US1618015A - Rheostat - Google Patents

Description

,Patented Feb." 15, 1927.

WILLIAM K'ArsLINceor omesso, rLLrNois, AssreNoR To KnLLoGG swrroHBoAnn 1,618,015 PATENT. oFFICE.

AND SUPPLY' COMPANY, 0F CHICAGQILLINOIS, A CORPORATION OF ILLINOIS.

RHEOSTAT.

Application iiled October 8, 1923. Serial No. 667,093.

fr '.-My invention relates to rheostats for varying the-`resistance in lan electric circuit Y,and is adapted particularly foruse in controlling thev4 filament of. electron tubes and ianobje/ctof my invention is to provide a vrheostat which is simple in construction but very durablev land etiicient. n

Rheostats of the type employed in use for "controlling the current iiow through the filament `oi an electron tube are usually provided ywith a contact wiper and when the rheostat is operated to increase or decrease the amountof resistance in the circuit in whichthe'rheostat is used, this increase or decrease in the amount of resistance is eifyf ected .by avcomplete turn ci the convoluti'ons-of vthey resistance coil. This'means oi adjustment is objectionable in that it is dii- 'cult in some instances to obtain the proper Vamount ofresistance in the operating circuit. To overcome this objectionable feature I havev designed an improved rheostat and a l 'feature of'my invention vis the provision of "a vernier-attachment in the form of a single rt-urn' of wirel'equal'to several turns of the 'fmarn resistance element) in series relation with the resistance coilv of the rheostat and an 1 auxiliaryl wiper associated therewith.

Another` `feature of my invention is the method offcontrolling the movement of the wiper associated with the Vernier turn of wire to place the same in contact therewith,

and the movement or" the wiperassociated with the main resistance coil. The movement of the wiper of the resistance coil and 1 Iwiper ofthe vernier wire is under the con- ',trol of a singleunit, which vafter having been moved a certain degree may be rotated in either direction a limited distance without effect-ing the movement of the Wiper associa-ted with the main resistance coil and bring about the movement ofthe wiper as- 2 sociatedwith thevernier wire to further in- 1 crease orfdecrease the resistance.

suing speciiication, `and for a more complete j understanding'ot the same, reference mayY 'lfbe lhad to Athe accompanying drawing, v'1n .which like reference characters in the sev.-

i l'eral views .denote like parts and in which;

; Another lfeature of my invention is theV F 1 is a front view of the rheostat ot my invention illustrating it in Lits normal or oil position.

Fig. 2,is a right side view of Fig. l;

Fig. 8 'is a sectional view along the line 8 3 ot Fig. l;

Fig. Ll is a back plan'view of the rheostat;

Fig. 5 is a sectional view along the` line 5 5 of Fig. 2, and

Fig. 6 is a view similar to Fig. 5 but showing the rheostat in its olf normal or on position.

Referring now more in detail to my invention as illustrated in the accompanying drawing, the rheostat of my invention comprises a resistance coil or unit 2 of a predetermined ohmic resistanceV wound upon a iiat strip o'i' insulating material 3, by suitable machine means, its ends 6 and '7 passing through suitable orifices in the strip 3 for holding purposes. The strip 3 which carries the resistance coil 2 after being wound is now formed intoV a substantially ring shaped member R by means of a suitable torming operation and its ends 6 andv 7 are then secured to an arcuate shaped yoke iember 8 by means of the screws 9 and 10. rfhe screw 9 passes through a suitable oriiice in the end 6 of the member .R and eX- tends through the yolre 8 but insulated therefrom by means oi an insulating bushing 11, and a nut 12 having screw threaded engagement with the screw 9 secures the end 6 to the yoke 8. One end 4 of the resistance coil 2 is securet to the screw 9 and a terminal 13 resting between-the nut 12 and bushing 11 provides connecting' means to theA resistance coil or unit 2. The screw passes through suitable oriiices in lthe end 7 oi the member R and yoke 8 but .insulated from the yolre 8 by anv insulating bushing 14, and a nut 15 having screw threaded engagement with screw 10 secures the end 7 of the member R to the yoke 8. A terminal 16 rests between the bushing 11i and the nut- 15 for the usual connection means. K

