US2053878A - Hydraulically operated grinding machine - Google Patents

Description

v WITNESS Sept. 8; 1936. H, s v 2,053,878

HYDRAULICALLY OPERATED GRINDING MACHINE Filed July 12, 1935 G m M75 46b 05 HERBERT A. S'ILVEN Patented Sept. 8, 1936 Z,053,87&

PATENT OFFICE HYDRAULICALLY OPERATED GRINDING MACHINE Herbert A. Silven, Worcester, Mass, assignor to Norton Company, Worcesten'Mass a corporation of Massachusetts I Application July 12, 1935, Serial No. 31,059

18 Claims. (Ci. 51-72) This invention relates to grinding machines, and more particularly to a work rest and wheel slide control mechanism for a hydraulically driven cylindrical grinding machine.

Heretofore, various types of hydraulic drive mechanisms have been applied to control the various moving parts of a grinding machine, namely, a longitudinal table traverse, transverse movement of wheel toward and from the work, and movement of the work steadying shoe toward and from its operating position into engagement with the work. In the previous constructions, the control of the hydraulically actuated mechanisms has been under individual and separate control, requiring the manipulation of several control levers in the operation of the machine.

In certain types of cylindrical grinding, such as the grinding of the cylindrical crankpins on a crankshaft, it is necessary for the wheel and steadyrest shoe to be removed from engagement with the work to a considerable distance to separate the wheel and work rest sufiiciently from the work to allow the longitudinal traversing movement of the table to position the next pin opposite the grinding wheel. Heretofore, to accomplish this result, it has been necessary to either manually or hydraulically move the wheel to its rearward position and then by means of a separate control remove the steadyrest shoe to its inoperative position. It has also been necessary to remove the splash guard from its operative position, so as to allow the removal of the finish ground crankshaft and the insertion of a new shaft to be ground, without. lifting the heavy shafts up and over the splash guard. Similarly, when it is desired to grind a given crankpin on a crankshaft after it has been loadedin the machine, it has been necessary for the operator to position the splash guard in its operative position and to advance the steadyrest shoe into operative engagement with the surface of the-work either manually or by the operation of a manually controlled mechanism before the wheel slide control is moved to bring the wheel into grinding relation with the work piece. Such arrangements have necessitated a considerable amount of the operators attention before and after the grinding operation.

Moreover, in such grinding machines, it has heretofore been necessary for the operator to lift the piece of work, such as a heavy crankshaft, over. the table and the steadyrest mechanism in order to get it into position on the work supporting head. The necessity of liftingthe heavy shaft up and over the ordinary types of steadyrest fatigues the operator and consequently impairs the efficiency of the machine.

It is one object of this invention to provide a wheel feed and work rest positioning mechanism which operates automatically and simul- 5 taneously to move the rest and grinding wheel either towards or from the work, in which the work rest is moved vertically into or away from an operating position.

It is a further object of this invention to provide a hydraulically actuated, vertically movable steadyrest which is adapted to be lowered to an inoperative position during the traversing of the work table or the loading of a new piece of work into the machine.

It is another object of this invention to provide a fluid pressure control valve which serves in one position to cause a simultaneous movement of the steadyrest up into an operating position and an infeeding movement of the grind- 2o ing wheel, in a second position to cause a forward or infeeding movement of the grinding wheel, and in a third position to cause the wheel slide to move rearwardly and the steadyrest to move downwardly into inoperative positions. 25

Fig. 1 is a cross-section view through a grinding machine embodying this invention, having the wheel slide and steadyrest shown in elevation;

Fig. 2 is a fragmentary end elevation partly 30 in section, on an enlarged scale, of the steadyrest and its support as shown in Fig. 1;

Fig. 3 is a fragmentary front elevation, on an enlarged scale, of the steadyrest; and

Fig. 4 is a fragmentary horizontal section taken approximately on the line 4-4 of Fig. 2.

One embodiment of this invention has been illustrated in the drawing, comprising a grinding machine having a base Ill which supports a transversely movable wheel slide ll on the usual ways l2. The wheel slide it carries a rotatable grinding wheel l3.

