US3503236A - Machine for continuous production of an unsupported helix - Google Patents

Description

March 31, 1970 w. 'H. H. MOEBUS 3,503,236

MACHINE FOR CONTINUOUS PRODUCTION OF AN UNSUPPORTED HELIX Filed April 17, 1967 4 Sheets-Sheet 1 FIG.

7e as 84 58 46 so 62 60 l 52 as E BOX MOTOR 7o 3 75 as //v l EN TOR WALTER H. H. MOEBUS AT TORNEV March 31, 1970 w. H. 'H. MOEBUS 3,503,236

MACHINE FOR CONTINUOUS PRODUCTION OF AN UNSUPPORTED HELIX Filed April 17, 1967 4 Sheets-Sheet 2 N W? N TOR WAL TEE H. H. MOEBUS- AT TORNE V March 31, 1970 w. H. MOEBUS 3,503,236

MACHINE FOR CONTINUOUS PRODUCTION OF AN UNSUPPORTED HELIX Filed April 17, 1967 4 Sheets-Sheet 5 FIG. 3

FIG. 4 22 II" FIG. 8 I

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A T TORNEI March 31, 1970 w. H. H. MOEBUS 3,503,236

MACHINE FOR CONTINUOUS PRODUCTION OF AN UNSUPPORTED HELIX Filed April 17, 1967 4 Sheets-Sheet 4 FIG. /0 22 22 Ill I i 28 H 27 I III!" il I Ill //V I/EN TOR WALTER H. H. MOEBUS LAW ATTORNEY United States Patent 3,503,236 MACHINE FOR CONTINUOUS PRODUCTION OF AN UNSUPPORTED HELIX Walter H. H. Moebus, North Plainfield, N..I., assignor to 'Air Reduction Company, Incorporated, New York,

N.Y., a corporation of New York Filed Apr. 17, 1967, Ser. No. 632,150 Int. Cl. B21d 11/00 US. CI. 72-66 7 Claims ABSTRACT OF THE DISCLOSURE A cam with a substantially plane operating surface is arranged to push with different portions of its surface against a helical winding of ribbon or filament on a stationary mandrel supported with one end free, the cam operating in synchronism with a winding mechanism by which the material is laid upon the mandrel in contact with the pushing portion of the cam surface, so that the completed portion of the winding is substantially continuously moved toward and off from the free end of the mandrel. The helical winding is formed of a ribbon of form-retaining material, such as aluminum, cooper, or alloys thereof.

BACKGROUND OF THE INVENTION Field of the invention The invention relates to a method and means for continuously forming an unsupported helical winding from a ribbon or filament of metal or other suitable form-retaining material upon a stationary mandrel free at one end, and for continuously moving the finished winding toward and off the free end.

Description of the prior art Helical windings have been formed from ribbon in a continuous process on a moving mandrel, or on a stationary mandrel, in which latter case the finished winding has been moved along and off from the mandrel by means of screw type guides, comprising one or more turns of screw thread, or in some cases a nearly complete single turn of screw thread.

SUMMARY OF THE INVENTION The invention retains the simplicity of the stationary mandrel while avoiding the complication of a screw-typeguide for removing the finished winding continuously from the free end of the mandrel. The invention employs a cam of simple and inexpensive form, having a substantially plane operating surface. In one embodiment, a cam follower is provided in the form of a lever pivoted in a slot in the mandrel and arranged to be oscillated by the cam in synchronism with the winding mechanism.

In another embodiment an inclined plane cam surface working without the pivoted lever exerts its pushing action continuously around the entirecircumference of the winding, different portions of the cam surface coming into play successively as the cam rotates.

The pivoted lever oscillated by means of a cam, on the other hand, pushes alternately against each of two spaced points on the circumference of the winding, for example the top and bottom. By this means, the winding is kept continuously moving along and off the mandrel. The point of application of the pushing force to the winding remains fixed at one point of the circumference for a time interval, after which the point of application shifts to another position, diametrically opposite the first point.

