US2865424A

US2865424A - Machine for forming finned heat transfer tubes

Info

Publication number: US2865424A
Application number: US484391A
Authority: US
Inventors: Arthur H Mcelroy
Original assignee: COYNCO PRODUCTS Inc
Current assignee: COYNCO PRODUCTS Inc
Priority date: 1955-01-27
Filing date: 1955-01-27
Publication date: 1958-12-23
Anticipated expiration: 1975-12-23

Description

Dec. 23, 1958 A, H. MQELROY 2,865,424

MACHINE FOR FORMING F INNED HEAT TRANSFER TUBES Filed Jan. 27, 1955 7 Sheets-Shasta 1 Dec. 23, 1958 A. H. MQELROY MACH INE FOR FORMING FINNED HEAT TRANSFER TUBES '7 Sheets-Sheet 2 Filed Jan. 27. 1955 Dec. 23, 1958 A. H. McELRoY 2,865,424

MACHINE FOR FORMING FINNED HEAT TRANSFER mass Filed Jan. 27, 1955 7 Sheecs--Sheet 3 Dec. 23, 1958 A. H. M ELROY I 2,865,424

MACHINE FOR FORMING FINNED HEAT TRANSFER IUBES Filed Jan. 27, 1955 7 sheets-sheet '4 Dec. 23, 1958 A. H. McELROY 2,865,424

MACHINE FOR FORMING FINNED HEAT TRANSFER TUBES 7 Sheets-Sheet 5 Filed Jan. 27. 1955 Dec. 23, 1958 A. H. MCELROY MACHINE FOR FORMING FINNED HEAT TRANSFER TUBES 7 Sheets-Sheet 6 Filed Jan. 27, 1955 Dec. 23, 1958 A. H. McELRoY MACHINE FOR FORMING FINNED HEAT TRANSFER TUBES 7 Sheets-Sheet 7 Filed Jan. 27. 1955 MACHINE FOR FORMING FINNED HEAT TRANSFER TUBES Arthur H. McElroy, Tulsa, Okla., assignor to Coyuco Products, Inc., Tulsa, Okla., a corporation of Oklahoma Application January 27, 1955, Serial No. 484,391 11 Claims. (Cl. 15.3-64.5)

This invention appertains to improvements in machines for forming finned heat transfer tubes and particularly relates to an improved machine for wrapping a strip of material spirally on a tube to form individual spiral fins on the exterior of the tube.

A primary object of this invention is to provide coopcrating means for simultaneously moving a tube axially While rotating it about its axis; the rotation of the tube effecting the wrapping of the fin strip stock on the tube, and for deforming the strip, as it is coiled on edge about the tube, to ensure the creation of a smooth spiral fin which has its inner peripheral edge in proper heat transfer association with the exterior surface of the tube.

Another object of this invention is to provide means for rotating a tube while moving it longitudinally, as the strip is wrapped on edge concentrically about the exterior thereof, and to provide means driven in an exact synchronous speed with the tube for deforming the strip as it is being wound on the tube, the strip being deformed in an exact ratio of the finned tube external diameter to the external diameter of the tube itself.

A further object of this invention is to provide guidemeans over which the strip passes, as it leaves a holder, the guide means being formed and mounted to hold the strip taut and protect the strip against accidental deformation due to shock.

A still further object of this invention is to provide a drive means for rotating and longitudinally moving a tube, which drive means is adjustable to accommodate tubes of various diameters and to advance the tu'oe longitudinally at ranging speeds, the latter function being important in providing control of the pitch of the fins wound on the tube from the strip.

A still further object of this invention is to form a smooth fin with a very low corrugated base or inner peripheral edge and, in this respect, to provide means for partially corrugating the strip while maintaining the rest of the strip free from strain and in a smooth condition, the corrugated portion forming the base or inner peripheral edges of the fins or tube side edge of the strip.

A further important object of this invention is to pro vide a novel means for rolling or extruding the smooth portion of the strip up to the corrugated portion, that is, the outer peripheral edges of the fins, as they are Wound on the tube, such means embodying cooperating forming rolls between which such portion of the strip passes. The forming rolls are rotatable about parallel axes perpendicular to the path of movement of the tube and receive the strip therebetween as it is starting to wind on the tube.

