Adjustable electromagnetic release

An apparatus having a conductor passing through a magnetic yoke and is mounted on the bracket, in which the magnetic yoke is fixed on the bracket as well. Above the conductor, a shaft is mounted on the top of the bracket. A push rod is mounted on the shaft and rotates with the shaft about the bracket. An armature, spaced apart from the magnetic yoke, is fixed on the push rod. Adjusting mechanisms are mounted on both sides of the shaft between the push rod and the bracket. Within the adjusting mechanism, a torsion spring is around the shaft. An adjusting rod is provided with a plurality of adjusting surfaces which makes contact with the adjusting mechanism. A spring force of the torsion spring enables the push rod to rotate towards a direction which makes the armature and the magnetic yoke separate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the electromagnetic release field, more particularly, relates to an adjustable electromagnetic release for large capacity circuit breakers.

2. The Related Art

Circuit breakers are electrical apparatuses for cutting off fault current such as overload current or short circuit current in circuits so as to protect circuit loads. The circuit breakers cut off the short circuit current via releases. The releases for cutting off short circuit current mainly include electromagnetic releases and electronic releases.

Usually, the releases are required to have different protection scopes in different working environments. Such requirements mean that the releases shall have adjustment abilities so as to satisfy different scales of short circuit current.FIG. 1illustrates the structure of an electromagnetic release in the prior art. As shown inFIG. 1, according to the existing electromagnetic release, an air gap of an electromagnet is reduced via adjustment of an armature. When adjusting the air gap, a reaction spring is stretched and a resistant force of the spring is enlarged meanwhile. Therefore, there are two variables existed in the adjustment, when the initial attraction force enlarges, the initial reaction force enlarges as well. Such an adjustment mode is detrimental to the release rate adjustment of the release. This adjustment mode has low accuracy, sometimes it is not able to obtain the required release rate. Further, when adjusting the air gap, the required adjusting force may be very large due to the function of the reaction spring force, which may cause the adjustment be very difficult. If the material is not strong enough, the adjusting components may be damaged and will cause the circuit breaker be not adjustable.

SUMMARY

The present invention discloses an adjustable electromagnetic release with single variable adjustment ability.

According to an embodiment of the present invention, an adjustable electromagnetic release is disclosed. The adjustable electromagnetic release comprises: an armature, a magnetic yoke, a push rod, a conductor, a blocking piece, an adjusting piece, a shaft, an adjusting screw, a bracket, an adjusting rod and a torsion spring. The magnetic yoke is fixed on the bracket, the conductor passes through the bracket and the magnetic yoke and is mounted on the bracket. The shaft is mounted on the top of the bracket and is above the conductor, the shaft is rotatable about the bracket. The push rod is mounted on the shaft, the push rod rotates with the shaft about the bracket, the armature is fixed on the push rod, the armature and the magnetic yoke are spaced apart. Two adjusting mechanisms are mounted on the shaft, the two adjusting mechanisms are mounted on both sides of the push rod, and between the push rod and the bracket. The torsion spring is surrounded on the shaft, the torsion spring is positioned within the adjusting mechanism. One pin of the torsion spring is connected to the armature, the adjusting mechanism contacts with the push rod. The adjusting rod is provided with a plurality of adjusting surfaces, the adjusting mechanism contacts with the adjusting surfaces, the adjusting rod is able to move along the longitudinal direction. The spring force of the torsion spring enable the push rod rotates towards a direction which makes the armature and the magnetic yoke separate. When large current passes through the conductor, the armature and the magnetic yoke attract each other under the electromagnetic force. When the electromagnetic force is larger than the spring force, the push rod rotates towards a direction which makes the armature and the magnetic yoke close, the push rod strikes the release mechanism to release and cut off the circuit. The electromagnetic force disappears, the push rod resets under the spring force of the torsion spring.

