JPH10172814A - Slide type variable resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a product of superior dustproof performance whose operational touch is not deteriorated even after using over a long time, in a dustproof type mainly used for an audio mixer, etc. SOLUTION: Both end parts of a root of a plate-like operating lever 12 passing through a slit 8A of a dustproof sheet 8, which is stuck on the top surface of a cover 1 for avoiding dust, are made protrusions 13 formed of a resin integrated with a slider 11 while having a same thickness as the operating lever 12, and its end surface is made round or chamfered shape, thereby reducing the number of times of operation and improving operational touch even after placed in a high temperature atmosphere over a long time. Thus a slide type variable resistor of superior dustproof performance is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dustproof slide variable resistor mainly used in audio mixers and the like.

[0002]

2. Description of the Related Art A slide-type variable resistor used in an audio mixer or the like performs quick and delicate adjustments, so that light and smooth sliding is necessary, and a sliding contact pressure is set to be small. When dust enters through the operation lever opening, sliding noise easily occurs, and a dustproof structure for preventing dust from entering is particularly important.

FIG. 6 is a perspective view showing the appearance of a conventional dustproof slide variable resistor, and FIG. 7 is a sectional view of the variable resistor. In FIG. , A narrow opening 1A along the longitudinal direction on the upper surface
have.

[0004] Reference numeral 2 denotes a resistive substrate made of an insulating material disposed so as to cover an open portion on the lower surface of the cover 1, and has an elongated resistive element layer 3 inside the cover 1 on the upper surface thereof.

Reference numeral 4 denotes a slider made of a resin such as polyacetal resin housed in the cover 1, and an operation lever 5 made of a metal plate fixed on the upper portion thereof by insert molding has a narrow opening of the cover 1. 1A, a sliding contact 6 mounted on the lower surface is in elastic contact with the resistive element layer 3 of the resistive substrate 2 at a predetermined pressure, and the slider 4 is moved through the operating lever 5 in the longitudinal direction of the cover 1. As a result, the sliding contact 6 linearly slides on the resistance element layer 3 to change the resistance value.

Further, as shown in the top view of FIG. 8, a dustproof sheet 8 made of a flexible insulating material such as polyethylene having a slit 8A in the center is provided on the outside of the upper surface of the cover 1 with a narrow opening. The slit 8A is attached so as to close the portion 1A so as to coincide with the center line of the narrow opening 1A. The operation lever 5 penetrates through the slit 8A of the dustproof sheet 8 and projects upward. I have.

Therefore, when the operating lever 5 is moved linearly, the front and rear ends 5A of the operating lever 5 move while pushing and opening the slits 8A of the dustproof sheet 8, and the portion through which the operating lever 5 does not penetrate is flexible. The gap is closed by the property, so that the intrusion of dust into the resistance element layer 3 can be prevented.

[0008]

However, in the above-described conventional dust-proof slide type variable resistor, the end 5A of the operating lever 5 penetrating through the slit 8A of the dust-proof sheet 8.
8A when it moves while pushing and opening slit 8A
When the number of operations increases, the contact feeling may become poor.

If the slide type variable resistor is left standing for a long time in a high-temperature atmosphere in a stationary state, the end of the operation lever 5 is inserted into the portion of the slit 8A of the dustproof sheet 8 made of polyethylene or the like through which the operation lever 5 penetrates. Marks of the corners of the portion 5A were attached, and a light sensation was sometimes felt during operation.

Further, as shown in the top view of FIG. 8, the slit 8A of the dust-proof sheet 8 has an intermediate portion 8B between a portion opened and closed for the operation lever 5 to penetrate and a portion closed.
Is a triangular gap, and there is also a problem that a small amount of dust enters the inside of the slide-type variable resistor from this portion.