A still further important object of this invention is to 2,865,424 Patented Dec. 23, l 958 provide means for relatively adjusting the rolls bodily towards and away from each other so as to adjust the pressure of the rolls on the strip and to provide means for relatively adjusting the rolls about an axis transverse to the axes of rotation of the rolls to change the angle of attack thereof on the strip. 7 Another important object of this invention is to provide fin guiding means through which the tube transversely passes in its axial movement, the guiding means being formed and correlated with the forming rolls so as to lead the strip, after it leaves the rolls, around the tube,

while maintaining the fin in its formed position and under the stress imparted by the rolls.

A further important object of this invention resides in the provision of a rotatable support at the delivery or outlet end of the machine, which support guides and supports the finned portion of the tube to eliminate wear on the fins.

Generally considered, this invention contemplates the provision of an automatic machine wherein a tube to be finned is moved axially while being rotated about its axis and, after one end of the strip is fixed on edge to the exterior thereof, the strip is wound by the tube spirally on its outer surface. The strip is drawn from a rotatable holder over a resiliently mounted guide, which serves as a shock absorber and then through partial corrugating in a rotating barrel which rotates at approximately the same speed as the tube and prevents the imposition of ear on the finned surface of the tube.

These and ancillary objects, including the provision of a compact, automatic and easily operated-and controlled machine, are attained by this invention, the preferred embodiment of which is set forth in the following description and illustrated in the accompanying drawings, wherein: a a

Figure 1 is a perspective View of the machine, with the tube. shown moving from left to right as it is finned;

Figure 1A is a cross-sectional view taken on line 1A-- 1A and illustrating the means for supplying additional tubes to the machine, the tubes being axially aligned and secured in end to end relationship to form a large tubing;

Figure 2 is a perspective view of the drive means for axially feeding the tubes through the machine, while rotating the tubes;

Figure 3 is a diagrammatic illustration of the action of the feed wheels which comprise the drive means for the tubes;

Figure 4 is an enlarged perspective view of the forming head unit and guide means from the inlet end thereof;

Figure 5 is an end elevational view of the forming head unit from the inlet end thereof;

Figure 6 is an enlarged perspective view of the corrugating means which corrugates one longitudinal edge of the strip as it passes to the forming head unit, a guide element of which is shown in Figure 5;

Figure 7 is a diagrammatic illustration of the corrugat .ing wheels, showing that the corrugations are formed accuratelyfrom the plane of the strip while theother portion of the strip is maintained planar;

Figure 8 is an enlarged perspective view of the forming head rolls and guide means showing such guide means in operation as the fin is wrapped on the tube immediately after passage from the finning head rolls;

Figure 9 is an enlarged perspective view of the fin guide showing the spiral lead of the guide face thereof;

Figure 10 is an enlarged perspective view of the fin following guide;

Figure 11 is'an enlarged fragmentarytop plan view of the forming head unit and guide means;

1 Figure 12 is an enlarged longitudinal vertical sectional view taken on line 12-12 of Figure 11;

Figure .13 is an enlarged top plan view of the forming head rolls; and

Figure 14 is an enlarged longitudinal vertical sectional view taken on line 14-14 of Figure 13.

. .Referring now more particularly to theaccompanying drawings and initially to Figure 1, the machine 10 in- .oludes a feeding'section 12, a working section 14-and a .delivery or outlet conveying section 16.

The feeding section 12 includes a stationary supporting trough 18 which is horizontally supported by legs 20 and is disposed axially at one end of the working section 14. Alongside the trough and inclined upwardly therefrom, a table 22 is provided and is mounted on the legs.

The table supports a supply of tubes in side by side -fashion and means is provided for ejecting the tubes in single fashion from the table and carrying the selected tube onto the trough. As shown in Figures 1 and 1A,

a rod'24- is rotatably journalled in the upper ends of the legs and has a laterally offset handle 26,- which, when manually pulled, rotates the rod. Substantially triangular plates 28 are fixed at their apices on the rod and have rounded bases which are provided to cam over the tubes and hold them back, as the first tube is picked up thereby for deposit in the trough. To effect the pick-up of the 1 tubes, the sides 30 of the plates are notched, as at 32,

adjacent the bases and the wall of the notch is configuredin the form of a hook that will accommodate a tube. Thus, when the plates are in the position, shown in full lines in Figure 1A, the first tube will gravitate down and nest in the hooks.

