US2799389A

US2799389A - Fin winding machines

Info

Publication number: US2799389A
Application number: US464388A
Authority: US
Inventors: Robert M Stikeleather
Original assignee: Aerofin Corp
Current assignee: Air and Liquid Systems Corp
Priority date: 1954-10-25
Filing date: 1954-10-25
Publication date: 1957-07-16
Anticipated expiration: 1974-07-16

Description

July 16, 1957 R. M, STIKELEATHEZR ,7

I FIN WINDING MACHINES Filed Oct. 25, 1954 9 Sheets-Sheet 1 P9 Wk k3 Nm NRN R4 W m? I Q m Nm 3 m M v O H A? a R ab I hh\fl O 9 W Nlm an A H 8 MN o m o Q Q. I 0 0 A .I? .9 .0 I

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FIN WINDING MACHINES 9 Sheets-Sheet 3 Filed Oct. 25, 1954 r y 16, 195 R. M. STIKELEATHER 2,799,389

FIN WINDING MACHINES Filed Oct. 25, 1954 9 Sheets-Sheet 4 x i .Q) N 1 s m o v Q 5 o O V i Pg 152291222302 July 16, 1957 Filed Oct. 25, 1954 R. M. STlKELEATHER FIN WINDING MACHINES 9 Sheets-Sheet 5 July 16, 1957 R. M. STIKELEATHER FIN WINDING MACHINES Filed Oct. 25, 1954 Inveaaio 3*": 17022428 5 by W \7- m 9 Sheets-Sheet 6 July 16, 1957 R. M. STIKELEATHE 2,799,339

' FIN WINDING MACHINES Filed Oct. 25 1954 9 Sheets-Sheet 7 1229.16. //////////////fl/fl/fl/fl/fl////////////// l/l 12 5 88 [as yWJF July 16, 1957 Filed Oct. 25,. 1954 R. M. STIKELEATHER FIN WINDING MACHINES 9 Sheets-Sheet 8 JOE July 16, 1957 R. M. STIKELEATHER 2,799,389

FIN WINDING MACHINES Filed Oct. 25, 1954 9 Sheets-Sheet 9 10b M8 I k I06 I08 lawezaioat' lab we I by W 0.9% fltibflazey United States Patent FIN WINDING MACHINES Robert M. Stikeleather, Holbrook, Mass., assignor to Aerofin Corporation, Syracuse, N. Y., a corporation of New Jersey Application October 25, 1954, Serial No. 464,388 8 Claims. (Cl. 203--75) This invention relates to machines for winding extended surface fins spirally on heat exchange tubes.

This application is a continuation-in-part of my copending application, Serial No. 189,854, which was filed on October 12, 1950, and now Patent No. 2,713,375.

A widely used type of heat exchanger for cooling and heating air and other gases, is a metal tube through which a heat exchange fluid is circulated, having a metal ribbon wound spirally on its external surface. Such ribbons on such tubes are usually referred to as fins.

The machines that have been used heretofore for Winding such fins spirally on tubes have been of two types. One type has used crimping rolls for crimping the inner portions of ribbons for causing them to curl about tubes. Such crimped fins are undesirable for many duties due to the high resistance they ofier to gas flowing between them, and due to the inability to space the adjacent convolutions of the fins closely together. Another disadvantage of crimped fins is that excess metal is used in the crimps. The other type of machine has formed a ribbon into a spiral in a first operation, following which the ribbon is placed on a tube in a second operation, and is then secured to the tube, as by soldering, in a third operation. While this other type of machine has formed smooth fins, the cost of the heat exchangers fabricated thereby has been excessive due to the three separate operations involved, and the care required to maintain the proper fin spacing and tension.

