US2604138A - Tool for winding radiating fin on pipes - Google Patents

Description

July 22, 1952 A. J. HARRISON TOOL FOR WINDING RADIATING FIN ON PIPE 9 Sheets-Sheet 1 Filed Aug. 15, 1947 J Am cffianzi ivw h\ W O O O gfix N mm Q \QW. a. I fi W- aw. n I fl/ll u I o JM \w u m a ww J i NN 1|- FP E I I I I I I I l1 O m QM, WW R Q 0.. mm Q R \w July 22, 1952 A. J. HARRISON 2,604,138

TOOL FOR WINDING RADIATING FIN ON PIPE Filed Aug. 13, 1947 9 Sheets-Sheet 2 July 22, 1952 A. J. HARRISON TOOL FOR WINDING RADIATING FIN ON PIPE 9 Sheets-Sheet 5 Filed Aug. 13, 1947 737 flivza/ (f. erm 301$ gay W/fim 22, 1952 A. J. HARRISON 2,604,138

TOOL FOR WINDING RADIATING FIN 0N PIPE Filed Aug. 15, 1947* 9 Sheets-Sheet 4 cfflar12a5'a% jy iz' 4422271 5 War/saw July. 22, 1952 A. J. HARRISON TOOL FOR WINDING RADIATING FIN ON PIPE 9 Sheets-Sheet 5 Filed Aug. 13, 1947 A. J. HARRISON 2,604,138

July 22, 1952 I TOOL FOR WINDING RADIATING FIN ON PIPE 9 Sheets-Sheet 6 Filed Aug. 15, 1947 @MAZZF 5 Wat/55W y 22, 1952 A. J. HARRISON 2,604,138

TOOL FOR WINDING RADIATING FIN ON PIPE Filed Aug. 13, 1947 9 Sheets-Sheet v Hg. 9 Z7 J y 22, 1952' A. J. HARRISON 2,604,138

TOOL FOR WINDING RADIATING FIN ON PIPE Filed Aug. 13, 1947 9 Sheets-Sheet 8 y 22, 1952 A. J. HARRISON 2,604,138

TOOL FOR WINDING RADIATING FIN ON PIPE Filed Aug. 13, 1947 9 Sheets-Sheet 9 Patented July 22, 1952 TOOL FOR, WINDING RADIATING FIN ON PIPES Alma J. Harrison, Philadelphia, Pa., assignor to Proctor & Schwartz, Inc., Philadelphia, Pa., a corporation of Pennsylvania,

Application August 13, 1947, Serial No. 7 68,323

9 Claims. 7 1

This invention relates to apparatus for winding a continuous strip of thin metal edgewise around the circumference of a cylindrical member such as a tube or bar, and more particularly is directed to the winding head of such as apparatus.

Finned tubes of this general construction are Widely used in connection with driers and heat exchangers, and it is, therefore, important that good contact be made between the fin and the tube in order to produce eflicient heat transfer from the tube to the fins and vice versa.

Finned tubing made in accordance with the invention is characterized by a leg, a term applied to the fin proper, which extends radially at right angles to the axis of the tube. The inner edge of the fin is rolled at right angles to the leg to form a foot which tightly encircles the tube. Depending upon the use to which the tubing will be put, the foot may extend axially of the tube the entire distance between adjacent legs, or a gap between the foot spirals may be provided in order to reduce the thickness of metal through which the heat must be transferred.

Although many machines and methods of fabricating spiral finned tubing have been proposed, I am aware of no machine which, for example, enables the application to 1%" pipe, of spiral fins /2" in width. Narrow fins have been applied by one means or another but invariably when greater efficiency through larger radiating surface has been attempted, the stresses set up in the fin as it is wound on the tube have been so great that no successful commercial production of this type of tubing has been possible. These stresses have in the past prevented the production of a smooth spiral fin characterized by the complete absence of corrugations in both the leg and the foot, as well as the total absence of splits and it is specifically the ability to produce such an improved product that renders the present machine'a notable advance in the art. Furthermore, the'apparatus permits the use of steel fin material in place of the more expensive but more ductile copper or brass. Nevertheless, the latter materials can be used if desired with equal facility due to the ease of adjusting the apparatus.

