US2454290A - Apparatus for bending work such as tubing into serpentine coils - Google Patents

Description

APPARATUS FOR BENDING wonx suca Nov. 23, 1948. A w. PAYNE 2,454,290

A3 TUBINGINTO SERPENTINE COILS Filed Aug. 1, 1946 5 Sheets-Sheet 1 arnzene/s.

A. W. PAYNE APPARATUS FOR BENDING WORK SUCH AS TUBING INTO SERPENTINE COILS Nov. 23, 1948.

5 Sheets-Sheet 2 Filed Aug. 1, 1946 INV- TOR. flewe WE flrrve/vexs.

Nov. 23, 1948. A. w. PAYNE APPARATUS FOR BENDING WORK SUCH AS TUBING INTO SERPENTINE COILS 5 Sheets-Sheet 3 Filed Aug. 1, 1946 i Y w a? TY w M m WP m m T M A 1 H m X A w a 0 ll IIHI 1 W i -m E flnrilll|rhlxl|r .@1/% //w i n T Q w\ N u 1% mm m IMNIMI I Q mm Q o QQN NQ m d 7 4 Nov. 23, 1948. A. w. PAYNE 2,454,290

APPARATUS FOR BENDING WORK SUCH AS TUBING INTO SERPENTINE COILS Filed Aug. 1. 1.946 I 5 Sheets-Sheet 4 IN ENTOR. & aer/wezu. aw:

Nov, 23, 1948. A. w. PAYNE 2,454,290

APPARATUS FOR BENDING WORK SUCH AS TUBING INTO SERPENTINE COILS 5 Sheets-Sheet 5 Filed Aug. 1, 1946 INVENTOR. 191 M )dW/YE BY w.md@ w fiw Patented Nov. 23, 1 948 APPARATUS "FOR BENDING WORK SUCH AS TUBING INTO SERPENTINE COILS Arthur W. Payne, Detroit, Mich., assignor to Bundy Tubing Company, Detroit, Mich., a corporation of Michigan Application August 1, 1946, Serial No. 687,668

. 21 Claims.

This invention relates to the fashioning of long lengths of material into coils and particularly coils of serpentine form.

The invention is especially directed to the fashioning or bending of tube or pipe into coils of serpentine form such as may be used in various kinds of heat transfer devices. For example, such coils may be used in the refrigeration industry for condensers or evaporators. The invention is, of course, applicable to the bending of any length of material such as rods or wire or the like into coils of serpentine form, but insofar as it is now known, the invention has its greatest utility inthe art of bending tubing. Accordingly, for convenience, the invention will be disclosed and shown with reference to the bending of tubing.

It will be appreciated that in a coil of serpentine form, alternate bends are reversed, or in other words are in opposite directions. If one could imagine one's self progressing along the length of the tube, a bend would be encountered to the left; the next bend encountered would be to the right, and so on. The side of the tube which is on the outside of one bend is on the inside of the next succeeding bend. This situation has made the procedure of fashioning serpentine coils a rather slow one requiring an excess amount of labor, particularly where a coil is made which has quite a large number of bends therein. Since the tubing to be worked into serpentine form is relatively long, it follows that in making a bend it is not feasible to swing the long length of tubing about a forming instrumentality and, accordingly, the coil itself is swung or oscillated about the instrumentality as it is being produced. Since alternate bends must be made in opposite directions, it has heretofore been necessary to rotate the tube on its axis substantially 180 each time a bend is made following the first bends This requires the turning of the formed coil with the tube. In other words, the coil has to be swung through 180 to reverse its position each time a bend is made. This has required the hand labor of an operator positioned so as to be able to grasp the coil and reverse its position for each bend. .As a result the fashioning process is slow and the labor cost factor is high. The reversing of the coil for each bend becomes progressively more difficult as the coil is formed. This depends, of course, upon how large the coil is from the standpoint of the length of the runs and from the standpoint of the number of bends made; the larger the coil, the more difii'cult the procedure.

The present invention aims to provide an apparatus for bending tubing into serpentine coil form without requiring the reversal of position of the coil each time a bend is made. In carrying out the invention a particular bending head mechanism is provided of novel form in conjunction with means for advancing the tubing in step by step manner as required and means for operating the mechanism. The apparatus can be set up for an automatic operation.

The above object is the general overall objec tive, but other objects and advantages will be appreciated as the following detailed description is considered in conjunction with the accompanying drawings:

Fig. 1 is a view illustrating an exemplary serpentine coil of tube.

Fig. 2 is a plan view of an apparatus for carry- .ing out the invention.

