EP2430322B1

EP2430322B1 - Lock device for restricting rotational movement

Info

Publication number: EP2430322B1
Application number: EP09844511.7A
Authority: EP
Inventors: Fei Cen; Xiaobo Huang
Original assignee: ABB Technology AG
Current assignee: ABB Technology AG
Priority date: 2009-05-15
Filing date: 2009-05-15
Publication date: 2016-01-27
Anticipated expiration: 2029-05-15
Also published as: CN102369361B; EP2430322A1; WO2010130099A1; EP2430322A4; CN102369361A

Description

FIELD OF THE INVENTION

This invention relates to the field of power products and mechanics, and more particularly to a lock mechanism for restricting rotational movement.

BACKGROUND OF THE INVENTION

Busbar voltage transformer (abbreviate VT or PT) are used to measure the voltage on Busbar. Sometimes, the PT needs maintenance while the Busbar is still in service. Then the PT needs to be isolated from the main circuit, which is implemented by a PT disconnector. The PT disconnector is located in a gas tank of gas insulated switchgear (GIS). The PT disconnector is connected with insulated material in the gas tank and with the handle outside the gas tank. A rotatable shaft is used to drive the disconnector switching from connected state to disconnected state. The shaft is accessible to and can be operated by anyone outside the gas tank, which is a risk for the GIS and the operators. Thus, safety assurance is needed to prevent unauthorized rotation of the shaft.
Padlock was adopted to prevent unauthorized operation of the PT disconnector by restricting the rotational movement of the shaft.
A traditional lock mechanism is shown in Fig. 1A to 1C. Fig. 1A shows the structure of the lock device. It mainly comprises four parts: a plate 92, a fixing plate 93, a padlock 94 and a handle 95. The handle 95 and the plate 92 are fixed on a rotatable shaft 91 which is used to operate the disconnector. The fixing plate 93 is fixed to the side-plate of the switchgear. There is a hole 921 on the plate 92 and a second hole 931 on the fixing plate 93.
When the plate 92 and fixing plate 93 are not locked by the padlock 94, see Fig. 1B, the handle 95 can be operated and it drives the shaft 91 to rotate. Thus, the PT disconnector can be operated.
Otherwise, see Fig. 1C, when the padlock 94 is plugged into the holes 921, 931, the plate 92 and fixing plate 93 are locked by the padlock 94. The rotatable shaft 91, the handle 95 and the plate 92 are fastened together. Thus the shaft 91 is prohibited from rotating, which prevents unauthorized operation of the PT disconnector.
Although the lock device described above can prevent unauthorized operation of the PT disconnector, it has some disadvantages:

1) The traditional lock device can not meet IP4X requirement. It is a safety risk for the switchgear that the hole on the fixing plate is located in the enclosure of the switchgear.
Degrees of protection according to IEC 60529 and IEC 62262 are specified for all enclosures of high-voltage switchgear and controlgear containing parts of the main circuit allowing penetration from outside as well as for enclosures for appropriate low-voltage control and/or auxiliary circuits and mechanical operating equipment of all high-voltage switchgear, controlgear and switching devices. The degree of protection of persons against access to hazardous parts and protection of the equipment against ingress of solid foreign objects is indicated by means of a designation specified by the IP coding.
According to IP4X, the protection should prevent ingress of solid foreign objects of 1.0 mm diameter and greater, and access to hazardous parts with a test-wire 1.0 mm in diameter and 100 mm long.
2) In order to ensure the padlock being plugged in the holes on the plate and the fixing plate, the diameters of the holes must be designed to be a little longer than the diameter of the U-shaped bar of the padlock. The clearance between the holes and the U-shaped bar of the padlock makes it possible that the shaft be rotated at a slight degree even the plate and the fixing plate are locked, which may result in misoperation of the disconnector.

FR 2 299 710 A1 discloses a device with a locking mechanism having a bush adapted to rotate about an axial direction and to move along said axial direction. A rotation of the bush and a movement of the bush in the axial direction can be restricted.
JP 2000 243193 A discloses a lock mechanism of an operating device for a switch. A shutter having a lock-pin insertion hole formed therein and agreeing with the axis of a manually operated shaft is disposed on the front side of the manually operated shaft so that it can make a turning motion centering around a shaft, and a lock pin is provided having a metallic stopper part fastened to its base end part and limiting the rotation of the manually operated shaft by abutting on the shutter when the lock pin is mounted in the manually operated shaft.

