US2622375A - Grinding machine - Google Patents

Description

F. S. HAAs ETAL GRINDING MACHINE Dec. 23, 1952 Filed Dec. 6, 1949 10 Sheets-Sheet l INVENTORS 3 s n I E WWW lmWm n .T mwfi A R R r mm MW F W F W W Dec. 23, 1952 v F. s. HAAS Em. ,6 3

GRINDING MACHINE Filed Dec. 6, 1949 1o Sheets-Sheet 2 Fig.2

. I INVENTORS FEEDER/67f .SHflAS' BY W/NTHRUP TRIBLE A TTORNEYS Dec. 23, 1952 F. s. HAAs EIAL 2,622,375

GRINDING MACHINE Filed Dec. 6, 1949 lO'SheetS-Sheet 3 IN V EN TORS FEEDER/0K 5: H448 y w/lvrHwP T/F/BLE A] TT'ORNEYS Dec.- 23, 1952 F. s. HAAs ETAL 7 2,622,375

GRINDING MACHINE.

Filed Dec. 1949 10 Sheets-Sheet 4 F g, 5' INVENTORS FEEDER/0K6, H/J/Js B W/NTHROP T/F/BLE Dec. 23, 1952 F. s. HAAS ETAL GRINDING MACHINE 10 Sheets-Sheet 5 Filed Dec. 6, 194$ INVENTORS FREDERICK 8, H448 ATTORNEYS Dec. 23, 1952 F. S.-HAAS ETAL GRINDING MACHINE 16 Sheets-Sheet 6 Filed Dec. 6, 1949 Ullllll m was 58 R, wMm zn 3 W m HZ; HM F r RM Pu w W F. S. HAAS ETAL GRINDING MACHINE Dg'c. .23, 1952 Filed Dec. 6'; 1949 10 ShepW-Sheet 7 IITTORWEYS Dec. 23, 1952 F. s. HAAS ETAL 2,622,375

I GRINDING MACHINE Filed Dec. 6, 1949 1O Sheets-Sheet 8 INVENTORS FEEDER/0K 6, HflflS y W/NTHROP TH/BLE w. 950 M r $14M ATTORNEYS Dec.23, 1952 F. s. HAAS ETAL 2,622,375

GRINDING MACHINE Filed Dec. 6, 1949 10 Sheets-Sheet 9 JNVENTORS FREDERICK s, Hfl/IS By W/NTHROP Tfi/BLE imrazwwzfi A T TO/PNE Y8 Patented Dec. 23, 1952 UNITED STATES ATENT OFFICE GRINDING MACHINE ration of Ohio Application December a, 1949, Serial No. 131,414

8 Claims.

This invention relates to grinding machines and more particularly to an automatic machine, especially adaptable for grinding surfaces other than cylindrical surfaces such as flat or conical surfaces. Briefly summarized, this invention relates to the problem of grinding work surfaces which cannot be ground on the standard type of grinding machines, and are of such a nature that the work must be held by some form of chuck in order to properly present the surface to the grinding wheel. The present invention contemplates an improved automatic machine having two or more spindles, one of which may be at a grinding station while the other is at a loading station, the spindles being mounted in an indexible support movable from one station to the other, and a constantly rotating magnetic chuck located at-the grinding station for driving whichever spindle is at that station. The grinding wheel moves through an automatic grinding cycle including rapid traverse advance, feed, and rapid return. The operator reloads the work on the spindle at the loading station during a grinding cycle, and by pressing a preset button after a work piece is loaded, the support will index automatically at the end of the current grinding cycle, and after indexing the next grinding cycle will automatically start, otherwise the machine will stop at the end of the particular cycle.

Thus, one of the objects of this invention is to provide an improved automatic grinding machine having dual stations whereby the operator may load at one station while a work piece is being ground at a second station.

Another object of this invention isto provide an improved automatic cycle operating and con trol mechanism for a machine of the character described.

A further object of this invention is to provide an improved automatic mechanism for supporting and indexing work between a grinding station and a loading station and continuously driven means for rotating either spindle at the grinding station without the use of mechanical clutches. I

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction with the accompanying drawings forming a part thereof, and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

Referring to the drawings in which like reference numerals indicate like or similar parts,

Figure 1 is a view in elevation of one embodiment of this invention.

Figure 2 is :a section on the line 2-2 of Figure 1.

Figure 3 is a section on the line 33 of Figure 1.

Figure 4 is a plan View of the mechanism shown in Figure 1.

Figure 5 is a detail section on the line 5-5 of Figure 4.

Figure 6 is a section on the line 8- 5 of Figure 5.

Figure 7 is a vertical cross section on the line 'i1 of Figure 1.

Figure 8 is a vertical section as viewed along the line 8-4-1 of Figure 4, showing the actuating mechanism for the grinding wheel.

Figure 9 is a plan view partly in section as viewed on the line 99 of {Figure 1.

Figure 10 is a continuation of the plan view shown in Figure 9.

Figure 11 is a detail view showing the selector valve in its normal position.

Figure 12 is a detail view of a safety device as viewed on the line l2| 2 of Figure 1.

Figure 13 is a diagram of the hydraulic circuit of the. machine.

Figure 14 is an electrical diagram of the machine circuit.

