US1402587A

US1402587A - Adjustable resistance

Info

Publication number: US1402587A
Application number: US291978A
Authority: US
Inventors: Evershed Sydney
Original assignee: EVERSHED; VIGNOLES Ltd
Current assignee: EVERSHED; VIGNOLES Ltd
Priority date: 1919-04-22
Filing date: 1919-04-22
Publication date: 1922-01-03
Anticipated expiration: 1939-01-03

Description

S. EVERSHED.

ADJUSTABLE RESISTANCE.

Patented Jan. 3, 1922.

4 SHEETS SHEET 1.

INVENTOR ATTORNEY S. EVERSHED.

ADJUSTABLE RESISTANCE.

APPLICATION FILED APR. 22. I9I9.

1,402,587. ifii ed 3, 1922.

. HEETSSHEET 2.

S Eversfieal.

' BY aZ/QM ATTORNEY S. EVERSHED.

ADJUSTABLE-RESISTANCE.

PLlCA N FILED 1 ,402,587 Patented Jan. 3, 1922,

4 EEEEEEEEEEEE 3- .14 Y X Y S. EVERSHED.

ADJUSTABLE RESISTANCE.

APPLICATION FILED APR. 22, 1919.

Patented (12111.3, 1922.

4 4 SHEETSSHEET 4.

ATTORNEY UNITED STATES PATENT OFFICE.

SYDNEY EVER/SHED, OF LONDON, ENGLAND, ASSIGNOR OF ONE-HALF TO :EVERSHED I AND VIGNOLES LIMITED, OF LONDON, GLAND.

ADJUSTABLE RESISTANCE.

Specification of Letters Patent.

Patented Jan. 3,1922.

Application filed April 22, 1919. Serial No. 291,978.

To all whom it may concern:

Be it known that I, SYDNEY EvERsHED, a subject of the King of Great Britain and Ireland, and residing at Acton Lane Works, Chiswick, London, WV. 4., England, have invented certain new and useful Improvements in and Relating to Adjustable Resista'nces, of which the following is a specification.

'The invention relates to adjustable resistances formed by winding a resistance wire in a spiral round an insulator support and in which the adjustment is eifected by relative sliding or rolling between the wire and a suitable contactor.

The objects of the invention are (1) to provide resistances, of the type described, in the form of a ring in which the resistance" of, the convolutions or turns of resistance wire is either accurately uniform or varies accurately in any desired and prearranged manner around the ring; (2) to facilitate the construction of accurate lVheatstone bridges, potentiometers, and other socalled null method apparatus working on the same or kindred principles, by means of a resistance of ring form adjustably divided into two or more portions by means of one or more conductors in contact therewith and capable of relative motion thereon; (3) to facilitate the construction of apparatus for communicating information from one place to another by means of resistance variations in electric circuits on the principles described in British Patent No. 8784 of 18-91.

The invention consists in a supporting ring adapted, by forming a gap or other discontinuity in it, to be interlinked with the mechanism of a wire-winding machine; a uniform resistance wire Wound in a spiral around the said ring iii accurately spaced convolutions; means for insulating the said resistance wire where required and one or more contactors adapted by movements of relative rotation to'make contact with the resistance wire thereon at any desired angular position or positions.

The invention also consists in a supporting ring adapted, by forming a gap or other discontinuity in it, to be interlinked with the mechanism of a wire-winding machine; a uniform resistance wire wound in a spiral round the said ring in accurately spaced convolutions; means for insulating the said resistance wire where required and one or more contact arms adapted to move about an axis normal to the plane of the ring and to make contact with the resistance wire thereon at any desired angular position' or pos tions.

The invention also consists in a supporting ring of insulating or insulated material adapted by the shape of itscross section to give rigidlty in the plane of the ring; a gap in the ring adapted to permit it to be interlinked with the mechanism of a wire-winding machine; a uniform resistance wire wound in a spiral round the said ring in accurately spaced convolutions; means for insulating the said resistance wire where required and one or more contactors adapted to make contact with the resistance wire on the periphery of the ring at any desired angular position or positions.

The invention also consists in a supporting ring of insulating or insulated material adapted by the shape of its crosssection to give rigidity in the plane of the ring; a gap in the ring adapted to permit it to be interlinked with the mechanism of a wire-winding machine; indentations in the ring adapted to receive and space the convolutions of a resistance wire; a uniform resistance wire wound in a spiral round the said ring in the said indentations in accurately spaced convolutions; and one or more contact arms adapted to move about an axis normal to the plane of the ring and to make contact with the resistance wire thereon at any desired angular position or positions.

