US3240042A

US3240042A - Fabricated tubing and the method and apparatus for producing the same

Info

Publication number: US3240042A
Application number: US201515A
Authority: US
Inventors: Edward P Habdas
Original assignee: Calumet and Hecla Inc
Current assignee: Calumet and Hecla Inc
Priority date: 1962-06-11
Filing date: 1962-06-11
Publication date: 1966-03-15
Anticipated expiration: 1983-03-15
Also published as: GB975697A; DE1452234A1; SE315449B

Description

March 15, 1966 E. P. HABDAS 3,240,042 FABRICATED TUBING AND THE METHOD AND APPARATUS FOR PRODUCING THE SAME Filed June 11. 1962 INVENTOR.

United States Patent 3,240,042 FABRICATED TUBING AND THE METHOD AND APPARATUS FOR PRODUCING THE SAME Edward P. Habdas, Dearborn, Mich, assignor to Calumet & Hecla, Ina, Allen Park, Mich., a corporation of Michigan Filed lune 11, 1962, Ser. No. 201,515 10 Claims. (Cl. 72-49) The present invention relates to fabricated tubing and the method and apparatus for producing the same.

It is an object of the present invention to provide tubing fabricated from continuous flat strip having its edges turned up to provide a substantially U-shaped cross section and having its edges tapered to provide for winding the strip in a helical form to bring sides of the edge flanges into contact and having the abutting sides of said edge flanges bonded together.

It is a further object of the present invention to provide tubing of the character described in the preceding paragraph in which the inter-bonded edge flanges are formed downwardly against the outside diameter of the tubing.

It is a further object of the present invention to provide a method of making tubing which comprises continuously advancing a flat strip longitudinally, forming the edge portions of the strip to extend perpendicular to the plane thereof so as to form a strip of generally U-shaped cross-section, thereafter rolling or otherwise forming the bent up edge portions or flanges of the strip to a tapered cross-section to accommodate the strip to coiling to helical formation, thereafter coiling the strip to bring outside side surfaces of the edge flanges into abutment, and bonding the edge flanges together to form continuous tubing.

It is a further object of the present invention, as described in the preceding paragraph, to provide a method in which the strip with its bent up and tapered edge flanges is coiled on a rotating cylindrical mandrel.

It is a further object of the present invention, as described in either of the two preceding paragraphs, to provide a method of forming tubing which includes the step of forming the bonded generally radially projecting flange portions inwardly to lie against the outer cylindrical surface of the tubing.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, illustrating a preferred embodiment of the invention, wherein:

FIGURE 1 is a more or less diagrammatic view illustrating the method of forming tubing and illustrating the finished tubing in alternative forms.

FIGURE 2 is a fragmentary section on the line 22, FIGURE 1.

FIGURE 3 is a fragmentary section on the line 33, FIGURE 1.

FIGURE 4 is a fragmentary enlarged section on the line 4-4, FIGURE 1.

FIGURE 5 is a fragmentary enlarged sectional view on the line 5-5, FIGURE 1.

The present invention includes tubing of any convenient size but is particularly useful in the production of relatively large light-walled tubing such for example as is used in irrigation fields. Tubing of this type is generally transported manually from place to place and since it is not subjected to any substantial internal pressure, it may be relatively thin-walled.

However, it is necessary for the tubing to be sufliciently stiff so as to permit its transportation without alteration of its generally cylindrical configuration.

As seen in FIGURE 1, such tubing is indicated generally at where it is shown as locate-d on a rotating mandrel 12. The portion of the tubing seen at 10a includes a helical flange, fin or bead 14, the nature and method of production of which will subsequently be described. For the present however, it is to be noted that this continuous helical flange constitutes a stiffening means which renders a substantial length of the tubing self-supporting, at least suificiently so as to permit ready transportation.

If designed, and as a modification of the tubing having the configuration illustrated in the zone designated 10a, the tubing may have the configuration designated in the zone 10b in which the flange is bent over and flattened against the outer cylindrical surface of the tubing as indicated at 14b.

It will of course be apparent that for maximum stiffness it is preferred to leave the flange 14 extending generally radially outwardly from the tubing as designated in the zone 10a. Where such stiffness is not required the flange may be bent down as indicated at 14b.

The method of producing the tubing is apparent from FIGURE 1 in which continuous flat strip 20 is advanced for example from a storage reel, through a forming station designated 21 in which inner forming

rolls

22 and 24 are carried by a support 26 and cooperate with outer forming

rolls

27 and 28 respectively. The advance of the flat stock through the forming station 21 results in forming predetermined edge portions of the strip upwardly into

individual flanges

30 and 32, as best seen in FIG- URE 2. Since the operation carried out at the forming station 21 is essentially a bending operation, it will of course be apparent that the bent up

flanges

30 and 32 are of uniform thickness from edge to edge and that accordingly, the strip 20 as it advances beyond the forming station 21 is essentially a flat strip.

