JPS6220969Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a semi-fixed variable resistor used in small consumer appliances and the like.

Examples of conventional variable resistors include those shown in FIGS. 1 and 2.

Reference numeral 1 in both figures represents an insulating substrate, and a resistor layer 2 made of a carbon film or the like is formed on the surface of this insulating substrate 1.

The resistor layer 2 is formed into a substantially half-arc shape when viewed from above, and both ends thereof are connected to terminals 4 through a conductor layer 3 mainly composed of silver. The terminals 4, 4 are each fixed to the insulating substrate 1 by a mounting portion 4a.

Further, on the side of the insulating substrate 1 on which the resistor layer 2 is formed, a substantially circular slider 5 with a diameter of about several mm is arranged, and a cylindrical insulating spacer is placed between the slider 5 and the insulating substrate 1. 6 is interposed.

An arc-shaped groove 5a is bored in the slider 5, and the groove 5a is divided into a semi-annular arm 5b and a slider base 5c. and arm 5b
A contact 5 is placed approximately in the center of the resistor layer 2.
d is provided protrudingly. The arm 5b is slightly bent toward the insulating substrate 1 at a portion near the end of the groove 5a. Further, a rectangular hole 5e is bored approximately at the center of the slider base 5c.

On the other hand, on the back side of the insulating substrate 1, an intermediate terminal connecting portion 7a is provided which is connected to the intermediate terminal 7, and the intermediate terminal 7 and the intermediate terminal connecting portion 7a are fixed to the insulating substrate 1 by a mounting portion 7b. . Further, a metal mounting plate 8 is opposed to the intermediate terminal connecting portion 7a, and a cylindrical shaft portion 8a cut and raised in the metal mounting plate 8 is connected to the intermediate terminal connecting portion 7a, the insulating substrate 1, and the insulating spacer 6. It is commonly penetrated in a loosely fitted state. Locking tongues 8b, 8b provided at the end of the cylindrical shaft portion 8a are fitted into the rectangular hole 5e and bent, and caulked at both longitudinal edges of the rectangular hole 5e. By this caulking, the slider 5 and the metal mounting plate 8 are integrally attached to each other, and the slider 5 is made rotatable with respect to the insulating substrate 1 and is attached via the metal mounting plate 8. It is electrically connected to the intermediate terminal 7. Further, when the slider 5 and the metal mounting plate 8 are integrally attached as described above, the insulating spacer 6 allows the slider 5 to
is prevented from coming into contact with the resistor layer 2 at a location other than the contactor 5d, and the pressing force of the contactor 5d against the resistor layer 2 is appropriately adjusted.

By inserting the tip of a flathead screwdriver into the rectangular hole 5e and rotating it, the resistance between the intermediate terminal 7 and one of the terminals 4 is adjusted to a desired resistance value.

However, in such a conventional variable resistor, the slider base 5c has a relatively small size.
Since a rectangular hole was drilled in the hole and this hole was used for rotational operation, only a flathead screwdriver could be used, which combined with the instability of the drive operation making accurate fine adjustment difficult. Since the slider is only as thick as the slider, there is a problem in that the rotational force during operation is concentrated in one part, and the rectangular hole 5e is seized and the slider is deformed. In addition, conventional variable resistors require an insulating spacer made of a separate material between the insulating substrate and the slider, which makes assembly work quite troublesome and increases the number of parts. There was a problem in that parts management became more troublesome. Furthermore, the conventional variable resistor has a problem in that the so-called live part consisting of the slider and the resistor layer is directly exposed to the outside, so that the live part is easily damaged during handling.

This idea was created by focusing on these conventional problems, and it is a resin rotating body consisting of a cylindrical insulating spacer part and an operating part with a cross groove for inserting a screwdriver. A part of the slider is buried to hold it together, and the cross groove penetrates the operating part and reaches the rectangular hole, and a first rectangular groove that communicates with the cylindrical shaft part is perpendicular to the first rectangular groove and reaches the slider. The present invention aims to solve the above-mentioned problems by forming a second rectangular groove with a bottom and covering the slider substantially entirely with the operating section.

