EP0533138A2

EP0533138A2 - Switch

Info

Publication number: EP0533138A2
Application number: EP92115850A
Authority: EP
Inventors: Mitsuo Aimi
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 1991-09-17
Filing date: 1992-09-16
Publication date: 1993-03-24
Also published as: CA2078350A1; JP2924353B2; TW221515B; EP0533138A3; JPH0574269A

Abstract

In a switch to be used in commercial or industrial electronics, at least two, preferably three, tongued plate spring parts (4a, 4b, 4c) are formed on one switching member (4) in a manner that one (4c) of the tongued plate spring parts is extended from one base part (4j) and the other (two) tongued plate spring part(s) (4a, 4b) is/are extended from the other base part (4i), and at least two, preferably three, bent concave coupling parts (31a, 31b, 31c) which are to be coupled with the tongued plate spring parts (4a, 4b, 4c) are formed on a common terminal (3).

Description

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

The present invention relates to an improvement of a switch which is to be used in consumer's or industrial electronics.

2.DESCRIPTION OF THE PRIOR ART

A conventional switch wherefrom the present invention starts is described referring to FIGs. 3(a) and 3(b). FIG.3(a) is a sectional side view showing a constitution of the conventional switch. FIG.3(b)is a perspective view showing the main part of the conventional switch.
In FIG.3(a), on a bottom 11a of an insulation case 11, an individual terminal 12 and a common terminal 13 are fixed. On the individual terminal 12, contact 14 is fixed. As shown in FIGs. 3(a) and 3(b), an end 18a of a bent plate spring 18 and an end 17a of a bent first switching member 17 are coupled in concave corners 13a and 13b on the common terminal 13, in rotatable. The other ends 17b and 18b of respective of the plate spring 18 and the first switching member 17 are coupled with channel section parts 16a and 16b of another (second) switching member 16, in rotatable. The couplings of the plate spring 18 with the common terminal 13 and the first switching member 17 with the second switching member 16 are maintained by pressures produced by the plate spring 18, respectively. As shown in FIG.3(a), a sliding member 19 couples with a top end of the channel-section part 16a of the second switching member 16 at a concave part 19c and most portion of the sliding member 19 is slidingly contained in the insulation case 11. A guide frame 20 is fixed on the insulation case 11 for guiding a top faces 19a of the sliding member 19. A coil spring 21, which supplies an elastic force for restoring the sliding member 19 to an initial position, is provided on a concave part 19b formed between the sliding member 19 and the insulation case 11.
Motion of the above-mentioned conventional switch is described referring to FIGs. 4(a), 4(b) and 4(c). FIGs.4(a) to 4(c) are sectional side views of the main part of the conventional switch. In FIG.4(a), the conventional switch is an "OFF" state. When the sliding member 19 is moved in a direction shown by arrow "f" as shown in FIG.4(b), the top end of the channel-section part 16a of the second switching member 16 which is engaged with the concave part 19c of the sliding member 19 is moved in the same direction shown by arrow "f". The "off" state of the conventional switch, however, is maintained until a straight line AC, which is defined by connecting two points A and C, crosses a point B, where the point A is the coupling point of the second switching member 16 and the plate spring 18, the point C is the coupling point of the first switching member 17 and the second switching member 16 and the point B is the coupling point of the common terminal 13 and the first switching member 17.
When the sliding member 19 is further moved in the direction shown by arrow "f" and the straight line AC crosses over the point B thereby coming to the left side of the point B, the lower channel-section part 16b of the second switching member 16 moves to the left hand in the figure as shown in FIG.4(c). And thereby, the contact 15 on the second switching member 16 contacts the contact 14 on the individual terminal 12. As a result, the conventional switch turns to "on" state from the "off" state.
The above-mentioned conventional switch has a snap-action contact mechanism. When the conventional switch is turned "on" and "off", the moving members such as the first and second switching members 17 and 16 and the plate spring 18 are moved reversely to each other. And especially, it is known that such the conventional switch is very reliable as a power switch of the electronic apparatus in respect of arc-resistance, antiwelding performance and the like. The conventional switch, however, has a complex constitution since it needs, for example, four metal piece members 13, 16, 17 and 18. And thereby, it needs many elements and many assemble processes, and hence it is very expensive.
Furthermore, in the conventional switch, the common terminal 13, the first and second switching members 17 and 16 and the plate spring 18 serve as a path for an electric current. Therefore, there are many coupling points in the current path, for example, points A, B and C between the elements. Thus, contact resistances at these coupling points become a cause of heating of the switch.