SUMMARY OF THE INVENTION An object of the present invention is to provide a slide type variable resistor which has no deterioration in operation feeling even when used for a long time and has excellent dustproof performance. Is what you do.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a slide type variable resistor according to the present invention is provided with a plate-shaped operating lever at the base of a plate-like operating lever penetrating through a slit of a dustproof sheet fixed to the upper surface of a cover for dustproofing. Both end portions are made of resin integral with the slider and formed as protrusions having the same thickness as the operation lever, and the end surfaces thereof have a circular or chamfered shape.

According to the present invention, it is possible to realize a slide type variable resistor having excellent dustproof performance without deterioration of operation feeling even after the number of operations is increased or after being placed in a high-temperature atmosphere for a long time.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to an elongated box-shaped cover having an open bottom surface having a narrow opening along the longitudinal direction on the upper surface, and an open surface of the lower surface of the cover. A resistive substrate coupled so as to close, a resin slider slidably accommodated in the cover having a sliding contact on its lower surface which resiliently contacts a resistive element layer formed on the resistive substrate, A dustproof sheet made of a flexible resin fixed to the upper surface of the cover to have a slit corresponding to the center position of the narrow opening of the cover so as to cover the narrow opening, and sandwiched between the slits of the dustproof sheet; A vertically long plate-like operation lever integrally provided at the top of the slider so as to penetrate through the dustproof sheet and protrude upward, and sliders at both ends of a portion sandwiched by the dustproof sheet at the root of the operation lever Formed from one piece of resin The end of the control lever is made of a circular or chamfered protruding part. The contact surface of the slit is not roughened, and the operation feeling is not degraded due to the marks of the corners of the operation lever.In addition, the part between the part where the operation lever of the slit of the dustproof sheet is pushed open and the part where it is closed Has the effect that the dust clearance can be increased.

According to a second aspect of the present invention, in the first aspect of the present invention, the operation lever is formed by insert-molding a metal plate into a resin forming the slider, and the strength is reduced even when the thickness is small. This has the effect that a large operation lever can be provided.

According to a third aspect of the present invention, in accordance with the second aspect of the present invention, cut portions are provided on both sides of a portion between the dustproof sheet at the base of the operating lever made of a metal plate, and a resin is projected outside the cut portion. Part is formed integrally, without increasing the amount of protrusion of the protrusion from the end of the operation lever,
This has the effect that the resin protrusion can be stabilized in strength.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the operation lever is formed of resin integrally with the slider, so that the slider with the operation lever can be formed at low cost. Having.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the projecting portions formed at both ends of the portion between the dustproof sheet at the root of the operation lever are provided.
The lower part is tapered so that the lower part is wider than the upper part.When the operating lever is moved linearly, the front and rear ends of the operating lever open so as to push up the slit of the dustproof sheet, so there is less resistance when pushing open. In addition to the smooth operation, there is an effect that almost no gap is formed between a portion where the operation lever of the slit of the dustproof sheet is pushed open and a portion where the operation lever is closed.

According to a sixth aspect of the present invention, the slider according to any one of the first to fifth aspects, wherein the slider is formed of a polyacetal resin, and the dust-proof sheet is formed of polyethylene terephthalate. Even when used for a long time, the operation feeling is stable, and particularly, there is an effect that deterioration of the operation feeling is small when the device is placed in a high-temperature atmosphere.

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. The same components as those described in the section of the related art are denoted by the same reference numerals, and detailed description thereof will be omitted.

(Embodiment 1) FIG. 1 is a sectional view of a slide type variable resistor according to a first embodiment of the present invention.
In FIG. 1, reference numeral 1 denotes a box-shaped cover made of a metal plate having a narrow opening 1A on the upper surface, and an open portion on the lower surface thereof is closed by a resistance substrate 2 having a resistance element layer 3 on the upper surface.
An operation lever 12 made of a metal plate is fixed by insert molding to an upper portion of a slider 11 made of resin accommodated therein, and protrudes upward from a narrow opening 1A of the cover 1, and is mounted on a lower surface of the slider 11. The moving contact 6 is the resistance element layer 3
When the slider 11 linearly moves in the longitudinal direction of the cover 1 via the operation lever 12, the sliding contact 6 linearly slides on the resistance element layer 3 to change the resistance value. Slit 8 in the center outside the upper surface of 1
A structure in which a dust-proof sheet 8 made of a flexible insulating material having an A is attached so as to cover the narrow opening 1A, and the operation lever 12 projects upward through the slit 8A, as described above. It is the same as the technology.

