JPH04133216A - Mercury contact switch - Google Patents

Abstract

PURPOSE:To suppress occurrence of the sticking phenomenon without causing enlargement of the effective wetting area by providing a composite plating member on the contact piece side. CONSTITUTION:The surface of a contact piece 4 is covered with composite plating, etc., and its moving contact 4a thus consists of composite material, and a part 8 unwetted with mercury 5 is produced. Therefore, the effective wetting area does not enlarge, and sticking phenomenon of a stationary contact 3 and the contact piece 4 to each other through mercury 5 will not occur easily, and the opening motion is conducted easily. The surface of contact piece shall preferably be covered with a composite plating film, in which particulates of metal oxide, etc., are dispersed in a metal matrix of Ni, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mercury contact switch, and more particularly to a mercury contact switch whose contact surface is treated.

[Conventional technology]

A conventional mercury contact switch has a fixed electrode and a movable electrode, and a contact whose surface is plated with nickel is coupled to the tip of the movable electrode.

FIGS. 2(a) to 2(c) are sectional views of a fixed electrode and a contactor inside a mercury contact switch, and sectional views during pre-closing and opening operations of a mercury contact switch, respectively, showing an example of such a conventional switch.

As shown in FIG. 2(a), a conventional mercury contact switch has a pair of fixed electrodes 2 having a fixed contact 3 made of Pt-Ni material at the tip, and a movable electrode (not shown) in a sealed container. A contactor 4 made of Fe--Ni material is connected to the tip of a fixed movable electrode, and mercury and gas are sealed inside. Moreover, the surface of the fixed contact 3 is mercury 5.
The surface of the contact 4 that comes into contact with the mercury 5 is covered with a nickel-plated movable contact 4b that, like the fixed contact 3, is easily wetted by mercury.

Furthermore, as shown in FIG. 2<b>, when the movable contact 4b of the contactor 4 closes with the fixed contact 3 of the fixed electrode 2, both the fixed contact 3 and the movable contact 4b become easily wetted by the mercury 5. There are people there, so make sure to contact them.

Furthermore, as shown in FIG. 2(c), when the contactor 4 is released from the fixed contact 3 of the fixed electrode 2, due to the adhesiveness of the mercury 5, the mercury 5 cannot be cut until a certain distance. When the contact reaches a predetermined distance or more, the adhesiveness of the mercury 5 is overcome and the contacts are separated.

[Problem to be solved by the invention]

In the conventional mercury contact switch mentioned above, the surface of the contact is coated with Ni-Sokel plating, which is a metal that is easily wetted by mercury, so the movable contact remains closed for a long time and is subject to high temperatures or continuous vibration. However, the viscosity of the contact area is increased due to the formation of mercury and nickel intermetallic compounds, resulting in a sticking phenomenon between the fixed contact and the movable contact.

[Means to solve the problem]

The mercury contact switch of the present invention includes a sealed container made of an insulating material, a pair of fixed electrodes fixed to the sealed container and each having at least a fixed contact, and a movable electrode arranged opposite to the fixed electrode. In the mercury contact switch, the contactor is formed of a composite plated member.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1(a) and 1(b) are a sectional view of a mercury contact switch and a sectional view of a fixed electrode and a contact inside the switch, respectively, for explaining an embodiment of the present invention.

As shown in FIGS. 1(a) and (b), this embodiment has the following characteristics when compared with the conventional example shown in FIGS. 2(a) to (c) described above.
The difference is that the surface treatment of the contactor 4 is changed from the nickel-plated movable contact 4b to a composite-plated movable contact 4a such as a metal oxide having nickel as a matrix. In other words, in the open state shown in FIG. 2(c) described above, if the contacts are kept closed for a long time, exposed to high temperatures, or subjected to continuous vibration, intermetallic compounds of mercury and nickel, etc. However, in this embodiment, the surface of the contact 4 is made of composite material. By covering the movable contact 4a with plating or the like, a portion 8 that is not wetted by the mercury 5 is created because the movable contact 4a is made of a composite material. Therefore, the effective wetted area does not increase, and the phenomenon of adhesion between the fixed contact 3 and the contactor 4 via the mercury 5 is less likely to occur, and the opening operation is easily performed.

Moreover, the composite plating movable contact 4a that covers the surface of the contact 4 described above can be covered with a metal oxide, a desalinated substance, or a carbide.

〔Effect of the invention〕

As explained above, the mercury contact switch of the present invention can utilize the mercury-unsatisfactory part of the composite material by providing a composite plating member on the contact side, so that the adhesive phenomenon can be prevented without expanding the effective wetting area. It has the effect of suppressing the

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a sectional view of a mercury contact switch and a sectional view of a fixed electrode and a contact inside the switch, respectively, for explaining one embodiment of the present invention, and FIGS. 2(a) to (c). )
These are a cross-sectional view of a fixed electrode and a contact inside a mercury contact switch, and a cross-sectional view of the contact during closing and opening operations, respectively, for explaining an example of a conventional mercury contact switch. DESCRIPTION OF SYMBOLS 1... Airtight container, 2... Fixed electrode, 3... Fixed contact, 4... Contact, 4a... Composite plating movable contact,
5...Mercury, 6...Movable electrode, 7...Enclosed gas.

Claims (1)

[Scope of Claims] 1. A sealed container made of an insulating material, a pair of fixed electrodes fixed to the sealed container and each having at least a fixed contact, and arranged opposite to the fixed electrode and coupled to a movable electrode. What is claimed is: 1. A mercury contact switch having a mercury contact element sealed with mercury and gas, wherein the mercury contact element is formed of a composite plated member. 2. The mercury contact switch according to claim 1, wherein the contact has a surface coated with a composite plating film in which fine powder such as a metal oxide is dispersed and eutectoid in a metal matrix such as nickel.