Anti-drop contact structure

Abstract

The present invention discloses an anti-drop contact structure, comprising a contact bracket, a torsion spring, a friction wheel, a friction wheel shaft, a support frame, a moving contact, a contact spring, a flexible connection, a copper busbar, a stop screw, a static contact, and a contact shaft; the torsion spring, friction wheel, friction wheel shaft, and moving contact are mounted on the contact bracket, while the contact bracket is mounted on the support frame. Under the action of the torsion spring, the friction wheel can contact the moving contact. The contact structure of the present invention can form a one-way friction clutch structure between the friction wheel and the moving contact after the contact system is closed, so that the moving contact can remain in any repelling position without falling when it is repelled by the electric force, greatly improving the current limiting capacity and breaking capacity of the circuit breaker.

Description

Technical Field

[0001] The invention belongs to the technical field of low-voltage electrical appliances, and in particular relates to an anti-drop contact structure. Background Art

[0002] Current-limiting circuit breakers are an extremely important type of circuit breaker. Before the short-circuit current reaches its peak, the contact system opens in advance to limit the rise of the short-circuit current. The mechanism then operates to open the contact system just in time before the contacts fall back to close again, enabling high-current interruption. The greater the current-limiting capability of a current-limiting circuit breaker, the greater its ultimate interrupting capacity. If the mechanism fails to operate promptly, welding or direct contact burn may occur when the contacts close again after opening, and the circuit breaker will fail to limit the current and break. Therefore, the matching of the opening movement of the circuit breaker's contact system and the timely opening movement of the mechanism is crucial to achieving current limiting and successful interruption.

[0003] Contact drop prevention is one of the most reliable methods for achieving matching between the opening motion of the contact system and the tripping motion of the mechanism. Existing contact drop prevention designs for current-limiting circuit breakers typically employ a method of redirecting the contact spring's force. Specifically, a unique structure is designed where the contact spring applies force. In the normal closed state, the contact spring provides the closing force. When the contacts are pushed apart a certain distance, the contact spring's force changes direction, providing the tripping force and preventing the contacts from dropping.

[0004] However, the fatal flaw of this method is that it requires the contacts to be opened to a large angle to prevent them from falling. Usually, the short-circuit current is not enough to open the contacts to an angle where they cannot fall, so this method fails in most working conditions. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems of existing current limiting circuit breaker contact structures, such as failure to self-lock after small-angle repulsion, resulting in contact drop, and low current limiting capability, and to provide an anti-drop contact structure.

[0006] The technical solution adopted by the present invention to solve its technical problems is: an anti-drop contact structure, including a contact bracket and a support bracket and a moving contact movably mounted on the contact bracket through a contact shaft, a contact spring is arranged between the contact bracket and the moving contact, providing a counterclockwise rotation force for the moving contact, the lower side of the moving contact is connected to the outlet copper bus through a soft connection, the outlet copper bus is provided with a height-adjustable stop screw located below the friction wheel, the top of the moving contact is provided with an arc-shaped friction surface concentric with the contact shaft, a stop surface is provided on the friction surface, a friction wheel and a torsion spring that provides a clockwise rotation force to the friction wheel are installed on the contact bracket through the friction wheel shaft, and the outer edge of the friction wheel is located outside the junction of the friction surface and the stop surface.

[0007] The friction surface of the anti-drop contact structure is a rough surface or a fine-tooth surface.

[0008] The anti-drop contact structure is characterized in that a non-friction surface which is concentric with the arc-shaped friction surface and has a smaller outer diameter is provided on the top of the moving contact. The connection between the arc-shaped friction surface and the non-friction surface forms a stop surface. A guide fillet is provided at the junction, and the fillet radius is R0.2.

[0009] The movable contact of the anti-drop contact structure is composed of a horizontal extension portion and a downward bending portion, and the contact bracket is provided with a top frame portion for limiting the downward bending portion.

[0010] The friction wheel of the anti-drop contact structure is a V-shaped structure composed of two extensions, one extension is suspended in the air, the other extension abuts against one leg of the torsion spring, and the other leg of the torsion spring abuts against the top frame of the contact bracket.

[0011] In the aforementioned anti-drop contact structure, a corner is provided at the bottom end of an extension portion of the friction wheel, and the radius of the corner is less than R0.5, and may be R0.2.

