Патент USA US2127083код для вставки
Aug. 16, 1938. I . ' ’ K. HOWE ‘ RHEOSTAT ' Filed Nov. 13, 1935 .24 2,127,083 2 Sheets-Sheet 1 A ‘ATTORNEY \ 2 2,127,083 On the inner face of the plate I and surround~ ing the bearing and engaging the flange Ilia is an insulating disk I2. The outer portion and rear 5 face of this disk is cut away to form a seat for a metal collector ring l3 which has a strip 130, extending outwardly therefrom to a terminal connection 80. mounted in the terminal block 1. A conducting wire or strip i3b connects the termi nal 8a to one of the terminals 6, as shown in Fig. 1, for use as a series connected rheostat. The rheostat is readily adapted for use as a potentiometer by omitting the conducting strip . I31; and replacing the terminal connection to by a third terminal like the terminals 6. The contact arm Id of the rheostat is in the 24 form of a flat plate having outwardly bent sides. Lda and has a large central opening to receive an insulating block l5 which is located between the sides Ila of the contact arm. The block if: has an inwardly projecting circular portion which projects within the central opening of the contact arm and this inwardly projecting por tion i5a of the block is cut with concentric spaces as indicated in Fig. 2 for increasing the surface leakage distance. A lug Hb is upset from a central portion of the contact arm and engages a hole in the inner face of the block IS. The insulating block and contact arm are thus held in fixed relationship to each other, by the side portions Ila which embrace the sides of the block and the lug Nb which prevents relative longi tudinal movement. The contact arm extends outwardly at one end and has a depressed por tion Me for engaging the series of contacts 3 successively as the arm is turned. The opposite end of the contact arm has another depressed portion lld as shown in Fig. 2 which engages the collector ring I! on the opposite side of the shaft from the engagement of the other end of the contact arm which engages the contacts 3. The contact arm is rigid throughout all parts and of good conductive material such as hard cop per. In rheostats,. where double concentric, rows of resistor contacts I are used, the contact arm may have depressed portions He at its opposite ends for engaging the two series of contacts. The central portion of the insulating block I5 is provided with an enlarged circular cavity in which is seated a spiral spring i6 which encircles the bushing It and serves to impose pressure to force the block l5 and contact arm inwardly so that the contact arm always engages the con tacts 3 and the collector ring i3 with su?lcient pressure to maintain a desirable electrical con tact at all times and in all positions. The spring is thus insulated in such a way that it cannot carry current and by reason thereof it is not sub jected to heating currents which might reduce its tensionr Moreover, by reason of the contact am 60 making engagement with contacts at its opposite ends and by reason of receiving the spring pres sure at its central portion, the pressure imposed upon the contacting portions is always balanced and approximately equalized in any position of - the contact arm. In cases where the contact arm has oppositely extending portions of pro nounced difference in length, thespring ii, in stead of encircling the shaft. may be located to one side thereof and thereby apply the spring pressure to a more central portion of the con tact arm. Also, the spring may be of other form‘ than spiral and supported in any suitable man ner. . The shaft ll of the rheostat extends through the bushing and is threaded at its opposite ends as shown in Figs.'2 and 4 and is likewise slotted at its opposite ends for providing a locking en~ gagement of the parts without the necessity of usingset screws. For the purpose of holding the spring IS in position and imposing pressure ‘thereon and for locking the movable contact arm and block IE to the shaft, a perforated plate i8 is slid over the inner end of the shaft and seats itself against the spring and between two outwardly extending side portions i5b of the ill insulating block. The plate l8 has two inwardly v projecting lugs I'o‘a on opposite sides of its cen tral opening which project into the slot at the end of the shafti'i. Thus the plate i8 is locked to the shaft which plate in turn locks the in sulating block and the contact arm to the shaft. Turning of, the shaft will therefore result in turning the contact arm to any position desired. A washer is having lugs I9a which project into the slot in the end of the shaft, is located on the outer face of the plate 18 and the parts are locked in position by the end nut 20 on the inner end of the operating shaft. The use of set screws is thus avoided and also the ?xed position of the contact arm and insulating block in relation to the operating shaft is insured and maintained without any chance of the parts working loose. A sheet