US1813592A

US1813592A - Machine for flattening filamentary wire

Info

Publication number: US1813592A
Application number: US376587A
Authority: US
Inventors: Wadsten Sten
Original assignee: Westinghouse Lamp Co
Current assignee: Westinghouse Lamp Co
Priority date: 1929-07-08
Filing date: 1929-07-08
Publication date: 1931-07-07
Anticipated expiration: 1948-07-07

Description

July 7, 1931. s. WADSTEN' MACHINE FOR FLATTENING FILAMENTARY WIRE 2 Sheets-Sheet 1 Filed July 8, 1929 INVENTOR ATTOR E v Patented July 7, 1 931 I UNITED STATES PATENT oar-ice STEN WADSTEN, OF BLOOMFIELD, NEW JERSEY, ASSIGKOB 1'0 WESTINGHOUSE LL11? COMPANY, A CORPORATION OF PENNSYLVANIA FOR FLATTENING IILAIEHTABY Application filed July 8, 1929. Serial 110. 376,587.

This invention relates to the manufacture of electron emission devices and relates more a particularly to production of a flattened filamentary wire for use as a cathode in such devices. I I

In the manufacture of certain types of electrical devices such as radio tubes, it is desirable to use a cathode consisting of a suitable metallic core such as nickel or platinum iridium alloy or of a suitable nickel alloy. The

core material employed for cathodes of the above character is initially produced in the form of a wire circular in transverse cross section. It then becomes necessary in order 15 to obtain the required voltage and amperage characteristics and the desired surface area to maintain a proper operating temperature to compress or roll out the core into a ribbon of a given thickness.

By reason of the minute dimensions of the wire, great difficulty has been encountered in attempts to successfully produce such wire in flattened form having a uniform thickness throughout its length. For example, a filamentary wire or core for a-radio tube such as that known as the 171A has an initial diameter of .0022 and must be flattened to a width of .0046 having a thickness of .0006. When compressing a fine hair-like body, such 30 as a filament wire, it hasbeen found not only to be necessary to employ a mechanism constructed with .precision but to provide a novel combination of machine elements so arranged and co-related as to apply the required pressure in a delicate and accurate manner to compress an initially round wire into a flat strip of'predetermined dimensions,

It will be appreciated that in the ordinary operation of rolling, as for example, the rolling of bodies, such as sheet metal or the like,

slight inaccuracies in thickness occur throughout the ama of the body after rolling by reason of the variation in the properties of softness and hardness of the material.

Under ordinary conditions such inaccuracies as do occur are not appreciable and have no detrimental effects in the ultimate product. hen flattening a-filament wire, however, of say .0022 to .025 of an inch diameter wherein the final thickness of the wire is in '-l he dimensions of thousandths of an inch, it will be readily appreciated that any variations in such thickness will be relatively great and effect the operation of the flattened wire when used as a cathode. This is particularly true since the wire, is used as a resistance eienient for flow of electrical energy and is susceptible to variations in its electrical conductivity if the dimensions of its cross sectional area varied throughout its length.

It is an object of the present invention therefore to provide an apparatus for avoiding the above mentioned difliculties and to produce a metallic ribbon core for use as an oxide coated cathode which will have a uni+ form cross sectional area to give the required resistance for operation with the desired voltage amperage characteristics at a given op erating temperature.

Another object of the invention is to provide a filamentary flattened core material having a uniform cross section at all points throughout its length.

Other objects and advantages of the invention will be more fully understood by reference to the following specification together with the accompanying drawings in which,

Fig. 1 is a side elevational view of a. machine embodying the present invention.

' Fig. 2 is an enlarged plan view of a portion of the machine shown in Fig. 1 partly in section to show internal structure.

Fig. 3 is a vertical section of the machine taken on line 111-111 in Fig. 2 and showing a power or driving unit. 7

Fig. 4 is a fragmentary view of a portion of machine showing an adjustable guide, an

Fig. 5 is a perspective view of a portion of a mount for an electrical device showing a flattened filamentary wire as used in practice.

