US3132616A

US3132616A - Spiral pipe producing apparatus

Info

Publication number: US3132616A
Application number: US86625A
Authority: US
Inventors: Gerald K Hale; Arthur W Hale; Reginald D Hale
Original assignee: BENTWORTH ENGINEERS NV
Current assignee: BENTWORTH ENGINEERS NV
Priority date: 1961-02-02
Filing date: 1961-02-02
Publication date: 1964-05-12
Anticipated expiration: 1981-05-12
Also published as: DE1452281A1; DE1452281B2; GB989106A; DE6607953U

Description

May 12, 1964 G. K. HALE ETAL SPIRAL PIPE PRODUCINC APPARATUS 5 Sheets-Sheet l Filed Feb. 2, 1961 nvvtwroks GERALD K. HALE ARTHURv W.

HALE

REGINALD D. HALE H TTURNEV May 12, -1964 G. K. HALE ETAL 3,132,616

SPIRAL PIPE PRoDucING APPARATUS Filed Peb. 2, 1961 5 sheets-sheet 2 .EJO

["fAoe les les /NVEA/Ta?! GERALD' K. HALE ARTHUR w. HALE REGINALD D. HALE y er l HTTORNEY! May 12, 1964 G. K. HALE ETAL SFIRAL PIPE PRODUCING APPARATUS 5 ...v e e h s Y 1 ...v nl e e h I... s 5 9. 0 2 u. nl--- .IL

4 4 2 I s m 9. L FM. s -------I I m l e a 9 .l 2 nv 2 6 6 l. .3 2

Filed Feb.

GERALD REGINALD D. HALE -f/ May Y12, 1964 G. K. H ALE ETAL lSPIRAI.. PIPE PRODUCING APPARATUS 5 Sheets-Sheet 4 Filed Feb 2 ARTHUR W. HALE REGINALD D. HALE May l2, Y1964 G. K. HALE ETAL 3,132,516

SPIRAL PIPE PRODUCING APPARATUS Filed Feb. 2, 1961 5 Sheets-Sheet 5 GERALD K. HALE l Q ARTHUR w. HALE REGINALD D. HALE E 72W l. T7-ORNE United States Patent O 3,132,616 sPIRaL Pire PRoDUCrNG APPARATUS Gerald K. Hale, Arthur W. Hale, and Reginald D. Hale,

This invention relates to apparatus for forming strong, fluid-tight spiral pipes from band stock.

An object of the present invention is the provision of apparatus for making spiral pipe and which may be quickly and easily adjusted to form pipes of different diameters by merely changing to a forming mandrel of suitable size but without the necessity of altering the forming dies of the apparatus.

Another object is the provision of spiral pipe forming apparatus which may be quickly changed to handle band stock of dilferent widths. i

Another objectis the provision of spiral pipe forming apparatus having a simple head for making a nal flange on one side of the band or strip stock, establishing a nal overlap between the incoming stock and the last complete convolution of the pipe in opposition to the flangeforming pressure, and making the final crimp in said overlap.

Still another object is the provision of apparatus of the nature described in which the crimping pressure and a spiral guide are utilized to draw the band stock into the apparatus and move the finished pipe outwardly therefrom.

Yet another Objectis the provision of apparatus for continuously forming spiral pipe and cutting said pipe normal `to the axis thereof without stopping the apparatus or the outward movement of the pipe.

A still further object is the provision of apparatus for forming spiral pipe having an exceedingly tight spiral seam therein which prevents the pipe from unwinding when subjected to a twisting action in a direction opposite to the spiral winding thereof.

Apparatus according to the present invention includes forming means for bending one edge of a stock band fed to the apparatus upwardly and the opposite edge thereof downwardly, forming means for crimping the stock longitudinally thereof, if such crimping is required7 means in opposition to each other for simultaneously` bending the upwardly-extending edge or flange inwardly and bending the downwardly-extending edge or llange inwardly beneath the upper flange of the last complete convolution of the baud stock around a mandrel, pressing or crimping the overlapped flanges together to form a fluidtight joint between the incoming band and the last convolution of the pipe, and means for cutting the pipe into desired lengths without stopping the apparatus or the outward movement of the finished pipe.

