US2532239A - Finned tube winding machine - Google Patents

Description

NOV. 28, 1950 J, s, NEWL|N 2,532,239

FINNED TUBE WINDING MACHINE Filed July 25, 1948 5 Sheets-Sheet 1 lhipley Neu/Zin 25g hl2somffys #ZW/:6MM

Nov. 28, 1950 J. s. NEwLlN `2,532,239

FINNED TUBE WINDING MACHINE Filed July 23, 1948 5 Sheets-Sheet 2 I 'ful-[ Inverzor JJM/Weg Newl'z'n/ 5y his Homeys Nov. 28, 1950 J. s; Nr-:wLlN 2.532,239

FINNED TUBE WINDING I ACHINE Filed July 23, 1948 5 Sheets-Sheet 3 Nov. 28, 1950 J. s. Nr-:wLlN

FINNED Tum: WINDING uAcHINE 5 Sheets-Sheet 4 Filed July 25, 1948 @i f fl||| 1| i ma y m l im, /1 O w 521m L 4 T MWMLLM m G. a -wkv m Wn YRS,

5 Sheets-$hnt 5 fwenof lShipley Newlin by M5 omey bbw/76M J S NEWLIN FINNED TUBE WINDING IIACHINE Nov. 28,1950

F'lled July 23, 1948 Patented Nov. 1950 2,532,239 man TUBE WINDTNG MACHINE John Shipley Newlin, Paoli, Pa., assignor to Merchant Evans Company, Philadelphia, Pa., a corporation of Pennsylvania Application July 23, 1948, Serial No. 40,389

3 Claims.

This invention relates to `a machine for fabricating finned tubing of the type commonly used for heatA exchangers. The invention includes an improved ilnned tube construction as well as the machine for fabricating same.

Although the prior art contains many forms of ilnned tubing in which a length of tubing is helically wound with a strip of heat-radiating material. many of these devices have contained inherent objections. In the rst place, the conventional winding machine is complicated and expensive; the rate at which the machine could wind tubing has been relatively slow; the heat transfer, which in turn depends upon the surface o! the fin, has been inefficient; and the product has been unable to withstand hard usage.

A primary object therefore of the invention, is to provide a simple, inexpensive winding machine for finned tubing which is extremely easy to operate and adjust.

Another object of the invention is to provide an article of manufacture characterized by a fluted n, the fin being smooth around its outer periphery and having feet-at the base of the formed leg pressing the flutes into tight overlapping relationship to extend from either side of the fin, thereby providing maximum heat transfer surface, extreme fin rigidity, and excellent conductivity between the tube and the fin.

Further objects will be apparent from the speccation and drawings in which:

Fig. 1 is a plan of the entire n winding machine;

Fig. 2 is an enlarged front elevation of the Winding head;

Fig. 3 is an enlarged longitudinal sectional view as seen at 3--3 of Figs. 1 and 2;

Fig. -i is an enlarged sectional detail showing the pressure rolls and a portion of the winding head;

Fig. 5 is a sectional detail as seen at 5--5 of Fig. 4;

Fig. 6 is a sectional Fig. 5;

Fig. 7 is an enlarged sectional detail of the crimping rolls as seen at 1--1 of Fig. 3;

Fig. 8 is an enlarged sectional detail as seen at 8--8 of Fig. 1;

Fig. 9 is an enlarged sectional detail of the belt-drive as seen at 9-9 of Fig. 1;

Fig. 10 is a perspective of a lengthof 'finned tubing as wound on the machine;

Fig. 11 is a longitudinal section of the finished product of Fig. 10;

detail as seen at E-B of it is being wound on the tubing; and

Fig. 13 is a section as seen along the line 13-13 of Fig. 12.

