JPH0423286Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a semi-fixed variable resistor, and particularly to an adjustment knob for adjusting the resistance value from the back side.

[Conventional technology]

Conventionally, many semi-fixed variable resistors have been known in which a desired resistance value is obtained by changing the contact position by rotating and sliding a slider piece on a resistance layer formed on the surface of an insulating substrate. This type of semi-fixed variable resistor is attached to a printed wiring board,
After it is connected to the electric circuit, the resistance value is finely adjusted from the outside using an adjustment jig such as a screwdriver, so a groove for engaging the jig is formed at one end of the adjustment knob fixed to the slider piece. has been done.

FIG. 5 shows an example of a conventional semi-fixed variable resistor, in which a resistance board 2 whose surface is coated with a ring of electrical resistance material is housed in the bottom of an insulating case 1. One end 3a of a slider piece 3 made of a conductive spring material is in elastic contact with. This slider piece 3 is fixed to a first adjustment knob 4 rotatably attached to the insulating case 1, and one end 3a slides on the resistance board 2 as the adjustment knob 4 rotates. In addition, a second adjustment knob 5 is rotatably attached to the opposite side of the insulating case 1 from the side where the first adjustment knob 4 is attached. is the slider piece 3
is fixed. Therefore, if the second adjustment knob 5 is rotated using a jig, the slider piece 5 will be moved against the resistance board 2.
Slide the top in the same way as above.

The first and second adjustment knobs 4 and 5 have grooves 4a and 4a, respectively, which can be engaged with a jig such as a screwdriver.
5b is formed, and when the variable resistor is attached to the printed wiring board 6 at the position shown by the two-dot chain line in the figure, the groove 4a , 5b, the resistance value can be adjusted. Further, in the figure, 7 and 8 are terminals connected to both terminals of the resistance board 2.

[Problem that the invention attempts to solve]

By the way, in the case of the above-mentioned semi-fixed variable resistor, the second adjustment knob 5 is formed by so-called header processing, in which material is put into a mold and tapped to form the desired shape. , continuous machining caused scratches and machining efficiency was low.

Therefore, for the purpose of improving machining efficiency, the present applicant developed a flange-like plate material having a shaft portion 5a and a groove 5b.
We previously filed an application for an adjustment knob for a semi-fixed variable resistor that was made by folding and integrating a flange-like plate material with According to this earlier application, since the second adjustment knob can be formed by press working using a metal plate, automation is realized and it is an extremely effective means for improving the production industry, but it is not without problems. do not have. In other words, because a slit (groove) for rotational operation is formed in one of two flange-shaped plates that are folded and stacked one on top of the other, the depth of the slit cannot be greater than the thickness of one flange-shaped plate. Therefore, when the tip of a jig such as a screwdriver is inserted into the slit and the adjustment knob is rotated, there is a problem that the jig tends to come off from the slit. especially,
This tendency becomes more pronounced as the thickness of the adjustment knob becomes thinner as semi-fixed variable resistors become smaller in recent years.

Therefore, an object of the present invention is to provide a semi-fixed variable resistor that can continuously form an adjustment knob for adjusting the back side by press working and that can ensure engagement with a jig during adjustment. .

[Means for solving problems]

In order to achieve the above object, the present invention includes a substrate on which a resistance layer is formed, a first adjustment knob provided with a slider piece that can slide on the resistance layer, and a first adjustment knob provided on the substrate. The slider piece includes a shaft portion inserted through the shaft portion and a second adjustment knob having a flange extending from the shaft portion, and the slider piece rotates and slides on the resistance layer to change the contact position. In the semi-fixed variable resistor that can obtain a resistance value of It consists of two flange parts,
This second flange portion is characterized in that a raised portion is formed, and a slit for rotational operation is formed within the raised portion.

[Effect]

That is, according to the above means, a clearance corresponding to the protuberance is formed between the flange portion in which the slit for rotational operation is bored and the flange portion in which the shaft portion is extended, so that the slit in the adjustment jig is The amount of insertion can be increased, and the adjustment jig can be prevented from coming off from the slit when the adjustment knob is rotated.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

First, the configuration of a semi-fixed variable resistor according to an embodiment of the present invention will be explained using FIGS. 3 and 4. In these figures, reference numeral 9 indicates a second adjustment knob for adjusting the back surface, and the second adjustment knob 9
is made of a single metal plate, and includes a hollow shaft portion 9a whose one end is caulked and fixed to the slider piece 3, a first flange portion 9b provided at the other end of the shaft portion 9a, and a first flange portion 9b provided at the other end of the shaft portion 9a. The second plate folded and stacked on the flange part 9b of
flange portion 9c. The first flange portion 9b has locking claws 9d bent toward the second flange portion 9c at three locations on its periphery, and the second flange portion 9c has locking claws at three locations on its periphery. A raised part 9 having a notch part 9e that engages with the part 9d and having a stepped shape formed in the center of the notch part 9e.
It has a rectangular slit 9f in h, and further has flange-like stopper portions 9g at two locations on the periphery. On the other hand, one cut-and-raised piece 7a is provided near the bent portion of the terminal 7, and this cut-and-raised piece 7a is located within the rotation locus of the stopper portion 9g. Therefore, when a jig such as a screwdriver is engaged with the slit 9f of the second adjustment knob 9 and rotated, the rotational force is
The first flange portion 9b is connected to the lower surface of the second flange portion 9c via a folding portion, and is fixed to the tip of the shaft portion 9a via the shaft portion 9a integrally formed with the first flange portion 9b. This is transmitted to the slider piece 3 which has been moved, and thereby the slider piece 3 slides on the resistor board 2. Also, at this time, the second adjustment knob 9
The rotation angle is regulated by one of the stopper portions 9g colliding with the cut-and-raised piece 7a of the terminal 7. Note that the other configurations are the same as those of the conventional example shown in FIG. 5, so detailed explanations will be omitted by giving the same reference numerals.

