US3566330A

US3566330A - Variable resistor of sliding type

Info

Publication number: US3566330A
Application number: US761035A
Authority: US
Inventors: Katsumi Ichikawa; Tadasi Yano
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 1967-12-21
Filing date: 1968-09-20
Publication date: 1971-02-23
Anticipated expiration: 1988-02-23

Abstract

IMPROVEMENTS ON A VARIABLE RESISTOR OF THE SLIDING TYPE AND MORE PARTICULARLY THE STRUCTURE OF FITTING A SLIDER AND A CONTACT ELEMENT TO A RESISTOR IS DISCLOSED, PREVENTING THE LATERAL ROLLING OF THE SLIDER AND MAKING THE FITTING

POSITION OF THE CONTACT ELEMENT ADJUSTABLE TO CONTROL THE VALUE OF RESISTANCE SIMPLY.

Description

Feb- 23, 1971 KATsUMl lcHlKAwA ET AL VRIABLE .RESISTOR OF SLDING TYPE s sheets-shea 1 Filed Sept. 20, 1968 Feb. 23; 1971 KATSUMl |CH|KAWA ETAL 3,566,330

v VARIABLE REsIsToR oF sLIDING TYPE Filed Sept. 20, 1968 v 3 Sheets-Sheet 2 F/G. .9 I y CP/03 Feb. 23,1971 `KATSUMI lcHlKAwA ET Al. 3,566,330

I f VARIABLE REsIsToR oF sLIDING TYPE Filed sept. 2o, .196e s sheets-sheet s United States `Patent O U.S. Cl. 338-133 8 Claims ABSTRACT F THE DISCLOSURE Improvements on a variable resistor of the sliding type and more particularly the structure of tting a slider and a contact element to a resistor is disclosed, preventing the lateral rolling of the slider and making the tting position of the contact element adjustable to control the value of resistance simply.

BACKGROUND OF THE INVENTION Field of the Invention This invention relates in general to a variable resistor of the sliding type and more particularly to a variable resistor of the sliding type in which the mechanism of a slider is improved and the position of a contact element fitted to the slider is made adjustable after assembling.

Description of the Prior Art A prior art variable resistor of the sliding type has a structure in which slider riding on a guide rod provided in the center of a case is slided by manipulating an actuating lever. When a lateral force is applied to the actuating lever, it suffers a large deflection. A minute crack on the surface of the guide rod causes roughness or blockage during manipulation so that smooth sliding is not obtainable. Such a lateral dellection has made it impossible to give a constant pressure of Contact element on the resistance element.

Generally, a variable resistor of the duplex sliding type is often used as volume or tone control of a stereo set. In this case, unless the resistances in both variable resistors vary equally, a true stereo is not obtained as the volume or the tone of the speakers on both sides differs. A certain unbalance is brought forth depending on the variation of resistance characteristic and the dimension of the resistance element. However, it is errors in assembling the variable resistor which mainly influence the unbalance. A defect of the conventional duplex type variable resistor is that the position of a contact element with respect to the resistor has a large influence on the value of resistance and causes a deviation between both resistors.

SUMMARY OF THE INVENTION Therefore, one object of this invention is to provide a variable resistor of the Asliding type obviating the abovementioned roughness and blockage and applying a constant pressure of the contact element on the resistance element.

Another object of this invention is to provide a variable resistor of the sliding type in which the position of a contact element fitted to the slider is made adjustable after assembling so that any error that might occur during assembly is eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional front view of a prior art variable resistor of the sliding type.J

ice

FIG. 2 is a longitudinal sectional front view of a variable resistor of the sliding type according to one embodiment of this invention.

FIG. `3 is a perspective view showing the disassembled main portion of the above variable resistor of the sliding type.

FIG. 4 is a longitudinal sectional front View of a variable resistor of the sliding type according to another embodiment of this invention.

EFIG. 5 is a perspective view showing the disassembled main portion of the above variable resistor of the sliding type.

FIG. 6 is a top view of a variable resistor of the sliding type according to a further embodiment of this invention.

'FIG. 7 is a cross-sectional view of the above Variable resistor of the sliding type.

FIG. 8 is a perspective view showing the disassembled main portion of the above variable resistor of the sliding type.

FIG. 9 is a longitudinal cross-sectional view of a variable resistor of the sliding type according to another embodiment of this invention.

