US2111170A - Machine for finishing gears - Google Patents

Description

March l5, 1938. R. s. coNDoN n MACHINE FOR FINI-SHING GARS 11 sheets-sheet 1 Filed Sept. lO, 1935 Srwentor 'ef/ J @2M/a' Gttorneg MACHINE FOR FI NISH1NG GEARS Filed Sept. 10, 1935 11 Sheets-Sheet 2 Bnnentor by? afm/W l Gttorneg March 15, 1938. R. s. CONDON- MACHINE FOR FINISHING GEARS 1l Sheets-Sheet 5 Filed Sepb. l0, 1935 hl, NN MMM. Nw m www m QJ N, ww N QS bmw @nw @N v. U7 /\\f www* .r lwlmmmwllllvlll: 1- m Cttorneg March 15, 1938. R. s. coNDoN 2,111,170

vMACHINE FOR FINsHlNG GEARS Filed Sept. 10, 1955 l 11 sheets-Sheet 4 mm)- \Q\% NN km, N wr/ww, www uw a y l -i i -4 n----l,--}-ll-|l ---i m I\-Tl www {VWG} -L m v N mn NS@ SQ @W g@ Mara. 15, 1938.. R s. CONDON 2,111,170

MACHINE FOR FINISHING GEARS F11ed sept. 1o, 1955 11 sheefs-sheet 5 Snnentor March15,.1938. RSCOWON www MACHINE FOR FINISHING GEARS Filed Sept. l0, 1935 l1 Sheets-Sheet 6 Zmventor im@ f Cttorneg March l5, 1938. Rfs. coNDoN MACHIANE FOR FINISHING- GEARS Filed sept. 10, 1935- 11 Sheets-SheefI 7 wy- QQ Q h QN RN Nw ff, um j (ttorneg .W 15, 1938. R. sncoNDloN v H3170 lMACHINE FOR FINISHING GEARS Filed sept. 1o, 1955 11 sheetfsfsheet's I f// J @add/gum Gftorneg March l5,` 1938. R. s. coNDoN 2,111,170

MACHINE FOR-FINI5H1NG GEARS Filed Sept. l0, 1955 11 Sheets-Sheet 9 March 15, 11938.'

R. S. CONDON MACHINE FOR FINISHING GEARS Fi'led Sept. l0, 1935 ll Sheets-Sheet l0 f F" f y' Smaentor mtomeg March 15, 1938. R. s. coNDoN 2,111,170

I MACHINE FOR FINISHING'GEARS Filed sept. 1o, 1955 11 sheets-sheet 11 #for mommy Patented Mar. 15, 1938 PATENT OFFICE 2,111,170 MACHINE FOR FINISHING GEARS 'Robert s. condon, menester, N.

Gleason Works, Rochester, N. Y.,

of New York A l -22 claims. The present invention relates to machines for finishing and testing gears, particularly to machines of the combination type for lapping and testing or burnishing and testing gears. In a 6 4more specific aspect, the invention relates to ma,

chines for lapping or burnishing and testing .spiral bevel and hypoid gears.

One of the principal objects of this invention is lto provide an automatic machine for lapping 10 and burnishing spiral bevel and hypoid gears,

which will operate according to the basic principles of the U. S. patent 'ci' Alton P. Slade, No.V

1,796,484 of March 17,V 1931 and which will be of simpliiled and improved construction as -coml5 pared with. the automatic machine or the joint U. S.'patent of myself, E. W. Bullock and. Eyvind v Finsen, No. 1,881,999 of October 11, 1932.

StillA another object of the invention is to provide a machine ofthe type in which the relative positions of the meshing gears are. changed during lapping in order to effect the lapping operae tion and to obtain a suitable' localization ol tooth bearing, in which the amount of back-lash between the gears may be controlled and, if desired,

maintained substantially constant `throughout lapping. a

, Another object of the invention is to provide a gear burnishing or lapping'machine in which the lapping or burnishing operations on opposite Sil-'sides of the teeth can be eiected at different rates. Still another object ofthe invention is tc provide in a combined burnishing or lapping and testing machine, improved `means for both protecting the operatoragainst injury and preventing damage to the gears being-burnished, lapped or tested;

Other objectsof the invention will be apparent hereinafter from the specification and from the v 10 recital of the appended claims.

in the machines' of the type described in Patent Nos. 1,796,484 and 1,881,999, lapping or burnishing of a pair of spiral bevel or hypoid gears is accomplished by rotating the pair of gears to 4 5 be lapped or burnished in mesh land simultaneously moving one ofthe gears in directions both longitudinal of the axis of the other gear and transversely thereof.- A

In burnishing, theteeth of one gear are bot- 50 tomedin the tooth spaces of the other and are held in engagement by spring pressure and as the one gear moves longitudinally and transversely of the other gear, the springs yield and cramping of the teeth of the gears is avoided. 56 In lapping, however, it-is not desirable to mesh gear. This has meant, of course,

jthe gears will be more cordingly the lapping a'ction will be reduced.-

should be oscillated Y., assignor a corpi'iration4 y 'Application september 1o, 1935, sensi No. 39,952

the gears so that the teeth. of one bottom in the tooth spaces of the other.

It has been necessary heretofore, then, to set up the gears with sumcient back-lash to avoid interference at the ends of the teeth as one gear moves first toward the small end and then toward the larger end of the teeth oi' the other that in the centrai position, the. amount of back-lash between than necessary'- and ac- In the machine of the present invention, provision is made for mechanically and-automatical-l ly maintaining a uniform amount of back-lash between the gears during lappingin all positions of their relative movemen Thus the most effective lapping action can be obtained throughout the whole of the lapping operation and .therefore the speed of the lapping operation can be increased.

. In the machines of both the patents mentioned, the relative longitudinal and transverse movementsbetween the meshing gears are effected by oscillation of a carrier in which one of the gears is eccentrically mounted. This same construction is retained in the present machine. In order/ to obtain the desired tooth bearing on opposite sidesv 'of the teeth, practice has demonstrated that`it isdesirabletorun the meshinggears together nrst in one direction and then in the other and that during rotation in opposite directions, the carrier through dierent angles and -at diierent rates. This is becayse of the difterence in the eiects' of lapping or burnishing on the drive and coast sides of thegear teeth.

In the machines of both prior patents mentioned, two different cams were employed to produce the diering oscillating motions required` -for the burnishing or lapping of the opposite oscillating motion of the gear carrier, and then at the end of a given period-the machine'was stopped. In the burnishing or lapping of either side of the gear teeth, the carrier-control cam made one or more revolutions and hence in the lapping or burnishing of the two sides of the teeth, the cam shaft made a plurality of revolutions. Hence, it was necessary in both prior machines to employ an automatic stopping mechanism having a counter arrangement to stop the machine when the lapping or burnishing operation was completed.

