US2590717A

US2590717A - Automatic gauge regulator for grinding and polishing machines

Info

Publication number: US2590717A
Application number: US210561A
Authority: US
Inventors: Wallace K Lowe
Original assignee: Crucible Steel Company of America
Current assignee: Crucible Steel Company of America
Priority date: 1951-02-12
Filing date: 1951-02-12
Publication date: 1952-03-25
Anticipated expiration: 1969-03-25

Description

March 25, 1952 w. K. LOWE AUTOMATIC GAUGE REGULATOR FOR GRINDING AND POLISHING MACHINES 6 Sheets-Sheet 1 Filed Feb. 12, 1951 'INVENTOR. WALLACE: K. Lovvz-z.

BY I I ATTORNEYS.

March 25, 1952 w. K. LOWE AUTOMATIC GAUGE REGULATOR ,F 0R. GRINDING AND POLISHING MACHINES V 6 Sheets-Sheet 2 Filed Feb. 12, 1951 INVENTOR. WALLACE K. Lowe.

WMEM ATTORNEYS March 1952 w. K. LOWE 2,590,717

AUTOMATIC GAUGE REGULATOR FOR GRINDING w AND POLISHING MACHINES Filed Feb. 12, 1951 e Sheets-Sheet 3 IN VEN TOR.

BY WALL-ACE. K.LOWE

wcmg, PM

ATTORNEY-5.

Match 25; 1952 DING w. K. LOWE AUTOMATIC GAUGE REGULATOR. .FQR GRIN AND POLISHING MACHINES I 6 Sheets-Sheet 4 Filed Feb. 12 1951 ATTORNEYS.

March 25, 1952 w. K. LOWE AUTOMATIC GAUGE REGULATOR FOR GRINDING AND POLISHING MACHINES 6 Sheets-Sheet 5 Filed Feb. 12, 1951 Nov INVENTOR.

WALLACE K. LOWE ATTOR/VEVS Mama,

March 25, 1952 w; K.'LO,WE 2,590,717

. AUTOMATIC GAUGE REGULATOR FOR GRINDING AND POLISHING MACHINES 6. Sheets-Sheet 6 Filed Feb. 12, 1951 EN pmN L? M @RHHH g T wmm [III]! nQN m Wu A TTORNEVS.

Patented Mar. 25, 1952 AUTOMATIC GAUGE REGULATOR FOR GRINDING AND POLISHING MACHINES Wallace K. Lowe, Syracuse, N. Y., assignor to Crucible Steel Company of America, New York, N. Y., a corporation of New Jersey Application February 12, 1951, Serial No. 210,561

12 Claims. 1

This invention pertains to gauge adjusting and automatic gauge regulating apparatus for grinding and polishing machines, and the like, which apparatus is arranged to provide for either manual or automatic adjustment and regulation of the gauge or thickness of the stock being ground or polished.

Although the invention is applicable to grinding and polishing machines in general, in which elongated stock is surface ground or polished by feeding the same past the one or more motor driven abrading elements, it is primarily intended for use in conjunction with centerless grinding and polishingmachines, particularly of the type described in my copending application Serial No. 199,410, filed December 6, 19 0, of which this application is a' continuation-in-part.

The invention comprises, in its essentials, a reversibly energizable screw-down motor for adjusting the motor driven abrading element toward and away from the stock surface to be ground or polished. This screw-down motor may be reversibly energized, either manually by means of push-button switches, or automatically by means of a regulator relay having a pair of magnetically coupled and opposed energizing coils, for actuating and controllably positioning, a pivotally mounted contact arm, which is deflectable from a median or neutral position, between the oppositely disposed fixed contacts, respectively, to energize the screw-down motor in one direction of rotation or the reverse.

The abrading element motor or motors is or are energized over a power supply circuit to which the magnetically opposed relay coils are current and voltage coupled respectively, over a pair of coupling circuits individual thereto. The current coupling circuit contains a rheostat for adjusting the relay contact arm to its neutral position, midway between its fixed contacts, for any given load current supplied to the abradingelement motor or motors, during the grinding operation. This rheostat is of the rotary type, the rotary arm of which is mounted on the shaft of a reversibledrive, rheostat control motor.