It will be noted that neither the lever actuated by the inclined plane cam surface nor the cam surface itself is in the physical form of a screw or even of a partial turn of a screw. The lever and the inclined surface of the cam each perform the pushing function, but the form of each is evidently simpler than a screw and may be manufactured more easily to the required precision, it being evident that the flat surfaces of either the lever or the cam are more easily machined than is the curved surface of a screw.

The finished winding has many uses in industry, among them being as fin material in heat exchangers.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view, partly in section, of a machine embodying the invention;

FIG. 2 is an end elevational view of the machine shown in FIG. 1;

FIG. 3 is a diagrammatic representation showing one phase of the operation of laying a ribbon upon a mandrel and against a cam as in the machine shown in FIGS. 1 and 2;

FIG. 4 is a diagram similar to that shown in FIG. 3 but at a phase of operation one-quarter turn of the cam subsequent to the phase shown in FIG. 3;

FIG. 5 is a diagram representing a phase of operation one-quarter turn of the cam subsequent to the phase r shown in FIG. 4;

FIG. 6 is a diagram representing a phase of operation one-quarter turn of the cam subsequent to the phase shown in FIG. 5;

FIG. 7 is an enlarged detailed showing, partly in section, of a cam and following lever pivoted in a slot in a mandrel, with the cam surface perpendicular to the plane of the paper;

FIG. 8 is a view similar to that shown in FIG. 7, with the cam turned a quarter turn from its position as shown in FIG. 7;

FIG. 9 is a diagram similar to that shown in FIG. 3 but with a pivoted lever inserted between the cam shown in FIG. 3 and the ribbon being wound on the mandrel;

FIG. 10 is a diagram similar to that shown in FIG. 9 but at a phase of operation one-quarter turn of the cam subsequent to the phase shown in FIG. 9;

FIG. 11 is a diagram representing a phase of operation one-quarter turn of the cam subsequent to the phase shown in FIG. 10;

FIG. 12 is a diagram representing a phase of operation one-quarter turn of the cam subsequent to the phase shown in FIG. 11; and

FIG. 13 is an end view of a twisted mandrel shown in elevation in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, there is shown a first embodiment comprising a spool 20 on which is stored a quantity of ribbon 30, for example thin metal which is capable of being wound into a more or less self-supporting helical winding by laying the ribbon upon a mandrel and bending the ribbon to conform to the cross-sectional shape of the mandrel as the ribbon is laid. A stationary mandrel 24 is shown, supported in a horizontal position with one end fastened to a vertical plate 34, which is in turn fastened to a horizontal base plate 36, the other end of the mandrel being free.

The spool 20 is captively mounted upon a drum 48 upon which later the spool is rotatable. The ribbon 30 is fed over a fairlead roller 32 attached to the drum 48 by a bracket 50, thence over a guide roll 52, to the free end 54 of the mandrel 24, where the winding takes place.

The drum 48 has attached thereto or integral therewith a cam 22 having an operating cam surface 25 which is preferably simply a plane surface inclined to the central axis of the cam. The cam 22 surrounds with slight clearance a cylindrical portion 56 of the mandrel 24 so that there is relative rotary motion between the cam and mandrel.

The free end 54 of the mandrel 24 extends to the left as viewed in FIG. 1 beyond the left-hand end of the cam 22 to receive the ribbon 30. The portion of the mandrel 24 intended to receive the ribbon may be formed into any desired cross-section in order to determine the shape of the finished winding. As illustrated, the mandrel is shaped to produce a Winding of rectangular or oval cross-section, but other shapes may be used, for example hexagonal or circular. If necessary, to prevent a thin ribbon from becoming snagged in the clearance space between the mandrel 24 and the cam 22, a thin washer 66 may be placed over the mandrel, which washer Will be held against the surface 25 of the cam 22 by the ribbon 30 being wound. The opening of the washer should be shaped to fit the cross-sectional shape of the end portion 54 of the mandrel with just suflicient enlargement of the opening to permit the washer to move relative to the non-ircular portion of the mandrel so that said washer remains fiat against the surface of the cam.

