US1776664A - Rheostat - Google Patents

Description

Patented Sept. 23, 1930 PATENT, OFFICE THOMAS RHODUS, OF CHICAGO, ILLINOIS Application filed November 4, 1926. Serial No. 146,115.

This invention relates to that type of rheostats in which a curved core supports a spiral winding of resistance wire to constitute the stationary member of the appliance, with the socompanion adjustable contact member having movement in a curved path and in contact with such winding, an example of which is shown and described in my former application Serial No. 7 6,141, filed Dec. 18, 1925. 10.And-thevarious objects of the present improvements are To provide a structural formation and combination ofparts whereby the curved supporting core with its winding of resistusance wire has supporting connection with a wall of the enclosing casing in a simple, substantial and insulated manner.

To provide a simple and effective formation and association of parts, wherein the curved supporting core with its windings of resistance wire is held in its proper and normal position Within the enclosing casing and in proper operative relation to the companion movable contact member.

To provide a simple and effective formation and association of parts "wherein the curved supporting core of the resistance wire and the wall of the enclosing casing of the rheostat are penetrated in an insulated manner by the current carrying means and held thereby in working relation.

To provide a simple and effective formationa'nd association of parts, wherein the resistance member comprising a curved supporting core and its windings of wire is held in proper and normal position and in proper insulated operative relation to the companionv movable contact member, allas will hereinafter more fully appear.

In the accompanying drawing v Fig. l'is atop or plan view of'a rheostat embodying the invention, with parts of the enclosing casing broken away and with parts in section. Fig. 2, is a sectional elevation on line 2-2 Fig. 1. a

Fig. 3, is a detail section on line3-3 Fig. 1. Like reference numerals indicate like parts in the different views.

In the construction shown, the enclosing shell or casing affords an enclosure and the sole supporting means for the rheostat parts, and to such end preferably comprises a circular wall 1 to the upper and lower ends of which are secured orificed closure heads 2 and 3 adapted to protect the rheostat parts and afford proper ventilation. In the present improvement the rheostat parts are mounted in said enclosing casing and are'of a detail construction as follows.

r The stationary resistance element is preferably of the formation described in my prior Patent No. 1,230,221, of June 19, 1917 and comprises a series of open and flat spiral windings 4c of wire wound upon a curved insulating core 5 preferably of the split ring type, with the ends 6 thereof formed to overlap and having aligned orifices for the passage of the screw bolt 11 which in the preferred construction is a terminal post and the holding and current carrying means of the present improvement. Insulating material is arranged between the outer face of the overlap ends 6 of the core 5 and the inner face of thecircular wall 1 of the enclosing casing and preferably of the form of an intervening orificed block 7.

Insulating material is arranged in aligned relation to said block 7 and in bearing contact with the'inner face of the overlap ends 6 of the supporting core 5 aforesaid and preferably in the form of an inner block 8 of a counterpart orificed formation to'that of-the block 7 aforesaid. Insulating material is arranged in aligned relation withblocks 7 and 85. 8 and in bearing contact with the outer face of the wall 1 of the enclosing casing of the rheostat and preferably in the form of an outer block 9 ofa counterpart orificed formation to the blocks 7 and 8 aforesaid.

In the construction shown, the bolt 11 is insulated from the wall 1 of the casing and from the curved core 5 of the resistance element, and in the preferred construction, a tubular sleeve 10 of high insulating material extends through theorifices of the plurality of blocks 7 8 and9 and through orifices of the Wall land of the overlap core ends 6, to provide an. insulating encasement for preferably the shank of a screw bolt 11, by which the parts are drawn and firmly secured together.

In the preferred construction, the screw bolt 11 constitutes'both a holding means and a current carrying means: the outer end of the screw bolt 11 carries the usual pair of adjustable nuts 12 for effecting. the usual tightening or clamping. action of the bolt, and in addition constitutes the attaching terminal or terminal post for one of the line wires of the circuit in which the rheostat is used; and the inner end of the bolt 11 is provided with the usual fixed head adapted to secure the journal and supporting bracket 13- of the movable contact member of the rheostat in place upon the; inner face of the aforesaid; nsulat nab cck h the. said-fix d a of the bolt 11 inelectric contact with the adjacent portion, Of said bracket 13. v

The journal and supporting bracket 13 abone referred to .is preferably formed from a strip of plate meta-1 and bent, to an, angular form, with its respective arms formed with orifices, One of saidorificesisadapted to re ceive the shankof the screw bolt 11 aforesaid, while the other orifice, which is positioned in centraljrelation to the. curve of the core 5 aforesaid, provides a journal bearing for the carrying shaft ofthemovable contact memher now to be described.

