US1684486A - Grinding machine - Google Patents

Description

Sept. 18, 1928. 1,684,486

W. J. GUILD ET AL GRINDING MACHINE Original Filed 1926 8 Sheets-Sheet 1 r1 yarz Sept. 18, 1928. L684A86 W. J. GUILD ET AL GRINDING MACHINE Original Filed 7. 1926 8 Sheets-Shee 2 fizoevm 717564 0 1]. GucCd lea/1's 6T Ken 071 Www Sept. 18, 1928.

W. J. GUILD ET AL GRINDING MACHINE original F'il d Jan. '7, 19 26 8 Sheets-Sheet 3 15806752??? 73 50220 J Guo6d legals 6. Magyar;

yZZw/Z/ Sejat. 18, 1928. 1,684,486

W. J. GUILD ET AL GRINDING MACHINE Original Filed Jan. 7, 1926 8 Sheets-Shee 4 .Sept. 18, 1928.

W. J. GUILD ET AL GRINDING MACHINE Original Filed 7, 1926 8 Sheets-Sheet 5 wM w% RQ QQN .Zr'zwrzzra: 7 Web I 6201a? [eh 1%? A4922 arz (m /WM Sept. 18, 1928.

W. J. GUILD ET AL GRINDING MACHINE Original Filed 7, 1926 8 Sheets-Sheet 6 n In I gal lFzwnfars; Wilda 7. 'azld Laws 6. Kenya/z Sept. 18, 1928. 1,684,486

w. J. GUILD ET AL GRINDING MACHINE Original Fi'ledJanfl, 1926 8 Sheets-Sheet v lei/5 c1 Ian 072 Sept. 18, 1928.

w. J. GUILD ET AL GRINDING MACHINE Original Filed 7, 1926 8 Sheets-Sheet a I Jrzaavzf'orsx W0 0 .Z' fiat/d Zeb 11s 63 Zen 0?? Patented Sept. 18, 1928.

UNITED STATES PATENT OFFICE.

WALDO-T. GUILD, OF WORCESTER, MASSACHUSETTS, AND LEWIS CLIFFORD KENYON,

OF NEW YORK, Y1, ASSIGNORS TO THE HEALD MACHINE COMPANY, OF WORCES- TER, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

GRINDING MACHINE.

Application filed Ianuary'7, 1926, SerialNo. 79,8 49. Renewed April 8, 1928. i

The invention relates to grinding machines,

ment upon and an addition to the prlor in-' vention shown and claimed in the copending application of Kempton and Gallimore, Serial No. 6,689, filed February 4, 1925, and also to the prior invention shown and claimed in the copending application of Heald, Guild, Burns and Garno, Serial No. 4,466, filed January 24, 1925. In particular, the invention provides means for automatically dressing the rapidly r0- tating grinding wheel a plurality of times during the grinding of a workpiece, said dressing being initiated by devices responsive to the movement of a gauging or calipering device that is maintained in operative relation to the surface being ground. Between the said dressing operations the grindi-ng wheel is brought into'contact with the work, to make at the least a. single cutting traverse on the surface thereof. .By thus interrupting the grinding operation two or more times to dress and true the grinding wheel, the latter is kept sharp and free cutting, in consequence of which the relative advance or cross feed between the wheel and the workpiece occurs without producing any spring in the grinding wheel spindle, once the first dressing operation has occurred.

Other and further objects of the invention will appear from the following detailed description, taken in connection with the accompanying drawings, in which- Fig. 1 is a front elevation of a grinding machine built in accordance with the invention, showing the carriage in the work removing position.

Fig. 2 is a plan view of the work calipering mechanism.

Fig. 3 is a front elevation showing the switch operating mechanism on an enlarged scale.

' Fig. 4 is a section on the line 44 of Fig.3.

Fig. 5 is a sectional view on theline 55 of Fig. 4, showing the switch, together with a wiring diagram of the machine.

Figs. 6, 7 8 and 9 are views on a reduced rear of the machine, showing the dresser movscale of the switch mechanism of Fig. 3, showing the parts indifferent positions.

Fig. 10 is a plan view of the machine, il owilng the carriage fully withdrawn, as in Fig. 11' is a front elevation, showing the parts in'the normal grinding position.

Fig. 12 is a fragmentary-view from the ing mechanism.

Fig. 13 is a sectional view on the line 13-13 of Fig. 12.

Like reference characters refer to like parts throughout the drawings.

