US1841809A - Grinding machine - Google Patents

Description

Jan. 19, 1932. R. N. HEALD ET AL GRINDING MACHINE Filed May 31, 1928 6 Sheets-Sheet l WMWW M u fl mg r h fiwnw a 0 mm 4 4 d RERC Jan. 19, 1932.,

R. N. HEALD ET AL GRINDING MACHINE Filed May 31, 1928 6 Sheets-Sheet 2 gwwmtz Roger N. Hamid, Edward. i'lT'cu Por' Ru? h H- Quibq Gal 2 R. N. HEALD ET AL 1,841,809

GRINDING MACHINE Filed May 31, 1928 Jail. 19, 1932.

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GRINDING MACHINE Filed May 31, 1928 6 Sheets$heet 5 Roger N-HQCLECL EcLwgrcl ("LTQgEor' Jan. 19, 1932. R. N. HEALD ET AL GRINDING MACHINE Filed May 31, 1928 6 Sheets-Sheet 6 G (Milt,

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Patented Jan. 19, 1932 UNITED STATES PATENT OFFICE ROGER, N. HEALD, EDWARD M. TAYLQR, BALPH A. QUIMBY, AND J. HIGHIBEBG, I OF .WORGISTER, MASSACHUSETTS, ASSIG-NOBS TO THE HEALD .LQTACHINE COMPANY, OF WORCESTER, MASSAGEUSETTS, A CORPORATION OF MASSACHUSETTS ennmme MACHINE J Application'filed liay 31,

The present invention relates to improvements in grinding machines. spects, the improvements are applicable to any. automatic grinding machine which is used for the rapid and eflicient production of a succession of like articles, all ground and finished uniformly to within the closest limits of the desired size. As herein shown, however, the improvements are applied to a grinding machine for performing, practically simultaneously, a plurality of different grinding operations on the same workpiece, an example of such a workpiece being the inner cone raceway of a roller hearing, which requires grinding of the conical surface, between its end flanges, and also of the undercut inner face of one of said flanges.

Apart from this special utility in the production of articles having a plurality of ground surfaces, a most important feature of the invention resides in a new principle adopted in order to secure accurate grinding of cylindrical or conical surfaces. This is predicated upon a feeding or approaching movement between rotating grinding element and rotating workpiece, that carries one of these parts in a rectilinear path, with its axis always at a constant distance from a given plane with which the surface of the grinding element is maintained tangent,- so that when the rotating parts become mu-' tually tangent, in a plane at right angles to said given plane, the workpiece has been reduced by grinding to the exact desired size. In the particular machine herein illustrated, the action above describedis obtained by imparting to eachworkpiece a descending and ascending movement, relative to the grinding wheel,there being a dwell at the upper and lower limits of the movement, in one case to permit removal and replacement of the workpiece, and in the othercase to allow a second grinding operation on the workpiece to be effected.

- According to the invention, the grinding takes place automatically,the operator having nothing to do other than to remove the finished workpieces from the work-rotating spindle, and place fresh unground work-f pieces thereon: Thismanual operation takes In certain re- 1 1923. Serial No. 281,888.

but a moment, as the machine automatically causes the work-carrying spindle to rise when ing place when the work spindle is raised, so

that it will not interfere with the flanges of the workpieces.

In order that one of the workpiece flanges may be undercut, one of the grinding wheels must be caused to approach relative to the workpiece, substantially parallel to the axis of the latter; while the feed of the other grinding wheel, relative to the workpiece, is in a direction substantially at right angles to said axis. It is thus an object of the invention to give the grinding wheels and the workpiece the motions that will allow them to come together in this fashion.

The above and further objects of the invention will more fully appear from the following detailed description, taken in connection with the accompanying drawings, in which- I F ig, 1 is a rear elevation ofa grinding machine in accordance with the invention, as viewed from the left side of Fig. 2.

Fig. 2 is a plan view of the machine.

Fig. 3 is a, fragmentary plan View, on a larger scale than F ig. 2, showing one of the grinding wheels and its mounting upon the machine frame.

Fig. 4 is a fragmentary elevation. from the front of the machine, showing the same grinding wheel head and its supporting Fig. 6 is an elevation of a dressing device and the mounting therefor.

Fig. 7 is a fragmentary sectional view, showing a certain clutch and brake mechanism.

Fig. 8 is an isometric view showing the driving mechanism of the machine.

Fig. 9 is an elevation of a certain counting mechanism and a fluid pressure pump, together with a diagrammatic representation of the fluid pressure'system which actuates the rinding wheel tables or carriages.

Flg. 10 is a sectional View on the line 1010 of Fig. 9. v

Fig. 11 is an isometric view of a certain cam.

Fig. 12 is a large scale view of one of the workpieces which is required to be ground in the machine.

Like reference characters refer to like parts throughout the drawings.

Referring firstto Fig. 12, the type of workpiece, designated a, which the machine is particularly designed to grind, is the inner cone member of a roller bearing assembly, said member presenting an exterior ground conical surface a, at the extremities of which are the roller retaining flanges 6 and c, the former required to be undercut, by grinding as shown.

The machine is mounted upon a suitable frame 1 and provides a workhead 2 carried by a slide 3, which is adapted to be vertically reciprocated in slideways 4 provided by the frame. Journalled in the workhead 2 is a workholding spindle 5 which provides beslide 3 descends.

yond its shouldered portion 6 the springs (see Fig.8) by which the rotation of the,

workpiece a, when impaled upon the end of the spindle, is secured. Referring now to Fig. 8, the work spindle 5 is rotated from a pulley 7 on shaft 40 by means of a belt 8, which passes around said pulley and a pulley 9 fastened to the spindle. By means of an adjustable tightener 10, which is held against the belt 8 b means of a heavy spring, not shown, the elt is kept at constant tension despite the rise and fall of the slide 3.