Fig. 3 is an enlarged general view of the apparatus showing parts in section substantially on line 3-3 of Fig. 2. I I

Fig. 4 is a view of the driving mechanism looking substantially on line 4-4 of Fig. 3.

Fig. 5 is a sectional view showing the bending rolls and taken substantially on line 5-5 of Fig. 3.

Fig. 6 is a sectional view showing a part of the bending head and a clamp arrangement and taken substantially on line 6-6 of Fig. 3.

Fig. 6a is a sectional view taken substantially on line Biz-6a of Fig. 3 showing the clamp structure.

Fig. 7 is an enlarged plan view illustrating the driving mechanism for advancing the tube.

Fig. 8 is a view of the driving mechanism for advancing the tube partly in side elevation looking from the lower side of Fig. 7 and with some parts, shown in section.

Figs. 9 to 14 inclusive are views of a diagrammatic nature illustrating several progressive positions of the bending mechanism.

Fig. 9 shows an initial or at rest position.

Fig. 10 shows-a position substantially at the start of bending.

Fig. 11 is a view showing a position substantially at the-end of a bending operation.

Fig. 12 shows a position in the return of the mechanism to the starting position.

Fig. 13 shows a further progressive position in the return movement.

Fig. 14 shows the bending mechanism fully returned to starting position with the tube being advanced.

Fig. 15 is a view similar toFig. 11 but shows the final position of the bending mechanism in forming a bend reverse to that shown in Figs. 9 to 14 inclusive.

An exemplary serpentine coil is generally indicated at I and it comprises a single length of tubing having a plurality of runs 2 with bends 3 at one end or side of the coil and reverse bends 4 at the other end or side. As indicated, the ends of the tube at 5 and 6, lie in the same plane as the outside surfaces of the bends 4. It is to be appreciated, however, that the ends 5 and 8 may, if desired, be displaced from alignment with the bends 4; that one end of the tube may be adjacent the bends 4 while the other may be adjacent the bends 3; that coils may be made with any desired number of runs and bends therein. The tubing from which the coil is made is generally indicated at T in Fig. 2.

The apparatus comprises generally, as illustrated in Fig. 2, a suitable table II) which may be circular in form with the bending mechanism as generally illustrated at H located more or less centrally thereof and a driving unit for advancing the tube is generally illustrated at i2, the support for which includes a frame l3 suitably secured to the table Ill. The structure of the bending mechanism or head, as shown in Figs. 3 and 5, comprises a supporting bearing member or bracket |5 fixedly secured upon a support H5 in which a power shaft I1 is journalled. The power shaft has on its upper end, a head l8 which may rest upon the top of the bracket l5. This head carries two studs or pintles l9 and journalled upon the pintles are grooved forming rollers 28 and 2|. As indicated in Fig. 5, the parts are so proportioned, having reference to the center to center distance between the pintles, the diameter of the forming rollers and the grooves therein, that the tube T may freely enter the same with some lateral clearance. Concentric with the pintles are bearings 20a and 2|a. These in fact, may be enlarged integral parts of the pintles.

The rollers 28 and 2| are positioned with respect to the top of the table so that a tube may be passed between the rollers and the head I8 is arranged to be oscillated on the axis of the shaft H. The means for oscillating the shaft is indicated in Figs. 3 and 4 and resides in a gear'23 on the shaft and a rack 24 reciprocable in a guide 25. There is a suitable lower supporting structure including a plate 26 in which the lower end of the shaft may be journalled and mounted upon this support are guides 21 in which is mounted for reciprocation a cylinder 28. Mounted in a fixed position is a cylinder 29. A piston 38 in cylinder 29 has a connecting rod 3| which is connected to the head of the cylinder 28. A piston 32 in cylinder 28 has a piston rod 33 connected to the rack. Connected to the opposite end of the rack is a rod 34 with an abutment 35 thereon which operates between two stops 36 and 31. These two stops are mounted for adjustment toward and away from each other as by means of a screw 38 with a right hand thread for one stop and a left hand thread'for the other stop. The abutment 35, in operating between the stops 38 and 31, limits the stroke ends of cylinder 29 and suitable control valve means is employed such as four-way valves a and b.

Turning now to the tube feeding mechanism as indicated in Figs. 7 and 8, there is a suitable support 50, which carries a sub-support or frame 5|. This frame is mounted so that it may shift in the direction of extent of the tube, that is, axially of the tube, and so that it may oscillate. To this end, there are devices in the nature of guides 52 secured to the support 58, and mounted on the frame 5| are rocker elements 53. These elements, as shown in Fig. '7, underlie the guides 52 so that they may shift with respect thereto. and they have arcuate surfaces 54 which rock or slide on straight surfaces 55 of the guides 52.

