US2099161A

US2099161A - Grinding machine

Info

Publication number: US2099161A
Application number: US38633A
Authority: US
Inventors: Leeuw Adolph L De
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1935-08-30
Filing date: 1935-08-30
Publication date: 1937-11-16
Anticipated expiration: 1954-11-16

Description

A. DE LEEUW 2,099,161

GRINDING` MACHINE Filed Aug. 30, 1955v y 3 Sheets-Sheet 1 Nov. 16, 1937.

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H GRINDING MACHINE Filed Aug. 3o, 1955 ssheets-sheet 3 24 UNL 0 c/r HDM PH L DE L EEL/'w Patentedv Nov.` 1.6,.*1'937 UNITED "STATES PATENT oEFlcE GRINDING MACHINE l Adolph'L. De Leeuw, Plainfield, N. J., assigner to Norton Company. W tion of Massachusetts applicaties august so, 193s, sensi so; sacas s claims. (ci. isi-105) '10 provide a steadyrest and mechanism associated therewith improving the operation of .a grinding machine in which the work is gripped by end J pressure of rotating devices, the pressure being located along the axis of cylindrical work pieces.

15 Another object of the invention is' to improve the machine disclosed in U. S. Letters Patent No. 2,059,895 dated November 3, 1936 to Charles H. Norton and Albert G. Belden (Serial No. 566,738). Another object-of the invention is ilrmly to sup- 20 port a work piece underall conditions of 'practical operation. Another object of the invention is to increase the production of a precision grinder. Another object of the invention is to improve the machine -of U. S. Letters Patent No,

25 1,779,779 to Charles H. Norton. -Other objects i will bein part obvious or .in part pointed out hereinafter. r

The invention accordingly consists in the features of construction, combinations of elements.

' 30 and arrangements of parts as'will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated inthe following claims.

. In the accompanying drawings, in which is 35 shown rone of various possible embodiments of the mechanical features of this invention,

Fig.l 1 is a transverse sectional view'through a grinding machine embodying the invention par- 40 ticularly illustrating the cross feed-for the grind# ing wheel and the' steadyrest feeding mechanism, Fig. 2 is an enlarged fragmentary sectional `view of a switch, the section being taken on the line 2-2 of Fig. 1, 45 Fig. 3 is a fragmentary elevation of a load and fire vdevice and clutch,

Fig. 4 is a sectional view taken on the line l-I of Fig. 3, y

5 dos Fig. 6 is an enlarged sectional view of of the transmission, the section being taken along Fig. 5 is a perspective view of an actuatinglng wheel, work piece and including theisteadyrest slides, I

Fig. 8 is an enlarged vertical sectional view of another` part of the transmission also of the steadyrest slides, the section being taken along 5 the line 8-8 of Fig. 1,

Fig, 9 is a vertical sectional view of part .of the tron mechanism, the section beingtaken along the line 9-9 of Fig. 6.

First referring to Fig. 1, I provide a machinev 1o L;

base 20 which should be massive venough to hold 'the various machine elements rigidly enough to obtain precision results but may be hollow and provide mechanism supporting compartments,

the shape thereof in a particular embodiment of this invention bell-'lg` clearly illustrated lin the drawings wherefor I shall not further describe the same in detail. Uprising from the base is a pair of heads 2l, one of which is shown inv Fig. 1 and both of which are indicated in section 20 in Fig. 7;- these heads as more particularly shown in Fig. 7 support bearings 22 for hollow spindles 23 supporting tapered spindles 24 having disk shaped heads 25; resilient means, not shown.

urges the spindles 23 towards each other in order 25.

to grip work pieces W, one embodiment of such means together with power` means for opening and closing the work holding orchuckingniechanism being disclosed in U. S; Letters Eat'ntNo.

1,779,779 to Charles I-I. Norton, to which reference may be had.l The machine thus provides a work holding mechanism to hold a work piece W by end contact and 'pressure in an axial direction, and one or both of the spindles 23 may be `driven to rotate the work piece W. I prefer to drive both spindles 23 in so much as thereby a superior drive is eifected, and the driving mechanism may be of the type shown in the aforesaid Nortonpatent, or it may be of any other suitable type. The tapered spindles 2l 40 are removable and a number of them may be provided for varioua sizes and shapes of work pieces to be operated upon.