Referring first to Fig.1, the machine provides the usual reciprocatory table or-carriage 1 which is ordinarily provided in any internal grinding machine. In such a machine, either the grinding wheel or the work to be ground may be carried on the table 1, the reciprocation of the latter being utilized in either case to produce a relative traversing movement between the grinding wheel andthe'work. As here shown, the table 1 supports and carriesa wheel head 2, while the work whichis to be operated upon is held in a work head 3, the latter being carried bya bridge 4, which spans the slideways provided by the machine frame for the back and forth movement of the table 1.-

This back and forth movement of the table 1 to cause therotating grinding wheel-5 to make the required interior traverse of the rotating workpiece 6 may be imparted in any well known manner, as for instance, by the use of the fluid pressure controlling and reversing mechanism which forms the subject matter of'the copending application of Heald and Guild,Serial No. 629,882, filed April 4, 1923, now Patent No. 1,582,468, granted April 27, 1926. Suchmechanism, or its equivalent, forms no part of the present invention, and a detailed descriptionthereof is therefore unnecessary; it is sufiicient to note for the urposes of the present application, that the (Friving means employed for the reciprocation of the table -1, be it hydraulic drive, or gear drive, or any other type, procures the reversal of said table at each end of the latters normal working stroke by the use of spaced ad- 100 justable dogs 7 and 8, carried by theitable 1 and adapted to alternately engage and move a reversing member 9; the latter, during'the at high speed in any suitable manner, as for instance, by a belt drive for the wheel spindle 10, the latter for this purpose carrying a pulley 10. The workpiece'6 is also rotated, but

at a slower speed, this rotation being imparted in anysuitable manner as by a belt drive, not shown, from acountershaft.

Referring to Figs. 1, and 10, the machine also embodi'esthe usual instrumentalities for both manual and automatic cross feed between work and wheel, here shown as embodied in a screw shaft 11 for feeding the wheel head 2 transversely of the table-,1. Said screw shaft 11 may be operated, if desired, by. the usual hand wheel 11*. The automatic operation of said screw shaft 11 is effected in the usual manner, at each reciprocation of the table 1, by a fixed dog or stop.

12 which is engaged by a roller 13 on a pivoted arm 14; the movements of said arm are transmitted through a pawl 14 and ratchet wheel 14 and reduction gearing, not shown, to the screw shaft 11, thereby to obtain the automatic cross feed of the grinding .wheel 5 at each reciprocation of the table.

As shown in Fig. 2, a-member 15 has at one end a work calipering point 16 adapted, during the operation of 'grinding a workpiece, to bear against the internal surface which is being ground, and to maintain its contact with said surface. as the hole in the workpiece is gradually enlarged by the grinding action of the wheel; The member 15 is to all intents and purposes a lever said member, for the movement requiredo it to maintain the point 16, in constant contact with the interior of the gradually enlarging hole in the wor iece, being ported by a pair of flexi le' U-shapedflat springs 17 and 18, which springs cross each other, and are attached to two adjacent sides of a rectangular block ortion 19 of member 15. At their other en s the crossed springs 17 and 18 are attached to two inner surfaces 20 and {21 of the box 22, these surfaces 20 and 21 being at right angles to each other, and the box 22 providing an opening 23 of sufiicient size to permit the inward extension 15', of member 15, to move fieel about the pivotal axis which is afforded by the intersection of the planes of the U-shaped springs 17 and 18. This pivotal movement is accom; -plished by the flexing of these two springs,

and .takes place in the entire absence of lost end adapted to move across the grad'uations of a suitable scale 26. Lost motion may be eliminated at bearing 25 by a. spring 25. The connection between extension 15 and indicator lever 24 is made by a spring 27,- which draws the parts together and maintains the lever 24 in contact withthe end of a screw 28, said screw being adjustably threaded in extension 15 and passing at its head end through a suitably enlarged slot or hole 29 in boxt22, so as to permit adjustment from the exterior of said box. Fig. 2, re resenting an illustrative embodiment of this mechanism, shows the end of screw 28in a cutout portion made in lever 24, but it must be understood that said screw and lever are entirely unconnected,

and merely bear against each other by reason of the pressure of sprin 27. By turning the screw 28, the indicator lever 24 can be made to assume any desired position relative to the member 15, and said screw 28 is maintained in any given setting, and displacement thereof prevented by any suitable friction device, such as a s ring 30. With the arrangement above escribed, a very slight movement of the calipering point 16 is multi manipulated, being transmitted through the above described connections to the indicator lever 24.