SUMMARY OF THE INVENTION

To overcome above shortcomings, the main purpose of the present invention is to increase safety and reliability when restricting rotational movement. This object is achieved by a lock device and a gas insulated switchgear with a disconnector described as following.
According to one aspect of the invention, a lock device for restricting unauthorized rotating movement is provided. The lock device comprises a bush or cylinder which is adapted and arranged to rotate about an axial direction and to move along said axial direction between two axial positions. The bush comprises a first protrusion adapted to interact with a first counterpart which is fixed in rotational direction in order to restrict, in a locked position of the first protrusion, the rotation of said bush. The lock device further comprises a second counterpart adapted to prevent the axial movement of said bush out of said locked position of the first protrusion.
According to another preferred embodiment of the present invention, said second counterpart is a handle which is coupled to the bush in said axial direction. The handle comprises a first surface. The first surface is adapted to abut against, in a locked position of said handle, a third counterpart fixed in axial direction. The third counterpart inhibits an axial displacement of the handle, and prevents the bush from moving in axial direction out of the locked position of the first protrusion.
According to the preferred embodiment, the handle further comprises a second surface, wherein the second surface is adapted to touch, in an unlocked position of said handle, said third counterpart. In this position, the handle and bush will have been moved in said axial direction, releasing the protrusion out of the locked position of the first protrusion into a release position, and permitting the bush to rotate about said axial direction.
According to the preferred embodiment, the bush encloses a hole in the transverse direction fitted to accommodate the handle. The handle has a circular cross-section, and said first surface and second surface correspond to the two parts of the handle of different diameters. In particular, the first surface is the surface of the long diameter part and second surface is the surface of the short diameter part.
According to the preferred embodiment, the handle further comprises an opening fitted to accommodate a fourth counterpart. The fourth counterpart is plugged in the opening to prevent the handle from moving between the first position and the second position. For example, the fourth counterpart is a padlock or a:bolt.
According to a preferred embodiment of the present invention, the bush encloses a cavity with a non-circular cross-section fitted to accommodate a shaft. The cavity is adapted to transfer rotational, but not axial movement between the bush and the shaft. For example, the cross-section of said cavity is quadrate or rhombic. A shaft is fitted to the cavity to be able to rotate about said axial direction in response to the rotation of the bush.
According to a preferred embodiment of the present invention, the third counterpart is a second protrusion that is part of the shaft or a separated component which is fixed on the shaft. For example, the second protrusion is a bolt which is fixed on the shaft.
According to a preferred embodiment of the present invention, the lock device further comprises a plate or other support means fixed in the axial direction, with a circular hole adapted to accommodate the bush. The first counterpart is arranged or provided on the plate. The first protrusion is a bulge on the exterior of the bush and the first counterpart is a notch adapted to the protrusion. The notch can be quadrate or rhombic.
According to a preferred embodiment of the present invention, the lock device further comprises a spring, arranged in axial direction to support or reinforce the locked position of the bush. The force of the spring has to be counteracted by an operator unlocking the bush/protrusion, and makes a flange of the bush cling to plate tightly in said locked position of first protrusion.
According to the other aspect of the invention, a gas insulated switchgear with a disconnector is provided. Said gas insulated switchgear comprises a lock device as described above which is arranged to prevent unauthorized operation of said disconnector.
According to the preferred embodiment, the gas insulated switchgear further comprises a state-plate rotationally coupled to the bush to indicate different states of said disconnector.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the invention will be explained in more details in the following description with reference to preferred exemplary embodiments which are illustrated in the drawings, in which:

