US 2493127 A
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Jan, 3, 1950 G. E. FRANCK 294939127 1 TOOL FOR EXPANDING AND SIZING THE ENDS OF METALLIC TUBES Filed July 15, 1944 NVENTOR.
GewjgeEflanci Patented Jan. 3, 1950 UNITED STATES ATENT OFFICE TOOL FOR EXPANDING AND SIZING THE ENDS OF METALLIC TUBES Application July 15, 1944, Serial No. 545,097
my invention relates to hand service tools which are useful in expanding tubing so that a joint may be made between two pieces of tubing of the type adapted to be sealed by means of solder or some similar sealing material.
Among the objects of my invention is to provide a new and improved tube expanding or swaging tool which is capable of both expanding the end of a piece of tubing and sizing the expanded portion with sufficient accuracy over a substantial portion of its length so that when another piece of tubing is inserted into it there will be a firm neat fit between the two.
Another object of my invention is to produce a swaging tool for expanding tubing which utilizes only a relative minimum amount of pressure in order to force the tube intoits expanded condition.
Still another object is to provide a new and improved swaging tool which is so constructed that the force of friction on the part which performs the actual work of expanding is reduced substantially to a minimum and providing on the same tool a sizing portion which will bring the expanded part of the tube to size without the expenditure of force necessary to overcome a large frictional resistance.
A further object of my invention is to provide a service tool for producing an expanded end upon tubing by means of a swaging operation wherein the expanded end is given a uniform size over a considerable length so that when a second length of tube is inserted the parts will not wobble excessively one with respect to the other and will thereby make possible the production of a sweated joint which is strong and serviceable.
Still a further object is to produce a small and convenient hand service tool which can be used to expand the ends of tubing with relative ease and which is so constructed that it can be used with equal ease and adaptability for making expanded joints on several different sizes of tubing.
With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my device whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawings, in which:
Figure 1 is an end view partly in section showing a hand service tool incorporating the novel features of my device.
Figure 2 is a top view partly in section taken on the line 22 of Figure 1.
Figure 3 is an enlarged sectional view of the expanding member of my device shown in position at the end of a tube which is to be expanded and taken on the line 33 of Fig. 2.
Figure 4 is a longitudinal elevation shown with the expanding member in a position driven partly into the end of a tube, with the tube shown in longitudinal section.
Figure 5 is a view showing the expanding member in elevation driven all of the way into a tube shown in longitudinal section.
Figure 6 shows a longitudinal section of the expanded end of the tube.
Figure 7 shows a longitudinal section of a joint made by use of the expanded tube.
Figure 8 is an elevational view of the joint shown in Figure 7.
In order to make a tight sweated joint for thin walled tubing such as copper tubing it is highly desirable to have the expanded end of the tubing made to such a size that it will snugly engage a length of tubing inserted into it over a considerable portion of the joint. The more snugly the fit is made the less freely the parts will wobble one with respect to the other and with wobbling reduced to substantially a minimum it is much easier for a mechanic to hold the parts in proper relationship until the sweated joint is completed and the solder hardened in place.
In swaging tools which have been developed in the past it has been common practice to make the outside diameter of the expanding portion of the die the same diameter which the inside diameter of the expanded portion is expected to have. This means making the diameter of the expanding part of the die the same as that of the outside of the tubing which is used.
In actual practice it has been found that as a tube stretches outwardly under the force of expansion it has a tendency and does actually stretch to such an extent that the diameter of the expanded portion immediately adjacent the expanding part of the die is actually greater than the diameter of the die. This may result by reason of the particular flow characteristics of a ductile metal which is being shaped. However, even though the initial expansion may be greater than desired, as expansion continues and the expanding part penetrates further into the end of the tube the edge of the tube which has been expanded turns inwardly again until it attains a diameter about equal to the diameter of the expandin part of the die. This return to size occurs on the free end of the tubing and to a lesser extent on the remaining part and the expanded portion instead of having a cylindrical shape fitting snugly around the tube has a close fit only at the very end. As a result the remaining length of the expanded portion of the tubing is slightly greater in diameter than the outside diameter of the tubing at all points between the outside end and the part immediately adjacent the expanding part of the die. The diameter is usually greatest immediately beyond the expanding part of the die so that the enlarged end of the tube is somewhat wedge-shaped.