The multiplied movement of the latter is made use of at predetermined points in the grinding of each-workpiece to set in operation the wheel dressing instrumentalities a plurality of times, and finally toibring about a cessation of the grinding and. cause the grinding wheel 5 to withdraw from the workpiece 6. To this end the lever 24 carries three or more contacts, ,this embodiment shown as three,'namel a; -contact 32 to bring about the first stage ressing, a contact 33 to cause the dressing instrumentalities to again come into operation, which we call the second stage dressing, anda contact 34 to brin about the cessation ofv grinding. In the pat s of these three contacts 32 33 and 34, the box 22 provides suitable insulated stationary terminal contacts 35, 36 and 37, respectively. In the movement of lever 24, the points 32 and come first into con then points 33 and 36, and finally points 34 and 37, and in order to permit this succession of contacts, points 32 and33arecarriedattheendofflatsprings38 and 39 respectively, both attached to the lever 24, so that by the yielding of these springs, the subsequent movement of said lever to' bring the point 34 into contact with point 3? can take place with a negligible resistance.

As clearly described in the application of Heald, Guild, Burns and Garno, the box 22 is mounted for swinging movement about .a pivot 40, and when the final withdrawal movement of table 1 takes place, withdrawing the wheel 5 from the workpiece" 6, a cam member 41 strikes a roller 41' on an arm 41 attached to the box 22 andswings the box 22, carrying the calipering lever 15, away from the workpiece. A spring 42, see Fig. 1, automatically returns the box 22 to its operative position as the wheel 5 enters a subsequent workpiece 6, and means is provided to allow the calipering point 16, generally a diamond, to enter the new workpiece without striking the mouth of the latter and chipping the point 16. It is not believed'necessary to describe these mechanisms and the various adjustments in detail, as they have nothing to do with the present invention, and enough of the calipering mechanism has been described to illustrate said present invention. i

Referring now to Fig. 5, the instrumentali ties of the present invention, whereby a plurality of wheel dressing operations may be automatically inaugurated; will'now be described. The character G indicates a generator of any desired sort, preferably suppl ing direct current. One terminal of the said I generator is grounded and the other terminal is connected by means of a branching lead 43 to the coils of two elcctroma ets 44 and 45. The other end of the coil 0 eIect-romag-F net 44is connected by a lead 46 toastat-iom my contact plate 47 of'a switch, generally,

designated by the numeral 48. The other end of: the coil of electromagnet isco'nnected by a lead 49 to the stationary terminal 37. The stationary terminals 35 and 36 are connected respectively by leads 50 and'51 to stationary plates 52 and 53, also part of said The magnet 44 controls, by mechani'sm to be described, the dressing operation and whenever it is energized, the wheel 5 is dressed by causing it to pass by a diamond 54, see

' Fig. 1. The magnet 45, when energized,

brings-about a cessation of the grinding, and prepares the machine for the intrnductlon of a new workpiece. v

Referring particularly to Figs. 3, 4 and 5, the switch 48 provides a movable bridge con tact member 55, the position of which, as hereinafter pointed out in connection with said figures and also Figs. 6, 7 8, and 9, determines which of several electric circuits will be energized. Said bridge contact member 55 is carried by an insulating collar 56. The latter is fastened to a melnber 57 which in turn is fastened to a central shaft 58 of the switch. Shaft 58 supports the movable parts, of the switch, and is itself journalled in a sleeve casting 59 of the switch housing. The member 57 provides a ratchet segment 57*, by means of which the bridge contact 55 is moved into difierent positions. The shaft 58 likewise serves as a pivot for a lever 60, the latter carrying a spring pressed pawl 61. Attached to the lever 60 is a connector 62, and when this connector is raised? the pawl 61 actuates the ratchet segment 57 and thus turns the shaft 58 and associated parts. A hold pawl 63, engaging the'ratchet segment 57", normally prevents' retrograde movement of the shaft 58, said pawl 63 being carried by a lever 64 pivoted at 65. A connector 66 is attached to the other end of this lever 64, and when it is moved downwardly, the pawl 63 is raised, whereupon a coil ring 67, which has been wound up by movement of the shaft 58, acts to return the parts to original position, as shown in Fig. 3. As the outer peripheral radius of'the member 5'1 is greater than the radial distance of the.

segment 57, the parts will be stopped as shown in Fig. 9, notwithstanding pawl 63 is raised. A spring 68 tends to hold the pawl 63 in engagement with the ratchet segment 57. Before proceeding with a description of the operation of these parts, the machinc motions inaugurated by energizationof the magnets 44 and 45, willbe described.