The winding machine is of the rotating head type having a central sleeve which acts as a guide for the tubing and also journals the gears for driving one of the pressure rolls. The tubing is fed axially through the sleeve by means of a series of feed rolls geared to the sleeve. The feed rolls not only control the rate at which the tubing is fed through the sleeve, but also serve to form a series of axial flats or grooves in the tubing, the function of which is of importance in the finished product. A supply of strip material is carried on the winding head by means of an annular support mounted on rollers, and is fed through a pair of crimping wheels also on the head. A beveled pressure roll or disc is mounted on the head and ls adapted to cooperate with a backing pressure roll also journaled on the head bui; independently driven. The first roll is axially adjustable and driven only by friction. Both of the rollers may be tangentially adjusted in the head with respect to the periphery of the tube. For purposes of clarity, the floating pressure roll will be referred to as the pressure disc and the driven roll as the backing roll; nevertheless it will be understood that both rolls exert pressure adjacent each other through the iin.

The axis of the pressure disc is set at the angle of about 20 to the axis of the tube; whereas the axis of the backing roll is perpendicular but slightly oiset to the axis of the tube. The disc and pressure rolls may be adjusted with respect to each other and they are both mounted in a bracket which is adjustable with respect to the head. This range of adjustability enables any desired eiect to be produced in the iin .and also permits the machine to wind iins of different materials. l

The drive for the winding machine is from an electric motor through a pair of V-belts, and the engaging device permits gradual starting to avoid rupture of the strip. The winding head is driven through back gears from the main shaft and the feed rolls are also driven from the main shaft through a pair of sprockets and suitable bevel gears.

The machine is especially designed to apply a relatively soft, ductile material such as copper or copper alloy, although other materials may be employed equally well by making suitable adiust ments. The crimpers form a wavy edge on the strip, the Waves being of relatively low amplitude. The outer edge of the strip is securely gripped between the pressure disc and the backing roll and wiped around theperiphery ofthe tubing as it advances through the head. This wiping action not only attens the waves radially against each other but also serves to bend the base of the waves around the periphery of the tubing to form a thickened foot portion for the iin on either side of the fin. The axial flats in the tubing formed by the feed rollers act as keys to prevent unwinding of the iin and it has been found unnecessary to attach the fin to the tubing in any way other than the pressure produced by the winding head.

Referring now more particularly to the drawings, the winding machine is supported on a bench or table 26 by means of upright brackets 2l, 22,

23 and 24. Brackets 23 and 24 support the feed roll assembly, whereas brackets 2l and 22 journal the winding head and driving mechanism. A hollow shaft or spindle 25 is journaled .in annular ball bearings 26 and 21, mounted in posts 2l and 22 respectively (Fig. 3). A driven pulley 23 is keyed to spindle 25 and positioned thereon between posts 2l and 22. Lock nut 29 retains pulley 28 on spindle 25. One end of the spindle carries a spur gear 36 and a small sprocket 3l, both of which are retained on the spindle by means of lock nut 32. The opposite end of spindle 25 carries integrally therewith the winding head assembly 33 which comprises a plate 33a mounted on the enlarged hub portion 25a of spindle 25. A hub member 34 is independently journaed on spindle 25 between head 33 and post 2 l. This hub is free to rotate on the spindle but is axially retained thereon by means of flange 35 and lock nut 36. Hub 34 carries a spur gear 31, and a bevel gear 38 which engages bevel gear 35 on the backing roll shaft 46 so that the drive for backing roll 4l can be varied independently of spindle 25 through back gears 42 and 43 (Fig. 1) mounted on countershaft 44 which is in turn journaled in posts 2l and 22. Gear 43 meshes with gear 36 on the spindle so that the revolutions of hub 34 and shaft 46 are controlled by the ratios of gears 36, 43 and 31, 42.