A feature of my invention is that a smooth fin is spirally wound directly upon a tube. The ribbon from which the fin is formed is passed first between a pair of rolls which deform its outer portion so that its outer edge has less thickness than its inner edge. This causes the ribbon to curl about the tube to which it is applied. The deforming of the ribbon causes the fin to have irregularities in its surface, and to remove such irregularities, a plurality of closely spaced circular discs are placed adjacent the tube so that the first and second discs grip the first convolution being formed between their adjacent surfaces; the adjacent surfaces of the second and third discs grip the second convolution of the fin, and the adjacent surfaces of the third and fourth discs grip the third convolution of the fin. More or fewer discs could be used. Preferably, the surfaces of two or more of the discs are escalloped with ridges on the surface of one disc being opposite depressions in the adjacent surface of another disc.

The discs are rotated in the opposite direction to that in which the tube is rotated, and at a much faster rate, and not only iron out irregularities in the fin as it is applied to the tube, but exert pull on the ribbon and thus aid in the rotation of the tube. Spacers having different thicknesses are provided for spacing the discs diflerent distances apart for varying the pull exerted by the discs upon the ribbon.

The conventional firming machine has a head for rotat ing and advancing a tube on which a fin is to he wound, which advances the tube at a fixed rate so that the spacing between the fins wound on the tube is fixed.

ice

Another feature of my invention is that a head is provided for rotating and advancing a tube on which a fin is to be wound, which can easily be adjusted for varying the spacing between the fins.

Another feature of my invention resides in the provision of means easily adjustable by an operator during the fin winding process for varying the speed of rotation of the tube upon which a fin is being wound.

Another feature of my invention resides in providing a ribbon deforming roll having a beveled fin contacting surface which cooperates with the flange of a flanged roll to stretch the outer portion of the ribbon for causing it to curl. The flange of the flanged roll extends between the first and second convolutions of the fin being formed, and since the fin spacing is close, the flange has to be thin.

A flanged roll with a flange having a relatively large diameter is desired for minimizing the differences between the relative rubbing actions which occur on the inner and outer portions of the ribbon. For preventing excessive pressure on the relatively thin flange of the flanged roll, a relatively small beveled roll is used. A relatively large backing-up roll is provided for taking the strain off of the relatively small beveled roll. Prior machines of this same general type used very large deforming rolls capable of withstanding the strains involved, with the result that the flanges of the flanged rolls were so thick that a fin with closely spaced convolutions could not be wound on a tube.

An object of this invention is to wind smooth fin spirally on a tube. 7

Another object of this invention is to vary the spacing between convolutions of a fin wound spirally on a tube.

Another object of this invention is to provide a head for rotating and advancing a tube upon which a fin is to be wound, which can easily be adjusted during the winding of the fin, for varying the spacing of the convolutions of the fin.

Another object of this invention is to provide means for varying the speed of rotation and advance of a tube on which a fin is being wound, during the winding of the fin.

This invention will now be described with reference to the annexed drawings, of which:

Fig. 1 is a plan View looking downwardly upon a fin winding machine embodying this invention;

Fig. 2 is a side elevation of the machine;

Fig. 3 is an end elevation of the machine;

Fig. 4 is a sectional view along the line 4-4 of Fig. 2 with the straightening discs in operating position;

Fig. 5 is a view similar to Fig. 4 except that the straightening discs are pivoted away from operating position;

Fig. 6 is a fragmentary enlarged view in side elevation of the machine with the straightening discs in operating position;

Fig. 7 is a fragmentary, machine;

Fig. 8 is a fragmentary plan view, partially in section, of the machine showing the deforming rolls and one of their drives, and the guides for the ribbon;

Fig. 9 is an enlarged side elevation of the straightening disc assembly;

Fig. 10 is an enlarged side elevation of one of the straightening discs;

Fig. 11 is an enlarged end view of the outer, escalloped portions of the straightening discs;

Fig. 12 is an enlarged section through the outer, escalloped portion of one of the straightening discs;

Fig. 13 is an enlarged plan view with the top plate removed, of the head for rotating and advancing a tube to be finned;

Fig. 14 is a sectional view along the line 144-14 of Fig. 13 with top plate on;

enlarged plan view of the Fig. is a sectional view along the line 1515 of Fig. 13 with the head rotated through an angle of 90;

