JPH0810920Y2 - Circuit breaker trip crossbar - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a trip crossbar forming a part of a trip mechanism in a small circuit breaker such as a circuit breaker for wiring.

[Prior art]

FIG. 12 shows a general structure of a circuit breaker for three-pole wiring in which components are housed in an outer casing made of a molded resin, which comprises a case 1 and a cover 2. The figure is a vertical cross-sectional view of the central pole portion in the closed state, and the current flows through the path of the power source side terminal 3, fixed contact 4, movable contact 5, lead wire 6, overcurrent trip device 7 and load side terminal 8. . The movable contactor 5 is driven to be opened and closed by the opening / closing mechanism 9. The opening / closing mechanism 9 is reset by latching a latch 11 supported by a frame 10 having side plates on both sides of the movable contactor 5 to a latch receiver 12. Is held in a state. The latch receiver 12 receives a force from the latch 11 in the clockwise direction in the figure, but the latch 14 of the trip crossbar 13 that engages with the back surface of the latch receiver 12 is provided.
The rotation is blocked by. When an overload current or a short-circuit current flows in the state shown in the drawing, the overcurrent trip device 7 strikes the trip crossbar 13 to rotate it counterclockwise, releasing the engagement between the pawl 14 and the latch receiver 12. As a result, the latch receiver 12 rotates clockwise, the latch 11 is no longer locked, and the movable contact 5 is opened by the operation of the opening / closing mechanism 9. FIG. 13 shows a conventional configuration of the trip crossbar 13 described above. (A) is a front view of the main part as seen from the direction of arrow P in FIG. 12, and (B) is a sectional view taken along the line BB. is there. In the figure, the trip crossbar 13 is composed of a round bar-shaped insulating bar 13a that straddles each pole and a thrust plate 13b for each pole that receives the operating force of the overcurrent trip device 7, and is formed of a molding resin. . A claw made of an iron plate with a front end formed in an arc shape
The core metal 14 is press-fitted into the core metal 15, and the core metal 15 is embedded in the insulating bar 13a when the trip crossbar 13 is molded and fixed to the trip crossbar 13. The trip crossbar 13 is rotatably attached to the case 1 by inserting the small-diameter shaft portions 13c that integrally project at both ends of the insulating bar 13a into the support fittings 16 that are press-fitted into the grooves of the left and right side walls 1a of the case 1. It is supported. FIG. 14 shows another conventional structure for fixing the claw 14 to the trip crossbar 13. The core metal 15 into which the claw 14 is press-fitted is shown.
Is dropped into the groove 17 of the insulating bar 13a from above, and is fixed by two positioning pins 18 left and right driven into this groove.

[Problems to be solved by the device]

However, such a conventional trip crossbar 13 has the following problems. (1) The trip crossbar 13 is supported by the case 1 through the support metal fittings 16, but the trip crossbar 13 and the case 1
Since and are resin molded products, the positional accuracy of the trip crossbar 13 by these combinations is low. Further, the support fitting 16 is held by the cover 2, but if there is a gap between the upper surface of the support fitting 16 and the lower surface of the cover 2, the support fitting is lifted when the trip crossbar 13 is rotated. Therefore, the positional relationship between the claw 14 and the latch receiver 12 or the positional relationship between the veneer 13b and the operating portion of the overcurrent trip device 7 (the operating end of the armature 7a and the bimetal 7b) varies, and the tripping characteristic Becomes unstable. (2) Make sure that the trip crossbar 13 does not generate a rotational moment due to the force from the latch receiver 12
The line of action of the force F exerted on the claw 14 from the is designed so as to pass through the center of the rotating shaft of the trip crossbar 13 as shown in FIG. 13 (B). Since it is fixed to the insulating bar 13a by embedded molding or a positioning pin 18, misalignment is likely to occur between the insulating bar 13a and the integrally molded shaft portion 13c, and there is a risk of accidental trip due to vibration or shock. (3) The work of press-fitting the claw 14 into the cored bar 15 and further embedding it and fixing it with the positioning pin 18 is not suitable for mass production because automation is difficult. The present invention addresses such a problem, and an object thereof is to provide a trip crossbar for a circuit breaker which has a high positional accuracy after assembly, a stable operation, and is easy to automate. .

