US506157A - Method of and machine for bending tubes - Google Patents

Description

(No Model.)

` YMETHODAOBAND MAGHINBFOR BBNDING TUBES. No. 506,157. y I f Patented 001;.. s, 189s.)

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UNITED) SrmussY PATENT OFFicE..

ROBERT CLARKE, OF GRAVESEND, NEW YORK.

METHOD OF AND MACHINE FVOR BENDING TUBES.

SPECIFICATION forming part of Letters Patent No. 506,157, dated October 3, 1893.

Application filed March l, 1893. Serial No. 464.242. (No model.)

To all whom it may concern: l

Be it known that I, ROBERT CLARKE, residing in Sheepshead Bay, (P. O., Gravesend,) Kings county, New York, have invented certain new and useful Improvements in Methods of and Machines for Bending Tubes, of which the following is a specification.

My invention relates to methods of and apparatus for making bent tubes of different metals, as for instance, such tubes as are used for hand rails, boiler tubes, traps, &c., and my invention consists in bending said tubes by forcing them into suitably formed channels in molds, while at the same time forcing through the tubes and at a greater rate of speed, a series ofy hard metal spheres, as fully set forth hereinafter and as illustrated in the accompanying drawings, in which- Figure l is a plan view illustrating the apparatus employed in carrying out my invention; Fig. 2, a sectional plan of the said apparatus, showing also the forcing means. Fig. 3 is a section ou the line 8 3, Fig. 2. Fig. 4 is a plan showing a dierent form of die. Fig. 5 is an elevation also showing a different form of die; Fig. 6, a sectional elevation, showing a die as used for curving spiral tubes.

The operative partsl of the bending apparatus are mounted upon a base, A, of any suitable construction, said operative parts consisting essentially of die sections having between them an opening or channel corresponding to the form to be impartedv to a tube. According to the purpose to which the bent tube is to be applied, this form may correspond to a part of a circle lying all in one plane, or it may conform to a spiral as is requisite in bending tubes to a spiral form for boilers, zc., or the curve instead of being circular may correspond to part of an ellipse or oval as circumstances require.

It will be evident that the form and construction and arrangement of the die sections will depend upon the form to be imparted to the tube, but there is generally an inner section, B, and an outer section C, and I prefer to make the inner section in the form of a wheel having an annular groove at the periphery and the section C, whatever its form, will also have a groove so as to form with the groove in the section B, a channel of the proper shape.

As shown in Figs. l, 2 and 3, the section C is a block recessed to receive about one-half the diameter of the wheel section B and conforming tothe periphery of the latter, and

having in the part opposite the said periphmerely pushing the said tube endwise into said channel would not result in forming a perfect bend, that is', 4the tube would be creased and wrinkled, if not llattened in the eort to push it through the curved channel.

I therefore provide for means for maintaining the cylindrical form of the tube notwithstanding the pressure and the variations of pressure which vmust beput upon it in forcing it through the channel, the same consisting in inserting in the tube a number of spheres e, preferably of hardened steel, and

which accompany the tube in its movements through the channel and which are withd rawn after the tube has been properly bent. I have discovered that if the spheres are pushed with the tube at the same speed at which the latter moves, the bending is not perfectly accomplished, but on the contrary, lthe tube is wrinkled and distorted so that it is difficult to remove the spheres after the bending has been eected. I therefore provide means whereby the spheresare caused to travel through the tube at a greater speed than that at which the tube is introduced -into the channel, so that the spheres have a sort of a rolling action tending to iiatten and draw out the metal and preserve the absolute cylindrical form of the interior of the tube, notwithstanding the variations in the strain at diiferent parts of the tube. While different means may be employed for imparting this difference in motion of travel to the tube and to the internal spherical balls or mandrels, I have found that an effect-ive means of operation consists in forcing the tube into its channel by means of a hollow plunger D, moving l at the proper rate of speed and in forcing the series of balls ICO through the tube by means of a solid cylindrical plunger or rod E traveling at a higher speed than that of the plunger D. The sections B, C of the die are each separable from the base A, the wheel or disk B being held by a detachable bolt or pin 8 and the section C by bolts or pins 9. Various means for inlparting this dierential movement to the two parts will be evident to any one skilled in the art. As shown in Fig. 2, the said means consists of ahand wheel I, the hub D of which is hollow and constitutes the hollow plunger D upon which the ends ot' the tube X bear, a hollow tubular extension 4 of the plunger D having threads fitting a threaded opening in a standard 5, the threads being at such a pitch that the revolution of the wheel I will impart the requisite degree of traveling movementto the hub or plunger D. The plunger D and the tubular extension 4 are also threaded with a. pitch very much greater than that of the exing curved metal tubes, of a die consisting of two sections having a curved channel between tension 4 and adapted to the threads upon the plunger E, so that when the wheel is turned i-t will impart to the plunger E a quick, forward, traveling movement, and the wheel itself will also travel forward in its bearing 5 but at a much less rate of speed. The difference between the speed of one plunger and the other may be any difference which is found most eectlve. As a general thing, I t

` a tube bending machine, and with a series of .spheres adapted to be arranged Within the find that a difference of five to one will, in many cases, be sufficient; but it may be greater or less as circumstances demand. The construction illustrated in Figs. 1, 2 and 3 will suffice where the tube is to be bent to anything less than a half circle, or where it is to be bent to a full circle, the section C should extend completely around the section B of the die, as illustrated in Fig; 4; and where the tube is to be bent to a spiral form, the section B is set at an angle to part of the section O, as illustrated in Fig. 6. It is not necessary that the section C should be a solid block; it may consist of a series of grooved rollers, 7, as illustrated in Fig. 5, and the section B itself may consist of aV series of grooved rollers as illustrated in dotted lines, Fig. 2. Where the section B consists of a wheel, it may be divided longitudinally into two sections upon the plane illustrated by dotted lines y, Fig. 5, so that if more pressure comes l upon one section or the other, such section may move more readily or at a greater speed than the other, and when the outer section consists of grooved rolls 7, they may likewise be divided centrally upon the same plane.

Without limiting myself to the precise construction and arrangement of parts shown, I claim- 1. The within described improvement in the manufacture of bentv metal tubes, the same consisting in pushing the tube under endwise pressure into a curved channel and at the same time pnshingthrough the tube at a greater speed a series of spheres, substantially as set forth.

`2. The combination in a machine for makthem for the reception of the tube to be bent, a series of spheres arranged within the tube to be bent, and means for pushing the tube through the channel at one speed and the spheres through the tube at a greater speed,

. substantially as set forth.

3. The combination with the dies B, C, of

ROBERT CLARKE.

Vitnesses:

C. MOORHEAD, JOSEPH H. SAUNDERS.

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