The drum 48 is driven by a motor 46 through a gear box 58, a shaft 60, a pinion gear 62, and a ring gear 64, the latter being attached to or integral with the drum 48.

In the operation of the arrangement shown in FIGS. 1 and 2, the drum 48 and cam 22 are rotated as a unit, the fairlead 32 circling the mandrel 24, winding the ribbon 30 about the mandrel, and bending the ribbon to conform with the cross-sectional shape of the mandrel at the point at which the ribbon is applied. Provision is made for maintaining a satisfactory degree of tension in the ribbon as it is applied to the mandrel in order to assure proper bending of the ribbon as it is wound. For this purpose there is illustrated a brake 68 fastened to the drum 48 and bearing upon an edge of the spool 20 as shown. The brake 68 comprises nylon buttons 70, 72 on either side of the spool edge, supported by a bracket 74 attached to the drum 48. The button 72 is attached to a set screw 75 by means of which latter the drag of the brake 68 can be adjusted to provide any desired degree of tension in the ribbon 30.

To start the process, a few turns of the ribbon 30 can be hand wound upon the mandrel 24, whereupon the motor 46 may be started and the operation will then continue automatically. Any length of finished winding can be made as required as long as there is a supply of ribbon on the spool 20. The spool 20 can be replaced by another spool and the new ribbon can then be attached as by soldering to the end of the old ribbon and the process continued without a break in the finished winding.

FIGS. 3-6 show the relationship of the ribbon 30, mandrel 24 and cam 22 at successive phases of operation of the machine shown in FIGS. 1 and 2.

FIG. 3 shows the phase of operation in which the active portion of the working surface of the cam 22 is substantially a horizontal diameter bearing against the side portions of the winding on the mandrel and is ready to push the winding toward the left and off the free end of the mandrel. In this phase, the ribbon 30 extends downward from the guide 52 and is being laid against the forward face of the mandrel 2-4, the forward face being the face closest to the viewer in FIG. 3. The direction of winding is indicated by an arrow 27.

FIG. 4 shows the cam surface a quarter turn later when the surface 25 is perpendicular to the plane of the paper and is inclined downwardly to the left. In this phase, the ribbon 30 extends toward the viewer from behind the plane of the paper and is being laid upon the upper portion of the mandrel 24. The active portion of the cam surface is substantially the diameter in the plane of the paper.

'FIG. 5 shows the cam surface a quarter turn later when the surface 25 is hidden from view, the active portion again being substantially a horizontal diameter bearing against the side portions of the winding, the rear end of the diameter being ready to push the winding toward the left. In this phase, the ribbon 30 extends upwardly from the guide 52 and is being laid against the rear face of the mandrel 24.

FIG. 6 shows the cam surface 25 a quarter turn later when the surface is perpendicular to the plane of the paper and is inclined downwardly toward the right. In this phase, the ribbon 30 extends toward the plane of the paper and is being laid upon the lower portion of the mandrel 24. The active portion of the cam surface is substantially the diameter in the plane of the paper.

After the phase shown in FIG. 6 the system returns to the phase shown in FIG. 3 and the series of phases repeats indefinitely.

In cases where hard ribbon materials are used, which, due to their elastic quality, may tend to unwind to some extent after being pushed off the mandrel, some degree of over-bending is necessary in order to obtain the desired product.

In order to over-bend the ribbon as it is pushed along the mandrel, the free end portion of the mandrel may be twisted, as viewed from the free end 54 in FIG. 13. By carefully selecting the degree of twist of the mandrel, it can be arranged that the finished winding will spring back from the over-bent state as it leaves the free end of the mandrel, so as to assume the shape of a substantially straight helix. The twist is gradual over the portion of the mandrel upon which the winding is applied so that the over-bending is accomplished gradually.

