Latching device and an operating mechanism with such a latching device

Abstract

A latching device for an operating mechanism for an electrical switching apparatus. The device has a locking member movable between a first position and a second position. In the first position the locking member is arranged to lock a drive member of the operating mechanism in a locked position, and a force of the drive member being applied to a contact portion of the locking member. In the second position the locking member is arranged to release the drive member from the locked position. At least in the first position the locking member is arranged to bear against the counter roller. A tripping member is movable between a first position locking the locking member and a second position releasing the locking member. The locking member has a first portion and a second portion. The first portion is rotatable connected to a first link around a first pivot axis, which first pivot axis is movable perpendicular to its direction. The second portion is rotatable connected to a second link around a second pivot axis and movable perpendicular to its direction. The second link is rotatable connected to the tripping element around a third pivot axis. Movement of the tripping member from its first position to its second position initiates movement of the contact portion out of force-transmitting relation with the drive member.

Claims

1. A latching device for an operating mechanism for an electrical switching apparatus, the operating mechanism being operatively connectable to the switching apparatus, the latching device comprising: a locking member movable between at least one first position and at least one second position, in the first position the locking member being arranged to lock a drive member of the operating mechanism in a locked position and a force (F) of the drive member being applied to a contact portion of the locking member, and in the second position the locking member is arranged to release the drive member from the locked position, a counter roller defining a first axis (O), at least in the first position the locking member being arranged to bear against the counter roller, a tripping member movable between at least one first trip position and at least one second trip position, in the first trip position the tripping member being arranged to lock the locking member in the first position, and in the second trip position the tripping member is arranged to release the locking member from the locked position, wherein the locking member has a first portion and a second portion, which first portion is rotatable connected to a first link around a first pivot axis (P1), which first pivot axis (P1) is movable perpendicular to its direction, and which second portion is rotatable connected to a second link around a second pivot axis (P2), parallel to the first pivot axis (P1) and movable perpendicular to its direction, which second link is rotatable connected to the tripping member around a third pivot axis (P3) parallel to the first pivot axis (P1), whereby movement of the tripping member from its first trip position to its second trip position initiates movement of the contact portion out of force-transmitting relation with the drive member.

2. The latching device according to claim 1, wherein said links during said movement are arranged to move the contact portion in a direction having a first component in the longitudinal direction of the locking member and a second component perpendicular thereto.

3. The latching device according to claim 2, wherein the length of the locking member is in the range of 1.3-5 times the length of each of the first and second links, preferably in the range of 1.8-2.5.

4. The latching device according to claim 2, wherein the length of the first link is within the range of 0.7-1.5 times the length of the second link, preferably within the range of 0.9-1.1 times.

5. The latching device according to claim 2, wherein the first link is rotatable around a fourth pivot axis parallel to the first pivot axis (P1).

6. The latching device according to claim 2, wherein the third pivot axis (P3) is movable perpendicular to its axis.

7. The latching device according to claim 1, wherein the first link is rotatable around a fourth pivot axis (P4) parallel to the first pivot axis (P1).

8. The latching device according to claim 7, wherein the position of the fourth pivot axis (P4) is fixed.

9. The latching device according to claim 1, wherein the third pivot axis (P3) is movable perpendicular to its axis.

10. The latching device according to claim 1, wherein the tripping member is rotatable around a fifth pivot axis (P5) parallel to the first pivot axis (P1).

11. The latching device according to claim 10, wherein the position of the fifth pivot axis (P5) is fixed.

12. The latching device according to claim 1, and further including a trigging member actuated by an electro-magnet, which trigging member is arranged to act on the tripping member to move the tripping member from its first trip position to its second trip position by applying a tripping force on the tripping member.

13. The latching device according to claim 12, wherein the tripping member includes a first lever arm to which the second link is connected and a second lever arm, on which the trigging member is arranged to act.

14. The latching device according to claim 1, wherein the length of the locking member is in the range of 1.3-5 times the length of each of the first and second links, preferably in the range of 1.8-2.5.

15. The latching device according to claim 1, wherein the length of the first link is within the range of 0.7-1.5 times the length of the second link, preferably within the range of 0.9-1.1 times.

16. The latching device according to claim 15, wherein the spring means acts on the connection between the second link and the tripping member or adjacent thereto.

17. The latching device according to claim 1, and further including spring means counter-acting the triggering force and being arranged to return the locking member from its second position to its first position once the actuation has been completed.

18. The latching device according to claim 17, wherein the spring means acts on the connection between the second link and the tripping member or adjacent thereto.

19. The latching device according to claim 1, wherein the locking member is arranged to bear against the counter roller during at least a major part of the movement from its first position to its second position.

20. An operating mechanism for an electrical switching apparatus, the operating mechanism being operatively connectable to the switching apparatus, and the operating mechanism comprises a latching device and a drive member movable in relation to the latching device between at least one locked position and at least one released position, wherein the latching device includes the features mentioned in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic illustration of an example of a latching device according to the invention in a first, locked position.

(2) FIG. 2 is a schematic illustration of the latching device of FIG. 1 in a second, released position.

DETAILED DESCRIPTION

(3) The latching device is in FIG. 1 illustrated in the position when it keeps the operating mechanism 100 of an electrical switching apparatus, e.g., a breaker in a locked position. In that position the breaker is ready for an opening of the breaker should that be required. The operating mechanism may be of conventional kind and need no explanation to the person skilled in the art. Thus, the operating mechanism is mainly indicated as a box 100 and only the drive member 101 thereof, which cooperates with the invented latching device, is illustrated.

