US499979A - field - Google Patents

Description

(No Model.) 4 Sheets-Sheet 1.- J. A. FIELD. SCREW CUTTING MACHINE.

N0. 499,979. Patented June 20, 1893.

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4 Sheets-Sheet 2. A. FIELD. CUTTING MACHINE.

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Patented June 20, 1893.

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(No Model.) 4 Sheets-Sheet 3.

J. A FIELD. SCREW CUTTING MACHINE.

Patented June 20, 1893.

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(No Model.) 4 Sheets-Sheet 4 J. A. FIELD. SCREW CUTTING MACHINE.

No. 499,979. Patented June 2-0, 1893.

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UNITED STATES PATENT OFFICE.

JESSE A. FIELD, OF BUFFALO, NEW YORK.

SCREW-CUTTING MACHINE.

SPECIFICATION forming part of Letters Patent No. 499,979, dated June 20, 1893.

Application filed August 29, 1892.

T0 at whom it may concerns Be it known that I, JESSE A. FIELD, a citizen of the United States, residing in Buffalo, in the county of Erie and State of New York, have invented certain new and usefullmprovements in Screw Cutting and Tapping Machines, of which the following is a specification. U

My invention relates to certain improvements in machines for cutting screw threads and will be fully and clearly hereinafter described and claimed, reference being had to the accompanying drawings, in which Figure 1 is a side elevation of the machine, showing the mechanism for operating the screw cutting head. Fig. 2 is a plan view of the machine showing a similar view of the working mechanism. Fig. 3 is a detached side elevation of the cam arm for moving the screw cutters back and forth. Fig. 4 is an enlarged front elevation of the cutter head. Fig. 5 is a longitudinal section through the cutter head on or about line 0 c, Fig. 4, looking in the direction of the arrow W, showing the screw cutters in position for cutting an interior screw thread. Fig. 6 is a longitudinal section, in or about line a c, Fig. 4 through the cutter head, the screw cutters being omitted so as to show the construction of the head more clearly. Fig. 7 is a similar longitudinal section, also in or about line 0 c, Fig. 4, showing the cuttors in position for releasing themselves from the screw thread after'being cut. Fig. 8 is a side elevation of the cam wheel (looking at it from the back side of the machine) showing that portion of the cam which causes the head to move backward while the continuously rotating screw cutters remain stationary in their longitudinal positions and while thus stationary are gradually moving away from the screw thread which has been cut so that they can be easily drawn out while still rotating without interfering with said screw thread, showing also that portion of the cam for reversing the movement or moving the cutter-head and screw cutters back again up to the work to be cut. Fig. 9 represents also a side elevation of the cam wheel showing that portion of the cam which causes the screw cutters and cutter-head to move at the same speed at which the screw thread is being out. Fig. 10, is a longitudinally nearly Serial No. 444,342. (No model.)

central section in or about line a c, Fig. 4, showing a modification of the cutter-head adapting it for cutting an outsidescrew thread.

- Fig. 11, is a reduced rear elevation of the sliding collar to which the screw cutters are secured, looking in the direction of the arrow, F, Fig. 10.

- The supporting frame of the machine is shown in Figs. 1 and 2.

The cutter head shaft, 1, is mounted in boxes 22, in the vertical frame pieces 3 and 4. These frame pieces are rigidly secured to a base piece, 5. The rear end of the cutterhead shaft, 1, which rotates continuously and also has a longitudinal movement while in operation is provided with a small pinion, 6, made long enough to allow for the longitudinal movement of the cutter head shaft. Back of this pinion, 6, is represented a crank and handle 7 and 7, by which it may be operated when adapted for small work. For larger machines, a pulley would be substituted for the crank and be connected with a steam engine or other suitable source of power.

