WO2014205685A1

WO2014205685A1 - Contact system for cam switch and a cam switch including the same

Info

Publication number: WO2014205685A1
Application number: PCT/CN2013/078019
Authority: WO
Inventors: Qishun GUO
Original assignee: Abb Oy
Priority date: 2013-06-26
Filing date: 2013-06-26
Publication date: 2014-12-31

Abstract

A contact system is provided. The contact system includes a fixed contact (20); a moving contact (10) configured to be in connection with or released from the fixed contact; a contact carrier (30) having a first side and a second side and movably carrying the moving contact at the second side; a cam (40) configured to press the contact carrier from the first side; and a spring (50) configured to press the contact carrier from the second side through the moving contact, wherein the contact carrier has an arc portion at the second side to be in contact with the moving contact. A cam switch including the contact system is also provided. The contact system can lower the possibility that the moving contact is side-tumbled or offset, promote the elimination of the heat, reduce the temperature, and decrease the possibility of fusion welding with the simple structure and high performance.

Description

CONTACT SYSTEM FOR CAM SWITCH AND A CAM SWITCH

INCLUDING THE SAME

FIELD OF INVENTION

[00011 The invention relates to a contact system for cam switch and a cam switch including the same.

BACKGROUND OF INVENTION

[0002] Currently double-tips and align-moving contact system is widely used in cam switches since it has better performance, simpler assembly process, takes smaller space and is easier for manufacturing.

[0003] However, traditional contact system for cam switch is likely to be side-tumbling or offset, which will easily bring one-side fusion welding, since there is lateral force acting on contact carrier by cam. There were two solutions in the past: adding one wheel in front of the contact carrier or making the moving contact thinner to have some flexibility. The former structure has a rather complex structure, which is hard to be applied in small cam switch such as cam switch of 25A or lower. The latter will increase contact resistance, and may cause structural failure due to shape change after long time running.

SUMMARY OF INVENTION

[0004] It is therefore a general object of the present invention to overcome the aforementioned disadvantage. It's fire-new auto- adjustable double-tips and align-moving contacts system. Fire-new carrier 3 is designed and drives the contacts system work as a level mechanism.

[0005] The present application provides a contact system for cam switch, including a fixed contact; a moving contact configured to be in connection with or released from the fixed contact; a contact carrier having a first side and a second side and movably carrying the moving contact at the second side; a cam configured to press the contact carrier from the first side, and a spring configured to press the contact earner from the second side through the moving contact, wherein the contact carrier has an arc portion at the second side to be in contact with the moving contact.

[0006] In one embodiment, the arc portion is at center of the second side, and chord length of the arc portion is about 50% to 70% of width of the second side.

[0007] In another embodiment, the contact carrier is configured to be in arc at the whole second side.

[0008] In a further embodiment, the contact system includes a pair of fixed contacts, and the moving contact is configured to be in connection with or released from the pair of fixed contacts at two ends of the moving contact, and the contact carrier and the spring bring forces onto the moving contact at a place between the two ends.

[0009] The present application further provides a cam switch including any of the above contact system.

[0010] In one embodiment, the cam switch includes two contact systems as described above, and the cam is commonly used by the two contact systems.

[0011] In one embodiment, the cam switch includes several chambers stacked on each other, and one or more contact systems described above are included in each of the several chambers.

[0012] The structures provided herein can lower the possibility that the moving contact is side-tumbled or offset, promote the elimination of the heat, reduce the temperature, and decrease the possibility of fusion welding, with the simple structure and high performance,

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The subject matter of the invention will be explained in more detail in the following text with reference to preferred exemplary embodiments which are illustrated in the drawings, in which:

[0014] Fig. 1 shows a contact system and a cam switch employing the same according to one embodiment of the present application.

[0015] Fig. 2 shows a perspective view of a contact earner according to one embodiment of the present application. [0016] Fig. 3 shows a cross-section of a contact carrier according to one embodiment of the present application.

[0017] Fig. 4 shows, among others, cross-section of a contact carrier according to one embodiment of the present application and its usage.

[0018] Fig. 5 shows, among others, cross-section of a contact carrier according to another embodiment of the present application and its usage.

[0019] Fig. 6 shows, among others, cross-section of a contact carrier according to a further embodiment of the present application and its usage.

[0020] Throughout the figures, same or similar reference numbers indicate same or similar elements. In principle, identical parts are provided with the same reference symbols in the figures.

DETAILED DESCRIPTION OF EMBODIMENTS

[0021] It should be appreciated that, while this specification contains many specific implementation details, they should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub -combination or variation of a sub- combination.

[0022] Hereinafter, exemplary embodiments will be referred to in describing the mechanism and spirit of the present invention. It should be understood that these embodiments are merely provided to facilitate those skilled in the art in understanding and in turn implementing the present invention, but not for limiting the scope of the present invention in any way. [0023] Fig. 1 shows a contact system and a cam switch employing the same according to one embodiment of the present application. The contact system includes a moving contact 10, a fixed contact 20, a contact carrier 30, a cam 40, and a spring 50. The moving contact 10 is carried by the contact carrier 30 which is pushed by cam 30 at one side, and is pressed through the moving contact 0 at the other side. Through the cam 30 and the spring 50, the moving contact 10 can be in connection with the fixed contact 20 or released therefrom. As shown in Fig. 1, each moving contact 10 can be in connection with two fixed contacts 20 at two ends of the moving contact 10, and the contact carrier 30 and the spring 50 bring forces onto the moving contact 10 at somewhere between its two ends, preferably around center of the moving contact 10.

