WO2006085829A1

WO2006085829A1 - Electric automatic switch

Info

Publication number: WO2006085829A1
Application number: PCT/SI2005/000004
Authority: WO
Inventors: Matija Strehar; Miran Dolinsek; Domen Janc
Original assignee: ETI Elektroelement dd
Current assignee: ETI Elektroelement dd
Priority date: 2005-02-09
Filing date: 2005-02-09
Publication date: 2006-08-17
Anticipated expiration: 2007-08-09

Abstract

A low-loss electric automatic switch for the protection of electric current consumer devices and electric circuits preferably corresponding to size 1 according to DIN 43880 and has a module width 18 mm intended to be built in as a selective main switch. The switch of the invention is conceived in a way that it contains a magnetic yoke (4), in which a leading bushing (5) is positioned between both free ends of the magnet yoke (4), whereas a coil (6) is positioned on the bushing (5) and at one end of the bushing (5) there is a core (7), and at the opposite end of it there is a large anchor (8) and between the core (7) and the large anchor (8) and within the large anchor (8) there is a small anchor (9), whereas in the core (7) there is a bar (10) that moves along its axle anf leans at one end on the small anchor (9) and at the other freely protrudes from the magnet yoke (4); furthermore in the aera between the clamp (2) and the bar (10) there is a support (16), whereby the three-position converter (18) is fastened via two springs (19) and (20) on a swing hinge (21); and on the magnet yoke (4) in the vicinity of the arc bus (13) there is another contact (15), which is electrically conductively connected with the magnet yoke (4).

Description

ELECTRIC AUTOMATIC SWITCH

Subject of Invention

The subject of the invention is a low-loss electric automatic switch for the protection of electric current consumer devices and electric circuits. The switch of the invention is preferably intended as a switch corresponding to size 1 according to DESf 43880 and has a module width 18 mm; it has low own power loss and assures selectivity.

Technical Problem

The technical problem solved by the invention is how to conceive such low-loss electric automatic switch for the protection of electric current consumer devices and electric circuits that will also be adequate for large-volume production in the sense that the structure itself would be such to define when und under what switch load the switch will turn off the circuit, whereby the switch should be responsive to said parameters within a relatively small tolerance field.

Prior Art

All prior art electric switches of this type are based on series switching-on of a short-circuit converter - over-current actuator and the arrangement of contacts as depicted in the German patent application No. 45892 of March 22, 1928.

All these designs share an over-current actuator that uses circuit heat to heat a thermo-mechanical converter at a certain operation and in case of failure at an increased current the protect switch device interrupts the protected electric circuit. A characteristic of all these devices lies in that over the period of protection the selected circuits consume approximately 1 %o of the power needed for protection.

High consumption is expensive on one hand and over a long period of time the costs are not neglectable, and on the other this l%o of consumed power transforms into heat, which has a detrimental effect on the switch and the neighbouring switches, because the preferred installation of such switch is in a series of several switches of this type. Operation of said switches at an increased temperature changes the above-mentioned operation characteristics. A further characteristic of these switches is their possibility of switch-off even in a subsequent short-current surge, e.g. when a current consumer device like a lamp, electric motor and similar is switched on, which is, however, not foreseen.

The switches of the German patent applications DE 3840482 and DE 4118377 are not capable of doing away with this problem.

The inventor is furthermore acquainted with a switch, in which a thermo- mechanical converter is replaced by a megneto-thermic converter. Such variant substantially contributes to a lower consumption of the switch and consequently to a lower increase of the environmental temperature. The solution is conceived in the following way: one anchor attracted by a coil is adjustable by an adjusting screw in order to assure the nominal parameters of the switch to be kept within the expected tolerance field. It could cause a technological and finally a price problem in large- volume production.

The goal of the invention was therefore to conceive substantially the same switch with a magneto-thermic converter and its favourable properties as to low own consumption and essentially low harmful heating of the environment and insensitivity to current surges, and yet such switch that will be adequate for large- volume production without a need to determine parameters for each switch separately.

