US1812313A

US1812313A - Grinding machine

Info

Publication number: US1812313A
Application number: US9107A
Authority: US
Inventors: Arter William; Warren F Fraser
Original assignee: ARTER GRINDING MACHINE Co
Current assignee: ARTER GRINDING MACHINE Co
Priority date: 1925-02-14
Filing date: 1925-02-14
Publication date: 1931-06-30
Anticipated expiration: 1948-06-30

Description

June 30, 1931. w. ARTER ETAL 1,812,313

GRINDING MACHINE le eb- 1925 6 Sheets-Sheet l ATTORNEY F 1 a ms mans June 30, w RTER ET AL 1,812,313

GRINDING MACHINE Filed Feb. 14, 1925 6 Sheets-Sheet 2 24 I w 125 27 l5 //2 z E 73 I 2 INVENTORS F g. 2 mm BY M a; JW

' HTTORNEY w. ARTER ETAL 1 ,313

d-RINDING MACHINE June 30, 1931.

Filed Feb. 14, 1925 6 Sheets-Sheet 4 [NVEPITORS I TTORNEY June 30, 1931. w. ARTER ETYAL 1,812,313 I I GRINDING HACHINB Filed 1925 e Sheets$heet 5 E9; mi

June 30, 1931 w ARTER ET AL 1,812,313

GRINDING MACHINE Filed Feb. 14, 1925 e Sheets-Sheet 6 Z I |N\/ENTOR5 o M I (9' BY W W fi /qTToRNEY Patented June 30, 1931 UNITED STATES PATENT OFFICE WILLIAM ARTER, 0F WORCESTER, AND WARREN F. FRASER, OF WESTBORO, MASSA- CHUSETTS; SAID FRASER ASSIGNOR TO ARTER GRINDING MACHINE COMPANY, OF WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS GRINDING MACHINE Application filed February 14, 1925. Serial No. 9,107.

This invention relates to machines for shaping metal articles through the use of abrading or grinding elements, such machines being herein referred to as grinding machines.

It is the chief object of the present invention to devise a grinding machine which will handle. a great variety of metal parts on a production basis. The invention is especially concerned with a machine of this type adapt ed to operate on round work, either straight or tapered, and with or without shoulders.

A further object of the invention is to devise a machine of the character indicated which will be so. completely automatic as to substantially eliminate the necessity of skill on the part of the machine attendant or workman, to reduce to a minimum the attention required by the machine, and to facilitate the handling of the work, more especialmechanism, and novel means for handling the work and presenting it to or removing it from the machine. These and other features of the invention to be hereinafter described in detail will be readily understood from the following description, and the novel features will be more particularly pointed out in the appended claims.

In the accompanying drawings,

Figure 1 is a front elevation of a machine embodying this invention;

Fig. 2 is a side elevation of the machine shown in Fig. 1 with certain of the parts broken away;

Fig. 3 is a vertical cross sectional View on the line 33, Fig. 1;

Fig. 4 is a side elevation showing the wheel dressing mechanism;

Fig. 5 is a cross sectional View on the line 5--5, Fig. 4;

Fig. 6 is a cross sectional view on the line 6'6, Fig. 4;

Fig. 7 is a cross sectional view on the line 77, Fig. 8, showing part of the mechanism for controlling the rate of approach of the presser head toward the grinding wheel, and apparatus associated with said mechanism;

Fig. 8 is a side view, partly in cross section. of the mechanism shown in Fig.7

Fig. 9 is a side elevation, partly in cross section, of the work holder and the mechanism for moving it into and out of cooperative relationship to the grinding wheel;

Fig. 10 is a plan view, partly in cross section, of the mechanism shown in Fig. 9;

Figs. 11 and 12 are vertical, cross sectional views through one side of the grinding wheel and the adjacent parts-showing different types of work being operated upon;

Fig. 13 is aside view, partly in cross section, of another mechanism for lifting the work holders; m

Fig. 14 is a fragmentary cross sectional view through one of the pockets of the work holder; and

' Fig. 15 is an edge view of a small portion of the work holder.

Briefly stated, the machine shown comprises a horizontal grinding wheel with mechanism for supporting and rotating it, a presser head which presses the work against the grinding wheel, and a work holder which is mounted between the presser head and the grinding wheel and positions the work with reference to the wheel. A power driven mechanism is provided for raising and lowering the head, this mechanism being arranged to permit the head to approach the; grinding wheel by gravity, and an automatic mechanism is provided to control the rate of this approaching movement. This movement is definitely limited by a stop, and the machine is equipped with mechanisms for automatically stopping the rotation of the grinding wheel and also interrupting the approaching movement when the relationship to the grinding wheel. The machine also includes a crane for engaging the Work holder and moving it into and out of its operative position,'a wheel dressing mechanism, and a pump and tank for holding and circulating the" lubricant used in grinding. The various mechanisms will be taken up for detailed description in substantially the order in which they have just. been mentioned. 7

Referring first to Figs. 1 and 3, the grind ing wheel is indicated at 2, this wheel being mounted on an annular flange 3 which is re-' movably secured to a bracket or wheel support 4 mountedon the upper end ofa verti'cal shaft 5. The bearing mechanism which supports theupperend of this shaft preferably is like that shown in' the .Arter Patent No. 1,289.358, dated December'31, 1918. Supporting the lower end of this shaft is a tapered'sleeve 6, split on one side, which receives an oppositely tapered sleeve-7 that is secured to a'stationary part of the machine. A cap 8. is bolted to the lower end of'this frame part and has threaded engagement with the sleeve 6 so that this sleeve mav be vertically adjusted to take up wear by adjusting the cap 8. It will be observed that the upper bearing 9 for the shaft 5 is of conical form and that it supports the weight of the shaft 5 and the' parts carried thereby. the lower bearing 6 being simply a guide hearing. The bearing 9 is supported in a heavy bracket 10 which'rests in a central aperture formed in'the base 12 of the machine frame.

