SWITCHING DEVICE AND LINKAGE MECHANISM THEREOF

Abstract

 The present invention relates to a switching device and a linkage mechanism thereof. The linkage mechanism comprises a drive shaft which is capable of rotating around a center, two moving contacts which are arranged in parallel and are centrosymmetric with respect to the center, the moving contacts being capable of rotating around respective fixed pivot points, and two connecting rods which are centrosymmetric with respect to the center, the two ends of each of the connecting rods being pivotably connected to one end of the drive rod and one of the moving contacts, respectively.

Description

Technical field

[0001] The present invention relates to a linkage mechanism, in particular to a linkage mechanism used in a switching device, and a switching device using the linkage mechanism.

Background art

[0002] In a switching device (e.g. an isolating switch), switching between an open position and a closed position is achieved by operating a drive shaft; a transmission shaft is set in motion to bring into contact or separate a moving contact point and fixed contact point, thereby controlling the switching device to close or open, in order to control the switching of a power supply line on or off.

[0003] When a switching device opens, an arc will form between the fixed contact and moving contact. A double break-point contact system can strike an arc quickly, so that the moving contact and fixed contact are not welded together, thereby increasing the switching device's ability to switch on or off, as well as its electrical lifespan.

Content of the invention

[0004] An object of the present invention is to provide a linkage mechanism capable of further increasing the synchrony of two moving contacts.

[0005] Another object of the present invention is to provide a switching device with higher moving contact synchrony.

[0006] The present invention provides a linkage mechanism of a switching device, comprising
a drive shaft which is capable of rotating around its center and has a pair of drive rods,
two moving contacts which are arranged in parallel and are centrosymmetric with respect to the center, the moving contacts being capable of rotating around respective fixed pivot points,
and two connecting rods which are centrosymmetric with respect to the center, the two ends of each of the connecting rods being pivotably connected to one end of the drive rod and one of the moving contacts, respectively.

[0007] Since the moving contacts and connecting rods etc. on the two sides of the drive rods are in a centrosymmetric state, it is possible to ensure that the positions of the two moving contacts are the same; in other words, they can come into contact with the static contacts at the same time, and break contact with the static contacts at the same time. This means that arcs can be struck more quickly, and welding between a moving contact and a static contact can be better avoided. Furthermore, since the linkage mechanism employs four connecting rods, it generates less friction than if a crank and slider were to be employed. Therefore the movement speed of the moving contacts will also be further increased, and the faster speed will be of greater help in further increasing the arc striking efficiency.

[0008] The present invention further provides a switching device, comprising
a housing,
two static contacts fixed to the housing,
and a linkage mechanism as described above, wherein the moving contact can come into contact with or be separated from one of the static contacts.

[0009] The use of such a linkage mechanism will further increase the switching device's ability to switch on or off, as well as its electrical lifespan.

[0010] In one embodiment of the present invention, the switching device may further comprise a limiting mechanism disposed on the housing, the limiting mechanism being capable of limiting the rotation angle of the drive rods. This allows the movement of the drive rods to be limited to within a preset range.

[0011] In one embodiment, the limiting mechanism is a pair of protrusions located at two ends of the center. When the drive rods rotate to a specific angle, they will be obstructed by the protrusions, so that the possibility of further rotation is limited.

[0012] In one embodiment, when the switching device is in a disconnected state, the moving contacts are not in contact with the static contacts, and the drive rods are in contact with the limiting mechanism.

[0013] In one embodiment, the switching device is an isolating switch.

Description of the accompanying drawings

[0014] The above characteristics, technical features and advantages of the present invention as well as embodiments thereof are explained further below in a clear and easy to understand way, by explaining preferred embodiments with reference to the accompanying drawings, wherein:

Fig. 1 is an exploded schematic view of a switching device having an embodiment of a linkage mechanism;

Fig. 2 is a schematic diagram of the switching device in Fig. 1;

Fig. 3 is a schematic simplified drawing of an embodiment of a linkage mechanism in an OFF state;

Fig. 4 is a schematic simplified drawing of an embodiment of a linkage mechanism when moving from an OFF state to an ON state;

Fig. 5 is a schematic simplified drawing of an embodiment of a linkage mechanism in an ON state.

