EP0104844A2

EP0104844A2 - Apparatus for manufacturing flexible corrugated tubes

Info

Publication number: EP0104844A2
Application number: EP83305425A
Authority: EP
Inventors: Gunter Schafer
Original assignee: Security Lumber and Supply Co
Current assignee: Security Lumber and Supply Co
Priority date: 1982-09-28
Filing date: 1983-09-15
Publication date: 1984-04-04
Also published as: DE3372446D1; EP0104844B1; EP0104844A3; CA1231006A; DK445083A; DK445083D0; ES525975A0; ES8502356A1

Abstract

Apparatus for helically curling longitudinally currugated thin strip material into a flexible corrugated tube has a curling unit with driven input rollers forming a nip that matches the strip, and a cassette for a reel of the material which is connected to said unit and has strip guide rollers immediately adjacent the input rollers. The curling unit has driven output rollers on an upright support to drive the strip, and a spider which is vertically adjustable on the support and carries strip guide rollers which are on spindles equidistant from the longitudinal axis of the forming tube, and radially adjustable, so that adjustment of the spider on the support and the spindles on the spider permits the unit to form tubes of different diameters. A locking mechanism intermittently crimps overlapping parts of the forming tube. A bending device aids in forming relatively stiff strip stock, and also aids in forming softer stock into very small diameter tubes.

Description

The present invention relates to an improved apparatus for forming a longitudinally corrugated thin strip into a flexible corrugated tube generally like that disclosed in U.S. Patent 4,141,385, issued February 27, 1979 to Emil Siegwart.
The prior art apparatus known to applicant which is the most closely related to the present apparatus is that of U.S. Patent 4,058,997, issued November 22, 1977 to Emil Siegwart.
Apparatus of the type disclosed in U.S. Patent 4,058,997 may be used to produce tubes of different diameters only by removing from the apparatus a plate which carries a circle of forming rollers which are tangent to a circle of one diameter, and replacing that plate with another one which carries rollers that are tangent to a circle of a different diameter. As a result, switching the machine from the manufacture of a tube of one diameter to that of another diameter is quite a complex and time consuming job.
A large percentage of the flexible corrugated tubes made in this type of machine are used for air conditioning ducts, and any particular air conditioning installation usually requires ducts in several different sizes. Ideally, a portable duct curling machine is used to produce duct as needed at a job site, and there are portable units for this purpose. However, the portable units, like the unit of the Siegwart patent, may be used to produce tubes of different sizes only by replacing an entire front plate which carries the curling rollers that are tangent to a circle of a particular diameter. This means that several interchangeable curling die plates must be carried with the portable machine.
The apparatus of patent 4,058,997 has a mechanism illustrated in Fig. 5 of the drawings for forming in overlapping turns of the helical tube a lock of the type illustrated in patent 4,141,385. Such a lock has certain disadvantages which can be eliminated by a lock of a different type.
Finally, portable apparatus of a type heretofore developed by the present inventor in Germany utilizes a cassette to receive a reel of precorrugated strip which is used in the fabrication of the flexible corrugated tube.
In accordance with the present invention, a portable apparatus for manufacturing flexible corrugated tube includes a cassette to receive a reel of longitudinally corrugated strip, and an outfeed opening of the cassette is provided with a pair of guide rollers which have intermeshing arcuate lands and grooves forming a nip that matches the corrugations of the strip, and when the cassette is hung on the frame of the curling apparatus, the nip of the guide rollers is immediately adjacent and coplanar with the nip of driven infeed rollers which also exactly match the corrugations of the strip. Accordingly, the feed of the strip into the curling apparatus is carefully controlled, and any deviations in the corrugations or possible deformations in the edges of the strip are eliminated before the strip enters the curling rollers.
Further, the rollers which are arranged in a circle to determine the diameter of the tube being produced by the apparatus are carried upon a spider which is vertically adjustable relative to strip outfeed rollers that drive the strip into the circular array of curling rollers. The spider is movable vertically relative to the outfeed rollers so as to change the distance from the nip of the outfeed rollers to the longitudinal axis about which the curling die rollers form a circle, and at the same time all of the curling die rollers are radially adjustable with reference to that axis so as to permit the apparatus to be very simply adjusted to produce tubes of different diameters.
In the preferred embodiment described, a single manual adjusting crank serves to move the spider vertically relative to the nip of the outfeed rollers, and at the same time moves all of the curling die rollers radially to accomplish the desired adjustment of diameter in a single operation.
The apparatus of the present invention may be readily adjusted to produce corrugated tube from about .50.8 mm (2 inches) to about 508mm (20 inches) in diameter.
The coil locking apparatus of the present invention has jaws which indent the two sides of a corrugation, rather than squashing the top of the corrugation as taught in patent 4,141,385. The resulting lock is less obtrusive and thus produces a better looking tube than the prior art.

