US3079740A - Method of positioning grinding disks - Google Patents

Description

March 5, 1963 H. J. FALLON METHOD OF POSITIONING GRINDING DISKS 2 Sheets-Sheet 1 Filed NOV. 24, 1959 I VEN TOR.

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pal/4W far/er if/aways March 5, 1963 Filed Nov; 24, 1959 H. .1. FALLON 3,079,740

METHOD OF POSITIONING GRINDING DISKS 2 Sheets-Sheet 2 free more

Filed Nov. 24, 1959, Ser. No. 855,051 4 Claims. (Ci. 51-281) This invention is in the field of grinding and is concerned with a method of sizing for accurately positioning a grinding wheel in a disk grinder or the like.

A primary object of the invention is a method of sizing which does not require physical contact with the faces of the grinding disk in a disk grinder.

Another object is a gauging method which uses an air jet to sense the position of the face of the disk.

Another object is the use of a nozzle which is movably mounted in a double disk grinder so that the disks may be moved in somewhat preparatory to a dressing operation.

Another object is a gauging method for double disk grinders which is particularly beneficial for or with an automatic dresser.

Another object is a gauging method which senses the disk face in an accurate location.

Another object is a gauging or sizing method which may be used with a rotary, oscillating through feed, or any suitable feeding mechanism.

Other objects will appear from time to time in the ensuing specification and drawings in which:

FIGURE 1 is a schematic or diagrammatic layout of the invention;

FIGURE 2 is a perspective of a portion of the grinder;

FIGURE 3 is a side view, on an enlarged scale, of the air nozzles previously shown schematically; and

FIGURE 4 is a section along line 4-4 of FIGURE 3.

In FIGURE 1, the disks 1% of a double disk grinder have been shown opposite each other spaced apart a predetermined distance so that the workpieces may be passed between the disks to grind accurate parallel opposite surfaces by direct contact with the disk faces 2. The disks are mounted on shafts 1d and are rotated by any suitable drive. Nor is the make-up of the specific grinding disks important, other than that they may be suitable abrasive grinding wheels.

I show two air nozzles or jets 16 positioned between the grinding disks, back to back, with openings so that the air jets from tlr: nozzles will be directed in opposite directions. It will be noted in FIGURE 1 that the nozzles are opposite the faces of the disks and the air jets from the nozzles will strike or impinge against the faces 12 of the disks. The nozzles are mounted on a suitable support 18 and are supplied with air through suitable conduits or tubes 2i) from controllers 22. Air from the air source, such as a compressor or the like, not shown, is supplied to each of the controllers by suitable connections 24 and the air is monitored or controlled by the controller and in turn is passed through the tubes 2%"; to the nozzles 16. The controllers may be of the type presently sold by Moore Products Company of Philadephia, Pa., and, in detail, are not important to "this invention. Suiiice it to say that the controller basically senses the variations in a pressure signal and converts it to an electrical signal by operating switch contacts or the like. The controllers sense the pressure of the air passing through the system to the nozzles and in response to that pressure control the infeed of the grinding disks toward each other. It will be noted in FlGURE 1 that the grinding disks are constructed to be moved toward each other as the faces wear away during grinding, such movement being indicated by arrows. The controllers each send a signal to the disk'feeding mechanism, to be set forth. more in detail hereinafter, through suitabe leads 26. The controllers may be supplied with current through suitable leads 27 from an outside power source.

Workpieces are passed between the faces 12 of the grinding disks. As the disks break down or wear away, the faces will move farther and farther away from the jet outlets of the nozzles 16. This reduces the resistance to the outflow of air from the nozzles thereby causing the pressure of the air in the system to drop. The controllers can be set up so that in response to a predetermined low pressure, a signal will be sent through electric leads or otherwise, to the infeeding mechanism which will move either one or both disks toward each other. As the disk face approaches the nozzle opening, it will offer more resistance to the air flow. This will cause the air pressure in the system to increase. A controller may be set up so that at a predetermined high pressure the infeed will cease.