The workhead 2 is given a vertical reciprocato motion, with a long dwell at the upper position, in order that each ground workpiece may be removed from the work spindle 5 and an unground workpiece placed thereon. The lower position is the grinding position, and the upper position is the work changing position; as will be hereinafter described, automatic means is provided to stop the rotation when the spindle reaches its upper po. sition and to start it 'rotating again as the Referring now to Fig. 1, the machine provides amotor 11, the shaft of which provides tenedto a shaft 15, to which is also fastened a spur gear 16, in mesh with a spur gear 17 on a shaft 18. See Fig. 8. The shaft 18 has a worm 19 fastened thereto, which meshes with a worm wheel 20 mounted on a horizontal shaft 21, the right hand end of which carries a cam 22. See Fig. 8 in connection with Fig. 1. Attached to the slide 3 by means of a stud 23, is a cam roller 24 which rides on the periphery of the cam 22, and thus the rotation of this cam causes the slide 3 to re ciprocate vertically.

Referring particularly to Fig. 2, the machine provides a grinding wheel 25, adapted to grind a cylindrical or conical surface a on each of the workpieces a. The machine also provides a grinding wheel 25a adapted to grind a flat or annular surface on each workpiece, such asan undercut portion on a flange Z) of the workpiece. To those ends, the grind ing wheel 25 is carried by a wheel head 26 which, in this embodiment of the invention, is a motor, said wheel head or motor being angularly and longitudinally adjustable;

transverse feeding means being also provided to adjust the grinding wheel to different sized workpieces and to compensate said wheel for wear and for truing by dressing, as will be hereinafter described. The grinding wheel 25a is carried by a wheel head or motor 26a which, as in the case of the motor 26, is angularly and horizontally adjustable, and can be positioned relative to the work by transverse feeding means. Additionally, however, the wheel head 26a is given a regular reciprocating motion in the line of the said transverse feed in order that the aforesaid undercut flange b may not be destroyed when the workhead rises. In other words, in the machine of the present invention, the workhead rises and falls, (the rise thereof being an indication to the operator that a fresh underground workpiece should be placed on the spindle 5,) and in order that the grinding wheel 25a may out under the side of the flange b, said wheel is given a reciprocating movement, timed in relation to said rise and fall. In connection with both wheel heads 26 and 26a, there is provided fluid pressure operated means to cessive workpieces, or only after a predetermined number of pieces have been ground, ac-

cording as a certain counting mechanism,

which will be described, is set.

Referring now toFig. 5,.the wheelhead 26 is mounted upon a cross slide 27 that is slidable in transverse ways, not shown, provided by an elongated table or carriage 28. Said table 28 provides journals or bearingsfor a screw shaft 29 whiclrpasses through a nut, not shown, attached to the cross slide 27, and

by turning the screw shaft 29, said cross slide and, consequently, the wheel head 26, may be fed towards or away from the axis of rotation of the work spindle 5. The

' details of mounting of the screw shaft 29 and the cross slide 27 on the table 28 have not been illustrated herein, since the construction of such parts is well known in this art. The table 28 is in turn slidable longitudinally in ways 30, Fig. 1, provided by a base 31 which rests upon the machine frame 1,

being pivotally fastened thereto by means of abolt 32-, and adjustably fastened thereto in any angular position, by means of anarcuate slot 33 inthe said frame and bolts 34, 34 carried by the base.

v In similar fashion the wheelhead 26a is mounted upon a cross slide 27a that is slidable transversely in ways, not shown, provided by a turret 35. The latter is rotatively adjustable upon a table 28a that is in turn slidable longitudinally in ways, not shown, provided by a base 31a, Said'base is pivotally fastened to the frame 1 by means of a bolt 32a; as in the case ofthe base 31, bolts 34a, 34a and an arcuate slot 33a are provided to angularly position base 31a? Likewise, as in the case of the wheelhead 26,-a screw shaft 29a is provided to position the cross slide 27a, said shaft passing through a nut, not shown,

7 attached to the cross slide 27a; but in order to obtain the regular reciprocating motion heretofore referred to, this screwshaft is journalled in a somewhat different manner, as follows:- 3

As best shown in Figs; 2 and 3, the screw shaft 29a passes thfough and is suitably journalled in thrust bearings provided by a member 36 located in a housing 37 that extends upwardly from and is fastened to the turret 35. The housing provides a bearing 38 in which is located a pin 39 attached to a forked bell crank lever 40, the latter being thus pivotally mounted upon the housing. See Fig. 8. The lower forked portion of the lever 40 provides shoes 41, 41 that. fit in a groove pro- 4' vided in the side of the member 36. Assuming the bell crank lever 40 to be stationary, it is obvious that the shaft 29a will be held from longitudinal displacement by reason of the thrust hearings in the member 36, and the cross slide 27a will .bemoved on the turret in response only to turning of said shaft, because of its action onthe nut attached to said slide. Just prior to the rise of the workhead 2, the cross slide is moved to the right (Fig. 2) entirely independently of rotation of the screw shaft, this being accomplished by movlng the bell crank lever 40 in acounterclock wise direction, Fig. 8. This is brought about in the following manner :Referrin to said Fig. 8, the shaft 21 which; as hereinbefore described, rotates practically continuously and carries the cam 22 which causes the workhead 2 to rise and fall, has fastened to it another cam 42. Pivoted at 43 tothe machine framefis a lever 44 the lower end of which provides a roller 45 in contact with the periphery of said cam 42. The roller 45 is urged towards the cam by means of a spring 46 attached to one arm of the lever 44; a third arm 47 integral with the lever 44 provides a swivel pin 48 attached to a connector rod 49. The upper end of the r6d 49 is connected, by means of another swivel. pin 50 to the bell crank lever 40; thus the grinding wheel 25a moves in and out, in timed relation to the rise by the grinding wheels are drawn across the I point of-dressing devices fastened to the underlying bases 31 and 31a that support the tables. These withdrawal motions must take place when the spindle 5 is raised, since the grinding wheel 25,- during the grinding operation, is located between the flange b and a flange a on the workpiece, and to move it in adirectionparallel to its axis would result in cutting into one or the other of said flanges. The dressing operation is therefore timed to take place when the workhead is raised, which is the signal for the operator to change workpieces. v