_Fig. 1 is a schematic perspective view of the present curling apparatus to show the relationship between the curling unit and the cassette, parts being omitted for clarity;
_Fig. 2 is a fragmentary view of a part of a corrugated strip curled into a segment of a tube;
_Fig. 3 is a front elevational view of the curling apparatus of the invention with parts broken away for clarity and with only the immediately adjacent part of the cassette illustrated;
Fig. 3A is a fragmentary sectional view on an enlarged scale taken substantially as indicated along the line 3A-3A of Fig. 3;
Fig. 4 is a fragmentary sectional view on an enlarged scale, with parts broken away, taken substantially as indicated along the line 4-4 of Fig. 3;
Fig. 5 is a fragmentary sectional view taken substantially as indicated along the line 5-5 of Fig. 4;
_Fig. 6 is a fragmentary sectional view taken substantially as indicated along the line 6-6 of _Fig. 3;
_Fig. 7 is a fragmentary sectional view taken substantially as indicated along the line 7-7 of Fig. 4;
Fig. 8 is a fragmentary sectional view on an enlarged scale, taken substantially as indicated along the line 8-8 of Fig. 4, illustrating the coil locking mechanism of the present apparatus;
Fig. 9 is a fragmentary sectional view on an enlarged scale, taken substantially as indicated along the line 9-9 of Fig. 8;
Fig. 10 is a fragmentary section on an enlarged scale taken substantially as indicated along the line 10-10 of Fig. 8;
Fig. 11 is a fragmentary schematic view of the curling die rollers and the forming strip;
Fig. 12 is a diagramatic view illustrating the relative positions of the curling die rollers with respect to the outfeed rollers and one another in two different adjusted positions of the spider;
Fig. 13 is a fragmentary elevational view, which is partially schematic, illustrating a bending device in detail, and showing the curling unit adjusted to form a tube of very small diameter; and
Fig. 14 is a fragmentary sectional view taken substantially as indicated along the line 14-14 of Fig. 13.

