US3309003A - Apparatus for forming spiral tubing from a ribbon of thin material - Google Patents

Description

CRAWFORD APPARATUS FOR FORMING SPIRAL TUBING March 14, 1967 T. J.

FROM A RIBBON OF THIN MATERIAL 5 Sheets-Sheet 1 Filed May 11, 1964 INVENTOR. Thomas J. Crawford A T TORNE V T. J. CRAWFORD APPARATUS FOR FORMING SPIRAL TUBING March 14, 1967 FROM A RIBBON OF THIN MATERIAL 5 Sheets-Sheet 2 Filed May 11, 1964 &m

d m Am a w n O a T r. m C mm a W 1 2w 1 m9 5% v9 w& m w m 3 O i In 1- a TI m MQ ATTORNEY 5 Sheets-Sheet 5 INVENTOR. Thomas J. Crawford ATTORNEY T. J. CRAWFORD APPARATUS FOR FORMING SPIRAL TUBING FROM A RIBBON OF THIN MATERIAL m h .l. S m T a 4 ,%\W/ b. m9

IIA IIIlllllltlll'lllllllllllflulhVFY TIIII'III March 1967 T. J. CRAWFORD 3,309,003

APPARATUS FOR FORMING SPIRAL TUBING FROM A RIBBON OF THIN MATERIAL 5 Sheets-$heet 4 Filed May 11, 1964 INVENTOR.

Thomas J Crawford ATTORNEY March 14, 1967 "r. J CRAWFORD 3,309,003

APPARATUS FOR FORMING SPIRAL TUBING FROM A RIBBON 0F THIN MATERIAL 5 Sheets$heet 5 Filed May 11, 1964 INVENTOR. Thomas J Crawford BY ATTORNEY 3,399,003 APPARATUS FOR FORMHNG SPIRAL TUBING v FROM A RIBBON 9F THIN MATERIAL Thomas J. Crawford, Bainbridge, Ga, assignor to Universal Metal Hose Company, Chicago, 111., a corporation of Delaware I Filed May 11, 1964, Ser. No. 366,442 17 @laims. (Cl. 228-15) This invention relates generally to apparatus for making spiral tubing from a strip or ribbon of sheet material by forming it into a helix and securing the meeting edges of successive wraps of the helix.

The invention relates particularly to apparatus for making thin Wall tubing, in a choice of diameters, from strip or ribbon selected from a variety of materials, widths and thicknesses.

While this invention is broadly applicable to making tubing from metals, and non-metallic materials such as plastics, it relates especially to apparatus for making tubing from a strip or ribbon of very thin metal such as copper or steel in the order of .Olf thick, by forming the ribbon into a helix and securing the meeting edges of successive wraps as by welding.

A primary object of the present invention is the provision of spiral-tubing-formingapparatus having a pair of tubular, counter-rotatable, axially-aligned mandrels, means for guiding and continuously feeding a ribbon of material diagonally onto and around the mandrels in succession, and means intermediate the ends of the mandrels for securing as by welding the meeting edges of successive wraps of ribbon to produce spiral tubing.

A feature of the present invention is that the first mandrel onto which the ribbon is fed rotates in a direction opposite the movement of the ribbon to thereby stabilize progress of the ribbon wraps in a direction lengthwise of the mandrels,

Another feature is that the tubing, after being welded, is carried along the second mandrel which rotates in the direction which the finished tubing rot-ates, the second mandrel having a longer portion in frictional engagement with the ribbon wraps than the first mandrel.

An object of this invention is the provision of an end less, flexible, friction-belt drive for feeding the ribbon along the guide means and then successively about first and second counter-rotating mandrels. 7

Another object is the provision of control means for varying the relative speeds of the counterrotating mandrels to adjust the pressure between meeting edges of successive ribbon wraps 'at the point of welding. -This enables a very precise control over the density and homogeneity of the metal along the welded edges.

Another object is to weld or otherwise secure the meeting edges of successive wraps of the ribbon at a location between the mandrels, for best adjustment ofthe pressure between the edges at the point of welding.

Another object is to provide a pair of'axially aligned, counter-rotating mandrels with space between them and .to perform the welding operation over that space. Another object, ancillary to this, is to wrap the ribbon substantially completely about said space to make it prac- United States Patent Ofiice ti-cally gas tight and to introduce an inert gas through one of the mandrels into the space to facilitate an electric fusion welding operation on the meeting edges.

Another object is to mount the mandrels, respectively, on a pair of tubular, concentric drive shafts which are journaled for rotation relative to a support frame andto one another and to provide means for cooling at least the second mandrel through a cooling medium path which includes a central cooling tube located within the inner one of the drive shafts.