When the tube is expanded in the fashion just described there is a snug fit only at the very end of the expanded portion and the remaining parts of the expanded portion, being slightly oversized, will provide a relatively loose fit for the tubing inserted therein thereby permitting the parts to wobble one with respect to the other making it difiicult to properly freeze a sweated joint. This invention is directed to a means of producing a snugly fitting expanded end on a tube which has a cylindrical shape, rather than being wedgeshaped in section, for a substantial portion of its length and which is so sized that the cylindrical portion at all points will snugly engage the outside of a tube of the same nominal size.
In the drawings there is shown a pair of tube clamping blocks l and I2 here having a length long enough to be considered as bars. The bars are each provided with semicircular tube holding recesses 14 and I6. These bars may be held together at the ends in clamped position upon a length of tubing Is by means of bolts and 22 swivelly mounted at the ends of one of the bars and held in position in a hole or slot in the other bar by wing nuts 24 in a well-known manner. As shown in Figure 2 the bars are provided with additional recesses 28, 29, and 3| to accommodate tubes of various sizes.
A yoke 32 is provided having legs 34 and 3B which extend to a position adjacent the clamping bars and the legs may be provided with foot elements 38 and 40 adapted to engage the underside of the clamping bars.
At the end of the yoke opposite from the foot elements there is provided a threaded aperture 42 and a threaded shaft M mounted in the aperture. The shaft has a head 36 and a handle 48 extending crosswise and adapted to rotate the shaft to move it down or up.
The actual swaging or expanding is performed by means of a die so which has a threaded upper end 52 designed to engage a threaded collar 54. The shaft 44 at its lower end is provided with an annular recess 56 designed to receive a split ring 58 thereby providing a means for swivelly securing the threaded collar upon the lower end of the shaft.
The die is provided with an axially extending recess 50 having a sloping bottom '62 and the shaft is provided with a substantially cylindrical thrust element 64 fitting loosely in the recess and having a sloping end 65 designed to fit into the bottom of the recess in order to take up the thrust between the die and shaft. At its lower end as viewed in Figures 1, 3, 4 and 5, the die is provided with a pilot portion 61 having a diameter slightly less than the minimum inside diameter of the tubing l8 which is to be expanded. By keeping the pilot slightly smaller the die is free to center itself in position in the end of the tube. Likewise by reason of a loose fit between the shaft and the recess in the die a straight line thrust can 'be given the die even though the shaft may not be in precise alignment.
Adjacent the .pilot portion 61 is an annular rounded bead 68 the outermost circumference 69 of which is slightly less than the outside diameter of the tubing although the difference may be a matter of only a very small fraction of an inch. This bead, moreover, as seen in the drawings, has a small radius of curvature, preferably less than five-thirty-seconds of an inch. A bead of small radius is employed for it makes for minimum area of contact with the tubing and thus for minimum frictional force resisting movement of the die into the tubing. It has been found that the frictional force can and does play a tremendous part in the relative difficulty or ease with which a swaging tool can be forced into a .piece of tubing. A bead of small radius is employed for the further reason that it forms a distinct shoulder in the tubing serving as a stop limiting the extent that a piece of tubing may be inserted into the expanded end.
Adjacent the bead on the side opposite the pilot portion is an annular recess 10, the width of which is not critical but which should be about the proportion shown in Figures 3, 4, and 5.
The die is further provided with a relatively wide cylindrical sizing portion 12 immediately adjacent the recess which is substantially the size of the outside diameter of the tubing and which will give an already expanded end ll of a piece of tubing its proper size. A shoulder 14 prevents the die from being screwed too far into the threaded collar.
In operation a length of tube of the proper size is first clamped between the clamping bars as shown in Figures 1 and 2 with a substantial part of the tube protruding above the bars. With the tube in place the yoke 36 is then slid over the bars until the die is centered above the open end of the tube. The threaded shaft 4 3 is screwed downwardly until the pilot portion 6! enters the tube as shown in Figure 3.
Then as more pressure is exerted upon the handle the die is thrust into the end of the tube. When this occurs the annular rounded bead gradually works the wall of the tubing outwardly into its expanded position as shown in Figure 4. Since only a line contact is present between the rounded perimeter of the bead and the tubing only a relatively light force need be exerted to drive the die through an expanding operation. The tube adjacent the rounded bead may expand slightly beyond the outside diameter of the bead and there will be no restriction to its movement after it expands beyond the bead because the end will then be adjacent the recess 10. The expanded portion of the tubing tends to take a slightly bowed or wedge-shaped form with the end 16 initially spread, and later drawn inwardly to the diameter of the annular head which gives it its expanded size. The cylindrical sizing portion then enters the end of the expanded tube and irons out and resizes the expanded end of the tube thereby bringing the expanded 'end of the tube to its proper size over a 'substantial portion of its length.
