US870042A

US870042A - Resistance-adjusting device.

Info

Publication number: US870042A
Application number: US28228205A
Authority: US
Inventors: Hector P Mac Lagan
Original assignee: NAT RHEOSTAT Co
Current assignee: NATIONAL RHEOSTAT Co; NAT RHEOSTAT Co
Priority date: 1905-10-11
Filing date: 1905-10-11
Publication date: 1907-11-05
Anticipated expiration: 1924-11-05

Description

No. 870,042. PATENTED NOV. 5, 1907.

H. P. MAOLAGAN. RESISTANCE ADJUSTING DEVICE.

APPLIUATIOI FILED 00T.11l 1905.

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UNITED STATES PATENT OFFICE.

HECTOR P. MAC LAGAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO NATIONAL 'RHEOSTAT COMPANY, OF CHICAGO, ILIJINOIS, A CORPORATION OF ARIZONA TERRITORY.

RESISTANCE-mammina DEVICE.

Specification of Letters Patent.

Patented Nov. s, 1907.

Application led October 1l. 1905- Serial llo. 282.282.

To all 'whomy it may concern:

Be it known that I, Hnc'ron P. MAC LAGAN, acitizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Resistance-Adjusting Devices, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification. i

My invention relates to adjustable resistancev de#- vices and more particularlyfto such devices to be used for the regulation of smaller current flow, .such as that fiow through voltmeters, galvanometers, or other like delicate instruments, and the object Aof the invention is to provide a device which is of very-simple construetion and therefore inexpensive, and which is more eliicient and reliable than devices of a like character.'

I am aware of ,prior devices for adjusting current` flow such as devices in which carbon forms the resistance medium.. In these prior devices, however, the resistance conditions are not constant; that is, the coefficient of the resistance is not sufficiently small, consequently making such devices unreliable in the delicate class of work for which they are to be used. In my invention, however, the material used is Wire having a resistance coefficient which is practically zero and the resistance conditions for one position of the device will be practically constant. i

The construction of. my device will appear best by reference to the accompanying drawing, in which Figure 1 is a plan view, part of the cover thereof being removed, and Fig. 2 is a sectionaliview taken on lino 2 2 of Fig. 1. I I

The resistance medium of the deviceis composed of the wire 1 arranged to form the winding 2. This wire which is known on the market as I. A. I. A. wire, is o f a certain composition which renders the coefficient thereof practically zero and which renders it very hard and tough. The winding is of cylindrical formas shown, and the wire may be wound in any manner about the core 3. The winding is best arranged, however, by having the core of some flexible material,l

such as paper, fiber, rubber or other flexible insulating material, which in its normal straight position is wound with the wire and subsequently bent to assume the cylindrical shape as shown. To support the winding I provide a cylindrical core or block 4 also of insulating material, such as wood, and the winding core after ythe wires have been placed thereon yis bent around the cylindrical face 5 of the block to rest against the flange 6 and is then secured in place by being glued to the block, or, as shown, by means of screws or nails]l y7 driven through the core 3 into engagement with the block. The wire which is normally unnsulated wound around the core to leave insulating space bea with the resistance wire.

tween the coils, and after the winding is completed I apply insulating material between the coils, and I preferably use a solution of silicate of soda, this being easily applied with a brush and which eventually I' hardens to almost the consistency of glass and thus also protects thefwindings against mechanical injury. The core 3 may also be covered with a coating of this material before the -windings are applied. From the center of the block extends a pivot post 8 to whichlis pivoted the adjusting lever mechanism for engagement The switch blade or Contact lever 9 for thisl mechanism is of springy material` and extends radially from the pivot post so that its end 10` may have pressing engagement along the upper edge y l1 of the resistance winding, and as the switch lever '70 is rotated this end will travel successively over'the ends of the various winding coils. i

To actuate the switch blade I provide the actuating handle or lever 12 secured with the switch lever to thev hub 13 to form a unitary structure whichv is held in place on the pivot post by means of the pivot screw 14. The switch lever and actuating lever are spaced so that with the cover 15 in position. the switch lever will be at the interior thereof and the actuating handle atl the outside thereof. This cover when in position engages about the outer edge of the flange 6l and vmay be secured thereto by nails or screws 16. To apply the cover the screw 14 is removed 'and the switch blade `and the lever frame and-the hub 13 can readily-be slipped through the opening 17 throughthe cover, and 85 the screwbeingthen again secured in position the device is ready for, operation and the parts thereof entirely inclosed-and protected.

Suitable terminal posts may be provided for the

terminals

18 and 19 of the winding, but I have shown the terminal posts 2O and 2l extending through themounting block to the base'thereof and are provided with threaded openings 22 for' receiving threaded terminal pins. of leads.4 The pivot post for tho'aetuating lever also extends through the mounting block and is also provided with a threaded opening 23 for the receptionof lead tips. One-terminal of the circuit for which the resistance is to be adjusted connects with the 'switch blade pivot post, and the other limb of the circuit by connection'to the

terminals

20 and 21 serially includes more or lessof the resistance winding, depending upon the position of the switch blade with `respect thereto.

The insulating material, or sodium silicate in this case, f is not applied to the edge 11 along which the end of and can be used for the most delicate work. The composition of the wire used renders the resistance con- I stant and the resistance in circuit remains constant for along-one edge of the band.-

vice extremely useful and desirable when used in 0011-' nection with such delicate instruments as voltmeters, galvanometers, or the like. 'v

' I-do not'wish to be limited, however, to the precise arrangement and -treatment of the partsl as slio'wnand described,- as changes may, readily be madewithout departing from the spirit of the invention.

