US2408596A

US2408596A - Method of forming cylinder ends

Info

Publication number: US2408596A
Application number: US526253A
Authority: US
Inventors: Joseph J Bednar; Steven P Peck
Original assignee: National Tube Co
Current assignee: National Tube Co
Priority date: 1944-03-13
Filing date: 1944-03-13
Publication date: 1946-10-01
Anticipated expiration: 1963-10-01

Description

Def. *1, 1946. J; J. BEDNAR EI'AL ,40 6

METHOD'OF FORMING CYLINDER ENDS Filed March 13, 1944 '2 Sheets-Sheet l Oct. 1, 1946. J. J. BEDNAR EI'AL 2,408,596 METHOD OF FORMING CYLINDER ENDS- Filed March 13, 1944 2 Sheets-Sheet? 721545 Mal mi.

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Patented Oct. 1, 1946 2,408,596 I METHOD OF FORMING CYLINDER ENDS Joseph J. Bedna and Steven P. Peck, McKeesport, 2a., assig'nors, to National Tube Company, a corpora ion of. New J ersey Application March 13, 1944, Serial No. 526,253

2, Claims, (Cl. 29-1482) This invention relates to an improved method of spinning integral ends oncylindersto adapt them for high-pressure service.

Heretofore the spinning of cylinder ends has been quite definitely restricted touse on small cylinders suited only for low-pressure work. One object of the present invention is to provide a method for building up the thickness of an end section of a tube or cylinder which will adapt it for high-pressure service.

A further object isv to provide a method involving the building up of the end thickness of a cylinder by spinning and subsequently eliminat ing the fissure or feathers formed in the region of the original point of juncture of the end edges.

As will appear more fully hereinafter, our improved method involves spinning integral closed ends on tubular metal workpieces to form a closure capable of withstanding a pressure of 2500 pounds per square inch or greater, the method.

being characterized by rotating the workpiece while. applying a work-engaging tool to the end portion thereof, moving said tool through arcs 2 dition of the tube orcylinder and the difierent stages in the operation of the method.

Figure 7 illustrates a step in the method wherein the mid-portion of the built-up metal of increasedthickness is forced inwardly into engagement with a die member.

Figure 8 illustrates the step of removing feather-like portions resulting from the operation of Figure 7.

Figure 9 is a detail portion of an end of a cylinder made in accordance with the herein claimed method.

Referring in detail to the drawings, l0 represents a conventional form of chuck adapted to grip a tubular or cylindrical workpiece l2. This chuck is rotatably supported by a suitable spindle M of conventional form Which is rotated by any suitable means such as a belt l6 connected to a power drive (not shown). The chuck and its driving means are adapted to rotate the tubular workpiece I2 at a speed of approximately 1400 R. P. M. Mounted in juxtaposition with the extending from the periphery toward the longi- Y tudinal axis'of the workpiece, also moving the tool axially of the workpiece, to bring the end edges of said workpieceforcibly into abutment. in the region of the longitudinal'axis thereof,

' cry to a point beyond the longitudinal axis of the workpiece, so as to upset said end portion and thereafter continuing the movement of said tocl in arcuate paths extending from the periphand build up metal of increased thickness without a fissure outside the original point of juncture of said edges, then stopping the rotating and thereafter pressing the mid-portion of the closed end inwardly into engagement with a die memher having an axial recess opposite the point of juncture of said edges, whereby feather-like portions in the axial region adjacent said point of juncture are pressed into said recess, and thereafter removing said feather-like portions.

For a full understanding of the invention, reference should be made to the following detailed disclosure, the accompanying drawings, and the appended claims.

In the drawings:

Figure 1 is a plan view of conventional apparatus suitable for carrying out the present invention.

an initial step of the imchuck I 0 is a tool bed [8 having slidably mounted thereon a table 20 which canbe reciprocated back and forth by any suitable means in the direction lengthwise of the work.

A compound tool rest. 22 is pivoted at 24 at 1 a, point'ecccntri tothe longitudinal axis of the workpiece I2. The tool rest carries a slide 26 which supports a tool holder 2,8 carrying a tool 30 which is preferably, although not necessarily, in the form of a roller pivotally mounted in a bearing 32, so that the tool can make a, rolling contact with the end portion of the tubular workpiece l2. Prior to the operations about to be described, the end portion of the workpi ce will usually be locally heated, for example, by the impingement of flames from oxyacetylene torches such as indicated at 34 and 36. The torches are eifective to maintain the end of the workpiece at the optimum spinning temperature of approximately 2000 to 2200 F. The torch 36 is mounted adjacent the compound rest 22, and the torch 34 is mounted on any stationary portion of the apparatus.