[0015] Key to labels:

10 drive shaft

10a, 10b drive rods

20a, 20b connecting rods

30a, 30b moving contacts

50a, 50b static contacts

60a, 60b fixed frames

90 housing

91, 92 limiting mechanisms

P center

Particular embodiments

[0016] To furnish a clearer understanding of the technical features, objects and effects of the present invention, particular embodiments thereof are now explained with reference to the accompanying drawings, in which identical labels indicate identical parts.

[0017] In an embodiment of the present invention, a linkage mechanism of a switching device is provided, as shown in Figs. 1, 2 and 3, comprising a drive shaft 10 capable of rotating around a center P. A pair of drive rods 10a and 10b is provided on the drive shaft 10, the two drive rods being centrosymmetric relative to the center P. Moving contacts 30a and 30b, which are arranged in parallel and are centrosymmetric with respect to the center point P, are also provided. These two moving contacts are fixed at one end to fixed frames 60a and 60b, respectively, and are therefore able to rotate around respective fixed pivot points. Furthermore, also included are connecting rods 20a and 20b, which are centrosymmetric with respect to the center P. These two connecting rods are each connected to one drive rod and one moving contact; in other words, the two ends of each of the connecting rods are pivotably connected to one end of the drive rod and one of the moving contacts, respectively.

[0018] Specifically, each moving contact may comprise two parts. Taking moving contact 30a as an example, moving contact plates 31a and 32a may sandwich fixed frame 60a and be fixed to a housing 90 by means of a pin, and sandwich connecting rod 20a by means of another pin. This gives connecting rod 20a a certain degree of freedom with respect to moving contact 30a.

[0019] Since one end of the moving contact is fixed, the connecting rod is connected to the remaining part of the moving contact; thus, one moving contact and one connecting rod form a three-connecting-rod structure. With the other end of the connecting rod being connected to a drive rod, furthermore, one moving contact, one connecting rod and one drive rod form a four-connecting-rod structure.

[0020] In this way, two four-connecting-rod structures are formed with the center point P as the center of symmetry (10a, 20a and the two sides of 30a; and 10b, 20b and the two sides of 30b), with the four-connecting-rod structures on the two sides being centrosymmetric relative to point P.

[0021] The arrangement of the fixed pivot points of the moving contacts is also centrosymmetric relative to the center. For example, one is located at the top left, while the other is located at the bottom right; of course, it is also possible to have one disposed at the bottom left, and the other disposed at the top right.

[0022] As is known, if a figure can coincide with another figure when rotated 180° about a given point, then these two figures are symmetric with respect to that point, which is called the center of symmetry. In this embodiment, if the center P is taken as the boundary, the mechanisms on the two sides can in fact each form a four-connecting-rod structure, and the four-connecting-rod mechanisms on the two sides are symmetric relative to the center.

[0023] The use of a connecting rod mechanism makes the structure of the whole linkage mechanism simple, avoiding the problem of a complex mechanism when a crank-slider structure is used for example. Thus the whole structure is more stable and reliable, and easier to manufacture.

[0024] Furthermore, the movement speed of the moving contact is related to the arc extinguishing efficiency. A slider is subject to friction when moving, leading to a reduction in the movement speed of the moving contact and other phenomena, but when the linkage mechanism provided in the embodiments of the present invention is used, this problem will not arise, so that the movement speed of the moving contact is increased, further increasing the arc extinguishing efficiency.

[0025] The centrosymmetric arrangement enables the two moving contacts to move in synchrony; in other words, the two moving contacts can come into contact with static contacts at the same time, and break contact with the static contacts at the same time, without a situation arising whereby the moving contact on one side has already come into contact with a static contact but the moving contact on the other side has still not come into contact with a static contact. Thus the phenomenon of welding between a moving contact and a static contact is also avoided.

