US3372359A - Coordinated control for variable resistors - Google Patents

Description

G. K. WILSON COORDINATED CONTROL FOR VARIABLE RESISTORS Filed Jan. 50, 1967 'n m21 5, ma@ 3,372,359

2 Sheets-Sheet March 5, 41968` G, K W|| 50N 3,372,359

COORDINATED CONTROL FOR VARIABLE RESISTORS Filed Jan. 30, 1967 2 Sheets-Sheet E /NVENTOR GORDO/V K. WILSON BY 4%@ M l AT;'YS.

United States Patent O Filed `lan.. 30, 1967, Ser. No. 612,499 9 Claims. (Cl. 3138-128) ABSTRACT E THE DISCLGSURE ably engaging elongated slots in each of the carriers thereby to obtain coordinated control wipers and associated resistors when the free end of the control lever is moved. Several variable resistors may be positioned for coordinated control with suitable moditication of the slide or wiper positioned on the carriers.

and adjustment of the This invention relates to a coordinated control for a plurality of variable resistors. Controls of this general type are shown in the prior art, however, these have not received widespread commercial acceptance possibly because of the prohibitive cost and disproportionate size of the finished article. In large part, the prohibitive cost may be attributed to the expense incurred in the manufacture of precision-made parts to obtain the exacting results desired in coordinated control of variable resistors. Related to this problem is the ditticulty experienced in assembly to obtain a precision device which will meet the demands of the industry.

The present invention obviates the problems of the prior art through the provision of a new and improved design. A housing is formed by a non-.conducting material consisting of a terminal housing of box-like form. Provided along the side walls of the terminal housing are a plurality of -shaped notches disposed on axes at an angle to each other. First and second non-conducting carriers have opposite ends in the form of trunnions While the intermediate sections are generally C-shaped or U- shaped in form. The trunnions are positioned in the U- shaped notches at right angles to each other. Each of the carriers mounts at least one conducting wiper member having a distal portion which engages a stationary terminal mounted in the terminal housing and having a lead connecting portion extending from the bottom or" the terminal housing. Disposed along the side walls of the terminal housing are a plurality of resistors, each of which may be of any type such as Wire wound variety, cermet type or the like. Each ofthe resistors is provided with conducting terminals at opposite end portions, which terminals have lead connecting portions projecting through the bottom of the base. The lead connecting portions are oflset relative to the lead connecting portion of the stationary terminal which serves as a path for the wiping conductor to provide for ease in connecting the electrical leads. t

Each wiper mounted on the carrier engages an associated resistor, acting as a slide conductor to provide variable resistance values in response to movement of the carrier. The C-shaped portion of each of the carriers is provided with an elongated slot through which projects `one end of a control lever. The lever is provided with a I lever control to move the carriers ball member intermediate its ends, mounted in a socket formed vby a retainer plate and cover plate, the latter serving to secure the carrier members in position, and closing ott the top of the terminal housing. As the control lever is moved in its ball-and-socket joint, the free end disposed within the housing slides along the elongated slots in the carriers to cause coordinated or individual movement of the carriers and, hence, coordinated movement of the embodiment, the simplied design provides both a compact precision control for a plurality of resistors and may be manufactured and assembled at a relatively low cost. Other advantages will become apparent upon consideration of the objects and a escription of one preferred embodiment.

It is an object of this invention to provide a new and improved coordinated control for a plurality of resistors.

It is a further object of this invention to provide a coordinated control for a plurality of resistors which is inexpensive to manufacture and assemble.

lt is a. still further object of this invention to provide a coordinated control for a plurality of resistors having a novelly mounted pair of carrier members and single in coordinated relation to permit the selection of a desired coordinated resistance value.

It is a further object of this invention to provide a compact single lever coordinated control for a plurality of resistors which includes means to maintain the lever in the position of adjustment, as well as means to provide maximum angular adjustment.

Other objects in addition to those stated above will become apparent upon consideration of the following description and accompanying drawings wherein:

FIGURE l is a perspective view of the single lever coordinated control of the present invention;

FIGURE 2 is an enlarged exploded perspective view of the parts forming the coordinated control illustrated in FIGURE l;

FIGURE 3 is an enlarged top plan view of the coordinated control shown in FIGURES l and 2 with the cover' and retainer' plate removed and the control lever shown in cross section;

FIGURE 4 is a further enlarged cross-sectional View taken generally along the line 4`4 of FIGURE 3 with part of the control lever broken away;

FIGURE 5 is a cross-sectional view taken generally along the line 5-5 of FIGURE 3 with the control lever moved to a maximum angular position; and

FIGURE 6 is a bottom plan view on a reduced scale of the terminal housing.