In the preferred embodiment of the present invention, a single'cam is employed to control the oscillating motions of thecarrier in the finishing of both sides of the gear teeth. One-half of this cam controls the oscillating motion of the carrier during finishing of the drive side of the teeth and the other half of the cam controls the motion of the carrier during finishing of the coast side 0f the teeth. It is not necessary to shift from one cam to another between the operations on the opposite sides of the teeth. Moreover, in a single revolution of the cam shaft, theY whole cycle ofoperation of the machine is completed.

Hence the expensive automatic stopping mecha- In the embodiment of the invention illustrated.

i in the drawings, the gear spindle is journaled in a sleeve or quill which is axially movable in the oscillatable carrier. For lapping, this sleeve is moved axially to maintain a controlled amount of back-lash by oscillation of a screw which threads into a nut that is secured to the sleeve. This provides a very simple, compact construction. For burnishing, the screw and nut are omitted but the' gears are held in mesh with the teeth of one bottoming in the tooth spaces of the other by coil-springs which operate directly upon the quilior sleeve. This constitutes an improvement in burnishing machine construction, becausethe springs are able to act more directly upon the gears than in the prior machines, and there` is less likelihood of vibration or chatter.

A further improvement of the present machine particularly valuable for lapping, is an improved back-lash brake. This is inthe form of a hydraulic pump driven from the gear spindle. The pump forms part of anopen hydraulic system-and is connected to a sump so that when the pump is in operation, it will pump liquid outAof the sump `and discharge it back into the sump again. The amount of load or resistance to be applied to the gears is determined by the setting oi a relief valve which controls the discharge from the pump. -The greater the liquid pressure required to open the relief valve,fthe greater the resistance to the turning of the pump and, therefore, the greater the resistance to the rotation of the gears, that is, the greater the load applied to them. This type of brake has been found very much more satisfactory than the friction type of brake used on vprevious machines. Friction brakes are liable to wear and if oil or grease get on the friction surface, slippage, or grabbing will occur. The lapping of gears is a precision operation and the improvement in the back-lash brake makes possible a more accurate product.

As indicate invention ma be used forI lapping or burnishing and testing. For testing, the gears are simply run together on center and no oscillating or axial Yout of operative position.

above, then/machine of the pres-ent motions are employed. A guard is, of course, provided on the machine to enclose the gears during lapping or burnishing.` Safety features have been incorporated in the electrical circuit of the machine so that for lapping, the guard must be closed and the oscillating cam must be in operating position while `for testing, the guard must be open and the yoscillating cam must be As a further safety feature, to prevent any possibility of the operator getting'his hands caught` between the gears, during testing, provision is made so that the operator must keep one hand on a push button during the whole of the test in order to keep the machine running. His other hand, of course. will be out of the yway as it will be operating a hand brake to apply the load required to test the gears.

In the drawings:

Fig. '1 is the side elevation, with parts broken away, of a combination burnishing or lapping and testing machine constructed according to the present invention; s

Fig. 2 is a plan yview of this machine;

Fig. 3 is a longitudinal sectional view of` the motions to the carrier and quill, respectively, in

the lapping machine;

Fig. '7 is a section approximatelyon the line l-1 of Fig. 5, showing the cam shaft and details y Aof the drive therefor;

Fig. 8 is a sectional view taken approximately on the line 8 8 of Fig. 7;

Fig. 9 is a view looking at the end of the gear l head and showing the hydraulic back-lash braking mechanism; i

Fig. 10 is a developedsectional view on the line Illl0 of Fig. 9;

Fig. 11 is a sectional view on the line H--I l of Fig. 9;

Fig. 12 is a fragmentary sectional viewshowing g1 detail the mechanism for adjusting the pinion Fig. 13 is a sectional view of the lapping guard, showing the piping for conducting the lapping compound on to the gears and the limit switch which insures that the guard is closed during a lapping or burnishing operation;

Fig. 14.- is a fragmentary view taken at right angles to' Fig. 13 Iand showing details ofthe distributing system for lthe lapping compound;

Figures 15 and 16 are side elevational views of typical cams for controlling the oscillating and axial movements of the carrier and quill, respectively;

Fig. 17 is a fragmentary sectional view on the line I'i-Il of Figure';

. Fig. 18 is a fragmentary sectional view on the line |8-l8 of Fig. '7: f

l JFigures 19A to 24 inclusive are diagrammatic views illustrating how interference will occur during lapping at the ends of the teeth of the meshinggears in the shifting movements of -one mounted, as in previous machines, a head 3| and' burnished," lapped or tested,

detail here. The pinion spindle 36 is'driven from.

the head 46 on the column 32 may be the same spindle 48 ismounted eccentrially in the carrier. 'Ihe carrier is journaled in 'plain bearings 5 4 and..

Fig. 25 is anelectrical wiring diagram. of the machine. s

Referring now to the drawings by numerals of reference, designates the base or frame of the machine. On this base or frame there are a column 32 (Figures 1, 2, and 5). These are adjustable on the base or frame at right angles to one another to bring the gears to be lapped, burnished, or tested into meshing engagement.

Journaled in anti-friction bearings 34 and 35 in'thehead 3| is the drive-spindle 36 of the machine. The pinion of the pair of gears'to be Y or if a special burnishing or lapping pinion is used, that pinion, is secured to the drive-spindle 36. Any suitable chucking mechanism may be employed for securing the pinion to the drive-spindle. In the ma.-

chine illustrated, a hydraulic chucking mecha.-

nism, designated as a whole at 38 is employed for this purpose. is of standardv construction and forms no partof the present invention, it will not be described in a motor 40 mountd in the base of the machine through pulleys 4| and 4 2fand the belting 43 connecting the same.

The column 32 is provided with vertical ways (Figs. 5 and 7) on which the gear head 46 is vertically adjustable. The means for adjusting as employed in the machine-oi. Patent No.

1,881,999-and for that reason will not further be described here.

The gear or driven spindle 48 of the machine is carried in this gear head 46. `It is iournaled on anti-friction bearings 49. and 50 in a sleeve or quill 5| and this quill is slidably mounted in an oscillatable carrier 52 (Figs. 3 and 5). lThe mounting of the spindle 48 in the quill 5| and of the quill 5| in the carrier 52 is such that the laxis of the spindle 48 is offset fromthe axis of the carrier but parallel thereto, 'that is, that 55 formed integral with the head 46.

