a two legs fork, useful to press, for providing connection, a strip shaped conductor or blade connected, for example, to insertable devices, being said socket either of simple kind fastened to a bus-bar, operating also as a central body, or of double kind comprising a central body from which protrude in two opposed directions two laminar finger assemblies to alllow connection between conducting blades of different devices, or between the bus-bar of a control board and the blade of a device.
It is well known that, owing to ovecurrents, repelling forces are developped between the conductor inserted in the socket and the resilient fingers or jaws thereof, being said repelling forces caused by current flowing between the conductor and the fingers.
Thus it is an object of the present invention to provide connecting socket able to oppose the most the possible to overcurrents without opening, avoiding consequent overheated areas or electric arcs and possible welding between the conducting blade inserted thereinto and contacting areas in the same, reducing the total contac resistance in current flowing area between socket and conducting blade therein inserted, not opposing exagerated strength against the insertion of a blade , and eventually resulting reliable and of simple manufacture to be provided trough an automatic process.
To attain this object is taken advantage from the fact that said repelling forces are proportional to the square of the current producing them and that currents flowing in parallel conductors, even if they are each other proximate, are substantially ininfluent on said repelling forces, so that if, for example it is possible to halve the current flowing between a conductor and a finger leg by just dividing said finger in two legs, said repelling forces are reduced to about a quarter while the resilient forces due to the fingers are just halved, resulting in a higher capacity of the socket to resist to ovecurrents. Of course, this principle is exetensible in the sense that said finger can be divided in more than two parallel legs (for example three) with apparent higher advantages in term of lesser repelling forces and better resilient forces to resist thereto.
Another fact from which arises the present invention is the fact that the materials assuring the highest electric conduttivity usually do not have so good mechanical features to allow a good reaction against the above mentioned repelling forces, while the materials having sufficient mechanical features usually have poor electric conduttivity so that it is necessary to separate the current carrying members from the members providing the repelling forces.
This is obtained by simply providing the connecting socket according to the present invention with internal strips of good conductive material surrounded by external strips of a material having such mechanical features that the internal strips, resting against the external strips, receive therefrom an internally directed thrust assuring a contact with a threbetween inserted blade conductor and a reaction against the above mentioned repelling forces, characterized in that the internal condutctive strips are longitudinally shared into a plurality of substantially equal and parallel legs.
The external resilient strips resting against the internal strips are similarly shared. Further, the external resilient strips are planar obtainable from a web without any subsequent thermal treatment and, as a consequence, are of the highest manufacturing simplicity and highest operating reliability.
Particularly, said legs sharing the internal and external strips are two in number.
Alternatively, said legs are three in number.
Further alternatively, said legs are in a number hihger than three.
More particularly, said external strips are directly resting against said internal strips.
Alternatively, said external strips are resting against said internal strips through an intermediate insulating layer which electrically insulates the internal conductive strips from the resilient external strips.
According to an alternate embodiment of the present invention, just the conductive internal strips are divided in a plurality of paralllel legs, while the external strips are in one piece and resting against the internal strips through an insulating layer.
The features and the advantages of the present invention will be made more apparent from the following detailed description of embodiments thereof, just given as not limiting examples and provided with the enclosed drawings, wehrein:

figure 1 is a frontal view of a first embodiment of connecting socket, according to the present invention, of simple kind suitable to be fastened to the end of a bus-bar;
figure 2 is a lateral view of the same embodiment of figure 1;
figure 3 is a view, similar to that of figure 1, in which the socket houses a conductive blade therein inserted;
figure 4 is a lateral view of the socket shown in figure 3 housing a conductive blade;
figure 5 is a frontal view of a second embodiment of connecting socket, according to the present invention, of double insertion kind, suitable to connect two bus-bars or conducting blades and manufactured both fixed with respest to a board frame for operating as a connector between conductors of insetrable devices, and movable for operating either as a connection among bus-bars or conducting blades of a board or to fixed devices;
figure 6 is a lateral view of the same embodiment of figure 5;
figure 7 is a view, similar to that of figure 6, wherein the double socket houses two inserted conducting blades;
figure 8 is a lateral view of the socket shown in figure 7 housing two conducting blades.

