US1001799A

US1001799A - Gear-rolling machine.

Info

Publication number: US1001799A
Application number: US57192210A
Authority: US
Inventors: Harold N Anderson
Original assignee: Individual
Current assignee: Individual
Priority date: 1910-07-14
Filing date: 1910-07-14
Publication date: 1911-08-29
Anticipated expiration: 1928-08-29

Description

H. N. ANDERSON. GEAR ROLLING MACHINE.

APPLIOATION TILED JULY 14, 1910.

1,001,799, Patented Aug. 29, 1911.

4 SHEETS-SHEET 1.

INVENTOR.

BY v

M31? ,Cwiwmh ATTOR H. N. ANDERSON.

GEAR ROLLING MACHINE.

APPLICATION FILED JULY 14, 1910.

1,001,799. Patented Aug.29,19 11.

4 SHEETS-SHEET 3.

IV TIVESSES." 'INVENTOR.

H. N. ANDERSON.

GEAR ROLLING MACHINE.

APPLICATION FILED JULY 14, 1910.

1,001,799, Patented Aug. 29, 1911.

illllllllIlIIIIIIIEIIIIIIIIIIIII A T'I'ORN 1 1'5.

. its face, first a breaking down ra ion.

HAROLD NI. ANDERSON, 0F DAYTON, OHIO.

GEAR-ROLLING MACHINE.

' Specification of Letters Patent. Patented Aug. 29, 1911.

Application filed July 14, 1910. Serial No. 571,922.

To all whom it may concern: 7

Be it known that I, HAROLD N, ANDERSON, a citizen of the United States, residing at Dayton, in the. countyof Montgomery and State of Ohio, have invented certain new and useful Improvements in Gear-Rolhng Machines, of which the followingis a'full,

clear, and exact description.

My invention relates to improvements in" means for forming gear teeth by a rolling process, and has for its object to construct a machine into which a blank gear may be placed, and by a series of operations converted into a finished gear, accurate as to diameter, and thickness, shape, depth and spacing of its teeth, ready for use in all except boring its hub;

Rolling gear teeth has advantages besides its obvious economy. One of these is durability, due to the great density of the metal in teeth so formed. Gears rolled by my method, having teeth of correct shape and uniformly spaced, run with comparatively little noise.

Briefly, my improvement consists of means for rotating a blank, preferably heated, and pressing toothed rollers against roller and then a finishing roller. After this, all superfluous metal is removed from the sides of the gear While it is still in the machine. To secure uniform spacing, and eliminate the possibility of too few or too many teeth being formed, the toothed rollers and blank are geared together, which, assuming the rollers to be accurately cut and the teeth of the finishing roller correctly shaped, insures teeth of correct shape on the blank. The effect of slight inaccuracies in the toothed rollers is'minimized or entirely removed, by driving the blank at a speed neither a factor nor multiple of that of the rollers, thereby operating upon each tooth of the blank by successively difl'erent teeth in the rollers. Re

versing the'direction of rotation, after the process is practically complete, also improves the product.

My invention is not limited, inv its broader aspects, to the specific construction shown, except as requiredby the scope of the appended claims, nor is it limited to a mec anism for formingspur gears.

In the accompanying drawings, Figure 1 is a plan of one form of inachine,Fig, 2 is a front elevation, and Fig. 3 a rear elevation.

being keyed thereon.

on a shoulder formed Fig. '4 is a section on line A A Fig. 1, and F g. 5 a section on line B B, Fig. 4. Fig. 6 is the same as Fig. 1 except that the blank is being. operated on by the breaking down roller. igs'. 7 and 8 are details of the shearing tools shown in Figs. land 6. Fig. .9 is a detail of the chuck blank.

for holding the Figs. 10, l1 and 12 are details of a modified method of displacing and removing superfluous metal. Figs. 13 and 14 are details of another method of removing, superfluous metal.

Similar numerals and letters referrto like parts throughout.

Referring to the drawings, 1 is a bed plate on which bearings 2 and 3 are mounted.

