US2783532A - Tube bending method - Google Patents

Description

March 5, 1957 R. A. sANDBl-:RG

TUBE BENDING METHOD 5 Sheets-Sheet 1 Filed July 11, 1950 md E L l@ E A V ad TNS/a w v g v Hum/ NNN M March 5, 1957 R. A. SANDBERG 2,783,532

TUBE BENDING METHOD Filed July 11, 195o 5 Sheets-Sheet 2 IWFEZLDT Pay A- Sandberg M arch 5, 1957 R. A. sANDBERG TUBE BENDING METHOD Filed July-11, 1950 5 Sheets-Sheet 3 `lf;7z/E77UIT7 l 72615/ A. Sandberg Mmm 5, 1957 R. A. SANDBERG 2,783,532

TUBE BENDING METHOD Filed July 11, 1950 5 Sheets-Sheet 4 Pay A.. Sandbeg March 5, 1957 R. A. SANDBERG TUBE BENDING METHOD Filed July l1, 1950 5 Sheets-Sheet 5 Ray A. Sandberg MMM ffy/@5 United States Patent() TUBE BENDING lVIETHOD Ray A. Sandberg, Waukegan, Ill., assigner to Houdaille Industries, Inc., a corporation of Michigan Application July 11, 1950, Serial No. 173,083

2 Claims. (Cl. 29-550) The present invention relates to a tube bending machine and method. More particularly, this invention deals with a machine and method for winding elongated tubing stock into an irregular helical form which is subsequently opened up from its helical form to a sinuous tube length adapted for employment in heat exchangers or the like.-

In the prior art the formation of sinuous tube lengths for condensers or the like has been accomplished' by n bending a straight length of tubing about spaced and aligned gages and mandrels, the work being carried by a horizontal table surface, and oscillated or rotated about va plurality of centers with each bend changing its direction from its former bend by alternating from right to left to produce a serpentine sinuous path in a single plane. Such machines are large, complex, and expensive in manufacture and use and are limited to the number of coils and the length of coil between bends. This is true in all commercial production machines since it is necessary to sweep the entire preformed portion of the coil around the mandrel from right to left each time another 180 bend is made.

The present invention now provides a simple form of winding apparatus which is employed to spirally wind anY elongated length of tubing about forming means defining.

jecting therebeyond in planes parallel to the axis of ro` tation of the plate. Means are provided for training an elongated iiexible length of tubing about the mandrels as the plate is rotated about its axis, the tube training or feedingV means preferably being screw fed or otherwise advanced along the axis of rotation of the plate to spirally feed the tubing to the winding mechanism to thus form the helical tubing coil. The feeding means successively contacts the winding mandrels as the winding plate is rotated, thereby bending or otherwise deforming the tube about each mandrel in succession. In this manner, the

feeding means advances the tubing along the mandrels in a spiral conguration while at the same time forming smoothly curved tubing bends about each mandrel in turn. i

Mandrels are also provided for expanding the Winder frame or the mandrels when the winding operation has been completed to insure the formation of a smooth, geometrical helical coil, and means are also provided for contracting the Winder frame after the coil has been formed and expanded to facilitate removal of the same from the winding apparatus.

The method of v,the present invention thus contemplates the formation of a tubing coil having an irregular helical configuration, the expansion of the coil after formation toinsure the proper helical formation thereof, andthe.

F a l ce 2,783,532

contracting of the coil forming means to facilitate removal of the coil. Of course, the method of the present invention also includes the steps of feeding an elongated tubing length to a Winding frame, advancing the tubing lengths across the face of the frame to obtain a spirally wound coil and the maintenance of the winding pressure p on the tubing length as it is wound to obtain a uniform coil.

It is, therefore, an important object of the presentv invention to provide an improved machine for the tonnation of a helically wound tubing coil adapted for expansion into a sinuous tubing length.

Another important object of the present invention is to provide an improved method of forming a sinuous tube length by the winding of the tube into an irregular helix followed by expansion of the helix to a sinuous configuration.

An additional important object of the present invention i is to provide means for producing a sinuous tube whoseY overalllength between ends and the total' number of bends are not limited.

