US2082728A - Grinding machine - Google Patents

Description

June I 1937..

w. H. WOOD 2,082,728

GRINDING MACHINE Filed June 6, 1956 3mm WALLACE H. W001) Patented June 1, 1937 UNITED sTATEs v aowizs GRINDING MACHINE Wallace :1. Wood, Worcester, llllml' to Norton Company, Worcester, Ma... a corporation of Massachuset Application June 6,1936, 8...... it... $3.91: a

Claim.

This invention relates to grinding machines, and more particularly to a fluid pressure operated wheel feeding mechanism.

One object of this invention is to provide a 5 simple and thoroughly practical hydraulically operated wheel feeding mechanism for a grinding machine. Another object of this invention is to provide a suitable wheel feed control mechanism so that the infeeding movement of the grinding wheel may be precisely controlled so as to grind a work piece to a predetermined size. Another object of this invention is to. provide a fluid pressure wheel feed control which enables a precise regulation of the infeeding movement and also the dwell after the infeeding movement has stopped. Other objects will be in part obvious or in part pointed out hereinafter.

This invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing in which is shown one of various possible embodiments of the mechanical features of this invention, p

The figure is an end view of a grinding machine, having parts broken away and shown in section to more clearly show the operating construction.

A grinding machine has been illustrated in the drawing comprising a base it which supports a transversely movable wheel slide H which is mounted on transversely extending ways (not shown). The wheel slide ii supports a rotatable grinding wheel i2 which is mounted on the end of a rotatable wheel spindle E3. The wheel spindle it may be driven by any of the well-known driving mechanisms, such as an overhead belt drive J shown), each of which is provided with work supporting centers to rotatably support a work piece 2 I in operative relation with the grinding wheel l2.

The table il may be traversed longitudinally by a manually operable traverse mechanism which includes a rack bar depending from the of a rotatable shaft 21.

' (01. si-"osi under side of the table II. The rack bar 25 meshes with a gear 26 supported on the inner end A manually operable traverse wheel 2! is mounted on the outer end of the shaft 21 and is arranged to be manually 5 rotated to traverse the table II longitudinally relative to the base l0. If desired, a power operated traversing or reciprocating mechanism may be provided, such as for example a mechanism of the type shown in the expired U. S. patent to Norton No. 762,838 dated June 14, 1904.

A wheel feeding-mechanism is provided for manually feeding the grinding wheel toward and from the work, which comprises a half nut depending from the wheel slide II. The half nut 35 meshes with or engages a rotatable cross feed screw 36. A forwardly extending portion 31 of the cross feed screw 36 is slidably keyed to a rotatable sleeve 38. The rotatable sleeve 38 is formed as an integral part of a rotatable shaft, 20 which is iournaled in bearings 39 and 40 in the base it. A manually operable feed wheel Ill is mounted on the forward end of a stud $2. The stud 32 carries a pinion 43 which meshes with a gear M mounted on the outer end of the sleeve shaft 38 so that a manual rotation of the feed wheel ti serves to rotate the feed screw in either direction to cause a forward or rearward feeding movement of the grinding wheel i2 and wheel slide i i. The feed wheel M may be provided with a micrometer adjusting mechanism d5 which is substantially identical with that shown in the above-mentioned prior patent to Norton. This micrometer mechanism serves to precisely adjust the stop on the manual infeed to compensate for wheel wear.

In the preferred construction, the wheel slide Ii is arranged so that it may be moved toward and from the "work piece to grind the same to a predetermined size by means of a fluid pressure actuated wheel feeding mechanism. As illustrated in the drawing, the rear end of the feed screw 36 is rotatably supported in a slidably keyed bearing which is supported in a casing M on the base of the machine. A fluid pressure cyl inder 491s attached to the casing 5i and contains a slidably mounted piston 52 which is connected by a piston rod 53 with the bearing 50 and is arranged so that when fluid under pressure is admitted to a cylinder chamber 54, the piston 52- 50 will be moved into its rearward position, as illustrated in the drawing, transmitting a corresponding movement through the feed screw 36, the half nut 35, to move the wheel slide l I and the grinding wheel I! rearwardly to an inoperative posi- 55 tion. Similarly, when fluid under pressure is admitted to a cylinder chamber 55, the wheel slide II and grinding wheel I2 are caused to move in a forward direction to move the grinding wheel I2 5 toward the work piece 2| for a grinding operation. When fluid is admitted either to the cylinder chamber 54 or the cylinder chamber 55, a rapid approaching or receding movement of the wheel I2 and wheel slide II is provided.

