US3005253A

US3005253A - Manufacture of heat exchange tubing

Info

Publication number: US3005253A
Application number: US763514A
Authority: US
Inventors: Iii Herbert J Venables
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1958-09-26
Filing date: 1958-09-26
Publication date: 1961-10-24
Anticipated expiration: 1978-10-24

Description

Oct. 24, 1961 H. J. VENABLES m MANUFACTURE OF HEAT EXCHANGE TUBING Filed Sept. 26, 1958 7 Sheets-Sheet 1 FIGJ IO 46 a 2 "g g g 65 3 I 41 r 6 ll: I i\ 62 I Is 9 e 27 A /k INVENTOR.

HERB RT I YENABLES III BY g zc n.

H is ATTORNEY Oct. 24, 1961 H. J. VENABLES m 3,005,253

MANUFACTURE OF HEAT EXCHANGE TUBING Filed Sept. 26, 1958 7 Sheets-Sheet 2 INVENTOR.

HERBERT J. VENABLES 1J1 Hi5 ATTORNEY Oct. 24, 1961 H. J. VENABLES m MANUFACTURE OF HEAT EXCHANGE TUBING 7 Sheets-Sheet 3 Filed Sept. 26, 1958 FIG-.4

INVENTOR.

HERB RT J. VENABLES JIL BY HIS ATTORNEY Oct. 24, 1961 H. J. VENABLES m MANUFACTURE OF HEAT EXCHANGE TUBING 7 Sheets-Sheet 5 Filed Sept. 26, 1958 m R0. R5 N. n mm o0 B mwfm mo. M w: Mm m I m w: m 6 E H E m @E w m m ho. m B Q m r w. J ifi. i F: r 0 1 H V o k m w 5i M. a2 Ifi H & .81 v h. N: wz TV Q Q L 2 HIS ATTORNEY Oct. 24, 1961 H. J. VENABLES Ill MANUFACTURE OF HEAT EXCHANGE TUBING 7 Sheets-Sheet 6 Filed Sept. 26, 1958 FIGJO m R L W5 A MN 5 v I. T R E B R E H HIS ATTORNEY Oct. 24, 1961 H. J. VENABLES 111 3,005,253

MANUFACTURE OF HEAT EXCHANGE TUBING Filed Sept. 26, 1958 Sheets-Sheet 7 F'IG.H

li Ill! 5 Wllllll|||||||||||||||||||||"I!" i -i? 59 F I i v .v 7&\\ i1 W 58 M 3 INVENTOR. 5 HERBERT :r. VENABLES I11 1 i BW HIS ATTORNEY United States Patent C) Filed Sept. 26, 1958, Ser. No. 763,514 Ciaims. (Cl. 29-33) The present invention relates to the manufacture of finned tubing employed for heat exchange purposes and has as its principal object the provision of improved means for manufacturing heat exchange tubing of the type including a tubular member having helically wrapped thereon a fin material formed into a plurality of individual fin sections extending outwardly from a base flange.

In known machines for making finned tubing having fins of this type, a strip of fin stock is slit from one edge to form a plurality of individual fin sections connected by a base flange, bending the fin sections outwardly with respect to the base flange, and, while rotating and advancing the tubing, wrapping the fin material onto the tubing with the base flange in flat-wise engagement with the surface of the tubing and with the individual fin sections extending outwardly therefrom. These machines use suitable tension devices to avoid breakage of the fin stock during wrapping. Because of the need for these tensioning devices, it has been necessary to rotate the tubing rather than the fin stock and the fin forming mechanism due to the fact that centrifugal forces would interfere with the proper operation of the tensioning means. As a result, only short lengths of tubing could be wrapped, the length being limited to that which could be rotated as it passed through the wrapping machine.

The machine of the present invention comprises a rotatable head for carrying a coil of strip stock thereon and including an axial passage therein through which a tubular member is advanced. The machine includes a means for reducing the exterior circumference of the tubular member in order to provide a tube of continuously uniform circumference as it is advanced through the axial passage in the rotatable head. Means are provided on the head for removing strip stock from the coil and for forming the strip stock into a serrated fin material having an angularly disposed base flange. Means are provided on the head for wrapping the serrated fin material onto the tubular member with the base flange disposed in fiat-wise engagement with the circumference of the tubular member as the rotatable head is rotated around the tubular member. In order to maintain a constant tension on the fin material while it is being wrapped onto the tubing, the fin material forming means is operated at a rate to release fin material, for each revolution of the head, that is a predetermined amount less than is demanded by the helical wrapping requirement as constituted by the uniform circumference and governed lineal advancement of the tubular member.

For a better understanding of the invention, reference may be had to the accompanying drawings in which:

FIG. 1 is an elevational view of the machine of the present invention with portions of the machine broken away; M

'FIG. 2 is a plan view taken along line 2 2 of FIG. 1 showing the driving gear arrangement for driving the various components of the machine;

FIG. 3 is a plan view taken along line 3-3 of FIG. 1 showing the swaging rolls for reducing the circumference of the tubular member as is fed upwardly through the machine; A

FIG. 4 is a partial elevation view taken along line 4:-4 of FIG. 3 and illustrating the swaging and driving components;

FIG. 5 is a plan view looking downwardly on the ma- Patented Oct. 24, 1961 chine as shown in FIG. 1 and illustrating the rotatable head carrying the coil of fin stock;

FIG. 6 is a cross-sectional view of the rotatable head taken along line 66 of FIG. 5;

FIG. 7 is a cross-sectional view taken along line 77 of FIG. 6, showing the braking arrangement for preventing overrunning of the stock carrying table;

I .FIG. 8 is a partial plan view taken along line 8--8 of FIG. 6 also illustrating the braking arrangement for preventing overrunning of the fin stock carrying table;

FIG. 9 is a detail view illustrating one of the friction brakes for producing the drag on the coil carrying table with respect to the rotatable head;

FIG. 10 is a detail view fin forming, slitting and wrapping mechanism carried centrally on the wrapping head;

FIG. 11 is an elevation view taken along line 11-11 of l0 illustrating the flange forming operation;

FIG. 12 is a partial cross-section taken along line 12-12 of FIG. 10 illustrating the wrapping and tin sections straightening mechanism of the machine;

FIG. 13 is a schematic view illustrating the slitting operation and the tilt imparted to the fin sections during the operation;

FIG. 14 is a schematic view illustrating, in exaggerated form, the amount of fin material formed for a revolution of the head in relation to the reduced circumference of the tubular member; and

FIG. 15 is a greatly exaggerated cross-sectional view of a tubular member showing the shape it assumes when wound in coils.