Another object is a mount the ribbon guide meanson Patented Mar. 14, 1967 an auxiliary frame which is pivotable about .an axis extending in a direction to substantially intersect the welding area adjacent the mandrels; thus, the guide means can be pivotally adjusted about that axis to preselect the angle of approach of the ribbon toward the mandrels to enable the use of different width ribbons and different-diameter mandrels.

Anotherobject is to provide ribbon feeding means in the form of a tensioned, endless, flexible, friction belt and means for driving it in an orbital path along the ribbon guide means and following at least the first ribbon wrap about the mandrels for continuously feeding the meeting edges of successive wraps past the welding operation while they are held in perfect cylindrical alignment with one another against the outer surfaces of the mandrels.

Other objects and advantages will be apparent from the following description taken in connection with the drawings in which:

FIGURE 1 is a front elevation of one preferred form of spinal tube making machine made in accordance with the present invention;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a partial, cross-sectional view of FIG. 1 showing the double mandrel construction. about which the spiral wrapped tube is form-ed;

FIG. 4 is an enlarged cross-sectional view of the lefthand end portion of FIG. 3 showing additional details, particularly the water and gas connections and the mandrel drive pulleys;

FIG. 5 is an enlarged cross-sectional view of the righthand end portion of FIG. 3 showing the area between the two mandrels where the metal strip is welded into tub- FIG. 6 is a fragmentary enlarged view of FIG. 5 showing in more detail the area between the mandrels and the paths of gas and cooling water;

FIG. 7 is a transverse cross-sectional view of the machine, taken at the welding position as indicated by line 7-7 in FIG. 5;

FIGS. 8 and 9 are transverse cross-sectional views of FIG. 6 taken along the lines 8-8 and 9-9 respectively;

FIG. 10 is a fragmentary perspective view of the welding area at the mandrel showing particularly the guide and hold-down arrangement for the incoming met'al strip;

FIG. 11 is a partial plan viewof FIG. 1-0 showing the welding juncture where the incoming metal strip becomes spiral-weldedtubing;.and f FIG. 12- isafragmentary view similar .to..FIG. ll showing schematically an alternate form of welding.- The same parts arereferred to by the same reference numbers throughout the figures of the drawings.

Referring now particularly to FIG. 1, of the embodiment of the invention shown. in .the drawings, there -i s a main, mandrel-supporting frame 21 vwhich'includes' a base 22, and an upright end section 23 with a gusset 24 which supports a split tubular. mandrel enclosure 26. At the opposite or exit end of the base is another upright supporting section 27.

An auxiliary. frame 28 is mounted on the main frame for pivotal movement about an upright axisindicated A-A in FIG. 1 and FIG. 7.. The auxiliary frame is made with a turntable bottom plate 29 which rests upon the base 22 and any suitable means, for example bolt means 31, may be employed to hold the auxiliary frame in a preselected adjusted position.

As will be described in more detail, the auxiliary frame 28 carries the ribbon storage reel, the guide for directing the ribbon diagonally onto the mandrels, and the positive feed means for moving the'ribbon over the guide onto the mandrel means.

The mandrel means comprising first and second countor-rotating mandrels, and the supports and driving mechanisms for them, will now be described.

As best shown in FIG. 3, the tubular mandrel encl-osure 26 supported on the main frame is split lengthwise along the top and is formed with a pair of spaced, longitudinal, upstanding flanges 32, 32. These are drawn together by bolts 33 to grip a mandrel support tube 34 and hold itfirmly in place.

Outer and inner drive shafts 36 and 37 respectively for the first and second mandrels will now be described. Refer to FIGS. 3 and 4. The outer drive shaft 36 is a tube journaled by means of bearings 41, 42 within the mandrel support tube 34. That shaft 36 is held against end play by a collar portion 43 and a threaded l-ock nut 44, at opposite ends. At the mandrel end, the outer. drive 36 terminates in an outwardly flared bore 46 within which is held a tapered end portion 47 of the first mandrel 38 as by a coupling ring 48, the latter being threadedly engaged with the end of the outer drive shaft and in abutment with a collar 49 formed on the outside of the first mandrel. 7

At its left-hand end in FIGS. 3 and 4, the outer drive shaft 36 has an extension 51 to which a. pulley 52 is affixed by a key 53 and set screw 55.

The inner drive shaft 37, which carries the second mandrel 39, is likewise in the form of a hollow tube and is journaled for rotation relative to the outer drive shaft 36 by bearings 54, 56 and 57 (see FIGS. 4 and As shown in FIG. 5, bearings 57 are preferably long, thin, needle bearings which are preferred for the restricted space available there.