A longitudinally movable work supporting table I5 is slidably mount edon the base ID on the usual V-way l6 and flat way H. The table l5 may be moved longitudinally relative to the base ID by means of any of the well-known traverse mechanisms, including a rack bar 22 supported on the table l5. A gear 23 meshes with the rack 22 and is mounted on the inner end of a rotatable shaft 2 3. A manually operable traversing wheel Q is mounted on the outer end of said shaft on the front of the machine base, These parts have not been illustrated in detail, since they are not parts of the present invenvide means for rapidly moving the grinding wheel tion. For further details of such a traverse mechanism, reference may be had to the prior United States PatentNo. 762,838 to Charles H. Norton dated June 14, 1904.

The longitudinally movable table 15 serves to rotatably support a work piece, such as a crankshaft 20, in a rotatable Work holder 2| mounted on the table l5. The rotatable work holder may comprise the usual head and footstock, such as is shown in the above-mentioned prior patent, or if the mechanism is utilized in a crankpin grinding machine, the work holder or holders 2| are preferably of a double head type, that is, having a duplicate rotatable work holder 2| on each end of the table l5 which serve to grip and synchronously rotate the opposite ends of a crankshaft to be ground. For further details of such a work gripping and rotating mechanism, reference may be had to the United States Patent No. 1,837,342 to; Herbert A. Silven, et al. dated December 22, 1931.

The grinding wheel slide II is arranged for a transversefeeding movement toward and from the work piece 20. A manually operable feeding mechanism may be provided including a half nut 25 depending from the wheel slide ll meshing with a rotatable feed screw 26 which is journalled in bearings 21- and 28 in the base ID. The front end of the feed screw 26 carries a gear 29 meshing with a gear 30 which is mounted on the inner end of a rotatable shaft 3| joumalled in the base ID. The front end of the shaft 3| carries a gear 32 meshing with a gear 33 on the inner end of a. rotatable shaft 34, the outer end of which carries a manually operable hand wheel 35. It will be readily apparent from the foregoing disclosure that rotation of the hand wheel 35 in either direction causes infeeding or an outfeeding movement of the grinding wheel I3. The rotation of the hand wheel is transmitted through gear 33, gear 32, shaft 3|, gear 30,"gear 29, to rotate feed screw 26, which in turn serves to move the half nut, wheel slide and grinding wheel 13 either towardor from the work piece, depending on the direction of rotation of the hand wheel 35.

In the grinding of the crankpins on a crank shaft, it is necessary to remove the grinding wheel a considerable distance from the axis of the pin being ground in order that the crank arms, between the various crankpins will clear the periphery of the grinding wheel when the table is traversed to present the next pin into operative relation with the grinding wheel. In order to accomplish this result, namely, to pro- |3 into operative position or rearwardly to an inoperative position, a fluid pressure system is utilized comprising a cylinder 36 which is fixedly mounted on the base 10. A piston 31 is slidably mounted within the cylinder 36 and is connected by a piston rod 38 with the bearing 28 which supports one end of the feed screw 26. The bearing 28 is slidably mounted within an aperture 39 in the base Ill and is slidably keyed thereto by means of a key 40.

Fluid under pressure may be supplied to said cylinder by a fluid pressure pump 4| .which draws fluid from a reservoir or sump 42 in the base l through a pipe 43 and passes the fluid under pressure through a pipe 44 to a control valve 45. In the preferred construction, the control valve 45 serves as a single valve unit for controlling and regulating the movements of both the wheel slide II and work steadyrest hereinafter 60- scribed. The valve 45 serves in one position to admit fluid so that the grinding wheel and work rest move simultaneously toward the work and in a second position serves to admit fluid to cause the grinding wheel slide and the steadyrest to move simultaneously to inoperative positions away from the work, and in a third position serves to admit fluid only to the cylinder for causing an infeeding movement of the grinding wheel, allowing the steadyrest to remain in an -inoperative position. The control valve 45, as