In winding the fin on the tube, the metal in theouter edge portion of the fin or leg is subjected to a drawing action whereas the metal of the inner edge portion of the le and the foot is compressed. This ordinarily results in producing .a ripple either radially on the leg or longitudinally on the foot, with consequent poor me'-' chanical and thermal contact because any gaps between the periphery of the tube and the adjasurface of the tube.

cent inner surface of the foot thereby materially reduce heat transfer efficiency. This undesira ble result is prevented by providing means for pressing or ironing the foot smoothly against the Furthermore, after the fin is applied to the tube and the foot compressed against the periphery thereof, it has been found necessary to guide and to straighten the convolutions in order to avoid uneven spacing of the fin convolutions, as well as to insure the proper radial position of the leg on the tube.

For this purpose, means for guiding the fin after the foot has been compressed against the tube are provided in the form of a nut assembly having laminations which form a spiral groove in conformity with the desired pitch of the finished product. The invention also includes means for positioning the spiral guide brackets as well as of applying variable pressure to the ironing element. j

A primary object of the invention, therefore, is to produce a spirally finned tube which is entirely free of all ripples and splits in the leg and foot portions.

A further object of the invention, therefore, is

to providea head assembly for a finned tube Winding machine which eliminates all rippling in both the leg and the foot of the fin and at the drawn as it is applied to the periphery ofthe tubing, the sections of which may be independently adjusted to achieve proper application and contour of the fin.

A further object of the invention is to provide in a tool of the character described, a novel means for pressing or ironing the foot of the fin smoothly upon the surface of the tube.

A further object of the invention is to provide means for regulating and varying the angularity and pressure of the ironing means.

A further object of the invention is to provide a laminated guide nut. construction for winding fiat fin material onto a cylindrical element.

. A still further object of the invention is to provide a method of fabricating finned tubing. Further objects will be apparent from the specification and drawings in which: I

with the tool segments in place; 1

- Fig. 2 is a plan of the structure of Fig. 1;

assembled tool segments sectioned along the lines -5 of Fig. l and shown with each side in opposite perspective;

Fig. 6 is .a schematic sectional representation on the same plane as that of Fig. 5 but showing the tool segments in operative position with relation to a section of finned tubing as it is turned 7 through the segments;

Fig. 7 is a reduced sectional view s1 tool Fig. 10 is an enlarged detail of the ironer tip as it presses the foot around the tube;

Fig. 11 is an exploded view of the feed segment of the tool showing its laminated construction and lubricant passages; g Fig. 12 is a perspective view of the ironer or upper tool segment assembly; I j

Fig. 13 is an enlarged perspective'fview of one of the upper tool segment laminae;

Fig. 14 is an enlarged perspective view of .one of the lower tool segment laminae; T Fig.'15 is a sectional view'along the lines i5-i 5 of Fig.1;' i 'Q Fig. 16 is a schematic View illustrating'the first step in the method of applying the spiral fin to the tube; f I I Fig. 17 is a schematic view of the second step showing the first tool segment in closedposition;

Fig. 18 is a schematic view of the third'step showing the first and second tool, segments in closed position, and

Fig. 19 is a schematic view of the fourth step 7 showing all the tool segments in closed position.

The invention resides essentially in a tool comprising afixed guide for initially presentingthe preformed fin to the periphery of a rotating tube; a pivoted ironing or pressing means adaptedto press the foot of the fin smoothly against the periphery of the rotating tube; and a ,pair of pivoted jaws having internal spiral grooves adapted to receive the fin as it passes out of the ironer and to' straighten it during further rotation of the finned member. The guide, ele-' ment, ironing member and jaws are arranged about the tube and are movable into .int ercooperative association with each other, and with a fixed guide to form an internally threaded spiral tool.

