WO2009036859A1

WO2009036859A1 - Electrical wire spring contact system

Info

Publication number: WO2009036859A1
Application number: PCT/EP2008/006880
Authority: WO
Inventors: Karl Heinz Arndt; Thomas Freyermuth; Artur Wiese
Original assignee: Moeller Gmbh
Priority date: 2007-09-22
Filing date: 2008-08-21
Publication date: 2009-03-26
Also published as: EP2191484A1; PL2191484T3; EP2191484B1; DE102007045432B3

Abstract

The invention relates to an electrical contact system having one input contact and at least one output contact. Said contact system comprises a contact spring (10) comprised of wire that is held centrally in the contact system by a holder element (32). Two straight-stretched contact limbs of approximately the same length spread on both sides of the holder element (32). The contact limbs span an obtuse opening angle W without applying an elastic preload. A first contact limb (14) is placed against an input contact (20) designed as a first support and a second contact limb (16) is placed against a second, insulating support (26), expanding the opening angle W and generating a preload V. At least one output contact (22, 24) is disposed adjacent to the second contact limb (16). The contact system may be designed as an open element or as a closed element or as a change-over switch. This is achieved by the arrangement of output contacts on the sides of the second contact limb.

Description

ELECTRIC WIRE SPRING CONTACT SYSTEM

The invention relates to an electrical contact system, in particular for low voltage, with an access contact and with at least one outgoing contact. It comprises a wire contact spring, which is held centrally by a holding element in the contact system. On both sides of the retaining element, two straight-extended contact legs spread out with approximately the same length. The contact legs clamp without applying an elastic bias between them an obtuse opening angle.

Electronic circuits work with low voltages and very low currents and are to get along with ever smaller power losses.

In a command device program from DE 19856678 A1 there are contact elements, with an electrical contact for higher voltages and larger currents. The contact is designed so that it can switch such voltages and currents, even with the arc occurring very often. Problems arise when using these contacts for switching very small currents and voltages. In this case, most existing dust particles or oxides formed on the contact prevent safe contact. The tension can no longer penetrate such layers. Also missing is a switching arc, which could run the contact point.

One possibility for improving the contact reliability are wire cross contacts, as proposed, for example, in DE 102004012777 B3 or in DE 7721796 U1. Here, the contact force acts only at a very small point of contact and in this way foreign layers are easier to pierce. Slip contacts rub on the pad to remove the debris or oxides, but they also create undesirable abrasion and dig into the material at one point. An improvement for the life bring here, for example, sliding contacts with a tangential contacting, as described in DE 19817796 C2 or DE 1489080 A. A combination of contact spring with pins as cross contact with tangential friction movement at the contact point can be found in the contact arrangement of an electromagnetically actuated relay according to DE 1071837 B.

Also known is a contact arrangement for low voltages with a spring wire, which is wound in less than one turn around a first contact pin and extended to rest against a first contact pin by a first wire leg (US 3,946,185). The spring wire has a second, fixed wire leg for elastically bringing the first wire leg into contact with a second contact pin. A third contact pin is near the spring wire and on the second Contact pin provided opposite side, being brought by pressure on the spring wire at a position between the first and the second contact pin of the spring wire in elastic contact with the third contact pin. The contact system is only designed for very small switching strokes. For use in switches in which a large switching stroke, including a corresponding Durchhubs is desired, the contact system is not suitable because the spring wire with less than a number of turns on the support member will be claimed beyond its elastic limit, and thus would have a very limited life ,

It is the object of the invention to specify an electrical contact system, in particular for very low voltages and low current, which is robust and with which a long service life can be achieved.

The solution of the problem can be found in the main claim. Advantageous embodiments are formulated in subclaims.

The core of the invention is formed in a special shape and storage contact spring.

The contact spring of the contact system is held centrally by a holding element in the contact system. On both sides of the holding element, two, straight-stretched contact legs spread out with approximately the same length, wherein the contact legs clamp between them an obtuse opening angle without applying a resilient bias. A first contact leg is against a trained as the first support access contact and a second contact leg is applied against a second insulating support with increasing the Öffhungswinkels and generating a bias voltage. Adjacent to the second contact leg at least one outgoing contact is arranged. The contact system can be designed as an opener or as normally open or as a changeover switch. This is achieved by the arrangement of outgoing contacts on the side of the second contact leg.