For the purpose of driving the shaft 5 and the grinding wheel 2, a spiral gear 16 is keyed to said shaft and meshes with another spiral gear fast on a horizontal shaft'17. A pulley 18, Fig. 1, rotates freely on this shaft and has a clutch face arranged to be engaged by a slidable clutch element 19 which is keyed to the shaft and. is backed up by a spring 20, this clutch being controlled by a clutch lever 21. The pulley 18 is driven by a belt connection from the pulley 22. on the main driving shaft 24. this shaft carrying a pulley 25' by means of which it may be connected to any convenient source of power.

The work' is held against the grinding wheel 2 by an annular presser head 27 which is adjustablv secured to the lower end of a vertical shaft or rod 28. This rod is guided in upper and

lower bearings

29 and 30, re-

spectively, mounted ,in the ma'chine'fra'me,

these bearings being-of the general type of that shown at 6-7 and above described. A universal joint connects the lower end of the rod 28 with the head 27, this joint comprising a spherical member 31 secured rigidly to the rod and upper and

lower socket plates

32 and 33, respectively, which are clamped upon the spherical member 31 by means of three bolts 34, Fig. 1. The lower plate 33 is bolted to the head 27 By loosening the bolts 34 slightly and lowering the head 27 into contact with the wheel 2, and then tightening the bolts 34 again, the head can be secure in absolute parallelism with the upper surface of the wheel 2. i

The work holder is normally supported between the driving wheel 2 and the presser head '27. This holder comprises a disk 36, Figs. 3, 9 and 10, which preferably is some what concaved, and has a series of pockets 37 to receive the rolls or other pieces of work W. Preferably these pockets are inclined with referenceto aradius of the disk, as best shown in Fig. 10, and in order to minimize the tendency of the work to wear grooves in the grinding wheel, the holder is mounted to rotate with the work but about an axis which is eccentric to the axis of rotation of the wheel 2. For this purpose a short pin or stub shaft 38 is secured at the lower end of the slide or rod 28- in an eccentric relationship to the shaft 5, as will be seen from an inwheel and thus distributes the wear.

For the purpose of raising and lowering the presser head 27 a power drivenmecha nism is provided which comprises a vertical screw threaded shaft 42 mounted immediately behind the ruler slide 28. Threaded on this screw is a nut or follower 43, Fig. 3, having an extension that projects through a vertical slot 41 in the frame of the machine so that the follower 43 can move upor down but cannot rotate. Resting on this nut or follower is a bracket 44 which is rigidly secured to the slides 28. A bevel gear 45 is secured to the upper end of the shaft 42 and is arranged to mesh with two bevel gears 46 and 47 both mounted loosely on the horizontal shaft 48, Figs. 1 and 3. These two gears are provided. with clutch portions arranged to mesh with to the shaft 48 and is arranged to be moved backward and forward on the shaft by a shipper51, Fig. 3. This ship-per is secitred on the upper end of a vertical rock shaft 52, and a hand lever 53 is secured to this shaft to permit manual operation thereof. Consequent- 1y. by moving this lever in one direction or the other. as desired. the shaft 42 may be rotated to raise or lower the presser head 27. Power is transmitted to this mechanism by a belt (not shown) which connects the pulley 54 on the shaft 48 to another pulley 55 on the main shaft 24.

In order to prevent the presser head from overrunning in either its upward or downward movement, the rock shaft 52 has two

cam members

56 and 57 adjustably secured thereto, and the bracket 44 carries a pin 58 and the nut or follower 43 carries a pin 59 to engage these cam members. When the shaft 42 is rotatin in the proper direction to lift the head 27, the pin 58 will, at a. point predetermined by the setting of the cam 56, engage said cam and rock the shaft 52 far enough to throw the shiftable clutch member 50 into its central or neutral position. This stops the upward movement of the presser head. When the mechanism is operating to lower the presser head and the head has reached a point near the lower limit of its movement, the pin 59 will engage the lower cam member 57 and rock the shaft 52 in the opposite direction far enough to throw the member 50 into its neutral position and thus stop the rotation of the shaft 42. This lift-' ing and lowering mechanism for the dresser head must, therefore, be thrown. into operartlOIl manually and it can be stopped by hand, but if'it is not so stopped it will stop automatically when the head has reached a predetermined elevation.