Fig. 16 is an enlarged sectional view along the line 16l6 of Fig. 13; 7

Fig. 17 is a side section of the auxiliary tuberotating assembly;

Fig. 18 is a side elevation of the assembly of Fig. 17;

Fig. 19 is an enlarged sectional view along the line 1919 of Fig. 17;

Fig. 20 is an enlarged sectional view along the line 20-20 of Fig. 17, and

Fig. 21 is an enlarged fractional view, partially in section, showing one side of the upper portion of the ribbon deforming assembly in its relation to a tube on which a fin is being wound, and showing the lower'portions of the straightening discs between adjacent convol-utions of the fin.

The finning machine illustrated by the drawings has a pair. of end base members 25 which support a vertically extending plate 26 to which the mechanism of the machine is.secured. Supported upon structural angles 22 which are bolted to the upper portion of the right side (facing Fig. 2) of the plate 26 is a housing 27 for a head 28 which rotates and advances a tube 81, and for the assembly of the auxiliary rolls 29 which are provided for aiding in the rotation of the tube. Bolted to the upper portion of the left side of the plate 26 is a housing 30 which contains the ribbon deforming rolls 31 and 32, a shaft 33 and sprocket 34 for driving the roll 32, and a roll 35 which backs-up the roll 31.

A shaft 36 for rotating the head 28 and the rolls 29 has a pulley attached thereto which is driven through a belt 37 and a pulley 39 which is part of a variable speed drive pulley 38. The latter is driven through a belt from a gear box 40.

45. An idler pulley 75 is provided for the belt 46.

The shaft 36 also has attached thereto a pulley 47 which drives through a belt 48, a pulley 49, a shaft 50, a pulley 51 and a belt 52, a pulley 53 which is part of a variable speed drive pulley 54. The latter drives through a belt 55, pulley 56, a hollow shaft 57 to which is attached, within the head 28, a gear 58. An idler pulley 73 is provided for the belt 52.

The shaft 41 also has a pulley 60 thereon which drives through a belt 61 and pulley 62, gearing within the speed reducing gear box 63, the outlet gear 64 of which drives a sprocket 65 which drives through a chain 66 the sprocket 34 on the shaft 33 of the deforming roll 32. An idler pulley 19 is provided for the belt 61.

The gear box drives a vertically extending shaft 67 which is connected through a sleeve 68 to a vertically extending shaft 73 on the upper end of which the defor ing roll 31 is positioned. As previously described, the gear box 40 is driven by the electric motor 45.

A pulley 69 driven from the gear box 63 drives through a belt 70 and pulley 71, a shaft 72 on which are assembled the straightening discs 74.

As shown best by Fig. 21, the deforming roll 31 has a beveled surface which cooperates with the plane surface of the deforming roll 32 to deform the outer portion of a ribbon 80, thereby stretching and lengthening the outer portion of the ribbon and causing it to curl about the tube 81.

It is important that the flange of the flanged roll 32 be thin in order that it can extend between closely spaced fins. This so reduces the strength of the flange that the beveled roll 31 must have a very small diameter so that it has a relatively small surface pressing the ribbon against the thin flange. This, in turn, results in the beveled roll having insufiicient strength so that the backing-up roll 35 is provided for taking the strain off of the small beveled roll.

Guide plates 82 guide the ribbon between the

rolls

31 and 32 as best illustrated by Figs. 1, 6 and 7, the ribbon being reeled off of a conventional reel which is not shown. A cover plate 20 extends over the inner portions of the guides 82.

The discs 74 which straighten out irregularities in the fin as it is wound on the tube 8.1, are preferably escalloped as shown by Figs. 91 1, with the ridges on the surface of one disc facing depressions in the adjacent surface of the adjacent disc. The discs are clamped onto the shaft 72 between clamping plates 85, the outer of which is tightened against the discs by a nut 86 on the threaded end of the shaft 72. The discs 74 have the washers 87 therebetween. Washers of different thicknesses are provided for varying the spacing between the discs for causing them to exert different pressures on a fin having convoluti-ons gripped between the discs. The spacing can be adjusted so closely that the discs will grip the fin sufficiently to rotate the tube 81. The discs 74 and washers 87 have similar circular openings for receiving a liningup screw 89.