Mounted on the frame 5| in suitable bearings, as illustrated, is a lower driving roller 88 and an upper driving roller 6| between which the tube T is passed. One roller, such as the lower roller, is driven as by means of a chain 82 operating over a sprocket 83. For safety purposes the sprocket is connected to the shaft 64 of the lower roller by a friction clutch held engaged by a spring 65. The rollers 88 and BI are geared together as by means of gears 68 and 81 so that upon the driving of the roller 80, the roller 8| operates in unison therewith. The faces of the rollers which engage the tube are of a soft material such as rubber.

The shaft 64 for the lower roller 60 is in a fixed position. The shaft 10 for the upper roller is mounted in a frame 1| which is pivoted as at E2. Oscillation of this frame serves to raise roller 6| from driving roller 60. To this end, there is a suitable means such as a cylinder I3 mounted on the frame 5|. A piston in this cylinder has a connecting rod 14 connected by suitable linkage 15 to the frame 1| and preferably a spring 18 is interposed to normally elevate the frame II and separate the rollers 60 and BI. By the introduction of fluid, such as compressed air, to the cylinder, through conduit 18, the frame II is pulled downwardly and the tube is gripped between the driving rollers. By the introduction of air under pressure into the cylinder, through line 11, the frame is elevated to lift roller 8| from the tube to thereby free it from the driving action.

This driving unit and the bending mechanism are interassociated by an oscillating bar or swing bar 88. This bar is secured to the drive unit as by means of brackets 8| (Fig. 8), to which the swing-bar is bolted or otherwise secured as at 82. As indicated in Fig. 3, the bar extends at a level just under the table ID to the bending head where it terminates in a sort of fulcrum head or terminal piece 88. Fixedly secured to the bar is a guide pipe 84 for the tube T and this guide pipe lies in a slot 85 in the table. The guide pipe is so positioned that when a tube is lying in the guide pipe, said tube is substantially in a plane for lying upon the surface of the table Ill. The slot 85 in the table is enlarged near the center thereof as shown at 86 for purposes of clearance in the oscillation of the swing bar 80.

The fulcrum head 88 has a form as indicated in Figs. 9 to 15 inclusive, the same being, in effect, an enlarged end of the swing bar 88 and provided with a notch 81 and a notch 88 on opposite sides of its central portion 89 (see Fig. 11). These notches are angularly disposed relative to each other and provide an undercut arrangement relative to the center part 88. As shown in F18. 9, the two notches may be substantially arcuately formed about the center Ila of the shaft H. The

bearing portions 20a and 2la of the pintles I9 and to this end the swing bar 80 lies in a position so that its head 83 lies over the oscillating head I8 (Fig. 5) and under the bending rolls 20 and 2 I.

The structure comprising the drive unit I2 and the swing bar 80 is spring actuated as by means of a coiled tension spring 90 attached at one end to a fixed structural member 9I and attached at its opposite end at 92 to the driving unit (Figs. 3 and 8). The swing bar 80 is strengthened by a reinforcement 94 and depending from the swing bar is a bracket 95, the lower end of which is arranged to abut an adjustable stop 96 to determine the limit position of the swing bar when acted upon by the spring. The stop 96 is ad- I justable by means of the screw 91,

Mounted on the swing bar 80 and positioned for movement in the opening 86 as the swing bar. oscillates is a clamp for the tube. This clamp, as shown in Fig. 6, comprises an inverted U-shaped clamp element I secured to the swing bar by brackets IN and I02. As illustrated in Fig. 3, the clamp is positioned so that as the tube passes out through the guide pipe 80 it passes imme-. diately into the clamp member I00. Movably mounted within the member I00 is a clamp block I03 provided with an extension I04 slidably positioned between the brackets IN and I02. Journalled in the brackets IN and I02 is a rocker shaft I which has an eccentric I06 rotatably positioned in the extension I04 and afiixed to the rock shaft I05 is a yoke I01. There is an air cylinder H0 pivotally mounted at one end to the bracket 95 as at III and it has a piston therein,

the piston rod of which is connected to the yoke I01 as at II2. Shift of the piston in one direction oscillates the yoke and in turn oscillates the eccentric I06 which serves to raise or lower the clamp block I03. the tube is clamped between the block and the member I00 and as the clamp block is lowered the tube is released. The cylinder I I0 hassuitable ports H3 and H4 for the introduction of air under pressure. The purpose of the clamping is to clamp the tube in position which is fixed relative to the former roll during the bending operation. It will be noted by reference to Fig. 6, that the clamp I00 and the clamp block I03 are fashioned with cooperating grooves for engaging around the tube to clamp and center the same. This is at the upstream end of the clamp, In the forward part of the clamp, as shown in Fig. 6a, only the block I03 is grooved. This permits of some lateral movement of the tube in the member I00 when the clamp block is lowered.