As above stated,'when the machine is in 2 operation the head 27 holds the work against the face of the grinding wheel 2. It will be evident from an inspection of Fig. 3 that when the mechanism above described is lowering the head, it is not positively producing a lowering movement but is simply allowing the head to drop by gravity at a rate determined by the pitch and rate of rotation of the screw 42. This mechanism cannot produce a positiveloweri'ng movement of the head due vto the fact that the bracket 44 simply rests on the nut or follower 43, the screw 42 having no positive engagement with the bracket 44. This mechanism, however, is utilized to lower the head into engagement with the work or until sto ped, as hereinafterdescribed, and therea ter the follower 43 moves downwardly out of engagement with the bracket 44. If this mechanism alone were depended upon to control the movement of the presser head, it is evident that the work would be subjected to a pressure equal to the entire weight of the head and the parts movable therewith. For some classes of work this pressure is desirable, but for other work it would be. too great. Consequently, these uated dial 61 arranged to cooperate with a stationary pointer 62. When the head is lowered by the power mechanism above .described, it descends with the follower 43 until the screw 60 strikes thestop 63. Thereafter the head can only descend with the stop. The mechanism for permitting the lowering movement of the stop is best shown in Figs. 7 and 8. From an inspection of these figures it will be seen that the stop 63 rests on a wedge 64 which, in turn, is supported by another wedge 65. The inclination of the contacting surfaces of these two wedge members is very slight. A spring 66 bears against one end of the Wedge 65, while a screw threaded shaft 67 bears against the opposite end of the wedge. This shaft rotates in an internally threaded stationary bushing 68; Splined to this shaft is the driven member 70 of a clutch, the driving member 71 of which is secured to the face of a worm wheel 72 driven by a worm 73 on a shaft 74 which, in turn, is driven by a worm gear connection with another shaft 75 having a stepped pulley 76 fast thereon. This pulley'is driven by round belt connections with another stepped pulley 77, Fig. 1, which is adapted to be driven from a third stepped pulley 78 on the main shaft 24. The

driving ratio between the main shaft 24 and the screw shaft 67 thus is very high so that the speed of the shaft 24 is tremendously reduced, a maximum reduction of about three thousand to one being obtained in practice, and this ratio can, of course, be adjusted by the stepped pulley construction above described. As the shaft 67 rotates it is moved very gradually endwise through the bushing 68, thus forcing the lower wedge 64 toward the left, Fig. 7, and allowing the stop 63 to settle very slowly. Since the head 27 cannot descendmore rapidly than the stop 63, this mechanism definitely limits the rate at which the presser head can approach the grinding wheel. The rate at which the grinding operation proceeds, therefore, can be controlled by properly adjusting the rate of descent of the presser head. This rate will be adjusted, of course, in accordance with the nature of the work, the character of the grinding wheel used, and other conditions which will be evident to those skilled in this art.

In order to automatically stop this approaching movement'when the head 27 has arrived at a predetermined distance from the upper surface of the grinding wheel 2, a wheel 82 having a graduated periphery is secured-to the screw shaft 67. A stop 83 projects laterally from this wheel and when the shaft 67 has rotated through a predetermined angle, the pin 83 engages a pin 84 projecting from one arm of a bell crank lever 85 and moves this lever. This movement is transmitted through a lever 86, Fig. 8, rock shaft 87, and clutch shifter 88, Fig. 7, to the clutch. member 70, thus disengaging this member from the driving clutch member 71. Thus the rotation of the screw shaft67 is immediately stopped, and consequently the descending movement of the head 27 is stopped. I I r The movement of the lever 85 produced in the manner just described is also utilized to stop the rotation of the grinding wheel 2.

For. this purpose the shaft on which the lever 85 is fulcrumed is rigidly connected to the movable valve member 90," Fig. 8. This valve is mounted inside a hollow valve casing ,91 to which compressed air is supplied from a pump. (not shown). It will ;be evident from an inspection of Fig.8 that when the lever 85 is moved in the direction described, the valve 90 will then permit the, flow of air through the passages 92 to the c linder formed in the cylinder block 93. this cylinder is a piston 94.- which is forced toward the left, Fig. 8, by the air admitted as just described. The movement of'the piston is transmitted through a bar 95 which is ivoted to the piston and through a yoke 96, igs. 1,

. 7 and 8, to a rod'97 which is connected to the upper end of the clutch lever 21, above referred to. This movement throws out theclutch against the action of the sprin 20, thus disconnecting the grinding wheel om its source of power and causing the wheel to stop.

spring therefore tends to hold the In order toadjust the extent of the gradual lowering movement of the presser-head produced in the manner abovedescribe a tubular sleeve or barrel 100, Figs. 7 and 8, is adjustably' secured b a set screw -.101 on a reduced portion of t e housin 102 that encloses the clutch 70 71 and t e driving position, the angular distance that the pin 83 will have to travel before it strikes the pin' 84 can be adjusted.

The spring 105 also performs the function of resetting the screw shaft 67 and the disk 82 in their initial positions after the approaching movement has been stopped. That is, the rotation of the shaft 101 produced in the manner above described winds up or.

tensions the torsion spring 105. After this approaching movement has been interrupted by the disengagement of the clutch member 70 from the member 71, the torsion spring immediately rotates the shaft 67 backwardly until the pin 104 strikes the stop 103. In other words, it returns both the disk 82 and the shaft 67 to their initial positions. As

soon as the worlnnan has moved the lever 53 to effect the raising of the presser head 27,

and thus carry the micrometer screw upwardly away from the stop 63, the coiled spring 66, Fig. 7, will then nfove the wed e toward the right, forcing it against t e end of the screw shaft 67 and thus resetting the wedge in its initial position,

It will therefore be observed that when When it is subsequently desired to start this mechanism into operation again, it is simply necessary to throw the lever85, Fig. 8,

into the position shown in said figure, this motion re-engaging the clutch member '70 with its cooperating member '71 and moving the valve 90 into position to permit the escape of air from the cylinder and thus allow the spring 20, Fig. 1, to re-eng'age the clutch 19 with the pulley 18.