At a forming station 34 means are provided for edge thinning or tapering the

edge flanges

30 and 32 to the tapered cross-section illustrated at 30a and 32a in FIG- URE 3. This tapering operation is accomplished by

edge thinning rolls

35 and 36 operating against a stationary anvil 38. Inasmuch as the

edge flanges

30 and 32 are tapered substantially uniformly, the tapered flanges may be made to conform to a curvature of the intermediate portion of the strip 20 which permits it to be formed around the cylindrical mandrel 12. In order to carry out this operation most efficiently, the anvil 38 and the

thinning rolls

35 and 36 are located as closely as possible to the zone of tan-gency between the advancing generally flat strip 20 with the cylindrical surface of the mandrel 12. Thus, referring to FIGURE 1, it will be observed that the

rolls

35 and 36 are in alignment with the axis of the mandrel 1-2 and hence, are not located directly opposite each other across the width of the advancing strip 20. This arrangement tends to form the strip into a helical path and its exact position is determined by engagement with the rotating mandrel.

In FIGURE 1 the roll 36 operates with the anvil 38 to form the right hand flange 32 into the required tapered form by direct engagement with opposite sides thereof. The roll 35 however, cooperates with the mandrel to engage not only the flange 30 of the advancing stripbut also the first convolution of the flange 32 so as to produce the configuration illustrated in FIGURE 4.

Instead of having the roll 35 operate to taper the flange against the anvil 38 as suggested in FIGURE 1, it may operate in advance of the full line position as for example in the dotted line position designated 35a, in which case it will impart a taper to the flange 30 to the shape illustrated at 30a, FIGURE 3, prior to engagement of the flange 30a with the flange 32a of the preceding convolution. Roll 36 is then preferably operated in the position 36a.

In addition to edge thinning or tapering the

flanges

30 and 32 to the configuration illustrated at 30a and 32a, the anvil 38 and the roll 36 serve as abutment means insuring continuous advance of the helically coiled strip on the rotating mandrel. Since the direction of advance of the strip as it engages the surface of the mandrel is different from the instantaneous direction of the engaged surface of the mandrel, it will of course be apparent that the tube assembly is in effect sliding continuously longitudinally on the mandrel.

Means are provided for bonding the confronting surfaces of the

tapered flanges

30a and 32a so as to form the helically wound strip into a continuous sealed tube. This means is illustrated in FIGURE 1 as taking the form of a pair of welding electrodes 40 and 4-2 shaped to press the

flanges

30a and 32a into firm contact and to effect a weld by elevating the temperature of the flanges by current passing therethrough from a source diagrammatically indicated at 44. Obviously, the welding action may be controlled by the pressure exerted on the flanges by the electrodes 49 and 42, the angular extent of the electrodes, the welding current applied to the electrodes, and the rate of advance of the strip 20. It will further be understood that the welding operation as illustrated and described herein is merely one convenient method of effecting a satisfactory bonding of the strip, assuming that the material may be bonded by such an operation.

If desired, the composite double thickness flange 14 produced by

welding flanges

30a and 32a together may be left standing, in which case it serves as an efficient means for stiffening the composite tubing. It will of course be appreciated that the stiffening action may be varied by controlling the height of the helical fins and similarly, by controlling the thickness of the fins.

In some cases it may be preferred to eliminate the radially outstanding helically extending fin or flange 14, in which case a flattening roller 50 may be provided in position to engage the flange 14 and to flatten it downwardly against the cylindrical surface of the tubing as shown in the zone In this case the finished tubing at the zone of the bonded connection between adjacent convolutions will have the appearance shown in FIG- URE 5, where the flange 14b is shown as flattened down against the surface of the tubing.

Advance of the strip onto the mandrel may be accomplished by rotating the mandrel and drawing the strip through the sets of

rolls

22, 24, 27 and 28, and 35, 36. However, since the invention finds its most eflicient operation in the production of relatively thin-walled tubing, it will ordinarily be desirable to effect powered rotation of the rollers which form the edges of the strip into U- shaped configuration as well as the edge thinning or tapering rolls. The rolls may conveniently be driven in such a way that they reduce the tension in the strip but the actual rate of advance of the strip is determined by the speed of rotation of the mandrel 12. In other words, power is applied to the

rolls

34, 36 and either 22 and 24 or 27 and 28 so that tension in the strip intermediate the sets of rolls and intermediate the

rolls

35, 36 and the mandrel is substantially less than if the strip were to be pulled through the roll devices solely by tension developed from the rotating mandrel.