It is a further important object of the present invention to provide an improved tube bending machine including a winding frame rotatable about an axis, means for feeding a length of tubing to the frame for forming an ir' regular helical tubing coil thereabout, and means for expanding the tubing coil after winding is completed toj insure the formation of a smooth, regular coil.

Still another important object of the present invention is to provide a tube bending machine including a rotatable Winder plate carrying a plurality of spaced mandrels.

means for feeding a tubing length about the mandrels as the plate is rotated, and means for advancing the tubing along the axis of rotation of the plate to form a helical coil of the tubing about the mandrels.

Yet a further important object of the present inven-l tion is to provide a method of making a sinuous tubing length by feeding an elongated length of tubing about a plurality of spaced mandrels, advancing the tubing along the axial length of the mandrels to form a helical coilV thereon and subsequently opening up the helical coil into a sinuous tubing length.

Other and further important objects of the presentV invention will be apparent from the disclosures in the specification and the accompanying drawings.

On the drawings:

Figure 1 is a broken plan view of 1an apparatus ofi the present invention;

Figure 2 is a front elevational view of the apparatus of Figure 1;

Figure 3 is an enlarged fragmentary sectional viewY taken alongrthe plane III--III of Figure 1;

Figure 4 is yan enlarged fragmentary plan view similar l to Figure 1 and illustrating the apparatus having a coil of tubing wound thereon;

Figure 5 is an enlarged fragmentary front elevational v view showing an initial loop of tubing disposed thereon; Figure 6 is a front elevational view similar to Figure 5 illustrating one position of the apparatus during the winding operation;

Figure 7 is a greatly enlarged sectional view taken along 'the plane VII- VII of Figure 5;

Figure 8 is a front elevational view illustrating the apparatus having a formed tubing coil thereon;

Figure 9 is a view similar to Figure 8 illustrating thek expansion of the forming mandrels after winding has beenI completed;

Figure 10 is a view similar to Figures 8 and 9 show-r ing contraction of the winding mandrel after the` coil has been formed and immediately prior to removal of .the vcoil therefrom; l, .1 f

,Patented Mar. 5, 1951 Figure 11 is an elevational view of a helically wound coil of the present invention;

Figure 12 is ra plan elevational view of a finished sinuous condenser tube made in accordance with the present invention; and r Figure 13 is an end view of the sinuouslength of tubing of Figure 12.

As shown on the drawings:

In Figure 1 reference numeral 10 refers generally to an apparatus of the present invention including an upstandng support member 11 surmounted by a journal. 12 rotatably supporting therein a shaft 13 extending axially therethrough. y

The rear end of the shaft 13 has pinned thereto for rotation therewith a sprocket 14 receiving a driving sprocket chain 15 lapped about a driving sprocket 16 secured to the output shaft of a speed. reducer 18 driven byv a prime mover 17, such as van. electric motor or the` like. Y

The shaft 13 has secured thereto for rotation therewith a Winder plate 20. As best seen in Figure 2.,- the Winder plate 20 is generally rectangular in outline and has its geometrical center apertured to receive the shaft 13.

The shaft 13 carries thereon, immediately adjacent the Winder plate, a cam 21 which, as best illustrated in Figure 3, is provided with a rearwardly projecting boss 22 rotatably disposed on shaft 13. The cam is provided with an arcuate upper surface 24 provided with spacedtransverse grooves 25-27, inclusive. The boss 22 carries an upwardly extending arm 2S provided with a terminal flange 29 overlying the cam surface 24. The arm 28 carries directly beneath the ange 29 a vertically apertured guide block 30vslidably'receiving a locking pin 31 having a lower end resiliently urged, as by compression spring 32, into a selected one of the slots 25-27,A inelusive. A cam actuating arm 33 is secured to that edgev of the cam opposite the edge 24 to providev means. for rotating the cam about the shaft 13 upon lifting the locking pin 31 from the locking slots or recesses' 25-27. of the cam.

The cam 21 carries oppositely directed link arms 34-35 pivoted to the cam, as by pivot pins 36. The arm 35 carries at the free .end thereof a lshaft bolt 37 passing through an arm aperture 38 and throughV an. elongated' slot, 39,y in the plate Z0 (Figure 4'). The shaft bolt 37 has` its, head recessed ina cylindrical, winding mandrel 40 projectingA beyond the front face of the plate 20'. A nut 41 is threadedly retained on that end' of the shaft bolt 37 projecting beyond the arm 35 to secure the-arm 35, the shaft bolt 37, and the mandrel 40 into a movable unit.

