US2508102A - Grinding - Google Patents

Description

May 16, 1950 J. A. CUPLER, Ir

GRINDING Filed Sept. 24, 1946 4 Sheets-Sheet 1 INVENTOR Jo/m 60, 466 1],

. BY Wm ATTORNEY J. A. CUPLER, I

GRINDING 4 Sheets-Sheet 2 ./0///V fl Kama 1,

BY M6? ATTORNEY May 16, 1950 Filed Sept 24, 1946 y 6, 1950 J. A. CUPLER, IL 2,508,102

GRINDING Filed Sept. 24, 1946 4 Sheets-Sheet 4 INVENTOR ATTORNEY Patented May 16, 1950 UNITED STATES PATENT OFFICE GRINDING John A. Cupler, II, Cumberland, Md. Application September 24, 1946, Serial No. 699,003

4 Claims. (01. 51-103) 1 Apparatus and methods for grinding currently in use, are largely dependent upon the accuracy of bearings, centers, regulating wheels and grinding wheels provided by the equipment for the ultimate tolerances attainable. Grinding contemplating the use of chucks or centers of the ordinary type, necessitate rotation of the work about the axis of an element which is not necessarily the axis of the work. Even in centerless grinding, it is customary to permit the work to float between a grinding wheel and a regulating wheel, in conjunction with which a support is frequently employed. In such centerless grinding techniques however, the work is again not necessarily maintained with its own axis aligned throughout the operation, since imperfections in the surfaces of the grinding wheel, the regulating wheel and/ or the support will vary the position of the work axis, as will any imperfections or eccentricities transmitted to any of these elements from their drives.

Whereas the development 01. the art has witnessed vast improvements, particularly during recent years, existing techniques will not permit the holding of such tolerances as are required for example in the production of drills having cutting portions whose diameters are of the order of up to several thousandths of an inch.

In accordance with the present invention, it is sought to provide apparatus and procedure adapted for the maintenance of such close tolerances, whether for the production of so-called microscopic drills and punches or for larger types of work in connection with which concentricity and overall accuracy are desired.

' This invention is particularly applicable for use on a work piece having a cylindrical surface and a second surface to be rendered coaxial therewith and is applied by peripherally driving the work piece about its cylindrical axis and simultaneously holding the work piece against axial displacement while operating on the surface to be rendered coaxial. The work support may provide a notch or bight, or a plurality of spaced notches or bights to receive a cylindrical portion of the work, such bights being defined for example by spaced pairs of elements defining substantially point contact for the work such as would be produced by spherical sections of relatively hard materials such as certain types of steel, or synthetic or natural diamonds or sapphires. The work is preferably rotated by a means frictionally engaging its periphery, such as a roller which may be grooved to form lands so as to maintain the work in the one or more notches or bights provided by the supporting means to assure its constant axial position during an operation. Where the driving roller is provided with lands, they are preferably spaced to substantially correspond with the spaced sup- 2 porting elements, thereby reducing bending tendenc es.

The supporting means for the work is preferably so disposed with respect to the axis and direction of,rotatlon of the driving means that upon engagement of the driving means with the work, the latter is biased towards a stop whose position may be adjusted so that the axial position of the work piece will be established at the beginning of an operation and maintained throughout the operation. This result may be produced by a relatively small displacement of the axes, which may exist with respect to only a single plane. The work engaging means or driving roller is preferably supported for swinging movement about a remote axis to permit insertion and removal of work with facility, the drive for the roller being so arranged that its rotation can continue even while it is disengaged from the work piece.

The work piece supporting means or compound is preferably adjustable with respect to a plurality of axes so that the work piece can be assigned any one of a plurality of positions with respect to a tool. Such adjustment may be rectilinear in some cases and arcuate in others, depending upon the desired relationship to be established between the work piece and the tool. Where the invention is applied to operations with drills or rotary reamers for example, the shank of such element is preferably cylindrical for cooperation with the supporting means and frictional engaging means, the cutting portions of the element projecting beyond the frictional engaging means to operate on a member or be operated on by a tool.

The tool which performsthe operation on the work piece may be a grinding wheel, the direction of rotation of which may correspond with that of the frictional engaging means or roll. and the two may be rotated by independent power sources where desired. Means may also be provided for reciprocating the grinding wheel with respect to its own axis and preferably in its own bearing in orderto maintain such axis constant in space. The reciprocation of the grinding wheel may be effected by a cam acting upon an extension of the grinding wheel shaft, which cam may be rotated by an independent driving means or a driving means employed for one or both of the grinding wheel and driving roll.

A more complete understanding of this invention will follow from a detailed description of the accompanying drawings wherein:

Fig. 1 is a plan of apparatus in accordance with the present invention;

Fig. 2 is a front elevation partially in section of the apparatus shown in Fig. 1;

Hg. 8 is a sectional elevation taken along line H of H8. 1;

Fig. 4 is an elevation, partially broken away, showing the right end of the apparatus of Fig. 2;

Fig. 5 is an elevation of a portion of the work piece support, enlarged for greater detail; and

Fig. 6 is'a plan of the portion of the work piece support depicted In Fig. 5.