As above stated, the work holder 36 is designed to hold a series of pieces of work in the properpositions on the surface of the grinding wheel 2 as the grinding operation progresses. Preferably t is work holder is so constructed that it will also support the articles of work independently of the grindin wheel. That is, the pockets in the work ho der, while open at their lower ends, are not wide enough to allow the articles of work to drop through them (seeFigs. 14 and 15) the work being placed in the pockets from above or else inserted in the outer ends of the pockets. For convenience in. manufacture we prefer to make the holder as shown in Figs. 9 and 10 with a rim 107 which is bolted to the main body 36 of the work holder, the rim itself having the pockets 37 formed there in. The outer margin of this rim is provided with a series of holes 108, Fig. 10 to receive one or more dowel pins that project downwardly from a retaining ring 109 that'simply rests on the rim. The ring 109 thus prevents the articles of work from escaping through endwise'movement' fromtheir pockets in the work holder. It will be understood that the nature of this retaining ring and the manner in which it is supported and to some extent, also, the construction of the work holder 107 will depend upon the nature of the work. For example, Fig. 11 shows a work holder designed for handling poppet valve lifters where the cylindrical portions are tobe ground, and in this construction the retaining rin 109' has parts arranged-to engage the hea of the valve lifters and limit their outward movement. Also, in Fig. 12, which shows an arrangement adapted for handling tapered pins or rolls, the retaining ring 110 is bolted to the outer surface of the presser head 27 but, performs essentially the same functions as the ring 109, Fig. 9. For convemence in removing'the work holders with the pieces of work loaded in them and replacing them againin-operative position in the machme, two cranes preferably are provided mounted on opposite sides of the machine, each crane being a duplicate of the other. Referring to Figs. 9 and- 10 it will be seen that each crane comprises an arm 112 pivotally mounted on ashaft 113 which is supported in a bracket 114, Fig. 1. The hub portion of the holder 36 includes a flange 115 and the end of the arm 112 is provided with an open sided, recess or slot adapted to receive said hub with the flange 115 resting on-the upper surface of the slotted portion of the arm. Secured to the arm 112 immediately above the post or shaft 113 is a cap 116 which is internally threaded to receive a screw 117 having a hand wheel 118 secured thereto. The

lower end of this screw bears on a' block 119 which rests on the top of the post 113. Consequently, after the arm has been engaged with the holder, as shown in Figs. 9 and 10, this arm and the holder may be lifted; together by rotating the hand wheel 118 in the proper direction. When the holder and the work have been raised clear of the grinding wheel 2, it is then a simple matterto swing,

the arm 112 in the proper direction to carry crane at the opposite side of the machine may be swung into its operative position, this holder having previously been loaded with pieces of work while the grinding operation has been going on. The holder just removed may be unloaded and reloaded again in readiness to be moved into operative relationship to the grinding wheel when the machine is again ready to receive it. In order to facilitate the movement of-the work holder into 'alinement with the stub shaft or pin 38, a short arm 120 is secured to or formed integral with the crane arm 112 and is arranged to engage a stop 121, Fig. 10, provided on the base 12 of the machine. As soonas the crane has been operated to position a work holder in the machine, the hand Wheel 118 is turned to lower the holder upon the grinding wheel 2, and the arm 112 is then swung out of engagement with the work holder and moved into its idle position.

The wheel dressing mechanism provided by this invention is arranged to be operated either manually or by power, as may be desired. This mechanism is best shown; in Figs. 4, 5 and 6. It comprises a bracket 124 pivoted at one side of the grinding wheel 2 and supporting an arm 125 in the end of which a tool holder 126 is mounted. This tool holder may be of the general type now used for this purpose, and it supports a diamond point 127which constitutes the wheel dressing tool. In performing this wheel dressing operation the tool 127 n'iustmore entirely across the working face of the grinding wheel 2, and for this purpose the bracket 124 is clamped securely on a vertiral rock shaft 128 which is supported in suit able beasings. Secured to the upper end or this rock shaft is a segment 130 of a worm wheel meshing with a worm 131 secured on a horizontal shaft 132. A hand wheel 133 is splined to the outer end of this shaft so that by rotating this ban (1 wheel the dressing tool 127 may be swung backward and forward across the face of the wheel 2. This tool may be adjusted vertically in the tool holder 126 by manipulating the nut 134 which is threaded on a screw 135 that carries the tool 127.

