US2284325A - Honing machine - Google Patents

Description

May 26, 1942. J. E. KI INE HONING MACHINE Filed Nov. 27, 1939 5 Sheets-Sheet 2 IN VEN TOR Y ah) Z474).

y 26, 1942- J. E; KLINE HONING MACHINE Filed Nov. 27, 1939 5 Sh'sets-Sheet 3 J E. KLINE HONING MACHINE Filed Nov. 27, 1939 5 Sheets-Sheet 4 m M. w

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' ATTORNEY5.

May 26, 1942.

J. E. KLINE HONING MACHINE 5 Sheets-Sheet 5 Filed Nov. 27, 19:59

[NVENOR I J 5? 97i 24. A TTORNE Y5.

Patented May 26, 1942 UNITED STATES PATENT OFFICE HONING momma John E. Kline, Grosse Pointe Farms, Mich., as-

signor to Micromatic Hone Corporation, Detroit, Mich., a corporation of Michigan Application November 27, 1939, Serial No. 306,208 10 Claims. '(Cl; 51-34 This invention relates to grinding or honing machines, and especially to mechanism for individually and collectively controlling the abrading tools of a multiple spindle machine.

The principal object of the invention is to improve the art of grinding machines.

It is also an object of the invention to provide control means for each abrading tool of a multiple spindle machine for causing such tool to effect operation for which it is set andthen to cause contraction of the abrading head of each tool upon completion of such operation.

A further object is to provide individual control means for each abrading tool of a multiple spindle machine which renders each tool effective until the predetermined operation for that tool has been completed, and then retracts all of the abrading tools when the desired operations have been efiected.

Another object is to provide each abrading tool of a multiple spindle machine with a working expansion limiting means for maintaining each tool effective until full limit expansion operation for which it has been set is completed, in conjunction with control means for retracting all tools when all operations for which the tools are preset have been effected, and further, to provide each tool with manually adjustable positive stop expansion limiting means effective as a safety I stop for limiting expansion of the tool to a slightly greater amount in the event that the working expansion limiting means fails to operate.

Other objects, features, and advantages become apparent from the following description and appended claims.

For the purpose of illustrating the genus of the invention, a typical concrete embodiment is depicted in the accompanying drawings, 'in' which: Figure 1 is a perspective view of a multiple spindle grinding machine constructed in accordance with the principles of this invention;

Fig. 2 is aside elevation of one of the tool spindles which engages a centering and guiding bracket;

Fig.3 is an enlarged side elevation with parts broken away and shown in section of'the upper portion of one of the tool spindles depicted in through drive and control means of one of the spindles depicted in Fig. 1, and associated parts being shown in elevation orin partial section;

Fig. 7 is a diagrammatic view illustrating the control system for the multiple spindle'grinding machine depicted in Fig. 1;

Fig. 8 is a central vertical section of parts shown at the lower end of Fig. 3, the section being taken at approximately right angles to the partial section shown in Fig. '3; and,

Fig. 9 is an enlarged diagrammatic illustration of switch mechanism shown in Fig. .7.

Referring especially to Fig. 1 of the drawings, there is illustrated a workpiece in the form of an engine block l0, having a plurality of cylinder bores II which are to be ground, honed, or polished, such workpiece being indicative of any multiple cylinder block of a gas engine, steam engine, compressor, or similar apparatus adapted to be held in stationary position on an appropriate support of the machine illustrated and by any suitable fastening means, not shown. The abrading machine comprises an upright column I2 terminating at its upper end in a main housing l3 and having auxiliary housings l4 and I5 extending forwardly for housing spindle drive mechanism. Journalled in a reciprocating head or carriage l6 are a plurality of spindles [1, each comprising a driving portion 20, manually adjustable expansion stop means 2|, and an abrading head 22. A guiding bracket 23, preferably integrally built into the work holding fixture for the workpiece I0, is provided for centering and guiding the aiorading tools into the bores II of workpiece Ill. An hydraulic cylinder 24 is disposed between the auxiliary housings l4 and I5 for moving the reciprocating carriage or head It toward and away from the workpiece for the purpose of moving the abrading tools into and out of the bores II of such workpiece I0.

