CN1074852C - Circuit breaker - Google Patents

Abstract

The present invention relates to a circuit breaker which is characterized in that a side connecting rod (54) of a handle of a toggle rod mechanism (58) is provided with a cam part (54a). when contacts are welded to enable the handle (62) to move to the broken circuit position, the cam part (54a) is clamped with a bend clamping part (59a) of a handle arm (59) to prevent the handle (62) from being moved to the broken circuit position. The device has the advantages that the handle (62) can not be moved to the broken circuit position under the condition that a movable contact (44a) is welded with a fixed contact (43a), and the handle arm (59) can be made to be small.

Description

Circuit-breaker

Technical field

The present invention relates to behind the moving contact and fixed contact welding of circuit-breaker, can not make handle move to the circuit-breaker of off position.

Background technology

Figure 11 is a cutaway view of representing the existing circuit-breaker that discloses on 1989 No. 42286 communique of the bulletin of Japanese Utility Model for example.Among the figure, the 1st, lid, the 2nd, base, all form with synthetic resin, the 3rd, the framework that constitutes by above-mentioned lid 1 and base 2, the 4th, be fixed on the fixed contact therefor on the base 2, and at one end has terminal component 5 so that can connect external conductor (not shown), on the other end, has fixed contact 6, the 7th, have the movable contact of the moving contact 8 relative with this fixed contact 6, the 9th, rotate the movable contact arm that freely this movable contact 7 is supported with fulcrum post 10,11 are mounted between this movable contact arm 9 and the movable contact 7 and all the time to the crimp spring of fixed contact 6 directions to movable contact 7 additional forces, the 12nd, whole be arranged side by side on extremely by connecting the transverse arm that insulant constituted of movable contact arm 9 one ends separately, the 13rd, to above-mentioned two contacts 6, the electric arc that takes place between 8 carries out the arc-extinction device of extinguishing arc, and more than 15 assortment of magnetic sheet that extinguishing arc is used is in the inboard of a pair of extinguishing arc side plate 14,16 is end utilization axles 17 and rotate the lower link be bearing in freely on the movable contact arm 9, the 18th, use axle 20 respectively, 21 and rotate freely an end bearing on the other end of lower link 16, the other end is bearing in the upper links on the carriage 19, the 22nd, by lower link 16, upper links 18 and 20 formations of axle, axle 20 becomes the elbow-bar mechanism of ancon, the 23rd, rotate the handle arm that freely an end (not shown) is bearing on the assigned position relative to this elbow-bar mechanism 22, the 24th, an end is hung on the handle arm 23 by spring mount pin 25, the other end is hung on the elbow formula spring of axle on 20, the 26th, can be from covering the handle with synthetic resin formation of 1 peripheral operation, and with handle arm 23 interlocks, the 27th, the bimetallic that is connected with movable contact 7, the 28th, be fixed on the fixed iron core on this bimetallic 27, the 29th, be adapted to the movable core relative with this fixed iron core 28, the 30th, fix the rotation trip(ping) bar freely of this movable core 29, the 31st, a slice is ended another sheet with carriage 19 cards all the time and is blocked the rotation claw freely that ends with trip(ping) bar 30 all the time, the 32nd, rotate the bracket axle that freely carriage 19 is supported, the 33rd, the time block the block of carriage 19 in tripping operation, engage with support 34 and fix.In addition, the fulcrum by the rotation usefulness of the location of described bracket axle 32 and claw 31 supports this support 34.

Describe with regard to operation principle below.Become among Figure 12 of off state in the contact, under the state that carriage 19 and claw 31 cards end, if make handle 26 swing to closed circuit position (Right deviation), then elbow-bar mechanism 22 is extended, and moving contact 8 contacts with fixed contact 6, becomes closed circuit state shown in Figure 11.Then, if make handle 26 swing to off position ("Left"-deviationist), then elbow-bar mechanism 22 is bent, and moving contact 8 leaves fixed contact 6, becomes off state shown in Figure 12.In addition, when when in circuit, flowing through overcurrent under the above-mentioned closed circuit state shown in Figure 11, owing to bimetallic 27 or movable core 29 move engage (with reference to the Figure 13) that removes carriage 19 and claw 31, so carriage 19 is that middle mind-set clockwise direction rotates with bracket axle 32, therefore, the tie point of carriage 19 and upper links 18 is the position that the point of axle 21 is crossed elbow formula spring 24, thereby utilize the spring force of elbow formula spring 24 and make elbow-bar mechanism 22 bendings, and carry out each utmost point interlock by transverse arm 12, moving contact 8 leaves fixed contact 6 and becomes tripped condition shown in Figure 13 with the whole utmost point.