The fixed guide is provided with suitable coolant passages for applying coolant to the fin at the point of maximum stress; namely the first convolution of the fin on thetube. The ironing member is made adjustable not only with re& spect to the other segments but also withrespect to'its carrier and the pressure which it applies to the foot. The invention also includes the principal steps in applying the fin to the tube.

Referring now more particularly to the drawings, the fin winding head assembly has a guide A displaceable segment 2 8 is idiustably retained in bracket 29 pivoted to plate 26 by means of cap screw 30. Lever arm 3| is secured to bracket 29 and serves to pivot the segment 28 from oper milar to Fig. 6 but with the tube shown only in phantom;-

Fig. 8 is a view similar to Fig. 7 but of the;

force between segment 28 and tubing 32. It will be understood that the apparatus described herein is capable of applying a fin to any generally cylindrical object and reference to tube or tubing is intended to include both hollow and solid members such as rods, bars, and sleeves.

Nut segment 33 is mounted in bracket 34 which islikewise pivotally secured to plate 26 by means of cap screw 35. Handle 36 attached to bracket 34 provides means for swinging the bracket and segment 33 into place against tube 32.

The lower nut segment 37 secured in bracket 331s likewise pivoted on cap screw and is operated by means of lever 38. A locking clamp on bracket 34 serves to securely retain segments 33 and 31 in operative closed position.

It will be understood that for purposes of clarity, only the fin applying structure is shown but that the entire machine includes mechanism for rotating and advancing tube 32 through plate 25. Also (not shown) are the strip feeding and forming rollers as'well as the carriage for receiving a finished finned element. These allied structure s while essential to the complete operation of the machine, form no part of the present invention and are well known in the art.

In general, ,a strip of fin material 4| having a vertical leg portion G2 and a horizontal foot portion it (Figfe), which is formed in passing through suitable dies or rollers (not shown), is fed through guide blocked (Fig. 11). The leg of the fin is'provided with a tapered or cut away portion of the leg at 155. When initially applied to the'tube, the tip of the'fin Mis secured to theperiphery of tube 32 by welding, (Fig. 16) whereupon brackets 29, 3 5 and 38 with their respective laminated segments are clamped about thetube iiz as shown in Fig. 1.7 The machine is then operated. to rotate tube 32 in clockwise direction asshown in'fFigs. 1-4 and at thesame quadrant'al face 46 of substantially the same closed fg uide fonthe fin material along with ative to inoperative position and vice versa, as.

well as to provide ameans for applying clamping at substantially its upper terminus.

radius as tube 32. ,A channel 41 (Fig. '7) adapted to receive the foot Q3 of the fin material, extends lengthwise of block 44 and tangent to face. 46 A groove t8, milled in one face of block .44 to a depth slightly greater than the thickness of leg 42 provides, in conjunction with channel 41, an L-shaped feed passageforthe'strip to the point of contact with the periphery of tube 32. The inner face of block M isrecessed at 49 immediately above the .terminus'of channel t! to provide means for application of lubricant orcoolant through hole 58 which connects with recess l5l inblock M. Passage Eilalso communicates with the face of slot 48 by means of hole 52 drilled at right angles to passage 50. ,v

Plate 53 of the same general configuration as block M is 'bolted to the side of block M3 by means of screws 2"! and'serves to form an engrooves. ii and} 48'.. Onefcorner of 7 plate 53 is concavely ground to formla face 54, coextensive with face Quin block 443 and is also provided with a tapering milled surface ,or flat 55 having somewhat greater radius than the outside of the completed finned tubing.v The degree of spiral taper applied to fiat 55 is such that it conforms to the desired pitch of the fin as it is being applied and likewise forms a part of one of the spiral grooves in the complete tool assembly. Plate 53 is also provided with suitable drilled holes 56 through which cap screws 21 extend and a slot 51 onthe plate accommodates projection 58 for lubricant manifold 59. Manifold 59 is provided with a nipple 60 internally threaded to accommodate, lubricant or coolant supply connection 6| (Figs. 1-3) and the manifold is bolted to block 44 through plate 53. Nipple 60 is drilled as is projection 58 to provide lubricant connection between the nipple and passage 50.

