US1644823A - Method of making metallic bellows - Google Patents

Description

' 1,644,823 fiat, E1, 1927. 1 H. B. FAY

METHOD OF MAKING METALLIC BELLOWS Filed Oct.28, 1924 Horace ESFQy ATTO NEYS 1,644,823 UNITED STATES PATENT OFFICE.

HORACE B. FLY, OI SEAKEB-HEIGHTS, OHIO.

Patented Oct. 1 1, 1927.

mnrnon or minim un'rmro minnows.

Application filed October 28, 1924. Serial No. 746,881

'I of making deeply corrugated, flexible,

The present invention relates to a method tubular metal walls or metallic bellows, and more particularly to an improved method of making such bellows by combined mechanical and fluid pressure operations to produce a superior bellows and one having substantially uniform wall thickness and temper throughout each portion of the corrugation.

- constituting, however, but

- plications of the principles of my invention.

through "j has the disadvantage o.

by my improved method. I

In said annexed draw1ng: a

1 is a longitudinal central section a tube showing co-operative rolls in position to forma partial corrugation in the wall of such tube; Fig. 2 is a longitudinal section showing one wall ofa tube after formation into corrugations by means of a collapsible die; and Fig. 3 is a longitudinal section through aportion of bellows formed Fig.

, Metallic bellows may be manufactured either by rolling corrugations into the wall of the tube or by expanding the wall of a tube by fluid pressure exerted within the tube to produce externally extending corrugations,

or by a combination of these two methods in which the corrugations are first partially formed? in the tube 'wall' by fluid pressure.

"and are then brought to their'final form by mechanical operations, such as rolling. The

last-named roces's, th at is, the'combination P which inclu es fluid pressureexpansi'on followed by'mechanicale ansion or rolling,

method, which is that tiny'particles of grit cling to the surface, eith'e'rpf-the rolls or of the tube," and are'lrolledtinto the tubewall duringfthe "rollin i make the tube wea operation, tending to p at that point and l able to l)refalm'ge when" any."-extreme-pressure is 'applieditoit. 1

esista'njcef of the" bellows is "tested during heir formation} that is, the ressure neces= he tube wa .into corrugat me T e y higher than ny p sets given to. the bellows axis of the tube.

1 the usual rolling "f'lhe one"articular advantage of bellows made by a uid' pressure process is that the which is ap lied, to the corru ations in actual service ater, and also in t e fluid pressure method there is no possibility of grit becoming embedded in the wall of the corrugations and weakening these walls.

The principal object of the present invention is the provisionof a method which will combine the advantages of both the mechanical and fluid pressure methods, while retaining all of the advantages and characteristicsy the fluid pressure method, which are the economy of manufacture, the testing of the bellows during its final formation under high. pressure, and the uniform stretching of the metal in each' corrugation, which tends to make the corrugations of uniform strength and resilienc I make my improved bellows by first su jecting a relatively thin tubular wall to the' mechanical action of co-operative rolls disposed on opposite sides of the tube wall, as shown in ig. 1. wall 1 is mounted between a pair of rolls 2 and an opposed roll 3, the rolls 2 and 3 being movable toward and away from each other. In operation the tube is first positioned over the rolls 2, after which either the tube, containing the spaced ,rolls 2, is moved toward the roll 3 or the roll 3 is moved up against the wall of the tube op 0- site to the space between the rolls 2, an is thus caused to form an encircling groove or corrugation 4 in the tube wall.

