JPH039239Y2 - - Google Patents

Description

[Detailed description of the invention] Purpose of the invention (field of industrial application) This invention relates to a fuse tube for a circuit breaker.

(Prior art) Fig. 4 shows an air circuit breaker with ground protection. Conventionally, this type of air circuit breaker has used a fuse tube F that houses a discharge type fuse A, which can cause short-circuit accidents, etc. When the fusible body of the ejection type fuse is fused, the stored force of the coil spring is released and the ejection tube 8 is released.
is ejected, the ejection tube 8 comes into contact with the interlocking insulator tube 20 with the protrusion 9, and when the swing lever 21 is rotated, the push lever 22 breaks the toggle lock mechanism of the operating mechanism M, thereby The elevating frame body 23 is moved downward by the weight of the movable insulator body 24, etc., and both the upper and lower contact blades 27 of the fuse tube F are separated from the fixed electrode 26 housed in the main body insulator 25 at the same time to open the three phases. or,
The lead wire is pulled out from inside the insulating cylinder by the ejecting force of the ejecting cylinder 8 and the gas pressure at the time of interruption.

(Problem that the invention aims to solve) However, due to the gas pressure generated when the discharge type fuse blows due to short-circuit current, etc., and the ejection of the ejection tube biased by the coil spring, the lead wire is forced out of the insulating tube. The lead wire is pulled out well and comes off the groove 8b of the ejection tube 8 shown in FIG. The broken end of the lead wire that touched from the side comes into contact with the breaker support, etc., causing a new fault.
This caused a short-circuit accident, which caused the circuit to reclose, albeit momentarily, and the short-circuit current could cause thermal damage to porcelain, etc.

(Means for Solving the Problems) This invention was made to solve the above-mentioned problems, and the projecting tube is provided with a part to prevent the lead wire from flying up when the fuse blows.

(Function) Even if the lead wire is forcefully pulled out from the inside of the insulating cylinder and jumped up by the melting of the fusible body by the above-mentioned means, the lead wire inserted into the lead wire insertion hole will not fly out of the ejecting cylinder. It is folded back by the roll-up prevention part. Therefore, since the lead wire passes through the lower end of the protruding ejection tube, the broken end of the lead wire does not reach the upper contact blade, and the broken end of the lead wire does not fly. The range of upward inversion is different from the conventional one, and is a limited and narrow range.

(Example) An example embodying this invention will be described below with reference to FIGS. 1 and 2.

In the figure, reference numeral 1 denotes an insulating tube constituting a fuse tube, and a release type fuse A is installed inside the insulating tube. Reference numeral 2 denotes an upper electrode fitting fixed to the outer periphery of the upper end of the insulating cylinder 1, to which the discharge type fuse A is connected, and a cap 3 for sealing the upper end of the insulating cylinder 1 is screwed and fixed to the upper end of the upper electrode fitting. An upper contact blade 4 is provided to protrude from a part of the surface. Reference numeral 5 denotes a lower electrode fitting fixed slightly below the center of the insulating cylinder 1, and a lower contact blade 6 is protruded from a part of its outer peripheral surface on the same side as the upper contact blade, and a lower contact blade 6 is provided at the lower end. A connecting portion 7 is formed to extend.

Reference numeral 8 denotes a projecting cylinder made of an insulating material that is slidably fitted to the open end of the insulating cylinder 1, and a part of its inner circumferential surface has an expanded outer peripheral edge of the open end of the insulating cylinder 1. An annular locking step 8a is formed to be locked to the formed annular locking step 1a. Reference numeral 9 denotes a protrusion that bulges outward at the lower end of the ejection tube 8 and comes into contact with the interlocking insulator tube 20 of the circuit breaker, through which a lead wire insertion hole 11 is provided. A lead wire B that electrically connects the solution (not shown) and the connecting portion 7 of the lower electrode fitting 5 is inserted. Reference numeral 12 denotes a lead wire jump prevention portion formed at the lower part of the protrusion 9 by the lead wire insertion hole 11, which prevents the lead wire B from blowing up when the fusible material is fused.
The point of curvature when the cut-off end of the fuse tube springs up is set further away from the upper contact blade 4 than in a conventionally configured fuse tube. A fuse terminal fitting 13 is caulked to one end of the lead wire B, and is fastened and fixed to the contact portion 7 by a screw 14.

Reference numeral 16 denotes a cylinder made of an insulating material whose end portion is fixed to the insulating cylinder 1 below the lower electrode fitting 5, and is formed to cover the upper outer periphery of the ejecting cylinder 8. 17 is the inner upper end 16a of the cylindrical body 16
The coil spring is interposed between the locking step portion 8a of the ejecting tube 8, and is held in a stored state by the lead wire B, and the ejecting tube 8 is made elastic by cutting the fusible body. It's starting to work fine.

