JPS61185826A - Small switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Al Industrial Field of Application) The present invention relates to an improvement in a small switch that protects electrical equipment from excessive current by interrupting the circuit when excessive current flows.

(1) l Prior art; In the conventional small switch of this type, the sixth
As shown in the figure, the base 11A of the bimetal 11 with the movable contact 12 attached near its free end is connected to the first terminal 13 protruding in and out of the case 14, and the base 11A of the bimetal 11 is connected to the free end 11B of the bimetal 11. One end IS of the bow spring 15
A is engaged so as to apply a biasing force toward the base of the bimetal 11, and the two stable points of the bimetal 11 (line 2 and 2)
(shown by dotted lines), and the movable contact 12 is connected to the second
The terminal 17 is held in pressure contact with the fixed contact 16 attached near the free end, while the movable contact 12 and the fixed contact 16 are separated from each other at the other stable point. In this case, since the arcuate spring 15 applies a biasing force to the bimetal 11 in the base direction, if the junction point between the spring 15 and the bimetal 11 crosses the critical line A even slightly, it immediately moves to another stable position. Since the contact points 12 and 16 are opened and closed by the movement of the bimetal 11 itself, the bimetal itself has only a small amount of springiness.As a result, the bimetal can be used as a bimetal, so it can be used with high resistance objects and can be used with small currents. It has the advantage of being able to obtain something that works.

However, in the above-mentioned switch, since the direction in which the bimetal 11 deforms, that is, the direction of the arrow P, coincides with the opening direction of the contacts 12 and 16, the bimetal 11 gradually deforms and the spring +5 and the bimetal 11 The junction point with is critical, @
Until A K is reached, the contact pressure between contacts 12 and 16 becomes unstable. This has the disadvantage that there is a risk of poor conduction and circuit malfunction.

(C1 point to be solved by the invention; This invention takes into consideration the above-mentioned point, and when the movable and fixed contacts are separated, the deformation force of the bimetal is applied in the contact pressure direction. %1's objective was to obtain this type of highly reliable switch that can maintain a stable contact state between the contacts, and also to purchase and mass-produce each component so that it could be assembled automatically. The purpose of %2 is to obtain an inexpensive device of this type by minimizing the number of parts.

(d) Means for solving the problem; This invention consists of first and second terminals formed by insert molding on an insulating base, an arcuate spring being pulled out from the center of the terminal, and movable at the tip of one side of the moon. The biasing force of the arcuate spring is applied when the plate spring member to which the contact is attached is engaged with the engagement groove formed at two different heights on the upper side of the base of the first terminal. a bimetal is attached to the upper side of the base of the second terminal, and a fixed contact is attached to the free end side of the bimetal so as to be in pressure contact with and opposite to the movable contact. Then, the first
and the second terminal, and the deformation force of the bimetal that occurs when an overcurrent flows is used to cause the leaf spring member to perform a reverse operation, thereby separating the movable and fixed contacts. This is what happens.

(e) Effect; Since the present invention is configured so that the direction of deformation of the bimetal due to overcurrent acts in the direction in which pressure contact force is applied to both the movable and fixed contacts, contact between the contacts is maintained until the two contacts are about to open. The pressure does not weaken and the contact between the contacts 1
'It will be possible to maintain a stable German state. In addition, each part constituting the switch is constructed so that it can be assembled automatically, allowing for mass production and minimizing the number of parts to reduce production costs.

(f) Embodiment; FIG. 1 is a front view of a small switch according to an embodiment of the present invention, and FIG. 2 is the same <plan view, gIJ3
The figure shows an explanatory diagram of the operation.

! In Figure 1, 1 is a resin insulating case whose front jacket is being removed. Reference numeral 2 designates a leaf spring member, in which a substantially rectangular window hole 22 is punched out in its midsection, sandwiching a window hole 20 with a generally U-shaped plane and a bridging piece 21; An arcuate spring 23 is drawn and raised at the portion.

Furthermore, the movable contact 3 is fixed to the free end of one side of the leaf spring member 20 by caulking. Then, the plate spring member 2
is one side of the support part 40 which is protruded in and out of the case, and in which the flat surface of the upper side of the first terminal 4, which is erected in the central part of the insulating base 10, is flattened. Locking i formed on the edge
'I! The proximal end 24 of the leaf spring member is engaged with the spring 24, and the free end 23A of the arcuate spring 23 is engaged with the engagement groove 42 formed on the other side edge. The locking grooves 41 and 42 are formed such that the position of one of the locking grooves 41 is slightly higher than the position of the locking groove 42, and the plate spring member 2 is normally locked to the @l terminal 4. The good news is that the arcuate spring 23 is attached to the plate spring member as shown in Figure 1.
Accordingly, the contact point 3 is attached in the direction of the arrow P1, that is, in such a manner that a biasing force is applied in the direction. ! The proximal end of the second terminal 6, which is made of bimetal with an H cross section and is drilled inside and outside the case, is caulked and fixed to the tip of the second terminal 6 with a rivet 7, and the fixed contact 8 is fixed to the movable contact 3 on the free end side. It is attached by caulking to the part facing the. Does 9 protrude inside and outside the case? A fixed contact 30 is fixed to the free end of the third terminal. In such a device, in the normal state, the contact 3 is in pressure contact with the contact 8 side at the first stable point (solid line position in Figure 1) due to the biasing force of the arcuate spring 23, and as will be described later, overcurrent is generated. The bimetal is deformed by the fluid force, and when the leaf spring part vr2 is reversed and is at the second stable point (the two-point line position in Figure 1), it presses against the contact 3 toward the fixed contact 30 side. .