A machine constructed in accordance with the present invention comprises a pair of pressure rollers having operative surfaces of substantially equal length and rotatable on parallel axes. The pressure rollers are arranged one above the other and are each en- .closed in a journal box. These rollers are provided with dressed or finished surfaces normally disposed in close relation to each other and each of the journal boxes is provided with a bearing surface area greater than one half the area of the operative dressed or lapped surface of a roller.

The lower journal box is supported in the bottom of a guide bracket and the'upper journal box is disposed within the upper portion of the guide bracket or hanger and tensionally held in position so that it may be moved toward the lower roller for contact therewith in the absence of any force due to the potential energy of the said suspended upper roller and its journal box, thus making it possible to adjust the rollers to an extremely accurate space relation for contact with a wire disposed therebetween without subjecting the wire to the weight of the upper rollers, means being employed for obtaining a micrometer adjustment for the rollers.

' For the purpose of avoiding the transmis-- sion of any inaccuracies from external mechanical driving elements which rotate the rollers they are coupled with a power unit by means of a loose coupling or lost motion connection. When the pressure rollers are rotated therefore, the desired extreme accuracy with respect to their space relation is maintained and the filament wire fed thereto may be compressed to an accurate cross sectional area, the dimensions of which will be held uniform throughout the length of the flat- I tened strip produced.

A practical embodiment of the machine may, as illustrated comprise a guide bracket 10 secured by bolts 11 to a bed plate or table 12. The bracket 10 may comprise

vertical side plates

13 and 14 disposed in spaced relation to provide a guide slot 15. A heador cross piece 16 is secured by tap bolts 17 to the upper ends of the

side plates

13 and 14 and within the guide slot 15 are disposed

journal boxes

18 and 19. j r

The rollers 21 and 22 are positioned in the

journal boxes

18 and 19 respectively and the journal boxes are at least equal in length to operative portions of the dressed surfaces 23 and 24 of the rollers. The length of the operative portions of dressed surface are indicated by arrows A in Fig. 3 and the journal boxes are provided with bearing surfaces 25 and 26 so formed asto provide a rounded slot be inserted into the journal boxes by being thrust into the slots endwise, a segment of each of the rollers projecting from the journal boxes for engagement with a wire 27 fed from aspool 28.

The journal boxes are arranged with the journal box 18' above the journal box 19. Thus the roller 21 constitutes the upper roller and is disposed with its axis of rotation above and parallel to the axis of rotation of the lower roller 22. A pair of tension members in the form of flat springs 29 and 31 are disposed between the journal boxes and serve to normally urge the journal box 18 upwardly and thus prevent the weight of the journal box and the roller 21 from being applied to the wire to be compressed between the rollers 21 and 22. For the purpose of adjusting rollers to a predetermined spaced relation, the head 16 is provided with micrometer threaded screws 32 which pass through threaded apertures 33 in the head 16. Graduated scales 34 and indicators or pointers 35'are provided so that as the screws 32 are rotated by engagement with nuts or heads 36 the journal box and roller may be given a predetermined degree of movement.

A shim 37 0f hardened material may be disposed between the journal box 18 and the lower end of the screws 32 so as to provide a replaceable surface when worn. It has been found desirable to provide the rollers with a' film of oil or lubricant and for this purpose an oil cup 38 is provided having a conduit 39 leading to a passage 41 which communicates with the dressed surface of the upper roller 21, so-that a film of oil may be carried around the rollers.

It is desirable to have a sight-feed for the oil so that trials may be made to obtain the proper amount or film thickness after which the valve may be set to give a continuous feed of the proper amount.

It is important when flattening a fine wire of the character operated upon by the pres-' These force screws pass through threaded apertures in the plate 14 and engage with the outer surface of the journal boxes. After the rollers 21 and 22 have been properly adjusted to the required spaced relation for the flattening of a wire, the

force screws

42 and 43 are manipulated and the journal boxes are compressed between the ends of the said screws and the side plate 13 sufficient force being applied to slightly spring the ournal boxes and more tightly compress their bearing surface in contact with the dressed surfaces of the rollers '21 and 22, thus providing the desired intimate contact between the dressed surfaces of the rollers and the bearing surfaces of the journal boxes.