The invention also consist in a ring resistance in which the supporting ring of insulating or insulated material is adapted by the shape of its cross section to give rigidity in the plane of the ring and further adapted, by the shape of its cross section to give such flexibility in a direction normal to the plane of the ring as will, in conjunction with a narrow gap or discontinuity in the same, permit theringtto be interlinked with the mechanism of a wire-Winding machine for the purpose of winding the resistance wire in a spiral on the supporting ring.

Theinvention further consists in a sevcred resistance ring of the type described,

in combination with a bond or other me- 'tations in the ring;

sistance ring to the original plane of the uncut supporting ring and firmly securing 1t therein. v The invention is illustrated in the accompanying drawings in which like letters refer to like parts.

In these drawings; .4 Figure 1 is a plan, and V I Figure 2 a sectional elevation of one form of .ring resistance constructed according to the present invention in whic'hthe contactor takes the form of a rolling'contact;

Figure 3 shows a modification in which a sliding contactor. is employed instead of a rolling contactor;

Figures 4 and 5 illustrate convenient means which may be adopted for securing an accurate spacing of the convolutions of resistance wire by means of indentations;

Figure 6 shows one way of forming inden- Figures 7 and 8 illustrate a ring of nearly square section substantially rigid in a direction normal to the plane of the ring and formed with a large gap;

Figure 9 and 10 represent a similar gapped ring of different cross section;

Figures 11 and 12 show a ring sufiiciently thin to give flexibility in an axial direction and formed with a narrow gap;

Figures 13, 1 1, 15 and 16 show'me'a'ns of bonding the rings at the gap;

Figures 17 and 18 show rings in which the radialwidth increases from a minimum at one end to a maximum in the middle, and a minimum at one end to a maximum at the other end respectively.

Figure 19 illustrates a convenient form of machine for w1nd1ng the wire on to rings as described above.

In carrying the invention into effect in the form shown by way of example in Figures 1 and 2, the supporting ring r may either be made of a suitable insulating material such as hard ebonite or the like, or of metal covered with a suitable insulating var- .nish or enamel. The ring has. a gap at gr sufliciently wide to enable it to be interlinked with a winding machine for the purpose of winding on the spiral convolutiofis of resistance wire w. lhe adjust- I able or travelling contactor is shown by way lin of example as an elastic disc 0 which, being freely pivoted in one end, of the arm Z carried by the axle a, makes a rolling contact with the resistance wire w. The other end of the arm Z makes sliding contact with the slip ring a. The ends of the resistance wire are fastened toterminals 2? and t and a terminal t on the slip ring enables the necessary electrical connection with the travelcontactor 0 to be made. In Figure 3 a s iding contactor 0 is shown as an'alternative to therolling disc contactor shown in

F1gures

1 and 2. The resistance wire is sulation on the wire may be removed throughout a narrow band round the ring, to

enamel or other'suitable insulating material, and aftenthe winding is completed the inform a suitable path for the travelling contactor.

Figures 1 and 5 illustrate convenient means which can be adopted for securing accurate spacing of the convolutions of resistance wire w by means of indentations n n, in the supporting ring 1*.- In Figure 4 the indentations are in the form of shallow grooves on the inner and outer peripheries of the supporting ring. These grooves may be cut in any suitable gear cutting machine.

In Figure 5 the indentations n n are merely notches formed in the edges of the ring, a modification which permits them to be formed by squeezing the supporting ring in a suitable press between rings of steel or other hard metal upon which corresponding vteeth have been cut in a gear cutting machine. The operation of forming indentations in this way is illustrated byway of example in Figure 6, where r is the support.

ring interlinked with a winding machine.

The supporting ring r is fixed in a position concentric with the turntable l of the winding machine, by means of the adjustable and

detachablesu'pports

2, 2, and is interlinked with the windin drum 3 which is driven by the motor 4. he stock of resistance wire 5 is wound onthe wire drum'6 and is carried therefrom one, thezring' 1* by means of guide pulleys and}; winding arm which are fixed on the drum 3. The winding arm is omitted in the drawing in order to show the wire passing on to the ring 1' at'the'winding point e. The turntable l' is driven at any desired relative speed by means" of change wheels 8, 9 and 10 which are geared to and driven by the motor 4. "A friction brake 7 applies the necessary'tension to the resistance wire. When, in the course of the revolution of the turntable 1, a supporting'clamp 2 approaches the back of the winding drum 3 it is detached from the turntable and ring. and re placed in a position in front of the winding drum near the winding point 6.