The rheostat control motor may be energized in one direction of rotation or the reverse, either manually by means of push-button switches, or automatically by means of a second regulator relay, similar to that which controls the screwdown motor, in that it is provided with a pair of magnetically coupled and opposed energizing coils, controlling a movable contact arm which pivots between oppositely disposed fixed contacts, wired, respectively, to energize the rheostat motor in opposite directions of rotation. This rheostat control relay is in turn controlled by a gauging element, which latter continuously gauges the stock being ground, and, in such manner, that as 5 long as the stock is being ground to the preselected gauge for which the regulator is set, the contact arm-of the rheostat control relay will remain in its neutral position, midway between its fixed contacts, but will respond to variations in the measured gauge, to deflect its contact arm in one direction or the reverse against the corresponding fixed contacts, in turn to so adjust the rheostat as correspondingly to actuate the screw-down motor control relay. The screw-down motor is thus energized in such direction of rotation and to the extent required, to restore the grinding to the preselected gauge. A switch actuated relay circuit is provided to arrange the gauge regulator for either manual or automatic control. 0 In operation, the regulator is initially arranged for manual adjustment, and the grinding or polishing machine is started up in conventional fashion, to feed the elongated stock past the abrading element, the motor driving the latter being also switched on. The screw-down motor is thereupon adjusted by means of the push-button contacts until the abrading element is grinding the stock to the desired or preselected gauge,

as determined, for example, by manual gauging.

Thereupon the rheostat is adjusted by appropriate push-button actuation of its control motor, until the contact arm of the screw-down motor control relay is positioned at neutral, i. e., midway between its fixed contacts. The system as thus adjusted is now ready for automatic regulation. and is cut over to automatic control, by means of the above mentioned switch actuated relay circuit provided for this purpose.

' With the gauge regulator thus operating under automatic control, the contact arms of the screw down motor and rheostat control relays will remain in their neutral positions as long as the stock is being ground to the preselected gauge. Should, however, the gauge increase or decrease with respect to the preselected value, the gauging element will actuate the rheostat control relay contact arm against the appropriate fixed contact for compensatively adjusting the rheostat, the adjustment of which will correspondingly actuate the screw-down motor or control relay, in turn, compensatively to energize the screw-down motor until the preselected gauge is restored.

' In addition to the basic components of the regulator circuit above described, it also embodies various other refinements as will be'ex- 3 plained below in the detailed description having reference to the accompanying drawings, wherein the regulator is described as applied to a centerless grinder of the type covered by the aforesaid copending application.

In the drawings:

Figure l is a side elevation of the centerless grinder to which the present invention is applied by way of illustrative example, but without limitation thereto; while Figure 2 is a section thereof taken at 22 of Fig. 1. a

Figure 3 is an end View, partly in section and with parts broken away, of one of the two grinding heads of the Fig. 1 construction; whileFi'g ure 4 is a side elevation, partly in section and with parts broken away, of this same grinding head. Figures 5 and 6 are sectional 'viewsthere of at 55 and 6-B respectively of Fig. 3, .while Figure 7 is a further section at 11 of Fig. 6.

Figure 8 is a circuit diagram of the gauge re ulator of the present invention as applied to the centerless grinder of Figs. 1-? inc.

Referring to Fig. 1, the centerless grinder to which the, invention is applied comprisesin general, a feed and straightening unit 29, a grinding and/or polishing unit 2|, a c ontrol unit 22, and a reeling or coiling unit 23, the grinder being adapted for grinding long lengths of rod or wire stock such as is conveniently handled in reel o r coil form.

To this end an unwinding reel or frame is provided at 24 for reception of a coil of stock to be ground, and from which it is unwound and fed into the apparatus. The wire stock is indicated at 25 and is directed first to a pinch roll unit indicated generally at 26 and which includes a pair of peripherally grooved rolls 2'! and 28 between which the wire stock passes and which feeds the stock into the wire straightening unit 29. One or both of said pinch rolls preferably are power driven by a motor 39 through the intermediary of a reduction gear 3|, the latter being connected to said rolls as by a sprocket chain 32.

The grinding and polishing unit 2| comprises a. main supporting shaft 33 which is journaled for rotation in suitable bearings 34 and 3 5. Shaft 33 is rotated by an electric motor 36, Fig. 2, which is operatively connected thereto by means of a worm and wheel reduction unit, 31 and by a sprocket chain 38 which engages suitable sprocket wheels 39 and 40 respectively secured to the'shaft'33 and to an output shaft of said reduction unit 31.

Secured to opposite extremities of shaft 33 are grinding

heads

41 and 42 which may be respectively employed for rough and finish" grinds upon the stock 25. The-grinding heads 4| and 42 are each completely enclosed by .

protective housings

43 and 44, respectively.

