US2568991A - Machine and method for closing metal tubes - Google Patents

Description

C. L. DEWEY MACHINE AND METHOD FOR CLOSING METAL TUBES 3 Sheets-Sheet 1 Sept. 25, 1951 Filed March 11, 1943 Sept. 25, 1951 c. L. DEWEY 2,568,991

MACHINE AND METHOD FOR CLOSING METAL TUBES Filed March 11, 1943 3. Sheets-Sheet 2 P 25, 1951 c. L. DEWEY 2,568,991

MACHINE AND' METHOD FOR CLOSING METAL TUBES Filed March 11, 1943 s Sheets-Sheet 5 12 flaw/76y,

Patented Sept. 25, 1951 MACHINE AND METHOD FOR CLOSING METAL TUBES Clarence L. Dewey, Elkhart, Ind., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application March 11, 1943, Serial No. 478,843

3 Claims.

The machine and method of the present invention are designed for the purpose of inturning and closing the ends of metal tube sections by a cold working process which will uniformly, accurately, and rapidly reduce, configure, and close the end of the tube section and meanwhile regulate the wall thickness thereof so that thereafter the tube section may be employed for the intended purpose.

In general, the method and mechanism, in the form hereafter described, involves the employment of a plurality of end-reducing rolls of special design which as shown are mounted and driven in such a way with relation to each other as to positively revolve and rotate around the end of a tube section which is held against rotation, but is fed inwardly in proper speed ratio to'the operation of the rolls, so that by a proper coordination of the feeding and reducing movements, the end of the tube will be reduced and ultimately closed and configured in the intended manner.

The formation of the acting faces of the rolls constitutes an essential feature of the present invention, and in order to subserve the intended purpose, the acting faces of the rolls are of tapered or concave configuration and provided with a multiplicity of longitudinally extending ribs or corrugations which preferably extend in divergent relation to the respective radial planes of the rolls, so that as the rolls are rotated and revolved around the end of the tube, a circumferential series of tangential impacts and pressure contacts will be maintained. By thus providing obliquely or spirally extending ribs with intervening grooves or valleys, the points of attack and impact upon the metal surface will be interspersed by intervening gaps which allow areas of clearance for the redistribution of the metal fibers and avoid the excessive compression of all portions of the metal surface which would result from the employment of smooth-surfaced rolls for a like purpose.

In order to fully disclose the nature of the present method and mechanism, reference is made to the accompanying drawings wherein- Figure 1 is a side elevation, partially broken away, of a machine embodying the principles of the present invention;

Fig. 2 is an end elevation looking toward the right-hand end of the machine in Fig. 1;

Fig. 3 is a cross-sectional View taken on line 3-3 of Fig. 1, showing the clamp for fixedly holding the tube section;

Fig. 4 is a cross-sectional view taken on line 4-4 of Fig. 1;

Fig. 5 is a longitudinal sectional view taken through the center of the machine;

Figs. 6, '7, 8, 9, 10, 11, and 12 are a seriesof views showing the ends of tube sections of varying configuration and illustrative of like changes which may be made in the configuration of the rolls; and

Fig. 13 is a diagrammatic view on a substantially enlarged scale, showing in full lines the tangential impacting action between successive ridges or ribs of the rotary tools or rolls and the peripheral surface of the tubular work, at the beginning of a reducing operation; and showing in dotted lines, the said ridges or ribs, which subsequently engage the peripheral surface of the work in circumferentia lly spaced and successively lengthened tangentially directed impacts as the tubular work is reduced.

In the present embodiment of the invention, the working portions of the machine are mounted upon a base 20 which may be extended to the degree desired to, accommodate the extended lengths of tubing. Upon the base is slidably mounted a clamp-carriage block 2| which may be advanced by a plunger 22 suitably operated by hydraulic or similar means not shown. The clamp-carriage block in its upper surface is provided with a groove 23 which coacts with a grooved face 24 of a clamping jaw 25 having a plunger 26 which may be operated hydraulically or otherwise to rigidly clamp the tube section.

