US3859611A

US3859611A - Electric switching apparatus

Info

Publication number: US3859611A
Application number: US410025A
Authority: US
Inventors: Jan Christiaan Clason
Original assignee: Hazemeijer BV
Current assignee: Hazemeijer BV
Priority date: 1972-10-30
Filing date: 1973-10-26
Publication date: 1975-01-07
Anticipated expiration: 1992-01-07
Also published as: CA987714A; JPS4977181A; SE387003B; BE806406A; NL7214678A; CH560962A5; JPS5735536B2; FR2204862B1; DE2354133A1; FR2204862A1; NL152106B; GB1443730A; DE2354133B2

Abstract

In an electric switching apparatus an energy accumulator switches the apparatus on or off by movement of a movable member to and from a stationary member. A switching-off spring associated with the energy accumulator is cocked in a switchingon state and is released with the uncoupling of a magnetic locking means mounted between the movable member and the stationary member and including magnetic operating means and an armature plate retained by the magnetic operating means in the switched-on state of the switching apparatus. The magnetic locking means includes a disconnecting mechanism for disengaging the coupling between the magnetic armature plate and the magnetic operating means to switch-off the switching apparatus by means of the energy accumulator. The disconnecting mechanism includes a Dshaft positioned in the interface between the armature plate and the magnetic operating means whereby rotation of the D-shaft uncouples the armature plate from the magnetic operating means. A permanent magnet and a striking pin coupled therewith cooperate with an insulating member and a second permanent magnet mounted on the opposite side of the insulating member from the first mentioned permanent magnet such that the striking pin is moved toward the insulating member to displace the second permanent magnet and rotate the D-shaft in the case of a blown fuse.

Description

United States Patent [191 Clason Jan. 7, 1975 1 ELECTRIC SWITCHING APPARATUS [75] Inventor: Jan Christiaan Clason, Hengelo,

Netherlands [73] Assignee: Hazemeijer B. V., Hengelo,

Netherlands [22] Filed: Oct. 26, 1973 [21] Appl. No.: 410,025 3 O] Foreign Application Priority Data Primary ExaminerI-Iarold Broome 7] ABSTRACT In an electric switching apparatus an energy accumulator switches the apparatus on or off by movement of a movable member to and from a stationary member.

A switching-off spring associated with the energy accumulator is cocked in a switching-on state and is released with the uncoupling of a magnetic locking means mounted between the movable member and the stationary member and including magnetic operating means and an armature plate retained by the magnetic operating means in the switched-on state of the switching apparatus. The magnetic locking means includes a disconnecting mechanism for disengaging the coupling between the magnetic armature plate and the magnetic operating means to switch-off the switching apparatus by means of the energy accumulator. The disconnecting mechanism includes a D-shaft positioned in the interface between the armature plate and the magnetic operating means whereby rotation of the D-shaft uncouples the armature plate from the magnetic operating means.

A permanent magnet and a striking pin coupled therewith cooperate with an insulating member and a second permanent magnet mounted on the opposite side of the insulating member from the first mentioned permanent magnet such that the striking pin is moved toward the insulating member to displace the second permanent magnet and rotate the D-shaft in the case of a blown fuse.

5 Claims, 4 Drawing Figures PATEP TED JAN 7 I575 sum u or 4 v 1 ELECTRIC SWITCHING APPARATUS The invention relates to an electric switching apparatus comprising a stationary portion and a movable portion, which can be moved to and from the stationary portion by means of an energy accumulator in order to switch the switching apparatus on and off, respectively. A magnetic locking device is arranged between the movable portion and the stationary portion of the switching apparatus comprising a magnetic system and a ferromagnetic armature plate. The armature plate in the switched-on condition of the switching apparatus is retained by the magnetic system, so that the switching apparatus is locked in its switched-on condition, the energy accumulator for the switching-off operation is adapted to be charged, its stored energy being released upon uncoupling the locking device. Such an apparatus is known from the US. Pat. No. 3,331,930.