[0024] When the cam 40 is rotated clockwise by a handle (not shown), with the matching profile between the contact carrier 30 and cam 40, the contact carrier 30 on right side (the contact carrier 30 on left side will not be repeatedly described here since the principle is same) is driven by the force FL exerted through the cam 40, which can be divided into two components, i.e. a lateral component and a vertical component. While the lateral component will try to overcome the force from spring 50 so as to move the moving contact rightward, the contact earner 30 will tend to side-tumble under the vertical component. However, since it is the arc portion of the side 3 IB which is in line-to-line contact with the moving contact 10, the friction is much smaller than the vertical component. By having all these effects together, the contact carrier 30 will come to a balanced position by itself without having the moving contact 10 side-tumbled or offset. In addition, when the current or voltage is high enough, the repulsive force brought by contacting the moving contact 10 and the fixed contact 20 or the attractive force brought by releasing therebetween will expedite the self-adjustment of the moving contact 10.

[0025] Fig. 2 shows a perspective view of the contact carrier 30 according to one embodiment of the present application, and Fig. 3 shows a cross-section of the contact carrier 30. As shown in Fig. 2 and Fig. 3, the contact carrier 30 includes a post 31 , an upper stopper 32 and a lower stopper 33. In use, a cam is putting at one side 31 A, which has a matching profile with the cam, of the post 31 , and a moving contact is putting at the opposite sides 3 IB of the post 31, so that rotation of the cam can be finally transformed to linear movement of the moving contact. According to present application, the opposite side 3 IB is formed to have an arc portion to contact the moving contact, which is pressed by the spring 50. The upper stopper 32 and lower stopper 33 can restrict the movement of moving contact in up-and-down direction. The upper stopper 32 and lower stopper 33 can be an integrated with the post 31 to form an integrated contact carrier 30.

[0026] In addition, the new contact carrier 30 decreases the interface between itself and moving contact 10. This will promote elimination of the heat, reduce the temperature, and decrease the possibility of fusion welding, with the simple structure and high performance. It will also not increase the yield cost or contact resistance, and can be used in small cam switches.

[0027] Fig. 6 and Fig. 7 show another two embodiments of the contact carrier 30. As shown in Fig. 6, the post 31 could be cylindrical, or side 3 IB of the post 31 could be in a half-cylinder shape. As shown in Fig. 7, arc portion of side 3 IB could occupy almost the whole extension of side 3 IB. It should be understood that the size and shape of arc portion can be varied based on specific requirement.

[0028] In a preferred embodiment, the arc portion is in the center of side 3 IB, and chord length of the arc portion is at 50%-70% of the whole extension of side 3 IB. With this structure, the remaining part next to the arc portion of side 3 IB can limit the utmost rotation of the moving contact 10.

[0029] It should be understood that although Fig. 1 shows a two-element, double-tips and align-moving contact system, the structure shown can also be applied on other contact systems such as three- element, double-trips and align-moving contact system. The cam switch can also include several chambers stacked on each other, each of which can include one or more contact systems. In addition, the cam switch can include one or more cams, and notches on the cam can be adjusted to meet different requirement. For example, one cam can be commonly used by two contact systems, and the notches on the cam can be different from what is shown in Fig. 1 so that the timing and manner of connecting or releasing the fixed contact and the moving contact can be set as required.

[0030] 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 way limit the scope of the present invention. Without departing from the spirit and concept of the present invention, any variations and modifications to the embodiments should be within the apprehension of those with ordinary knowledge and skills in the art, and therefore fall in the scope of the present invention which is defined by the accompanied claims.

Claims

1. A contact system for cam switch, including

a fixed contact;

a moving contact configured to be in connection with or released from the fixed contact;

a contact carrier having a first side and a second side and movably carrying the moving contact at the second side;

a cam configured to press the contact carrier from the first side, and

a spring configured to press the contact carrier from the second side through the moving contact,

wherein the contact carrier has an arc portion at the second side to be in contact with the moving contact.

2. The contact system according to claim 1 , wherein

the arc portion is at center of the second side, and chord length of the arc portion is about 50% to 70% of width of the second side.

3. The contact system according to claim 1, wherein

the contact carrier is configured to be in arc at the whole second side.

4. The contact system according to any one of claims 1 to 3, wherein

the contact system includes a pair of fixed contacts, and the moving contact is configured to be in connection with or released from the pair of fixed contacts at two ends of the moving contact, and the contact carrier and the spring bring forces onto the moving contact at a place between the two ends.

5. A cam switch including a contact system according to any one of claims 1 to 4.

6. The cam switch according to claim 5, wherein the cam switch includes two contact systems according to any one of claims 1 to 4, and the cam is commonly used by the two contact systems.

7. The cam switch according to claim 5, wherein the cam switch includes several chambers stacked on each other, and one or more contact systems according to any one of claims 1 to 4 are included in each of the several chambers.