However, at both ends of the root of the operation lever 12 sandwiched between the slits 8A of the dustproof sheet 8 on the upper surface of the cover 1, the slider 11 has the same thickness as the operation lever 12.
Protruding portion 13 formed of a resin integral with
Is provided.

The protrusion 13 is provided integrally with a portion for filling the resin into a cut portion 12A provided on an end face of the operation lever 12 for preventing the operation lever 12 from coming off. The width of the resin portion is increased without increasing the amount of protrusion of the protrusion 13 from the portion, whereby the protrusion 13 is stable in strength.

Therefore, as shown in the top view of FIG.
When the operation lever 12 is moved linearly, the protrusion 13
Since the circular end face of the slide type variable resistor moves while pushing and opening the slit 8A of the dustproof sheet 8, the contact surface of the slit 8A does not become rough, and even if the number of operations increases, the operation feeling of the present slide type variable resistor hardly changes. can do.

Even if the present slide type variable resistor is placed in a high-temperature atmosphere for a long time, there is no sharp portion at the end of the operation lever 12 penetrating the slit 8A of the dustproof sheet 8, so that the slit 8A There is no trace.

Further, as shown in the top view of FIG. 2, an intermediate portion 8 between a portion opened and closed for the operation lever 12 of the slit 8A of the dustproof sheet 8 to penetrate therethrough.
A considerable portion of the triangular gap B is also closed and narrowed by the circular end face of the projection 13, so that dust hardly enters the inside of the slide-type variable resistor from this portion. .

In the above description, the case where the end faces of the protrusions 13 provided at both ends of the root of the operation lever 12 sandwiched between the slits 8A of the dustproof sheet 8 are circular has been described. As shown in the partial top view, it is a matter of course that the protrusion 13A may have a chamfered shape.

(Embodiment 2) FIG. 4 is a sectional view of a main part of a slide type variable resistor according to a second embodiment of the present invention. In FIG. 4, reference numeral 14 denotes a slider. The lever 14A and the protrusion 14B at the base thereof are integrally formed of resin.

The end surfaces of the protrusions 14B at both ends of the operation lever portion 14A at the both ends of the operation lever portion 14A sandwiched between the slits 8A of the dustproof sheet 8 have a circular or chamfered shape as in the first embodiment.

Therefore, as in the case of the first embodiment, even if the number of operations is increased, or even if the operation lever portion 14A is placed in a high-temperature atmosphere for a long time, the operation lever portion 14A roughens the contact surface of the slit 8A of the dustproof sheet 8, There is no trace of the end of the operation lever portion 14A and the operation feeling is not deteriorated.
The operation lever 14A of the slit 8A of the dustproof sheet 8
Part 8B between the part that is pushed open and the part that is closed
The same applies to the fact that a considerable part of the triangular gap is closed.

In the case of the slide type variable resistor according to the present embodiment, the slider 14 and the operation lever 14A and the protrusion 14B can be formed at a low cost because they are integrally formed of resin. Is also made of resin, so that compared to the first embodiment,
A long operation lever is disadvantageous in strength, but a short operation lever can be used without any problem.

(Embodiment 3) FIG. 5 is a sectional view of a main part of a slide type variable resistor according to a third embodiment of the present invention.
A protrusion 15A made of resin integral with the slider 15 is provided at both ends of a root portion of the operation lever 12 sandwiched between the slits 8A. The protrusion 15A has the same thickness as the operation lever 12 and has a circular end face. It is said that the first embodiment
In this case, the width is tapered so that the lower part is wider than the upper part.