As best shown in FIG. 4, the inner drive shaft 37 is provided with a power driving sleeve 58 held by a pressed or snug fit on the turned sections 59 and 61 of the inner drive shaft. provided at the inner end of the driving sleeve 58 to back up the bearing 56. A tubular spacer 64 holds the bearings 54 and 56 properly spaced apart, the twobeing held within a bearing retainer sleeve 66. This latter sleeve is provided with an outer knurled flange 67 and is threadedly assembled within the bore 68 of the outer drive shaft 36. A lock nut 69 holds the sleeve 66- in proper longitudinal position. A short bearing retainer sleeve 71 holds the bearing 54 in place and is itself threadedly engaged within the knurled flange 67.

An outer extension 72 of the power driving sleeve 58 is provided with a pulley 73 held in place by a key 74 and set screw 75. The sleeve extension 72 is, in turn, keyed to the inner drive shaft 37 as at 76'and lock nuts 77, 78 are provided to provide end support.

A multiple rota-table coupling, generally designated 79, and best shown at the left-hand portion of FIG. 4, provides entry and exit for cooling liquid and entry for inert gas such as argon which may be used in the welding operation to be described.

The coupling 79 comprises, in this case, a series of interlocking sections 81, 82, 83, 84, 86 and 87 held together by a series of long bolts 88 (only one shown, in FIG. 4). All the sections are bored internally, as shown, to receive the extreme left end portion of the inner drive shaft 37.

Sections 81, 83 and 86, respectively, have transverse ports fitted with the following: a cooling water intake pipe 89; a water outlet pipe 91; and a gas inlet pipe 92.

The outer end portion of the inner drive shaft 37, within the coupling 79, is counter-bored to receive a manifold tube 93 which directs the fluids into the proper passages. As shown in FIG. 4, the right-hand end portion of the manifold tube 93 has a counter bore into which an outer fluid tube 94 is assembled as for instance by a press fit andsilver solder. At the left-hand portion of the manifold tube 93, there is a smaller counter bore within which an inner fluid tube 96 is similarly assembled. At the extreme left-hand end of the manifold tube 93, as seen-in FIG. 4, there is a bushing 95'which'sup- A threaded nut 62 and a spacer 63 are ports the end of the inner fluid tube 96. If preferred, instead of the press fit and silver solder as above mentioned, the tubes 94 and 96 may simply be pressed snugly into place and maintained fluid tight by O-rings 97 and 98. Likewise, the manifold tube 93 may be maintained fluid tight within the drive shaft counter bore by O-rings 99.

Water enters the pipe 89, passes into the cup-shaped end space 101, around the end of inner drive shaft 37 and manifold tube 93 and passes through the bushing into the inner fluid tube 96. The water passes all the way to the end of the inner tube where it exits as shown in FIG. 5 and, as will be described later, returns in the annular space between tubes 94 and 96.

When return water emerges from said annular space, as stated above, it passes into the counter bore '102, through openings 1G3 and 104 in the manifold and drive shaft and thence out of the water exit pipe 91.

Gas, entering the pipe 92, passes into the annular space 106, thence through opening 197, into counter bore 108, and then flows to the right, toward the welding operation, in the annular space 105 between the outside of tube 94 and the inside surface 1090f the inner drive shaft 37. Gaskets 111 provide fluid tight seals between the adjacent sections of the coupling 79 and prevent leakage and short-circuiting of the Water and gas.

The coupling 79 does not itself rotate. It is The inner drive shaft 37 rotates Within it.

The outer ends of the drive shafts 36 and 37 and the mandrels and associated parts will now be described in connection with FIGS. 5 through 9.

The actual working surfaces of the first and second mandrels are cylindrical, are substantially the same diameter, and are indicated by the reference characters 38a and 39a. At its extreme outer end, the first mandrel 38 is counter bored to receive a seal 112 and a retainer 113 (FIG. 6).

The second mandrel 39 comprises in the present case two pieces numbered 114 and 116 held together by set screw means 117. At the outer end, the mandrel section 114 is keyed to the inner shaft 37 as shown at 118 and a pair of end lock nuts 119, 121 hold the assembly together. The end of the inner drive shaft is closed by a threaded pipe plug 122.

As shown in FIG. 6, the inner end portions of the inner and outer fluid tubes 96 and 94 are maintained concentric with the inner drive shaft 37 by means of collars 123 and 124 respectively. O ring seals are'provided in the peripheries of these collars, as shown in FIG. 6.

Cooling water, flowing leftwise along the outside' of tube 96, within the second mandrel 39, follows this path: it exits through a port 126, into an annular chamber 127 which is adjacent and within the welding space 128 on the outside of the second mandrel. Thence around the chamber 127, inward through port 129 and leftwise toward the water outlet pipe 91 through the annular space between concentric tubes 94 and 96.

As shown in FIGS. 6 and 7, the inert gas flow through the annular chamber along the outside of tube 94 exits through a port 131, into an annular chamber 132, through radial ports 133 into the welding space 128.