Referring now to Fig. 12 which is an enlarged perspective of adjustable segment 28, it will be seen that this section is constructed of a body member 1|] of rectangular shape, having a quadrantal concave face H at one corner and of a radius substantially the same as that of the tube 32. A larger quadrantal milled flat 10a on block 10 is cut at a bias with the face of the block in an amount corresponding with the pitch of the spiral fins. An arcuate pressing member on ironer 12 fits in the large flat '|0a and is rigidly secured therein. The lower edge 13 of member 12 is flush with the corresponding edge 14 of block 10, whereas the upper, extremity of member 12 extends beyond the lateral surface 15 to form a projecting nose 16. When member 28 is in operative position, nose 18 projects into the recess 49 in guide block 44 and serves to iron out any ripples which might otherwise have a tendency to form in the foot of the fin material before actual contact with the tubing. The method in which nose 18 cooperates with the foot even before contact with the periphery of the tubing is illustrated in Fig. 10.

Also, bolted to block 10 (Fig. 12) is guide plate 11 which is of the same general rectangular shape as block 10 except that the face 18 of plate 11 has a radius adapted to bear against the compressed foot of the fin after having been wound on the tube. Sufficient clearance at 19 between the side of face 18 and. ironer 12 is provided to permit free passage therebetween of leg 42 of the fin as the latter feeds therethrough. The offset guide surface of member 1'! partially underhangs the large milled fiat 18a in block 10 as shown at 80 in order to provide proper spiral pitch. Plate 11 is also notched at 8|, 8|, 8| to accommodate adjusting screws 82 (Fig. 3) which support member 28 in recess 29a of bracket 29.

The location of screws 82 in bracket 29 is such that assembly 28 is firmly retained in bracket 29 and is capable of adjustment in all directions in a radical plane by means of screws 82.

After being pressed upon the tube, the fin continues to be guided and formed by means of further travel through the tool segments. The torque necessary to draw the strip through guide block 25 and around the periphery of the tube has a tendency to cause the leg portion 42 to buckle, particularly at its base where it is compressed, and also to induce waves or ripples in the foot portion. The pressure exerted by member 12 operates to smooth and eliminate all ripples in'the foot 43, and the axial spacing of members 12 and 11 at 19, as well as the additional guide-members 85, 85a. serve to preclude formation of any ripples inthe leg portion 42.

;G uides, 85a maybe stamped or ground from steel plates as shown in Fig. 13 and have clamping surfaces 86, 86a and biased semicircular flats 81-, 81a. which likewise correspond to the pitch of the spiral. Fig. 5 shows the assembled relationship of guides or plates 85, 85a in nut segments 33 and 31. In the preferred embodiment four stacked plates 85a comprise of guide 85a in Fig. 14, from thence upwardly in front of face 81 in guide 85 of Fig. 13, and thence clockwise around the frontof face 81a and guide 85a.

In operation, the fin material is fed through guide block 25 and a triangular portion is cut from the leading upper edge of the strip as shown in Fig. 16. This enables the initial bending action to take place without maximumdeformation of the leg until approximately 'one convolution of the fin has been wrapped around the tube 32. The end of the'strip is then spot welded to the tube as shown in Fig. 16, whereupon bracket 34 is rotated into closed position by means of lever 36 as shown in Fig. 17

Bracket 29 is then rotated into position by means of 'lever 3| and may be securely locked by a rotatable cam 90 actuated by handle 9|, which also enables variable pressure to be applied to nut segment 28 through lever 3|. The total pressure applied with a tool segment depends of course, upon the angular position of handle 9| so that when the pipe section is in place, the pressure applied may be varied within limits by rotating the handle 9| to engage the surface of cam 90 progressively with lever 3|. A suitable limit stop 92 prevents the handle from obstructing the path of the lever 3| in closing. A pointer 93 on the cam 98 conveniently serves to indicate the most desirable position for handle 9| and may be used as a reference point to increase or decrease the pressure exerted. Guide 94 serves to retain lever 3| in position, thereby preventing misalignment due to twisting on pivot 30. Fig. 18 illustrates the nut segments 28 and 33 in place.