An example of this invention is illustrated in the accompanying drawings, in which:

FIGURE l is a plan View of apparatus for forming spiral pipe,

FIGURE 2 is a section taken on the line 2 2 of FIG- URE 1, showing the forming part of the apparatus in side elevation,

FIGURE 3 is a side elevation of the finished pipe and of the apparatus for cutting it into desired length,

FIGURE 4 is a cross section taken on the line 4 4 of FIGURE 3, x

FIGURES 5 to 9 inclusive are diagrammatic cross sections taken on the lines 5 5, 6 6, 7 7, 8 8, and 9 9, respectively, of FIGURE 2, illustrating in sequence the forming steps in the apparatus,

ICC

FIGURE l0 is a vertical fragmentary section taken on the line 10 10 of FIGURE 2,

AFIGURE 11 is a fragmentary section taken on the line 11 11 of FIGURE 2,

FIGURE 12 diagrammatically illustrates the various shapes of the band stock as it progresses through the different forming steps in the apparatus, and

FIGURE 13 is an enlarged cross section through a seam of the pipe.

Referring to the drawings, 10 is apparatus for forming spirally-wound pipe 11 from flat strip or band stock l2 drawn from a suitable source of supply, such as a roll 13. Apparatus 10 includes a suitable supporting frame 2l) having a platform 21 projecting from one side thereof. At least one open-ended forming box 24 is mounted on the side of supporting frame 20 opposite from platform 21 by any suitable means, such as bolts 25. Another open-ended forming box 27 may also be mounted by means of bolts 28 on frame 20 in line with box 24, and both of these boxes are in line with roll 13 mounted on a shaft 29 carried by suitable supports 31`and 32. A guide shelf 36 is mounted on box 24 and projects towards roll 13 so that the stock band 12 moves over said shelf into and through said box 24 and box 27, if the latter is used. Pairs of opposed

horizontal guide rollers

38 and 39 are mounted on shelf 36 and keep band 12 on a predetermined course.

A drum-like mandrel 42 is mounted on supporting frame 20 in any desired manner and extends outwardly therefrom at an angle inclined a little relative to a vertical plane extending at right angles to said frame, as clearly shown in FIGURE 1. This mandrel has an outer diameter corresponding substantially to the inner diameter of the pipe to be formed, and the angle of said mandrel to the direction of movement of incoming band 12, indicated by arrow 44 in FIGURE 1, determines the angle of the couvolutions of the band stock forming pipe 11. 1n this example, mandrel 42 has a bar 45 connected to and extending across its inner end, said bar being secured to frame 2t) by bolts 46 which extend through an appropriate pair of holes 47 in said frame.

The holes 47 are arranged in vertical spaced relation-V ship so as to be able to accommodate mandrels of different diameters.

The stock band 12 after being formed or shaped in

boxes

24 and 27 extends over and around the laterally inclined mandrel 42, and a spirally-arranged guide bar 2t) mounted on and extending almost completely around mandrel42 imparts a lateral component to the stock to move pipe 11 outwardly relative to supporting frame 20. Guide bar S0 has a commencing end 51 at the top of the mandrel and a finishing end 52 on said top but spaced circumferentially and laterally from end 51, see FIGURE l.

Forming box 24 includes means for bending one edge of band 12 upwardly and the opposite edge thereof downwardly in either one or two stages. There may be several of these forming boxes for shaping bands of different widths, and the selected box is mounted on supporting frame 20 by bolts 25. In this example of the apparatus, the strip or band is shaped in two steps. Box 24 includes upper and lower forming rolls 56 and 57 between which band 12 travels. Rolls 56 and 57 are correspondingly shaped at one end at 59 to incline edge 60 of band 12 upwardly, and the rolls are formed at their opposite ends at 62 to incline the opposite edge 63 of the band downwardly and outwardly. Either or both of these rolls is or are driven. Roll 56 is fxedly mounted on a shaft 66 which is journalled in bearing 67 in support 2i), said bearing being carried by a horizontal pin 68 so that it will allow shaft 66 to be swung up and down to a limited degree. The opposite end of shaft 66 is journalled in a bearing 70 mounted for vertical movement on the lower end of a spindle 71 threaded in a Wall of box 24, said spindle having a wheel 72 on its upper end. Rotation of this wheel in either direction raises or lowers the end of shaft 66 carried by bearing 70. Roll- 57 is xedly mounted on a shaft 75 suitably journalled in frame 2t) and the opposite wall of box 24, see FIGURE 5. A gear 7.7 lixed on shaft 66 meshes with another gear 73 lixedly mounted on shaft 75. The overlap of the teeth of these two gears is suficient to permit the vertical swinging movement of shaft 66 referred to above.