It. is desirable to provide a suitable fluid pressure controlling or feed regulating mechanism for modifying the rapid approaching movement caused by the piston 52 to obtain a controlled and predetermined feeding movement of the i5 grinding wheel. In the preferred construction,

a self-contained dash pot feed regulator is provided comprising a pair of dash pot cylinders 55 and 51 which contain dash pot pistons 58 and 59 respectively. The dash pot pistons 58 and 59 and their respective cylinders 55 and 51 are arranged with their axes parallel to each other and spaced on diametrically opposite sides of the piston rod 53. The dash pot pistons 58 and 59 are normally held in a rearward position by means of springs 52 and 93 serve to respectively limit the rearward movement of the dash pot pistons 58 and 58.

The forward rapid feeding movement of the wheel I2 and wheel slide II continues until an adjustable sleeve 55, which is adjustably supported on the rear portion of the piston rod 53, engages the ends of the dash pot pistons 58 and 59 respectively, after which the rapid approaching movement of the wheel I2 and slide II, as produced by the piston 52, is reduced to a slower predetermined grinding feed due to the fact that fluid confined within the dash pot cylinders 55 and 51, which are interconnected, exhausts fluid through a passage 56, a needle valve 51, into a reservoir 68 contained within the dash pot casing. By adjusting the aperture of the needle valve 51, a desired and predetermined infeed may be obtained. a

When fluid under pressure is admitted to the cylinder chamber 54 to cause a rearward movement of the piston 52, the sleeve 55 moves rearwardly and the released tension of the springs 68 and 6| serves to return the dash pot pistons 58 and 59 respectively to the rearward position, as illustrated in the drawing. During the rear ward movement of the dash pot pistons 59 and 59, a suction is created within the dash pot cylinders 56 and 51 respectively which serves to aid in drawing fluid from the reservoir 68, through a pipe 59 and a ball check valve 18, to fill the dash pot chambers 56 and 51 to fill the chambers for the next infeeding operation. During the infeeding movement of the dash pot pistons 58 and 59, the fluid within the dash pots 56 and 51 serves to hold the ball check valve 18 closed so that fluid within the dash pot cylinders 59 and 51 is forced out through the passage 58 and the needle valve 61 into the reservoir 58 to control the infeeding movement, as desired.

A fluid pressure system is provided to convey fluid under pressure to the cylinder 49. This system may comprise a reservoir 15 which is m located preferably within the.base of the machine and from which fluid is pumped by a geared pump 16, through a pipe 11, and through a pipe 18, to a control valve 19. The control valve 19 is of a balanced piston type comprising '5 a valve stem 88 having formed integrally there- 68 and BI respectively. Adjustable stop screws on valve pistons BI, 82, 83 and 84. The front end of the valve stem 88 is provided with a spool shaped member 85 which is connected by a stud 85 with a pivotally mounted lever 81. The lever 81 is pivotally supported on a stud 88 which is supported on a bracket 89 on the base I8 of the machine. A manually operable control lever 98 is also pivotally mounted on the stud 88 and is connected to move the lever 81 when the manually operable lever is shifted to change the position of the control valve 19, as desired.

In the position of the parts, as illustrated in the drawing, the valve stem 88 is in its rearward position so that fluid under pressure passing through the pipe 18 enters a valve chamber 9I between the valve pistons 82 and 83 and passes through a passage 92, into cylinder chamber 54, to move the piston 52 rearwardly to withdraw the slide II and grinding wheel I2 from operative engagement with the work piece 2i. During this movement, fluid is exhausted from the cylinder chamber 55, through a passage 93, through a valve chamber 94 between the valve pistons 82 and I, and a pipe 95 which exhausts into the reservoir 15.