Figure 15 is a detail view on the line l5l5of Figure '7.

Figure 16. is a detail sectional view on the line i6lfi of Figure 15.

Referringto the drawings, and more particularly to Figures 1, 4, and 8., there is shown the general structure of the machine, the work holding mechanism being shown more particularly in Figuresl and 4, and the grinding wheel supporting mechanism being shown in Figure 8. The grinding wheel head and actuating mechanism of Figure 8 is the same as that shown in co-pending application, Serial No. 734,080, filed March 12, 1947, and therefore the particular construction of this mechanism constitutes no part of the present invention. This mechanism, however, is adapted to move the grinding wheel through an automatic grinding cycle comprising a rapid traverse advance movement, a feeding or grindin movement and a rapid return movement.

The reference numeral it indicates apart of the bed or base structure of the machine, and the reference numeral ll indicates, in general,

the wheel head structure which is pivoted at l2, Figure 8, for swinging movement of the grindin wheel through an are indicated by the line [3. The grinding wheel indicated at M is suitably mounted for rotation on a shaft 25 which is journaled in the head ii. The head H is rotated counterclockwise at a rapid traverse rate by admitting oil through a pipe IE to a chamber I! which causes separation between the head II and a piston I8. A shoulder IS on the piston it limits the extent of the rapid traverse movement by engagement with the cylinder head 28. It will thus be noted that the parts in Figure 8 are shown in the position they assume at the end of the rapid traverse movement, or in other words at the beginning of the feed movement.

The feeding movement is effected by a piston 2 I which rotates a bell crank 22 acting on the end of the piston i8, thereby continuing the counterclockwise movement of the head H. The piston 2! is moved by admitting fluid pressure through the channel 23. This movement will continue until an adjustable stop 24 on the moving head I i engages a fixed stop 25 carried by the bed lil.

As the grinding wheel advances through its feeding stroke, it grinds the work piece, indicated generally by the reference numeral 26 in Figure 4, which is mounted on the end of a work receiving spindle 2'1 located at a grinding station, while a second work receiving spindle 28 is located at a loading station for receiving an unground work piece indicated by the reference numeral 29.

The spindles 27 and 28 are journaled in a rotatable drum 35 shown in Figures '7 and 9, which is enclosed in a housing 36. The housing is mounted for angular adjustment and as shown in Figures 1 and 4, the base of the housing 36 is supported on and pivotally connected by a pivot pin 3 l Figures 3 and 4, to a slide 32 which is guided on the bed for movement toward and from the grinding wheel. T bolts 33 movable in a T slot 34 formed in the slide 32 and passing through the base of the housing 38 serves to clamp the housing and contained spindles in proper angular relation to the axis of the grinding wheel. As shown, the axes of the spindles are perpendicular to the axis of the grinding wheel, and this makes it possible to grind flat surfaces on the end of the work pieces, such as 26, but the housing may be angular-1y adjusted about the pivot 31 for grinding conical surfaces on the work.

The drum 35, in which the spindles are mounted, is rotatably supported at opposite ends in the housing 36 by two sets of rollers, one set of which is shown in Figure 3. There are three equally spaced rollers 35, 3?, and 38 which are journaled in roller blocks 39 that are attached to the housing in such a manner that one end of the block is pivoted as at 46, and the other end of the block is acted on by an adjusting screw 4| threaded in the housing 33 and secured by a clamping nut 42 so that the block may be pivoted toward the center of the drum to preload the rollers and properly position the axis of the drum.

The drum 35- is adapted to be rotated 180 degrees back and forth to interchange the position of the spindles and to this end the periphery of the drum has a series of gear teeth 42, as shown in Figures 7 and 9, cut in its periphery to an angular extent slightly greater than 180 degrees, and these gear teeth mesh with a gear 43 which is fixed to a shaft 44 rotatably mounted in the base of the housing 30. This shaft also has fixed to it a pinion 45 which meshes with in its periphery with a stop pin 49 which is alternately engageable with the ends of stop bolts 49 which are threaded in the housing and are adjustable from the exterior thereof.

As a Work spindle is indexed into the grinding station, the end of the spindle opposite to the work receiving end is automatically positioned in line with a magnetic clutch mechanism for rotating the spindle and work for the grinding operation. This mechanism is shown more particularly in Figure 10, from which it will be noted that an armature plate 50 hasa central stud 5| formed on one side which is slidably mounted in a bore 52 formed in the end of a Work spindle, such as the spindle 21. A bolt 53 is threaded in the end of the spindle, and a spring 54 is interposed between the head of the bolt and a shoulder 55 formed at the end of a central bore 56 drilled in the stud portion 5 I. The spring tends to hold the armature plate 50 retracted from a magnetic clutch 51. This insures that the armature plates will not interfere with the magnetic chuck plate during indexing of the drum.

The armature plate engages driving pins 58 whichproject from the end of the spindle and are slidably mounted in bushings 59 carried by the armature plate. This allows the plate 50 to slide relative to the pins while still maintaining a driving connection with the spindle.