Reference may now be had to Figs. 2 to 5 and 8, in which the numeral 25 represents the body of the head portion 22 of the abrading tool and such body is provided with an axial bore 26, a plurality of radial longitudinally extending grooves 21 extending through the body 25. A double cone expander 28 is axially movable within the bore 26 and makes a two-point contact at points 30 with stone holder 3|, each'of the holders 3| carrying a stone 32 provided with end clips'and -maintained in assembled relation with respect to the stone holder by means of bands or garter springs 33. The pitch of the double coneexpander is beyond the angle of reversibility, allowing the expansion mechanism to advance the =tapered orirregular bores. The upper end of the body 25 is externally threaded and secured by means of a rocker connection to the shank 34: The rocker connection comprises a threaded sleeve 25, lock nut 36, a socket ring 31, and ball and socket portions 38 formed on shank 34 and body 25. The upper end of the double cone 28 is connected by means of a universal joint 48 to a spindle 4|. The rocker connection between the shank 34 and the body 25, in conjunction with the universal joint 48, permits uniform transfer of expansion pressure to the abrading tool and compensates for slight misalignment of the work ,with relation to the axis of the machine spindle.

Referring more especially to Figs. 3 and 8, the upper end of the spindle 4| is depicted asthreadedly connected to a holder 42 for a pin 43 which projects through the slot 44 of the shank 34 and into an adjusting sleeve 45. The sleeve 45 is externally threaded and threadedly engages a knurled adjusting nut 46. The nut 46 supports a sleeve 41 through anti-friction members 48. A ball 58 is biased upwardly into one of a series of apertures inthe lower end of the sleeve 41 by springs 5| retained by studs 52 for locking the 30 anism individual to and'designed for effecting nut 46 against accidental rotation. The antifriction members 48 are maintained in position by a sleeve 53 pinned to the sleeve 41 by pins 54.

A pin 55 fixed to the sleeve 41 extends through a slot 56 provided in the shank 34,'the gap between the pin 55 and the base portion of the slot 56 constituting the safety positive stop limiting means for regulating theexpansion of the abrading tool in the event of failure of the'working expansion limiting means, later described, to function. 1

The stop gap may be adjusted by rotating the knurled adjusting nut 46 which, due to its threaded engagement with the adjustment sleeve 45, opens or closes the gap between the lower surface of the pin 55 and the bottom of the slot 56. Such positive stop expansion limiting means of the abrading tool is intended to be set slightly beyond theworking stop limiting means, to be explained later, and to be employed only as a safety means to prevent grinding or honing-a cylindrical opening materially oversize. The upper bore of-the shank 34 is enlarged slightly to provide a shoulder 51 adapted to support the lower end of a recoil spring 68, the upper end of which abuts a pin 55 to effect contraction of the abrading tool head when compression on the expanding me'an's, later described, is relaxed.

The driver 20 of the abrading tool includes a universal joint 6| and is connected'to the upper end of the shank 34, by a pin 62 adapted to be maintained in assembled relation with respect to unit, indicated generally at 2|. A slot 81 is cut through the drive shaft push rod 66 to permit axial movement of the latter without interference with the pin 62.

Referring more specifically to Figs. 3, 4, 5, and '1, the shank 34 is provided with one, while the body 25 is provided with a plurality, of longitudinally extended passages l8, three such passages being illustrated in the body 25, leadingto a corresponding number of outlet nozzles l3 extending radially outwardly from the approximately longitudinal center ofthe body 25 and spaced equidistantly about its periphery. These nozzles extend outwardly lesser distances thanthat of the normal extension of the stones 32. The passage 18 opens outwardly through the shank 34 .to an annular recess 23 which is arranged to register with a similar recess 33' in a collar 49 rotatably journaled on the shank between the driver 28' and the adjusting unit 2|. A spacer collar 58 fixed to the shank 34 between the'collar 43 and the sleeve 41 of adjusting unit 2|, maintains the collar in the desired position axially of the tool spindle and the recesses 28 and 38 in registry. A fitting 68 .and a flexible conduit 68 lead from the registering recesses 23 and'33 for purposes described hereinafter.