Solution to the Technical Problem

The described technical problem is solved by an electric automatic switch of the invention, the essential characteristic of which lies in that a magneto-thermic converter is conceived of two anchors aligned on the same axle, said anchors having various characterisics. Both anchors act on the same bar depending on the status of the current in the protected circuit and its characteristic. Each anchor determines a certain axial movement of the bar at various currents and their duration. The bar acts on a three-position switch defining various currents within the switch at various currents. The coil in each type of the switch is implemented with respect to the foreseen possible electric currents within a secured conduit and switch-off times. Dimensioning of coils in large- volume production achieves nominal parameters of the switch in acceptable tolerance. Calibration of each product separately is superfluous.

The above-mentioned solution diminishes the number of constituent parts, which shortens the assembly time, and what's more all parts are conceived in a way that no adaptation of parts is needed after the assembly of the switch in order to reach the nominal parameters of the product.

The essence of the invention will now be described in more detail in the continuation by a description of an embodiment and the enclosed drawing, in which

Fig. 1 shows an electric wiring diagram of the switch of the invention with an indication of three positions of the converter, Fig. 2 shows a switch of the invention in longitudinal cross-section and in the mode when the circuit operates without interruptions and when the three- position converter on Fig. 1 is in position 2;

Fig. 3 shows a switch of the invention in longitudinal cross-section and in the mode when the direct section of the protected circuit in the switch is interrupted due to a trouble and by preserving a parallel circuit through a bimetal and the three-position converter on Fig. 1 is in position 3;

Fig. 4 shows a switch of the invention in longitudinal cross-section and in the mode of simultaneous interruption of direct section of protected circuit in a switch and parallel circuit due to a moment surge of potent electric current in protected circuit and when the three-switch converter on Fig. 1 is in position 3; and

Fig. 5 shows a switch of the invention in longitudinal cross-section and in the mode of manual switch-off by a simultaneous interruption of direct section of the protected circuit in the switch and parallel circuit due to the appearance of high electric current over a long period of time and when the three-position switch on Fig. 1 is in position 3 and the manual lever in switch-off mode.

The electric automatic switch consists of an electrically nonconductive housing 1, preferably of any of standard housings allowing an arrangement of switches in a battery on the collecting bus, which is not shown on figures, or in another way.

At one end of the housing there is a connecting clamp 2 for the supply connection of the electric circuit, which is intended for protection. At the opposite end of the housing 1 there is a connecting clamp 3, preferably the same as the clamp 2 for the discharge connection of the electric circuit, which is intended for protection. The housing 1 houses a magnetic yoke 4, preferably in the shape of a square U, in which a leading bushing 5 is positioned between both free ends of the magnet yoke 4. A coil 6 is positioned on the bushing 5. At one end of the bushing 5 there is a core 7, and at the opposite end of it there is a large anchor 8 positioned in a way to move along the axle. Between the core 7 and the large anchor 8 and within the large anchor 8 there is a small anchor 9 that moves along its axle. In the core 7 there is a bar 10 that moves along its axle and leans at one end on the small anchor and at the other freely protrudes from the magnet yoke 4.

In the housing there is further a first contact 11 electrically connected with a coil 6 and simultaneously with a resistor 12. The resistor 12 is preferably conceived as electrically conductive, several times as a meander twisted ribbon to reach the expected resistance. Means 13 are electrically connected to the resistor 12, said means deforming their shape when an increased current flows through them. The means 13 are preferably a bimetal, they can also be a memory element and the like. The means 13 are preferably shaped as the letter U, so that one free end of one leg is electrically connected with the resistor 12 as already mentioned and another free end of the second leg is connected with the magnet yoke 4 via a current line.

