JPH037002Y2 - - Google Patents

Description

[Detailed description of the invention] -Field of industrial application- This invention relates to a mounting structure for a return spring in a spring return switch. A spring return switch uses a coiled spring to return the switch when the switch operating force is released. For example, in the case of a spring return switch as shown in Fig. 3, when the operating force P is applied, the movable piece 6 rotates counterclockwise around the pivot point 7 to operate the switch, and when the operating force P is released, the switch moves. The switch is returned to its original position by a spring force S acting on the piece 6.

Here, in detail about the changeover switch shown in FIG. 3, 1 is a fixed piece made of insulating material, 2,
3 and 4 are leaf springs whose base ends are fixed to the fixing piece 1;
a, 3a, 3b, and 4a are contacts provided on each leaf spring 2, 3, and 4; 5 is a stopper that is suspended horizontally on the fixed piece 1 to regulate the return position of the leaf spring 3; and 6 is a stopper provided on the fixed piece 1. A movable piece made of an insulating material is pivotally attached to the movable piece, 7 is its pivot point, and 8 and 9 are protrusions provided on the movable piece 6 for operating the leaf springs 2 and 4.

By the way, the changeover switch shown in FIG.
When the height of the protrusion 8 is increased, as the movable piece 6 rotates, the protrusion 8 first comes into contact with the leaf spring 2 and When the movable piece 6 is bent to bring the contacts 2a and 3a into contact, and the movable piece 6 is further rotated, the protrusion 9 comes into contact with the leaf spring 4 and bends it, bringing the contacts 3b and 4 into contact.
Separate from a. That is, it operates as a continuous contact. In addition, when the height of the protrusion 9 is increased, as the movable piece 6 rotates, the protrusion 9 first contacts the leaf spring 4 and bends it, separating the contact points 3b and 4a, and further movable the protrusion 9. When the piece 6 rotates, the protrusion 8 comes into contact with the leaf spring 2 and bends it, bringing the contacts 2a and 3a into contact. That is, it operates as a transfer contact.

-Prior Art- The conventional mounting structure for the return spring 12 in such a spring return switch is as shown in FIG. 4 or 5. The one shown in FIG. 4 uses a tension spring 12a, and the one shown in FIG. 5 uses a compression spring 12b to apply a return moment to the movable piece 6. Note that in the case shown in FIG. 5 using a compression spring, when the movable piece 6 returns to its original position due to the support structure at both ends of the spring, the spring 12b
is often bent into an S-shape.

The return force S in such a conventional switch
The relationship between (S' in FIG. 6) and the stroke of the movable piece is shown in FIG. Here, S ₁ is the return force caused by the spring force of the leaf springs 2, 3, and 4,
Points A and B are the points at which the protrusion 8 or 9 and the leaf spring 2 or 4 come into contact. S ₂ ′ is the return spring 12a,
With the return force based on the urging force of spring 12b, spring 12a,
The tensile or compressive force of 12b is T, the length of the normal line from the pivot point 7 to the axis of the springs 12a, 12b,
That is, the length of the arm of the return moment is L, the length of the normal line from the pivot point 7 to the line of action of the operating force P, that is, the length of the arm of the operating moment is M, and the spring due to the rotation of the movable piece 6 is The change in the biasing force of 12a and 12b is ΔT,
If the change in arm length L of the return moment is ΔL, it is given by S ₂ ′=(T+ΔT)*(L−ΔL)/M. F is a frictional load generated when the movable piece 6 rotates. Therefore, the total return force S′ is S ₁ +
S ₂ ', and the curve of S' must be above the friction load curve F. Furthermore, the operating force curve P for such a switch must be above the curve Q, which is the sum of the return force S' and the frictional load F.

-Problems to be Solved by the Invention- Nowadays, with the miniaturization and weight reduction of various devices, there has been a demand for reducing the operating force of switches. For example, when it comes to a switch on a telephone handset, the weight of the handset is reduced, which reduces the operating force needed to operate the switch.

As is clear from Fig. 6, in order to ensure that the switch operates even when the operating force P is small, it is necessary to make the curve of the return force S' flat and to reduce the frictional load F. It is. Since the return force S1 of the leaf springs 2, 3, and ₄ inevitably curves upward to the right, in order to make the total return force S' flat, the return force of the return spring 12 must be increased.
The curve of S ₂ ′ must have a downward-sloping characteristic. As mentioned above, S ₂ ′=(T+ΔT)*
Since (L-ΔL)/M, it is possible to make the curve of the return force S ₂ ' downward to the right by decreasing ΔT and increasing ΔL. In fact, in the past, attempts were made to reduce the operating force of the switch based on such a concept, but in order to reduce ΔT, it was necessary to increase the length of the return spring 12, and when trying to increase ΔL, the return It is necessary to separate the support points 10 and 11 of the spring 12 from the pivot point 7 of the movable piece, which causes the switch to become larger. This results in an increase in the force P, and the movable piece 6
As it rotates, T increases and L decreases, so the curve of the friction load F also has an upward-sloping characteristic, making it impossible to sufficiently meet the demand for reducing the operating force P.