It will be understood that, for different diameter spiral tubing, the mandrels will be removed and replaced with different diameter mandrels.

The mandrels are driven in opposite directions relative to one another and the speed of either is controllable relative to the other by the portion of the apparatus shown in FIGS. 1, 2, 3 and 4. Pulley 52, which is for the outer drive shaft 36 and the first mandrel 38, is driven by a motor 136, variable speed transmission 137 having a speed control handle 138, belt 139, angle drive 141, and belt 142. By a similar arrangement, pulley 73 for the inner drive shaft 37 and the second mandrel 39 is driven by a motor 143, variable speed transmission 144 controlled by handle 146,'belt 147, angle drive 148,

stationary.

. tubing to be produced. The

and belt 149. The mandrels are rotatably driven in opposite-directions as shown by" the arrows in FIG. 11.

As indicated in FIG. 1 the auxiliary frame 28 is pivoted" relative to the base 22 about an: upright axis AA. Above the plate 29, the auxiliary frame is formed with an angled support plate 151 with a base plate 152 atop it. For convenience in setting the machine up for a job, plate 152' may be made-adjustable relative to plate 151 in any of a variety of ways which a mechanic skilled in this art will recognize as convenient, On the plate 152 is an upright wall 153 supported by' a gusset 154, upper sidewalls 1'56- and 157, and a top, box-end wall 158 to give the auxiliary frame strength and rigidity. The lower part of sidewall 156has' a curved fore portion 159 which curves around under a ribbon storage reel now to be described.

A strip or ribbon 161' of raw material such as copper or stainless steel is supplied to the. machine in convenient coil form 160. The center of the coil will he slid over the four posts or rods 162. of a .reel 165 and against a flat annular sidewall 163. By expanding linkage means 170, the hand wheel 164 may be turned to adjust the effective diameter of. the four posts 162", to move them in or out; to fit the inside of a wide variety of coils; It will be observed from FIG. 1 that the auxiliary frame above the plates 151, 152 is tilted at a slight angle with respect to the vertical. This enables the ribbon reel 160 to remain stably against the single reel sidewall 163- without requiring one on each side of the reel. It also enables the rib-bon to be fed off. the reel, without. twisting it out of. the plate of the reel, into perfect alignment. with the guide. means just prior to the mandrels, as will hereinafter be explained.

The reel 165 ismounted. on a wall 166- of the auxiliary frame, having a. projecting hub 167 on which. is mounted a pulley 168 carrying a shaft 169 through the wall 166 and into driving engagement with the reel. Amotor 171, angle drive 172, and belt 173 drive the reel automatically as will next be described.

The ribbon 161 is automatically maintained in a preferabl-y long loop extending toward the floor, by the following control apparatus. A roller 176 is lightly engaged within the. ribbon. loop and is mounted on the end of an arm 177 of a switch 178. Whenever theloop shortens, by feed onto the mandrels,v sufficiently to raise the switch arm 177a predetermined amount, it closes a circuit (not shown) which starts motor 171. This rotates the reel to drive off a predetermined amount of the ribbon 161 to a point where switch. lever 177 drops-and stops the motor 171.

The guide means for guiding the ribbon or strip 161 onto the mandrels will now be described. At this point, attention is directed tothe factv that the strip may be extremely thin, almost flimsy, and no kind of guide forceably abutting the edges, as is commonly used with thicker strip, will be effective. It is essential that the strip-arrive at the welding point on the mandrels with the edges perfectly smooth and unbroken. As. above described, the strip 161 is trained in a long gentle loop, inv some cases almost all the way to the floor, and then looped back, up, overa roller 174. Note that. this roller is considerably wider than necessary for the particular strip shown in FIG. 1. The reason for this is that the roller can support stripsof different widths depending on the size of present machine is quite versatile in this respect.

Beyond the roller 174, the strip. passes up a flat guide plate 179, diagonally toward the mandrels; A. pair of upstanding side plates 181 are provided on both sides of the ribbon and the spacing between these side plates is adjustable for dilferentwidths of ribbon. Referring now to FIG. 11, the ribbon 161 is fed forward, diagonally, onto the first mandrel, in a direction which is counter to the rotation. of the first mandrel. The ribbon makes a. first complete wrap about the first mandrel and meets its second wrap substantially at a point 182 which is over the welding space 128 previously described. At this point, as shown in FIGS. 7 and 10, there is an electric fusion welding electrode 183 which continuously welds the meeting edges of successive wraps to produce spiral welded tubing 184 on the second mandrel. An argon-shielded, tungsten-electrode, arc-welding procedure is employed in this embodiment of the invention.