The tubing 56 moves axially and non-rotatably through the bore of spindle 25 in controlled relation to the rotational speed of winding head 33 and backing roll 4|. A series of pressurized feed rolls 5I in alignment with the bore of spindle 25 are mounted on longitudinally extending brackets 52, 52 supported on posts 23 and 24. The feed roll assembly in the preferred form comprises three sets of rolls, each set having an upper grooved roll 5Ia and a lower complementary feed roll 5Ib. The lower rolls 51h are resiliently suspended from brackets 52 by means of studs 53 loosely tting in brackets 52 and supported on the top of brackets 52 by helical springs 54 and lock nuts 55. Suitable adjustment of nuts 55 enables the desired pressure to be provided on the tubing as it passes between the rolls. In practice however, it has been found that the movement of the upper and lower rolls with respect to each other is extremely limited for any given size of tubing, so that each lower roll 5Ib may be driven by means of spur gears 56 and 51 mounted respectively on upper roll shafts58, 58a, 58h, and lower roll shafts 59, 59a, 59h (Fig. 3). The shape of the rolls themselves is such that the contact area with the tubing is limited to four diametrically opposite areas on the rolls, so that four continuous axial flats or grooves on the tubing are formed as it feeds through the rolls. The middle roll shaft 58 is extended to carry a bevel gear 66 and a pair of sprockets 6I and 62. Roll shafts 58a and 58h are driven by chains 63, 63 connecting driven sprockets 64. 64 on roll shafts 4 58a, 58h and sprockets 6I, 62 on shaft 58. Be gear 66 is driven in timed relation with spindle 25 through pinion gear 65 journaled in posts 66 and carrying at its opposite end a sprocket 61 connected to spindle sprocket 3| by means of chain 6B. It will thus be apparent that various lengths of tubing 56 are fed into the first pair o! feed rolls whereupon the tube is axially moved through the succeeding pairs of rolls into the bore of spindle 25 until the tube projects through the winding head 33.

Driving means both for the spindle and the feed rolls is from an electric motor 16 slidably mounted on plate 1I and having a pulley 12 in alignment with pulley 28, both pulleys carrying belts 13, 13. Since it is important that the winding head and spindle be brought up to speed slowly, motor 16 is slidably mounted on plate 1I by means of slots 14, 14. A lever 15 pivoted to plate 1i and having a spring loaded pawl 16 serves to move motor 16 in slots 14, thereby loosening and tightening belts 13. The advantage of this construction lies in the fact that the motor switch may be closed Without starting the winding head or spindle when motor 16 is in the loosened position as shown in broken lines in Figs. l and 9. In this position, belts 13, 13 are held completely out of contact with pulley 12 by means of spaced arms 11, 11 horizontally mounted on bracket 18. As lever 15 is moved upwardly in Fig. 1, pulley 12 gradually engages belt 13 to start the winding machine smoothly. When the winding head and feed ro-ls have been brought up to speed so that no slippage occurs in the belts, motor 16 is locked in a tightened position by means of pawl and ratchet 16. It will be understood that the slipping belt mechanism is merely illustrative of any device for gradually bringing the winding head up to speed. Other well known means of accomplishing this effect may be incorporated, such as a slipping clutch or a fluid coupling.

Referring now to Figs. 2-7, the winding head assembly is adapted to receive a coil of flat ductile strip material 86 which is stored on an annular carrier 8l rotatably mounted on head plate 33a by means of rollers 82 supported on the head by cap screws 83 and adapted to lit in an internal groove 84 in the carrier 8l. The coil of strip material 86 isvretained axially on carrier 8l by means of a retaining cover plate 85 having ini spection holes 86, 86 and secured to head plate 33a by means of thumb nuts 81, 81. A flanged pulley 88 is mounted near the periphery of plate 33a, the axis of the pulley being mounted at approximately 45 to the plate so that the strip feeds from the supply coil through a fixed guide 89 over pulley 88 and into a second fixed guide 96 which changes the position of strip 86 so that instead of the flat portion of the strip being parallel to the axis of the machine, it is now at right angles thereto. From guide 96, the strip feeds between a pair of crimpers 9 I 9| which are keyed to shafts 92, 92 mounted in bearings 93, 93 and lbrackets 94, 94 on plate 33a (Fig. 7). The opposite ends of shafts 92 carry a pair of spur gears 95, 95 so that the teeth of the crimpers are constantly in meshed relation. Guide 96 feeds the strip 86 through the crimpers so that from 1/2 to 3A of the surface of the strip is crimped as shown clearly in Figs. 2 and 7. From the crimpers the strip passes through abifurcated guide block 95, the forks of which are spaced sufficiently far apart to accommodate the partially formed crimps 61 in strip 86. Guide block 86 terminates assenso nearthe peripheryoftubell atapointinradial alignment with theedge ofbacking roll 4I.

