US2535470A - Method of flaring tubing - Google Patents

Description

Dec. 26, 1950 .1. R. wELsHMAN METHOD 0F' FLARING TUBING Original Filed Nov. 1l, 1943 I N V EN TOR.

Jam es E. Wels/nan JOC- Patented Dec. 26, 1950 METHOD F FLARING TUBING James R. Welshman, Cranston, R. I., assigner to Grinnell Corporation, Providence, R. I., a corporation of Delaware Original application November 11, 1943, Serial No. 509,931, now Patent No. 2,437,285, dated March `9, 1948. Divided and this application February v26, 1948, Serial No. 11,120

This invention relates to improvements in a method of flaring tubing. More especially it has to do with the formation of a tapering flared portion at the end of tubing so that the tubing may be engaged by a flared tting.

My improved method is particularly adapted for flaring tubing which has Aa weak longitudinal seam, or similar longitudinal weakness, likely to produce a split in the tube wall when an attempt is made to flare the tubing in the usual manner with the means customarily employed.

It is an object of my invention to provide a method of aring such tubing without rupture of the tube Wall and to provide simple but highly effective apparatus for practicing the improved method.

The best mode in which I have contemplated applying the principles of my invention is described in the following text and shown in the accompanying drawings but the latter are to be deemed merely illustrative for it is intended that the patent seall cover by suitable expression 'in the claim whatever Vfeatures o1 patentable novelty exist in the invention disclosed.

In the accompanying drawings,

Figure l is anexploded view of the several Vparts of a preferred form of apparatus for flaring tubing in accordance with my improved method;

Figure 2 is a medial section showing the parts of ney improved apparatus and a piece of tubing in the relative positions they Yoccupy when the flaring operation is about to be performed;

Figure 3 is a section on line 3-3 of Figure 2;

Figures 4, '5 and 6 show the tubing and immediately adjacent parts of the apparatus in their relative positions at different stages of the flaring operation;

Figure 7 shows the end of the tubing as it generally appears when removed from the apparatus; and

Figure 8 shows the finished ared end.

The essence of my improved method resides in holding the external surface of a portion adjacent the end of the tubing to a diameter less than the greatest diameter of the external surface of the flared portion of the tubing. The thickness of the wall close bv the end is reduced. however, and part of the wall material is swaged downward slightly into that portion of the tubing which is flared. By thus holding the edge of the tube from any substantial expansion, coupled with the slight upsetting or swaging of the material toward Where the greatest stretch of the tubing will normally occur. it is possible to flare the present available tubing without rupture or weakening of the tube wall.

1 Claim. (Cl. 153--79) Referring now to Figure l, there is shown in separated relation the various parts of a preferred form of flaring means for practicing my invention` These comprise a block or clamping ring I0, a pair of jaw holders I2, I4, a pair of flaring jaws I6, I3, and a flaring plunger 2B.

The block I0 may be secured in a vise but its outer surface is lrnurled so that it can be held in ones hand. It has a tapered axial hole Ia extending through it.

The jaw holders i2, I4 have exterior curved surfaces I2a, Ma tap-ered to t the wall of the hole Illa in the clamping ring lil, and also have opposed flat surfaces IZb and Illb. Each holder has a semi-cyclindrical recess I2C, Mc which terminates in an enlargement i201, Md at the upler end to provide a shoulder I2e, Me. When the holders are together they provide a cylindrical hole between them for the reception of the Haring jaws I-6 and I8.

These jaws have external cylindrical surfaces I 6a, 18a and external shoulders I 5b, Ib to t the hole formed by the holders I2, ifi. A clamping jaw may be held to a holcer by a screw 22, whose threaded portion passes through a shouldered hole in the holder and screws into a tapped hole in the jaw. Each jaw has for most of its length a semi-cylindrical recess |50, Ic. butat its upper end is particularly formed with tapered surfaces ISd, lad which diverge outward et an angle from the axis equal to one-half the degree of flare to be imposed on the tubing- 24. Each outwardly tapered surface ltd Id extends al^ng the axis as far as desired to make the lens-5th of the flare wanted. From the ring of greatest diameter of the outwardly flared surface, the wall is tapered inward sharply, as at ite and le, to terminate in a short cylindrical portion ttf, Isf, a little larger than the outside dimension of the unilared tube.