Fig. 1 is a schematic view of the conventional lock device; in which Fig. 1A shows the structure of the conventional lock device, Fig. 1B shows the unlocked state of the conventional lock device; Fig. 1C shows the locked state of the conventional lock device;
Fig. 2A shows the structure of the present invention according to one preferred embodiment; Fig. 2B shows another example of structure which is not part of the present invention;
Fig. 3A is a schematic view of locked state according to the first preferred embodiment; Fig. 3B is a section view of the lock device in locked state according to the first preferred embodiment; Fig. 3C is a schematic view of unlocked state according to the first preferred embodiment; Fig. 3D is a section view of the lock device in unlocked state according to the first preferred embodiment; Fig. 3E is a schematic view of locked state of the other example of structure which is not part of the present invention; Fig. 3F is a schematic view of unlocked state of the other example of structure which is not part of the present invention;
Fig. 4 is a schematic view of the lock device being fixed to the plate of the gas insulated switchgear;
Fig. 5 is a local enlargement view of airtight connection between shaft and gas tank of the switchgear;
Fig. 6 shows the structure of other components for the lock device to prevent unauthorized operation of the disconnector of switchgear according to one preferred embodiment;
Fig. 7 is a schematic view of the lock device corresponding to the two states of the switch, in which Fig. 7A shows the switch in connecting state; Fig. 7B shows the switch in earthing state;
Fig. 8 shows some variations and modifications to the preferred embodiments, in which Fig. 8A shows a variation of the notches, Fig. 8B shows a triangular cross section shaft; Fig. 8C shows the interaction of the notch with the bulge and the interaction of the cavity of the bush with the triangular-cross-section shaft.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to the above-mentioned figures, preferred embodiments of the present invention are provided. As shown in Fig. 2A, the lock device for restricting rotational movement according to the first preferred embodiment comprises a bush 3 adapted to rotate about an axial direction 100 and to move along the axial direction 100. The bush 3 comprises a bulge 32 adapted to interact with notches 12 in order to restrict, in a locked position of the bulge 32, the rotation of the bush 3. The lock device further comprises a handle 4 adapted to prevent the bush 3 from moving in axial direction 100 out of the locked position of the bulge 32.
The handle 4 has a circular cross-section, and two parts with different diameters. As shown in Fig. 3A and Fig. 3B, the first surface 43, which is the surface of the long diameter part, is adapted to abut against, in a locked position 400 of the handle 4, a protrusion 21 fixed in axial direction 100, in order to prevent the bush 3 from moving in axial direction 100 out of the locked position of the bulge 32. As shown in Fig. 3C and Fig. 3D, the second surface 42, which is the surface of the short diameter part, is adapted to touch a protrusion 21 in an unlocked position 401 of the handle 4. In this unlocked position 401, the handle 4 and bush 3 will have been moved in the axial direction 100, releasing the bulge 32 out of the locked position into a release position, and permitting the bush 3 to rotate about the axial direction 100.
According to the first preferred embodiment, the bush 3 comprises an opening 33 in a transverse direction 101 fitted to accommodate the handle 4 and to couple the handle 4 to the bush 3 in the axial direction 100. The handle 4 further comprises a second opening 41 fitted to accommodate a padlock or a bolt 5. When the padlock 5 is plugged in the second opening 41, the handle 4 is fastened in the locked position 400 and the protrusion 21 abuts against the first surface 43 of the handle 4, which prevents the bush 3 and the handle 4 to move in the axial direction 100. Thus the bush is locked by the bugle 32 in the notches 12 and is prevented from rotating. When the padlock 5 is removed from the second opening 41, the handle 4 can move in the transverse direction 101. Then the protrusion 21 will not abut against any surface of the handle 4, as the second surface 42 is the surface of the short diameter part of the handle 4. Thus, the bush 3 can be moved in the axial direction 100 until the protrusion 21 touch the second surface 42 in unlocked position 401 of the handle. In this position, the bulge 32 will have moved out of the notches 12. Thus the bush 3 will be released from the locked position of the bulge 32 into a release position, and can rotate about the axial direction 100.
According to the first preferred embodiment, the protrusion 21 is part of a shaft 2 fixed in the axial direction 100, or a bolt fixed on the shaft 2. The length of the protrusion 21 is fitted to abut against the first surface 43 of the handle 4 to lock the bulge 32 of the bush 3 in the notches 12, and to release the bulge 32 of the bush 3 from the notches 12 when it touches the second surface 42.
