JPH0520991A - Switching mechanism of electric contact - Google Patents

Abstract

PURPOSE:To facilitate adjusting contact pressure while simplifying an adjusting mechanism by having a bimetallic member for supporting a contact portion, and the center of rotation and a lever portion, both united with the bimetallic member. CONSTITUTION:A stationary-contact side bimetallic-member 2 whereto a stationary-side contact 1 is welded is positioned by the dowels 4, 5 of a lead frame 3, and then it is caulked or welded so as to be fixed to the lead frame. Then a hole forming the center of rotation is formed in a movable-contact side bimetallic-member 8 whereto a movable-side contact 7 is welded, and the member is fitted into the dowel 9 of a lead frame 10 via the hole. Then the contact 7 is rotated round the dowel 9 by pushing the apex 12 of the bimetallic member 8 at its lever portion, it is pushed into a space between the contact 1 and the bimetallic member so that the contact 1 may have its predetermined contact-pressure upon the contact 7, welding by resistance, or laser or the like is given to the spot of a weldingly fixing portion 11 so that the bimetallic member may be fixed to the lead frame 10. The lead frames 10 and 3 have been already fixed to the insulating member of a base 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact pressure adjusting mechanism of an electric switching device, and more particularly to a mechanism of a low contact pressure electric switching device for opening and closing contacts by Joule heat using a bimetal material.

[0002]

2. Description of the Related Art Generally, as a contact pressure adjusting mechanism,
Either one of the contacts is fixed, and a method of adjusting the feeding of the screw by forming the other contact to the bolt shape, molding the arm that supports the advance either one contact to impart a spring property, the spring force Methods of generating contact pressure are known.

In order to obtain the desired contact pressure by the screw method, the arm is bent by a tool such as a screwdriver or wrench on the input side when a bolt is fed to the arm made of bimetal material with a nut. The bolt must be sent to prevent it from being sent, which makes it difficult to feed.

Also, since the bolts and nuts play, delicate adjustments cannot be made. Also, even if it is fixed after adjustment,
Generally, the fixing method by adhesion takes a long time to fix, and the adjustment position is displaced during the fixing. In addition, due to the high heat during use, the adjustment force is reduced due to a decrease in the adhesive fixing force.

Further, in the method of adjusting the contact pressure by the spring force without using a screw, the molding accuracy at the time of spring molding and the processing accuracy of a member to which the spring is mounted influences the contact position accuracy after mounting, and requires a fine adjustment. It is difficult to use the one with low contact pressure.

[0006]

In the above-mentioned prior art, the low pressure contact is difficult to work such as play of the screw, screwing at the time of adjustment, and adhesion at the time of fixing, so that it should be incorporated in a high-speed assembly line. Was difficult.

It is an object of the present invention to provide an arm supporting a contact and a rotation center and a lever portion for moving the contact which are integrated with the arm for supporting the contact without moving the contact by a screw, thereby simplifying the adjusting mechanism. It is to facilitate the method of adjusting the pressure.

[0008]

The above object is achieved by pressing the apex of the lever portion by adjusting the contact pressure by providing a bimetal material that supports the contact portion, a rotation center and a lever portion that are integral with the bimetal material. It is achieved by fixing the lever portion by caulking or welding after the adjustment.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

The fixed contact side bimetal material 2 obtained by welding the fixed side contact 1 shown in FIG. 1 is positioned by the dowels 4 and 5 protruding from the lead frame 3 and fixed to the lead frame 3 by caulking or welding. Further, it is fixed to the insulating material of the base 6. Next, a hole serving as the center of rotation is formed in the movable contact-side bimetal material 8 in which the movable-side contact 7 is fixed by crimping or welding, and the dowel serving as the center of rotation of the movable contact-side bimetal material 8 protruding from the lead frame 10 is formed. Set in 9. Then, by pressing the apex 12 of the lever portion of the movable contact-side bimetal member 8, the movable-side contact 7 is rotated around the dowel 9 and brought into contact with the fixed-side contact 1, and further pushed in to obtain welding at a predetermined contact pressure. The movable contact side bimetal member 8 is fixed to the lead frame 10 at the fixed portion 11 by welding such as resistance or laser.

Further, by making the length from the dowel 9 as the center of rotation to the apex 12 of the lever portion shorter than the length from the dowel 9 as the center of rotation to the movable side contact 7, a large amount of movement is possible with a small amount of pushing. The amount can be obtained, which can contribute to shortening the adjustment time of the contact pressure having a relatively high pressure.

On the contrary, by making the length from the dowel 9 as the center of rotation to the apex 12 of the lever portion longer than the length from the dowel 9 as the center of rotation to the movable contact 7.
Since the amount of movement of the contact can be made smaller than the amount of pushing and positioning can be performed with high accuracy, it is possible to easily adjust the contact with a relatively low contact pressure and high responsiveness.

[0013]

Since the electrical contact switching mechanism according to the present invention has the above-described structure, by adopting such a mechanism, compared with the conventional method in which the screwdriver groove of the bolt is searched and then rotated and adjusted. Since the adjustment can be made by simply moving the terminal that is in contact with the apex of the lever portion straight, the mechanism of the adjusting machine is simplified and the adjusting time is shortened.

Further, the bolt 15 formed of the contact material required by the conventional method shown in FIG. 3 and the nut 1 supporting the bolt 15 are formed.
6 becomes unnecessary, and both the parts processing cost and the assembly cost can be reduced.

Further, it is possible to form the work material in which the contact material is seam-welded in advance to the bimetal material by press working, so that the cost can be greatly reduced.

In addition, the lever portion can be fixed by welding or caulking by resistance or laser, etc. after fixing by adhesion after adjustment, and the fixing speed can be increased and the reliability of the fixing portion can be improved.

As described above, high quality products can be obtained at low cost.

[Brief description of drawings]

FIG. 1 is a front view of a switching mechanism according to the present invention.

FIG. 2 is a side view of a switching mechanism according to the present invention.

FIG. 3 is a front view of a conventional switching mechanism.

[Explanation of symbols]

 1 Fixed Side Contact 2 Fixed Contact Side Bimetal Material 3 Lead Frame 4 Dowel 5 Dowel 6 Base 7 Movable Side Contact 8 Movable Contact Side Bimetal Material 9 Dowel 10 Lead Frame 11 Weld Fixed Part 12 Lever Point 13 Fixed Side Contact 14 Fixed Contact Side bimetal material 15 Bolts formed from contact material 16 Nuts 17 Moving contact side bimetal material

Claims (1)

Claim: What is claimed is: 1. An electric contact switching mechanism having a mechanism for opening and closing by heat generation using a bimetal material for a contact or a member for supporting the contact, the contact pressure being adjusted to one of the two contacts. A switching mechanism for electrical contacts, characterized by having a hole or dowel as a center of rotation for moving the contact position and a lever part integrated with a contact part for transmitting a force from the outside during movement.