The aring plunger 28 has a cylindrical portion 29a substantiallv the same size as the hole in the tubing to be flared. From this portion, to another cylindrical portion 2F5b, is a tapered or flaring surface 20c making an angle with the axis of the plunger equal to the degree of flare to be imposed on the tubing, The diameter of the larger cylindrical portion 2th of the plunger is slightly less than that of the short cylindrical hcle formed by the portions if and I'Sf of the flaring jaws.

In the practice of my improved method the tubing 24 to be flared is placed between the jaws I6 and I8 with its end 24a extending slightly beyond the ends of the jaws as shown in Figure ,2. The jaws are set in the holders I2 and I4 and the latter in the ring I0. The larger ends of the holders are preferably tapped lightly with a hammer to tighten the jaws against the tubing. The plunger 20 is inserted in the tubing with its ared portion 26e resting on the edge 24a of the tube. The latter edge, by the way, need not be cut or finished with any special care but may be the edge left when tubing is cut with a hack saw or pipe cutter.

The plunger is now subjected to hammer blows until the flaring is completed. In Figures 4, 5 and 6 I have attempted to illustrate what I believe occurs as the aring takes place. As the plunger is driven into the tubing the holders I2 and I4 settle very firmly into the ring I0, causing the jaws I6 and I8 to grip more tightly the tubing 24 between them. As the flared surface 20c of the plunger moves downward it applies an increasing fricfional force solely to the inner surface of the tubing between the edge 24a and the uniared surface of the tubing. The axial components of this force act with swaging effect on the tube Wall, gradually thinning it opposite the portions I Bf and l8f of the jaws. Part of the metal displaced by the swaging action may move upward to swell very slightly the edge 24a of the tubing, but for the most part it moves downward and apparently slightly thickens the tubing just below the said portions IBf and If of the jaws.

As the progress of the plunger continues the radial components of the above mentioned frictional force act to displace the wall of the tubing outward into the space around it, formed by the tapered surfaces Id, I8d, I6e and I8e, until when the plunger bottoms (that is, when the lower end of its flared portion is opposite the lower ends of the flared portions of the aring jaws) the wall of the tube is dared outward as desired and as shown and thus produce the finished ilared end 24e f shown in Figure 8f Examination of the 11a-red end discloses no rupture, tear or crack in the tubing. The entire flared portion is intact. If anything, it may be slightly stronger than would be the case if flared in the usual way, because despite the increased circumferential size, the wall thickness of the flared portion is not appreciably thinned but usually measures as thick as the original thickness of the tube wall.

This application is a division of original application Serial No. 509,931, filed November 11, 1943, issued March 9, 1948, as Letters Patent No, 2,437,285, in which in response to a requirement for division the method claims were cancelled, applicant then reserving the right to lile a divisional case pertaining to the method disclosed in the original application.

I claim:

The method of forming a tapering flared portion on tubing which comprises holding an unilared portion of the tubing on one side of the portion to be flared against displacement in the direction of the axis of the tubing and holding the external surface of the tubing on the other side of said portion to be ared against displacement in direction radial to said axis, applying an increasing frictional force solely to the inner surface of the tubing between its end and the unflared surface, the axial components of said force simultaneously displacing in direction along the axis a portion of the wall of the tubing whose external surface is being held against radial displacement, and the radial components of said force displacing the Wall of said tubing at said portion to be flared outward progressingly from the said unfiared portion to form the desired tapering ared portion.

I JAN/IES R. WELSHMAN.

REFERENCES CITED The following references are of record in the le of this patent:

` UNITED STATES PATENTS Number Name Date 410,000 Matheson Aug. 27, 1889 412,389 Isherwood Oct. 8, 1889 606,046 Chillingworth June 21, 1898 1,724,920 Fischer Aug. 20, 1929 1,791,887 Davies Feb. 10, 1931 1,804,815 Schultis May 12, 1931 1,817,854 Sorensen Aug. 4, 1931 1,851,276 Gordon Mar. 29, 1932 1,911,186 Gordon May 30, 1933 2,024,803 Nelson Dec. 17, 1935 2,124,743 McMahon July 26, 1938 2,211,242 McIntosh Aug. 13, 1940 2,437,285 Welshxnan Mar. 9, 1948

Images