Reference may now be had to Figure 6, which illustrates the fluid pressure responsive mechexpansion of each abrading tool, and further depicts control means for such fluid pressure responsive mechanism and the rotating guide mechanism for each tool spindle. Each abrading tool is rotatably driven by means of a gear 18, keyed at 1| to a drive shaft 12, which is journalled by means of thrust bearings 14 to the reciprocating carriage or head l6. The gears 18 are driven from spindle drive mechanism housed within the auxiliary housings I 4 and i5 of the abrading machine illustrated in Fig. 1. The gear sleeve '12 isthreaded at its lower end and clamped to the driver 28 by means of the clamping sleeve 15 which threadedly engages the lower end of the driver and shank 34 by a sleeve 63 which is H the double cone expander 28 through the adjustment mechanism included in the adjusting gear sleeve 12. Cylindrical bores 16 are provided in the upper portion of the reciprocating carriage or head l6 in axial alignment with the axes of each of the tool spindles. A piston 11 is disposed in each of the cylinders 16 and is provided with a downwardly and axially extending stem 18 adapted to transmit pressure from the fluid compression chamber 88, which lies between the piston 11 and the closed or blind end of the cylinder 16, to the upper end of the push rod 65 for the purpose of expanding the abrading tool 22. Each piston stem 18 is provided with an'enlarged portion 8|, projecting through a stufllng box 82 which seals and closes the lower end of its cyl inder 16. This arrangement also provides a fluid pressure expansion chamber 83 between the smiling box 82 and the lower end of the piston 11, so that when fluid pressure within the latter chamber exceeds that in the fiuid pressure chamber", the piston 11 will elevate and allow the recoil spring 60 (Fig. 3), to collapse the head 22 of the abrading tool. A solenoid operated valve,

indicated generally at 84 in Fig. 6, controls the admission of fluid pressure to the compression.

chambers 86 and 83 disposed at opposite ends of each piston 11. Each valve 84 comprises a cylindrical casing provided with a central bore 86, which in turn is provided with five substantially equally spaced annular grooves 81. A return passage 88 connects the extreme right and left hand annular grooves 81 with each other, but

communicates with none of the other annular passages 81. A return conduit 90 leads from the bore 88 will be in communication with each other,

and the centrally arranged annular grooves 81 will be in communication with the next adjacent annular ,grooves on the first-mentioned end.

As illustrated in Fig. 6, the plunger 9| is moved to its extreme left-hand position with the left-- -hand piston 92 closing communication between 1 the adjacent grooves at the left-hand end of the bore 86, and with the next to left-hand groove 81 in communication with the central grooves 81,

while the right-hand piston 92 closes the central groove 81 with respect to the next right-hand groove 81 and the latter groove isin communication with theextreme right-hand groove 81. A conduit 93 communicates with the nextto lefthand annular groove 81 and with the fluid p'ressurechamber 80 while a conduit 94 communicates with the next to right-hand annular groove 81 and the fluid pressure chamber 83. A pressure supply conduit 95 communicates between the pressure fluid source and the central annular groove 81. Thus, with the plunger 9| in the position indicated, pressure fluid will flow from the conduit 95 through the central annular groove 81 to the next left-hand annular groove 81, and

through the conduit 93 to the fluid pressure chamber 80, and force the piston 11 downwardly to expand the abrading tool. At this time, the left-hand piston 92 cuts 'ofi communication between the left-hand groove 81 and the next to left-hand groove 81, so that there will be flow between the pressure supply and the return line,

and the right-handpiston cuts ofi communication between the central annular groove 81 and the next hight-hand annular groove- The latter annular groove, however, is in open communication with a right-hand annulargroove 81 and the return passage 88, so that pressure chamber 83 will be in communication'through the conduit 94 and the return passage 84 with the return line 90. Movement of the'plunger 9| to the extreme. right-hand position will place compression chamber 83 in communication with the pressure supply 1 conduits 95 and the pressure chamber 80 incom- -munication with return line 90. This will effect elevation of the piston 11 and allow the recoil spring 80, indicated in Fig. 2, to cause contraction of the head of the abrading tool.

