US1993883A - Method of drawing tubes - Google Patents

Description

March 12, 1935.

4. HEDDON METHOD OF DRAWING TUBES Filed Dec. 29, 1953 Patented Mar. l2, 1935 I I UNITED STATES PATENT OFFICE LIETHOD OF DRAWING TUBES John Heddon, Dowagiac, Micln, assignor to James Heddons Sons, Dowagiac, Mich, a corporation of Michigan Application December 29, 1933, Serial 704375 R S S U E D 1 Claim. (Cl. 80-62) The method of the present invention is dethe tip joint, which is objectionable, in that it signed primarily to meet the requirements in results in a piling up of the strain at that point, the tapering of drawn tubular fishing rods, alwith the resultant liability of breakage. These though the principles involved are applicable considerations are of particular importance in 5 to the drawing of tubular steel golf shafts or such a light anddelicate instrument as a fly 5 the like or other shafts in which it is desirable to rod, although they are of" lesser importance in produce a tubular shaft having a certain prethe case of short bait casting rods. determined ratio between wall thickness and The method of the present invention is detaper, and particularly in cases in which it is signed to conform to the above considerations essential in the taper product thatthe wall thickand to permit the distribution of the metal in 10 ness at the end of lesser diameter shall not be ratio to taper to be computed with precision, so in excess of the wall thickness at the end of that by the use of the present invention, fly rods greater diameter. of the utmost delicacy can be manufactured which The taper drawing of a tube has the effect of will have all of the lightness and feel of the finer redistributing the metal and crowding it toward bamboo castmg rods and at the same time will 15 the end of lesser diameter, with the result that possess greater elements of strength and duraduring the tapering operation the thickness of bility. I the walls of the tube will be progressively in- The method of the present invention maybe creased as the external diameter of the tube is practiced with machines or appliances of the progressively decreased, with the result that if character particularly set forth and described in 20 the intended product, such for instance as a the Barnhart patent, No. 1,711,825 issued May 7, fishing rod, is drawn from a tube of uniform diam-.- 1929, so that it is not deemed necessary herein to star and uniform wall thickness, the completed describe the mechanism in detail, although refrod or the like will progressively increase in wall erence is had to the accompany drawing, wherethickness toward the tip end, so that the ratio in, of weight to diameter will be greater in the tip Figure 1 is a diagrammatic sectional represenof the rod than in the butt of the rod, which is tation of a tube passing through drawing rollers objectionable in the designing of certain types at the beginning of the drawing operation; of fishing rods, and particularly in the designing Fig. 2 is a view showing a completed tube in of light rods intended for fly casting. which the drawing operation results in a contin-' 30 In the case of a fiy casting rod, or other rods nous taper with progressive decrease in wall in which the question of balance or feel is thickness throughout; and v of primary importance, it is desirable that the Fig. 3 is a similar view in which the drawing wall thickness toward the tip end shall prooperation results in a tube having uniform taper gressively decrease as the exterior-diameter deand uniform wall thickness throughout. 35 creases, or in any event that it shall not increase It will be understood that the present drawing as compared with the wall thickness at the is intended merely as. diagrams, and that the butt end of the rod. In such rods the tip lightwall thickness and ratio of length to diameter ness should be in direct proportion to the (11- is diagrammatically indicated rather than illuslO mension of the-diameter, and such lightness of trated, in order to better bring out the principles tip is particularly desirable on relatively long of the present invention.

rods of the fly casting type, since an increase in In practicing the method of the present inwall thickness toward the tip will so distribute vention, I first start with a tube A of uniform the metal as to impart a feeling of tip heaviness exterior diameter, but tapered on the interior to the rod in the hands of an expert user. Such in order to provide a progressively decreasing considerations, of course, do not apply to certain wall thickness from' the prospective butt end more rugged types of rod, in which an increase of the rod toward the prospective tip end. For in strength toward the tip end is peculiarly depurposes of illustration, it may be assumed that sirable rather than delicacy in the distribution the tube in question; at the thicker end, possesses 0 f W ht. a wall thickness of .010 in. and at the opposite 50 Furthermore, it has been found that in the end a thickness of .005 in., and the initial length testing of fly rods that an increase of the wall of the tube will, of course, be such as to permit thickness in the tip region of the rod has a of its being drawn to the intended length of a tendency to throw an unequal load or strain fishing rod or the like of the intended weight toward the larger and thinner walled end of in the completed rod or rod section.

The tube in its initial form, having uniform exterior diameter and interior taper, is of a character which is being produced at the present time by tube drawing mills in conformity with well understood principles, but the subsequent drawing of the tube to produce a fishing rod of the character previously described is in conformity with the principles of the present invention.