The disc assembly is pivoted to the machine frame whereby the discs can be rotated bodily away from the tube 81 for providing access to the deforming rolls at the start of an operation. The shaft 72 is journalled in a circular member 90 which is screwed into a member 91 which is pivoted about a shaft 92 which is held in the lower end of a member 93 which is attached to the frame of the machine. The disc assembly has a handle 94 which is pivoted about a pivot rod 95 to the member 93, and is pivoted about a rod 96 to one end of a link 97, the other end of which is pivoted about a rod 98 to the member 91.

Movement of the handle 94 outwardly causes the disc assembly to swing upwardly and outwardly away from its operating position shown by Fig. 4 to the position shown by Fig. 5.

The discs 74 are rotated in a direction opposite to which the tube 81 is rotated, at a speed substantially higher than the speed at which the tube is rotated, for maintaining tension in the fin in the direction in which it is wound on the tube, and for ironing out irregularities formed in the fin as it is wound on the tube. The discs can be adjusted longitudinally of the tube 81 by the screwing of the member 90 further into or out of the member 91.

The shaft 36 which rotates the head 28 and the auxiliary turning rolls 29, is journalled in a ball bearing 76 which is supported in the left side of the housing 27, and has an enlarged portion 101 which is journalled in a ball bearing 102 which is supported in an outer wall 103 of the housing 27. The enlarged shaft portion has, between the

bearings

76 and 102, four equally spaced slots 104 within which are placed auxiliary turning rolls 29 which are rotatably supported on ball bearings 105 in the right ends of levers 106 which are pivoted intermediate their ends on pivot rods 107. The inner portions of the left sides of the levers 106 have circular recesses therein in which are held the coiled springs 108 which contact flattened inner portions 109 of the shaft 36, and press the left ends of the levers 106 outwardly causing their right ends to move inwardly about the rods 107 and to press the rolls 29 against the tube 81. The rolls 29 have grooved serrated tube contacting surfaces so that they clamp the tube therebetween and cause it to rotate when the shaft 36 is rotated. The rolls 29 rotate about the ball bearings 105 when the tube 81 is advanced by advancing

rolls

118 and 119.

The right end of the enlarged portion 101 of the shaft 36 has a flange 100 to which is secured by bolts 111, the head 28 which advances the tube 81 through the machine and aids the rolls 29 to rotate the tube while it is being advanced. The head 28 has the

counter-weights

112 and 113 pivoted thereto about the

pivot rods

114 and 115 respectively, which are secured to the head 28. Tube adand 117 respectively,

vancing rolls 118 and 119 are attached to shafts 116 which are journalled in the outer ends of the

counter-weights

112 and 113 respectively. The

rolls

118 and 119 have grooved serrated edges where they contact the tube 81.

Worm wheels

120 and 121 are also secured to the

shafts

116 and 117 respectively. The latter have threaded ends on which are secured

nuts

124 and 125 respectively, and lock

nuts

126 and 127 respectively.

The worm wheel 120 is meshed with a worm 127 (Fig. 16) which is formed on a rotary shaft 128 which is journalled in the outer end of the head 28. The outer end of the-shaft 128 has a gear 129 secured thereto, and which is meshed with a single spur gear 58 on the shaft 57.

The worm wheel 121 is meshed with a worm 127' similar to the worm 127, which is formed on a rotary shaft 130 similar to the shaft 128, and to the outer end of which is attached a gear 131 which also is meshed with the gear 58.