Energization of the electromagnet 44 causes attraction of an armature member 69,- and the consequent elevation of its attached lever'armr70,-these parts being pivoted at 71 on the frontof the machine. See Fig. 1. Such movement of the lever arm 70, responsive to the engagement .'of contacts 32 and 35, or 33 and 36, is made use of to automatically interrupt the grinding operation on' the workpiece 6 for the dressing and truing of v the grinding wheel 5. This involves the withdrawal of the grinding wheel 5 from the workpiece, and the-disposal, in the temporarily amplified path of movement of .said wheel, of the dressing -device or diamond 54; these two operations areefie'cted through the mediumof the lever arm 70 in the following manner. 1 As fully described in the copending application of Heald and Guild, Serial N 0. 25,900, filed April 25, 1925, the dressing device 54 ay be moved into operative position through made available for the movement of dressin I device 5 1 into'ope'rative position forms o itself, no part of the present invention, being fully described and claimed in the aforesaid 75 rising from the stationary frame of the grinding ivheel 5.

machine. When the lever arm 7 O is moved, a downward extension 76 thereof communicates said movement to a valve 77, Fig. 1, thus ,making the pressure fluid active,

through piping 110 (see Figs. Hand 13),

againsta piston 111, which is operatively. associated with the member '73, thereby to swing the dresser point 54; from the inopcr'w tire position tha t it normally occupies, down into its operative position in the path of Referringto Figs. 12 and.13, a cylinder 112 is provided at the rear of the machine, the piston 111 being located therein The piping 110 leads from the valve'.77 tome front end of said cylinder. A lever-113, pivoted at 114, has a pin 113 which normally just touches the rear end ofthe piston 111. \Vhen the latter, by fluid pressure actuation,

is moved, the lever 113 is rocked clockwise to the dotted line position of Fig. 13-this action draws bac'kward'ly a link rod 115 to which the lever 113 is connected. The link rod is pivotally connected to the carrying member 73, andhence the action described lowers the diamond 54. A handle 78 is also provided for'rocking the dresser manually. Our invcntio 1, of course, is not limited to the above described use of pressure fluid for disposing the dresser 54 in operative position; obviously, any other type of dresser moving mechanism, such as that disclosed in i the said copending application of Heald, Guild, Burns and Garno, Serial No. 4,466, filed January 24, 1925, may be made responsive to theenergization of. magnet 44.

As before stated, the other operation inaugurated by said engagement is the autoinatic amplification of the reciproca-tory path of table 1, to. carry the wheel 5 past the dresser 54. As shown. in Fig. 1, the left hand.

table dog 8, which limits the right hand movement of table 1, is carried .bya block 79, which instead of being secured directly to the table 1 as in the case with the block of dog 7 is mounted so as to be capableof sliding freely. longitudinally of said table. Under normal conditions, when the table is making its usual workingreciprocations to traverse the grinding wheel 5 back and forth within theworkpiece, the block 79of dog 8 is held'in definite spaced relation to a block 81, which latter, the same as the block80 of right hand dog 7, is a stationary block adapted to maintain its predetermined setting or adjustment longitudinally of the table 1, asggiven it by any suitable adjustmentof adjusting and holding devices, such for instance, as the hand screw nuts 82,82 applied to both blocks 80 .and 81 and engaging with the screw rack 83 on the table 1. a I d -'The device employed to hold the slidable block 79 in spaced relation to the fixed block 81 is here shown as a latch lever 84 pivoted at 85 on block 81, and. having its free end disposed bygravit-yin abutting relation to a shoulder 86 on block79, thereby holding the block 79 at a predetermined distance to the right of block 81. When the latch member 84 is lifted to free its end from the shoulder 86, the normal connection between the slidable block 79 and the fixed block 81 is i broken, and when this occurs on the right hand movement o'ftable 1, the dog 8 will bear without effect against the, member 9. Thus the right hand movement of the table 1 on this particular strokewill be extended beyond the usual reciprocatory working path, and the grinding wheel 5 will be carried out of the hole in the workpiece to a point just beyond that occupied by the dress, ing device, which latter, as already described,

has been moved into operative position as the amplified right hand travel of table 1 begins.

This amplified right hand travel of table 1 involves relative sliding movement between said table and the block 79, owing tothe obstruction which the reversing member 9 imoses against the dog 8 to prevent the block H 9 from moving with the table; finally, the

block 79 brings up'against the block '81,

whereupon the solid backing thus afforded for the block 79 enables. the dog 8 to shift the member 9. v This procures reversal of the table 1, and theleftj, hand movement of said table .thusinauguratedis caused to restore the parts automatically to normal position in,

the following manner. v p

i A member 87 pivotally mounted on the frame of the machine has a pair of inclined surfaces 88 and 89 for cooperation, respectively, with inclined surfaces 90 and 91 at the lower corners of the block 79'. A spring 92 presses said member 87 upwardly. In the normal grinding operation ofthe machine when the blocks 79 and 81 are connected by latch 84:, the surfaces 88 and 89, although in the path of block 79, offer no effective ob'- struction ,to the back andforth travel of said block-in unison with the table 1,.it being obvious that when either lower corner of the block under these conditions strikes either of the bevelled surfaces 90 or 91, such contact will wedge the spring 92 downwardly. saidspring yielding sufliciently to allow the block 79 to pass over the member 87. However,

when the block-J9 has been freed from the block 81 as above described, to, amplify a. single right hand stroke of the table 1, the ensuing reversal of said table, with the block.