In a second embodiment, which is preferable in case the ribbon 30 is so fine that snagging may occur in the necessary clearance space between the washer 66 and the mandrel 24, the washer is omitted and the cam 22 is used to oscillate a lever 26 mounted on a pivot 28 set in a slot 38 in the mandrel 24, as shown in FIGS. 7 and 8.

The operation of the lever 26 in propelling the finished winding along the mandrel 24 toward and off from the free end thereof is illustrated schematically in FIGS. 9-12, which correspond to FIGS. 3-6 described above in connection with the operation of the embodiment in which the cam surface 25 through the intermediary of the washer 66, if required, serves to perform the pushing or propelling function.

To facilitate winding of the ribbon upon the mandrel, the lever may have working surfaces 101 and 102 which meet at an obtuse angle adjacent to the pivot 28. The surfaces 101 and 102 are preferably substantially planar.

FIG. 9 shows the lever 26 in the vertical position with the ribbon 30 extending downwardly from the guide, 52 and being laid upon the front side of the mandrel 24. The right-hand or trailing edge of the ribbon 30 is in contact with the bottom left-hand edge of the lever 26 which is pushing the bottom portion of the finished winding along the mandrel 24 toward the free end of the mandrel at the left as indicated by an arrow 29.

FIG. 10 shows the situation later in time by one-quarter turn of the cam 22. The finished winding has been moved to the left sufficiently so that there is room for the ribbon to be laid with its right-hand edge in contact with the top left-hand edge of the lever 26. The lever 26 is at the turn-about point where it is ready to start pushing the top portion of the finished winding to the left. The ribbon is extending in a substantially horizontal direction, coming from the ribbon guide 52 toward the viewer.

FIG. 11 shows the situation later in time by another quarter-turn of the cam 22. The lever 26 is in the middle of a pushing stroke, pushing the top portion of the winding to the left as indicated by an arrow 31. The ribbon 30 is being laid upon the front side of the mandrel 24 and is extending upwardly from the ribbon guide 52.

FIG. 12 shows the situation later in time by still another quarter-turn of the cam 22. The finished winding has been moved to the left sufficiently far so that there is room for the ribbon to be laid with its right-hand edge in contact with the bottom left-hand edge of the lever 26. The lever 26 is again at a turn-about point. This time it is ready to start pushing the bottom portion of the finished winding to the left. The ribbon is extending in a substantially horizontal direction, going from the ribbon guide 52 into the plane of the paper away from the viewer and passing under the mandrel 24.

Another quarter-turn of the cam 22 brings the situation back to that shown in FIG. 9, except that the entire finished winding has now been moved one complete ribbon width to the left. The process then repeats itself indefinitely, eventually pushing the forward portion of the finished winding off from the free end of the mandrel 24, producing an unsupported helical winding.

In the phase of the operation shown in FIG. 9, the guide 52 is directly above the mandrel, but not shown in the figure.

Correspondingly, in the case of FIG. the position of the guide 52 is behind the mandrel; in the case of FIG. 11, directly below the mandrel; and in the case of FIG. 12, in front of the mandrel.

FIGS. 7 and 9 represent one and the same phase of operation, as do also FIGS. 8 and 10. FIGS. 7 and 8 are plan views, partly in section, While FIGS. 9 and 10 are elevational views.

The length of the travel path of the pushing edge of the lever 26 is adjusted to match the desired pitch of the finished helical winding by the proper selection of the angle of inclination between the cam surface and the central axis of the cam 22. The pitch may be just sufficient to accommodate the successive turns of ribbon side by side, or, if desired, the pitch may be increased in order to provide separation between successive turns.

Adjustable tabs 76 are provided for holding the spool captive upon the drum 48 and easily removable therefrom for replacing an empty spool or for substituting one spool for another as when changing from one style of ribbon to another. The tabs 76 may be fastened by means of screws 78 so that the tabs project into an annular groove 80 in the drum 48.

The drum 48 is supported upon the plate 34 by a plurality of rollers 82, illustrated as six in number, although more or fewer rollers may be used. The rollers 82 bear upon a flanged track portion 84 on the exterior surface of the drum 48, which track portion serves to maintain the proper clearance between the cam 22 and the mandrel 24 as well as to hold the drum '48 captive with reference to the plate 34.