The magnetic clutch 51 has a series of magnetizing coils 60 mounted therein which terminate in two binding posts 6! mounted on the periphery of the member 5?, and these are electrically connected by wires 62 to armature rings- 63 and which are mounted in insulated relation on the periphery of a disc 64. This disc is keyed at 65 to the end of a shaft 65 which is mounted on anti-friction bearings 61 in an uprising support i553.v The end of the shaft 66 is provided with a drive pulley '69 which is suitably connected by V-belts 69 to the drive pulley 10, Figure 4, of an electrical motor H mounted on the plate 32. The motor H is continuously driven Which means that the magnetic clutch member 51 is continuously rotating, and at suitable times, to be explained hereafter, the clutch is magnetized to eifect rotation of the particular spindle which has been moved into alignment therewith at the grinding station.

The specific construction of the spindles is shown in Figure 9, from which it will be noted that the spindle 2?, for example, is rotatably journaled in the drum by means of spaced bearings i2 and i3. These bearings are of the rocker shoe type as shown in Figure '7. The spindle is held against axial movement in the drum by means of a collar '54 which engages a shoulder 15 formed on the spindle. A nut 76 which is threaded on the spindle and acts through the sleeve 'i'i, abutting the plate 18 mounted against the fixed part 13 of the drum, to pull the shoulder 15 axially against the member 7-! and thereby axially position the spindle as well as holding it against axial movement.

The work end of the spindle has a face plate 8Il=secured to: the spindle asby bolts6l, and this plate'has a central axially projecting stud82. Thisstud is threaded at-83 to receive a pair of lock nutsiM. A pair of telescoping chuck members85- and 86 are slidably mounted on the-stud and from theview of these parts shown in the lowerp-art of Figure 9 in connection with spindle 28, it will benoted that the members '85 and-86 aresplit to forminterlockingfingers 8i which are integral with the member35, and fingers v88 which. are. integral with the member 86. The member 35 is provided with a tapered seat- 89, whilethe member'Bfi is in abutting relation with the locknuts .84 whereby when the member 55 is pushed by a. series of pins. 55 towardthe member. 86, thefingers. are expanded outwardlyinto engagement with a bore SI. of the work piece25.

There are three equally-spaced pins. 90 around the stud Bias shown in-Figure 3. When the pressure is taken off of the pins, the fingers collapse sufficiently to permitremoval of the work piece, and when a new work piece is placed in position it is accuratelypositioned axially by means of another series of pins 92 projecting from the face plate 83. In addition, a driving pin 93 mounted in the plate83 hasa reduced end. 94 which" engages a hole 95 in the work piece toeffect rotation thereof upon rotation of the spindle. Both spindles are of thesame construction.

The chuck actuating pins '55 abut theend of a piston 95 which is slidably mounted in a cylinder 9'5 formed'in thefinterior of the spindle. The rear end as of'the piston communicates with an axial bore. es formed in the spindle through which hydraulic pressure is admitted to force the piston 95 axially. to the right as viewed in Figure 9 to effect expansion of the chuck. Upon withdrawal of the hydraulic pressure, a spring I55 encircling the reduced end of the piston effects retraction of the piston to permit contraction of the chuck.

The bore 99 extends to the rear end of the spindle 21 as shown in Figure and is closed by a plug I55. However, a cross bore I 52 is drilled in the tapered endv I93 of the spindle and in communication with a radial bore I 34 formed in a sleeve I35 which is held in position on the taper by a lock nut I35 threaded on the end of the spindle. The bore ifidterminates in an annular groove I91 which is in constant communication with a bore 838 whichterminates in a threaded portion Itil'to which the pressure supply pipe Ii is connected. The bore I38 is formed in a sleeve. I II which is held'against a shoulder IE2 of the member I55 by suitable springs I I3 to maintain the parts in position and to prevent leakage. In this connection, attention is invited to thefact that the spindle and sleeve I35 rotates together by means of the key connection H4 and that the member III is held against rotation by the pipe connection H5.

The pipe H5, as wellasapipe H5 which supplies fiuid pressure to the chuck on spindle 28, which is of the same construction as spindle-21, are connected to the center of the drum by being threaded in the ends of bores lit and Ill, Figure 9, formed in a plug H8 which is integral with the drum. It is to be rememberedthat the drum rotates through anangle of 180 degrees to alternately position the spindles in loading position and grinding position, and therefore these hydraulic connectionsmust be maintained for either position of the drum, but the spindles also rotate independently of the drum.

The bores II 6' and I IT, as. shown .in FigureuQ,

are connected by pipes H9 and I to bores I2I and I22 formed in a centrally located member I23 with respect to the drum and rotatable therewith, and this member has a portion- I24 which-projects beyond the end face of the drum. The passages I2I and I22 are connected by cross bores I24 and I25 respectively to annular grooves I26 and I2! formed in the periphery of. the por tion I24. 'Iheportion I24 has a shoulder I28 formed thereon against which abuts a fixed member I29 in which is formed interdrilled passages, one of which is shown at I which is in constant communication with the annular groove I2I. These interdrilled passages terminate ina cap member. I3I .secured to the end of the member I29and also to an upstanding fixed bracket I32 shown in Figure 1, which bracket is fixedto the. base of the housing 33. Since the bracket is fixed, the cap I3I and themember I29 are held against. rotation during rotation of the drum, but it will be noted that the construc tion is such as to maintain the hydraulic connections regardlessof rotation of the drum. The interdrilled passage I33 and the interdrilled passage I33 communicating with the annular groove I26, shown in Figure 13, terminate in pipes I33 and 135 respectively which terminate in the chuck selector valve, indicated generally by the reference numeral I36 in Figures 4, 5, and 6. The pipe I34 terminates in the annular groove I31 in Valve sleeve I33 and the pipe I35 terminates in the annular groove I39 in valve sleeve I40 as shown in Figures 5 and 13.