As shown'in 8, the shaft 21 which carries the cam 22 that raises and lowers the workhead, and the cam 42 that shifts the grinding wheel 2512 at right angles to its axis so that it may leave a finished workpiece without destroying the flange 6, provides a third cam 51 that sets in operation the dressing instrumentalities. Said cam 51 as shown in Fig. 9.is located in a box-like structure 52 that is provided on the back of the machine. See Fig. 1 for the location thereof. Once during each revolution of the cam 51 it depresses a roller 53 carried bya lever 54 pivoted at55 to the machine frame. An arm 56, pivotally mounted on a shaft 57, is connected by means of a link 58 to the lever 54, and consequently the lever and the arm move together, the arm 56 providing a spring 59 which tends to raise these parts and keep the roller 53 against the periphery of the cam 51. Pivotally mounted at 60 on the arm 56 is a pawl 61 which is pressed, by means of an internal spring, not shown, reacting against the pivot stud, towardsa ratchet wheel 62. which is mounted on the shaft 57. Except when the parts are drawn downwardly, as described, the pawl 61 is kept from contactwith the ratchet wheel by means of a pin 63, but when the pawl moves downwardly, it is allowed to contact the ratchet wheel, by reason of the configuration of said pawl, and the motion imparted to the ratchet wheel is suf- Referring to Figs. 9 and 10, the ratchet Wheel 62 is fastened to a cam member 64 mounted on the shaft 57. Counterclockwise movement of the ratchet wheel 62 in response to the actuations of the pawl 61 is opposed by a coil spring 65 which surrounds part of the hub of the cam member 64:, one end of said coil spring being fastened to a pin 66 provided by the casing 52, and the other end being secured to said cam member. However, retrograde or clockwise movement of the ratchet wheel 62 is normally prevented by means of a hold pawl member 67 pivoted on a stud '68 in the casing 52, and urged against the ratchet wheel by means of a compression spring .69.

The cam member 64, which to all intents and purposes, is integral with the ratchet 62, is for the greater partof itsperiphery circular in form, but provides a cam projection 70, which, when moved into engagement with a roller 71 provided by a lever 72 pivoted on the aforesaid stud 68, moves said lever clockwise against the tension of a spring 73. This action inaugurates the dressing operations in the following manner.

Referring to Figs. 2 and 9, the machine provides a pump 74 of the usual sort provided by machines of this character, said pump being adapted to create a pressure on a suitable fluid, such as oil, and said pump being driven in any desired manner, as by an electric motor 75.

From the discharge end of the pump the fluid is led by piping 76 to an entrance port 77 in a valve casing 78. In the valve casing 78 is a slide Vlave 79, which is connected at 80 to the lever 72. In one position of the valve member 79 (the position shown in dotted lines), the pressure fluid is admitted to piping 81, which branches into two parts 82 and 82a and leads to the right hand end of cylinders 83 and 83a. Said cylinders are located in the bases 31 and 31a, respectively,

- and'contain pistons, not shown, connected by piston rods 84 and 84a to the tables or carriages 28 and 28a, respectively. In the position of parts shown in Fig. 9, which is the normal position, the'pressure fluid is made active against the'right hand end of each iston (see Figs. 4 and 5), and this holds th carriages to the left so as to maintain the grinding wheels 25 and 25a in the path of the workpiece, in position for immediate grinding. Accuratepositioning of the tables isobtained by means of stops 85 and 85a'located on the bases 31 and 31a and cooperating adjustable stops 86 and 86a carried by the tables 28 281;, respectively. In this position of the valve 79, piping 87 and 87a, connected to the left hand ends of the cylinders 83 and 83a and which merges into a single pipe 88, is connected to an exhaust port 89 provided by the casing 78.

When, by action of cam 70, the left hand end of the lever 72 is raised, the valve member 79 is lifted which makes the pressure fluid active against the left hand ends of the pistons in the cylinders 83 and 83a, by way of the piping 88, 87 and 87a; at the same time, the piping 81 that leads to the right hand ends of the cylinders 83 and 83a is connected to an exhaust port 90. Thereupon the tables 28 and 28a move to the right and carry the grinding wheels 25 and 25a past dressing devices 91 and 91a located on suitable dressing stands 92 and 92a (see Fig. 6) fastened to the bases 31 and 31a, respectively. I

Outward travel of the tables 28 and 28a causes temporary failure of the power that raises and lowers the work carrying slide 3,

in order that the dressing operation may he certainly finished and the grinding wheels returned to their normal position before the slide again travels downwardly for the commencement of another grinding operation. To that end a cam member 93, which is shown in. perspective in Fig. 11, is attached to one of the tables (actually to table 28, as shown), said cam member providing inclined inwardly facing surfaces 94 and 95 that engage and press inwardly the outwardly extending arm of a rocker member 96, behind which is a push button switch. In this man'- ner current to the motor 11 is cut off, the circuit being immediately reestablished upon reverse movement of the table 28.

Said reversal of travel of the two tables is brought about by the same member 93 that provides the cam surfaces, and occurs'when said member strikes and turns an arm 97 attached to a valve 98. See Fig. 9. The valve 98 is located in the piping 87a, which is the branch piping that leads the pressure-fluid to the cylinder 83a that actuates the table 28a, this being the table that does not actuate the arm 97. Normally, and before actuation as above set forth, this valve 98 allows fluid to pass to and fromthe left hand end of the cylinder 83a, but when turned by the aforesaid means, the fluidis shut off from said cylinder, and is directed into piping 99 that leads to a small cylinder 100 located inside the casing 52. In said cylinder 100 is a piston 101, and when fluid under pressure enters the cylinder, the piston 101 is raised. This action forces upwardly a pin 102 a ttached to the hold pawl member 67 and thus releases the hold pawl. 1

