US1605146A - Grinding machine - Google Patents

Description

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'7 Sheets-Sheet l w. A SCHMIDT GRINDING MACHINE Filed sept. 1e

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W. A. SCHMIDT A V GRINIQINGV MACHINE- v Filed Sept. 16, 1921 7 Sheets-Sheet 4 y @man1/Lkw u @Hof/vlug' /yw im 1,605,146 W. A. SCHMIDT GRINDING MACHINE 1921 7 Sheets-Sheet 5 Filed Sept 16 Nov. 2 1926.

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W. A. SCHMIDT GRINDING MAHINE vFiled sept. 1e

1921 7 Sheets-Sheet 6` Patented Nov. 2, 1926.

PATENT OFFICE. l

WILHELM A. SCIFMIDT, OF ILION, NEW YORK, ASSIGNOR TO AREMINGTON TYPEWRITER COMPANY,` OF ILION, NEW YORK, A CORPORATION OF NEW YORK.

GRINDING MACHINE.

` Application filed september 1e, 1921. sensi no. 501,151. K

My inventionrelates to machines for simultaneously grinding opposite faces of an article interposed between a pair of grinding wheels. y y

Generally stated, one of the main objects of the invention is to provide a highly efficient machine of the character specified.

` More specically stated;=the objects of the invention may be said to be as follows 1st. To so mount the oppositely arranged grinding wheels that the aXes thereof may be disposed out of alignment, and provide not only for grinding the article. but to enable the grinding wheels to be effectively dressed, one by the other.

2nd. The provision of an leflicient work holder which has a freedom of movement in certain directions and is controlled or restrained in its movementin such direction by the directaction of the grinding faces of the wheels on the article supported by said holder'.

3rd. The provision of efficient mounting means for the grinding wheels so that they may be moved relatively towards and away from one another and the grinding may be effected with great precision.

lith. The provision of efficient means for controlling the relative movements of the grinding wheels in the grinding and dressing operations.

5th. The provision of efiicient and accurate gaging means for the wheels in both the grinding and dressing operations.

th. The provision of comparatively simple, reliable and efficient automatically operating means for controlling the cycle of operations effected in grinding an article.

7th. The provision of single and effective means for bringing a` supply of liquid to the grinding wheels.

8th. The provision of simple and effective means for preventing injury or breakage in the power transmitting means and assuring a proper and accurate grinding operation.

9th. The provision of an automatic control of the work holder without interfering with the floating character thereof.

10th. The provision of various details of construction which contribute to the production of an accurate and highly efficient grinding machine. I

To the above and other ends which will hereinafter appear, my invention consists in al view of the upper portion of the machine taken on the line 3-3 of Figure 1 and lookng in the` direction of the arrows at said ine.

Figure 4 is a corresponding detail sectional view of thelower portion of the machine with parts omitted, the view illustrating the cam and connections for the fioating work holder..

Figure 5 is a detail fragmentary vertical sectional view taken centrally through the right-hand spindle-carrying head on the line 5 5 of Fig. 2 and looking in the direction of the arrow at said line.

Figure 6 is a fragmetary detail horizontal sectional view of the stop means for limiting the relative movement of the heads towards each other in the grinding operation, the section being taken on the line 6 6 of Figure l. and looking in the direction of the karrow at said line.

Figure 7 is a detail transverse sectional view of the. grinding wheels showing the manner of mounting the same on their4 respective spindles.

Figure 8 is a detail fragmentary fore-andaft vertical sectional view showing the cam and connections for moving the right-hand grinding wheel axially, the section being taken on the line 8-8 of Fig. l and looking in the direction of the arrow at said line.

' Figure 9 is a fragmentary detail side elevation with parts broken away and showing a portion of the work holder with an article clamped in place. f

Figure 10 is a detail transverse sectional view of the same taken on the line 10-1() of Figure 9 and looking in the direction of the arrow at lsaid line.

Figure l1 is -a'detail transverse sectional view of the same taken on the line lll-11 of Figure 9 and looking in the direction of the arrow at said line.

Figure l2 is a fragmentary detail vertical transverse sectional view, with parts omitted, of a portion of the work holder, the view being' taken on the line 12,-12 of Figure 3 and looking in the direc-tion of the arrow at said line.

Figure 13 is a detail top plan view of the frame, which supports the'floating work holding devices.

Figure 14 is a detail fragmentary rear elevation of one of the work holding devices with a type bar secured in place therein.

Figurel is a detail diagrammatic view looking endwise of thefs'pindles of the grinding wheelsand showing the.l relative disposition of the twobppositely disposed grindingwheels with the axes thereof out, 0f alignment.` v`

' Figures 16 and 17 are diagrammatic front elevations of a `workholdingdevice with a type` bar secured thereto, the views showing respectively, and very much exaggerated, dtferent :parallel and angular positions a work holding device and the type bar carried thereby -may assume, as the parts are viewed from the front of the machine.

Figure 1S is a likeview of the same showing different angular positions the parts may assume as viewed from above.v

My invention is shown, inthe present instance, embodied in a machineV designed to simultaneously grind the opposite' parallel. fiat bearingiface's on the heel or pivot-end portion of 'a sheet metal type bar intended to be received in a bearing slot of 'a type bar segment of a typewriting machine. It should be understood,ihowever, thatA the invention is notrestricted to its embodiment in such a machine andthat the machine shown may be 'employed wherever found available. I contemplate embodying features of vmy invention in ltwo formsv of machines, one a so-called hand machine in which the various operations are controlled by hand, and the other asd-called automatic machine in which a complete cycle of operations in grinding a type bar is automatically effected; f l

I will first describe the automatic machine, and will then refer to vthe hand machine indicating' wherein the automatically controlled parts of the first described machine are orf may be arranged to'be controlled byl hand,y

It sliould be borne in mind that in` grinding opposite bearing faces of each type bar it is essential that the faces be ground in true parallelism to accurately co-act with thebcaring'walls of the slot in the segment in whichthe type bar is received and pivoted. It also is essential that the grinding at each side of the bar be only to a given depth so that the thickness of the bar at this point will be reduced from, say, .035 of an inch to, say, .03e of an inch, and will properly fit within its guide slot and coact properly with the side walls thereof. Vilith a consideration in mind ofthe great requiredl in grinding the articles it will be understood how necessary it is to provide efficient means for mounting the grinding wheels and work holder and for controlling and gaging the movements thereof and for accurately bringing about an laction ofthe grinding wheels on the work.