The gear G to be burnished, lapped ortested or, in case a special burnishing or lapping.,gear is used, that gear, is secured to the driven spindle 48. For securing the gear to the spindle, any suitable type of chucking mechanism may be employed. In the machine illustrated, a standard hydraulic chuckin'g mechanism, 4designated as a whole at 58 is employed, but as this mechanism is of known construction andforms no part of the present invention, it will not further be described here.

Mounted on the column 32 of the machine is l a motor 60 (Flgs.'l, 2, and 7). This motor drives the carrier 52 and, during lapping, the reciprocating quill 5|, as will now be described. The motor is -connectedby a' suitable coupling 6| with a meshes with a worm wheel keyed to a shaft 65.

shaft 62 carrying the worm 53. This worm 68 The shaft 85 is journaled on anti-friction bearingsv 68 and 61 in a bracket 13 which is secured to the column 32.

Splined to the shaft 85 are a pair of" spur change-gears '68 and 69. These are secured against a shoulder formed on the shaft by the nut 10,` which threads on the shaft, .and by the washers 1| and 12. V

'I'hespur-gears 68 and 88 mesh, respectively, with spur-gears 14- and 15 (Fig. '7) which have splined connections, respectively, with the shafts .iournaled on anti-friction As this chucking mechanism e4 (Fig. s) that is..

16 and 11. The gears 14 and 15 are held ontheir respective shafts by nuts' 18 and 19, respectively,

which thread on the shafts and by the washers which cooperate with these nuts.

` The shaft 16 is journaled on anti-friction bear- 5 ings and 8| in the bracket 13. -The shaft 11 is bearings 82 'and 83 in the bracket 13. 'I'here is a spur gear 84 These gears are adapted to be mashed selective.,l

with a spur gear 8 1; (Figs. 7 and 8) that is inte- 88. This sleeve is mounted to 90 .that is journaled on antigral ,with a sleeve slide upon a shaft frictiorrbearings 9| in the bracket 13 and on anti- 15 friction bearings 9 2 in an arm 94 that is secured to the bracket 13 by screws 85.

The shaft 30 has a'worm 96 with it that meshes with a worm-wheel 91 (Figs.

8 and '7). 'I'he worm-wheel 91 is keyed to a 20 .sleeve 88 which forms-'a bearing for a slidable shaft 99. There are two pins |00 and |02 secured in the worm-wheel Y31 to project from one side thereof.

Pivotany mounted at los inthe brackems is 25 a yoke-member |05 having a ldng arm |03 and a' short arm |04. In .the rotation of the wormwheel, the pin |00 isidapted to. engage the long arm |03 of the yoke-member and h pin |02 is v adapted to engage the short arm |04 of said yoke- 30 member, thereby shifting ithe yoke-member alternately in opposite directions about its pivot |06. 'I'he yoke-member carries opposed rollers vlill which engagev in a recess or groove |08 formed betweenthe shoulders |09 and I|0 of the 35 sleeve 88. Thus, as the worm-wheel 91 rotates,

-the yoke-member |05 is rocked ilrst in one direction and then in the other'about its pivot |06 to engage the gear 81 alternately with the gear 85 (Fig. '7) and-with the' gear 84. The gears 84' 46 and drive the gear 81 in the same direction so thatthe worm-wheel 81 is driven in thesame direction regardless of whether the gear 81 is -engaged with the gear 85 or the gear 84, but the worm-wheel 911s driven at one rate when the 45 gear 84 is driving the gear 81 and at a diierent rate when the gear 85 is driving the gear 81.

The external groove |08l in the sleeve 88- is wider than the'rollers |01, which operate therein, for a purpose which will appear hereinafter. 50

'I'ol insure quick shifting of the'yoke-mem'ber |05 and to insure that the gear 81 remains in contact with either the gear 84 or 85, which has previously been-driving it. until the yoke-member has been shifted so that there will be a continu- 55 ous drive to the worm-wheel 91 at 'all times, av

loadand -fire mechanism and a drag-detent are provided.

.The yoke-member |05"is `operated by a load and re mechanism comprising a plunger ||5f60 that is housed in a bore in the bracket 13. This plunger is spring-pressed outwardly by"a coil spring ||6 and it has a V-shaped outer end orhead 8 vwhich engages the V-shaped head H0 of a stud ||1 that is secured in the yoke-member 65 |05. As soon as the yoke-member 805 is rocked past center in either direction', this load and fire mechanism operates to swing it on quickly and positively to the endof its movement.

The bore of the` sleeve 88 is formed with two 70 conical recesses or grooves |20 and |2|. The shaft 80 has a hole |22 drilled diametrically through it. yThere is a pin |23 mounted in this hole that has a conical head |24. 'A sleeve |25 telescbpes on the-pin |23 and thishas a conical head |26. 75

keyed to the shaft 16 and there is a spur gear 85 keyed to the shaft 11 10 formed integral The two headed members are adapted to en' gage in the recesses |26 or |2| depending upon the axial position of the sleeve 68 and they are .pressed apart and into engagement withthese recesses by a coil spring |21. The headsl24 and |26 are pressed by the spring |21 into engagement with one or the other of the recesses |26 As above described, the external groove |68 inv y the sleeve 88 vis wider than the pins |01 which operate therein. Hence, during the rst part 'of the movement of the yoke-member l|55 in either direction, no ymovement is imparted to the sleeve 88 4and gear 81 and it is not until after the yoke-member has passed center and is being thrown on to the end of its movement by the spring pressed plunger ||5 thatv the sleeve 88 and gear 81 start to move. The double headed plunger |24-I25 serves to hold the gear 31 in engagement with whichever of the gears B4 o1; 35 that has been driving it, until the' yoke has passed center. Then the momentum of the'yoke under actuation of the spring-pressed plunger 5 is sufficient to overcome the frictional resistance of the drag-detent |24|25 and the sleeve 88 is moved on into its new axial position. The drag-detent serves to insure that the gear 81 remains in driving engagement thl either the gear 84 or 85 until movement of he yoke on to its new position is insured. Thus assurance is had of a drive at all times to the worm-wheel 91.

The shaft 99 is slidably mounted in the sleeve 98 and in a plain-bearing |36 which is secured in a plate that is secured in 'any suitable manner Ato one side of the column 32. y Keyed to the shaft is a disc ISI on whose hub is mounted a cam |32 which is secured to the disc |3| by screws |33. 'Ihe periphery oi? the disc |3| is.

concentric with the axis of the shaft 99. The

' cam |32 may be of anysuitable shape, one typical form of such cam being shown in Fig. 15.

|35 denotes a roller whichl is mounted upon a stud |36 which is threaded into a cylindrical bar |38. The bar |36 is adapted to slide 'in a tubular guide formed in a bracket |39, which is-se cured to the plate |46 that is secured to the column 32. Either the cam |32 `or the disc |36 may be engaged with vthe roller |35 by shifting the shaft 99 axially. burnishing the l'cam is engage with the roller while during testing the disc is engaged with the roller as will hereinafter appear.