[0012] Compared with the existing known technologies, the technical solution provided by the present invention has the following significant effects:

[0013] The contact structure of the present invention has a unique design of a moving contact and friction wheel structure, so that a one-way friction clutch structure can be formed between the friction wheel and the moving contact after the contact system is closed. As a result, the moving contact can remain in any repelling position without falling during the repelling movement due to the action of electric force, greatly improving the current limiting capacity and breaking capacity of the circuit breaker. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is an axonometric drawing of the present invention;

[0015] Figure 2 This is a schematic diagram of the contact system of the present invention when it is just in contact;

[0016] Figure 3 is a schematic diagram of the contact system of the present invention when closure is completed;

[0017] Figure 4 Schematic diagram of the contact system of the present invention when it is opened;

[0018] Figure 5 is a schematic diagram of the contact system of the present invention when it is disconnected;

[0019] Figure 6 It is a structural schematic diagram of the movable contact of the present invention;

[0020] Figure 7 A schematic structural diagram of the friction wheel of the present invention.

[0021] The figures are marked as follows: 1—contact bracket, 2—torsion spring, 3—friction wheel, 3a—rotating angle, 4—friction wheel shaft, 5—support frame, 6—moving contact, 6a—friction surface, 6b—stop surface, 7—contact spring, 8—flexible connection, 9—outgoing copper bus, 10—stop screw, 11—static contact, 12—contact shaft. DETAILED DESCRIPTION

[0022] In order to further understand the content of the present invention, the present invention is described in detail with reference to the accompanying drawings and embodiments.

[0023] Reference Figure 1 and Figure 2 As shown, the present invention discloses an anti-drop contact structure, including a contact bracket 1, a torsion spring 2, a friction wheel 3, a friction wheel shaft 4, a support frame 5, a moving contact 6, a contact spring 7, a flexible connection 8, an outlet copper bus 9, a stop screw 10, a static contact 11 and a contact shaft 12.

[0024] The movable contact 6 is mounted in the contact support 1 via a contact shaft 12 and can rotate about the shaft. It consists of a horizontal extension that abuts the stationary contact 11 and a downwardly bent portion. A contact spring 7 is mounted between the contact support 1 and the downwardly bent portion of the movable contact 6 and secured to the contact support 1 via a pin. It applies a thrust toward the downwardly bent portion, providing a counterclockwise rotational force for the movable contact 6. The contact support 1 is provided with a top frame portion that limits the downwardly bent portion. The contact support 1 is mounted on a support frame 5 with a P-shaped cross section via the contact shaft 12. It can rotate flexibly to connect and disconnect the horizontal extension of the movable contact 6 with the stationary contact 11. The friction wheel 3 and torsion spring 2 are mounted on the contact support 1 via the friction wheel shaft 4. The torsion spring 2 provides a clockwise rotational force to the friction wheel 3, causing the V-shaped friction wheel 3 to consistently move toward the movable contact 6. The outgoing copper busbar 9 and the downwardly bent portion of the moving contact 6 are connected together by a soft connection 8, and a height-adjustable stop screw 10 is fixedly installed on the outgoing copper busbar 9, which can make the friction wheel 3 and the moving contact 6 in a non-contact state when the contact system is disconnected. The stop screw 10 can adjust the gap between the friction wheel 3 and the moving contact stop surface 6b when the system is opened to between 1 and 2 mm by adjusting the height.

[0025] The torsion spring 2, friction wheel 3, friction wheel shaft 4 and moving contact 6 of the present invention are mounted on the contact bracket 1, and the contact bracket 1 is mounted on the support frame 5. One extension of the friction wheel 3 is suspended in the air, and the other extension abuts against one leg of the torsion spring 2. The other leg of the torsion spring 2 abuts against the top frame of the contact bracket 1. In addition, the right extension of the friction wheel 3 is provided with a corner 3a, and the radius of the corner 3a is less than R0.5, and can be R0.2, such as Figure 7As shown, the friction wheel 3 can contact the moving contact 6 under the action of the torsion spring 2. After the contact system is closed, the contact structure of the present invention can form a one-way friction clutch structure between the friction wheel 3 and the moving contact 6. This allows the moving contact 6 to remain in any repelling position without falling during the repelling movement due to the action of the electric force, greatly improving the current limiting and breaking capabilities of the circuit breaker.

