EP1579535A1

EP1579535A1 - Connection device including a contact surrounded by a spring

Info

Publication number: EP1579535A1
Application number: EP03790962A
Authority: EP
Inventors: André Defrasne; Marc Poulet
Original assignee: FCI SA; Framatome Connectors International SAS
Current assignee: FCI SA
Priority date: 2002-08-27
Filing date: 2003-08-12
Publication date: 2005-09-28
Also published as: AU2003262572A1; FR2844105B1; FR2844105A1; CN1685572A; WO2004021521A1

Abstract

Connection device (1) including a double contact (2) mounted on a busbar, this double contact including at least one upper contact tine (5) and one lower contact tine (6) to come into contact on each side of a flat contact plug (26). Contact tines are flexible and the device includes a spring (13) to promote the return of these tines to their rest position when they are subjected to stresses during connecting or disconnecting operations with the contact plug. The spring is inserted in a slot (14) formed in each of the tines, the slot being part of the means for retaining the spring on the tines.

Description

CONNECTION DEVICE INCLUDING A CONTACT SURROUNDED

BY A SPRING

The object of the present invention is a connection device including a contact surrounded by a spring, and designed to be mounted on devices called busbars by those skilled in the art. It is used particularly in the domain of connections to be realized on electrical distribution systems whose purpose is to transmit high currents in "busbar" systems. The object of the invention is to suggest a connection device that allows a reliable connection to be assured with a flat contact plug complementary to the device, free ends intended to come into contact elastically with the contact plug being maintained in position by means of a spring. The advantage of the invention is that it suggests a spring that is easy to construct and easy to mount on the connection device.

Busbars equipped with connectors that are arranged side by side on the busbar belong to the state of the art. For example, these connectors form clips to receive a contact plug for connection with the busbar. In this case the connector includes two cut out and pre-tensioned metallic tines. These two tines are attached to a first part which is in contact with the busbar. In a second part, the two tines form free ends and are pre-tensioned and spaced with respect to one another to form the opening of a clip. When a contact plug is inserted between these two free ends, they separate due to the presence of the contact plug around which they are pre-tensioned. They ensure contact with a pinching action.

The use of such connectors in conjunction with busbars to transmit high intensity currents is known in the art. In particular, they are used in heavy current distribution units. In such units, it is useful in particular to be able to connect and disconnect certain of the connectors. The connectors that are placed under stress most often suffer wear by distortion. Indeed, because the free ends are forced apart regularly, they gradually lose their pre-tensioned shape, which may lead to situations in which the clip no longer comes into contact with the contact plug inserted therein.

Moreover, given that the connections that are made inside this box must be made quickly, they are often made without a great deal of care. As a result, when the contact plug is inserted incorrectly between the two flexible tines, the tines may be damaged very quickly and lose their pre-tensioned shape.

Because of this situation it is known in the state of the art to provide walls that limit the separation of the free ends of the tines. But the existence of these walls and the means by which they are retained about the flexible tines without impairing the electrical connection poses a problem. In the state of the art, a complex device including an attachment collar is provided. This attachment collar encloses the free ends of the flexible tines over their entire external periphery, and this attachment collar is itself connected to the busbar.

The object of the invention is to provide a solution to the problem described in the aforegoing by suggesting a means for maintaining the space between the two flexible tines that does not impair the electrical connection and that can be mounted simply on these flexible tines. According to the invention, the flexible tines are furnished with a slot into which a spring device may be inserted. This spring device serves as a counter spring. In fact, by virtue of its shape, this device acts to counter the spreading forces of the two flexible tines when a contact plug is inserted between these two flexible tines. Otherwise, even without a contact plug inserted between the two flexible tines, the spring device serves to maintain the two flexible tines in their pre-tensioned positions. Effectively, the spring device has a U-shape wherein each of the two legs of the U surrounds a flexible tine.

The advantage of the spring according to the invention is that it is retained in a slot formed in the flexible tines. It is supported by each of the flexible tines. For this purpose, each of the two flexible tines is furnished with a slot to receive the respective leg of the U formed by the spring.

The object of the invention is a connection device including a double contact, the double contact forming a U-shaped elastic connection clip, the free ends of this double contact extending on either side to form the legs of the U, the free ends are pre-tensioned and assure a clamped contact with a contact plug designed to cooperate with the connection device, the contact plug being inserted between at least one lower free end and at least an upper free end, characterized in that it includes a U-shaped spring to reinforce an elastic return of the free ends toward their pre-tensioned position, this spring being inserted in a slot formed in the lower and upper free ends. The invention will be better understood with reference to the following description and the associated figures. These are included purely for purposes of illustration and in no way limit the scope of the invention. The figures show:

- Figure 1 : an exploded top view of a connection device, according to the invention mounted on a busbar ;

- Figure 2 : a top view of the device, according to the invention ;

- Figure 3 : a top view of a spring, according to a first embodiment of the invention ;

- Figure 4 : a top view of a spring, according to a second embodiment of the invention ;

- Figure 5 : a sectional view of a device according to the invention during mounting of the spring, according to the first embodiment ;

- Figure 6 : a sectional view of a device according to the invention during mounting of the spring, according to the second embodiment ;

- Figure 7 : a general view of the device, according to the second embodiment of the invention to be connected with a contact plug.

