US1676620A - Grinding apparatus - Google Patents

Description

July 16, 1928., 11,676,62Q

c. H. NORTON GRINDING, APPARATUS Filed Jan. 2, 1923 I l9 Q 20 3M1,

Char/es H. N0r7bn- Patented July 110, i928.

re iant Parent curios.

UNKWED TATES CHARLES H. NORTON, OF PLAINVILLE, CONNECTICUT, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO CINCINNATI GRINDERS INCORPORATED, 011 CINCINNATI, OHIO, A COR- PORATION OF OHIO.

GRINDING APPARATUS.

Application filed January 2, 1923. Serial'No. 610,093.

lllyjnvention relates to the art of grinding and more particularly to grinding apparatus for grinding small cylindrical objects and removing considerable stock therefrom at a single pass.

The ordinary commercial method of grinding cylindrical work involves support ing the work on centers or in a chuck and reciprocating the work along its axial line across the peripheral face of a rapidly rotating grinding wheel and progressively advancing or feeding the wheel into the work as the grinding operation proceeds. The reduction in diameter of the work' ata single pass across the wheel is a function of the grain depth of cut and depends upon the size of the grain,' the openness of the wheel structure and the ability. of the wheel to 7 force the grain into the work. Hence the depth of cutis relatively small. In grinding small cylindrical bodies without'the aid of centers, it has notbeen readily feasible, heretofore, to rough and finish grind the article at a single pass or to take a out which is deeper than the grain depth.

One of the objects of this invention is to provide a thoroughly practical grinding apparatus whereby, even though the work pieces are of such character that they cannot be supported upon centers or in a chuck, a relatively heavy cut may be taken at a single pass and hence a relatively large amount of material removed, in a thoroughly eflicient and dependable manner. Another object is to provide an apparatus of the above-mentioned character inwhi'clr a high degree of accuracy' of grinding may be achieved even though the depth of cut is relatively large. Another object is to provide a grinding apparatus of the above-mentionedtype in which a high degree of both accuracy and'finish'of grinding may beachieved and to provide a grinding apparatus capable of giving such heavy grinding surfacethroughout long continued periods of operation.

Another object is to provide a grinding ap paratus in which uniformity of wear of the grinding wheel may be dcpendablyachieved' even though the grinding wheel is called upon to perform relatively heavy duty throughout relatively long periods of opera' tion. Another object is to provide grinding apparatus of the above-mentioned character in which relatively small cylindrical work pieces may be rapidly and'in succession given substantial reduction in diameter and reduced to not only a high degree of accuracy of roundness butalso given a high degree of finish. Other objects will be in part obvious or in part pointed out hereinafter.

The invent-ion accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will till be exemplified in the structure tobe hereinafter described and the scope of the applicaa simplified form of grinding machine adapted to carry out my method;

2 is a fragmentary front elevation havmg the work rotating wheel and its adusting slides removed to show more clear-, ly the relation between the work support, the pushing mechanism and the grinding wheel;

Fig. 3 is a diagrammatic plan View of ant form of pushing mechanism which may be employed to I move the work during the grinding action and Figs. 4, 5 and 6 show different formsof work support, which may be employed in my apparatus. j

In accordance with my invention, I propose to grind a rotating cylindrical body on a tapered surface progressively from one end of the work to the other, in such a man ner that the work is solidly backed up and i rotated during grinding action thereon and quickly reduced in size at a single pass from the diameter of the larger end of the taper to that of the smaller end. To grind small objects without the aid of supporting centers, I employ two opposed abrasive wheels, one for grinding the work and the other for controlling its rotation. -The wheel faces are arranged at such angles that a desired taper may be ground depending upon the ultimate reduction insize to be accomplished at a single pass. 'The work piece .to be ground is passed along a work rest intermediate of the two wheels and is held inoperative re lation to the two Wheels by the work rest;

' the work rest and the two wheels areso arranged that they present three lines of contact to the workpiece, these three lines of contact forming elements of afrustrumof a cone'whose axis coincides with the axis of the work piece whichfis moved alongthe work rest in. a' direction toward the narrower end of the grinding throat formed by thevtwo" wheels and the work rest. For this purpose. I preferably employ cylindrical wheels and I arrange them so that their peripheral faces are f exposed for-contact with the work, wThese cylindrical wheels are preferably mounted with their-axes at anangle to each other,"-and the work is caused to move along a line which bisects this angle. If it is desired to employ wheels mounted on parallel axes, their faces may accordingly be beveled to give the desired taper, this operation being performed by any suitable mechanism knownin the art.