As soon as the hold pawl 67 leaves the teeth of the ratchet wheel 62, the spring 65 turns the ratchet and the cam member 64 in a clockwise direction, the parts coming to a stop when a pin 103 carried by the ratchet strikes a stationary pin 104, the position of which is adjustable. Retrograde movement of the cam member, as described, causes thecam portion 70 to leave the roller 71, whereupon the spring 73' moves the valve member 79 downwardly. This makes the pressure fluid active against the right hand ends of the cylinders 83 and 83a,"and thereby causes the tables 28 and 28a to travel to the left, moving the grinding wheels 25 and 25a past the dressing devices 91 and 91a and completingthe dressing and truing action. The

tables come to a stop when the movable stops 86 and 86a on said .tables strike the stationary stops 85 and 85a, but before this happens, the arm 97 has moved to restore the valve 98 to its original position. Referring to Fig. 5, a separate cam member'105 is adj ustably located on the table 28, and when the table 28 moves to the right this cam member passes over the arm 97. When, however, subsequent to the actuation of the arm 97 by the cam member 93, the table 28 returns to the left, the arm 97 is up, and under these conditions said arm is in the path of the cam member 105, which strikes it and restores it to its original position. This action takes place before the table 28a can start its return motion, as prior to that time the fluid is locked in the left hand end of the cylinder 83a, and it is for this reason, as well as to be sure that the arm will be moved to its extreme u'pper position by the cam 93, that the actuating devices for the valve 98 are placed on the table that is unaffected by the turning of the said valve.

If the tables were allowed to move full speed until stopped by the stops 85, 86, 85a and 86a, the shock to the parts would be excessive, and to avoid any such shock, both tables are brought to a gradual stop by throttling the fluid pressure supply. .As shown in Figs. 4 and 5, the bases 31 and 31a provide plates 106 and 1060, fastened to shafts 107 and 107a, said shafts having throttle valves 108 and 108a rotatable therewith, which, as indicated in Fig. 9, are located in the fluid supply lines 87 and 82a, respectively. Reverting to Figs. 4 and 5, the plates 106 and 106a each provide a set of pins extending rearwardly therefrom and located concentrically in reference to the axis of the shafts'107 and 1070. As specifically shown, each plate has three of these pins, which are numbered 109, 110, and 111 in the case of plate 106; and 109a, 110a, and 111a in the case of plate 106a. Adapted to engage these pins are depending fingers 112 and 113 adjustably carried on the table 28, and fingers 112a and 113a similarly carried by the table 2811. As the tables start to the right, the fingers 113 and 112, and also the fingers 113w and 112a successively engage the pins 111 and. 110 and also the pins 111a and 110a, which allows the fluid to run full force to carry the tables outwardly at-full speed. The tables continue so to travel until, near the. end of their return stroke, the fingers, in reverse order, successively engage the pins 109 and 110, and also 109a and 110a, which action turns the valves back to their original position, allowing only a slight amount of fluid to flow. Thus the tables are brought to a stop without any shock, but are held in the 'grmding position by the full force of the pressure fluid, since static pressure is not dependent upon the amount of opening that affects free flow.

During the return motion of the table 28, the inclined surface 94 of the cam member 93 strikes the left hand arm of the rocker member 96, and thus actuates the push button switch lyin therebehind, making the electric circuit t at energizes the motor 11, and thus the machine resumes its grinding cycle.

In order that different sized wheels may be used on the machine, the dressing devices are shown in a single illustration, Fig. 6,

are adjustable upon the bases 31 and 31a.

Said adjustment is achieved by means of screws 114 which have collar portions 115,

'91 and 91a are adjustable in and out relaand pass through plates 116 and into the lower portions of the stand 92 and 92a. The dressing devices, preferably diamonds, are held in levers 117 fulcrumed, at 118, said levers being minutely adjusted by means of screws 119 having spannercollars 120 thereon for that purpose. On the other ends of the screws 119 are reduced portions 121 which receive pins 122 provided by the lower ends of the levers 117. The latter are firmly held in any determined position of adjustment by means of screws 123, which can be tightened against the sides of slots 124 provided by the said levers 117.

It will be readily seen that, in the case of the grindingwheel 25, the table '28 always moves said wheel parallel to the axis of rotationthereof. This is so because the cross slide ways provided by the table 28 for the movement of the cross slide 27 thereon, and the ways 30 provided by the base 31 for the movement of the table are both straight, andrconsequently the angular relation of the wheel axis to the base never changes. Therefore, since the ways 30 are formed parallel to the wheela-xis, the grinding wheel withdraws along its axis, and truing thereof produces a peripheral surface which is a true cylinder. The angle of the base 31 upon the machine frame, therefore, determines the angle of the elements on the conical surface 'of the workpiece to the workpiece axis. y

In the case of the grinding wheel 25a, said wheel is always withdrawn m a line parallel to the ways upon the base 31a. The axis of this grinding wheel must always hear some definite angular relation to the machine frame 1, because of the connection of the bell crank lever 40 to the screw shaft 29a. The relationship, in the machine illustrated in the present drawings, consists in perpendicularity of the wheel axis to the workpiece axis. However, because of the interposition of the turret 35, the dressing operation upon this wheel may be made to produce a frustoconical periphery thereon, and the angle of the cone elements may be varied by turning the base 31a upon the machine frame 1. When the base 31a is so turned, it will. be necessary for the operator to turn the turret in the o posite direction, in order that the bell cran lever may continue to hold the member 36 without binding, but when this is done, it will be found that the net result is a swinging of the axis of the wheel spindle in relation to the ways in the base 31a, which determine the direction of travel of the table 28a. To adjust the turret 35 u on the table 28a, a screw 125 and a pair 0 swivel nuts 126 and 127 are provided.