Referring to FIG. 1 there is shown a machine for manufa'ctur'ing heat exchange tubing of the type having a discontinuous fin. The machine is supported on a base or bench 2 which carries the machine for rotation about a vertical axis. A suitable supply of tubular material, such as the large coil 3a, provides tubular material 3 which is fed vertically upward through the machine. Mounted within the base 2 of the machine is a tube feed and swaging assembly 4 which provides means for reducing the circumference of the tubing as well as for driving the tubing upwardly through the remaining components of the machine. Arranged on a top plate 6 of the base 2 is a drum supporting member 7 which supports a rotatable drum or spindle 8 for rotation about a vertical axis. The upper end of the rotatable spindle 8 carries a rotatable head 9 which in turn carries means for supporting a coil of sheet stock as well as a fin wrapping and forming assembly 10.

Means are provided for rotating the spindle 8 and, thereby, the head 9 about the vertical axis of the spindle 8. More specifically, the spindle 8 and the rotatable head 9 are driven by a motor 11 which, through a belt 12 or chain, supplies power to the main drive shaft 13. The shaft 13 extends downwardly into a gear box and, through separate gear chains, drives the rotatable drum 8; as well as the tube feeding and swaging assembly 4 in the lower portion of the base 2. More specifically, as may best be seen in FIG. 2, the shaft 13 provides power for rotating the spindle 8 through the large gear 14 which engages the gear 16 fixed on the revolvable spindle 8. As may be seen in FIG. 1, the rotatable spindle 8 is supported within the vertical support 7 by means of anti-friction bearings 17, which permit rotation of the drum and the rotatable head when power is applied to the shaft 13. A tubular guide 19 is disposed centrally within the spindle 8 and arranged to receive the tube 3 from the feed roll assembly 4 during the operation of the machine. The tubular guide 19 is rigidly and vertically supported by the top plate 6 and extends upwardly through an axial passage formed in the rotatable head 9. A bearing 18 provides support for the upper portion of the tubular guide which extends axially through the rotatable spindle on the rotatable head 9.

Referring again to FIG. 2, in order to drive the tube feeding and swaging assembly 4, there is provided a gear chain including the small gear 22 on the shaft 13 which drives an idler gear 23 keyed to a shaft 24 which in turn drives a chain of gears designated 25, 26, 26a and 27. Gear 26 is shown partially broken away in FIG. 2 in order to show that gear 27 is driven by the gear 2611 which is disposed below gear 26 and on the same shaft as gear 26. Gear 27 is secured to shaft 28 which is journalled in the top plate 6 and extends downwardly into the base 2 for driving the swaging and tube feeding assembly 4. As may be more clearly seen in FIGS. 3 and 4, the shaft 28 extends downwardly into the tube swaging and feed assembly 4 wherein it drives a set of swaging rolls, generally designated 29, and two sets of driving rolls designated 31 and 32 (driving rolls 32 are not shown in FIG. 4). p

The shaft 28 carries three worms 33 which are in mesh with three worm gears 34, that directly connect with feed roll drive shafts 36 and apply power to the first roll in each set of feed or swaging rolls. As may be seen in FIG. 3 all of the swaging rolls 29a, 29b and 29c are positively driven through a plurality of bevel gears 37 which form a chain around the swaging assembly 29. As may be seen in FIG. 3, the triangular arrangement of the three rolls 29a, 29b and 290 all positively driven through the bevel gear train, provides a compressive force substantially around the entire periphery of the tube 3 which is fed upwardly through the swaging assembly 29. The set of swaging rolls 29a, 29b and 290 are designed to reduce a particular sized commercially available tubing, when passedtherethrough, to a more nearly uniform or constant circumference. The purpose of the swaging operation will be more clearly explained later in this specification. It is contemplated that the swaging rolls be made of hardened steel or contain a hardened insert which willpermit a longer period of use. The assembly is also made easily removable and may be replaced when wear begins to reduce the accuracy of the swaging operation.

the configuration of the tubing nor do they change the size which has been obtained through the swaging or sizing assembly 29.

Tubing 3, after it has been sized in the swaging and tube feed assembly 4, is fed into the tubular guide 19, as shown in FIG. 1. This leads the tubing upwardly through an axial passage in the rotating head 9 where it enters the fin forming and winding assembly 10. As may be best seen in FIGS. 1, 5 and 6 supporting'means are provided on the rotatable head 9 for carrying the strip stock 41 in large circular-coils. In order to permit the strip stock to pay off of the coil 41 as the rotatable head 9 is rotated about the tube 3 being advanced upwardly through the rotatable head, it is necessary to provide means, rotatable with respect to the rotating head 9, that allows the strip stock 41 to pay off of the coil. More specifically, there'is provided a coil carrying table 42 which is mounted on the rotatable head 9 and which is free to rotate with respect to the head. The coil of strip stock rests on the table and is clamped at its inner diameter so that, for all practical purposes, there is no slippage between the coil and the table. A plurality of clamping dogs 45 secure the inner diameter of the coil stock with respect to the support table 42. As may be seen in FIG. 6, the table is mounted on rollers 43 that are arranged at many points around the rotatable head and coil. As may be seen in FIG. 5, the stock 41 passes around an idler roll 44 and then enters into a'turret 46 in which is mounted the forming and wrapping assembly. The strip material is twisted degrees after it leaves the idler roll 44 before it is pulled into the turret 46.

Referring to FIGS. 10, 11 and 12 there is shown, in greater detail, the forming and wrapping assembly which receives'the strip stock 41, forms it and wraps it onto the tubular member advancing upwardly through the rotating head. Means are provided within the turret 46 for forming a base flange on the strip stock 41 and for lancing the strip inwardly from one end to form'separate or discontinuous fin sections. The tubular guide 19 extends upwardly through a cavity or axial passage in the rotatable head 9 and the turret 46 and directs the tubular member 3 into the rotating wrapping assembly. At the upper end of the tubular guide is a fin straightening head (seen best in FIG. 12) generally designated 47. Associated with the fin straightening head 47 are means for wrapping the formed and slit fin material onto the tubular member 3 as itadvances through the wrapping head. As the strip stock 41 enters the turret 46 it is directed by a guide 48 into the hem or flange forming means. In

the present invention, the flange forming means comprises a single pass of three forming rolls having their axis in one vertical plane and constituting a single line of tangency which describes a right angle. More specifically, the forming means comprises a lower roll 49, an upper roll 51 and a cone-faced roll 52. These rolls form the flat strip stock 41 into a right angular section. As the strip stock 41 approaches the upper and lower rolls, which grip the stock along its major width the right hand edge of the strip 41, as seen in FIG. 11, abuts against the flange 53 on the upper roll 51 which serves to guide the strip through the forming rolls. As. the strip approaches the forming rolls, the cone-faced roll SZengages the left hand or the outwardly extending edge of the strip material and. provides a continual trend or force against the free left edge of the strip stock 41. The resulting confinement causes the free edge of the strip to roll clockwise until a common tangency is reached between a portion of the upper roll 51 and the cone-faced roll. The flange 53 on the upper roll 51 opposes the horizontal component of force exerted by the conical roll 52 thereby causing compression of the strip 41 and assisting the formation of the hem 54. The above described hem 54 forming means also exerts a slight pull or tension on the strip stock- 41 for removing the stock from the coil.