Referring now to Fig. 1, Iprovide a grinding wheel mountedfupon a spindle 3| which may 45 be journaled and driven in any usual or desired manner, and in accordance with established practice I rotate the wheel 30 in the direction of I prefer to rotate the' work piece vv in the oppowe,

site vangular direction to that of the grinding wheel 30,v so that at the line of contact their surfaces are moving in the same direction, although at different velocities. I may cause the relative surface velocity between wheel and work piece to be highly eiiicient for a particular size Vof work piece and a particular grade of wheel by rotatingthe grinding wheel 30 at a somewhat higher speed than if the wheel and work piece rotated inthe same angular direction, all Within the limits of practical requirements, and by this arrangement of the drive the wheel tends to rotate the work so that there is less chance of slippage between the work and the disks 25.

I mount the spindle 3| in la spindle head 32 part of which is shown in Fig. 1, and which may be integral with or suitably attached to a cross slide 33. Referring now more particularly to Fig. 6, the cross slide 33 has plane and V-

vsurfaces

34 and 35 on its under sidewhich rest upon plane and V-surfaces in

ways

36 and 31 which are attached to the machine base 20 and mount the wheel head 32 and the grinding wheel 30 for movement transverse to the axis of the work piece W. As shown in Figs. 1. and 6 I provide a screw 40 which, in this embodiment of the invention, is the medium of transmittal of rall movements ofthe slide 33 on the

ways

36 and 31, both for feeding and adjustment.I The screw 40 is mounted in radial bearings 4| and 42 and it abuts

thrust members

43 and 44, the thrust member 43 being inserted in a bore provided by the slide 33, as shown in Fig. 1, and the thrust member 44 being adjustable in an internally screw threaded member 45'which is located in the bore in the slide 33 vand fastened thereto. The screw shaft40 has a reduced portion which extends through the thrust member 44 and is vfastened to a gear 41` which meshes with a gear f base20 which actuates the power transverse feed and the power feed for the' steadyrest, and may rotate the work piece if desired. The armature shaft 56 has fastened thereto a clutch e1ement'51`, there being a mating clutch element 58 keyed to a shaft 59 which is mounted in

bearing blocks

60 and 6| provided in the machine frame 20. The clutch element 58 is urged to the right in Fig. 6 by means of Va spring 62 backed up by a collar *63, and a yoke lever 64 pivoted at 65 in a bracket 66 will move the clutch member 58 out of engagement with the clutch member 51 to disconnect the drive when the yokelever 64 is moved by the core 61 of a solenoid 68, which core 61 is connected to the lever 64 by a link 69. `Fig. 6 shows the solenoid l68 energized and the clutch disconnected, but as soon as the solenoid 68 is deenergized thec spring 62 reconnects the clutch.

Referring now to Figs. 6 and 9,-the shaft 59 has fastened thereto a worm gear 10 which meshesv with a worm wheel 1| fastened to a shaft 12 mounted inbearings 13 and 14 provided in a gear casing .15 which is mounted inthe machine base 20. Secured to a shaft 12 are spur .gears 16 and 11 which constantly mesh with spur r limiting stops theregears 18 and 19. The gear 16 lis small and the gear 18 relatively large, while the proportions of the gears 11 and 19 are different, with the result" that the gear 18 is rotated at a slow speed while the gear 19 is rotated at a higher speed; gear 18 is fastened to a sleeve 80 mounted in ajournal 8| provided in the gear casing 15 while gear 19 is mounted on but not fastened to a shaft 82 journaled in a journal 83 provided in the gear casing 15 andalso in the sleeve 80. Shaft 82 has keyed thereto a double clutch element 84 having a groove for the reception of a shifting yoke 85; one end of the clutch member 84 may be brought into engagement with a clutch element 86 integral with the gear 19, while the other end of the clutch member 84 may be brought into engagement with a clutch element 81 integral with the sleeve 80, the clutch member 84 being slidable upon the shaft 82 for the purpose of conecting either the gear 18 or the gear 19 to the shaft 82 and thus driving the shaft 82 at eitherl a slow finishing feed rate or a fast cutting feed rate respectively.