The arcuate yoke member 8 is provided with a pair ot integrally formed depending arms 17 and 18 substantially; parallel with each other Vfor supporting the rotatable shaft 19.' l' provide a U shaped wiper member B which rests between-the arms 17 and 18 and itswiper arms 2O and 21 engage re- `19 extending through the V32as a whole is secured to the arm 1S of t spectivelyv the peripheral portions of the convolutions of the resistance unit 2 and are formed to provide a spring effect for gripping the convolutions of the coil 2 so as to insure a good contactual engagement between the wiper arms 20 and 21 and the convolutions of the coil. yThe bridge 41 of the U shaped wiper member B is provided with a longitudinal slot 42 and a screw 43 having screw threaded engagement with the shaft slot 42and effects the rotation of the wiper member B as will present-ly be. described. rlfhe rotatable shaft 19 is provided with a reduced portion 19 which passes through suitable orifices 26 and 27 .in the arm 17 of the yoke 3 and wiper varm 2O ofthe wiper member B and orifices 28 and 29 of the wiper arm 21 of the wiper inemher B and Varm 13 of the yoke member The vernier unit V of the rheostat of my invention comprises a disc 30 of suitable msulating material and secured to its face near its peripheral edge is a turn of wire 32,

.its one end ,passing through a suitable orifice in the disc 30aiid bent to secure the same to the disc 30. The other end also passes through an orifice in the disc 30 and is in turn soldered to the terminal 15 for purpose. as will presently be described. Intermediate ofthe ends of the wire 32 the said wire rests in a slot of a pin 33 to hold the same against the disc 30 and also maintain its circular shape. The disc 30 and its wire il() yoke member 8 by means of a screw 35 which screw has screw threaded engagement with. a suitable tapped orifice in the arm 13. 1 also provide a- Wiper 36 which is adapted to contact with the wire 32 the said wiper being secured to a lug 37, which lug 37 is provided with a central orifice 38. The disc 30 is provided with a central orifice 39 through which the reduced portion 19 of the shaft 19 protrudes and is of a size to permit the lug 37 and its wiper 36 to be slipped over the shaft portion 19 as a whole and secured thereto by means of the set screw 40. The shoulder formed by the reduced portion of theshaft 19 rests against the face of the arm 17 of the yoke S and the lug 37 to which the wiper 36 is secured is fastened to the shaft 19 to prevent lateral movement of the shaft 19 but permits its rotation. A. knob K is supported on the shaft 19 for rotating the same and for a detailed description of the method of supporting the knob refeence may be had to an application of Emil J. Nielsen, Serial No. 603,927 tiled Nov-cmber 29, 1922.

1 `lVl1en the wiper arms 20 and 21 of the wiper member B associated with the resistance unit 2 and the wiper 36 associated with the vernier resistance unit V are in their ofi' or normalposition lthey are in the position as clearly illustrated in Figs. 1, 4tV and 5, To

operate they rheostat of my invention the knob K is grasped and rotated in a clockwisedirection with reference to Figs. 1, 5

and 6 causing the shaft 19 to-be rotatedand as thewiper` 36 of the Vernier unit V is se- 70 cured to the shaft 19 by means of the set screw 40 itI is also rotated causing it to contact with its vernier resistance 32. The U shaped wiper member B is not rotated as it is loose on the shaft 19 and the first movenient of the shaft 19 from its off position only effects the travel of the wiper 36 of the vernici* unit V and the degree of travel of the wiper 36 before the wiper member B is rotated is governed by the length of the slot 42 in the bridge 41 of the wiper member B. Now as the shaft 19 continues rotating the screw 43r secured to it rotates through a predetermined degree of rotation governed by the length of theslot 42 before the movement of the wiper arms 20 and 21 is brought about. 1n the rheostat of my invention the shaft 19 travels through approximately ninety degrees of rotation before the screw 43 which extends through the slot 42 engages the edge 4 4 of the slot 42 in the bridge 41 of the wiper member' B as clearly villustrated in Fig. 6. The further rotation of the shaft' 19Y now brings about the rotation of the wip-er member B causing the wiper arms 2() and 21 thereof to engage the convolutions of the resistance unit 2, the Wiper 36 of the vernici' unit V being also rotated. lVhcn the knob K is rotated in a clockwise direction the wiper varms 20 and 21 engage successive convolutions of the resistance unit 2,

causing the resistance of the electrical circuit inwhich the rhecstat is used to he dccreased and when the proper coarse adjustment is obtained, a finer adjustment may be obtained by the use of the vernici' unit V of the rheostat of my invention.

