Patent Application
20220336163
This application claims priority pursuant to 35 U.S.C. 119(a) to United Kingdom Patent Application No. 2105356.6, filed Apr. 15, 2021, which application is incorporated herein by reference in its entirety.
The invention relates to an operating mechanism for opening and closing at least one contact, which operating mechanism comprises:
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.
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 re-energized until the cam is rotated to open the contact.
It is an object of the invention to reduce or even remove the above mentioned disadvantages.
This object is achieved according to the invention with an operating mechanism for opening and closing at least one contact, which operating mechanism comprises, a base frame, a bridge body movable relative to the base frame between a closed position and an opened position, wherein the bridge body has a contact surface with a length and a width, which contact surface is configured to extend in length direction over and be in contact with the operating rod of the at least one contact, a rod mechanism of a first and a second link wherein the first ends of the two links are hinging with each other, wherein the second end of first link is hinging with the base frame and the second end of the second link is hinging with the bridging body, a cam arranged on a shaft, wherein the shaft is arranged adjacent to the rod mechanism, wherein the shaft extends parallel to the hinging axes of the rod mechanism and wherein the cam is in operating contact with the hinging axis of the first ends of the two links, a locking lever fixedly arranged with one end to the first link and moves with the first rod between a locked position and an unlocked position, a control shaft having a D-shaft portion with a flat surface portion and a semi cylindrical surface portion, wherein the D-shaft portion can be rotated between a pass position, in which the path of the second end of the locking lever is positioned outside of the circumference of the cross-section of the D-shaft portion, and a lock position, in which the path of the second end of the locking lever intersects with the circumference of the cross-section of the D-shaft portion.
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.
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 re-energized directly after the closing movement is completed.
In a preferred embodiment of the operating mechanism according to the invention a first spring is arranged to the control shaft to urge the control shaft in the lock position.
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.
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.
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.
The cam follower reduces friction and wear between the cam and the rod mechanism.
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, 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.
These and other features of the invention will be elucidated in conjunction with the accompanying drawings.
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.
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.
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.
In
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2105356.6 | Apr 2021 | GB | national |