The counter-weight 112 has a plunger 133 within a bore at its inner end which contacts the flange 100 and which is urged by the coiled spring 134, under the pressure of a screw 135 threaded into the bore, against the flange 100. The counter-weight 113 has a plunger 166 within a bore at its inner end which contacts the flange 100, and which is urged by a spring 167 under the pressure of a screw 168 threaded into its associated bore, against the flange 100. The

screws

135 and 138 can be screwed towards the flange 100 for increasing the pressure of the

rolls

118 and 119 against the tube 81.

The counter-weights have substantially equal masses on both sides of their pivot rods so that the centrifugal force tending to cause the

rolls

118 and 119 which are to one side of the pivot rods, to move outwardly, is balanced by the centrifugal force tending to cause the portions of the counter-weights on the opposite side of the pivot rods, to move outwardly.

The head 28 is rotated by the shaft 36 which is connected through the flange 100 to the inner side of the head. The

rolls

118 and 119 which grip the tube 81 therebetween are rotated about the axis of the tube by the rotation of the head, and rotate the tube. The rotation of the head also causes the

gears

129 and 131 which are meshed with the gear 58 to rotate around the latter, and to rotate about their axes at a speed depending upon the speed of rotation of the gear 58.

The shaft 36 has a central opening for the passage of a tube 81 through the housing 27 between the rolls 29. The shaft 57, the spur gear 58 and the head 28 have central openings aligned with the central opening in the shaft 36 for the passage of the tube.

Rotation of the

gears

129 and 131 causes rotation of the shafts 128 and 130 respectively, causing the

worm wheels

120 and 121 which are meshed with the worms formed on such shafts, to rotate. This causes the'rolls 118 and 119 which are on the same shafts as the

worm wheels

120 and 121 respectively, to rotate in a direction to move the tube 81 forwardly through the machine. The

worm wheels

120 and 121 are moved slightly away from the worms with which they mesh, when the

rolls

118 and 119 are moved outwardly by an increase in the diameter of a tube 81 being handled, but experience has shown that the variations in tube diameter are only from five to ten-thousandths of an inch so that the meshing is not affected to any appreciable extent. When tubes having different diameters are handled, correspondingly different sized rolls are provided.

From the foregoing it is seen that the speed of rotation of the tube 81 is determined by the speed of rotation of the shaft 36, while the rate at which the tube is advanced is determined independently of the speed of rotation of the shaft 36, and is determined by the speed of rotation of the shaft 57.

The speed of rotation of the gear 58 can be varied for varying the rate at which the tube is independently of its speed of rotation, for varying the spacing between adjacent convolutions of the fin. The variable speed device includes a variable speed pulley 54 shown most clearly by Figs. 2 and 3, which is rotatably mounted on a shaft which is attached to the levers 136 intermediate their'ends. The levers 136 are pivoted at corresponding ends about a pivot rod 137 which is attached to the frame of the machine, and are connected at their other ends to a bar 138 to which is attached the lower end of a rod 139. The upper end of the rod 139 which passes through a bar 140 which is bolted to the frame of the machine, is threaded into the bar 140, and has attached to its upper end a rotary hand-wheel 141. Rotation of the hand-wheel 141 in a clockwise direction causes the rod 139 and the levers 136 to move downwardly and to decrease the speed at which the pulley 56 is driven by the belt 55. This causes the gear 58 to rotate at a slower speed, which, in turn, causes the

gears

129 and 131 torotate at a faster rate resulting in the tube 81 being moved forward more rapidly, and in increased spacing between convolutions of the fin.

Rotation of the hand-wheel 141 in a counter-clockwise direction has the opposite effect, causing the gear 58 to rotate at a higher speed, and the tube to advance more slowly, resulting in decreased spacing between convolutions of the fin.

The variable speed drive is a conventional one such as the Speedmaster. manufactured by the Do All Company of Des Plaines, Illinois.

When the spacing between adjacent convolutions of the fin is changed substantially, spacers having the proper thicknesses are placed between the straightening discs 74.

