US2246023A - Grinding machine - Google Patents

Description

' June 17,1941.

B, c. SPURLING GRINDING "MACHINE Filed Sept. 11, 1940 5 Sheets-Sheet 1 June 17, .1941. B. c. SPURLING 7 2,246,023

GRINDING MACHINE 7 Filed Sept. 11, 1940 5 Sheets-Sheet 2 June 17, 1941. c, S URUN 2,246,023

GRINDING MACHINE I Filed Sept. 11, 1940 5 Sheets-Sheet 3 a Q. v v i l fin M r i M. W fix. g, m

June 17, 1941. c, SPURUNG 2,246,023

GRI-NDING' MACHINE Filed Sept. 11, 1940 5 Sheets-Sheet 4 I l v Juie 17, 1941. P R NG 2,246,023

GRINDING MACHINE Filed Sept. 11, 1940 5 Sheets-Sheet 5 Patented June 17, 1941 leaf T I Gamnnic. Manama Bertram Charles Spurling, deceased, late of Leicester, England, by Mildred Ann Spurling, administratrix, Leicester, England, assignor to The Bentley Engineering Company Limited, Leicester, England, a British company Application September 11, 1940, Serial No. 356,388 In Great Britain December 24, 1938 goi. 51-109) 13 Claims.

This application corresponds to the application of Bertram Charles Spurling and The Bentley Engineering Company Limited, Serial No.-

ular outline can be ground with accuracy. It

is well known to grind profiles in blanks by causing a carriage which holds a blank to move in a suitable path determined by a pattern while holding the blank against a grinding wheel.

According to the present invention a grinding machine comprises in combination a grinding wheel and a carriage somounted as to be free to move in any direction parallel to an imaginary plane of reference which is itself parallel to the grinding wheel axis but not away from said plane, a support for attaching a master pattern to the carriage, a support on the carriage for holding a blank tobe ground in line with the master pattern in a direction normal to the said plane parallel to which the carriage is movable and presenting it to the grinding wheel, and a stationary guide in line with the grinding wheel in a direction normal to the said plane to engage the profile of the master pattern, so that the carriage can be moved parallel to the said plane to cause the pattern to traverse the guide and thus cause the grinding wheel to reproduce the pattern on the blank.

Other features of the invention will be more clearly understood from the following description of a preferred example of the invention taken in conjunction with the accompanying drawings, in which Figure 1 is a perspective view of the apparatus according to the invention;

Figure 2 is a plan of the mechanism illustrated in Figure 1, a portion being broken away for the sake of clearness, and is a section on the line 2-2 of Figure 3;

Figure 3 is an elevation of the apparatus shown in Figure 2, parts being shown in section;

Figure tv is a section on the line 44 of Figure 2;

Figure 5 is a section on the line 55 of Figure 2;

Figures 6 and 7 show in elevation a truing device used in conjunction with the grinding wheel, and

Figure 8 is a plan of the device shown in Figure 7.

Like reference numerals indicate like parts in the several figures of the drawings.

The grinding wheel I t is mounted to rotate about a horizontal axis in a fixed grinding head indicated as a whole by the reference numeral On a horizontal plane, at a level.

II in Figure 1. below that of the grinding wheel, is a fixed table I2 whichsupports the carriage l3 already mentioned. Between the carriage and the table l2 are ball, roller or other anti-friction devices enabling the carriage to be movable with freedom in all directions in its own plane. In the example shown these antifriction devices comprise a series of balls I4 mounted between outer race *rings I5 and inner race rings, not shown, which latter are secured to the under side of the carriage l3. The carriage can therefore move in any direction parallel to an imaginary plane oi, reference the direction of which is determined by the table I2 so as to be parallel to the grinding wheel axis.

' Adjustable on the carriage is a support for a master pattern It and this support conveniently takes the form of a shallow channelled member H which constitutes the upper member of what is virtually a compound slide rest. The master pattern can be held in the channel by means of bolts IE or the like and the member I! is formed on its under side with a key or guide H! which is guided in a corresponding groove in a companion member 20 lying beneath it. A lead screw 2! rotatably mounted at 22 in an overhanging portion 23 of the member I1 is so. mounted that while it is free to rotate it is in-.

capable of endwise movement relatively to the part 23. The lead screw itself engages within a correspondingly threaded recess in the slide member 20 so that by rotation of the lead screw 2! the member I! can be adjusted towards and away from the grinding wheel. The slide member 20 is formed with side flanges engaging above a slide or guide portion 24 formed on the base of the carriage I 3. The flanges on the member 20 and the guide portion 24 are formed I to guide movement of the slide 20 in a direction at right angles to the movement of slide I9, and the position of slide 2!] on the guide 24 is controlled by means of lead screws 25 situated on each side of the member 20. The lead screws 25 are threaded into correspondingly threaded orifices extending laterally through bearing brackets 26 formed integralwith and uprising from the base member I3, and the inner ends of the lead screws 25 abut against the sides of slide member 20.

