US3548724A - Apparatus and method for forming indefinite length tubular articles - Google Patents

Description

United States Patent 11113,548,724

72 Inventor Marcus A. Hall 561 References Cited Summer Island, Brani'ord, Conn. UNITED STATES PATENTS gi 1 2,828,239 3/1958 Fischer 156/195 {2 i i' 1970 2,893,296 7/1959 Yovanovich 93/80 9 [73] Assignee Automation Industries, 1 55,559 11/1964 Hall l56/429X a corporation of California Primary Examiner-H. A. Kilby, Jr.

Attorney-Roy L. Parsell ABSTRACT: A collapsible mandrel surface comprising an endless belt helically wound on a hollow cylindrical stationary mandrel core so that the belt is moved along the helical course [54] from a first end to a second end of the core by driving pinions 19 claim 21 Drawin Fi mounted within the hollow core which protrude through the g core wall to engage the belt. Wail material in the form of a [52] US. Cl 93/80, strip is fed tangentially on to the moving belt so that as the belt 156/195 travels from the first end to the second end the strip is wound [51] Int. B3lc 1/00 on a portion of itself and cemented. By the time the formed [50] Field of Search 93/80; tube reaches the second end it is sufficiently self-supporting to allow the mandrel surface to be collapsed.

'I ulmm: ILIIIIllllllllllllllllillllil lll'll PATENTEU ED221973 sum 1 BF a WM W H PATENTEUBEB22|970 3548724 SHEET 3 [IF 4 INVENTOR. jlnrrcas 19. 174 22 APPARATUS AND METHOD FOR FORMING INDEFINI'IE LENGTH TUBULAR ARTICLES This invention relates to the manufacture of indefinite length tubular articles of the type which are fabricated on a mandrel. More particularly, this invention relates to an improved mandrel apparatus and method which fabricates the continuous type of article. j

Due to the continuous process method, the 'mandrel must be flexible enough to be collapsed at the proper time for removal of the tubular article when that article is sufficiently formed to support itself and yet be rigidly supported during the fabrication of the tubular wall of the article while on' the mandrel.

This is accomplished by providing (1) a rigid mandrel core to support (2) a flexible mandrel surface and'(3) means for moving that mandrel surface from the condition of being rigidly supported to the condition of being collapsed.

It is therefore one of the objects of my-invention to provide an improved mandrel core. j

Yet another object is to provide mandrel surface moving means applied at a desired location on that surface.

And another object is to provide a mandrel surface moving means which may be disposed within the mandrel core.

While a further object is to provide improved guideways to receive the moving mandrel surface. 1

Another object is to provide an impro' ed collapsible mandrel surface. f

And yet another object is to provide improved means for moving the collapsible mandrel surface over the mandrel core.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a plan view of my apparatus;

FIG. 2 is a side elevation partly in perspective of a portion of the apparatus shown in FIG. I;

FIG. 3 is an end elevation of the apparatus shown in FIG. 1 as viewed from the left end as shown-on the drawing of FIG. 1;

FIG. 4 is a plan view, partially in section and somewhat enlarged, of a portion of the mandrel core as shown in FIG. 1;

FIG. 5 is a vertical section taken on line 5-5 of FIG. 4;

FIG. 6 is a vertical section somewhat enlarged taken on line 6-6 of FIG. 5;

FIG. 7 is a schematic view showing the angular displacement of a group of driving pinions;

FIG. 8 is a view of a portion somewhat enlarged of the finished tubular article as produced by the apparatus embodying the invention; v

FIG. 9 is a vertical section'somewhat enlarged taken on line 9-9ofFIG.l; f 1

FIG. 10 is a vertical section somewhat enlarged taken on line 10-10 of FIG. 9; v

FIG. 11 is a vertical section showing another embodiment of my invention relating especially to a form of moving mandrel surface belt;

FIG. 12 is analogous to FIG. 11 in showing another embodiment of the disposition of the belt; 1

FIG. 13 is a schematic view showing the wall fiexure when a tubular article is bent in a curve position;

FIG. 14 is a cross section showing still another embodiment involving the belt surface;

FIG. 15 is an enlarged longitudinal cross section of a portion of the tubular article wall formed on the belt embodiment shown in FIG. 14; 1

FIG. 16 is a longitudinal vertical cross-sectional view of the mandrel core which is the subject of another embodiment;

FIG. 17 is a cross-sectional view taken on line 17-17 of FIG.