When the control lever 98 is moved in a counterclockwise direction, that is moved forwardly, the control valve 19 is shifted into a reverse position so that fluid under pressure passing through the pipe 18 and the valve chamber 9I passes through the passage 93, into cylinder chamber 55, to cause a forward feeding movement of the piston 52, the wheel slide. II and the grinding wheel I2. During the forward feeding movement, fluid is exhausted from the cylinder chamber 54, through the passage 92, into a valve chamber 96 between the valve pistons 83 and 84 and out through the pipe 95 into the reservoir 15.

The infeeding movement of the grinding wheel under the control of the dash pot pistons 58 and 59 respectively continues until an adjustable stop sleeve 98 carried on the adjustable sleeve 65, which is in turn supported on the piston rod 53, engages a stop surface 99 on the end of the dash pot casing, thereby positively limiting or stopping the forward advancing movement of the wheel slide II and the grinding wheel I2.

It is desirable to provide a feed and dwell control mechanism which enables a precise adjustment of the final infeeding movement of the grinding wheel as well as to precisely control the extent of the dwell or finish grinding dwell, sparking-out or flnish grinding period. In the preferred construction, a displacement cylinder is provided which serves to precisely regulate the exhaust of fluid from the dash pot cylinders 56 and 51 to control the infeed of the grinding wheel. When the dash pot pistons have been rendered ineffective by the stop sleeve 98 engaging the stop surface 99, the continued displacement of fluid within the displacement cylinder serves to control a dwell or sparking out or finish grinding period to accurately size the work to the required extent. As illustrated in the drawing, a displacement cylinder I88 is connected and when moved in the reverse direction serves to displace fluid within the cylinder I00 at a controlled rate. The displacement rod I00 may be moved by a suitable power operated mechanism. such as, for example, a fluid pressure operated piston I04 which '18 slidablymounted within the cylinder I05. The admission oiiiuid under pressure to the cylinder I05 may be coninfeedi'rig trolled independent of the hydraulic mechanism above described.

In the preferred construction, the cylinder I05] is arranged so that the piston I04 and the dis-'- placement rod I03 move in the same direction as the main piston rod 53 and is preferably ooh trolled by the control valve II so that" the piston I04 moves in the same directionas, and; in a definite timed relationship with, the wheel" feed piston 52.

of the parts, as illustrated in the drawing; fluid to move the piston ioltowar'd the right intdthe" position illustrated in the drawing; a Dorih jtiie 2" movement of the piston I04 toward the rig'ht; 1 fluid is exhausted from the cylinder chamber I01, through a pipe H5, into the valve chamber;

94 and out through the pipe 95, into the refs; J"

When the reversing valve I9 is shiitedint'ojits reverse position so that fiuid under pressure with in the valve chamber 0| passes through the pass; sage 00 to cause a forward approaching mov'e- .ment of the piston 02, fluid under pressure also In the preferred construction, the movemen'ftgof;

the piston I00 toward the left is preferably ate.

controlled rate so that the movement of the disthe pipe M0, and closes the ball check'vai'vei and an adjustable throttle valve III and through through the pipe 9%, into the reservoir.i5.

the pipe I001 into the valve chamber 96.1 andout A dwell control mechanism'is prdyide l as, f uiating and controlling the extent of the spark ing-out or finish grinding time after j the stop sleeve 08 engages the stop surface '90. This mechanism comprises a normally open mercury slwltcli- I whichis carried by a supporting bracket I2I pivotally mounted on a stud I2 2 on a bracket! fixed to the base It of the machine. Trie nial-cury switch I20 is connected to the power lines i2t.,

A solenoid I20 is connected in theelectricallicir-f.

cuit in series with the normally oph mercury switch I20. The solenoid I is cohnficted by a link us with a stud m on the arm .0l' andjis arranged so that when the mercury switch II IITis rocked in a counterclockwise direction. the. circuit is closed to energize the solenoid I25 thereby;

shifting the lever 0'1? and the lever-90in a clo'ckf. wise direction into the position illustratedin-the drawing to shift the valve stem 80 otthe control valve 19 so as to reverse the flow oigfluidf-within.

The cylinder I05 -isprovided with f cylinder chambers I00 and'IOI. In the position the system and cause a rearward movement of the grinding wheel I2 and the wheel slide II.