According to an embodiment, the two adjusting mechanisms are disposed on both ends of the shaft respectively, each adjusting mechanism comprises a blocking piece and an adjusting piece. The blocking piece comprises a first plate and a second plate which are perpendicular to each other. The first plate is provided with an obround hole, the second plate is provided with a first shaft hole. The adjusting piece comprises a first side wall, a second side wall and a connecting wall which connects the first side wall and the second side wall. The first side wall has an extension section extending upwards, the first side wall is provided with a second shaft hole. A first arm is provided at the bottom of the extension section, the first arm contacts with the push rod and pushes the push rod. A second arm is provided at the top of the extension section. The second side wall is provided with a third shaft hole. The second shaft hole and the third shaft hole align to each other. The connecting wall is provided with a threaded hole.

According to an embodiment, the blocking piece is assembled with the adjusting piece, the second plate of the blocking piece is close to the inner side of the second side wall of the adjusting piece, the first shaft hole aligns to the third shaft hole, the shaft passes through the first shaft hole, the second shaft hole and the third shaft hole. The adjusting screw passes through the obround hole and the threaded hole, one end of the adjusting screw is screwed on the threaded hole, the adjusting screw is able to move in the obround hole, the blocking piece is able to rotate about the adjusting piece.

According to an embodiment, the outer side of the second side wall of the adjusting piece is close to the bracket, the outer side of the first side wall of the adjusting piece is close to the push rod.

According to an embodiment, the torsion spring is positioned between the second plate of the blocking piece and the first side wall of the adjusting piece. One pin of the torsion spring is connected to the inner side of the blocking piece, the other pin of the torsion spring is connected to a lower portion of the armature.

According to an embodiment, the adjusting rod is provided with a plurality of adjusting surfaces, the plurality of adjusting surfaces are arranged in pairs and are inclined. Two second arms of two adjusting pieces in two adjusting mechanisms are pressed on a pair of the adjusting surfaces.

According to an embodiment, the adjusting rod is provides with a gear rack, the gear rack enables the movement of the adjusting rod along the longitudinal direction.

When adjusting an instantaneous electromagnetic release rate of the electromagnetic release, the adjustable electromagnetic release of the present invention only adjusts the air gap as a single variable. The adjustable electromagnetic release has a small reaction spring force, a small volume and requires a small adjusting force.

DETAILED DESCRIPTION OF EMBODIMENTS

The present invention discloses an adjustable electromagnetic release. As shown inFIG. 2, the adjustable electromagnetic release comprises: an armature101, a magnetic yoke102, a push rod103, a conductor104, a blocking piece105, an adjusting piece106, a shaft107, an adjusting screw108, a bracket109, an adjusting rod110and a torsion spring120.

As shown inFIG. 3,FIG. 3illustrates the structure of the electromagnet. The magnetic yoke102is fixed on the bracket109. In an embodiment, the magnetic yoke102is fixed on the bracket109through rivets. The conductor104passes through the bracket109and the magnetic yoke102and is mounted on the bracket109. The shaft107is mounted on the top of the bracket109and is above the conductor104. The shaft107is rotatable about the bracket109. The push rod103is mounted on the shaft107. The push rod103rotates with the shaft107about the bracket109. The armature101is fixed on the push rod103, and the armature101and the magnetic yoke102are spaced apart. Two adjusting mechanisms are mounted on the shaft107. The two adjusting mechanisms are mounted on both sides of the push rod103, and between the push rod103and the bracket109. The torsion spring120is surrounded on the shaft107, the torsion spring120is positioned within the adjusting mechanism. One pin of the torsion spring is connected to the armature101. The adjusting mechanism contacts with the push rod103.