Another pair of forming

rolls

80 and 81 are lixedly mounted respectively on shafts 82 and 33 journalled in frame and the wall of box 24 in the same manner as shaft 75. These rolls are correspondingly shaped at the opposite ends thereof to bend edges or

flanges

60 and 63 upwardly anddownwardly, respectively, substantially at right angles to the general plane of band 12. FIGURE 6 illustrates the manner in which edge or flange 63 is bent downwardly. Either or both of

shafts

82 and 83 may be driven, or they may be idler shafts, as shown.

Forming box 27 is used only when it is desired to crimp band 12 longitudinally thereof for stitfening purposes. In this example, box 27 contains a pair of forming

rolls

86 and 87 fixedly mounted on

shafts

88 and 89. Roll S6 has one or more annular grooves 91 formed in the surface thereof, while roll 87 has a corresponding number of annular ribs 92 on its surface, each rib tting into a groove 91 of roll 86. FIGURE 7 illustrates two grooverib arrangements and when band 12 passes between these rolls, two longitudinal crimps or ribs 94 are formed therein. These may be the linal ribs or crimps for the stock, but if the ribs are to project relatively far from the surface of the band stock, a second pair of forming

rolls

98 and 99 are iixedly mounted on

shafts

100 and 101 within box 27. These rolls have the same number of grooves and ribs thereon as rolls S6 and 87, but the `grooves are deeper and the ribs higher. FIGURE 8 illustrates one of the grooves 104 in roll 93, and one of the ribs 105 on roll 99. Any or all of the

shafts

88, 89, 166 and 101 of forming box 27 may be driven, or they may not have any driving connection so that the rolls mounted thereon are idler rolls, as shown.

As band 12 leaves the forming boxes, it travels over and around the surface of mandrel 42. For the sake of clarity, the portion of band 12 passing over the top of the mandrel is designated 12a, while the portion of said band forming the last complete convolution of pipe 11 is designated 12b.

A forming unit 163 is positioned at the top of mandrel 42 so that band 12u passes therethrough. Unit 1118 includes a horizontal support 110 cairied by and projecting outwardly from supporting frame 20 spaced above mandrel 42. A horizontal plate 112 is mounted for vertical movement in suitable guides 113 depending from support 108, said plate being carried by a threaded spindle 115 threaded through support 108 and having a wheel 116 on the upper end thereof by means of which plate 112 may be raised and lowered. Suitable lugs 118 hang down from plate 115 and carry a shaft 120 which extends freely through support 20 and is journalled in a bearing 122 mounted for verticalswinging movement in a bracket 123 projecting upwardly from platform 21. A crimping roll 126 is lixedly mounted on shaft 120 beneath plate 112 and cooperates with a lower crimping roll 127 fixedly mounted on a shaft 128 carried by lugs 129 supported within mandrel 42 beneath the upper surface thereof. Said mandrel is provided with an opening 132 at this point through which lower roll 127 projects, see FIGURE 2.

Rolls

126 and 127 have

coacting crimping heads

135 and 136 at one end thereof. These crimping heads preferably have knurled surfaces, as shown in FIGURE 10. Furthermore, when an absolutely tight pipe is required, a narrow indenting annular rib 137 is provided on and 'er projects outwardly from the surface of head 135. Roll 126 is formed with grooves y138 therein to permit ribs or beads 94 of strip 12a to pass therethrough. The latter roll also has a bevelled guide disc 139 on its opposite end.