When the grinding wheels have been dressed and trued once, it is obvious that subsequent withdrawal motions of the tables will not cause any of the material of the wheels to be removed, unless some means is provided to cause the dressing devices and the wheels to approach each other. The machine of the present invention provides automatic means to compensate for wear and previous dressing of the grinding wheels, so that each dressing operation may remove some material from the wheels, and the latter be thereby kept to the exact required size in order to produce uniformly ground workpieces. As shown in Figs. 4 and 5, bases 31 and 31a provide adjustable brackets 128 'and 128a u on which are mounted cams 129 and 129a.

he tables 28 and 28a provide pivotally mounted arms130 and 130a, providing rollers 131'and 131a that are adapted to engage the cams and ride thereon when the tables start carry awls 132 and 132a that are spring ,.pressed outwardly. Upon movement of the arms as above described, the pawls engage adjustable inclined surfaces 133 and 133a provided by pivotally mounted members 134 and 13411 that are held in adjustable position by means of springs 135 and 135a, and said pawls are directed inwardly towards ratchet wheels 136 and 136a, respectively. The pawls thus move said ratchet wheels through the distance of one or more teeth, depending upon the setting of'the members 134 and 134a as determined by adjustable thumb screws 137 and 1370. As the ratchet wheels are connected, directly or indirectly, to the screw shafts 29 and 29a, respectively, the said screw shafts are turned and the grinding wheels are caused to approach the plane of the dressing points.

As already described, the work carrying spindle 5 is rotated from a pulley7, which is rotatably mounted on a stationary part Of the machine frame. Said pulley 7 is driven from the motor 11 in the following maner. As will be remembered, the pulley 12 on'the motor shaft drives a pulley 14 by means of the belt 13. Upon the shaft 15, to which said tion clutch, the inner cone 141 of which is keyed to said shaft 140, the pulley 7 isnor I mally caused to rotate with the shaft. The means for holding the inner cone 141 against the outer cone member 142 which is integral with the pulley 7, consists in a spring 143 mounted on the shaft 140 and pressing against acollar portion 144 carried by the inner cone 141, the reacting force being taken by a journal portion 145 provided by the machine frame.

- During the operation of the machine, the spindle 5 is normally rotating; as alread described, however, the motor 11 whic drives it is caused to stop during the dressing operation and it is also necessar that the spindle 5 should cease to rotate w en slide 3 is raised and it is time for the operator to change workpieces. To that end, the slide 3 provides a cam 146 which, as the slide rises, engages a roller 147 provided by a bell crank lever 148 pivoted at 149 on the machine frame.

A toggle link 150, connected to one end of the bell crank lever 148 and connected also to the lower end of a lever 151, causes the latter to be moved in a clockwise direction when the bell crank lever is moved. The lever 151 is pivotally mounted on the stud 152 carried by the machine frame, and provides at its upper end a swivel yoke 153 in engagement with the left hand side of the collar portion 144. When, therefore, the lever 151 is actuated, the inner cone 141 is withdrawn to the right, and the drive for the spindle 5 is interrupted.

In order that time be not wasted waiting for the spindle 5,. to stop, a brake mechanism is provided which comes into operation coincident with the declutching action just described. As shown in Fig. 7, the lever 151 provides a boss 154 through which extends a screw bolt 155, which is attached by nuts 156 to a member 157 which is pivotallymounted on the stud 152. Said member 157 provides a brake shoe 158, and when the lever'151 is moved as already described, it causes movement of the member 157 through the medium of a spring 159 surrounding the bolt 155, and this action forces the shoe 158 into contact with the outer periphery of the clutch member 142 and causes the rotating parts, includmg the pulleys 7 and 9 and the spindle 5, to

p. In order that the clutch and brake mechanonrotatable.

nism just described may be operated by hand when desired, the hell crank lever 148 is keyed to its pivot shaft 149, and at the other end of said shaft is keyed a hand lever 160.

As already set forth, the dressing action to dress and true the grinding wheels 25 and 25a is inaugurated from the counting mechanism contained in the casing 52. This counting mechanism can be set to cause the dressing to occur after each grinding operation, or only at the end of a number of grinding operations between one and some high number, for example twenty, depending on the size of ratchet wheel 62. Referring to Figs. 9 and l0,it will be'remembered that the ratchet wheel 62, when the hold pawl 67 releases it and allows the spring to retract it clockwise, comes to a stop when the pin103 carried by said ratchet wheel engages the pin 104 projecting from a cylindrical flange 161 provided by shaft 57. As the position of the ratchet wheel when the hold pawl 67 is moved downwardly to release it is a fixed position, the position of the pin 104, therefore, determines the amount of clockwise rotation of said ratchet wheel, and consequently by adgllasting the position of the pin 104,,thc numr of separate actuations of the wheel by the pawl 61, which will be necessary to again move the cam portion 70 into engagement with the roller 71, can be controlled. This adjustment which determines the number of workpieces that will be ground between successive dressing operations is accomplished in the following manner.

, The cylindrical flange 161 abuts against the right hand journal 162 provided for the shaft 57, and by means of a nut 163 on the front of said shaft, which presses against an inter posed indicator dial164, the flange 161 will then be drawn solidly against the journal portion 162 and the shaft 57 be thus made by rotating the shaft 57, the frontof said shaft being slabbed off to al ow the use of a wrench for this purpose. Since the dial member 164 is keyed to the shaft 57, it will be readily seen that said dial can be graduated to indicate directly the number of interposed grinding operations between successive dressing operations, said dial being read by means of a stationary mark provided on the front of the casing 52.

It will be seen, that once the machine is set for grinding a particular; workpiece a that it functions automatically to grind successive workpieces to the same size provided, of course, that the operator removes the finished workpiece whenever the slide 3 rises and the spindle 5 comes to a stop. The setting of the base 31 determines the slope of the frustoconical surface on the workpiece between the flanges b and 0; this may be conveniently and accurately done by means of a screw shaft 165 chine frame.

By loosening the nut 163, them 104 can be turned to any desired position providing a hand wheel portion, and which engages swivel nuts 166 and 167 which are provided respectively by the machine frame and said base. Similarly, the base 3111 may be adjusted by means of a screw shaft 165a and swivel nuts 166a and 167a, it being remembered that in this case the turret 35 must be rotated in the opposite direction as herein described.