illustrated, is of the slidable piston type having valve pistons 46, 41, 48, and 49 arranged on a valve stem 50 and is controlled by an operating handle or knob In order to attain one of the objects of this invention, namely, to provide a work steadying rest which may be readily and rapidly moved to an operative position in engagement with the work or into an inoperative position so that the steadyrest is out of the operators way in removing the ground crankshaft from the machine and in placing a new shaft into the machine for grinding, a steadyrest is provided which may be bodily moved to and from an operating position. In the preferred construction, a vertically positioned slideway 60 is mounted on the machine base In by means of bolts 6! which pass through elongated slots 62 in the slideway 60 and are threaded into a portion of the base If! (Figs. 3 and 4). The vertically movable slide 60 is arranged in a fixed position opposite to the periphery of the grinding wheel and is arranged to support a steadyrest frame 65 which is provided with slideways 66 which mate with the vertically movable slideway 60, so that the steadyrest frame may be readily moved in a vertical direction to move a steadyrest shoe 68 into an operating position, as shown in full lines in Fig. 2, or moved vertically into an inoperative position 68a, as indicated inbroken lines in Fig. 2. An adjustable tapered gib 63, which is held in position by screws 64, is interposed between slideway 60 and lefthand slideway 66 (Figs. 3 and 4) to compensate for wear in the slide 'parts and to maintain the slide in proper adjustment.

The steadyrest frame 65 carries a horizontally movable slide 69 which supports the work steadying shoe 68. In order that the shoe 68 may be readily adjustedtoward or from the work so as.

to maintain the shoe in proper supporting contact with the work during grinding, a nut and screw mechanism is provided including a screw I0 which is threaded into a nut H which is keyed to the steadyrest frame 65.- The inner end of the screw is provided with a head 12 which engages a T-slot 13 in and adjacent to the end of slide 69. from the front of the steadyrest frame and is provided with an adjusting knob 14. The knob 14 is threaded to mesh with the threads on screw 10 and is arranged to be clamped in a fixed position on the screw 10 by means of a clamping screw 61. It will be readily apparent that rotation of the knob I4 rotates screw 10 and causes the slide 69 to move either toward or from the work piece 20, so that the shoe 68 may be maintained inthe proper adjusted position relative to the work during the grinding operation.

In order that the steadyrest frame may be moved rapidly from its inoperative position 68a (broken line position of Figs. 1 and 2) into an operating position 68 (full line position, Figs. 1 and 2) a fluid pressure mechanism is provided including a cylinder 50 which is fixedly mounted to The outer end of screw 10 projects the base it. The cylinder 86 carries a slidably mounted piston 8i which is connected by a piston rod 32 with a projection 83 of the steadyrest frame 65. A pipe 84 is arranged to admit fiuid under pressure to a cylinder chamber 36 so as to cause the steadyrest frame 55 and shoe 68 to move upwardly, in a vertical direction, into operative relation with the work piece and grinding wheel. A

similar pipe t'l serves to admit fluid under pressure to a cylinder chamber 38 to cause a downward movement of the steadyrest frame 65 and shoe 58 from the full line position indicated in Figs. 1 and 2 into the broken line position 68a. It will thus be seen that the steadyrest may be rapidly and readily moved to and from an operating position and is arranged so that when in an inoperative position, the steadyrest frame is moved bodily downward, leaving the space between the work holders and the grinding wheel clear to the front of the machine so that the work piece may be readily removed from the holders without undue exertion on the part of the operator.

It is highly desirable that the steadyrest and the grinding wheel slide be arranged so that both may be moved simultaneously into or away from an operating position. This is preferably accom plished by arranging the fluid pressure mechanism so that fluid under pressure may be simultaneously admitted to the cylinders 36 and 80, so that the steadyrest 65 and the wheel slide I I may be simultaneously moved either toward or from the work feed. To accomplish this result, the fluid under pressure passing through the pipe 44 enters a valve chamber 90 between the valve pistons 41 and 48. In the full line position of the valve (Fig. 1), fluid from the valve chamber 90 passes simultaneously through a pipe 9|, through the pipe 84, into cylinder chamber 86, to

move the piston 8I and steadyrest frame 65 upwardly into the operating position, as illustrated in Fig. 2, and at the same time passes through a pipe 92 into a cylinder chamber 93 in the cylinder 36 to cause the wheel slide II to move forward into the position illustrated in Fig. 2.