Fig. 2B shows another example of structure which is not part of the present invention. The bush 3 comprises an opening 33' adapted to couple with an opening 23' on a shaft 2 which is fixed in the axial direction 100 to prevent the bush 3 from moving in the axial direction 100 out of the locked position of the bulge 32.
According to the other example of structure which is not part of the present invention, the lock device further comprises a padlock or a bolt 4'. As shown in Fig 3E, when the padlock 4' is plugged in the opening 33' of the bush 3 and coupled to the opening 23' on the fixed shaft 2, the bush 3 is fastened in a locked position and can not move in the axial direction 100. Thus the bush 3 is locked by the bugle 32 in the notches 12 and is prevented from rotating. Fig. 3F is a schematic view of unlocked state according to the other example of structure which is not part of the present invention When the padlock 4' is removed, the opening 33' will be released from coupling with the opening 23' of the fixed shaft 2. Thus, the bush 3 can be moved towards the notches 12 in the axial direction 100 and the bulge 32 will be moved out of the notches 12. Thus the bush 3 will be released from the locked position of the bulge 32 into a release position, and can rotate about the axial direction 100.
According to this other example of structure which is not part of the present invention, in order to rotate the bush 3 in unlocked state efficiently, the lock device further comprises a handle 40' fixed on the bush 3.
According to the preferred embodiments of present invention, the cross section of the bulge 32 and the notches 12 are quadrate or rhombic and adapted to interact with each other.
According to the preferred embodiments of present invention, the bush 3 encloses a cavity 31 fitted to accommodate a shaft 2, as shown in Fig. 3A, 3C, 3E and 3F, wherein the cross section of the cavity 31 is not circular. And the lock device further comprises a shaft 2 adapted to transfer rotational, but not axial movement between the bush 3 and the shaft 2. For example, the cross section of the shaft 2 and the cavity 31 of the shaft 2 are quadrate or rhombic.
According to the preferred embodiments of present invention, the lock device further comprises a plate 1 with a circular hole 11 adapted to accommodate the bush 3; as shown in Fig. 3A to 3F, wherein two notches 12 are arranged on the plate 1. The two notches 12, by interacting with the bulge 32, lock and prevent the bush 3 from rotating in correspondence with the two states of the switch: connecting state and disconnecting earthing state.
According to the preferred embodiments of present invention, the lock device further comprises a spring 61, arranged in the axial direction 100 to exert a pre-tight force for making the bush 3 cling to the plate 1. The force of the spring 61 has to be counteracted by an operator when unlocking the bush/protrusion. And when the bulge 32 of the bush 3 can be moved into the notches 12, the force of the spring 61 drives the bush 3 to move backwards from the notches 12 in the axial direction 100 into the locked position of the bulge 32 and makes a flange of the bush 3 cling to the plate 1 tightly.
According to the other aspect of the invention, the lock device is used in a gas insulated switchgear that comprises a disconnector. The gas insulated switchgear comprises a lock device as described above which is arranged to prevent unauthorized operation of the disconnector. Fig. 4 is a schematic view of the lock device fixed to the plate of the gas insulated switchgear.
To prevent unauthorized operation of the disconnector, the lock device needs to be seal connected with the GIS. Fig. 5 is a local enlargement view of airtight connection between shaft 2 and gas tank of the switchgear. As shown in Fig. 6, the shaft 2 further comprises a section of piston 63 at the GIS side, which fits with the inner hole of bearing or cylinder 64. The bearing is fixed to the gas tank. There are two annular grooves 65 at the surface of the piston 63, and wherein two elastic "O" rings are adopted to achieve airtight connection between the shaft 2 and bearing.
According to a preferred embodiment, as shown in Fig. 6, the gas insulated switchgear further comprises a state-plate 62 rotationally coupled to the bush 3 to indicate different states of the disconnector. To rotationally couple to the bush 3, the state-plate 62 comprises a notch 622 same with the notch 12 on the plate 1. The state-plate 62 further comprises two state-markers 627 adapted to an opening 17 and the two notches 12 on the plate 1. When the bush 3 is locked by bulge 32 in one of the notches 12, one of the state-markers 627 is correspondingly shown through the opening 17 on the plate 1 and indicates the state of the switch. Fig. 7 is a schematic view of the lock device corresponding to the two states of the switch, in which Fig. 7A shows the switch in connecting state; Fig. 7B shows the switch in earthing state. The state-marker 627 shows "I" in connecting state, while shows "O" in disconnecting earthing state.