The guide plate 1'79 approaches the first mandrel diagonally, at an angle of approach designated A/F in FIG. 11. In addition, by reason of the angled mounting of theplates 151, 152 (FIG. 1), the guide plate 179 is canted, that is, tilted slightly clockwise so that its right edge portion is lower than its left edge portion. This guides the ribbon 161 into tangency with the surface of the first mandrel along a line which is indicated as a broken line TT in FIG. 11. Note that this line of t'angency is non-parallel to the axis ofthe mandrels and the right-hand edge of the entering strip 161 is somewhat in advance of the welding point 182. In other words, at theline TT, the strip is on the cylindrical surfaces of the mandrels, ready for a perfect weld. It will also be observed in FIG. 11 that the point of tangency of the right-hand edge of the approachingstrip 161 is somewhat in advance of the welding space 128. This provides a complete wrap, forming a substantially gastightouter enclosure for the welding space 128.

When fusion welding the circumferential or helical seam on the rotating assembly, it is important to weld ahead of the top center to permit the molten pool of metal to freeze before it is far enough over the hill to allow the molten metal to run ahead of its corresponding base metal with resulting loss of control of the weld contour. An important function of the angled approach plate 179 and sub-base 2'9, 151 is to bring the ribbon uphill to the mandrels, bring the edges together ahead of top center, and allow the welding arc to be usedahead of top center. Line TT is slightly skewed (FIG. 11) and entirely ahead of top center position. The skew allows a slight excess of metal to form a slight weld bead or reinforcement; it is not significantly depended upon for weld pressure. Pressure is supplied by the contra-rotating mandrels and the resultant frictional force vectors.

A feature of this machine which facilitates handling extremely thin material is that the ribbon coil is in the same upright plane (which is angled, as shown in FIG. 1) as the guide 179. Furthermore, the upper guide surface. offthe latter is parallel to the axis of the reel. By this arrangement, the ribbon 161 is fed from the reel, without warping or twisting, onto the guide 179. This is important in handling fragile metallic-ribbon for the present purpose.

The: length of the second mandrel 139 in frictional contact with the ribbon wraps is greater than that of the first mandrel. This biases the finished spiral welded tubing 18.4; to rotate in the direction of the second mandrel as the. tubing'is being produced and fed off the machine.

Power means for feeding the ribbon 161 onto the mandrels comprises endless belt means which in the present case takes the form of a pair of flexible rubber belts 186, 187,.driven by a motor 188. This will now be described.

The motor 188 (FIG. 1) drives a speed reducer 189 which drives a belt 191 and pulley 192 on angle drive 193. The latter drives a chain 194 which rotates a sprocket 196 to cross shaft 197. On that shaft is a pair of belt pulleys 198, 198 about which the pair of belts 186, 187 is wrapped. The belts are then trained upward, first about a relatively wide idler 199, then up to a tensioning pulley cluster 201 which is pulled upward by a chain 202 passing over rollers 203 and 204 and down into a tubular housing 205 containing a weight 256 on the end of the chain. The weight, of course, is adjustable to vary the tension on the driving belts 186, 187.

From the pulley cluster 201 the drive belts pass down- '7 ward, again around the idler 199, forward to the idler pulleys 207, 207 carried on cross shaft 208 and thence toward, between, and parallel to the guides 181, along the top of the ribbon 161 on guide 179. Now, referring to FIGS. 10 and 11, the belts then follow the first complete wrap of the ribbon as it passes around the first mandrel, peel off at the second wrap, and return to the previously described pulleys 198, 1% to complete their orbital path. Note that the pairs of drive belts 186, 187 are spaced apart far enough, along the length of the mandrels, to enable the welding operation to be performed therebetween.

The spacing between drive belts 186, 187 to accommodate ribbons of different widths is readily varied by changing the spacing between the pairs of pulleys 198, 201 and 20 7.

As best shown in FIG. 10, a pair of hold-down rollers 209 is shown atop the drive belts, backing them, and maintaining the ribbon 161 in flatwise engagement with the top surface of the guide 179 to direct the ribbon onto the first mandrel in a straightline, tangential relation. This provides a beneficial effect in lining up the edges of the ribbon wraps for welding at a point 182.

Another device which has been found helpful in some cases in maintaining alignment of the edges just prior to weldingis a hold-down bar 212, shown in FIGS. 7 and 10. This might serve a dual function as described in conjunction with FIG. 12.

The use and operation of the apparatus will now be described as it is set up to produce one specific kind and size of spiral tubing, namely copper tubing having an outside diameter of 1.407" and an inside diameter of 1.375".