In starting the improved method, after the work is properly heated, the tool 30 is moved to the position of Figure 2, where the leading edge of the periphery of the tubular workpiece is engaged. After such engagement the tool rest 22 is swung about its pivot 24; for example, from the position of Figure 2 to the position of Figure i3, through the arcuate path indicated by the dotted arc a:.y, the tool'at this time swinging about a radius r struck from the center 24 which,

as shown, is in plan and is offset from the longitudinal central axis of the workpiece [2.

The tool 30 is moved back and forth along its arcuate path several times, with the result that metal from the outer normally cylindrical portion is flowed inwardly, thus thickening the end region of the tubefrom the normal gauge of the workpiecetothe thickened condition suggested in Figure 3. Subsequent arcuate sweeps or the tool 3!] with an accompanying endwise movement of the tool toward the work gradually spins in the end of the tube'until it is substantially closed, as shown in r stroke of the tool 38 is then increased to the position such as suggested in Figure 5, thus completely closing the tube end and bringing the Figure 4. Ihe arcuate end edges initially into abutment in the irri'mediate region of the longitudinal axis of the workpiece l2. At this stage of the methodfithere will be present a fissure f in the zone of initial abutment of the end edges of the tube. Thereafter the tool 30 is given a plurality of additional arcuate sweeps to the position indicated in Figure 6, where the working face of the tool crosses the longitudinal axis of the end of' the workpiece. This is for the purpose of building up worked metal of substantial thickness without 'a-fis'sure, beyond the original point of juncture of the end edges. This condition is illustrated in Figure 6, wherein it is noted that the fissure ends at the'point j, and the metal beyond that point is entirely devoid of a'fissure and is thus rendered more dense so that it is thereby made capable ofwithstanding' considerable pressure.

Upon completion of the operation represented in Figure 6, the workpiece is removed from the chuck l and the end thereof is entered into the cavity 38 of a die 4!). Thereupon another die 42 having a central recess 44 therein is forced inwardly, withthe result that featherlike portions 46 located in the longitudinal central axial region "of'the' workpiece and flanking the central fissure, are forced inwardly into, the recess 44 of the die 42'. moved and the work-piece is disengaged from the die '42. The workpiece is then chucked in a suitable metal working tool such'as a lathe or the like, and a cutter bar 48 centered byaguide rest and carrying a spade or similar cutting tool 52 is brought into play, so as to machine Ifhedie 42 is then re solid section free from physical off the projecting feather-like portions which flank the fissure. At the conclusion of this operation the interior of the cylinder will have the finished face 54 and the exterior will have a dished cavity 56, as shown in Figure 9.

It will be understood that in the machine operation of Figure 8, the feathers 46 flankin the fissure .willbe eliminated. .Thus the end closure or bottom of the cylinder is a dense homogeneous defects and sumcient to withstand high commercial test pressures of the order of 2500 to 3500 pounds per square inch.

While we have shown and described precise operating steps, it is to be understood that the drawings and descriptive matter are to be interpreted in an illustrative rather than a limiting sense, since various modifications may be made within the scope of the appended claims.

We claim: 7

l, A method of spinning closed ends on tubular metal workpieces, comprising rotating the workpiece and applying a work-engaging tool to the end portion thereof, moving said tool through arcs extending from the periphery toward'the longitudinal axis of the workpiece, moving said tool longitudinally of the axis of the workpiece to bring the end edges of said workpiece into abutment in the region of the longitudinal axis thereof, and thereafter continuing the movement of said tool in-arcs extending from the periphery tothe point beyond'the longitudinal axis of the workpiece to upset said end portion and build upmetal of substantial thickness without a fissure outside the original point or juncture of said edges, stopping rotation of the workpiece, then extrudingthe axial portion of said closed end inwardly'into an axial cavityin a die memher in the'region of the point of juncture of said edges," said extruding step causing featherlike portions to be forced axially into said die cavity, and finally removing said axially extruded feather-like portions; I i

' 2; The method of claim 1, further characterized-- by the step of facilitating the upsetting operation bydirecting heat locally against the end. portion of the workpiece while actuating said tool to upset the end portion of the work.

JOSEPH J. -BEDNAR. STEVEN P. PECK.