In order to control the movement of the mercury switch I20, a fluid pressure mechanism is provided which is preferably connected with the displacement cylinder I00. This mechanism comraises a cylinder Ihaving a piston IIII slidably mounted therein. A pipe .l32 connects the cylinder I80- with'the displacement cylinder I00. A spring'iifl serves to normally; hold the piston I3I infth'eposition illustrated in the drawing. The spring I" is preferably interposed between a casing' I34 and a bracket I35 which is fixed to the end of the piston m. An adjustable stop screw I34, in the casing I04 servesto limit the movement or the piston I3! toward the left, as viewed in the. drawing.

In order to'actuate the mercury switch I20 intimed relation with the movement of the piston III, an adiustable detent I40 is mounted on the piston .br'acke't I35. The detent I40 is arranged to engagea pivotallymounted detent III which is piv tauy mounted on the stud I22. A downwardly' extending projection of the pivotally mounted detent lfilisarranged in the path of the detent I40 so' that' when the detent I40 is moved on the stud I22 and transmits no movement ercury $W'ItchI20. When thedetent m d'by piston ISI "in a direction toward the ugh to iiliistiat'd in Fig. 1, the

detehjt I se strihihg' the downwardly extending hit 99 bratket I21. andfthe 'mercury"switch I20 in a counterclockwise direction, tipping the switch I20 and closing the'circ'uit' so'as to energize the solenoid'ififi an'd shift the lever ill, the lever 90, togetherwith thevalve I0, into-the position illus-' trotted inl the drawing.

Th e first portiofn of the dash pot movement, while fluid may exhaust through passage to, servesto produce acontrolled infeed to grind a shouldenon the workpiece 2i, and the displacement cylinder Ito together with the mercury switch I20 and its associated parts serves to controlt he finaligrinding operation as well as the dwell orspark'ing-out period at the end of the grinding 'operation; g

In the operation ofthis improved wheel feeding mechanism; the work piece II is mounted in placeinthe machine, the work is rotated and the grinding: wheel is rotated at a grinding speed.

Assuming the feed mechanism to have been previously to thedesired extent to obtain the desired 'ihfeeding movement, the manually operablej'contrfol lever 90 is moved in a counterclockvg ise'jdirectiongi as shown in Fig. 1, to shiftthe valve stem 00'soIas to reverse the how of fluid in themech'anism. The valve-I0 is shifte'dso that 'fiuidund'er pressure from pump it passing throtugfipipe it into valve chamber-9i passes out through '93 into-cylinder chamber 55 to rapid'i'approaching movement of the slide II. arid the-grinding wheel It toward the work. Th iirapid approaching movement of the grindwheel continues until the sleeve 65 carried bythe piston rod 03 engages the ends of the dash pot pistons ht andffid and continued movement ofthe piston-021s. modified to produce a slow shoulder feed in which the fluid is exhausted from the dash pot. chambers to and 0? through passage I and needle-valve BI into the reservoir 68., At

the. same time. when the pistons '58 and 50 are picked up by the sleeve 00. fluid from the dash pot cylinders-00 and W is forced'through pipe IOI into the displacement cylinder I and through the pipe I32 into cylinder I30 to move the piston I3I toward the. left, as viewed in the drawing, against the tension of the spring I33 5 until the piston I3I engages the stop screw I38. During this movement of the piston I3I, thede-v tent I40 rides idly by the detent I4I so as to render the dwell control mechanism operative.

During the forward movement of the slide II lo'and grinding wheel I2, when the piston 52 starts moving fluid under pressure is also admitted from the valve I9, through pipe Iii, into the cylinder chamber I0'I, to cause a movement of the piston I04 and the displacement rod I03 toward the left, as viewed in the drawing, as controlled by the aperture of the throttle valve II2. After the passage 66 is cut off, fluid from the dash pot chambers 50 and 51 may be forced only through the pipe IOI, as permitted by the controlled movement of the displacement rod I03 which serves to increase the fluid capacity of the cylinder I00 and atthe same time fluid being forced through the pipe IOI serves to hold the piston I3I in a position toward the left. This controlled infeeding movement for grinding the cylindrical portion of the work continues until the adjustable stop sleeve 98 engages the stop surface 99, thereby preventing further displacement of fluid within the dash pot cylinders 56 and 51. The displacement rod I03 continues to move toward the left and due to the compression of the spring I33, fluid within the cylinder I30 is forcedthrough the pipe I32 into the displacement cylinder I00, as permitted by the 35 withdrawal of the displacement rod I03. This movement continues until the detent I engages the depending projection of the detent I as the piston I3I moves toward the right and rocks the bracket I2I and the mercury switch I20 in 40 a counterclockwise direction to make the circuit,

