ACTUATION MECHANISM

Description

Operating mechanism

[0001] The invention relates to an operating mechanism for opening and closing at least one contact, according to the preamble of claim 1.

[0002] EP 0 302 721 A2A discloses a switch assembly suitable for use as part of an overall electrical circuit breaker. The assembly includes a three-link arrangement consisting of three links interconnected together for movement between a first positional configuration in order to open a circuit and a second positional configuration in order to close the circuit. Means is provided for applying a force to the arrangement in a way which causes the links to move from their first positional configuration to their second positional configuration, and thereafter for maintaining the links in their second positional configuration. An arrangement separate from the force-applying mechanism and including one of the three links is also provided for automatically overriding the application of force to the arrangement in order to cause the links to immediately move back to their first configuration, either during movement to their second configuration or after the links have been moved into their second configuration by the force-applying mechanism, whereby the switch assembly can be tripped back to its open position at any time.

[0003] US 4 409 449 A discloses an operating mechanism for use in a circuit breaker having a stationary contact and a moving contact which is turned on (closed) or off (tripped open) by using the accumulated energy of a stretched spring. The operating mechanism has a frame, a main shaft having a closing cam and an additional cam, a four-joint crank for actuating the moving contact in accordance with the movement of the main cam, a roller clutch mounted around the shaft, a bearing fitting member having an opening mounted around the roller clutch, a gear member having a stud adapted to fit within the opening of the fitting member, and an electric motor and a manually operable handle to drive the spring to accumulate energy.

[0004] CN 205 159 204 U discloses an indoor high-voltage vacuum circuit breaker spring operating mechanism.

[0005] WO 2018 / 115026 A1 discloses a mechanism for opening and closing a circuit breaker having an operating rod for moving the contacts of the circuit breaker between an open position and a closed position. The mechanism comprises a frame; a first rod hingedly arranged with one end to the frame; a second rod hingedly arranged with one end to the other end of the first rod and arranged with the other end slidable to the frame between a contact open position and a contact closed position in a direction substantially perpendicular to the direction of movement of the other end of the first rod.

[0006] In larger (medium voltage) mechanical operated switchgear generally closing of the contact is achieved by the cam operating on the rod mechanism. The opening of the contact typically needs to be quick. This can be done by shaping the cam profile such, that with a minimal rotation of the cam from the closed position, the operating mechanism is release and free to move to the open position without intervention of the cam.

[0007] However in mechanical operated switchgear a spring could also be arranged to the cam, wherein the spring is energized at a certain level and then released to complete the closing operation. The spring is used for achieving the right speed and contact force. If the cam is used to keep the rod mechanism in closed position, the spring cannot be reenergized until the cam is rotated to open the contact.

[0008] It is an object of the invention to reduce or even remove the above mentioned disadvantages.

[0009] This object is achieved according to the invention with an operating mechanism as set forth in claim 1.

[0010] The D-shaft portion in combination with the locking lever provides a lock for the rod mechanism, such that the contact can be kept in closed position, while the cam can be rotated further. When the contact needs to be opened, the D-shaft portion only has to be rotated to release the rod mechanism.

[0011] Now the cam can be rotated further, while the contact is maintained in the closed position, a spring provided to assist in the closing movement, can already be reenergized directly after the closing movement is completed.

[0012] In a preferred embodiment of the operating mechanism according to the invention a first spring is coupled to the control shaft and arranged to urge the control shaft into the lock position.

[0013] This allows for the locking lever to push the D-shaft portion into the pass position, after which the first spring will urge the D-shaft portion back into the lock position, such that the rod mechanism and the contact is locked in the closed position.

[0014] Preferably, a roller is arranged on the locking lever, wherein the roller forms the second end of the locking lever. The roller reduces any friction with the D-shaft portion and improves the urging by the locking lever of the D-shaft portion in the pass position.

[0015] In another embodiment of the operating mechanism according to the invention a cam follower is arranged on the hinging axis of the first ends of the first and second links and wherein the cam follower is configured to be in contact with the cam.

[0016] The cam follower reduces friction and wear between the cam and the rod mechanism.

[0017] In yet another embodiment of the operating mechanism according to the invention, the profile of the cam has a closing profile section for urging the rod mechanism in a stretched position in which the bridge is in the closed position, an opening profile section for letting the rod mechanism fold and an idle profile section, further comprising a closing spring for urging the closing profile section of the cam in contact with the hinging axis of the first ends of the two links.

[0018] These and other features of the invention will be elucidated in conjunction with the accompanying drawings. Figure 1 shows a perspective view of a part of an embodiment of an operating mechanism according to the invention. Figures 2A - 2C show the embodiment of figure 1 in schematical view. Figures 3A and 3B show a detail of the D-shaft portion in the pass position and the lock position respectively.

[0019] Figure 1 shows an operating mechanism 1 for opening and closing a contact. The operating mechanism 1 has a base frame (not shown) and a bridge body 3 with which operating rods of contacts can be operated.