The valve sleeve 138 has a valve plunger MI, and the sleeve I39 has a valve plunger I42, which plungers are slidably mounted in their respective sleeves, and as shown in Figure. 11, held in normally retracted positions by springs I33. A rock lever I44 centrally pivoted at M5 abuts the ends of the respective plungers and is held in balance against the'wall M5 by the springs M3. In this position the valves connect a source of pressure to the respective work chucks, thereby holding the chucks in work engaging position.

Referring to Figure 13, fluid pressure is supplied to the valves by pump Ml which has an intake I45 'for withdrawing fluid from a suitably-located reservoir I49 in the machine, and a delivery line I553. This line has a branch connection to a relief valve I5I for returning excess fluid to reservoir. "Ihe line I53 is connected through a pressure'reducing valve I52 to a supply line I53 leading to the valves MI and M2 and terminating in the pressure grooves I54 and I55. Thus, when'both valve plungers are in the retracted position fluid pressure is connected to both chucks.

A common actuating mechanism is provided for moving the valve plungers, but only one plunger is moved at a time by the mechanism, the plunger being moved depending upon the position of the drum. The common actuating mechanism includes a manually operated lever I56 attached to the end of a shaft I51, Figure 6, which is journal'ed in the valve housing I36 and the inner end of the shaft has a crank arm I58 which carries the pivot I45 upon which the rock lever I49 is mounted. Thus, when the lever I56 is moved to the right, the crank arm 158 moves clockwise as viewed in Figure 5 and thereby exerts pressure on the rock lever I49 to shift the plungers.

It will be noted that the drum 35 has a first depression I59 formed in the periphery thereof which is opposite the plunger MI in one position of the drum and a second depression I60 on the opposite side of the drum which upon rotation of the drum through an angle of 180 degrees is positioned opposite the plunger I42 as shown in dotted lines in Figure 5. Thus, upon movement of the common actuator I56 one plunger is held or blocked against movement by the periphery of the drum and the other plunger is free to move into the depression opposite the respective plunger whereby the rock lever is pivoted about the end of one plunger and caused to move by the crank lever to shift the other plunger. It will thus be seen that a common actuator is provided for shifting either plunger and that the plunger to be shifted is automatically determined by the position of the drum, and furthermore the position of the drum determines which work chuck is at the work loading station so that only the chuck at the work loading station is released, and this automatically insures that the chuck at the grinding station cannot be accidentally released.

Provision is made for slight lateral adjustmen of the drum to slightly change the pivot point of the pivot pin SI, shown in Figure 3, to assist in locating the work with respect to the grinding wheel and to insure that the flat face being ground on the end of the work is normally to the axis of the work and thereby to the axis of the work supporting chuck. This is accomplished by mounting a pivot block [6| in a T slot I52 formed in the base of the housing 30 and mounting the pivot block on the end of the pivot pin 3 I. An adjusting screw I63 is anchored at I64 to the housin 30 and threaded at I85 in the block. Thus, upon rotation of the screw the block I58 does not move but the entire housing will be moved laterally. This slightly changes the pivot point about which the housing will be swiveled upon adjustment thereof. After adjustment the pivot pin is clamped by a tapered ended clamp member I58, which is secured in position by a set screw I81.

The machine is operated and controlled in the following manner, reference being had to the hydraulic diagram of Figure 13 and the electrical diagram of Figure 14. For purposes of continuity of this explanation, an unground work piece 29 is placed on the spindle 28 and in order to make this possible the lever I56, as shown in Figure 13, is moved to the right which permits the fluid pressure in the spindle 28 to be exhausted to reservoir through the line I34 and line I68, thus permitting retraction of the piston 96 so as to release the chuck and permit the work piece to be mounted on the end thereof and against the locating pins 92. Upon release of the lever I56, the valve plunger MI is retracted by its spring, thereby connecting the pressure supply line I53 to line I34 whereby the work becomes clamped on the chuck. The next step is to index the drum to move the unground work piece to grinding position which is effected by means of the electrical control circuit shown in Figure 14.

In the electrical control circuit there is shown a transformer I69 which is adapted to be connected through suitable switch means to a source of electrical power. The secondary of this transformer has two lines which may be diiferentiated by designating the line I10 as the power supply line and the line I1I as the power return line. The power supply line I10 has a cycle stop switch I12 therein for stopping the entire machine cycle at will. This switch is connected by a line I13 to a cycle start button I14. It will be noted that the line I13 has a branch connection to an indicium I15 in the form of a black square. This square is repeated at various points in the electrical diagram to indicate the power supply line and thus eliminate the necessity of running connecting lines across the drawing, thereby making the diagram clearer. Therefore, wherever a black square appears on the diagram, it indicates the power supply line. Similarly, an indicium in the form of a black triangle I16 is attached to the end of the power return line HI and wherever the triangle I16 reappears in the electrical diagram it is synonymous with and indicates the power return line and thus avoids the necessity of extra lines on the electrical diagram.