As the strip stock 41 leaves the hem forming means, itpasses through a guide 56, best seen in FIG, 10, and is directed into a means for slitting the major width of the stock into'a plurality of separate fin sections. The'slitting means comprises an upper lancing or slitting roll 57 and a lower lancing orslitting roll 58 (best seen in FIG. 11)

each of which contain a plurality of cutting teeth for slitting the strip 41 from its right hand edge, as seen in FIG. 10, to a point adjacent the hem 54 of the strip. As can be seen in FIG. ll, the hem 54 of the strip, which has been turned upwardly with respect to the remaining portion of the strip stock, rides flush against the face of the upper lancing or slitting roll 57 while the remaining portion of the strip stock is slit into a plurality of discontinuous fin sections 59. x I Y Means are provided for driving the forming and slitting rolls intimed relation with the rotation of the rotatable head 9. More specifically, as may be seen in FIG. 1, in order to drive the slitting and forming means, there isprovided' on the tubular guide 19, which, as stated before, remains stationary with respect to the rotatable head 9, a sun gear 60 having its gear teeth in mesh with a planetary gear 61 journalled in the rotatable'he'ad. As the'head rotates about the tubular guide 19 and the sun gear 60, the gear 61is turned 'with respect to the head 9 and it, in turn, imparts rotational power to the shaft 62 journalled in the head; Upwardly from the gear 61 on the shaft 62 is a gear 63 which meshes with a gear 64 and imparts rotation to a worm shaft 65 extending upwardly into the turret 46. As may best be seen in FIG. 10, the worm shaft 65 carries a worm 66 which meshes with the worm gear '67. Worm gear 67 rotates the lower lancing roll 58 (not seen in FIG. through a shaft (not shown) which lies directly below the upper lancing roll shaft 68 and which is exactly the same as the upper lancing roll shaft except that it carries a pinion gear 69 shown in dotted lines. Pinion gear 69 drives idler 71 and this in turn drives the gear 72 (shown in FIG. 11) on shaft 73 to apply power to the lower forming roll 49. Driving gear 74, also attached to the lower forming roll shaft 73 and rotatable therewith, engages a gear 76 on the upper forming roll shaft 77 to drive the upper forming roll 51. The cone-faced roll is driven by a means of a pair of intermeshing bevel gears 78 and 79 mounted respectively on the face of the lower forming roll 49 and the cone-faced roll 52.

In the illustrated embodiment of the invention there is no direct power supplied to the upper slitting roll 57. Instead, this roll is positioned such that it is driven through the fin stock by the cutting teeth of the lower slitting roll as these teeth slit the individual fin sections 59. In other words, as may best be understood by reference to FIG. 13, the meshing of the slitting teeth of the upper and lower slitting rolls 57 and 58 respectively causes the upper roll 37 to be driven through the material by the lower slitting roll 57.

The strip material 41 after being formed into a plurality of separate discontinuous fin sections 59 connected at the hem or flange portion 54 is directed around a turn-around roll 86 which is journalled into the bottom of the turret. The turn around roll 86 is free to rotate with the fin material passing around its outer surface. After passing around the turn-around roll 86, the previously formed fin material is directed into a means for winding the material onto the surface of the tube 3. More specifically,

' the fin stock or fin material passes through a guide 87 and is then Wrapped onto the tube as the tubing is advanced through the fin straightening head 47 of the tubular guide 19. All of the components within the turret 46 are rotating, along with the rotatable head 9, around the tubular guide 19 and the tube 3 advancing upwardly therethrough. The rotation of the head 9 causes the fin material to be helically Wound around the tube 3 as the tribe advances through the fin straightening head 47.

Referring now to FIG. 12, it may be seen that, as the tube advances through the fin straightening head 47, it passes through an adhesive cavity 88 which applies to the surface of the tube a rubber base or other type adhesive for binding the fin material to the tube 3. Adhesive is pumped or supplied to the adhesive cavity 88 through a feed tube 89. it should be mentioned that the inner diameter surface of the head 47 is splined to permit the adhesive to be retained on portions of the tubing as it passes therethrough while still providing annular support for the tubing during wrapping. As the tubing is fed up wardly through the fin straightening head 47, the strip or fin material is wound helically onto the tube with the hem 54 or base section of the fin material in flat-wise engagement upon the surface of the tube 3 and With the hem pointing upwardly. The adhesive squeezes out from between the tubing and the hem and fills any space between adjacent wrappings of the material.

Referring now to FIG. 13 there is shown in exaggerated form, the slitting rolls 57 and 58 as they lance the individual fin sections 59. It should be note that each section 59 is canted at an angle with respect to the original horizontal surface of the fin material 41. It has been found that these canted fin sections are not as desirable in the finished heat exchange tubing as sections which are arranged to present less resistance to air flow. Moreover, these canted fin sections make the wrapping of the fin material somewhat diflicult in that they tend to hang up on each other and various components of the machine. Therefore, the present invention provides a means for straightening these individual fin sections with respect to the plane of the material. More specifically, there is provided on the fin straightening head 47 an inclined surface 91 which, in combination with a beveled surface 92a of the straightening roll 92, straightens the individual fin sections as they pass between the surfaces. The straightening roll 92' rotates around the tubing, along with the remaining components of the turret and the rotatable head 9, and is powered so that the edge 93 thereof is actually or practically stationary with respect to the surface of the tube directly adjacent thereto. That is, the straightening roll 92 is poweredby a gearing arrangement which drives it at such a speed that the outer periphery or edge 93 of the straightening roll 92 is practically stationary with respect to the surface of the tube. As each successive fin section is drawn toward the tubing 3 it is engaged by the conical face 92a of the straightening roll 92. The fin sections are each successively passed between the surface of the straightening roll and the inclined surface 91 of the fin straightening head and the cant in each section 59 is ironed out by the twist imparted to each section 59 due to the action of these two surfaces. It should be noted that the straightening roll 92, although it runs flush with or brushes against the hem, does not exert any appreciable pressure on the hem against the tubing. That is, there is no compressive force or any other force applied to the fin material except the tension in the hem 54 of the material to cause the fin material to wind onto the tube 3. The roll 92 only acts on the individual fin sections to straighten the tilt in these sections during rotation of the roll about the tube 3.

In order to rotate the straightening roll 92 there is provided a gearing arrangement or means operated in timed relation with the rotation of head 9 and similar to that used for driving the forming and slitting means. This driving arrangement may best be seen in FIG. 11. Above the sun gear 60 on the upper end of the tubular guide 19 there is provided a second, but smaller, sun gear 94. This engages a planetary gear 96 on a shaft journalled in the lower portion of the turret 46. Rotation of the planetary gear 96, during the rotation of the rotatable head 9 and turret 46 around the tubular guide 19, operates a small pinion gear 97 directly above the planetary gear 96. Pinion gear 97 drives a gear 98 on the lower portion of the shaft 99 which, in turn, rotates the gear 101 on the upper portion of the shaft 99; Gear 101 intermeshes with the pinion gear 102 of the straightening roll drive shaft 103. Drive shaft 103 is mounted in an adjustable collar 104 to permit raising or lowering of the roll 92.