Mounted in the bar |38`at the end opposite that which carries the roller |35, is a stud |42 on which is mounted a roller |43. 'Ihe roller |43 engages one end of a contact-member vor stud |44, that is adjustably mounted in the arm |45 of alyoke-member |46 (Figs. 6, 3 and 4). The yoke member |46 takes its bearing on the periphery of the carrier 52 and is secured to the carrier 52 in any suitable manner to transmit motion to the carrier.

The contact-member |44 is. held in engage- Y mentwith the roller |43 of the bar |38 and the .roller |35 of this bar is in turn held in engager` ment with the cam |32 by a spring (not shown) which operates to urge the carrier in one direction about its axis. the same as shown in the Bullock et al. patent -above mentioned. The contact member |44 is adjusted axiallyin the arm |45 by rotationof ng lapping or .f

The construction may bbethe handwheel |41 which is secured to a shaft |48 that threads into the arm and that abuts at its inner end against the opposed end face of the contact member |44. lThe extremity of the arm |45 is in the form of a Split clamp and -fthe contact member may be secured in any adjusted position in the arm by vtightemmg the clamping lever |49.

Fr'om the above description it will be seen that when the cam' |32 is engaged vwith the roller |35 and the shaft 99 is rotated. the cam |32 will impart a reciprocating movement to' thebar |38 to oscillate the carrier 52 on its axis, "thereby causing the gear to be swung about an axis eccentric of its own axis. Of course, when the disc |3| is .engaged with the roller |35, the car,-

rier will remain stationary despite the rotation of shaft 99 because the discis concentric of the shaft.

. The disc or cam selectively is brought into engagement with the roller |35 by moving the shaft 95 axially. Axial movement of .the shaft is effected by movement of a lever |53 which is plvotally mounted at |51 on the column 32. This lever is formed at its short end with a yoke portion having pins |59 which engage in a peripheral recess formed in the shaft99.

To insure that a cam |32 is engaged with the roller |35 when a pair of gears are to be lapped or burnished and4 that the disc |3| is engaged with the roller when a pair of gears are to be tested, a safety device is provided. This comprises a double-throw switch |96 (Figs. '7 and 25) which is mounted onf the column 32 in such position that the roller |91, carried by its arm |98 is engaged by one of\the pins |59 of the lever |53 to rock the switch arm when the Shaft 99 is shifted in either direction. The function of this switch Will be described more particularly hereinafter.

Keyed to the shaft 99 at one end thereof is a sleeve |56 (Figure 7). 'I'his sleeve is journaled on anti-friction bearings |5| and |52 in the endcap |54 of the bracket |39. Secured to the flange |55 of the sleeve |56 by screws |56 is a cam |5E3.

This cam.l may be of any suitable conformation.'

One typical form of such vcam is shown in Fig. 16.

'I'he cam |56 is adapted to engage a roller |63A which is rotatably mounted upon a stud, |6| The stud |5| is secured in one end of Aa cylindrical bar |62 which is slidable in a cylindrical 4guide formed in the bracket |39 parallel to the guide in which the bar |38 slides.

This bar |62 is of reduced dimension at itsl outer end and engages the half-round endof a contact member or follower |64 which is rotat' operative., In this position its tip. will engage the surface of the arm |66 which is securedto `the bracket |39'(Fig. 7) by screws |61.

'I'he contact member |64 is held in either position of its adjustment by set-screws |68 and |69 which are adapted to engage in longitudinal grooves |10 and formed in the contact-member. 'I'he contact member is held against axial movement relative to the sleeve |63 by the nut |12 which is threaded on the outerend of the reduced stud portion of the contact member.

'I'he arm |65 is p ivotallymounted at |14 (Fig. 5) in a guard |16 and has a'depending portion (Fig. 3) which is keyed to a screw shaft v| 15 which is journaled in suitable bearings in the head 46 and in the guard |16. 'I'he guard |16 is secured to the head. The screw shaft |15 has a threaded portion |11 which engages in a nut |18. This nut |18 is secured in a ring |19 which is rigidly held between the inner end of the quill and a@ spacer member |88 that is secured to the sleeve or quill by screws, |82. The spacer member |88 is also held against axial movement relative to the quill 5| bythe sleeve |84 which is keyed to spindle 48 and which is formed with. a iiange |85 that engages in a circular recess formed in the spacer member |88. The sleeve |84 is heldin position -by the brake-drum |86 which is secured on the spindle 48 against axial movement relative thereto by the nut. |81 that threads onto the spindle.

From the preceding description, it will be apparent that as the cam shaft 99 rotates, the cam |58 (Fig. 7) will impart a reciprocating movement to the bar |62 and this in turn will oscillatethe arm |65 and screw |11 to move the quill 5| axially to and fro in the carrier 52, lthereby imparting an axial reciprocating movement toy the spindle 48 and the gear G mounted thereon.

A'I'he key |98 (Fig. 3) which is secured to they,

quill' 5I by the screws |9| and thedowel |92 serves to transmit the oscillatory motion of .the-

carrier 52 to the quill 5| andspindle 48 as the spindle rotates and the quill moves axially. y The recess |94 in the carrier in which the key |98 engages is longer than the key to permit free axial movement of the quill in the carrier while maintaining the oscillating driving engagement between the two.

Coil-springs |95 are provided to take up back- "lashin the screwl |18 and yto urge the quill A5| continuously rearwardly in' the carrier 52. 'I'hese springs, which are provided at angularly spaced intervals around the carrier, are mounted in aligned openings in the quill and carrier and bear at one .end against the spacermember |88 and at their opposite ends against the carrier,

Thecontact-member |84 (Figs. 5, 6, and '7) is held against one end of the bar |62 and the roller |68 is held in contact with` the periphery of the cam |58 by action of the spring-pressed plunger |96V (Fig-5). This plunger is housed in a bore in the Vguard |18. It engages a roller |91 that is secured by a stud |98 to the arm |65. A'c'oilspring |99 housed within a bore of the plunger |96 actuates the plunger.