In aforesaid circuit-breaker, just in case the occasion of the state that welding fails to throw off takes place to carry out under closed circuit state because of the movable contact 7 of abnormal current, as shown in figure 14, if handle 26 is moved to a closed circuit side, then make elbow formula spring 24 above normally extending and may making handle 26 move, stop on the off position, the expression position of opening circuit of handle 26 is just inconsistent with the closed circuit position of the movable contact 7 of reality.

In addition, example as prior art, the existing Japanese patent of invention bulletin circuit-breaker that 1989 No. 39176 communique disclosed, when it carried out welding between the contact, opening (being equivalent to handle arm) engaged with movable contact arrangement and can not make handle move to off position.

In aforesaid existing circuit-breaker, because of the movable contact of abnormal current after carrying out welding under the closed circuit state, though can stop handle to move to off position, because handle arm is directly engaged with movable contact arrangement, so exist the shortcoming that handle arm is maximized.

For solving the shortcoming of above-mentioned existence, the objective of the invention is to, a kind of circuit-breaker is provided, it can not make handle move to off position after moving contact and fixed contact welding, can do handle arm less simultaneously.

Another purpose also is, after moving contact and the fixed contact welding, can not make handle move to off position, the mechanism that can do handle arm less and firm simultaneously.

Disclosure of an invention

In the circuit-breaker of the present invention, comprising: the fixed contact therefor on the insulation framework inside that constitutes by base and lid; Relative with described fixed contact therefor and contact, separate movable contact; Drive the elbow-bar mechanism of described movable contact; Rotate the handle arm that is bearing in freely on the assigned position relative to described elbow-bar mechanism; Make to link, make the tripgear of elbow-bar mechanism action with overcurrent, its characteristics are, on elbow-bar mechanism, be provided with in fixed contact during, engage with handle arm and stop handle to move to the prevention parts of off position with the moving contact welding, thus, when can stoping handle to move to off position, can do handle arm less.

In addition, stop parts to be arranged on the handle side connecting rod of elbow-bar mechanism and engage with handle arm during with the moving contact welding and stop handle to move to the cam part of off position in fixed contact.Thus, can stop handle when the off position direction moves, can do handle arm less.

In addition, the prevention parts that engage with the handle arm of the handle side connecting rod of elbow-bar mechanism are that the circular-arc cam part at center forms by the fulcrum of handle side connecting rod.Consistent by the fulcrum that makes the handle side connecting rod with the center of cam part, and make the rotation of handle side connecting rod, but because of handle does not move to the clamped position that surpasses with cam part to the off position direction, so clearly represent contact weld.

In addition, when fixed contact and moving contact welding with handle in the process that the direction that opens circuit moves, the cam part that engages with the handle arm of handle side connecting rod is formed by the 2nd cam part that engages with above-mentioned handle arm the early stage at this moving process and the 1st cam part that engages with above-mentioned handle arm in the later stage of above-mentioned moving process.Thus, circuit-breaker makes handle from the closed circuit state to the off state in the process that counterclockwise moves, because the bending engaging part of handle arm engages with the 2nd cam part of handle side connecting rod, and make the handle side connecting rod crooked rapidly with the link of movable contact side connecting rod, so the action of opening circuit is more reliable.And, under the less situation of the as-welded of contact, have the moment that utilization produces to clockwise direction and mention movable contact and make the effect of contact separation.In addition, by moving and engaging, more stop handle to move to the off position direction with the 1st cam part.

In addition, the cam part that engages with the handle arm of handle side connecting rod is the 1st circular-arc cam part at center and is formed with the 2nd circular-arc cam part that movable contact side connecting rod one side of the fulcrum of handle side connecting rod is the center by the fulcrum of handle side connecting rod.Thus, circuit-breaker makes handle from the closed circuit state to the off state in the process that counterclockwise moves, because the bending engaging part of handle arm engages with the 2nd cam part of handle side connecting rod, and make the handle side connecting rod crooked rapidly with the link of movable contact side connecting rod, so the action of opening circuit is more reliable.And, under the less situation of the as-welded of contact, have the moment that utilization produces to clockwise direction and mention movable contact and make the effect of contact separation.In addition, by moving and engaging, more stop handle to move to the off position direction with the 1st cam part.