FIG. 18 is a cross-sectional view taken on line 18-18 of FIG. 16;

FIG. 19 is a perspective view of a section 'of belt in another embodiment;

FIG. 20 is a perspective view of a section of belt in still another embodiment; and

FIG. 21 is a sectional view taken on line 21-21 of FIG. 2.

Referring now to the drawings Pics. 1 and 3) numeral 11 denotes a base plate or portion of a frame on which the essential components are mounted. The base plate 11 is supported by a suitable frame, not shown, which in turn supports other accessories including a driving motor.

A vertical supporting plate 12 (FIGS..2 and'S) is mounted on base plate 11 fur supporting hollow stationary cylindrical mandrel core 13 by fixing one end to the plate 12.

The mandrel surface is in the form of a moving endless belt 18 surrounding the mandrel core 13 in helical convolutions 19 so that as the wall material 20 in the form of a continuous strip is laid on belt 18 at one end of the core-13 (right as viewed in FIGS. 1 and 2). It is both wound on and the tube just formed is advanced to the opposite end of the core 13 (left as viewed in FIGS. 1 and 2). In order to make the tubular article self-supporting the strip of wall material is laid on a portion of the preceding layer as an overlap 49 and secured thereto by a suitable cement or adhesive material (not shown) which is fed into the nip between the two adjoining faces of the overlap portion 49.

In order that the tubular article 52 now formed may be continuous, the moving mandrel surface is collapsed at the outboard end 44 (FIG. 5) after the cement issuffrciently set so that the tubular article 52 is self-supporting, by directing the advancing belt 18 into the interior of the mandrel core 13 to be returned to the starting end of the 'core 13 as will be described in more detail later. I

For added strength and other reasons I mayinsert a continuous spiral springlike reinforcing wire 33in between the layers of wall material comprising the overlap 49 as will also be described in more detail later.

The collapsing of the mandrel surface 18 comprises th guiding of the belt 18 from the helical convolutions 19 on the outside of the mandrel core 13 into theinterior of the mandrel core 13 through which it moves overx'the first and second sheaves 24 and 25 respectively to the beginning area on the outside of the core 12.

The first sheave 24 is provided with tension adjusting means (FIG. 2) by mounting its axle 46 on a sliding bearing member 47. This member is moved horizontally by a fluid operated piston and cylinder 48 to effect the desired tension in the belt 18 upon operation of suitable valves (notshown).

In the preferred form of my invention,(FlGS. 4, 5 and 6) I provide the belt 18 with teeth 38 having a=uriiform pitch which engage teeth 39 on drive pinions 15, 16, and 17 respectively so that upon rotation of the pinions the convolutions 19 of the belt 18 are advanced along their respective helical courses.

Referring again to FIGS. 4, 5, and 6, the drive pinions l5, l6 and 17 when properly adjusted angularly are fixedly mounted on drive shaft 14. This drive shaft 14 is journaled in the mandrel core 13 by suitable means (not shown) and extends through plate 13 to receive a sprocket 21 and chain 21a driven by an electric motor 26.

An aperture 53, formed in the wall of the core 13, enables the pinions 15, 16, and 17, when mounted in the interior of the core, to extend through the wall of the core 13 to engage the belt 18.

In the preferred embodiment I provide properly formed teeth 39 on the pinions 15, 16, and 17, and teeth 38 on belt 18 so that a uniform rate of surface speed is imparted to the several convolutions 19 of belt 18 which may be recognized in FIG. 6 as analogous to a pinion (15 for example) driving an annular gear (the belt convolution 19). By the term properly formed teeth I refer to a type of gear teeth having a uniform pitch. I

I may also form the teeth 38 and 39 on' a skew angle (FIG. 4) so that the direction of the force F as applied corresponds to the angle II of the helical convolutions 19 and thus tending to maintain the belt in the center of the helical groove 22.

It will now be apparent that one of the important features of my preferred embodiment is the application of the force to move the belt 18 and so applied in and adjacent to the area where the wall material 20 is tangentially applied under tension of the strip of wall material. This tension results in a general radial pressure against the outside surface of the belt 18 and is transmitted through the belt and distributed to the convex surface of the core 13.

In order that the pull on the belt' 18 by the drive pinions 15, 16, and 17 and the radial pressure just mentioned will not cause the belt to grab or bind on the surface of the core 13 it is desirable to have a slight radial clearance y (FIG. 6) between the outside surface of the core 13 and the inside surface of convolutions 19 of belt 18. This is obtained by positively feeding the belt from the first pinion to be taken up by a second pinion 16 at the same belt lineal rate of speed so that a desired amount of slack belt exists in the convolutions between the first and second pinions and subsequent pinions.