A pair of horizontal bevelled rollers and 146 are located at the opposite edges of strip 12a just ahead of crimping rolls 126-127. These rollers are mounted in any desired manner. For example,

rollers

145 and 146 are rotatably mounted on the lower ends of

rods

148 and 149 which hang down from plate 112. Roller 145 is bevelled downwardly so that it bears against edge or liange 60 of band 12a to incline said edge or ange inwardly relative to the band stock. Roller 146 is bevelled upwardly opposite to roller 145, and it is located 1mmediately above band 12b. As band 12a approaches forming unit 108, it overlaps band 12b of the last convolution of the pipe so that flange 63 is over band 12b near flange 60 of the latter, said flanges being in lapped relationship. Roller 146 inclines flange 63 inwardly of band 12a so that it lits beneath flange 60 of band 12b, as clearly shown in FIGURE 9. With this arrangement, the operating pressures of

rollers

145 and 146 are directly opposed to each other. In order to prevent band 12a from bending upwardly under this opposed lateral pressure, a pressure roller is provided at the upper surface of said band, said pressure roller being carried by an arm 156 supported by vertical rod 148. It will be noted that the axis of roller 155 extends across but is spaced above band 12a so that the roller actually rolls over said band during movement of the latter.

Roller 146 is just ahead of crimping

heads

135 and 136, and when the lapped

flanges

63 and 60 of

bands

12a and 12b pass between said crimping heads, said bands are pressed over the lapped lianges, and the assembly is pressed together to form a crimped joint 160 which is actually the joint between incoming band 12a and the preceding convolution of the band 12b. The indenting rib 137 of head 135 bites into the top of joint or seam 160 to deform the material into a narrow longitudinal depression 161 to form an absolutely tight joint, see FIGURE 13. The full pressure of head 135 is concentrated on the narrow rib 137 so that the various layers of seam 160 at depression 161 become almost amalgamated under said rib. This crimped joint 160 extends in a spiral throughout the pipe, as clearly shown in FIG- URE 1.

A spring-loaded pressure roller 164 is mounted immediately behind unit 108 in order to give a downward component to the shaped band 12a as the edge 6) thereof approaches guide bar 50. This guide bar is formed with an undercut shoulder 166 in order to accommodate the inwardly inclined edge or ange 6) of band 12a, see FIGURE 11. As bar 50 winds in a spiral around man drel 42, it ensures strip 12a following the proper course around the mandrel to bring ange 60 of band 12b up beneath flange 63 of the incoming strip 12a. The crimping

heads

135 and 136, being driven, provide the force which draws band 12a on to the mandrel, rotates pipe 12 around said mandrel and drives the incoming band against guide bar 50 which imparts a lateral component to pipe 11.

Pressure roller 164 is mounted in any desired manner. In this example, it is carried by a yoke 168 mounted on the lower end of a pin 169 whichslidably extends through a lug 170 projecting laterally from and carried by supporting frame 20. A spring 171 on rod 169 between lug 170 and yoke 168 exerts a downward pressure on roller 164.

The power for operating apparatus 10 is provided by a suitable source, such as an electric motor 175 mounted on platform 21. A sprocket 176 mounted on the motor shaft is connected by a chain 177 to another sprocket 178 lixedly mounted on an extension of shaft 120 of upper crimping roll 126. A gear 181 fixed on said shaft meshes with another gear 182 tixedly mounted on shaft 128 of lower crimping roll 127. With this arrangement, motor 175 drives both of the crimping

rolls

126 and 127. A sprocket 186 is fxedly mounted on shaft 120 and is connected by a chain 187 to another sprocket 188 xedly mounted on shaft 75 of forming roll 57. Thus, motor 175 drives forming rolls 56 and 57. 1f desired, forming rolls 80-81, 86-87, and 98-99 may be driven in the same manner by motor 175, or they may be driven from either of the

shafts

66 or 75.

FIGURE 12 diagrammatically illustrates the forming steps to which band 12 is subjected. At A edges 60 and 63 of the band are inclined upwardly and downwardly as a result of action by rolls 56 and 57, and at B said sides or flanges are extending straight up and straight down having passed through

rolls

80 and 81. At C longitudinal crimps or ribs 99 have been put into the band by rolls 86--87 and 98-99. At D flange 60 has been inclined inwardly while flange 63 of band 12a has been lapped with flange 60 of band 12b by

rollers

145 and 146, after which the crimped joint 160 has been formed by crimping

heads

135 and 136. f

The` outside `diameter of mandrel 42 determines the inside diameter of the finished pipe 11. If it is desired to make a pipe of a different diameter, a mandrel of the desired diameter is mounted on supporting frame 20. If the width of band stock 12 is changed, it is necessary to change

rolls

126 and 127 or forming unit 108, forming box 24 and forming box 27, if the latter is used, to accommodate the band of the new width. In either change, the angle of mandrel 42 to frame 20 has to be suitable for thenew diameter of pipe or width of band stock.