From the above description it may be seen that the wiper 36 of the vernici: unit V is approximately ninety degrees in advance of the wiper arms 20 and 21 of. the wiper member B associated with the resistance unit 2 as the shaft 19 is rotated from its oii' position before the wiper member B is moved 'to engage the first convolutions of the resistance unit 2. Thus as the wiper member B is moved from its off position to its extreme on position iu which position practically all of the resistance unit f2 is out out the wiper member B has traveled through ap- FLW? proximately two hundred and seventv de- `grees of rotation and as the wiper of the i' trontubethere isa critical'point atwhich c theitube will work at itsma-Ximum efliciency .Cency i :N'Ow has been'ladJusted as above described to yflfp'lace the wiper arms 20a-nd. 21 in position cutv'in OI'Out obtain this maximun'i ei'ii- 'when the rheostat of my invention 'onfthe resistance unit 2 so". that the approxifmateamouiitiof resistance has been cut in vthe circuit I provide'the Vernier unit V whereby the further rotation'of the wiper 36 of thevernier unitVv 'may bev rotated in a counter clockwise or clockwise direction to .further increase Ior decrease the resistance untilrjust thenriolit amount of resistance is ucutin the circuit as will now be described, v'After the wiperarms. 2O Aand 21 have been adjusted to approximately out in the proper amount of resistance of the unit 2 after having' rotatedr the `'shaft' 19 in a clockwise direction, the knob K may -now be rotated in v.a counter clockwise direction through approXimately ninety degrees of rotation withoutfdistiirbing lthe ladjustment of the wiper @arms 20.*and 21 ofthe wiperY member B as the Wiper member islooseup'on the shaft 19 and ,a'sfthey wiper36oftheVernier unit is lined to thej'shaftjl)4 this counter' clockwise rotation of the shaft 19 causes the wiper to rot-ate in thisfdirection andY wipe over the .wire 32 of the Vernier unit V. The distance traveled by the Ywiper 3G vover the wire inr its counter clockwise direction through itsfninetyldegrees of 'rotation may beapf Lproximately"the lengtlifof one or two conis moved over the wire 32 in this counter clockwisedirect-ion it A may be placed in an i infinite number of positions oiithat portion ofytfhe wire 32 that is covered by the wiper 1 45'l grecsV of counter clockwise rotation.

36 in its course" ofl travelin its ninety dey lt is .i also "readilyapparent that the wiper 36 of k the vernier unit V may be rotated in either axcloclrwise or counter clockwise direction in this ninety degreesv without disturbing the fadjustinent of the wiper arms 2O and 21 of the/wipermeinber B'that is in its adjusted position.

If vin rot-ating the wiperginember D i) lS "farms and 21 are rotated beyond the approximate pointfof the proper amount of resistance to be used', the knob K is turned in a counter clockwise direction causing the shaft'19 to also rotate in a counter clockwise direction until the screw L13 securedto the shaft the wiper 36of the Vernier unit V also travels in this direction. Further rotation of the shaft 19 in this Vdirection after the screw 43 has engaged the edge 45 ofthe slot l2 causes the wiper member B to be' rotated in a counter clockwise direction causing the wiper arms to enga-gesuccessive convolutions of the resistance unitj2 until the approxi-' mate amount of resistance is cut in and to obtain a finer adjustmentthe Shaft may vnow be rotated in a vclockwise direction through ninety degrees of rotation to permit f the wiper 36 of t-hev Vernier unit V to be rotated over the portion of the wire 32 Ycovered by the degree of rotation of the vwiper 36, f A

also provide means for holding Ythe wiper arms 2O and 21 in their adjusted'position and to insure good electrical contact, as will now be described. The face of eaclifwipei" arm 20 and 21 is provided with an integrally formed tongue portion 46 which projects slightly above the face of each4 arm 2O and 21 :io that when the wiperl member B is inserted between the, arms 17 and 18 ofthe yokeV ber B is in position engage the inner faces of the arms l? and 18 thus producing frictional holding means for holdingthe wiper arms 2G and 21in their adjustedpositionand for insuring good electrical cont-act, The wiper 3S of the vernier unit Vis also provided with a frictional holding means for lholding the wiper 36 in itsadj usted position.` The wiper 36 is vprovided with an integrally formed arm L18, diametrically opposite it and when the wiper 36 is secured in posit-ion on the shaft 19V the arm l8'engages the face of the disc and the tension ofthe arm 48 is Asuch as to produce frictional holding means between the arm li8 and face of the disc 30 to hold the wiper 3G in any of its adjusted positions, and to o bviatc a side thrust on the shaftof the device. lThe two' arms insure good electrical contact of the wiper on wire 32 Vand at the same time prevents a sido thrust on the shaft.V The wiper member B is limited in its oifposition by means of the screw 35V which secured thedisc 31 to the arm 18 of the yoke 8; This screwwprojects through the arm 18 and Yis engagedfby the i wiper arm21 when the wiper member B is moved to its oftposition to limit its movement in that direction.` T he wiper arm 21 also engages the screw 35 when the wiper member B is moved its extreme on position to limit the movement of the wiper member B in this direction, thus the screw 35 which secures the disc 31 in position on the arm 18 of the yoke 8 also serves as a stop for the wiper membei'B. A