When the resistance wire is of sufficiently small diameter it is easily wound in tight and flat convolutions on a ring of rectangular cross sections, the tension being sulficient not only to bend the wire round the ring but to pull it tightly across the fiat sides of the ring. When the wire is too large in diameter to permit this to be done without the use of excessive tension, a modified form of supporting ring like that shown in F igures 9 and 10 may berused with advantage,

7: the elliptical or oval section permitting a stout wire to bend closely round the supporting ring by the application of a moderate tension.

When the supporting ring has a section which makes it substantially rigid in a di rection normal tothe plane of the ring, the gap 9 must be at least as wide as the axial width of the winding drum of the winding machine. Such a ring is illustrated in Figures 7 and 8, the section shown being nearly square, and also in'Figures 9 and 10. On the other hand, if the supporting ring is sufficiently thin to give it the necessary flexibilty in an axial direction, as illustrated 3 0 in Figures 11 and 12, the gap may be re"- duced in width to that of asaw cut, and the ring may be readily interlinked with a wind- ,ing'machine by pulling apart the two ends m and y as indicated by dotted'lines in Figure 11. Removal from the winding machine,

after winding on the resistance wire, is performed in the same manner; the flexibility not being appreciably altered by the presence of the convolutions of wire. 7

After winding on the resistance wire the two ends of the supporting ring may be fastened rigidly together by means of a bond 5, as shown in Figures 13, 14, 15 and 16. In Figures 13 and 14 the bond is suitable for a more or less rigid ring which has a wide gap, and consists of a metal piece accurately machined to slide into and close the gap 9, where it is retained in position by means of screws which pass through the 5 ends m y of the ring 1*. Figures 15 and 16 show a bond suitable for a flexible ring in which the gap consists of a narrow saw cut. In Figures 1 and 3 the convolutions of y resistance wire have a uniform resistance per turn from one end of the resistances to the other because the radial width of the supporting ring is uniform. By making the supporting rings of non-uniform radial width the resistance wire wound thereon will have a non-uniform resistance per turn,

the variation of resistance per turn correspending with the variation in the perimeter of the transverse section of the supporting ring.

an example of this modification,

Figure 17 shows a supporting ring in which the radial width is a minimum at the gap 9 and increases at a uniform rate from the ance per turn from w to m and uniformly decreasing resistance per turn from m to 3 The axle a which carries the contact arm is concentric with the inner circular perimeter of the resistance ring. Figure 18 shows another modification in which the radial width of the supporting ring increases uniformly from a minimum at the end a: up to a maximum at the other end y. In Figures 17 and 18 both the inner and outer peripheries of the supporting ring are circular and consequently the rates of increase of resistance per turn are uniform.

If desired, the supporting ring may be constructed with a non-circular periphery calculated to give any desired law of variation of width. Thus any desired law of variation of resistance per turn may readily be obtained. The constructions described and illustrated in the drawings may be modified in other ways without departing from the essence of the invention.

It will be understood that in applying the invention for, the purpose of communicating information from one place to another the resistances constructed in accordance with the invention may either be used to vary the ratio of currents in two circuits or they may be used as the variable resistances of a system of circuits connected on the principle of a Wheatstone bridge, as described in British Patent No. 8784 of 1891.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is 1. An adjustable resistance comprising a supporting ring, resistance wire spirally wound thereon of which the turns are accurately disposed round the ring, a contactor and means for effecting adjustment by relative movement between the wire and the contactor whereby said movement will result in a predetermined variation in the resistance.

2. An adjustable resistance comprising a supporting ring having a discontinuity therein adapting it to be interlinked with the mechanism of a wire-winding machine; a uniform resistance wire wound in a spiral round the said ring in accurately spaced convolutions; means for insulating the said resistance wire where required and a contactor adapted by a movement of relative rotation to make contact with the resistance w1re thereon at any desired angular position.

3. An adjustable resistance comprising a would have a uniformly increasing resistsupporting ring adapted, having a gap or other discontinuity in it adapting it, to be interlinked with the mechanism of a wirewinding machine; a uniform resistance wire wound in a spiral round the said ring in accurately spaced convolutions; meansfor in sulating the said resistance wire-whererequired, and a contact arm adapted to move about an axis normal to the plane of the ring and to make contact with the resistance wire thereon at any desired angular position.