In 'addition to the cams I32fand |58, there are a pair of cams 288 and 28| carried by the cam shaft 99. The cam 28 |4 is keyed to the cam shaft by the same keyi'wh-ich serves to secure the disc |3| to the cam shaft (Fig. 7) and the cam 288 is pinned to the cam 28I`. The disc |3| and the 1 cams 28| and 288 areheld against axial movement on theshaft by the nut 283 which threads onto the shaft. The cam 288 operates' a doublethrow switch which controls thev direction of rotation of'the gears being burnished', lapped or tested and the cam 28| controlsasingle throw switch that eiects the stopping of the machine at the end of the burnishing, lapping or testing .operation The double throw switch is shown in Fig. 17 and the single throw switch in Fig 18.

'I'he double throw switch comprises a body portion 285 and a pair of blade-arms 286 and 281 that are pivotally mounted at 288 on the body portion 285. The body portion 285 is itselir pivotally mnunted upon apin 284 in a 'switch-housing 289 which is suitably mounted on the bracket |39. There is a bar 2|6 mounted on the bladearm 286 and this arm carries a pairv oi' contact points 2|8 and 2H (Figs. 17'and 7). There is a bar 2|8 mounted on the blade-arm 281 and this bar carries a pair of contact points 2|2 and 2|3. A plunger 2|4 is slidably mounted in the body lportion 285 'of the switch. A coil-spring 2|5, which is interposed between the plunger 2|4 and the blade-arm 286, serves to urge the plunger 2 I4 downwardly and outwardly ofthe body portion 285 and also serves to urge the contact points 2|8 and 2H towards contacting engagement with a pair of terminals 2| 1. A coil-spring 2|9 which is interposed between the body portion 285 of the switch and the .blade arm 281 serves to urge the contact points 2|2 and ZIB into contact engagement with the terminals 228.

The body portion 285 of the switch is urged in one direction about,` its pivot 284 by a springpressed plunger 222 which is pivotally connected ,at 223 to the body portion'285 of the switch. This plunger is housed and slides in an opening 228 in the end plate 225 which is secured` to the bracket |39. The coil-spring 228 which surrounds the reduced stem portion of the plunger 222 and is housed in the opening 225 serves to actuate the plunger.

The double blade switch is tripped by la. spring pressed plunger 238 which is mounted to slide in an opening 232 in the end plate 225. A coil spring 233 is housed in this opening 232 and surrounds the stem of the plunger 238. This spring is interposed between a shoulder formed on the plunger and a guide-plate 235 which is secured in any suitable manner to the end plate 225.

There is a teat 238 formed on the projecting portionmf the plunger 238 at one side thereof.

The tip of the plunger 2| 4 is beveled off and the 233 forces the plunger outwardly butbecause of the engagement of the teat 238 with the plunger 2|8, this outward movement of the plunger 238 rocks the body portion 285 of the switch about the causing the blade arm 286 to break contact with the terminals 2|'1 andthe 'blade-arm 281 to make contact with the terminals 228.

4The terminals 2|1, as will hereinafter appear, are in the circuit of the main-drive motor 48, which drives the gears being burnished, lapped or tested, when the gears are rotating .in the lforward direction and the terminals 228 are in the circuit of the motor when the gears are being driven in the reverse direction.

After plunger 238 has rocked the switch 285 to break contact with the terminals 2|1 and make l -'contact with terminals 228, the plunger continues to move outwardly under 'actuation of the spring 233 .until the`teat 236 rides clearl of the plunger 2|8. Then, of course theplunger 222 and spring 226 will rock the switch back in the opposite directionA to break contact at the terminals 228 and make contact again with the terminals 2W.

To insure that'the contact points 2|2 and 293 will make contact with" the terminals 220 long enough to insure starting of the drive motor in the reversed direction, the end of the plunger 288 is formed witha shoulder 248 andthe tip of the 75 50 pivot end 284 in a vcounter-clockwise direction,

lug or cam 266e is beveled Voii? as indicated at 242. As the cam' shaft 98 rotates, then, the cam rst engages the end of the plunger- 288 pushing the plunger far enough in to engage the teat 286 behind the plunger 21d. rotation of the cam shaft, the cam 280 rides clear of the end of the plunger and allows the plunger to move outwardly under actuation o"the spring 233 causing the switch to break contact with the terminals 2| 1 and make contact with the terminals 220 but when the cam 288 rides clear of the end of the plunger 238, it engages the shoulder 266 of the plunger and the )outward movement of the plunger under actuation of the spring 238 is halted. 'Ihe beveled portion 252 of the cam engages theA shoulder 250 of the plunger for a long enough interval to assure that the reverse drive is started. Then the bevel portion 252 of the cam 280 rides clear of the shoulder 2&8 of the plunger and the plunger completes its movement to the right under actuation of the spring 233, breaking contact at the terminals 228 and making contact' again at the terminals 2 i 1 in the manner already described.

The single blade switch which controls the stopping of the machine comprises a body portion 255 and a blade-arm 248 which is pivotally mounted atv 251 on the body portion 255. The body portion 255 is pivotally mounted upon a pin 248 in the switch box 268. The switch arm carries a bar. 258`which is provided with contact points 252 and 253 (Figs. 7 and 18) that are adapted to make contact with terminals 255 (Figs. 18 and 25). v When contact oi the points 252 and 258 vith the terminalsV 254 is broken, the machine s Ops.

There is a spring pressed plunger 256 slidably mounted in the body portion 245 ofthe switch. A coil spring 258 is interposed between the plunger 256 and blade-arm 246 and serves to urge the plunger downwardly and outwardly and the blade-arm upwardly into Aoperative position. A spring pressed plunger 268 is pivoted to the body portion 245 of the switchat 26|. This plunger is housed land slides in an opening 262 in the end plate 225 and is pressed' upwardly by the coil spring 263 which surrounds the stem on the plunger. i wardly to normally rock the body portion 245 olf th switch about its pivot 248 to hold the switch c ose The body portion 245 of the switch is rocked in a counter-clockwise direction 'to open the switch by operation of a spring pressed plunger 265. This plunger is housed in an opening in the end plate` 225 and slides therein. It is pressed outwardly by a. coil spring 266 which surrounds the stem ofthe plunger and is interposed between a shoulder on the plungerand a cap-plate 261 which is secured to the cover plate 225.

There is a teat 268' formed on one side of the plunger 265 near the outer end thereof. This teat has a beveled end. When the cam 20| engages the plunger 265 in the rotation of the cam shaft 98, the lplunger is forced inwardly against the resistance of the spring 266 and the teat 268 rides under the plunger 256 which has a beveled tip complementary to the beveledtip of the teat. When the cam 20| has rotated clear ofthe end voi the plunger, the spring 2 68 forces thel plunger outwardly again 'but at this time the teatf268 is engaged behind the plunger 256 and so the switch is rocked about its pivot 248 causing the contact points 252 'and 258 to be dis-engaged from the terminals 264. This opens the 'I'hen in the continued This spring presses the plunger upcircuit of the machine as will be described morel particularly hereinafter, and stops the machine. As the plunger 265 continues to move outwardly under actuation of the spring 266, the teat' 268 clears vthe plunger 256 and the spring pressed 5 plunger 260 operates again to close the switch.