As stated before, the coil carrying table 42 rotates with the head 9 but is also supported on rollers to permit the table to rotate independently of the head 9 in order to pay off strip stock 41. In order to maintain a positive tension in the strip stock as it pays off of the coil and to assure rotation of the coil carrying table 42 with the rotatable head 9, means is provided for creating a drag or braking effect on the rotation of the support table 42 with respect to the head. By promoting a tension in the strip stock 41 as it pays off of the coil, the coil is maintained tightly Wrapped and prevented from uncoiling or hooping because of the centrifugal force acting on the coil during rotation of the head. More specifically, there are provided a plurality of braking means arranged in Archimedes fashion around the coil support table. As may be more clearly seen in FIG. 9, each of these braking means comprises a friction shoe 106 having its surface riding on the outwardly extending table 107 of the rotatable head 9. Each of these friction shoes 106 is forced downwardly against the table 107 by means of a plunger 108 which is depressed into the support table 42 by'the coil of strip stock 41. The plunger 108forces the spring 109 into greater compression and this causes the shoe 106 to 'does not exceed a predetermined value.

exert a'greater frictional force against the rotation of the coil carrying table 42. 7

As may be seen in FIGS. '6 and 9', when the fin stock 41 pays oif from the coil and is removed from that portion of the support table 42 above the plunger 108, the plunger is forced upwardly by the spring 109 releasing the compression of the spring and vastly reducing the frictional drag of the shoe. As may be seen in FIG. 5, each of these friction brakes is arranged in an Archimedes spiral around the coil support table and the brakes are therefore, progressively, released as the strip stock pays off of the coil. This, in turn, reduces the braking force on the table 42 as the strip stock is relinquished from the table thus reducing the amount of pull necessary to remove strip stock from the coil. It is desirable to gradually reduce the amount of braking force on the table as the radius of the coil reduces in order to maintain a nearly constant tension in the strip stock 41 as it pays off of the coil. If the braking force were not gradually reduced as the diameter of the coil decreases, the moment of force created by the tension in the strip stock and the radius of the coil would, then, necessarily have to be a constant force to overcome the braking effect. In such a case, the tension in the strip stock 41 would increase to compensate for the gradual reduction in the radius of. the coil, and the tension in the strip stock 41 necessary to overcome the braking effect would, when the diameter of the coil was greatly reduced, break the strip stock. Furthermore, as the diameter of the coil reduces, the centrifugal force on the individual loops of the coil reduces and there is less tendency for hooping and this also reduces the amount of tension needed in the strip stock as it feeds from the coil. In passing, it should be noted that the drag or braking effect created by the frictional brakes has nothing to do with the tension provided for wrapping the fin material onto the tube. The wrapping tension is entirely provided by the forming means in a manner to be explained later in this specification.

Since the table 42 is free to rotate with respect to the head and since the mass of the table is great, especially when carrying a full coil of strip stock 41, a tremendous rotational inertia exists in the rotating support table 42 and it is necessary to provide some means for preventing overrunning of the support table 42 when the rotatable head 9 is being stopped. It should be mentioned that this momentum or inertia, tending to cause overrunning of the table, greatly exceeds the amount of braking force exerted by the frictional brakes 106 on the table 107. Thus, a positive braking force is necessary to prevent the overrunning of the table when it is necessary to stop the rotating head 9. This is provided, as can best be seen in FIGS. 7 and 8, in the form of an eccentrically mounted circular wedge or camming brake 111 which is in contact with a brake flange 112 extending downwardly from the table 42. The camming brake 111 is arranged on a shaft 113 which extends through the table 107 of the rotatable head 9. On the opposite end of the shaft 113 is a lever arm 114 which rotates the shaft 113 and the eccentric wedge 111. The lever arm 114 is biased in a direction to prevent braking of the eccentric 111 by spring 116 connected in tension between the outer end of the lever arm 114 and the stud 117 extending from the lower surface of the table of the rotatable head;

In operation, the eccentric camming brake is designed to permit the flange 112 to rotate with respect to the rotatable head 9, or with respect to the table 107 on the rotatable head, as long as .the amount of friction Thus, the tension of the spring 116 through the lever arm 114 exerts a force against the eccentric to permit the flange 112' to rotate so long as the friction between the flange and the eccentric does not exceed'a predetermined value. I This permits a uniform relatively slow feed off of strip stock 41. But, whenever there is a tendency for the support table 42 to overrun the speed of thehead 9, the friction between the flange 112 and the eccentric wedge111 overfor the material and the material breaks. .cially true when the fin material has been formed into comes the moment of force exerted by the spring 116 and the lever ar-m 114. The wedge or camming brake then immediately turns in a direction to stop the rotation of the support table 42. As the camming brake 111 turns, the flange 112 is wedged between the wedge 111 and the back up roller 118 on the opposite side of the flange and the increased friction developed between the eccentric and the flange 112 stops the rotation of the support table 42 with respect to the head 9.

As stated previously, the forming means, or the hem flanging and slitting rolls, removes for each rotation of the head 9 a predetermined length of strip stock 41 from the coil and forms it into fin material. Referring to the schematic drawing of FIG. 14, it can be seen that the forming means, or the flanging rolls 49 and 51 and slitting rolls 57 and 58 are purposely geared to remove from the coil of strip stock a length of strip stock equal to the amount A for one revolution of the head. This same length A of strip stock is formed into fin material and supplied or released for wrapping during each revolution of the head. However, the projected helical length of one revolution about tubular member is equal to the length designated B in FIG. 14. Of course, FIG. 14 greatly exaggerates the difference C between the lengths A and B, but it is obvious from the drawing that the fin material must be elongated or stretched between the forming means and the point where it is wrapped onto the tubing during the wrapping procedure. It should be pointed out that, after a few revolutions of the head, the amount of elongation of the material between the forming means and the point of wrapping for each revolution, or the amount C, is wrapped onto the tubular member for each revolution of the head. That is, the percentage of elongation of the material between the forming means and the wrapping point approximates but never exceeds the percentage of elongation necessary to wrap a length A, which is formed during one revolution of the head, onto the helical length B of one revolution of the tubing. Therefore, by maintaining the elongation C within the permissible limits of elongation of the fin material for one turn around the tube 3, it is possible to continuously wrap the fin material at a precalculated tension, i.e., the tension produced by the elongation. For example, it is contemplated that, for a inch diameter copper tubing, the forming means will release about 1% less fin material for each revolution of the head than is required to completely wrap around the circumference of the tubing in a helical fashion. This is approximately .012 inch less fin material than is required to helically Wrap around the circumference of the tubing. Thus, in this case the length C amounts to .012 inch and this would, on a tubular member of constant circumference, produce a uniform tension.