The operator starts the automatic cycle of the machine beginning with the indexing of the drum by pressing the start button I14 which connects the power supply line to line I11, which is connected in parallel through lines I18 and I19to switches CBS-2 and CR4-3 of index control relays CR3 and CR4 respectively, which relays are respectively energized in accordance with the position of limit switches LS! and LS2 which, in turn, is determined by the position of the drum.

Thus, the relay CR4 is shown energized by limit switch LS2 and relay CR3 is deenergized by limit switch LSI. Accordingly, the switch CR3-2 is closed at this time while the switch CR4-3 is open. A circuit is thus established through switch CBS-2 from line I18 to line I89, which line continues to the normally closed switch TR2-I of timer relay TRZ. The circuit continues through line I8I, closed switch I82 of relay BW-I which is serially connected with closed switch I83 of a second relay BW-Z, and line I84 to cycle control relay CRI. This relay becomes energized, thereby closing its switch CRI-Z to set up a latching circuit from the power line I 15 to line I so that the relay CRI is now latched in independent of switches CR3-2, CR4-3, and the start button, which is released. Power is thus connected to the circuit. The line I80 has a branch line I85 to closed contacts I85 of limit switch LS-I which is electrically connected through line I81, closed switch CRIS-I, line I88 to control relay CR5, causing energization thereof. This relay closes its switch CRE-I, completing a circuit from the power supply line I15 to indexing solenoid I89. Thus, the cycle control relay CRI starts the cycle by shifting the indexing valve. Relay CR5 also closes its switch CR5-2 to set up a latch circuit from line I 88 through line 282, closed switch CR5-2, line 283, line I81, closed switch CRIS-I and line I88.

Referring to the hydraulic diagram of Figure 13, it will be noted that the solenoid I89 is connected by a rock lever I99, centrally pivoted at I9I to the reversing valve plunger I92 which controls reciprocation of the rack piston 41. By energizing the solenoid I 89, the valve plunger I92 is shifted to the right, thereby connecting the pressure port I93 which is directly supplied by the pump I41 through line I 94 to port I95 whereby fiuid pressure will flow through line I96 to the right hand end of cylinder 48, thereby shifting the piston 41 to th left and, through the interconnected gearing, causing counterclockwise indexing of the drum. As soon as the drum starts rotation, the limit switch LS2, as shown in Figures '7 and 15, will be actuated by riding out of the depression I91 formed in the periphery of the drum and thereby open'the circuit to the relay CR4 as seen in Figure 14 and simultaneously close its switch contacts I98.

The drum continues to rotate for substantially 180 degrees during which time both relays CR3 and CR4 are released. A second depression H99 formed in the periphery of the drum and spaced 180degrees from the first depression I97 permits limit switch LSI to operate, opening its contacts I86 and closing its switch contact 239, completing a circuit from the power supply line H to indexcontrol relay CR3 through line 20!. Relay CR3, in turn, closes its switch CR3-4 and establishes a circuit beginning from the line we through line 202,- closed switch CR5-2 of relay CR5, line203, line 204,- closed switch CR3-tof relay CR3, line 285 to line-Ziiiiwhich is connected to the'timer relay TRI. This timer relay is set for time closing, thereby providing a slight delay to insure that the hydraulic piston 41 has moved the-drum against a positivestop as shown in Figure 2, and then the relay closes its switch TRi-i and completes a circuit from line-Hitl-to operate rapid traverse control relay CR1. Operation of this relay closes its switch CRJ-I and completes a circuit from the power supply line 1 15 through line 291 to rapid traverse solenoid 208.

This solenoid, as shown in Figure 13, is connected to the rapid traverse control valveplunger 209, thereby shifting the plunger to the left. This valve is already shown in its shifted-position due to the fact that the-wheel head is shown,

in the position it assumes at the end of the rapid traverse movement or, in other words, at the beginning of the feed movement. Thus, when the valve 209is shifted to this position, it connects thepressure port 2 I ll, which is alsosupplied from the pump line I94 to port 2! l whereby fluidpressure flows through line le-to chamber H as previously described, moving the wheel head at a rapid traverse rate tothe position'shown in Figure 8.

When the wheel head reaches the position shown in Figure .8, a dog 2 I 3 attached to the wheel head operatesthelimit switch LS3 and thereby movesits contactor 214 to close switch contacts 2 l 5 .and complete a circuit from the power supply line I15 .through line .2l6 to operate feed control relay CR8; Thisrelay closes its switch CRB-I and completes a circuit from the power supply line Il5through line 2 H to the feed solenoid 2I8. The solenoid MS, as shownin Figure 13, is. connected to the feed valve plunger 2 l 9 which is normally held by a spring 220 .in the position shown. This valve has a pressure port 22I, which is also connected to the pump line I94, and when. the

plunger is shifted to the .left, this port is connected to:port'222 whereby fluid flows through line 223 to the feed cylinder 224. moves to the right, asviewed inv Figure 13, and through the bell crank 226 moves the entire wheel head assembly, shown in Figure 8, in a counterclockwisedi'rection. to feed the grinding wheel intothe work to effect thegrinding operation- The work spindle and the work have been set in rotation beforeithis by therapid traverse con-- trol relay CR7 which closedits other switch CRT-2 and, completingv a-circuit fromline I30 through line 211, closed switch CR'lJ-z-and line 228 to the rectifier 229 which supplies direct current to the magnetic clutch 51. As shown in Figure 10, thisconnects the drive pulley 69 to'the drive plate 50 on the end of the chuck'spindle;