is shown in the present instance the machine may be said to comprise two oppositely disposed cup-shaped grinding wheels mounted on spindles or shafts arranged end to` end andout of alignment, and movable axially relatively one to the other to effect a relative movement. of the wheels towards and away from one another into and out of grinding position with reference to the article to be ground, and also into and out of co-'action with each other to effect a dressing of the grinding faces'of the two wheels one on the other. :A floating work holder carries a type bar to be ground between opposing parallel faces of the grinding wheels and maintains it in such position during the grinding operations. lfowever, the construction and mounting of the holder is such that the type bar has a freedom of movement axially of the shafts on which the vf'hce'ls are mounted and at various angles to the shafts, and is controlled and restrained in such movements only by the direct contactl of the article to be ground with the parallel grinding faces of the wheels. llVhen, therefore, the 'wheels are brought towards each other the interposed floating type bar is'automatically brought into proper parallelism with the faces of the grinding wheels by the direct action of said faces of the wheels themselves on the type bar, and the grinding action isv .properly applied and equally distributed in parallelism on both sides of the type bar. As will hereinafter appear, means are provided for controlling the movement of the work holder,`with the work supported thereby, into and out of operative position, and for contr lling the relative axial movements of the wheels into and out of grinding position, and for gaging the movements of. the wheels against the work,

As shown in` the present instance, the frame l of the machine which supports various working parts, has a bed 2 formed with longitudinally extending ways 3 on which spindle carrying heads 4 and 5 are mounted for adjustment towards and from each other. A screw 6 turns'in a bearing in a bracket 7 secured by screws 8 to the righthand Yend of the bed The threaded portion of-this screw is received in a tapped opening` in the head 4 and controls the adjustment ot the latter along the ways 3. The adjustment ot the lett-hand head 5 is controlled in a like manner by a 'correspending screw 10.

Referring particularly to Fig. 5, it will be seen that the driving spindle or shaft 11 of the right-hand grinding wheel 12 turns in adjustable bearings contained within a quill or hollow supporting member 13 that is mounted for independent longitudinal movement in the right-hand supporting head 4 and constitutes an oil containing chamber in which the spindle turns.4 The head 4 carries two two-part surrounding supports tor the quill 13, each comprising a section 14 held to its companion member 15 by screws 16. An oil chamber 17 is formed in each member 14, access being had thereto through an oil opening 18 ordinarily closed by a screw plug 20. The quill 13 is prevented from turning in its bearing in the head 4 by a spline 21 received in a spline groove 22 that enables the quill 13, nevertheless, to receive bodily longitudinal movement with the parts carried thereby independently ot the supporting head 4. An oil opening that is normally closed by a screw 23 leads to the interior oll the quill, and through this opening oil may be introduced to about one-halt the height of the quill so that that portion ot the spindle 11 contained in the quill may turn in a bath of oil. Suitable bearings 24 within the quill receive and support the spindle 11 and are provided with inclined outer surfaces surrounded by members 25 having corresponding co-acting inner inclined surfaces. An adjustable collar 26 has a threaded connection with a companion member 25 to effect an adjustment of the latter and thereby adjust the associated member 24. An end plate or head 27 centrally apertured for the passage ot the spindle 11 therethrough, is secured to the rightshand end of the quill 13 by screws 28. An end plate orhead 30 is secured by screws 31 to the lett-hand end of the quill, and is provided with a thrust bearing 32 which coacts with a flange 33 on the spindle. Contained within the quill 13, and loosely surrounding the spindle 11,A is a flanged collar 34 that bears against a part 35 lixedlyY secured to the quill. A coiled expansion spring 36 surrounds the spindle and bears at one end against the flanged collar 34, and at its opposite end againsta lianged collar 37 that loosely surrounds the spindle. The right-hand face of the collar 37 bears against anti-friction balls 38, which in turn bear against a flanged collar 4() that surrounds the spindle and is secured thereto by a screw 41. The balls 38 are received in a ball spacer 42 that is free on the shaft. rlhe etlect off this construction is to exert the torce of the spring 36 through the anti friction balls against the spindle tending to torce the latter longitudinally to the right in its bearings and to maintain the flange 33 on the spindle against the thrust bearing 32.

The inner end portion of the spindle 11 is, as best shown in Figu7, formed with a seat for a key 44 which connects a disk 45 to turn with the spindle. One side of the disk bears against the flange 33 on the shaft, whereas one side of the cup-.shaped grinding wheel 12 bears against the opposite tace of the disk. The spindle is slotted longitudinally at 43 toreceive a spline projection 47 of a centrally apertured disk 43, to ixedly connect the latter to turn with the spindle.

This disk 48 bears against the" opposite side of the wheel`12 and is clamp-ed in. place by a disk 50 having a tapped central opening by which it may be screwed into place on the threaded end 51 oit the spindle, and thus lirmly hold the wheel 12 on its driving spindle. Rotation is transmitted to the right-hand grinding wheel 12 by a pulley 52 supported on'the head 4 independently of the spindle 11 but operatively connected to the spindle so as to cause the latter to turn with the pulley but enable the spindle to move longitudinally with the quill 13 independently ot the pulley. Thus the pulley 52 is mounted on bearing balls 53 through bearing members 54 on the pulley. Bearing members '55 on which the balls roll are supported on a liange supporting sleeve 56 secured to a bracket 57 on the head 4 by screws 58, screws 59 connecting the bracket 57 to the head. A centrally apertured end plate or disk 30 tits over the supporting sleeve 56, and has a projection 61 that is received in a longitudinally extending groove 62 in the bearing sleeve so as to prevent the plate from turning on the supporting sleeve. A lock nut 63 is screwed onto the threaded end 64 of the supporting sleeve 5G and retains the pulley against removal therefrom. An oil opening 65 in the pulley, normally closed by a screw 66, communicates with the bearings oLt the pulley on its fixed support. A connecting member G7 is keyed to the outer reduced end portion of the spindle 11 and is held in place thereon Iby a nut 68. This member 67 comprises two arms' that extend in opposite directions trom the spindle and are received at the free ends thereof in grooves, ways or slots 70 formed in the in-A is not transmitted to the spindle 11, or exerted thereon transversely of its axis.

F rom certain aspects of my invention any suitable means whether hand actuated or automatically operating, may be employed to move the quill 13 and the parts carried thereby axially to move the grinding wheel 12 towards and away from its companion grinding wheel. In the present instance l have illustrated, as shown in F ig. 5, a sleeve 72 which is slit at 73 to form to a clamping member in the nature of a split ring or cylinder'. This member surrounds the quill intermediate the two sets of supports 14 and 15 and is clamped tight on the quill by screws 74;. rlhese screws pass freely through openings in a flange 75 that projects rearwardly from the sleeve 72 above the split 73 therein, and engage in threaded openings in a corresponding flange 7 6 below the slit 73. The underside of the sleeve is formed with a recess in which is seated two bearing blocks 77 held in place by screws 78. These bearing` blocks co-act with the upper rounded end of a crank arm 80 secured to a rock' shaft 81 extending fore-andaft from front to rear of the machine and mounted in bearings in the head 4. The forward end of. this shaft is squared, as indicated at 82 in. Figs. 1 and 2, to receive a land manipulated crank not shown), should it be desired to control the axial movement of the spindle 11 b v hand. However, in the present instance I have provided means for automatically controlling the rock shaft 81, quill 13 and the axial movement of the spindle 11 and grinding` wheel 12 carried thereby, as will hereinafter clearly appear.