The motor 36 is mounted upon a main pedestal 45 which in turn supports a journal pedestal 46 upon which the

journals

34 and 35 are mounted.

Referring now to Figs. 3, 4 and 5, the main supporting shaft 33 rests in a suitable sleeve bearing as of Babbitt metal 351;, the latter comprising a part of said bearing 35. At the right: hand extremity of the main supporting shaft 33 (Fig.4) the grinding head 4| is located. This grinding head includes disc-like supporting head 41 which is rigidly secured to the shaft 33 for rotation therewith. The main supporting shaft 33 has formed therein an axial passage 3309 through which the wire stock 25 is fed. As

shown in Fig. 4, the wire stock is directed toward the center of the supporting head 41 and hence toward the axial passage in the main supporting shaft 33, the latter two elements being concentric. The wire stock 25 moves from right to left as viewed in Fig. 4.

The grinding head 41 is provided with a pair of grinding

wheels

48 and 49 which are mounted, as in Fig. 4, on opposite sides of the axis of the main supporting shaft 33 and hence similarly with respect to the supporting head 41, said wheels'being in so-called face-to-face relationship, the faces of which are slightly canted with respect to each other. Individual motors are provided for rotating the grinding

wheels

48 and 49, as at 50 and 5 I, respectively. The rotors of these motors are coaxial with and rigidly secured to their

respective grinding wheels

48 and 49. The grinding

wheels

48 and 49 are thus arranged to grind the .wire stock 25 upon fiat faces 48a and 49a (Figs. f4 and 5) rather than upon their peripheral edges 48b and 499.

The grinding

wheels

48 and 49 are mounted for axial'movement in such a manner that they contact diametrically opposite surface portions of the stock 25 being ground. Also the grinding faces 48a and 49a, by virtue of the canting of the axes of the grinding wheels, are set at an acute angle to the direction of stock feed and to the axis of the main supporting shaft 33.

Said motors 50 and 5| are mounted in the manner illustrated in Fig. 5 wherein the mounting for motor 59 is shown in detail. This mounting comprises a cylindrical outer housing 52 which surrounds a cylindrical inner housing 53, the latter enclosing a stator 54 and a rotor 55 which is mounted upon a rotor shaft 55. The'latter mounts the grinding wheel 48. The inner housing 53 is adapted for axial sliding movement in the cylindrical outer housing 52 but is restrained from angular movement therein by virtue of the key 51 which is secured to the housing 53 and engages a suitable groove in the hous ing 52. I

The canting of the axes of the grinding wheel 48 is accomplished by securing the outer housing 52 'tothe supporting head 41 by means of a wedge-shaped member 58 which may be formed integral with a mounting plate generally indie cated' at 59 which may form a part of the outer housing 52. 'It is preferable for the mounting plate 59 with its wedgeeshaped portion 53 to engage a suitable recess formed in the supporting head'41 and'to be secured therein in "a weilknown manner, as by bolts. The mounting for motor5| 'is analogous to that of motor 59. Thus each grinding wheel and its associated driving motor is mounted as a unit and is axially adjustable toward and away from the stock being ground in a manner to be explained more fuily hereinafter.

A coolant or a lubricant solution to facilitate the'grinding is supplied to the stock at the region of abrasion by means of a supply conduit 50 having branches GI and 62respectively directed to the grinding heads 4! and 42.' In Fig. 4 there is shown in detail a nozzle 63 for directing such solution onto the region'of the stock undergoing grinding, and also onto the stock prior to the time it is abraded by the grinding wheels. The stock 25 passes through a' suitable passageway in a ring 65 of the nozzle 65, thence through the passage in the'nozzle 64, and thence to the grinding wheels. The grinding solution thus is directed onto an side's'of thewire stock 25 prior to the time that it emerges from the nozzle 64. In order to retain the solution for recirculation and reuse, a bowl member or a bowl-like retaining vessel, having an aperture formed in the center of the bottom thereof for the passage of the wire, is provided as at 61 and may be secured to the main supporting shaft 33 by any suitable means. Said aperture in the bottom of the bowl member 61 is shown as at 68, the latter bein in register with the axial passage 33a formed in the shaft 33. Suitable hand controlled valves, as at I4, I5, are interposed respectively in the conduits BI and. 62 for controlling the volume of such solution directed upon the work-piece.

