US2253324A

US2253324A - Grinding machine

Info

Publication number: US2253324A
Application number: US165565A
Authority: US
Inventors: Raymond H Cramer
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1937-09-24
Filing date: 1937-09-24
Publication date: 1941-08-19
Anticipated expiration: 1958-08-19

Description

`Allg. 19, 1941. R, H, CRAMER V2,253,324

GRINDING MACHINE Filed Sept. 24, 1957 2 Sheets-Sheet 1 Aug. 19', 1941. R, H. CRAMER 2,253,324

' GRINDING MACHINE Filed Sept. 24.1937 2 Sheets-Sheet 2 /NVE/v fof?. RAYMOND H CRA/VER,

Patented Aug. 19, 1941 .UNITED I STATES ENT i GFF ICE GRINDING Raymond H. Cramer, Newark,A N.\J.,` assigner to VGeneral -Motors Corporation, Detroit, Mich., a corporation of `Delaware F h A h Application septmiier 24, 1937, serial No. 165,565

5 claims. (orsi-icm This invention relates` to grinding `machines and; methods and comprises all of the features and aspects `of noveltyherein disclosed. In centerless grinding bythethrougn feed method, roundness of the; Work is improved by passing the` work several times through the grinding zone, the` position of the `Work bladek being different for successive passes. In ,other Words, the work is initially ground above or belowthe line ofcenters of the grinding andthe regulating Wheels, lO olutiona'ccurately generated by the machine. the subsequent passes being successively nearer The numeral indicates a support or bed which to the line of centers. This requires either sevis oscillated around a vertical axis I by any eral machines each with adiflerent setting or a suitable mechanism. A base plate l2 having a series of set-ups for one machine. g standard I4 is secured by :bolts I6 tothe bed An object of the invention is to provide an iml and has a bearing I8` for a` rotating shaft 2U. proved grinding machine and method for com- One end ofthe shaft is reduced in diameter and pletely finishing a surface of revolution in a single carries a Worm Wheel 22 driven by a Worm 2li pass through the grinding zone and obtaining a, held between thrust bearings on a horizontal progressive true roundness of the generated surshaft 26' which is journalled in bearing lugs 2B face in any plane normal to the axis of the piece.` onthe standard. A pulley 30 drives the shaft 2t Another object is to provide an improved grindand, through the yWorm, gearing, turns the shaft ing machine and method for acurately generat- Z-Uclockwisevat lovvI speed, say two revolutions per ing a contoured surface of revolution on a round minute.H A flange `32 on the rear of -the` shaft is Work-piece. Another object is to providea grind ,v secured by bolts 34 toa rotary feeding wheel orV ing machine in which the advantages of oscillat- 2? carrier 3,61Whichis dished to forni-a recess 38 reing and centerless grinding by the infeed method ceivingthe end of va" shaft carrying a regulating are combined. Y 4 WheelllZ-'Whoseperipheral surface is contoured to To these ends and also to improve generally t thework W which in this instance is a barrel upon machines and methods of this character, shape'droller. Theshaft, ll is journalled in a the invention consists in the various matters 30 bearingMi` on a standard 48 Whose base is slidhereinafter described and claimed. In its ablyfadjustable transversely of the shaft in a broader aspects, the invention is not necessarily slideway 5l] carried on the .oscillating bed. limited to the specific ,constructions and steps A narrow standard 52` is secured by bolts 54 to selected for illustrative purposes in the accom-v ,u the bed@ at aj point near the axis I il of oscillapanying drawings in Which- 'f5-J tQI1.` The upper portion of the standard is re- Fig. 1 is alfront elevation of the machine with cessed opposite to the periphery ofthe carrier 36 some parts broken away and some in section. towljeeive a removable guide or thrust plate 5t Fig. 2 is an end elevation of Fig. l With the Whi'chlisfastened by "screws 58. Opposed to the grinding Wheel removed. y regulatingvvheelto form Va converging grinding Fig. 3 is a plan View of a portion of the mathroatis a grinding Wheel Whose periphery is chine, the feeding wheel being in section. contoured like` that of the regulating Wheel and Fig. 4 is a side View of a portion of the feeding the work. The grinding Wheel rotates downwheeL Wardly atthe work at high speed and the regulat- Fig. 5 is an end view of Fig. 4. 4 3 ing-Wheel rotates upwardlyA at the Work atmuchL Fig. 6 is a side View of a portion of a thrust plat-e.