The grinding wheel infced mechanism may be set so that in response to a signal from the controller, it will automatically infeed a set amount. As soon as the air pressure in the system drops to a predetermined low, the controller will send a signal to the infeed mechanism causing it to infeed a predetermined amount. The infee-d of the wheel face will cause the air pressure in the system to rise, and if it rises above a desirable minimum or within a preset range, no further infeeding will be necessary. But if it is still below, the controller will again send a signal causing another infeed until the desirable spacing is obtained.

In FIGURE 2, one of the disks 1G is shown with its nozzle 16, it being understood that the showing in H6- URE 2 could be either disk of FIGURE 1. The disk is rotatably mounted in a quill 28 and is driven by a drive 30 which leads to an electric motor or the like, not shown.

The quill is constructed to be moved axially by cylinders 32 which traverse it in an axial direction rapidly back and forth between grinding and dressing positions. As shown in FIGURE 1, the wheels are in grinding position and are closely spaced. When the wheels have broken down sumciently so that dressing is required, the quills are moved outwardly a predetermined amount by the quill cylinders 32 and a dresser with oppositely disposed diamonds, not shown, is passed between them to dress off the face of each wheel. I prefer that the two quill cylinders lie in a horizontal plane which passes through the center of the disk and spindle 14 so that the reactive forces will be counter-balanced. The quill is supported by and is constructed to slide back and forth on suitable pads 34. Since the drive Sit is intended to be stationary, I connect it to the projecting end of the disk spindle by a spline connection 36.

Mounted above the quill and connected firmly to it by a key connection or the like is a spindle lug or bracket 33 which supports an air cylinder 40. The infeed mechanism 42 is suitably supported by the frame of the machine and includes a cross shaft 44 constructed to be rotated by an automatic ratchet or clutch mechanism and drive 46 or the like connected by leads 26 to the controller to'move a feed screw 43 through a suitable gear, pinion, and nut arrangement 59. Rotation of the cross shaft 44 causes the Worm gear or rack 48 to move to the left in FIGURE 2 thereby moving bracket 38, quill 28 and the diskltl axially toward the air nozzle 16. The feed screw 48 has a collar 52 which abuts a block 54- connected to the piston rod56 of the air cylinder 49. Thus, the air cylinder 4i? raises and lowers the block 5 3 to either position in between the bracket 38 and the collar 52 or to raise it above the collar 52 so that the quill cylinders 32 may move the quill and the grinding disk outwardly until the face of bracket 38 contacts the collar 52. I

During normal operation, air pressure is supplied to the quill cylinders 32 so that-they are thrusting outwardly or tend to pull the disks 16 outwardly away from grinding position and away from each other. This eliminates all backlash in the-infeed mechanism 42. When the disk. face-s have broken down-to a degree such that a dressing operation is desirable, first the'air pressurejis reversed in the quill cylinders so that the thrust is inwardly. This relieves the pressure between the various parts in the infeed mechanism and the air cylinder 40 can'ea'sily raise the block 52. Then the airpressurein the quill cylinders 32 is again reversed and since the block isup and out of the way' the quill will move outwardly until the face of the bracket 38 contacts the collar 52 on the feedmechanism. Then the automatic dresser, not shown, passes between the grinding disks across the disk faces to dress them. Then the air pressure is again reversedinthe quill cylinders to bring the quill and the grinding disks back to grinding position where they are more closely spaced and normal grinding starts again. 7

During normal operation, the air nozzles are quite close to the faces of the disks. For example, they might be at .005 inch. Since the quill cylinders are initiallyre versed to allow the block 54 to be raised, there is some inward movement of the disks which may-be on the order of 7 or 8 thousandths of an inch. To prevent the face of the disk from contact of the nozzle, I mount thenozzle so-that it will also move inwardly or in the same direction as the movement of the disk, as shown in detail in FIGURES 3 and 4. A suitablemounting bracket 58 on the frame of the grinder may have a nozzle 60 connected to it by a suitable cap 61 and mounting bracket 62 held by bolts 64 or otherwise. The second nozzle structure 6 6 may be mounted on the lower surface of mounting bracket 62 by a mounting bracket 68 and cap 70 c0nnected by bolts 72 or the like. It will be noted thatthe 'upper'part 73 of mounting bracket 68 is in a guideway 74 on the lower surface of the upper mountingbracket L62 andis constructed to be adjusted longitudinallyin any suitable rnannerand held, when in position, by abolt and slot connection indicated generally at 75.