A series of corrugations is formed in the In this figure the tube rugat ions being equall s aced and bein of course parallel: and al right. angles to the The tube, with its inwardmay then be extions to provide complete exteriorly an interiorly extending corrugations by. the application of fluid pressure within the tube, while suply extending corrugations anded between these corru porting the previously formedcinward cor- ,rugations against expansion, This .operation may be performed in apparatus of the character described and claimed in the patent to F. K. Bezzenberger, No. 1,506,966, dated September2, 1924, in which a tube'is dis (1 within a partible die, eachhalf of which includes a series which, in the closed pletely encircle and enga a of thetubev In- Fig. 2 I ave shown a tube wall. provided th inwardly extendmg' c mmons 4 e dle rings 5 tion of the die, comgainst the wall of half ringsor dies and 6 of the ty e shown in the above-named patent. In this case, however, the rings 5 and 6 are constructed to enter and engage snugly against the previously formed inner corrugations. After the tube has been so disposed within the die rings fluid pressure is exerted within the tube and acts to expand the portions of the tube wall lying between the rlngs outwardly, while at the same time an increasin pressure is applied longitudinally of the tube to colla se the same, the rin s being collapsed or rought together at t e same time so that the outwardly extendingscorrugations which are in process of formation are concluded a ainst the rings 5 and 6, which, at the finish of the operation, are in the relation shown in Fig. 2 at the upper part of the figure. In this way the entire corrugation is formed, each corrugation consisting of the previously formed inner portion 4 and the outward portion 7, the corrugations having parallel radial ortions 8.

In roducing a bellows. in t is manner it shoul be remembered that there may be not only a stretching of the metal produced by increasing the length of that portion of the tube measured longitudinall which is being corrugated, but also that this ortion of the tube wall is being stretched a so b the increase in diameter, that is, there is both a longitudinal and a circumferential stretch given to the metal. It will be apparent that the circumferential stretch .will be difi'erent when the corrugations are thrown inward" and the diameter reduced from the stretch imparted to a corrugation which is thrown outwardly, and I so proportion the initially formed inward corrugation and the subsequently formed outward corrugation that the stretch which is thus given to the metal is substantially the same, which will provide a uniform temper in both the crests of theinner and outer corrugations. The temper in the metal in the radial planes 8 is also substantially the same as thatat the'crests of the corrugations, since in a bellows made by a single fluid pressure operation, it has,

been found, the metal will flow and the stretch will be distributed throughout the en-' tire corrugation very much more evenly than is possible when a tube wall vis corrugated between rolls which merely stretch the portion of the metal lying between the crests of the spaced rolls.

The distribution of metal from the two o rations is shown in an exagerated way in i 3, in which the'thickest portion of the wal of the corrugation is at the points 9,

4 which correspond to the points -10in the. tube in the condition shown in Fig. -1. The wall bellows by the resent method to prevent any increase, in tie surface length of the bellows measured along a line lying on the surface of a tube or bellows and disposed arallel with the axis of the same, as it has een found that if the tube is materially lengthened in this dimension this lengthening is produced by undue stretchin of the metal inthe outer corrugations, whic would impart too great hardness and temper to the walls at these points and cause their early breaka e. It-will of course be apparent that in the initial mechanical step of the resent method the tube length is. increase .somewhat, and it is therefore desirable to actually shorten the tube length in the fluid pressure operation by an amount which substantially equals the increase in the, first operation.

By the present method bellows having ver deep'corrugations may be made, since -di erent portions of the metal wall are the corrugation, that is, the metal is at no point stretched as much as is the case when the corrugation is formed entirely outwardly, {gas is the case of bellows made by a single uid pressure expansion). In the first step ofmy method the metal may be stretched inwardly an amount producing the maximum safe working temper in this portion,

say 20% to 40%, after which other portions of the tube are stretched outwardly until the same maximum temper is there present, but in this second operation the previously stretched or tempered metal of the inner portion of the corrugation is not again stretched or subjected to any tempering action. The .obvious advantage of thi; method is the a plication of the fluid pressure method to t e production of deep, evenly tempered corrugations which is a ty of corrugation not otherwise possible wit use of 'a uid pressure operation, at least without subiequent rolling operations with the risks of introducing imperfections into the metal wall.