, Solenoids 96 and 91 are provided at the right and left-hand ends, respectively, of valve 84, asindicated in Figs. 6 and 7, and in the illustrated. position, solenoid 91 is energized while solenoid I -98 is in de-energized condition and pressure supply conduit 95 is in communication with pressure chamber 80 to effect expansion of the abrading tool. r p

The working expansion limiting means for each abrading tool is controlled-by. apressure T responsive means 13 and amicro switch I05.

away from the micro switch I05, is arranged rocating carriage or head I8, and. is provided with a, stem I02 which projects through a threaded adjusting plug I03, the latter being maintained in adjusted position by virtue of its threaded engagement with the cylinder 98. The plug I03 is adapted to be adjusted to regulate the force exerted upon the plunger I00 by the spring I 0|, ,so that the latter, at the proper time, operates the micro switch I05 when the piston 11 has descended the proper amount to i effect the desired expansion of the abrading tool.

Reference may now be had to Figs. 7 and 9 which depict a control system for the reciprocating carriage I6 and the six abrading tool spindles carried thereby. As indicated in Fig. 7, a micro switch I 05 is provided for each of the tool spindles and each micro switch I05 controls the operation of a piston 11 through a solenoid operated valve 84, but a single piston and solenoid operated valve being illustrated. Fig. 9 illustrates diagrammatically the two "left-hand micro switches I05 and the extreme right-hand micro switch I 05 shown in Fig. 7; Each of the switches I 05 includes a pair of stationary contacts I95 and I01 mounted on a base plate I08, and adapted to be contacted by a terminal contact IIO carried by a snap spring conductor ,I I I, which normally maintains the contact H0 in engagement with the stationary contact I06. The snap spring conductors III are all connected by conductors I58 to a power line I I3 leading to a suitable source of electrical energy, not

' A plunger I00 of the pressure responsive means v .13, normally biased by means of a spring IOI shown. Another power line II 2 leads to one terminal of each of the solenoids and '91 of each solenoid. operated valve 84. The stationary contacts I06 are connected by conductors II4 to the remaining terminals of the solenoids 91 while. the stationary contacts I01 are connected by means of conductor II5 to the remaining terminals of solenoids 96. .A stationary contact H6 is mounted on each switch board I 08 of theinicro switches I05 and is adapted to be engaged by a contact I I1 carried by the snap spring conductor III when the terminal contact IIOengages the stationary contact I01.

-II1 are insulated by means o'f'dielectricpads II8 frdm the snap spring conductors III; The contacts II1 of the extreme right-hand micro switch I05 is connected by means of a conductor I20 to one'terminal of the winding or solenoid I2I, the remaining, terminals of the coil of solenoid I2! being connected by means of a conductor i22 to power line H2. The stationary contacts II 6, except for that of the left-hand switch I 05, are each connected to the contacts II1 of the next connector switch to the left, as viewed in Figs. 7 and 9, The contact H6 of the left-handmicro switch I05, as viewed in Figs. '7 and 9, is connected by means of a connector I23 with the power line II3. Each micro switch I 05 is operated by a switch actuating plunger I24 provided with two insulated pegs I25 and these plung'ers are-adapted to be actuatedloy springs I38 to snap the spring conductor III to the left, as viewed in Figs. 7 and 9, in order to break contact between the terminal contacts I I0 and stationary contacts I08 and cause the terminal con tacts H0 to engage the stationary contacts I01 and also at the same time to cause the contacts III to engage the stationary contacts I I6.

As indicated in Fig. 7, the solenoid I2I is adapted to operate a valve I26, which controls the admission of fluid under pressure to either end of the cylinder 24 for lowering or elevating thereciprocating carriage or head I6. It is noted that the solenoid I2I is energized only when allof the micro switches I26 have operated to snap the spring conductors III to the left-hand position, as viewed in Figs. 7 and 9. Such left-hand position is indicated by the broken line position of snap spring conductor III of the extreme lefthand' switch, as indicated in Fig. 9. This closes the circuit from the power line II2, to the coil of solenoid I2I, conductor I20,contacts II! and H6 of all of the micro switches, and conductor I23, completing the circuit to the other power line I I3.

Energization of the solenoid I2I causes it to opcrate the valve I26, so that the hydrauliccylinder 24 will elevate the reciprocating carriage or head I6 to remove the abrading tools from the workpiece and guide bracket 28. The valve I26 may be operated in the opposite direction by duit I32 leads from the pressure conduits 95 at a point between the pump I30 and the solenoid operated valves 64 to the control valve I26 for hydraulic cylinder 24. A-return line I33 leads fromthe fiuid pressure line I32 back to the tank I3I, and a pressure regulator I34 may be'interposed in this return line for regulating the pressure of the fluid supply to the control valve I26. A pressure regulator I35 may also be interposed in the pressure conduit 95 between the pump I30 and the solenoid operated valve 64, the return conduit I36 leading from the pressure regulator I35, to'

the return conduit 90. A motor I31, or other suitable driving means, is provided for operating the pump I30.