The grinding operation continues according'to This the time setting of the timer relay 'TR2. relay was energized simultaneously withfeed The piston 225 relay CR8 by the closing of limit switch LS3,- the relay being connected by a branch line 230 to line 2| 6. This relay is set for a timed opening which is of just sufiicient time to permit the stop 24 on the wheel head to engage the positive-stop 25 and still allow a slight tarry before the wheel head is withdrawn to allow the grinding wheelto spark out. The timer relay then opens its switch TRZ-l thereby breaking theholding circuit to cycle control relay CRI During the grinding operation just described the operator is loading another workpiecein the chuck located at the loading station. Two alternatives now happen. One is that when the timer relay TRZ operates, it can causeretraction of the grinding wheel and the machine will stop. The other is that, if the operator completes the loading operation before the work piece at the grinding station is completed, he may press the starting button I M and set up a condition in the circuit whereby themachine will continue into the next cycle without stopping.

In the first alternative the timer relay will break the holding circuit to control relay CR1, and its switch URI-2 will "disconnect the source of power from line I80, deenergizing the solenoid relays CR5, CR7, CR8, so that the control valves will spring return and cause the grinding wheel headto retract to a-stop position; and'rotation of the workwill stop because of deenergization 'of the magnetic clutch 5'! by opening of switch CR'i-Z.

In the other alternative, the operator will press the button IM'after loading the work piece and before the grinding cycle is completed. By so doing he completes a circuit through the-button to line 23!, closed switch CR82 of feedrelay CR8;

and line 232 to cycle preset control relayCRZ. Thi relay will close its switches CR2-1 and CRZ-Z. The closing of switch CR2-2 will set up alatching circuit from the supply line I15 through line 236, switch CR22,- line 231, branch line 242,-

The return movement of the wheelhead'starts with the release of solenoid 2B8, causing the rapid traverse 209 to shift to the right byspring 2st, thereby connecting line it from the rapid traverse cylinder I! through port. 2!! to an exhaust port 23s whereby the fluid in cylinder 11 is free to return to reservoir through line 240 and low pressure relief valve 2 3! As the wheel head returns, it operates limit switch LS3 which thereby opens the circuit to line 2E6 to release-and simultane ouslyopen the circuit .to relay'TR2' which closes TR2-'l. This deenergizes the solenoid MB-whereby the feed valve plunger 2E9 is returnedto the position shown in Figure '13 to connect the feed cylinder 224 to reservoir.

Summarizing the cycle so far; the timer relay 'Il'tZ which determines the length of timeof. the grinding operation opens :the holding .circuit to traverse return of the Wheel head.

During the grinding operation, the operator latched in the cycle preset relay CR2 by pressing the starting button, thereby setting up a potential circuit through an open switch of the feed control relay CR8 for reconnecting power to the line I89.

During the rapid traverse return, the wheel head operates the limit switch LS3 to release the feed control relay CR8 so that its open switch now closes to complete the potential circuit to line I88. At the sam time the limit switch LS3 opens the circuit to the timer relay TR2 whereby its switch TR2-I returns to its normally closed position connecting power from line I88 to operate relay CRI which again establishes a latching circuit through closure of its switch CRI-2 to maintain a power connection to line I89.

Due to the fact that relay CR5 was released when power was disconnected from line I80 it closed its switch CR5-3 whereby upon reconnection of power to line I80 a circuit is set up from line I88 through line I85, closed contacts I98 of limit switch LS2, line 245, line 246, line 241, closed switch CR5-3, line 248 to control relay CR6. A relay CR6 controls indexing of the drum in a direction opposite to the direction controlled by relay CR5.

The relay CR6 opens its switch CRS-I, opening the circuit between line I81 and line I88 which leads to relay CR5; and closes its switches CR6-2 and CR6-3. The switch CR6-2 latches in the relay CR6 by completing a circuit from line I88 through line 249, closed switch CR62, line 258, line 245, line 246, line 241, and closed switch CR5-3 and line 248. This short circuits out the limit switch LS2.

The switch CR6-3 completes a circuit from the power line I through line I, flow switch ORG-3, and line 252 to solenoid 253.

Referring to Figure 13, the solenoid 253 shifts the indexing valve plunger I92 into the position in which it is shown in the drawing, thereby connecting the pressure port I93 to port 254 and line 255 to the left end of the piston 41 which thereby moves to the right, causing clockwise rotation of the drum 35. The initial rotation of the drum operative limit switch LS-I, thereby opening its contacts 208 and breaking the circuit to relay CR3, and final rotation of the drum operates limit switch LS-2, opening its contacts I98 and closing its contacts 256 to complete a circuit from line I15 to relay CR4. Operation of relay CR4 closes its switch CR4-4, which completes the circuit from the line I80 through line 249, closed switch CR2-2, line 258, line 251, closed switch CR4-4, line 258, and line 206 to timer relay TRI. This relay closes its switch TRI-I and completes a circuit to rapid traverse control relay CR1 which closes its switch CR1-I and effects operation of solenoid 288 to start the rapid traverse movement of the next cycle.