metal cover plate 20, which may some times be in the form of a skeletonized frame, is mounted on the back of the rheostat and has 30 an inwardly bent rim 20a which is offset at 20b and fits within the rim la of the main rheostat plate and is cut away to fit over and bent to partially cover the terminal block ‘i. A saddle 2_i with inward projections at its ends, embraces the 35 rim of the plate i and the offset portion 20b of the cover plate and is held in place by a screw 22 which has a threaded engagement with the rim of the plate I. Any number of these clips or clamps may be used, three being shown in the drawings spaced apart from each other around the periphery of the rheostat, for holding the cover in place; and supporting feet 23 may also be used as desired for mounting ‘the rheostat in place. These supports 23 may be held in place by the screws 22 on the outside of the saddles 2|, the saddles 2| being provided with outwardly extending bent edges 2la for maintaining the supports 23 in fixed position in relation thereto. The supports for the rheostat may be variously 50 arranged to suit the particular requirements and may readily be mounted in multiple and like wise the shafts in a number of rheostats may be coupled together for multiple control. The cover plate 20 has a series of separated cir cular slots 200, as shown in Fig. 3 and on the inside of the cover plate is another circular plate "(I which is rotatably secured to the cover plate 20 by aneyelet 208. The plate 20d is large enough to extend beyond the holes 200 of the 60 cover and affords means ‘for providing an ad justable stop for the contact arm at any desired intermediate position. A screw 20f passes through any desired one 01' the openings 20c and through the plate 20d and 65 engages a U-shaped angle piece 200, as shown in Figs. 2 and 3. By loosing the screw 20! the posi~ ‘ tion of this angle piece may be adjusted as de sired through the range of any one slot 20c and by transferring the screw to another slot 200, 70 the range of adjustment may be extended to any portion of the cover plate. The plate 18 is pro vided with an extension "b at one end and has an outwardly.v bent end Hie-which is adapted to engage thestop 20a in its adjusted position. This 75 am'noss auxiliary stop is desirable in cases where a pre determined lirnit of adjustment is ?xed for the control of any particular apparatus and the stop 200 is adjusted to such position that the arm no will engage the same at the limiting predeter mined position. In order to obtain continuous adjustment of the stop 20g over all portions of the contact arm travel, the piece 200 is provided with two circumferentially spaced tapped holes 10 20h for receiving the screw 20/.” when the limit of adjustment in one of the slots No is reached, the screw "I may be transferred to the other hole ilhiwhich permits adjustment throughout the space occupied by the portions of the cover 3 ing shaft when adjusting the rheostat to different positions, the‘application of such force is applied to the shaft at a portion'immediately adjacent to the pointer or "disk 24, and when the latter. strikes the stop lb on either side thereof, there 5 are no undue strains imposed upon the operating parts because the stop acts to oppose further movementof the shaft beyond its limiting posi tions in substantially the same plane as the ap plication of the force for turning the shaft. It is apparent that the operating parts of the rheo stat may be quickly and conveniently assembled and disassembled owing to the simplicity of rela tionship and relatively small number. of parts. 20 between the slots "c. The U-shaped piece I It is also evident that the structure is sturdy and 209' may also be utilized for locking the contact dependable in long continued use without like arm assembly in any ?xed position desired. The lihood of the parts working loose or being dis Li-shaped piece 2001s of such dimensions that its placed from their proper relative positions. Also, extending portions may embrace the projection by reason of the rigid structure of the contact arm throughout and its balanced application of 20 20 Me of the plate II. For locking the parts in any 15 desired fixed position of ‘ adjustment. the U contact pressure, the maintenance of good elec- . shaped piece is placed to enclose projection lie and the U-shaped piece is then fastened by its trical contact at all times and in all positions of screw 20! to remain in any desired position. The operating handle and the part which 120-‘ Although a preferred form of the invention has been described, the same may be applied in 25 operates with the main stop lb for limiting the rotation of the operating shaft at the resistance all out position and the resistance all in position, are mounted on the front end of the operating 30 shaft close to each other. In front of the washer 9 on the shaft I1 is mounted a thrust washer 9b, the rheostat is assured. ‘ various features thereof