The other arm 34 has its free end apertured as' atf 42 (Figure 7) to receive a 'shaft'bolt 43. Thel shaft bolt 43 pivotally-secures the arm 34 to a pair of links44 and 45, each havingfregistering apertures 46 therein receiving thebolt. The apertured. end of the upper link 44 is recessed, as -at 47, to accommodate the freerend of the arm 34, while the'lower link 45 is similarlyA recessed adjacentits apertured end, as at 48, to receive both the apertured ends of the link44. and the ann 34. The links 44 and 45 have secured thereto additional windingmandrels 49 and 59, respectively, each mandrel projecting fromgthe same surface ofthe plate 2t) as the mandrel40 hereinbefore described. Each of the mandrels 49. andY 50 is' secured to its link 44 and 45, respectively, byv a partially recessed vscrew 51 threadedly retained by the links and extending through corresponding elongated slots 53iand 54, respectively, in the plate 2).

It-l will be seen that upon manipulation of the handle 33 in a counter-clockwise direction, as seen in Figure 3,

following removal of thelockingV pin' 31 from' the' slot Y thereby spreading the winding mandrels 40, 49Yand5jtl arcanes 4 from one another and from the center of the plate. Convesely, upon actuation ofV the handle 33 in aY counterclockwise direction, the winding mandrels will be withdrawn toward one another. The position of the slot 25 in relation to the locking pin 31 indicates the furthest spreading movement of the mandi-els, while the rel-ation between the slot 27 to the locking pin 31 indicates the fully retracted position. Normally-that is, during actual winding operationsthe pin 31 is seated in the intermediate or operating. position slot 26.

Again referring to Figure 1 of the drawings, the shaft Y 13 carries, intermediate the cam 21 and the journal bearingA 12, aV sprocket 55- keyed thereto and receiving thereabout a sprocket chain 56 which is also lapped about a sprocket 57 keyed to a shaft 58 journaled within a bearing 59 carried by an opstanding support member 60 generally parallel to the support member 11 hereinbeforev described for the shaft 13. rThus, the shafts` 13 and 58 are geared together for rotation with the gearing ratio 'being determined, asis conventional, bythe comparative sizes and numbersof teeth of the sprockets' 55 and. 57. In the illustrated form of the present invention, the shafts are driven in a one-to-one ratio.

That portion of the shaft 58 projecting beyond the bearing 59 is threaded, as at 61, the threads having a lead which is correlated with the remainder of the apparatus as will be hereinafter more fully described. Theshaft 58 supports thereon a pressure bar 62 extending radially from the shaft toward the Winder plate 20 and carrying on its undersurface a feeding guide 63 having a lower downwardly opening elongated slot 64 best illustrated in Figure 7. That end of the pressure bar 62 overlying the shaft 58 is provided with a lower` feeding block 65 having an open bottomed arcuate topped slot 6.7 therein provided with an interior thread 68 in threaded engagement with the threaded portion 61 of the shaft 58.

It will be seen that, upon rotation of. the shaft 58,A the bar 62 and the feeding guide 63 will be advancedalong the length of the shaft 58 whichV is parallel to shaft 13` upon which the plate 20 is disposed. The feeding guide163. abuts one-or more of the winding mandrels 37,4 49 and 50 at all rotating positions of the plate 20. It is. desirable to taper that end 69 of the. feeding guide remote from the shaft 58 in order to insure smooth feed ing, ofV the tubingv about the extreme mandrel 40, as will be hereinafter described, and also to insure smooth con tact of this end of the feeding guide with the winding mandrels.

Itwill. be noted, particularly irr Figures 2 and 7 of. the drawings that; thel face of the plate 20 from which thewinding mandrels 40, 49 and 50 project is' provided with. an; elongated. tapering groove 70 extending inY a straightdine from the nndersurface ofthe windinglman drel.49.fto the undersurface of the windingl mandrel. 40, the: depth: of: the; groove' decreasing progressively from. thev mandrel; 49 to the: mandrel 40 and vanishingat the mandrel. 40 fora purpose to` be hereinafter more fully described. A clampingplatev 71 is secured by a suitablev means, as by-ar boltor screwV 72, to the same surface-ofv theplatezz to overlie a` portion of the groove 70.