i The nozzle structure, shown in detail in FIGURE -4, includes an air cylinder 76 having a piston rodl7 8 extending from it. End caps 80 and 82 are separated by a sleeve type spacer 84 and are connectedito it bybo lts 86. flhe end caps '80 and 82 carry spacing pins 88 which are adjustably positioned on each side of a stop plate 90.

the nozzle 16 may be tied into or related directly or V assumed at the beginning of a dressing operation.

The {outer ends of the pins 88 are-beveled and engage adjustable stop screws 92 which vary the position of the spacing pins 88. Stop plate 90 is against a shoulder 94 on'the piston rod 78 and is held in placeby 'a key 95. The stop plate 90 fits over a pin 96-m0unted in the end cap 82; and slides back and forth on it; This prevents the piston rod 78 from rotating. The other end of-the piston rod 78 supports a holder-98 'for-the air nozzle 16 which is keyed to it at 100. 'Thus the holder 98 and air nozzle 16 will beheld in position. The end of the piston rod 78 has a 'suitablecap-nut 102.screwed wit and a bellows or diaphragm 104,heldon each-side by suitable 0 rings 106, allows for-movement of the piston rod 78 and air nozzle 16 and holder 98 withoutleakage. It will be noted that a slight spacing exists,as at 110, between the faces of the stop pins 88and the stop plate 90. This is to say that thefaces of the pins 88 are spaced just slightly farther apart than the thickness 'of the stop plate 90. Thus, the piston rod can move back and forth by an amount equal to the spacing 110. Movement of the piston rod 78 will move the nozzle holder 98 which inturn moves the nozzle 16.

The structure shown and described in relation toFIG- URE -4 may be the samefor both nozzle holders, although it has been specificallyset forth with reference totheupperno'zzleinFIGUREi f -Relat ing the FIGURES 3' and 4 structure to the- EIG- URES 1 and 2 structure, the air cylinder 76 formo'ving The use, operation and function of the inventiomare asfollows:

Whereas I have referred principally to a-double disk grinder, it should be understood that many, if not of the novel features may be appliedequally as'well to a single disk grinder. IWhethei" single or multiple, the

axis of the disk or disks 'may be vertical, horizontal, or otherwise. Also, I have stressed automatic dressing, and

it should be understood that the'dressing maybe any suitable nianual arrangement or semi-automatic. Additionally, the infeed of the disk or disks has been characterized as automatic, and-it should be understood that. it could be'manual. In this sense, the signal from the eontroller or controllers could energize a. suitable light bell, 'or any suitable manifesting device in response'tolwhich the operator could manually infeed, orenergize. theinfeed mechanism. 'Or any combination of the above could be used. 2

While the movable nozzles shown in FIGURE 4.are intended primarily to be used in conjunction with automatic dressing, it should be understood that the nozzles in FIGURE 1 could be adjustably mounted, tobe adjusted by hand and preset for any p rt cular-grinding operation. But when grinding or dressing, the nozzle or nozzles would be considered fixed. This is true ofjeither a single or multiple disk grinder. V In the past, anrair nozzle has been .usedagainst the periphery of the grinding wheel in acenterless grinder, but the nozzle was moved toward the grinding whe el,. as the wheel broke down, along with a regulating or work positioning wheel. This could not be used'in a disk grinder since it would involve a complete qtlfirhaul of the article feeding mechanism, be it a rotary "or through feeder or what have you, as well as extreme complication 'in adjusting the related mechanism.