This invention will be explained below based on the drawings.

In each of the figures following FIG. 3, the same or equivalent members or parts as in FIGS. 1 and 2 are designated by the same reference numerals and redundant explanations will be omitted.

3 to 6 show an embodiment of this invention.

First, to explain the configuration, in this idea,
Through-holes 5f and 5g facing each other with the rectangular hole 5e in between are formed in the slider 5, which is approximately disk-shaped and has a contact 5d formed therein and a rectangular hole 5e formed approximately in the center thereof. , the rotating body A integrally molded with resin and the slider 5 is continuous through these through holes 5f and 5g.

This rotating body A has a cylindrical insulating spacer portion 6
and an operating section 9 located on the opposite side of the insulating spacer section 6 with the slider 5 in between, and in which a cross groove 11 for inserting a screwdriver is formed. Further, the rotating body A is in contact with one surface of the insulating substrate 1 with the insulating spacer portion 6 facing the insulating substrate 1 side, and is engaged with a cylindrical shaft portion 8a cut and raised in a metal mounting plate 8 attached to the other surface. It is rotatably attached to the insulating substrate 1. Note that the operating portion 9 is formed in a shape that substantially entirely covers the slider 5, and is configured to protect the slider 5 from external impact.

The above-mentioned cross groove 11 is perpendicular to the first rectangular groove 11a that passes through the operating part 9 from above in FIG. A second rectangular groove 1 is provided with a bottom portion 9a that does not reach the slider 5 from the upper side in FIG.
1b.

The slider 5 has both longitudinal edges of the rectangular hole 5e exposed upward in FIG. 6 from the first rectangular groove 11a. Locking tongues 8b, 8b formed at the tip of the cylindrical shaft portion 8a and fitted into the rectangular hole 5e are bent and caulked into engagement with these both edges.

Next, an example of a method for integrally forming the insulating spacer section 6 and the operating section 9 on the slider 5 in advance by a resin molding method will be described with reference to FIG. 7 as well.

First, as shown in FIG. 7, from the steel strip 12 to the slider 5
is formed by punching. Although only one slider 5 is shown in FIG. 7, a plurality of sliders 5 are punched out successively in the longitudinal direction of the steel strip 12 (left-right direction in FIG. 7). During this punching, grooves 5a, rectangular holes 5e,
The through holes 5f and 5g are also bored at the same time.

Next, with the plurality of sliders 5 still connected, a mold or masking of a predetermined shape coated with a mold release agent on both sides of the slider 5 is held in contact with, for example, one of the through-holes. Inject thermoplastic resin liquid such as polyacetal through an injection port corresponding to 5 g. The thermoplastic resin liquid first fills the mold for the insulating spacer portion 6, then flows into the other side of the slider 5 through the other through hole 5f, and then flows into the mold for the operating portion 9. After cooling and solidifying, the mold or masking is removed to complete the rotating body A that integrally holds the slider 5. Note that the tapered portion indicated by the reference numeral 9b in FIGS. 4 and 6 is formed for convenience of punching from a mold, etc., and can be formed into any shape as needed. It is not an essential formation site for the variable resistor. Next, after the above formation, each slider 5 is separated.

Next, the action will be explained.

When the tip of a Phillips screwdriver is inserted into the cross groove 11 and the operating section 9 is rotated, the slider 5 and the insulating spacer section 6 are rotated together with this. A desired resistance value corresponding to the operational rotation position of the contactor 5d appears between the intermediate terminal 7 and the terminal 4.

At this time, the rotation of the slider 5 is adjusted by means of the cross groove 11, which is set larger than the rectangular hole 5e of the slider 5 that was conventionally used for adjustment, so a stable rotational state can be obtained and accurate rotation can be achieved. Fine adjustments are made. Further, the tip of the Phillips screwdriver inserted into the cross groove 11 stops when it hits at least the bottom 9a of the second rectangular groove 11b, and does not penetrate any further.