The guide roll 52 is mounted upon a sector plate 86 pivoted at '88 to the drum 48 so that the position of the roll 52 can be adjusted about the pivot. The plate 86 can be fastened in any desired position by means of a slot 90 and a pin 92. The spacing of the roll 52 from the plate 86 can be adjusted by means of a screw 94 and a nut 96 by which the roll 52 is fastened to the plate 86. The adjustments of the position of the roll 52 are provided so that the angle of the ribbon at the point at which the ribbon is laid against the mandrel can be adjusted optimally. It is usually desirable that the angle of approach of the ribbon be the same as the angle of inclination of the cam surface 25 to the central axis of the cam 22.

Ribbons of various materials may be used in practicing the invention and may be hard or soft, provided they are capable of retaining a suitable bend in the winding process. The shape of the ribbon may be flat, round or otherwise, and the winding may be applied flat upon the mandrel, or standing edgewise upon the surface of the mandrel.

While illustrative forms of apparatus in accordance with the invention have been described and shown herein, it will be understood that numerous changes may be made Without departing from the general principles and scope of the invention.

I claim:

1. Apparatus for producing a helical winding, said apparatus comprising, in combination, a stationary mandrel supported with one end free, rotatable means to wind a ribbon of form-retaining material upon said mandrel to form a helical winding thereon, pushing means in contact with said ribbon, at least a portion of said pushing means being rotatable in synchronism with said winding means, said pushing means comprising a cam having a substantially flat working surface and an inner surface, said cam being mounted concentrically with the mandrel and having said working surface inclined to the central axis of the mandrel, a clearance space between the outer surface of the mandrel and the inner surface of the cam, means comprising a flat washer fitting over the mandrel and held against the working surface of the cam by the ribbon being wound to substantially prevent the ribbon from snagging in said clearance space, said washer having a hole to accommodate the mandrel, said mandrel having a non-circular cross-section when taken on a plane substantially perpendicular to the axis of the mandrel, and said hole being sufiiciently large to permit relative movement between the washer and the mandrel.

2. Apparatus for producing a helical winding, said apparatus comprising, in combination, a stationary mandrel supported with one end free, rotatable means to wind a ribbon of form-retaining material upon said mandrel to form a helical winding thereon, and pushing means in contact with said ribbon, at least a portion of said pushing means being rotatable in synchronism with said winding means, said pushing means comprising a member having a substantially flat working surface, a lever mounted in a slot in said mandrel, together with means including said surface to oscillate said lever.

3. Apparatus according to claim 2, in which the portion of said mandrel upon which the winding is formed is elongated in cross-section.

4. Apparatus according to claim 3, in which said lever extends through said mandrel in a direction substantially parallel to the longer dimension of said elongated crosssection.

5. Apparatus according to claim 2, in which said lever is pivoted substantially at the central longitudinal axis of the mandrel.

6. Apparatus according to claim 2, in which said means to oscillate said lever is a cam.

7. Apparatus for producing a helical winding, said apparatus comprising, in combination, a stationary mandrel, rotatable means to wind a ribbon of form-retaining material upon said mandrel to form a helical winding thereon, a lever contacting said ribbon and pivotally mounted on said mandrel for oscillatory movement about an axis substantially perpendicular to the longitudinal axis of the mandrel, cam means engaging said lever causing said oscillatory movement.

References Cited UNITED STATES PATENTS 2,072,284 3/1937 Voorhees 7266 X 1,396,197 11/1921 Hansen 7266 1,204,970 11/1916 Gilson 7266 1,334,787 3/1920 Palmer 7266 2,467,227 4/1949 Potter et a1. 72142 X 2,431,928 12/1947 Garreau 72139 X CHARLES W. LANHAM, Primary Examiner ANDREW L. HAVIS, Assistant Examiner US. Cl. X.R.

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