Referring again to Fig. 5, the grinding wheel 48 is mounted upon a metal plate I6 by means of suitable nuts I! and bolts I8. The mounting plate 16 is secured to a bed plate or motor disc I9 by bolts, one of which is shown at 89. ,The disc I9 is formed with a central bore for the reception of the outer extremity of the motor shaft 56, such extremity being indicated at 56c. A shoulder 56b is formed on said shaft to the left of the portion 56a, as viewed in Fig. 5, upon which said plate I9 rests and is held thereagainst by means of a cap plate BI and bolts 82. The motor shaft 56 is provided with roller bearings 83 for absorbing radial thrusts, said bearings 83 being at the righthand extremity of the shaft, as viewed in Fig. 5, and thus near that extremity of the shaft 56 which supports the grinding wheel 48.

The grinding wheel 48, in order to engage the wire stock 25, may be urged to the right (Fig. 5) and consequently a suitable thrust bearing as at 84 is provided for communicating thrust in such direction to the shaft 56' and hence to said grinding wheel. For aiding in disengaging the grinding wheel from the wire stock or in moving same to the left (Fig. 5),.a suitable bearing is provided for communicating thrust to the left from the housing to the shaft 56, such bearing being provided at 85. The inner ring of bearing 85 may, if desired, be rigidly held to the shaft 56 by means, for example, of an end plug 86. However, the operative interconnection between said bearing and the housing of the motor for communicating thrust to the left may include a bearing'plate as at 81 which surrounds the shaft 56 and by suitable shoulders at 88 contacts the outer ring of said A portion ofthe outer cylindrical surface of the inner housing 53 is threaded, as at 5311, and such threaded portion is embraced by an annular shaped gear 96 having a toothed periphery and a threaded inner surface, the latter being designed for threaded engagement :with said threaded portion 53a. It is clear, if suitable means, comprising for example the key 51, are provided for preventing angular movement of the inner housing 53 and for preventing axial movement of the gear 96, that angular movement of the latter will be translated into axial movement of the housing 53 and hence the grind-- ing wheel 48 which is axially movable therewith. The means for restraining said gear 'from axial movement comprise, in the form shown.

a pair of flanges 91 and 98 which are situated-'- fixedly adjacent opposite faces of the gear 96.-q

The flange 91 preferably is formed integral with the outer housing 52 and surrounds the latter. The flange 98 is rigidly secured relative to the flange 91 by any suitable means wherebythere is no relative movement therebetween. Suitable bearings are interposed between the flanges 91 and 9B and the gear 96. Thus, a bearing ring, 99 is interposed between the flange 91 and the gear 96 and a ball bearing as at I00 isinterposed between the flange 98 and said gear, the latter bearing having been found desirable in orderto assist in urging the grinding wheel to'the right as viewed in Fig. 5 and against the wire;

stock.

Referring to Fig. 3, the annular gear-96 is shown in connection with the motor 50and an bearing, said bearing plate 81 being operatively associated with the housing 53 by means of yielding members comprising springs 89 which surround arms 90, the latter being connected to the bearing plate 81.

The stationary outer race or ring of the hearing 83 is embraced by a flanged bearing plate 9|. The latter is secured to an annular or ringshaped member 92 by any suitable fastening means as at 93. Member 92 is rigidly secured, as by welding, to the inner housing 53. The inner face of the ring 92 is provided with a stepped surface 92a-for the reception of a bearing plate 94, the later being removable for disassembly purposes upon the unfastening of the means 93 and the removal of the bearing plate 9|. The bearing plate 94 provides along the inner margin thereof a shoulder for communicating thrust to one of the rings of the bearing 84, said thrust being to the right (Fig. 5) and being communicated to the shaft 56 via the other ring of bearing 84 and via a flanged sleeve 95. the latter engaging the shoulder 56b via the inner race of the bearing 83. v

analogous gear IN is shown in connection with? motor 5|, the latter being operatively associated with this motor in a manner analogous to that of gear 96. Means are provided for simultane-r ously shifting said gears 96, IOI angularly in order to move the grinding

wheels

48, 49 axially in opposite directions. Said means comprise acommon adjusting or screw-down motor I02 (Figs. 3; 6 and '7) which is securely mounted upon the supporting head 4T, as shown in Fig.1 6, wherein motor I02 is supported in a suitable aperture near the margin of said supporting head 41. The motor I92 transmits torque simultaneously to said gears 96 and NH by an operative interconnection consisting of the following: A worm I93 secured to ashaft I94 of the motor I02 is in engagement with a worm wheel I05 which is keyed to a shaft I06 To the latter shaft there is also keyed a piniongear I 91 which meshes with a pinion gear of substantially larger die ameter as at I08, the latter in turnbeing in;v

keyed engagement with a supporting shaft I09;