SUMMARY OF THE INVENTION

Purpose of the present invention is to provide an improved switch having a simple configuration and to reduce the number of elements constituting the switch.
A switch in accordance with the present invention comprises:
a casing, major part thereof being made of an insulation material;
at least an individual terminal fixed on the casing and having a stationary contact fixed thereon;
a common terminal fixed on the casing insulatedly departed from the individual terminal and having at least two concave coupling parts, one of the bent coupling part opposing to the other;
a switching member having a contact, a first and second base parts, the first and second base parts being held by a relatively rigid frame part and at least two parallel plate spring parts to be coupled with the bent concave coupling parts of the common terminal, respectively, one of the plate spring part being extended from a first base part and the other being extended from a second base part, the contact being fixed on the first or second channel-section part in a manner to face said contact on the individual terminal;
a moving member having a concave part to be coupled with an end of the first or second base part of the switching member which is not facing to the contact on the individual terminal; and
a spring member for supplying a force to the moving member to return to an initial position of the moving member.
In the switch in accordance with the present invention as configured above, for example, three tongued plate spring parts are formed on one switching member in a manner that one of the tongued plate spring part is extended from one of the base part and the other two tongued plate spring parts are extended from the other base part. And that the three bent concave parts which are to be coupled with the tongued plate spring parts are formed on the common terminal. As a result, the numbers of the elements constituting the switch in accordance with the present invention becomes small. For example, only two metal pieces are enough. And the assemble steps of the switch in accordance with the present invention are much reduced in comparison with those of the conventional switch.
Furthermore, in the present invention, the numbers of the metal parts constituting the current path are reduced from that of the conventional switch. And thereby, the contact resistance at the coupling points of the metal parts become smaller than that of the conventional one. As a result, the heating of the switch in accordance with the present invention is reduced.
While the novel features of the invention are set forth particularly in the appended claims, the invention, both as to organization and content, will be better understood and appreciated, along with other objects and features thereof, from the following detailed description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG.1(a) is a sectional side view showing a first embodiment of a constitution of a switch in accordance with present invention.
FIG.1(b) is a perspective view showing a main moving part of the switch of the first embodiment.
FIGs. 2(a), 2(b) and 2(c) are respectively sectional side views showing motion of the main moving part of a switch in accordance with the present invention.
FIG.3(a) is the sectional side view showing the constitution of the conventional switch.
FIG.3(b) is the perspective view of the main part of the conventional switch.
FIGs. 4(a), 4(b) and 4(c) are respectively sectional side views showing the motion of the main moving part of the conventional switch.
It will be recognized that some or all of the Figures are schematic representations for purposes of illustration and do not necessarily depict the actual relative sizes or locations of the elements shown.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A preferred embodiment of a switch in accordance with the present invention is described referring to FIGs. 1(a) and 1(b). FIG.1(a) is a sectional side view showing a constitution of the first embodiment of the switch. FIG.1(b) is a perspective view showing a main part of the switch shown in FIG.1(a).