When the rod is rotated clockwise, the plates will swing curvilinearly and pass through the slots 34 in the adjacent sdie wall of the trough to permit the tube to roll off the sides 30 onto the base of the trough and against the opposite side wall of the trough. In such position in the trough, the tube will be in axial alignment with the preceding'tube 36, whose rear end has cleared the last slot 34 in the wall (Figure l) and which is being processed 'through'the working section of the machine.

The working section 14 includes a horizontal'table top 38 which is supported by legs 40 and beneath which a horizontal frame 42 is provided. A plate 44 upstands from the top 38 and is positioned transversely thereon with a lateral mounting flange 46 on its lower end bolted "onto the top. The plate 44 has a large opening 48 to j-receive the tube 36, the opening being large enough in "diameter for the passage through the plate of tubes of varying diameters. A drive means for moving the tube .36, for example, axially over the top 38, while rotating 'it about its axis, is provided and is shown more particularly in Figures 2 and 3. As shown in such figures, the drive means includes three knurled

drive wheels

50, 52 and 54, which are grouped in a circular arrangement, 120 apart, around the opening 43. Each wheel is keyed "on a shaft 56, which is rotatably journalled in the legs 58 of a U-shaped carrier 60 for the wheels. An internally -.threaded sleeve 62 projects axially from the web 64.of veach carrier and the threaded shank of a bolt .66 is threaded in the sleeve. The bolts extend through aper- .tures inthe. lateral lugs 68 which are formed on the inner bolt'and hold the bolts in axially adjustedpositionsdn the lugs. By this mounting construction of the carriers 60, the wheels are adjustable radially of the opening 48 to drive tubes of varying diameters.

Means is provided to adjust the pitch of the Wheels in relation to the tube, which adjustment controls the speed of the longitudinal or axial movement of the tube and, therefore, the pitch of the fins as the strip is wrapped around the tube. Such adjustment means includes a saddle block 72 in which each sleeve is slidable and which is mounted on the face of the plate 44. A clamping plate 74 is releasably bolted over the sleeves to the blocks 72 and holds the sleeves 62 against axial rotation. To adjust the pitch of the wheels the clamping plates 74 are loosened and the sleeves 62'are rotated until the wheels are in the desired angular relationship to the tube (for example, as shown inFigure 3) and then the plates 74 are tightened to hold the sleeves in place.

Each of the shafts 56 is secured by a universal joint 76, provided to accommodate the adjustment of the wheels, to one of the three

drive shafts

78, and 82. The drive shaftsare connected by universal joints 84 to the shafts 86, which are rotatably journalled in the support 88 and which carry the sprockets 90. The support "88 is bolted onto the top 38 and has a center opening 92 for the passage of the tube. The sprockets are driven by a chain 94 which is powered by a motor'96.

As shown in Figure 1, the motor 96 is mounted on the frame 42 and drives a double belt 98 which is connected to a double sheave 100. The shaft 102, which carries the sheave 100, has a sprocket fixed thereon over which the chain 94 is passed. A chain tightener sprocket 104 is engaged with the chain and is carried by a shaft 106, which projects from the frame 42. The shaft 106 powers a drive belt 108 which is connected by a pulley 110 to a jack shaft 112. The jack shaft is mounted by bearing blocks 114 on the frame and extends axially of the frame. A pulley 116 is fixed on the jack shaft and drives a belt 118 which through a larger pulley 120 drives the forming rolls, as will be described. A pulley 122 is also fixed on the jack shaft 112 and has a belt'124 entrained thereon. The belt 124 powers the outlet conveying section 16.