The control valve 45 is arranged so that it may be positioned in any one of three positions, namely, the full line position as indicated in Fig. 2, in which a spring pressed plunger 95 engages a notch 96 in the valve stem 50. If it is desired to move only the grinding wheel slide l I toward the work, the operator moves thecontrol knob 50 inwardly until a notch 91 in the. valve stem 50 is engaged by the plunger 95. In this position of the valve, the valve pistons assume the positions illustrated in dotted lines 460., 41a, 48a, and 49a, and fluid under pressure from the pipe 44 is admitted into valve chamber 90 and passes outwardly only through pipe 92 into the cylinder chamber 93 in the cylinder 36 to cause the grinding wheel slide H to rapidly approach its operating position.

After the work has been ground to a desired size, it is desirable to remove the grinding wheel and the steadyrest from operative engagement with the work rapidly and return them to their inoperative positions. This is accomplished by moving the control knob 5| toward the right, as viewed in Fig. 1, until the notch 98 is engaged by plunger 96. In this position of the valve, the valve pistons assume the dotted line positions as indicated, 46b, 41b, 48b, and 49b, in which position fluid from pipe 44 entering valve chamber 90 passes outwardly through a pipe I and pipe IIlI to admit fluid through a pipe 81 into the cylinder chamber 88 to cause the steadyrest to move downwardly into an inoperative position and at the same time admits fluid from pipe M0 through a pipe Hi2 into a cylinder chamber I03 in cylinder 36 to cause the wheel slide to move rearwardly into an inoperative position.

The fluid pressure system is provided with the usual relief or by-pass valve E which is connected by a pipe N36 with the pressure pipe line '64, so that if the pressure builds up within the guard to prevent the splashing of coolant fluid and grit toward the front of the machine onto the operator and the floor. The splash guard may be automatically removed to prevent obstructing the insertion of work into or taking it out of the machine. Such a splash guard'is provided which operates automatically when the steadyrest is moved to and from an operative position. In the preferred form, as illustrated in the drawing, the

splash guard is made in two parts, each of which is separately pivoted to the steadyrest frame 65.

An upper splash guard H0 is pivotally mounted on a pair of opposed screws I I I on the steadyrest frame 65. A lower splash guard H2 is pivotally mounted on the steadyrest frame by means of a pair of screws II3 (only one of which is shown). The lower end of the lower guard is provided with a rounded edge portion I I4 which rides on the upper surfaceil5 of, the table I5. The lower end of the upper guard I I0 is similarly provided with a rounded portion II6 which rides on the front face of the lower guard H2. These parts are so arranged that when the steadyrest is moved downwardly into an inoperative position, the portion N4 of the lower guard H2 rides down the surface N5 of the table, rocking the lower guard l I2 about its pivot screws I I3. At the same time,

the lower end N6 of upper guard III] slides down the face of the lower guard II 2 until the two guards are moved into the inoperative positions l 80a and i 52a, as shown in broken lines in Fig. 2.

It will be readily apparent from the disclosure and description above that when the steadyrest 65 is moved vertically into an operating position, due to the pivoting of the guards, the force of gravity holds the upper guard down against the lower guard which in turn holds the lower guard against the upper surface of the table so that the splash guard is automatically swung into an operating position to prevent the splash of coolant fluid onto the operator or onto the floor in front of the machine. Similarly, on'the downward movement of the rest, the guard is automatically swung into an inoperative position, allowing removal of the finish ground work piece and insertion of a new piece of work to be ground without thenecessity of manually removing the splash guard or lifting the heavy crankshaft up and over the guard.

