US2097783A

US2097783A - Grinding machine

Info

Publication number: US2097783A
Application number: US44204A
Authority: US
Inventors: Raymond A Cole
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1935-10-09
Filing date: 1935-10-09
Publication date: 1937-11-02
Anticipated expiration: 1954-11-02

Description

Nov. 2, 1937. R. A. COLE 2,097,783

GRINDING vMAGHINE Filed Oct. 9, 1935 2 Sheets-Sheet 2 00|000000000OOOCOOOOOIOIIOOOI HYMU/vu A. Em E /W 40% @M .WQWAFW' Gnomwu Patented Nov. 2, 1937 UNITED STATES l onnvnmo Maclmvr: o, Ramond A. Cole,.Worceatei-,' Mass., assignor to Norton Company, Worcester,

Mass., a corporation of Massachusetts Application October. 9, 1935, Serial No. 44,204

4Clnims.

The invention relates to grinding machines and with regard to its more specific features to a sizing mechanism therefor.

One object of the invention is to provide an electric sizing device of simple construction and dependable in operation. Another object of the invention is to provide 'a sizing device having no contact with a work piece. Another object of the-invention is to provide an' electric sizing device whose sensitivity is not affected by aroing. Other objects will be\in part obvious or in part pointed out hereinafter. A

The invention accordingly consists in the features of construction, "combinations of elements, and arrangements of parts as will be exemplied in the structure to be hereinafter described and the scope of the application of-.which will be indicated in the following claims. v

Inthe accompanying drawings, in which is shown one of various possible embodiments of the mechanical features of my invention;

Fig. l is a vertical transverse sectional view.'

showing the hydraulic actuating and control mechanism for the cross feed slide of a grinding machine, and illustrating also the calipering mechanism,

Fig. 2 is a fragmentary vertical sectional view, the section being taken on the line 2-2 of Fig. l, 1 Fig. 3 is-`an electrical and optical diagram.

I provide a grinding machine including a. Y machine base i6 having theo'usual ways Ii, i2 for the support of a work table I3 upon which is supported a headstock and a tailstock, not shown, for the support and rotation of a workpiece I4 which 'is to be` exteriorly ground. 'I'he usual mechanism foi' traversing the work piece by longitudinal reciprocation may be provided, but

,so' far as certain features of the invention are concerned thegrinding may be by the so-called ,plunge-cut" method, in which the grinding wheel advances relative to the work piece without relative traverse thereof, or with only limited re ciprocation for the removal of grinding lines.

Mounted on the usual-cross feed slideway, not shown, is a cross slide -I5 of any usual or desired form having a wheel head I6 which journals in journals i1 the'spindle i3 of a 'grinding wheel i3. The wheel I3 may have a wheel guard 20 of any usual or desired construction.

Referring now to Figs. 2 and 3,'fastened to the inside of the machine base I6 underneath theA tableV i3 are a pair of brackets 2|, 2| supporting

journals

22, 22 for a `rock shaft 23 upon which is mounted optical apparatus generally indicated by the numeral 24. 'Ihis optical apparatus 36 and top plate 3l, the plates 21, 30 and 3| being integral with each other and with the ,web 28. Extending downwardly from the bottom of `the box 2.6 and integral therewith is a web 32having a journal 33 integral therewith, through 10 which journal 33V passes the rock shaft 23. 'I hus the optical apparatus 24 is supported yby the machine base, and it maybe adjusted in position parallel to the ways il ,and i 2 and by moving the journal33 along the shaft 23, and `when a l5 desired position of adjustment is attained the journal 33 is locked upon the rock shaft 23 as by means of a set screw 34, there being a hole 35 in the machine frame for Aaccess to the optical apparatus. In so much as the shaft 23 may always turn in the `journals 22, the optical apparatus 24 may be swung back and forth and adjusted angularly'around the axis of the shaft 23. Extending downwardly from theK journal 33 and preferably tegral therewith is an arm 36 4which is connec ed by means of a .spring 39 to the machine base i6, the spring 39 serving to urge the entire optical apparatus 24 in a clockwise direction, Fig. 1. A screw 40 having a hand wheel 4i for convenient adjustment from 0 the front of the machine constitutes an adjustable stop for the arm 38,' by means of which the position ofv the optical apparatus may be delicately adjusted. For quick forward movement of the optical apparatus, however, it may be 35 swung to the front of the machine by hand, and to hold it' there while changing *work pieces any desired latch or the like may be provided, such as the' hook 42 andeye 43.