Note that the third terminal 9 and the fixed contact 30 may be removed if they are unnecessary. Reference numeral 18 denotes a presser made of an insulating material such as m-type resin, and the bridging piece 21 of the plate spring member 2 is hooked to a cutout groove 111A formed in the lower middle part of the presser to support it inside the case. The upper end of the child faces the upper end surface of the case 1 through the opening IA on the upper surface. If necessary, a handle portion 18B is formed at the upper end of the pusher 18, and the handle portion 11mB is protruded from the upper end surface of the case 1, and the plate spring member 2 is moved from one of the stable points by a push/pull operation from outside the case. The other stable point +c9 may be determined.

19Fi is made of paris with a corrugated portion formed on the lower surface thereof, and is integrally formed on the insulating base 10 for the purpose of insulating between the leaf spring member 2 and the bimetal 5.

Next, the operation will be explained. In the normal state, the switch according to the present invention is arranged so that the slope spring portion vf2 is at the solid line position (first stable point) in Fig. g1. In this position, as mentioned earlier, the elastic force of the arcuate spring 23 is as indicated by the arrow pt.
Therefore, a downward pressing force M1 is applied to the contact point 3 as shown in FIG. Next, when an overcurrent flows between the terminals 4 and 6 due to an accident or the like, the bimetal 5 gradually deforms upward from the state shown in Fig. A pressing force in the direction is applied to the contact 8, and the leaf spring member 2 is displaced upward while maintaining the fk state in which a force is applied in the direction of mutual pressure between the contacts 3 and 8. When the leaf spring member 2 passes the position shown in FIG. 3 (2), the arcuate spring 23 is instantaneously reversed and the leaf spring member 2 is in the state shown in FIG. The state will be as shown by the yelp line (second stable point).

At this time, the contact 3 breaks contact with the contact 8 to protect the faulty circuit, and on the other hand, contacts the contact 30 side with the upward pressing force M1. Next, the cause of the accident due to overcurrent is removed,
To return to the original state, press the tip of the presser 18 protruding from the top of the case, and return the leaf spring member 2 to the first stable point via the bridging piece 21 hooked on the groove 18A. .

Next, a procedure for assembling the small switch according to the present invention will be explained. FIG. 4 is a front view showing the relationship between the terminal and the insulating base during insert molding, and FIG. 5 is a front view showing the cutting and bending of each terminal after insert molding. According to this invention, first, punching dies 51 of a fixed shape are continuously punched out from a band-shaped conductive member 50 by pressing, and the insulating base 10 is integrally molded at a predetermined position on the body of each cutting die 51 by insert molding. do. The integrally molded products thus obtained are shown in FIG.
After cutting at the portions to form independent unit bases, a predetermined bending process is performed at each of the B1-B1 to Ba-B4 portions to form a top-position base as shown in FIG. After that, bimetal 5 with rivet 7
is fixed in the through hole 611C of the terminal 6, the leaf spring member 3 is fitted and locked in the grooves 41 and 42 of the terminal 4, and the contact 30 is caulked into the through hole 91 of the terminal 9. After this is hooked onto the temporary spring member 3, the case 1 is closed to complete the small switch of the present invention.

(g) Effects of the invention: This invention is configured so that the deformation direction of the bimetal due to overcurrent acts in the direction in which pressure contact force is applied to both the movable and fixed contacts. It becomes possible to stably maintain the contact state between the contacts without weakening the contact pressure between them, and the operational reliability of the switch can be improved. In addition, a configuration is adopted in which an arcuate spring is formed by punching the leaf spring member itself, and the sieving force of the arcuate spring is applied between both contact points.
This has the effect of reducing the number of component parts and contributing to lower product costs.

In addition, this invention allows each terminal to be integrally attached to the insulating base by insert molding, and all that is required is to attach predetermined parts to each terminal by caulking or fitting.
Automatic assembly of this type of device is facilitated, and costs can be reduced through metering.

[Brief explanation of the drawing]

Fig. 1 is a front view of a small switch according to an embodiment of the present invention, with the front cover removed, Fig. 2 is a plan view with the top cover removed, and Fig. 3 is a plate. An explanatory diagram of the operation of the spring member, Fig. 4 is a front view showing the relationship between the terminal and the insulating base during insert molding, Fig. 5 is a front view showing the cutting and bending of each terminal after insert molding, FIG. 6 is a longitudinal sectional front view of a conventional small switch. 1... Case, 2... Leaf spring member, 23...
...Archive spring, 3...Movable contact, 4...
・First terminal, 41゜42...-F[,5...Bimetal, 6...Italy second terminal, 8,30...Fixed contact, 9...Third @ Child, 10... Insulating base, 18-... Presser.

Claims (4)

[Claims] (1) First and second parts formed by insert molding on an insulating base
A terminal, a plate spring member formed by pulling out and raising an arcuate spring approximately in the center and having a movable contact attached to the tip of one side; A bimetal is attached to an upper side of the base of the second terminal so that the biasing force of the arcuate spring acts in the attachment direction of the movable contact in the engagement groove formed in the portion, and a bimetal is attached to the upper side of the base of the second terminal. A fixed contact is attached to the free end side of the bimetal so as to press against the movable contact, and the deformation force of the bimetal that occurs when an overcurrent flows between the first and second terminals is used to A small switch characterized in that the movable and fixed contacts are separated by reversing the leaf spring member. (2) The small switch according to claim 1, wherein the deforming force of the bimetal due to overcurrent is applied in the pressure contact direction between the movable and fixed contacts. (3) The small switch according to claim 1, wherein the arcuate spring is integrally formed with a plate spring member. (4) A patent characterized in that a third terminal is provided, a fixed contact is attached to the terminal, and a movable contact attached to the leaf spring member is held in pressure contact with the fixed contact when the leaf spring member is in an inverted state. A small switch according to claim 1.