Mounted on vertical supporting pieces 8 and 8, in boxes 9 and 9", see Figs. 1 and 2, so as to rotate easily therein, is a cam shaft,

10, (shown in Fig. 2.) On this shaft, 10, is

mounted and rigidly secured'a cam wheel, 11, and at the rear end of the shaft, 10, is rigidly secured by a key or in any well known way, a spur gear wheel, 12, adapted to gear in with the pinion, 6, on the cutter shaft 1. The cam wheel, 11 .is connected bya friction roller, 13, pivoted by a pin to the collar, 14, which collar is mounted on the cutter head shaft so that the shaft can turn easily within it, but is prevented from moving longitudinally by means of the collars, 15-15. These collars are rigidly secured to the screw cutter head shaft 1 by means of the screws 16-17. The friction roller 13, fits and turns easily in the groove cam, 18, in the cam wheel, 11. The shape and operation of this cam will be described farther on. v

The collar, 14, carrying the friction roller, 13, while it is adapted to move longitudinally with the screw cutter head shaft, 1', does not rotate. It is kept from turning by a down wardly projecting pin, 19, shown in Fig. 1. This pin, 19, projects down into a longitudinal groove in the top of a stationary standtop of the standard, 20.

Near the forward end of the cam-shaft, 10, is a loose sleeve, 21, (shown in Fig. 2,) and it is kept stationary so that the shaft 10 turns within it, by means of. a vertical bar, 22, (shown in Fig. 1,) the upper end of which is secured to the under side of the sleeve and the lower end is secured to the base, 5. The forward portion of the sleeve, 21, is provided with a small inclined projection, 23, the inclined face of which inclines upward from the rear toward the front or in the direction of the arrow V. This inclined catch or proj ection always remains stationary.

At the front end of the cam shaft, .10, is another sleeve, 24, (see Fig. 2) secured rigidly thereto by a set screw, 25, so that it turns with the shaft. To this sleeve, 24, is rigidly secured an angular bar, 26.

On the cutter-head shaft, 1, is a collar, 27, rigidly secured thereto by set screws, 28, and

between this collar, 27, and the cutter headis a-=sleeve, 29, (see Fig. 10, where this sleeve-is more plainly shown) mounted loosely on the shaft, 1, so that the shaft can rotate easily within itand it can also be moved longitudinally backand forth on the shaft. This sleeve, 29,

is provided with an enlarged portion or flange, 30, at one end, and a collar, 31, secured there-- to by screws, 32, at the opposite end.

Between the flange, 30, and the collar, 31, is

a loose sleeve or collar, 33, and over the sleeve or collar, 33, the yoke or circular portion, 34, of' an arm, 35, is passed and securedto the sleeve 33, by the set screws, 36. One end of the arm, 35, is pivoted to a vertical-support ing standard, 37, and the opposite end is. secured to one end of a spring, 38, having its opposite end secured to a supporting standard 39, (shown in Fig. 2.)

The arm, 35, while the machine is in operation moves on its pivot, 40, back and forth substantially as shown by the dotted lines 41 and 42, in Fig. 2.

From the above description it will be seen that by turning the crank arm 7 and 7, so as to turn the cam, 18,-in the direction of the arrow, :10, shown on said cam in Fig. 2, the shaft, 1, will receive a longitudinal reciprocating movement back and forth and thereby give the arm, 35, by means of the friction roller 13 and its connection with the cam 18, a back and forth swinging movement as hereinbefore mentioned. The construction of the cam for giving these movements will be better understood by reference to Figs. 8 and 9. The views of Figs. 8 and 9, being taken from the rear side, their direction of rotation would.

beindicated by the arrow 2' Fig. 8.

In Fig. 9, 18 represents that portionof the camthat moves the screw cutters forward with the exact speed required to cut the screw thread it is intended for.

That portion of the cam marked, 43, is that part of the groove that can :es the cutter head .to move backward while the screw cutters are stationaryin their longitudinal position and at the same time are moved toward each other or are drawn outfrom the screw thread that has been cut, so thatthey can be instantly withdrawn therefrom without reversing or stopping their rotary movement, or in other words, the severalparts are moved from the position shown in Fig.5 to the position shown in Fig. 7.