It is unnecessary to move both of the grinding wheels axially towards and away from each other in order to obtain an eifective grinding of opposite parallel faces of the article to be ground, or in order to dress the grinding faces of the wheels one by the other. Therefore, it is unnecessary to provide an axially movable quill for the spindle 83 of the left-hand grinding wheel 84, the latter remaining fixed against axial movement on its head 5. However, aside from the fact that the quill of the right-hand head l is movable axially, whereas the lefthand quill 13a is held fixed on its head5, and has no means connected therewith for moving it and the parts carried thereby axially, the bearings for both spindles and the driving` connections with their pulleys, etc., are substantially identical. .A detailed illustration and description of the mounting for the left-hand wheel would amount practically to a repetition of that already given, and' it is therefore deemed unnecessary. Where corresponding parts are shown at both sides of the machine, they will be indicated by corresponding reference numerals.

rlhere is one important point to be observed, however. s the machine is shown in the present instance, the two spindles 11 and 83 are arranged end to end but are maintained out of axial alignment, their axes being parallel and arranged one above the other, so that the grinding wheels 12 and l841 are eccentrically arranged with reference to each other, asindicated in Fig 15. This arrangement is of importance in dressing, truing or facing the wheels by their mutual action one on the other, as will be hereinafter more fully brought out, but is unimportant so far as the grinding operation is concerned. For the latter purpose it is immaterial whether the spindles 11 and 83 are arranged end to end in alignment or are arranged with their axes parallel as shown. Therefore a machine may be so constructed that the axes of the spindles 11 and 83 are held in alignment for the grinding operation but may be shifted laterally relatively one to another to bring their axes in parallel arrangement and held in such arrangement during the truing or dressing operation.

The means shown in the present instance for automatically moving the roclr shaft 81 and thus controlling the relative axial movements between the grinding wheels 12 and 8st comprises an angular lever, designated as a whole by the reference numeral 85 and best shown in Figs. 1 and 2. This lever is pivoted to turn freely on the rear end portion of the rock shaft 81 and is provided with a yokelilre depending' arm 86 carrying oppositely disposed set screws 87 with lock nuts 88 thereon. Fixedly, though detachably secured to the rock shaft 81 is a hub 90 provided with a bifurcated extension 91 in which is fitted the upper end of a resilient member or spring arm or plate 92 that is secured in place between the arms of the bifurcated extension by screws 93. The lower free end of this spring arm 92 eirtends down between the set screws 87. The construction is such that the only connection between said arm 86 and the rock shaft 81, by which motion is transmitted from the former to the latter, is through the set screws 87 bearing on the spring arm 92, and the purpose of which will hereinafter more clearly appear'. The horizontally disposed arm of the bell crank lever 85 is pivotally connected to a depending link 941. The low-r end of this linlr 94 is in turn p'ivotally united to aroclring arm 95, as is best shown in Fig. 8. The arm 95 is pivoted at 90 to the frame 1 of the machine and has a forwardly projecting member or arm 97 which carries a laterally projecting anti-friction roller 98 atthe free end thereof. This roller is received in a cam groove 100 in one side of a cani wheel 101 lixedly mounted on cam shaft 102. The cam shaft 102 is mounted in suitable bearings in the frame of the machine iii? and extends transversely thereof beyond the right-hand side of the frame where a worm wheel 103 is secured thereto. The worm wheel meshes with a worm 104 on a shaft 105 mounted in bearings in a frame 106. This frame is pivoted at 107 (Fig. 2) to afford a bodilyv lateral movement of the worm shaft around the pivot 107 in order to throw the worm 104 into and out of mesh with the worm wheel 103. "The rear end portion of the worm shaft 105 has a bevel gear 108 secured thereto and this gear meshes with al bevel gear 109 mounted on one end of a short shaft 110 which turns in a bearing supported by the pivoted frame 106. The inner end of the shaft 110 has a driving pulley 111 mounted thereon, as indicated in Fig. 1. A suitably driven belt 112 is received on and coacts with the pulley 111 to turn the cam shaft 102 through the intermediate train of gea-ring, and thereby effects a back and forth axial movement of the quill 13 and the parts carried thereby through the connection betweeen the rock shaft 81 and the cam wheel 101.

Means are provided for automatically throwing the machine out of operation after it has completed a cycle of operations required to introduce a type bar in place, grind it and remove the ground bar. This involves the throwing out of operation of the cam shaft 102, so as to arrest the movements of thev parts by which axial movements of the right-hand grinding wheel 12 is eected. In order to bring this about I have provided a cam 113 on the outer face of the worm wheel 103. This cam coacts with a roller 114 carried by an arm 115 secured to a rock shaft 116. This shaft is mounted in suitable bearings on the right-hand end of the frame 1 and carries a depending arm 117 provided at its lower end with an angular cut-out 118, as shown in Fig. 1, to receive an angular portion 1.20 at the forward end of the worm shaft 105. When the arm 117 is in the position shown in Figs. 1 and 2, the worm shaft will be supported in its elevated position, maintaining the worm 104 in engagement with the worm wheel 103 and rendering effectivethe operative connections from the pulley 111 to the quill 13 which carries the axially movable right-hand driving spindle 11.. The hub of the arm117 has an upwardly extending projection 121 which coacts with a plunger 122 pressed outwardly by a spring 123 contained within a guide sleeve 124 in which the plunger is received and works and which is iixed to the frame 1 of the machine. The force thus exerted by the spring 123 tends to maintain the arm 117 in a position where it will engage the shaft 105 and maintain the pivoted supportingy frame elevated with the worm and worm wheel in mesh. Vhen, however, the cam 113 reaches the roller 114, the lower end of the arm 115 is moved to the right, thus rocking the shaft -116 and withdrawing the lower hoolclike end portion of thearm 117 from beneath the shaft 105. The frame 106 is then free to turn around its pivot 107, lowering the worm 104 and disengaging it fromr the worm wheel, thus automatically disconnecting the operating means for the cam shaft 102 and arresting the axial movement of the right-hand grinding wheel.

The extent of this disengaging movement of the worm, through the pivotal movement of the frame 106, is limited and determined by a link 124 pivoted at its lower end,'at 125, to the frame 106, and at its upper end, as at 126, to a lever 127 provided at its forward end with a handle 128 by which it may be controlled. This lever is pivoted to the frame of the machine at 130 and the downward movement at the rear end thereof is limited by a set screw 131 carried thereby and coacting with the stop pin 132, carried by frame 1. In'order to reestablish the driving` connection between the worm shaft 105 and the cam shaft 102, it is merely necessary to depress the handle 128, thereby turning the frame 106 on its pivot 107 and elevating the worm 104 into mesh with its worm wheel 103. At this time the hoo-k like lower end of the arm 117 will engage beneath the forward end of the worm shaft and lock it in its elevated position until a complete cycle of operations has taken place, when the cam 113 will again be effective to automatically disengage the arm 117 and enable the worm to be disengaged from the worm wheel, and an arrest of the cam shaft to be eifected.