'I'he pressure disc III is keyed to shaft III and journaled in annular ball'bearings |02. |02 which in turn are supported in a housing |03.

The shape of pressure disc IIIII is of especial importance in forming the desired properties of the iin. Referring to Figs. 3 and 4. it will be seen that the disc is mounted in bracket Ill at an angle to the horinontal centerline of the tubing. The cross section of the disc is of generally frusta-conical shape but the conical surface is of dual nature in that a substantially long portion Illa ispositioned at right angles to the center of the tube and is adapted to be maintained in spaced relation to the serrated upper portion 4 Ia of backing roll 4I. '111e peripheral surface of disc is beveled at a slightly increased angle to provide relief and a forming surfacefor the crimps and this surface is adapted to register with a similarly beveled periphery lib of backing roll 4I (Fig. 4) The opposite peripheral edge of disc in is provided with an annular recess Ilc to provide clearance for the formed ilns and to enable the pressure disc to be positioned between the fins as they are formed. Suitable axial adjustment for pressure disc |00 is provided by means of adjusting screw III which acts through thrust bearing il! at housing Ill. Adjustment of the housing I Ill may be made by loosening cap screws |06 which mount the bracket on plate 33a.

The backing roll (I has a serrated vertical face l Ia and a tapered face I Ib which cooperate with the conical edges of disc IIII as described above. It has been found that the location of the center line of shaft Il with respect to the center of the tube is of extreme importance in the proper ap plication of the iin. A lead of approximately 5%" has been found to give desirable results with soft copper strip material. Fig. 6 illustrates this lead and shows the center line of shaft Il displaced horizontally in the direction from which the iin is being wound on to the tube.

The axial position of shaft IIiI and pressure disc llt may likewise be adjusted with respect to the axis of shaft 4I in order to vary the gap between the disc and the pressure roll as seen in Fig. 5. However, it will be understood that in some cases it may be desired to offset the axis of the shaft 4I! and disc Ill while retaining substantially the same gap between the roll and the disc. bracket |03 as well as the lateral adjustment of the entire bracket and disc in a line at right angles to a radius of the winding head 33, is an important element in obtaining improved adhesion and forming of the n. When shaft 40 is positioned The above axial adjustment of the disc in 4 as shown in Fig. 6 to provide a lead, the partially formed crimps 91 will be wiped onto the periphery of the tube and preed radially inward to provide the tangential feet shown clearly in Figs. l1-13. If the shaft Il is moved to the left in Fig. 6, this wiping action may be eliminated so that the crimps Sl will be radially unbent. In this event, of course. it may be desirable to utilize some bonding material such as solder or brass for the iin and the tube. A semicircular collar I |11 (Fia. 4l is mounted in the bore of spindle 25a by means of cap screws |08. in order to provide suitable guiding and backing for the tube at the point opposite to the application of the fin.

The fin, when applied in accordance with the mechanism heretofore described. is characterized by a corrugated radially tapering web shown s clearly in Figs. lit-13. In effect, the fin is wipd on to the periphery of the tube and the hase of the iin is folded and pressed to form a foot. as shown in Fig. 1l. 'I'he webs do not extend along a diameter of the tube but vary fromv an inner tangential position at the periphery of the tube to a somewhat radial position at the point where the webs blend into the smooth periphery of the iin. In operation, the cylindrical member or tube il is fed axially through spindle 2l and collar lill by means of the power-driven rolls II, lia from right to left (as seen in Fig. 3). Spindle Il is rotated ata predetermined speed by motor 'Il through belt 'Il and pulleys 2l and 12. Spindle 2l drives the back gears Il and I2 by means of spur gear ll (as shown in Rig. l) and the winding head which is journaled on spindle 2l isin turn rotated at a differential speed with respect to spindle 2B by means of bevel gears I8 and 3l.