to other forms of rheo- . stats than the particular type shown, and-to a wide range of rheostats of different capacities; also various modifications may be made therein without departing from the scope of the inven 80 tion. a The invention claimed is: as shown in Figs. 2 and _4. In front of this wash er is mounted a plate 24 having a pointer 24a. 1. A rheostat comprising a rotatable shaft, a contact arm operated by said shaft, 8. stop mount 'Iv'his pointer also serves the function of coop erating with the main stop lb at the extreme lim ed on the‘ face of the rheostat, a pointer having iting positions of the contact arm. Within the a portion“ extending within an opening of said central opening of this plate or pointer projects shaft and adapted to engage said stop, a plate having a portion extending within an opening of a pair of oppositely disposed lugs 24b which en gage the slot in the front end oi’ the operating said shaft andhaving oppositely bent portions, operating means for rotating said shaft mounted 40 shaft i'l. Thus there is no opportunity for this pointer to work loose or change its position rel ‘on said oppositely bent portions and spaced atively to the shaft i1. ’ thereby from the end of said shaft, and means In front of the pointer on the shaft is mounted for holding said pointer and said plate in posi ' a metal strip or yoke 25 which extends across the tion on said shaft. 2. A rheostat comprising a plate, a rotatable face of the plate 24 and fits over the shaft and is provided with a pair of lugs Zia which extend . shaft, a contact arm operated by said shaft, a into the slot at the front end of the operating stop disc having a portion encircling said shaft and located on the front of the plate of the shaft. It is thus locked to the shaft and main tained in position relatively thereto. The strip rheostat, and a bearing sleeve for the shaft ex 25 is bent forwardly at its ends and again bent tending through the plate of the rheostat and inwardly at its ends to form can 251; as shown having a‘ ?ange engaging one side of the plate in Fig. 4. A nut 20 is screwed on the front end of the rheostat and also having a portion bent of the shaft I‘! to hold the parts in position on over and in front of said encircling portion of the shaft as regards any longitudinal movement the stop disc for holding said sleeve in fixed posi tion on said plate and for likewise holding said thereon. The handle 21 is of a general cylin drical form with scored out central portion. It stop disc in fixed position with reference to said, plate. . is provided with a pair of longitudinally extend 3. A rheostat comprising a plate carrying‘hxed lng holes at opposite sides through which extend hexagonal rods 20. The inner ends of these ' contacts, a sleeve ?xed to said plate, a shaft jour 60 rods have reduced portions Ila which are' nalied in said sleeve, an insulating block rotat threaded and engage threaded holes in the ears ably and slidably mounted'on said sleeve, a rigid 25b. When these rods are screwed into place as contact arm coupled with said block and rotat shown in Fig. 4, the shoulders of the rods at the ably driven by said block, a plate fixed to said threaded ends seat against the faces of the ears shaft to turn therewith, said last named plate ,' Zilb and thus form rigid supports for securing the having a locking driving connection with said handle in fixed position. The outer ends of these . block for rotating the same while permitting rods have threaded openings which are engaged relative axial movement‘ thereof, and a spring by screw bolts 29. A circular, face plate or name plate 3| covers the main portion of the outer 70 end of the handle 21 and is located between the 35 40 45 60 ‘ 55 60 65 seated be ween said block and said last named plate to c use said block to impose pressure'on saidarmtomaintainsaidarmincontactwith head of the screw bolts 2| and the outer ends of - said ?xed contacts.’ ' the rods 2: and thus serves to hold the. handle 4. YA rheostat comm an“, H i I in fixed position on the yoke v2i. contacts, a sleeve fixed to said plate, a'shaft jour c In operation it will be evident am when‘ force ' nallcd in said sleeve, an insulating block rotatably 75 is applied to the yoke II for turning the operat and 's‘lidably mounted on said sleeve, a rigid con‘ 75 ' 4 2,127,083 tact arm coupled with said block and rotatably driven by said block, a plate ?xed to said shaft to turn therewith, said last named plate having a locking driving connection with said block for rotating the same while permitting relative axial movement thereof, said block having a central recess formed in the rear face thereof, and a spring between said last named plate and said block and seated in said recess to cause said 10 block to impose pressure onsaid arm to hold said arm in contact with said ?xed contacts. I sure on said arm to maintain said arm in con- tact with said ?xed contact. 