[0026] Reference Figure 6 The top of the moving contact 6 is provided with an arc-shaped friction surface 6a having the same center as the contact shaft 12 and a non-friction surface having an outer diameter smaller than that of the arc-shaped friction surface 6a. The connection between the friction surface 6a and the non-friction surface forms a stop surface 6b. Figure 2 When the contact system is just in contact, that is, the horizontal extension of the moving contact 6 is just in contact with the static contact 11, the moving contact 6 rotates counterclockwise around the contact shaft 12 to the limit position under the action of the contact spring 7 and contacts the top frame of the contact bracket 1. It is restricted by the contact bracket 1 and cannot continue to rotate counterclockwise. The left extension of the friction wheel 3 contacts the stop surface 6b of the moving contact 6. The moving contact 6 is not restricted by the friction wheel 3 and only needs to overcome the force of the contact spring 7 to rotate clockwise around the contact shaft 12.

[0027] Reference Figure 3 When the contact system is closed, that is, the horizontal extension of the moving contact 6 is connected to the static contact 11, the moving contact 6 rotates clockwise around the contact shaft 12 to a certain angle, and the horizontal extension no longer contacts the contact bracket 1, so that the force of the contact spring 7 on the moving contact 6 is transmitted between the moving contact 6 and the static contact 11, thereby causing contact pressure between the moving contact 6 and the static contact 11. At this time, the left extension of the friction wheel 3 is located at the intersection of the friction surface 6a and the stop surface 6b of the moving contact 6, and the intersection is provided with a fillet with a radius of R0.2, and the moving contact 6 can still rotate counterclockwise around the contact shaft 12 by a small angle to ensure that there is contact pressure between the moving contact 6 and the static contact 11.

[0028] Reference Figure 4 When the contact system is repelled, that is, the movable contact 6 rotates clockwise around the contact shaft 12 under the action of electric force, the left extension of the friction wheel 3 contacts the friction surface 6a of the movable contact 6, so that a one-way friction clutch structure is formed between the friction wheel 3 and the movable contact 6. Under the action of friction force, the movable contact 6 can only rotate clockwise but not counterclockwise, so that the movable contact 6 can remain in any repelling position without falling during the repelling movement due to the action of electric force, thereby greatly improving the current limiting capacity and breaking capacity of the circuit breaker.

[0029] Reference Figure 5When the contact system is disconnected, that is, the contact bracket 1 rotates clockwise to the opening position, thereby driving the moving contact 6 to rotate clockwise, and the friction wheel 3 rotates counterclockwise around the friction wheel shaft 4 under the action of the stop screw 10 so that the friction wheel 3 and the moving contact 6 are not in contact. The one-way friction clutch structure is released, and the moving contact 6 rotates counterclockwise around the contact shaft 12 under the action of the contact spring 7 to the limit position and contacts the contact bracket 1.

[0030] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some embodiments of its application. A person skilled in the art may make several modifications and improvements without departing from the inventive concept of the present invention, and all of these modifications and improvements fall within the scope of protection of the present invention.

Claims

1. A contact structure for preventing falling, characterized in that: The invention comprises a contact support (1) and a support frame (5) and a moving contact (6) movably mounted on the contact support (1) via a contact shaft (12), a contact spring (7) being arranged between the contact support (1) and the moving contact (6), the lower side of the moving contact (6) being connected to an outlet copper busbar (9) via a soft connection (8), a height-adjustable stop screw (10) being installed on the outlet copper busbar (9), an arc-shaped friction surface (6a) and a non-friction surface being concentric with the arc-shaped friction surface (6a) and having an outer diameter smaller than that of the arc-shaped friction surface (6a) being arranged on the top of the moving contact (6), the connection portion between the arc-shaped friction surface (6a) and the non-friction surface forming a stop surface (6b), a friction wheel (3) and a torsion spring (2) being mounted on the contact support (1) via a friction wheel shaft (4), the outer edge of the friction wheel (3) being located outside the junction between the friction surface (6a) and the stop surface (6b).

2. The anti-drop contact structure according to claim 1, characterized in that: The friction surface (6a) is a rough surface or a fine-toothed surface.

3. The anti-drop contact structure according to claim 1, characterized in that: The junction is provided with a fillet with a radius R0.

2.

4. The anti-drop contact structure according to claim 1, 2 or 3, characterized in that: The moving contact (6) is composed of a horizontal extension portion and a downward bending portion, and the contact bracket (1) is provided with a top frame portion for limiting the downward bending portion.

5. The anti-drop contact structure according to claim 4, characterized in that: The friction wheel (3) is a V-shaped structure composed of two extensions, one extension is suspended in the air, the other extension abuts against one leg of the torsion spring (2), and the other leg of the torsion spring (2) abuts against the top frame of the contact bracket (1).

6. The anti-drop contact structure according to claim 5, characterized in that: The bottom end of the extension portion is provided with a corner (3a) with a radius less than R0.5.

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