Shaft 4, journaled in the bearings, carries gears 5 and 6 and the finishing roller 7, all Anadjustable plate 8 carries bearings. 9 and-10 and shaft 11, on whlch is keyed gear 12 and the breaking down roller 13. Bolts 8" secure the bearings to plate 8, whlle bolts 8* secure the plate to base 1. A feather 8 on the plate, fits in groove-1 and insures proper alinel'nent of shaft 11. An idle gear 14 connects the two shafts. This gear rotates on a bush 14- which is mounted on bolt 14 and clamped between the base plate and an arm 14, the other end of the arm being loosely mounted on shaft 11, thereby maintaining a proper distance between

gears

12 and 14. lVhen the plate 8 is moved, the bolt 14 follows the curved slot 1", keeping gears 5 and 14 properly enmeshed. After the plate 8 is in its proper position, the

bolts

8 and 14 are drawn up tightly.

.A plate 15-rests upon the base 1 and is adapted to oscillate slightly, the construction of itspivot being such as to permit of longitudinal movement of the plate,.as well as lateral adjustment of both pivot and plate. A sleeve 16, part of the pivotal scheme, passes through 1 in the base, afiange on the sleeve resting in the upper part ofthe opening. The sleeve is laterally adj ustable and its position is maintained by set screws 1". It is further secured by a. collar 16 screwed on its lower end. A pivot 17 passes through this sleeve and has a collar 17 screwed on its lower end. The head of the pivot, 17", is squared and affordsa guide for the bifurcated end, 15, of the plate 15, the extensions 17 holding-the plate down.

an elongated opening hand wheel. A lateral projection 15 is held A rod 18 passes lengthwise through the ,plate and screws into a tappedhole in the head 17"; collars 18 on the rod move the plate when the rodis turned. The end of the rod is squared to receive a wrench or down to the plate 1 by a bolt passing through a large hole in the plate 1 and having awasher, larger than the'hole, underneath. This bolt isleft loose enough to perinit the plate 15 to slide. Theoscillatlng movement of the plate 15- is controlled by a

hand wheel

19,9. screw 20 and collars 20. The depending lug 15, against which the collars act, has a horizontally elongated {opening through which the screw passes.

This-bearing is adapted to be moved longi-- tudinally on the plate 15, by a screw 28, carriedby pillar 15 and turned by ahandwheel 28. The pillar 15 is carried by plate 15'. ,The enlarged end, 28, of the screw, turns freely in a recess formed in the plate 26 secured by screws to the end of shaft 26.

' A' feather on the bottom of bearing 25,

slides in a suitable groove in the plate 15. After the blank is clamped between the disks, (see F ig. 5) the bolts 25 (see Figs.,1,

2 and 6) are drawn tightly, after which the screw 28 may be slacked slightly. End thrust in shafts 22' and 26 is taken care of by their flanges 22'and"26 Notches 22 and 26 -in these flanges afiord means for holding or rotating the shafts with a suitable wrench. g

The disks 24 -and 27 are formed with the object of giving support to the web and rim of the blank. With that in view theyhave