As will be appreciated by the foregoing description, the tube is fed forwardly by the rollers 60 and GI at appropriate times, and means are provided to limit this feeding movement. As indicative of a means for this purpose, there is a stop shown at I I5 arranged to project up through the table and it may be elevated and retracted by an air cylinder H6 and into which air may be introduced through a connection H1 and H8. It will, of course, be appreciated that this stop may be located wherever desired depending upon the lengths of the run of the coil.

Before taking up the operation of the machine as a whole, reference should be made to Figs. 9 to 14, inclusive, which show several progressive positions of the bending mechanism in the making of a bend and in return to the starting position. The starting position is shown in Fig. 9 with the tube lying between the rolls 20 and 2| As the clamp block is raisedthe roll 2|.

and with the head of the swing bar centrally located. In this position, the spring 90 holds the swing bar and its head 83 yieldingly forward, that is, in a direction toward the bendingrolls in a position as determined by the stop 96. The head 83, as mentioned above, lies under the rolls 20 and 2| but above the oscillating member I8 so that its notches 81 and 88 are in alignment with the bearingportions 20a and 2 la of the two rolls. The first step is the application of the clamp I00 to the tube so that the tube is clamped firmly to the swing bar. Next, a rotary motion is given to the oscillating head I8, as for example, a clockwise motion as shown by the arrow in Fig. 10, Due to the fact that the tube passes between the rolls with clearance, this clearance or slack is not taken up until the rolls assume the position as substantially shown in Fig. 10. Thus, the rolls are offset and a suitable leverage on the tube is attained, this being the center to center distance between the two rolls measured axially of the tube. At this time, the roll 2I has been shifted substantially to the point where its bearing 2Ia seats in the notch 81. Inasmuch as the bearing 2I a revolves around the center I1a, the notch 81 is preferably formed, as mentioned above, substantial y on an are on the same radius.

Continued movement from the positionshown in Fig. 10 results in a bending of the tube about In this action, the roll 2| acts as a former and the roll 20 acts as a shaper for fashioning the tube around the roll 2|. This movement may continue to a position as indicated in Fig. 11, at which time a. bend of about 180 is accomplished. Now, it will be observed that as the head I8 rotates from the Fig. 10 position to the Fig. 11 position, that a retracting movement of the swing bar 80 is necessary. In other words, the bearing 2Ia, being seated in the notch 81, causes the end of the swing bar 80 to follow the movement of the bearing 2la. This extends the spring 90 and slides the swing bar backwardly. At the same time the driving unit I2 is pushed back and oscillated because it is fixedly united to the swing bar. This movement is accomplished by the sliding of the members 53 and the rocking of 13:1; members 53 relative to their guide brackets The oscillating head I8 is now reversed and it moves in a counter-clockwise direction as illustrated in Fig. 12. This Fig. 12 illustrates a substantial retraction of the swing bar 80 and its head 83 and indicates likewise the position of the same that it necessarily took in a corresponding position in the movement from Fig. 10 to Fig. 11. As the movement continues the parts arrive at a position shown in Fig. 13, this figure corresponding substantially to the position indicated in Fig. 10. However, the swing bar 80 has now been pulled forwardly against its stop and, it is necessary at or before this position is reached to release the clamp I00. This is because the swing bar cannot move forward and in order for the bearing 2Ia to move out of the notch 81, the tube which is bent around the roller 2I, must be released. Therefore, the clamp I00 is opened at about or before the time the parts reach the Fig. 13 position and the parts move back to the starting position shown in Fig. 14. Fig. 14 corresponds to Fig; 9.. This action pulls the tubing forwardly.

In the making of the return movement after a bend has been formed, it is necessary that the tube shift laterally relative to the swing bar and its clamp. This will be appreciated by reference to Fig. 14. The run of the tube which engages the outside surface of the roll 2! hugs the same due to the bend, and if the body of the tube were held centered on the swing bar, the bend would be opened up by a bending action. Accordingly, as shown in Fig. 6, the lateral dimension inside the clamp I is in excess of the diameter of the tube. As a result, when the block I03 is lowered as shown in Fig. 6a the portion of the tube in the clamp may shift laterally. The portion of the tube at the rear of the clamp which lies in the notched formation, shown in Fig. 6, may be held centered, but forwardly of this portion where the underface of the clamp I00 is flat, the tube may shift laterally. There may be a slight flexing of the tube in this function. This situation is due to the fact that the rolls 20 and 2! are spaced apart to provide lateral clearance with respect to the tube as shown in Fig. 5. In other words, the distance from the axis l'la to a diametrically opposite point within the groove of either roller 20 or 2| is greater than the inside cross dimension.