The advantages of the present product are the uniformity of the wall thickness and temper throughout the entire area of each corrugation, and the consequent longer life of the bellows in service, together with the fact'that as the bellows is finished in a fluid ressure operation, which involves the estabishment of a relativel' high pressure with- ".in the bellows,it is t us possible to automatically test each bellows during its manufacture, and any bellows which will withstand this pressure will of course withstand the same or lower pressures in service. In

. addition to this advantage the completion of the bellows. in a fluid pressure 0 ration avoids an possibilit of mechanic yworking into t e walls 0 the corrugations rticles of grit whichwould reduce thic ess at\these points and tend to shorten the life ito of the bellows and-its resistance'to leakage at high pressures. A still further advantage of the present method over the rolling method, which is most commonly practiced, is that it avoids the danger of, either cutting through or materially reducing the thickness of the tube wall at the crests of the corrugations, which has been a common cause of failure with bellows manufactured by mechanical or rolling methods. I

Other forms may be employed embodying the features of my invention instead of the one here explained, change being made in the form or construction, provided the elements stated by any of the following claims or the equivalent of such stated elements be employed, whether produced by my preferred method or by others embodying steps equivalent to those'stated in the following claims.

I therefore particularly point out and distinctly claim as my invention 1. Ina method of making metallic bellows, the steps which consist in forming spaced inwardly extending shallow grooves in a cylindrical metal wall. and then expanding such wall outwardly between such grooves by the application of pressure uniformly against the surface of said wall while supporting the outersurfaces of such grooves against expansion.

2. In a method of making metallic bellows, the steps which consist in forming spaced inwardly extending shallow grooves in a cylindrical metal wall, and then applying an internal fluid pressure against such wall while supporting the outer surfaces of such grooves against expansion.

3. In a method of making metallic bellows, the steps which consist in forming spaced inwardly extending corrugations in a cylindrical metal wall, and then applying an internal expansion fluid pressure against such wall while supporting the outer surfaces of said inwardly extending corrugations against expansion during the expansion of the wall portions between said firstnamed corrugations.

4. In a method of making metallic bellows, the steps which consist in forcing spaced'portions of a tubular metal wall inward to an amount *inducing the maximum safe working temper in the crest of the corrugation thus formed, and then expanding the tubular wall between said first-named inner corrugations by the application of fluid g pressure to form outwardly extending corrugations. between said first-named inner .g

corrugations.

5; In a method of making metallic bellows,

the steps which consist in forcing space portions of a tubular metal wall inward to form inwardly extending corrugations therein, and then expanding the wall outwardly between such internally extending corrugations by the application of fluid pressure within such tubular wall to an amount inducing the maximum safe working temper in the crests of the outer c'orrugationsthus formed, v

6. In' amethod of making metallic bellows, 'the steps which consist in forcing spaced portions of a tubular metal wall inward to an amount inducing the maximum safe working temper in the crest-of the corrugation thus formed, and .then expanding the wall outwardly between such inwardly extending corrugations by the application of fiuicl pressure to an amount inducing the maximum safe working temper in the crests of the outer corrugations thus formed.

7. In the method of making metallic bellows, the ste s which consist in forming spaced inwar ly extending shallow corrugations in a cylindrical'metal wall, and then expanding such wall outwardly between such corrugations by the application of pressure against the surface of said wall.

8.- In a method of making metallic bellows, the steps which conslst in forcing spaced portions of a tubular metal wall in ward to form inwardly extending corrugations therein, and then expanding the tubular wall between Said first-named inner corrugations to form outwardly extending corrugations between said first-named inner corrugations.

9. The process of making bellows consisting in providin a'tube of thin metal, forming aseries 0 inwardly pressed spacediii li l;

apart annular grooves in and around said tube with connecting sections of said tube between said grooves, and then acting upon said grooved tube to form it into a flexible longitudinally expansible and contractible bellows.

10. The process sisting in providing a plain elongated tube havin a thin wall, rolling a series of space -apart inwardly extending annular grooves with unworked and unchanged connecting sections of said tube between the grooves havin the diameter of said tube, and then wor in said connecting sections to form outwardI from said connecting sections.

11. The process of making bellowsconsisting in providing a lain elongated "tube havin a thin wall, orming a series of spaced-apart inwardly extendin annular ooves therein with uncorrugate connectsections of said wall between the ves, and then subjectingl sald connectmg sections to operations 12. The process of making bellows consistingin providing a tube of thin metal, forming a series of inwardly pressed spaced-apart annular grooves in and around extending corrugations of making bellows conich form outwardly extending corrugations. from said 1 connecting sections.

said tube with connecting sections having the diameter of the tube between said inwardly pressed grooves, and then forming said connecting sections into outwardly extending corrugations.