The alternative training can be:

(1) Normally closed contact: The first outgoing contact lies on the side of the second contact leg facing the retaining element and is contacted by the second contact leg when the retaining element is at rest.

(2) Normally open contact: A second outgoing contact lies on the side of the second contact leg facing away from the holding element and is only touched by the second contact leg when the holding element is actuated.

(3) Changer: There is both a first outgoing contact and a second outgoing contact.

Preferably, the arrangement according to the invention is used for the low-current range, where it it is important to reliably switch small voltages and small currents over many load cycles. Investigations of the arrangement have shown that the contact system reaches a contact reliability of well over 1 million.

The contact legs should preferably be of the same length so that they come symmetrically to the plant to the associated contacts. Both contact legs are brought to the deflection and thereby released from contact and brought into contact with another contact.

The contact legs are each fixed to a support bearing, one of which is provided as a first outgoing contact and the switching positions are achieved by changing the opposite contact of the first outgoing contact leg of the contact spring between an opening outgoing contact and a closing outgoing contact.

Upon actuation of the actuating tappet, one contact leg of the contact spring always bears on one pole contact pin (the "access contact") and the other contact leg is fixed to a support bearing (for example: a nose or projection in the plastic housing) an NC contact pin and a NO contact pin moves.

The holding element is designed as a perpendicular projecting from the actuator pin or pin. The contact spring is wound around the perpendicular projecting from the actuating element (actuating plunger) pins with at least one turn. The holder of the contact spring on the actuating element is in the form of a pin, such that slipping of the contact spring is prevented by the actuating element. The installation of the contact spring is done with bias. The bias and the restoring force generated during actuation effect a positive pressing of the spring coils on one side of the pin. The number of turns together with the spring characteristic of the spring wire determines the spring constant of the contact spring. Due to the structural design and the appropriate material selection, the required contact force can be securely applied to each contact points with the contact spring. Furthermore, with the contact spring and a secure through-stroke of the actuating plunger are executed.

Due to the linear movement of the actuating plunger with a journal bearing of the contact spring coils, the two contact legs of the contact spring have a tangential friction and sliding movement on the cylinder outer surface of the fixed contact pins. Dirt particles or oxides are removed at the contact points by the movement; There is a self-cleaning of the respective contact points.

The mechanical, constructive and material training of the contact system should preferably be such that the largest possible stroke (> 5 mm) on the actuating element (actuating tappet) and Hubuntersetzung the change-over contact is present.

By a positive retention of the contact spring on the actuating plunger, the contact spring also provides the return force for the actuating plunger. Another element for returning the actuating plunger to its home position is not necessary.

Preferably, the material of the contact spring is spring steel, which may have a noble metal coating. The spring steel can continue to be designed as polished, stainless steel spring steel. Its coating may be made of precious metal (e.g., gold or rhodium).

The contacts, or the pins should be made of conductive material, such as pins made of wire, carbon fibers, graphite, graphite with Cu impregnation, silver or a silver alloy. Metallic contacts may be provided with a coating of nickel (with good corrosion resistance). Metallic outgoing contacts can be soldered on or in the wiring plane, whereas carbon contacts are incorporated with a solderless fastening technique. The latter can be done by pressing into a conductive foil and additionally secured with conductive adhesive or conductive ink.

The material pairings between contact points on the contact spring and the respective associated contacts can be chosen so that existing thermal stresses are compensated. Here are two electrically in-line, identically constructed, but mirror-symmetrical contact points for a switch (per NC / each NO) used. The thermoelectric voltages are compensated. A different material pairing usually has better friction coefficients and sliding properties.

At least one contact leg can be extended beyond the distance between the holding element and the support or contact point addition. The protruding extension is bent into a U and bent back parallel to the contact leg. Thus, at least one contact leg is formed as a double, juxtaposed spring wire. Due to the doubling of the at least one contact leg, a double contact (also called H contact) arises at the contact leg associated with the output leg. The described design has the advantage that you get a double contact system with quasi double contact safety.

The contacts of the assembly are formed as pins and fixed on a mounting or wiring plane. The contacts may be soldered in the wiring plane or otherwise secured there (eg, by solderless attachment technique). The contact system can be doubled in an electrical switch housing. In this case, a first contact system can be arranged above the fastening plane and a second contact system can be arranged below the fastening plane. On the wiring or mounting level, an electrical connection can be made with electronics also arranged there with a printed circuit board or the MID technology.