Since the permissible elongation without rupture of certain types of fin material, such as certain kinds of com- 'mercially available aluminum stock, is between 1% or 2% of the circumference of inch tubing, or approxi- 'mately .02 to .025 inch, it is necessary to prevent any more than the desired 1% elongation of the fin material (i.e. .012 inch for inch tube stock) during wrapping to eliminate continual breaking of the fin material at some point between the forming means and the tubing.

However, commercially available copper tubing of inch diameter has a plus or minus two thousandths of an inch variation in diameter, and this alone provides a variation of .012 inch in the circumference of the tubing. As stated previously, the tin material that is being presented to the tubing is already maintained at a particular elongation or tension such as the .012. inch mentioned above for aluminum fin material, and, if the tubing runs at its maximum circumference for a short period, the additional elongation of the material soon causes the material to exceed the permissible limit of elongation This is espeanemone 9 t a plurality of separate fin sections by slitting the material'from one edge to the narrow base flange or-hem. The slitting of the fin stock transversely to its length makes it more likely to tear, thus further reducingthe permissible elongation .of the strip material.

In order to permit a reasonable tension in .the material during wrapping it is necessary, therefore, to main"- tain the tubing at a very close diameter or circumference. This, of course, is accomplished 'by the swaging assembly 29. -In a tested embodiment of the present invention, the swaging rolls 29a, 29b and 290 reduce, for example, a We inch tubing having an average circumference of 1.178 inches to a tubing having a circumference-of1.168 inches plus or minus .002 inch. This is only .004inch variation on the circumference of tubing. When fin material is fed at the rate of 1.168 inches less 1% (.012) or at aproximately 1.156 inches for each revolutionof the head, there is little danger of exceedingnthe maximum permissible elongation of the material even though the tubing might run at its maximum diameter of L170 inches for a long period. For greater diameters .of tubing and for dilferent materials of fin stock the permissible amount of elongation of the fin material for each wrap thereof onto the tubing may change. However, in' all. cases, it is first desirable to reduce th'ecircumference of thetubing to some constant and uniform size so that the strip stock may be maintained at a uniform tension while being wrapped onto the tubing.

A further and important function of the. swaging rolls 29, in addition to reducing the circumference oflthe tubular member 3, is to make the member more perfectly round. Tubing when wrapped into rolls takes on the configuration shown in exaggeratedcross section in FIG. 15. That is, whenever tubing is wrapped in rolls or bent, it flattens out into a somewhat elliptical shape. Inthis form it has a major diameter x and a minor diameter y and, if wrapped in this form, it causes a very uneven type of wrapping. For each revolution of the head the elliptical cross section of such tubing causes two pulses which are the result of slight changes in tension produced in the fin material due to the change in shape of the tubing. These pulses are sufficient at times to cause the fin material to rupture. Since it is more expedient to ship large quantities of tubing in roll form, the elliptical shape produced in the tubing is always present. in most commercially available tubing and the swaging rolls correct it.

Operation of the present machine is relatively simple and is very efiicient in that great lengths of tubing are passed through the machine while .fin material is continuously wrapped thereon. When the supply of fin ma terial is exhausted, a new coil of fin material. is loaded onto the rotatable support table 42 and clamped into place. The end of the material is passed through the forming means and a few turns of material are wrapped around the tubing and held thereon by the adhesive on the tubing. The wrapping operation then begins again. In order to supply suffic-ient strip material for a long length of tubing it is contemplated that the tube, upon being wrapped, will proceed upwardly and axially through several coils of stored. strip stock 41. Upon exhausting of one coil of strip stock, another is lowered onto the table and the tube need not be severed to permit the insertion of additional coils of fin stock 41.

By the present invention there has been provided a machine for continuously wrapping long lengths of tubing with a serrated fin material having discontinuous .fin sections. The machine is designed such that the tubing is passed through the machine axially without rotation while the wrapping and forming components of the machine are rotated around the tubular material. Moreover, the machine includes an arrangement for maintaining a uniform and precalculatedtension in the. fin material during wrapping which arrangement requires. no translationally movable parts between the forming means and the point where the fin material is wrapped onto the tubing.

While in. accordance with the patent statutes there has been, shown and-described what at present is considered to be the, preferredembodiment of the invention, it be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, the aim of the appendedclaims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim is new and desire to secure by Letters Patentof the United States is:

l. A machine for manufacturing finned tubing of the type having a plurality ofindividual fin sections extending outwardly therefrom comprising a rotatable head having anaxially disposed passage therein, means for rotating said head, means, on said head for supporting a coil of strip stock'about said axial passage, said coil supporting means being rotatable with respect to said head, means operated in timed relation with the rotation of said head for reducing the exterior circumference of tubing to a uniform circumference and for advancing said tubing at a governedrate through said axial passage in said rotatable head, forming means on said head for removing strip stock from said coil and forming it into fin material havinga pluralityof individual fin sections connecting at one endto abase flange, means on said head for directing said-fin material onto said tubing being advanced through said head thereby to wrap said fin material onto said tubing as said head is rotated around said tubing with said base flange of saidfinmaterial disposed in flat-Wiseengagement with said tubing and with said individual fin sections extending radially outward therefrom, and means carried by said head for driving said forming means to release a length of fin material for each revolution of said headthat is less than the length demanded for helical wrapping onto the uniform circumference of said tubing I of strip stock about said axial passage, said coil supporting means being rotatable with respect to said head, swagingrolls'through which tubing is passed for reducing the exterior circumference of said tubing to a uniform circumference, feeding rolls operated in timed relation with the rotation of said head for advancing said tubing at a predetermined rate through said axial passage in said head, forming means on said head for removing strip stockfrom said coil and forming it into fin material having a-plurality of indiwidual fin sect-ions connecting at oneend'to a base flange, meanson said head for directingsaid fin material onto said tubing being advanced through'said head thereby to wrap said fin material onto said tubing as said head is rotated about said tubing with-said baseflange of said fin material in flat-wise engagement on said tubing and with said individual fin sections extending radially outward therefrom, and means carried by said head for driving said forming means to release a length of fin material for each revolution of said 'head that is less than the length demanded for helical wrapping upon the uniform circumference of said tubing being advanced through said axial passage by an amount within'the permissible limit of elongation of said "fin material for each wrap thereof onto said tubing so .that a predetermined tension is continuously maintained 'insaid fin material.