Since the teeth 3? positively engage the belt 18, the length of the belt in one full convolution between adjoining pinions 15,16, 17, etc. respectively is unvarying. Each pinion is keyed in place on the sha t 14 inre ation to the adjoining pinions so that the length of the belt 18 maintained in one full convolution is greater than the length in one convolution along the bottom of the helical groove 22. In this fashion it is made cer- 'tain that the belt 18 will always be spaced from the bottom of clearance y and that this clearance can be represented by the thickness of a pilot or special length of clearance belt 13 of thickness y which can be laid on the surface of the core corresponding to the convolution between the pinions but stopping short before the pinions so as not to be engaged thereby. Then the belt 18 is placed in position over this special belt 18' and engaging the teeth of the respective pinions in a belt engaging sector. To properly mesh the teeth of the respective pinion with the belt (which is held against the clearance belt 18') the pinions may require angular positioning on shaft 14 to be described later. When properly positioned, the pinions are fixed to the drive shaft 14 by any suitable means such as set screws. As the shaft 14 is driven by the source of power the pinions pay out the slack and move the belt 18 with the proper clearance and lineal rate of belt speed.

The angular positioning of the belt engaging sections of the pinions to correlate the clearance slack in the belt convolutions between the teeth engaging sectors of the respective pinions is thus illustrated schematically in FIG. 7.

Assume tooth T to be at the center of the belt engaging sector (see are K FIG. 6) of first pinion 15; T the corresponding center tooth for belt engaging sector K for pinion 16 and T the center tooth for belt engaging sector K" for pinion 17.

Then with pinion 15 fixed to drive shaft 14, belt 18 is placed in its proper position meshed with pinion 15, pinion 16 is rotated on shaft 14 if necessary for proper meshing with belt 18 and then fixed to shaft 14 by a set screw. The relative position of tooth T to a vertical reference line OM is indicated by angle d and the position of tooth T' by angle d.

A similar procedure is followed for pinion 17 and as shown in FIG. 7 tooth T" coincides with the vertical reference line OM".

It may also be observed that the pinions may not be drive pinions but as pinions fixed to a common rotating shaft merely to regulate the clearance slack in the belt convolutions since the belt may be driven by other means than the aforesaid pinions as for example by. the outside circumferential surface of belt being driven by outside means While in certain of the drawings (FIGS. 4, 5, and 6) the aperture 53 in the mandrel core 13 through which the pinions engage the belt 18 appears at the top of the mandrel core this aperture 53 is not limited to the top and may be in any suitable position about the circumference of the mandrel core.

Also the drive pinions as described are mounted on a single drive shaft but depending on the size of the mandrel the drive pinions may be mounted on separate drive shafts. Furthermore, under certain conditions the guideways 22 may be omitted.

The reinforcing medium previously referred to is preferably a wire 33 having a predetermined resilience so as to be formed into a sort of helical spring. It first passes through a series of feed rolls 58, then passes through a second set of tube diameter forming rolls 59 to form the wire 33 to the desired diameter of the finished article 52. Next the wire, now in helical spring form, is engaged by a pitch forming roll 60 (FIG. 10) which crimps the wire 33 with an elongating bias which is restrained by the wall material of the tubular article 52, conversely biased as a retracting pitch tending to contract the tubular article 52 longitudinally or to be biased neutrally as regards contracted or extended pitches.

And finally (FIG. 1) the wire 33 is laid on the trailing portion of the convolution of the wall material already on the belt where it will be subsequently covered by the overlap portion 49 of the next succeeding layer of wall material 20.

The operation of laying on the wire 33 is controlled by a wire locating arm 54 mounted on an axis parallel to the axis of the mandrel core 13 so that one end carrying a grooved finger 55 which presses against the moving beltby suitable adjustable pressure means. The groove 55' receives the wire and guides and tensions it to the desired position on the wall material which is subsequently covered by the overlap 49.

In another embodiment of my invention as shown in FIGS. 16, 17, and 18, I provide that the bottom of the first guideway convolution 22a shown at the right, as viewed in FIG. 16, to be slightly deeper x than the next succeeding guideway convolution 22b so that the outside surface of belt 18 reposing in the first guideway convolution 22a is substantially flush with the convex surface of the mandrel core 13.