Advantage of the lock device according to this invention:

The lock device according to the present invention prevents the rotation of the shaft inside the switchgear by components outside the switchgear without opening inside the switchgear. This makes the lock device of the present invention safer and meets IP 4X requirement.
Through the precise joint of the protrusion and the handle, the precise engagement of the notches and the bulge, the shaft can not be rotated in the slightest degree. Thus the present invention provides a perfect lock mechanism.
Though the present invention has been described on the basis of some preferred embodiments, those skilled in the art should appreciate that those embodiments should by no means limit the scope of the present invention. There are many variations and modifications to the embodiments. For example, Fig. 8A shows a variation of the notches 12', Fig. 8B shows a triangular cross section shaft 2'; Fig. 8C shows the interaction of the notch 12'with the bulge 32' and the interaction of the cavity 31' of the bush 3 with the triangular cross section shaft 2'. As shown in above figures, the modifications to the notches 12' can also lock the bush 3 in a locked position of the bulge 32', and the triangular cross section cavity 31' of the bush 3 can also transfer rotational movement between the bush 3 and the shaft 2'.

Claims

A lock device for restricting rotational movement, comprising a bush (3) adapted to rotate about an axial direction (100) and to move along said axial direction (100); the bush (3) comprising a first protrusion (32) adapted to interact with a first counterpart (12) in order to restrict, in a locked position of the first protrusion (32), the rotation of said bush (3);
said lock device further comprising a second counterpart (4, 4') adapted to prevent the bush (3) from moving in axial direction (100) out of the locked position of the first protrusion (32),
characterized in that
said second counterpart is a handle (4) adapted to be coupled to said bush (3) in said axial direction (100); said handle (4) comprising a first surface (43) adapted to abut against, in a locked position (400) of said handle (4), a third counterpart (21) fixed in axial direction (100), in order to prevent the bush (3) from moving in axial direction (100) out of the locked position of the first protrusion (32).
The lock device according to claim 1, characterized in that said handle (4) further comprises a second surface (42), wherein the second surface (42) is adapted to touch, in an unlocked position (401) of said handle (4), said third counterpart (21) to permit the bush (3), in a release position of the first protrusion (32), to rotate about said axial direction (100).
The lock device according to claim 1, characterized in that the bush (3) comprises a first opening (33) in a transverse direction (101) fitted to accommodate said handle (4) and to couple said handle to the bush.
The lock device according to claim 1, characterized in that said handle (4) further comprises a second opening (41) fitted to accommodate a fourth counterpart (5); wherein said fourth counterpart (5) is plugged in said second opening (41) to prevent the handle (4) from moving between said locked position (400) and said unlocked position (401).
The lock device according to claim 2, characterized in that said handle (4) has a circular cross-section, and said first surface (43) and second surface (42) correspond to two parts of handle (4) of different diameters.
The lock device according to claim 1, characterized in that said bush (3) encloses a cavity (31) fitted to accommodate a shaft (2), wherein a cross-section of the cavity (31) is not circular.
The lock device according to claim 6, characterized in that said third counterpart (21) is a second protrusion that is part of a shaft (2) fixed in axial direction, or said third counterpart (21) is a second protrusion that is a separated component being fixed on said shaft (2).
The lock device according to claim 1, characterized in that it further comprises a plate (1) with a circular hole (11) adapted to accommodate said bush (3); wherein said first counterpart (12) is arranged on the plate (1).
The lock device according to claim 8, characterized in that said first counterpart (12) is a notch, and said notch (12) is at one point of the circumference of said first circular hole (11).
The lock device according to claim 1, characterized in that it further comprises a spring (61) arranged in the axial direction (100) to support said locked position of first protrusion (32).
A gas insulated switchgear with a disconnector characterized in that it comprises a lock device according to any one of the preceding claims in order to prevent unauthorized operation of said disconnector.
The gas insulated switchgear according to claim 11, characterized in that it further comprises a state-plate (62) rotationally coupled to the bush (3) in order to indicate different states of said disconnector.