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the invention is such that a frame having side plates on both sides of a movable contact of a central pole supports a latch of an opening / closing mechanism and a latch receiver for locking the latch, and each of the back surfaces of the latch receiver has a latch. In a circuit breaker in which the pawls of a freely rotatable trip crossbar that straddles poles are engaged at the front end surface that is formed in an arc shape, fix the U-shaped mounting brackets with arms on the left and right on the trip crossbar. , The one end of the arm is formed integrally with the claw so as to extend forward,
The trip crossbar is rotatably supported on the side plate of the frame via pins inserted into the left and right arms.

[Action]

Since the frame of the opening / closing mechanism and the metal fittings for the trip crossbar can be molded and drilled by pressing, the dimensional accuracy is high. Therefore, according to these combinations, the positional accuracy of the trip crossbar becomes very high. Further, since the claw is formed integrally with the mounting member, complicated work for fixing the claw is not necessary, and the accuracy of alignment of the trip crossbar with respect to the rotation axis is improved.

【Example】

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted. 1 to 3 show an embodiment of the present invention, FIG. 1 is a perspective view of a trip crossbar, FIG. 2A is a partially enlarged front view thereof, and FIG. Sectional view taken along line B,
FIG. 3 is a perspective view of the frame. In FIG. 1, reference numeral 20 denotes a U-shaped mounting metal member which is press-molded from an iron plate and has arms standing upright to the left and right, and a pin hole 22 for inserting a pin 21 is punched in each arm. A claw 23 is integrally formed at the tip of the right arm in the figure so as to extend forward. The front end surface of the claw 23 that engages with the back surface of the latch receiver 12 is formed in an arc shape, and the center of this arc is accurately located on a horizontal line passing through the center of the pin hole 22. That is, the line of action of the force acting from the rear surface of the latch receiver 12 which is vertical in the reset state of the circuit breaker passes through the center. The trip crossbar 24 is composed of an insulating bar 24a extending over each pole of the circuit breaker, and a veneer 24b facing the overcurrent trip device 7 for each pole, as in the conventional case. A rectangular groove 25 conforming to the contour of the mounting member 20 is cut out on the front side of the portion, and the mounting member 20 housed in this groove 25 is fixed to the horizontal bottom of the groove 25 by a rivet 26. Also, on the front side of the right half of the figure of the insulating bar 24a,
A groove 27 having a fan-shaped cross section from the end face to the groove 25 is formed by cutting out. The cross section of the groove 27 expands slightly before the groove 25, and a spring piece 28 is integrally formed on the bottom of the groove 27 so as to stand up. FIG. 3 is a perspective view of the frame 29 supporting the opening / closing mechanism as seen from the load side of the circuit breaker. 29a is a pin hole of the latch 11,
9b is a pin hole of the latch receiver 12. This frame 29 has an arm 29c extending from the pin hole 29b to the load side.
A pin hole 29d for inserting the pin 21 that supports the trip crossbar 24 is provided at the tip of c. Now, in order to support the trip crossbar 24 on the frame 29, it is necessary to mount the mounting bracket 2 between the left and right arms 29c, 29c of the frame 29.
Position 0 and align pin holes 22 and 29d. And
As shown in FIG. 1, the pin 21 is housed in the groove 27 in the direction of arrow Q and then inserted in the pin holes 22 and 29d in the direction of arrow R. At that time, as shown by the chain double-dashed line in FIG. 2, the pin 21 is advanced while pushing down the spring piece 28 by elastic deformation. When the tip of the pin 21 hits the left end of the groove 25 in the figure, the pin 21 moves toward the spring piece 28.
The spring piece 28 that has passed over and returned has a retaining effect. According to such a configuration, since the trip crossbar 24 is supported by the combination of the press-formed products of the mounting bracket 20 and the frame 29, the positional relationship between the claw 23 and the latch receiver 12,
The positional relationship between the veneer 24b and the overcurrent trip device 7 is accurately determined. Further, since the tip arc of the claw 23 and the center of the rotary shaft of the trip crossbar 24 (the center of the pin hole 22) are simultaneously machined on the same mounting bracket 20 by pressing, the positional relationship between the two is accurately determined. There is no risk that a rotational moment will act on the trip crossbar 24 due to the force from the latch receiver 12. Further, since the claw 23 is formed integrally with the fitting 20, the special work for fixing the claw 23 is unnecessary. 4 and 5 show another embodiment of the retaining structure of the pin 21. Instead of providing the spring piece 28, the rear end 21a of the pin 21 inserted through the groove 27 is shown in FIG. It is bent to. In FIG. 4, the groove 27 is provided only on one side (right side in the figure), but when the groove 27 is on both sides, as shown in FIG. 21b
Is formed, and the tip 21a is bent after being inserted from the left side of the drawing. With such a configuration, the pin 21 can be prevented from coming off even when the trip crossbar 24 is made of a material having low elasticity such as a thermosetting resin. 7 and 8 show still another embodiment of the pin 21 retaining structure. In this case, in particular, as shown in detail in FIG. 8, a narrow portion is formed in the middle of the groove 27 and slightly before the groove 25.
30 is provided, and a pair of blind holes 31 facing each other are formed in this portion from above and below. Therefore, after inserting the pin 21, as shown in FIG. 9, the bottom portion 31a of the blind hole 31 is plastically deformed and pushed out to close the narrow portion 30 to prevent the pin 21 from coming off. According to such a structure, the pin 21 can be prevented from coming off very easily in the trip crossbar which is also made of a material having low elasticity. FIGS. 10 and 11 show an embodiment in which the work of extruding the blind hole 31 is facilitated, and a small through hole 31b is provided in the bottom portion 31a of the blind hole 31. This allows plastic deformation with a smaller force. FIG. 11 shows the state after extrusion.