In addition, in circuit-breaker, be equipped with: the fixed contact therefor on the insulation framework inside that constitutes by base and lid; Relative with described fixed contact therefor and contact, separate movable contact; The transverse arm that connects described movable contact one end; Drive the elbow-bar mechanism of movable contact; Rotate the handle arm that is bearing in freely on the assigned position relative to described elbow-bar mechanism; Handle with described handle arm interlock; Make to link, make the tripgear of elbow-bar mechanism action with overcurrent, its characteristics are, between transverse arm and handle arm, be provided with when the moving contact welding of the fixed contact of fixed contact therefor and movable contact, be fastened on transverse arm and handle arm each other and the block that the prevention handle moves to off position, thus, because of when can stoping handle to move to off position, can do handle arm less, and block is contacted with firm transverse arm, even so more or less act on undue power, can not destroy yet, become firm mechanism.

Again, be provided with torsionspring, it is positioned near the handle arm, and a pin makes block make resilient bias and block is engaged with handle arm to handle arm.Thus, by all the time to handle arm to the clockwise direction additional force, handle just moves to closed circuit direction reliably, and makes the contact position of circuit-breaker and the show state of handle have the effect of reliably getting in touch.

The simple declaration of accompanying drawing

Fig. 1 is the side sectional view of the circuit-breaker of the expression embodiment of the invention 1, and the expression closed circuit state.

Fig. 2 is the side sectional view of the major part of the circuit-breaker of presentation graphs 1 when being off state.

Fig. 3 is that the circuit-breaker of presentation graphs 1 is the side sectional view of the major part of tripped condition.

The side sectional view that Fig. 4 is in the state of contact after welding of circuit-breaker of presentation graphs 1, handle moves the back state to the off position direction.

Fig. 5 is the side sectional view of the circuit-breaker of the expression embodiment of the invention 2.

Fig. 6 is in the state of contact after welding of circuit-breaker of presentation graphs 5, handle moves the side sectional view that the major part of back state is amplified to the off position direction.

Fig. 7 is the expression elbow-bar mechanism moves the major part amplification of back state from Fig. 6 state a side sectional view.

Fig. 8 is the side sectional view of the circuit-breaker of the expression embodiment of the invention 3, and the expression closed circuit state.

The side sectional view that Fig. 9 is in the state of contact after welding of circuit-breaker of presentation graphs 8, handle moves the back state to the off position direction.

Figure 10 is the side sectional view of the circuit-breaker of the expression embodiment of the invention 4.

Figure 11 is the side sectional view of the existing circuit-breaker of expression, and the expression closed circuit state.

Figure 12 is the side sectional view of the existing circuit-breaker of expression, and the expression off state.

Figure 13 is the side sectional view of the existing circuit-breaker of expression, and the expression tripped condition.

Figure 14 is the side sectional view of the existing circuit-breaker of expression, and the expression contact moves to the state of off position at the as-welded lower handle.

The optimal morphology that carries out an invention

Fig. 1 is that the circuit-breaker with the embodiment of the invention 1 cuts a part showing inner side sectional view, and the expression closed circuit state.Fig. 2 is the side sectional view of the major part of the circuit-breaker of presentation graphs 1 when being off state, and Fig. 3 is the side sectional view of the major part of the circuit-breaker of presentation graphs 1 when being tripped condition.Among the figure, the 40th, lid, the 41st, base all forms with synthetic resin.The 42nd, the framework that constitutes by above-mentioned lid 40 and base 41, the 43rd, be fixed on the fixed contact therefor on the base 41, and have fixed contact 43a.The 44th, have the movable contact of the moving contact 44a relative, and rotate supporting freely by fulcrum post 45 with this fixed contact 43a.The 46th, whole be arranged side by side on extremely by the transverse arm that insulant constituted that connects movable contact 44 1 ends separately.47 are mounted between movable contact 44 and the transverse arm 46 and all the time to the crimp spring of fixed contact 43a direction to movable contact 44 additional forces.The 48th, the pliability conductor, an end is connected with movable contact 44, and the other end is connected with tripgear (not shown).The 49th, the electric arc that takes place between two contact 43a, the 44a is carried out the arc-extinction device of extinguishing arc, and more than 51 assortment of magnetic sheet that extinguishing arc is used is in the inboard of a pair of extinguishing arc side plate 50.