In this case, the ribbon or strip 161 would be selected approximately 2%" wide and .016" thick. The machine would be set up with a diagonal angle of feed A/F (FIG. 11) at about 37 /2 degrees. The speeds of the mandrels as controlled by the adjusting wheels 138 and 146 would be approximately 20 rpm. for the first mandrel and minus r.p.m. for the second mandrel, counterrotating in the directions of the arrows in FIG. 11. Under these conditions, finished spiral-welded tubing would come off the end of the second mandrel at the rate of approximately 2 lineal feet per minute. If desired, an automatic hammer (not shown) may be provided to smooth the spiral welded joint, and a flying saw to cut off the finished tubing.

The production speed will be limited only by the limitations of the welding process employed. FIG. 12 shows, in schematic representation, an alternate welding method employing radio frequency energy. A radio frequency transformer secondary 216 is provided with leads to two contact shoes or brushes 217, 218 contacting the two edges to be welded slightly in advance of the point of convergence 182a. Current would concentrate along the converging edges and enable welding at very high speeds. Suitable primary energy means (not shown) would be provided to generate radio frequency current (200 to 500 kilocycles or more) in the secondary and in the metal ribbon. The shoe or brush 217 may take the form of the guide bar 212 in order to combine both conductive and hold-down functions.

In the case of the FIG. 12 welding method, it would be possible to reduce the upward inclination of the guide plate 179 which provides the uphill approach to the mandrel assembly, since the weld would be completed almost instantaneously as the edges converge.

While one form in which the present invention may beembodied has been shown and described, it will be understood that various modifications may be made within the spirit and scope of the invention which should be limited only by the appended claims.

I claim:

1. In apparatus for forming spiral tubing from a ribbon of material,

first and second tubular, rotatable mandrels axially aligned in endwise relation;

means for guiding and continuously feeding a ribbon of material diagonally onto and around said first I and second mandrels in succession;

means for rotating said first mandrel in one direction which is opposite the direction of wrap of the ribbon feeding thereon; means for rotating saidsecond mandrel opposite said first mandrel; and securing means intermediate the ends of said mandrels for securing the meeting edges of successive wraps of said ribbon to produce spiral tubing on said second mandrel.

2. In apparatus for forming spiral tubing from a ribbon of material, the combination of claim 1 in which the length of second mandrel in frictional engagement with said ribbon is greater than the length of first mandrel in frictional engagement with said ribbon, to bias the produced spiral tubing to rotate in the same direction as the second mandrel.

3. In apparatus for forming spiral tubing from a ribbon of material, the combination of claim 1 including mandrel speed control means by which the relative speed between the mandrels may be adjusted to vary the pressure between meeting edges of successive wraps at said securing means.

4. In apparatus for forming spiral tubing from a ribbon of weldable material,

first and second tubular, rotatable mandrels axially aligned in endwise relation; means for guiding and continuously feeding a ribbon of weldable material diagonally onto and around said first and second mandrels in succession;

means for rotating said first mandrel in one direction which is opposite the direction of wrap of the ribbon feeding thereon;

means for rotating said second mandrel opposite said first mandrel; and

welding means at the juncture between said mandrels for welding the meeting edges of successive wraps of said ribbon to produce spiral welded tubing on said second mandrel.

5. In apparatus for forming spiral tubing from a ribbon of weldable material,

first and second tubular, rotatable mandrels axially aligned and axially separated with a space therebetween;

means for guiding and continuously feeding a ribbon of material diagonally onto said first mandrel and in diagonal wraps around said first and second mandrels in succession; means for rotating said first mandrel in one direction which is opposite the direction of feed of the ribbon feeding thereon; 4

means for rotating said second mandrel in a direction opposite said first mandrel; and

welding means at said space between the mandrels for welding the meeting edges of successive wraps of said ribbon to produce spiral tubing on said second mandrel.

6. In apparatus for forming spiral tubing from a ribbon of weldable material,

first and second tubular, rotatable mandrels axially aligned and axially separated with a space therebetween;

guide and feed means for guiding and feeding a ribbon of material diagonally onto said first mandrel and in diagonal abutting wraps around said first and second mandrels in succession, said guide' and feed means being oriented to make the first wrap substantially complete about the first mandrel and meeting the second wrap at a point over said space to substantially completely enclose said space;

means for rotating said first mandrel in one direction ribbon of weldable material,

a mandrelsupport frame;

a pair of tubular, concentric drive shafts journaled for rotation relative to the frame and to one another;

first; and second tubular mandrels mounted respectively on said shafts, said mandrels being axially aligned in endwise relation;

means for guiding and continuously feeding a ribbon of material diagonally onto said first mandrel and in diagonal wraps around said first and second mandrels in succession;

driving mean-s for driving said drive shafts and their respective mandrels in opposite directions with the first mandrel being driven in a direction which is opposite the direction of feed of the ribbon;

welding means at the juncture between said mandrels for welding the meeting edges of successive Wraps of said ribbon to said second mandrel;

a cooling tube concentric within said second tubular drive shaft, rotatable therewith, and extending into the second mandrel;

rotating coupling means at the outer end of said second shaft coupled respectively with cooling fluid inlet and outlet ports through a cooling circuit which includes passages inside and outside of said cooling tube and the interior of said second mandrel to withdraw heat from the spiral Welded tubing on the second mandrel.

