US 3743999 A
A lever-operated variable resistor which retains the advantages of the conventional linear slide variable resistor in which the position of a lever or knob is identified at a glance, while eliminating the drawback that fine adjustment is difficult to achieve. Gear engagement is utilized to enable a contactor to cover a longer sliding distance with respect to a small sliding angle of the lever, thereby making possible the use of high power for a resistance element and improving the adjustability of resistance value.
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Description (OCR text may contain errors)
United States Patent [191 Miyashita [451 July 3,1973
[ LEVER-OPERATED VARIABLE RESISTOR  Inventor: Akitoshi Miyashlta, Suita, Japan  Assignee: Matsushita Electric Industrial Co.,
Ltd., Osaka, Japan  Filed: Oct. 26, 1971  Appl. No.: 192,184
 Foreign Application Priority Data 3,539,748 11/1970 Neumeier 338/162 X 2,513,677 7/1950 Rigert 338/184 X 3,242,451 3/1966 Mathison 338/184 X 3,388,365 6/1968 Wood 3,428,887 2/1969 Miller Murakami 338/184 X Primary Examiner-Richard B. Wilkinson Assistant ExaminerU. Weldon Attorney-Stevens, Davis, Miller & Mosher 5 7 1 ABSTRACT A lever-operated variable resistor which retains the advantages of the conventional linear slide variable resistor in which the position of a lever or knob is identified at a glance, while eliminating the drawback that fine adjustment is difficult to achieve. Gear engagement is utilized to enable a contactor to cover a longer sliding distance with respect to a small sliding angle of the lever, thereby making possible the use of high power for a resistance element and improving the adjustability of resistance value.
4 Claims, 2 Drawing Figures LEVER-OPERATED VARIABLE RESISTOR This invention relates to a lever-operated variable resistor.
This invention provides a lever-operated variable resistor with a unique construction which retains the advantage of a widely-used conventional linear slide variable resistor in which the position of a lever or knob is identified at a glance.
The above and other objects, features and advantages will be made apparent by the detailed description taken in conjunction with the accompanying drawings, in which:
FIG. 1 shows a perspective view of the lever-operated variable resistor embodying the present invention; and
FIG. 2 shows a perspective view of inner parts of the resistor according to the invention with its cover removed.
Referring to the drawings, the reference numeral 1 shows a metal cover with its under side open. On the open under side of the cover 1 is fixed a base plate 2 by means of a plurality of bent legs 3 of the cover 1. A
shaped gear 20. The small gear 10 in mesh with the teeth of the fan-shaped gear 20 is accordingly rotated. As a result, the contactor carrier 7 rotates, and thccontactor 12 slides on the resistance element 13. This makes it possible to take out a desired variable resistance from between one of the outer terminals 14 and the middle terminal 16.
' The variable resistor according to the invention may be mounted on external equipment by means of fixing slot 4 is formed on the front wall of the metal cover 1 V and two fitting apertures 5 and 6 are provided on the top of the cover 1. Numeral 7 shows a contactor carrier of insulating material interposed between the metal cover 1 and the base plate 2. A protruded shaft 8 integrally formed on the under side of the contactor carrier 7 is fitted rotatably in an aperture 9 formed on the backward of the base plate, so that the contactor carrier 7 is rotatable with the protruded shaft 8 as a supporting point. The protruded shaft 8 may be formed independently of the contactor carrier 7. Numeral 10 shows a small gear mounted on the upper side of the contactor carrier 7. On the small gear 10 is formed a protrusion 11 to be fitted in the aperture 6 formed on the backward portion of the top of the metal cover 1. Numeral 12 shows a contactor fixed on the under side of the contactor carrier 7, which is in contact with a resistance element 13 mounted on the base plate 2. Numeral 14 shows outer terminals led from both ends of the resistance element 13, and numeral 15 a contactor which is maintained in contact with part of the contactor l2 and from which a middle terminal 16 is taken out. Numeral 17 shows a lever with one of its end fixedly caulked on a shaft 18, the other end thereof projecting through the slot 4 formed on the metal cover 1. The lower end of the shaft 18 is fitted in an aperture 19 formed on the front portion, near to the operator, of the base plate, while the upper end thereof is fitted in the aperture 5 formed on the front portion, near to the operator, of the metal cover 1. Numeral 20 shows a fan-shaped gear which, like the lever 17, has one of its ends caulked on the shaft 18 and the other end thereof being in mesh with the small gear 10. Numeral 21 shows cut-down stops on the back of the top of the metal cover 1, which limit the rotational movement of the lever 17 as they come into contact with the sides of the fan-shaped gear 20.
The operation of the resistor. according to the invention with the above-described construction will be now explained in detail. Moving the lever 17 in the direction indicated by an arrow causes the shaft 18 to rotate around it supporting point on the apertures 5 and 19, which in turn causes a circular movement of the fanapertures usually formed on the front of the metal cover 1.
The lever 17, the fan-shaped gear 20, and the shaft 18 which were assembled into an integral unit in the above-described embodiment may be formed as a single unit from the beginning. The same can be said of the relation between the small gear 10 and the contactor carrier 7. i
The lever-operated variable resistor according to the invention with the above-described construction has the advantage that the value of resistance is identified by a glance at the position of the lever or knob. Also, the gear engagement provides a longer sliding distance of the contactor for a small sliding angle of the lever, facilitating not only the upgrading of the resistor for high power operation but the realization of characteristics of variation. This is applied most suitably for balancing the volume of sounds coming out of stereo speakers and adjusting the volume and tone of an electronic musical instrument. Further, the use-of gears makes the resistor compact, simple in construction and hence low in cost.
What is claimed is:
l. A lever-operated variable resistor comprising a cover with its lower side open, a base plate attached to the opening of said cover on the lower side thereof, a contactor carrier interposed between said cover and said base plate, a protruded shaft mounted on theunder side of said contactor carrier and rotatably fitted in an aperture formed on said base plate, a small gear located on the upper side of said contactor carrier, a protrusion provided on said gear for being fittedin an aperture formed on an end of said cover, a shaft with its lower and upper ends fitted in apertures formed on said base plate and cover respectively, a lever and a sectoral gear mounted on said shaft, said lever being projected through a slot formed on the front wall of said cover, said sectoral gear engaging with said small gear, a contactor fixed on said contactor carrier, and a resistance element mounted on said base plate and maintained in contact with said contactor, wherein an outer terminal is taken out from each of the ends of said resistance element and a middle terminal is" led from a contactor maintained in contact with part of said resistance element.
2. A lever-operated variable resistor according to claim 1, wherein said cover consists of metal.
3. A lever-operated variable resistor according to claim 1, further comprising a couple of stop protrusions formed on the top of said cover for limiting the rotational angle of said lever when the sides of said sectoral gear come into contact with said stop protrusion.
4. A lever-operated variable resistor according to claim 3, wherein said cover consists of metal.
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