US255409A - Gear-cutting machine - Google Patents

Description

(No Model.) 7 5 Shets-Sheet 1. A. H; BRAINARD.

GEAR GUTTINGMAQHINE. No. 255,409. Patented .Mar. 28, 1882.

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GEAR CUTTING MACHINE. No. 255,409. Patented Mar. 28,1882

(No Model.) 1 5 SheetQ-Sheet a.

A. BRAINARD.

GEAR CUTTING MACHINE. No. 255,409. g Patented Mar. 28,1882

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GEAR GUTTING MACHINE.

@ No. 255,409. Patented Mar. 28,1882

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(No Mod'el.) j I 5Sheets-Sheet 5.

A. H. BRAIN-ARD.

GE-AR CUTTING MAGHINE.

No. 255,409. Patented Mar. 28,1882. v

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2o partial front elevation of the machine.

' UNITED STATES PAT NT O FIGE.

,AMOS H. BRAINARD, OF HYDE PARK, MASSACHUSETTS.

GEAR-CUTTING MACHINE.

SPECIFICATION forming part of Letters Iatent No. 255,409, dated March '28, 18 2.

' Application filed September 19, 1881. (No model) To all whom it may concern Be it known that I, AMos H. BRAINARD,-t citizen of the United States, residing at Hyde Park, in the county of Norfolk and State of Massachusetts, have invented certain new and useful Improvements in Gear-Cutting Machines; and I do hereby declare that the same are fully described in the following specification andillustrated in the accompanyin g drawto ings.

i able bracket. Fig. 3 represents a detail side view' ofthe dividing mechanism for turning the worm-wheel and the gear to be cut. Fig. 4 represents a side elevation of the adjustable table for the cutter-shaft. Fig. 5 represents a Fig. 6 represents a detail view of the centering de- ,vice for arranging the cutter centrally with the axis of the wheel to be cut. Fig. 7 represents a cross-section of the worm and wormwheel on thelineXY, shown in Fig. 2. Fig. 8

represents an enlarged central longitudinal section of the cutter-arborand cutter; and Fig.

9 represents an enlarged cross-section on the line U V, shown in Fig. 5, showing theiudicao tor for setting the cutter to the exact depth of means of a worm and worm-wheel, as distinguished from thosein which the dividing mechanism is either adial drilled with the necessary,

number of holes or a spur and ratchet-wheels.

In this machine are several special devices to attain and maintain unusual accuracy,- as willherein be more fully described.

a is the standard or frame of the machine,

having in its upper end a bearing, b, for the shaft 0, to the rear end of which is secured the worm-wheel e, and to theforward end of which is secured the wheel d that is to be cut.

' f is the worm, and j" is the worm wheel shaft by means of which the worm-wheel e is operated. The shaftf' is located in bearingsff on the vertically-adjustable bracket F, the latter being adjustable up and down on the rear of the standard a by means of the set-screw a passing through the screw-threaded ear or lug a, cast on the standard a, and by these means the worm f can be adjusted in its relation to the worm-wheel etc the utmost nicety, and after being so adjusted the bracket F is firmly secured to the standard a by means of the setscrews gy passing through slot-holes g g in the bracket F and screwed in to the standard a. The purpose or object to be attained by the above-named combination of worm-wheel e,

worm-carrying bracket F, set-screw a, and

insuring a smoother cut for the teeth of gearwheel on the other end of the arbor than is possible in ordinary gear-cutting machines. The bracket F is also provided with bearings ff for the dividing-shaftf the change-gears connecting the shafts f and f" to convey motion from the latter to the former.

The worm-wheel c is made in two parts.

namely, the main .body c and the annular rim c, the latter being made half as wide as the whole worm-wheel c, and fitted into an annular recess on the side of the worm-wheel c, and secured thereto by means of set-screws c c, as shown in Figs. 2,and -7. The thread in the Worm-wheel for the worm fis made onehalfin the body of the wheel and one-halfin the annular rim 0, and in thismanner 1 obtain a divided worm-wheelinmore easy, simple,and durable manner as comparedwiththe usual way of making worm-wheels of two equally large disks or plates, which is objectionable in wheels of large size on account of the difficulty of getting a perfect hearing all over such large surfaces, and it would require very thick and heavy disks or plates to finish well. The same result is obtained in a more simple way in my arrangement and construction as above described.

I do not claim as my invention aworm-wheel made in two parts, as such have heretofore been made; but they have in fact been two wheels divided through their whole diameter. By making the worm whecl as hcreinabove described in accordance with my inventionthat is, with a main body and a separate rim the labor of making is veiy much simplified, and the strength and stability of the wheel increased without increasing its weight, a very important consideration in making wheels of large diameters.