As shown inFIG. 4,FIG. 4illustrates the structure of the adjusting mechanism. The two adjusting mechanisms are disposed on both ends of the shaft107, respectively. Each adjusting mechanism comprises a blocking piece105and an adjusting piece106. Further referring toFIG. 5,FIG. 5illustrates the structure of the blocking piece. The blocking piece105comprises a first plate151and a second plate152which are perpendicular to each other. The first plate151is provided with an obround hole111. The second plate152is provided with a first shaft hole153. As shown inFIG. 6,FIG. 6illustrates the structure of the adjusting piece. The adjusting piece106comprises a first side wall161, a second side wall162and a connecting wall163which connects the first side wall and the second side wall. The first side wall161has an extension section164extending upwards. The first side wall161is provided with a second shaft hole165. A first arm112is provided at the bottom of the extension section164, the first arm112contacts with the push rod103and pushes the push rod103. A second arm114is provided at the top of the extension section164. The second side wall162is provided with a third shaft hole166. The second shaft hole165and the third shaft hole166align to each other. The connecting wall163is provided with a threaded hole113. Referring back toFIG. 4, the blocking piece105is assembled with the adjusting piece106. The second plate152of the blocking piece105is close to the inner side of the second side wall162of the adjusting piece106. The first shaft hole153aligns to the third shaft hole166. The shaft107passes through the first shaft hole, the second shaft hole and the third shaft hole. The adjusting screw108passes through the obround hole111and the threaded hole113. One end of the adjusting screw108is screwed on the threaded hole113. The adjusting screw108is able to move in the obround hole111. The blocking piece105is able to rotate about the adjusting piece106. Referring back toFIG. 3, the outer side of the second side wall162of the adjusting piece106is close to the bracket109. The outer side of the first side wall161of the adjusting piece106is close to the push rod103.

The torsion spring120is positioned between the second plate152of the blocking piece105and the first side wall161of the adjusting piece106. One pin of the torsion spring120is connected to the inner side of the blocking piece105, the other pin of the torsion spring120is connected to a lower portion of the armature101.

As shown inFIG. 7,FIG. 7illustrates the structure of the adjusting rod. The adjusting rod110is provided with a plurality of adjusting surfaces115. The adjusting mechanism contacts with the adjusting surfaces115. The adjusting rod110is able to move along the longitudinal direction. The plurality of adjusting surfaces115are arranged in pairs and are inclined. The second arms114of the adjusting pieces106in two adjusting mechanisms (that is, two second arms114) are pressed on a pair of the adjusting surfaces115. The adjusting rod110is provided with a gear rack116, which enables the movement of the adjusting rod110along the longitudinal direction.

The spring force of the torsion spring120enables the push rod103to rotate towards a direction which makes the armature101and the magnetic yoke102separate. When large current passes through the conductor, the armature101and the magnetic yoke102attract each other under the electromagnetic force. When the electromagnetic force is larger than the spring force, the push rod103rotates towards a direction which makes the armature101and the magnetic yoke102close. The push rod103strikes the release mechanism to release and cut off the circuit, the electromagnetic force disappears, the push rod103resets under the spring force of the torsion spring120.

The working principle of the adjustable electromagnetic release is described hereafter. The torsion spring120is surrounded on the shaft107and positioned between the adjusting piece106and the blocking piece105. One pin of the torsion spring120is connected to a lower portion of the armature101and the other pin of the torsion spring120is connected to the inner side of the blocking piece105. The armature101and the push rod103may be regarded as an entirety as the armature101and the push rod103are relatively fixed. The armature101and the push rod103receive a torque from the torsion spring120. The other pin of the torsion spring120is connected to the inner side of the blocking piece105, so the blocking piece105receives a torque which makes the blocking piece105rotate outward. The torque was transmitted to the adjusting screw108from the blocking piece105through the obround hole111. The blocking piece105is close against and pressed on the adjusting screw108. The adjusting screw108is connected to the adjusting piece106through threaded connection, so the adjusting screw108and the adjusting piece106may be regarded as an entirety. When the adjusting screw108is fixed to a particular position, the adjusting piece106and the blocking piece105may be regarded as an entirety as well. The adjusting piece106and the blocking piece105form the adjusting mechanism. The adjusting mechanism as a whole receives a torque from the torsion spring120. The adjusting piece106and the push rod103are arranged on a same shaft, the shaft107. The adjusting piece106and the push rod103have the same rotation center, but the torque direction of the adjusting piece106and the push rod103are opposite. The first arm112of the adjusting piece106contacts with the push rod103and make the adjusting piece106and the push rod103to be an entirety. The spring force of the torsion spring120becomes an internal force and makes the entirety relatively fixed. The two adjusting pieces, the two blocking pieces and the two torsion springs are bilateral symmetric, respectively.