A double trained contact system may be provided with an electronic control such that via a mutual control of the pole pins, once for the first contact system and the other time for the second contact system, is detected and controlled by the electronics, which of the two actuating tappet straight is pressed.

Such a changeover switch offers the advantage of additional query security and error detection.

Embodiments of the invention are shown in several figures, which show in detail:

1 side view and top view of a contact system,

Fig. 2 is a plan view of a contact system with U-shaped bent contact legs and Fig. 3 A and 3B two contact systems on a wiring level.

In Fig. 1 side view and top view are shown on a contact system, which works as a changeover switch. On an attachment or wiring plane 51, an access contact 20 and two outgoing contacts 22, 24 are arranged. As solid contacts serve (in the form of contact pins) simple round wires (or rods). The moving contact is formed by the contact spring 10 with its two straight-extended contact legs 14, 16. Contact pins and contact spring are arranged at an angle of 90 degrees to each other. The contact spring is held centrally by a holding member 32 having a plurality of turns, which is arranged on an actuating plunger 30 as a vertically projecting pin. The contact legs 14, 16 spread apart on either side of the support member 32 with approximately the same length, wherein the contact legs 14, 16 span without applying an elastic bias voltage V between them a large obtuse opening angle W. Upon actuation of the actuating plunger 30, the contact legs are pushed beyond the angle of 180 ° addition. As can be seen from the figure, the contact system also allows a certain amount of movement of the contact movement.

The first contact leg 14 is against the access contact 20 and the second contact leg 16 is applied against the insulating support 26 by increasing the opening angle W. The support 26 may be formed as a housing projection or as a round pin. First 22 and second outgoing contact 24 are disposed in the vicinity of the second contact leg 16, and come into alternation with the contact leg 16 in contact when the actuating plunger 30 is activated.

In the right part of the upper part of the figure, the positions of the contacts 22 and 24 and their distances X, Y, Z are indicated. By certain positioning of the contacts 22 and 24 to each other and with respect to the position of the holding member 32, we defined the deflection of the contact leg 16. Furthermore, a suitable switching path and a desired lift of the contact system can thereby be determined.

In the lower part of Figure 1, the current is visible. By switching the contact system, a first circuit can be opened and a second circuit closed.

In the figure 1 is not shown that the contact system - by omitting the contact 24 - even a departure contact 22 may have. In this case, depending on the position of the outgoing contact 22 - the contact system is to be regarded as a normally closed or normally open contact.

The contact system is designed as a normally closed contact, if an outgoing contact (for example 22) lies on the side of the second contact leg 16 facing the holding element 32 and is touched by the second contact leg 16 in the rest position of the holding element 32. The contact system is designed as a make contact if a feeder contact (for example 24) lies on the side of the second contact leg 16 facing away from the holding element 32 and is not touched by the second contact leg 16 until the holding element 32 is actuated.

In Fig. 2, the contact legs 14 and 16 have a modified form. Both contact legs are extended beyond the distance between the holding element and the support or contact point addition. The protruding extension is bent to a U and bent back parallel to the contact leg. Each contact (20, 22, 24) is thus contacted twice by the U-shaped contact legs (14 'and 16'). There is a double contact (also called H contact).

In the two subfigures 3 A and 3 B two contact systems are each attached to a wiring plane (51, 51 '). The wiring plane may (as in FIG. 1) be a continuous plane or as in FIGS. 3A and 3B. The training depends on the structure of the switch housing, which is not shown in detail. The contact systems are operated by separate actuators (32, 32 ') and each have a contact spring 10 and 40. The contacts are soldered in the wiring plane, wherein in the upper part of the figure, the contact pins once to the front of the wiring level 51 protrude and the contact pins of the second contact system are formed on the back of the wiring plane 51. The contacts 22 and 24 may be at the same electrical potential, so be guided solidly through the wiring plane 51 therethrough. The access contact on the front side (20) alone is electrically separated from the access contact (20 ') on the rear side of the wiring plane 51. The contact pins for NC (eg 22) and NO (eg 24) are used by both Kontaktfedem (10, 40) as a counter-contact, the two pole pins (20 and 20 ') contact only once the contact spring in the first contact system and on the other hand, the contact spring in the second contact system housing.

In the lower part figure 3B, the contact systems are on the same side of the wiring plane 51 '. The details and reference numerals of the two sub-figures 3A, 3B correspond to the previously discussed figures, so that these details will not be described repeatedly.