The wire 27 ma be led through a guide 44 carried on an a justable support 45. The guide 44 may be of tubular form and preferably of some smooth material such as a vitreous coated metallic tube or of aglass tubular member, an end. 46 of which extends be-. tween the journal box and in close proximity to the oppositely disposed surfaces of the pressure rollers 21 and 22. The wire 27., after passing between the rollers may be collected on a spool 47 the said spool being mounted on a indle 48 carried in a bearing bracket 49.

above mentioned the entire length of each' of the pressure rollers is dressed or lapped and is effective for the flattening of a mm as shown in Fig. 4. The dressed surfaces of the rollers may be termed the operative pressure surfaces and the bearing surfaces of the journal boxes may be termed the efiective bearing surfaces. The wire to be compressed may be fed to any point between the operative pressure surfaces.

For the purpose of guiding the wire to a selected point the support of the guide 44 is secured toparallel strips 51 and 52 disposed at opposite sides of and beneaththe heads of tap bolts 53 and 54 which secure the strips in position and hold the guide in given relation to the rollers 21 and 22 by manipulating the screws 53 and 54. The support 45 may be adjusted with respect to the said rollers so that the wire may be guided into contact with different portions of the surfaces thereof as desired.

From the foregoing it will be evident that the rollers 21 and 22 are self contained insofar as the o eration of flattening a wire is concerned. l lach of the rollers is provided with a bearing surface of such character P that the roller is held accurately in position and the space relation between the rollers is constantly maintained.

When rolling a filament wire to the dimensions necessary for the production of a filament or cathode base, it is important that the pressure'rollers receive motion from a power unit without having their accurate relation disturbed by inaccuracies which might be translated through connection with the power unit. In the present construction the pressure rollers are therefore provided with ends 55 terminating in square headed shanks 56.

A link 57 and couplings 58 and 59 connect the shank of the upper roller 21 with a squared end 61 of a shaft 62 having thereon a gear wheel 63, suitably journaled in bearings 64 and 65. The gear wheel 63 is disposed in mesh with the gear wheel 66 secured to a shaft 67. An end 68 of the shaft 67 is provided with a sprocket 69 connected by a chain 70 the bearing surface.

with a motor or other suitable source of power, not shown.

An opposite end 71 of the shaft 67 is squared and connected by a link 72 with shank 56 of roller 22 by means of

couplings

73 and 74. The'link connection for the transmission of rotary motion to the rollers is of a flexible character or a lost motion connection so that the rollers 21 and 22 may be rotated without being subjected to any external force which might disturb their said space relation. The gears 63 and 66 which are mounted in a gear box -7 may be considered as a power unit.

For the purpose of preventing endwise movement of the pressure rollers stop plates 73, 74', 75' and 7 6' are provided. These stop plates engage with the shoulder atthe outer edge of the extended portions 55 of the rollers and serve to prevent end thrust.

For the purpose of rotating the spool 47 to gather the flattened wire the shaft 48 is provided with a pulley and a belt 81 con nects this pulley with a pulley 82 (see Fig. 3) secured to link 72 so that motion is translated to the shaft 48 and the spool 47 rotated and the flattened filament wound thereon.

When flattening wire of nickelor nickel alloy fine particles of material become loose and adhere to the-surface of the rollers.

It has heretofore been found that when flattening such wire this fine deposit of material tended to wear grooves in the rollers or otherwise destroy the smooth surfaces necessary for accurately flattening the wire.

In the present invention a number of pockets 77 are provided in the form of slots in The slots extend between ends of the bearing surfaces and during the rotation of the rollers the particles of material which adhere to the surface of the rolliirs are scraped off and deposited in...the

oc ets.

are provided they are only necessary should an excessive amount of material accumulate since it'has been found in practice that when supporting a pair of pressure rollers for rotation in the manner above described, the close relation between the rollers and the bearing surfaces attainable by the present construction, serves in conjunction with the particles of material which free themselves from the wire to continually lap or dress the surfaces of the rollers and maintain them Although the pockets above referred to -ot' the contacting wire, are smoothed out accuracies of the grinding wheel. The procedure of lapping by the usual machine shop practice results in a cylinder having the most accurate portion between its ends.