The deepest point of this first guideway conv0lution22a is located at the tangent point (seex FIG. 16) where the wall material strip 20 is laid to the belt 18 and gradually enlarges to the normal diameter of the next guideway convolution 221) within the first full turn of the strip 20.

The purpose of making the belt surface in-the first guideway flush with the surface of the mandrel core is now explained. When the continuous strip of wall material 20 is fed on to the moving mandrel surface it is under a tension and as it is deposited on a previous layer on which the reinforcing wire is already placed to form the overlap 49 and also cover up the convolution of wirethere would be a tendency to wrinkle the wall material 20 already placed on the belt 18 ifthat first already placed wall material 20 was placed on a belt 18 surface of normal diameter (which it is not) of the belt convolution. Therefore by placing the first layer of wall material 20 on a convolution portion of the belt having a slightly smaller diameter than the subsequent normal belt convolutions when that first and original belt convolution layer reaches the position of the second or larger diameter convolution the slack causing a wrinkle is thus absorbed in theportion which forms the original layer which prevents the forming of wrinkles.

In this connection it will be noted from FIGS. 17 and 18 that the pinions are disposed in a 10 oclock position (as viewed in.

It will now be obvious the diameter of the circumference of the bottom of the first guideway is smaller than that of the second or normal guideway. However this difference in the.

respective corresponding circumferences will not interfere with the uniform lineal travel of the belt 18 on the mandrel surface after receiving the wall material since the first pinion draws from the slack of the preceding portion of the belt which will lie in the bottom of the first guideway and will feed. the belt to the second pinionat the predeterminedrate for the clearance previously mentioned.

In another embodiment of my invention (FIG. 12) I may space the convolutions of belt 18 so that aconvex surface of mandrel core 13 lies exposed between successive convolutions and at the same time is below the surface of belt 18. The width of belt 18 (measured-in a generally normal direction to the course direction of the belt) is greater than the extent of the overlap of the layer of wall material between which the reinforcing wire is laid.

The wall material 20, thus laid partly on the mandrel core and partly on the, belt 18, develops a sageffect S (FIGS. 11 and 12). In other words the diameter of the finished tubular article is slightly greater at the center'of the belt section than at the midpoint between convolutions 19.' This results in a finished tubular article. which is easily bent due to the low point of the sag moving radially inward as shown in FIG. 13.

Another advantage of the spaced and, raised belt convolutions is to reduce the friction of the fabricated tubular article along the convex surface of the mandrel core as it is advanced.

In another embodiment (FIG. 11) 1 form the outside surface of belt 18 with a convex cross section' and with the belt convolutions closer together than in FIG. 12 which also results in a sag effect S to improve the flexibility of the finished tubular article due to the radial inward movement at midpoint previously described.

In still another embodiment (FIG. 14) I' provide a belt 18 with a groove 56to receive the reinforcing. wire 33 so that the overlap is formed with a portion of the 'wirecross section partially embedded. in each of the respective layers of wall material comprising the overlapped portion 49 as further shown in FIG. 15. 1

Another embodiment (FIG. 19) using a belt 18" having the teeth located in the center portion of the belt cross section provides a wall 57 to bear. on the convex surface of the mandrel core so that the radial force bearing on this convex surface is distributed over a substantial area rather than on the ends of the teeth. In still another embodiment the belt 18 may take the form 18" as shown in FIG. 20. i

An adaptation of the foregoing idea'is' shown in FIG. 20 where the radial force is distributed at the'center of the belt cross section with the teeth on either side-of this center portion to relieve the wear on the tips of the teeth.

Although I have described my invention with a certain degree of particularity, it is understood that thepresent disclosure has been made only by way of example and that numerous changes .in thedetails of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

Iclaim: I "j 1. In an apparatusfor making indefinite length tubular articles from a continuousstrip of tangentially. fed material on a collapsible moving mandrel surface device comprising an elongated stationary mandrel core having a longitudinal passageway extending through the interior of said core from a first end to the opposite second end; an endless moving belt so disposed as to longitudinally surround said core and to move in a course having a=pluralityof spacedhelical convolutions engaging the outside surface of said core and extending from said first end to said second end forming-a moving mandrel surface portion during the advance of said belt from said first end. to said second end and forming a return portion during the returning movement of said belt fromsaid second end through said passage to said first end; and means for moving said belt along said course.