While the present invention is particularly applicable to the production of 'metal tubing such for example as aluminum or aluminum alloy tubing, it is apparent that it might be applied to the production of plastic tubing, in which event elements 40 and 42 instead of being electrodes for passing welding current through the flanges, would be electrically heated elements effective to produce a bond in the plastic material by the application of heat and pressure.

The drawings and the foregoing specification constitute a description of the improved fabricated tubing and the method and apparatus for producing the same in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. Apparatus for producing continuous tubing from flat strip material which comprises a mandrel, means for rotating the mandrel, means for advancing flat strip material longitudinally in a plane tangent to the mandrel and in a direction oblique to the axis of the mandrel, roll means for bending the edges of the strip material to form flanges extending in the same direction from the plane of the strip, roll tapering means engageable with the flanges in a zone closely adjacent to the mandrel to taper the thickness of the flanges outwardly so as to produce a helical form to the strip to assist in coiling it in helical convolutions on the rotating mandrel with the flanges of adjacent convolutions thereof in abutment, and means engageable with the abutting tapered flanges of the coiled strip on the mandrel for bonding the contacting surfaces of the flanges together, the roll tapering means comprising an anvil located substantially at the zone of tangency between the advancing strip and the surface of the mandrel, a first roll cooperating with an anvil to taper the flange at the edge of the strip remote from the previously formed convolutions to a predetermined taper effective to coil the tapered flange helically to conform to the mandrel, a second roll cooperating with the anvil in a position to engage the previously tapered flange of the preceding convolution and the adjacent untapered flange of the advancing strip and to taper the advancing flange of the strip to cause it to coil helically in conformity with the diameter of the rotating mandrel and simultaneously to press the tapered flanges of the adjacent convolutions firmly together.

2. Apparatus for producing continuous tubing from flat strip material which comprises a mandrel, means for rotating the mandrel, means for advancing flat strip material longitudinally in a plane tangent to the mandrel and in a direction oblique to the axis of the mandrel, roll means for bending the edges of the strip material to form flanges extending in the same direction from the plane of the strip, roll tapering means engageable with the flanges in a zone closely adjacent to the mandrel to taper the thickness of the flanges outwardly so as to produce a helical form to the strip to assist in coiling it in helical convolutions on the rotating mandrel with the flanges of adjacent convolutions thereof in abutment, and means engageable with the abutting tapered flanges of the coiled strip on the mandrel for bonding the contacting surfaces of the flanges together, the roll tapering means comprising an anvil located substantially at the zone of tangency between the advancing strip and the surface of the mandrel, a first roll cooperating with an anvil to taper the flange at the edge of the strip remote from the previously formed convolutions to a predetermined taper effective to coil the tapered flange helically to conform to the mandrel, a second roll cooperating with the anvil at a point in advance of the zone of tangency between the advancing strip and the surface of the mandrel shaped to taper the thickness of the flange at the edge of the advancing strip adjacent previously formed convolutions to a tapered configuration designed to coil the tapered flange into conformity with the diameter of the rotating mandrel.

3. Apparatus for producing continuous tubing which comprises a cylindrical mandrel, means for rotating the mandrel in a fixed position, means for advancing a strip comprising a flat web and edge flanges bent to extend in the same direction from the web to form a channel-shaped cross-section substantially tangentially of the mandrel and in a direction oblique to the axis of said mandrel, taper means adjacent the zone of tangency of the web to said mandrel comprising means for applying pressure progressively longitudinally of said flanges between opposite edges thereof, said taper means comprising means located wiithin the channel of said advancing strip substantially at the zone of tangency with said mandrel and engaging the inner surfaces of the flanges thereof, means to apply pressure progressively longitudinally to the outer surfaces of said flanges, and means for bonding the tapered flanges of adjacent convolutions of said strip together.

4. Apparatus as defined in claim 3 in which said last means comprises one roll engageable directly with the outer surface of the flange at the edge of the strip opposite to the direction of advance of the completed tube.

5. Apparatus as defined in claim 3 in which said last means comprises one roll engageable directly with the outer surface of the flange at the edge of the strip opposite to the direction of advance of the completed tube, and a second roll engageable with the inner surface of said last mentioned flange after it has been coiled into engagement with the outer surface of the other flange of said strip at the zone of tangency with said mandrel.

6. Apparatus as defined in claim 3 in which said last means comprises rolls engageable directly with the outer surfaces of both of said flanges.