Still referring to Fig. 9, fast upon the end of the shaft 82 is a bevel gear 90 meshing with a ubevel gear 9| fast on a shaft 92. Referring now to Fig. 6, the shaft 92 is connected by means of a clutch 93 with a shaft 94 which is journaled in

bearings

95, 96 in the machine frame. The purpose of the clutch 93 is to permit the gear box 15 to be removed as a unit and the shaft extends forwardly to a nut 91 for setting up or making 'adjustments of the machine.

Fixed upon the shaft 94 is a worm 98 which meshes with a worm wheel 99 which is mounted upon and drives a shaft |00. The shaft |00 is thus rotated at a reduced speed through a transmission train involving a pair of worm and worm wheel reduction units and at the selected rate of two feed rates, determined by the change gear mechanism described, that is to say at a rapid feed rate or at a slowor finishing cut feed rate. The shaft |00 is lconnected to feed transversely the slide 33 and it is also connected simultaneously to feed the steadyrest mechanism in timed relation thereto. In this particular embodiment of the invention, I have disclosed a two-rate feed mechanism and also a start and stop clutch in the transmission train but no reversing mechanism and the retrograde movement of the slide 33 and also the supports for the steadyrest is effected by' barrel or ltrack cams. Certain advantages inhere in the use of such barrel or track cams among them being simplicity of operation and flexibility of control. l

The drum |0| is maintained upon the shaft |00 by means of a couple of nuts |08 on a screw threaded portion of the shaft |00. .The shaft |00 is journaled in main journals ||0 and provided in the machine base, and in order that end play may be eliminated washers ||2 abut the journal and are backed up by a collar ||3 xed'to the shaft |00 by means of a taper pin ||4; the nuts |08, a washer ||5, the drum |0| and a pair of washers I I6 being used to eliminate end play in the other direction and to adjust and tighten the assembly.

The shaft |00 has a reduced portion ||1 upon which is fitted a bushing ||8 in the central hub ||8 of a cover |20 which may be secured by screws, not shown, to the base 20. Inside the cover andfastened by means of screws, not shown, to the drum |0| is an actuating dog drum |2| with a pair of T-slots |22 and |23 in which may be placed at any desired angular position dogs to actuate the control for the change gear mechanism to shift from fast to low feed.

Referring now to Fig. 6, the

slideway members

36 and 31 have respectively the opposite slidewaysurfaces and |25 of a dovetailed slideway which supports for movement, parallel to the slide 33, a slide |21. The slide |21 has secured to the top thereof a half nut |28 which engages the screw shaft 40. Slide |21 also has, as shown in Fig. 1, a stop stud |29 positioned to engage a stationary stop stud |30 located in the machine base 20, so that the forward position of the slide l21 is xed and predetermined and never varies..

According to the invention I may determine the nal size of the work piece by bringing the wheel slide to a fixed and predetermined position at the same time holding the work piece against the grinding wheel by surfaces which for the final size are located at a predetermined position. At the same time I may rotate the work by frictional or otherwise end contact, with pressure in an axial directiorifand by reason of such construction and mechanism, loading is a momentary matter. Tracing the grinding operation back-V wards, in order that chatter marks may be eliminated and adrive effectedwhichkeeps the rotating spindles coaxial with the work piece, I move the steadyrest awayl rom the axis of thework piece in the opposite irection and as th wheel slide moves backwards.v I prefer to provide two work piece supporting surfaces so that the work may be supported 'atfmor/e than two places, including the-line of grinding, and I compensate for the change of 'size of the work piece 'by moving the steadyrest at a greater rate than the grinding wheel feed slide, which rate is determined by the cosecant of the dihedral angle between the plane through the axis of the work pice and parallel to the advance of the steadyrest and the plane of tangency of either rest with the work piece, such ldihedral angles being preferably the same as otherwise one steadyrest surface wouldleave the work piece or cause undue pressure between the parts at some stage of the operation. Thus as the angle defined becomes smaller the rate of feed of the steadyrest mechanism divided by the rate of 'feed of the feed slide becomes` larger, until with the steadyrest surfaces tangent to the top and bottom of the work piece this ratio is infinity because if such a steadyrest should hold the work piece at the start of an operation, it could never hold it after it had been ground to any extent. By making the dihedral angle defined for the two steadyrest surfaces the same, a single work piece cooperates with the relative rotation of Wheel and work `piece hereinbefore defined and to a large extent reduces pressure and resistance and increases the effectiveness of the threepoint support. v