Referring to the drawings in detail, and referring first to Figs. 1-3, a tube forming apparatus, indicated generally at 18, includes a curling unit, indicated generally at 20 and a cassette 21 from which the unit 20 receives precorrugated aluminum strip S to form into flexible tube T.
The tube forming apparatus 20 has a base 22 that includes a frame 23, and cooperating input rollers 24 and 25 are mounted on the frame to feed the precorrugated strips S recieved from the cassette 21.
The curling die unit 20 also includes an upright support 26 which has a base plate 26A that is rotatable on the base 22 on a vertical axis as will be described in more detail; and output rollers 27 and 28 are carried upon the support 26 to receive the strip S from the input rollers 24 and 25 and feed it into a bending device 119 (detailed in Fig. 13), and a series of curling die rollers 29-35 which are journaled on respective spindles 29A-35A that are mounted in a circular configuration on a curling die base 36 that is vertically adjustable on the upright support 26. The spindles 29A-35A are readily removed.
The curling die base 36 includes a roller supporting spider 37, a frame 38 and guide posts 38A that are guided in sleeves 39 which are mounted on a cross bar 40 on the rear of a gear housing 41 that is fixed on the upright support 26. The radial distance of each of the rollers 29-35 form a center 37A of the roller supporting spider 37, which coincides with the longitudinal axis of a forming tube T, may be adjusted so as to allow the manufacture of flexible tubes having different diamters. Furthermore, when the radial distance of the rollers 29-35 from the center 37A is changed, the spider 36 and the rollers 29-35 are moved vertically on the support 26 toward or away from the output rollers 27 and 28 so that the center 37A of the spider 37 always coincides with the longitudinal axis of the flexible tube being formed. During this vertical adjustment of the spider, the support 26 is rotated on the base 22 about its vertical axis, so the angle of the helix formed by spiral winding the corrugated strip _S matches the diameter of the forming tube T. A small tube requires a large helix angle, while a large tube requires a small helix angle.
Referring especially to Figs. 4-7, the vertical adjustment of the curling die base 36 and the radial adjustment of the rollers 29-35 are both accomplished by using a hand crank 42 to turn a spindle 43 which carries an adjusting bevel drive gear 44 that drives a cluster of bevel pinions 45-52 (see Fig. 7).
The bevel pinion 45 is attached to the upper end of an upright adjusting screw 53 which extends within a screw housing 54 of the curling die base 36 and is vertically movable through a threaded nut 55 which is disposed within the housing 54 and is part of a block that extends outwardly through an elongate opening of the housing 54 and is mounted upon the gear housing 41. Rotation of the spindle 43 causes a corresponding rotation of the upright screw 53 .within the nut 55, and this causes the entire curling die base 36 to move vertically with respect to the output rollers 27-28 which are carried on the gear housing 41.
Secured to the frame 38 is a cam plate 56 that includes a cam slot 57 which traverses a cam follower 58 that is fixedly secured to the base 22. Vertical movement of the curling die base 36 causes the cam slot 57 to traverse the cam follower 58, and this causes the upright support 26 to rotate about its axis, which is the axis of a vertical shaft 59 that is bearing supported within the base 22. A base plate locking bolt 26B extends through an arcuate slot 26C in the base plate 26A of the upright support 26, and the locking bolt 26B is loosened when the tube diameter is to be changed. The pivotal movement of the parts changes the angle of the helix to match the diameter of the tube being formed, and the amount of the pivotal movement is controlled by the shape of the cam slot 57.
As seen in Fig. 7, the pinions 46-52 are part of spindle adjusting means 60 for adjusting the radial positions of the curling die roller spindles 29A-35A. The pinions 46-52 are mounted on respective radial adjusting screws 61-67 that are carried within radial screw housings 68-74 of the spider 37. The radial adjusting screws 61-67 engage respective spindle nuts 75-81 which are parts of slide blocks on which the spindles 29A-35A are respectively mounted. Therefore, all the curling die rollers 29-35 move radially in unison toward or away from the center 37A of the roller spindle 37 in response to rotation of the spindle 43.
Thus, the following three actions occur when the spindle 43.is rotated:

1. The center 37A of the spider 37 moves.vertically toward or away from the output rollers 27-28, which remain stationary;
2. Each of the rollers 29-35 moves in a radial direction relative to the center 37A; and
3. The upright support 26 rotates about the axis of the vertical shaft 59 to change the helix angle.