52 is the movable contact side connecting rod be bearing in freely on the transverse arm 46 of an end utilization axle 53 and rotate (below be called lower link), the 54th, rotate with axle 56,57 respectively freely with an end bearing on the other end of lower link 52, the other end is bearing in handle side connecting rod on the carriage 55 (below be called upper links), and is provided with the prevention parts on upper links 54.Specifically, these prevention parts are by being formed with axle 57 the central point that the becomes upper links 54 fulcrums circular-arc cam part 54a by radius centered R.The 58th, by the elbow-bar mechanism that lower link 52, upper links 54 and 56 on axle constitute, axle 56 becomes ancon.The 59th, handle arm has bending engaging part 59a, and rotate freely at assigned position relative to elbow-bar mechanism 58, an end 59b becomes rotating fulcrum and is bearing on the not shown support.The 60th, respectively an end is hung on the handle arm 59, the other end is hung on elbow formula spring on the axle 56 by spring mount pin 61, the 62nd, can be from covering the handle that forms with synthetic resin of 40 peripheral operations, and with handle arm 59 interlocks.The 63rd, the button pawl has the button pawl engaging part 63a that engages with carriage 55, the recess 63b that embeds button pawl bolster 64, and engages with tripgear (not shown), is that rotate at the center with button pawl bolster 64.The 65th, be bearing in the bearing bracket axle on the not shown support, the 66th, the backing pin of upper links 54 and movable contact 44.

Describe with regard to operation principle below.Become among Fig. 2 of off state in the contact, under the state that carriage 55 and button pawl 63 cards end, if make handle 62 swing to closed circuit position (Right deviation), then elbow-bar mechanism 58 is extended, and moving contact 44a contacts with fixed contact 43a, becomes closed circuit state shown in Figure 1.Then, if make handle 62 swing to off position ("Left"-deviationist), then when the axis of elbow formula spring 60 surpasses axle 56 with spool 57 positions that are connected (dead point), elbow-bar mechanism 58 bendings and lower link 52 is mentioned, moving contact 44a leaves fixed contact 43a, becomes off state shown in Figure 2.In addition, when when in circuit, flowing through overcurrent under the above-mentioned closed circuit state shown in Figure 1, owing to carriage 55 and engage (with reference to the Fig. 3) that detains pawl 63 are removed in tripgear (not shown) action, so carriage 55 is that middle mind-set clockwise direction rotates with bearing bracket axle 65, therefore, the tie point of carriage 55 and upper links 54 is the position that the point of axle 57 is crossed elbow formula spring 60, thereby utilize the spring force of elbow formula spring 60 and make elbow-bar mechanism 58 bendings, and carry out each utmost point interlock by transverse arm 46, moving contact 44a leaves fixed contact 43a and becomes tripped condition shown in Figure 3 with the whole utmost point.

Fig. 4 for example represents at the big electric current of the dirty extra pulse shape of closed circuit state and at the engaging under the undissolved state generation welding phenomenon between fixed contact 43a and moving contact 44a of carriage 55 and button pawl 63 and the occasion that moving contact 44a does not throw off.In this state, elbow-bar mechanism 58 remains on the position of closed circuit state, as shown in Figure 4, because maintenance inspections etc. need, for placing off state that handle 62 is moved to the side that opens circuit to counter clockwise direction, then elbow formula spring 60 elongations, handle arm 59 is also rotated to counter clockwise direction, and moves to the off position direction.But in the way of counterclockwise moving, the bending engaging part 59a of handle arm 59 engages with the upper links 54 cam part 54a collision of the elbow-bar mechanism 58 that is held in closed circuit state, more stops handle arm 59 to move to the off position direction at handle 62.

In addition, the bending engaging part 59a of handle arm 59 also can engage it with the lower link collision of the elbow-bar mechanism 58 that is held in closed circuit state.So, owing to the prevention parts on the elbow-bar mechanism 58, specifically cam 54a collides with the bending engaging part 59a of handle arm 59 and engages, engage so the handle arm movable contact arrangement more such than prior art collided with handle arm and do for a short time.