I provide meansY for limiting the axial movement of the right-hand grinding wheel 12 into grinding relation with the type bar and towards the wheel 84, and thus accurately determine the depth of the grinding operation and the thickness to which the article is ground. For this purpose I provide gage or stop devices which are best shown in Figs. 1, 2 and 6. The devices4 in question co-mprisea so-called interponent or stop 133 that corresponds in thickness to the thickness of the article after the grinding operation has been effected. This interponent in the presentV instance is shown mounted on a sup-porting member 134. The member 134 has a cylindrical stem 135 seated in a bearing 136 on the head 4 to turn on a horizontal axis, so that the interponent 133 in turning with the member 134 may be shifted into or4 out of operative position. A thumb screw 137 is seated in a tapped opening in the bearing` 136 and is adapted to bear at its end against the cylindrical stem 135 and hold the device 134 in either its operative or inoperative position, as de-r sired. When the device 134 is turned down to operative position1 illustrated in Figs.

1 and f2, the part 133 will be interposed between two stop members 138 and 140. Reterring more particularly to Fig. 6, it will be seen that the stop member 138 has a reduced end portion 141 by which it may be detachably seated in an opening 142 in the head4, whereas the stop 140 is 'formed as the inner end ot a` micrometer screw 143 received inA tapped openings in torwardly projecting flanges 144 and 145 or" the member 72 which is secured to the quill 13. The head ot the micrometer screw is provided .with indices, as indicated at 143, for cooperation with a relatively lined pointer 147, whereas a lock nut 148 secures the screw and its stopy 140 in adjusted position. iii/Tl en the device 134 is in the operative position, with its member 133interposed between the stops 13S and 140, the extent ot movement et the quill 13, with the parts carried thereby, will be limited in theapproach of the grinding wheel 12 towards its companion grinding wheel 84, thus determining` the extent Aor depth of the grinding operation, which may be varied b`y an adjustment of the microme `eter screw 143. 1t has hereinl'ietore been pointed out that the axial movement of'` the right-hand grinding wheel 12 is transmitted throughI the resilient member 92, and it should4 be understood that the parts are so adjusted, constructed and arranged that prior tothe arrest .of the axial movement ot' the grinding wheel 12 4by the stops 133, 138 and 140, the resilient member 92will be flexed, exerting its torce to hold the stops in contact and to lpress the grinding l'ace of the wheel 12 against the article to be ground. it willthus be understood that when the stops 133, 138` and 140 coact to arrest the axial movement of the right-hand driving wheel 12, the force' of the positively actuated connections from the cam 101 is efr- ,erted through the resilient .member 92, and there is an assurance ot' the proper extent ot axial movement of: the wheel, witbout at the same time there Ybeing any liability ot injuring the construction. or the lack ot (proper. extent oil movement due to wear on the parts orlooseness in the connect-ions, etc. When it is desire(q .to dress Vor face the wheels one byI another, it is merely necessary tri-turnthemember .34 out or operative position where its part 133 is interposed bejtween, the stops 138 4and 1*-1-0, thus enabling the. grinding faces met the. wheels to be brought into Contact witheach other. The stops 13S and 140 at this time limit the aiial movement of the wheel 12 towards the wheel l8:1but an adjustment of the stop Y140 en,- ables the extent of this movement to be variedat will'. v l o ,By arranging the .axes lof the wheels out of alignment in the manner shown and described, itwill be understood that every point on the grinding face a of the Wheel 12 will cut crosswise at every point on the grinding face a of the wheel S4, and vice versa, as will be clearly understood from a consideration of Fig. 15. 1t is therefore possible to effectively dress the grinding races oi the wheels one by another, and to dress or true the faces of the wheels accurately and in parallelism.

I will now `describe the floating work holder by which the articles to be ground may be automatically interposed between the grinding wheels; may be moved baclr and ttorth during grinding Operation; and may be removed froml between the grinding wheels after the article is ground.

Referring more particularly to Figs. 1, 2 and 3 and 9 to 14, inclusive, it will be seen thata type bar A., or other article to be ground, is adapted to be seated in a grooved seat 149 in one side ot a work holding device 150. The article is clamped in place in its seat by a clamp or Contact device 151 lixed by its hub to a cylindrical stem 152 which is adapted to slide lengthwise in a bearing 153 inthe member 150 as the contact device 151 moves into and out of clamping engagement with the article to beground. The hub ot the clamp is also mounted to .slide in a bearing 153a in the holding device. The stem 152 projects through to a point at the op positeside yof the device 150,. and at its end portion is formed rectangular in cross-section, as indicated at 154. This rectangular end portion extends through a corresponding opening in a bowed or arched spring' 155 formed `as indicated in Figs. 10 and 14, sothat the central portion of the spring is flat while the free end portions thereof are bent so as to bear against one side ot the work holding device 150. A pin 155"L projecting from a side of the holding device passes through an opening in the spring 155 and prevents it and the clamping member from turning. A hand actuated controlling member 156 is pivoted at 157 to the rectangular portion of the stem, the free end ol2 the controlling member 156 constituting a linger piece by which it may be moved on its pivot 157 from the full to the dotted line position indicated in Fig. 14, or vice versa. rFhe controlling member 156 is in the nature of a lever formed with a cam or enlargement 158,. 1t will be seen that the distance vtrom the pivot 157 tothe flat end portion 100 of the controlling member is considerably less than the ldistance from said pivot 157 to the flat .face 161 of said member. 1n consequence of this, a movement of the controlling member 'from the dotted to the itull line position in Fig. 14, is elleetive to flex the spring 155 and cause the force of the spring to be exerted vlongitudinally of the stem 152, and tov be applied through the contact 151 to the typegbar, .in order to clampl the latter in place vin its seat. 1t will be understood moreover,

that when the flat face 161 of the controlling member engages the spring as shown in full lines. said controlling member` and the parts controlled thereby will be locked or maintained in the position shown, to clamp the type bar to the holder under the force of the spring 155. When, however, the controlling member 156 is turned to the dotted line position the force of the spring 155 on the clamp is released, enabling the latter to be shifted longitudinally of its stem 152 to release the type bar and permit its removal from the holder. If desired suitable auxiliary means may be employed to aid in properly positioning and holding the type bar in place on the holder,such means for eX- ample as a sheet metal bracket 162 secured to the upper edge of the holder by screws 163 and adapted to engage in a recess 164 formed in the type bar. 4