When the magnetic yoke102is mounted on the bracket109, under the function of a reaction spring (the reaction spring is not shown in the drawings), the adjusting mechanism as a whole is pressed on the adjusting rod110. As shown inFIG. 2, the second arms114of the adjusting pieces106are pressed on the adjusting surfaces115of the adjusting rod110. The adjusting surfaces115are inclined and arranged in pairs. One pair of the adjusting surfaces115corresponds to two second arms114. As shown inFIG. 7, the adjusting rod110is mounted on an appropriate position of the release and the adjusting rod110may only move along its longitudinal direction. During the movement of the adjusting rod110, the second arm114of the adjusting piece106is always pressed on the adjusting surface115due to the function of the reaction spring. The contact position of the second arm114and the adjusting surface115is determined by the shape of the adjusting surface115. The armature, the push rod and the adjusting mechanism rotate about the shaft107as an entirety to realize the adjustment of the air gap between the armature101and the magnetic yoke102. During the rotating procedure, the spring force of the torsion spring120is an internal force and the spring force remains unchanged.

When large current passes through the conductor104, the armature101and the magnetic yoke102attract each other under the function of the magnetic field. The armature101and the push rod103rotate about the shaft107towards a direction close to the magnetic yoke102. The adjusting piece106follows the armature101to rotate as the adjusting piece106is pressed on the adjusting rod110. One pin of the torsion spring120is pressed down by the armature101and the other pin of the torsion spring120is fixed in the adjusting mechanism. The spring force of the torsion spring120forms a reaction force to the armature101. The armature101rotates under the electromagnetic attraction force and drives the push rod103to strike the release mechanism, so as to break the circuit breaker. When the circuit breaker is open, the electromagnetic force disappears and the torsion spring120drives the armature101and the push rod103to reset.

The initial reaction force to the armature101is generated by the torsion force of the torsion spring120. The torsion force of the torsion spring120may be adjusted via the adjustment of the adjusting screw108. By adjusting the adjusting screw108to change the screwed length which is screwed into the adjusting piece106, the blocking piece105may rotate and drive the pin of the torsion spring120to rotate, then the initial reaction force of the electromagnet is adjusted. While adjusting the air gap of the electromagnet, the reaction force remains unchanged. Therefore, only one variable is adjusted and accuracy of the adjustment is significantly increased.

When the adjusting rod110is moving, the adjusting rod110only receives a friction force from the adjusting piece106. The friction force is associated with the spring force of the spring which is in contact with the magnetic yoke. As the spring force is only a “pre pressure” which makes the adjusting piece pressed on the adjusting rod, the spring force may be a relatively small force, thus the friction force may also be small, which means only a small adjusting force is required to adjust the adjusting rod110. A small adjusting force may bring great convenience to the users and avoid potential damages to the adjusting components. The gear rack116shown inFIG. 7may be used to adjust the adjusting rod110. It should be noticed that the adjusting mechanism of the adjusting rod110shall not be limited to the gear rack116, other well-known mechanisms may be used to the adjusting rod110as well.

When adjusting an instantaneous electromagnetic release rate of the electromagnetic release, the adjustable electromagnetic release of the present invention only adjusts the air gap as a single variable. The adjustable electromagnetic release has a small reaction spring force, a small volume and requires a small adjusting force.

The above embodiments are provided to those skilled in the art to realize or use the invention, under the condition that various modifications or changes being made by those skilled in the art without departing the spirit and principle of the invention, the above embodiments may be modified and changed variously, therefore the protection scope of the invention is not limited by the above embodiments, rather, it should conform to the maximum scope of the innovative features mentioned in the Claims.