Air is supplied at a comparatively high but constant pressure through a conduit I40 to supply air under pressure to the pressure responsive means I3 and through the flexible conduit 69, fitting 66, androtatably journalled collar 49, to the longitudinal passage I6 in shank 34 and nozzles I9 of the passage I6 in the body 25. The air may be supplied. to the conduits I40 by any suitable source of supply, not shown, high air pressures being employed since these are susceptible to comparatively close pressure regulation. A pressure reducing valve I is interposed'in the conduit I40 and just beyondthe pressure reduction valve I4 I a pressure gauge I42 is provided for indicating the reduced pressure. A volume control valve I43 is interposed in the conduit I40 and this is followed by a pressure gauge I44 to indicate the pressure to which theair has been reduced after passing through both the pressure reducing valve I and the volume control valve During operation of the abrading machine, the

tool spindles "are rotated through gears 10 .and the spindle drive mechanism contained within the housing I4 and, I5. Fluid under pressure, supplied from the tank I3I by means of pump I30, acts through the control valve I26, solenoid I2I being deenergized atthis time, to lower the spindle head I6 and lower the tool spindles I1 through the/ guiding bracket 23 to the bores II of workpiece I0. Fluid under pressure is also supplied from the pump I30 through the pressure conduit 95 to the solenoid operated valves 64 and conduits 33 to the pressure chambers 60 for each of the tool expanding pistons II in order to effect expansion of the abrading tool head 22. At this time, all of the micro switches I05 are in the positions indicated in Fig. 7 and in the full line positions indicated in Fig. 9 with the solenoids 91 energized and the solenoid operated valves in the positions indicated in Fig. 6. The solenoids 91 are energized by the electrical circuit including the power line II2, the coil of solenoid 91, conductors-H4, stationary contacts I06, terminal contacts IIO, the snap spring conductors III, and conductors I56 which lead to the power .line. I I3. Fluid pressure within the pressure chambers 60 forces pistons I1 downwardly until each abrading tool head 22 has been expanded to the working limit for which the pressure responsive means 13 has been set. The pressure responsive means 13 is set by adjusting the spring tension of spring IOI by means of the screwthreaded plug I03. 'The spring III can force the piston I00 to the left, as viewed in Fig. 6, only when the air pressure supplied through the conduit I40 and through the pressure reducing valve I and volume control valve I43 drops sufllciently to permit the spring III to move the piston I00 to the left asviewed in Fig. 6. It is noted that the air pressure supplied to the left-hand end of piston I00, asviewed in Figs. 6 and 7, is vented only at the nozzles I9 in the tool head 25. As the cutting stone 32 increases the diameter of the cylindrical opening in the work piece I0, the clearance increases between the ends of the nozzles I9 and the bores of the cylindrical openings of the workpiece. When such clearance has reached a predetermined value, a greater amount of air escapes through the nozzles I9, through passages I3. collar 49, fittings 66 and flexible conduit 69 than is admitted through the volume control valve I43 thus causing a pressure drop upon the left-hand end of the piston I00, as-viewed in Figs. 6 and 7, so that the spring IOI can move the piston III to the left and permit snapswitch I05 to operate.