A dash-pot is provided in conjunction with the .plunger 268 so as to prevent the switch being closed again before the circuit to the controllers of the machine has actually been broken. This 10 dash-potcomprises a plate 218 (Fig. 18) which is secured between a shoulder on the stem of the plunger and the nut 21|. 'I'he plate 210 slides in a chamber or recess 212 and has substantially air-tight engagement with the walls of this 15 chamber. There are holes 213 through'the plate. Above the plate there is a disc 215 slidably mounted on the stem of the plunger and. having'a llmited movement thereon. When the plunger 260 .moves downwardly on the opening of the switch, 20

air passes freely through the openings 213 in the plate 218 and the movement of the plunger is not restrictedbut when the plunger mores up.- wardly again to reclose the switch, the disc 216 rests on the top of the plate 218closing the open 25 ings 213 and air is entrapped between the plate 218 and the inner' end` wall of the chamber 212 and so the upward movement of the plunger is retarded preventing re-closing of the switch un til suicient time has elapsed Ifor the controller to function and actually stop the machine.

To prevent the lapping or burnishing compound irom being sprayed about and to protect the operator against injury during burnishing or lapping a guard is provided to enclose the gears 35 during the burnishing or lapping operations. This guard comprises a xed housing 280` (Figs.

1 and 13) and a door or closure 282 that is pivotally mounted on the housing 288. The xed i housing 280 is secured to the base 38 of the ma- 40 chinev in any suitable manner in position to enclose the gear and pinionbeing burnished or lapped as shownin Fig. 2. 'Ihe door 282 .permits of access to thegears, removal of the gears after theu burnishing or lapping operation has 45 been completed and chucking of gears for a new operation. The door 282 is pivotally mounted uponthe xed housing 288 by means of a pin orl bolt 283. Y A coil. spring 284, which surrounds this bolt, has 50 one end in engagement withthe door and the other end in vengagement with the xed housing and serves to hold the door in any position to which itis moved. A handle 285 is secured to the door at one sidethereof to permit easy manipula- 55 tion of the door. y l

'I'he lapping compound is pumped ontopthe gears by a pump shown in dotted lines in Fig. 1 which is driven by a motor 285'. The pump f forces the lapping compound through the line 60 281 (Fig. 13) and the pipes 288 and 28,8, which are secured in the housing 280 into an elbow A288 (Figsl 13 and 14). T he elbow '286 has one or more openings 292 in it through which the lapping compound may drop into a funnel-shaped c5 receptacle 288. This receptacle is secured by screws 284 to the door 282 and it has a flexible hose 295 connected to it and leading from it; The nozzleA 298 of this exible hose is held in abracket 1 291 that is vertically and horizontally adjustable 70 upona second bracket 298 which' is ho ntally adjustable uponv'aI supporting 'plate )2 9. The supporting plate 288 is clamped to ribs 388 formed on the door 282 by clamping-.gibs 882 and screws 388 andthe supporting'plate is horizontally yad- 75 minnie justable on the ribs 300 in a direction at right angles to the direction of adjustment of the bracket 298 on the supporting plate 209.

The bracket 2914 is secured to the bracket 208 in any position of its adjustment thereon by the bolt 304 which passes through the vertical slot 305 in the bracket 291 and the horizontal slot 306 in the bracket 298. The bracket 298 is secured to the supporting plate 239 in any position of its adjustment thereon by bolts 308 which pass through horizontal slots 309 in a projecting portion 3|0 of the supporting plate.

'I'he various adjustments described permit of directing the lapping compound, when the door 282 is closed, onto the gears being lapped at the most desirable point for the lapping process.

The portion of lapping compound pumped up by the pump and which does not flow out through the opening 202 flows on through the elbow 290 into a return pipe 3| 5 which carries the compound past the gears and allows it to drop into the bottom ofthe fixed guard 230 whence it is returned to the sump of the pump system by the return pipe? The pipe 280 is ordinarily being operated for a lapping or burnishing process without the' door 282 being closed, a double-throw limit switch 320 is mounted on the fixed housing 280. This switch is so mounted that the roller 32| carried by its switch arm 322 must be engaged by the flange of the door 282 to close the switch before the motors 40 and 60, which drive the gears and eilect the burnishing or lapping motions, respectively, can be started vas will be described more' in detail hereinafter.

For applying a load to the gears during testing, a standard hand-brake may be employed such as illustrated in the patent to Slade No. 1,796,484 above mentioned. It is manipulated by the lever 325 (Fig. 2). This brake will operate upon the brake-drum |84 (Fig. 3) but as the construction of the same forms no part of the present invening or lapping operation. An improved form of back-lash brake has been provided upon the pres-v ent machine and this will now be described. 330` (Figs. 9 and 10), denotes a housing or sump which is secured to the end or cover plate 332 of the hand brake mechanism (Fig. 3) by bolts 334 (Fig. 10). The end plate 332 is secured to the guard 335 of the hand brake mechanism by screws 336 which thread into lugs formed integral with this guard. The guard is secured to the spacermember by screws '338 which pass through lugs in the guard and thread into the spacermember. The cylinder 33| which houses the chuck-releasel iston 58 is secured to the housingn 330 by screws 333.y

A gear pump 340 of any usual or suitable cor.- struction is mounted upon a bracket 34| which is secured by screws 342 to the'housing 330 at one side thereof. The pump 340 is driven from the gear spindle 48 through a pulley 331 which is fastened to the spindle, a pulley 339 which is fastened to the motor shaft of the pump, and the belting 343 which connects the two pulleys.

Flexible hose 344 and 345 are connected to opposite sides of the pump. The hose 344 is connected by an elbow 346 with a duct 341 formed in one wall of the casing 330.' The duct 341 connects with a well 348 formed in the bottom of the casing 330 (Figs. 9 and 11). There are two parallel ducts 349 and 350 that lead downwardly from this well. The duct 349 communicates with a duct 35| which is normally closed by a relief valve 353. This relief valve is slidable in the duct 35| and in aligned openings formed in the bottom of the casing 330. It is normally held in closed position by a coll spring 354, the tension of which may be adjusted by the screw 355 whichvis operated by the hand wheel 3,55.