In the present instance I employ two of these work holders 150 constructed and mounted alike and the description of one applies to the other. Each work holder 150 provided with a depending stem, support or carrier 165 by which it may be mounted to receive a pivotal movement around a substantially vertical axis when a type bar is in the operative position shown in Fig. 3. Thus, upstanding coned pivots 166 connect each work holding device 15G-f 165'to an arm, support or carrier 167, whereas stops 168 on opposite sides of each member 165 coact with stop faces 170 on the associated arm 167 to limit the rotative movement of the member 15G- 165 around its pivots 166. This movement of each work holding device 15(1165 around the pivots 166 I have attempted to illustrate in Fig. 18. rl`his view is intended to represent the parts as they are seen when viewed from above the work holding device, although the extent oit' movement is shown greatly exaggerated 'in order to clearly indicate that by this angular movement the plane of the heel b of the type bar to be ground may assume different angles relatively to the axes of the grinding wheels, for purposes which will hereinafter more clearlyr appear. vEach supporting arm 167 is supported by pivots 171, the axes of which are at `right angles to the axes of the pivots 166 and connect the arm 167 to a depending link, support or carrier 172 supported by pivots 173, the axes of which are parallel with the axes ofthe pivots 171. The pivots 173 connect the link 172 with an arm or support, or carrier 174 of a frame, or head designated as a whole by the reference numeral 175 and pivoted on a spindle 176 to an upright primary or main support, or carrying arm 177, which may, if desired, be provided with a handle 178. It will be observed that the supporting frame'or head 175 is provided with two arms 174 arranged at right angles to eachother, asindicated in Fig.f13, and each arm supports a link 172, an arm 167 and a work holding device 150-165 Each arm 174 is provided with a depending lug or stop 179 (see Figs. 3 and 12) that is received between two lugs or stops 180 on the associated link 172. The lower end of each link is likewise provided with two lugs or stops 181 between which is received a stop or lug 182 which projects upwardly from the associated arm r167. The stops 1797and 180 limit the pivotal movement of the associated link 172 around its pivots 173, whereas the lugs or stops 181 and 182 limit the pivotal movement of the arm 167 around the pivots 171 which connect said arm with its link 172. This manner of pivoting a work holding device on a supporting arm 174 enables said device to assume the different positions to bring the heel of the type bar into different parallel planes which I have attempted to represent in Fig, 16. .In this figure the parts appear as seen from the front of the machine although it will` be understood that the diagrammatic showing represented greatly exaggerates the extent of movements permitted. In Fig. 17 the diagrammatic showing is intended to represent the movement of a work holder around its supporting arm 174 on the pivots 173, or on the pivots 173 and 171 to such a position as to present the heel of the type bar at different angles with reference to the parallel grinding faces of the grinding wheels. This view represents the parts as they would appear when seen from the front of the machine, -although it will be understood that, as in Figs. 16 and 18, the extent of movement is greatly exaggerated in order to more clearly lrepresent Ithe character of movement of the floating work holder.

The supporting frame 175 has its hub notched at two `points at 900 apart, as indicated at 183. Each of these notches is adapted to receive'the engaging nose of a latch 184 pivoted at 185 in bearings on the upright arm 177 which supports the frame 175. A plunger 186 is received in a guide opening 187 in apart of the arm 177 and is pressed forwardly by an 4expansion spring V188 to cause the engaging nose of the latch to lock the carrier or supporting frame 175 against turning movement-on its pivotal support or. spindle 176. A finger piece 190 facilitates a disconnection -of the latch to enable the frame to be given a quarter turn on its pivot 176 to move one work holding device to aposition where a ground type bar may be readily detached therefrom, at the same time bringing a newly introduced bar to be ground, and which is carried by the other work holding device, to a position where it may be inserted between the grinding faces of the wheels 12 and 84. In

. short the pivotal movement of the frame or llti lll'.

head 175 on the arm 177 enables one holder to replace another in position for use.

The supporting arm 177 is provided with hubs 191 by which it is supported on a horizontal rock shaft 192 arranged parallel with the driving spindles 11 and 83, the shaft 192 being,` supported in suitable bearings on the frame of the machine. An arm 193 has a split hub held together by a screw and by means of which the hub is clamped to the shaft 192 to iixedly connect the arm 193 to the rock shaft. Said arm 193 in turn is connected by a pin 1911 and a screw 195 to the arm 177 to cause the latter to turn with the arm 193 and the rock shaft 192.

Referring more particularly to Fig. 4, it will be seen that a crank arm 196 is mounted by its hub 197 on the rock shaft 192 and is l'ircdly connected thereto by a screw 198. This arm extends rea fwardly and carries a laterally projecting-anti-friction roller 200 which is received in a cam slot 201 in a cam wheel 202 secured to the cam shaft 102. ln this manner the pivotal movement of the arm 177 and the parts carried thereby is automatically controlled by the cam 202. The character of the cam is such that a loaded work holder is first moved rearwardly to introduce the heel 7) of the type bar between the nrindin faces of the wheels, as represented in Fig. 3. Then the type bar receives a slight movement fore and aft of the machine duringthe grinding` operation. After the grinding operation is completed the arm 177 is moved forwardly to the limit of its motion in order to withdraw the ground vtype bar from between the 4grindingF wheels. The operator may then release the latch 18-1, give the frame 175 a quarter turn to bring` the other loaded work holdingv device in position to introduce its type bar between the wheels; this movement of the frame 175 carrying' the work holder with the ground bar tc one side where the latter may be readily removed and another type bar to be ground may be introduced in its place.

l have hereinhefore pointed out that the cam shaft 102, by which the fore and aft rocking` movement of the arm 177 is effected` also automatically controls the axial movement of the right-hand grinding; wheel into and out of grinding position. I also have pointed out that this cam shaft is controlled by the worm shaft 105 which automatically brings about an arrest of the cam shaft throueh an automatic disconnection of the worm 104 from its worm wheel 103 after a cvcle of operations has been completed. This cycle of operations is started by a depression of the handle 128 to connect the worm and worm wheel, and consists in first automatically moving` the arm 177 to introduce a type bar into posit-ion between the two grinding wheels; then automatically moving the right-hand grinding` wheel 12 against the heel of the type bar to automatically position the floating type bar with thc opposite sides thereof in parallelism with the grinding; faces of the wheels and effect a grindingv operation; a fore and aft movement of the arm 177 being;V effected during this grinding` of the type b: After the type bar has been ground the grinding wheel 12 is automatically moved to the right out of ,SWinding.;` position and the arm 177 is automatically ,Qjiven a movement forward to witlnlraw the around type bar from between the wheels. rlhis completes the cycle of operations and at this time the cam 113 actuates the arm 115 to release the lower end of the arm 117 from beneath the worm shaft and permit an automatic disengagement of the worm 104 from worm wheel 103, thus effecting an arrest of the cam shaft and the parts controlled thereby, Aalthough the grinding` wheels may be continuously driven from their pulleys 52.