The speed of rotation of the tube rotating rolls 29 and of the head 28 can be adjusted for varying the speed of rotation of the tube 81, by another variable speed drive which includes the

pulleys

38 and 39 which are rotatably mounted on a shaft which is attached to the levers 146 intermediate their ends. The levers 146 are pivoted at corresponding ends about a pivot rod 147 which is attached to the frame of the machine, and are connected at their other ends to a bar 148 to which is attached the lower end of a rod 149. The upper portion of the rod 149 is threaded through the bar 150 which is bolted to the frame of the machine, and has attached to its upper end a hand-wheel 151. Rotation of the hand-wheel 151 in a clock-wise direction causes the rod 149 and lever 146 to move downwardly, and to decrease the speed at which the shaft 36 is rotated by the belt 37. This causes the tube rotating rolls 29 and the head 28 to rotate more slowly and to rotate the tube 81 more slowly.

Rotation of the hand-wheel 151 in a counter-clockwise direction has the opposite effect, causing the tube rotating rolls 29 and the head 28 to rotate faster and to rotate the tube 81 faster.

The variable speed drive including the

pulleys

38 and 39, the levers 146, the rod 147 and the hand-wheel 151 is similar to the one which includes the pulleys 53 and 54, the lever 136, the rod 55 and the hand-wheel 141 described in the foregoing.

Adjustment of the speed of rotation of the tube 81 independently of its movement forwardly while the fin is being wound on the tube is desirable. An experienced operator can note from the appearance of the fin as it emerges from between the deforming rolls and as it is wound on the tube, when the speed of rotation of the tube should be changed. The ribbon is advanced through the deforming rolls independently of the rotation of the tube but synchronized therewith. Experience has shown that due to changes in the thickness or stiffness in the ribbon or the diameter of the tube on which the ribbon is being wound, or for other reasons, it is often necessary to adjust the speed of rotation of the tube at the start of a fin winding operation and at times during the fin winding.

moved forwardly The rolls 155 are rotatably supported from the frame of the machine above and on opposite sides of the tube 81 over the deforming roll 31 and serve to support the tube adjacent where the fin is applied.

The rubber covered rolls 156 are rotatably supported from the frame of the machine, and serve to support the finned tube adjacent where it leaves the machine.

Operation In operation, a tube upon which a fin is to be wound, is fed into the machine from the right, facing Figs. 1 and 2, through the hollow shaft 57 and between the tube advancing and

rotating rolls

118 and 119 and between the tube rotating rolls 29. These rolls are rotated about the tube by rotation of the shaft 36 and cause the tube to rotate. Its speed of rotation can be adjusted by the handwheel 151. As the tube is being rotated, it is advanced forwardly through the machine by rotation of the

rolls

118 and 119 about their axes as a result of the rotation of the

gears

129 and 131 around the gear 58. The rate of advance of the tube can be adjusted by adjustment of the hand-wheel 141 which varies the speed of rotation of the gear 58.

While the tube is being rotated and advanced, the ribbon 80 is fed between the deforming rolls 31 and 32 where it has its outer portion thinned and lengthened so that the ribbon curls closely about and adheres to the tube. The backing-up roll 35 contacts the roll 31 opposite where it deforms the ribbon, and prevents the small roll 31 from springing away from its working position.

The hand-wheel 151 can be adjusted for varying the speed of rotation of the shaft 36 and that of the tube 81 for maintaining proper synchronization between the rate at which the ribbon is fed onto the tube and the rate of rotation of the tube.

As the fin passes from between the deforming rolls 31 and 32 it has irregularities in its outer portion which are undesired for some duties. The straightening discs 74 are provided for ironing out such irregularities. They are rotated at a speed several times faster than the speed of rotation of the tube, in a direction opposite to the direction of the tube.

At the start of a finning operation, for providing access to the deforming rolls 31 and 32 for feeding a ribbon therebetween, the straightening disc assembly is moved by the handle 94 to the position shown by Fig. 5. Then, the disc assembly is returned to its operating position shown by Fig. 4.