[0026] Specifically, as Fig. 3 shows, when the switching device is in an OFF position, the two moving contacts are both remote from the static contacts in a manner which is centrosymmetric relative to point P. When the switching device needs to switch to an ON position, as shown in Fig. 4, the drive shaft rotates anticlockwise around its center point P, thereby turning the drive rods 10a and 10b thereof, and correspondingly pushing the moving contacts 30a and 30b to move towards the static contacts 50a and 50b, until the moving contacts 30a and 30b simultaneously come into contact with the static contacts to which they respectively correspond as shown in Fig. 5.

[0027] The present invention also provides a switching device, for example an isolating switch, as shown in Figs. 1 and 2, comprising a housing 90, two static contacts 50a and 50b fixed to the housing 90, and a linkage mechanism as described above, wherein one moving contact can come into contact with or be separated from one static contact.

[0028] The use of such a linkage mechanism will further increase the switching device's ability to switch on or off, as well as its electrical lifespan.

[0029] To limit the movement of the drive rods to within a preset range, in one embodiment of the present invention the switching device may also comprise limiting mechanisms 91 and 92 disposed on the housing; the limiting mechanisms 91 and 92 can limit the rotation angle of the drive rods. In particular, the limiting mechanisms may be a pair of protrusions located at two ends of the center. When the drive rods rotate to a specific angle, they will be obstructed by the protrusions, so that the possibility of further rotation is limited. When the switching device is in a disconnected state, the moving contacts are not in contact with the static contacts, while the drive rods are in contact with the limiting mechanisms.

[0030] The process of the switching device changing from the ON to the OFF position is illustrated by Figs. 5, 4 and 3 in that order. Thus, when the switching device reaches the OFF position, drive rod 10a will be obstructed by limiting mechanism 91, while drive rod 10b will be obstructed by limiting mechanism 92, so that the possibility of further rotation is limited.

[0031] In this text, "schematic" means "serving as a real instance, example or illustration". No drawing or embodiment described herein as "schematic" should be interpreted as being a more preferred or more advantageous technical solution.

[0032] The series of detailed explanations set out above are merely specific explanations of feasible embodiments of the present invention, which are not intended to limit the scope of protection thereof. All equivalent embodiments or changes made without departing from the artistic spirit of the present invention should be included in the scope of protection thereof.

Claims

1. A linkage mechanism of a switching device, characterized in that it comprises
a drive shaft (10) which is capable of rotating around its center (P) and has a pair of drive rods (10a, 10b),
two moving contacts (30a, 30b) which are arranged in parallel and are centrosymmetric with respect to the center (P), the moving contacts (30a, 30b) being capable of rotating around respective fixed pivot points,
and two connecting rods (20a, 20b) which are centrosymmetric with respect to the center (P), the two ends of each of the connecting rods (20a, 20b) being pivotably connected to one end of the drive rod (10a, 10b) and one of the moving contacts (30a, 30b), respectively.

2. A switching device, characterized in that it comprises
a housing (90),
two static contacts (50a, 50b) fixed to the housing (90), and the linkage mechanism as claimed in claim 1, wherein the moving contact (30a, 30b) can come into contact with or be separated from one of the static contacts (50a, 50b).

3. The switching device as claimed in claim 2, characterized in that it further comprises a limiting mechanism (91, 92) disposed on the housing, the limiting mechanism (91, 92) being capable of limiting the rotation angle of the drive rods (10a, 10b).

4. The switching device as claimed in claim 2, characterized in that the limiting mechanism is a pair of protrusions located at two ends of the center (P).

5. The switching device as claimed in claim 4, characterized in that when the switching device is in a disconnected state, the moving contacts (30a, 30b) are not in contact with the static contacts (50a, 50b), and the drive rods (10a, 10b) are in contact with the limiting mechanism.

6. The switching device as claimed in claim 2, characterized in that the switching device is an isolating switch.

Drawing