When cutting bevel-gears with a rotary cutter it is usually necessary to make three cuts,

the first directly to the center in a straight line, then one on each side of the center line to get the necessary difference in width of cut on the outer and inner ends of the teeth. In common practice this is altogether a matter of experiment with each bevel-gear, depending entirely on the eye and experience of the workman, and no certain way has heretofore been devised for cutting two bevel-gcars exactly alike by a system of actual measurement in the gear-cutting machine itself. In my machine, aftcr one gear has been out correctly, or even one side of a tooth has been cut, a recordcan be made of the necessary amount of set-over, and ever after that particular size gear can be cut exactlywithout further experiments. For this purpose I arrange upon the end of the shaltj a toothed wheel, 2', fitting loosely on said shaft, which can be held firmly in position by means of the latch-lever t" and locking-button 2'. (Shown in full lines in Fig. 3.)

On the end of thc shaftf is firmly secured the crank-lever k, to the lower end of which is hinged the crank l. The upper end of the crank l is hinged to the rod 122, projecting through a sleeve, 7r, on the lever 70, as shown in Fig. 2. The rod m terminates as a pointer orpawl,m,which is adapted to restin a notched plate, m", secured to the outer face of the toothed wheel 1', the pointer or pawl m being actuated toward the wheel i by means of the coiled spring it" within the sleeve k, as shown.

' the outer and wider end of tooth in a wrong shape. Some means must therefore be used to set over the gear in such position that the cutter may form one side of the tooth, and then to set it in position to form the other. To

accomplish this I release wheel t, and leaving the pointer or pawl m in its seat m, I rotate the notched wheel 1', which then moves the worm f and worm-wheel easufficient distance to bring the tooth of bevel-gear on the arbor 0 of the machine in proper position for the cutter to term one side of the tooth. The wheel i is then looked, and the proper division for toothing the gear proceeds by raising the pawl m out of its seat and rotating the crank l the requisite number of times,thc wheclt'remaining stationary until one side of all the teeth in the bevel-gear has been cut. Theprocess of unlocking wheel t is now repeated, when it is rotated in the contrary direction the proper distance, relocked, and the gearcutting proceeds as before. Thus when it becomes necessary to set over a bevel-wheel to make the side cut the button i is turned to the position shown in dotted lines in Fig. 3, and the latch i is raised out of contact with the toothed wheel 2', and leaving the pawl m in its notch m the wheel t' is turned by the crank l the requisite distance to one side. The teeth of the wheel 1 being numbered from each side of the upper tooth when in its normal position, it is evident that when the proper position of one side of the tooth of gear to be cut is ascertained the wheel i has only to be rotated the same distance from zero in the opposite direction to bring the other side of the tooth in its proper position, and a record can be made, saving any further trials with a gear of the same description; but while the-above arrangement brings the gear-tooth in proper position, a change of position of the cuttingtool a is also necessary upon the cutter-arbor 12. To effect this an extensible collar made in two parts, nand n, is used,as shown in Figs. 1,5, and 8. The two parts ofsaid extensible collar are composed of an outer shell, n, having a male screw-thread fitting within a corresponding fcmale screw-thread in the part n, which latter is made stationary on the arbor n by means'of a key or other "equivalent device, and made to rest against the collar n on the shaft a. On the periphery of the stationary part n is made a zero-mark, and on the periphery of the adjustable part a is a uniform series of numbered lines lengthwise upon its surface.

The end of the cutter-arbor n is screw-threaded, as shown in Fig. 8, and there provided with a nut, a and sleeve n located between said nut and the cutting-tool n. The requisite distance necessary to move the cutter having been determined, the nut a is loosened, and the parts a n expanded or contracted to the necessary point, after which the nut ti is again tightened and the machine is ready for work. Like the device for moving the gear-wheel, so this device for changing the position of the cutter can be made a matter of record, so that it can ever afterward be adjusted with-certainty upon the same description of bevelgears. Furthermore, it is essential that the rotary cutter a should be in a plane passing through the center of the arbor c of the machine which carries the gear d to be out. The method of effecting this in common use is to turn the center arbor to a point at its outer l t al sharp-pointed strip of metaho, as shown. The