Furthermore the housing comprises preferably near the magnet yoke 4 and at the opposite side of the resistor 12 an arc bus 14 with a fire extinguishing chamber 14a, so that the arc bus 14 is electrically connected with the clamp 2. Between the bus 14 and the chamber 14a there is an electrically nonconductive gap during regular operation of the switch.

On the magnet yoke 4 in the vicinity of the fire extinghishing chamber 14a there is another contact 15, which is electrically conductively connected with the magnet yoke 4. Between the clamp 2 and the bar 10 in the housing 1 there is a known triggering locking mechanism 16a, on which there is a support 16 rotatable around its axle 17, preferably arranged between the bar 10 and the contact 11. The three-position converter 18 is fastened via a spring 19 on a swing hinge 21. The converter 18 with its contact 22 resistant to burning off can be electrically conductively connected to a second contact 15 and with its contact 23 electrically conductively with its contact 11. The converter 18 is moreover uninterruptedly connected via a guide 24, preferably a cord, with the clamp 2.

The converter 18, as already mentioned, is fastened with a spring 19 engaging with the converter 18 in the area of the contact 22, in the area of the opposite end, the converter 18 is pivoted in a swing hinge 21 preferably conceived as a bar element having hinge extensions, of which one is intended for fitting into the housing 1 and another into the converter 18.

In the vicinity of fastening to the spring 19 the support 16 is fastened to the spring 20 fixed with its other end to the housing 1. Both springs 19 and 20 provide for the converter 18 to lean against both contacts 11 and 15.

One of the parts of the switch mechanism contains a tooth abutting the transversal leg of the means 13, preferably bimetal. When bent, it turns the means 13 at an increased electric current flowing through it, presses on the tooth 25 thus releasing the entire support 16 to swivel around its axle 17.

The support 16 is further linked via a lever 26 with a manual, freely rotatable knob 27, which can be used to manualy switch the switch off and to return the switch to the original operating mode, after the switch has been automatically switched off by the circuit due to a long-term increase of current in the protected circuit.

The electric automatic switch operates as follows: in the mode without troubles (as shown by the end position on Fig. 1, position A of the converter 18 and Fig. 2) the main circuit is closed to the connection clamp 2 via electrically conductive means 24, the converter 18, which is in such position that simultaneously both pairs of contacts 15, 22 and 11, 23 are closed, whereby the main circuit flows from the contact 23 to the coil 6, the latter being connected with the clamp 3, wherefrom the protected circuit or a group of circuits with consumer devices continues.

Simultaneously with the mentioned main circuit, the paralelly connected second circuit is also closed during regular operation of the protected circuit, whereby said second circuit is connected to the main circuit in an electrically discharging way on clamps 22 and 15 linked to the magnet yoke 4 and the latter to one end of the means 13, which is with the second end linked to the resistor 12, and the latter series connected to the contact 11 and simultaneously to the coil 6, connected with its other end to the clamp 3.

The current flowing through the main circuit causes an essentially lower power loss in the switch than known solutions.

When a trouble appears in the main circuit (as shown on Fig. 1 , position B of the converter 18 and Fig. 3) in the form of increased electric current of the size determined by the characteristic of the switch, the current flows through the coil 6 causing the small anchor 8 to move and therewith the bar 10 moves as well, so that the latter deflects the converter 18 in a way that the contacts 11 and 23 open, whereby the contacts 15 and 22 still remain closed. The main circuit is thus interrupted and the entire current flows in the first circuit without interruptions, so that the circuits and consumer devices after the switch cannot detect any electric change. After a certain lapse of time, during which the entire increased current flows through the means 13, i.e. all circuits located behind the switch are overloaded and subordinate fuses do not perform their tasks, the means 13 bend so much to shift the tooth 25 thus turning the support 16 around the axle 17 to cause the opening of the contacts 15 and 22. When the support 16 is turned also the knob 27 turns via the lever 26, said knob showing that the switch is in off position.