In the latter respect, the outlet conveying section 16 r includes a rotating cylindrical conveyor or barrel 126,

which is rotatably mounted in bearing collars 128. The bearing collars are vertically supportedby a frame (a portion of which is shown inFigure 1 along with one of the collars) and the barrel 126 is rotatable within the collars in axial alignment with the tubes moving axially through the working section. A pulley 132 issecured to the inner end of the barrel and is driven by the belt 124. The barrel rotates in the same direction as the tubes and receives the finned portions of the tubes, as the tubes leave the machine, for the purpose of supporting the tubes. Because the barrel rotates withthetube, there is little wear imposed on the finned surface. of the tube. In this regard, the barrel is rotated by the motor through the jack shaft and belt 124 at approximately the same speed as the tube is rotated by the motor through the

drive wheels

50, 52, 54, shaftings and chain drive. Thus, the barrel has the same R. P. as the tube.

A holder for a supply of fin stock is provided and, as shown in Figure 1, includes a drum 134 which is rotatably supported by a supporting block 136 so that the drum is free to rotate as the stock flu in strip form is unwound from the drum.

The frame 144 upstands from the top 38 and carries the slide member 142 between its sides, the slide member .of the frame 144 and to the holder 140. The holder Mil,

which carries the guide pulley 138 for the strip is thus mounted on the slide member 142 to tension the strip.

By means of the resiliently mounted holder the pulley floats on the slide member and absorbs any shock coincident with the holder and strip 150 thus avoiding accidental deformation or damage to the strip. As shown generally in F gure 1 and more specifically in Figure 6 the strip 150 1s passed through a funnel type guide 152 which is mounted vertically on the frame 144. The guide 152 is rectangular in cross section and is of a width to freely receive the strip which moves in flattened form therethrough. The lower end of the guide 152 is turned inwardly to turn the strip from a vertical to a horizontal plane. As the strip exits from the guide 152, it is passed :Erougfh :a means for corrugating one longitudinal edge ereo i As shown in Figures 6 and 7, the edge 150a of the strip is transversely corrugated, while the remaining portion and opposite edge is left smooth. The corrugated edge 1501: of the strip constitutes the tube edge thereof or the inner peripheral edges or bases of the fins formed by the spiral winding of the strip on the tube 36. Only the edge 150a is corrugated by means of a pair of cooperating corrugating rollers 154 and 156. The rollers are rotatably journalled on shafts which project laterally from a support 158 that is carried by the frame 144 and which also carries the guide 152. The corrugating rollers are disposed in vertical alignment with the

teeth

154a and 156a in meshing engagement. The roller 156 is provided with a smooth cylindrical extension 158 which lies alongside the teeth 156a and projects beyond the end of the roller 154. The extension 158 is provided to support the edge 15011 of the strip, and thus, the uncorrugated portion of the strip.

As shown in the diagrammatic illustration in Figure 7, the teeth of the corrugated rollers form the corrugations in the edge 150a by accurately displacing the material from the plane of the strip proper. From the corrugating rollers, the strip passes through a channel guide 160,

the channel passage of which is vertically disposed and thus, turns the strip 90 from a horizontal plane to a vertical plane. gated edge 150a adjacent the exterior of the tube so as to form the tube side edge of the strip or inner peripheral edges of the fins.

As shown in Figures 8 and 11, the strip 150 is guided by the channel 160 toward the underside of the rotating tube 36, and positioned beneath the tube 36 to act on the strip 150 as it advances under the tube 36 in the The channel 160 positions the corru- 1 iii forming head unit. Such unit includes a pan roll 162 and a small cooperating roller 164, with a backup roll 166 being provided for the small roller 164. The pressure between the pan roll 162 and the roller 164 causes the strip to be unreeled from the drum 134.

The backup r-oll 166 is horizontally disposed above the surface 38 and is provided with an integral depend- .ing. shaft 168 as shown in Figure 14. The shaft is rotatably supported by bearings 170 in a block 172 which upstands from the surface 38. A pulley 174 is fixed on the shaft above the lower end thereof which is rotatably journalled in a collar 176 on the frame 42. The pulley 174 is connected by a belt 178 to a pulley 180 which is hori- 3:

zontally carried by a shafting 182 below the top or surface 38. The shafting 132 projects from a gear reduction unit 184 from which an input shaft 186 laterally projects and is provided with the pulley 120. The shaft 168 and the shafting 182 are driven by the motor 96 I "from. The shaft 190 carries the pan roll 162 which is integral therewith.