Once the grinding operation-has started,= the cutting edge of-the wheels 25 and 25a will be kept at the same distance and angular position in relation to the workpiecesa, since they are periodically withdrawn and dressed by means of dressing devices 91 and 91a which, once the bases 31 and 31a have been. fastened in position, are fixed upon the ma- By means of,the compensating mechanism described, the grinding wheels are advanced towards these dressing points 91 and 91a, so that at each dressing the wheels will be made tangent to the plane of the dressing diamonds.

It is to be particularly noted, as regards the grinding operation that produces the finished cylindrical or conical surface on each workpiece, that the grinding wheel surface is maintained always in tangential relation to a and an extremely fine finishing cut, are realized,being inherent to the manner in which the work and'wheel are moved into contact. Such movement causes rapid grinding as "soon as contact is made, yet, owing to the vextreme flatness of the angle of approach relative to the surface, there is no shock to the machine parts. The instant the axis of the grinding wheel is on the level of the axis of the workpiece, their centers have reached that position where they will be closest together; they attain such condition, and the grinding is finished when the spring in the machine parts has relaxed. The dwell of'the grinding wheel 25 at its lowest position allows this spring to disappear which it does when the grinding is complete and the wheel is truly tangent to the wprkpiece.

We claim:

1. In a grinding machine, the combination with. a pair of grinding wheels, and a work holding spindle to hold a workpiece to be operated upon simultaneously by said grinding wheels, of means to cause said spindle and said grinding wheels to move, the one relaand retreat substantially parallel to the axis of said spindle so as to undercut a flange on the workpieces.

2. In a grinding machine, a work holding spindle, a vertically reciprocatory slide upon which said spindle is mounted, means to reciprocate said slide vertically allowing it to dwell in one position for the performing of a grinding operation upon the workpiece, means to rotate said spindle, and means to stop the rotation of said spindle and start it again when said spindle is in one extreme position.

3. In a grinding machine, a machine frame, a base angularly adjustable on said machine frame, a reciprocatory table carried by said base, an angularly adjustable turret carried by said table, a cross slide carried by said turret, and a grinding wheel carried by said cross slide.

4. In a grinding machine, a grinding wheel, a work carrying spindle, said parts having an operative position in which the grinding wheel engages a workpiece carried by said spindle, means for moving one of said parts at right angles to the plane containing the centre of the grinding wheel and the axis of the spindle when the grinding wheel is grinding a workpiece to separate the spindle and grinding wheel, a dressing device located substantially in said plane, means for moving said grinding wheel relative to said dressing device to dress and true the former when said spindle and said grinding wheel are separated and for moving saidgrinding wheel back to its original position after the dressing operation, and means for advancing said grinding wheel towards said dressing device between dressing operations to maintain the machine in condition to grind successive workpieces to the same size.

5. In a grinding machine, a grinding wheel, a work carrying spindle, said parts having *anoperative position in which the grinding wheel engages a workpiece carried by said spindle, means for moving one of said parts at right angles to the plane containing the centre of the grinding wheel and the axis of the spindle when the grinding wheel is in engagement with a. workpiece to separate the grinding wheel and spindle, a dressing device located substantially in said plane, means for moving said grinding wheel relative to said dressing device to dress and true the former when said spindle and said grinding wheel are separated, means for causing said last named means to come into operation after a plurality of relative motions of said grinding wheel and spindle at right angles to the said plane, and compensating means for shifting the position of the grinding wheel with respect to the workpiece in between dressing operations to maintain the machine in condition to grind successive workpieces to the same size.

6. In a grinding machine, apair of grinding wheels, a work carrying spindle, said parts having an operative position in which the grinding wheels engage a workpiece, a workpiece carried by said spindle, means for moving said spindle at right angles to the plane containing the centre of one grinding wheel and the axis of the spindle when said grinding wheels are in engagement with a workpiece, to separate said spindle from said wheels, dressing devices located substantially in said plane, means for moving said grinding wheels relative to said dressing devices to dress and true the former when said spindle and said grinding wheels are separated, and means for moving said grinding wheel towards said dressing device between dressing operations to maintain the machine in condition to grind successive workpieces to the same size.

7. In a grinding machine, a pair of grinding wheels, a work carrying spindle, said parts having an operative position in which the grinding wheels engage a workpiece carried by said spindle, means for moving said spindle at right angles to the plane contain" ing the centre of one grinding wheel and the axis of the spindle when the grinding wheel is in engagement with a workpiece, to separate? said spindle from said wheels, dressing devices located substantially in said plane, means for moving said grinding wheels relative to said dressing devices to dress and true the former when said spindle and said wheels are separated, means for causing said last named means to come into operation after a plurality of motions of said spindle at right angles to said plane,'and means for moving the grinding wheel towards the dressing device in between dressing operations to maintain the machine in condition to grind successive workpieces to the same size.

8. In a grinding machine, a work carry ing spindle, a grinding wheel, said parts having an operative position in which the grinding wheel engages a workpiece carried by the spindle, means for moving one of said parts at right anglesto the plane containing the centre of the grinding wheel and the axis of the spindle to separate the grinding wheel and spindle, and means for moving one of said parts substantially in said plane, the aforesaid motions being so synchronized that the grinding wheel may undercut a flange on a workpiece.

9. In a grinding machine, a work carrying spindle, a grinding wheel, said parts having an operative position in which the grinding wheel engages a workpiece carried by the splndle, means for moving one of said parts at right angles to the plane containing the centre of the grinding wheel and the axis of the spindle whenrthe grinding wheel engages a workpiece, a dressing device located substantially in said plane, means for moving said grinding wheel past said dressing device to dress and true said wheel, and means for adjusting the angle between the spindle axis and the axis of the grinding wheel.