Bracket 38 is then closed as shown in Fig. 19,

so that the guide plates 85 cooperate radially with each other to forma complete internal spiral nut for guiding and shaping the fin.

V Brackets 34 and 38 are clamped in position by means of bolt 40 rotated with handle 95. This serves to engage lug 96 with shoulders 91 (Fig. 15) on block 98 which is in turn bolted to bracket 38 by means of cap screw 99 and washer I00. Proper locking action of brackets 34 and 38 may be retained at all times by means of adjusting block 98 with adjusting set screw |0|. After all the segments have been securely locked in position, the tubing is then rotated in a clockwise direction in Figs. 3' and 9, thus drawing the fin stripfonto the periphery of the tube as it is at the same time advanced longitudinally through plate 26 in accordance with the predetermined pitch. The mechanism for turning tube 32 and advancing it form no part of the invention. A bearing'sleeve ||l2 inplate 26 serves to guide the assigns advancing tubing i the proper position with respect to the nut segments;- Y

Figs. 8-clearly show the assembled relation of the various segments and the manner m w-hich the spiral groove between "the laminated segments serves to straighten the legs of the spiral fin-after its initial application to tube 32." Fig.5 is a true perspective clearly showing the individual laminae formed by means of the plates 85.

It will be "noted that the "fin forming face=8'l'of segment "33 in Fig. '8 underhangs the adjacent shoulder on segment "2i8at l 05, and it is this construction which requires that bracket 34 be pivoted into operative position as shown in Fig.

'17, "beforebracket 29 is swung intoplace. The

lever 3| is ample to provide sufficient compressiv force forlthis purpose."

Furthermore, the adjustability of the nut segment 28 with respect to the-bracket 29 enables the operator to control to a high degree the results obtained.

I have therefore provided a winding head for finned tubing machines which produces a greatly improved product in that much higher heat transfer is obtained by means of the relatively wide leg of the fin, plus the tight contact'between the foot and the surface of the tube. The apparatus is'designed for mass production of finned tubular elements and is extremely simple to operate.

'I claim:

1. A sectional tool'assembly forapplyingtoa cylindrical member a spiral fin having a radial ment, a quadrantal'cylindrical frontfaceionthe adjustable section adapted'to press the foot of the spiral 'fin'a'gainst the cylindrical' memberduring the first'lfln -convolution, a'second guide plate in spaced axial relation with the adjustable'section and secured thereto, said secondguide'plate having anaxially facing flat biased in accordance with the pitch of the fin, and means" for clamping said? bracket and adjustable nut segment against'the foot of'thejfin,

2. A sectional tool assembly in accordance with claim] 1, ha'ving'a pair of pivoted nut segments adapted to beclamped around 'the'cylindrical member andfhaving internal spiral grooves adapted to receive the fin vconvolutions as the tubing'is advancedthrough 'theiffixed'guidefblock andithe adjustable nut segment 1 3.. A sectiojnal tool assembly accordance with claim 1 "which the adjustable nut; segment carries an iro'ner having a helical 'quadrantal face inprogressive helical'relationto the quadrantal 8. face'on the adjustablesegment and anose'on the ironer extending-into the fixed guide'block;