As best seen in Figs. 3 and 4, a motor 82 is mounted upon the base 22 and is connected through a timing belt drive 83 to the upright shaft 59. The shaft 59 is coupled via bevel gears 84-85 and a timing belt drive 86 to a lower output shaft 27A which mounts the lower output roller 27. The lower output shaft 27A is also coupled through gears 87-88 to an upper output shaft 28A which mounts the upper output roller 28.
Referring also to Fig. 6, the input rollers 24-25 are driven by means of a second timing belt drive 89 from the upright shaft 59 to a shaft 90. A bevel gear 91 on the shaft 90 meshes with a bevel gear 92 on a jack shaft 93 to drive a further timing belt drive 94 for a lower input roller 24A which mounts the lower input roller 24. The lower input roller shaft 24A, in turn, is connected by gears 95 and 96 to an upper input roller shaft 25A which mounts the upper input roller 25.
Referring also to Fig. 6, the input rollers 24-25 are driven by means of a second timing belt drive 89 from the upright shaft 59 to a shaft 90. A bevel gear 91 on the shaft 90 meshes with a bevel gear 92 on a jack shaft 93 to drive a further timing belt drive 94 for a lower input roller 24A which mounts the lower input roller 24. The lower input roller shaft 24A, in turn, is connected by gears 95 and 96 to an upper input roller shaft 25A which mounts the upper input roller 25.
Referring now to Fig. 1, the cassette 21 has a frame, indicated generally at 97, with a plurality of sides including a rear side 98, lateral sides 99 and 100, and a front side 101. A spindle 102 is mounted on the rear side 98, there is a strip outfeed opening 99A in the lateral side 99, and the front side 101 consists of a pair of doors 103 on hinges 104 mounted on the lateral sides 99 and 100. The spindle 102 receives a reel 105 of the corrugated strip S.
Upper mounting brackets 106 and lower brackets 107 detachably connect the cassette 21 to the frame 23 of the curling unit 20, with the strip outfeed opening 99A immediately adjacent the input rollers 24 and 25. In the opening 99A is a pair of strip guide rollers 108-l09 which have a nip coplanar with that of the input rollers 24 and 25 when the cassette is mounted upon the curling frame 23.
When a new reel 105 of corrugated strip S is mounted in the cassette, the end of the strip must be guided through the nip of the guide rollers 108-109, through the nip of the input rollers 24-25, and through the nip of the output rollers 27-28. The end of the strip is then fed into tangency with the curling die roller 99, or alternatively to the inner side of a bending roller if that is used, as hereinafter described.
As the corrugated strip S is removed from the reel 105, the guide rollers 108-109 assure that it will be properly fed into the infeed rollers 24-25 as the outer diameter of the strip remaining on the reel decreases. When the supply of strip on a reel 105 is exhausted, the front doors 103 are opened, the exhausted reel is removed and a full reel is placed on the spindle 102, and the new strip is threaded through the guide rollers 108-109, etc.
It is apparent from the foregoing description that the guide rollers 108-109, the input rollers 24-25, and the output rollers 27-28, must all have arcuate lands and grooves which intermesh to form a nip which matches the corrugations of a strip S. The curling die rollers 29-35 also have such lands and grooves. This is illustrated in Figs. 8-10, which show the output rollers 27-28 in conjunction with the strip S, and a locking mechanism which will be described in detail hereinafter. Accordingly, it will be understood that all the rollers which feed or guide the strip have identical lands L and grooves G as indicated in Fig. 9.
Referring further to Figs. 8-10, there is illustrated a mechanism 110 for locking together overlapping layers of the corrugated strip as it is being formed into a flexible tube. The lower output roller 27 has subportions 27B and 27C which are spaced to provide a gap 27D in which a bushing 111 is mounted on the lower output shaft 27A. The bushing carries a crimping wheel consisting of a collar l12 and several equally spaced bifurcated crimping spokes 113 having resilient arms 113A and 113B of spring steel which normally abut the adjacent ends of the subportions 27B and 27C.