The power driven mechanism for operating the wheel dresser is arranged to be either connected with, or disconnected from, the shaft 132, as may be desired. For this purpose the hub portion of the hand wheel 133 is provided with a tapered annular clutch member 136 adapted to engage with the complemental face of a clutch member 137 which preferably is formed integral with a bushing rotating loosely on the shaft 132 and secured to a worm wheel 138. A nut 139 threaded on the reduced end portion of the shaft 132 bears against the clutch member 136 so that by turning this nut up, the latter clutch member maybe moved into driving engagement with the part 137. If the nut 139 is loosened, the part 136 will disengage the clutch member 137. The worm wheel 138 is driven bya worm (not shown) fast on a'shaft 140. This shaft has two

gears

141 and 142 rotating loosely thereon and each having a clutch face arranged to be engaged with a slidable clutch member 143 which is keyed to the shaft 140. The gear 142 meshes with a gear 144 on another shaft 145, while the gear 141 is driven through an intermediate idler gear from a gear 146 also secured on the shaft 145. This shaft carries a pulley 147 adapted to be belt connected to. a pulley 148, Fig. 1, on the main shaft 24. The slidable clutch member 140 may be shifted backward or forward by means of a hand lever 150. Consequently, by shifting the lever 150 backward and forward, the operator can cause the mechanism above described to traverse the dressing tool 127 backward and forward across the face this dressing operation the workman will' produce a rough dressing by manually trav- 10 presser head down on the grinding wheel while the latter is rotating and keep it there.

- until the wheel'has acted onthe entire lower face of the presser head. The head is next lifted and .th'ework is then inserted in the machine through the use of the work holder and one of the cranes, as also described above. The operator next moves the lever 53 in the proper direction to cause the head 27 to descend rapidly toward the work, this vmove- ,ment also serving to enter the stub shaft or pin 38 in the aperture of the work holder 36, as shown in Fig. 3. The'descent of the-head is stopped by the engagement of the head with the work, the follower 43 overrunning and being stopped through the automatic actuation of the clutch shipper 51, as'above described. T he micrometer screw 60 should now be turned down until itengages firmly with the stop 63, then the head 27 should be raised :13. d the micrometer screw advanced, say, two-'- ten thousandths of an inch more and the head then allowed to descend until the screw again engages the stop. The operator should previously haveadjusted the barrel 100 so that a predetermined reduction in thickness of the work will be produced during the gradual approaching movement of the 'presser'headl-to-* ward the grinding wheel.- 1 This setting can be made accuratel'y'due to the fact'that the 40 disk 82 is graduated in,divisionswhichlcor respond to movements of the presser head.

of one ten-thousandthsof an inch. Assuming that the work is" to be reduced approximately ten ten-thousandths of an inch, the disk 82 will'be correspondingly adjusted and the hand lever 85v will then be moved into'the position shown in Fig. 8, thus starting the 170- tation of the grinding wheel 2 and initiatingthe operation of the mechanism; that limits the work consequently has been reduced by w an amountdetermined by the setting of the gradual approaching mechanism, the grinding operation will-be stopped automatically. The operator may then lift the head 27 through the operation of the power raising and lowering mechanism, remove a piece of the rate of -descentof the. presser. head 27. The grindingloperation will then commence, 1 the 'head27 bearing on the pieces of work I .and holding them against the upper surface of'the' grindingwheel, the pressure which work and caliper it to see if it has been reduced to the required dimensions. If he finds that'the work is still a few te'n-thousandths over-size he readjusts the disk 82 and starts up the machine again after first lowering the head 27 into contact with the work. Or,

he may back off the micrometer screw and dial by the desired amount and then repeat will indicate the proper setting of the disk 82 and micrometer screw 60, and thereafter it will be unnecessary to change the setting of these members until a change in work is made, or a change in the setting of the screw is necessar to compensate for wear of the grinding whee The settin of the micrometer screw determines the point at which the lowering movement of the head 27 produced. by the power raising and lowering mechanism will be stopped and the head brought into the control of the mechanism that effects the gradual approaching movement. It also determines the position of the head 27 at the time of starting the grinding operation. This screw should be so set that whenthe head is' initially brought into contact with the work it will exert approximately the desired pressure on the work for the commencement of the grinding operation.

Another adjustment that may be necessary in starting the machine intooperation is to change the relativeeccentricity of the work holder and grinding wheel.- This is controlled by the adjustment of the bracket 10,

Fig. 3, in the base 12 ofthe machine 'frame. This bracket is mounted to slide slightly to the left or right, Fig. 3, boththe bracket 10 Y and base 12- being grooved to receive keys" l52-152 which permit this sliding movement but prevent the bracket from moving transcluding the grindingwheel 2,- may'bemoved 7 toward the right or left. When adjusted the y loosening one of these nuts bracket 10 issecured in position by bolts 155,

Fig. 1. p I

The degree: of eccentricity between the grinding wheel and the holder need not be great, but should be suflicient to prevent the work from wearing grooves in the grinding wheel. As the pieces of work roll between the presser head 27 and the grinding wheel 2, they rotate-the work holder but at a slower speed than that of the grinding wheel. The eccentricity between the. work holder and the grinding wheel results in relatively moving the pieces of work endwise' across the face the machine attendant.

of the wheel and thus distributes the wear evenly.

It may also be noted here that since the pieces of work do not set radially on the Wheel but at an angle to the radii of the wheel, as is shown in Fig. 10, the action of the grinding wheel is somewhat different from that ordinarily produced. That is, each grain of the grinding wheel which comes in contact with the work, instead of moving directly across the face of the work, has a composite movement with reference to the work which results in producing a finer surface than that made by the more common methods.

The lubricant or other liquid used to flood the work and the parts in contact therewith while the grinding operation is being performed may conveniently be supplied from a tank 156, Figs. 2 and 3. A pump 157 raises the lubricant from this tank and forces it through a pipe 158 into the presser head 27, this head being made hollow and having a series of discharge apertures, as shown in Fig.