The valve 353 has openings 358 therein which permit liquid to flow from the ductl 35| into the sump 360 when the valve is forced open by pressure of oil flowing into the'duct 35i through the line 344 from `the exhaust side of the pump 340. When the line 344 is on exhaust, the duct 350 is closed by a ball check valve 33| that shuts off communication between the duct 350 and a duct 362 which leads into the sump. When the pump 340 is rotating in theoppeosite direction, however, and the line 344 is on suction, the valve 33| is open and oil is drawn from the sump 330 into the pump. y

The hose 345 connects with a duct 333 which is similar to the duct 341 and this duct connects with a well which is similar to the well 348 and from which there lead two ducts similar, respec- .Y tension of the relief valve associated. with the line 3451s designated at 335.

When the gear spindle 48 is rotating` in one direction the pump 340 is so driven that it sucks oil from the sump through the ball check valve 33|, ducts 350, wdl 348, duct 341, elbow 346 and piping 344 and it exhausts this oil through the piping 345 and duct 363 and `a relief valve corresponding to the relief valve 353 back to the sump. In thisv direction of rotation'` of the spindle, the speed of rotation of the pump and therefore of the spindle is determined by the adjustment of the-hand'wheel 365 and of the relief valve controlled thereby. .Hence any desired load may be applied to the spindle 43 when rotating in the described direction.

Whenthe gears and .spindle 48 are rotating fin the opposite direction, oil is sucked from the pump 360 through a ball check valve corresponding tothe ball check valve 33|, the vduct 333 and the line 345 and is 1exhausted from the pump through the line 344, duct 341, well 343, duct 353, relief valve 353 and the openings'338 inv that valve back to the sump. The rate of rotation of the pump and of .the spindle 48 is then determined byy the adjustment of the relief valve 353 through the hand vwheel 353.y By the mechanism Y described, then, any suitable lad can be applied to the spindle 48 and to the gears being bur-A rushed or lapped during rotation of the gears in either direction. Pressure gauges 313 and 313 are provided to permit determining the brake- .load in either direction accurately.

One of the features of the present machine is the incorporation in the means for adjusting the pinion head 3| of a. dial gauge to permit precise adjustment of this head so that the pinion P may be adjusted accurately into correct meshing relation with the gear G for lapping or testing. The pinion head 3| is adjustable by means of a screw shaft 310 (Fig. 12) that threads into a nut 31| which is secured to the pinion head. The shaft 310 has a. sliding key connection with a sleeve 312 to which the hand wheel 314 is secured. The pinion head is also movable by means of a piston 315 which is connected to a piston rod 315 and is slidable in a cylinder 395 that is secured in any suitable manner to the base of the machine. The piston rod 316 is connected to a yoke member 313 by a nut 311. This yoke member is connected through ball thrust bearings 319 and 380 and the nut 382 to the screw shaft 310.

The piston 315 may be operated by a rotary control valve and an inching valve such as described-in Patent No. 1,881,999. As these valves form no part of the present invention they will not be described here.

Secured in any suitable manner to the yoke member 318 is a plate 385. 'I'his plate has a hook 386 at one end. The hook is adapted to engagevl the short arm of a magnifying bell-crank lever 381 that is pivoted at 388 on a guard 389 which is secured to the base or frame 30 oi the machine. The long arm of the bell crank lever 381' engages at its tip with the contact point of a dial gauge 390 which may be of standard or any suitable construction and which is also mounted in the guard 389. A glasssight 392 is provided in the guard to permit the operator to readily read the dial gauge.

For precision lapping or testing, it is desirable i to havev the gears being lapped or tested meshed very accurately as to depth. This is done in the present machine by first finding precisely the bottoming position of the pinion in the gear, that is, the position in which the tops of the pinion teeth bottom in the tooth'spaces of the gear and by then backing the pinion outof bottoming position the predetermined distance required until the pinion will run with the gear in the desired depth-wise mesh relation.

To nd the bottoming position of theV pinion,v

the teeth of the gear are aligned with the tooth spaces of thpinion and the pinion head 3| is inched on to the limit of movement ofthe piston 315 in "its cylinder 395 to engage the teeth and tooth spaces of the pair in mesh. The piston in its movement carries the piston rod 316 and. yokemember 318 with it and the yoke member carries the screw shaft 310, sliding this shaft inthe sleeve 312. Just before the piston 315 has reached its limit position, theV hook 386 on the plate 385 will engage the short arm of the lever 331 and impart movement to the contact point of the gauge Y gauge.

pinion teeth actually' Aswitch 245,the line 425;

left. This slight movement will be reected through the magnifying lever 381 to the dial gauge and the operator will know immediately that he has reached bottoming position. The operator will then rotate the hand wheel 314 to back the pinion away from the' gear a pre-determined Vdistance to the point where the pinion and gear will run accurately together, ordinarily to the position where theyhave true pitch-line mesh. In this backing-away movement, the head 3| will be moved relative to the piston 315, for the shaft 310 will rotate in the nut 31|. The amount of the backing-away movement may be determined accurately by reading the micrometer dial 396. against a zero mark on the end plate 391 ofthe cylinder 395.

Having precisely determined the correct position of mesh of one pair of gears, the settings of the screw shaft so determined will do for any pair of identical meshing gears and thereafter any pair of identical gears may be brought into correct depthwise meshing relation simply by inching the piston 315 on to the limit of its movement in its cylinder. lIt is only necessary to make a new precision setting when a different ratio of gears is to be lapped or tested.

For lapping, as has been described, the gear and pinion are rotated together in mesh andsimultaneously the carrier 52 is oscillated to impart an eccentric motion to the gear and the quill is reciprocated to `impart a depthwise movement tothe gear. For testing, the gears are simply run together in mesh and the oscillating motion of the carrier and the reciprocating motion, of the quill are'omitted. One way in' which a combination lapping and testing machine may be wired to accomplish the purposes oi' the present invention is illustrated diagrammatically in Fig. 25. The lapping circuit will be described rst.

At some convenient point on the machine there are secured an electric start button 400 and an electric stop button 40| (Fig. 25). The start button is a normally open button and the stop button is a normally closed button. For lapping, the door 282 (Fig. 13) of the guard 280 must beclosed before the machine can be started so that the switch 320 is in the position shown in` Fig.. 25 with the bar 402 bridging the terminals 403 and 404. 'I'he axial position of the shaft 99 must also be such that thepam |32 (Fig. '1) is inv engagement with the roller |35 so as to be able to' impart the oscillating movement tol the carrier 52. In this position of the shaft, the switch |96 will occupy the position shown in Fig. 25 with the bar 405`bridging the terminals 401 and 408. The reversing switch' 205 will be in the position shown in the Figs. 17 and 25 with the bar 2|5 and the contact points carried thereby bridging the terminals 2|1. The stop switch 245 will be in the position shown in Figs. 18 and 25 with the bar 250 bridging the terminals 254.