plate 196 which is interposed between the backup roll 166 and the pan roll 162 in a manner and for a purpose to be described. As shown in Figure 9, the channel guide 160 is integral with the plate 196 and one side 198 of the channel guide extends beyond the opposite side 200 in a manner to confront in spaced relation the face 202 of the plate 196. The side 198 of the channel guide is not attached to the face 202 which is spaced therefrom so that the strip moves between the side 198 and the lower portion of the face 202. The side 198 terminates at the roller 164 so that the strip is lead directly by the channel guide, particularly the side 198 in cooperation with the portion of the face 202, over the protruding peripheral portion of the roller 164; In this respect as shown in Figure 14, the diameter of the roller 164 is slightly greater than the width of the plate 196 so that the roller protrudes or extends beyond the opposite faces of the plate 196 and is in contact with the periphery of the backup roll 166 and thejpan roll 162. The strip passes between the contacting peripheries of the pan roll 162 and the roller 164 and the outer peripheral edges of the fins or uncorrugated outer edge of the strip is rolled or extruded by the pressing coaction of the pan roll. and the roller 164. At the time that the strip is subjected to the rolling or extruding action of the pan roll and. the roller 164 the corrugated edge 150a is in contact with the underside of the rotating tube 36 and thestrip is in the commencement of the tin forming process. Thus, the strip is rolled o-r extruded so as to force the inner corrugated edge 150a into contact with the tube and to relieve the outer periphery of the fin proper of any strain and thereby create a smooth spiral fin as the strip is being wound on the tube 36.

The pan roll 162 is mounted for bodily adjustment relative to the roller 164 so that the amount of pressure exerted by the pan roll and roller 164 on the strip can be adjusted. In other words the pan roll and the roller are relatively adjustable both towards and away from each unit. The pan roll is also mounted for adjustment about an axis transversely to the axes of rotation of the rolls and roller so as to adjust the angle of deformation of the strip.

Such adjustable mounting structure is shown in Figures 13 and 14- wherein it will be noted that an opening 204 is formed in the surface 38 and receives: the depending hub portion 206 of a plate 208. The plate is hingedly mounted at one end on a pivot rod 210 which is supported by lugs 212 that upstand from the surface 38. The plate is locked in a tilted position of adjustment about the pivot rod by a bolt 214 which is threaded vertically through the opposite end thereof and extends through a threaded opening 216 in the surface 38. A bolt 218 is threaded vertically through the plate adjacent the bolt 214 and is held in adjusted positions by a locknut 220. The bolt 218 rests on the surface 38. Thus, to adjust the angle of tilt of the plate 208 and thereby the angular relationship between the pan roll 162 and the roller 164, that is the angle of deformation of the strip, the bolt 214 is unscrewed from the surface 38 and the bolt 218 is axially adjusted to set the plate 208 in the desired angle. The bolt 214 is then threaded into the opening 216 to lock the plate in such set position.

The shaft 190 of the pan roll 162 is rotatably mounted by ball bearing assemblies in an eccentric hub 222, which is mounted within the hub 206 of the plate 208 by an arm 224, which radially projects therefrom and extends beyond the periphery of the roll 162. The outer end of the arm 224 is disposed between a pair of axially aligned set

screws

226 and 228. The set screws are carried by ears 230, which upstand from the plate and receive the set screws. It can be seen from a consideration of Figure 13 that the relative axial movement of the set screws controls the rotation of the eccentric hub which will ad- 7 vancezthe periphery of the pan roll towards and away from. the periphery .of .the. roller 164.

It will be particularly. noted that the upstanding annu- ..lar periphery .232 of the panroll is slightly inclined out- -wardly. from the bottomrof the roll so as to -engage the .roller.16,4.at -a.slightangle and thereby roll and extrude the interposed strip, without flattening the corrugated .edge.1 50a. In. this respect, the upper edge 234 of the -peripheralxportion of the pan roll is V-shaped or'at least the outer portion of. the upper end isprovided with a re- ..lief angle and,.similarly, the upper edge portion of the .smallroller-164 is converged at an angle. Therefore, the upperouteredge .of'the peripheral portion of the pan .rolland the upper edge of the roller 164 are cut back at :an angle so as to permit the corrugated edge 150a to pass .therebetween without beingsubjected to the rolling or extruding action.

