Micro-switch and method of manufacture

Abstract

An electric micro-switch has at least one electric contact. The contact has a profiled section. The profiled section has a longitudinal extension, a bent portion formed in the longitudinal extension and having an outer surface that is, at least in section, formed in a rounded manner. A contact region is defined on the outer surface of the bent portion. A method for manufacturing the micro-switch is also disclosed.

Claims

1. An electric micro-switch comprising a switching mechanism having two stationary electric contacts and at least one counter contact engaged in a spring holder, wherein each stationary contact has a profiled section, and the profiled section has a longitudinal arched extension, a bent portion formed in the longitudinal arched extension and having an outer surface that is, at least in section, formed in a rounded manner, and a contact region defined on the outer surface of the bent portion, a longitudinal direction of the two stationary electric contacts is transverse to a longitudinal direction of the counter contact, the two stationary electric contacts and the spring holder are not coplanar, and a longitudinal extension of the counter contact is perpendicular to the longitudinal extension of the stationary electric contact.

2. The micro-switch of claim 1, wherein each contact is manufactured from a solid material.

3. The micro-switch of claim 2, wherein each contact is a stamped component.

4. The micro-switch of claim 1, wherein the counter contact has planar contact region.

5. The micro-switch of claim 1, wherein a layer of an electrically conductive material is applied to each contact region.

6. The micro-switch of claim 5, wherein the electrically conductive material is a precious metal.

7. The micro-switch of claim 5, wherein the electrically conductive material is carbon.

8. A method for manufacturing the micro-switch of claim 1, comprising the steps of: stamping the at least one contact out of an electrically conductive material and embossing its contact region; coating the contact region of the or each contact with an electrically conductive material in liquid phase; and inserting the contact into a switch housing, after the electrically conductive material has hardened.

9. The method of claim 8, further providing at least one counter contact having a planar contact region and coating the planar contact region with an electrically conductive material in liquid phase.

10. The method of claim 8, wherein coating the contact region of the or each contact with the electrically conducting material is carried out in an immersion process.

11. The method of claim 8, wherein plating the contact region of the or each contact with the electrically conducting material is carried out in an spraying process.

12. The method of claim 11, including by using at least one inkjet printer for the spraying process.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A preferred embodiment of the invention will now be described, by way of example only, with reference to figures of the accompanying drawings. In the figures, identical structures, elements or parts that appear in more than one figure are generally labeled with a same reference numeral in all the figures in which they appear. Dimensions of components and features shown in the figures are generally chosen for convenience and clarity of presentation and are not necessarily shown to scale. The figures are listed below.

(2) FIG. 1 is a perspective, partially sectioned view of a micro-switch according to the invention,

(3) FIG. 2 and FIG. 3 are perspective views of the electrically conductive components of the micro-switch of FIG. 1, in different switching states;

(4) FIG. 4 and FIG. 5 are perspective views of stamped original components for a contact of the micro-switch of FIG. 1, at different stages of manufacture; and

(5) FIG. 6 and FIG. 7 are perspective views of stamped original components for a counter contact of the micro-switch of FIG. 1 at different stages of manufacture.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) The micro-switch of FIG. 1 comprises an approximately rectangular-shaped construction, it has a trough-like lower part or base 1 and a lid part or housing 2 which is fixed to the base 1. Inside the micro-switch 1 are arranged contacts, i.e. contacts 3, 3 and a counter-contact 4.

(7) FIGS. 2 and 3 show that the contacts 3, 3 comprise contact regions 5, 5, which have a bent portion in their longitudinal extensions. In addition the outer surfaces of the bent contact regions 5, 5 are formed rounded on facing sides.

(8) The counter contact 4 has a planar contact region 6, this is in electrically conducting contact with the upper contact 5 in FIG. 2 and is in electrically conducting contact with the lower contact 5 in FIG. 3. The counter contact 4 is equipped with a snap-action spring 7 and is engaged in a corresponding spring holder 8.

(9) FIGS. 4 and 5 show that contact 3 is formed as a stamped component. The contact 3 is produced by stamping a sheet of conductive material, such as brass, the contact region 5 is formed by an embossing process. The embossing process leads to the dual arching in the contact region 5.

(10) The contact region 5 is plated with an electrically conductive material 9. This material 9 may be a precious metal or may have a carbon basis. This material 9 may be applied by immersing, spraying, printing or the like. Preferably it is applied using an ink jet printer.

(11) Contact 5 is made in a similar manner.

(12) FIG. 6 and FIG. 7 show that the counter contact 4 is also a stamped component, the contact region 6 of which is plated with the electrically conductive material 9. Preferably, the material of the counter contact 4 is a sheet spring conductive material such as beryllium copper.

(13) As described above and shown in the Figures, the stationary contact(s) and the moving contact achieve a point contact by design, in a simple cost effective manner.

(14) The moving contact is formed of a leaf-spring which following manufacture is essentially flat. Its functional partially bent shape is created during assembly.

(15) The stationary contact is formed by a narrow stamped section, which is arched in two planes. This form is preferably produced in the stamping tool by bending and embossing. Due to these simple forms the contacts are able to touch in an optimal point-like fashion (an elliptical flattening is created during touching), wherein the point-like touching is maintained even for large angular deviations.

(16) The aim is to achieve a high degree of material hardness of the basic contact bodies involved and the contact layers applied. The rolling process for manufacturing the punched strips allows the material hardness of the basic body to be set to almost any desired (high) level. The bending and embossing process carried out on the stationary contact supports the increase in hardness precisely in the contact area.

(17) Vibrations (bouncing) are prevented by a further reduction in the mass moved during the switching jump. In addition the pressure of the actuator acts upon the leaf spring in a vibration-dampening manner.

(18) For large series production the most economic process is that of electroplating using belts which carry the components to be plated. The simplest method of selectively plating belts comprises partially immersing the moving belt in a galvanic bath, with a current between the belt and the bath. The design of the contacts permits them being embedded in stamping belts, where, save for the parts required for the function, no further parts are wetted in the bath and where thus no unnecessary areas are coated. Compared to complete dipping the amount of precious metal required is less.

(19) This design of the contacts and the belt also permits coating by immersing the moving belt in non-galvanic baths.

(20) If a further reduction in precious metal is desired, one-sided coating is possible.

(21) To further reduce the precious metal content, a solid layer of carbon may be applied with only the opposite contact being coated with precious metal.

(22) Optionally, the contact surfaces may be formed solely of carbon while completely omitting the precious metal.

(23) In the description and claims of the present application, each of the verbs comprise, include, contain and have, and variations thereof, are used in an inclusive sense, to specify the presence of the stated item or feature but do not preclude the presence of additional items or features.

(24) It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

(25) The embodiments described above are provided by way of example only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined by the appended claims.