If the work were passed axially parallel H to the grinding wheel axis as has heretofore been customary, then one-peripheral corner of the wheel would be obliged to do the ma' jor portion of the grinding and the re mainder of the wheel would not be used to its full capacity. Such a wheel would, therefore, wear rapidly at its peripheral corner and would rapidly be used up and wasted, due largely to the truingoperations, since it is frequently necessary to pass a diamond across the face of the-wheel to turn down and thuseliminate the very rounded cornerwhich has been giving the ma n grinding service. In accordance with my method, the

whole wheel face is uniformly brought into grinding action, and such disadvantages as those just pointed outavoided. I thus achieve high efficiency of grinding.

Referring to Figs. 1, 2 and 3 of the drawings I have there illustrated the certain preferred features of one form of 'a grinding machine, which'may be'employed for carrying outmy method automatically. I As there shown, I mount a cylindrical grinding wheel 10 on suitable bearings carried by the upper member 11 of'the wheel slide 12 which is adapted to slide'on the usual V and' fiatways' on the machine base-13. The'wheel slide 12.

- slide 12.

The wheel slide may be fed forward by a suitable hand controlled nut and screw mechanism, such as shown in Fig. 1. This feed mechanism comprises a half nut 16 depending from the wheel slide 12 and adapted to engage the screw 17, which is rotatably mounted in the basev of the machine. This screw is operated by means of the hand wheel 18 which turns the'pinion 19, meshing with the gear 20 on the screw shaft.

The work is suitably supported on a re- 'movable work support 21, which may be adjustably positioned on an upright 22' projecting from the "machine base and is arranged to hold the work in grinding contact with the Wheel 10. This support 21 is proyided with a suitable surface preferably adapted to hold the work against 1e peripheryof the grinding wheel, preferably below a horizontal line passing through the wheel axis,.so that the wheel will'gi've a downward thrust and ai'd'to keep the work iniposition on its rest. The wheel periphery is, for this.

purpose, rotateddownwardly toward the work, as indicated b the arrow in Fig. 1.

For rotating an suitably mounted on asecond slide 24 which .is adjustable vertically by the usual handoperated nut and screw mechanism 25 Both the grinding wheel and the work rotating "wheel may be rotated by suitable mechanism,

which is diagrammatically illustrated as taking the form of pulleys and.belts deriving-power from suitable overhead shafting.

'Toi'adjustlthe Wor Wheel toward and-from the work,:I mount the vertical slidel'24bn a horizontal cross; slide 27 operated by the usual hand operated nut and screw mechanism 28. The slide 27 is in turn carried; by a turntable 29 mounted to swivel upon the-boss 30 on the part 22 of the base 13, thus permitting the'work-rotating wheel to-"be turned about vavertical axis, depending upon the taper to be ground.'- To permit locking the turntable 29 in adjusted position, I provide cap screws 31 passing through arcuate slots in the turntable, and screw-threaded into the basel The workrotating wheel is driven in the .directionrof the arrow. -T he grinding wheel 10 is ordinarily rotated rapidly to grind the work and the wheel 23 'tionthereof.

The work may be moved axially relative backing up the work during the grinding action thereon, I pro- --vide a second rotatable abrasive Wheel 23,

slowly to control the rotato the wheels by hand or by suitable means.

I achieve, however, certain distinct advantages by employing a mechanismja pre-' ferred form of which I will now describe. As shown in Figs. 2 and 3, I may provide a cam controlled pusher mechanism comprising a plunger 32 mounted for reciprocation in the sleeve 33 and having a pin 34 projecti lng laterally through a slotin the sleeve for H engagement with the cam member 35, which is eccentrically. mounted on a pivot 36 and suitably rotated by a pulley 37. The cam 35 is preferably of the s ape illustrated, hava frusto-conical surface.

ing a portion of its surface adapted to move the pusher uniformly forward while feeding the work and a further portion to return the pusher quickly to the starting position. A spring 38 engages the end of the sleeve 33 and an enlarged head 39 on the pin 3%, and serves to retract the plunger when permitted by the cam.

As shown in Figs. 1, 2 and 3, the wheel axes are preferably arranged at an angle to each other, but preferably in the same horizontal plane. Hence, if the wheels are cylindrical in shape and if the work is moved axially in a horizontal plane and along a linebisecting the angle made by the wheel axes, the work will necessarily be ground on In order to supportthe work properly during the grinding action, I may provide various work supports, such as shown in Figs. 4, 5 and 6. Of these supports,-I prefer that illustrated in Figs 4, in which the block 21 is shown as provided with a concavepartial frusto-conical surface 40, which fits the work in size and shape when the work is in full grinding contact with the wheels. If desired, I may employ a V-shaped rest, such as shown in Fig. 5, in which the two plane surfaces'l and .42 will'properly contact with the tapered work. The rest shown in Fig. 6 is provided merely with a sloping plane surface 43, which provides a single line contact with the work, the surface 43 sloping (as will be clear from Figure 2) in a direction axially of the work and to an extent depend ing upon thedegree of taper being ground.