The crimping wheel rotates generally with the lower output roller 27, though it may rotate relative to the roller. As a bifurcated spoke 113 enters the nip of the rollers 27 and 28, as shown in Fig. 10, a pair of lands Ll and L2 of the upper roller 28, which are spaced by double the width of a corrugation, contact respective camming surfaces 114 and 115 of the arms 113A and l13_B to force the arms toward one another so that respective opposed crimping jaws 116 and 117 of said arms firmly pinch the overlapping plies of the flexible tube to crimp and lock said plies together into the shape shown. The pinching action of the jaws l16 and 117 is released as continued rotation of the outfeed rollers 27 and 28 drive the spoke 113 out of the nip of the rollers.
In the space between the lands Ll and L2 is a circumferential rib 118 which provides an anvil to prevent buckling of the walls of the corrugated strip as the lock is formed.
The spacing of the resulting locks about the periphery of the tube is determined by the spacing of the arms 113 about the collar 112.
Alternatively, each of the spokes 113 of the crimping wheel may consist of a single spring arm which is moved against and crimps the plies of the corrugated strip from one side only. In such a case, successive spokes would consist of an arm corresponding to an arm 113A and an arm corresponding to an arm 113B, so that successive spokes would be moved against the plies of the strip from opposite directions.
The curling die is adjustable so that it may fabricate flexible tube from about 50.8 mm (2 inches) to about 508 mm (20 inches) in diameter. If a tube to be fabricated is to have a diameter in the extreme lower part of this range, then the rollers 29 and 35 must be removed as illustrated in Fig. 13.
The bending device 119 comprises a pivoted plate 119a which is mounted upon the gear housing 41 coaxial with the lower outfeed roller 27. A gear segment 120 on the plate 119a meshes with a worm 121 that is formed upon a manually rotatable spindle 122. A bending roller 123 is journaled upon a spindle on the plate l19a where it normally occupies an operative position between the nip of the infeed rollers 27-28 and the first curling die roller 29. A bending pin 124 may also be used with the bending roller 123.
When or not the bending device 119 is used during a curling operation depends both upon the diameter of the tube being formed and upon the stiffness of the material in the strip S.
The least expensive of suitable aluminum stock which is available in the U.S. market is of the stiffness used in the standard aluminum foil trays in which frozen foods are packaged. That material is stiff enough that the bending device 119 desirably is used regardless of the diameter of the tube that is being formed. The manually rotatable spindle 122 with its worm 121 is used to locate the roller 123 in the proper position between the rollers 27-28 and the first idler roller 29 or 30, as the case may be.
At the present time any aluminum strip which is softer than that used for freezer trays must be custom fabricated, and it is thus enormously more expensive. However, where strip material of about half the hardness of the freezer tray stock is used, the bending device 119 is required only for the fabrication of tubes smaller than about 76.2 mm (3 inches); and for larger tubes the bending attachment may be swung entirely out of the way by turning the spindle 122.
As seen in Fig. 13, when a tube of about 50.8 mm duameter (2 inches) is being formed, the axis of the bending roller 123 is almost precisely where the axis of the removed idler roller 129 is located.
The foregoing detailed description is given for clearness of understanding only and no unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.