10. In a grinding machine, a work carrying spindle, a grinding wheel, said parts having an operative position in which the grinding wheel engages a workpiece carried by the spindle, means for moving one of said parts at right angles to the plane containing the centre of the grinding wheel and the axis of the spindle when the grinding wheel engages a workpiece to separate the grinding wheel and spindle, a dressing device located substantially in said plane, means for moving said grinding wheel parallel to its axis past said dressing device to dress and true said wheel to a cylindrical surface, and means to adjust the angles between the spindle axis and the axis of the grinding wheel.

I 11. In a grinding 1nach1ne,a work carrylng spindle, a grinding wheel, said parts having an operative position in which the grinding wheel engages a workpiece carried by the spindle, means for moving one of said parts at right angles to the plane containing the centre of the grinding wheel and the axis of the spindle when the grinding wheel engages a workpiece to separate the grinding wheel and spindle, a dressing device located substantially in said plane, means for moving said grinding wheel parallel to its axis past said dressing device to dress and true said wheel to a cylindrical surface, and means for varying the angle betweenthe spindle axis and the axis of the grinding wheel without disturbance of the foregoing relations.

12. In a grinding machine, a work carrying spindle, a grinding wheel, said parts having an operative position in which the grinding wheel engages a workpiece carried by the spindle, means for moving one of said parts at right angles to the plane containing the centre of the grinding wheel and the axis of the spindle when the grinding wheel engages a workpiece to separate the grinding wheel and spindle, means to move one of said parts in said plane, the aforesaid motions being so synchronized that thegrinding wheel may undercut a flange on a workpiece, and means for dressing said grinding wheel.

13. In a grinding machine, a work carrying spindle, a grinding wheel, said parts having an operative position in which the grinding wheel engages a workpiece carried by the spindle, means for moving-one of said parts" at right angles to the plane containing the centre of the grinding wheel and the axis of the spindle when the grinding wheel engages a workpiece to separate the grinding wheel and spindle, means to move one of said parts in said plane, the aforesaid motions being so synchronized that the grinding wheel may undercut a flangeon a workpiece, a dressing device substantially in the said plane, and means to move said grinding wheel past said dressing device to dress and true said wheel.

14. In a grinding machine, a work carrying spindle, a grinding wheel, said parts having an operative position in which the grinding wheel engages a workpiece carried by the spindle, means for moving one of said parts at right angles to'the plane containing the centre of the grinding wheel and the axis of the spindle when the grinding wheel engagesw a workpiece to separate the grinding wheel and spindle, means to move one of said parts in said plane, the aforesaid motions being so synchronized that the grinding wheel may undercut a flange on a workpiece, a dressing device substantially in said plane, means to move said grinding wheelpast said dressing device to dress and true said wheel, and means to shift the position of said dressing device in said plane and to change the lineof movement of said grinding wheel, to dress a frusto-conical surface on said wheel, without disturbance of the foregoing relations.

15. In a grinding machine, a work carrying spindle, a grinding wheel, said parts having an operative position in which the grinding wheel engages a workpiece carried by thespindle, means for moving one of said parts at right angles to the plane containing the centre of the grinding wheel and the axis of the spindle when the grinding wheel engages a workpiece to separate the grinding wheel and spindle, means to move one of said parts in said plane, the aforesaid motions being so synchronized that the grinding wheel may undercut a flange on a workpiece, a' dressing device in said plane, means to move said grinding wheel past said dressing device to dress and true said wheel, and means to cause said last named means to be brou ht into op eration only after the grinding of a predetermined number of workpieces.

16. Ina grindin machine, a work carrying spindle, a grin ing wheel,'sa-id parts having an operative position in which the inding wheelengages a workpiece carried y the spindle, meansi for moving one of said parts grinding wheel past said dressing device to dress and true said wheel, means to shift the position of said dressing device in sald plane and to change the line of movement of said grinding wheel, to dress a frusto-conical surace on said wheel without disturbance of the foregoing relations, and means to cause said last named means to be brought 1nto operation only after the grinding of a predetermined number of workpieces.

17. In a grinding machine, agrinding wheel, a work carrying spindle, said parts havin an operative position in which the grinding wheel engages a workpiece carried by said spindle, means for moving one of said parts to separate said grinding wheel and spindle, and return them into engagement again, a dressing device, means for causing relative motion between said dressing device and said grinding wheel to dress and true said wheel, said relative motion being at right angles to the movement of separation between said grinding wheel and said spindle, and means to cause said last named means to come into operation only after the grinding of a predetermined plurality of workpieces.

18. In a grinding machine, a grinding wheel, a work carrying spindle, said parts having anoperative position in which the grinding wheel engages a workpiece carried by said spindle, means for movingone of said parts to separate'said grinding wheel and spindle, and return them into engagement again, a dressing device, means for causing relative motion between said dressing device and grinding wheel to dress and true said wheel, said relative motion being at right 3'5 angles to the movement of separation between said grinding wheel and said spindle, and means brought into operation by the aforesaid relativemotion etween the grinding wheel and the dressing device to temporarily suspend the operation of the means for returning said grinding wheel and spindle.

19. In a grinding machine, a grinding wheel, a work carrying spindle, said parts having an operative position in which the grinding wheel engages a workpiece carried by said spindle, meansfor moving one of said parts to separate said grinding wheel and .spindle and return them into engagement again, a dressing device, means for causing relative'motion between said dressing device and grinding wheel to dress and true said wheel, said relative motion being at right angles to the movement of separation between said grinding wheeland said spindle, means to cause said last named means to come into operation only after the grinding of a predetermined plurality of work ieces, and means brought into operation by t e aforesaid relative motion between the grinding wheel and the dressing device to temporarily suspend the operation of the means for returning said grinding wheel and spindle.

20. In a grinding machine, a pair of grinding wheels, a pair of dressing devices, a pair of tables mounted for rectilinear movement and each one carrying one of the aforesaid parts, a counting mechanism actuated periodically in the grinding of a plurality of workpieces, a piston and cylinder unit for each table, a valve controlled by said counting mechanism adapted in one position to admit fluid to both of said cylinders at given sides thereof, and in the other position to admit fluid to the other sides of said cylinders, fluid pressure lines connecting said valve to said cylinders, a third piston and cylinder unit to return the counting mechanism to original position, a valve in one of said lines to divert the fluid from one end of one table actuating cylinder to the third cylinder, and means carried by one table to actuate said last named valve.