13. The process of making bellows consisting in providing a thin walled metal tube, rolling the metal of the tube inward to form grooves with connecting portions having the same diameter as the tube between said grooves, and forming said connecting portions into outwardly extending corrugations while enlarging the diameter of the same. I

14. The process of making bellows consisting in providing a thin walled metal tube, rolling a consecutive series of spacedapart grooves inwardly in said tube toward the axis of the tube with unworked connecting portions of the tube between said.

grooves which are connected by sections having substantially the same diameter as the original tube, and then working said connecting sections outwardly to form outwardly extending corrugations.

Signed by me, this 25 day of October, 1924.

HORACE B. FAY.

DISCLAIMER 1, 644,-823.-Horace B. Fay, Shaker Heights, Ohio. Mm'rnon or MAKING Mn'ranmc BELLOWS. Patent dated October 11', 1927. Disclaimer filed October 17, I 1935,-by the assignee, The Fulton Sylphon Company I Hereb enters disclaimer to that part of the claims in said specification which is inthe f0 owing words, to wit:

1. In a method of making metallic bellows, the steps which consist informing spaced inwardly extending shallow grooves in acylindrical metal wall, and then expanding such wall outwardly between such grooves by the application of pressure uniformly against the surface of said wall whilesupporting the outer surfaces of such grooves against expansion. v 1 2. In amethod of makinglmetallic bellows, the steps which consist in forming spaced inwardly extending sha owgropves in a cylindrical metal wall, and then applying aninternal fluid pressure against such wall while supporting the outer surfaces of such grooves against expansion.

3. In a method of making metallic bellows, the-steps which consist in forming I spaced inwardly. extending corrugations ina cylindrical metal wall, and then'applying an internal expansion fluid pressure against such [wall while supporting the outer surfaces of said inwardly extending corrugations aga nst expansion durmg'the expansion of the .wall portions between said first-named corrugations.

7. In the method of making metallic bellows, the steps which consist in forming spaced inwardly extending shallow corrugations in a cylindrical metal wall, and then expanding such wall outwardly between such corrugations by the application of pressure against the surface of said wall. 1 In a methodof making metallic bellows, the steps which consist in forcing spaced portions of a tubular metal wall inward to forminwardly extending corrugations therein, and then expanding the tubular wall between said first-named inner corrugations to form outwardly extending corrugations between said first-named inner corrugations. v 9. The process of making bellows consisting in providing a tubeof thin metal, forming a series of inwardly pressed spaced-apart annular grooves in-and around said tube with connecting sections of said tube between said grooves, andthen acting upon iaild grooved tube to form it into a flexible longitudinallyexpansible and contractible eows. 1

10. The process of making bellows consisting'in providing a plain elongated tube having a. thin wall, rolling a series of spaced-apart inwardly extending annular grooves with unworked and unchanged connecting-sections of s'a'id tube between the grooves having the diameter of said tube, and then working said connecting sections to 'form outwardly extending corrugations from said connecting sections.

11. The process of making bellowsconsisting' in'providing a plain elongated tube having a thin wall, forming a series of spaced-apart inwardly extending'annular groovestherein with uncorrugated connecting sections of said wall between the grooves, and then subjecting said connecting sections to operations which form outwardly extending corrugations from said conne'c ting sections.

12. The process of making bellows consisting in providing a tube of thin metal,

forming a series of inwardly pressed spaced-apart annular groovesin and around. said tube with-connecting sections having the diameter of the. tube between said inwardly pressed grooves; and then forming sald connecting sections into outwardly extending corrugations.

13. The process of making-bellows nonsisting in providing athin walled metal tube, rolling the metal of the tube inward to form grooves with connecting portions having the samediameter as the tube between said grooves, and forming said connecting portions outwardly extending'corrugations. hile enlarging-the diameter of the same.

" [Qfic'ialGazettc November 12, 1935.].

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