Referring first to figures 1 to 4, it is seen that a simple connecting socket 10 is comprised of two lateral flanges 12a and 12b surrounding a central body 14 having shape of a flat parallelepiped of metallic electrically well conducting material, which in this specifical case is the prosecution of a bus-bar largely used in electric plants and in electric power distribution and control boards.The two lateral flanges 12a and 12b comprise two internal well conducting strips 16a and 16b, for example made of copper, externally terminated by expanded inserting and contacting areas 18a and 18b suited for assuring insertion in the socket 10 and a good electric contact with an external conductor to be inserted in said socket, two possible intermediate strips 20a and 20b of electrically insulating material and two resilient external strips 22a and 22b having the task to provide a prevailing thrusting force against the internal conducting strips 16a and 16b.
According to the invention, any internal conducting strip 16a and 16b is shared in three parallell legs 16a1, 16a2 and 16a3 (shown in figures 1 and 3) and 16b1, 16b2 and 16b3 (not shown) among which is substantially equally shared the current, ending with inserting and contacting areas, also shared, 18a1, 18a2 and 18a3, against which are obviously opposed iserting and contact areas 18b1, 18b2 and 18b3 (not shown), said strip sharing having a herebelow explained purpose.
Also the strips 20a and 20b , 22a and 22b are similarly shared, as shown by the legs 22a1, 22a2 and 22a3 depicted in figures 1 and 3, and are used to provide resilient thrust to the underlying legs 16a1, 16a2 and 16a3 of the conducting strip 16a.
Lastly, the two lateral flanges 121a and 12b are fastened around the body 14 by means of two rivets 2 and 26 strongly fastening them thereto.
As shown in the figures 3 and 4, a conducting blade 30 is inserted between the flanges 12a and 12b of the socket 10 by thrusting aside the two strip assamblies 16a, 20a, 22a on a side and 16b, 20b and 22b on the other and assuring a contac with the areas 18a and 18b, where the legs 22a1 ,22a2, 22a3 and 22b1, 22b2 22b3 of the strips 22a and 22b provide fastening thrust to the conducting strips 16a and 16b against the sides of the conducting blade 30.
Referring now to figures 5 to 8, a double insertion socket 40, according to the invention, is seen as comprising two pairs of lateral flanges 42a, 42b and 44a, 44b fastened around a central socket body 46 and made by two internal strips 48a, 48b and 50a, 50b of highly conductive material, as for example copper, surmounted by inserting and contacting areas 52a, 52b and 54a, 54b, respectively and possibly surrounded by two insulating external strips 56a, 56b and 58a, 58b having the task of electrically separate internal copper strips 48a, 48b and 50a, 52b from external resilient thrusting strips 60a, 60b and 62a, 62b, respectively, having the task to thrust against the copper strips 48a, 48b and 50a, 50b.
According to the invention, anyone of the internal strips 48a, 48b and 50a, 50b is shared in trhee legs 48a1, 48a2 48a3 and 50a1, 50a2, 50a3 (depicted in figures 5 and 7) and 48b1, 48b2, 48b3 and 50b1, 50b2, 50b3 (not shown), bearing anyone a substanially equal current share, for the herebelow disclosed purposes. Of course, also the inserting and contacting areas 52a, 52b and 54a, 54b are also shared in subareas 52a1, 52a2, 52a3 and 54a1, 54a2, 54a3 (depicted in figures 5 and 7) and in subareas 52b1, 52b2, 52b3 and 54b1, 54b2, 54b3 (not shown). Likely, the external resilient thrusting strips 60a, 60b and 62a, 62b are also shared in three legs 60a1, 60a2, 60a3 and 62a1, 62a2, 62a3 (depicted in figures 5 and 7) and 60b1, 60b2, 60b3 and 62b1, 62b2, 62b3 (not shown), correspondingly sharing the forces on the underlying conductive strips 60a, 60b and 62a, 62b.
At last, the flanges 42a, 42b and 44a, 44b are strictly fastened against the central body 46 of the socket by clinched rivets 64 and 66.