When a disturbance appears in the main circuit (as shown by the final status on Fig. 1, position C of the converter 18 and Fig. 4) in the form of an excessively and suddenly increased electric current for instance exceeding the nominal current by 100-times, the current flows through the coil 6 causing the axial shift of the large anchor 8 to the core 7 so that the bar 10 reaches its extreme external position thus immediately opening both pairs of contacts 11, 23 and 15, 22. Electric arc appears, which is extinguished in a known way.

If the increased current lasts for a short period of time, the increased magnetic field created by the coil 6 decreases to the original value, the bar 10 loses its force and the springs 19 and 20 return the converter 18 to normal position as shown on Fig. 2.

If the increased current lasts for a longer period of time, the means 13 deform due to the increased current flowing through the first auxiliary circuit, said means pushing against the tooth 25 thus turning the support 16, which turns the knob 27 via the lever 26 to the position shown on Fig. 5. Reset to normal position of Fig. 2 is only possible if the knob 27 is turned manually. It is understandable that a man skilled in the art can conceive also other embodiments based on the knowledge of the above description without circumventing the characteristics of the invention defined in the appended patent claims.

Claims

1. Electric automatic switch consisting of an electrically nonconductive housing (1), preferably of any of standard housings containing at one end a connecting clamp (2) for the supply connection of the electric circuit, which is intended for protection, at the opposite end a connecting clamp (3) for the discharge connection of the electric circuit, which is intended for protection, whereby in the housing (1) there is a first contact (11) electrically connected with a coil (6) and simultaneously with a resistor (12), to which means (13) are electrically connected, said means deforming their shape when an increased current flows through them whereas the means (13) are preferably shaped as the letter U, so that one free end of one leg is electrically connected with the contact (11) and another free end of the second leg is connected with the magnet yoke (4) via the resistor (12), furthermore the housing comprises preferably near the magnet yoke (4) and at the opposite side of the resistor (12) an arc bus (14) with a fire extinguishing chamber (14a), so that the arc bus (14) is electrically connected with the clamp (2) and that it contains a converter (18) with its contact (22) resistant to burning off, which can be electrically conductively connected to a second contact (15) and with its contact (23) electrically conductively with its contact (11) and the converter (18) is moreover uninterruptedly connected via a guide (24), preferably a cord, with the clamp (2), characterized in that the housing (1) houses a magnetic yoke (4), preferably in the shape of a square U, in which a leading bushing (5) is positioned between both free ends of the magnet yoke (4), whereas a coil (6) is positioned on the bushing (5) and at one end of the bushing (5) there is a core (7), and at the opposite end of it there is a large anchor (8) and between the core (7) and the large anchor (8) and within the large anchor (8) there is a small anchor (9) that moves along its axle, whereas in the core (7) there is a bar (10) that moves along its axle and leans at one end on the small anchor (9) and at the other freely protrudes from the magnet yoke (4); furthermore in the area between the clamp (2) and the bar (10) there is a support

(16) rotatable around its axle (17), preferably arranged between the bar (10) and the contact (11), whereby the three-position converter (18) is fastened via two springs (19) and (20) on a swing hinge (21); and in that on the magnet yoke (4) in the vicinity of the arc bus (13) there is another contact (15), which is electrically conductively connected with the magnet yoke (4).

2. Electric automatic switch according to claim 1 characterized in that the converter (18) is fastened with a spring (19) engaging with the converter (18) in the area of the contact (22), in the area of the opposite end, the converter (18) is pivoted in a swing hinge (21) preferably conceived as a bar element having hinge extensions, of which one is intended for fitting into the housing (1) and another into the converter (18).

3. Electric automatic switch according to claims 1 and 2 characterized in that a part of the switch mechanism contains a tooth (25) abutting the transversal leg of the means (13).

4. Electric automatic switch according to claims 1 to 3 characterized in that the support (16) is linked via a lever (26) with a manual, freely rotatable knob (27).

5. Electric automatic switch according to claims 1 to 4 characterized in that the means (13) are a bimetal or a memory element.