US2792050A - Apparatus for manufacturing helically finned tubes - Google Patents

Description

May 14, 1957 R. c. EDWARDS APPARATUS FOR MANUFACTURING HELICALLY FINNED TUBES Filed July 24, 1953 IN VEN TOR.

RAY QEDWARDS A w El APPARATUS FOR MANUFACTURING HELICALLY FINNED TUBES Ray C. Edwards, Pompton Plains, N J.

Application July 24, 1953, Serial No. 370,041

1 Claim. (Cl. 153-645) This invention relates to apparatus for manufacturing helically finned tubes by winding upon a tube a finforming metal ribbon. In convector heating systems and analogous heat transfer systems, in order to obtain maximum heat transfer from the heating tubes to the area to be heated, it is desirable to provide within the limits of said conductivity maximum heat radiation surfaces on the finned tubes employed for conveying the heating medium. However, with tube finning apparatus heretofore available it has been impossible to reach this desirable goal due to the fact that only limited width of metal ribbon could be wound and effectively maintained upon the tube due to its flexibility and thickness of the ribbon and the inability to sturdily maintain relatively wide metal ribbon during the winding operation.

The present invention provides apparatus whereby fins having a width approximately one-third greater than the diameter of the tube may be wound on a tube and effectively maintain in position against buckling, undesirable twisting, etc., during the winding operation and whereby all fins will be accurately maintained in position during and after winding upon a tube, thus providing finned tubes having greatly increased radiation surface over finned tubes heretofore available.

The present invention is an improvement upon the apparatus for manufacturing helically finned tubes disclosed in my prior Pat. No. 2,635,571, issued April 21, 1953, whereby the apparatus of that patent embodying the improvement of the present invention may be employed to manufacture finned tubing having greatly increased radiation surface over finned tubes manufactured by the apparatus without the improvement and by other known apparatus for such manufacture.

With these and other objects in view, as may appear from the accompanying specification, the invention consists of Various features of construction and combination of parts, which will be first described in connection with the accompanying drawings, showing apparatus for manufacturing helically finned tubes of a preferred form embodying the invention, and the features forming the invention will be specifically pointed out in the claim.

In the drawings:

Figure 1 is a fragmentary side elevation of the finned tube manufacturing apparatus showing the present invention applied thereto.

Figure 2 is an end view of the structure shown in Figure 1.

Figure 3 is a fragmentary section through the apparatus taken on the line 3-3 of Figure 1.

Figure 4 is a longitudinal section through the apparatus shown in Figure 1 and taken on the line 4-4 of Figure 2.

Since the present invention relates specifically to the mechanism of the apparatus for manufacturing helically finned tubes disclosed in my prior Pat. No. 2,635,571, issued April 21, 1953, which relates to the winding of the crimped helical fin of a helically finned forming ribbon upon the tube and the ironing out of the crimps on the nited States Patent outer perimetrical portions of such fins the entire mechanism for manufacturing the tubes is not illustrated in the drawings and will not be described herein, it being understood that the metal ribbon crimping mechanism, driving mechanisms to provide rotation of the elements involved in the present invention, the bonding mechanism, etc, may in the present invention be that either employed in the said Letters Patent or any other suitable mechanism to provide the functions.

in the present invention, like in my prior patent the metal tube 1 upon which the thin metal ribbon indicated at 2, which has been previously crimped crosswise throughout its entire width, is helically wound to provide radiating fins on the tube which passed through the fin winding and ironing head structure 3. As described and shown in my prior Patent No. 2,635,571, the fin winding and ironing head 3' embodies means for rotating the tube 1 and advancing it longitudinally through the head 3 as the metal ribbon is wound thereon. The fin forming metal ribbon 2, which as stated above has been previously crimped in laterally extending substantially parallel crimps throughout its entire width is guided by suitable means (not shown) to the head 3 where it is engaged between, in the present instance, a pair of ironing rollers 5 and an anvil 6. The anvil 6 is rotated by a hollow shaft 6 on which is mounted the sheave 4' of the power transmitting mechanism 4, and is provided with an axial bore through which the tube 1 projects. The outer fin engaging face 7 of the anvil 6 is recessed for a predetermined distance outwardly of its axis as shown at 8 so that the portion of the metal ribbon 2 which directly passes this recessed portion will not have the crimps ironed therefrom. Thus, the inner edge portions of the fins indicated at 9 will provide crimped edgewise engagement with the tube 1 to facilitate the stabilization of the fins in their contact with the tube.