Pipe 11 may be any desired length. Apparatus 10 includes a cutting section 200 by means of which pipe of any desired length may be cut off from the pipe being formed on the mandrel. This cutting section is clearly illustrated in FIGURES l, 3 and 4.

Cutting section 200 includes a carriage 204 mounted for movement parallel with pipe 11 on suitable track means. In this example, carriage 204 is provided with rollers 206 which ride in tracks or grooves 207 on a platform 208, said platform being carried by a horizontal axle 209 supported` by lugs 210 projecting upwardly from a base 211. Axle 209 extends parallel to pipe 11 so that platform 208, and, consequently, carriage 204 may be tipped downwardly towards said pipe, these elements being normally tipped away therefrom by a suitable counterweight 215 connected to carriage 204. A circular saw 218 is ixedly mounted on a shaft 219 which is journalled in suitable bearings 220 carried by a portion 221 of carriage 204 extending over but spaced from the top of pipe 11. This saw and its shaft are rotatedV by means of a suitable source of power, such as an electric motor 224 mounted on table 204. A pulley 225 is mounted on the shaft of the motor and is connected by belt 226 to another pulley 227 fixedly mounted on shaft 219. A handle 230 is connected to table 204 and extends outwardly over pipe 11. The edge of the table may be depressed by means of handle 230 to cause saw 218 to cut into pipe 11 therebeneath.

As pipe 11 is moving continuously, it is necessary to cause saw 218 to move at exactly the same speed and in the same direction as the pipe. This is accomplished by means of a clamping ring 235 which surrounds pipe 11 and normally slips along said pipe. Ring 235 is split at 236, and the

ends

237 and 238 of said ring are drawn together or moved apart by a suitable clamp 240 which is connected to said ends. This is a known type of clamp, and it has a handle 241 which when moved in one direction causes ring ends 237 and 238 to be separated, and when the handle is moved in the opposite direction, said ends are drawn together firmly to clamp the ring on pipe 11. An annular flange 245 surrounds ring 235 and slidably lits into a plurality of U-shaped lugs 247 xedly mounted on said ring. This arrangement allows clamping ring 235 to contract and expand under the action of clamp 240 without being separated from said flange. In other words, flange 245 moves with clamping ring 235 but is not fixedly secured thereto.

An arm 242 extends from carriage 204 and has a roller 243 on its outer end which bears against llange 245. With this arrangement, when ring 235 is clamped to pipe 11 and moves with it, flange 245 moves in the same direction, said direction being indicated by arrow 244 in FIGURE l, and this ring causes carriage 204, through roller 243 and arm 242, to move in the same direction. At this time, handle 230 is depressed by an operator to cause blade 218 to cut into pipe 11. As this pipe is rotating around its longitudinal axis and the saw is moving with the pipe, a cut is made completely around the pipe to sever the outer portion thereof from that still supported by mandrel 42. A suitable stop 246 is provided on platform 208 to limit the outward movement of carriage 204 along said platform. Saw 218 must be lifted clear of the pipe before the carriage engages this stop, and clamp 240 must be operated to release ring 235 from the pipe. When it is desired to cut the pipe again, ring 235 is moved back along the pipe and then clamped thereto at the desired point. After this, carriage 204 is moved counter to the movement of the pipe until roller 243 engages flange 245, at which time the carriage may be depressed to make another cut in the pipe.

The pipe 11 being produced may be supported in any convenient manner. 011e way of doing this is to provide a plurality 'of rollers 250 beneath the pipe on opposite sides of the bottom thereof, each roller 250 being mounted on the upper end of the rod 251 which extends through a sleeve 252 carried by a base 253. A set screw 254 retains each rod 251 in its sleeve 252 in any adjusted position. Rollers 250 are angled relative to the pipe radius in order that they travel along the spiral band 12b between seams 160.

Apparatus 10 may be used with band stock of dilferent widths and to form pipes of different diameters. The pipe diameter may be changed merely by replacing the mandrel but without changing or adjusting any of the forming elements. Each mandrel has its own setting or angle relative to the supporting frame 20. If it is desired to change the width of the band stock, forming

boxes

24 and 27, and forming unit 108 or rolls 126 and 127 thereof have to be changed to acocmmodate the new width. A mandrel 42 having the correct angle to frame 20 for the new width would have to be used. The crimping heads forming the final seam provide the power for rotating the pipe around the mandrel and outwardly therefrom. These heads also form the narrow longitudinal depression in the seam which makes a fluid-tight joint and prevents the spiral band of the pipe from unwinding or slipping along the seam when the pipe is subjected to a twisting action in a direction opposite to the spiral winding thereof. Cutting section 200 is used to sever desired lengths from the pipe being formed without slowing down or stopping the operation of the apparatus.