Now, the operation of the circuit breaker fuse tube constructed as described above will be explained with reference to the drawings.

When an accident such as a short circuit occurs, the fusible material in the release type fuse A is fused and the stored force of the coil spring 17 is released. Then, the lead wire B connected to the fusible body is ejected from the ejection tube 8 which is biased by the coil spring 17.
Then, it is forcefully pulled out from inside the insulating cylinder 1 by the gas pressure. At this time, even if the separated end of the lead wire B inserted into the lead wire insertion hole 11 springs up, it is folded back by the lead wire spring-up preventing portion 12 of the protrusion 9. Therefore, the lead wire B is connected to the ejection tube 8.
By passing through the lower end of the lead wire B, the separated end of the lead wire B becomes far from the upper contact blade 4, and the lead wire B
The range in which the severed end of the blade springs up and inverts is a limited and narrow range. Therefore, unlike conventional circuit breaker fuses in which the ejection tube 8 is not provided with the lead wire spring-up prevention part 12, the separated end of the lead wire B springs up like the lead wire B2 and comes into contact with the upper part. Blade 4
When touched, the circuit recloses, and the porcelain etc. will not be thermally destroyed by causing an accidental current such as a short circuit to flow again. In addition, the range in which the separated end of the lead wire B springs up is limited to a narrow range as in the case of the lead wire B1, and there is no risk of contact with the support of the circuit breaker or the like and causing a new ground fault.

(Another Example) As another example of the first embodiment, as shown in FIG.
2, a diagonal lead wire insertion groove 21a is provided to allow the lead wire B to pass through the lead wire, and a hook-shaped lead wire spring-up prevention portion 12b is formed along the inner periphery of the lead wire insertion hole 11. The wire B may be inserted into the lead wire insertion hole 11 through the lead wire insertion groove 12a. In this case, even if the fusible body is fused and the lead wire B springs up, as in the above embodiment, the lead wire spring-up prevention portion 12b formed in a hook shape
As a result, the lead wire B is folded back like a lead wire B1. Furthermore, when replacing the fuse, there is no need to pass the fuse terminal fitting 13 and the tip of the lead wire B through the lead wire insertion hole 11, and it is easy to replace the fuse by inserting it into the lead wire insertion groove 12a at the folded position of the lead wire B. A new fuse can be installed.

Note that this invention is not limited to the above-mentioned embodiments, and may be modified as desired without departing from the spirit of this invention.

Effects of the invention As detailed above, in the present invention, even if the fusible material is fused due to an accidental current and the lead wire is forcefully pulled out from inside the insulating cylinder and its severed end springs up, the lead wire The range in which the lead wire can be reversed is restricted by the lead wire jump prevention part in the lead wire insertion hole provided in the ejection tube, and the separated end of the lead wire that has sprung up will come into contact with the upper contact blade again or be cut off. This has an excellent effect in that double accidents such as short circuits and ground faults do not occur due to touching the support of the device.

[Brief explanation of drawings]

1 and 2 show a first embodiment, FIG. 1 is a sectional view of a fuse tube for a circuit breaker, FIG. 2 is a bottom end view of the fuse tube for a circuit breaker, and FIG. 3 is a circuit breaker showing another example. FIG. 4 is a side view of an air circuit breaker with ground fault protection, and FIG. 5 is a bottom end view of a conventional circuit breaker fuse. 1...Insulating tube, 2...Upper electrode fitting, 4...Upper contact blade, 5...Lower electrode fitting, 6...Lower contact blade, 8...Ejection tube, 12, 12b...Lead wire splash Climb prevention part, 16...Cylinder body, 17...Coil spring, A...Discharge type fuse, B...Lead wire.

Claims (1)

[Claims for Utility Model Registration] 1. Upper and lower electrode fittings 2, 5 with both upper and lower contact blades 4, 6 protruding from the upper and central parts of the insulating cylinder 1.
Further, a cylinder 16 is fitted to the lower outer periphery of the insulating cylinder 1, and a projecting cylinder 8 is loosely fitted between the cylinder 16 and the insulating cylinder 1 via a coil spring 17 so as to be retractable. A discharge type fuse A having one end electrically connected to the upper electrode metal fitting 2 is arranged in the insulating cylinder 1 for the fuse tube, and a lead wire B led out from the other end of the discharge type fuse A is connected to the insulating tube 1. At the open end position of the insulating cylinder 1, the ejecting cylinder 8 is bent so as to be supported inwardly against the biasing force of the coil spring 17, and electrically connected to a part of the lower electrode 5. The fuse tube for a circuit breaker is characterized in that the ejection tube 8 is provided with a part to prevent the lead wire B from springing up when the ejection type fuse A is blown. 2. The fuse cylinder for a circuit breaker according to claim 1, wherein the spring-up prevention part is the lower wall 12 of the lead wire insertion hole 11 provided at the lower part of the ejection cylinder 8.