7. The method of making fabricated tubing which comprises advancing a strip having a flat central web and edge flanges bent in the same direction to form a channelshaped cross-section toward a rotating cylindrical mandrel in a direction substantially tangent to the mandrel and at an angle oblique to its axis, substantially at the point of tangency with the mandrel rolling both of the edge flanges longitudinally of the strip to an outwardly tapered cross-section and substantially simultaneously coiling the strip around the mandrel into a closed tubular configuration with outer surfaces of the tapered flanges in contact, and bonding the surfaces of said flanges together to form a continuous tube.

8. The method as defined in claim 7 which comprises sliding the completed tubing longitudinally on the rotating mandrel as new convolutions are added by continued advance of the strip.

9. The method as defined in claim 7 in which the step of tapering the flanges comprises advancing each of the flanges between forming devices including rolls having axes disposed substantially perpendicular to the plane of the flat web of the strip.

10. The method as defined in claim 7 in which the step of tapering of the flanges comprises applying rolling pressure progressively longitudinally of one flange, coiling the strip to bring the tapered flange into side abutment with an untapered flange at the opposite edge of said strip from said one flange, and tapering said other flange by applying rolling pressure progressively longitudinally of said flanges to both of said flanges.

References Cited by the Examiner UNITED STATES PATENTS 470,738 3/1892 Bayles 138--154 1,263,340 4/1918 Silk 138154 1,840,317 1/1932 Horvath 15364.5 1,918,137 7/1933 Scarritt 113--35 2,233,233 2/1941 Williams 11335 2,734,471 2/1956 Bornand 11335 2,752,873 7/1956 Freeze 113-35 2,812,794 11/1957 Chapman 153-645 3,000,084 9/1961 Garland 15364.5

CHARLES W. LANHAM, Primary Examiner.

NEDWIN BERGER, MICHAEL V. BRINDISI,

Examiners.

R. J. HERBST, E. D. OCONNOR, Assistant Examiners.

Claims

1. APPARATUS FOR PRODUCING CONTINUOUS TUBING FROM FLAT STRIP MATERIAL WHICH COMPRISES A MANDREL, FOR ROTATING THE MANDREL, MEANS FOR ADVANCING FLAT STRIP MATERIAL LONGITUDINALLY IN A PLANE TANGENT TO THE MANDREL, ROLL MEANS DIRECTION OBLIQUE TO THE AXIS OF THE MANDREL, ROLL MEANS FOR BENDING THE EDGES OF THE STRIP MATERIAL TO FORM FLANGES EXTENDING IN THE SAME DIRECTION FROM THE PLNE OF THE STRIP, ROLL TAPERING MEANS ENGAGEABLE WITH THE FLANGES IN A ZONE CLOSELY ADJACENT TO THE MANDREL TO TAPER THE THICKNESS OF THE FLANGES OUTWARDLY SO AS TO PRODUCE A HELICAL FORM TO THE STRIP TO ASSIST IN COILING IT IN HELICAL CONVOLUTIONS ON THE ROTATING MANDREL WITH THE FLANGES OF ADJACENT CONVOLUTIONS THEREOF IN ABUTMENT, AND MEANS ENGAGEABLE WITH THE ABUTTING TAPERED FLANGES OF THE COILED STRIP ON THE MANDREL FOR BONDING THE CONTACTING SURFACES OF THE FLANGES TOGETHER, THE ROLL TAPERING MEANS COMPRISING AN ANVIL LOCATED SUBSTANTIALLY AT THE ZONE OF TANGENCY BETWEEN THE ADVANCING STRIP AND THE SURFACE OF THE MANDREL, A FIRST ROLL COOPERATING WITH AN ANVIL TO TAPER THE FLANGE AT THE EDGE OF THE STRIP REMOTE FROM THE PREVIOUSLY FORMED CONVOLUTIONS TO A PREDETERMINED TAPER EFFECTIVE TO COIL THE TAPERED FLANGE HELICALLY TO CONFORM TO THE MANDREL, A SECOND ROLL COOPERATING WITH THE ANVIL IN A POSITION TO ENGAGE THE PREVIOUSLY TAPERED FLANGE OF THE PRECEDING CONVOLUTION AND THE ADJACENT UNTAPERED FLANGE OF THE ADVANCING STRIP AND THE TAPER THE ADVANCING FLANGE OF THE STRIP OF CAUSE IT TO COIL HELICALLY IN CONFORMITY WITH THE DIAMETER OF THE ROTATING MANDREL AND SIMULTANEOUSLY TO PRESS THE TAPERED FLANGES OF THE ADJACENT CONVOLUTIONS FIRMLY TOGETHER.