- 2'9 still free, tindsthe surface 88 in position to contact with the corner 90 of' said block, and under these conditions; the obstruction offercd sufficient to overcome whatever friction there may be tending to cause the block 7 9 to move totheleft with the table -.The block 79; being thus held stationary while the table 1 and block 81 continueto move to the left, the latch member 84 finally resumes its normal position relative: to the block 7 9 the end of said latch member dropping behind the shoulder 86 .and the parts being thus automatically restored to normal position at the conclusion of each single amplified reciprocation of the t ble 1. Movement of the lever arm 70 is ad-pted to the latch 84, the former having a roller 70, which normally lies just underneath. said latch.

The magnet may be seen in dotted lines in Fig. 1, being shown as. inclosed in a box like structure 93 on the front of the machine frame. The magnet is: located directly behind the magnet 4.4, andthe same pivot 71 that serves to hold the armature 69, lever arm and extension 76-, serves also to hold an armature 94: and arm 95 associated with elec-, tromagnet 45. As heretofore stated, energization of ma I ct 45 is adapted to cause final separation ol work and wheel, and this is effected in the following manner z-' Attraction of armature 94 lifts arm 95, in terposing the free end of the latter in the path of table dog 8, which dog, as heretofore pointed out, normally on the right hand working stroke of the table, strikes and moves the reversing member 9 to causes. reversal in the direction of table travel. The dog 8 pivotally mounted at'96 (see Fig. 1) on'the carrying block 79 and normally rests by gravity against a pin 96. When the arm 95, as above described. moves upwardl into the pathof do 8, the free end of said og onthe right han movement of the table, engages with and rides upon the u wardly inclined surface of arm 95, and is t us carried clear of reversing member 9. The table 1 therefore, continues its movement to the ri ht, ca'rrying the grinding wheel 5 out of t e work and well past the dressin device, being finally brought to a stop 6 means, such, for example, as sclosed in the aforesaid copending application of Heald and Guild, Serial No. 629,882, filed April 4, 1923.

Referring again to Fi s. 3 and 4, a shaft 97 is rotatably carried by t e box 93 and a lug 98 attached to; said box. An actuating arm 99 has a hub 100, which latter is fastened to the shaft 97. The shaft 9'! also serves as a pivotal mounting for a second actuating arm 101. Fastened to the front of the shaft 97 ing operation by reason o any suitableis a. lever 192 The connector 62 is pivotally connected to lever 102'. The connector 66 is attached to the outer end of actuating 10 1. Attached to the left hand block 81 are a pair of switch operating dogs 103 and 104. dog 110:3 is in'the pathofthe arm 99 and adapted to actuate it whenever it is: moved past said arm. The dog 105: which, as will be seen from 3, is somewhat different in shape from the dog 1 03, is in the path of the actuating arm 101, and is adapted to depress the latter whenever it passes it. In the normal reciprocatory travel of the table to grind a workpiece, neither the arm'lOl nor the arm 99 is actuated by the said operating dogs 103 and because in such working position the {table 1 doeslnot move out far enough. When the table I withdraws to erform the dressi the lifting of the latch 8d as already described, the dog 103 strikes and tilts the arm 99 to a position shown by dotted lines in Fig. 3, as: the said table moves outwardly, and again as the said table moves inwardly, this latter time in reverse direction, but to same extent. double actuation of the arm 99 lifts the connector 62 twice, thereby moving the pawl 61 twice to operate the ratchet segment 57.