FIG. 10 is a perspective view showing the disassembled main portion of the above variable resistor of the sliding type.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A prior art variable resistor of the sliding type will be explained hereinafter with reference to FIG. l. 1 is a metal case made by metal plate processing, a guide window 2 being formed in one portion of the top surface and a base 3 being tted on the bottom wall. 4 is a slider made of a rectangular insulating material with an actuating lever r5 on its top surface penetrating the guide window 2 and with a groove portion in the bottom surface riding on a guide rod `6 positioned in the center of the case. 7 shows mails provided in the corner of the top surface of the slider 4 to touch the inn'er top surface of the case 1. 8 and 8 are contact elements having contact portions 9, 9', 10 and 10' tted to the bottom of the slider 4. These contact portions are slid on the resistance elements 11 and 11' and

contact plates

12 and 12. which are provided on the base 3 in parallel with one another. 13, 13', '14 and 14' are wiring terminals provided outside the base 3 and are connected to the ends of resistance elements -11 and 11' and

contact plates

12 and 12 respectively.

In this structure, the slider 4 riding on the guide rod 6 is slid by manipulating the actuating lever 5. So, when a lateral force is applied to the actuating lever 5, it suffers a large deflection. Further, minute cracks existing on the surface of the guide rod 6 cause roughness or blockage during manipulation and prevent a smooth slide. The lateral deflection of the slider presses down the contact elements 8 and 8' thereunder making it difficult to give a constant pressure of the contact element on the resistance element.

This invention eliminates the above-mentioned roughness and blockage and provides a structure in which a constant pressure is kept applied on the resistance element.

Explanation of one embodiment of this invention will be made hereunder with reference to FIGS. 2 and 3.

-15 is a metal case made of metal plate with a guide window 16 on one portion of the top surface. A base 18 made of molded material with

protrusions

17 and 17 on both sides of the top surface is fitted to the bottom surface of the case 1S. 19 is a slider of insulating material, the bottom surface of which is disposed on the

protrusions

17 and 17. 20 is a rectangular projection provided on the top of the slider 19A and slidingly fitted into the guide window 16.

Protrusions

21 and 21 on both sides of the slider 19 contact with `the inner top surface of the case 15. The bottom surface of the sliding body 19 is on the

protrusions

17 and 17 by manipulating an actuating lever 22 provided on the rectangular projection 20. Contact elements 23 provided under the slider and having a contact portion is arranged to slide on a resistance element 24 and contact plate 25 which are provided in parallel with each other on the base 18. 26 and 27 are wiring terminals provided outside the case 15 and connected to the end portions of the resistance element 24 and the contact plate 25 respectively.

As is seen in the above-mentioned structure of the inventive variable resistor of the sliding type, since the bottom surface of the slider 19 is positioned on the protrusions 17 and .17' of the base 18, a constant pressure is always applied on the resistance element 24. Further, as these sliding portions are made of molded material, they provide for a very smooth slide action. Even if a lateral force is applied to the actuating lever 22, the rectangular projection 20 provided on the slider 19 touches the guiding window thereby to prevent the rolling of the actuating lever 22.

Next, explanation of another embodiment of this invention will be made with reference to FIGS. 4 and 5.

In these figures, 15 is a metal case made of sheet metal, a guide window 16 being formed in one portion of the top surface. A base 18 of molded material having protrusions 17 and 17' on both sides of the top surface is provided under the case 15. 19 is a slider of insulating material. An actuating lever 22 is provided on the top of the slider, penetrating the guide window 16. Both sides of the bottom surface of the slider 19 are shaped into

ridges

28 and 28 which are made to contact with the protrusions .17 and :17. The

protrusions

21 and 21 provided on both sides of the top surface of the slider 19 contact with the inner top surface of the case 15. The ride portions 28 and 28' are slid by manipulating the actuating lever 22. Contact elements 23 provided under the slider 19 and having a contact portion are arranged to slide on a resistance element 24 and a contact plate 25. 26 and 27 are wiring terminals provided outside the base 18 and connected to the end portions of the resistance element 24 and the contact plate 25 respectively.