Asishownin Figures 4 and 5,.a plate 236 is vertically mounted on the block 172- on the table top surface 38 .andlis provided with a suitable cutout portion 238 to accommodate a portion of the periphery of the backup .roll 166 .which bears against thesmall steel roller 164 .and provides the necessary pressure to withstand the pressure imposed on the roller by the pan roll. The plate 236 is also formed with a circular opening 240 throughwhichthetubepasses. Guide rollers 242 and .1244 vare mounted on the front face of the plate 236 and vprojectinwarclly of the opening 240 to engage the rotating tube and stabilize the tube as it passes over the tabletop 38, and particularly over the forming roll unit as. the strip isbeing wound.

The rollers .242 and 244 are rotatably journalled on

suitable shafts

246 and 248 which extend through the plate 236 and are attached to the guide plate 196. The guide plate 196 is formed with a circular opening 250 to=accomtnodatethe:axialpassage of the tube 36 therethrough. The face 202 of the plate 196 is formed with aspiralcam 252 whichis concentric to the opening 250 in the plate. The cam surface 252 starts at the roller 164 as shown'in Figure 9, andspirals around the opening back to its terminatingrlowtpoint at the channel passage. The purpose of theispiral cam surface is to guide the fins, as .shownrinFigure 11,.around the tube, after the strip has been rolled or extruded by the forming roll unit.

Cooperating with the guide plate 196 is a fin following guidemember 254, which is hinged bya pin 256 to the projecting end 258 of the plate 196. The pin 256 is threaded and the following guide member 254- is locked .in.place:by-a.nut.260, which is threaded on the threaded shankofthe pin256. The fin following guidemember 254 has a handle..262 which extends above the plate 196 .so that when -the nut 260 is loosened the fin following ,fguide-membercanbe swung about the pin 256. The fin zfollowing guidemember has a concave recess 264 .formedin its;lower.edge to provide clearance for the tube .36. The edge 2660f therecess is beveled.

As shown inFigure 9, the inner end of the side 198 is .concaved,as.at.199,.to.provide clearance for the periphcry of the pan roll and enable the periphery of such roll to'contactthe roller 164, with the bite of the roll and roller.immediatelydisposedatthe exit end of the channel guide passage. The purpose of the beveled edge 266, as shown inFigure 12, is to avoid mashing the corrugated inner edges or bases 1500: of the fins. The outer portions of thefins, as shown in Figure .12, pass over the spiral cam surface252 and also over the inner face of the .fin following guide member .254. Therefore both thebeveled edge 266 of the concave recess 264 and the beveled inner peripheral edge 268 .of the cam 252 are necessary to permit the outer peripheral portions of the fins'to slide over the cam and the face of the fin followingguide member, without the corrugated inner periph- "eral'edgesor bases of the fins contacting such members.

The plate 196'has a'laterally projecting pin 270 and thefinfollowingguide member has a notch 272 which "se'ats'onthe pin to locate the fin following guide member suitable substance, such as solder or the like.

I8 inthe properhorizontal position. To ass'istin thezguidin'g of the-str ip inits-fin forming Windings'around the tube,

:the. inner face ofthe fin following, guide member is provided with an integralhook 274,-the portion 276 of which has aflattened inner-surface which parallels the faceof the member. A pin 278 projects laterally from the inner faceacross the concave recess from thehook 274 and carries a finger 280. The finger =2-80 has a'hub portion 282 which-is rotatablypositioned on the pin and held in ad usted positions by a radial setscrew 24. Thus, the hook 274 is adjustable to various positions ,on the face. The purpose of the hook and finger which cooperate together is best shownin Figure 11 wherein it will be noted that such members cooperate to hold the outerperipheral portions of thefins in guided contact with the flat inner face of the fin following guide member.