In the box 26 I provide` a pair of electric light to` bulbs `4t -which` may be ofthe point of light type or of the ribbon filament type in order to produce a beam having as little stray ,li ht as possible within practical limits. In the box-26 is also a mirror 46- set at anangle approxi- 45 mately to the axes of the p i tubes 25.

In each tube 25 is a pair of 'con a n "

lenses

41,

,48, and in plate 21l located/inl oriil ,es 43 are concave lenses 50. `The f r 46, lenses 41 `and 48, and lenses 50 may be made adjustable injthe 50 usual way, not herein vshown in detail as constructions for lens adjustments and the like are well understood. Attached to the web 26 and extending from' it on either side is a pair ofsup4 ports 5I for convex lenses 52. Extending for- '55 wardly from the plate 30 and suitably insulated yare thecdnventional four-hole sockets 53 for the support of photoelectric cells 54 (only two of the .prongs being electrically connected).

. the filaments of the lights 45, are reflected by the a hand wheel 68. v The brackets 2|have slots 69' mirror'46 through the two pairs of

condensing lenses

41 and 48, and the converging beams are spread to some extent by the lenses 50. However, between the lenses 50 and 52 I desire that the beams shall become crossing beams 51 and 58 with foci F in the horizontal plane of. the axis of the work piece I4. From the foci F the beams spread and are by the lenses 52 transformed into

crossing beams

59 and 60 whose cross sectional 'area is approximately equal to that of the cathodes 6| of the photoelectric cells 54 at that point.

The axes of the beams 55, 51 and 59 are. parallel to each other and to the axes of the

beams

56, 58 and 60. But I desire that the work piece I4 shall uncover them successively. The interval between uncovering of the two beams is a matter of a few ten-thousandths of an inch, for example fteen ten-thousandths of an inch (.0015"), and this may be achieved in many ways. For example, and referring to the lower part of Fig. 2, the left-hand bracket 2| may have a portion 65 depending therefrom which includes a boss 66 through which passes a screw 61 controlled by and are held to the frame I by bolts 10 passing through the slots 69, and by reason of the direction of elongation of the slot 69 the brackets may be adjusted in a horizontal direction, and preferably the shaft 23 is a shouldered shaft so that all play can be taken out of the parts when vthe brackets 2| are austed and fastened in position. 'I'he left-hand end of the shaft 23 may be moved to'the front of the machine by an amount suicient to make the difference, in ten-thousandths of an inch, between uncovering of the beams 51 and 58, by turning the hand wheel 68, which will spring the left-hand bracket 2| outwardly to a slight extent, or if this is not enough the lower bolts` may be slightly loosened.

Various expedients may beadopted to form a very narrow focus F for each beam. With the system of lenses shown and described, if the filament of each bulb 45 were a geometrical point the foci F would also be geometrical points except for color aberration. But a color lter may be used in connection with theapparatus for more accurate results, and this color iilter may be placed under the lowermost lenses 41. .The focus F of 'each beam,`however, is still an image of the lamp lament. Point-of-light electric bulbs are now available, in which the luminous part is very small. I lprefer to use such, but a ribbon filament light has 4a relatively small light source. However, the use of diaphragms, while they *diminish the intensity of the light, maybe resorted to. A feature.of the electrical apparatus about to be described is that, in conjunc-A tion with a photoelectric cell, it is quite sensitive and responds to a certain quantum of light, which while not absolute in the true sense is nevertheless unvarying within practical limits of a few ten-thousandths of an inch in the size of the work piece, when used in connection with the apparatus of the invention.

In the preferred embodiment of the invention actuation of one photoelectric cell 54 causes crossl pressure fluid is moving feed movement between grinding wheel l0 and` work piece I4 to cease, while actuation of the other photoelectric cell 54 causes the cross slide I5 to retreat carrying the grinding wheel I0 dednitely away from the work piece. Grinding between the first indication or electrical actuation and the final coming to size takes place owing to the pressures set up in the machine parts and such grinding, already known in connection with manually operated. machines, has been termed sparking out. The invention is shown embodied in an external cylindrical grinding machine, and the first actuation in some cases may be a slowing down of the cross feed rather than an actual discontinuance of ail movement. The mechanism of the present invention may be adjusted so as-to bring the cross slide I5 to a stop at the first photoelectric actuation, or it may be adjusted so as to decrease the rate of cross feed rather than to stop it altogether. v

In the preferred embodiment of the invention I use av hydraulic cross feeding mechanism which may be readily controlled by solenoids actuated by the photoelectric cells 54. Referring again to Fig. 1', depending from the cross slide I5 is a bracket |05 to which is attached a piston rod |06 having a piston |01 located in a cylinder |08. A slide valve |09 has reduced diameter portions ||0, III and ||2, which are separated by full diameter portions fitting a valve bore H3. A port ||4 connects to the right-hand side of the cylinder |08 while a port ||5 connects to the left-hand side thereof. A passage ||6 connects the port ||4 with a valve port ||6, and a passage ||1 connects the port ||5 with the valve port H9. As shown in Fig. l, the ports ||6 and I9 are symmetrically located in the bore |I3, one being slightly to the right of the center portion thereof, and the other an equal distance to the left.