The tube section near its inner end is entered through a centering ring 21 carried by a fixed standard 28 having a head 29 which surrounds the ring, which latter is fixedly held in position by a set screw 30. The centering ring and clamp in conjunction with one another serve to hold the inner end of the tube in position to present its axis in coincident relation to the axis of revolution of a pair of oppositely positioned rolls 7 3| whose peripheries stand in extremely close relation to said axis, so that as the rolls are revolved around the end of the tube and concurrently rotated, the adjacent peripheries of the rolls will in unison present a substantially continuous working contact with the marginal wall around the end of the tube.

Each of the rolls is keyed upon the reduced forward end 32 of a spindle 33 which has keyed thereon a spur pinion 34, the teeth of which mesh with the teeth of the internal gear ring 35. Each of the spindlesv is mounted within spaced ballbearing assemblies 36 and 31 separated by a spacer ring 38 housed within a cavity in a head 39 having inturned flanges 40 which bear against the ball-bearing assemblies 36, which flanges are sealed by packing rings 4| secured in place by caps 42. The rear end of the head 39 is closed by a disc 43 carried by a driving spindle A l, which disc is secured to the head 39 by bolts 45, so that the rotation of the driving spindle will impart rotation to the head 39 and cause the roll spindles and rolls to revolve around the axis of the driving spindle as a center.

The driving spindle is mounted within spaced ball-bearing assemblies 48 and 41 separated by a spacer ring 48 mounted Within a frame block '49. closed at its rear end by a cap plate 59 held in place by bolts The rear bearing assembly 4 is held in position by contact of the cap plate 5. in conjunction with a flanged collar 52, held in place by a nut 53 threaded onto the driving spindle, and the parts are sealed by a packing ring '54 held in place by a flanged cap 55, thus permitting the bearings to be adequately lubricated.

The reduced outer end 56 of the driving spindle has mounted thereon a grooved pulley 51 which imparts rotation to the spindle.

The formation of the acting faces of the ribs or ridges'of the rolls is best illustrated in Figs. 1, 4 and 13, and this formation and operation of the ribs constitutes one of the more important features of the present invention.

For purposes of illustration, concavely faced rolls are shown in these figures, which in conjunction are designed to impart to the end of the tube the hemispherical closure shown in Fig. 5, but it will be understood that the configuration of the acting surfaces of the rolls may be of other formations, complimentary 'to the shapes illust-rated-in Figs. 6-12 inclusive and that such variations, or others of a like or similar character, are regarded as within the range 'of the present invention.

The rolls shown-in Figs. 1 and 4 are of enlarged diameter at their inner ends and progressively reduced therefrom toward their outer ends which first make contact with the incoming tube section. The roll face is provided with a multiplicity of spaced ribs or ridges 58 and intervening valleys 59 which alternate with one another in'uniform sequence throughout the face of the roll. The ribs while extending in a generally longitudinal direction trail backwardly and flare outwardly in oblique divergent relation to' respective radial planes through the tips of the ribs and are preferably of arcuate formation extending spirally as shown although they may for somepurposes be planate, and it will be understood that the term oblique" as here employed is intendedto cover any equivalent departure, whether arcuate or planate, from a truly radial arrangement.

The flaring out of the ridges toward the rear may be by an unbroken uniform curvature as shown in Fig. 5, or by variations in curvature as in Fig. 8, or by curvatures which in conjunction give the pointed-arch formation of Fig. '7, or the flattened center formation shown in Figs. 6 and 11. Fig. illustrates a truly conical formation in which the rib surfaces present themselves in straight line contact to the tube surfaces, and it will be understood that numerous combinations or variations of such formations may be employed without departure from the spirit of the present invention.

It will be noted from an inspection of Fig. 4, and the enlarged diagrammatic showing in Fig.

13 with due regard to the arrows indicating the direction of revolution and rotation that the ridges of the rolls currently occupying the upper and lower positions as shown both extend obliquely or in divergent relation to the radial plane which includes the points of tube compression although the rolls occupy opposed positions to the tube surface, and both rotate in clockwise direction as they revolve within the gear ring 35 in a counter-clockwise direction about the centrally disposed tubular work.