The known switching apparatus is a high-voltage apparatus which is completely insulated by moulding resin, a number of conductors being embedded in the stationary portion. The conductors connect cable connecting pins projecting from the stationary portion and a number of bus bars embedded in the stationary portion with a number of pairs of stationary contacts, which partially project from the stationary portion and can be bridged by so-called switching caps, comprising the movable portion. The known switching apparatus is a three-phase apparatus and thus it has three pairs of stationary contacts. The pairs of stationary contacts are arranged with respect to an axis of symmetry on the sides of an equilateral triangle and the switching caps are coupled to a pneumatic energy accumulator, so that they can be moved to and from the stationary contacts together. Furthermore, there is a magnetic locking device with which the switching apparatus in its switched-on condition, in which the pairs of stationary contacts are bridged by the associated switching caps, is retained. In order to switch the known switching apparatus off, a certain pneumatic pressure is gradually built up in the pneumatic cylinder by means of an air pump. As soon as the force in the switching-off direction exerted on the movable portion of the switching apparatus balances the retaining force of the magnetic locking device, the latter is disengaged, i.e., the armature plate is drawn away from the magnetic system, and the movable portion is removed from the stationary portion with high velocity. The airpump is a footoperated pump, which is connected to the cylinder and operated by the operator, so that there is no constant pressurized air source and the energy accumulator is normally uncharged in the switched-on condition of the switching apparatus.

In order to cause the switch, when one or two fuses which are electrically connected in series with the switching apparatus have blown, to switch off as fast as possible in order to avoid an assymetric load, it is known to provide the switching apparatus with a powder gas generator having a powder gas cartridge, which is ignited if a fuse blows and in which the generated high-pressure gases are used for automatically switching off the switching apparatus (see US. Pat. No. 3,264,434).

The present invention has for its object to avoid the the complications of the application of the powder gas generator.

The invention provides an apparatus of the type described above, which is characterized in that the magnetic locking device is provided with a disconnecting mechanism, which at its operation disengages the coupling between the armature plate and the magnetic system, whereafter the switching apparatus under the influence of the continuously charged energy accumulator is switched off.

Thus in the apparatus according to the invention no progressively increasing force in the switching-off direction is first exerted on the movable portion, which force cannot cause the switching apparatus to be switched off until the retaining force of the magnetic locking device will be exceeded. In contradistinction thereto, a predetermined force in the switching-off direction is built up first, which force does not exceed the retaining force of the magnetic locking device, whereafter the magnetic locking device is disengaged in a mechanical way.

If according to a preferred embodiment of the invention, the energy accumulator comprises one or more switching-off springs, which are stretched during the switching-on operation of the switching apparatus, the energy accumulator is continuously charged in the switched-on condition of the switching apparatus, so that it is not necessary first to charge the energy accumulator if one or more fuses have blown.

According to a preferred arrangement, the disconnecting mechanism comprises a D-shaft, the flattened portion of which is normally positioned in the interface between the armature plate and the magnetic system. The rotation of the D-shaft urges the armature plate away from the magnetic system.

A high-voltage fuse is usually provided with a socalled striking pin, which if the fuse blows, shoots outwardly and according to the present invention the striking pin is coupled to a permanent magnet, which is pressed away by the striking pin and influences a second permanent magnet through an insulating wall of the stationary portion of the switch apparatus. The second permanent magnet is displaced thereby and rotates the D-shaft. In this way an excellent electric insulation between the live magnet of the striking pin and the transmission mechanism for the magnetic locking device is achieved.

The transmission mechanism between the striking pin and the D-shaft is provided with a manual switching-off member with which the switching apparatus can be switched off and also the transmission mechanism can be reset into the initial condition, after the blown fuses have been replaced.