The bore ||3`also has ports |20, |2| and |22,

ythe former being a duid entrance port and con- `The valve |24 is connected by piping |26 to the piping |25 as clearly illustrated.

With the slide valve in the position shown in full lines in Fig. 1, 'flnid underpressureis admitted from the piping |23 through the' port |2| and past the reduced portion to the port ||8 and the iiuid passes through passage ||6 to the port ||4 which is. at the right-hand end of the cylinder |05 and therefore the fluid will urge the piston |01 tothe left thus to move the cross slide |2 and carry the grinding wheel |5 towards and to reduce the diameter of the work piece The parts are shown at the commencement of this operation in Fig. 1. While the piston |01 to the left, nuid 1s being exhausted from the left-hand i0 side of the cylinder |08 and it flows `outwardly by way of port II5, passage II1, and port II! past reduced diameter portion ||2 and through piping |28 to valve |24 and thence by way of pipe m imcpipe |25 which connects with the l5 "23,037,783 fluid' sump or source of supply. When the valve I I9 and by passage ||1 to p( [H6 and thus into thev mrt-hand side of the! 'c vunder los. This causes movement of the piston |01 to the right thus carrying the grinding wheel I6 away from the work piece, and the fluid is forced out of the right-hand sideA of the cylinder |08, through port II4, passage. ||6, through port |-|3, past reduced diameter portion ||0 to port |22 and by way of piping |25 to the sump.

It will be noted 4from the foregoingdescription that when the grinding wheel is traveling inwardly or to the left the exhaust fluid is passing through the valve |24, but whenthe grinding wheel is moving outwardly or to the right the exhaust fluid does not pass through the valve |24. The valve |24 is an adjustable metering valve and may be set to stop position; thus it controls the advance of the grinding wheel and procures a slow feed thereof and it is capable of being moved to -a position to reduce thel feed or to stop it altogether. N

las

According to the preferred embodiment of the present invention the machine has three main parts to a cycle of operation. `There is first `the infeed of the grinding wheel when the solenoia |43 is deene'rgized and the valve m 1s at its adjusted open or" widest open position. Then follows the grinding cycle while the solenoid |43 is energized, the' piston |33 being to the right and either restricting, the flow of fluid through the valve 24 more than previously or else cutting it oifaltogether. Thirdly, there is the return of the grinding wheel to a retracted position which is not controlled by the valve |24'at all.

-' The change from the first to the second phase of the grinding cycle is determined by one indi- .cation from the sizing apparatus and the change. from the second to the third phase of the cycle is determined by a second indication of the sizing apparatus. Asso far described the righthand -photoelectric cell 54 (Fig. 2). sets in motion the change from the first to the second phase and the left-hand photoelectric cell 34 sets in motion the change from the second to the third phase. Thenchange from the hthird to the rst phase might be edected in any manner but so the solenoids and the operator has ample time to shift the rod |33.

It should be noted that "either of the photolelectric .cells 54 'may be-selected forinitiating either change, as this is simply a matter of connection of two pairs of final circuit wires. Furthermore, the sizing apparatus may be adjusted so that the change from therst phasmto the.

second phase occurs at the end of the movement which brings the grinding wheel against the work piece, or the change may beeifected when the work piece is nearly to' size so that the'nal cuts will be in the nature o f a ne grinding operation. I prefer to adjust the valve |24 so that no advance of the grinding wheel will take place after thesolenoid |43 is energized, the further reduction of the work piece" being due to the strain or spring in the machine parts and the nal cuts being what have been described yas dying out cuts, or simply sparking out. The

true cylindrical ne-nish and -accurate work.

'I'he calipering mechanism of the invention may l be readily adjusted so thatV the difference between actuations of the two photoelectric cells is within the range of the amount of size reduction effected by a dying-out cut.