This invention solves the above problems and increases the operating force P.
The purpose of this invention is to provide a structure that allows the switch to be made smaller and smaller in size.

- Means for solving the problems - The present invention solves the above problems by using a compression spring as the return spring of the movable piece and making the characteristics of this compression spring reverse. The switch has a return spring 1 of a movable piece 6 that operates a contact point.
2, a compression spring is used as the movable piece 6 so that the compression spring is in a straight line when the movable piece 6 is in the return state and is in a bent state when the switch is operated and the movable piece 6 rotates. and fixed piece 1
It is mounted between. In this case, the compression spring 12
is used in the buckling region so that the spring 12 is bent by buckling when the movable piece 6 is rotated. That is, both ends of the compression spring 12 are held by the movable piece 6 and the fixed piece 1 so as not to be tiltable, and the spring 12 is mounted so that both ends are positioned on a straight line when the switch is returned. The end of one movable side is tilted by the swinging of the movable piece 6,
Combined with the compressive force applied to the spring 12, the spring 12 is buckled into a bent state.

- Effect - In this case, when the compression spring 12 is bent, its biasing force in the axial direction is reduced, and has the opposite characteristic, that is, when the spring is compressed, its biasing force is reduced. is given. As a result, the curve S ₂ of the return force by the return spring 12 becomes the second
As shown in the figure, it is downward to the right, and the leaf springs 2, 3,
Total return force S including urging force S of 4 and ₁
curve can be flattened. Also,
Since the characteristics of the return force S are not changed by increasing ΔL, the positions of the support points 10 and 11 of the return spring 12 can be freely determined, and these are placed near the pivot point 7. This makes it possible to downsize the switch.

-Embodiment- An embodiment of the present invention is shown in Fig. 1, in which figure a shows the state in which the switch has returned, and figure b shows the state in which the switch has been operated. The difference between the switch according to the present invention shown in FIG. 1 and the conventional switch using a compression spring shown in FIG. 5 is that in the switch according to the present invention, the compression spring 12 is When the switch is operated, the switch is mounted in a straight line and becomes bent when the switch is operated.
In the conventional device, the compression spring 12b is mounted in a bent state when the switch is in the return state, and becomes straight when the switch is operated. Further, in the conventional type, the compression spring latching members 10 and 11 are both provided at positions separated from the pivot point of the movable piece, whereas in the present invention, one of the latching members 11 is provided at a position close to the pivot point 7. Therefore, in the present invention, even when the movable piece 6 rotates, the above-described change in L hardly occurs.

The relationship between the stroke and force of the switch shown in FIG. 1 is shown in FIG. The compression spring 12 is
When the movable piece 6 is pressed down, it is bent into a dogleg shape due to the compressive force, and this bending causes the spring 1 to
The axial biasing force of No. 2 decreases. This reduction in biasing force appears particularly large when the compression spring 12 is used in a buckling region. Therefore, the return force S ₂ due to the compression spring 12 has an inverse characteristic of downward slope to the right, and the flat spring 2,
The total restoring force S, including the restoring forces _S1 due to 3 and 4, becomes flat. In addition, the curve of the return force S becomes flat, and there is no need to change the moment arm length L during the rotation of the movable piece 6, making it possible to make the switch smaller and lighter. Since the biasing force can also be reduced, the frictional load F can be reduced, and thereby the return force S can be further reduced.
The friction load F and the return force S, and therefore the operating force P, can be significantly reduced compared to the conventional one.

-Effects- As described above, the structure of the present invention has the advantage that the operating force of the spring return switch can be significantly reduced compared to conventional ones, and the switch can also be made smaller and lighter. can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the switch of the present invention, in which a shows the state when the switch is restored and b shows the state when it is operated. FIG. 2 is a diagram showing the relationship between the operating stroke, operating force, and return force in the switch shown in FIG. 1. Fig. 3 shows an example of the internal structure of a spring return switch, Figs. 4 and 5 show a conventional return spring mounting structure, and Fig. 6 shows the operating stroke and operating force of a conventional switch. FIG. In the figure, 1 is a fixed piece, 2, 3, 4 are leaf springs, 2
a, 3a, 3b, 4a are contacts, 5 is a stopper, 6
is a movable piece, 7 is a pivot point, 8, 9 are protrusions, 10, 1
1 is the latch member, 12 is the return spring, P is the operating force, S ₁
is the return force due to the biasing force of the leaf spring, S ₂ , S ₂ ′ is the return force due to the biasing force of the return spring, S is the total return force that is the sum of S ₁ , S′ and S ₂ or S ₂ ′, F is the frictional load during switch operation.

Claims (1)

[Scope of claim for utility model registration] The movable piece 6 that operates the contacts of the switch is the fixed piece 1.
In a switch which is pivotably mounted on a switch and is operated to swing, and in which a compression spring 12 is used as a return spring for the movable piece, the compression spring is held at both ends by the movable piece 6 and the fixed piece 1 so as not to tilt. The return spring in a spring return switch is characterized in that when the switch is operated, the return spring is buckled and bent due to the tilting of one end of the movable side when the switch is operated. Mounting structure.