thereby energizing the solenoid I25. The energizing of the solenoid I25 serves to move the lever 81 in a clockwise direction, thereby shifting the piston rod 30 and valve I9 into the position of the parts illustrated in the drawing so as to admit fluid under pressure from the valve chamber 9I, through passage 92, into the cylinder chamber 54 to cause a rapid rearward movement of the grinding wheel I2 and the wheel slide ll.

When the valve I9 is shifted to reverse the movement of the piston 52, fluid under pressure also passes through the pipe I03, ball check valve I09, pipe I I0, into cylinder chamber I06, to cause 55 the piston I04 and the displacement rod I03 to move toward the right. This movement displaces fluid within the displacement cylinder I00, passing it through the pipe IN and into the dash pot cylinders 59 and 51 so that exhaust of 30 fluid through the pipe MI and fluid passing through the pipe 69 and ball check I0 serves to flll the dash pot chambers 56 and 51 so that they are ready for the next infeed grinding operation.

The operation of the feed mechanism above described provides a shoulder grinding feed. In case it is desired to grind work requiring no shoulder grinding feed, the needle valve 61 may be closed so as to prevent escapement of fluid from the dash pot pistons 56 and 51 through the 70 passage 66 and needle valve 61 into the reservoir 68. In this case, when the adjustable sleeve 65 picks up and moves the dash pot pistons 58 and 59, fluid within the dash pot chambers 50 and 51 is forced out through the pipe IOI into the displacement cylinder I00. The initial movement of fluid through the pipe IOI into the displacement cylinder I00 passes through the pipe I32 into the cylinder I30 to move the piston I3I against the spring I33 so that the detent I40 is moved into a position for a dwell control operation. The infeeding movement continues at a controlled rate due to the controlled movement of the displacement rod I03 until the sleeve 93 engages the stop surface 99, thereby preventing further forcing of fluid from the dash pot cylinders 50 and 01 through the pipe IOI. As the rod continues its movement toward the left, the compression of the spring I33 moves the piston I3I toward the right., .This movement continues until the detent I40 engages the downwardly extending projection of the detent Hi to rock the mercury switch I20 so as to energize the solenoid I25 and thereby shift the reverse valve I0 into its reverse position to cause a rapid movement of the grinding wheel I2 to an inoperative position.

It will thus be seen that there has been provided by this invention apparatus in which the various objects herelnabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

' I claim:-

1. A grinding wheel feeding mechanism for a grinding machine having a rotatable work support and a rotatable grinding wheel which are movable longitudinally and transversely relative to each other, a transversely movable slide to support one of said elements for movement toward and from the other, a fluid pressure piston and cylinder operatively connected to move said slide and cause a rapid relative movement of the wheel and work supports toward and from each other, and a wheel feed regulating mechanism for a grinding machine comprising a fluid pressure displacement cylinder, a displacement rod slidably mounted therein to increase or decrease the fluid capacity of said cylinder, and a power operated means positively to ,move said displacement rod in either direction.

2. A grinding wheel feeding mechanism for a grinding machine having a rotatable work support and a rotatable grinding wheel which are movable longitudinally and transversely relative to each other, a transversely movable slide to support one of said elements for movement toward and from the other, a fluid pressure piston and cylinder operatively connected to move said slide and cause a rapid relative movement of the wheel and work support toward and from each other, and a wheel feed regulating mechanism for a grinding machine comprising a mud pressure displacement cylinder, a displacement rod slidably mounted therein to increase or decrease the fluid capacity of said cylinder, power operated means positively to move said displacement rod in either direction, and means to regulate the speed of movement of said rod in one direction to control the infeeding movement of a grinding wheel.

3. A grinding wheel feeding'mechanism for a grinding machine having a rotatable work support and a rotatable grinding wheel which are movable longitudinally and transversely relative to each other, a transversely movable slide to support one of said elements for movement toward and from the other, a fluid pressure piston and cylinder operativeiy connected to move said slide and cause a rapid relative movement of the wheel and work support toward and from each other, and a wheel feed regulating mechanism for a grinding machine comprising a fluid pressure displacement cylinder, a displacement rod slidably mounted therein to increase or decrease the 10 fluid capacity of said cylinder, and fluid pressure operated means including a piston and cylinder operatively connected to move said displacement rod at a controlled rate in either direction.