Accurate positioning of the grinding wheels has proved particularly troublesomein thepast. This is particularly true of double disk grinders in which the sides v.orfaces of the wheels are used for grinding instead of the periphery. The faces are closely spaced andare opposite each otherand the work may be sheared .or 'passedbetweefn the grinding faces. Asthe faces breakdown, the, wheels -are fed inwardly toward each'other togcompensate'ffor jwheel wear. In the past, hardened feeler vlingers or indirectnreasuring gauges have been used to feel, or 'sense'the' position ofthe wheel face followed by somesortiof, an-infeeding mechanism to compensate for wheel wear; :ButYt'hisirivolves physically touching the wheelface .wliichjnevip ably results in wear on the item being contacted erjin some indirect method such as gauging the'workpiece or otherwise. i

.I would prefer that the air nozzles belocated well within the periphery of the grinding disks, forle'xample on the orderof 1 /2 inches so that the jets .willimpinge against the disk faces beyond or inside ofthearea atthe peripheral edge which is broken down rapidlyiduelto shearing in of the workpieces. I also prefe'r'thatthe nozf- :zles be positionedbehind or" on the back side of, the-disks, relative to the'iside where the workpieces are introduced, and ,below the center .line of the disks. .Thisinightfiibe referred to as in the rearrlowerlquadrant. -Ihepoin thatin' a double disk grinder, the'disks maybetilte'd back slightly in the case of a push-through feeder, and tilted both back and down in the case of a rotary feeder. In either case, the rear lower quarter is aifected the least and, accordingly, any such tilting or a combination thereof would have the least effect in the rear lower quarter of the disks.

In a double disk grinder where automatic dressing is highly desirable, gauging directly from the wheel faces is very important since once the gauging devices have been set, the dresser can be accurately positioned relative to the nozzles so that when the dresser is passed between the grinding faces, the machine, so to speak, will know exactly where the new faces of the wheels are. Or the nozzles can be set accurately relative to the dresser. But in either case when the faces of the disks have been dressed off, the new plane of the faces will be accurately established relative to some fixed part of the machine. In systems which gauge or check the workpiece, the spacing between the wheel faces may be checked by gauging the workpiece and when oversize, infeeding may take place. But an oversize workpiece does not tell whether or not the wheels have broken down at the same rate or differentially. In the event that one wheel has broken down much faster than the other, an automatic dresser would remove a substantial amount from the wheel that hadnt broken down and might miss or barely touch the other. But, in the arrangement shown, the dresser and nozzle can be accurately positioned relative to each other. Then the wheels can always be brought to the air nozzles or may be positioned in predetermined relation to the air nozzles just prior to an automatic dressing operation. This insures that the dresser will dress approximately the same amount off of each wheel. The dresser referred to above is of the type having oppositely disposed diamonds or the like spaced a predetermined distance apart and the dresser has not been shown in detail in the drawings since it is well known in the art.

While I have referred to the use of two nozzles, each of which checks the face of its wheel independently, it is quite feasible to use one nozzle and thereafter the workpiece could be gauged or checked which would accurately tell the precise position of the face of the other wheel.

In the arrangement shown, the nozzles are also movably mounted so that when the thrust of the quill cylinders is reversed at the beginning of a dressing operation, the nozzles will move in the same direction to prevent contact between the face of the wheels and the nozzles. This has the distinct advantage that in a machine of the type shown backlash may be eliminated during grinding, automatic dressing may be used, and the nozzles may be positioned between the grinding faces of the disks or wheels, all without needless complication with all parts operating or being tied in together.

While I have shown and described the preferred form and suggested variations of my invention, it should be understood that suitable additional modifications, changes, substitutions and alterations may be made without departing from the inventions fundamental theme. I, therefore, wish that the invention be unrestricted, except as by the appended claims.

I claim:

1. A method of positioning the grinding disks in a double disk grinder having grinding disks rotatable about an axis with opposed faces, including the steps of directing a controlled air current from a source against each of the opposed faces of the disks, positioning each source a predetermined distance from the face of its disk, moving each source along said axis away from its grinding disk when the face of its disk comes closer to the source than the predetermined distance to prevent contact between the face of each disk and its source, feeding each disk along said axis until the increase in air pressure in its controlled air current, due to resistance offered by the face of its disk, reaches a predetermined high value, and

thereafter feeding each disk along said axis toward the other, from time to time, as the air pressure in its controlled current drops to a predetermined low value due to the face of its disk being worn away during grinding to thereby maintain an accurate spacing between the disk faces.