About a mutual control of the pole pins of the two contact systems, once for the one and the other time for the second changeover contact, an electronics can be used for monitoring, which checks which of the two plungers has just been operated and which not. The changer offers the advantage of an additional query security of the plunger position. An electronic system can evaluate both signals and can give a message as to whether the plunger has been pressed or whether a contact error has occurred.

At the wiring level, the electronics of the contact systems can continue to be integrated. This is immediately obvious, since small electronic circuits suitable for low-voltage applications can be applied and integrated by means of MID technology or in the form of a printed circuit board. For the integration of the electronics can contribute further, if in the wiring level LED displays (for switch positions) and plugs for electronic connections, for example, as BUS contacts are additionally integrated.

reference numeral

10 contact spring (of a first contact system)

12 turns

14 first contact legs

16 second contact legs

14 ', 16' contact leg U-shape

20 access contact (as a support bearing and pole pin)

22 first outgoing contact

24 24 'second outgoing contact

26 insulating support

30 actuator / plunger (of a first contact system)

32 holding element (of a first contact system)

40 contact spring (of a second contact system)

42, 44 contact legs of the contact spring of the second contact system

46 actuator / plunger (of a second contact system)

48 holding element (of a second contact system)

51, 51 'mounting plane

W opening angle

V bias

Claims

claims

1. An electrical contact system, in particular for low voltage, with an access contact and with at least one outgoing contact comprising a wire made of contact spring (10) which is held centrally by a holding element (32) in the contact system, and on both sides of the holding element (32) two Pry contact limbs (14, 16) with approximately the same length, wherein the contact legs (14, 16) without an elastic bias voltage (V) between them an obtuse Öffhungswinkel (W) span, with a first contact leg (14) against a first support formed access contact (20) and the second contact leg (16) against a second insulating support (26) are increased by increasing the Öffhungswinkels (W) are applied, and adjacent to the second contact legs (16) a first outgoing contact (22) is arranged and the contact system as Opener is formed, characterized in that the first outgoing contact (22) on the said holding element (32) facing side d it is the second contact leg (16) and at rest position of the holding element (32) by the second contact leg (16) is touched, or the contact system is designed as a closer, characterized in that a second outgoing contact (24) on the holding element (32) facing away from the second contact leg (16) and is touched only upon actuation of the holding element (32) from the second contact leg (16).

2. Contact system according to claim 1, characterized in that the contact system is designed both as normally open and as normally closed, characterized in that the first outgoing contact (22) on the holding element (32) facing side of the second contact leg (16) and at rest of the holding element (32) is touched by the second contact leg (16) and that the second outgoing contact (24) lies on the side of the second contact leg (16) facing away from the holding element (32) and is actuated by the second contact leg (16) when the holding element (32) is actuated ) is touched.

3. Contact system according to one of claims 1 or 2, characterized in that the holding element (32) on a linearly movable, the bias voltage (V) increasing actuator (30) is mounted,

4. Contact system according to claim 3, characterized in that the holding element (32) as perpendicular from the actuating element (30) projecting pin (32) is formed.

5. Contact system according to one of the preceding claims, characterized in that the contact spring (10) with at least one turn around the holding element (32) is guided around.

6. Contact system according to one of the preceding claims, characterized in that the material of the contact spring (30) is spring steel and has a noble metal coating.

7. Contact system according to one of the preceding claims, characterized in that the material pairings between contact points on the contact spring (10) and the respectively associated outgoing contacts (22, 24) are pairwise chosen so that resulting thermal stresses are compensated.

8. Contact system according to one of the preceding claims, characterized in that at least one contact leg (32) of the contact spring is bent to a U.

9. Contact system according to one of the preceding claims, characterized in that the contacts (22, 24, 24 ') formed as pins and on a mounting plane (51) are fixed, and at least one contact system in the mounting plane (51) is arranged.

10. Contact system according to claim 10, characterized in that a first contact system on the front of the mounting plane (51, 51 ') and a second contact system on the back of the mounting plane (51, 51') is arranged.

11. Contact system according to one of claims 1 to 9, characterized in that two contact systems on one side of the mounting plane (51, 51 ') are arranged.

12. Contact system according to one of the preceding claims, characterized in that on the mounting plane (51) an electrical connection with a likewise arranged there electronics with a circuit board or the MID technology.