3. A machine for manufacturing finned tubing of the typehaving a plurality of individual fin sections extending outwardly therefrom comprising a base, a rotatable head mounted for rotation above said base and having an axially disposed passage therein, means for rotating said head, a tubular guide aflixed to said base and extending into said axial passage in said rotatable head, means on said head for supporting a coil of strip stock about said axial passage, said co-il supporting means being rotatable with respect to said head, a plurality of swaging rolls operated in timed relation with the rotation of said head for engaging tubing around the circumference thereof and for reducing the exterior circumference of said tubing to a uniform circumference, a plurality of feed rollsoperated in timed relation with the rotation of said head and arranged between said swaging rolls and said tubular guide for directing said tubing into said tubular guide and for advancing said tubing at a governed rate therethrough, forming and slitting rolls on said head for removing strip stock from said coil and for forming it into fin material having a plurality of individual fin sections connecting at one end to a base flange, means on said head for directing said fin material onto said tubing being advanced through said tubular guide into said head thereby to wrap said fin material onto said tubing as said head is rotated about said tubing with said base flange of said fin material in flat-wise engagement upon said tubing and with said individual fin sections extending radially outward therefrom, and means carried by said head for driving said forming and slitting rolls to supply fin material at a linear rate for each revolution of said head that is approximately 1% less than is demanded by the uniform circumference of said tubing as it is advanced at a governed rate through said axial passage so that a predetermined tension is maintained in said fin material.

4. A machine for manufacturing finned tubing of the type having a plurality of individual fin sections extending outwardly therefrom comprising a rotatable head having an axially disposed passage therein, means for rotating said head, means on said head for supporting a coil of strip stock about said axial passage, said coil supporting means being rotatable with respect to said head, means operated in timed relation with the rotation of said head for reducing the exterior circumference of tubing to a uniform circumference and for feeding said tubing through said axial passage in said rotatable head, forming rolls on said head for removing said strip stock from said coil and for forming a base flange thereon, slitting rolls on said head for slitting said strip stock transversely from one end thereof to form a plurality of individual fin sections connecting at one end with said base flange, means on said head for directing said fin material onto said tubing being advanced through said head thereby to wrap said fin material onto said tubing as said head is rotated about said tubing, with said base flange of said fin material in flat-wise engagement upon said tubing and with said individual fin sections extending radially outward therefrom, and means carried by said head for driving said forming rolls and said slitting rolls to supply fin material at a linear rate for each revolution of said head that is less than is demanded for helically wrapping said fin material onto the uniform circumference of said tubing as it is advanced through said axial passage by an amount within the permissible limit of elongation of said fin material for each wrap thereof onto said tubing so that a predetermined tension is continuously maintained in said fin material.

5. A machine for manufacturing a finned tubing of the type having a plurality of individual fin sections extending outwardly therefrom comprising a rotatable head having an axially disposed passage therein, means for rotating said head, means on said head for supporting a coil of strip stock about said axial passage, said coil supporting means being rotatable with respect to said head, means operated in timed relation with the rotation ofsaid head for reducing the exterior circumference of tubing to a uniform circumference and for feeding said tubing at 'a governed rate through said axial passage in said rotatable head, base flange forming means upon said head for removing said strip stock from said coil and for forming a base flange thereon, said base flange forming means including upper and lower forming rolls for engaging said strip stock along its major width with one edge of said stock extended outwardly of said upper and lower forming rolls, a cone-faced roll for engaging said outwardly extending edge of said stock and rolling it into confinement against the side face of said upper roll thereby forming a right anglebase flange thereon, slitting rolls on said head for slitting said strip stock transversely from one end to a point adjacent said base flange toform individual fin sections connected at one end to said base flange, means on said head for directing said fin material onto said tubing being advanced through said head thereby to wrap said fin material onto said tubing as said head is rotated about said tubing with said base flange of said fin, material in flat-wise engagement upon said tubing and with said individual fin sections extending radially outward therefrom, and means carried by said head for rotatably driving said forming rolls and said slitting rolls to release fin material at a linear rate for each revolution of said head that is approximately 1% less than is demanded for helically wrapping said fin material onto the uniform circumference of said tubing as it is advanced at a governed rate through said axial passage so that a predetermined tension is continuously maintained in said fin material.

6. A machine for manufacturing a finned tubing of the type having a plurality of individual fin sections extending radially outward therefrom, comprising a rotatable head having an axially disposed passage therein, means for rotating said head, a tubular guide having one end extending into said axial passage in said head through which tubing is advanced into said rotatable head, means on said head for supporting a coil of strip stock about said axial passage through which'said tubing is advanced, said coil supporting means being rotatable with respect to said head, swagin-g rolls disposed below said tubular guide for engaging said tubing and reducing the exterior circumference of said tubing to a uniform circumference, a plurality of feed rolls arranged between said swaging rolls and said tubular guide, means for driving said swag-ing and feed rolls in timed relation with the rotation of said head thereby to advance tubing at a predetermined rate through said tubular guide, base flange forming means upon said head for removing strip stock from said coil and for forming a base flange thereon, said base flange forming means including upper and lower forming rolls for engaging said strip stock along its major width with one edge of said stock extended outwardly of said uppm and lower forming rolls, a cone-faced roll for engaging said outwardly extending edge of said stock and roiling it into confinement against the side face of one of said rolls to form a right angled base flange thereon, slitting rolls on said head for slitting said strip stock transversely from one edge to a point adjacent said base flange to form individual fin sections connecting at one end with said base flange, means on said head for helically wrapping said fin material onto said tubing being advanced through said head with said base flange in flat-wise engagement upon said tubing and with said individual fin sections extending radially outward therefrom as said head is rotated about said tubing, and means carried by said head for rotatably driving said forming rolls and said slitting rolls to supply fin material at a linear rate for each revolution of said head that is approximately 1% less than is demanded for helically wrapping said fin material onto the uniform circumference of said tubing as said tubing is advanced through said axial passage so that a predetermined tension is maintained in said fin material. I

7. A machine for manufacturing finned tubing of'the type having a plurality of individual fin sections extending outwardly therefrom comprising a base, a hollow rotatable spindle supported above said base for rotation about a vertical axis, a rotatable head on the upper end of said spindle, said rotatable head having an axially disposed passage therein, means for rotating said spindle md thereby said rotatable head, a tubular guide extending upwardly through said rotatable spindle into said axial passage in said rotatable head, said tubular guide being stationary with respect to said spindle and rotatable head, means on said head for supporting a coil of strip stock about said axial passage, said coil supporting means being rotatable with respect to said head, swaging rolls within said base for engaging tubing and for reducing the exterior circumference of said tubing to a uniform circumference, a plurality of feed rolls arranged between said swaging rolls and said tubular guide for advancing said tubing at a governed rate through said tubular guide and said axial passage, gearing means operated in timed relation with the rotation of said spindle and said head for driving said swaging rolls and feed rolls to advance tubing upwardly through said tubular guide at a predetermined linear rate, forming and slitting rolls on said head for removing strip stock from said coil and forming it into fin material including a plurality of individual fin sections connecting at one end to a base flange, means on said head for directing said fin material onto said tubing being advanced through said head thereby to Wrap said fin material onto said tubing as said head is rotated around said tubing with said base flange of said fin material in flat- Wise engagement on said tubing and with said individual fin sections extending radially outward therefrom, and means carried by said head for driving said forming and slitting rolls to release fin material for each revolution of said head at a linear rate that is approximately 1% less than is demanded for helically wrapping said fin material onto the uniform circumference of said tubing as it is advanced at a governed rate through said axial passage so that a predetermined tension is continuously maintained in said fin material.