The brackets 26 support a strong square-sectioned cross member 21, portions of which are cylindrically ground to be carried in bearing sleeves 28 mounted in the upper portions or brackets 26. The bearing sleeves 23 are oppositely tapered as clearly shown in Figure 3 and are held in position by means of nuts 29 each of which is threaded on to the inner end of its sleeve 28 so as to bear against the adjacent surface of bracket 26. The central portion of the cross member 21 is specially shaped as shown clearly in the drawings to afford a rearwardly' extending bracket I29 from which rise upstanding lugs 36. Mounted on the bracket I29 in any preferred manner or formed integral with it is a cradle 3| of semi-cylindrical form and in this cradle is carried a two-part work-holder, the lower member 32 of which has its outer surface shaped to conform to the inner surface of the cradle 3|. The outer member 33 of the workholder is mounted in the lower member 32 so as to be capable of sliding in guides therein towards and away from the grinding wheel and if a curved workpiece is to be ground the extremities of the upper work-holder are curved or relieved as at 34. In order to se'cure the two-parts of the work-holder in their adjusted positions, a set screw 35 is screwthreaded into the part 32 and its shank passes through an arcuate slot in the cradle 3| to permit the part 32 to be rocked in its cradle and clamped inany position ofadjustment; and another set screw 35 passing through a slot 31 in the member 35- is screwthreaded into the member 32'.

The workpiece is shown at 33 and a quickrelease device for holding the workpiece in position is constructed as follows: A lever 39 is pivoted between lugs 30 about a pivot pin 40. Screwthreaded into and passing through one end of the lever 39 is an adjustable locking screw 4| and engaging with the opposite endof the lever is a toggle lever 42' pivoted on a pin 43 mounted between lugs 44 extending upwardly from the bracket I29. In the position shownin Figure 4 the toggle lever 43 has been moved downwardly by pressure on a finger-piece 45 so as to force the left-hand end of lever 39 upwardly and thereby to depress the locking screw 4-! into firm contact with the workpiece 38= to hold it on the upper member 33 of the workholder. Previously to clamping the workpiece in position the lower member 32 of th work-holder has beenadjusted in cradle 3| to any desired position of angular adjustment. In Figure the quick-release device is shown in its released position for removal ofthe workpiece.

Mounted in the table I2 is a block 46 carrying a vertical cylindrical guide 41, the axis of which is tangential to the periphery or the grinding wheel and is situated in a position to be engaged by the profile of the master pattern.

It will be seen that in the construction described the carriage l3- can be manipulated by hand, as in the case of any copying machine tool of this type, to maintain the profile of the master pattern in engagement with the fixed guide 41 and by so doing the workpiece. 38 clamped in position: above the master pattern will be ground to receive a finished'profile which is an exact copy of that of the master pattern.

By'adjusting the work-holder in cradl 31' the edge of the profile of the workpiece cam be r'elieved, the degree of relief being dependentup'on the angular adjustment of the work-holderin the cradle. The latter bears on its end surface graduated markings to which a fixed pointer on the corresponding end of the member 32 can be set.

The lower slide rest I1, 20, 24 for carrying the master pattern enables an initial adjustment of the position of the master pattern to be made in its setting in the carriage l3.

The carriage may, instead of being mounted for manual movement, be combined with any means by which it may be mechanically or otherwise moved as may be found. most convenient.

Th work-holder can also be adjusted about the axis of the cross member 21 for which purpose one end of the cross member extending through the left-hand bearing shown in Figure 3 is screwthreaded as at 56 and a locking wheel 51 engages with the screwthread 56, a pressure washer 58 being interposed between the boss of the locking wheel 51 and the outer extremity of bearing 28. The latter is conically formed to engage with a conical recess in the pressure washer. Thus, by loosening locking wheel 51 the cross member 2-! can be angularly adjusted to its desired position and the degree of adjustment will be indicated by graduated markings formed on the outer surface of the washer 58 as shown in Figur 1-, and these markings can be set against a fixed pointer 59 attached to bracket 26. The washer 58 is caused to turn with the cross member 21 and for this purpose is keyed at 60 to the cross member 21. Thus, to adjust th angular position of cross member 21 the locking wheel 57 will first be loosened, the cross member 21 and the parts it carries will then be adjusted with reference to th fixed pointer 59 after which the locking wheel 51' will again be tightened and the parts will be held firmly in their position of adjustment.

In order to true the grinding wheels from time to time the device illustrated in Figures 6 to 8 is conveniently employed.