21. In a grinding machine, a air of grinding wheels, a pair of dressing devices, a pair of tables mounted for rectilinear movement and each one carrying one of the aforesaid parts, a counting'meohanism actuated riodically in the grinding of a plurality 0 work pieces, a piston and cylinder unit for each table, a valve controlled by said counting mechanism adapted in one position to admit fluid to both said cylinders at given sides thereof, and in the other position to admit fluid to the other sides of said cylinders, a branching fluid pressure line connecting said valve to said 0 linders at given sides thereof, a branching uid pressure line connecting said valve to said cylinders at the other sides thereof, a third piston and cylinder unit to return. the counting mechanism to original position, a valve in one of the branches to divert the fluid from one end of one table actuating cylinder to the third cylinder and means carried by the other table to move said last named valve.

22. In a grinding machine, a grinding wheel, journal bearings for said grinding wheel allowing it to rotate, a table carrying said grinding wheel bearings, a dressing device, fluid pressure means to actuate said table to move said grinding wheel past said dressing device to dress and true the same and return it to the initial grinding position, a positive stop locating the said grinding position, and an automatic valve to cause said table to be stopped, gradually to prevent injury to said bearings.

23. In a grinding machine, a grinding wheel, journal bearings for said grinding wheel allowing it to rotate, a table carrying said grinding wheel bearings, a piston and cylinder unit connected to said table, a positive stop locating the grinding position of said grinding wheel, fluid pressure means set in operation acting on said piston and cylinder unit to move said table to carry the grinding wheel away from the grinding po sition, means to cause the pressure fluid to act on said piston and cylinder unit to return said table where it is located and held in the grinding position by said stop, and valve means operated by said table as it moves the grinding wheel away from the grinding posaid table without shock.

24:. In a grinding machine for the finishing of successively-presented similar work pieces to the same size, a rotary grinding wheel, a rotary workholding spindle, means for imparting rectilinear motion to said spindle, substantially at right angles to its axis, to carry a workpiece thereon into grinding contact with said wheel, while maintaining said spindle axis at a constant distance from a plane which is parallel to said recti- V linearmotion and tangent to the cutting locus ing the spindle axis at a constant distance from a plane which is parallel to said rectilinear motion and tangent to the cutting locus of said wheel, means for returning said spindle, following each such grinding contact, to non-grinding position, for removal of the ground workpiece therefrom, and means opertill able on said wheel while said spindle is in non-grinding position, to restore the tangential relation between said plane and the surface of said wheel.

26. In a grinding machine for the finishing X of successively-presented similar workpieces to the same size, a rotary grinding wheel, a

rotary workholding spindle, means for imiparting rectilinear motion to one of said parts, substantially at right angles to the spindle axis, to produce grinding contact between said wheel and a workpiece on said spindle, while maintaining the spindle axis at a constant distance from a plane which is parallel to said rectilinear motion and tangent to the cutting locus, ofsaid wheel, means for proto non-grinding position, to permit removal of a workpiece from said spindle, a cross feed mechanism operable on said wheel during the dwell of said parts in non-grinding position, and a dressing device, located in said plane, to which said wheel is subjected following the 0 eration of said cross feed mechanism, there y to maintain the cutting locus of said wheel in tangential relation to said plane. I

point. curing by said motion the/return of said parts 27. In a grinding inachine for the finishing of successively-presented similar workpieces to the same size, a rotary grinding wheel, a rotary workholding spindle, means for imparting rectilinear motion to said spindle, substantially at right angles to its axis V to carry a workpiece thereon into-grinding contact with said wheel, while maintaining said spindle axis at a constant-distance from a plane which is parallel to said rectilinear motion and tangent to the cutting locus of said wheel, means operable on the return of said spindle by said motion to non-grinding position for restoring the tangential relation etween said plane and the surface of said wheel, a second rotary grinding wheel for operation radially on'a flange of each workpiece, and means for moving said second wheel in timed relation to the approach to and retraction from grinding position of said spindle. 5 a

28. In a grinding machine for the finishing of successively-presented similar workpieces to the same size, a rotary grinding wheel, a rotary workholding spindle, means for imparting rectilinear motion to one of said parts, substantially at right angles to the spindle axis, to produce grinding contact be-- 5 tween said wheel and a workpiece on said spindle, while maintaining the spindle axis at a constant distance from a plane which is parallel to said rectilinear motion and tangent to the cutting locus of said wheel, means or procuring by said motion the return of said parts to. non-grinding position, to permit removal of a workpiece from said spindle, a cross feed mechanism operable on said wheel during the dwell of said parts in nongrinding position, a dressing device in said plane, and automatic means for subjecting said wheel, after each cross feeding operation, to the action of said dressing device.

29. In a grinding machine, the combination with a grinding member, a work-holding member, a table or carriage for one ofsaid members, and fluid pressure means to move said table or carriage, of a mechanically operated carriage or slide for the other'of said members, means to set said fluid pressure means in operation, and means controlled by the movement of the table or carriage and operated thereby to stop the movement of the carriage or slide eta predetermined desired 30. In a grinding machine, the combination with a grinding wheel, a dressing device, a table or carriage carrying one of said parts, and fluid pressure means to move it thus to dress said grinding wheel, of a mechanically operated carriage or slide adapted to move a workpiece in relation to said grinding wheel, and control means to cause the mechanically operated slide to reciprocate a plurality of times, to then cause the table or carriage to reciprocate once, preventing the mechanically moved slide from moving beyond a desired point, and finally causing resumption of movement of the mechanically operated slide after the fluid pressure moved carriage has ceased its operation.

- ROGER Na HEALD.

EDWARD M. TAYLOR. RALPH A. QUIMBY.

CABLE J. HIGHBERG.

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