8. A machine for manufacturing finned tubing of the type having a plurality of individual fin sections extending outwardly therefrom comprising a rotatable head having an axially disposed passage therein, means for rotating said head, means on said head for supporting a coil of strip stock about said axial passage, said coil supporting means being rotatable with respect to said head, means operated in timed relation with the rotation of said head for reducing the exterior circumference of tubing to a uniform circumference and for advancing said tubing at a governed rate through said axial passage in said rotatable head, forming rolls on said rotatable head for removing strip stock from said coil and for forming a base flange thereon, upper and lower slitting rolls on said head for slitting strip stock transversely from one end to a point adjacent said base flange to form a plurality of individual fin sections connecting at one end with said base flange, means on said rotatable head for guiding said fin material onto said tubing being advanced through said head thereby to wrap said fin material onto said tubing as said head is rotated about said tubing with said base flange of said fin material in flat-wise engagement on said tubing and with said individual fin sections extending radially outward therefrom, and means carried on said head and operated in timed relation with the rotation of said head for driving at least one of said slitting rolls to release fin material at a linear rate for each revolution of said head that is approximately 1% less than is demanded for helioally wrapping said fin material onto the uniform circumference of said tubing as it is advanced at a governed rate through said axial passage so that a predetermined wrapping tension is maintained in said fin material.

9. A machine for manufacturing finned tubing of the type having a plurality of individual fin sections extending radially outward therefrom, comprising a base, a hollow spindle supported by said base for rotation about a vertical axis, a tubular guide fixedly secured to said base and extending upwardly through said rotatable spindle, a rotatable head carried by said spindle and having an axially disposed passage into which said tubular guide extends, means for rotating said spindle and thereby said rotatable head, means on said head for supporting a coil of strip stock about said axial passage, said coil supporting means being rotatable with respect to said rotatable head, a plurality of swaging rolls in said base below said tubular guide, means for driving said swaging rolls in timed relation with the rotation of said spindle for reducing the exterior circumference of tubing to a uniform circumference and for advancing said tubing upwardly at a governed rate through said tubular guide into said rotatable head, base flange forming means on said rotatable head for removing strip stock from said coil and for forming a base flange thereon, said base flange forming means including upper and lower forming rolls for engaging said strip stock along its major width with one edge of said stock extending outwardly of said upper and lower forming rolls, a cone-faced roll for engaging said outwardly extending edge of said stock and rolling said edge into confinement against the side face of said upper roll to form a right angled base flange on said strip stock,

slitting rolls mounted on said head for slitting said strip stock transversely from one end to a point adjacent said base flange to form a plurality of individual fin sections connecting at one end with said base flange, a sun gear around the outer periphery of said tubular guide adjacent said rotatable head, means on said rotatable head for guiding said fin material onto said tubing being advanced through said head thereby to wrap said fin material onto said tubing as said head is rotated about said tubing with said base flange of said fin material in flat-wise engagement on said tubing and said individual fin sections extending radially outward therefrom, and a gear train driven by the rotation of said rotatable head about said sun gear for rotatably driving said forming rolls and said slitting rolls to supply fin material at a linear rate for each revolution of said head that is approximately 1% less than is demanded for helically wrapping said fin material onto the uniform circumference of said tubing as said tubing is advanced into said rotatable head so that a predetermined tension is maintained in said fin material.

10. A machine for manufacturing finnedtubing of the type having a plurality of individual fin sections extending outwardly therefrom comprising a rotatable head having an axially disposed passage therein, means for rotating said head, a coil support table on said head for supporting a coil of strip stock about said axial passage, said coil support table being rotatable with respect to said head, means operated in timed relation with the rotation of said head for reducing the exterior circumference of tubing to a uniform circumference and for advancing said tubing at a governed rate through an axial passage in said rotatable head, forming and slitting rolls on said head for removing strip stock from said coil and forming it into fin material including a plurality of individual fin sections connecting at one end to a base flange, means on said head for directing said fin material onto said tubing being advanced through said head thereby to wrap said fin material onto said tubing as said head is rotated about said tubing with said base flange of said fin material in flat-wise engagement on said tubing and with said fin sections extending radially outward therefrom, means carried by said head for driving said forming and slitting rolls to release fin material at a linear rate for each revolution of said head that is approximately 1% less than is demanded for helically wrapping said fin material onto the uniform circumference of said tubing as said tubing is advanced through said axial passage so that a predetermined tension is maintained in said fin material and brake means between said support table and said rotatable head '15 .for retarding the rotation of said support table with respect to said rotatable head thereby to maintain a predetermined tension in said strip stock as it is fed from said coil on said table to said fin forming means.

11. A machine for manufacturing finned tubing of the type having a plurality of individual fin sections extending outwardly therefrom comprising a base, a hollow spindle supported on said base for vertical rotation thereon, a rotatable head carried by said spindle and having an axially disposed passage therein, means for rotating said spindle and thereby said head, a support table mounted on rollers above said rotatable head for permitting the rotation of said table with respect to said head, said table supporting a coil of strip stock about said axial passage in said head, means operated in timed relation with the rotation of said head for reducing the exterior circumference of tubing to a uniform circumference and for advancing said tubing at a governed rate through said axial passage in said rotatable head, fin forming means on said head for removing strip stock from said coil and for forming it into fin material including a plurality of individual fin sections connecting at one end to a base flange, a plurality of brake means arranged in an archimedes spiral around said coil support table, each of said brake means having a friction shoe engaging the upper surface of said rotatable head, plunger means associated with each of said brake means for forcing said friction shoe into engagement'with said rotatable head when strip stock is carried on said table above each of said brake means, said brake means retarding the rotation of said table with respect to said head thereby to provide a predetermined tension in said strip stock when said strip stock is fed from said coil, each of said brake means releasing its brake shoe as the radius of said strip stock decreases sufficiently to provide clearance above said plunger means thereby to gradually decrease the amount of force required to rotate said table with respect to said head, means on said head for directing said fin material onto said tubing being advanced through said head thereby to wrap said fin material onto said tubing as said head is rotated around said tubing with said base flange of said fin material in flat-wise engagement on said tubing and with said fin sections extending radially outward therefrom, means carried on said head for driving said fin forming means to release fin material at a linear rate for each revolution of said head that is approximately 1% less than is demanded for helically wrapping said fin material onto the uniform circumference of said tubing as said tubing is advanced through said axial passage so that a predetermined tension is continuously maintained in said fin material.