In Fig. Y.3 l illustrate the ilieost-aty mounted upon a panel sliown'in dotted lines by means of a screw 51 whichY extends through a' suitable orifice in the panel and has screw threaded engagement with a suitable tapped rio orifice 52 inthe arm 17 of the yoke member 8.

From the foregoing it is apparent that my device is so arranged that by simply turning the control knob the turns o-f wire on the main rheostat maybe cut in or out and by a movement of the same knob the vernier wiper may be madeto move over its turn of wire for the fine adjustment.

While I have described a preferred embodiment of my invention it ist-o be understood that'I do not wish tobe limited to the'exact structure as shown and described, as changes will readily suggest themselves, and I therefore aim to cover all such changes and modifications as come within the spirit and scope of the appended claims. Y

What I claim as new and desire to secure by United States Letters Patent, is as follows l. A device'of the character described including a supporting yoke, aresistance unit supported by said yoke, a wiper operatively associated with said resistance unit, a shaft for rotating said wiper, a second resistance unit supported by said yoke, and a wiper opera-tively associated with said second unit, a shaft for adjusting said wipers, said lirst wiper having integrally formed means consisting of a tongue member adapted to engage saidsupporting yoke to maintain the same in any adjusted position, said second wiper having integrally formed means consisting of an extending portion adapted to yengage a supporting member to maintain the same in any adjusted position, and control means permitting the rotation of the wiper of said second resistance unit by said shaft from its adjusted position without affecting the adjustedV position ofthe wiper of said first unit.

2. A device of the. character described including va supporting yoke, a resistance unit supported by said yoke and a wiper associated therewith, Ya second resistance unit supported by said vyoke and a wiper associated therewith, a shaft for advancing said wipers into engagement with their respective resistance units, said iirst wiper having integrally formed means `consisting of a tongue portion adapted to engage the said yoke member to maintain the .said wiper in any adjusted position, and control means to permit the movement of said second wiper in a clockwise direction or counter clockwise direction a predetermined degree without affecting the rotation of said iirst wiper.

3. .A device of thejcharacter described including a rotary shaft, a mounting member supporting said shaft, a pair of resistance elements directly supported by said mounting member, a pair of contact elements for contacting with said resistance elements, one of said contact members being directly connected to said shaft, and the other `member being loosely supported thereby so that the first contact member mav be moved a predetermined distance without moving said second contact member, one of said contact inembers having integrally formed means consisting of a tongue portion adapted to engage said mounting member to maintain said wiper in any adjusted position, said other contact member having integrallv formed means consisting of an extending portion adapted to engage said mounting member to maintain said wiper in any adjusted position.

4. A device of the character described including a mounting member, a pair of relatively stationaryresistance elements connected to said mounting member, a rotary shaft supported by said mounting member, a double wiper for engaging one of said resistance elements and a single contact 35 said single contact wiper in any adjusted position.

5. A device of the character described including a plate of insulating material, a resistance element connected thereto, a double ended wiper having its one end adapted to engage said resistance element and its other end adapted to engage said plate of insulation to provide frictional means to maintain the wiper in said engagement with said resistance element, and a member for moving said wiper over said resist-ance element.

6. A device of the character described including a mounting member, a resistance element supported thereby, a rotary shaft supported by said mounting member, a wiper having a slot, a member extending through said shaft into said slot whereby the shaft may be rotated a predetermined distance while permitting the wiper to remain Stationary and yielding contact means consisting of an integrally formed tongue portion adapted to co-act between said wiper and said mounting plate to maintain the wiper in any position to which it is rotated.

Signed by me at Chicago, in the county Cook and State of Illinois, this 4th day of Getober, 1923.

IVILLIAM KAISLING.

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