When the table 1 is in the position shown in Fig. l, which is the sition it assumes while the operator is taking out the finished workpiece and inserting an unground one, the ratchet segment 57, pawl 61 and associated parts, assume the full line position of Figs. 3 and i witli the bridge 55 as shown in full lines in liig. 5. The operator having inserted a new unground workpiece 6 in the chuck 6 of the workhead 3, grasps a lever 105 which is connected, in a manner not necessary to be described herein, to the rever ing member 9. The operator shifts'said lever- 105 to the left, thus moving the reversing member to the right and causing the table 1 to move to the left. The table dog 8, on striking the reversing member 9, is lifted thereover, thusdisposin the member 9 between the actuating dogs and 8. Prior to this the'dog 103 strikes the arm 99, as shown in Fig. 6, and moves the bridge 55 to the position shown in said figure, thus electrically connecting the stationary contact terminals 52 and 47. The grinding wheel 5 now roceeds to enlarge the internal diameter of t e workpiece 6, thetable'l re- 6. As the workpieceB is enlarged, at a predetermined point determined by the adjusting screw 28, contact is made between the points 32 and 35.

Referring to Fig. 5, it will be seen that electrical energy from the generator G now passes along the lead 43 through the electromagnet 44, thence by way of lead 46 to terminal 47 of the switch 48, thence bybridge 5 55 to terminal 52, thence by lead 50 across the contacts 32 and 35, thence through the machine frame, since the lever 24 is grounded, back to the generator again. This causes attraction of armature 69, and thus the arm is raised, lifting the latch 84, whereupon the table 1 withdraws from the workpiece for a limited distance. At the same time, as already described, the diamond dressing point 54 is lowered into the path of the grinding wheel 5 andthe latter is dressed and trued thereby. The grinding wheel 5 then returns to make contact with the workpiece 6 again;

As. the table 1 moves outwardly for this dressing operation, the dog 103 again strikes arm 99 and rocks it, bringin the bridge 55 to the position shown in Fig. Immediately thereafter the arm 99 is rocked in the reverse direction and the bridge is-brought to the position shown in Fig. 8, where the terminals 47 and 53 are connected. At this time, as the wheel 5 enters the workpiece 6 again, the terminal 32 is still in contact with the terminal 35,.but insomuch as the bridge 55 has moved away from the terminal 52, the wheel dressing instrumentalities are not immediately brought into play. Instead, the grlnding wheel 5 continues to reduce the workpiece 6, but with a greatly lessen'ed'spark, owing to the fact that the ressure between the two,

due to the springmg of the spindle 10, has been removed by the-dressing and truing operation, which has reduced the wheel in size. When, however, the grinding has proceeded far enough to brin the terminals 33 and 36 into contact, thew eel dressing operationis repeated. At this time, the current goes from the generator again by way of electromagnet 44 and lead 46 to stationary terminal 47. Thence, it jumps by means of the bridge 55 to the stationary terminal 53, 'and then, by way of lead 51, across the contacts 33. and 36 to ground again. This causes the machine to go through exactly'the same operation as before, and, consequently the bridge 55 is moved again. I

It will be noted that we have provided adouble motion to the bridge 55 for eacham-- the machine shown. because as fully described in the application of Heald and Guild, Serial No.25,900 and as illustrated in Figs, 12 and 13, the said diamond 54 is returned to inoperative position by 'a cam 1 16 carried by the table 1, a surface 117 of which engages a roller 118 Ma forward extension 119 of the lever 113, and it is desirable that this mechanical return movement should be unopposed by pressure in the diamond operating; cylinder 112.

The wheel 5 is now back in contact with the workpiece 6 and proceeds to take the final and finishing cuts under no more pressure between wheel and workpiece than is necessary to obtain a cutting for the finish of the workpiece, owing to the double dressing and truing operations. When the workpiece 6 reachesfinished size, the contact 34, on the lever 24, engages the stationary contact 37, and at this period, the electromagnet 45 is energized] The current to energize magnet 45 proceeds, by way of lead 43, through said magnet 45 to terminal 37 by way of'lead 49, thence to terminal 34 and back to ground. It will be noted that, at this time, it is impossible for the electromagnet 44 to be energized, since the bridge 55 has moved one station beyond the last energizing position, as shown in dotted lines, Fig. 5. Subsequent movements of the pawl 61 after the parts have.

reached this position avail nothing, since the pawl merely rides up on the circular periphery of the member 57. Upon right hand movement of the table 1, therefore, the dog 8 is lifted by the arm and, consequently, the table proceeds outwardly to the position shown in Fig. 1, where it comes to rest. As the table so moves outwardly, and then only,

the dog 104, which is in etfecta double cam member, comes into contact. with thelever arm 101, depressing the same, thus moving downwardly the connector 66 and raising the pawl 63. At that point thecoilspring 67 comes into operation and returns the ratchet segment 57, the bridge 55, the shaft 58 and all associated parts to the original position.

This is possible because a shield member 106 holds the pawl 61 out of engagement with the segment 57 till its stroke has been commenced. Figure 9 illustrates the action here,

showing the pawl 63 engaged by the end of the segment 57*.