Referring now to FIGURE 1, a single lever coordinated control is indicated generally at 10 in perspective and includes a housing indicated generally at l1 having an opening l2 of rectangular configuration in the top wall. A control lever 13 is mounted for nutating or joy stick movement within the housing 11 and functions to produce coordinated change in resistance values of at least two resistors, each of which is disposed Within the housing il at right angles to each other.

Referring now to the exploded perspective View of FIGURE 2, the parts forming the coordinated control are shown. The housing 1l includes a cover 14 of boxlike form which is tted into a terminal housing l5. The top wall of the cover i4 contains the rectangular opening l2 which was referred to in conjunction with the perspective view of FIGURE 1. The terminal base 15 includes side walls 20, 2l, 22 and 23, each having U-shaped notches 24, 25, 26 and 27 formed in the middle of the upper edge of each side wall. The terminal base 15 may be formed of any suitable non-conducting material, preferably from any suitable plastic having good dielectric properties such as nylon, lphenolformaldehyde resin, polystyrene or the like.

Resistor subassemblies, shown generally at 30, 31 and 32 are mounted in the terminal base 15 in a manner to be described. The resistor subassemblies are of similar design, each including a pair of spaced terminal contacts 33 and 34 having lead connecting portions 35 and 36 which extend through locating openings in the terminal base and are offset, as seen in FIGURES 3-6. The contacts 33 and 34 are joined to resistance elements '37, 38 and 39 by positioning between barbs 40 and 41 at the top of the respective element and an offset or shoulder causing a slight bowing of the rear part of the contacts. Thus, the resistance elements 37-39 are electrically connected to the contacts 33 and 34 by a mechanical joint as opposed to a soldered joint. Obviously, the latter is also acceptable, however, is usually avoided because of cost considerations.

Each of the resistors 37-39 may be of any desired type, such as a wire wound resistor, cermet type or the equivalent. While three such resistors are shown, it is obvious that a fourth may be mounted in a like manner along the wall 22. Similarly, each of the resistors shown schematically at 37, 38 and 39 may be compounded, that is, one may be positioned over the other, or in side-by-side relation. Similarly, the resistors may be increased in number and located at any desired angle to each other with a corresponding increase in the number of carriers, depending, of course, upon the number of circuits to be controlled in a coordinated manner. A common or electrically separate wiper may co-operate wit-h each resistor in each of the above cases.

Fixed terminals, illustrated at 42, 43 and 44, are associated with each of the resistors '30, 31 and 32, respectively. The terminals i2-44 are of identical design including a lead connecting portion 45 which projects through the terminal housing 15. A wiping or resistor contact pad 46 is formed at the upper part of the terminal and is of arcuate shape for reasons to become apparent. Transversely extending arms 47 and 48 are provided for mounting reception in vertical grooves `50, 51 and 52 formed in the side walls 20, 21 and 22 in the terminal housing 15.

The terminal housing 15 includes a bottom wall 54 provided with openings, such as that shown fragmentarily at 55 and through which the connecting lead ends of the terminals or conductors project when the parts are assembled. A vertical groove 56 is formed by an inwardly extending projection 81 which is integral with the side wall 20. The function and specific description of this construction will be described hereinafter in conjunction with FIGURES 3-5.

The coordinated control 10 further includes carriers 60 and 61 which are positioned at right angles to each other within the terminal housing 15. The carrier 60 includes a U-shaped body 62 having an elongated slot 63 formed along the base or bight of the U. Cylindrical bearing portions 64 and 65 are formed on the same axis and project from opposite yends of the U-shaped body, being adapted for reception in the axially aligned U-shaped notches 24 and 26 in the terminal base 15. The carrier 60 may also be formed of non-conducting material and, preferably, is formed of plastic such as those mentioned above to minimize friction during movement of the cylindrical bearings or trunnions `64 and 65 in the associated vslots 24 and 26. A conducting wiper member 66 is mounted on the carrier 60 for conducting co-operation with the resistor `31 and the xed terminal 43.

The carrier 61 is also of generally C-shaped or U-shaped form, being shallower in over-all depth than the carrier 60 and including a body portion 67 having vertical arms 68 and 69 at opposite ends. At the upper ends of the arms is provided cylindrical bearings or trunnions 7th and 71 for reception in the aligned U-shaped" notches 25 and 27 formed in the terminal housing 15. An elongated slot 72 is formed in the body portion 67 for co-operation with the control lever 13 in a manner to become apparent.

Mounted on each of the arms 68 and 69 is a conducting wiper 73 and 74, respectively. The Wipers `66, '73 and 74 are of similar construction and co-operate with the associated resistors and iixed terminals to provide a continuous electrical path from the resistor through the fixed terminal while permitting sliding or wiping contact movement for variance of the resistance values.