The operation of this mechanism is readily apparent from the foregoing disclosure. Assuming the parts to be in the position illustrated in Fig.2, the grinding wheel is grinding the work and the steady rest shoe 68 is in operative position opposite to the grinding wheel, supporting and steadying the work during the grinding operation. The steadyrest shoe 68 is maintained in proper adjusted position by means of the knob 14. When the work piece has been ground to a predetermined size, the operator shifts the knob 50 to change the position of the control valve 45, moving the valve toward the right as viewed in Fig. 1 until notch 98 is engaged by the plunger 95, which serves to admit fluid under pressure through pipe 44, valve chamber 90,

through pipe I00, and simultaneously through pipes llll and I02 to simultaneously cause the steadyrest 65 to move downwardly to an inoperative position 68a, the splash guards H0 and H2 to move to inoperative positions Him and 2a, and the wheel slide H to move rearwardly to an inoperative position.

The crankshaft 20 may then be readily removed from the machine Without the necessity of reaching up and over the splash guard and steadyrest frame, andreplaced with a new shaft to be ground. Then, if desired, the operator may shift the control knob 50 from the position with the notch 98 in engagement with plunger 95 into a position where notch 91. engages plunger 95 so as to admit'fluid under pressure from valve chamber 90 only through pipe 92 to cause the grinding wheel to be moved into an operative position adjacent to the surface of the work. As

the wheel approaches the work, the operator may by manipulation of the work table traverse wheel 9 to adjust the longitudinal position of the crankpin relative to the grinding wheel so as to split the spark, that is, so that the grinding wheel is centered relative to the cheeks or side faces adjacent the ends of the crankpins. When the spark has been split, the operator may then move knob 59 so that notch 96 is engaged by the pin 95, in whichposition fluid is then admitted from valve chamber 90 through pipe 91 to move the steadyrest upwardly in a vertical direction into the full line position, as indicated in Figs. 1 and 2. The grinding operation then proceeds by the operator turning the hand feed wheel 35 to feed the grinding wheel into the work and at the same time adjusting the knob 14 so as to maintain the steadyrest shoe 68 in proper supporting position in engagement with the work during the grinding operation. If desired, the

fluid pressure mechanism for operating the wheel slide as well as the cylinder for operating the steadyrest shoe may be arranged so that the fluid under pressure passing into these two cylinders serves to give the necessary feeding movement to the grinding wheel and to the steadyrest so as to maintain the steadyrest shoe 65 in the desired contact with the work and also to cause the desired infeeding movement of the grinding wheel l3.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A grinding .machine comprising a base, a rotable grinding wheel, a transversely movable slide to support said wheel, a longitudinally movable work supporting table, a rotatable work supporting mechanism on' said table, a slidesupporting mechanism on said table, a slideway on said base, a vertically movable work rest supported by said slideway which is arranged to be moved to and from an operating position, and means to simultaneously move the steadyrest vertically and the grinding wheel into either an operative or inoperative position.

3. A grinding machine comprising a base, a rotatable grinding wheel, a transversely movable wheel slide, a longitudinally movable work supporting table, a rotatable work support thereon, a steadyrest frame, a vertically movable slide to support said frame, a steadyrest shoe on said frame, manually adjustable means to adjust the shoe horizontally to maintain the shoe in operative contact with and to support the work during grinding, and means to move the steadyrest frame in a vertical direction into either an operative or an inoperative position.

4. A steadyrest for a grinding machine having a base comprising a vertically movable slideway on said base, a steadyrest frame having ways mating with said vertical slideway, a horizontally adjustable steadyrest shoe mounted on said steadyrest frame, manually operable means to adjust the position of said shoe, and means to move said steadyrest frame rapidly either toward or from an operating position.

5. A steadyrest for a cylindrical grinding machine having a base, a vertical slideway on said base, a steadyrest frame having ways arranged to mate with said vertical slide, a horizontally movable steadyrest shoe mounted on said frame, manual means to adjust said steadyrest shoe toward or from. the work, and a fluid pressure system including a piston and cylinder interposed between said steadyrest frame and vertical slide to move the steadyrest frame to an from an operating position.

6. A steadyrest for a cylindrical grinding machine comprising a vertically arranged slideway, a vertically movable steadyrest frame having slideways mating with said vertical slideway, a steadyrest shoe adjustably mounted on said frame, manually operable means to adjust the position of said shoe to maintain it in supporting contact with the work piece as it is reduced in size during grinding, and a fluid pressure system including a piston and cylinder interposed between the slideway and steadyrest frame, which serves to move the steadyrest frame bodily in a vertical direction into an operating position or to withdraw the steadyrest frame to an inoperative position.