-When the operator presses the starting button 400 a circuit is made 'from the main line L1 through the line 4|0, the terminals 403 and 404 andthe bar 402, theline 4|2, the line 4|3, the line 4|4, the terminals 4|5 and 4|5 and the start- 420, the line 42|, the line 422, the terminals 423 and 424 and the stop button 40|. the line 425,V

the terminals 254 and the bar 250 of the stop 428 and the bar 429 of the reverse controller for the terminals 421and the maindrlve motor 4I of the machine, the line 'I6 488, the terminals 431 and 482 and the bar 443 of the forward control] r for the motor 48, the line 435, the terminals 4 8 and 431 land bar 438 of a controller for the oscillating drive motor 68 (Fig.

'7), to the main line L2. This circuit energizes' the coil 428 to close a two-pole normallyr open relay 448.

As soon as the relay 448 is closed, a circuit is made which energizes thev forward and oscillating controllers. The circuit to the forward controller is from the main line L1 through the line \442, the terminals 443 and 444 and the bar 445 of therelay 448, the line 448, the-coil 441 of the forward controller, the line 448, the line 422, stop button 481 -and the lines previously described to the main line L2. The circuit to the oscillating controller is made from the main line L1 through the line 452, the terminals 453 and 454 and bar 455 of the relay 448, the line 456, coil 451 of the oscillating controller, and lineI 458 to the line 448 and. thence through the line 422 and stop button 481 to`the main line L2 inthe manner already described.

The energized coil 441 pulls the switch-blades 468461, and 462 closed so that they make con- .tact with the terminals 454, 455 and 465, respectively and close a circuit to the main drive motor '48 (Fig. 1.) .through the forward controller and the lines 468, 459, and 418. vThis starts the motor 48 driving the meshing pinion P andthe gear G in the forward direction. At the same time that the energized coil 441 closes the switch arms 468, 461 and 452 it also closes-.the switch arm 412.

The energized coil 451 closes the switch arms 415, 416, and 411 and also the switch arm 418 so that these arms make contact, respectively, with the terminals 488, 481, 482, and 483 of the oscillating controller. The closed. switch arms 415, 415,

and 411 make a circuit through the oscillating breaks the circuit to the coil 428. The relay 448 v is a normally open relay. Hence when the circuit to the coil 428 is broken, the relay 448 opens. This breaks the described circuit to the coils 441 and 451, but the circuit to these coils is now maintained through the switches 412 and 418, respec- .-tively, and so the motors 48 and 88 aire not stopped.

The circuit to the coil 44'1 is maintained from the line L1 through the line 418, terminals 484 and 484 and bar 482, line 41 I, terminals 488 and 481 and bar 486, line 412, line 498, line 491, terminals 492, switch arm 412, line 494, terminals 211 and bar 215 of switch 285, line 495, line 445, the coil 441, lines 448 and 422, through the stop but- "ton 481 and the already described connections to the mainline L2. The circuit to the coil 451 is maintained' from the main line L1 through the described connections with the lines 412 and 498, the line 491, terminal 483,*switch 418,fline 498, coill 451, lines' 458, 448 and 422 and stop button 481 through the already` described connections to the main line L2.

Thedescribed circuits to the main drive motor 48 and oscillating motor 68`are maintained until gaf the cam 288 (Figs. '7 and 18) trips the switch 285,

l breaking contact of the bar 215 with the terminals 211 and causing contact to be -made between the bar 218 and the terminals 228.

When contact of the bar 218 with the terminalsi 211I is broken, the coil 441 is de-energized; the switch arms 4158, 461, 482, and412 open and the main drive motor 48 stops. As soon as the con-l tact bar 218 makes contact,)however, with the terminals 228, the main drive motor is re-started' l 'but in therevers'e direction. Theclosing of the contact of the bar 218 with the terminals 228 causes a circuit to be made from the line L1 through the line 418, the terminals 483, and 484 and bar 482 of switch 328, the line 411, terminals 488 and 481 and bar 4116 of switch 185, line 41?@line 413,. line 588, terminals 228 and bar 218 of switch arm 281, lines 581 and 582, coil 583 of the reverse controller line 584, Vand lines 448 and 422 through Vthe stop button 481 and the previously described connections to the main line La. This energizes the coil 583 closing the switch blades 585, 585 and 581 and also the switch blade The switch blades 585, 5856, and 581 make contact with the terminals 518, 511, and 5 12, respectively, causing the man1/drive motor 4t to be driven in the reverse direction through the lines 514, 515, and 515.

As already describedf the nose of the cam 288 contacts with the shoulder 248 of the plunger 238 (Fig. 17) only long enough to i ure restarting of the drive motor 48 in the reverse direction. -Then the nose of the cam slips off of the shoulder of the plunger and` contact of the bar 218 of the switch 285 with the terminals 228 is again broken. The circuit to the coil 583 is maintained, however, from the line L1v through the line 418, switch' 328, line 411, switch |85, line 412, line 488, terminal 528, switch 588,'coil 583, lines 584, 448, and 422 and stop vbutton 481 and connections already described to the main line Le.

'I'he main drive motor 48 continues to drive the pinion P and gear G in the reverse direction until the cam 281 (Fig; 18) trips the switch 2.45. 'Ihen the circuit -to the coils 583 and 451 through the stop button 481 is broken and both motors 48 and 88 are stopped. This stops the machine with its operations completed in one revolution of the cam shaft 89. The stop switch 245 closes again automatically but its 1re-closing is retarded sufficiently by the dash-pot plate 218 to insure `breaking of the circuit to the coils 583 and 451 and opening of theswitch arms 588 'and 418. Hence, on the re-closing of the switch 245, the motors 48 and '88 are not restarted, nor can they be restarted until the start button 488 is againvpushed in and when the start buttorr488 is y again pushed in, the machine will go through its full cycle. v

In order to use the machine for testing gears, the camshaft 58 must be shifted amally by the lever 153 (Fig. '7) to disengege the cam 132 from the roller and bring the concentric disc 151 into engagement with this vroller for in the testing operation, the gear G and pinion P are run together in` ixed positions and neither an oscillating motion nor an axial mation or' the gear is desired. In testing, also, the door 282 of the guard 288 (Figs. 1 and 13) will beopen.

When the cam shaft 841s shifted to engage the roller with the disc 181", 'the arm of the switch 198 will be moved to cause the bar 485 of this switch to break contact with the terminals 481 and 488 and to cause the bar 525,0f this switch to make contact with the terminals

Images