3,-for the purpose of distributing the lubricant properly to the difl'erent points where the inding operationis takin place. This lubricant drenches the work, ows over the surface of the grinding wheel, and over the upper surfaces of the bracket 10 and base 12. The base is provided with suitable channels to catch the lubricant and conduct it to a spout 160 which returns it to the tank 156. It should be noted that the support 4, Fig. 3, for the grinding wheel is so designed that it prevents the liquid used in grinding from reaching the bearings for the shaft 5.

It will now be appreciated that this invention provides a machine which will handle a great variety of forms of round work on a production basis, while at'the same time requiring relatively little skill on the part of The machine not only is adapted to handle work in relatively large quantities, but it is also capable of producing very accurate work. Furthermore, it is highly automatic, while at the same time being so designed that wear and depreciation are reduced to a minimum.

While we have herein shown and described the best embodiment of our invention that we have so far devised, it will be evident that the inve' tion may be embodied in a great variety pf forms without departing from the spirit or scope thereof. For example, it is contemplated that the presser head 27 instead of bein made of metal, as above described, may I e made of a material having abrasive characteristics. Whether both the presser head and grinding wheel are made of abrasive material, or one only of these members has abrasive characteristics, depends on the requirements of individual machines and the nature of the work which they are required to perform, and is not material from r the standpoint of machine organization.

While the grinding wheel and prewer head are hereinafter claimed in the relationship in which they have been shown, the use of the head as an abrasive or grinding wheel, 'as above mentioned, with the Work supported on a lower wheel obviously is the equivalent of the specific arrangement shown. Cranes for moving the work holder into and out of the machine, instead of being manually operated may be arranged to be operated by power, if desired. A crane arranged to be lifted by power is shown in Fig. 13. In this arrangement, the arm 112 is constructed and mounted as above described. A cap 162 is bolted to the upper side of. the bracket from which the arm extends and is internally'bored to form a cylinder in which a stationary piston 163 is mounted. This piston is supported on the top of the post 113, ball bearings being interposed between the piston and the post. Compressed air may be admitted to the cylinder 162 or released therefrom by a manually operated three-way valve 164. It will be evident that when air under pressure is .admitted to the cylinder 162 it will lift the arm 112, together with the work holder 36 and the parts supported thereby. This work holder may then be swung into or out of the machine. Subsequently, when it is desired to lower thearm 112 it is simply necessary to move the air valve 164 into the proper position to release the air'from the cylinder 162. Various other work against said wheel, means for rotating said wheel, power driven mechanism for raising and lowering said head to move it toward or from its operating position, additional mechanism for controlling the rate of approach of said head toward said wheel, and a fluid pressure operated means arranged to be brought into action by said additional mechanism to stop the rotation of said wheel.

2. In a'grinding machine, the combination of a grinding wheel mounted to rotate in a horizontal plane, a presser head mounted above said wheel for up and down movement and operative to press the work against said wheel, means for guiding said head for vertical movement toward or from said wheel, a part connected with said head to move up and down therewith, a stop arranged to be engaged by said part, a horizontally movable wedge supporting said stop, and power driven tical movement toward or from said wheel,

' hearing against said wedge,and--power-012%;

. move said wedge in a direction'to; permit said and operative'to pre'ss thework against said v wheel, means for guiding said head for verengaged by said part, ahorizontally movengaged by said part, a-horizontally movable a direction. permitting said stop to settle 5 said interruption,

above said wheel for. up and down movement 30 and operative to pres's .,the"w0rkagainst said able wedge supporting said stop, a screw shaft bearing against said, wedge, power operated mechanism for rotating said shaft to move said wedge in 1. a direction to ermit said stop to settle gradually and t ereby 7n limit the, rate of approach ofsaid head to-" wardl'said wheel, means. for automatically in-, :terrupting the action o-f saidmechanismwhen said head has arrived at a predetermined -distance from said "wheel, andf means forresetifting said screw-shaft infitsiiiitial. position 'after's'aid interruptionfi I: f.

1 1:7; Ina grinding machine, the combination of agrinding'wheel'mountedto rotate in a horizontal plane, a presser head mounted above said wheel for up and down movement and operative to press the work against said wheL-means for guiding said head for vertical :.-n 1ovement toward :or from said "wheel, a part connected with said head to move up '85 =fand .do'wlntherewitln-a stop arranged to .be

engaged by said part, a horizontally movable Wedge supporting saidstop, a screw shaft bearing against said wedge, power operated mechanism for rotating said shaft to move said Wedge in a direction to emit said stop to settle gradually and there y limit the rate of approach of saidhead toward said wheel,

horizontal plane, a presser head mounted above said wheel for up and down movement and operative to press the work against said wheel,.means'for guiding said head for vera part connected with said head to move up and down therewith, a stop arranged to be engaged by said part, a horizontally movable wedge supporting said stop, .a screwshaft,

erated mechanism for rotating said shaft I w stop to settle gradually and therebylimit the rate of approach of said head towardgsaid wheel.