In the case of the present rollers the surfaces indicated as A are the true or operative surfaces and are disposed for rotation in the bearing surfaces and 26. The ends 55 of the rollers project from the bearing boxes but do not function as bearings. Thus the total bearing surfaces for the rollers consists-of the bearings 25 and 26 which are in contact with the operative or effective pressure surfaces A of the rollers 21 and 22.

By reason of the construction and arrangement of the journal boxes and the rollers, the rollers are self dressing since they intimately engage with the bearing surface of the journal boxes and inasmuch as the journal box bearing surfaces partly surround the rollers, a large area of contact is n'iaintained. By reason of the force screws 42 and 43 the diameter of the bearings may be changed and a more intimate contact between the rollers and the bearing surfaces may be attained which operates to provide not only an accurate bearing but a surface for dressing the rollers continuously while in operation.

Heretofore in machines wherein the usual pressure rollers were provided having their ends journaled in bearings the inaccuracies of the bearings were imparted to the rollers and accuracy, insofar as the dimensions of the flattened wire were concerned, was unattainable to the degree necessary in an article of the character to which the present invention relates.

In the present invention, however, where the operative pressure surface also constitutes the bearing surface of the rollers and where the rollers are rotated in a manner which may be considered independent of the source of power the required given spaced relation between the pressure surfaces of the rollers is maintained.

Practice has demonstrated that after long continued service the pressure rollers of a machine constructed in accordance with the foregoing description are free from surface irregularities which would otherwise tend to make inaccurate winding and that the close contact between the bearing surfaces and the effective pressure surfaces of the rollers serves to continually dress the rollers and any slight impressions that might be made by reason when a roller passes over its bearing surface. \Yhereas heretofore in other machines for flattening filament wire, it was necessary to cl'iange the rollers or shift'the' position of the wire frequently by reason of the groove v n'n in .he rollers by the passage of wire under compression.

The present machine has operated cont-inuously for a long time period without changing the position of the wire and without having its defective surface deformed in any way so as to effect the .production of flattened wire having the required dimensions in its cross sectional area through all portions of its length.

It will be readily appreciated that the present mechanism, since the upper roller is normally supported by the tension members the weight of the tension box and the roller, plays no part in the pressure applied to the .wire, and that the adjusting screws may adjustthe upper roller so that a given space relation is maintained between the upper and lower rollers, thus the applied pressure is uniform and if the wire Varies in its degree of hardness or softness, such variation will not affect the operation of the rollers in producing a wire of uniform thickness.

This. as hereinbefore. mentioned, is of extreme importance in connection with the forming of a cathode 84, as for example, that shown in Fig. 5, wherein the length and transverse cross sectional dimensions are of importance in determining the resistance of the cathode making it possible to meet manufacturing demands in the production of an electron emission device such as a radio tube having given voltage and amperage characteristics.

Although a preferred embodiment of the invention is shown and described herein it is to be understood that modifications may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is: i

1. A machine for flattening a filamentary wire comprising pressure rollers, dressed surfaces on said rollers, bearings partly surrounding said rollers, the total bearing surfaces of said bearings engaging said dressed surfaces of said rollers and means for changing the diameter of saidbearings to vary the degree of contact with said dressed surfaces.

2. A machine for flattening a filamentary wire comprising a pressure roller, a bearing partly surrounding said roller and means for changing the diameter of said'bcaring to vary the degree of contact between the bearing and said roller.

3. A machine for flattening a filamentary wire comprising a pair of pressure rollers, a journal box for each roller, bearing surfaces partly surrounding said rollers and vmeans for applying a lateral force to compress said bearing boxes to change the degree of contact between said bearmgs and said rollers.

4. A machine for flattening a filamentary wire comprising a. pair of pressure rollers, a journal box for each roller, bearing surfaces I partly surrounding said rollers and means for compressing said bearing boxes to change the de cc of contact between said bearin s and sand rollers and means for adjusting said journal boxes to change the relatlve position 6 of said rollers.

5. A machine for flattening a filamentary wire comprising a air of pressure rollers, a

' bearing box for eac roller, bearing surfaces partly surrounding said rollers and means for 10 adjusting said bearing boxes to change the relative positions of said rollers, and means for var ing the de ee of contact between said ro ers and sai bearin surfaces.

In testimony whereof, have hereunto v 15 subscribed my name this 5th day of July,

STEN WADSTEN.