[Effect of device]

According to this invention, since the trip crossbar is supported by a combination of press-formed products capable of precision processing, the positional relationship with related parts is accurate, and the tripping property is improved. In particular, the claw integrally formed on the tip of the arm of the mounting bracket can be pressed at the same time as the pin hole of the arm, so the positional relationship between the rotation center of the mounting bracket and the claw is accurately determined, and the latch receiver acts on the claw. As a result, the action line of the applied force can be made to accurately pass through the center of rotation, and as a result, unnecessary trip moments do not act on the trip crossbar, the tripping characteristics are stable, and mistakes due to shocks during opening and closing. The risk of trips is reduced. Further, since the claws are integrally formed with the mounting metal fittings, the manufacturing process is simplified and the assembling work can be automated.

[Brief description of drawings]

FIG. 1 is a perspective view of a trip crossbar in an embodiment of the present invention, FIG. 2 (A) is a partially enlarged front view of FIG. 1, and FIG. 2 (B) is a sectional view taken along line BB thereof. 3 is a perspective view of a frame according to an embodiment of the present invention, FIG. 4 is a perspective view of a trip crossbar according to another embodiment of the present invention, and FIG. 5 is a partially enlarged front view of FIG. FIG. 6 is a front view of a main part of the modified example of FIG. 5, FIG. 7 is a perspective view of a trip crossbar in yet another embodiment, and FIG. 8A is a partially enlarged front view of FIG. FIG. 8 (B) is a sectional view taken along the line BB, FIG. 9 (A) is a front view in which the bottom portion of the blind hole in FIG. 8 is pushed out, and FIG. 9 (B) is its BB. A sectional view taken along the line, FIG. 10 (A) is a front view of a main portion of a modified example of the embodiment shown in FIG. 7, and FIG. 10 (B) is a sectional view taken along the line BB.
FIG. 11 (A) is a front view of the bottom of the hole in FIG. 10 extruded, FIG. 11 (B) is a cross-sectional view taken along the line BB, and FIG.
The figure is a vertical cross-sectional view of the central pole portion for explaining the general configuration of a conventional circuit breaker, FIG. 13 (A) is a front view of the main part as seen from the direction of arrow P in FIG. 12, and FIG. ) Is a sectional view taken along the line BB, FIG. 14 (A) is a view corresponding to FIG. 13 (A) of a different conventional example, and FIG. 14 (B) is a sectional view taken along the line BB. Is. 20 …… Mounting bracket, 21 …… Pin, 23 …… Claw, 24 …… Trip crossbar, 29 …… Frame.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Asakawa 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (56) Reference JP 57-152635 (JP, A) Flat 1-79247 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A latch having an opening / closing mechanism and a latch receiver for locking the latch are supported by a frame having side plates on both sides of a movable contact of the central pole, and the back surface of the latch receiver extends over each pole. In a circuit breaker in which the claws of a free trip crossbar are engaged at the front end surface formed in an arc shape, a U-shaped mounting bracket having left and right arms is fixed to the trip crossbar, and one of the arms of one of the arms is fixed. The pawl is integrally formed so as to extend forward, and the trip crossbar is rotatably supported by the side plate of the frame through a pin inserted into the left and right arms. Circuit breaker trip crossbar.