The present invention is provided for permitting the winding of fins of relatively great width on the tube with the respective fins which have previously been wound upon tubes to provide finned heat transfer tubes. The finned tubes of the present invention are particularly of advantageous use in convection heating systems wherein a heating fluid such as hot water or steam is circulated through the tubes to heat the ambient atmosphere such as in the heating of homes, rooms or other enclosures where the fins themselves are not subjected to flow of fluid stresses and where it is particularly desirable to provide a maximum heat transfer surface and the metal ribbon employed for forming the fins in the present application has a width approximately one-third greater than the diameter of the tube.

With all of the known types of apparatus for winding metal fin forming ribbon helically upon a tube and in edgewise engagement therewith it is impossible to wind such wide tubes and effectively maintain the tube in position against buckling, undesirable twisting, etc., during the Winding and crimp ironing operation. The present invention provides a mechanism performing this operation by the employment of two ironing rollers 5 and 5a, the axes of which are disposed substantially at angles of to each other and at angles of 45 with respect to a vertical plane bisecting the axis of the tube 1. The axes of rotation of the two ironing heads 5' and 5a are inclined at acute angles to the axis of the tube 1 and converge towards the axis of the tube 1 as clearly shown in Figures 1 and 2 of the drawings. The ironing rollers 5' and 5a are carried by stub shafts 11 which are rotatably supported by suitable bearings 12 on the head 3. The shafts 11 are rotated by means of gears 13 which mesh with a gear 14 carried by the block 3. The shafts 11 are spring tensioned by means of springs 15 to urge the inner angled metal ribbon ironing surfaces 16 of the ironing rollers 5 and 5a towards the ironing face 7 of the anvil 6 and so as to press the metal ribbon 2 against the ironing face of the anvil 6 to iron out the crimps on the outer portions of the fins 9 as they are wound upon the tube. Due to the width of the metal ribbon it has a tendency to buckle or twist during this ironing and winding operation and to prevent such twisting and buckling of the ribbon and to insure the proper ironing out of the crimps in the outer portions of the fins a fin retarding finger 20 is provided which is attached to the head 3 by means of an attaching bracket 21. The retarding finger 20 is in the form of a fiat piece of metal comprising the attaching portion 23 and the curved finger 24 which has an inner concave edge curved to conform to the curvature of the outer surface of the tube 1 is clearly shown in Figure 2 of the drawings. The finger 20 extends parallel to the ironing face 7 of the anvil 6 and engages the surface of the metal ribbon as it is being wound upon the tube opposite to the surface which is engaged by the anvil 6. The retarding finger 20 serves the dual function of staying and stabilizing the inner portion of the fin during the winding and ironing operation and serves to retard the advancement of the fin until it has been engaged by both of the ironing rollers 5' and 5a, thus preventing any buckling or twisting of the fin during the interim between its engagement by the two ironing rollers. The fin engaging side of the finger 20 is also parallel to the successive ribbon engaging portions of the angled ribbon ironing surfaces 16 of the ironing rollers as is clearly shown in Figure 4 of the drawings.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that they may be widely modified within the invention defined by the claim.

What is claimed is:

Apparatus for manufacturing helically finned tubes embodying means for rotating a tube and means for winding a laterally crimped fin forming metal ribbon helically about a tube in edgewise engagement therewith including a fin winding and ironing head embodying a frame, an ironing anvil carried by said head and provided with an opening through which the tube passes, a pair of ironing rollers rotatably carried by said head and arranged in spaced relation to engage the crimped metal ribbon in sequence and cooperating with said anvil to iron out the crimps in the outer edge portion of the metal ribbon as it is wound on the tube, means for rotating said ironing rollers, said anvil having a portion of its metal ribbon engaging face recessed to prevent ironing out of the crimps in the metal ribbon near to its tube engaging edge, and a retarding finger curved to substantially conform to the curvature of the circumference of the tube carried by said frame and held stationary relative to the rotation of said ironing rollers, said finger positioned to engage said metal ribbon near its inner tube engaging edge and on the face of the ribbon which is opposite to the recessed portion of said anvil and which is traveling between said pair of ironing rollers to retard the advancement of the fins until the fins forming ribbon has been rolled against the anvil by both of said ironing rollers.

References Cited in the file of this patent UNITED STATES PATENTS

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