projections

24 and 27?, respectively, adapted to press against the web and support the under side of the rim. As the rim will naturally hug these projections very tightly by. the time the gear is finished, they are made slightly conical to reduce friction between the rim and the sides of the projections, thereby facilitating removal of the blank. Since tapering the projections makes removal of the blank easier, it follows that if the taper of one projection is greater than that of 'the other, the blank will separate from the one having the greatest taper more readily than from the other. --Referring to Figs. 5 and 9, more especially the latter, it will be seen that the taper q'f2 1 is greater than that of 27. The first step in removing the finished gear is to slack bolts 25" and draw back the bearing 25, and parts carried by it, thereby drawing the disk 27 away from the disk24. From the foregoing it is clear that the blank will cling to the projection 27, from which it can be forced without injury or distortion, by 'turning the threaded ring 27*. The object ofhaving theblank cling to 27 is that, as it is driven bythe projection 24 through the medium of theblank, the shaft 26 and all parts carried thereby will cease to revolveas soon as theblank is separated from the pro.- jection 24:, thus permitting theremoval of the blank 1n the manner already described, without stopping the machine. The rings 24..a11d 27 are part of and included in the termdisk as applied tomembers 24 and 27. Each one has suitable wrench notches cut .in its periphery. The prime function of these rings is to support the sides of the rim of the blank, but they also furnish a limited adjustability to the disks as a whole, whereby variations in. the width of rim or thickness'of web in the blanks may be compen sated for. When a blankis being inserted the rings may be retracted, and after the blank has been clamped between the projections'24 and 27 the rings are screwed up against the sides of the rim. It wi1l-be noted (see Fig. '9) that the threads cut on the twofportions ofeach disk are opposite, e., the thread on the shank is'right hand and that for the ring left hand, which tends to tighten the shank in the shaft as the ring is turned to force the gear off. The screw connection bet-ween the disks and their respective shafts permits of changing the former for different sizes of blanks, holes 24 and 27 being for a wrench to fit into- In Fig. 6 the first step of 'my'method is' against the teeth of the breaking down roller by means of the hand-wheel and screw, 19 and 20, assuming the shaft 4 to'be rotated in the. direction of arrow, by 'means not shown. The teeth of this roller are preferably sharpv (see Figs. 2 and 4:). It

will be noted that inasmuch as the axes of thebreaking down roller and blank are not parallel, as seen in Fig. 6, the former is made slightly conical. Also notev that the center of pivot 17 is in line with the rear.

edges of gears 6 and 23, which keeps the pitch-lines of these gears practically touching, although there is a slight radial displacement ofgear 23 due to pivoting of the plate 15. The set screw 29, engaging the side of bearing 21'limits themovement of plate 15 and thereby limits the depth of the teeth formed by the gear 13. hen this part of the process has been completed, the plate 15 is swung to the right, forcing the blank against the finishing roller 7 the set screw 30 limiting thomovement of the plate in this direction, thereby limiting the depth of the finished teeth. When the set screws 29 and '30 are properly set, especially the latter, uniform and correct diameters are assured in. the finished gears. In the pres ent machine, gear 6 and

rollers

7 and 13 have 73 teeth each.

Gears

5, 12 and 14 have each'the same number of teeth, therefore the shafts 4: and 11 rotate at the same speed. Gear 23 having 45 teeth, it necessarily'follows that 45 teeth will be formed on the blank. The least common multiple of a5 and 73 being their product, it follows that the blank will revolve 73 times before a given tooth on either roller will enter a given space in the blank a second time, which tends to eliminate the effect of inaccuracy in the rollers. A gear with more or fewer teeth may be substituted for gear 23 and will of course increase or diminish the number of teeth formed in the blank accordingly. When such change is made the pivot 17 and plate 8 will have also to be moved.

A reasonable amount of looseness, commonly called backlash, is desirable between the teeth of gears; the amount of backlash usually allowed varies according to the character of the gears and the use to which they are put. In high grade machinery, the backlash is usually very slight, in some cases there is practically none, and in making gears for such machinery, it is not only im portant to make them accurate, but the backlash should be uniform and of knownamount. Before starting to roll a blank, the pivot 17 should be adjusted so that gears 6 and23 are enmeshed to the proper depth. There is a slight radial movement of the gear 23, dueto the plate 15 swinging on the pivot 17; how slight this radial movement is, in the machine illustrated, may be appreciated when it is noted that the.total bodily movement of the blank is not necessarilymuch more than twice the depth of the teeth to be rolled, while the distance between the blank and the pivot 17 is several I times as great as the radius of the gear 23.

But, slight as this radial movement is, it may be reduced by'increasing the length of shaft 22, and other longitudinal dimensions thereby affected. While there will be a slight variation in. the distance between the axes of gears 6 and 23, due to the said radial movement, it is obvious that a variation brought about by so small a radial move-' ment, must be so slight as to be almost infinitesimal. Therefore, there-will be substantially no variation in the backlash between the gears 6 and 23.