The grinding cycle continues in the same manner and at the end of the grinding cycle the line I88 will again become deenergized, dropping out the relay CR6 and closing switch CRIi-I. On the next indexing movement, switch CR34 of index controlled relay CR3 will be closed and the switch CR4-4 of index control relay CR4 will be open, whereby the relay CR5 will operate to effect the next indexing movement.

For protection during the indexing operation a safety device is provided to protect the machine against oversize work pieces as well as detecting whether the work piece is properly seated in the chuck. This device comprises a pair of rods 258 and 259 shown inFigure 1 opposite the work loading station, these rods being supported in the ends of lever arms 268 and 261 respectively as shown in Figure 12, the arms being supported for rotation about a common center 262. The-rods are insulated from their respective lever arms, and the rod 258 has a wire 262 connected thereto, and the rod 259 has a wire 263 connected thereto. A spring 264 urges the lever arms toward one another and against stop pins 265 which positions the lever arms at a predetermined angle. The levers are free to swing away from the stop pins in case of engagement of the work piece with either rod. The rods are so positioned as to provide the necessary clearance desired, but should the work piece project from the chuck beyond the predetermined amount when the drum is rotated, the work piece will engage either one rod or the other, depending upon the direction of rotation of the drum.

In the electrical diagram in Figure 14, the rod in lever arm 269 is electrically connected by the wire 262 to the secondary 266 of transformer BW-I, while the rod in the end of arm 26I is connected by the Wire 263 to the secondary 261 of the transformer BW-2. It will be noted that both of these secondaries are connected to ground indicated by the reference numeral 268 whereby should the rod in either lever arm engage the work piece the other end of the secondary will be grounded through the machine, thereby. completing a closed circuit through the secondary. It will be noted that each of these transformers has a primary coil, the ends of which are connected to the power supply line I15 and the power return line I16. This causes a flow of flux through the armature leg upon which the secondary coil is wound.

So long as the secondary coil circuit is open there will be a free flow of flux through its armature, but when both ends of the secondary coil,

are grounded, an inductive current is created in the secondary coil which opposes flow of flux through the secondary armature, thereby increasing the flow of flux through the two legs 289 and 219 which thereby creates a magnetic circuit through the switch arm 21I to attract and operate the switch, The operation of either switch arm will break the circuit to the control relay CRI and in the case of switch arm 21I will complete a circuit from the power supply line I15 through line 212, closed contacts 213 and line 214 to switch CR4-2.

If this switch is closed, a circuit will be completed to line I88 and index control relay CR5, causing operation of this relay. If the other switch arm 215 is operated, it will complete a circuit from the power source in like manner through line 216 to switch CR3-3, and if this switch is closed the circuit will be completed through line 211 to index control relay CR6. It will be obvious that at the time of indexing either relay CR5 or CR6 will be energized to cause the indexing movement. Therefore, the connections are such that if an interference rod is grounded, it will break the circuit to the energized index relay, thereby stopping the indexing movement in that direction and energizing the other index control relay to reverse the direction of indexing and cause the work to return to the loading station so that the operator can examine the work and make the necessary adjustments.

For manual control of the indexing operations a cycle delay switch 218 is provided which when operated causes its lever arm 219 to break the circuit to line 238 and cause lever arm 288 to close-a circuit from the power'supply line I15 through closed contacts 28! of limit switch LS3 to line 282. This line is connectible by the manual push button switch 283 to line 286 which leads to relay CR5 through switch CRfi-I, while a second manually operated push button switch 285 serves to connect the line 282 to line 286 and thereby to index relay CR6 through switch GEE-3. Thus, either one of these relays may be manually controlled to effect an indexing of the work drum. To be sure that the grinding wheel is retracted, in either case, the switch 283 has a second contactor 281 in series with another contactor 288 of push button 285 whereby operation of either of these push buttons will break the circuit of line 206 to the timer relay TRI, which through its switch TRl-l will break the circuit to the rapid traverse control relay CRT.

. It should now be clear that an improved machine has been provided for automatically grinding fiat faces on the ends of work pieces and that the manner of operation of the machine is fully automatic, the operator loading the work in the chuck that is located at the loading station by operating the lever I56 to release the chuck while the work is being changed. The operator then presses the start button and when the grinding operation on the other Work piece is finished, the work drum will be automatically indexed to reverse the position of the two work pieces. The electrical circuit serves to coordinate the automatic cycle of the grinding machine with the automatic cycle of the indexing mechanism.