With particular reference to the diagrammatic illustration in Fig. 13, it will be seen that by the provision of the obliquely disposed, circumferentially spaced rounded ridges, the tips of the ridges will in succession, first forcibly engage and tangentially impact the tube wall at a plurality of progressively advanced and symmetrically disposed points therearound, at the free end of the tube, at the beginning of a reducing operation. Thereafter, as the diameter of the tube end is reduced, further points on the obliquely disposed ridges will successively tangentially impact the tube wall at circumferential points, i. e. the progressively advanced points of impact with the tube wall are closely spaced therearound, and as the tube is reduced in diameter a greater length of each ridge will come into operative engagement with the tube wall and travel spirally of the tube outwardly from the point of maximum diameter of the tube to the reduced end thereon.

As indicated in Fig. 13, one of the ridges 58 is shown in point contact with the tube wall at the beginning of a reducing operation, and the ridge is shown in dotted lines as observed from the transverse plane of the tube at said-point of contact and toward theend of the tube when same is fully reduced and-closed.

The concentric broken lines a, b, c, 11 indicate diagrammatically successive planes lengthwise of the tube in the progress of reduction thereof. Since the ridges have the same curvature as the finished end of the tube (Fig. 5), the central ridge in Fig. 13 will successively contact the tube end as a tangential impact further and further from the initial point of contact indicated in full lines, for instance to the point a on the ridge when the tube end 'has been reduced to the plane of the circle a, and when the tube has been reduced to the plane of the circles bcde the successiveridges will contact the wall thereof continuously from the point of initial operation to the respective points b, 0, etc.

Since the rolls revolve around the tube, the right hand ridge indicated in Fig. 13 will contact the tube to the left of the previous contact of the central ridge, or substantially at the point of tangency of arrow f with the tube wall, and successive ridges will contact the tube at the points ofntangency of arrows g, h, and so on around the circumference of the tube at slightly spaced points, as explained above.

As seen in Fig. 4, each roll 31 will rotate through 720 for each complete rotation of the head 39 through which rotation the rolls will be carried around the tube, and since each roll has, as shown, 16 ridges, the tube wall will. receive 64 tangential impacts in any transverse plane of the end being reduced, and due to'the revolution of the rolls around the tube together with the continuously reduced diameter of the tube toward the final closed end thereof, successive impacts by the respective ridges will be at differently spaced points circumferentiallyof the tube, with the result that no lines of impact will appear on the wall of the finished closed end of the tube. In short these line points of impact and contact will progress obliquely. or spirally with respect to the tube surface, so that at no instance will the ribs present an extended lateral contact with the tube, the ribs being rounded on their tips so that but a slight departure from a truly point contact at any time is presented. Such slight departure is due to the current advancement of the tube as the crest of anengaging rib tangentially impacts and'moves across the surface and efi'ects at each instant a reduction in diameter by the minute area of contact currently afforded.

This reducing action due to the revolution of the rolls will be speeded by the rotationof the 7 rolls themselves so that the direction of rearward travel of the compressive impact points and contact lines against the tube surfacewil] be the resultant of a number of factors including the speed of revolution of the rolls, the speed of rotation of the rolls, the obliquity or spirality of the ribbing, and the feeding speed of the tube itself. Since it is possible to vary all of these factors with relation to one another, it is evident that the flow of the metal may be regulated to best meet any set of conditions encountered.

The reduction thus proceeds by the displacement of minute quantities of metal which are thus permitted to redistribute themselves freely and without excessive confinement so that galling or abrasion of the metal surface is avoided and the reduction proceeds by minute stages which, however, by reason of the speed at which the rolls may be revolved will be sufliciently accelerated to permit the operation to proceed rapidly, accurately, and with precision, so that uniformity of the resulting production is ensured by a proper timing of the operations.

By giving to the ridges the proper obliquity with relation to the direction of rotation of the rolls, each ridge attack and impact will be first centered against the forward peripheral wall of the open end of the tube so that the progressive impingements of the ridges around the tube will be generally and inwardly therefrom with the result that at all times the metal will be crowded metal in the same direction and counter to the s.-

rotation of the rolls.

As the tube is advanced, its ends will be worked in or crowded toward the center and progressively thickened until complete contact is established with the inner base ends of the ridges which oppose each other from opposite sides of such close adjacency as to effect complete closure of the tube and thereafter, if desired, the tube may be further fed inwardly which will additionally thicken the closed tip of the tube to any desired degree.

In cases where it is not desired to completely close the end of the tube, the feeding may be terminated before complete closure results, or the rolls may be spaced apart sufliciently to provide a gap or clearance through which the tip end of the tube will be projected in the form of a reduced nose or extension of the character shown in Fig. 12 which may be completely or partially closed.