Since the gear 6 and roller 7 are secured to shaft 4, and the gear 23 and blank are secured to shaft 22, the speed ratio between roller 7 and the blank must equal that between gear 6 and 23. The pressure neces-' sary to clampthe blank between disks24 and 27, creates considerable frictionbetween the

flanges

22 and 26 and the ends of their respective bearings, which tends to retard the shaft 22, this tendency being overcome by the gears 6 and 23. Where a blank is rolled by rotation in one direction only, the thickness of the teeth thereby formed will naturally equal the widthof the spaces between teeth in the tooth-forming roller; in other words there will be no backlash between the blank so formed and the roller that formed it. This being the case, if the direction of rotation is reversed, the shaft 4 being the driving shaft, and assuming there is some backlash between the gears 6 and 23, the blank will drive the shaft 22. But, owing tothe retarding influence above referred to, and in view of the malleability of'the teeth on the blank, continued rota tion in the reverse direction will. gradually reduce the thickness ofthe teeth on the blank until they attain a thickness which will permit the gear 23 to resume itsyoflice as driver for shaft 22. Reversing the direction of rotation 3.150 eliminates any tendency there may be for one side of the teeth to be different from the other. At just what point in the operation reversal should first occur, and its frequency, should be deterinined'by .the results; it has been found that one reversal, when a blank is produces good results.

The depth of enmeshment of gears 6 and 23 being "invariable, or substantially invariable, their speed ratio must be fixed. or substantially so; this being so, the lineal velocities of the pitch-lines on the roller 7 I and the blank, 2'. (2., imaginary lines on each which will touch when the teeth on the blank have attained their proper depth, and roll together like two cylinders rolling in contact without slipping, must be substantially equal, Whether the blank is engaged with the roller 13, With'the roller 7, or is any where between those extremes.

Although, in the machine illustrated, gear 6 and

rollers

7 and 13 have the same number of teeth, it is not necessary for such to be the case. Nor Will the number ofteeth formed in the blank always equal the number of teeth, in the gear 23. The gear 6 and roller, 7 may have a different number of teeth, provided their pitch-diameters are the same; their pitch-diameters being the same, it is obvious that the pitch-diameter of the blank will equal that of gear 23; it is equally obvious that the number of teeth formed in the blank will bear the same relation to the number of teeth in the roller 7, that the number of teeth in the gear 23 bears to the number of teeth in the gear 6. Therefore, though the pitch-diameters of gear 6 and roller 7 are 'the same and the pitch-diameter of the blank is the same as that of gear 23, it follows that the number of teeth formed in theblank will equal the practically finished,

number of teeth in gear 23 only when the number of teeth in the gear 6 equals the number in the roller 7. The foregoing is based upon the

shafts

4 and 22 being parallel when the pitch-line of the blank touches .the pitch-line of roller 7.

While the pitch of the teeth in the roller 13 should be the same as that of the roller 'Z,'it is'not essential that the rollers have an equal number of teeth; the lineal velocity of the pitch-line of roller 13- must equalthat of roller 7 however. Clearly, this desired velocity .can be attained by proper selection of

gears

5, 12 and 14. After teeth on the blank have been rolled to proper shape and depth, the plate 15 is moved by the rod 18 till the sides of the rotating blank are brought against first one and then the other shearing tool 31, by which, superfluous metal is removed from the blank.

Figs. 10, 11 and 12 show a modified method of disposing of superfluous metal,

. wherein the finishing roller is confined between two disks 7 flaring slightly from the baseto the ends of the teeth of the finishing roller, the flare increasing beyond that point. This is best illustrated in Fig. 11 which is rather more of a'diagram thana figure. The object of the disks is to press or displace the superfluous metal to a pointbelow the base of the teeth on the blank, from where it is sheared by the tools 31.

Figs. 13 and 14: show another modification, in which disks 7 shear the superfluous metal and force it to a point below the roots of the teeth on the blank, from where it is removed by the shearing tools 31. The

tools

31 and 31 may be dispensed with and the superfluous metal removed by other means after being partially disposed of, as described, by the disks.

While the forms of mechanism herein shown and described constitute a preferred form of embodiment of the invention, it is to be understood that other forms might be used, provided they come within the scope of the claims which follow.