4. An adjustable resistance comprising a supporting ring adapted by the shape of its cross section to give rigidity in the Jplane of the ring; a gap in the ring adapte" to permit it to be interlinked with a mechanism of a wire-winding machine; a uniform resistance wire wound in a spiral round the said ring in accurately spaced convolutions; means for insulating the said resistance wire where required and a contactor adapted to make contact with the resistance wire on the periphery of the ring at any desired angular position. 5. An adjustable resistance comprising a supporting ring adapted by the shape of its cross section\to give rigidity in the plane of the ring; a gap in the ring adapted to permit it to be interlinked with the mechanism of awire-winding machine;'indentations in the ring adapted to receive and space .the convolutions of a resistance wire; a uniform resistance wire wound in a spiral round the said ring in the said indentations in accurately spaced convolutions; and a contact arm adapted to move about an axis normal to the plane of the ring and to make contact with the resistance wire thereon at any desired angular position. t

6. A ring resistance comprising a supporting ring adapted by the shape of its cross section to give rigidity in the plane of the ring and further adapted, by-the shape of its cross section, to give such flexibility'in a direction normal to the plane of the ring as will, in conjunction with a narrow gap or discontinuity in the same, permit the ring to be interlinked with the mechanism of a wirewinding machine for the purpose of winding the resistance wire in a spiral on the supporting ring.

7. An adjustable resistance comprising a discontinuous supporting ring, flexible in an axial direction, resistance wire disposed thereon in accurately separated convolutions and detachable means for securing rigidity of the aforesaid wound ring.

8. An adjustable resistance comprising a discontinuous supporting'ring,'fiexible in an axial direction; resistance wire disposed thereon inaccurately separated convolutions, a bond rigidly attached to the discontinuous ring and bridging the discontinuity, a con- 65'tactor contacting with the resistance wire and means for effecting adjustment of resist- "ance by relative movement between the wire and the contactor.

9. An adjustable resistance comprising a supporting ring adapted, by forming a gap or other discontinuity in it, to be interlinked with the mechanism of a wire-winding machine; a uniform resistance wire wound in a spiral round the said ring in accurately spaced convolutions; means for insulating the said resistance wire where required, and contact-arms adapted to move about anaxis normal to the plane of tlie ring and to make contact with the resistance wire thereon at any desired angular position.

10. An adjustable resistance comprising a supporting ring, resistance wire thereon of which the resistance of the convolutions or turns is accurately disposed round the ring, a plurality of contactors and means for effecting adjustment by relative movement between the wire and the contactors.

11. An adjustable resistance comprising a supporting ring adapted, by forming a gap or other discontinuity in it, to be, interlinked with the mechanism of a wire-winding machine; a uniform resistance wire wound in a spiral round the said ring in accurately spaced convolutions; means for insulating the said resistance wire where required, and a plurality of contactors adapted by a movement of relative rotation ,to make contact with-the resistance wire thereon at any desired angular position. .7

' 12. In adjustable resistance comprising a 100 supporting ring adapted by the shape of its cross section to give rigidity in the plane of the ring; a gap in the ring adapted to permit it to be interlinked with the mechanism of a wire-winding machine; a uniform re- .105-

adapted to 'make contactwith the resistance 1 wire on the periphery of the ring at any desired angular position.

13. An adjustable resistance colnpri'sin a supporting ring of non-uniform ra ial width,iresistance wire thereon of which the resistance ofthe convolutions or turns is accurately disposed round thering, a contactor and means for effecting adjustment by relative movement between the wire and the contactor.

14. An adjustable resistance comprising a supporting ring with a non-circular periphery, resistance wire thereon of which the resistance of the convolutions or turns is accurately disposed round the ring, a contactor and means for effecting adjustment by relative movement between the wire and the contactor.

15. An adjustable resistance comprising a discontlnuous supporting ring, a uniform resistance wire wound in accurately separated turns around said ring and a contactor adapted by a movement of relative rotation between the wire and the contactor to make contact with the resistance wire thereon at any desired angular position. v

16. An adjustable resistance comprising a discontinuous supporting ring, a uniform resistance wire wound in accurately separated turns around said ring and a contact arm adapted to be moved about an axis normal to the plane of the ring and to make contact with the resistance .wire. In testimony whereof I have signed my name to this specification.

SYDNEY EVER-SHED.