This action not only causes the backing roll 4I to rotate on its own axis but also to revolve as a unit with a head around the cylindrical member SII. The hat strip material 8l which is fed through the crimpers 8l, DI is tightly engaged between the pressure Ill and the periphery of backing roll II so that as the winding head. together with the pressure disc `Ill and roll 4I, revolve around the periphery of cylindrical member 50. the crimped iin material iswiped around the periphery of the cylindrical member under substantial tension. i

The action of the disc and backing roll is such that the inner edge of the strip is foldably compressed around the periphery of the tube and at the same time the outer edge of the strip is and this concentration of iin material around the erties ofthe iin are likewise enhanced. The conl centration of fin material and relatively greater contact area at the base ofthe n enable greater conductivity of heat from the tube to the iin. As the heat progresses radially outward. the material in the iin decreases, whereas the surface area increases and it has been found that a remarkably eiilcient heat'I transfer is thereby obtained.

I claim:

l. In apparatus for winding strip material around the periphery of a cylindrical member, a hollow sleeve through which the cylindrical member is axially fed. a support in which said sleeve is journaled, a plate mounted at one end of said sleeve. an annular carrier journaled on said plate for rotatably positioning a supply of strip material. a pressure disc mounted onsaid plate and adapted to rotate independently thereof, a shaft for said pressure disc. the axis of said shaft being biased with respect to the axis of the hollow sleeve. means for axially adjusting said pressure disc shaft. a backing roll journaled on said plate.

the axis of said backing roll being substantially perpendicular to the axis of the cylindrical mem- ,Y

ber, means for adjusting the position of the backing roll with respect to the periphery of the cylindrical member, means for rotating the hollow sleeve, and back gears for independently rotating the backing roll. l

2. Apparatus for Winding nnedtubing comprising a supporting member, a hollow sleeve horizontally journaled in said supporting member, a hub journaled near one end of said hollow sleeve, a bracket adjustably mounted on said hub, a backing roll shaft journaled in said bracket, a backing roll mounted on said shaft and adapted to rotate in a plane parallel to the axis of the hollow sleeve, a bevel gear mounted at the opposite end of said shaft, a bevel gear mounted on said hub and adapted to mesh with said iirstnamed bevel gear, a gear train connecting the bevel gear on the hub with the hollow sleeve, and means for rotating the hollow sleeve in its jour nals.

3. In apparatus for winding strip material around the periphery of a cylindrical member, a hollow sleeve through which the cylindrical member is axially fed, means for feeding said cylindrical member through the hollow sleeve, a support in which said sleeve is journaled, a plate mounted at one end of said sleeve, an annular carrier journaled on said plate for rotatably positioning a supply of strip material, a bracket on said plate, a pressure disc journaled in said bracket and adapted to rotate independently thereof, a shaft for said pressure disc, the axis of said shaft being biased with respect to the axis 'of the hollow sleeve, means for axiallyadjusting said pressure disc shaft, a backing roll journaled 8 on said bracket, the axis of said backing roll being substantially perpendicular to the axis of the cylindrical member, means for adjusting the bracket in a line substantially perpendicular to a radius of the plate whereby the pressure disc and the backing roll are moved simultaneously with respect to the periphery of the cylindrical member, means for rotating the hollow sleeve, and back gears for independently rotating the backing roll.

J. SHIPLEY NEWLIN.

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

UNITED STATES PATENTS Number Name Date 1,151,721 Sahlin Aug. 31, 1915 1,472,719 Horvath Oct. 30, 1923 1,629,918 Kastler May 24, 1927 1,840,317 Horvath Jan. 12, 1932 1,868,438 Thomas July 19, 1932 1,950,623 Owston Mar. 13, 1934 1,972,230 Lehman Sept. 4, 1934 1,992,297` Dewald Feb. 26, 1935 1,997,197 Nigro Apr. 9, 1935 2,002,793 Park May 28, 1935 2,082,600 Squires June 1, 1937 2,087,723 McCord July 20, 1937 2,089,381 Kassing s Aug. 10, 1937 2,152,437 Lear Mar. 28, 1939 2,273,157 Tenney Feb. 17, 1942 FOREIGN PATENTS Number Country Date 29,458 France May 5, 1925

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