Th truing device proper comprises a bracket as mounted to rotate on fixed guide 41, the parts being carefully machined so that as little play as possible exists in the mounting. Fixed to and extending upwardly from bracket 48 is a standard 49 having a head 5!! in which is secured a diamond cutter 51-. The latter is conveniently carried at the end of a micrometer screw 5'2 passing completely through the head from. front to back and held in an adjusted position by means of a set screw 53. A handle 54 is screw-threaded into bracket 43 to afford means for swinging the bracket: about the fixed guide 47. It will be appreciated that if the cutting point of the diamond Si is set in vertical alignment with the outer surface of fixed guide 41 and the bracket 38- is swung: from side to side about the axis of th guide W, the edge of the grinding wheel will be true to a curvature conforming exactly with the curvature of the guide 41'. As is well known, the grinding wheel may be so mounted that it can be fedtowards the truing tool for truing purposes.

In order to set the position ofthe diamond the bracket 48- can" be passed over another rod 55 set apart from the machine and having the same diameter as that of the fixed guide 41.

The height of rod 55, however, will be sufiicient toextend upwardly beyond the point of the diamond cutterso that the latter can be brought into contact with the surface of rod 55; whereupon the set screw 53 willbe tightened to hold the diamond in the position thus set.

This will ensure that when the bracket 48 is transferred on to fixed guide 41 the vertical alignment of the diamond cutter and the outer surface of guide 4'! will b ensured.

What is claimed is:

1. A grinding machine comprising in combination a rotatable grinding wheel and a carriage, means mounting said carriage for movement in any direction parallel to and at a fixed distance from an imaginary plane parallel to the grinding wheel axis, a support on the carriage for attaching a master pattern thereto out of the plane of the axis, a support on the carriage for holding a blank to be ground in a position for presentation to the grinding Wheel in line with the master pattern in a direction normal to said imaginary plane and in the plane of said axis, and a stationary guide positioned -to engage the profile of the master pattern, in

lin with the grinding wheel periphery in a direction normal to said plane, whereby movement of the carriage parallel to the said plane will cause the pattern to traverse the guide and cause the grinding wheel to reproduce the pattern on the blank.

2. A grinding machine as claimed in claim 1 in which the support for attaching the master pattern to the carriage comprises crossed slides on the carriage and means to individually adjust said slides so that the master pattern may readily be positioned to any desired relationship with the means for holding the blanks.

3. A grinding machine as claimed in claim 1 in which the support for holding the blank includes means adjustable in relation to the carriage about two axes at right angles to each other, one of said axes being at right angles to the axis of the grinding wheel when the carriag is in its normal relation to the wheel.

4. A grinding machine as claimed in claim 1 wherein the support for holding-the blank is mounted on a shaft, means rotatably supporting the shaft from the carriage with its axis parallel to the plane of reference of the carriage-movement, and parallel to the grinding wheel spindle.

5. A grinding machine as claimed in claim 1, including a quick-release device associated with the support for holding the blank thereon for the purpose of clamping and releasing the same as desired.

6. A grinding machine as claimed in claim 1, wherein the mounting means for the carriage is a flat supporting plate, whereby universal movement thereof is eifected by moving the carriage over the plate.

7. A grinding machine as claimed in claim 1, wherein the supporting means for the carriage is a fiat plate, and antifriction bearing members interposed between the supporting plate and the carriage.

8. A grinding machine as claimed in claim 1, wherein the supporting means for th carriage is a flat plate, and ring ball bearings interposed between the carriage and the supporting plate.

9. A grinding machine as claimed in claim 1 in which the support for the blank comprises a cylindrical cradle mounted on said carriage and a corresponding cylindrical Work-holder adjustable therein, rthe axis of the cylinder being normally disposed at right angles to the axis of the grinding wheel, for the purpose described.

10. A grinding machine comprising in combination a grinding wheel rotatable about a fixed axis, a fixed flat supporting plate having an upper surface parallel with the axis of the grinding wheel, a carriage mounted on the supporting plate for movement in any direction over the surface thereof, means on the carriage for adjustably supporting a master pattern, a guide having a guiding surface positioned so as to be capable of engagement with the master pattern and extending in a direction at right angles to the supporting plate and tangential to the edge of the grinding wheel, a cradle upon the carriage including clamping means for a blank to hold the same for grinding by said wheel and means adjustable to cant the blank, one of said means being adjustable about an axis parallel to the supporting plate and the other about an axis at right angles to the wheel axis so as to present the blank to the grinding wheel at any desired inclination while keeping the master pattern engaged with the stationary guide.

11. A grinding machine as claimed in claim 10 including a quick-release device associated with the cradle for holding the blank thereon for the purpose of clamping and releasing the same as desired.

12. A grinding machine as claimed in claim 10, including anti-friction members inserted between the supporting plate and the carriage.

13-. A grinding machine as claimed in claim 10, including ring ball bearings inserted between the supporting plate and the carriage.

MILDRED ANN SPURLING, Administratria: of the Estate of Bertram Charles Spmling, Deceased.

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