While the operation of the machine is believed clear from the drawings, a-brief description of the operation will be given. T hus, considering Figure 1, it will be understood that the tube 36.is fed-from trough 18 through the working section, where it is finned, to the rotating outlet conveying barrel 126. Before the tube is passed to the drive means for movement through the working section the exterior surface of thetube is coated with a This is not necessary for the purpose of causing an adherence between the'corrugated inner peripheral edges or bases of the fins with the extruded surface of the tube but'is more for the purpose of ensuring an intimate heat exchange contact between the fins and the tube, avoiding airigaps. Thetube-is, of course, moved axially vwhile being rotated about its axis by the adjustable drive means and the pan roll and backuproll are rotated, thus rotating the interposed small steel roller, at exact synchronized speed with thespeed of rotation of the tube. The end of the strip is manually fixed or attached to the exterior surface of the tube preparatory to theautomatic operation of the machine.

The rotation of the tube will, of course, wind the 'strip in fin formations on the exterior surface of the tube after the strip has been partially corrugated and passed through the forming headrolls. The forming head rolls deform the fin strip in an exact ratio of the fin tube outside diameter to the tube outside diameter. Thus, the fins will have a very low corrugated base and the outer peripheral portions of the fins will be extremely smooth. The relationship between the speed of the axial movement of the tube and the cam surface 252 will control the pitch of the fins on the tube, each fin being identicallypitched and evenly spaced from its companion fins. The portion of the tube'that has been finned and passed beyond the forming roll unit enters the rotating barrel 126 which supports the tube and ensures against the imposition of wear on the finned surface.

While this machine has been'designed to forma smooth fin with a very low corrugated base or inner peripheral edge, the same machine can form a perfectly and entirely smooth fin by removing the relief angle of the top edge of the peripheral portion of the pan roll and the top edge of the small roller and omitting the companion corrugating rollers.

Thus, while the preferred form of the invention has beendescribed herein and illustrated in the accompanying drawings, other'forms may be realized as come within the scope of the appended claims.

I claim:

1. A device for wrapping a strip on edge spirally around the exterior of a longitudinally moving and rotat- 111g tube to provide spiral, spaced heat exchange fins exteriorly on the tube comprising drive means for longitudinally feeding and rotating a tube having one end of a strip aifixed on edge to its exterior surface, means for rolling the strip as it initiates the formation of fins on the tube, guide means around-the tube and through which the tube passes receiving the strip from said'roiling means and guiding it around the tube, while maintaining it in its roller condition, a rotatable guide cylinder axially aligned with the tube following the fin formation and guidingly receiving and supporting the finned tube, motor means, and a drive transmission means connected between the motor means, the drive means for the tube, the strip rolling means and the guide cylinder, said drive transmission means commonly actuating the drive means and the rolling means so that the rolling means rotates in the linear movement therethrough of the strip in synchronized speed with the rotational speed of the tube as the strip is being wound on the tube and the drive transmission means rotating the guide cylinder in the same direction and at approximately the same speed as the tube is rotated to prevent wear being imposed on the fins of the tube.

2. A device for wrapping a strip on edge spirally around a tube to provide heat exchange fins exteriorly on the tube comprising, a drive means for axially rotating and longitudinally feeding a tube having an end of a strip affixed on edge to the exterior thereof and adapted to wind the strip spirally on edge around its exterior surface as it rotates, resiliently tensionecl guide means for the strip, means for transversely corrugating one longitudinal edge of the strip as it passes from the guide means to the tube with such corrugated edge forming the inner peripheral edges of the fins, means disposed adjacent the tube. for rolling the uncorrugated portion of the strip as it initiates the fin windings on the tube, guide means through which the tube passes disposed adjacent said last means and receiving the strip therefrom to guide the strip around the tube in forming the fins while maintaining the strip in its stressed condition, a rotatable guide cylinder axially aligned with the tube and receiving the tube following the formation of fins thereon, motor means and a drive transmission means connected between the motor means, the tube drive means and the cylinder for rotating the tube and the cylinder at approximately the same rate of speed and in the same direction.

