US934973A - Rheostat. - Google Patents

Description

H. T. JONES.

RHEOSTAT.

APPLICATION FILED 001219, 1908.

gg., Patented Sept. 21, 1909.

5mi/y 7.702265. BY

UrrE

ATENT QFFICE.

HENRY ai. Jones, or BELLEVUE, PENNSYLVANIA.

EnEos'rAr.

Specification of Letters Patent.

ratentealsepeai, 190e.-

Appleation filed. October 19, 1908-. Serial No. 458,484.

To oltwltofm 'it may concern:

Be it known that l, HENRY T. JoNEs,citi .zen of the United States, residing at Bellevue, in the county of Allegheny and State of .3 leimsylvania, have invented certain new Fil and useful Improvements in Rheostats, of which the following isa specification.v

My invention relates'to resistance devices, and more particularly to resistance devices of the imperfect contact type. As is well known, such devices usually consist of a pile or column of plates or disks of some material, such as carbon or graphite, which disks, owing to the peculiar nature of their `coniposition, make more or` less imperfect contact .with each other. When, however, pressure is applied to such a column or pile, the disks are forced into more intimate Contact, vand the resistance of the pile diminished. Also, the reduction of resistance is proportional to the degree of pressure applied'.

In its broader aspects, inyinvention seeks to provide an improved construction of such a resistance device, so that i-t may be adapted for' use' in controllers, dimmers, lightning arrestcrs, and other electrical apparatus in] which a resistance medium is employed.

More speciically, the invention aims to produce an improved rheostat. device having the above mentioned resistance medium a.

basis. v

' (lne object of the invention is, therefore,

to provide a resistance device of the above character so'constructed as to readily dissipate the heat generated by the passage of the current.

A further object is to provide a rheostat having a sweep arm of theordinary type so connected with my improved resistance device that the movement of such arm about itspivot will serve to vary the amount 'of current transmitted, as' in the well known forms of such apparatus.

A still further object of the invention is to provide a resilient connection betweenitlie v,

sweep arm and resistance device so arranged that it serves the double purpose of exerting pressure on said resistance device, and of returning the arm to its off position when the release'magnet becomes denergized.

lVith the above and other objects in view,

and to improve generally upon the efliciencyl and simplicity` of such apparatus, my invention consists in the construction and arrangement of parts hereinafter described,-

and illustrated inl the accompanying drawings, in whichl Figure l is a front elevation showing my improved rheostat, complete. Fig. 2 is a perspective view of one of my novel resistance elements, detached. Fig-3 is a side ele vation of .the device shown in Fig. l, parts being broken away. Fig. 4 is a diagram illustrating the circuits employed. v

Referring to the drawings in detail, l designa'tesl a `base or support of suitable size, which may be a panel of slate, or. similarv non-conductin material. On the front of such panel, an near one edge thereof, l sup port :my improved resistance device comprising a column or pile of conducting disksor plates 2, 3. As clearly shown in Fig. 2, each fof these disks has a central circular opening lt will be observed, by reference to Figs. l

and 3, that the disks 3 are of sinallerdiameter than the disks 2 and are arranged to alternate With them. ln this manner, por. tions of the disks 2 project beyond the edges of the disks 3 and thus give tothe column a corrugated appearance.' This corrugated surface, as is well known, has .the property of readily radiating heat, and thus serves to maintain the resistance device at a comparatively low ten'ipcrature while working.

I regard this as an important feature of my invention. While I have shown the series of disks or resistance elements as assembled in the form ofa vertical column, it is obvious that they may be readily arranged adjacent eachother in a horizontal row, or diagonally. y ,At the lower end of rod 4t is a nut 5, and above this is arranged a suitable block 6, on or against Which the first resistance element of the series rests. This block is `provided l with an oset or ear 6, for the'purpose hereinafter described. Albracket 7 is secured in the panel 1 and embraces block G, as shown. At the other end of the column or series of resistance elements, is another block 8, supported by brackets 9, set into the panel. Beyond the block 8 is 'a cup-shaped bracket 10, supported on a stud 11, and adapted to receivef and guide the end of the rod 4f.. lt

-Will thusbe seen that the series ot resistance elements is freely supported and held in position, solely vby the rod 4, in such manner that air can readily circulate around it on all sides. Connecting with the end elementv orp the series is a lead 12, to which is attached atlex'ible connector 13, secured at its other end to 'a clip 15, having a screw 14C passing therethrough. A

Connection is made with my improved rheostat by means o" the three usual binding posts 16, 17, 18, from which extend wires to the motor armature, line, and motor field, respectively, as indicated in Fig. d. The leads from these binding posts to the various parts of the device are herein illustrated as mounted on the front of the panel. It is evident'tliat they may be carried on the back of the-panel, if desired, however. From binding post 18 a conducting strip 1t) extends to a binding screvv 20, hereimrlter referred to.

From the binding post 17 extends a conducting strip 21, to a plate 22, secured to the panel near its center. 0n this plate 22 is pivoted', as at 24e, one end of a sweep arm 23, of usual construction, provided at its outer end With a handle 25. lhis arm 23 is adapted, when swung on its pivot to engage successively, with the first point contact 2G, the arc-shapcd contact segment 27, and the short circniting contact 231. conducting strip 28 extends Al'rom contact plate .T to clip 15, above described, and 'from this strip, extends a strip I5() to lorm one terminal of the usual no voltage release magnet 2E). rlhe binding screw 20, above referred to, forms the other tcrn'iinal ot 'this.magnet. From the short circuiting contact 31, extends a conductor 32 to the binding post l, connected to the motor armature. An arma ture 33 yis carried, as usual, by the sweep arm, for engagement with the poles of inagnet 29. A stop 34; limitsthe movements o'le the arm in the other direction. A stiftl helical spring has one end attached to the ear@a of the block G and the other end connected, as by a link 36, to a stud 337, set intothe arm Q3 at a pointY slightly removed from its eea-,ere

pivot. il conductor 38 (see Fig. extends from the lower end of theresistance column to the armature lead 32, thus completing the of column, thence through column ot re,

sistance elements and out through conductors 38, to conductor 32, binding post 16, and motor armature. A branch circuit can also be traced tlnough conductor 30, magnet 29, and conductor 19 to motor field. lll/'ith the arm in contact with 26 the resistance of thel column is a maximum and the starting current for the motor a minimum. is moved around over plate 27, however,

y it acts through spring to draw up block t5 and thus compress the column of resistance elements thereby gradually lessenmg its resistance, and allowing more and morecurreutto flow. Finally, when the arm. engages plate 2li, the resistance column is short-circuited, and the current reaches its maximum value.

lt. will thus be seen that l have provided a very simple, durable and compact resistance device, applieal'ile to a large variety ot uses,-

and it is thought the numerous advantages of my invention will be readily appreciated by those Vski] led iu the art.

l/Vhat l claim isln a rheostat, the combination W1th Va supporting` base, ot a sweep arm pivoted at one v end near the center thcrcot, an arc-shaped sci-ics oi contacts mountcd on one sidc ot.' the base with which thc other cud ot said arm cooperates, a column ol flat. conducting disks arranged near the other side ot said base, a block above which said conducting disks are held, a ixed rod on which said block and disks are both freely slidable, and a connection extending between said block and said arm, whereby, as said arm is vmoved on its pivot, it serves to force said block upward.

on said rod and thus compress said column ot disks. y

ln testimony whereof l aflix my signature, in presence ot two witnesses.

HENRY '.l. JONES. Witnesses J. lV. SnAY'roN, A. linnen.

As the arm

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