5 d. A grinding wheel feeding mechanism for a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, a fluid pressure piston and cylinder operatively connected to move said slide and wheel rapidly 20 toward and from the work, and a wheel feed regulating mechanism for a grinding machine comprising a fluid pressure displacement cylinder, a displacement rod slidably mounted therein to increase or decrease the fluid capacity of said 25 cylinder, means including a fluid pressure operated piston and cylinder to move said displacement rod in either direction at a controlled rate, and means including a control valve to admit fluid under pressure to either end of said cylinder.

5. A grinding wheel feeding mechanism for a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, a

fluid pressure piston and cylinder operatively connected to move said slide and wheel rapidly 35 toward and from the work, and a grinding wheel feed regulating mechanism for a grinding machine comprising a dash pot piston and cylinder which are arranged to control the grinding infeed, a displacement cylinder, fluid connections therebetween, a displacement rod slidably mounted within said displacement cylinder, and means to withdraw said rod from said displacement cylinder at a controlled rate to permit a controlled displacement of fluid from the dash pot cylinder.

6. A grinding wheel feeding mechanism for a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, a

fluid pressure piston and cylinder operatively connected to move said slide and wheel rapidly toward and from the work, and a grinding wheel feed regulating mechanism for a grinding machine comprising a dash pot piston and cylinder arranged to control the grinding infeed, a displacement cylinder, fluid connections therebetween, a displacement rod slidably mounted within said displacement cylinder, and means including a fluid pressure operated piston and cylinder to withdraw said rod from said displacement cylinder at a controlled rate to permit a controlled displacement of fluid from the dash pot cylinder.

7. A grinding wheel feeding mechanism for a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, a

5 fluid pressure piston and cylinder operatively connected to move said slide and wheel rapidly toward and from the work, and a grinding wheel teed regulating mechanism for a grinding machine comprising a dash pot piston and cylinder 7 arranged to control the grinding infeed, a displacement cylinder, a displacementrod which is slidably mounted within said displacement cylinder, means including a fluid pressure operated piston and cylinder to move said displacement rod 75 in either direction, and a control valve to conslide and cause a rapid relative movement of the wheel and work support toward and from each other, a control valve to control the admission of fluid to said cylinder, and a wheel feed regulator comprising a dash pot piston and cylinder which are arranged to modify the movement of said piston and cylinder, means including a displacement cylinder operatively connected with the dash pot cylinder, a displacement rod within said cylinder, means to withdraw said displacement rod to allow displacement of fluid from said dash pot cylinder, and means to regulate the speed of movement of said displacement rod to facilitate adjustment of the displacement of fluid from said dash pot to control the infeeding movement of the grindingwheel.

9. A grinding wheel feeding mechanism for a grinding machine having a rotatable grinding wheel and a transversely movable wheel slide, a fluid pressure mechanism comprising a piston and cylinder operatively connected to move said slide and grinding wheel rapidly either toward or from a work piece, and a wheel feed regulator including a dash pot piston and cylinder which is arranged to reduce the rapid approaching movement of the slide to a slow controlled infeeding movement, a displacement cylinder operatively connected with the dash pot cylinder, a displacement rod slidably mounted within said cylinder, and means to move said displacement red at a controlled rate to control the displacement of fluid from said dash pot so as to control the infeeding movement of the grinding wheel.

10. A wheel feeding mechanlsm'ior a grinding machine having a rotatable grinding wheel, a transversely movable slide to support said wheel, means including a fluid pressure piston and cylinder to move said slide rapidly in either direction, a fluid pressure feed regulator to modify said rapid movement in one direction, a feed regulator and dwell control mechanism associated therewith including a displacement cylinder having a slidable displacement rod therein, said displacement cylinder being connected to receive the exhaust of fluid from said feed regulator, means to move said displacement rod at a controlled rate in either direction to regulate the speed of movement of the grinding wheel, and means including an electric switch actuated in timed relation with the movement of the displacement rod to automatically cause a rearward movement of the slide after a predetermined period of dwell.