What I claim is as follows:

1. In a gear rolling machine, the combination of means for supporting and rotating a gear blank, a toothed breaking down roller and a toothed finishing roller, means for producing relative movement of approach between the respective rollers and the blank, contemporaneous with and for the purpose of forming teeth on the blank, means for rotating the said rollers, and means for maintainin predetermined, substantially fixed, 'spee ratios between the blank and each of the said rollers.

2. In a gear rolling machine, the combination of means for supporting and rotating a gear blank, a toothed breaking down roller and a toothed finishing roller, means for noomoe producing relative movement of approach between the respective rollers and the blank,

contemporaneous with and for the purpose of forming teeth on the blank, means for rotating the said rollers, means for maintaining predetermined, substantially fixed, speed ratios between the blank and each of the said rollers, and means whereby the rollers act upon the blank'singly.

3. In a gear rolling machine, the combina-- tion of means for sup orting and rotating a gear blank, a toothed reaking down roller and a toothed finishing roller, means for producing relative movement of approach between the respective rollers and the blank, contemporaneous with and for the purpose f of forming teeth on the blank, means for ro- 5 tating the said rollers, means for maintaining predetermined, substantially fixed, speed ratios between the blank and each of the said rollers, means whereby the rollers act upon the blank singly, and adjustable stops for limiting the depth of the teeth formed upon the blank.

4:. In a'gear rolling machine, the combination of means for supporting and rotating a gear blank, a toothed breaking down roller and a toothed finishing roller, means for producing relative movement of approach between the respective rollers and the blank,

contemporaneous with and for the purpose of forming teeth on the blank, means for rotating the said rollers, and means for maintaining predetermined, substantially fixed, speed ratios between the blank and each roller, said latter means I being constructed so that the revolutions of the blank are neither a factor nor a multiple of those of either roller, whereby to operate upon each tooth ot'the blank by successively different teeth on said rollers. I

5. In a gear rolling machine, the combina-- tion ofmeans for supporting androtating a gear blank, a toothed breaking down roller and a toothed finishing roller, each adapted to act upon the face of the blank, means for rotating the said rollers, means for maintaining predetermined, substantially fixed,

speed ratios between the blank and each of the said rollers, and means for removing surplus metal from the blankbeforerem-ovand means for removing surplus metal from the blank before it is removed from its supporting means.

7. In a gearrolling machine, the combination of means for supporting and rotating a gear blank, one or more toothed rollers adapted to roll against the face of the blank for the purpose of forming teeth thereon,

- tion of means for supporting and rotating a .gear blank. one or more toothed'rollers adapted to roll against the face of the blank tor the purposeot forming teeth thereon,

means for forcing surplus metal from the sides of the teeth toward the axis of the blank, and a tool for shearing said surplus metal from the blank.

10. In a gear rolling machine comprising one or more tooth-forming rollers and means for causing them to act upon a rotating gear blank, two oppositely disposed r0 tatable disks, and means for clamping the blank between them, said disks being adapted to clamp the web and the rim of the blank, and support the under side of the rim, the construction of the disks and their supports being such as to afford an unobstructed space between the disks.

11. In a gear rolling machine comprising one or more tooth-forming rollers and means for causing them to act upon a rotating gear blank, two oppositely disposed rotatable disks adapted to support the blank, means for clamping the blank between them,

' means associ-ted with the construction of said rotatalv: supporting disks, whereby, when the disks are separated, the blank will cling to a predetermined one of them, and

a member carried by the said disk to be used to separate the blank therefrom.

12. In a gear rolling machine comprising one or more tooth forming rollers and means for causing them to act upon a rotating gear blank, two oppositely disposed rotatable disks, each having projections adapted to support the rim of the blank, means for clamping the blank between the said disks, and means associated with the construction of said rotatable supporting disks whereby, when the disks are separated, the blank will cling to a predetermined one of the said disks. i l

13. In a gear rolling machine comprising one or more tooth-forming rollers and means for causing them to act upon a rotating gear blank, two oppositely disposed rotatable disks adapted to support the blank, means for driving one of said disks, means for clamping the blank between them or releasing it without stopping the'rotation of the driven disk, and means associated with the construction of the said disks,wherehy, when they are separated, the blank will cling-to a predetermined one of said disks.

ll. In a gear rolling machine comprising one or moretooth-forming rollers and means for causing them to act upon a rotating gear [driven disk.