(4) The operating mechanism thus conventionally may have a rotatable drive unit drivingly connected to a rotary drive shaft, which drive shaft is arranged to transmit an actuating movement to the switching apparatus, e.g., to a mobile contact part of the switching apparatus via a mechanical structure known to the skilled person. The mobile contact is movable to and from another contact part to close and open a current path. The operating mechanism may in a conventional manner be provided with biasing means, e.g., a loaded torsion spring, which forces the drive unit thereof and therewith the drive member in a first direction around the drive shaft. In the figure this rotational direction is clockwise.

(5) Upon call for a closing operation, the latching device releases the locked drive unit so that it rotates clockwise, whereby the device reaches the position illustrated in FIG. 2. Shortly thereafter the latching device resets the drive unit to its original position in FIG. 1 such that it is ready for another opening operation. This is the general function of a latching device in this context. In the following the particulars of a latching device according to the invention will be described more in detail.

(6) Referring to FIG. 1, the latching device includes a locking member 1, which at its upper end abuts the drive member 101 of the operating mechanism. The drive member 101 is provided with a contact unit 102 pivotally connected thereto. The contact unit 102 is biased by a tension spring 103 in the clockwise direction. The lower end of the locking member 1 abuts a counter roller 2, rotatable around a roller axis O. The drive member 101 exerts a contact force on the locking member 1 due to the rotational biasing thereof mentioned above. The counter roller 2 supports the locking member 1 and thereby takes almost the complete force from the drive member.

(7) The contact force between the drive member 101 and the locking member 1 has a direction that mainly, but not completely aligns with the longitudinal extension of the locking member 1. The direction of the contact force F is illustrated in the figure, however somewhat exaggerated for illustrative purpose. Preferably the angle between the contact force F and the longitudinal direction of the locking member 1, i.e., the direction from the contact point between the locking member 1 and the contact part 102 of the drive member 101 to the contact point between the locking member 1 and the counter roller, should be about 1. This means that about 99% of the force is taken up by the counter roller 2, whereas about 1% is taken up by the link 5.

(8) At a first portion 12 of the locking member 1, the locking member is pivotally connected to a first end of a first link 4 around a first pivot axis P1. In the illustrated example this connection is located at the upper end of the locking member close to the contact point. The first pivot axis P1 extends perpendicular to the plane of the paper and thus is in parallel to the rotational axis (not shown) of the operating mechanism 100. The first axis P1 is movable perpendicular to the direction thereof. The second end of the first link 4 is pivotable around a fourth pivot axis P4, which is stationary and in parallel to the first pivot axis P1.

(9) A second portion 13 of the first member 1 is pivotally connected to a first end of a second link 5 around a second pivot axis P2, which is in parallel to the first pivot axis P1 and is movable perpendicular to its direction. The second pivot axis P2 is in this example located at the lower end of the locking member 1 close to its contact point with the counter roller 2.

(10) The second link 5 is pivotally connected to a tripping member 3 around a third pivot axis P3. The third pivot axis P3 is in parallel to the first pivot axis P1 and is movable perpendicular to its direction. The tripping member 3 in this example is configured as a lever rotatable around a fifth pivot axis P5 which is stationary and in parallel to the first pivot axis P1. It has two lever arms 31, 32 diametrically arranged in relation to each other. The second link 5 is connected to the end of the first lever arm 31.

(11) A tension spring 7 is connected to the pivotal joint between the second link 5 and the first lever arm 31.

(12) Adjacent the second lever arm 32 an electromagnet 6 is located, which is provided with a plunger 61 arranged to be able to act on the second lever arm 32.

(13) Upon a signal indicating that the breaker need to be opened, the electromagnet 6 is activated which results in a releasing of the drive unit 100 to accomplish opening and the device will reach the position illustrated in FIG. 2.

(14) This occurs in the following way: Activation of the electromagnet 6 affects the plunger 61 to pivot clockwise. Thereby the plunger 61 hits the second level arm 32 such that the tripping member 3 will rotate counter-clockwise. The pivot joint between the second link 5 and the first level arm 31, with the third pivot axis P3 will thus move along a circular line in the counter-clockwise direction. The second picot axis P2, at the joint between locking member 1 and the second link 5 thereby will move clockwise along a circular path adjacent the periphery of the counter roller 2. This is because of the downwardly and increasingly rightwardly directed pulling force from the first lever arm 31 on the second link 5. The first pivot axis P1 where the locking member 1 is connected to the first link 4 thereby also will move downward and leftward along a circular path defined by the first link 4 as it rotates counter-clockwise around the fourth pivot axis P4.

(15) This movement of the first pivot axis P1 moves the contact point 11 of the locking member 1 out of contact with the contact unit 102 of the drive member 101 both in the downward and in the rightward direction. The rightwardly directed component of the movement gives free way for the drive member 101 to move downwards, as illustrated in FIG. 2, and thereby open the breaker by rotating the operating mechanism. The drive member 101 thus does not have to push the locking member 1 as it moves, which otherwise would slow down its speed. Neither will it be affected by any friction from the locking member 1 since it is out of its way. An opening operation with a device according to the claims can be achieved as fast as in 7 milliseconds.

(16) The force necessary for the plunger 61 to act on the level 3 corresponds substantially to the horizontal component of the contact force F. The horizontal component is about 1% of the contact force F, i.e., the locking force. The ratio of the required triggering force to the locking force is thus about 1:100.

(17) During the opening movement the tension spring 7 will be tensioned by the movement of the joint around the third pivot axis P3. When opening is completed the tension spring 7 will pull the device back to its starting position as illustrated in FIG. 1. During resetting of the device, the contact unit 102 of the drive member 101 will be somewhat retracted in the clock-wise direction due to the spring 103. This facilitates for the drive member 101 to pass the locking member 1 when counter-clockwise returning to the FIG. 1 position.