lli-om the foregoing` description it will be understood that the heel of each vfloating type bar when introduced between the grindinn` wheels is free to receive a limited extent of lateral movement, or movement longitudinally of the axes of the grinding wheels in parallel planes as indicated in Fig. 10, or to assume different angular positions with reference to the axes of the wheels foil a limited extent as indicated in Figs. 17 and 18, although the type bar is held rmly in position ay inst movement with the grindwheels in the direction of their turningr movements. rfhis limited lateral movement of each work holder with its type bar enables the type bar to be `ground to automatically accommodate itself to the grinding` faces of the wheels and accurately find its proper position in parallelism therewith as the bar is pressed by and between the wheels. l't follows therefore that each articleis accurately ground on opposite faces in parallelism between the opposing faces of the grinding` wheels which alone restrain the lateral movements of the article, and that the positioning of the article to be ground, and the maintenance thereof in parallelism with the face. of the Heels,y is determined wholly by the direct contact of the lgrinding faces of the wheels on the article to he ground. @ther-wise stated the floatingl character of nach holder in operative position leaves the type bar unrestrained for limited extent of lateral movement except for the direct contact of the grinding;` faces of the oppositely disposed grinding' wheels therewith` and thus enables each type bar to properly position itself automatically as the wheels are moved relatively towards each other into contact with the bar, and bring the sides of the latter in accurate parallelism with the (lll faces of the wheels by the direct contact-of the latter with those surfaces of the type bar that are to be ground.

l prefer to provide a longitudinal opening extending entirely through one of the spindles 11 c1283 by which the associated grinding-` wheel. is turned in order to supply water or liquid to the interior of the cup shaped grinding wheels 12 and Se. ln Fig. 5 Al have shown such an opening 203 extending entirely through the spindle v11.y ln practice, however, l prefer to employ a corref-:ponding opening 204; through the lefthand spindle and to connect said opening` by means of'a pipe 204i-a (see Fig. 1) with a suitable source of supply by which liquid may be fed to the inner sides of the wheels. f desired a suitable valve 205 may be employed to control the flow of liquid from the source of supply. Such valve may be automatically controlled from a cam 205 on the cam shaft 102.

l may also kprovide suitable means for receiving liquid from the wheels and carrying it to a suitable point of discharge. In F ig. 8, 'I have shown a sheet metal trough 207 carried by the arm 17 7 and disposed opposite the space between the grinding wheels. This trough is adapted to discharge into a sheet metal trough 208 carried by the'lower section 209 of a two-part housing for the grinding wheels, or to discharge directly into a trough 210 formed in said lower section. trough 210 through the housing to an outlet 211 therein and then ce to a suitable point of discharge. The housing for the grinding wheels is separate and distinct from the supporting heads l and 5 and is mounted' on the ways 3 of the bed 2. ln addition to the lower section 209 the housing` comprises an upper section or cover A212 arranged 'over the wheels and pivoted at 213 to the lower section 209, so that the forward end of the upper section may be swung up and rearwardly to give access to the grinding wheels. lt will be seen that this section 212 is apertured at 214twhereas the lower section has a corresponding opening 215 (Fig. 1) to receive a work holder and permit the heel of the type bar to be received between the oppositely disposed grinding wheels. Suitable means maj,vv be provided to secure the upper section 212 in place. Referring particularly to Figs. 1 and 3 it will be seen that for this purpose I provide a link 216 pivoted zit its lower end, as at 217, in a slot in the lower section 209 of the housing and threaded at its upper end to receive a thumb nut`218. This link may be turned on its pivot into a registering slot on the forwardly extending flange 219 of the upper section'. When thus positioned, and the thumb nut 218 is turned down against the flange 219, the upper section of the housing will be firmly held in.'

The liquid may be conveyed from the place on its lower section. A backing up of the thumb nut enables the4 link to be turned forward to release the cover section of the housing.

A sheet metal cover plate 220 may be secured to each of the heads 4E and 5 over the quill 13 orll.

lllhen a hand controlled machine is to be provided, the cam shaft 102, the connections between said shaft and the parts controlled thereby, the worm wheel 103, and the various parts associated therewith are omitted. The arm 177 may then be provided with suitable. stop devices 221, 222 and 223 to limit the movements of the arm 177 both forwardly vand back, and the handle 178 may be employed to effect such movements of the arm. ylhe axial movements of the grinding wheel 12 is brought about by -a hand actuated crank (not shown) applied directlyto the squared end 82 of the rock shaft 81. Otherwise the construction and operation of the hand controlled machine is the same as that previously described.

` Suitable means, not shown, are provided for controlling the driving belts ofthe pulleys 52 to turn the grinding wheels in opposite directions in their grinding operation, and to reduce the speed `of the grinding wheels when they are brought into Contact with each other to dress the faces of the wheels by their mutual action one on the other.

From what has been said it will be understood that a work holder 150 cannot move lengthwise of the main carrying arm or primary support 177, and when in use is controlled and restrained in its movements toward and from the axes of the grinding wheels and in the direction of rotation of 'l the wheels, but is supported to move a limited distancerfree from restraint in every other direction, so that the direct contact of the `parallel grinding faces of the wheels with the article carried by the holder causes the article to accommodate itself to said faces and assume a position in parallelism therewith, .and receive an equal and true grinding on both sides between the wheels.

w lt also vwillrbe understood that the construction is such that the grinding wheels vare maintained against deviation from the true course in which they should turn and be fed axially one relatively to another; that when occasion requires the grinding faces of the wheels may be expeditiously dressed one by another without the necessity of dismounting any part of the machine or altering or destroying any adjustment ofthe parts required in grinding the type bars; it being merely necessary to shift the member 133A out of operative position; 'that .if any adjustment of the micrometer screw 1113 is required in dressing the wheels it may ordi- ;narily. remain in such `adjusted position after the dressing` operation for effective use in grinding, or, if conditions demand, maybe adjusted as required.

Various changes may be made without departing from the spirit of my invention, and certain features thereofI may be employed without others.

lVhat l claim as new and desire to secure by Letters Patent, is,

l. In a combined grinding and dressing machine, the combination of two grinding wheels operative to grind parallel faces on opposite side of the article to be ground, means for mounting said wheels to turn on unvarying parallel axes, and automatically operatin g means for effecting a relative axial sliding movement between said wheels into' and out of grinding relation with the article and when desired to bring the grinding wheels eccentrically arranged ene with reference to the other into contact to dress one wheel by the other.

2. ln a combined grinding and dressing machine, the combination of two cup-like grinding wheels the grinding face of each of which is in a plane at substantially right angles to its axis of rotation and by which opposite parallelv faces are ground on the interposed article, means for mounting said wheels to turn o-n parallel axes, and autovmatically operating means for effecting -a relative axial sliding movement between said wheels into and out of grinding relation with the article and when desired to bring the grinding wheels eccentrically arranged one with reference to the other into contact to dress one wheel by the other.