Referring now to Fig. 8, there is provided a slideway having dovetailed ways |56 to receive the slide |60 and having further dovetailed Ways |18 for the support of the steadyrest member |19which, as shown in Fig. 7, comprises an integral rectangular slide portion integral with apair ofrest arms |80, the part being Y-shaped in cross section as shown in Fig. 1.

Referring now to Fig. '1, the slide |15 `is ordinarily in advanced position, that is to say in the direction of the work piece with respect to the slide |65, being held in that position by springs |8| around bolts |82 which extend between standards y| 83 and |84 provided respectively on the slide |65 and the slide |15. Nuts |85 limit the forward position of the slide |15 with respect to the slide |65. The slide |11 is, during the grinding operation retracted with relation to the slide |15, being held merely temporarily in the position shown in Fig. '1 by a spring |86 extending between the standard |84 and a standard |81 provided on the slide |11, and there being a lbolt |88 and nuts |88 to limit the advanced position ofthe slide |11 and nuts |80 to provide a solid backing for slide |11. Thus these three slides during certain parts of the operation function as one, and the operator may grasp a knob 8| to pull the slide |11 away from the work piece 'when loading. Likewise the springs |8| provide for relative movement between the slides |65 and |15 at the ilrst part of the grinding operation to facilitate the grinding of out-of-round Work pieces, but prior to the finishing of the grinding` operation I* may positively move the slide |15 to its advanced position with respect to the slide |65 by a mechanism which will presently be described. It maybe noted here that for certain operations and certain classes of work one of these slides may be dispensed with, and for cer.- tain operations I .prefer an altogether rigid mechanism, and I contemplate that the grinding wheel and the steadyrest shoes |82 shall hold the work piece coaxial with the driving heads 25 especially for the final and nishing' cuts.

Considering n ow the grinding of a work piece W, and assuming that the cam drums |04 and |56 are in such angular position as to withdraw both slides, the operator grabs the handle |9|,

Iand withdraws the slide |11 and thus the steadyrest arms |80, while at the same time setting in operation mechanism disclosed in the patent to Norton referred to, to retract the work gripping disks 25. He may then insert a work piece W and cause the disks 25 to\approach to grip the but the rest shoes |82 may be allowed to engage to the shoe 203 is an insulating plate 204 to which is secured a metal plate 205 that is contacted by spring pressed

contacts

206 and 201 in a switch box 208.w When the arm 202 is moved clockwise, Fig. 1, the plate 205 leaves the'contact 201, and thus breaks a circuit between

lines

209 and 2|0 which, together with line 2|| energize the solenoid 68. Then when the operator pushes the lever 200 away from him, the solenoid 68 is deenergized,' permitting the spring 62to cause engagement of the clutch member 58 with the.

clutch member 51 thus actuating the feeding mechanism. The drums andn |50 are thereupon rotated causing the slides ||6 and 33 to approach each other at the relative rates hereinbefore specied, and at this time the clutch 84 is in the vposition shown in Fig. 9 to cause a rapid movement. The rate is constant, however, only so far as the angular velocity of the barrel cams |04 and |56 are concerned, and any desired rate or change of rate may be incorporated in the shape of the cams; I prefer to make the camtracks and |51 similar in pitch at a definite ratio to each other in order that the work piece W may bev centered upon a threepoint supportI comprising .the steadyrest shoes |82 and the grinding wheel 30 at all times during the grinding operation.