After the expanding operation has been completed the tube end H will have the shape shown in Figured. This means that the upper end 16 will have the same inside diameter as the outside diameter of the tube and that a considerable portion of the length of the expanded part will have precisely the same diameter given to it by the sizing portion 12. This is a diameter whichsnugly encompasses the outside wall of a tube 18 which is inserted into it. The tube can be pressed into the expanded end until it abuts a shoulder 80 in the expanded portion where the tube changes size. When the tube length is thus inserted it is supported over a substantial part of its area of contact and at the end where it abuts against the expanded portion.
With the parts 80 and 18 thus snugly engaging each other it is possible for a mechanic to flow solder into the space between the tube parts without having them wobble out of place while the solder is setting and under those circumstances the solder will freeze the parts in proper alignment.
There has thus been provided a hand service tool which by utilizing a rounded bead-shaped expansion element provides a tool which can be quickly and easily driven into the end of a piece of tubing with the expenditure of a relatively minimum amount of pressure and provides further a tool which will properly size the expanded end. The effectiveness of the tool thus provided is further enhanced by the provision of what is in effect a thrust bearing between the shaft and the die thereby permitting the die to remain rotatably fixed while the shaft is rotated to force it through a swaging operation.
Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure, or use of mechanical equivalents, which may be reasonably included within their scope.
I claim as my invention:
1. A die for uniformly expanding and sizing an end of a piece of tubing to a size sufficient to permit insertion of an end of tubing of the same nominal tube size having at the end first to be inserted into the tubing a cylindrical pilot portion of a diameter just smaller than the inside diameter of the tubing, an annular rounded bead adjacent the pilot portion with a diameter just slightly less than the outside diameter of the tubing, an annular recessed portion adjacent the bead, and a sizing portion cylindrical in form and of a diameter substantially equal to the outside diameter of the tubing.
2. A die for uniformly expanding and sizing an end of a piece of tubing toa size sufficient to permit insertion of an end of tubing of the same nominal tube size having at the end first to be inserted into the tubing a pilot portion of a diameter smaller than the inside diameter of the tubing, an annular sharply rounded bead adjacent the pilot portion forming a distinct juncture therewith and having a diameter just slightly less than the outside diameter of the tubing, an annular recessed portion adjacent the bead, and a sizing portion of substantial axial dimension adjacent the recessed portion, said sizing portion being cylindrical with a diameter substantially equal to the outside diameter of the tubing.
3. A die for uniformly expanding and sizing an end of a piece of metallic tubing to a size sufficient to permit insertion of an end of tubing of the same nominal tube size having at the end first to be inserted into the tubing a cylindrical pilot portion of a diameter just smaller than the inside diameter of the tubing, an annular bead adjacent the pilot portion, said bead having a radius of curvature not exceeding five-thirtyseconds of an inch and a diameter just slightly less than the outside diameter of the tubing, an annular recessed portion adjacent the bead, and a sizing portion of substantial axial dimension adjacent the recessed portion, said sizing portion being cylindrical with a diameter substantially equal to the outside diameter of the tubing.
GEORGE E. FRANCK.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 10,488 White Jan. 31, 1854 123,584 Shriver Feb. 13, 1872 632,502 Monnier Sept. 5, 1899 682,250 Glauber Sept. 10, 1901 1,646,384 Bergstrom Oct. 25, 1927 1,647,447 I-Iartnett Nov. 1, 1927 1,850,178 Mc Chesney Mar. 22, 1932 1,886,807 Heidoff NOV. 8, 1932 1,998,653 Briegel Apr. 23, 1935 2,07 ,359 Dobrick Mar. 2, 1937 2,132,947 Gagne Oct. 11, 1938 2,155,416 Geyer Apr. 25, 1939 2,278,982 Kellems Apr. 7, 1942 2,298,379 Hofiman Oct. 13, 1942 2,314,221 Kellems Mar. 16, 1943 2,346,376 Heavener Apr. 11, 1944 FOREIGN PATENTS Number Country Date 29,634 Switzerland Oct. 15, 1910