I claim as new, however, and desire to secure'by Letters Patent:

1. In a device ot the class described, the combination with a resistance winding formed of a wirewound transversely around a band across the edges thereof, of a contact lever adapted for engagement with the adjacent turns 2. In a device of the class described, the combination with a resistance winding formed of wire wound transversely around the wall of a cylindrical shell and across the edges thereof, of a rotatable contact lever pivoted at the center of said shell and having a contact for' engagement with the ends of adjacent' coils along an edge of said shell. 1

3. In a ydevice of the class described, the combination 'with a cylindrical mounting block, of a resistance winding formed of wire wound transversely around the wall of a cylindrical shell across the edges thereof, said shell being mounted about the cylindrical face of the block, and a ro tatabie `contact lever pivoted at'the center of said 'block and having a contact for engaging the wire at the ends of.

adjacent coils along one edge of the shell.,

. 4. In a device of the class described, the combination with a winding formed of wire wound around the wall or' a cylindrical shell across the edges of the shell, of a contact lever pivoted at the center of said shell and adapted upon rotation to engage the wire at the end of the adjacent coils along one edgeof the shell, an actuating lever for said contact lever, and a cover for said device disposed between the actuating and the contact levers whereby said actuating lever will be at the outside of the cover and the contact lever at the inside of the cover.

5. In a deviceoi.` the class described, the combination with a cylindrical mounting block, of a resistance coil in the'form of a flexible sheet wound transversely vwith wire across the edges thereof and subsequently bent cylindrically to be secured about the cylindrical surface of the mounting block and engaging at its end with the end of adjacent coils along one edge of the sheet, Athe end of the contact arm upon rotation of the arm passing along the edge of the sheet into successive engagement with the ends of adjacent coils. j

6. In a device of-the. class described, the combination with a cylindrical mounting block,. of a resistance coil thereon, said resistance coilA being in the. form of a continuous winding mounted on a flexible strip or ribbon subsequently bent into a cylindrical form to lit about the cylindrical edge of the mounting block, the upper edge of said coil extending a slight distance above the mounting block, a lever pivoted at the center of the block, and a contact on said lever bearing against the upper edge of said winding, rotation of said lever causing said contact toibe carried over the edge of the winding into successivo engagement with'the coils thereof.

7. In a device of the class described, the combination with a resistance winding wound with a non-insulated 8. In a device of the class described, the combination with a resistance coil composed of non-insulated wire wound transversely over a flexible strip or ribbon of insulating material, adjacent coils being slightly separated and the strip with the windings thereon being subsequently hentto form a cylindrical shell, insulating vmaterial in the form of sodium silicate applied between and on the winding to insulate the coils thereof and to protecty them against mechanical injury, the top edge of the winding being left free from said insulating material, and a contact on said lever pressed thereby against the edge of the winding of the coil, rotation of the lever causing the contact to be carried about said edge into successive engagement with the coils of the winding.

9. In a device of thev class described, the combination with a cylindrical mounting block having -n horizontal flange at its'lower end, ofn resistance coil in the form of a continuous winding wound on a flexible strip or ribbon of insulating material subsequently bent in the form of a 4cylindrical shell and secured about the' cylindrical edge'4 of the mounting block to rest on said-flange, the upper edge of said coil extending a distance` above thev mounting block, a pivot post at the center of said mounting block, a lcontact arm pivoted to said pivot post and engaging at its end on the upper edge of said winding, a separate actuating handle pivoted to said pivot post and secured to the AContact lever, and an inclosing shell for the device adapted to be disposed between the actuating lever and the contact lever vwhereby the actuating lever only will be at the exterior of the cov'er, said cover being secured about the cylin- Idrical edge of the flange.

10. An adjustableresistance device composed of a cylindrical mounting block of insulating material, a cylindrical shell secured about the mounting block, a resistance winding wound continuously about said shell to form transverse coils whose vertical edges are disposed to form a circular contact edge, an actuating arm pivoted at the center of the mounting block, and a contact on said arm held in spring engagement with said resistance edge, rotation of said arm causing said contact to be carried about said edge in successive engagement` with the ends of the coils composing said-edge.

1 1. An adjustable resistance device'composed of a cylindrical mounting block of insulating material, aA cylindrical shell secured about the mounting block, a resistance winding 'wound continuously about said shell to form trans` verse coils whose vertical edges are disposed to form a circular contact edge, .an actuating armpivoted at the center of the mounting block, and a contact on said arm held in spring engagement with said resistance edge, rota` tion of said arm causing said contact to be carried-about snidedge in successive engagement with the ends of the coils composing said edge, the wire forming the winding being normally uninsulated and wound to leave spaces between coils, said spaces'being subsequently lled with insulating material. adapted to harden to maintain electrical separation of thecoils and to protect them against mechanical injury.

I 12. An adjustable resistance device composcdof a cylindrical mounting block of insulating material, a cylindrical shell secured'about the mounting block, a resistance winding wound continuously about said shell to form trans verse coils whose vertical edges are disposed to form a circular contact edge, an actuating arm pivoted at the center lof the inountingrblock, and a contact on said arm held in spring engagement with said resistance edge, rotation of said arm causing said contact to be carried about said edge in successive engagement with the ends of the coils composing said edge, the cylindrical shell being normally in the-form of a band or ribbon b y which the wire is wound and subseduently bent with the wire thereon into the cylinv drical form.

In witness whereof, l hereunto subscribe my name this 9th day of October A. D., 1905.

. Hnc'ron i. MAC LAGAN.

Witnesses:

CHARLES .I." SCHMIDT, LEONARD W. NovANnsn.