A retainer plate 75 is appropriately dimensioned to overlie the upper margins of the side walls Ztl-23 and includes a ball receiving socket 76 through which the control lever 13 projects. A ball 77 is formed intermediate the ends of the control lever 13 and is received in the socket 76 with a bearing fit. A friction washer 78 may be positioned over the control lever 13 intermediate the socket 76 and ball '77 to increase the drag on the control lever and thereby preclude inadvertent movement. The friction washer '7-8 may be formed of felt or the like and also seals the space between the opening 12 and lever 13, excluding dust or other foreign material which could impair the operating quality and efficiency of the control. When assembled, as seen in FIGURES 4 and 5, the cover 14 is positioned over the retainer plate with the control lever 13 projecting through the polygonal opening 12 to complete the coordinated control.

As seen in the plan view of FlGURE 3, a projection Sii is formed in the corner formed by the intersection of the walls 2t) and 21. Except for being opposite-handed, the projection 80 is of a design similar to the projection 81 which forms the groove 56. The projection 80 forms the grooves 82 and 83 while the projection 81 forms the vertical groove 56 and a second groove 84 at right angles to the groove 56.

The resistor subassembly 31 is inserted with the opposite ends of the resistor 38 slidably received in the grooves 56 and 82 while the ends of the bowed portions of the contacts 33 and 34 engage the side wall 20 to hold the resistor rigidly fixed against the inner wall of the groove and the barbs 40 and 41 in tight contact with the associated resistor.

As the resistor subassembly 31 is inserted, the lead portions 35 and 36 of the conductors 33 and 34 pass through openings 55 and 85, respectively, formed in the bottom wall 54 of the terminal housing 15. It can be appreciated that the resistor subassembly, which is mechanically joined together in the fashion shown in FIG- URE 2, and may be easily inserted in the housing 15 by pressing into position within the associated grooves Without necessitating further means to locate or hold the same in operative position. Similar projections 85 and 86 are carried at the other corners of the terminal housing 15 and form grooves 87 and 88 which co-operate with the resistor subassemblies 36 and 32 to locate the same in a fashion similar to that described with respect to the resistor subassembly 31.

Prior to installation of the resistors, the fixed contacts #t2-44 are installed, then the resistor sub assemblies, and then the carriers 60 and 61 in this order. The wipers on each of the carriers are of similar design which may be appreciated from comparision of the cross-sectional view of FIGURES 4 and 5. The wiper 66 includes a dimpleforming movable wiper portion 90 which slides across the face of the resistor 38 while an arcuate portion 91 is shaped to engage the arcuate pad 46 on the lixed terminal 43 to provide a continuous path for electrical power. Since the wiping conductor 66 is mounted on the carrier 60, any movement of the carrier will change the position of the wiping portion 90 across the base of the resistor 38 thereby changing the resistance value in a E manner well known. The wiping conductors 73 and 74 are of similar shape to the wiper 66, however, include a longer arm at the upper margin for engagement with the arcuate pad. The arm is of increased length to compensate for the reduced length of the body 67 of the carrier 61.

As is apparent in the views of FIGURES 3, 4 and 5, the axes about which the carriers rotate lie in the same plane and'intersect at right angles to each other. These axes also are coincident with the center of the sphere or ball 77 on the control lever 13. This maximizes the carrier movement while keeping the depth or thickness of the control at a minimum. It can be appreciated that movement of the lever 13 causes coordinated movement of the wipers on the respective carriers to cause a change in the resistance value.

As shown in FIGURE 5, the control lever 13 may be moved from side to side without affecting the resistance value set on the other carrier. For example, the inner end of the control lever 13 is free to move in the elongated slot 63 without affecting the position of the carrier 6i), regardless of its position. Similarly, the inner end of the control lever 13 is free to move in the elongated slot 72 without affecting the position of the carrier 61. When the control lever 13 is moved in a direction other than along the X axis or Y axis, which axes are formed by the rotational axes of the carriers 60` and 61, respectively, the carriers move in a coordinated path, dictated by the path of movement of the inner end of the lever 13. Accordingly, each of the wipers on the carriers will shift along the associated resistor to change the resistance value. As noted above, a fourth resistor may be added along the side wall 22, being mounted in the same manner as the resistor subassembly 31.

As noted briefly above, the number of resistors controlled may be increased by positioning one resistor over the other, or in side-by-side relation. Within the inventive concept set forth above, it is contemplated that the housing can be made polygonal in shape, for example, hexagonal with three carriers mounted in the oppositely facing side walls and movable to vary resistors mounted along the side walls in the coordinated fashion described above for a lesser number of resistors. These and similar modifications are considered to be well within the scope of this invention.

It can be appreciated that the coordinated control of the present invention is compact and relatively inexpensive to manufacture and assemble because of its novel simplified construction. The cover 14 may be joined to the base by staking the lower margin of the cover over the bottom of the terminal base or the equivalent. Mounting lugs or ears may be provided on the cover 14 or terminal housing 15 depending upon the particular intended use.