Figure 1 shows a connection device 1 according to the invention. This device 1 includes a contact 2 designed to be mounted on a busbar 3. Busbar 3 preferably receives several contacts such as 2 all fixed in the same manner to busbar 3. Busbar 3 is for example rectangular in shape, and contacts such as 2 are connected along the long edge of this rectangle. Busbar 3 is for example made from solid copper and obtained as a cut out from a copper plate, which is then chemically etched.

Busbar 3 may be connected inside a box for power current distribution. For this purpose it includes a wiring surface 4. This wiring surface 4 is obtained by cutting out from a metallic sheet and bending to form at least two 90° angles so as to present plate 3 parallel to a bottom of the box to which it is fastened.

Contact 2 is a double contact, it includes at least one upper flexible tine 5, and at least one lower flexible tine 6. In the example shown in Figure 2, flexible tines 5 and 6 are each arranged facing one another. They have an opening 9 at each of their free ends 7 and 8. This opening 9 is intended to receive a contact plug (not shown) that is designed to function with device 1. This contact plug has for example an elongated flat shape, so that upon its insertion into opening 9, free end 7 comes into contact with an upper face of the contact plug, while free end 8 comes into contact with the lower face of this contact plug. Double contact 2 is formed by the presence of upper free end 7 and lower free end 8.

The flexible tines are obtained for example by cutting out from a metal plate and then by bending this cut out. In this case, upper tine 5 includes a first portion 10 that is to be fastened to busbar 3, this first portion is extended by a tongue 11 , which is longer than it is wide, thus lending it a certain flexibility. This tongue 11 is bent so that it has a concave shape when seen in cross-section. The bent, or pre-tensioned, portion of this tongue 11 forms upper free end 7.

Similarly, lower tine 6 includes a first portion 10' like 10, which is designed to be fixed to busbar 3, and a tongue 11' having a concave shape. Tongue 11 ' has forms example a symmetrical shape with tongue 1 1 about a plane of symmetry 12. Tongue 11' then also has a concave shape, so that when first portions 10' and 10 are attached between them, tongues 11' are distributed symmetrically on either side of the plane of symmetry 12. Tongues 11 and 11' are not in contact with one another, they are free. The pre-tensioned portion of tongue 1 1' thus forms lower free end 8.

Tongues 11 and 11' extend overall parallel to the plane of symmetry 12, and this plane 12 orthogonally intersects the opening 9 that is formed between the two free ends 7 and 8. They form a clip which may be elastically deformed by the insertion of the contact plug.

More particularly, the shape of the free ends is such that each free end presents a first bend level with opening 9 to flare edges 105 and 106 away from opening 9. These bends also enable the flexible tines to be brought closer to one another and to afford an opening 9 where the minimum distance between the two flexible tines 5 and 6 is less than an average thickness of the contact plug intended to be inserted therein.

When the contact plug is inserted into opening 9, the flexible tines are under stress, and maintaining this stress, as well as the numerous acts of connecting and disconnecting may result in the tines becoming deformed and no longer able to return to their rest position in which the separation of the two tines is significantly smaller than the average thickness of a standard contact plug. For this purpose device 1 according to the invention includes a spring 13.

This spring 13 encloses the flexible tines at least in the area of their concave portions, and forces them to return to their rest position when no contact plug is inserted between the two. On the other hand, the presence of spring 13 increases the contact pressure of these flexible tines when a contact plug is inserted therebetween.

Spring 13 is inserted into a slot 14 formed in each of the flexible tines. Specifically, upper tine 5 includes a slot 14' and lower tine 6 also includes a slot 14". These slots 14' and 14" open into the gap formed between the two tines. This spring 13 has a U-shape, so that it has two legs 15 and 16 respectively. Spring 13 preferably has an axis of symmetry, so that it may be inserted into slot 14 for either one of the two legs 15 or 16. In fact, the slot 14 is barely wide enough to accommodate spring 13. The extremities of legs 15 and 16 are supported respectively against the external faces 17 and 18 of flexible tines 5 and 6.

According to a first embodiment, spring 13 is shaped like a horseshoe and is cut out from a metallic plate in the U-shape. Slot 14 is then scarcely wider than the thickness of the plate from which spring 13 was cut. In order to ensure that spring 13 retains this shape, slots 14' and 14" are each formed only in the upper faces 17 and 18. They do not open out in the area of flared edges 105 and 106, nor opposite opening 9. Spring 13 is thus inserted in slot 14 from one of the external faces. In order to be retained in the slot, each of legs 15 and 16 includes a spur 19 and 20. Spurs 19 and 20 are disposed opposite one another and are designed to cooperate with the front edges of slots 14' and 14" respectively.