The apparatus has been depicted in. the drawings as supported upon a base or table Ilby means of a grinding wheel frame I2 and a compound pedestal ll. The grinding wheel frame accommodates a pair of spaced bearings II secured therein by cooperating sleeves II and 20, the former of which is threaded to receive a nut 22 for drawing the complementary frustroconical surfaces of the sleeves into binding relationship. The grinding wheel shaft 24 is received in these-bearings for rotation by means of a pulley 2 fixed to a reduced extension 28 thereof and driven by a belt II from a motor 22 located below the table, and reciprocated therein by means of a cam 34 bearing against a ball I. received in a bore it formed in the reduced end of.the shaft. The opposite end of the shaft 24 is provided with a similar bore I. which receives a ball 42 for bearing against a plunger 44 telescopically received in a sleeve 40 and biased against the ball 42 by means of a coil spring 48 whose other 'end bears upon a reduced shoulder II in the sleeve. The sleeve 40 is supported in a bracket 52 suitably mounted on the table It, a suitable key or set screw 54 in the bracket cooperating with a key-' way 56 formed in the outer surface of the sleeve to prevent relative movement of the sleeve with respect to its brackets. The plunger 44 is provided with a reduced portion Ill projecting entirely through the sleeve and terminating in a threaded portion II for receiving a limiting nut 82 and a lock nut 04.

The cam 24 is fixed to a shaft 66 which is driven by means of a motor 8|, pulley 1|, belt I2, pulley I4 and gear reduction box It, the details of which have not been illustrated.

An enlarged section 18 of the shaft II receives a pair of threaded collars ill and 02 provided with cooperating threads 84 for clamping the opposed radial surfaces of the collars against the two radial surfaces of a grinding wheel I. The grinding wheel being thus fixed with respect to its shaft, will partake of the rotary movement imparted to the shaft through the pulley 26 of an axial reciprocating movement imparted thereto by the cam 34. It will be clear that the relative rates of these two movements screw I02 to position a diamond type or other suitable wheel dressing material when it is desired to true the grinding wheel or modify its contour.

A compound I supported on the pedestal I is rendered arcuately adjustable by means of a v pair of screws I05 whose threaded ends are recessed to receive balls I" applied against a bearing lug I'Il projecting forwardly from a table III integral with the pedestal. The screws I are carried by a plate III which is suitably attached to an arcuately adjustable slide III to provide for arcuate adjustment of the work piece with respect to the table III. A longitudinal slide 2, adjustably supported by the slide III, may have its position adjusted by manipulation of a screw III and a superposed transverse slide III is adjusted by means of a screw I I8. The transverse slide III in turn supports a plate I20 which is rendered vertically adjustable with respect thereto by means of a wedge I22 which is advanced or retracted by means of a screw I24, contact between the wedge and plate being maintained under the force of a spring I26 engaging the head of each of the one or more bolts I2. extending through the plate I2l into the trans-v verse slide. A work piece holder or support I" is received in a sleeve I32 carried by the plate I20 and retained therein by means ofa set screw Ill. One end of the work piece support is threaded to receive a screw I" having a re;

ferent types of work, different types of grinding .wheels and other factors which may be encountered. It will also be clear that the shape of the cam may be modified to produce different modes of reciprocation. The bearings and their retaining sleeves have been depicted as having radial ports through which lubricants may be introduced from suitable sources ll which have been depicted as of the adjustable type well known in the art. Moreover, a stationary tool may be employed.

These lubricators .8 are shown as threadedly received in bearing caps 90 secured to. the frame by suitable bolts 02.

Mounted on the table II behind the grinding wheel, there is provided a compound 94 having a longitudinal slide I adjustable by means of a thumb screw 08, upon which is mounted a transverse slide Ill adjustable by means of a thumb duced end I 38 which functions as a stop for the work piece I, a head I42 for adjustment of the stop and a locking nut I to maintain the stop against accidental movement.

As depicted in Figs. 5 and 6, the work sup.- porting portion of the member I32, corresponding with the right hand portion of Fig. 2, has a substantially plane upper surface I carrying two spaced pairs of bight forming elements I ll whose substantially spherical or partially spherical surfaces provide four substantially point contacts for the work piece. It will be noted especially with reference to Fig. 6, that in the horizontal plane, a line passing through the bight of the two pairs of balls or the like is slightly angularly displaced with respect to the center line of the work piece support itself. The angular displacement is depicted as being of the nature of two or three degrees, the numerical value of which is not critical so long as it serves to pro-- vide a biasing of the work piece against the end of the stop which in assembled relationship occupies a po--tion of the groove I50 shown in Fig. 6. The manner in which this biasing effect is produced rem; ins to be described.

A pair of brs ckets I52 serves to journal a frame I for pivotal movement with respect to the plate I2l about the axis of a shaft I58 rotatable in the frame. A portion of the shaft I" extends beyond the frame to receive a bevel gear I58 in mesh with a similar bevel gear I carried at the end of a transmission shaft I62 containing a pair of universal joints I64 and I I. the transmission shaft being driven through a gear reduction box I68, a pulley I10, a belt I12, a pulley I14 and a shaft I" from a motor I".