Since the work is reduced materially in size at a single pass, I preferably provide the work support with three supporting zones, the central one being as illustrated in Figs. 4c, 5 or 6. The Zone on the side of the entering work preferably has its supporting surface 44 formed as a concave, partial cylindrical surface of substantially the radius of the rough piece tobe ground, while the opposite end of the work rest has a similar partial cylindrical surface 45 whose radius conforms to that of the finished work.

In accordance with my invention, I pass a cylindrical body 50 axially in contact with the active faces of the two wheels which faces are so angularly disposed that, as the work is moved axially, it is rotated and solidly backed up by the work-rotating wheel 23 and ground on a tapered surface progressively from the forward end of the work to the rear by the grinding wheel 10, the full face of the latter uniforn'ily taking part in the grinding. If,as shown in Fig. 3, and as is desirable in the art of centerless grind ing, the wheel faces are as wide as the work is long, then the work, as it moves into or enters more and more the grinding zone, will be ground throughout an increasing area until it is in full operative contact with 51 in Fig.

the peripheral faces of the wheels. At this time, the work has a substantially fru'stoconical shape, as indicated by the numeral Thereafter, the work in passing beyond the grinding zone or out of the grinding throat will be again given a cylindricalsurface by the wheels and will issue as a smaller cylindrical body 53 of the desired size. Itis to be noted that every portion ofthe face of the grinding wheel '10 takes a like part in the grinding of the work while the latter is rotated and solidly backed up by the Work-rotating wheel 23, and thus a uniform distribution of grinding and uniform wear throughout the face of the grinding wheel areachieved.

It will thus be seen that there has been as well as manythoroughly practical ad-' vantages are successfully achieved. It Will be noted that the effective cut of material removed from the work piece is not restrict. ed to or hn'ntedby the distance. to which.

an abrasive grain projects from the surface of the grinding wheel, I101 1S it restricted by such factors as have been hereinbefore noted; on the contrary, it will be seen that' the effective out which the apparatus is capable of making at a single pass may be rela tively heavy and actually is equivalentto the difference between the diameter at the larger end of the frusto-conical grinding throat and the diameter of the grinding throat at the smaller end of the latter. This difference may be widely varied, as will be clear from the foregoing, and" likewise the depth of cut achieved at a single pass. Furthermore, the entire operative surface of the grinding wheel is uniformly brought into action so that the grinding wheel remains true for very great intervals of time and, moreover, the grinding wheel, due to the resultant uniformity of wear, need ,be but infrequently trued. In this latter connection, the action of thework-rotatingwheel 23 is backs up the work during the grinding action thereon by the grinding wheel, but also insures-the proper distribution of grinding action across theactive face of the grinding unique in that it not only rotates and solidly i wheel as the work piece enters the grinding I throat and also as the work piece leaves the grinding throat. It .will furthermore be seen that the apparatus iswell adapted to meet'the. varying conditions of hard practical use. A 1

As man poss ble embodiments may be made of tie above invention and as many changes might be made in'the embodiment above set forth, it isrto be understood that all matterhereinbefore set forth, or shown in the accompanying drawing is to be interpreted as illustrative and not in ajlimiting sense.v

scribed, in combination, a grinding throat adapted for simultaneous grinding and rotating action upon Work of round section and comprising three means, one of which means is. in the form of a grinding wheel adapted to be rotated at' a relatively high speed, another of said means being in the, form of a regulating wheel adapted to be rotated at a relatively low speed and in a direction to present 'an operative surface traveling in a direction opposite from that of the adjacent grinding wheel-surface and adapted thereby to control the rotation of the work, and the third of which means includes a member for holding work of round section in operative relation to said'two wheels, each of said means being shaped-to present a line of contact to work of round section and said three means being related one to the other so that the lines .of contact presented thereby to the work form elements of a frustrum of a cone; and means for moving awork piece into and through said grinding throat and in a direction from the larger end of said grinding throat to the smaller end thereof, thereby progressively to grind a frusto-e'onicalsurface from one end of the work to the other and to reduce the work piece to a diameter equal to that of the smallerend of the frustrum.