15. In a gear rolling machine comprising one or more tooth-forming rollers and means for causing them to act upon a rotating gear blank, two oppositely disposed rotatable disks each having a projection adapted to support the rim of the blank, means for clamping the blank between the said disks, means associated withthe construction of the said disks, whereby, when they are separated, the blank will cling to a predetermined one of them, and a threaded ring carried by the said predetermined disk tobe used to separate the blank therefrom.

16. In a gear rolling machine comprising one or more tooth-forming rollers and means for causing them to act upon a rotating gear blank, two oppositely disposed disks, means for rotatably supporting said disks, means for clamping the blank between them, each disk having a projection which supports the rim of the blank, the disk-supporting means and the clamping means being constructed in a manner which permits of inserting and clamping the blank between the disks, or

releasing and removing it therefrom, without detaching the disks from their supporting means.

'17. In a gear rolling machine, the combination of means for supporting and rotating a gear blank, a tooth-forming roller, means for producing relative movement of approach between said roller arid the blank,

LOO

contemporaneous with and for the purpose of forming teeth on the blank, means for rotating said tooth-forming roller, and

means for maintaining a predetermined, substantially fixed, speed ratio between said roller and the blank 18. In a gear rolling machine, the combination of means for support-ing and rotating a gear blank, a tooth-forming roller adapted to act upon the blank and form teeth thereon, means for rotating said toothtorming'roller, means for maintaining a predetermined, substantially fixed, speed ratio between said roller and the blank, a

shearing tool on each side of the blank, and means for causing each tool to remove superfluous metal fromlthe side of the blank adjacent thereto.

- nect-ing the said roller supporting means pendicular t and blank supporting means for the purpose of rotating the latter, and means for keeping the teeth of the connecting gears at a substantially uniform depth of enmeshment while the teeth are being formed on the blank.

20. In a gear rolling machine, the combination of a tooth-forming roller and means for supporting and rotating same, rotatable means for supporting a gear blank, a support for said rotatable means, the said support being pivotally connected to the roller support, the axis of said pivot being-perthe axis of the blank, and means for S\ inging the blank support on said pivot and bringing the blank into engagement with the roller for the purpose of forming teeth on the blank.

21. In a gear rolling machine, the combination of a toothed roller and means for supporting and rotating same, rotatable means for supporting a gear blank, a support for said rotatable means, the said support being pivotally connected to the roller support, means for swinging the blank support on said pivot and bringing the blank into engagement with the roller for the purpose of forming teeth on the blank, and means for rotating the blank at such speed thatthe lineal velocity of its pitch-line will be maintained substantially equal to the lineal velocity of the pitch-line of the toothed roller.

22. In a gear rolling machine, the combination of a tooth-forming roller and means for supporting and rotating same, rotatable means for supporting a gear blank, a support for said rotatable means, the said support being pivotally connected to the roller support, means for swinging the blank support on said pivot and bringing the blank into engagement with the roller for the purpose of forming teeth on the blank, and a stop for limiting the depth of the teeth thereby formed.

23. In a gear rolling machine, the combination of a toothed roller and means for supporting and rotating same, rotatable means for supporting ,a gear blank, a support for said rotatable means, the said support being pivotally'connected to the roller support, means for swinging the blank support on said pivot and bringing the blank into engagement with the roller for the purpose of forming teeth on the blank, a stop for limiting the depth of the teeth thereby formed, and means for rotating the blank at such speed that the lineal velocity of its pitchline will be maintained substantially equal to the lineal velocity of the pitch-line of the toothed roller.

24. In a gear rolling machine, the combination of a tooth-forming roller and means for supporting androtating same, rotatable means for supporting a gear blank, a support for said rotatable means, the said support being pivotally connected to the roller support, the pivot being laterally adjustable with reference to the axial line of said tooth-- forming roller, and means for swinging the blank support on said pivot and bringing the blank into engagement with the roller for the purpose of forming teeth on the blank.