In Fig. 1 I have shown the steadyrest shoes |82 in contact with the work W prior to engagement of the wheel with the work piece. Until the grinding wheel'engages the work piece, however, the shoes have no eifect upon the work piece, and in fact the principal reason for providing aseparate slide |11 and the spring |86 vis to facili- .tate centering the work between the

disks

25, 25,

for the operator may place the work piece W tangent to the shoes |82 with the slide |11 forward in order to ilnd the correct position for the work piece; vthe spring |86 is a very light spring and in certain cases the nuts |88 may be tightened up to hold the standard |81 between them and the nuts |90.4

The slow feed comprising the gears 16 and 18 is provided to give the machine greater capabilities within the limits of a reasonable sizledl cam drum and at a predetermined but adjustable position a dog 2|2 located in the T-slot |23 engages a detent 2|3 which as shown in both Figs. 6 and 1 causes the shifting of a rod 2|4 toward the front of the machine, which rod is slidable in a bearing bracket 2 5 nxed to the machine base 20. 'I'his may happen at or after the commencement of grinding. Referring now to Fig. 1, a link 2|6 connects the rod 2|4 to an arm 2|1 which is fastened to a shaft 2I8 mounted in a stationary bracket 2|8, which shaft 2|8 passes through and controls the yoke 85 in the gear change box 15 in order to shift the clutch 84. Accordinglyforward movement of the shaft 2|4 shifts the clutch 84 to cause the transmission to act through the fine or slow feed gearing. The grinding operation proceeds until such a time as cam slots |05 and |51 have advanced the wheel and the steadyrest tothe limit of travel, whereupon the cam slots reverse the direction of movement and separate these parts. At the reversal of movement, the grinding is completed, and in order to save time the pitch of the cam slots may be high for the movement of separation and the rapid feed may be engaged. I provide-a dog 220 to engage thev detent 2|3 and move the rod 2| 4 rearwardly to bring the parts back to initial position rapidly in order to save time, and in the preferred embodiment of the invention the cam drums rotate 360 for each grinding operation and then come to a stop by reason of the engagement of a. dog 22| on the `drum |6| with a spring pressed detent 222 on the end of a rod 223 which is mounted in an yarrn` 224 integral with arm 202.

As shown in Figs. 1 and 8, a spring 225 around the rod 223 acting against a head 226 constitutes resilient means'for maintaining the detent in its upper position, there being a screw 221 and a- .a,oaa,1e1. Y.

.- for readily adjusting the position 1oi? anylsteady tions. -The machine may'be started in spite of device which is especialLv illustrated in Figs. 3

the engagement of dog 22| with detent 222, because thespring 225 will compress allowing the switch controlling the solenoid 68 to be opened;

the machine comes to a stop with the partsl in the initial position when thev drums have ytraveled 360 and the arm '202 has been moved again to`J reenergize the solenoid 68.

In order to avoid possible failure of the mechanlsm-by reason of the clutch 84 hangingin mid or neutral position, I provideY a load and -ilre and 4, and which comprises a pair of spaced arms 225 vconnected to the yoke 85 having adjustment may be formed to throw the dagger 231 from one notch partiallyinto the other but without disengaging the clutch by so doing, owing to the lost motion, whereupon the spring will carry the dagger and shaft 2|8 the-rest of the .distance -to shift the clutch member from oney side to the other.

For, the grinding of many work pieces the mech anism and mode of operation which has been described may besuflicient and give the best results, but in certain cases I may use the springs |8| to permit the steadyrest-to back away especially at the start'of a grinding operation. providing mechanism to lock the slides |55- and |15 in definite spaced position automatically' before the finish ofthe grinding operation.I It may be understood, however, that in many respects the provision of simple spring means will effect this result and in certain cases I prefer to use a steadyrest which is always maintained in geometrically correct position with a ilrm pressure.

Considering, however, the additional mechanism which may be used upon occasion, (at other times the slide being pinned orrigldlyfastened to the slide |65 and the parts particularly to be now described4 being altogether removed from the machine) there is a wide hole through the slide |60 permitting a screw rod 240 which passes through a boss 24| in the center of the slide |65 to extend downwardly through the slide |60. A nut 242 is mounted onthe rod 240 and this may be locked in position by a check nut 242, which holds the rod 245 from rising above a certain position. To the lower end of the rod 240 is fastened an arm 244 which has a portion 245 in position to be engaged by

dogs

246 and 241 ad- VJustably secured in the T-slot `|62 of the drum |5|`. The`former dog moves the arm I245 to lock the slide |15 to 'slide |65 in advanced xed position, while thelatter unlocks the parts. This is effected by means of a' wedge member -25|) having, as shown in Fig. 1, an inclined surface 25| on its right hand side adapted to engage a stationary wedge 252 4secured to or integralwithv 255 may be provided to lift the wedge nut 250 i when the parts are unlocked.