4. In apparatus for applying spiral finhaving a radial legand an axial foot to acylindrical member, a" sectional tool assembly having an upper pivoted nutsegment comprising'a plurality of laminationseach lamination having a concave semicircular and radially biased fiat, said flats being axially spaced with respect to each other, a pivoted lower nut segment comprising a pinrality of laminations; each lamination having a concave semicircular and radially. biased flat, said flats being axially spacedwith respect to each other, the gaps between the flats forming a continuous internal spiral when-thesegments are closed, and means for clamping the upperse ment and the lower segmentaroundthe. circum ference'of the cylindrical member. s -5'. Inapparatus forcapplying a spiral fin havinga radial leg'and'anaxial foot to-a cylindrical member, a sectional nut segment comprising a body member havinganoutwardlydisposed concave cylindrical quadrantal front face at one corner, a'flat on the side of the body member, said flat being concentric with the front face and biased Withrespect to the plane of'the, body member, an ironing concave quadrantal pressure face concentric to the front facev of the body member and being substantially the width of the axial foot onthe fin, a nose on said ironing face and forming a "continuation thereof, said nose extending forwardly of the edge of the body memben'and a guide plate secured to the side; of the body member, said guide-plate having a helically disposed biased flat in spaced relation to the body member, the quadrantal ironing face being positioned in close proximity to the periphery of the cylindrical member whereby radial pressure'is applied to the periphery of the cylindrical'member by said face through thefoot-of the spiral fin;

6. Apparatus in accordance with claim '5,-hav-' ing a pivotally mounted bracket recessed to'posi in a radialrplane, and pressureapplyingmeans for forcing "the body .member and ironing face into contact with the cylindrical memberandfin through the bracket,

.8. A sectionaltool for applying toacylindricalf member a spiral 'fin having a radial leg and an axially extending'foot arranged circumferentially of the cylindrical member comprising, a fixed guide blocklhaving 'a slot'for feeding finned material substantially tangent to the periphery of saidicylindrical member, a 'guideplate attached to said block andhaving a helical quadrantal side'flat adapted to form a predetermined spiral pitch inthe fin, an adjustable nut segment in alignment-with the guide block,"a pivoted bracket for supportingthe adjustable nut segment, a quadrantal cylindrical front/face on the adjust ablesegment a'daptedt'o' press the foot of the spiral 'fin against the cylindrical member during the first fin convolution, a second guide plate in spaced axial relation to thefront face on the adjustable segment and secured-thereto, said second guide plate'having'a biased axially fac drical member; a second cylindrical quadrantal front face on the nut segment in progressive helical relation thereto; a nose on said second face extending beyond the edge of the body portion and positioned to receive the foot of the fin and to iron the foot against the periphery of the cylindrical member; and a guide plate secured to th side of the body portion, said guide plate mounted on a pivoted bracket comprising a plurality of laminations, each lamination having a concave biased semi-circular fiat axially spaced with respect to each other, the gaps between the flats of the second and third segments forming a continuous internal spiral when the brackets are pivoted to close the segments, and clamping means between the second and third nut segments to securely position the segments around the cylindrical member.

9. In apparatus for applying a spiral fin having a radial leg and an axial foot to a cylindrical member, a main support plate having a bearing adapted to guide the cylindrical member as it is rotatably advanced through the plate; a guide member for feeding the fin material to the periphery of the cylindrical member, said guide member being secured to the plate in spaced relation to the bore of the bearing and having a fin carrying groove extending at right angles to the bore of the bearing; a closure for said groove, said closure having a helical quadrantal facej a nut segment pivotally supported on said main support plate and adapted to be clamped around the periphery of the cylindrical member to cooperate with the guide member, said nut segment comprising a body portion having a concave cylindrical "quadrantal front face adapted to be pressed against the cylinhaving an axially biased fiat in spaced relation to the body portion to receive the leg of the strip as it is wound on the cylindrical member.

ALMA J. HARRISON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 917,401 Barnholt Apr. 6, 1909 1,032,925 Miller July 16, 1912 1,151,721 Sahlin Aug. 31, 1915 1,243,179 James Oct. 16, 1917 1,404,122 Hofwing Jan. 17, 1922 1,492,067 Brinkman Apr. 29, 1924 1,630,912 Whittingham May 31, 1927 1,905,762 Stone Apr. 25, 1933 1,924,946 Kott Aug. 29, 1933 1,981,566 Nigro Nov. 20, 1934 2,145,244 Berg Jan. 31, 1939 2,383,253 Ingalls Aug. 21, 1945 2,416,865 Blonander Mar. 4, 1947 2,472,245 Busse June 7, 1949 FOREIGN PATENTS Number Country Date 411,316 Ger-many Mar. 30, 1925

Images