Although for purposes of illustration I have illustrated the employment of two oppositely disposed rolls whose axes occupy the. same plane of compression which intersects the axis of the tube, it is evident that where close adjacency of the rolls. and complete closing of the tube is not re,- quired, a group of three or more rolls might be employed, in which case angularly related planes of compression around the tube axis would be presented so that where reference is made to the plane of compression, it will be understood that this term does not necessarily signify asingle plane which includes the axes of all of the rolls comprising the group.

It will also be understood that the term point contact as applied to theattack and/or impact of the ridges against the terminal surface of the tube wall is not intended to be limited to a mathematical point but is intended to refer to a limited surface approximating a point as distinguished from a broad-side engagement of the entire crest of the ridge against the surface'of the tube.

It will also be understood that the term shoulders as applied to the surface of the tube has reference to the slight elevations against which the attack of succeeding ribs are directed, which shoulders are constantly recedingunder the successive attacks of oncoming ribs. The cumulative effect of repeated recessions is to reduce the tube by stages and until final closure is effected.

The process of the present invention is one which is adapted for the reduction and endclosing of tubes of varying metallic character and within a wide range of gauges and diameters, and although it is well adapted for the cold rolling of steel or other tubing of moderate diameter and gauge, it may be desirable in certain instances to heat the tube section in advance of the reducing operation, especially where a tight welded closure is desired.

Furthermore, the desirability of preliminarily heating the tubes will depend upon the use intended and the nature of the configuration and wall thickness to be imparted to the resulting product so that variations in this regard are deemed to be within the knowledge of mechanics skilled in the art and having in mind the most desirable speeds of revolution and rotation of the rolls in relation to the advance of the tubing.

The configuration of the acting surfaces of the rolls is one which is intended to reduce any abrasive action and resultant heat from friction to a minimum, so that in cold reducing operations only a moderate amount of heat will be developed, though ordinarily it may be desirable to employ proper lubricants or cooling agents of the character commonly employed in operations of this general character.

Although it will be desirable in most instances to revolve and rotate the rolls around a non-rotating tube and to advance the tube relatively to the rolls, a reversal of one or both of these relationships between the tube and rolls is contemplated so that in the claims, unless otherwise indicated, it will be understood that relative rather than absolute movement of the parts is intended.

I claim:

1. The method of inturning the ends of metal tubing which comprises simultaneously subjecting the exterior wall of the end of a tube to be inturned at a plurality of progressively advanced symmetrically disposed points to tangentially applied impacts, the impacts progressively lengthening. axially of thetube'as the diameter or the tube is reduced. 7

2. The method ofi inturning-theendsof metal tubing which consists :in. simultaneously subject ingthe exterior wall of theend 01 a tube to be inturned at a plunality oi -progressively. advanced circumferentially spaced points to tangentially applied impacts, the impactsprogressively-lengthening axially of the tube as the diameter thereof is reduced, and the lengthening impactsextend-- ing obliquely to the axis oi the tube-from: said points.

3. In a machine for inturning the ends of metal tubing, a plurality of elongated reducing-rolls of generally circula-r cross section having working facw contoured to impart: the desired inturned shape to a tube end and arranged to define a gradually converging-opening or roll: passto receive the end of the tube, saidfaces each beingprovided with a series of 'circumferentiallyspaced blunt ridges each extending somewhat longitudinallyof the tube and at an oblique ang'le to the adjacent axial plane of the tube through the contacting'ridge andfunctioning to exertsequentially engaging, spaced, progressively advancing reducing point impacts on the tube wall without chatter and resultant mutilation when rotated each on itsown axis, a rotatably mounted REFERENCES CITED The following references are. of record in the file of.this patent? UNITED STATESPATENTS Number Name Date 172,443 Ide Jan. 18, 1876 1,280,823" 'Oster Oct. 18, 1918 1,368,413 Stiefel; Feb. 15, 1921 2,234,182" Lauer Mar. 11, 1941 2,325,522 Lauer'et al July 2'7, 1943 FOREIGN PATENTS Number Country- Date 19,420 Great Britain of 1909 486,543 France Jan; 21, 1918 539,991 France Apr. 10, 1922

Images