JP4863372B2 - Circuit breaker for wiring - Google Patents

Description

  The present invention relates to a thermal tripping circuit breaker, and more particularly to a wiring breaker provided with a metal tripping mechanism.

  Thermally tripping type circuit breaker is provided with a tripping structure adjacent to the bimetal through which the load current flows, and the tripping mechanism is operated by tripping the deformation of the bimetal due to overcurrent to the structure. It has become. This tripping structure is provided with a bimetal adjusting screw for adjusting the IT characteristic, that is, the current-time characteristic by changing the gap with the bimetal. In addition, there is a structure in which a metal fitting for fixing a bimetal is deformed and adjusted with an adjustment screw, or a structure in which a tap is cut on the bimetal and an adjustment screw is attached.

  The material of the tripping structure is made of metal (Patent Document 1) or synthetic resin (Patent Document 2) depending on the performance of the breaker. In the case of metal, the IT characteristic is adjusted. After that, an adjustment screw was fixed by applying a screw loosening prevention material. Since metal parts have higher rigidity than synthetic resin parts, the shape of the parts can be made thinner, resulting in a smaller product, and in the case of the thermal tripping type and the electromagnetic type, a movable iron piece and a tripping member are used. It can also be used. However, screw loosening prevention materials have problems such as that it takes time to dry, and in some cases, a dedicated device such as a dryer is required, and there is a risk that it may drip into other locations and cause problems. The time was annoying.

On the other hand, when the tripping structure is made of synthetic resin, it is possible to fix the screw by the viscosity of the synthetic resin itself without using a screw loosening prevention material. However, when the tripping structure is made of a synthetic resin, there is a problem in that it becomes thicker and larger than that of a metal and hinders downsizing of the product.
JP-A-9-180618 JP-A-7-220607

  Accordingly, the object of the present invention is to solve the conventional problems, and to provide a circuit breaker for wiring that does not require a complicated screw fixing work with a screw loosening prevention material and can adjust the IT characteristics as in the conventional case. It is to be.

The present invention made in order to solve the above problems is a thermal trip type circuit breaker, in a portion that hangs downward from the upper end of the trip structure constituting the metal trip mechanism. A synthetic resin screw tightening member having a U-shaped hole and a protrusion at the lower end that engages with the lower vertical surface of the hole is fitted into the hole. A bimetal adjusting screw is held.

The screw tightening member may have a screw tightening hole having a diameter smaller than the outer diameter of the adjustment screw, and the diameter of the screw tightening member may be increased by tightening the adjustment screw to be fixed to the hole of the tripping structure. preferable. Moreover, it is preferable to use a tamper-proof screw as the adjustment screw.

The circuit breaker according to the present invention has a U-shaped hole portion of a tripping structure that constitutes a metal tripping mechanism portion, and a protrusion that engages with a vertical surface below the hole portion at a lower end portion. In addition, since a screw tightening member made of synthetic resin is attached and the bimetal adjustment screw is held on this screw tightening member, the screw tightening member viscosity is not used without using a conventional screw loosening prevention material. The adjustment screw can be fixed by Therefore, the assembling work can be simplified, and the IT characteristic can be adjusted as in the conventional case.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall view of a circuit breaker according to the present invention, and FIG. 2 is a perspective view of a main part thereof. Reference numeral 1 denotes a metal tripping structure which also serves as a tripping piece, and 2 denotes a U-shaped fixed iron piece provided to face the tripping structure 1. A tripping mechanism 30 made of metal is constituted by the tripping structure 1, the fixed iron piece 2, the bimetal 5 described later, and the like. The lower end of the tripping structure 1 is elastically supported by the base 4 of the fixed iron piece 2 via the return spring 3, and has a structure that can be adsorbed by the fixed iron piece 2. The upper end of the tripping structure 1 is bent horizontally and further downward, and an adjustment screw 6 for adjusting a gap with the bimetal 5 is attached to this portion.

  The mounting structure of the adjusting screw 6 that is the main part of the present invention will be described in detail later, but the overall structure will be described briefly first. Reference numeral 7 denotes a movable contact having a movable contact 8 at the tip. When the pressing piece 10 that moves up and down in conjunction with the handle 9 is lowered, the movable contact 7 is pushed down, and the movable contact 8 comes into contact with the fixed contact 11 and turns on. It becomes a state. The bimetal 5 is provided inside the fixed iron piece 2 so that the current guided from the power supply side terminal 12 via the stranded wire 13 flows from the upper part of the bimetal 5 to the movable contact 7 via the fixed iron piece 2. It has become. When the contact is on, the current flows to the fixed contact 14 and the load side terminal 15.

  A link 16 and a latch 17 are provided at the lower portion of the handle 9, and the tip of the latch 17 is attached to an engagement hole 18 formed in the tripping structure 1. Therefore, when the upper part of the tripping structure 1 is moved away from the tip of the latch 17 by the bimetal 5 or the fixed iron piece 3, the latch 17 is released downward, and the movable contact 7 is moved upward by the tripping mechanism. The contact is turned off as in the conventional case.