What we claim as our invention is:

1. Apparatus for forming a spiral pipe comprising a supporting frame, a pair of upper and lower pressure rolls mounted on parallel shafts supported by and projecting outwardly from said frame, at least one of said pressure rolls being driveable, a stationary cylindrical mandrel supported at one end thereof by the frame near the rolls and extending outwardly from said frame, the longitudinal axis of the mandrel extending generally in the same direction as the roll shafts but inclined relative to said shafts, said mandrel having an opening therein near the support, the lower roll being positioned within the mandrel at said opening thereof and the upper roll being positioned outside the mandrel, said rolls forming a pressure nip therebetween substantially on the circle formed by the circumference of the mandrel and the surface of said mandrel extending from near one side ofthe lower roll to near the opposite side thereof, means for guiding a stock band with one side edge inclined upwardly and inwardly and the opposite side edge thereof bent downwardly as an upper portion into the nip of the pressure rolls in direction substantially normal to the roll shafts, means outside the mandrel for directing the stock band from the rolls around the outer surface of the mandrel, said band extending around the mandrel as a lower portion beneath said upper portion with the down edge of the upper portion over and bent beneath to lap the inwardly-inclined upper edge of the lower portion at a point between the pressure rolls, pressure applying means to bias the rolls together to apply pressure to the lapped edges only at said point so that the lapped edges of the stock band pass only once through the nip of said rolls at said point to draw the stock band therebetween and to draw the lower portion of the band around the mandrel and press the lapped edges of the upper and lower portions together to form a seam and thereby a spiral pipe on the mandrel, the size of the mandrel and the angle thereof to the roll shafts above determining the inner diameter of the formed pipe so that pipes of different diameters may be made from the same stock band merely by changing the mandrel and the angle thereof relative to the pressure roll axes.

2. Apparatus as claimed in claim 1 including a downwardly-bevelled horizontal roller positioned to bear against the up side edge of the upper portion of the band immediately ahead of the pressure rolls with reference to the direction of movement of said upper portion, and an upWardly-bevelled horizontal roller directly opposed to said downwardly-bevelled roller and over said lower portion and positioned to press the down edge of the upper portion of the band inwardly of said upper portion and beneath and lapping said inclined edge of the lower portion, said upwardly-bevelled roller being positioned to exert a force against the down edge in opposition to that of the downwardly-bevelled horizontal roller against the up edge.

3. Apparatus as claimed in claim 1 wherein one of said pressure rolls has a circumferential rib cooperable with the opposed pressure roll to form said point in the nip of said rolls where pressure is applied to said lapped edges.

4. Apparatus as claimed in claim 1 including a spiral guide at the mandrel surface at and bearing against the up bent edge of said upper portion of the band to impart a lateral component to said upper portion to move the formed pipe along the mandrel in a direction away from the pressure rolls during movement of said pipe around the mandrel.

5. Apparatus as claimed in claim 4 in which an edge of the spiral guide is undercut to accommodate the inwardly-inclined up edge of the upper portion of the band being directed to the mandrel.