As is seen in the structure of the above inventive variable resistor of the sliding type, even if a lateral force is applied tothe actuating lever 22, the contact between the

ridge portions

28 and 28 on both sides of the bottom surface of the slider 19 and the protrusions 17 and 17' provided on both sides of the top surface of base 18 can prevent the lateral rolling of the actuating lever 22. Further, since these sliding portions are made of molded material, the sliding action becomes extremely smooth.

As is evident from the above description, the lateral movement of the actuating lever can be prevented by a simple structure, and a smooth sliding action is obtained. Therefore, the practical merit of this invention is very large.

Generally, a variable resistor of the duplex sliding type is often used for the volume or tone control in a stereo set. In this case, unless the resistances of the two variable resistors vary equally during adjustment, both speakers differ in volume or tone so that any true stereo is not obtained. The variation of resistance characteristic and the dimension of the resistance element cause a certain unbalance. However, it is the errors in the step of assembling that have a large influence on such an unbalance. Namely, the position of a contact element with respect to the resistance element occasionally suffers a large deviation.

This invention eliminates such a defect using a simple structure, whereby the contact position is adjustable after the resistors are assembled.

Explanation of another embodiment of this invention will be made hereunder with reference to FIGS. 6 to 8.

In these figures, 101 is a base made of an insulator, on which two

resistance elements

102 and 103 and two

contact plates

104 and 105 are provided. Pairs of resistance elements and

contact plates

102 and 104, and 103 and 105, constitute individual resistors. The base 101 is covered with a case 106 made of metal sheet bending processing. An elongated hole 107 is formed in the top surface of the case 106. A slider 109 with an actuating lever 108 penetrating the elongated hole 107 is disposed in the case 106. Two contact elements 110 and 111 -are fitted on the bottom surface of the slider 109 to be in contact with the

resistance elements

102 and 103 and the

contact plates

104 and 105. As shown in FIG. 8, these contact elements 110 and 111 are fixed into protrusions 112 provided on the bottom surface of the slider 109. One of them 110 is perfectly fixed by the protrusions 112 while the other element 111 is held by a cut-and-raised opening 113 slightly larger than the size of the protrusions 112. A through hole 115 is perforated in the extended portion 1'14 of the contact element 111 and positioned on a cutaway portion 116 which is to be aligned with the elongated hole 107. Therefore, the through hole 115 can be seen through from outside by way of the Ielongated hole 107. A slender rod is inserted through the hole 115 and moved in the lateral direction so that the position of the contact element 111 with respect to the resistance element 103 may shift and the resistances of both contact elements 110 and 111 will be equal.

Lastly, a further embodiment of this invention will be explained with reference to FIGS. 9 and 10, in which 101 is a base made of an insulating material. Two

resistive elements

102 and 103 and two

contact plates

104 and 105 are fitted on the base 101. Pairs of resistance elements and

contact plates

102 and 104, and 103 and 105 constitute individual resistors. The base 101 is covered with a case 106 made of metal sheet bending processing. An elongated hole 107 is formed in the top surface of the case 106. A slider 109 with an actuating lever 108 penetrating the elongated hole 107 is disposed in the case 106. Two contact elements 110 and 111 are fitted on the bottom surface of the slider 109 and contact with the

resistance elements

102 and 103 and the

contact plates

104 and 105. As shown in FIG. l0, these contact elements 110` and 111 are fixed into the protrusions 112 provided on the bottom surface of the slider 109. One of them 110 is perfectly fixed by the protrusion 112 while the other 111 is held by an elliptic fitting hole 118 having a slightly larger size than that of the protrusion 112. Namely, the contact element 111 is fixed into the protrusion 112 but can be slid. A through hole 115 is perforated in the extended portion 114 of the contact element 111 and positioned on a cutaway portion 116 which is to be aligned with the elongated hole 107. Therefore, the through hole 115 can be seen through from the outside by way of the elongated hole 107. A slender rod is inserted through the hole 115 and moved in the lateral direction so that the position of the contact element 111 with respect to the resistance element 103 may shift and the resistances of both contact elements 110 and `111 will be equal.