2. In apparatus of the character described, in combination, a grinding throat adapted for simultaneous grinding and rotating action upon work of round section and comprising three means, one of which means is in the form of a grinding wheel adapted to be rotated at a relatively high speed, another of said means being in the form of a regulating wheel adapted to be rotated at a relatively low speed and in a direction to present an operative surface traveling in a direction opposite from that of the adjacent grinding wheel surface and adapted thereby to control the rotation of the work, and the third of which means includes a member for holding work of round section in operative relation to said two wheels, each of said means being shaped to present aline of contact to work of round section and said three means being related one to theother so that t-he lines of contact presented thereby to the work form elements of a frustriun of a cone; means for moving a work piece into and through said grinding throat and in a direction from the larger end of said grinding throat to the smaller end thereof, thereby progressively to grind a frusto-conical surface fromsone end of the" work to the otherl and to reduce the work piece to a diameter equal to that of the smaller end of the frustrum; and means for guiding the reduced finished work piece out of the grinding throat and adapted to maintain the axis of the work piece as it emerges from the grinding throat substantially coincident with the said frustrum of the cone.

traveling in a direction opposite from that of the adjacent grinding wheel surface and adapted thereby to control the rotation of the work, and the third of which means includes a member for holding work of round section in operative relation to said two wheels, each of said means being shaped to present a line of contact to work of round .section and said three means being related one to the other so. that the lines of contact presented thereby to the work form elements of a frustrum of a cone; means for moving a work piece into and'through said grinding throat and in a direction from the larger end of said grinding throat to the smaller end thereof, thereby progressively to grind a fr'usto-conical surface from one end of the work-to the other and to reduce the work piece to a diameter equal to that of the smaller end of the frustrum; and means for guiding the work piece to be ground into the grinding throat and adapted to maintain the axis of the entering work piece substantially coincident with the axis of the said frustrum of the cone.

4. In apparatus of the character. described, in combination, a grinding throat adapted for simultaneous grinding and rotating action upon work of round section and comprising three'means, one of which means is in the formof a grinding wheel adapted to be rotated at a relativelyv high speed, another of said' means being in the form of a regiilat-ingwheel'adapted to be rotated at a' relatively low speed and in a direction to present an operative surface traveling in a direction opposite from that of the adjacent grinding wheel surface and adapted thereby to control the rotation of the work, and the third of which means in-' eludes a' member ifor holding work of round section in operative relation to said two wheels, each of said means being shaped to tuated member adapted to be' moved in a dim rection toward the smaller end of the grinding throat and tomove into and through the latter a Work piece and adapted upon retrograde movement thereof to have positioned in front of it a' succeeding Work piece to be moved into ing throat. v

5. A grindingvmechanism including a grinding throat adapted for simultaneous grinding and rotating action upon Work of round section and comprising three means, one of which means is in the formof a grinding'wheel adapted to be rotated at a relatively high speed, another of said means being in the form of a regulating Wheel adapted to be rotated at a relatively low speed and in a direction to present an operative surface traveling in a direction opposite from that of the adjacent grinding Wheel surface and adapted thereby to control the rotation of the Work, and the third of which means includes a member for holding Work of round section 'in operative relation to said tWo Wheels, each of said means being shaped to present a line of contact to work of round section and said three means being related one to the other so that the and through the grindlines of-contact presented thereby to the work form elements of a frustrum of a cone; said mechanism being constructed and arranged to move a Work piecethrough said grinding throat in a direction from the larger end of'the latter toward the smaller end of the latter.

6. In apparatus of the character described, in combination, a grinding throat 29th day of adapted for simuitaneous grinding and rotating action upon Work of round section speed, another of said means being in the form of a regulating Wheel adapted to be rotatedvat a relatively low speed and in a direction to present an operative surface traveling in a direction opposite from that of the adjacent grinding Wheel surface and adapted thereby to control the rotation of the work, and the 'third of which means includes a member for holding Work of roundsection in operative relation to said two Wheels, each of said means being shaped to present a line of contact to Work of round section and said three means being related one to the other sothat the lines of contact presented thereby to the Work form elements of a frustrum of a cone, said members having portions extending beyond the the cone, the portion at the entry end of said grinding throat being displaced from th said axis by an amount substantially equivalent to the radius of the larger end of the frust-rum of the cone and the portion at the exit-end of said grinding throat being displaced from the said axis byan amount substantially equivalent to the radius of the smaller endof the said frustrum of the cone. Signed at Worcester, Massachusetts, this Dec. 1922.

CHARLES H. NORTON.

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