That portion of the cam marked43,is that part which partly reverses this last movement so as to bring the cutter head and its screw cutters up to thework, preparatory to cutting another screw thread.. 7

The cutter head consists ofan outer shell 44 and an inner portion, 45, 45, see Fig. 6, where the cutter head is shown without the cutters; the part 45* is a reduced portion againstwhich the cutters rest as'they enter the hole to be cut. The shell, 44, is slipped over the tapering portion,45, and then rigidly secured thereto by screws, 46, but any wellknown means for fastening it may be used.

The part, 45, forms-a portion of .the shaft, 1,

but it may be secured to it in any wellknown ;way if desired. In this-headwhen thus put together are four openings, .47, (but there may bemore or less than thenumber shown) in. which the screw cutters, 48, havinga series of screw cutting teeth 49, are placed so as to slide easily back and forth but at the same time areclosely fitted, see Figs. 4-5 and 7.

Above each cutter, 48, is another bar, 50, having a corresponding series of teeth adapted to fit exactly'in the teeth, 49, and on the inner side of each screw cutter is a wedge shaped bar, 51, having its smaller end turned upward toward the bar, 49, and provided with a projecting piece or tooth, 52. This tooth 52,

fits within a notch inthe bar, 50, so thatwhen the bar, 50,-is moved back and forthall the bars 4850 and 51 move together.

hole, 53, to which the forked bars 54, are pivoted by pins, 55, seeFigs..12 and 10, par- I I5 At the end'of each bar, 50, is an elongated ticularly Fig.10. These forked bars are each 1 provided with a screw portion, 56, which passes through a hole in the flange, 30, of the sleeve, 29, (see Fig. 10, where this construction is shown) and each' is secured firmly in place by a nut, 57. These nuts are put in the openings, 58, in the sleeve; 29, shown in Fig. 10, and by dotted lines in the reduced rear elevation of the sliding collar, 29, which as hereinbefore mentioned, receives a longitudinal reciprocating movement on the shaft, 1, by

means of the cam-way, .18--43 and 43, and the friction roller, 13, pivoted to the collar, 33, so as to operate in said cam-way.

To keep the screw cutters 48 close to their seats in the heads, 45, I employ a series of l screws 59. These screws are made hollow so asto each receive a spring, 60, see Figs. 5 and 7.

In Fig. 10 I have shown a slight modification of the cutter head by which it is adapted for cutting an outside screw thread. It will be noticed that the position of the cutters and their several parts are reversed, the wedges, 51, being outside the screw cutters, 48, inside of the wedges, 51, with their screw cutting teeth inside instead of being outside as shown in the other figures and correspondingly toothed bar 50, is inside of all. The construction and operation of this cutter head are substantially the same as those described in Figs. 125 and 7, except that the positions of the several parts are reversed andit cuts an outside screw thread instead of an inside screw thread.

The operation of the invention is as follows: The shaft, 1, is turned to the right by means of the crank arm 7 and 7, (or other suitable means) so as to turn the camshaft, 10, in the direction of the arrow, m, and the cam is at or about the point, 61, shown in Fig. 8, so that the first movement will be the passage of the portion, 43*, of the cam which will bring the shaft, 1, and the cutters forward up to the work, or screw to be cut. The portion, 18, of the cam groove now passes by the friction roller and through it, as hereinbefore mentioned, and causes the screw cutters to advance as fast as the screw thread is cut; during this movement (referring now to Fig. 2) the arm, 35,-is being moved from the point indicated by the dotted line, 42, to or about the point indicated by the'dotted line 41; at this point the arm, 35, drops down in front of the inclined catch, 23, and. is held there by said catch until the cam shaft, 10, has turned far enough to bring the angle arm, 26, under said arm, 35, and lift it off. Just before the arm, 35, is lifted off from the catch, 23, the end of the cam portion 18 has been reached and the part, 43, has got around to the friction roller and as it passes it moves the friction roller and shaft backward while the cutters are held stationary in their longitudinal position by the arm, 35, being held by the catch, 23. This operation it will be readily seen-will cause the cutters to contract or move toward each other (and assume the position shown in Fig..7,) so that they can be drawn longitudinally back out of the screw which has been out, without stopping their forward rotary movement as hereinbefore described.