As is seen from the `above-mentioned structure of the inventive slide type variable resistor, a contact element is fixed into a protrusion provided under the slider by either a cut-and-raised opening or in elliptic hole which has a slightly larger size than that of the protrusions. The through hole formed in one portion of the contact element is transparent. So, the position of the contact element with respect to the resistance element can be varied through this hole. In the case of a variable resistor of the duplex sliding type the resistances of the two contact elements can be adjusted to be equal. Therefore, this variable resistor of the duplex sliding type is very effective if employed in a stereo set. Also, a variable resistor of the single sliding type though not shown in the above embodiments is useful as a minute adjustment of the resistance is possible. Due

to such a simple structure with only holes in the contact elements these variable resistors of the sliding type can be manufactured cheaply. Therefore, the practical advantage of this invention is very large.

What is claimed is:

1. A variable resistor of the sliding type comprising a case having a guide window in one portion thereof; a base of molded material provided on the bottom surface of said case and having protrusions on both sides of the top surface; a slider of insulating material arranged in said case so that the bottom surface is positioned on said protrusions of said base; a protrusion located on the bottom surface of said slider disposed between said case and said base on 'which resistance elements and contact plates are provided; a contact element having a cut-andraised opening with a slightly larger dimension than that of said protrusion xed into said protrusion, one portion of said contact element being provided with a through hole which can be seen through by way of an elongated hole formed in said case; and a rectangular projection provided on the top surface of said slider to be slidingly tted into said guide window.

2` A Variable resistor of the sliding type comprising a case having a guide window in one portion thereof; a base of moulded material provided on the bottom surface of said case and having protrusions on both sides of the top surface; a slider of insulating material arranged in said case so that the bottom surface is positioned on said protrusions of said base; a protrusion located on the bottom surface of said slider disposed between said case and said base on which resistance elements and contact plates lare provided; a contact element having an elliptic hole with a slightly larger dimension than that of said protrusion fixed into said protrusion, one portion of said contact element being provided with a through hole which can be seen through by way of an elongated hole formed in said case; and a rectangular projector provided on the top surface of said slider to be slidingly fitted into said guide window.

3. A variable resistor of the sliding type according to claim 2, wherein a cutaway portion is formed in one portion of said contact element so as to be seen through by way of said elongated hole formed in said case.

4. A Variable resistor of the sliding type according to claim 1 wherein a cutaway portion is formed in one portion of said contact element so as to be seen through by way of said elongated hole formed in said case.

5. A Variable resistor of the sliding type comprising a case having a guide window in one portion thereof, a base of molded material provided on the bottom surface of said case and having molded protrusions on both sides of the top surface, a slider of insulating material having cutaway portions on both sides of the bottom surface of said slider, said slider being arranged in said case in such a manner that said cutaway portions may engage slidably with said protrusions provided on said base; further cornprising a protrusion on the bottom surface of said slider disposed between said case and said base on which resistance elements and contact plates are provided, and a contact element having a cut-and-raised opening with a slightly larger dimension than that of said protrusion Xed into said protrusion, one portion of said contact element being provided with a through hole which can be seen through by way of an elongated hole formed in said case.

6. A variable resistor of the sliding type comprising a case having a guide window in one portion thereof, a base of molded material provided on the bottom surface of said case and having molded protrusions on both sides of the top surface, a slider of insulating material having cutaway portions on both sides of the bottom surface of said slider, said slider being arranged in said case in such a manner that said cutaway portions may engage slidably -with said protrusions provided on said base; further comprising a protrusion on the bottom surface of said slider disposed between said case and said base on which resistance elements and contact plates are provided, and a contact element having an elliptical hole with a slightly larger dimension than that of said protrusion fixed onto said protrusion, one portion of said contact element being provided with a through hole which can be seen through by way of an elongated hole formed in said case.

'7. A variable resistor of sliding type according to claim 5, wherein a cutaway portion is formed in one portion of said contact element so as to be seen through by way of said elongated hole formed in said case.

8. A variable resistor of sliding type according to claim 6, wherein a cutaway portion is formed in one portion of said contact element so as to be seen through by way of said elongated hole formed in said case.

References Cited UNITED STATES PATENTS 2,242,327 5/ 1941 Rubinstein 338-183 2,954,537 9/1960 Scott, Jr., et al 338-180 3,178,664 4/1965 Thoele 338-183 3,238,488 3/1966 Langenbach et al. 338-183X 3,271,721 9/1966 Gordon 338-180X 3,412,361 11/1968 Lovejoy et al. 338-183X THOMAS J. KOZMA, Primary Examiner U.S. Cl. X.R.