3. A rheostat comprising a plate carrying ?xed contacts, a sleeve ?xed to said plate, a shalt journalied in said sleeve, an insulating block ro tatabiy and slidably mounted on said sleeve, a rigid contact arm coupled with said block and rotatably driven by said block, a plate fixed to said shaft to turn therewith, said last named plate having a locking driving connection with said block for rotating the same while permit~ 5. A rheostat comprising a plate carrying ?xed ting relative axial movement thereof, a spring contacts, a sleeve ?xed to said plate, a shaft Jour seated between said block and said last named nalled in said sleeve, an insulating block rotat plate to cause said block to impose pressure on 15 ably and slidably mounted on said sleeve, a rigid said arm to maintain said arm in contact with contact arm coupled with said block and rotat~ said ?xed contacts, and a cover for the rheostat. ably driven by said block and having a central said cover having a projecting stop and said last aperture of a size to prevent contact with said named plate being adapted to engage said stop sleeve, said block having a channel formed across to limit the movement of said arm. the rear face thereof, a plate ?xed to said shaft 9. A rheostat comprising a plate carrying ?xed to turn therewith and ?tting in said channel to contacts, a sleeve ?xed to said plate, a shaft 20 cause rotation of said block and arm, said chan journalled ‘in said sleeve, an insulating block nel being su?icientlv deep to permit axial move rotatably and slidably mounted on said‘sleeve. ment of said block with respect to said last a rigid contact arm coupled with said block and 25 named plate, and a spring seated between said rotatably driven by said block, a plate ?xed to last named plate and said block to cause said said shaft to turn therewith, said last named 25 block to impose pressure on‘ said arm to maintain plate having a locking driving connection with said arm in contact with said ?xed contacts. said block for rotating the same while permit 6. A rheostat comprising a plate carrying ?xed ting relative axial movement thereof, a spring contacts, a sleeve ?xed to said plate, a shaft Jour seated between said block and said last named 30 nalled in said sleeve, an insulating block rotat plate to cause said block to impose pressure on ably and slidably mounted on said sleeve, a rigid said arm to maintain said arm in contact with contact arm coupled with said block and rotat said ?xed contacts, a cover for the rheostat, and ably driven by said block and havingv a central an inwardly projecting stop mounted on the in aperture of a size to prevent contact with said ner face of said cover and adjustable circum sleeve, said block having a channel formed across ferentially, said last named plate being adapted 35 the rear face thereof, a plate ?xed to said shaft to engage said stop to limit the movement of to turn therewith and ?tting in said channel to said arm. , cause rotation of said block and arm, said chan 10. A rheostat comprising a plate carrying nel being su?iciently deep to permit axial move ?xed, contacts, a sleeve ?xed to said plate, a ment of said block with respect to said last named ' shaft Journalled in said sleeve, an insulating 40 plate, said block having a central recess on the block rotatably and slidably mounted on said rear face thereof, and a spring between said sleeve, a rigid contact arm coupled with said block and said last named plate and seated in block and rotatably driven by said block, a plate 46 said recess to cause said block to impose pressure ?xed to said shaft to turn therewith, said last on said arm to hold the said arm in contact with named plate having a locking driving connec said ?xed contacts. , tion with said block for rotating the same while 'I. A rheostat comprising a plate carrying ?xed permitting relative axial movement thereof, a contacts. a sleeve ?xed to said plate, a shaft spring seated between said block and said last 60 Journalled in said sleeve, an insulating block ro named plate to cause said block to impose pres tatably and slidably mounted on said sleeve, a sure on said arm to maintain said arm in contact rigid contact arm coupled with said block and with said ?xed contacts, a cover for the rheo rotatably driven by said block, said contact arm stat, a member ‘having an inwardly projecting extending to engage contacts on opposite sides stop mounted on the inner face of said cover, of said shaft, a plate ?xed to said shaft to turn and means for adjusting said member circum ferentially comprising setting means carried by therewith, said last named plate having a lock said member and extending through an arcuate ing driving connection with said block permit slot in said cover, said last named plate being ting relative axial- movement thereof, and a adapted to engage said stop to limit the move 60 spring seated between said block and said last ment of said arm. named plate to cause said block to impose pres KASSON HOWE.