If you don't have a Phillips screwdriver handy, you can also use a flat head screwdriver. At this time, if a flathead screwdriver is inserted into the bottomed second rectangular groove 11b and the operating section is rotated, the tip of the flathead screwdriver stops when it hits the bottom part 9a, and does not penetrate any further.

Furthermore, in the variable resistor of this invention, the cylindrical shaft portion 8a
The rotation can be adjusted from the back with a flat head screwdriver. At this time, even if the tip of the flathead screwdriver hits the slider 5, the bottom portion 9a that is in close contact with the back surface of the slider 5 will receive the impact force. Further, during the rotation operation, the tip of the flathead screwdriver rotates the rotating body A by engaging with a surface parallel to the driver insertion direction in the bottom portion 9a instead of the rectangular hole 5e.

As explained above, according to this invention, the slider is partially embedded and integrated into the rotating body consisting of the operation part and the insulating spacer part, so that it is classified as a small component among all the components in the conventional example. The number of parts is reduced by one insulating spacer, which simplifies assembly work and reduces the burden of parts management.

In addition, the operation part has a cross groove consisting of two rectangular holes, one with a bottom and the other with a tube through, allowing for stable drive operation and the ability to use a Phillips screwdriver, making it easy to make accurate fine adjustments. In addition to the effects that can be achieved, there are also
The tip of either flathead screwdriver stops when it hits the bottom of the second rectangular groove and does not penetrate any further, so there is no chance that the tip of the screwdriver will hit the slider 5, which is a conductive part, and damage it. There is no deterioration in electrical performance as a variable resistor.

Next, with the variable resistor of this invention, it is possible to adjust the rotation with a flathead screwdriver from the back through the cylindrical shaft, and in this case, the tip of the flathead screwdriver engages with the surface parallel to the screwdriver insertion direction at the bottom Since the rotary body is rotated, the slider is not deformed by jamming the rectangular hole.

Furthermore, since the operation section is shaped to cover almost the entire slider, the so-called live parts such as the resistor layer and slider can be protected from external shocks during assembly and transportation, and are particularly sensitive to shocks. Contacts that are susceptible to damage can be effectively protected.

[Brief explanation of the drawing]

Figure 1 is a side view showing a conventional variable resistor, Figure 2 is a side view showing a conventional variable resistor.
3 is a side view showing an embodiment of the variable resistor according to the invention; FIG. 4 is a plan view of the variable resistor mentioned above; FIG. The figure is a bottom view showing the integrated molded part of the slider and rotating body removed from Figure 3, Figure 6 is a sectional view taken along the line - - in Figure 5, and Figure 7 is the fabrication of the slider in Figure 3. FIG. DESCRIPTION OF SYMBOLS 1... Insulating substrate, 2... Resistor layer, 5... Slider, 5d... Contact, 5e... Rectangular hole, 6... Insulating spacer portion, 8... Metal mounting plate, 8a... Cylindrical Shaft part, 9... Operating part, 9a... Bottom part, 11... Cross groove, 11a... First rectangular groove, 11b... Second rectangular groove, A... Rotating body.

Claims (1)

[Claims for Utility Model Registration] An insulating substrate having an arc-shaped resistor layer formed on one surface, a contact that comes into elastic contact with the resistor layer, and a substantially rectangular hole bored approximately in the center thereof. A disc-shaped slider, and a cylindrical insulating spacer portion that holds the slider integrally by partially burying the slider and separates the insulating substrate and the slider, sandwiching the slider. an operating section formed on the opposite side of the insulating spacer section and provided with a cross groove for inserting a screwdriver; A cylindrical shaft portion is cut and raised to engage a rectangular hole drilled in the insulating substrate, and a metal mounting plate is attached to the other surface of the insulating substrate to rotate integrally with the rotating body, and the cross groove is formed in the cross groove. Consisting of a first rectangular groove that penetrates the operating portion and reaches the rectangular hole and communicates with the inside of the cylindrical shaft portion, and a second rectangular groove with a bottom that is orthogonal to the first rectangular groove and does not reach the slider. A variable resistor, wherein the operating portion has a shape that substantially entirely covers the slider.