3. In a device for forming spiral heat exchange fins on a longitudinally moving and axially rotating tube; means for guiding and forming a strip as it is wound around the tube responsive to the rotational movement of the tube, said means comprising a small roller rotatably positioned vertically below the tube, a pan roll positioned adjacent said roller and having a peripheral flange disposed alongside the roller and cooperating therewith to roll the outer edge of the strip and force the inner edge into contact with the tube as the strip is being wound on the tube, a backup roller engaging the small roller and positioned on the opposite side from the pan roll, said roller and backup roller being rotatable about parallel axes perpendicular to the tube, and means mounting the pan roll for bodily curvilinear adjustment toward and away from the small roller about an axis at right angles to the axis of rotation of the small roller and for rotation about an axis, substantially parallel with the axis of the small roller and adjustable relative to and away from the small roller whereby the amount of pressure exerted by the pan roll and the roller on the strip can be adjusted and whereby the angle of deformation of the strip can be selectively adjusted.

4. A device as claimed in claim 3, wherein said peripheral fiange is slightly inclined outwardly toward the small roller so as to engage the roller at a slight angle and said flange has a V-shaped outer edge and said roller has an upper end cut back at an angle so that there is a space between the upper end of the roller and the outer edge of the flange for free passage of the inner edge of the strip between the pan roll and the roller.

5. A device as claimed in claim 3, wherein a support is provided transverse to thetube and through which the tube passes, said support carrying the small roller and 10 having a face formed with a spiral guide surface for the strip as it is initially wound on the tube and channel guide means carried by the support and positioned so as to guide the strip right up to the bite of the pan roll and the small roller below the tube at the initial point of contact between the strip and the tube.

6. A device as claimed in claim 5, wherein an arm is mounted above and transversely of the tube and is movable towardand away from the tube into a position confronting the face of the support, said arm having a guide surface on its side confronting said face which cooperates with the guide surface on the support and having an 'opposite side provided with a guide means for engaging and guiding the outer edge of the strip after it has been wound on the tube.

7. A device as claimed in claim 3, wherein a table top is provided below the tube and said last means includes a plate hingedly mounted at one end on the table top and movable vertically about a horizontal axis, means carried by the other end of the plate in cooperation with the table top for setting the plate in selected positions, said plate having a vertical opening coinciding with a vertical opening in the table top, an eccentric hub rotatably mounted in the plate opening, a shaft for the pan roll mounted in the hub, an arm radially extending from the hub parallel with the top of the plate and beyond the pan roll and adjustment means on said plate in engagement with the arm to rotate the arm and hub and lock the arm and hub in selected positions.

8. In a device for forming spiral heat exchange fins on a longitudinally moving and axially rotating tube; means for guiding and forming a strip being wound on the tube responsive to the rotational movement of the tube, said means comprising a vertical support arranged transversely of the tube and having an opening through which the tube passes, said support having a face formed with a spiral cam concentric to the opening over which the strip passes as it is being wound on the tube, a channel guide means carried by the support tangently to the cam and leading almost directly up to the starting low point of the cam so as to guide the strip immediately up to the cam, a guide arm coperating with the cam and disposed in confronting relation at one side therewith, said guide arm having an opposite side provided with guide means for engaging the outer edge of the strip and guiding the fins after they have been formed on the tube, and means disposed below the opening at the end of the channel guide means for rolling the outer edge of the strip at the moment the inner edge of the strip contacts the tube.

9. A device as claimed in claim 8, wherein said channel guide means includes a first vertically disposed arm extending laterally from the plate fiush with the face thereof, a second vertically disposed arm spaced slightly from and arranged parallel with the first arm and extending inwardly beyond the first arm and arranged in confronting relation with said face of the support.

10. A device as claimed in claim 8, wherein said guide arm is movable vertically above the tube toward and away from the tube and said guide means on the opposite side thereof includes a fixed finger and an adjustable firger disposed in spaced confronting relation with said s1 e.

11. A device as claimed in claim 8, wherein said lastnamed means includes a small roller, said support having a cut-out formed below the opening and in which said roller is vertically positioned for rotation, said roller being d1sposed intermediate the end of the channel guide means and the starting point of the cam and being of a diameter slightly greater than the thickness of the support, a cooperating pan roll engaging the small roller on the cam side of the support and a backup roller engaging the small roller on the other side of the support, the bite between the small roller and the pan roll being disposed right at the end of the channel guide means.

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