25. In a gear rolling machine, the combination of a tooth-forming roller and means for supporting and rotating it, rotatable means for supporting a gear blank, a support for said rotatable means, said support being pivotally connected to the roller support, means for swinging the blank support upon said pivot and bringing the blank into engagement with the roller for the' purpose of forming, teeth on the blank, and gears connecting the roller and the blank supporting means, one of said gears being on the axial line of said pivot.

26. In a gear rolling machine, the combination of a tooth-forming roller and means for supporting and rotating it, rotatable means for supporting a gear blank, a support for said rotatable means, said support being pivotally connected to the roller support, the pivot being laterally adjustable with reference to the axial line of said tooth-forming roller, means for swinging the blank support on said pivot and bring-- ing the blank into engagement with the roller-for the purpose of forming teeth on the blank, and gears connecting the roller and blank supporting means, one of saidv gears being on the axial line of said pivot.

27. In a gear rolling machine, the combination of two tooth-forming rollers, means for supporting a gear blank between said rollers, means for rotating the rollers and the blank, means for maintaining predetermined, substantially fixed, speed ratios between the rollers and the blank, and means for moving the blank into engagement selectivelywith the said rollers for the purpose of forming teeth on the blank.

28. In a gear rolling machine. the combination of .two tooth-forming rollers, a support adapted to carry a gear blank and permit its rotation, said support being pivotally mounted between said rollers, means for swinging said blank carrying support upon said pivot to bring the blank into engagement selectively with the rollers for the purpose of forming teeth on the blank, and means for rotating said rollers.

29. In a gear rolling machine, the combination of two tooth-forming rollers, a support adapted to carry agear blank and permit its rotation, said support being pivotally mounted between said rollers, the pivot being laterally adjustable with reference to said rollers, means for swinging-the blank carryingsupport upon said pivot to bring the blank into engagement selectively with port adaptedto carry a gear blank and permit its rotation, said support being pivotally mounted between said rollers, means for laterally adjusting one of said rollers, means for swingin said blank carrying support upon said plvot to bring the blank into engag'ement selectively with the rollers for the purpose of forming teeth upon the blank,

and means for rotating said rollers.

31. In a gear rolling-machine, the combination of two tooth-forming rollers, one of said rollers being laterally adjustable, asupport adapted to carry a gear blank and permit its rotation, said support being pivotally mounted between said rollers, the pivot being laterally adjustable witlnrefcrence to said rollers, means for swinging said blank carrying support, upon said pivot to bring the blank into engagement selectively with the rollers for the purpose of forming teeth upon the blank, and means for rotating the said rollers.

32 In a gear rolling machine, the combination of two tooth-forming rollers, means for supporting .a' gear blank between said rollers, means for rotating the rollers and blank, means for maintaining predetermined, substantially fixed, speed ratios between the rollers and the blank, means for moving the blank into engagement selectively with the said rollers for the purpose of forming teeth on the blank, and stops for limiting the depth of the teeth formed upon the blank.

33. In a gear rolling machine. the combination of two tooth-forming rollers, means for rotating them, a support adapted to carry a gear blank and permit its rotation, said support. being pivotally mounted between said rollers, means for swinging the blank carrying support upon said pivot to bring the blank into engagement with the rollers for the purpose of forming tceth on the blank, gears connecting one of said rollers to the blank carrying. support, one of said gears being on the axial line of said pivot.

34. In a gear rolling machine, the combination of two tooth-forming rollers, mounted parallel with each other, a support adapted to carry a gear blank and permit its rotation,-said support being pivotally mounted between said rollers, means for swinging said blank carrying support upon said pivot to bring the blank into engagement with the tooth-forming rollers, one of said rollers being slightly conical to compensate for the relative obliquity of the axis of the blank whenengaged therewith, and means for rotating the rollers.