[0020] A rod mechanism of two links 4, 5, which are hinged on one end. A cam follower 6 is provided at this hinge axis. The first link 4 is hinged with the other end 7 to the base frame and the second link 5 is hinged with the other end 8 to the bridge body 3.

[0021] A camshaft 9 with a cam 10 is provided in operating contact with the cam follower 6 to urge the rod mechanism 4, 5 in a stretched position in which the contacts are closed and a collapsed position in which the contacts are opened. A closing spring 11 is connected to the camshaft 9 to assist in the closing movement.

[0022] A locking lever 12 is fixedly arranged to the first link 4 and provided with a roller 13 on the free end of the locking lever 12. A control shaft 14 with a D-shaft portion 15 is provided adjacent the roller 13, to lock the locking lever 12 when the rod mechanism 4, 5 is stretched and the contacts are closed.

[0023] Figure 2A shows the operating mechanism 1 as shown in figure 1 in more schematic view. The bridge body 3 is in a raised position, such that contacts 17 arranged against the contact surface 18 of the bridge body 3 are in an open position. The rod mechanism 4, 5 is collapsed position and the locking lever 12 is rotated away from the D-shaft portion 15, which is urged by a spring 16.

[0024] In figure 2B the cam shaft 9 is rotated such that the cam 10 operates on the cam follower 6 and pushes the rod mechanism 4, 5 in a stretched position, such that the bridge body 3 is moved down and the contacts 17 are closed. This closing action is assisted by the closing spring 11.

[0025] When the rod mechanism 4, 5 is moved to the stretched position, the locking lever 12 with the roller 13 moves along the path 19 and arrives at the D-shaft portion 15, which is positioned in a pass position, where the locking lever 12 with roller 13 can pass the D-shaft portion 15.

[0026] Figure 2C shows the position of the bridge body 3 in closed position, in which the contacts 17 are also closed. The locking lever 12 with roller 13 has passed the D-shaft portion 15, which is rotated by the spring 16 in the lock position, which prevents the rod mechanism 4, 5 to return to the position of figure 2A. This allows for the camshaft 9 to be rotated further in order to re-energize the closing spring 11.

[0027] Figure 3A shows the D-shaft portion 15. The cross-section has a circumference with a straight portion 20 and a semi cylindrical portion 21. In the pass position as shown in figure 3A, the path 19 of the locking lever 12 is positioned outside of the cross-section of the D-shaft portion 15.

[0028] Figure 3A shows the D-shaft portion 15 in the lock position, where the path 19 intersects with the cross-section of the D-shaft portion 15.

Claims

1. Operating mechanism (1) for opening and closing at least one contact (17), which operating mechanism (1) comprises: - a base frame (2); - a bridge body (3) movable relative to the base frame (2) between a closed position in which the at least one contact is closed and an opened position in which the at least one contact is opened, wherein the bridge body (3) has a contact surface (18) with a length and a width, which contact surface (18) is configured to be in contact with an operating rod of the at least one contact (17); - a rod mechanism formed of a first (4) link and a second (5) link, wherein a first end of each of the two links are hinging with each other, wherein a second end (7) of the first link (4) is hinging with the base frame (2) and a second end (8) of the second link (5) is hinging with the bridging body (3); - a cam (10) arranged on a shaft (9), wherein the shaft (9) is arranged adjacent to the rod mechanism (4, 5) such that the cam (10) is in operating contact with a hinging axis of the first ends of the two links (4, 5), wherein the shaft (9) extends parallel to the hinging axes of the rod mechanism (4, 5); characterized by - a locking lever (12) having a first end and a second end (13), the first end fixedly arranged to the second end of the first link (4), wherein the locking lever (12) moves with the first link (4) between a locked position and an unlocked position; - a control shaft (14) having a D-shaft portion (15) with a flat surface portion (20) and a semi cylindrical surface portion (21); wherein the D-shaft portion (15) can be rotated between a pass position, in which a path (19) of the second end (13) of the locking lever (12) is positioned outside of the circumference of the cross-section of the D-shaft portion (15), and a lock position in which the path (19) of the second end of the locking lever (12) intersects with the circumference of the cross-section of the D-shaft portion (15).

2. Operating mechanism (1) according to claim 1, wherein a first spring (16) is coupled to the control shaft (14) and arranged to urge the control shaft (14) into the lock position.

3. Operating mechanism (1) according to claim 1 or 2, wherein a roller (13) is arranged on the locking lever (12) and wherein the roller (13) forms the second end of the locking lever (12).

4. Operating mechanism (1) according to any of the preceding claims, wherein a cam follower (6) is arranged on the hinging axis of the first ends of the first (4) and second (5) links and wherein the cam follower (6) is configured to be in contact with the cam (10).

5. Operating mechanism (1) according to any of the preceding claims, wherein the profile of the cam (10) has a closing profile section for urging the rod mechanism (4, 5) in a stretched position in which the bridge is in the closed position, an opening profile section for letting the rod mechanism (4, 5) fold and an idle profile section, further comprising a closing spring (11) for urging the closing profile section of the cam (10) in contact with the hinging axis of the first ends of the two links (4, 5).