2. A method of positioning the grinding disks in a double disk grinder which has two co-axially mounted oppositely disposed grinding disks to grind generally parallel faces on a work part passed between the opposed faces of the disks, including the steps of directing controlled air currents from adjacent sources against the opposed faces of the disks, one air current against the face of each grinding disk, directing the air currents in opposite directions from approximately the same point between the disk faces, positioning each source a predetermined distance from the face of its disk, moving each source along said axis away from its grinding disk when the face of its disk comes closer to the source than the predetermined distance to prevent contact between the face of each disk and its source, feeding each disk axially inward in opposition to the air currents, discontinuing the disk feed when the air pressure in the current, due to the proximity of the disk face, increases to a predetermined value, feeding work parts between the disks to grind generally parallel faces thereon resulting in the disk faces breaking down, and, from time to time, feeding each disk axially inwardly toward each other against the direction of the air currents when the air pressure in the controlled current drops a predetermined amount.

3. A method of positioning the grinding disks in a double disk grinder which has two co-axially mounted oppositely disposed grinding disks rotatable about an axis to grind generally parallel faces on a work part passed between the opposed faces of the disks, including the steps of directing controlled air currents from adjacent sources against the opposed faces of the disks, applying a pressure against each disk to urge the disks apart against fixed points, reversing the applied pressures to urge the disks together against an air current in excess of a predetermined value, moving the adjacent air current sources along said axis with the disks to prevent contact therebetween, reversing the applied pressures to urge the disks further apart to dressing position, dressing the opposed faces of the disks, feeding each disk axially inward in opposition to the air currents, and discontinling the disk feed when the pressure of the air in the current, due to the proximity of the face of each disk, increases to a predetermined value.

4. A method of positioning the grinding disk in a disk grinder in which the grinding wheel is constructed to be rotated about an axis and has a grinding face, including the steps of directing a controlled air current from a source against the face of the disk, positioning the source a predetermined distance from the face of the disk, moving the source along said axis away from the face of the disk when the face of the disk comes closer to the source than the predetermined distance to prevent contact be tween the face of the disk and the source, feeding the disk along said axis until the increase in air pressure in its controlled air current, due to resistance oifered by the face of the disk, reaches a predetermined high value, and thereafter feeding the disk along said axis, from time to time, as the air pressure in the controlled air current drops to a predetermined low value due to the face of the disk being worn away during grinding to thereby maintain the face of the disk in an accurate position.

References Cited in the file of this patent UNITED STATES PATENTS (@ther references on following page)

Claims (1)

1. A METHOD OF POSITIONING THE GRINDING DISKS IN A DOUBLE DISK GRINDER HAVING GRINDING DISKS ROTATABLE ABOUT AN AXIS WITH OPPOSED FACES, INCLUDING THE STEPS OF DIRECTING A CONTROLLED AIR CURRENT FROM A SOURCE AGAINST EACH OF THE OPPOSED FACES OF THE DISKS, POSITIONING EACH SOURCE A PREDETERMINED DISTANCE FROM THE FACE OF ITS DISK, MOVING EACH SOURCE ALONG SAID AXIS AWAY FROM ITS GRINDING DISK WHEN THE FACE OF ITS DISK COMES CLOSER TO THE SOURCE THAN THE PREDETERMINED DISTANCE TO PREVENT CONTACT BETWEEN THE FACE OF EACH DISK AND ITS SOURCE, FEEDING EACH DISK ALONG SAID AXIS UNTIL THE INCREASE IN AIR PRESSURE IN ITS CONTROLLED AIR CURRENT, DUE TO RESISTANCE OFFERED BY THE FACE OF ITS DISK, REACHES A PREDETERMINED HIGH VALUE, AND THEREAFTER FEEDING EACH DISK ALONG SAID AXIS TOWARD THE OTHER, FROM TIME TO TIME, AS THE AIR PRESSURE IN ITS CONTROLLED CURRENT DROPS TO A PREDETERMINED LOW VALUE DUE TO THE FACE OF ITS DISK BEING WORN AWAY DURING GRINDING TO THEREBY MAINTAIN AN ACCURATE SPACING BETWEEN THE DISK FACES.

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