The invention will now further be explained in reference to the annexed drawings, in which:

FIG. 1 is a longitudinal cross-section of the electric switching apparatus, in which only a small part of the stationary portion of the switching apparatus is illustrated in its switched-off condition;

FIG. 2 is a cross section along line IlIl in FIG. 3, only a small part .of the movable switch being visible a larger part of the stationary portion of the switching apparatus beingillustrated;

FIG. 3 is a side view from the left side in FIG. 2, and

FIG. 4 is a plan view as well as a cross section according to the line IVIV in FIG. 2.

The switching apparatus comprises a stationary portion 1, formed by an insulating moulding resin, in which a number of conductors are embedded, and a movable portion 2, mainly comprising switching caps 3, three of which are present in the embodiment, but of which only one is visible in FIG. 1.

The switching caps 3 are mechanically coupled to the pneumatic driving cylinder 4, and they can together be moved to and from the stationary portion 1 by cylinder 4. The stationary contacts, which can be bridged by the switch caps 3, are disposed on the stationary portion 1 in the projections 5. For the mechanical guidance of the unit comprising the driving cylinder 4 and the switch caps 3, three sliding shoes 6 are arranged between the three switch caps, and the sliding shoes are also mechanically connected to the driving cylinder 4 and are capable of sliding to-and-fro over the guiding rods 7. Between the sliding shoes 6 and a projection 8 is a switching-off spring 9, which in the switched-on condition of the switching apparatus (see FIG. 2) is stretched or drawn. In the stationary portion 1 of the switching apparatus a magnetic system is embedded, and it comprises three permanent magnets 10. The three magnets 10 like the three phases of the switching apparatus are arranged symmetrically around the axis of symmetry. In the switched-on condition of the switching apparatus (see FIG. 2) the ferromagnetic armature plate 11 arranged at the end of the pneumatic cylinder 4, is retained by the magnetic system 10. For disengaging the magnetic locking device, comprising the magnet system 10 and the armature plate 11, a disconnecting mechanism is provided which comprises a D-shaft 12, supported in two

brackets

13, 14 which are partially embedded in the moulding resin 1. The D- shaft 12 has a flattened portion 15 (see FIG. 1) which in coupled condition of the magnetic locking device lies in the interface between the pole shoes of the magnetic system 10 and the armature plate 11 (see FIG. 2). The D-shaft 12 has at its other end a vane 16 against which an axially movable pin 17 can be pushed.

The switching apparatus has also three fuses 18, one of which is visible in FIG. 2. Fuse 18 comprises an insulating sheath 19 and two metallic terminal contacts, of which contact 20 in FIG. 2 is provided with a switchingoff or striking pin 22 cooperating with the permanent magnet 21. Permanent magnet 21 is pushed to the left by the switching-off pin 22 through the insulating disc or piston 21a, as soon as the concerned fuse 18 blows. It is observed, that the fuse 18 as well as the permanent magnet 21 are completely insulated from the surroundings by insulating material 1. At the other end of the insulating wall 23, towards the permanent magnet 21 is pushed, a second permanent magnet 24 is arranged, and from FIG. 3 it appears, that there are a total of three such magnets, which are respectively arranged at the ends of the arms of a tilting lever 25. Lever 25 is rotatably supported on the pin 26. As soon as a fuse 18 blows, the permanent magnet 24 on the tilting lever 25 is repelled or attracted according to the polarity, in the present case repelled, by the permanent magnet 21 coupled to the striking pin 22, whereby the tilting lever 25 in FIG. 3 is rotated in clock-direction and leaves the abutment pin 27. The tilting lever 25 is provided with a projection 28, which normally lies against a pendulum 29, which is mounted on the pivot 30. Accordingly, if the tilting lever 25 leaves the abutment pin 27 and rotates to the right in FIG. 3, the pendulum 29 is rotated in anti-clock direction across its deadpoint, whereafter pendulum 29 swings toward the abutment 31, so that the bevelled portion 32 slides across the end of the pin l7 projecting from the insulating material 1 and presses pin 17. Thereby the vane 16 on the D-shaft 12 is rotated whereby the ferromagnetic armature plate 11 is urged away from the magnetic system 10, and the movable portion 2 of the switching apparatus is driven into the switching-off direction under the influence of the stretched switching-off springs 9 into the completelyswitched-off position of FIG. 1.