2. In the device of claim 1 said moving means comprising a driven wheel disposed in said core in driving engagement with saidbelt. '1;

3. In the device of claim 2 said wheel and said belt respectively provided with meshing pitch gear teeth..

4. In the device of claim 1 means for driving said belt com.-

prising said core "having an aperture connecting said. passageway with said outside surface; a drive. shaft mounted in 5. In the device of claim 1 means for'driving said belt comprising a drive shaft mounted in said passageway; a plurality of drive pinions having belt engaging sector portions; said pinions fixedly mounted on said shaft; and said belt having gear teeth for engagement with said pinions. v

6. In the device of claim 5 said pinions so disposed relative to the line of tangential engagement'of the material strip with said mandrel surface portion that said'sectorportions are adjacent said line of tangential engagement.

' 7. In the device of claim 6 'd pinions so disposed that the relative angular position of the respective belt engaging sectors on said pinions is such that the length of moving belt between adjacent pinions is maintained at a constant length for a desired radial clearanceof said belt with the surface of saidcore.

8. In the device of claim 1 said core havingguideway convolutions formed in the outside surface? thereof for receiving said belt convolutions. o

9. In the device of claim 8 a first guideway convolution adjacent said first end having a first belt convolution therein; a second guideway convolution adjacent said first guideway convolution toward said second end having a second belt convolution therein; said first guideway convolution having a portion recessed deeper than said second guideway convolution so that a substantial portion of said first belt convolution maintains a less radius than said second belt convolution whereby the trailing edge portion of the material strip reposing thereon will resist wrinkling as it advances tothe second belt convolution.

10. In the device of claim I a plurality of pinions fixedly mounted on a single shaft disposed insaid passageway; said pinions engaging said belt convolutions whereby the length of belt between respective adjacent belt engaging sectors of said pinions is maintained at a constant length.

11. In the device of claim 5 recessed continuous helical guideway convolutions disposed in spaced relation on said core to receive said belt convolutions; said belt convolutions disposed in said guideway convolutions; said guideway convolutions having a depth such that said mandrel surface portion is above the adjacent outside surface of said core so that the wall of the tubular article formed on' said surface portion will have a space in which to sag against said outside surface between adjacent convolutions. f

12. In the device of claim 11 said belt having a laterally convex outer surface. 7

13. In the device of claim 1 said belt having a continuous groove recess in its outer surface for receiving a portion of the said passageway; a drive pinion fixedly mounted on said shaft and extending through. said aperture in driving engagement with said belt whereby said belt is moved onsaid course.

reinforcing element.

14. A mandrel device for making indefinite'length articles comprising: 1

a. a hollow generally cylindrical tubular core supported at one end and free at the opposite end.

b. at least one flexible belt helically wrapped with spaced turns in a corresponding helical guideway convolution formed on the outside of said tubular core.

0. guide means on the free end portion of the tubular member for directing the belt from the helical guideway convolution around the free end'of the tubular core and into the interior thereof,

. sheave means for directing the belt'from the interior of the tubular core back to the helical guideway convolution adjacent the supportedend portion of the tubular core,

e. pinion means within said tubular core extending through aperture means therein into said helical guideway convolution in positive engagement with said belt for maintaining said belt in a slidable fit within said guideway convolution; and o f. drive means for positively displacing said continuous belt along said helical guideway convolution in engagement with said pinion means and thence around said guide means through the interior of said core to said sheave means and finally back to said helical guideway convolution.

15. A continuous method of making indefinite length artithereof by means of said moving belt, so that the fabricatcles from at least one extended fabricating element which ing element is advanced by said belt continuously from comprises: the free end portion of the mandrel surface in the form of a. forming a substantially cylindrical mandrel surface supsaid article.

ported at one end portion and free at the opposite end 16, A method according to claim 15 wherein said belt is positively driven in its helical path. I b. translating at least one spaced-tum helical belt defining 17. A method according to claim 15 wherein the indefinite -f f id surface i a corresponding h li l h length article made thereby is helically fabricated flexible tubtoward the free end portion of the mandrel surface, gv c. maintaining the remainder of said mandrel surface sta- A method accordmg to clam! wherein a P of tionary between the turns f id moving be", the replaced first convolution of the belt at the supported end d continuously conapsing the moving belt at the f end of the mandrel is maintained at a diameter less than the diameponion of the mandrel Surface ter of the succeeding belt convolution.

e. continuously replacing the moving belt at the supported In the f of claim 3 Said belt having a continuous end portion ofthe mandrel Surface and 15 portion extending throughout the length of the belt for enf. helically drawing the extended fabricating element about gagemem with the outside Surface of Said Corethe mandrel surface adjacent the supported end portion portion,

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