US1878376A - Machinery for making welded pipe - Google Patents

Description

Sept. 20, 1932 CAMMEN 1,373,376.

MACHINERY FOR mum wswan Pm Filed Feb. 4. 1931 O l s "3 w r m w INVENTOR. a 1%, @0140 Patented Sept. 20, 1 932 PATENT- OFFICE- LEON CAMMEN, OF NEW YORK, N. Y.

MACHINERY FOR MAKING WELDED II IE Application filed February 4, 1931. Serial No. 513,337.

The present invention relates to apparatus for making spiral pipe from a stri of sheet material. Spiral pipe is made by orming a strip of sheet metal into a helix and securing the meeting edges of successive turns of the helix as, for example, by welding.

The present invention has for an object to provide an improved method of and means for forming a strip of metal into a helix to make a pipe therefrom.

Another object is to provide an improved method and means for holding the successive turns of the helix in close engagement while uniting the same.

Another object is to provide unimproved method of and means for progressively contacting the meeting edges of successive turns with substantial pressure and welding them at the point of pressure.

Another object is to provide an improved arrangement for bending the sheet metal between bendin rolls.

Another ob ect is to provide means for first bending the sheet metal to 'form ahelix of 2.3 a size approximating that required for the final form of the pipe and thereafter further bending the-sheet metal to final form.

Another object is to provide an improved drive for rotating the pipe as formed.

The nature" and objects of the invention will be better understood from a description of an illustrative embodiment thereof and for the purpose of which description reference is made to the accompanying drawing forming a part hereof and in which Figure 1 is a somewhat diagrammatic sectional view showing a Selected embodiment of the invention;

Fig; 2 shows a view of the skelp, partly welded and artly unwelded, end view as seen by looking from the right to the left hand side of Fig. 1.

Fig. 3 shows, in vertical section, a view of one of the constructions for turning the pige.

ig. 4 shows, diagrammatically, the cycle of operationof the device shown'in Fig. 1.

The present invention refers, particularly to the type of machinery for making spirally 9 welded pipe wherein the skelp is passed between bending rolls, usually three, of which the one on the inside is shown at 1, while the outside rolls are not shown. 7 By properly setting the twist rolls (not shown) the edges of the seam, such as 27 and 28, shown here widely apart, may be brought together as closely as desired, even to the extent of overlapping, but it is impossible to produce a pressure in the seam just by the action of the twist and bending rolls. In another apo plication (Ser. No. 496,212) I have shown that to produce such a pressure it is necessary, first, to provide a guide, such as 8, bearing against the edge of the seam, such as 28; next, to produce by an application of power 5 a motion of rolling andadvancing in the welded part of the pipe within reasonable distance from the guide 8, and, finally, provide such an arrangement of parts that the diameter of the cylinder of skelp between the 7 forming rolls and the locus of welding is different from that of the welded part of the pipe.

The present invention deals with improved means to produce simultaneously the forward and turning motion of the welded part of the pipe, and to satisfy the following conditions in doing it: (1) Make it possible to apply enough force to cause -a pressure of the desired magnitude in the seam at the place of welding; (2) make the device effective even where the pipe is very smooth; (3) provide a device of such a type that it would be applb cable to a large range of sizes of pipe without material changes every time and large loss of time due to such changes. The motion of the welded part of the pipe will naturally induce a similar motion in the unwelded butcoiled part.

In Fig. 1, 1 is the end of the shaft of the 00 inside bending roll, with skelp 29 around it. It will be noted that the skelp at the bottom is in close contact with roll 1, or rather sleeve 31 thereof, but at the top of the skelp is quite far away from the roll. This is the natural condition in making spiral pipe. 2 is a stationary mandrel, substantially of the same diameter as the coiled skelp, and therefore of a diameter larger than that of roll 1.

Among other things it may carry guide 8.

Usually it will not be concentric with roll 1. Rolls 3 and 4 are shown in two pieces, 3 being much longer than 4; this is however merely a preferred design. These rolls are held on shaft 32 by means of a collar 33. These rolls line of mandrel 2 when extended coincides with a generating line of rolls 3 and 4. It is preferable that this common generating line should pass through or in the immediate proximity of guide 8, as shown in Fig. 1. A spacing between rolls 3 and 4 is provided, and that is, i. e. at 20, where the weldin takes place, the welding current being supp ied by discs 10 and 11.

Because of the fact that roll 3 is of smaller diameter than mandrel 2, the skelp 29 follows for a while, until say 29-a, the outline of mandrel 2 but, if twisted with enough power thereafter, tends to approach the diameter of rolls 3 and 4, and when this has been accomplished, follows the outline of 39. This is shown in Fig. 2. In order to produce this effect, two things are necessary, first, a twist exerted on the skelp located to the right of 20, and second, resistance to either the twist or forward motion of the part of the skelp located to the left of 20. The method to produce the former will be described hereafter; the resistance to this twist is in part produced by the presence of guide 8, and may be increased to any desired extent by applying some kind of a brake on the skelp to the left of 20. This latte. is not shown here.