other end of the rod has a shoulder, 0', at a proper distance from the end of the shank 0 The device, after being properly fitted to the machine and adjusted by actual experiment, is used by inserting the shank 0 up to its shoulder 0" in a socket bored out in the bearing N of the cutter-arbor, as shown by dotted lines in Fig. 5, and the cutter set so that the center of its cutting-edge coincides with the sharp edge of the metal strip or gage 0. A slot, o is made in the strip 0 to allow of its adjustment for different diameters of the cutters. Another careful adjustment needs to be mude-namely,the depth ofcut for the teeth for gear-wheels; and in practice this is so difficult that only by the aid of special gages made by experts can the average workman set a gear-cutter to the proper depth; but by the mechanism described below this machine can be set with mathematical exactness by anymechanic capable of running the machine. This mechanism consists of a diahp, secured to the bearingp, and usually made in one piece with it. A finger or pointer, 12, loosely embraces the crank-shaft 11', one end of the pointer p being split or sawed through, and provided with a clamping-screw, p so that it can be clamped to turn with the shaft 19' or loosened to turn on it. The dial p is marked with zero at its central top edge, and has a series of lines upon its face to correspond with thousandths of an inch of elevation of the cutter-arborand its attachments. In practice the gearing is commonly so arranged in relation to theelerating-screw qthatacompleterevolution of the crank-shaftp actuating it raises or depresses the cutter and its appendages one-eighth of an inch. The dial then having one hundred and twenty-five divisions, each division will correspond with one thousandth of an inch elevation. The setting for depth of tooth then proceeds as follows: The cutter and gear to be out being in place, the cutter is raised under the gear till its outer edge or circumference is touched. The pointer p, loosened upon the crank-shaft p',is brought to zero-point and clamped there to the shaft. As the depth of cut for teeth of any given pitch is well known, the cutter needs only to be raised the requisite number of thousandths ofan inch to be in position to make the proper depth ofcut.

When cutting gear of considerable diameter the strain upon the arbor carrying it is very great, and the gear itself is liable to spring, causing the cutter to chatter, with danger of breakage, and making rough work. To prevent such chattering or yielding of the gear that is being cut I use the rim-rest shown in Fig. 4. It consists of a stud, "r, secured to the standard a of the machine, and provided with an adjustable set-screw, r, and check-nut r, as shown. The stud 'l' may either be arranged to be vertically adjustable in a slot, r, in the frontof the machine, as shown in Fig. 1, or

may be bolted to it with adjustment fordifi'erent diameters of gears. The set-screw r, being set out till it touches the gear-rim d, supports the rim and prevents its vibration, by which smoother work is produced than could possibly be done without it.

S is the vertically-adjustable table or carriage, actuated up and down bymeansofbevelgear p on crank-shaft 19" and bevel-gear g on the vertical screw-shaft g, which works in the stationary nut q, as usual. N is the laterally-adjustable cutter-shaft carriage, with its bearings N N, as usual.

The automatic feed mechanism shown in the drawings is similar to that descr'rbed in a pat ent granted to me October 1, 1872, and is not subject-matter in the present application.

Having thus fully described the nature, construction, and operation of my invention, I wish to secure by Letters Patent, and claim- 1. In a gear-cutting machine, thewormwheel 0, in combination with the verticallyadjustable worm-carryin g bracket F, adapted to beadjusted on the standard a by means of set-screw a, and having fastening-screws'g g, as and for the purpose set forth;

2. In a gear-cutting machine, the dividingshaft f its toothed wheel i, recessed plate m, crank-lever k k, pawl m m, hinged crank l, latch 2", and button 2', all combined and ar ranged to operate as and for the purpose described.

3. In a gear-cutting machine, the cutterarbor n and cutter n, in combination with the extensible collar 12. n and fastening-nut a, as and for the purpose set forth.

4. The herein-described centering device for centering the cutter a with the arbor 0, con

sisting of the rod 0, set-screw 0, adjustable pointed strip -o, collar 0', and shank 0 adapted to be inserted in a hole or slot in the bearing N for the cutter-arbor, as set forth.

5. In a gear-cutting machine, the combination, with the crank-shaft p and intermediate mechanism for raising or lowering the carriage S, of the stationary and graduated dial 1) and adjustable index or pointer p, as and for the purpose set forth.

6. In a gear-cutting machine, the vertically and laterally adjustable rim-rest r r r, adapted to be secured to the front of the standard a, and having its set-screw 1' arranged to support the rim of the wheel (I that is to be cut, as set forth.

In testimony whereof I have affixed my signature in presence of two witnesses.

AMOS H. BRAINARD.

- Witnesses ALBAN ANDREN, F. ALLEN.

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