The said movable contact member of the; rheostat is; preferably in the form of a revolubl'e roller 14, resiliently mounted; on a. central carrying shaft 15 journalled in the above described orifice in the. bracket 13,

and with suclrmountingpreferably comprismg a guide; head 15 finedon the end of. the shaft 15 and having guide ears for a sliding arm 17 on the outer end of which is journalledthe aforesaid contact roller 14. Associated with said guide. head 16 and sliding arm 17, 1s a compression SPI'lIig; 18, the tendency of wh ch is to move the arm 17 outwardsandmaintain; the roller 14 in contact w th the resistance, winding 4 of the stationary res stance member ofthe rheostat,

and in such; constructionthecontact roller 14,,guidehead l6and arm 17; are formed of metal or like conducting material.

At itsotherand upper end the carrying shaft 15 is provided with an operating hand le ,'or;.knob 19 the lower end of'whichis preferably formed with a reduced circular neck adapted for bearing engagement; in a central orificeinthe'upper head 2 of the enclosing; casing of the rheostat.

The other and companion terminal post for the attachment of the other.v line wireof the, circuitin which the rheostatis arranged,

is; of, a substantially counterpart construc.

tion te the terminal post; 11- above described and has-adjacent relation; thereto as; shown, andpreferably comprises a screw bolt 20 provided with an insulating sleev e 21 and a pair of. adj stable nuts: 22, whi h n onnection with a pair of orificed abutment blocks 23, and an orifice in the wall 1 of the enclosing casing through which the said sleeve 21 passes, provides an insulating mounting for such companion terminal post with its screw bolt 20 electrically connected to the end of the resistance winding 4 opposite to. the end of such winding which has. connection with the first mentioned terminal post.

Another part of this invention involves an enclosing means for the above described terminal posts, adapted to afford ready and convenient access to the same and'to such end comprises a wall 24 of preferably plate material'of preferably an approximately U shape, provided. with attaching flanges 25 at its respective ends bywhich it issecured by screw bolts or like fastening means to the: wall 1 of the enclosing housing of the rheostat. The wall .24 and, preferably the. crownportion of said Uv shaped wall 24 is. formed with, a. receiving orificev through which the cable carrying theline wires,- of.

Auiotherpart of this invention involves means. for supporting the carrying core. 5,

and its windings 4 of resistance wire in proper position with relation to the enclosing casing and the movable contract member of the rheostat, and to such end comprises preferably a plurality of blocks 30 having re-' cesses of insulating material and preferably Lshaped, arranged in. the upper and lower. corners of the enclosing casing of the rheostat, with the recesses of said blocks.- forming saddles or rests and. abutments for, the: core 5 and its windings aforesaid, Inthe,

construction shown, a pair of said saddle blocks; of I insulating material engage the, upper edgeof the, core 5, and a single saddle, block in staggeredrelation to said pair of blocks, engagesthe lower edge of the "core, 5; Lateral shift; or displacementofthesaddle blocks 30 is. prevented preferably by a pair of holding prongs 31 to each block 30, with said prongs preferably formed. by slitting the. plate metalheads 2 and 3. ofthe enclosing casing to form said prongs, which are then bent into parallel relation to; receive,

a saddle block between them. I

I Having thus fully describedmy invention,

what I claim and desire to secure by Letters;

Patent is 1. In a rheOStat, the, combination, of an enclosing casing having aside wall formed With an orifice, a stationary resistance: member of a curved sha e and having an orifice, an orificed block insulating material arranged between the orificed part of the resistance member and the orificed side wall of the enclosing casing, a second orificcd block of insulating material arranged on the inner side of the orificed part of the resistance member, a third orificed block of insulating material arranged on the outside of the orificed side wall of the enclosing casing, an L shaped bracket, one arm of. which has contact with the second orificed block aforesaid and is formed with an orifice, a screw bolt passing through said ori- IS fices and attaching the said parts together,

a sleeve of insulating material encasing a portion of the shank of said bolt, an adjustable current carrying contact member making contact upon the stationary resistance member, an orifice in the other arm of the aforesaid bracket, and an operating shaft for said adjustable contact member having bearing in said last mentioned orifice.

2. In a rheostat, the combination of a re 3 sistance member of a curved shape and having an orifice, a current carrying bracket having two arms one of which has an orifice,

a terminal screw bolt passing through the aforesaid orifices and attaching said parts i w together, a movable contact member making contact with said resistance member, a guide member comprising a central portion and two arms, said movable contact member being supported by said guide member, and a carrying shaft associated with the other arm of the aforesaid bracket and having contact with the center portion ofsaid guide member at a point between the inner ends of the arms of said guide member, the arms of 40 said guide member extending parallel to said shaft.

Signed at Chicago, Illinois, this 1st day of November, 1926.

THOMAS RHODUS.

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