7. A steadyrest for a grinding machine having a base, a vertically movable slideway on said base, a vertically movable steadyrest frame having ways mating with said slideway, a steadyrest shoe adjustably mounted on said steadyrest frame, a manually operable nut and screw mechanism to adjust the position of said shoe relative to said frame, and means including a fluid pressure piston and cylinder interposed between the slideway and steadyrest frame, and a control valve to move said steadyrest frame vertically into'an operative position in engagement with the work or to lower the steadyrest to an inoperative position.

8. A-grinding machine having a base, a rotatable grinding wheel, a transversely movable wheel slide to support said wheel, a longitudinally movable work supporting table, a rotatable work support on said table, means to traverse said table longitudinally, means to'adjust the position of the wheel relative to the work to feed the wheel into the work, a vertical slideway on said base, a steadyrest frame slidably supported in said slideway, and means to move said steadyrest frame vertically within said slide to and from an operating position.

9. A grinding machine having a base, a rotatable grinding wheel, a transversely movable wheel slide to support said wheel, a longitudinally movable work supporting table, a rotatable work supreduced in size during grinding, and a fluid pressure means including a cylinder and piston operatively connected to move said frame vertically within said slideway to and from an operating position so that the steadyrest frame may be moved to an inoperative position when the machine is.

being loaded. a

10. A grinding machine having a base, a rotatable grinding wheel, a transversely movable wheel slide to support said wheel, a longitudinally movable work supporting table, a rotatable work ,support on said table, means to traverse said table longitudinally, means to adjust the position of the' wheel relative to the work to feed the wheel into the work, a vertically arranged slideway on said base, a steadyrest frame slidably supported in said slideway, a horizontally movable shoe supported on said frame, manually operable means to ad-.

just the shoe so as to maintain the shoe in an operating position supporting the work piece as .it is reduced in size during grinding, and a fluid pressure means including a piston and cylinder operatively connected to move said frame vertically to and from an operating position so that the steadyrest frame and shoe may be lowered to an inoperative position when the machine is being loaded.

11. A grinding machine having a base, a rotatable grinding wheel, a transversely movable wheel slide to support said wheel, a longitudinally movable work supporting table, a rotatable work support on said table, means to traverse said table longitudinally, a fluid pressure means including a piston and cylinder to move said slide rapidly to and from an operating position, manual means to adjust the position of the wheel relative to the work to feed the wheel into the work, a vertical slideway on said base, a steadyrest frame slidably supported in said slideway, a horizontally movable shoe supported on said frame, manually operable means to adjust the shoe so as to maintain the shoe in an operating position supporting the work piece as it is reduced in size during grinding, and a fluid pressure means including a piston and cylinder operatively connected to move said steadyrest frame vertically to and from an operating position so that the steadyrest frame may be lowered to an inoperative position when the machine is being loaded.

12. A grinding machine comprising a base, a rotatable grinding'wheel, atransversely movable wheel slide on said base, a longitudinally movable work table on said base, a rotatable work support on said table, means to traverse said table longitudinally to position the work piece relative to the grinding wheel, means to feed said wheel toward and from the work to grind the work piece to a predetermined size, means including a fluid pressure piston and cylinder to move said slide rapidly either toward or from an operative position, a steadyrest which is movable vertically to and from an operating position, a vertical slideway on said base to slidably support said steadyrest, means including a fluid pressure piston and cylinder operatively connected to move said steadyrest to an operating position, and means including a control valve which serves in one position to simultaneously admit fluid to both of said cylinders to cause a simultaneous approaching movement of the wheel relative to the work and a vertical movement of the steadyrest.