Next, a method of manufacturing the second adjustment knob 9 will be explained with reference to FIGS. 1 and 2.

First, a hoop-shaped metal plate having a predetermined thickness is press-formed to form a drawn hollow shaft portion 9a as shown in FIG. 1, and a flat plate portion extending perpendicularly to the shaft portion 9a. This flat plate part has a peripheral edge 3
The first flange portion 9b has locking claws 9d at several locations.
and a second flange part 9c, which has three notches 9e and two stopper parts 9g on the periphery, and a stepped raised part 9h and a rectangular slit 9f in the center. Flange part 9
b and 9c are connected by a narrow portion. Since the slit 9f is formed within the plane of the raised portion 9h that is pressed into a convex shape with respect to the peripheral portion of the second flange portion 9c, the material strength around the slit 9f is increased.

Next, the flat plate part is folded in the direction of the arrow along the line A--A in FIG. 1, and the second flange part 9c is superimposed on the first flange part 9b. Thereafter, as shown in FIG. 2, each of the locking claws 9d is bent toward the second flange portion 9c, and these locking claws 9d are engaged with each of the notches 9e. As a result, the second adjustment knob 9 is formed, which includes a flange in which the two flange portions 9b and 9c are folded and overlapped, and a shaft portion 9a extending orthogonally from the flange.

The second adjustment knob 9 formed in this way
Since a gap 10 corresponding to the amount of bulge of the raised portion 9h is formed between the second flange portion 9c and the first flange portion 9b around the slit 9f, the tip of the jig 9 such as a driver can be inserted not only into the slit 9f but also into the gap 10 at the back thereof, and therefore, it is possible to reliably prevent the jig from coming off from the slit 9f during rotation operation. Furthermore, this second adjustment knob 9 has a raised portion 9h that is bulged and pressed into a convex shape with respect to the peripheral portion of the second flange portion 9c.
Since the slit 9f is formed within the plane of the slit 9f, the material strength around the slit 9f is increased. As mentioned above, the flange has a thick wall structure in which the two flange parts 9b and 9c are folded, and these flange parts 9
b and 9c are overlapped with their respective locking claws 9d and notches 9e engaged, so they are sufficiently strong against the rotational force during the rotation described above, and the folding portions 9h are deformed during the rotation operation. There is no problem with doing so. Further, a first flange portion 9 having a shaft portion 9a
A second plate having a locking claw 9d on the b side and a slit 9f.
Since the notch 9e is formed on the flange portion 9c side of the second flange portion 9c, even if the tip of the bent locking pawl 9d protrudes from the surface of the second flange portion 9c, rotational operation will not be hindered. The engagement between the retaining pawl 9d and the notch 9e can be ensured.

In addition, in the above embodiment, a case was explained in which three locking claws 9d formed at approximately 90-degree intervals and three notches 9e formed at approximately 90-degree intervals, but these locking claws The number and formation positions of the notches 9d and the notches 9e can be changed as necessary.

Further, in the above embodiment, the cutout portion 9e was cited as an example of the locking portion that engages with the locking pawl 9d, but this engaging portion engages with the locking pawl 9d within the plane of the second flange portion 9c. If it fits, its shape is not specified, and therefore, a protrusion extending from the periphery of the second flange portion 9c or a hole drilled near the periphery of the second flange portion 9c is used as the notch. It is also possible to use it in place of 9e.

[Effect of idea]

As explained above, according to the present invention, the shaft part, flange, slit for rotation operation, etc. necessary for the adjustment knob for adjusting the back side can be continuously machined from a single metal plate by press forming. Not only that, but the desired space is formed at the back of the slit, which increases the engagement force between the adjustment jig and the slit.Therefore, it is a semi-fixed type that is excellent in mass production and allows for reliable adjustment work. We can provide variable resistors.

[Brief explanation of the drawing]

1 to 4 relate to an embodiment of the present invention, in which FIG. 1 is a perspective view showing the second adjustment knob in an expanded state, FIG. 2 is a perspective view of the second adjustment knob, FIG. 3 is a sectional view of a semi-fixed variable resistor, FIG. 4 is a bottom view of the semi-fixed variable resistor, and FIG. 5 is a sectional view of a conventional semi-fixed variable resistor. 2... Resistance board, 3... Slider piece, 4... First
Adjustment knob, 7, 8...terminal, 9...second adjustment knob, 9a...shaft, 9b...first flange, 9c...second flange, 9d...locking claw , 9e...notch, 9f...slit, 9g...
...stopper part, 9h...raised part.

Claims (1)

[Scope of utility model registration request] A substrate having a resistance layer formed on its surface, a first adjustment knob provided with a slider piece that can slide on the resistance layer, a shaft inserted through the substrate, and a shaft extending from the shaft. and a second adjustment knob having a flange, the slider piece rotates and slides on the resistance layer to change the contact position, thereby obtaining a desired resistance value. , the second adjustment knob consists of a first flange part integrally formed on one end of the shaft part and a second flange part folded back and overlapped with the first flange part, and the second flange part 1. A semi-fixed variable resistor, characterized in that a raised part is formed in the part, and a slit for rotational operation is formed in the raised part.