Fig. 5 is that the circuit-breaker with the embodiment of the invention 2 cuts a part and represents inner side sectional view, and be illustrated in the state after the contact weld of circuit-breaker, the state of handle after the off position direction moves.The side sectional view that Fig. 6 is in the state that is illustrated in after the contact weld of circuit-breaker of Fig. 5, the major part of the state of handle after the off position direction moves is amplified.Among the figure, the 100th, upper links, and the shape of the cam part that engages with the bending engaging part 59a of handle arm 59 is in order to the central point C1 of axle 57 the 1st cam part 100a that to be the center form with radius R 1 with to make central point C2 and the 2nd cam part 100b that forms with radius R 2 as the center forms in the optional position of only leaving axle 57 central point C1 size L in lower link 52 1 sides.For example, under the situation of the circuit-breaker of 400A (peace doubly) support, the set positions of central point C2 is in the scope of L=2.5～3mm, central point C1 rotates θ and is about on 20 the positions after spending with chain-dotted line clockwise direction after the central point C3 of axle 56 is connected relatively.

Be for example to represent under closed circuit state and flowing through the big electric current of pulse type and the engaging under the state that is not disengaged generation welding phenomenon between fixed contact 43a and moving contact 44a of carriage 55 and button pawl 63 and situation that moving contact 44a does not throw off in the state of Fig. 5.In this state, shown in the side sectional view that the detailed major part of Fig. 6 is amplified, because maintenance inspections etc. need, for placing off state that handle 62 is moved to the side that opens circuit to counter clockwise direction, then elbow formula spring 60 elongations, handle arm 59 is also rotated to counter clockwise direction, and moves to the off position direction.But in the way of counterclockwise moving, that is, in the early stage of the process that moves to the direction that opens circuit at handle 62, the bending engaging part 59a of handle arm 59 engages with the 2nd cam part 100b of upper links 100 at handle 62.At this moment, on the contact point of the bending engaging part 59a of the 2nd cam part 100b and handle arm 59, act on pressing force F2 to central point C2.Because the direction of this F2 moves to the direction of central point C2, so acting on axle 57 central point C1 on upper links 100 is the clockwise moment M=F2 of fulcrum * L, and the axle 56 that connects upper links 100 and lower link 52 is rotated to arrow D direction, as shown in Figure 7, thereby mention lower link 52 to the arrow E direction, make movable contact 44 break away from fixed contact therefors 43, but because contact weld, so only mobile and stop with clearance G (with reference to Fig. 6) amount.By with axle 56 part bendings, make the bending engaging part 59a of handle arm 59 move to the position that engages with the 1st cam part 100a, at this moment, i.e. later stage of the process that moves to the direction that opens circuit at handle 62, since with the contact point of the 1st cam part 100a on to central point C1 effect pressing force F1, so more stop handle arm 59 to move to the off position direction.

Adopt present embodiment 2, then from the closed circuit state to the off state, make handle 62 in the process that counterclockwise moves at circuit-breaker, because the bending engaging part 59a of handle arm 59 engages with the 2nd cam part 100b of upper links 100, make upper links 100 crooked rapidly, so the action of opening circuit is more reliable with the connecting portion of lower link 52.In addition, under the less situation of the as-welded of contact, have and mention movable contact 44 by clockwise moment M=F2 * L and make the effect of contact separation.Again, rotate to bending direction by upper links 100, the 1st cam part 100a is engaged with the bending engaging part 59a of handle arm 59, then upper links 100 rotates to the state that movable contact 44 is mentioned, but stops handle 62 to move to the off position direction from engage the position, back with cam part 100a.

Fig. 8 is that the circuit-breaker with the embodiment of the invention 3 cuts a part and represents inner side sectional view, and the expression closed circuit state.Among the figure, 1～66th, the label identical, its explanation of Therefore, omited with the foregoing description 1.The 70th, block, by the block bolster 65 rotations supporting freely of carriage 55, an end is formed with arm member 70a, and the other end is fixed with the gear shaft 71 that engages with the bending engaging part 59a of handle arm 59.

Fig. 9 for example represents at the big electric current of the dirty extra pulse shape of closed circuit state and the engaging under the state that is not disengaged generation welding phenomenon between fixed contact 43a and moving contact 44a of carriage 55 and button pawl 63 and situation that moving contact 44a does not throw off.In the state of this contact weld, because maintenance inspections etc. need, and from Fig. 8 state handle 62 are moved to the side that opens circuit to counter clockwise direction for placing off state, then elbow formula spring 60 elongations, handle arm 59 is also rotated to counter clockwise direction, and moves (with reference to Fig. 9) to the off position direction.But at handle 62 in the way of counterclockwise moving, make axle 71 with the bending engaging part 59a butt of handle arm 59 to counterclockwise rotating, thus, the arm member 70a of block 70 is to counterclockwise rotating and with the protrusion member 46a collision of firm transverse arm 46 and engage, stop handle arm 59 to move as shown in Figure 9, and more to the off position direction.The handle arm movable contact arrangement more such than prior art collided with handle arm and engage does for a short time.