13. A grinding machine comprising a base, a rotatable grinding wheel, a transversely movable wheel slide on said base, a longitudinally movable work table on said base, a rotatable work support on said table, means to traverse said table longitudinally to position the work relative to the grinding wheel, manual means to feed the wheel toward and from the work to grind the work piece to a predetermined size, means including a fluid pressure piston and cylinder to move said slide rapidly either toward or from an operating position, a steadyrest which is movable vertically to and from an operating position, a vertical slideway on said base to slidablysupport said steadyrest, means including a fluid pressure piston and cylinder operatively connected between said steadyrest and base to move said rest to and from an operating position, and a fluid pressure system including a control valve which is arranged to simultaneously admit fluid under pressure to both of said cylinders to simultaneously move the steadyrest downwardly and wheel slide to an inoperative position.

14; A grinding machine comprising a base, a rotatable grinding wheel, a transversely movable wheel slide on said base, a longitudinally movable work table on said base, a rotatable work support on said table, means to traverse said table longitudinally to position the work piece relative to the grinding wheel, manual means to feed said slide toward and from the work to grind the work piece to a predetermined size, means including a fluid pressure piston and cylinder to move said slide rapidly either toward or from an operative position, a steadyrest which is movable vertically to and from an operating position, a vertical slideway on said base to slidably support said steadyrest, means including a fluid pressure piston and cylinder operatively connected between the steadyrest and base to move said steadyrest to and from an operating position, and means including a control valve which serves in one position to admit fluid to said first cylinder and cause a forward positioning movement of the grinding wheel, in a second position to simultaneously admit fluid to each of said cylinders and cause a simultaneous approaching movement of the wheel and steadyrest, and in a third position to admit fluid to simultaneously admit fluid to each of said cylinders and cause a simultaneous withdrawal of the wheel and steadyrest to their inoperative positions.

15. A grinding machine comprising a base. a longitudinally movable work table, a rotatable work support thereon, a transversely movable wheel slide, a rotatable grinding wheel thereon, a vertically movable slideway on said base, a steadyrest frame having guideways mating with said vertical slideway, a horizontally movable steadyrest shoe on said frame, manual means to adjust the positionof saidshoerelatively toward.

- work support thereon, a transversely movable wheel slide, a rotatable grinding wheel thereon, a vertically movable slideway on said base, a steadyrest frame having guideways mating with said vertical slideway, a horizontally movable steadyrest shoe on said frame, manual means to adjust the position of said shoe relatively toward and from the work to steady the same during grinding, and a splash guard pivotally mounted on said steadyrest frame and having its lower edge rounded and supported on the upper surface of said table which is arranged to be moved to an inoperative position when the steadyrest frame is lowered to an inoperative position.

17. A steadyrest and splash guard for a grindlng machine having a base and a longitudinally movable work table comprising a vertically movable slideway on said base, a steadyrest frame having ways mating with said vertical slideway, a horizontally adjustable shoe mounted on said steadyrestframe, manually operable means to adjust the position of said shoe, means to move said steadyrest frame rapidly either toward or from an operating position, and a two-part splash guard, each part of which is pivotally supported to said steadyrest frame, the'lower guard having a rounded edge portion which is slidably the table.

supported on said table, said upper guard having a rounded lower edge portion resting by gravity on the lower guard, said upper and lower splash guards being so arranged as to rock to an inoperative position when the steadyrest is lowered to an inoperative position.

18. A grinding machine comprising a base, a longitudinally movable work table, a rotatable work support 'thereon, a transversely movable wheel slide, a rotatable grinding wheel thereon, a vertically movable slideway on said base, a steadyrest frame having guideways mating with said vertical slideway, a horizontally movable steadyrest shoe on said frame, manual means to adjust the position of said shoe relatively toward and from the work to steady the same during grinding, means to move said steadyrest frame vertically to and from an operating position, and a two-part splash guard including a lower guard member having its upper edge pivotally mounted on said steadyrest frame and its lower edge rounded and resting upon the upper surface of said table, an upper guard member which is pivotally mounted on said steadyrest frame and having a rounded lower edge portion resting by gravity 'on the surface of said lower guard member, said upper and lower guard members being arranged so that when the steadyrest frame is moved vertically downward to an inoperative position, the lower guard slides down the upper surface of the table so that the upper and lower guards are rocked in a counterclockwise direction to an inoperative position above and a jacent to HERBERT A. SILVEN.

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