In each snapswitch I05, the spring I33 causes the slide bar I24 to follow the movement of the piston I00 of the pressure responsive means 13 associated with that snapswitch. As soon as the pressure has dropped sufliciently at the left end .of piston I00 of the pressure responsive means I3, movement of the piston to the left will allow the springs I38 of the associated snapswitch I05 to move the slide bar I24 to the left, as viewed in Fig. 9, so that a peg I 25 on the slide bar I24 will force an intermediate portion of the snap spring conductor II I past the dead center of pivot centers H9 and cause the snapswitch to assume the position indicated in broken lines. It is noted in this connection that the pegs I25 engage the snap spring conductors I I I at a point spaced farther fromthe lower pivot center I I9 than from the upper pivot center H9, as indimeans to operate said valve and reverse-the action of the tool expanding and contracting maintain the terminal contacts flrmly in engagement with the stationary contacts I06 until the snap spring conductors have been-so thrown beyond dead center and throw the snap spring switches to the position indicated by broken lines at the left-hand side of Fig. 9. When a micro switch has been operated from the full line position to dotted line position, contact is broken between the stationary contact I06 and terminal contacts IIO which severs the circuit for the coil of solenoid 01 thus de-energizing the solenoid. The micro switches I are operated individually switch has enlarged its respective work bore sufliciently to provide ,the predetermined clearance between the nozzles I9 and the bore of the cylinder cut in the workpiece thus causing a suflicient venting in the air pressure system to permit the pressure responsive means 13, individual to the abrading tool, to cause its piston I00 to move sufficiently to the left so that its associated micro switch I05 will operate. Operation of a micro switch brings the terminal'contact IIO into engagement with stationary contacts I01 in order to energize the solenoid 90 through the power circuit including the power line IIZ, the coil of solenoid 96, conductors II5, stationary contacts I01 snap spring conductor III, and conductor 50 to the power line II3. As soon as all of the micro switches I25 have been thrown to the left-hand positions, broken line positions indicated in Fig. 9, the circuit is closed between the power line H3 through the conductor I23 of the extreme left-hand micro switch I05 to the contact III which at this time engages the stationary contact II6 of that switch and thence through all of the'contacts III and IIS of the other switches to the conductor I20, and then through the winding of the solenoid III to the power line IIZ. f This efiects energization of solenoid I2I and reverses the action of the control 1 valve I26 causing the hydraulic cylinder 24 to ',;}.elevate the spindle head I6. vEnergization'of the solenoid 96 has in the meantime caused fluid pressure delivered fromthe pump I30 through the solenoid operated valves 84 and conduit 94 to the pressure chamber 03 to elevate the piston "in order to causecontraction of the tool heads .23 prior to their withdrawal from the borev II of workpiece I0. v i Asmany changes could be made'in the above described construction, and many apparently widely .difierent embodiments of this invention could-be, had without departing from the spirit and scope thereof, it is intended that all matter contained in theabove description or shown in the accompanying drawings shall-be interpreted as illustrativeand not in a limiting sense. .What-,is claimed is: c 1. In a grinding or honing machine, in combination, a reciprocating tool support, means for reciprocating, said support, a spindle journalled atone end in. said support and carrying at-its otherend an expansible and contractible abrading tool, means for rotating said tool, means for expanding and contracting the abrading tool, fluid pressure responsive means for controlling the operation of said tool expanding and contracting means, avalve for reversing the action 01' the'toolexpanding and contracting means and a source of pressure fluid communicating as-soon as the abrading tool associated with each means.

2. In a grinding or honing machine, in combination, a reciprocating tool support, means for reciprocating said support, a spindle journalled at one end in said support and carrying at its other I end an expansible and contractible abrading tool, means for rotating said tool, means for expandingand contracting the abrading tool, fluid pressure responsive means forcontrolling the operation ofsaid tool expanding and contracting means, a plurality of discharge nozzles in the periphery of said abrading tool, and a source of pressure fluid communicating with'said whereby a pressuredrop occurring as a result of a predetermined amount of clearance between the nozzles in the abrading tool and the bore of the workpiece cut by the abrading tool causes the pressure responsive means to limit the expanding action of the tool expanding and contracting means.

. other end an expansible and contractible abrading tool, means for rotating said tool, means:for

with said fluid pressure responsive means and expanding and contracting the abrading tool, fluid pressure responsive means for controlling theoperation of said tool expanding and contracting means, a plurality of discharge nozzles in the periphery of said abrading tool, a substantially constant pressure' source of pressure fluid communicating with saidpressure responsive means and with said discharge nozzles, and pressure reducing means interposed between said source and said pressure. responsive means whereby a predetermined pressure drop. at the nozzles causes the pressure responsive means to limit the expanding action of the tool expanding and contracting'means.