4;. In aigrinding machine, the combination of a grinding wheelmon'nted to rotate in a horizontal plane, a presser head mounted above said wheelafor paaaaxddwn movement-'- tical movementjtoward or from said wheel,- a part connected with said head to,-;,move up and down therewith, a stop 'arranged to be able wedge supporting said 'stop, power driven mechanism for slowly moving said wedge in a direction permitting said stop to settle gradually and thereby limit/the rate means for automatically interrupting the acof approach'of said head toward said wheel,..;

tiO n. of said mechanism when said head has 5 and meansfor automatically finterruptingf 1:l'arrivedat apredcterinined distance from the action of said mechanism when. said-head said hfil means forfautomatically return" has arrivedjin'a predetermined;relationship nag-saidscrew shaft its. initial position to a en 1 :s a i mpa m n pr nga orire- 1 5. In a grindingmachine, the combination {setting said wedge in its origmalposition of a grinding wheel mounted 'to rotate in a after saidinterruption; horizontal plane," apresser head mounted 8. Ina 'ndin'g machine, the combination *above said; wheel for up. and down movement of a 'grin n g wheel mounted to rotate in'a and operative to press the workagain'st said; horizontal plane, a presser head mounted wheel, meansforguiding said head for'v er above said;wheel for up and down movement tical movement towardor from said wheel; and operative to press the work against said a part connected with said head to move up wheel, means for guiding said head forverand down therewith, a stop arranged to be tical movement toward or from said wheel, a part connected with said head to move up and down therewith, a stop arranged to be 11' "engaged by said-part, a horizontally movable 'wedge supporting said stop,,a screw shaft. bearing against, said wedge, power operated mechanism forrotating said shaft to move "said wedge in a direction to emit said stop- "to settle gradually and there y limit the rate I of approach of sai'dhead toward said wheel, said mechanism including a clutch through which powerv is transmitted to said shaft, and a torsion spring arranged to be tensioned by the rotation of said shaft and operative upon the release- 0f said clutch to-automatically wedge supporting. said stop, power driven} mechanism for slowly moving said wedge in gradually and thereby-limit the rate of 'ap-- proach of said head' towardsaidj'wheel, means for automatically interrupting the action of said mechanism when saidhead has arrived in a predetermined:relationship to said wheel, and means .for automatically resetting said wedge in its initial position after 6. In a grinding machine, the combination ,of a grinding wheel mounted to rotate in a horizontal 1ane,- -ai;p esser;head: mounted return said; shaft" .to; its fini '9,- I in -1 1g w ine; of a grin wheel mminnar-v horizontal 1p ane, a Presser head mounted f above said wheel for up and down movement and operative to ,press the work against said wheel,means,for guiding said head for vertical movement toward or from said wheel, a

wheel, means for. guiding said'h'ead for vertical movement toward or from said wheel, a part connected with said head. tomove'up and down therewith, a stop'arranged'to be engaged by said part, a horizontally. mov-' part connected with said head to move up and down therewith, a stop arranged to be en gaged by said part, a horizontally movable wedge supporting said stop, a screw shaft bearing against said wedge, power operated mechanism for rotating said shaft to move said wedge in a direction to ermit said stop to settle gradually and there y limit the rate of approach of said head toward said wheel, said mechanism including a clutch through which power is transmitted to said shaft, and means operated by the rotation of said shaft through a predetermined angle for operating said clutch.

10.' In a grinding machine, the combination of a grinding wheel mounted to rotate in a horizontal plane, a presser head mounted above said Wheel for up and down movement and operative to press the work against said wheel, means for guiding said head for vertical movement toward or from said Wheel, a part connected with said head to move up and down therewith, a sto arranged to be engaged by said part, a horizontally movable wedge supporting said stop, a screw shaft bearing against said wedge, power operated mechanism for rotating said shaft to move said wedge in a direction to permit said stop to settle gradually and thereby limit the rate of approach of said head toward said wheel, said mechanism including a clutch through Which power is transmitted to said shaft, means for rotating said wheel, and means arranged to be operated by the rotation of said shaft through a predetermined angle to release said clutch and also to stop the rotation of said wheel.

11. In a grinding machine, the combination of a grinding wheel mounted to rotate in a horizont 1 plane, a presser head mounted above sald wheel and operative to press the work against said wheel, power driven mech-' anism for raising and lowering said head, a micrometer screw connected with said head to move up and down therewith, a stop arranged to be engaged by said screw, a horizontally movable wedge supporting said stop, and power driven means for slowly moving said wedge under said stop in a direction permitting the stop to descend gradually.

12. In a grinding machine, the combination of a grinding wheel mounted to rotate in a horizontal plane, a presser head mounted above said wheel and operative to press the work against said wheel, a vertical slide sup porting said head, a shaft mounted parallel to said slide, a manually controlled reversible mechanism for driving said shaft, a nut on said shaft arranged to support said slide, whereby said mechanism is operative to raise or lower said slide and head to move it from or toward operative relationship to 'said wheel, means operated by said nut for automatically interrupting the rotation of said shaft when the'nut has been moved up or down to a predetermined point, and an additional power driven mechanism including a driven member having an inclined surface for limiting the rate of downward movement of said head.

13. In a grinding machine, the combination of a grinding wheel mounted to rotate in a horizontal plane, a presser head mounted above said wheel and operative to press the Work against said wheel, means for guiding said head for vertical movement toward or from said wheel, mechanism for driving said wheel, a work holder mounted between said wheel and head, and automatic mechanism for stopping the rotation of the grinding Wheel when the Work has been reduced to a predetermined size.