6. Apparatus for forming a spiral pipe comprising a supporting frame, a pair of upper and lower pressure rolls mounted on parallel shafts supported by and projecting outwardly from said frame, a stationary cylindrical mandrel supported at one end thereof by the frame near the rolls and extending outwardly from said frame, the longitudinal axis of the mandrel extending generally in the same direction as the roll shafts but inclined relative to said shafts, said mandrel having an opening therein near the support, the lower roll being positioned within the mandrel at said opening thereof and the upper roll being positioned outside the mandrel, said rolls forming a pressure nip therebetween substantially on the circle formed by the circumference of the mandrel and the surface of said mandrel extending from near one side of the lower roll to near the opposite side thereof, means for guiding a stock band with one side edge inclined upwardly and inwardly and the opposite side edge thereof bent downwardly as an upper portion into the nip of the pressure rolls in a direction substantially normal to the roll shafts, means outside the mandrel for directing the stock band from the rolls around the outer surface of the mandrel, said band extending around the mandrel as a lower portion beneath said upper portion with the down edge of the upper portion over and bent beneath to lap the inwardlyinclined upper edge of the lower portion at a point between the pressure rolls, pressure applying means to bias the rolls together to apply pressure to the lapped edges only at said point so that the lapped edges of the stock band pass only once through the nip of said rolls at said point to draw the stock band therebetween and to draw the lower portion of the band around the mandrel and press the lapped edges of the upper and lower portions together to form a seam and thereby a spiral pipe on the mandrel, the size of the mandrel and the angle thereof to the roll shafts above determining the inner diameter of the formed pipe so that pipes of different diameters may be made from the same stock band merely by changing the mandrel and the angle thereof relative to the pressure roll axes, track means extending parallel to the direction of movement of the pipe, a carriage mounted for movement along the track means and extending over the pipe, said carriage being mounted for movement towards and away from the pipe, cutting means carried by the carriage for cutting the pipe across the axis thereof, clamping means for the pipe to be secured to said pipe to move therewith, and means connecting the clamping means to the carriage to cause the latter to move with the pipe when said clamping means is secured thereto.

References Cited in the le of this patent UNITED STATES PATENTS 128,911 Ritchie July 9, 1872 519,182 Gould May 1, 1894 628,643 Abrahams July 11, 1899 1,238,986 Colby Sept. 4, 1917 1,394,116 Rendano Oct. 18, 1921 2,136,943 Freeze Nov. 15, 1938 2,282,176 Fay et al May 5, 1942 2,339,219 Crowley Jan. 11, 1944 2,862,469 Jensen Dec. 2, 1958 FOREIGN PATENTS 1,056,320 France Oct. 21, 1953 1,197,896 France lune 8, 1959

Claims

1. APPARATUS FOR FORMING A SPIRAL PIPE COMPRISING A SUPPORTING FRAME, A PAIR OF UPPER AND LOWER PRESSURE ROLLS MOUNTED ON PARALLEL SHAFTS SUPPORTED BY AND PROJECTING OUTWARDLY FROM SAID FRAME, AT LEAST ONE OF SAID PRESSURE ROLLS BEING DRIVEABLE, A STATIONARY CYLINDRICAL MANDREL SUPPORTED AT ONE END THEREOF BY THE FRAME NEAR THE ROLLS AND EXTENDING OUTWARDLY FROM SAID FRAME, THE LONGITUDINAL AXIS OF THE MANDREL EXTENDING GENERALLY IN THE SAME DIRECTION AS THE ROLL SHAFTS BUT INCLINED RELATIVE TO SAID SHAFTS, SAID MANDREL HAVING AN OPENING THEREIN NEAR THE SUPPORT, THE LOWER ROLL BEING POSITIONED WITHIN THE MANDREL AT SAID OPENING THEREOF AND THE UPPER ROLL BEING POSITIONED OUTSIDE THE MANDREL, SAID ROLLS FORMING A PRESSURE NIP THEREBETWEEN SUBSTANTIALLY ON THE CIRCLE FORMED BY THE CIRCUMFERENCE OF THE MANDREL AND THE SURFACE OF SAID MANDREL EXTENDING FROM NEAR ONE SIDE OF THE LOWER ROLL TO NEAR THE OPPOSITE SIDE THEREOF, MEANS FOR GUIDING A STOCK BAND WITH ONE SIDE EDGE INCLINED UPWARDLY AND INWARDLY AND THE OPPOSITE SIDE EDGE THEREOF BENT DOWNWARDLY AS AN UPPER PORTION INTO THE NIP OF THE PRESSURE ROLLS IN A DIRECTION SUBSTANTIALLY NORMAL TO THE ROLL SHAFTS, MEANS OUTSIDE THE MANDREL FOR DIRECTING THE STOCK BAND FROM THE ROLLS AROUND THE OUTER SURFACE OF THE MANDREL, SAID BAND EXEXTENDING AROUND THE MANDREL AS A LOWER PORTION BENEATH SAID UPPER PORTION WITH THE DOWN EDGE OF THE UPPER PORTION OVER AND BENT BENEATH TO LAP THE INWARDLY-INCLINED