One bend 3 has now been made in the tube and the tube is now fed forwardly to a position as determined by the stop and this is indicated in Fig. 2. The next function is to reverse the movement of the oscillating head l8 from the Fig. 14 position to the Fig. 15 position. The several positions are the same as that shown in Figs. 10, 11, 14 and 13, except reverse. In other words, starting from the Fig. 2 position, the clamp is applied; the head I8 is oscillated counter-clockwise; the bearing 26a. seats in the notch 88 and as this proceeds the final position is indicated in Fig. 15. The rotation is again reversed to move the parts back to the starting position. In this return movement, the clamp I00 is released so that the bearing a may move out of the notch 88 thus pulling the tube with it until starting position is reached. This will be appreciated because bend 4 is fashioned around the roller 20. In making the bend 4 the roller 2|] functions as a former and the roll 2| functions as a shaper to fashion the tube thereabout. Following the fashioning of a bend 4 and the return of the parts to a starting position, the tube is again advanced and the cycle repeated.

The entire apparatus may be set up for an automatic operation, one cycle of Which is substantially as follows: The tube is advanced by the driving unit until the advance is arrested by the stop H 5. After the tube has reached its position the driving rollers 60, 6| may be opened by the introduction of air into the cylinder 13 to thus elevate roller 6i. Air is now entered in the cylinder H0 to apply the clamp to the tube. To oscillate the bending head the double cylinder arrangement 28, 29, shown in Fig. 3, may be employed and let it be assumed that the first bend is to be made by shifting the rack 24 to the left as Fig. 3 is viewed. Air under pressure is introduced into the cylinder 28 through the line 42. At the same time air under pressure is introduced in the cylinder 29 through line 44. This pushes the piston, 32 to the left in its cylinder thus shifting the rack and the reaction for the cylinder 28 is taken by the air in cylinder 29. This movement is stopped by the stop 36. On the return movement, air under pressure is introduced in the cylinder 28 through the line for the next succeeding bend, air is introduced into the cylinder 29 through line 43 and exhausted through line 44 and air is maintained in cylinder 28 through line 4!. This moves the piston 30 to the right and the piston pulls with it the cylinder 28 and its piston 32 until the movement is stopped by the stop 31. For the return movement, air is exhausted from the cylinder 29 through line 43 and entered through line 44 until the parts move back to the starting position. In this return movement, air may be maintained in cylinder 28 through line 4|. As will be appreciated by those skilled in the art, the valves a and b may be of the conventional four-way type operable to admit air under pressure to one end of a cylinder while exhausting the opposite end of the cylinder, and they may be arranged to be automatically operated. The stops 36 and 31 can be adjusted to thus determine the stroke and the angle through which the bends are made. The drawings show bends of 180 but this can be varied.

Accordingly, after the tube has been advanced and clamped the double cylinder arrangement 28, 29 oscillates the bending head to form one bend. In this action, the stop H5 may be retracted so as to not interfere with the swinging of the coil and the driving roll 60 may be elevated by the introduction of air into the cylinder 13. On the return stroke, the clamp, as above set forth, is released and-air is reversed in the cylinder 13 to bring the driving rollers 60, 6| into action and the tube again advanced. The stop I I5, of course, is again properly located to stop the advancement at the proper place. The introduction of the air into the several cylinders for operating the bending head, the clamp, the stop and the driving rolls, is preferably controlled by conventional timing mechanism not shown. In operating the apparatus, lengths of tube of predetermined length are preferably fed to the machine, the lengths being predetermined in acqordance with the requirements of the particular coil being fashioned. As a result, when the trailing end of the tube is projected through the bending rolls by the next succeeding tube, a coil has been completed and is removed from the table.

I claim:

1. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a successiondof reverse bends, comprising an oscillatory head, two bending elements on the head spaced from the oscillating center thereof, said head having a starting position in which the elements lie on opposite sides of the work piecepresented thereto so that the work piece may be advanced between the elements in said starting position, and means for oscillating the head in a four step cycle to wit: (1) rocking movement of the head from the starting position in one direction so that one element bends the work piece about the other element, (2) reverse rocking movement of the head to starting position in which position the work piece may be advanced, (3) rocking movement of the head in the opposite direction so that the said other element bends the work piece about the said one 4|, and exhausted through line 42. In this re- Now, to shift the rack 24 to the right element, and (4) reverse rocking movement of the head back to starting position.

2. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bend, comprising a head mounted for oscillation about a fixed axis, two bending elements on the head spaced from the oscillating center thereof, said head having 9 a starting position in which the elements lie on opposite sides of the work piece presented thereto so that the work piece may be advanced between the elements in said starting position, and means for oscillating the head in a four step cycle to wit: 1) rocking movement of the head from the starting position in one direction so that. one element bends the work piece about the other element, (2) reverse rocking movement of the head to starting position in which position the work piece may be advanced, (3) rocking movement of the head in the opposite direction so that the said other element bends the work piece about the said one element, and (4) reverse rocking movement of the head back to starting position;

3. Apparatus for shaping elongated: work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, com

prising a head mounted for oscillation about a fixed axis, two bending rolls pivotally mounted on the head, said rolls being pivotally mounted on the head at locations spaced from the center of oscillation and substantially diametrically op posite each other, said head having a starting,

position in which the rolls lie on opposite sides the head in a four-step cycle to wit: (1) rockingmovement of the head from'the starting positiori' in one direction so that one roll bends the work piece about the other roll, (2) reverse rocking movement of the head'to starting position in which position the work piece may be advanced, (3) rocking movement of the'head in the opposite direction so that the other roll bends the work piece about the said one roll, and (4) reverse rocking movement of the head in reverse starting position. I

4. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising a head mounted for oscillation about a fixed axis, two bending rolls pivotally mounted on the head, said rolls being pivotally mounted on the head at locations spaced from the center of oscillation 'and substantially diametrically opposite each other, said head having a starting position in which the rolls lie on opposite sides of a work piece presented therebetween so that the work piece may be advanced between the rolls in said starting'position, and means for oscillating the head in a four-step cycle to wit: (1) rocking movement of the head from the starting position in one direction so that oneroll bends the work piece about the other roll, (2) reverse rocking movement of the head to starting position in'which position the work piece may be advanced, (3) rocking movement of the head in the opposite direction so that the other roll bends the work piece about the said one roll, and (4) reverse rocking movement of the head in reverse starting position, said means being arranged and constructed to positively stop the oscillation of the head in its starting position-for step by step advancement of the work piece.

5. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising a head mounted on an axis, two bending elements mounted on the head spaced relative to each other and spaced from the axis of the head, means for feeding work pieces between the bending elements, said head having a starting position for the feeding of the work pieces when the elements are on opposite sides of thework piece, means for oscillating the head in a fourstep cycle to wit: (1) rocking movement of the head from starting position in one direction so that one element bends the work piece about the other element, (2) reverse rocking movement of the head to starting position in which position the work piece may be advanced, (3) rocking movement of the head in the opposite direction so that the other element bends the work piece about the said one element, and (4) reverse rocking movement of the head back to starting posiion, and guide means for the work piece for feeding the same between the elements and arranged to oscillate with the oscillating action of the head. 6. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising a head mbunted on an axis, two bending elements mounted on the head spaced relative to each other and spaced from the axis of the head, means for feeding work pieces between the bending elements, said head having a starting position for the feeding of the work pieces when the elements are on opposite sides of the work piece, means for. oscillating the head in a four-step cycle to wit:},'(1) rocking movement of the head from starting position in one direction so that one element bends the work piece about the other element, (2); reverse rocking movement of the head to starting position in which position the work piece may be advanced, (3) rocking movement of the head in the opposite direction so that the other element bends the work piece about the said one element, and (4) reverse rocking movement ofthe head back to starting position, and clamping means positioned on the upstream side of the head for clamping and holding the work piece against lengthwise movement during the first and third steps of the oscillation of the head.

'7. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising a head mounted on an axis, two bending elements mounted on the head spaced relative to each other and spaced from the axis of the head, means for feeding work pieces between the bending elements, said head having astarting position for the feeding of the work pieces when the elements are on opposite sides of the work pieces, means for oscillating the head in a fourstep cycle to wit: (1) rocking movement of the head from starting position in one direction so that one element bends the work piece about the other element, (2) reverse rocking movement of the head to starting position in which position the work piece may be advanced, 3) rocking movement of the head in the opposite direction so that the other element bends the Work piece about the said one element, and (4) reverserocking movement of the head back to starting position, means for guiding the tube to the head and mounted for oscillation with the oscillation of the head, said guiding means including a clamp for fixedly clamping the work piece on the upstream side of the head during the first and third oscillating steps thereof.

8. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising an oscillatory head, two bending elements on the head disposed in spaced relation and removed from the axis of oscillation, means for feeding tubeto the head and between the two bending elements, means for guiding the tube from the feeding means to the head, the feeding means and the guiding means being connected together and mounted for rocking movement, said head having a starting position in which the bending elements lie on opposite sides of the work piece so that the work piece may be advanced therebetween, means for oscillating the head in a four-step cycle to wit: (1) rocking movement of the head from the starting position in one direction so that'one element bends the work piece about the other element, (2) reverse rocking movement of the head to starting position, in which position the work piece may be advanced, (3) rocking movement of the head in the opposite direction so that the said other element bends the work piece about said one element, and (4) reverse rocking movement of the head back to starting position, and means for interconnecting the oscillatory head and the guide means for causing rocking movement of the guide means and the feeding means with the oscillatory movements of the head.

9. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising an oscillatory head, two bending elements on the head disposed in spaced relation and removed from the axis of oscillation, means for feeding tube to the head and between the two bending elements, means for guiding the tube from the feeding means to the head, the feeding means and the guiding means being connected together and mounted for rocking movement, said head having a starting position in which the bending elements lie on opposite sides of the work piece so that the work piece may be advanced therebetween, means for oscillating the head in a four-step cycle to wit: (1) rocking movement of the head from the starting position in one direction so that one element bends the work piece about the other element, (2) reverse rocking movement of the head to starting position, in which position the work piece may be advanced, (3) rocking movement of the head in the opposite direction so that the said other element bends the work piece about said one element, and (4) reverse rocking movement of the head back to starting position, said guide means including a notched terminal piece and abutments on the oscillatory head for engaging the notched terminal piece as the head oscillates to cause rocking movement of the guide means and feeding means with the oscillatory movements of the head.

- 10. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising an oscillatory head, two bending elements mounted on the head in spaced relationship and eccentric of the axis of oscillation, means for guiding a work piece in between the said elements, means for oscillating the head first in one direction then the other for making opposite bends in the work pieces, said guiding means including a terminal piece with bearing parts thereon, and bearing parts on the head for seating on the bearing parts on the terminal piece as the head oscillates for causing movement of the guiding means incident to oscillation of the head.

11. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising an oscillatory head, two bending elements mounted on the head in spaced relationship and eccentric of the axis .of oscillation, means for guiding a work piece in between the said elements. means for oscillating the head first in one direction then the other for making opposite bends in the work piece, said guiding means including a terminal piece with laterally spaced recesses therein, and bearing means on the oscillatory head arranged respectively to take bearing in one of the recesses as the head oscillates, to shift the guiding means both laterally and axially relative to the direction of extent of the; work piece during oscillation of the head.

12. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising an oscillatory head, two bending elements mounted on the head in spaced relationship and eccentric of the axis of oscillation, means for guiding a work piece in between the said elements, means for oscillating the head first in one direction then the other for making opposite bends in the work piece, means for mounting the guiding means for movement both toward and away from and transverse to the axis of oscillation, said tube guiding means having a terminal piece adjacent the oscillatory head with spaced notches, and bearing means on the head associated with each bending element, one for seating in one notch as the head oscillates in one direction and the other for seating in the other notch as the head oscillates in the opposite direction for causing movement of the terminal piece incident to oscillation of the head.

13. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, com.- prising an oscillatory head, two bending elements mounted on the head in spaced relationship and eccentric of the axis of oscillation, means for guiding a work piece in between the said elements, means for oscillating the head first in one direction then the other for making opposite bends in the work piece, means for mounting the guiding means for movement both toward and away from and transverse to the axis of oscillation, said tube guiding means having a terminal piece adjacent the oscillatory head with spaced notches, and bearing means on the head associated with each bending element, one for seating in one notch as the head oscillates in one direction and the other for seating in the other notch as the head oscillates in the opposite direction for causing movement of the terminal piece incident to oscillation of the head, and a clamp on the guiding means for clamping the work piece as the head is oscillated to bend the same.

14. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising an oscillatory head, two bending elements mounted on the head in spaced relationship and eccentric of the axis of oscillation, means for guiding a work piece in between the said elements, means for oscillating the head first in one direction then the other for making opposite bends in the work piece, means for mounting the guiding means for movement both toward and away from and transverse to the axis of oscillation, said tube guiding means having a terminal piece adjacent the oscillatory head with spaced notches, and bearing means on the head associated with each bending element, one for seating in one notch asthe head oscillates in one direction and the other for seating in the other notch as the head oscillates in the opposite direction for causingmovement of the terminal piece incident to oscillation of the head, and a clamp on the guiding means for clamping the work piece as the head is oscillated to bend the same, said clamp being arranged and constructed to provide for lateral movement of the work piece relative thereto when the clamp is released.

15. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends-comprising an oscillatory head, two bending rolls mounted on the head in spaced relationship and eccentric to the axis of oscillation, means for guiding a work piece in between said rolls, means for oscillating the head first in one direction and then the other for making opposite bends in the work piece, means for mounting the guiding means for a compound movement toward and away from and transverse to the axis of oscillation, a. terminal piece on the guiding means having laterally spaced recesses, a bearing on the oscillatory head concentric to each of the bending rolls, one bearing adapted to seat in one notch as the head oscillates in one direction and the other bearing adapted to seat in the other notch when the head oscillates in the opposite direction for causing theterminal piece to follow the movements of the oscillatory head.

16. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising an oscillatory head, two bending rolls mounted on the head in spaced relationship and eccentric to the axis of oscillation, means for guiding a work piece in between said rolls, means for oscillating the head first in one direction and then the other for making opposite bends in the work piece, means for mounting the guiding means for a compound movement toward and away from and transverse to the axis of oscillation, a terminal piece on the guiding means having laterally spaced recesses, a bearing on the oscillatory head concentric to each of the bending rolls, one bearing adapted to seat in one notch as the head oscillates in one direction and the other bearing adapted to seat in the other notch when the head oscillates in the opposite direction for causing the terminal piece to follow the movements of the oscillatory head, and a clamp on the guiding means for clamping the work piece thereto as the head oscillates to bend the work piece.

17. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising an oscillatory head, two bending rolls mounted on the head in spaced relationship and eccentric to the axis of oscillation, means for guiding a work piece in between said rolls, means for oscillating the head first in one direction and then the other for making opposite bends in the work piece, means for mounting the guiding means for a compound movement toward and away from and transverse to the axis of oscillation, a terminal piece on the guiding means having laterally spaced recesses, a bearing on the oscillatory head concentric to each of the bendof the yielding means so that the bearing means on the oscillatory head are free of the recesses when the center line between the centers of the bending rolls is substantially at right angles to the work piece.

18. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising oscillatory bending means, means for oscillating the bending means first in one direction then the other from a starting position for making bends in the work piece, feeding means for advancing the work pieces, guiding means for guiding the work pieces from the feeding means to the bending means, the feeding means and guiding means being movably mounted as a unit, and inter-engaging means on the oscillating bending means and on the guide means for causing movement of the guide means and feeding means incident to oscillation of the bending means.

19. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising oscillatory bending means, means for oscillating the bending means first in one direction then the other from a starting position for making bends in the work piece, feeding means for advancing the work pieces, guiding means for guiding the work pieces from the feeding means to the bending means, said guiding means and feeding means being connected together as a unit, means for swingably and slidably mounting said unit, and interengaging means on the oscillating bending means and of the said unit for causing sliding and swinging movement of said unit incident to oscillation of the bending 0. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising oscillatory bending means, means for oscillating the bending means first in one direction then the other from a starting position for making bends in the work piece, feeding means for advancing the work pieces, guiding means for guiding the work pieces from the feeding means to the bending means, said guiding means and feeding means being connected together as a unit, means for swingably and slidably mounting said unit, and interengaging means on the bending means and on said guiding means and feeding means unit effective following some oscillatory movement of the bending means from its starting position for causing said'unit to shift slidably and swingably during the remainder of the oscillatory movement in making a bend in the work piece.

21. Apparatus for shaping elongated work pieces, such as tubing, into coils of serpentine form having a succession of reverse bends, comprising oscillatory bending means, means for oscillating the bending means first in one direction then the other from a starting position for making bends in the work piece, feeding means for advancing the work pieces, guiding means for guiding the work pieces from thefeeding means to the bending means, said guiding means and feeding means being connected together as a unit, means for swingably and slidably mounting said unit, interengaging means on the bending means and on said guiding means and feeding means unit effective following some oscillatory movement of the bending means from its starting position for causing said unit to shift slidably and swingably during the remainder of the REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Kilmer Dec. 14, 1880 Number Number Number 16 Name Date Cooper Feb. 2, 1892 Slsson July 30, 1901 Trosiener Aug. 24, 1909 Gail May 10, 1910 Holmgreen Mar. 29, 1921 Skinner July 14, 1925 Mason Aug. 23, 1932 Wesley Aug. 9, 1938 FOREIGN PATENTS Country Date Germany Dec. 3, 1910 France a July 24, 1920

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