Referring now to Fig. 3, the right-hand photoelectric cell 34 is associated with amplifying and relay apparatus to energize the .solenoid |43, while the left-hand photoelectric cell 54 is associated with identical apparatus to energize the solenoid |32. v Any` amplifying and/or relayrapparatus 'may be used,` and direct or alternating current may be employed in any of the circuits, f

as my invention is not confined to any particular electrical arrangement. For Dill'pvses of illustration, however, I have disclosed in Fig. 3 a set ofcircuits which may be employed. f

Pendulum contactors |93 and |93a are adapted to connect terminals |90|92 on the one hand and |90a|92a on the other hand. These pendulum contactors are arranged to be operated by long arms |84 and |94a of armatures |95 A and |95a actuated by the coils |85 and |85a.

Energization of the relay coils |9| andy |9|a respectively, even momentary energization thereof, causes the closing of knife switches |91 and |91a. These are double knife switches and one set of terminals thereof is connected by shunt leads to the 1l0'volt A. C. wires |56, |51 and |56a, |51a, respectively, while the other terminals of these knife' switches |91 and |91a connect to lines 200 and 200a which respectively lead to the solenoids |43 and |32.

The pendulum contactors |93 and |93a may be of spring steel so that normally they lie in the position shown in Fig. 3 but a slight force will throw them into contacting position. The photoelectric cell cathodes 6| and 6| are preferably sensitive caesium plated cathodes and a certain definite amount of light on either of them will cause enough current to flow in either of the relay coils |85 and |85a to close the cir cuitby contactor |93 and |93a. By producing Anarrow beams of light 51 and 58 and providing sensitive double relay apparatus one element of which is a current measuring relay, I am enabled accurately to size the work.

In order to set up the machine, a work piece I4 ground to the desired size by 'means of hand gauges is placed in the machine centers and the optical apparatus 24 is then moved towards the work piece to the full line position shown in Fig. 1. In this iigure the apparatus is shown moved to the right as far as itwill go and the smallest size of work piece |4 -which can be gauged by a particular sizing apparatus according to the invention will 'cut oil' the beams of light. Both lamps 45 are lighted and the switches are closed. The hand; wheel 4| should now be turned to the right and first the solenoid |43 will actuate and later the solenoid |32. As the solenoid |32 actuates the adjustment is'nished. At this time the hydraulic motor is not operat- -lng at all.

'A scale may be provided in connection with the hand wheel 68 and if the interval between actuations of the solenoids was not satisfactory, the hand wheel 68 may be turned and the trial gauging repeated. After this is done the trial work piece I4 is removed, and an oversizedwork piece. is placed between the centers, and' the switches again closed and the rod |30. is drawn toward the front of the machine. Many other manners of adjusting the machine and many varied cycles of operation may be adopted.

In this embodiment of the invention the optical apparatus 24 is shown attached to the machine base and it extends through a slot 20| in the table I3. This locates the sizing apparatus always opposite the grinding wheel. The slot 20| may be as long as the stroke of relative traverse between the wheel and the work piece.

In order to eliminate a light intercepting lm of water upon the work piece I provide a wiper 202 which may be made of rubber or nbre or any other substance that will conform to the work pieceand remove the major part of any water or other matter adhering thereto. It will be observed that the sizing apparatus of this invention leaves no scratch marks upon the work piece and may be quickly adjusted for different sizes of work pieces.

It will thus be seen that there has been provided by this invention an apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As various possible embodiments might be made of the mechanical features of the above invention and as many changes might be made in the embodiment above -set forth, it is to be understood that all matterv l. In an external cylindrical grinding machina,

means kfor holding and rotating a work piece to be ground, a grinding wheel, means for procuring a cutting advance between said means and said grinding. wheel, a support for optical apparatus including a long tube, lenses in the tube, a light source at one end of the tube, a photoelectric cell xed with relation to the support and located with respect to the light source and the lenses so that it. will conditionally receive light from the source via the lenses, means for altering the cutting advance of the work piece, and amplifying means responsive to the photoelectric cell operating th means for altering the cutting advance, the support y means for holding and rotating the work piece. that an oversized work piece intercepts some of the rays from the light source and at a particular size ofthe work piece the photoelectric cell is energized.

2. In apparatus as claimed in claim l, the comv bination with the parts and features therein specifled of adjustment means to move the support to being so located with relation to the'l adapt the apparatus for dierent sizes of work?- additional photoelectric cell, constructed and operating as delined in claim l. whereby to effect dual control of the cutting advance to change from a' coarse grinding operation to a ne grinding operation when one photoelectric cell is actuated and to cause cessation of grinding when the other photoelectric cell is actuated.

4. In apparatus as claimed in claim l, the

combination with the parts and features therein energized.

RAYMOND A. COLE.