The machine illustrated is one which is used for continuous operation in which tubing on which fin is to be wound is fed continuously into the machine, and in which a cutting mechanism is provided at the outlet of the machine for cutting the finned tube to the desired length as it emerges from the machine.

The straightening discs 74 exert considerable pull on the fin on the tube, and aid in rotating the tube. Thus, in the machine illustrated by the drawings, the tube'rotating and advancing

rolls

118 and 119, the tube rotating rolls 29, and the discs 74 all cooperate to rotate the tube.

While one embodiment of the invention has been described for the purpose of illustration, it should be understood that the invention is not limited to the exact apparatus and arrangement of apparatus illustrated, since modifications thereof may be suggested by those skilled in the art, without departure from the essence of the invention.

What is claimed, is:

1. Tube rotating and advancing mechanism comprising a head, means including a first hollow shaft at one end of said mechanism attached to said head for rotating said head, a pair of counter-weights pivoted to said head, tube advancing and rotating rolls on rotary shafts journalled in said counter-weights, worm wheels on said rotary shafts, worm gears on rotary shafts journalled in said head meshed with said worm wheels, spaced apart spur gears attached to said last mentioned rotary shafts, a single spur gear between and meshed with said spaced apart gears, and means including a second hollow shaft at the other end of said mechanism attached to said single spur gear for rotating said single spur gear independently of the rotation of said head, the opening in said second hollow shaft being aligned with the opening in said first hollow shaft, said head and said single spur gear having central openings aligned with said openings in said hollow shafts for the passage of a tube to be advanced and rotated.

2. The invention claimed in claim 1 in which means is provided for adjusting the last mentioned means for varying the speed at which said single gear is rotated.

3. The invention claimed in claim 2 in which means is provided for adjusting the head rotating means for varying the speed at which the head is rotated.

4. The invention claimed in claim 1 in which means is provided for adjusting the head rotating means for varying the speed at which the head is rotated.

5. The invention claimed in claim 1 in which the head has a portion extending in a plane substantially perpendicular to the axis of the head, in which the counterweights have portions extending alongside said head portion, and in which the counter-weights are pivoted to said head between said first mentioned rotary shafts and said head portion, and in which spring means is provided between said head portions and said counter-weight portions for urging said counter-weight portions away from said head portions.

6. Tube rotating and advancing mechanism comprising a hollow shaft having slots therein extending substantially parallel to the axis of said shaft, means for rotating said shaft, tube rotating rolls rotatably supported in said slots, means spring biasing said rolls towards the axis of said shaft, a tube advancing and rotating head attached to said shaft for rotation therewith, said head comprising a pair of counter-weights pivoted thereto, tube advancing and rotating rolls on rotary shafts journalled in said counter-weights, means spring biasing the advancing and rotating rolls towards the axis of said head, worm wheels on said last mentioned shafts, worm gears on rotary shafts journalled in said head meshed with said worm wheels, spaced apart spur gears attached to said last mentioned shafts, a single spur gear between and meshed with said spaced apart gears, and means for rotating said single gear independently of the rotation of said shaft, said head and single gear having central openings aligned with the opening in said hollow shaft.

7. The invention claimed in claim 6 in which means is provided for adjusting said means for rotating said single gear for varying the speed of rotation of said single gear.

8. The invention claimed in claim 7 in which means is provided for adjusting said shaft rotating means for varying the speed of rotation of said shaft.

References Cited in the file of this patent UNITED STATES PATENTS 767,078 Mueller Aug. 9, 1904 791,544 Davenport June 6, 1905 1,301,679 Gammeter Apr. 22, 1919 1,472,719 Horvath Oct. 30, 1923 1,884,203 Pickhard Oct. 25, 1932 1,896,350 Bundy Feb. 7, 1933 2,251,642 Tilley Aug. 5, 1941 2,316,117 Tilley Apr. 6, 1943 2,374,144 Stikeleather Apr. 17, 1945 2,429,201 Connor Oct. 21, 1947 2,538,950 Schryber Jan. 23, 1951