Fig. 7 is a plan View` of a Work supporting blade.

Fig. 8 is a front vieW of Fig. 7.

Fig. 9 is a right hand end view of Fig.. 8.

Fig. l0 is a view similar to Fig. 8, the blade beespecially adapted to grind the peripheries of i' barrel-shaped rollers for bearings but it will be understood that the machines can readily be adapted to generate concave, convex, conical or other surfaces of revolution on a variety of objects.V Such rollersproduced by cold heading or by turning lathes, for instance, are preferably end ground to accurate length tolerances with the-end faces flat and normal to the axis. These pieces are then ready to have the surface of revlovver""speed.` Both wheels areI adjustable to- Wards the axis of oscillation to ,provide for wear, thegrinding Wheel having a suitable slide (not shovvfforthis purpose.A Preferably, all of the nartsdescribed except the grinding Wheel oscil late as a'unit around the vertical axis lt through a short a'rc,the` broken line position of Vthe, grindinghhvvheel,in"` Fig. 3 indicating the relative oscillation `which occurs between the grinding wheel onthe" one' hand and the remaining parts on the other hand. The axis' of oscillation is in the lplane of the grinding wheel and passes through the center of transverse curvature of the grinding wheel periphery.

The carrier 36 (see Figs. 4, 5 and 1l) has its periphery provided with a series of equally spaced teeth alternating with notches 12. The carrier preferably moves down at the grinding throat and the leading face 14 of each tooth is substantially radial or parallel to a closely adjacent radius. The face 14 lies at right angles to the bottom wall '|6 of the notch While the rear face 18 of each tooth is perpendicular to the bottom wall 16 and parallel to the face 14. Extending perpendicularly into each bottom wall 16 is a tapped opening 80 for a blade fastening screw as will appear. That side of the carrier facing towards the thrust plate 56 has a flat annular face outside of a circular rib 82 to receive and support a toothed guide or thrust plate 86, see Fig. 6. The thrust plate 86 may be in the form of a single ring or may be in segments and it is removably attached to the side face of a carrier by screws 84. 'The thrust plate 86 has a series of teeth 88 alternating with tapered notches 80.

The rear faces 92 of the teeth 88 substantially -v coincide crosswise with the rear faces 'I8 of the carrier teeth and each tooth 88 covers one side of a tooth 16 and a portion of an adjacent notch l2. The bottom wall 94 of each notch 96 is straight and substantially aligns with the bot- Y' tom wall 16 of a carrier notch 12. The leading face 96 of each tooth 88 slants at, say 25, to a radius.

A work supporting blade is removably carried in each notch and comprises an attaching or supporting portion |88 of rectangular section secured by a screw |82 entering the tapped opening 88. The portion |60 of each blade ts the tooth faces 14 and 18 and the bottom wall 16 of a notch l2. A narrow section |04 of each blade is of the same thickness as the toothed thrust plate 86 and fits a tapered notch 9U of the thrust plate 86, thev narrow section of the blade having an upper wall |66 provided with the same inclination as the face 95 and engaging the latter. The blade has an extended portion |08 projecting laterally beyond the plate 86 over the regulating wheel periphery and into the space between the grinding wheel and the regulating wheel where it is provided with an upwardly and inwardly facing or bevelled surface ||0 which is laterally contoured to conform to the work. The outer surface of the blade is curved as at ||2, the center of curvature preferably being at the axis of oscillation and this places the work supporting portion of the blade close up to the contoured periphery of the grinding wheel 66 and just outside of the periphery of the regulating wheel 42. The work is conveniently supplied to the carrier from a magazine indicated at |4 and preferably arranged above the grinding throat and terminating near the top of the thrust plate 56.