Some of the typical uses of the coordinated control of the present invention are to control resistors in vertical and horizontal centering circuits of an oscilloscope, base and treble control of an audio system, volume and contour control in an audio system, speaker phasing, black and white contrast for television receivers and hue and saturation control on color television. Other uses are focus and astigmatism controls on an oscilloscope.

Upon a consideration of the foregoing, it will become obvious to those skilled in the art that various modifications may be made without departing from the invention embodied herein. Therefore, only such limitations should be imposed as are indicated by the spirit and scope of the appended claims.

I claim:

1. A coordinated control for a plurality of resistors comprising a housing having at least two pairs of opposing side walls, a control lever, ball-and-socket means mounting said control lever in said housing for nutating movement about a point intermediate its ends with one of said ends positioned within said housing and the other of said ends disposed outside of said housing for manual engagement, said point being coincident with the center of said ball, a first carrier formed of a non-conducting material and pivotally mounted on a first axis in said housing, said carrier having an elongated slot therein for receiving said one end of said control lever, a second carrier formed of non-conducting material and being pivotally mounted on a second axis in said housing, said second carrier having an elongated slot therein for receiving said end of said Icontrol lever, said first and second axes being disposed at an angle to each other whereby movement of said control lever causes said end to move in said elongated slots and each of said carriers to cause co-ordinated movement thereof, slide conductor means mounted on at least one end of each of said carriers, at least two resistors mounted in said housing at said one end of said carriers for wiping engagement by each of said slide conductor means, and a fixed conductor wipingly engaged by a part of ea-ch of said slide conductors to form a fixed electrical path from said movable slide conductor on each of said resistors.

2. The coordinated control of claim 1 housing includes a terminal housing and a retainer plate, and said pivotal mounting of each of said carriers consists of a U-shaped notch formed in an upper margin of opposite side walls of said terminal base, each of said carriers having cylindrical end portions received in said notch and held therein by said retainer plate overlying the open end of said notch.

3. The coordinated control of claim 2 wherein said housing includes a cover, said cover having an opening through which said control lever projects, said cover and said retainer plate forming a socket for mounting said ball on said control lever.

4. The coordinated control of claim 3 wherein friction means is interposed between said cover and said retainer plate to provide drag on said ball and prevent unintentional movement of said -control lever.

5. The coordinated control of claim 3 wherein substantially all of said ball is disposed below said cover and said opening is of polygonal shape to permit maximum angular movement of said control lever.

6. The coordinated control of claim 1 wherein said terminal housing is provided with a pair of spaced projections forming vertical grooves along a wall portion thereof, a side portion of each of said vertical grooves overlying an end portion of each of said resistors for fixed positioning thereof relative to said carrier mounting said slide conductor means whereby said slide conductor means is positioned for movement relative to said resistor in response to movement of said control lever.

7. The coordinated control of claim 6 wherein each of said resistors is provided with electrical contacts at opposite ends thereof, each of said contacts having a lead portion thereon for connection with a conductor, said lead portion extending through a bottom wall portion of said terminal base and projecting therefrom to permit easy assembly of said resistor into said terminal base and electrical connection thereto.

8. The coordinated control of claim 7 wherein each of said electrical contacts includes a bowed portion for engaging a sidewall of said housing to urge said resistors against said vertical grooves.

9. A coordinated control for a plurality of resistors comprising a housing having at least two pairs of opposing walls, a control lever, ball-and-socket means mounting said control lever in said housing for nutating movement about a point intermediate its ends with one of said ends positioned Within said housing and the other of said ends disposed outside of said housing for manual engagement, said point being coincident with the center of said ball, a first carrier formed of a non-conducting material and pivotally mounted in U-shaped notches in one pair of opposed side walls in said housing, said carrier having an elongated slot therein for receiving said one end of said control lever, a second carrier formed of non-conducting wherein said material and being pivotally mounted in `Ushaped notches in the other pair of opposed side walls in said housing, said second carrier having an elongated slot therein for receiving said end of said Ieontrol lever, a retainer plate overlying said U-shaped notches in said side walls to confine said carriers therein for pivoting movement, said rst and second axes being disposed at an angle to each other whereby movement of said control lever in said ball and socket means causes said end to move in said elongated slots in each of said carriers t0 cause coordinated pivoting movement thereof, slide conductor means mounted on at least one end of each of said carriers, at least two resistors mounted in said housing at said one end of said carriers for wiping engagement by each of said slide conductor means, a fixed conductor wipingly engaged by a part of each of said slide conductors to form a lixed electrical path from said movable slide conductor on each of said resistors.

References Cited UNITED STATES PATENTS 7/1958 Dalgleish et al 338128 3/ 1967 Jonsson 20G-6

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