In the tapering operation now to be described, a tube of uniform diameter and interior taper is introduced between rolls B keyed upon shafts C, each roll being provided with a progressively deepening groove D, the formation of the groove being computed to impart the desired progressive taper to the tube in ratio to the speed of advance of the tube through the rolls. Such taper may be uniform throughout or computed in varying ratio within different portions of the tube, or some portions of the tube may be tapered and other portions uniform, depending upon the depth of. the roller groove around different portions of its periphery, in conformity withthe principles set forth and described in the Barnhart patent, No. 1,711,825.

In advancing the tube through the rolls, the tube is drawn forward by a comealong or the like, which is operated in timed relation to the rotation of the rolls which preferably rotate in opposite relation to the advance of the tube, as indicated by the arrows in Figure 1, so that the exterior taper imparted to the tube will at all times be determined by the configuration of the roll grooves in ratio to the speed of advance of the tube relatively to the rotation of the rolls.

As the tube advances under the drag of the comealong, the metal will be drawn back or crowded rearwardly as the tube is elongated, and the wall thickness will be progressively increased during the operation, with the result that after the tube has been drawn into the form of a rod section or the like, the desired exterior taper will be secured in conjunction with the'desired ratio of wall thickness, so that by starting with an initial wall thickness less than the intended resultant wall thickness in the reduced end of the rod, it is possible to build up the wall thickness to the desired degree, which may be less than or equal to the wall thickness at the opposite end of the larger diameter, which latter end may retain its initial wall thickness and diameter in the completed rod. The present process may also, if desired, be employed to provide an increased resultant wall thickness at the end of lesser diameter, although the present invention is designed primarily for use in those cases in which it is desired to decrease the wall thickness concurrently with decrease in ex- ,terior diameter. I

In Fig. 2 I have diagrammatically indicated a rod section having a resultant wall diameter of .010 in. at the butt end and .007 in. at the tip end; and in Fig. 3, a rod section in which the resultant wall thickness is the same-.010 at each end of the section.

In tapering the tube, beginning at the heavy end, it will be understood that I drag less metal as the taper progresses and the tube is elongated in the tapering process, which fact permits of a redistribution of the metal in such a way as to produce uniform wall thickness throughout, or a thinner wall at the end of smaller diameter as compared with the wall thickness at the end of larger diameter, thereby imparting extreme flexibility and lightness in the tip region.

Another feature of importance in connection with the present invention involves the provision of greater strength at or near the ends of the joint where the ferrules are located and which are the points of increased liability to breakage due to the fact that the rod is made inflexible by the natural stiffness or resistance of the ferrules, which prevent a symmetrical yielding or bending of the rod over its entire length when the rod is under strain. This circumstance indicates that the symmetrical resistance to strains should not be less but preferably more immediately adjacent to the ferrules.

Thus by employment of the present invention, it is found that a tube having a wall thickness of .010 in. at one end may be employed, while formerly, by conventional methods of drawing, it was necessary to employ a tube having a lesser thickness of .007 in., which limitation in the past was due to the fact that the use of a thicker tube would result in an objectionably heavy tip joint as a whole.

By the use of the present invention, a tube which initially varies in wall thickness from .010 in. down to .005 in. may be tapered in such a way that the weight of the section as a whole will, when completed, be no greater than a tube drawn from a tube having an initial wall thickness of .007 in. throughout its entire length. In other words, without increasing the weight of the section as a whole, it is possible to start with a wall thickness of .010 in. at the end of larger diameter where strength is most required, and at the same time secure the desired distribution of wall thickness and weight throughout the entire length of the rod section. This is a very important result, since it is con-- ducive to a proper distribution of resistance to strain either in a fine fly rod or in an extreme- 1y flight, flexible and long bait casting rod.

Although the invention has been described with particular reference to the requirements of fishing rods, it is not the intention to limit its' use thereto, since other tubular products may be drawn and tapered in accordance with the principles of the present invention.

I claim:

The method of fabricating a flexible metallic tubular structure, which consists in first producing a tube having a uniform external diameter and tapered on the interior to afford a tapering wall thickness and in thereafter advancing the tube through dies with a resultant elongation and redistribution of the metal to afford an exterior taper by progressive reduction of the exterior diameter toward the end initially having the lesser wall thickness and a progressive increase in wall thickness toward the end whose exterior diameter is being reduced as compared with the initial wall thickness of the corresponding region.

' JOHN HEDDON.

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