It will 'be noted that the contact terminals 35 and 136, which bring the dressing instrumentalitieSinto play, are adjustable in and out, as bimeans of thumb nuts 107 and 108. Likewise, the position of final withdrawal" is adjustable by means of the thumb nut 109,

and as already described, the lever 24 as a unit may be adjusted in and out by means ofthe screw 28. Thus the stage in the reduction of the workpiece at which the first and second dressing, andalso the final withdrawal, take place can beireadily. determined. We have nuances 7 found that it is advantageous to cause the for extending the amplitude of said reeipro- H first and second operations to come cation a plurality of times d o the operclose together and to set the diamond 54 back ation on a single'work-pieee, wherehy to dress of a vertical plane of tangen y to the internal said wheel a plurality of times during said surfaceof the workpiece at the first predeteroperation.

position. The spring of the wheel spindle 10, whiehis combination with a grinding wheel, a work then at its maximum phase, causes the wheel holding device, and means for reciprocating 5 to contact with the diamond 54 and thus be one of said partsrelative to the other, of a dmd and trucd. As aforesaid, the wheel Wh el device having a single operno proceeds to cut the work with greatly difl v po i i n in he Path of Said spark, and the second dr sing wheel, and automatic means for extending operation'will take la e r ti ll t, that the amplitude of mid, reciprocation a plutime when the said plane of tangeney reaches fillies during h p r i n OH the diamond, Thu a l l d i g d single workpiece, wherebytodresssaid wheel truing of the wheel is aecomplishedmiththe plurality of films during i perati ndiamond 54 always reaching the same dres c ine comprising, in coming point, yet the wheel 5 is not excessively PP reduced, asthe spring of the spindle allows and liming tool o n d 011 d pp enough cuts to be taken between dressing op- K183115101 causing mllfive mvm crations so that the contacts 323 5 and 19 and Work holder mm p 3336 will not be made simultaneously. 4 mlttmg It is obvious that by merely providing an dude the PB d the F m the additional pair of contacts in the box 22, an g o l e travl of and grinder, time additional stationary terminal in the switch P g two relative have]? 48 and some more teeth in the segment 57, we 0mm? means or from the Shorter could provide for a triple dressing operation, a g to the longer and again a and in fact, any number of operations, but R y of limes nr ufi grinding of a beyond a certain number, such would only angle Workplw but P g 0f tend to excessively reduce the diameter of the the longer g when the mg mechamsm wheel 5. As it is, with a double dressing and has reached oth predewnnined position truing operation, bell-mouthing? of the theflfol'esald 111m 3511111195011 workpiece is practically eliminated, and the 0f range 8 we such finish d Piece h a th i t l iumptlon after the second alteration to the onger n e. N As re believe ourselves to be the first to 4- A grinding machine compnsmg,mcomprovide means for automatically a billafion, a g n 8 support, a work holdmovement of the feed screw 11 resent t0 h ng r (P tron o wheel at a plurality 'of stages in 1' a fil'llmg tool mounted on said support,

e course of the reduction of a workpiece, means f r lng rela ive traverse between we wish to claim the same broadly, however the g 5ml 1 1 support, lncluding carried out, and 'we note in this connection 11199-115 Permitting mg the W f said that while the invention is described as apverse between two ranges, one of which plied in connection with the work cali mes the parts through operative traverse mechanism invented by Heald, Guild, B between the grinder and work holder alone, and Garno and described in their said appliand the other f which carries the parts cation Serial No. 4,466, it could equally well g g operative raverse between the be in connection with the invention of g d o he Work holder and truone of us, viz, Guild, as shown in application g 1, a Wot]; sizing m, means Serial No. 48,734, wherein is shown mechag t Into who wh n 1ml Work niam to automatically inaugurate the dressmec reaches a predetermined position ing and truing of the wheel in response t for altering the said traverse from the shortf f l jgtomatically wings ,with means or compensa v, "causmg resum the wear on the grinding wheel. m ans preventing immediate ent re In the subjoined claims, the words recipsumptlon of the longer range despite the rebate, reciprocation, and trav r am mamtenance of sizingmechanism at said to be taken to'mean to and fro movement and predetermined pqsltio and means to again nottoinclude a movement to a position folextend the traverse to e longer range when hired a cesation of movement. said work sizing mechanism reaches the see 2 ii 'dffifiltn dm grindingmachine,.the agrin' 'e, agrin' combination with a grinding wheel, work $1 8 Wh el device normally out holding means, and means for reciprocating of the path of said om; of relative to the other, of a sizmgm a work means V0 to movewheel deviee,'and automatic means ment of said sizilig mechanism for bringing said, range,

2. In an internal inc, the.

the of said traverse to insaid dressing'device into the path of said wheel, said dressing device occupying a given point, and means for causing said wheel to be dressed at a plurality'of different stages in the reduction of said workpiece by relative reciprocation between "said wheel and said dressing device, said dressing device being at such times at said given point.