Claims

1. Apparatus for helically curling longitudinally corrugated thin strip material into a flexible corrugated tube, said apparatus comprising, in combination:

(a) a curling unit comprising,

(1) a base,

(2) two forwardly extending rotatably driven input rollers carried on said base near one side thereof, said input rollers having intermeshing arcuate lands and grooves forming a nip which matches the corrugations of a strip of material to be helically curled,

(3) two forwardly extending rotatably driven output rollers supported on said base, said output rollers having intermeshing arcuate lands and grooves forming a nip to receive a strip of material from said input rollers.

(4) idler rollers supported on the base which have arcuate lands and grooves to guide said strip of material from the input rollers in a helical path in which each successive turn of the strip passes through the nip of the output rollers in partially overlapped relationship with the strip entering said output rollers, and

(5) locking means for intermittently crimping overlapping parts of said strip to lock said parts to one another; and

(b) a cassette having

(1) a frame with a plurality of sides,

(2) means on said frame to rotatably mount a reel of said thin strip material,

(3) a strip outfeed opening in one of said frame sides,

(4) two guide rollers in said outfeed opening, said guide rollers having intermeshing arcuate lands and grooves forming a nip which matches the corrugations in said strip of material, and

(5) means detachably mounting said cassette on the base with the nips of said guide rollers and of said input rollers immediately adjacent one another and substantially coplanar.

2. The combination of claim 1 in which one of the cassette frame sides comprises a pair of panels, and upright hinges one of which is on the cassette frame side having the strip outfeed, said panels being mounted on said hinges for movement between normal coplanar positions confining a reel in the cassette and substantially parallel positions permitting a new reel to be mounted in the cassette.

3. A cassette to receive a reel of longitudinally corrugated thin strip material which is to be helically curled in a curling apparatus to form a flexible corrugated tube, said curling apparatus having driven input rollers with intermeshing lands and grooves forming a nip to receive the strip, said cassette comprising, in combination:

a frame with a plurality of sides;

means on said frame to rotatably mount a reel of said longitudinally corrugated thin strip material;

a strip outfeed opening in one of said frame sides;

two guide rollers in said outfeed opening, said guide rollers having intermeshing arcuate lands and grooves which form a nip that matches the corrugations in said strip of material;

and means for mounting said cassette on a curling apparatus with the nips of said guide rollers and of the curling apparatus input rollers immediately adjacent one another and substantially coplanar.

4. The combination of claim 3 in which one of the cassette frame sides comprises a pair of panels, and upright hinges one of which is on the cassette frame side having the strip outfeed, said panels being mounted on said hinges for movement between normal coplanar positions confining a reel in the cassette and substantially parallel positions permitting a new reel to be mounted in the cassette.

.5. Apparatus for helically curling longitudinally corrugated thin strip material into a flexible corrugated tube, said apparatus comprising, in combination:

a base;

two output rollers fixed to respective first and second forwardly extending driven shafts which are supported on said base, said output rollers having intermeshing arcuate lands and grooves forming a nip which matches the corrugations of a strip of material to be helically curled so as to drive said strip;

idler rollers supported on the base which have arcuate lands and grooves to guide said strip of material from the input rollers in a helical path in which each successive turn of the strip passes through the nip of the output rollers in partially overlapped relationship with the strip entering said output rollers;

locking means for intermittently crimping overlapping parts of said strip to lock said parts to one another, said locking means comprising a plurality of crimping spokes carried on said first shaft in a circumferential gap in the lands and grooves of the roller on said first shaft, said gap being located where the successive turns of the strip are overlapped, and each of said spokes having facing crimping jaws at its outer end,

a shallow circumferential rib on the roller on said second shaft between two lands and in the plane of said jaws, said rib providing an anvil,

and means to close the crimping jaws on the sides of overlapped corrugations of the strip and press said overlapped corrugations against the anvil to form locks in said overlapped corrugations, and successive ones of said arms forming spaced locks as the rollers rotate.

6. The combination of claim 5 in which the spokes are free to rotate on the first shaft.

7. The combination of claim 5 or 6 in which there is a collar in the gap in the roller on the first shaft and each of the crimping spokes consists of a pair of spaced, resilient arms fixed to the collar with the crimping jaws at their outer ends, and the means to close the crimping jaws comprises laterally outwardly facing camming surfaces on the resilient arms adjacent said jaws, said camming surfaces bearing on the two lands of the roller on the second shaft which immediately flank the anvil so as to flex the arms inwardly as they pass through the nip of the rollers.