3. In a combined grinding and dressing machine, the combination of two grinding wheels that turn on unvarying axes and have a relative movement in the direction of the axes on which they turn to exert pressure against and act on the interposed article to be ground, means for supporting said wheels so that the grinding face of one wheel crosses transversely the grinding face of the other wheel, and means whereby said wheels may be brought into contact to dress one by the other.

4. In a grinding machine, the combination ofA two grinding wheels having parallel grinding faces adapted to be moved relatively one to the other and to simultaneously grind opposite parallel faces on the interposed article te be ground, a floating holder to which the article may be secured and by which it may be'brought and maintained between oppositely disposed parallel grinding faces on said wheels, and means for mounting said holder so that it has a controlled movement towards and from. the.

axes of said wheels and also a limited `uncontrolled incvement between opposingfaces n remind-le 0f.1tlie -V other wheel to -move the vwlneels :togethery 1n' grinding relation .one

of said pwheels and longitudinally .of fsai-d axes and at different angles thereto but Lis,-

inea-,lee

restrained against turning movement with said wheels.

5. In a grinding machine, the combination of two grinding wheels adapted to be moved relatively one to the other and to simultaneously grind opposite faces of the interposed article to be ground, a floating holder to which the article may be secured and by which it may be brought and maintained between oppositely disposed grinding faces on said wheels, and means for mounting said holder to turn on aries at substantially right angles one te another so that the article may be held restrained against movement between said wheels in certain directions but has limited uncontrolled movements between said wheels in other directions.

6. In a grinding machine, the combination of two grinding wheels havin Y oppositely disposed parallel Grinding faces by which an interposed article may be ground simultaneously on opposite parallel sides, a holder to which the article may be secured and by. which the article may be introduced and maintained between the parallel grinding faces of said wheels, and means for supporting said holder so Vthat it has a limited freedom of movement in certain directions controlled or restrained only by the parallel grinding 'faces of the wheels on the article, thus enabling the article to automaticallj-,fv find its position between and parallel to the grinding faces wholly by the pressure of the grinding faces thereon.

7. In a ,C rindingmachine, the combination of two grinding wheels having oppositely disposed parallel grinding faces by which an interposed article may be ground simultaneously on opposite parallel sides, a holder to which the article may be secured, and means by which said holder may be shifted to introduce and maintain the article to be ground between the parallel grimling faces of said wheels and which enable the holder to receive a limited unrestrained lon movement between said wheels to bring the h varranged end to .endlbut-out of axial' alignment, a grinding wheel. carried by each spindle and between which the article may be received ya-nd ground by said wneels arranged on'e eccentrically of the other, and a hollow oil containing bearing member supporting-one of said spindles in a bath of oil and mounted for axialsliding movement wit-hits spindle towards and away from the fill against the other or separate them, whereby the wheels may be dressed one by the other.

9. ln a combined grinding and dressing machine, the combination of two spindles arranged end to end but out of axial alignment, a grinding wheel carried by each spindle and between which the article may be received and ground by said wheels arranged one eccentrically oi ythe other, a bed, a head adjustable along said bed, and a bearing member supporting one of said spindles and mounted l'or axial sliding movement with its spindle on said head towardskand awayv from the spindle ot the other wheel to move the wheels together into grinding relation with the interposed article to Abe ground or separate the wheels, and also to enable the wheels to bear one against the other to dress them one on the other.

lO. ln a combined grinding and dressing machine, the combination ot two spindles arranged end to end but out ot' axial alignment, a grinding wheel carried by each spindle and between which the article may be received and ground by said wheels arranged one eccentrically ot the other, a bed, a head adjustable along said beda bearing member supporting one ot said spindles and mounted for axial sliding movement with its spindle on said head` towards and away irom the spindle ot the other wheel to move the wheels together into grinding relation or separate them, a bearing on said head, a driving pulley mounted on said bearing, and a pin and slot connection between said pulley and the associated spindle and by which the spindle is turned by the pulley but an axial movement of the spindle independently of the pulley may be eitected.

ll. ln a combined grinding and dressing machine, the combination ot two spindles arranged end to end but out of axial alignment, a grinding wheel carried by each spindle and between which the article may be received and ground by said wheels arranged one eccentrically of the other, means lor mounting said spindles with the wheels thereon for relative axial sliding movement toward and away troni each other, and an interponent movable into and out of vcooperative relation with. a part that moves axially with one ot said spindles and is adapted to arrest the axial movement thereet, said interponent when moved out of cooperative relation permitting the wheels to bear one against the other to dress the wheels. y

l2. ln a combined grinding and dressing machine, the combination of two spindles arranged end to end but out ofaXial alignment. a grinding wheel carried by leach spindle and between which the article may be received and ground by said wheels arranged one eccentrically of ythe other, a bearing member supporting one of said spindles and mounted for aXial sliding movement with its spindle towards 'and away from the spindle of the other wheel, an interponent movable in to and out of cooperative relation with a part carried by said bearing member and adapted to arrest the latter in its axial m vement, and means for eiiecting an adjustment ot said part to different set positions on said bearing member; i

13. ln a combined grinding and dressing machine, the combination or' two spindles arranged end to end, a grinding wheel carried by each spindle and between which wheels the article may be received and ground by said wheels, a bearing member supporting one of said spindles and mounted for axial sliding movement with its spindle, a part carried by and adjustable Yto diilerent set positions on said bearing member, and an interponent movable into and out ol co-operative relation with said ad-l justable part and adapted to co-act therewith to ar est the bearing member in its axial movement, said interponent when moved ont ot co-operative relation permitting the wheels to bear one against the other to dress the wheels. Y

14. ln a combined grindingand dressing machine, the combination of two spindles arranged end to end, a grinding wheel carried by each spindle and between which wheels the article may be received and ground, a hollow oil containing bearing member snpporting one of said spindles in a bath'oi oil and mounted for axial sliding movement with its spindle towards and away from the spindle of the` other wheel to move the wheels together in grinding relation or serparate them, a part carried by said bearing member, an interponent movable into and out of coi-operative relation with said part and adapted to co-act therewith to arrest the axial movement of said bearing member and the parts carried thereby, and means tor affording an adjustment of saidpart to different set positions on said bearing member.