11. A grinding wheel feeding mechanism for a grinding machine having a rotatable grinding .wheel, a transversely movable wheel slide, a fluid pressure system including a piston and cylinder to move said slide, a control valve to admit fluid to either end of said cylinder to cause a rapid forward or rearward feeding movement of the grinding wheel, manual means to actuate said valve, a solenoid to shift said valve to cause a rapid rearward movement of said wheel, and a wheel feed regulator which is arranged to modify the movement of said piston including a dis placement cylinder and a movable displacement rod to regulate the exhaust oi fluid from said feed regulator, means to move said rod in either direction so as to control the fluid exhausted from said regulator and thereby control the infeeding movement of the grinding wheel, an adjustable stop mechanism to positively limit the forward feeding movement of the grinding wheel, a normally open electric switch which is normally in an open position, and means actuated in timed relation with the movement of said displacement rod to actuate said switch and thereby energize said solenoid to reverse the control valve after a predetermined period of dwell.

12. A grinding wheel feeding mechanism for a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, a fluid pressure piston and cylinder operatively connected to move said slide and wheel rapidly toward and from the work, and a wheel feed regulating mechanism for grinding machines comprising a fluid pressure displacement cylinder, a displacement rod which is slidable therein to increase or decrease the fluid capacity of said cylinder, means including a fluid pressure piston and cylinder to move said displacement rod in either direction, a control valve to admit fluid under pressure to either end oi. said cylinder, a manually operable lever to move said valve in either direction, a solenoid to shift said valve to cause a rearward movement of the grinding wheel, a throttle valve in said system to control the speed of movement of the displacement rod in one direction, an electric switch, and fluid pressure means actuated in timed relation with movement of said rod to actuate said switch so as to energize the solenoid and reverse said valve to cause a rapid rearward movement of the grinding wheel.

13. A wheel feed regulating mechanism for a grinding machine having a transversely movable rotatable grinding wheel comprising a fluid pressure displacement cylinder, a displacement rod which is slidably mounted therein and arranged to increase or decrease the fluid capacity of said cylinder, means including a fluid pressure piston and cylinder to move said displacement rod in either direction, a control valve to admit fluid to either end of said cylinder, a throttle valve in said system to control the speed of movement of the displacement rod in one direction to control the infeeding movement oi! the grinding wheel.

14. A wheelieed regulating mechanism for a grinding machine comprising a fluid pressure displacement cylinder, a displacement rod which is slidably mounted therein and arranged to increase or decrease'the fluid capacity of said cylinder, means including a fluid pressure piston and cylinder to move said displacement rod in either direction, a control valve to admit fluid to either end of said cylinder, a manually operable lever to move said valve in either direction, a solenoid to'shiit said valve to cause movement of the Diston, a throttle valve in said system to control the speed of movement of the displacement rod in one direction, an electric switch, and fluid pressure means actuated in timed relation with the movement of said displacement rod to close said switch and energize said solenoid to reverse the control valve after a predetermined period of dwell.

15. A grinding wheel feeding mechanism for a grinding machine having a rotatable work support and a rotatable grinding wheel which are movable longitudinally and transversely relative to each other, a transversely movable slide to support one of said elements for movement toward and from the other, a fluid pressure piston and cylinder operatively connected to move said slide and cause a rapid relative movement of the wheel and work support toward and from each other, a control valve to admit fluid to either end of said cylinder to cause a rapid forward and rearward ieeding movement of the grinding wheel, manual means to actuate said valve, means including a solenoid to shift said valve to cause a rapid separating movement of said slide, a feed regulator which is arranged to modify the feeding movement of said piston including a displacement cylinder and a movable displacement rod to regulate the exhaust of fluid from said feed regulator, means to move said rod in either direction so as to control the exhaust of fluid therefrom and control the infeeding movement between the grinding wheel and work support, an adjustable stop mechanism to positively limit the infeeding movement, means including a hydraulically actuated electric switch, and means actuated after the positive stop has been reached to displace fluid within said latter mechanism toactuate said switch after a predetermined period of dwell and operate said solenoid to reverse the valve and cause a rapid separating movement between the wheel and work.

WALLACE H. WOOD.

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