What is claimed is:

1. In a grinding machine having a support, an indexible spindle carrier mounted on the support, a pair of Work spindles journaled in the carrier parallel to the axis of carrier rotation, means to reversibly index the carrier 180 degrees to position the spindles alternately at a grinding station and a work loading station, a grinding wheel mounted on the support at the grinding station for grinding work supported in the end of that spindle located at said station, a continuously driven rotator mounted on the support adjacent the other end of said last-named spindle, a magnetic clutch carried by the rotator for automatic coupling with the respective spindles at the grindingstation, power operable means for feeding the grinding wheel, additional power means for energizing said clutch, a control circuit operatively connected to said clutch and power operable means, and means operable by the carrier upon completion of an indexing movement to energize said circuit to effect a grinding operation. 2. In a grinding machine having a support, an

indexible spindle carrier mounted on the support,

a pair of work spindles journaled in the carrier parallel to the axis of carrier rotation, means to reversibly index the carrier 189 degrees to position the spindles alternately at a grinding station and a work loading station, a grinding wheel mounted on the support at the grinding station for grin-ding work supported in the end of that spindle locatedat said station, a continuously driven rotator mounted on the support adjacent the other end of said last-named spindle, a magnetic clutch carried by the rotator for automatic coupling with the respective spindles at the grinding station, power operable means for feeding the grinding wheel, additional power means for energizing said clutch, a control circuit operatively connected to said clutch and power operable means, means operable by the 14 carrier upon completion of an indexing move+ ment to energize said circuit to effect a grinding operation, and means in said circuit responsive to predetermined movement of the grinding wheel to deenergize said circuit and stop the grinding operation.

3. In a grinding machine having a support, an indexible work spindle carrier reversibly, oscil-. latably mounted on the support for movement through half a revolution to alternately position work spindles carried thereby at a loading station or a grinding station, each of said spindles having a work holding chuck, fluid operable means for releasing said chucks including individual control valves, a common actuator for moving said valves mounted on said support ad= jacent the carrier, and locking means selectively positioned by the carrier in accordance with the rotatable position thereof to alternately render said valves non-responsive to movement of said actuator.

4. In a grinding machine having a support, a housing mounted on the support, anindexable spindle carrier, means for supporting the carrier within the housing for rotation, work spindles journaled in the carrier, a hydraulic piston mounted in the support and operatively connected to the carrier for effecting rotation thereof through one-half a revolution to alternately position the work spindles at a loading station and a grinding station respectively, stops carried by the housing for locating the carrier in either position, and means to maintain pressure in said cylinder to hold the carrier against the respective stops during a grindin operation.

5. In a grinding machine having a support, an indexible carrier, means rotatably supporting the carrier on said support, a plurality of work spindles journaled in the carrier, one end of said spindles having means for receiving and securing a work piece, the other end of said spindles having an armature plate secured thereto, means on said support rotatably mounting a magnetic clutch plate, power operable means on the support for continuously rotating said clutch plate, power operable means for indexing the carrier to position a spindle in axial alignment with said rotating clutch plate, and means to successively energize said clutch after each indexing of the carrier to eiTect magnetic coupling thereof with the armature plate on the spindle positioned in alignment therewith.

6. A grinding machine having a support, an indexible spindle carrier, a carrier housing mounted on the support having means for rotatably supporting the carrier, work spindles Journaled in the carrier, each spindle having fluid operable means for operating a work receiving chuck mounted in one end of the spindle including a fluid operable piston axially slidable Within the spindle, a hydraulic collector sleeve connection to the other end of the spindle including a non-rotatable sleeve fixed to the carrier, hydraulic channels extending through the center of the carrier with one end connected to the respective sleeves, a hydraulic collector sleeve mounted on the carrier having hydraulic connections to said channel, a control valve means mounted on the housing and hydraulic connections from the valve means to said last-named collector sleeve whereby the chucks may be remotely controlled from said valve.

'7. A grinding machine having a support, an indexible spindle carrier, a carrier housing mounted on the support having means for rotatably supporting the carrier, work spindles journaled in the carrier, each spindle having fluid operable means for operating a work receivin chuck mounted in one end of the spindle including a fluid operable piston axially slidable within the spindle, a hydraulic collector sleeve connection to the other end of the spindle including a non-rotatable sleeve fixed to the carrier, hydraulic channels extending through the center of the carrier with one end connected to the respective sleeves, a hydraulic collector sleeve mounted on the carrier having hydraulic connections to said channel, a pair of control valves mounted on the housing having a source of hydraulic pressure connected thereto, a control lever for simultaneously operating said valves to release the pressure in said channels, and blocking means selectively positioned by the carrier in accordance with the rotatable position thereof for inhibiting movement of one or the other of said valves upon operation of said lever.

8. A grinding machine having a spindle carrier with work spindles journaled therein, means to index the carrier to successively position the spindles at a, grinding station, a grinding wheel movably mounted on the support opposite one 16 end of the work spindle at the grinding station, a spindle rotator mounted on the support opposite the other end of the spindle located at the grinding station, means to continuously actuate said rotator, power operable means for feeding said grinding Wheel, a magnetic clutch carried by the rotator for coupling the rotator to the spindle, and means to simultaneously energize said clutch and said power operable means.

FREDERICK S. HAAS.

WINTHROP TRIBLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,588,739 Johnson June 15, 1926 1,794,440 Bryant Mar. 3, 1931 1,888,710 Arter et a1. Nov. 22, 1932 2,003,269 Arter et a1 May 28, 1935 2,109,600 Vanderbeek Mar. 1, 1938 2,369,114 Andersen Feb. 13, 1945 2,436,561 Flygare et a1. Feb. 24, 1943 2,475,091 Hackman -1 July 5, 1949

Images