The coiled skelp 29 is coming from the bending roll 1 and is passing over the mandrel 2 so as to bring guide 8 within the open seam 27-28; thereafter the skelp goes on to rolls 3"and 4 and is then subjected to the action of rope 12. This rope (Fig. 1) passes over the skelp making several turns about the welded part of the pipe (snubbing it), and is subjected at one end (42, Fig. 3) to an upward pull, of an intermittent nature, and at the other end to the action of weight 13 (or some other opposing force, e. g. spring). As the rope end at 42 is being ulled upwards, the pipe tends to turn in the direction of the arrow, Fig. 3, and at the same time, because of the presence of guide 8 in the open seam. the pipe has to move forward,

i. e. to the right in Fig. 1.

If the rope ends 13 and 42 were connected into an endless rope, and the weight replaced by a pulley under tension, e. g. an idler pulley, the effect would have been exactly the same as is obtained with the arrangement of rope shown in Fig. 3, and the drive would have been a combination of the well-known rope drive and forward propulsion by means of guide 8, neither of which is new and the combination is not sufficiently novel to be worth claiming even if it did work as required here, which it does not.

The reason why a combination of an endless rope drive or its equivalent with a guide pin such as 8 will not work is that it calls for two non-compatible actions to be performed simultaneously. Assume that we do have an endless rope drive: obviously, in order to move to the right in Fig. 1, either the rope 12 must slide on the pipe, or the pipe must carry the rope with it. But the rope cannot both slide on the pipe and drive the pipe by friction as the two things are not compatible: if the coeflicient of friction is so low that the rope slides on the pipe, it will not turn the pipe with suflicient force, and if the friction is such that the rope will turn the pipe against the various resistances, it will not slide on the pipe. Also obviously the pipe cannot carry the rope with it if the rope be an endless one and therefore of predetermined length. No endless rope drive or its quivalent will therefore work.

To meet these peculiar requirements the novel drive set forth here has been invented. In this drive (Fig. 3) the rope is given a reciprocating motion as by eccentric 44'which alternately pulls beam 43 up and then lets it come down. When beam 43 goes up it pulls up rope 42 attached to it and in doing so snubs the rope about the pi e and causes the latter to turn in the directlon of the arrow, as well as to move forward, i. e. to the right in Fig. 1, under the influence of guide 8, the rope being carried with the ipe to the right. This might cause trouble if the raise at 42 were such as to cause the pipe to make a full turn or more, but if it is such as to cause the pipe to turn through a small angle only (say under 180 deg., and preferable not more than deg.) the amount to which the r0 is carried with the pipe will not be su cient to cause trouble. On the downward stroke of the eccentric the rope unwinds itself under the action of the weight which is not sufficient even to keep the rope taut and the rope takes the original position except that it has been carried for a certain distance to the right with the pipe. There is however provided a wiper 46 is stationary and may be in the form of a ring or finger a ut the pipe and it does not (permit the rope to move to the right beyon a certain point. Not only that but if the pipe is moved to the right by some other means, it tends to sweep the ro e 12 to the left which it can do because at t at time the rope is not being pulled upwards by beam times there will be either one or two ropes loose and in a condition to be pushed back by them respective fingers (46, 47 or 50), whileat least one rope will be turning the pipe and moving it to the right.

Any engineer can devise a number of methods of driving the rope 12 to obtain the intermittent motion indicated here, as by eccentrics, cams, Geneva motions, etc. The horizontal beam 43 can be replaced by a vertical lever with a reciprocating motion, etc. The drive simply requires a series of coordinated short jerks following so closely upon each other as to provide what in practice amounts to a continuous drive, the driving element aftereach jerk being released and means being provided to assist it in returning to its original position with respect to the pipe structure.

It should be clearly borne in mind that the part of the pipe to which the rope drive is applied has already been welded, or that some other means is provided to convert it into a rigid structure. To understand the necessity of this, let us assume that roll 4 has been extended until it comes under ropes 12, 48 and 49, and that the pipe is not welded. The action of the rope will then wind the skelp tight around roll 4 and make it impossible for the skelp to move forward. On the other hand, if we insert into the skelp, between say 45 and 50, a loose cylinder of an external diameter equal say to the desired diameter of the pipe (internal), the rope will coil up about it and carry it with it. A better plan is however to have a piece of the skelp, say from 20 to 50, or roughlfitwo turns, welded first by some means, as e. g. hand welding. It is true of course that this iece may have to be thrown out later, but thls does not amount to much in a very long coil of skelp, particularly if the end of the first coil of skelp s welded to the beginning of the next one, as 1s common practice today.

As roll 4 does not have to support the pipe against the pull of the ropes, it can be made rather short, in fact just long enough to support the action of the welding disc 11. Either roll 3 or roll 4 may be insulated from each other, as by asbestos sleeve 51 and end washers 52. As the welding current is of very low voltage, the roblem of insulation is here quite simple. n the other hand, the rope drive may exert a powerful upward or downward pull, and if not properly taken care of, might produce a distortion in the pipe. To prevent this, bearings 53 and" 54 are provided. These bearings have to be of such a character as to permit free turning of the pipe and also its free motion to the right. To indicate this character of the bearings, they have been diagrammatically shown as casters. Depending on the size of the pipe, one, two or more sets may be needed.