In FIG.1(a), an individual terminal 2 and a common terminal 3 are fixed on a bottom 1a of an insulation case 1. A contact 5 is fixed on the individual terminal 2. A switching (cradle) member 4, which is made of a resilient conductive material (metal) having a characteristics suitable for a plate spring, is coupled with the common terminal 3. As shown in FIG.1(b), the switching member 4 has three tongued plate spring parts (leaf springs) 4a, 4b and 4c which are disposed parallel to each other, one of them 4c being extended from an upper (first) base part (channel-section part) 4j and the others 4a and 4b being extended from the other lower (second) base part (channel section part) 4i. The upper and lower base parts 4i and 4j are held by frame parts 4h which are relatively rigid. End parts 4d, 4e and 4f of the tongued plate spring parts 4a, 4b and 4c are coupled with bent concave corners 31a, 31b and 31c of a coupling part 31 of the common terminal 3 in a manner that respective tongued plate spring parts 4a, 4b and 4c are distorted to produce predetermined contact pressures. As shown in FIG.1(b), a sliding member 8 has a concave part 8a with which an upper end part 4g of the upper channel-section part 4j of the switching member 4 is to be coupled. Most portion of the sliding member 8 is slidingly contained in the insulation case 1. A guide frame 7 is fixed on the insulation case 1 for guiding a top face 8b of the sliding member 8. A coil spring 9, which supplies an elastic force for returning the sliding member 8 to an initial position, is provided on a concave part 8c formed between the sliding member 8 and the insulation case 1.
Motion of the switch of the above-mentioned first embodiment in accordance with the present invention is described referring to FIGs. 2(a), 2(b) and 2(c). FIGs. 2(a) to 2(c) are respectively sectional side views showing the motion of the main moving part of the switch.
In FIG.2(a), the switch in accordance with the present invention is an "off" state. When the sliding member 8 is moved in a direction shown by arrow "f" as shown in FIG.2(b), the top end 4g of the upper channel-section part 4j of the switching member 4 which is engaged with the concave part 8a of the sliding member 8 is moved in the same direction shown by arrow "f". The "off" state of the switch, however, is maintained until a straight line AC which is defined by connection of the points A and C crosses a point B, wherein the points A and c are respectively the coupling points of the tongued plate spring parts 4c and 4a/4b and the point B is the coupling point of the tongued plate spring part 4a or 4b and the bent concave part 31a or 31b of the coupling part 31.
When the sliding member 8 is further moved in the direction shown by arrow "f" and the straight line AC crosses over the point B, the lower channel-section part 4i of the switching member 4 is moved to the left hand in the figure as shown in FIG.2(c). And thereby, the contact 6 on the switching member 4 snappingly touches the contact 5 on the individual terminal 2. As a result, the switch in accordance with the present invention turns to "on" state from the "off" state. For turning off the above-mentioned switch from the "on" state, the main moving parts of the switch move snappingly in a manner inverse to the above-mentioned motion.
Although the present invention has been described in terms of the presently preferred embodiments, it is to be understood that such disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.

Claims

A switch comprising:
a casing (1), major part (1a) thereof being made of an insulation material;
at least an individual terminal (2) fixed on said casing and having a stationary contact (5) fixed thereon;
a common terminal (3) fixed on said casing insulatedly departed from said individual terminal (2) and having at least two concave coupling parts (31a,31b,31c), one of said bent coupling part opposing to the other;
a switching member (4) having a contact (6), a first and second base parts (4i,4j), said first and second base parts being held by a relatively rigid frame part (4h) and at least two parallel plate spring parts (4a,4b,4c) to be coupled with said bent concave coupling parts (31a,31b,31c) of said common terminal (3), respectively, one of said plate spring part (4c) being extended from a first base part (4j) and the other (4a,4b) being extended from a second base part (4i), said contact (6) being fixed on said first or second base part in a manner to face said contact (5) on said individual terminal (2);
a moving member (8) having a concave part (8a) to be coupled with an end (4g) of said first or second base part (4j) of said switching member (4) which is not facing to said contact (5) on said individual terminal (2); and
a spring member (9) for supplying a force to said moving member (8) to return to an initial position of said moving member.