TheY operation of the apparatus: hereinbefore describedv willlbe': appreciated in=Figures 4-10 of the drawings. To

-. initiallystart theV tube winding operation, a substantiallywithithefreeend. 81 ofthe tube length being positioned with; the; groove 70-and the extreme free end of the tubeunderlying. the mandrel'. 49'and projecting beyond the corresponding end surface of the-Winder plate 20.

That'portion 81 ofthe tube' 80 which is positioned within the grooveI 70 (Figure 7) islaterally displaced outside a vertical projection of theA extreme ends of the pressure'.barw62 and ofi the feeding. guide 63, while" that portinSS-of the tubing lengthr lapped about themandrelr40 directly*l underlies the feeding groove 64 of. the feedingrguide63 The reach of the tubestlextendingll'ie"-` tween the mandrels 40 and 49 andoverlying thesame is positioned within the groove 64the pressure bar maintaining the feeding guide 63 in contact with .the mandrels. Upon rotation of the plate 20 in a counter-clockwise direction, as indicated by the directional arrows of Figures and 6, it will be seen ,that the pressure bar 62 and the feeding guide 63 ride about the peripheryof the mandrel 49 until the position of Figure 6 is attained in which the feeding guide 63 contacts both the mandrels 49 and 50. Thus, the pressure bar smoothly deforms the tubing into surface contact with the mandrel 49, forming a smooth joining curve about a portion of the periphery thereof. j

Upon further counter-clockwise rotation of the plate 20 about the shaft 13, the pressure bar 62 will be lowered with the feeding guide 63 maintaining contact with the mandrel 50 until the feeding guide contacts the mandrel 50 and the mandrel 40. Upon further rotation, the feed guide will contact the mandrel 40 until the position shown in Figure 5 is again realized, thus completing a single revolution of the plate 20.

It will be understood that the feeding guide 63 of the pressure bar 62 is advanced axially along the threaded portion 61 of the shaft 58 as this shaft is rotated in conjunction with the shaft 13 of the plate 20 by virtue of the hereinbefore described sprocket and chain feed arrangement. The axial advancement of the bar 62 of the feeding guide 63 upon one rotation of the shaft 58 is preferably equal to approximately the outside diameter of the tubing 80, so that a spirally wound relatively tight tubing coil is formed upon continued rotation, as illustrated in Figure 4. lt will be appreciated that the slot 70, by

laterally displacing the terminal portion 82 of the tubing 80 from its position underlying the pressure bar and feeding guide, will prevent interference of this portion of the tubing during the initial winding operation and before axial advancement of the bar and guide has been realized.

Counter-clockwise rotation of the plate 20 is continued until a desired length of tubing has been wound about the mandrel, or until a coil of the desired number of superimposed turns has been built up. In the manufacture of a ten-pass refrigerator condenser, for example, winding is continued while the plate 20 passes through four complete revolutions, at the conclusion of which the plate 20 is in the position illustrated in Figure 8 and the tubing 80 is severed, as at 84 in Figure 8. Alternately, the tubing may be cut to a predetermined length before winding is initiated, so that severance after winding is unnecessary. Of course, in order to sever the tubing, the bar 62 and the feeding guide 63 are removed from contact with the tubing 80, and while so removed, the terminal tubing portion 84 is deformed downwardly relative to the plate 20 to the position indicated in dotted outline in Figure 8. In this dotted position, the tubing terminal portion 84 extends from the mandrel 4l) to overlie the mandrel 50, the tubing portion 84 thus overlapping or crossing the rst free end 82 of the tubing 80 and each of the superimposed helices of the coils.

Inasmuch as the complete coil 86 of tubing has been formed, it is now desirable to expand this coil to insure a tight symmetrical formation of the coil about the mandrels. This stretching is accomplished by removal of the locking pin 31 from its position within the central slot 26, within which it has been positioned during the coil forming operation, and the actuation of the lever 33 as hereinbefore described to bring the slot 25 into registry with the lower end of the locking pin 31. As hereinbefore described, this actuation of the lever moves the mandrels within their corresponding slots, thus stretching the coil from the center thereof to insure the formation of straight runs between the mandrels.