The movement of the cam shaft, 10, is so timed that the arm, 35, is released from the catch at this moment so that the spring, 38, instantly draws it back until stopped by the shoulder, 64, on the box, 9; this action draws the cutters into the proper position to start again, or in the position shown in Fig. 5.

From the above construction it will be seen that the screw cutters are removable and that when a portion becomes worn or dull they can be taken out, and the dull portion broken off,

and then put back. In this way a set of the screw cutters can be made to last a long time or until nearly the whole is used up, after which they can be easily and quickly re placed by new ones.

I claim as my invention 1. In a screw cutting and tapping machine, the combination with a cutterhead shaft mounted in boxes so as to be capable of a rotary and longitudinal movement of a cam mounted on a cam-shaft connected by a gear wheel and pinion with the cutter-head shaft and a friction wheel connecting said cam with a non rotating collar on the cutter head shaft, for giving said cutter-head shaft a movement up to the work, then a movement forward while the screw thread is being cut, and then a movement to draw the cutter head back while the cutters are held stationary in their longitudinal position by an arm pivoted to a stationary support, and to a collar mounted on a sleeve which operates the cutters, and a catch on a stationary sleeve mounted on the cam shaft for holding said arm stationary at the limit of its forward movement as above specified, while at the same time the cutters are being drawn away from the screw that has been cut, a means substantially as above described for releasing the pivoted arm and a spring for bringing said arm and the cutters back to their normal position, substantially as described.

2. In a screw cutting and tapping machine, the combination with a shaft carrying the cuttor-head and mounted in boxes so as to have both a longitudinal and a rotary movement, of a cam shaft mounted in boxes, and provided with aspur gear wheel engaging with a pinion on the cutterhead shaft,a cam wheel rigidly mounted on said cam shaft having a grooved cam way and connected by a friction roller with a collar mounted on a sleeve between fianges, a means substantially as above described for preventing said sleeve from turning, the cam being adapted to give a movement, first, to bring the cutter-head and cutters up to the work, second, to move the cutter head and cutters forward with the proper speed for cutting the screw, third, to bring the cutter-head back to the starting point, substantially as described.

3. In a screw cutting and tapping machine, the combination with a cutter head shaft mounted in suitable boxes so as to have both a longitudinal and a rotary movement, of an arm, 35, pivoted to a stationary support on the machine and to a collar mounted between flanges on a sleeve mounted on the cutterhead shaft, acam shaft connected by gearing with the cutter-head shaft carrying a loose sleeve mounted near the forward end of the shaft and kept stationary by a bar connected with the machine so that the shaft turns within it, a holding catch on said stationary sleeve for holding the arm, 35, when at the limit of its forward movement, an angular arm at the forward end of the cam-shaft for disengaging the arm, 35, and a spring for brin gin gsaid arm .back to its normal position substantially as and for the purposes described.

4. In a screw cutting and tapping machine a cutter head consisting of a tapering portion having a series of grooves to receive the screw cutters, an equal number of wedge shaped bars adapted to fit in said grooves, a toothed screw cutting bar mounted above each of said wedges, a correspondingly toothed bar mounted with the teeth in contact on each of the cutter bars, and rexnovably connected with the wedge shaped bars by a projecting tooth on the wedgeand a corresponding notch on the toothed bar, a means for connecting said bars with the mechanism for operating them, and an outside shell adapted to fit the tapering portion and provided with springs for keeping the cutters and their several parts in 1 position, and a means for rigidly securing said described;

5. In a screw cutting and tapping machine,

each of said screw cutting bars, and a bar having a series of corresponding teeth in contact with the teeth ontheopposite sides of each of the screw cutting bars and a means for connecting the upper and lower bars removably together substantially as described.

JESSE A. FIELD.

Witnesses:

JAMES SANGSTER, ARTHUR J. SANGSTER;

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