15.111 a combined grinding and dressing machine,the-combination of two spindles arranged end to end, a grinding wheel carried by each spindle and between which wheels the article may be received and ground, a bed, a head adjustable along said bed, a bearing member supporting one of said spindles and freelyy mounted for axial sliding movement with its; spindle en Said head towards and away from the spindle of. the other wheel to move said wheels together into grinding relation or to separate them, and an interponent movable into and out of operative position and adapted to arrest said bearing member and the parts carried thereby in their axial movement or leave them free from arrest by said interllO llli

ponent so that one wheel may coact with the other to dress the wheels.

lli'. In a combined grinding and dressing machine, tho combination of two spindles arranged end to end, a grinding wheel carried by cach spindle and between which wheels the article may be received and ground, a bed, a head adjustable along said bed, a bearing' member` supporting one oit said .pindles and mounted lor axial sliding niovenient with its spindle on said head towards and away from the spindle o'l' the other wheel to move said wheels together into grinding relation or to separate them, a bearing lined on said head, a driving pulley mounted on said bearing, and a pin and slot connection between said pulley and the associated spindle by which the spindle is turned by the pulley but an axial movement otl the spindle independently of the )alley may be effected,

l. ln a grinding machine the combination ot a pair of oppositely disposed grinding wheels between which an article is received and by which the article is simultaneously ground on opposite faces, means for ctlecting a relative axial movement between the grinding wheels to cause them to coact with the article to be ground, and means tor supporting` the article to be ground', said last Vmentioned means comprising an automatically actuated pivoted arm, a holder to which the article to be ground may be secured, and intermediate connections between. said holder and arm that enable said holder to move to different parallel planes and to different angular positions relative to said planes but which )reventa the holder from moving lengthwise t said arm, a pivotal movement of said yrin moving the article to be ground towards ant. from the axes ot' said wheels.

18, lin a grinding machine, the combination ot a pair ot oppositely disposed grinding wheels between which an article is received and by which the article is simultaneously ground on opposite faces, and means for supporting the article to be ground, said means comprising a pivoted arm, a holder to which the article to be ground may be secured, and inter nediate connections between said holder and arm that include a plurality of pivoted supporting members, the pivotal axes of which are in planes at substantially right angles one to another,

19. ln a grinding machine, the coin-bination of a pair-of oppositely disposed grinding vf'l eels between which an article is lreceived and by which the article is ground on opposite faces, and means for supporting the article to be ground, said Vmeans comprism@- a pivoted arm, a holder to which the arti `le to be ground may be secured,

and intermediate connections -between said holder and arm including a support pivotally connected to said arm and having its pivotal axis extending at substantially right angles to said arm, a second support pivoted on said first` mentioned support and having its pivotal axis substantially parallel with that of the first support, and a third support which carries the holder and has its pivotal axis at substantially right angles to that ot the second support.

Q0. In a grinding machine, the combination ot' a pair ot oppositely disposed grinding wheels between which an article received and by which the article is ground on opposite faces, and means `tor suppintingl the article to be ground, said means conprising a pivot-ed arm, a holder to which the article to be ground may be secured, and intermediate connections between said holder and arm that enable the holder to receive a limited unrestrained movement `laterally et the arm and at different angles thereto so that the article on the holder is positioned in parallelism with the grinding faces of the wheels by said Contact ol.E the grinding faces therewith.

2l. ln a grinding machine the combination oi a pair of oppositely disposed grinding wheels mounted on substantially horizontally disposed spindles, and means for supiliorting the article to'be ground between said wheels, said means comprising an arm pivoted to turn on a substantially horizontally disposed axis, a support pivotally connected with said arm to turn on a substantially horizontally disposed axis, a second support pivotcd to the lirst mentioned support to turn on a substantially horiZontallj-I,Y disposed axis, and a third support which carries the holder' and is pivoted to the second support. to turn on. a substantially vertically disposed axis.

22. In a grinding machine, the combination ot' a pair of oppositely disposed grinding wheels mounted on parallel axes and between which the article to be ground is received and ground on opposite sides, and automatically operating means by which the article is introduce-d liietween said wheels; by which a relative movement of the wheels towards each other is effected to cause them to bear against the article; by which the article is moved back and 'forth during the grinding operation; by which the wheels are moved relatively away from each other alter the grinding operation is completed; and by which the ground article is withdrawn from between the wheels.

ln grinding; machine, the combination ot a pair oit opnositely disposed grinding wheels between which the article to be ground is received and ground on opposite sides,- automat cally operating means l lli the above described cycle of operations has been effected.

24. In a grindingmacliine,the combination of a grinding wlieel,'means for moving said wheel against the articleto be Vground and which includes a positively actuated meinbei` and a resilient member through which said movementis transmitted to the wheel from said positively actuated member, and a stop to positively arrest the said movement of the wheel under the action of the resilient member. i

25. In a grinding machine, the combination of a pair of grinding wheels, means for effecting a relative movement between said wheels to bring about a contact thereof with the article tobe ground between them and which includes a `positively actuated member and a resilient member through which said relative movement between the wheels is transmitted from said positively actuated member, and adjustable means for positively arresting` and limiting said relative movement of the wheels under the action of said resilient member.

Q6. In a grinding machine, the combination of a pair of grinding wheels, and autoiiiatically operating means for effecting relative forward and back movements between said wheels, said means including positively operatingiiioving devices, and a resilient member intermediate said moving devices and a part to be moved to effect the said relative movement vof the wheels, the relative movement between the wheels in both directions being effected by said positively operating devices acting through saidresilient member.

27. In a grinding machine, the combination of a pair of grinding wheels, automatically operating means for effecting relative forward and back movements between wheels, said means including positively operating` moving devices, and a resilient member intermediate said moving devices and a part to be moved to effect the said relative movement of. the wheels and through which motion is transmitted from said positively opeiating` devices, and an interponent movable into and out of operative position and when in the operative position adapted to arrest the relative movement of said wheels towards each other and when out of operative position permittingthe face kof one 'wheel to be dressed by the other.

28. In a grinding machine, the combination of a pair of grinding wheels, automatically operating means for effecting relative forward and baclr movements between said wheels,- said means including positively operating moving devices, and a resilient member intermediate said moving devices and a part to be moved to effect the said relative movement of the wheels and through which motion is transmitted from said positively operating devices, an interponent movable into and out of operative position and when in the operative position adapted to arrest the relative forward movement between said wheels, and when out of operative position permitting the face of one wheel to be dressed by the other, and relatively adjustable stop devices adapted to arrest such relative movement of the wheels when the interponent is in the inoperative position.

29. In a grinding machine, the combination of a grinding wheel, automatically operating means for ,controlling the movement of an article into and out of co-operative relation with the grinding wheel and forV controlling the movement'` of the wheel against and away from the article, and automatically operating means for disconnecting the driving means for said firstl mentioned automatically operating means after its cycle of operations has been completed.

30. In a grindingmachine, the combination of a grinding wheel, automatically operv ating -means for controlling the movement of an article into and out of co-operative relation with the grinding wheel and for controlling the movement of the wheel against and away from the article;,and automatically operating means forV disconnecting the driving means for said first mentioned autoniatically operating means after its cycle of operations has been completed.` said auto- .inatic disconnect mechanism including means that enable two gears to be thrown out of mesh, means for supporting said gears in mesh, and automatically operating means for releasing said supporting means.

31. In a grinding machine, the combinalitiy tion of a grinding wheel, automatically-l operating means for controlling the movement of Van article into and out of co-operative relation with the grinding wheel and for vcontrolling the movement of vthe wheel against and away from the' article, auto-V matically operating means for disconnecting the driving means for said first mentioned automatically operating means after its cycle of operations has been completed, said auto-

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