Considering now Fig. 7, the steadyrest member |18 may be readily removed from its supporting slide |11 by removing bolts 250 whichiit in slots 25| in thesteadyrest member |19 and screw into,y

holes inthe slide |11. This constitutes means rest with respect to its supporting slide |11./f`

Comparing-now Figs. 6 and 8, an exampleof the timing of the machine is shown.l It should be remembered that the change of feed rate may be inaugurated either at the commencement of grinding or at some later time; in the first inthe parts together into grinding position and in the second instance fast feeding performs what may be called the rough grinding. These variations 4are all within the contemplation of the invention, being made by mere adjustments of the machine. By way of-example only, therefore, turning to the right hand side of Eig. 8 it will be seen that the dog 2|2, which is moving in this view counterclockwise, will move 120 lbefore it contacts the detent 2|`3 at which point the slow feed is inaugurated. For seventy-five more degrees of angular movement the grinding.

takes place at a slow feed and at the end thereof i there is practically a dwell in the cams and as the cams commence to withdraw the' slides 'the second dog 220 causes the mechanism to feed rapidly again. Compare Fig. 6 with Fig. 8 remembering that direction of rotation is opposite in these two figures.

' stance fast feeding is for the purpose of bringing Referring now 'to the left hand side of Fig. s.

165 subsequent .to the start of an operation the slides |55 and |15 are locked together by means of the dog 246, while the unlocking operation takes place 45 thereafter which is 210 vfrom the start of the operation or 15 after the reversal in 'direction It must be emphasized, however, that this is only-one of a`. great many ways of setting `up the machine and is given for a clearer understanding of the mechanism. Ultimately after 360 of rotation dog 22| operates the detent 222 whereupon the machine stops and is ready for another cycle of grinding.

In the of successive workpieces the grinding wheel will ultimately wear, but this can be advanced with respect tothe slide |21 by means of the hand wheel 53, and a dressing operation may be performed to bring the vertical planeo! tangency with the wheel to afixed position s o that rigid control over the ultimate size of work pieces may be readily achieved.

- It will thus be seen that there has been provided by this invention an apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as grinding wheel, a slide for such steadyrest, power means to advance and retract the rst named slide, power means to advance and retract the second named slide, means synchronizing movement of said slides, and automatic means to' cause said slides to stop at apredetermined position. 2.1m a grinding machine, a grinding wheel, a

'steadyrest, a. slide to relatively advance the steadyrest relatively .to theaxis of a work piece,

feeding means `to move said slide, and means automatically to change the rate of feed.

3. In a grinding-machine, agrinding wheel, 'a rotatable member to rotate awork'piece, means to relatively move the wheeland member, a steadyrest having a. steadyrest suri'ace, -means to relatively move the steadyrest and lmein-,- ber, a plane of tangency at thecontact lsuriace makingr an acute angle to the direction of Emotion last specified, and `means to bring the steadyrest surface to a position a given tact with the work piece, of means to move the grinding wheel, means to move the steady rest elements, the grinding wheel and the steady rest surfaces being al1 of them tangent to a given circle and the lines oi tangency for each being on the circle more than 180 remote from one of the others in each angular direction, the means to advance the grinding wheel and the means to advance the steady rest elements being synchronized so that as grinding proceeds the three elements are .maintained tangent to smaller and smaller circles all of which are concentric to the given circle, whereby to achieve accuracy in the' grinding of a work piece located concentric withl the given circle.

5. In a grinding machine as claimed in claim 4 the combination with the 'parts and features therein specified of driving means for the work piece constituting a pair of pressure plates urged against it in oposite directions along the axis' of the given circle. l

6. In a grinding machine as claimed in claim 4 the combination with the parts and features therein specified of a rigid connection between th'e two steady rest elements.

ADoLPH L. DE LEEUW.