Figure 10 is the end view of the circuit-breaker of the expression embodiment of the invention 4.Among the figure, the 72nd, torsionspring engages with gear shaft 71, and makes the bending engaging part 59a butt of gear shaft 71 and handle arm 59 all the time, all the time to clockwise direction to block 70 additional forces.

The spiral part 72a of torsionspring 72 rotates and is journaled into freely on the bearing bracket axle 65, and bearing bracket axle 65 is journaled on the not shown support.72 1 pin 72b of torsionspring engage with gear shaft 71 on being fixed on block 70, make block 70 make resilient bias and block 70 is engaged with handle arm 59 to handle arm 59, and another pin 72c engages with backing pin 66, and backing pin 66 is journaled on the not shown support.

Adopt present embodiment 4, torsionspring 72 becomes handle arm 59 and handle 62 to clockwise additional force for the additional force of block 70.

Claims (7)

1. a circuit-breaker is equipped with: the fixed contact therefor (43) on insulation framework (42) inside that is made of base (41) and lid (40); Relative with described fixed contact therefor (43) and contact, separate movable contact (44); Drive the elbow-bar mechanism (58) of described movable contact (44); Rotate the handle arm (59) that is bearing in freely on the assigned position relative to described elbow-bar mechanism (58); Handle (62) with described handle arm (59) interlock; Make to link, make the tripgear of described elbow-bar mechanism (58) action with overcurrent, it is characterized in that, on described elbow-bar mechanism (58), be provided with when moving contact (44a) welding of the fixed contact (43a) of described fixed contact therefor (43) and described movable contact (44), engage with described handle arm (59) and stop described handle (62) to move to the prevention parts (54a) of off position.

2. circuit-breaker as claimed in claim 1, it is characterized in that blocking portion (54a) is to go up and engage with handle arm (59) during moving contact (44a) welding at the fixed contact (43a) of fixed contact therefor (43) and movable contact (44) and stop handle (62) to move to the cam part (54a) of off position at the handle side connecting rod (54) that elbow-bar mechanism (58) is set.

3. circuit-breaker as claimed in claim 1 or 2, it is characterized in that, the prevention parts (54a) that engage with the handle arm (59) of the handle side connecting rod (54) of elbow-bar mechanism (58) are that the circular-arc cam part (54a) at center forms by the fulcrum of described handle side connecting rod (54).

4. circuit-breaker as claimed in claim 2, it is characterized in that, when fixed contact (43a) and moving contact (44a) welding with handle (62) in the process that the direction that opens circuit moves, the cam part (54a) that engages with the handle arm (59) of handle side connecting rod (54) is formed by the 2nd cam part (100b) that engages with described handle arm (59) early stage at this moving process and the 1st cam part (100a) that engages with described handle arm (59) in the later stage of described moving process.

5. circuit-breaker as claimed in claim 4, it is characterized in that, the cam part (54a) that engages with the handle arm (59) of handle side connecting rod (54) is circular-arc the 1st cam part (100a) at center and is that circular-arc the 2nd cam part (100b) at center forms with movable contact side connecting rod (52) one sides of the fulcrum of handle side connecting rod (54) by the fulcrum of described handle side connecting rod (54).

6. a circuit-breaker is equipped with: the fixed contact therefor (43) on insulation framework (42) inside that is made of base (41) and lid (40); Relative with described fixed contact therefor (43) and contact, separate movable contact (44); The transverse arm (46) that connects described movable contact (44) one ends; Drive the elbow-bar mechanism (58) of described movable contact (44); Rotate the handle arm (59) that is bearing in freely on the assigned position relative to described elbow-bar mechanism (58); Handle (62) with described handle arm (59) interlock; Make to link, make the tripgear of described elbow-bar mechanism (58) action with overcurrent, it is characterized in that, between described transverse arm (46) and described handle arm (59), be provided with when moving contact (44a) welding of the fixed contact (43a) of described fixed contact therefor (43) and described movable contact (44), be fastened on the block (70) that stops described handle (62) to move each other of described transverse arm (46) and described handle arm (59) to off position.

7. circuit-breaker as claimed in claim 6, it is characterized in that, have torsionspring (72), it is positioned near the handle arm (59), and a pin (72b) makes block (70) make resilient bias and block (70) is engaged with handle arm (59) to handle arm (59).

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