8. In apparatus for forming spiral tubing from a ribbon of material,

a mandrel support frame;

first and second tubular, rotatable mandrels axially aligned in endwise relation and jour'na-led for rotation with respect to saidsupport frame;

an auxiliary frame;

guide means supported on said auxiliary frame for guiding a ribbon of material diagonally onto said first mandrel;

feeding means supported on said auxiliary frame for feeding said ribbon along said guide means and in diagonal wraps around said first and second mandrels in succession;

means for driving said mandrels in opposite directions with the first mandrel being driven in a direction which is opposite the direction of wrap. of the ribbon;

a ribbon storage reel supported on said auxiliary frame and aligned with. said guide. means to feed ribbon to the mandrels via the guide means;

said mandrel support frame having supported thereon securing means intermediate the ends of the mandrels for securing the meeting edges of successive wraps of ribbon to produce spiral tubing on said second mandrel;

said auxiliary frame being pivoted on the mandrel support frame for adjustment about an axis which extends generally in a direction to intersect an area adjacent the securing means;

whereby the guide means and ribbon storage reel may be pivotally adjusted about said axis relative to said mandrels to adjust the angle of approach of the ribbon to the mandrels to enable the use of different produce spiral welded tubing on- 16 width ribbons and different diameter mandrels in producing tubing of preselected size. 9. In apparatus for forming spiral tubing from a ribbon of material, the combination of claim 8 in which the ribbon storage reel, the feeding means and the guide means are constructed to accommodate different widths of ribbon.

10. In apparatus for forming spiral tubing from a ribbon of Weldable material,

first and second tubular, rotatable mandrels axially aligned in endwise relation; 7

guide means for guiding a ribbon of material diagonally onto and in wraps around said first and second mandrels in succession;

means for driving said mandrels in opposite directions with the first mandrel rotating in the direction to oppose the wrap of ribbon;

ribbon feeding means including endless flexible belt means trained for movement in an orbital path 7 along said guide means and parallel thereto and following at least the first ribbon Wrap about the mandrels; said endless flexible belt means having a frictional surface engageable with the ribbon; means for tensioning the belt means to frictionally engage the ri bbon as it wraps around said mandrels; drive means for moving said belt means in said orbital path; and

welding means adjacent said mandrels in an area where the meeting edges of successive wraps of ribbon conform with the mandrels and with one another for continuously welding said. meeting edges to produce spiral tubing on said second mandrel.

11. In apparatus for forming spiral tubing from a ribbon of welda-ble material, the combination of claim 10 including hold-down roller means backing said belt means on the exit end portion of the guide means to constrain said ribbon to approach said first mandrel in a straightline tangential relation.

. 12. In apparatus for forming spiral tubing from a ribbon of weldable material, the combination of claim 10 in which said belt means includes. a pair of belts running along in spaced apart, side-by-side relationship and means for varying the spacing between said belts to accommodatewidths of ribbon.

13. In apparatus for forming spiral tubing from a ribbon of weldable material, the combination of claim 10 in which successive belt wraps are positioned over the first and second mandrels respectively and spaced apart sufiiciently, lengthwise. of the mandrels, to provide an area for a continuous welding operation therein, and welding means in said area between said belt wraps for continuously welding the meeting edges of successive ribbon wraps to produce spiral tubing on said second. mandrel. 14-. In apparatus for forming spiral tubing from a ri bon of material,

first and second tubular, rotatable mandrels axially aligned in endwise relation; means for guiding and continuously feeding, a ribbon of material froin a loose loop diagonally onto and around said first and second. mandrels in succession; a ribbon storage reel above said loop from which ribbon is payed into said loop, means for driving said reel to pay ribbon into said loop, sensing means for sensing a condition of said loop, and control means responsive to said sensing means for automatically actuating said driving means to pay out ribbon to maintain said loop in a predetermined condition; means for rotating said first mandrel in one direction which is opposite the direction of wrap of the ribbon feeding thereon; means for rotating said second mandrel opposite said first mandrel; and

means intermediate the ends of mandrels for securing the meeting edges of successive wraps of said ribbon to produce spiral tubing on said second mandrel.