35. A gear rolling machine, comprising one or more tooth-forming rollers, means for causing them to act upon a rotating gear blank, and means for supporting the blank, comprising two oppositely disposed rotatabl'e disks, means for supporting said disks and means for clamping the blank between them, the configuration-of the faces of the d sks being such-as to positively prevent displacement of the blank in a direction perpendicular to its axis, the construction of the disks and their supports being such as to atford an unobstructed space between them.

' I 36. A gear rolling machine comprising one or more teeth-forming rollers and means for causing them to act upon a rotating gear blank, and means for. supporting and driving the blank comprising a positively driven disk having a conical projection, an. op-

positely disposed rotatable disk also havmg a conical projection, and means for movmg the latter disk for the purpose of clamping the blank between the two disks,

the conical projections being adapted to clamp the web of theblank and support the rim thereof, the projection from one of said disks having a greater angle of taper than the other.

37; A gear rolling machine comprising one or more tooth-forming rollers and means for causing them to act upon a rotating gear blank, and means for supporting and driving the blank comprising a positively driven disk having a conical projection, an oppositely disposed rotatable disk also having a conical pro ection, each of said disks havmg an annular ring screwed on its periphery, the rings thereby being adjustable with reference to the respective projections, and means for moving the rotatable disk for the purpose of clamping the blank between the disks.

38. In a gear rolling machine. the combination of means for 'rotatably supporting a gear blank, one or more tooth-forming rollers adapted to act upon the blank for the purpose of-forming teeth thereon, a tool adjacent to said blank, and means for moving the blank longitudinally and bringing it into engagement with said tool for the purposeof removing superfluous metal from i the blank.

39. In a gear rolling machine, the combination of means for rotatably supporting a gear blank, one or more tooth-forming rollers adapted to act upon the blank "for the purpose of forming teeth thereon, a tool on each side of the blank, and means for moving the blank longitudimilly and bringing it into engagement selectively with the said tools for the purpose of removing super-- supporting means and tooth-forming roller, whereby, when one is rotated the other is p also rotated, and means whereby the. lineal velocity of the pitch-line of the blank is maintained substantially equal to the lineal velocity of the pitch-line of the tooth-forming roller during the process of forming teeth on the blank.

41. In a gear rolling'machine, the combination of a tooth-forming roller, rotatable means for supporting a gear blank, means for producing relative movement of approach between said roller and the blank, contemporaneous with and for the purpose of forming teeth on the blank, gears con,- necting the roller and the blank supporting means, and means for keeping the depth of enmeshmentof said gears substantially uniform, whereby, the backlash between said gears may be substantially invariable.

42. In a gear rolling machine, the combination of rotatable means for supporting a gear-blank, a toothed breaking-down roller and a toothed finishing roller, each adapted by virtue of relative movement of approach between itself and the blank to act upon the blank and form teeth thereon, means for producing said relative movement. of approach, and means for connecting the blank supporting means to the breaking-down roller and the finishing roller,- whereby, when one is rotated, all are made to rotate, and means whereby the lineal velocity of the pitch-line of the blank is maintained substantially equal to the lineal velocity of the pitch-line ot the breaking down roller and the finishing roller.

43. In a gear rolling machine, the combination of a rotatable means for supporting a gear blank, a toothed breaking-down roller and a toothed finishing roller, means for producing relative movement of aproach .between the respective rollers and the blank, contemporaneous with and for the purpose of causing said rollers to form teeth on the blank, gears connecting each roller to the blank supporting means, and means for keeping thedepth of enmeshment of the gears substantially uniform, whereby, the backlash between said gears .may be sub- 'stantially invariable.

44. In a gear rolling machine, the combination of means for supporting and rotating a gear blank, a toothed member adapted to form teeth on said blank, means for pressing the toothed member and blank together for the purpose of forming teeth on the blank, and means whereby the lineal velocity of the pitch-line of the blank is maintained substantially equal to the lineal velocity of the pitch-line of the toothed'member during the process of forming teeth on the blank.

In testimony whereof I aflix my signature in the presence of two subscribing witnesses.

HAROLD N. ANDERSON.

\Vitnesses:

F. K. FASSE'I'I, J. B. HAYWARD.