12. A machine for manufacturing finned tubing of the type having a plurality of individual fin sections extending outwardly therefrom comprising a rotatable head having an axially disposedpassage through which tubing is advanced, means for rotating said head, means on said head for supporting a coil of strip stock about said axial passage through which said tubing is advanced, said means including a horizontal support table supported on rollers above said head, an overrunning brake means for preventing overrunning of said table with respect to said rotatable head as the speed of rotation of said head is reduced, said overrunning brake meansincluding a circular flange extending downwardly from the bottom of said coil support table, a friction responsive wedging mechanism mounted on saidrotatable head and engaging said downwardly extending flange, said friction responsive wedging mechanism permitting slow rotation of said table in one direction with respect to said head to permit normal feed off of strip stock from said coil While preventing rotation of said table in the other direction with respect to said head by wedging against said downwardly extending flange, means operated in timed relation with'the rotation of said head for reducing the exterior circumference of tubing to a uniform circumference and for advancing said tubing at a governed rate through said axial passage in said rotatable head, fin forming means for removing strip stock from said coil and forming it into fin material including a plurality of individual fin sections connecting at one end to base flange, and means carried on said head for driving said fin forming means to release fin material at a linear rate for each revolution of said head that is approximately 1% less than is demanded for helically wrapping said fin material onto the uniform circumference of said tubing as said tubing is advanced through said axial passage so that a predetermined tension is maintained in said fin material.

13. A machine for manufacturing finned tubing of the type having a plurality of individual fin sections extending outwardly therefrom comprising a base, a rotatable head mounted for rotation above said base and having an axially disposed passage therein, means for rotating said head, a tubular guide aflixed to said base and extending into said axial passage in said rotatable head, means on said head for supporting a coil of strip stock about said axial passage, said coil supporting means being rotatable with respect to said head, a plurality of swaging rolls for engaging tubing around the circumference thereof and for reducing the exterior circumference of said tubing to a uniform circumference, a plurality of feed rolls arranged between said swaging rolls and said tubular guide for directing said tubing into said tubular guide and for advancing said tubing at a predetermined rate therethrough, said swaging and feed rolls being operated in timed relation with the rotation of said head, fin forming means on said head for removing strip stock from said coil and for forming it into fin material having a plurality of individual fin sections connecting at one end to a base flange, means on said head for driving said fin forming means to supply fin material at a linear rate for each revolution of said head that is approximately 1% less than is demanded for helically wrapping said fin material onto the uniform circumference of said tubing as it is advanced through said tubular guide into said axial passage, a fin straightening head mounted on the end of said tubular guide, said fin straightening head having an inclined surface adjacent which said fin material is wrapped onto said tubing with said base flange in flat-Wise engagement upon said tubing and with said individual fin sections extending radially outward therefrom as said head is rotated about said tubing and a straightening roll carried on said head, said straightening roll having a surface cooperating with said inclined surface on said fin straightening head for straightening said individual fin sections as said fin material is directed onto said tubing. 7

14. In a machine for manufacturing finned tubing of the type having a plurality of individual fin sections extending outwardly therefrom comprising a base, a hollow spindle mounted above said base for vertical rotation thereon, a rotatable head carried on the end of said hollow vertical spindle, said rotatable head having an axial passage therein, means for rotating said spindle and thereby said head, a tubular guide affixed to said base and extending axially upward through said hollow spindle into said axial passage in said rotatable head, means in said base operated in timed relation with the rotation of said head for reducing the exterior circumference of tubing to a uniform circumference and for advancing said tubing upwardly at a governed linear rate through said tubular guide into said rotatable head, means on said head for supporting a coil of strip stock about said axial passage through which said tubing is advanced, said coil supporting means being rotatable with respect to said head, forming means upon said head for removing strip stock from said coil and for forming a base flange thereon, said base flange forming means including upper and lower forming rolls for engaging said strip stock along its major width with one edge of said stock extending outwardly of said upper and lower forming rolls, a cone-faced roll for engaging said outwardly extending edge of said stock and rolling it into confinement against the side face of said upper roll thereby forming a base flange thereon, slitting means on said head for slitting said strip stock transversely from one edge to a point adjacent said base flange to form individual fin sections connected at one end to said base flange, means carried by said head for rotatably driving said forming rolls and said slitting rolls in timed relation with the rotation of said head to release fin material for each revolution of said head that is approximately 1% less than is demanded for helically wrapping said fin mateii-al onto the uniform circumference of said tubing as said tubing is advanced through said tubular guide into said rotating head, -a fin straightening head mounted on the end of said tubular guide, said fin straightening head having an inclined surface adjacent which said fin material is Wrapped onto said tubing with said base flange in flat-wise engagement with said tubing, a straightening roll carried on said head and rotatable therewith, said straightening T0111 cooperating with said inclined surface on said fin straightening head for engaging opposite sides of each of said individual fin sections and straightening said sections as said fin material is wrapped onto said tubing and means carried by said head for rotatably driving said straightening roll in timed relation with the rotation of said head.

15. In a machine for manufacturing finned tubing of the type having a plurality of individual fin sections extending outwardly therefrom comprising a rotatable head having an axially disposed passage therein, means for rotating said head, means on said head for supporting a coil of strip stock about said axial passage, said coil supporting means being rotatable with respect to said head, means operated in timed relation with the rotation of said head for reducing the exterior circumference of tubing to a uniform circumference and for advancing said tubing through said axial passage in said rotatable head, base flange forming means on said head for removing said strip stock from said coil and for forming a base flange thereon, slitting rolls on said head for slitting said strip stock transversely from one end thereof to form a plurality of individual fin sections connecting at one end with said base flange, means on said head for directing said fin material onto said tubing being advanced through said head thereby to wrap said fin material onto said tubing as said head is rotated about said tubing with said base flange of said fin material in flat-wise engagement upon said tubing and with said individual fin sections extending radially outward therefrom, and means carried by said head for rotatably driving said slitting rolls in timed relation with trespect to the rotation of said head so that said slitting rolls release a length of fin material for each revolution of said head that is less than is demanded for helically wrapping said fin material onto the uniform circumference of said tubing as said tubing is advanced through said axial passage in said rotatable head by an amount within the permissible limit of elongation of said fin material for each wrap thereof onto: said tubing so that a wrapping tension is continuously maintained in said fin material.

References Cited in the file of this patent UNITED STATES PATENTS 336,899 Davis Mar. 2, 1886 1,883,222 VVoOd Oct. 18, 1932 1,960,517 Taylor May 29, 1934 2,167,971 Cadden Aug. 1, 1939 2,199,594 Kent May 7, 1940 2,303,760 Rafter Dec. 1, 1942 2,364,736 McGlone Dec. 12, 1944 2,472,245 Busse June 7, 1949 2,532,239 Newlin Nov. 28, 1950 FOREIGN PATENTS 811,081 France Apr. 6, 1937