6. In a grinding machine, a grinding Wheel having a reciprocatory working traverse relative to the work, a truing tool, a work sizing mechanism, means set in operation by said I sizing mechanism for automaticallyincreasing the t averse of said wheel to dress it with said truing tool when the work reaches a first predetermined size, means brought about by' said increased traverse for resuming normal .traversebetween said work and Wheel, and

means for again automatically increasing the traverse of said wheelto dress it with'said truing tool upon said work reaching a subsequentpredetermined size.

7 In a grinding machine, a grinding wheel having a reciprocatoryworking traverse relative to the work, means operable at a plurality of intermediate points in the grinding o f each workpiece for amplifying said traverse to carry said wheel through a wheel dressing position, a grinding wheel dresser for operating on said wheel in its passage through said dressing position, and automaticmeansfor avoiding thedressin g'ot' said wheel thereby on its final passage throu h the dressing position at the conclusion of t e grinding of the same workpiece. 7 y 8. In a grinding machine, a grinder, a

wheel dressing device normally'out' ofthe f path of said grinder, a work sizingimecha nism, and meansautomat-ically set 1n opera- 7 tion by said sizing mechan sm for dlsposmg said dressing device in the'path of said wheel net-ic inaugurated means for moving said diaa plurality of timesduring theoperation on 1 a single workpiece.

2, In a grinding machine, a grinding wheel, Wheel dressmg mechanism comprlslng a plvotally mounted diamond, and electromagmond into the path of said wheel a plurality of times during the grinding operation on a single workpiece. I A

10. In a grinding machine, a grinding wheel, an electrical switch mechanism adapt ed to control a primary wheel dressing operation and a secondary wheel dressing operation, a recip'rocatlng table,-'and means actudevice out or opcrativeposition with respect;

to the grinding wheel between two or more of said dressing ope 'ations. I

12.'In a grinding machine, the combination with a grinding wheel, Work holding means, and means for reciprocating one of said parts relative to the other, of a dressing device, and meansfor causing said dressing device to dress and true said grind ng wheel a plural butdeterminate number of, times during the grinding operation on a single wo'rkpiece,said detcri'ninate number of dressings bein'gless in number than the number of reciprocations between the first and the .last dressing operation.

13. In a grinding machine, the combination with a grinding wheel,v vork holding means,

means for reciprocating one of said parts relative to the other, and means for giving said parts an intermittent cutting feed. one in relation to the other, of a dressing device, and meansffor causing said dressing device to dress and true said grinding wheel a plural but determinate number of times during a given advance of said intermittent cutting :teedgsaid determinate number of dressings beinglessin number than the number of separatefeed actu ations bet-weenthe first and the lastdressing operation.

14.. In a grinding machine,the combination' with; a grinding wheel, work holding means, means for reclprocatlng one of said parts relative to the other, and means for transversely feeding one of said parts relative to the other,

of automatic means for extending the amplitude of said reciprocation aplurality of times during the operation on a single workpiece at different stages of said trainsverse feed. and dressing means for dressing said wheel at said amplified reciprocations. 0 WALDO J. GUILD. LEWIS CLIFFORD KENYON ill) CERTIFICATE OF CORRECTION.

Patent No. 1,684,486. Granted September 18, 1 928, to

WALDO-J. GUILD ET AL.

It is hereby certified that error appears in the printed specification of :the above numbered patentrequiring correction as follows: Page 2, line 111, for the word "manipulated" read "multiplied"; page 7, line 90, claim 3, after the word "travel" insert the word "and"; same claim line"94, beginning with the word 4 "but" strike out all to and including the word "range" in line'l00; same page,

line 110, claim 4, strike out the word "and" and insert the same before the word "means" line 119; same claim, line 122, strike out the comma and words "and means to again extend the traverse to the longer range when said work sizing mechanism reaches the second predetermined position", and insert instead "but causing resumption of the longer range when the sizing mechanism has reached another predetermined position, the aforesaidmeans that causes resumptionoi; the shorter range again causing such resumption after the second alteration to the longer range"; page 8, line 106, claim 14, for the misspelled word "trainsverse" read "transverse"and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the ease in the Patent Office.

Signed and sealed this 20th day of November, A. D. 1928.

p M. J. Moore, (Seal) Acting Commissioner of Patents.

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