14. In a grinding machine, the combination of a grinding wheel mounted to rotate in a horizontal plane, a presser head mounted above said wheel and operative to press the work against said wheel, means for guiding said head for vertical movement toward or from said wheel, mechanism for driving said wheel, a work holder mounted between said wheel and head, and means for automatically interrupting the grinding action on the work when the work has been reduced to a predetermined size.

15. In a grinding machine, the combination of a grinding wheel, a device movable up or down for pressing the work against said wheel, means for rotating said wheel, mechanism for raising and lowering said device to.

in a. substantially horizontal plane, a presser head mounted above said wheel for movement up and down relatively to the wheel and operative to press the work against said wheel, power driven mechanism for raising and lowering said head, said head being disconnectable from said mechanism and arranged to have a lowering movement independently of said mechanism, additional power driven mechanism for limiting the rate of said lowering movement of the head, said additional mechanism including a screw shaft controlling said lowering movement, and said mechanisms being operable independently of each other and at difi'erent times.

17. In a grinding machine, the combination of a grinding wheel mounted to rotate in a substantially horizontal plane, a presser head mounted above said wheel for movement up and down relatively to the wheel and operative to press the work against said. wheel, power driven mechanism for raising and lowering said head, saidhead being disconnect-- able from said mechanism and arranged to have a lowering movement independently of said mechanism, additional power driven mechanism for limiting the rate of said lowering movement of the head, said mechanisms being operable independently of each other and at different times,'and said additional mechanism including a screw shaft controlling said lowering movement, means for automatically interrupting the action of said ad ditional mechanism when said head has arrived at a predetermined distance from said wheel, and means for resetting said screw shaft in its initial position after said interruption.

18. In a grinding machine, the combination of a grinding wheel mounted to rotate in a substantially horizontal plane, a presserhead mounted above said wheel for movementup and down relatively to the wheel and operative to press the work against said wheel, power driven mechanism for raising and lowering said head, said head being disconnectable from said mechanism and arranged to have a lowering movement independently of said mechanism, additional power driven mechanism for limiting the rate of said lowering movement of the head, said mechanisms being operable independently of each other and at different times, said additional mechanism including a screw shaft for limiting the rate of said lowering movement,

a clutch through which power is transmitted to said shaft, and a spring arranged to be tensioned by the movement of said shaft and operative upon the release of said clutch to automatically return the shaft to its initial position. 1

19. In a grinding machine, the combination of a grinding wheel mounted to rotate in a substantially horizontal plane, a presser head mounted above said wheel for movement up and down relatively to the wheel and operative to press the work against said wheel, power driven mechanism for raising and lowering said head to move it toward or from its operative relationship to said wheel, said mechanism including a clutch, automatic means for throwing the clutch into its neutral position to stop the movement of said head by said mechanism, said head being disconnectable from said mechanism whereby it may be freed therefrom and permitted to move downwardly at a different rate from that limiting the downward movement of said head, and additional power driven mechanism for giving said stop a gradual lowering movement.

20. In a grinding machine, the combinacaused by said mechanism, a positive stop for tion of a grinding wheel mounted to rotate in a substantially horizontal plane, a presser head mounted above said wheel for movement up and down relatively to the wheel and operative to press the work against said wheel, power driven mechanism for raising and lowering said head to move it toward or from its operative relationship to said wheel, said mechanism including a clutch, automatic means for throwing the clutch into its neutral position to stop the movement of said head by said mechanism, said head being disconnectable from said mechanism whereby it may be freed therefrom and permitted to move downwardly at a different rate from that caused by said mechanism, a positive stop for limiting the downward movement of said head, a micrometer screw connected with said head for movement up and down therewith, said screw being arranged to engage said sto power driven mechanism for giving sai stop a gradual lowering movement, and means for automatically interrupting the action of the last mentioned power driven mechanism when the head has reached a predetermined space relationship to said wheel.

21. In a grinding machine, the combination of a grinding member mounted to rotate in a horizontal plane, a presser member for holding the work against said grinding member, one of said members being mounted above the other, means for rotating said grinding member, means for guiding the upper of said members for vertical movement under the influence of gravity toward the other member, and power driven mechanism including a wedge for controlling the rate of said movement.

22. In a grinding machine, the combination of a grinding member mounted to rotate in a horizontal plane, a presser member for holding the work against said grinding mem tion of a grinding member mounted to rotate in a horizontal plane, a presser member for holding the work against said grinding member, one of said members being mounted above the other, means for rotating said grindmgmember, means for guiding the upper of said members for vertical movement toward or from the lower member,

power driven mechanism for raising and lowbeing operable independently of each otherand at difierent times, and adjustable means for stopping said approaching movement when the upper member has reached a predetermined spaced relationship to the lower member.

24. In a grinding machine, the combination of a grinding member mounted to rotate in a horizontal-plane, a presser member for holding the work against said grinding member, one of said members being mounted above the other, means for rotating said grindin member, power driven mechanism for raising and lowering said upper member to move it toward or from its operating position, additional mechanism for controlling the rate of approach of said upper member toward said lower member, and means arranged to be brought into operation by said additional mechanism for automatically stopping the rotation of said grinding mem- In testimony whereof we have signed our names to this specification.

WILLIAM ABTER. WARREN F. FRASER.