In order to be able to switch-off the switching apparamechanism is enclosed inder 4. A magnetic locking device is also arranged for the switching-on operation, and it is arranged in the end 37 of cylinder 4. This magnetic locking device, however, operates in a known way and is disengaged automatically, as soon as the pressure in the pneumatic cylinder 4 exceeds a predetermined threshold value. The movable portion 2 of the switching apparatus comprising the cylinder 4, the switching caps 3 and the sliding shoes 6 is arranged in a plastic cap 38.

What we claim is:

1. An electric switching apparatus, comprising:

a stationary member and a movable member;

an energy accumulator for switching the apparatus on or off by movement of said movable member to and from said stationary member, and including at least one switching-off spring;

magnetic locking means mounted between said movable member and said stationary member and including magnetic operating means and a ferromagnetic armature plate retained by said magnetic operating means in the switched-on state of said switching apparatus, thereby locking said switching apparatus in the switched-on state;

said switching-off spring is cocked in the switchingon state and is released with the uncoupling of said magnetic locking means; said magnetic locking means including a disconnecting mechanism for disengaging the coupling between said magnetic armature plate and said magnetic operating means to switch-off said switching apparatus through said energy accumulator; and

said disconnecting mechanism includes a D-shaft having a flattened portion positioned in the interface between said armature plate and said magnetic operating means with said switching apparatus in the on state, said D-shaft rotating to uncouple said armature plate from said magnetic operating means.

2. Apparatus as in claim 1 further comprising a fuse and means for indicating the condition of said fuse, and wherein said D-shaft is coupled to said fuse indicating means, whereby said switching apparatus is switched off with said fuse blown.

3. Apparatus as in claim 2 wherein said fuse indicating means include a first permanent magnet and a strik- D-shaft, whereby movement of said first and second permanent magnets toward one another rotates said tilting lever to release said pendulum to engage said pin and rotate said vane.

5. Apparatus as in claim 4 further comprising a manual switching-off member coupled with said pendulum, whereby said switching apparatus is switched-off and for rotating said pendulum to an initial position with the replacement of a blown fuse.

Claims

1. An electric switching apparatus, comprising: a stationary member and a movable member; an energy accumulator for switching the apparatus on or off by movement of said movable member to and from said stationary member, and including at least one switching-off spring; magnetic locking means mounted between said movable member and said stationary member and including magnetic operating means and a ferro-magnetic armature plate retained by said magnetic operating means in the switched-on state of said switching apparatus, thereby locking said switching apparatus in the switched-on state; said switching-off spring is cocked in the switching-on state and is released with the uncoupling of said magnetic locking means; said magnetic locking means including a disconnecting mechanism for disengaging the coupling between said magnetic armature plate and said magnetic operating means to switch-off said switching apparatus through said energy accumulator; and said disconnecting mechanism includes a D-shaft having a flattened portion positioned in the interface between said armature plate and said magnetic operating means with said switching apparatus in the on state, said D-shaft rotating to uncouple said armature plate from said magnetic operating means.

2. Apparatus as in claim 1 further comprising a fuse and means for indicating the condition of said fuse, and wherein said D-shaft is coupled to said fuse indicating means, whereby said switching apparatus is switched-off with said fuse blown.

3. Apparatus as in claim 2 wherein said fuse indicating means include a first permanent magnet and a striking pin coupled therewith, said stationary member includes an insulating member and a second permanent magnet mounted on the oppostie side of said insulating member from said first permanent magnet, whereby said striking pin is moved toward said insulating member with said fuse blown to displace said second permanent magnet and rotate said D-shaft.

4. Apparatus as in claim 3 further comprising a tilting lever for supporting said second permanent magnet, a pendulum, a pin member, and a vane mounted to said D-shaft, whereby movement of said first and second permanent magnets toward one another rotates said tilting lever to release said penduluM to engage said pin and rotate said vane.