Thus, when the operation lever 12 is moved linearly, the protrusions 15A at the front and rear ends of the operation lever 12 are opened so as to push up the slit 8A of the dustproof sheet 8, so that the resistance at the time of pushing open is small. A smooth operation can be performed, and a gap between a portion where the operation lever 12 of the slit 8A of the dustproof sheet 8 is pushed open and a portion where the operation lever 12 is closed can be almost eliminated.

(Embodiment 4) A case in which only the conventional metal plate operating lever contacts the dustproof sheet with the material of the operating lever base and the dustproof sheet that comes into contact when the operating lever of the slide type variable resistor is moved linearly. And a case in which a dust-proof sheet is made of conventional polyethylene and polyethylene terephthalate having a high heat-resistant temperature, in contrast to a case in which a circular or chamfered projection is provided at the base of the metal plate operation lever at the base portion with resin. Are shown in Table 1 below.

[0035]

[Table 1]

As is clear from the results, by providing a protrusion having a circular or chamfered end surface with resin at the base of the operating lever made of a metal plate, both characteristics are improved, and the dustproof sheet is made to have a heat resistant temperature. By using high polyethylene terephthalate, the heat resistance is further improved.

[0037]

As described above, according to the present invention, the end of the operation lever is in contact with the slit of the dustproof sheet even if the number of operations is increased or the device is placed in a high-temperature atmosphere in a long-time use. It does not degrade the operation feeling by roughening the surface or leaving a trace of the corner of the operation lever, and also removes the gap between the part where the operation lever of the slit of the dustproof sheet is pushed open and the part where it is closed. An advantageous effect that the size can be reduced and the dustproof performance is improved can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a slide type variable resistor according to a first embodiment of the present invention.

FIG. 2 is a top view of the same.

FIG. 3 is a top view of a main part showing another shape of the protrusion.

FIG. 4 is a sectional view of a main part of a slide type variable resistor according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a slide type variable resistor according to a third embodiment of the present invention.

FIG. 6 is an external perspective view of a conventional slide type variable resistor.

FIG. 7 is a sectional view of the same.

FIG. 8 is a top view of the same.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 cover 1A opening 2 resistive substrate 3 resistive element layer 6 sliding contact 8 dustproof sheet 8A slit 8B intermediate portion 11, 14, 15 slider 12, 14A operating lever 12A cutout 13, 14, B, 15A protrusion

Claims (6)

[Claims] 1. An elongated box-shaped cover having an open bottom surface having a narrow opening along a longitudinal direction on an upper surface, a resistive substrate coupled to close an open surface of a lower surface of the cover, and a resistive substrate on the resistive substrate. A resin slider having a sliding contact on its lower surface which resiliently contacts the resistive element layer formed in the cover and slidably accommodated in the cover; and a slit corresponding to the center position of the narrow opening of the cover. A dustproof sheet made of a flexible resin fixed to the upper surface of the cover so as to close the narrow opening, and penetrating through the dustproof sheet so as to be sandwiched by slits of the dustproof sheet so as to protrude upward. A vertically long plate-shaped operation lever provided integrally with the slider and both ends of the portion between the dustproof sheet at the base of the operation lever are formed of resin integral with the slider, and the end surface is circular or chamfered. From the protrusion Slide type variable resistor. 2. The slide-type variable resistor according to claim 1, wherein the operation lever is formed by insert-molding a metal plate into a resin forming the slider. 3. A slide-type variable resistor according to claim 2, wherein cut portions are provided on both sides of a portion between the dustproof sheet at the base of the operation lever made of a metal plate, and protrusions are integrally formed with resin outside the cut portions. vessel. 4. The slide-type variable resistor according to claim 1, wherein the operation lever is formed of resin integrally with the slider. 5. The slide type according to claim 1, wherein the protrusions formed at both ends of the portion between the dustproof sheet at the root of the operation lever are tapered so that the lower part is wider than the upper part. Variable resistor. 6. The slide-type variable resistor according to claim 1, wherein the slider is formed of polyacetal resin, and the dust-proof sheet is formed of polyethylene terephthalate.