15. In apparatus for forming spiral tubing from a ribbon of weldable material,

first and second tubular, rotatable mandrels axially aligned in endwise relation;

an elongated guide diagonally approaching said first mandrel to guide a ribbon of weldable material diagonally toward said first mandrel;

drive means for said ribbon effective to feed it along said guide and diagonally onto and in wraps around said first and second mandrels in succession;

means for rotating said first mandrel in one direction which is opposite the direction of wrap of the ribbon feeding thereon;

means for rotating said second mandrel opposite said first mandrel;

welding means at the juncture between said mandrels for welding the meeting edges of successive wraps of said ribbon to produce spiral welded tubing on said second mandrel; and

. said guide means being canted about its length to guide the ribbon into tangenecy with the surface of the first mandrel along a line on said surface which is non-parallel to the mandrel and is in advance of the welding means.

16. In apparatus for forming spiral tubing from a ribbon of weldable material,

first and second tubular, rotatable mandrels axially aligned in endwise relation; a storage reel for a weldable ribbon rotatable about an axis to pay off ribbon in a plane parallel to said axis;

an. elongated guide coplanar with the reel and havinga ribbon-guiding surface which is parallel with the axis of the reel;

the reel and the ribbon-guiding surface being in a plane which intersects the first mandrel diagonally for feeding a ribbon in said plane from the reel, along the ribbon-guiding surface, and thence diagonally toward said first mandrel without warping or twisting said ribbon;

drive means for said ribbon effective to feed it along said guide and diagonally onto and in wraps around said first and second mandrels in succession;

means for rotating said first mandrel in one direction which is opposite the direction of wrap of the ribbon feeding thereon;

means for rotating said second mandrel opposite said first mandrel;

welding means at the juncture between said mandrels for welding the meeting edges of successive wraps of said ribbon to produce spiral welded tubing on said second mandrel; and

said guide means being canted about its length to guide the ribbon into tangency with the surface of the first mendrel along a line on said surface which is nonparallel to the mandrel and is in advance of the welding means.

17. In apparatus for forming spiral tubing from a ribbon of weldable material, support frame means having: a pair of tubular, horizontal, concentric drive shafts journaled for rotation relative to the frame and to one another;

first and second tubular rotatable, horizontal mandrels mounted respectively on said shafts, said mandrels being axially aligned in endwise relation with a welding space therebetween;

a reel having a coil of ribbon Wound thereon, a loose loop 'of ribbon depending therefrom, and a ribbon guide, all disposed in an upright non-vertical plane diagonally intersecting said first mandrel adjacent said welding space;

reel driving means for paying ribbon into said loose loop and effective to maintain a predetermined condition of slack in said loop;

said ribbon being trained from said loose loop, along said guide and diagonally onto and in abutting spiral wraps around said first and second mandrels in succession;

ribbon feeding means including: 7

an endless friction belt extending along the ribbon on said guide and around successive Wraps of ribbon about the first and second mandrels,

driving means for moving said friction belt in an orbital path from said guide onto said mandrels to feed ribbon in that direction,

said friction belt following said ribbon about said mandrels in a spiral path with an open area between belt wraps, thereby exposing the meeting edges of the corresponding ribbon wraps at said welding space between the mandrels; first mandrel driving means for rotating the first mandrel drive shaft to rotate said first mandrelin one direction which is opposite the direction of wrap of the ribbon being fed thereon; second mandrel driving means for rotating the second mandrel drive shaft in a direction to rotate the second mandrel opposite said first mandrel; control means for the mandrel driving means for varying the speed of either mandrel independent of the other; welding means at said open area between said belt wraps for continuously welding the meeting edges of successive wraps of ribbon over said welding space :10 produce spiral welded tubing on said second manrel; means for conducting gas through said drive shafts to said welding space; and means for conducting cooling fluid to and from the second mandrel through said drive shafts.

References Cited by the Examiner UNITED STATES PATENTS 8/1955 Fay 228-17 3/ 1965 Napieo et al. 22817 8/1966 Groves et al. 228-49

Claims (1)

1. IN APPARATUS FOR FORMING SPIRAL TUBING FROM A RIBBON OF MATERIAL, FIRST AND SECOND TUBULAR, ROTATABLE MANDRELS AXIALLY ALIGNED IN ENDWISE RELATION; MEANS FOR GUIDING AND CONTINUOUSLY FEEDING A RIBBON OF MATERIAL DIAGONALLY ONTO AND AROUND SAID FIRST AND SECOND MANDRELS IN SUCCESSION; MEANS FOR ROTATING SAID FIRST MANDREL IN ONE DIRECTION WHICH IS OPPOSITE THE DIRECTION OF WRAP OF THE RIBBON FEEDING THEREON; MEANS FOR ROTATING SAID SECOND MANDREL OPPOSITE SAID FIRST MANDREL; AND SECURING MEANS INTERMEDIATE THE ENDS OF SAID MANDRELS FOR SECURING THE MEETING EDGES OF SUCCESSIVE WRAPS OF SAID RIBBON TO PRODUCE SPIRAL TUBING ON SAID SECOND MANDREL.

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