The insertion of conducting blades 70 and 72 between the flanges 60a, 60b and 62a, 62b is particularly depicted in the figures 7 and 8, where said conducting blades are shown coming into said flanges, phusing aside them and providing a good contact therewith through the inserting and contacting areas 52a, 52b and 54a, 54b.
The operation of the present invention, inferable from figures 1 to 4, being that inferable from figures 5 to 8 completely similar, is the following one:
the insertion of a conducting blade 30 into the socket 10 pushes aside the conducting strips 16a and 16b, abutting them against the external resilient strips 22a and 22b, so that the contact expansions 18a and 18b press the blade 30 assuring a good contact between the same and the socket 10.
The contact between the blade and the socket happens substantially around the inserting and contacting expansions 18a and 18b, so that in case of overcurrents repelling forces between said blade and expansions are developped at the passage points therebetween.
As depicted in figures 1 to 4, the flanges 12a and 12b of the socket 10 are anyone shared in three longitudinal parallel legs, being particularly the internal contact strips 16a and 16b shared in parallel legs 16a1, 16a2, 16a3 and 16b1, 16b2, 16b3 (not shown) surmounted by inserting and contacting expansions 18a1, 18a2, 18a3 and 18b1, 18b2, 18b3, of which only the expansions 18a1, 18a2, 18a3, are visible, abutting every leg of the internal strip 16a against a corresponding external leg 22a1, 22a2, 22a3 of external strip 22a and, abutting obviously every leg of internal strip 16b against a corresponging external leg 22b1, 22b2, 22b3 (not shown ) of external strip 22b.
The parallel legs 16a1, 16a2, 16a3 and 16b1,16b2, 16b3 of the strips 16a and 16b obviously share the currents flowing between conductive blade and socket developping at the expansions 18a1, 18a2, 18a3 and 18b1, 18b2, 18b3 repelling forces whose magfnitude is substantially a ninth (a squared thrid) of the forces developped if the internal conducting strips were not longitudinally shared, while the resilient forces due to the legs 22a1, 22a2, 22a3 and 22b1, 22b2, 22b3 of the external strips 22a and 22b reduce to just a third with apparent more favourable ratio between the repelling forces and the reactive forces due to the legs of the external strips.
What has been hereabove disclosed depictes two embodiments of the present invention given in not limitng way and those skilled in the art willbe able to devise obviously altrenate and equivalent approaches and features to be meant all here covered. For example, the external resilient strips 22a and 22b instead to be share in three legs, as here depicted, could be integral, with the provision of using the insulaitng layers 20a and 20b, supplying a higher reaction force against the repelling forces developped by the overcurrents.

Claims

Connecting socket provided with internal strips (16a, 16b) of good electrically conductive material surrounded by external strips (22a, 22b) of a material having mechanical properties so that the internal strips (16a, 16b), abutting against the external strips (22a, 22b), receive therefrom a thrust to the inside assuring contact with a conducting blade (30) inserted therebetween and a reaction against repelling forces, characterized in that the internal conductive strips (16a, 16b) are equally longitudinally shared in a plurality of substantially equal and parallel legs.
Connecting socket, as in claim 1, characterized in that also the external resilient strips (22a, 22b) abutting against the internal strips (16a, 16b) are similarly shared.
Connecting socket, as in claims 1 and 2, characterized in that siad legs, sharing the internal strips (16a, 16b) and the external ones (22a, 22b) are two in number.
Connecting socket, as in claims 1 and 2, characterized in that said legs, sharing the internal strips (16a, 16b) and the external ones (22a, 22b), are three in number.
Connecting socket, as in claims 1 and 2, characterized in that said legs, sharing both said internal and external strips are more than three in number.
Connecting socket, as in claims 1 to 5, characterized in that said external strips (22a, 22b) are directly abutting against said internal strips (16a, 16b).
Connecting socket, as in claims 1 to 5, characterized in that said external strips (22a, 22b) are abutting against said internal strips (16a, 16b) through an insulating layer (20a, 20b) which electrically insulates the conducting strips from the elastic strips.
Connecting socket, as in claim 1, characterized in that only the internal conductive strips (16a, 16b) are shared in a plurality of parallel legs, while the external strips (22a, 22b) are in one piece abutting against the internal strips through an insulating layer (20a, 20b).