  As shown in FIGS. 3 and 4, in the present invention, a synthetic resin screw fastening member 19 is attached to the tripping structure 1 constituting the metal tripping mechanism 30, and this screw fastening member. Reference numeral 19 denotes a bimetal adjusting screw 6. In this embodiment, a U-shaped hole 20 is provided in a portion that hangs downward from the upper end of the tripping structure 1, and the screw-fastening member 19 made of synthetic resin is provided in the U-shaped hole 20. It has a shape that can be fitted in from the front. The material of the screw fastening member 19 is preferably a resin having an appropriate viscosity such as polyacetal.

  A screw tightening hole 21 is formed substantially at the center of the screw tightening member 19. The position is preferably matched with the center of curvature at the bottom of the U-shaped hole 20. The screw tightening hole 21 has a slightly smaller diameter than the outer diameter of the adjusting screw 6, and the screw tightening member 19 is expanded in diameter by tightening the adjusting screw 6 in the screw tightening hole 21 as shown in FIG. It is surely fixed to the hole 20 of the tripping structure 1.

  In addition, as shown in FIG. 5, it is preferable that the front end of the screw fastening member 19 is divided into two parts to give elasticity, or the engaging claw 22 is formed at the front end. Moreover, as shown in FIG. 6, the unevenness | corrugation 23 can be formed in the bottom part of the hole 20 of the tripping structure 1, and the screw fastening member 19 can be fixed more reliably. Further, it is preferable that the protrusion 24 is suspended from the lower end portion of the screw tightening member 19 and the front surface thereof is engaged with the vertical surface 25 at the lower portion of the hole portion 20 so as to position the tripping structure 1. In addition, since the present invention has a structure that does not apply a screw loosening prevention material, it can be changed after adjustment by anyone other than the operator who performs the adjustment work. It is preferable to use a tamper-proof screw so that it cannot be adjusted except by a dedicated tool.

  In order to assemble the circuit breaker of the present invention configured as described above, first, the bimetal 5 and the tripping structure 1 are attached to the base 4 of the fixed iron piece 2 and then combined with the hole 20 of the tripping structure 1. The resin screw tightening member 19 is fitted, and the adjustment screw 6 is tightened. As a result, the screw fastening member 19 is fixed to the hole 20 of the tripping structure 1 and holds the adjustment screw 6. Then, temporary adjustment of the bimetal 5 is performed, and the bimetal 5 is completed as a part of the tripping mechanism unit 30.

  Then, it is assembled in a case together with other parts, and finally an IT characteristic test is performed. In this test, the adjustment screw 6 is moved forward and backward to change the gap with the bimetal 5 and readjust the IT characteristic for those outside the standard range. The adjustment screw 6 is held by a screw fastening member 19 made of synthetic resin, and is securely held at that position even after readjustment. Therefore, it is not necessary to apply a screw loosening prevention material as in the prior art, and the adjustment screw 6 can be easily and reliably attached to the metal tripping mechanism 30.

1 is an overall view of a circuit breaker for wiring according to the present invention. It is a perspective view of the principal part. It is a perspective view of the state where the adjustment screw was attached to the tripping structure. FIG. 4 is an exploded perspective view of FIG. 3. It is sectional drawing which shows the procedure which attaches an adjustment screw to a tripping structure. It is a partial expansion perspective view which shows other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal trip structure 2 Fixed iron piece 3 Return spring 4 Base of fixed iron piece 5 Bimetal 6 Adjustment screw 7 Movable contact 8 Movable contact 9 Handle 10 Pressing piece 11 Fixed contact 12 Power supply side terminal 13 Strand 14 Fixed contact 15 Load side terminal 16 Link 17 Latch 18 Engagement hole 19 Screw tightening member 20 made of synthetic resin Hole 21 Screw tightening hole 22 Engagement claw 23 Concavity and convexity 24 Projection 25 Vertical surface 30 Metal tripping mechanism

Claims (3)

In the thermal trip type circuit breaker, a U-shaped hole is formed in a portion that hangs downward from the upper end of the tripping structure constituting the metal tripping mechanism , and the lower end is formed with the U-shaped hole. A synthetic resin screw tightening member provided with a protrusion to be engaged with a vertical surface below the hole portion is fitted into the hole portion, and a bimetal adjusting screw is held by the screw tightening member. Circuit breaker. The screw tightening member is provided with a screw tightening hole having a smaller diameter than the outer diameter of the adjustment screw, the diameter is increased by tightening the adjustment screw, and the screw tightening member is fixed to the hole of the tripping structure. The circuit breaker for wiring according to claim 1. The circuit breaker according to claim 1, wherein a tamper-proof screw is used as the adjustment screw.

Images