Next, to remove the coil 86 from its position about the mandrels, the mandrels are contracted by actuating the handle 33, after removal of the pin 31 from the position within the slot 25, so as to bring the slot 27 into registryl with the locking pin. While the cam 21 is in this position,` the pressure b'ar and Vguide are again 4ele-V vated and the coil is simply removed from the retracted mandrel. Y A

The coil which is thusformed comprises an irregular, preferably triangular, helix defined by straight tubing runs between curved tubing joining portions, the continuou's coile'd'tubinglength being spirally wound by virtue of'the advancement of the feeding guide during rotation. As more particularly illustrated in Figure l1 ofthe drawings, the finished coil 86 comprises elongated straight side runs 191 and' 92'j'oi'ned at one end by curved portion 93 and at the' other end by ashort base run 94. The free ends 82 andV 84 are joined to the terminal bend of the'coil bythe curved portions 93 thereof. The'v triangular helical coil thus formed is compact and small in overall size to facilitate handling and/or shipping during or prior to subsequent formation of the sinuous tubing length.

Upon opening or spreading the coil, the configuration of Figure l2 is obtained in which the runs 91 and 92 are parallel, with the short runs 94 being aligned to form joining portions between the runs 91 and 92 of the same turn, and the curved portion 93 joining the runs 91 and 92 of adjacent overlapping turns of the helical coil as originally formed.

As shown in Figure 12, the end 82 overlaps the short straight run 94 of the initially formed turn, while the terminal end 84 underlies the short reach 94 of the last formed turn, the end portions 81 and 87 also being parallel to one another and to the runs 91 and 92 hereinbefore described.

It will be seen that the end product prepared by the use of the apparatus hereinbefore described is a sinuous length of tubing well adapted for attachment to a heat exchanger plate to form a plate-and-tube type heat exchanger, such as that described in my pending application for patent, Serial No. 81,970, tiled March 17, 1949. now Patent No. 2,660,412, issued November 24, 1953, and assigned to the assignee of the instant invention.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

l. The method of forming a sinuous length of tubing or the like which comprises Winding flexible tubing or the like into a helix with each turn of the helix generally triangular in shape and including a pair of elongated runs of tubing or the like defining two sides of equal length of a triangle and joined by a relatively short straight run defining the base of a triangle and a curved portion joining one elongated run of one turn lying on one side of the helix with an elongated run of the succeeding turn lying on the opposite lside of the helix and each turn overlying the next successive turn and being generally coextensive therewith, and opening successive turns of said helix with successive short `straight runs overlapping and abutting portions of adjacent short runs and with the elongated straight runs all lying substantially parallel and generally at right angles to said short runs.

2. The method of forming a sinuous length of tubing or the like which comprises winding flexible tubing or the like into a helix with each turn of the helix generally triangular in shape and including a pair of elongated runs of tubing or the like defining two sides of equal length of a triangle and joined by a relatively short straight run defining the base of a triangle and a curved portion joining one elongated run of one turn lying ou one side of the helix with an elongated run of the succeeding turnv lying on the opposite side of the helix and with 'the curved joining portion ot approximately one-third the extent of the relatively short straight run and with each turn overlying the next successive turn and being generally coextensive therewith, and opening successive turns of said helix with successive short runs overlapping and in closely spaced relation to .portions of adjacent short r-uixs 11d with the .elongated straight -runs all lying sub stantally parallel and substantially equally spaced.

Referencias Cied in Vthe file .of .this patent UNITED STATES PATENTS 177,225 Dorning May 9, 1876 296,269 Beafnan' Apr, 1, 1884 527,856 Hokam 091.23, 1894 644,841 Allen Mar. 6, 1900 -664,771 `McCallu m Dec. 25, 190.0 1,171,148 Simonsn Feb. 8, l1916 1,243,352 Snedeker Oct. 16, 1917 1,483,985 Price v Feb. 19, 192.4

` Ia'cobus' Y Apr. 25, `1933 'Makley Oct.6, 1936 Huy-ett' Nov. 24, 11936 Greene Mar. 2, 1937 Stephens Nov. 26, '1940 Schoen- Apr. 28, 1942 `Shan'is V Apr. 26, v1949 Sandberg Nov. 24, 11953 FOREIGN PATENTS

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