As the feeding member or carrier 36 slowly turns clockwise, a work-piece W drops onto each contoured and inclined blade surface ||0 between the xed thrust plate 56 and one of the teeth 88 of the rotary thrust plate 86, the two thrust plates being parallel and spaced slightly farther apart than the length Vof the work and actingr as guides for the end faces of the work. The next piece is held back by the curved surface ||2 of the next blade until the carrier turns enough to let such next piece drop onto that next blade. The carrier moves each piece slowly down sidewise while supported by the blade and the regulating wheel, the piece being rotated by contact with the regulating wheel which is moving in a direction opposite to that of the carrier. As the piece moves down to the grinding throat it is gradually ground to size, the carrier, thrust plates and the regulating wheel making several oscillations as a unit while grinding occurs. The carrier rotation may be intermittent if desired and the movement is desirably fast while the work is brought to grinding position and then slow so that suicient oscillation strokes can occur at the grinding zone to generate an accurate contour. When the completed piece is carried below the grinding throat, it drops off the blade. The contour of the wheels is maintained by suitable dressing devices (not shown).

I claim:

l. In a machine for generating a curved surface on a round work-piece, a grinding wheel and a regulating wheel spaced apart to form a grinding throat, a thrust plate extending along one side of the grinding throat, a movable feeding member at the other side of the grinding throat and having a Work supporting blade extending towards the thrust plate and adapted to travel through the throat peripherally of one of the wheels, and means providing for a relative movement of oscillation around an axis, between the grinding wheel on the one hand and the regulating wheel, feed member and thrust plate on the other hand; substantially as described.

2. In a machine for generating curved surfaces on round work, a grinding wheel and a regulating Wheel spaced apart to form a grinding throat, the peripheries of the Wheels being contoured to conform to opposite sides of the work, a feeding Wheel alongside of the regulating wheel and having a plurality of worlf` supporting blades projecting over the periphery of the regulating wheel, each blade having a contoured surface to conform to the work, a thrust plate extending along one side of the grinding throat to guide the ends of the work, means for slowly rotating the feeding wheel around an axis to traverse the work supporting blades through the grinding throat, and means operating during the travel of the blades to provide for oscillation around another axis of the regulating wheel, blades and thrust plate as a unit; substantially as described.

3. In a machine of the character described, a grinding wheel mounted to rotate on a fixed axis, a bed mounted to oscillate around an axis in the plane of the grinding Wheel, a regulating wheel mounted on the oscillating bed and having its periphery opposed to that of the grinding wheel to form a grinding throat, a thrust plate mounted on the oscillating bed and closing one side of the grinding throat, a feeding member mounted on the oscillating bed and having a thrust plate closing the other side of the grinding throat, work supporting blades projecting into the throat from the feeding member, and means for rotating the feeding member around an axis to traverse the blades slowly through the throat while the bed and the parts supported thereby are oscillated around the bed axis; substantially as described.

4. In a machine of the character described, a grinding wheel and a regulating wheel spaced apart to form a grinding throat, a feeding wheel alongside of the regulating wheel and having its periphery notched, a thrust plate secured to the feeding wheel and having its periphery notched, and work supporting blades secured in the notches and projecting laterally over the periphery of the regulating wheel; substantially as described.

5. In a machine of the character described, a grinding wheel and a regulating Wheel having their peripheries spaced apart to form a grinding throat, a feeding Wheel alongside of the regulating Wheel, a thrust plate secured to the feeding wheel and having its periphery notched, Work supporting blades secured to the feeding Wheel and projecting through the notches of the thrust plate into the grinding throat; substantially as 5 described.

RAYMOND H. CRAMER.