The shaft I" mounted in the frame I" has a spur gear I" secured thereto through which it drives a similar gear I82 secured to a parallel shaft Ill likewise journaled in the frame I". An end of the shaft I projects through a side of the frame II to receive on its end, a roller Ill whose periphery is provided with a groove Ill defining lands I which are spaced in substantial correspondence with the spacing between the pairs of bight forming elements I48 arranged therebelow on the work supporting member I46. be defined by a friction material such as a rubber composition or any other type of friction surface such as would be provided by a fine grit grinding wheel, having a plain or grooved periphery so that when its edge engages the periphery of the work piece, the latter will be rotated in a direction opposite to that of the roll, the roll and the grinding wheel 88 preferably having the same direction of rotation. Inasmuch as the axis of the shaft I84 and the roll I86 is parallel with the axis of the work piece support I32 as depicted in Fig. 6, the roll axis will be slightly displaced from the work piece axis because of the arrangement of the bight forming elements. whereby rotation of the roll in contact with the periphery of the work piece will bias the end of the work piece against the stop I38 so as to position the work piece axially during a grinding operation.

When it is desired to insert a work piece in the apparatus, the frame I54 can be lifted by means of its handle I82 to swing about the axis of the shaft I58, whereupon the work can be introduced between the bights of the supporting elements, the slot I94 shown in Fig. 6 as formed in the work support between the pairs of bight forming member, facilitating the introduction and removal of a small piece of work by means of tweezers or the like, or a larger piece of work by a correspondingly larger and suitable implement or by the hand of the operator.

Having inserted a work piece, the frame I54 can then be lowered to the position shown in the drawings whereupon the lands of the roll will engage the periphery of the work piece immediately above the bight forming elements to rotate the work piece and drive its end against the stop. The introduction of a work piece is preferably eifected while the grinding wheel is at a distant portion of its reciprocating stroke so that by the time the grinding wheel advances suflicientlyto engage the work, the work piece will have assumed its rotary motion and will have been biased against the stop.

A suitabie coolant may be supplied from a tank and pump assembly I98 arranged below the table and connected by means of suitable tubing I88 with a vertical pipe 208 and through a valve 202 for controlling the flow and suitable fittings to a goose neck 204 which may supply the coolant to the groove of the roller I88 or to some other appropriate point in that vicinity.

It will be clear that by suitable adjustment of the work support compound, a variety of operations can be obtained whereby the apparatus can be used for cylindrical grinding, back taper, flat grinding or facing, and the work can be moved to assume almost any desired angle with respect to the grinding wheel or other tool which may be substituted, and if it is desired to insert a drill on the work support, the type of drive herein described might well be used to perform a drilling operation. The apparatus may be used for operating on many types of work including breaches, punches, and other types which will readily suggest themselves to those skilled in the art. Provisions may be made for driving the various motors at speeds ranging from zero to their maximum values and it is contemplated that the use of known types of transmissions The surface of the roll I85 may 4 would permit the use of fewer motors or other power sources.

Whereas but one embodiment of the invention has been described with reference to the accompanying drawings, it is not intended that the invention be restricted thereto beyond the scope of the appended claims.

I claim:

1. Grinding apparatus comprising means pro viding a plurality of pairs of contacts each fixed with respect to the others for supporting a work piece for rotation about its own axis, means for frictionally engaging peripheral portions of said work piece substantially opposed to said contacts to rotate the same, said supporting means and engaging means providing means to maintain axial alignment of the work piece, a grinding wheel rotatable in a plane displaced from said engaging means for operating on a portion of said work piece projecting beyond said engaging means, and means for driving said engaging means and grinding wheel.

2. Apparatus comprising spaced pairs of elements having substantially spherical surfaces for supporting a work piece for rotation about its own axis, means for frictionally engaging a peripheral portion of said work piece to rotate the same, said supporting means and engaging means providing means to maintain axial alignment of the work piece, a tool disposed in a plane displaced from said engaging means for operating on a portion of said work piece projecting beyond said engaging means, and means for driving said engaging means.

3. Apparatus comprising means providing a plurality of substantially point contacts each fixed with respect to the other for supporting a work piece for rotation about its own axis, means for frictionally engaging a peripheral portion of said work piece to rotate the same, said supporting means and engaging means providin means to maintain axial alignment of the work piece, a tool disposed in a plane displaced from said engaging means for operating on a portion of said work piece projecting beyond said engaging means, and means for driving said en-- gaging means.

4. A method of grinding a work piece having a cylindrical reference surface comprising supporting said reference surface at a plurality of points spaced circumferentially and along the axis thereof, drivingly engaging said surface opposite said points of support to thereby rotate said work piece relative to said points, biasing said work piece to a position axially fixed with respect to said points. and grinding a portion of said work piece.

JOHN A. CUPLER, II.

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

UNITED STATES PATENTS

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