8. Apparatus for helically curling longitudinally corrugated thin strip material into a flexible corrugated tube, said apparatus comprising, in combination:

a base;

an upright support which is mounted on said base;

two output rollers fixed to respective first and second forwardly extending driven shafts which are mounted on said upright support, said output rollers having intermeshing arcuate lands and grooves forming a nip which matches the corrugations of a strip of material to be helically curled so as to drive said strip;

a spider carried on said upright support;

idler rollers mounted on said spider which have arcuate lands and grooves to guide said strip of material from the input rollers in a helical path in which each successive turn of the strip passes through the nip of the output rollers in partially overlapped relationship with the strip entering said output rollers, said idler rollers being journaled on spindles all of which are equidistant from the longitudinal axis of a tube formed by the curling of the strip;

spindle adjusting means for moving said spindles radially and retaining them in predetermined radially equidistant positions from said longitudinal axis;

spider adjusting means for moving the spider vertically on the upright support to change the distance between the output roller nip and said longitudinal axis, said spindle adjusting means and said spider adjusting means permitting the apparatus to form tubes of different diameters;

and locking means for intermittently crimping overlapping parts of said strip to lock said parts to one another.

9. The combination of claim 8 in which the spindle adjusting means and the spider adjusting means are operatively connected so that adjustment of all said spindles and said spider is carried out simultaneously.

10. The combination of claim 9 in which the spider adjusting means comprises a threaded support nut fixed to the upright support and an upright screw in said nut operatively connected to the spider to raise and lower the spider, the spindle adjusting means comprises a threaded spindle nut fixedly connected to each spindle and a radial screw in each spindle nut for moving the spindle nuts radially, and there is a gear drive for simultaneously rotating said upright screw and all said radial screws.

11. The combination of claim 10 in which the gear drive comprises a bevel gear journaled on the spider for rotation about an axis which is a rearward projection of the longitudinal axis of the tube being formed, a bevel pinion on an end of each of said screws, all said bevel pinions meshing with said bevel gear, and means for rotating the bevel gear.

12. The combination of each one of claim 8 to 11 in which the upright support is pivoted on the base on a vertical axis, and there is cooperating means on the base and on the spider for pivoting the upright support about said vertical axis through an arc which is proportional to the vertical movement of the spider and the radial movement of the spindles, so as to adjust the lead angle of the helical path to coincide with the diameter of the tube being formed.

13. The combination of claim 12 in which the cooperating means on the base and the spider comprises a depending fixed plate on the spider which has an upright arcuate cam slot behind the vertical axis of the upright support and a cam follower mounted on the base, said cam follower being traversed by the cam slot as the spider is moved vertically so as to pivot said upright support on said vertical axis.

14. The combination of claim 8 which includes a strip bending device on the upright base immediately adjacent the output rollers to contact the strip and curl it toward the first of the idler rollers, and means for adjusting the position of said bending device depending upon the diameter of a tube which is being formed.

15. The combination of claim 14 in which the bending device comprises a bending roller which has arcuate lands and grooves which match the corrugations of the strip of material, and a manually operable worm and gear sector for moving said bending roller into a desired position.

16. The combination of claim 15 in which the bending device also includes a removable bending pin which is selectively usable in cooperation with the bending roller to bend the strip before it reaches the bending roller.

17. Apparatus for helically curling longitudinally corrugated strip material into a flexible corrugated tube, said apparatus comprising, in combination:

(a) a curling unit comprising two input rollers, having intermeshing arcuate lands and grooves forming a nip which matches the corrugations of a strip of material to be helically curled, two output rollers having intermeshing arcuate lands and grooves forming a nip to receive a strip of material from said input rollers, guide means to guidesaid strip of material from the input rollers in a helical path in which each successive turn of the strip passes through the nip of the output rollers in partially overlapped relationship with the strip entering said output rollers, and locking means for intermittently crimping overlapping parts of said strip to lock said parts to one another; and

(b) a cassette having means to rotatably mount a reel of said strip material, a strip outfeed station, outfeed guide means at said station to guide the strip of material from the reel, and means for detachably mounting said cassette on the curling unit with the strip outfeed station and the nip of said input rollers immediately adjacent one another and substantially coplanar.