To install the spring 13 produced according to the first embodiment, spring 13 is arranged vertically above one of the external faces, for example external face 17. The U cavity 21 is arranged so that it is farthest from opening 9. Legs 15 and 16 are introduced into slot 14 while keeping the cavity 21 outside the slot. Legs 15 and 16 are placed such that the two spurs are supported against the edges of slots 14' and 14" respectively. The effect is to create edges defining the small width of the slot and arranged as closely as possible to opening 9. In figure 2 these edges are not shown. Finally, to complete the installation of the horseshoe-shaped spring 13, a force is applied on a narrow edge of the cavity 21 that protrudes beyond external face 17 to impart to it a rotating movement. When the position of the legs of the U are coincident with the internal walls of the gap formed between tines 5 and 6, the spring reaches a stable, balanced position. Since spring 13 is slightly longer than the length of slot 14, it then remains in its equilibrium position.

A U-shaped spring of such kind provides a force limiting the excessive spreading of tines 5 and 6 which is a function of the shape of cavity 21 and its degree of internal curvature.

According to a second embodiment, spring 13 also forms a plier. For this purpose it is furnished with an oblong stem 22, from which extend two branches 23 and 24, disposed opposite one another. This spring 13 is obtained by cutting out from a metallic plate, roughly in an X shape. Then, the X shaped piece is bent so that the centre of intersection of the two arms of the X forms stem 22. The branches of the X are folded together in pairs to form the two branches 23 and 24.

In this variant also, spring 13 may have a plane of symmetry, so that it is possible to insert it into slot 14 regardless of whether the slot is in the upper or lower face. Then, as is shown in Figure 6, spring 13 according to this embodiment is inserted starting from opening 9. In this case, unlike the first embodiment, slots 14' and 14" open into the flared edges 105 and 106, to allow stem 22 to penetrate to the bottom of the gap formed between the two tines 5 and 6.

On the side of stem 22, branches 23 and 24 are separated by a distance substantially larger than opening 9. This means that when spring 13 is shifted toward the bottom of the gap, branches 23 and 24 each pass above the external faces. In this case, upper branch 23 extends over external face 17, while lower branch 24 extends over external face 18.

Additionally, branches 23 and 24 are each curved such that the distance between these two branches decreases with distance from the stem 22. More particularly, the branches are bent so that they enclose the concave shapes of tines 5 and 6. Accordingly, when spring 13 is displaced until stem 22 abuts the bottom of this slot 14, the bent branches progressively constrain the tines by exerting pressure on their external faces. But when stem 22 reaches its abutted position, branches 23 and 24 no longer constrain tines 5 and 6 because they are then placed in a position wherein they enclose tines 5 and 6 without exerting any force. Branches 23 and 24 are also pre- tensioned and they promote the return of tines 5 and 6 to their rest position.

In a preferred embodiment, slot 14 is created in the middle of each of external faces 17 and 18. Specifically, slot 14' is formed in the middle of the upper external face, and slot 14" is formed in the middle of the lower external face. Slots 14' and 14" are arranged about a plane of symmetry 25 of free ends 17 and 18. This plane of symmetry is orthogonal to plane 12, furthermore it extends parallel to the main extension axis of tines 5 and 6. Effectively, plane of symmetry 25 is parallel to the longest edges of these tines.

Figure 7 is a general illustration in which connection device 1 with its double contact 2, according to the second embodiment, is introduced to come into contact on both sides with a flat contact plug 26.

Claims

1 - Connection device (1) including a double contact (2), the double contact forming a U-shaped elastic connection clip, free ends (7, 8) of this double contact extend on both sides to form legs (5, 6) of the U, the free ends are pre-tensioned and ensure a contact by pinching a contact plug intended to cooperate with the connection device, the contact plug being inserted between at least one lower free end (8) and at least one upper free end (7), characterized in that it includes a U-shaped spring (13) to promote an elastic return of the free ends to their pre-tensioned positions, this spring being inserted in a slot (14) formed in the lower and upper free ends.

2 - Device according to the claim 1 , characterized in that the U- shaped spring is supported against the external faces (17, 18) of the free ends, allowing the internal faces of these free ends to come into contact with the contact plug.

3 - Device according to either of claims 1 to 2, characterized in that the free ends and the slots (14', 14") formed in each of them are symmetrical to one another.

4 - Device according to claim 3, characterized in that the slot is formed about a plane of symmetry (25) of the free ends.

5 - Device according to any of claims 1 to 4, characterized in that the spring is cut out in the U-shape from a metallic plate, and in that it includes spurs (19, 20) to cooperate with the lower and upper edges of the slot.

6 - Device according to claim 5, characterized in that the spring is slightly longer than the length of the slot, and in that it is inserted from an external face of the free ends.

7 - Device according to any of claims 1 to 6, characterized in that the spring is cut out from a metallic plate and bent so as to present a stem (22) for insertion in the slot, this stem including an upper branch (23) and a lower branch (24), each branch respectively coming into contact with the external faces of the free ends. 8 - Device according to claim 7, characterized in that it is inserted from a front opening (9) in the free ends, the contact plug also being inserted via this opening between the two free ends.

9 - Device according to any of claims 1 to 8, characterized in that it is mounted on a busbar (3).