4. In a grinding or honingmachine, in combination, a reciprocation tool support, means for reciprocating said support, a spindle journalled at one end in said supportand carrying at its other end an expansible and contractible abrading tool, meansfor rotating said tool, means for expanding and contracting the abrading tool, fluid pressure responsive means for controlling the operation of said 'tool expanding and contracting means, a plurality of discharge nozzles in-the periphery of said abrading tool,-a substantially constant pressure source of pressure fluid communicating with said pressure responsive means and with said discharge nozzles, and

a plurality of pressure reducing vmeansinter posed in series between said source and said pressure responsive means, wherebya predetermined pressure drop at the nozzlescauses the pressure responsive means to limit the expanding action of the tool expanding and contracting means. r

'5. In a grinding or honing machine, in .com-

- bination, a reciprocation tool support, a spindle journalled at one end in said support and adapt-1 ed to carry at its other end an expansible and contractible abrading tool, tool adjusting means on said support including expansible and contractible fluid pressure responsive means for expanding and contracting the-abrading tool, a

source of pressure fluid for said fluid pressure responsive means, valve means ,for directing pressure fluid from said source selectively into either pressure responsive means and with said'discharge nozzles,

end of said fluid pressure'responsive means selectively to expand or contract the abrading tool,

a second sourcelof pressure fluid, a second pressure. responsive means communicating with said second source of pressure fluid, and a vent means in said abrading tool communicating with said second source of fluid pressure whereby a predetermined drop in the pressure applied to said second fluid pressure responsive means causes the operation ofsaid valve means. 6. In a grinding or honing machine, in combination, a reciprocation tool support, a spindle V .Journalled on-one end of said support and adapted to carry on its other end an expansible and contractible abrading tool, tool adjusting means on said support including an expansible and convtractible fluid pressure responsive means for expanding and contracting the abrading tool, and

source of pressure fluid for such fluid pressure plied to said second fluid pressure responsive means causes the latter to reverse the operation of said valve means.

'7. In a grinding or honing machine, in combination, a reciprocating tool support, a spindle journalled at one end on said support andadapted to carry on its other end an expansible and and contracting 'each' abrading tool. the source of fluid pressure for all of said fluid pressure responsive means, a valve means for each of of said pressure fluid whereby a predetermined drop in the pressure applied to the said second contractible abrading tool, tool adjusting means on said support including a hydraulic cylinder, a piston in said cylinder, ,means operable by said piston for expanding and contracting the abrading tool, a source of pressure fluid for said cylinder, valve means tor directing the pressure fluid from said source into either end of said cylinder selectively to expand or contract the abradins tool, a second source of pressure fluid, a second pressure responsive means individual to that tool causes the said responsive means to reverse the operation of the valve means individual to that tool. I

9. In a grinding or honing machine for finishing a plurality of cylindrical surfaces in a workpiece, a reciprocating tool support, means for moving said support toward and away from the workpiece, a plurality of spindles each journalled at one end on said support and adapted to carry on its other end an cxpansible and contractible abrading tool, a tool adjusting means on each tool on said support including expansible and contractible fluid pressure responsive means for expanding and contracting each abrading tool, a source of pressure fluid for all of 'saidfluid pressure responsive means, a valve means for each of said fluid pressure responsive means for directing pressure fluid from said source selectively into either end of each of said pressure responsive means to expand or contract one of the abrading tools, a second source of pressure fluid, a second pressure responsive means individual to each tool and communicating with said second source of pressure fluid, vent means in each abrading tool communicating with the said second source of pressure fluid whereby a prepressure responsive means communicating with said second source "of pressure fluid, and a vent means in said abrading tool communicating with saidsecondsource of fluid pressure whereby a predetermined drop in the pressure applied to said second fluid pressure responsive means causes the said second pressure responsive means to operate said valve means and cause it to reverse.

8. In a grinding or honing machine, in combination, a reciprocating tool support, a plurality of spindles each iournalled' at one end on said support and adapted to carry on itsother end an expansible and contractible abrading tool, a tooladiusting meansfor each tool on said fluid pressure responsive means for expanding determined drop in the pressure applied to said second fluid pressure responsive means individual to that tool causes said second fluid pressure responsive means to produce a reversal of the operation of the valve means individual to ment, means for securing said tool in said spindle,

support including expansible and contractible a pressure fluid system-in said tool including a jet which is set relative to the desired diameter to be machined, and means responsive to changes in pressure in saidsystem for indicating when the diameter has been reached.

' JOHN E.

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