While for the sake of clarity of description the driving element described here has been referred to, and shown in Fig. 3, as a rope,

Under certain conditions, e. g. where the.

surface of the skelp is not too smooth, a chain can be used instead of a rope. Finally, a magnet or magnets may be used to produce the equivalent of the frictional effect of the Another obvious substitution rope, and are therefore comprised under that term.

In the illustration, Fig. 1, the guide 8 is shown as part of mandrel 2 which is a convenient but not essentially necessary construction. The guide 8 has to be located within the seam 27 28, but it does not matter at all how it is supported, and e. g. itmight be suspended from some structure above the pipe. In Fig. l the guide and welding rolls lO'and 11 are shown at the top of the pipe. This seems to be the best location for these parts, largely because it permits to observe conveniently the action of the welding mechanism, but there is no basic reason why these parts should not be placed elsewhere.

While resistance welding has been referred to here, the apparatus set forth in this specification canbe applied to all forms of welding where a pressure in the seam is desired.

As shown in the drawing, Fig. 1, mandrel 2 is supported by an extension of shaft 1 which also carries the inside bending roll 31. The mandrel can be however executed as an integral part of shaft 9, or, indeed, may be omitted entirely, though at some sacrifice in convenlence.

As shown in Fig. 1, roll 4 extends only for a short distance from 20. If desired, it can extend as far as 45, and if it extends further, will cause binding. It would be possible of course to reduce its diameter slightly and then extend it as far as desired to the right, but the part beyond 45 cannot be the active part of the roll.

I claim:

1. A machine for forming sheet metal pipe comprising a mandrel, means for bending a metal strip to the form of a helix about said mandrel, a roll in substantial alignment w1th said mandrel but eccentric thereto and means for formin said helix about said roll.

2. A mac ine for forming sheet metal pipe comprising a mandrel of a diameter larger than that of the pipe to be formed, means for forming a helix of sheet metal and passing the same over the mandrel, aligned and spaced rolls of smaller diameter than the mandrel and means for re-formin the helix to substantially the diameter 0 a said aligned rolls on said rolls and means for welding the joint of the helix at the point where the joint passes between the aligned rolls, said rolls being electrically insulated from each other. 5 3. A machine for forming sheet metal pipe comprising a mandrel and two aligned spaced rolls in eccentric alignment with said mandrel and means for coiling a sheet metal strip first on said mandrel and then on said rolls.

4. A machine for forming spiral pipe comprising in combination forming rolls for bending a strip to the form of helix, a mandrel of substantially the diameter of the helix and over which the helix passes from the forming rolls, aguide associated with said mandrel and engageable with the helix to resist longitudinal movement thereof and means for bending said strip to a smaller radius as the helix passes from the mandrel to form a continuous pipe.

5. A machine for forming spiral pipe comprising in combination forming rolls for ending a strip to the form of a helix, a mandrel of substantially the diameter of the helix and over which the helix passes from the forming rolls, means associated with said mandrel and engageable with the helix to resist movement thereof longitudinally. of the mandrel, a roll of smaller diameter than the mandrel in alignment with said mandrel, one element of the roll being in alignment with an element of the mandrel, means for bending the helix to the diameter of the roll, and means for securing the adjacent edges of the helix to form a pipe.

6. A machine for formin spiral pipe comprising, in combination, forming rolls for bending a strip to the form of a helix, a

4 mandrel of substantially the diameter of the helix and over which the helix passes from the forming rolls, means associated with said mandrel and engageable with the helix to resist movement thereof longitudinally of the mandrel, a member of smaller diameter than the mandrel projecting therefrom and having its surface in one position forming substantially a continuation of the surface of the mandrel, means for bending the helix to a smaller diameter about said member as it passes from the mandrel, and means for securing together the edges of the helix.

7. machine for forming spiral pipe comprising, in combination, a mandrel of a diameter greater than that of the pipe to be formed, means for bending a strip to the form of a helix and for feeding said strip forward over the mandrel, a cylindrical member of smaller diameter than the mandrel projecting in substantial alignment with said mandrel in the direction of movement of the. helix and having one element of its surface in alignment with an element of the mandrel, means for bending the helix to a smaller diameter about said cylindrical member as the helix passes from the mandrel over said cylindrical member, and means for securing together the edges of the helix.

8. A machine for forming spiral pipe comprising, in combination, a mandrel of a diameter greater than that of the pipe to be formed, means for bending a strip to the form of a. helix and for feeding said strip forward over the mandrel, a cylindrical member of smaller diameter than the mandrel projcctin in substantial ali nment with said man rel in the direction 0 movement of the helix and having one element of its surface in alignment with an element of the mandrel, means for rotating the pipe being formed about said 0 lindrical member at a velocity sufficiently high relative to the velocity of the helix to draw said helix to a smaller diameter about the cylindrical member and to close the joint between successive turns with substantial pressure and means for permanently securing the joint.

Signed in New York, in the county and State of New York, this 2nd day of February, 1931.

LEON CAMMEN.

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