The elements I03-I08 thus constitute a reduction gear train for very substantially reducing the R. P. M. of the motor I92. Because of the above-described canting of the axes of the motors 58 and 5| and the grinding

wheels

48 and 49, it is necessary to employ universal couplings H0 and III for respectively interconnecting the shaft I89 with the remaining portions of the operative interconnection to said gears 96 and IIII. The universal coupling IIO communicates the torque of shaft I69 to a shaft II2 mounted in a suitable bracket I I3 and having secured thereto a chain sprocket gear I I4. The latter, by means of a chain belt II5, interconnects the gear II4 to a chain sprocket I I6, the latter in turn being secured to a shaft II'I upon which there is also secured a pinion gear II8 which meshes with said gear 96. I

. The coupling III for the gear IN is operatively grinding heads, corresponding to motor interconnected to :the latter by analogous means. It is understood that the threading ,uponthe innerhousings of =thezmotorsfl and 5| is such that actuationsof the. motor I82 will cause .the grinding wheels to move axially and concurrently in opposite .directions.

The slip ring structures for communicating electrical energy .to .the three motors :of each grindinghead are shown at .I I9, .128 of Fig. 1.

'In operation, the grinding wheels are separated by :asuflicient distance. by appropriate actuation of the screw-down motors as explained below, to permit free passage of the wire stock 25 while the latter is being threaded through the machine whereupon the motor 36 is started for rotating :the grinding wheels .planetarily around the wire stock, at which time thescrew-down motors, such as I82, may be actuated to move the grinding wheels, such" as 48, 49, to a point where they :engage the wire stock, the motors of the grinding head 4I being adjusted for a rough cut"-and the motors for the head 42 being ad justed for a finish out.

Due to the high reducing action of the gear train and the related operative interconnection between the adjusting motor, such as I82, and the inner housing of the motors 58, 5I, it is possible to control the movement of the grinding wheels with substantial accuracy because a single revolution of the motor I82 provides a very minute axial movement of said grindingwheels.

Reference will now be had to Fig. 8 for a description of the automatic regulator circuit for adjusting and maintaining the stock being ground at the gauge desired. Motor pairs I15, I18 and I11, I18 are the grinding motors that drive the opposed pairs of abrading discs, corresponding to motors 58, 5|, Figs. 3 and 4, motors I15, I18 being mounted on the left grinding head and motors I11, I18 on the right grinding head as viewed in Fig. l. Motors I19, I88 are the screw-down motors of the left and right I82, Figs. '3, -6 and 7, for adjusting the spacing between the grinding wheels, such as 48, 49, Fig. 3, in accordance with the required gauge to which the stock is to be ground. These are all three phase induction motors, energized from three phase supply lines, such as I8I, I82, knife switches I83, I84, being provided for disconnecting the power.

During the grinding operation, the grinding motors I to I18 inc. are normally running continuously while the screw-down motors I19, I88, are normally at rest. To this end motors I15 to I18 inc. are connected directly to the power supply lines I8I, I82, through-conventional pushbutton actuated start-stop connections omitted for simplicity of illustration. Each of the screw-- down motors, I19, I88, is connected, on two of its phases, to supply lines I8I, I82, through front contacts and armatures of a pair of control relays I85, I86 and I81, I88, respectively, and in the manner shown at I89 and I98. These connections are such, as shown, that when relays I85 and I81 are energized, motors I19 and I88 are connected to the supply lines in phase rotation'such, that the screw-down motors adjust the pairs of grinding motors and grinding discs toward each other on the grinding heads, thus to decrease the gauge of the stock being ground, this adjustment being effected as described above in connection with Figs. 3' to 7 inc. On the other hand when relays I86 and I88 are energized, the phase-connections to the spacing motors-I 19,

I88, are interchanged, as compared to the operation of relays I and I81, whereby these screwdown motors are energized to rotate in the opposite direction to that first described and thus back the pairs of grinding motors and discs away from the stock thus to increase the gauge thereof.

Relay pairs I85, I88 and I81, I88 are energized respectively from direct current supply lines I9I, I92 and I9Ia, I92a, being bridged thereacross in series with normally open and normally closed contacts of the pairs of push-buttons I93 and I94, I95 and I98, I91 and I98, and I99 and 288, the pairs I93 and I98, I94 and I95, I98 and I99, and I91 and 288 being ganged as shown. Thus when push-button I93 is depressed relay I85 is energized, and similarly for relays I88, I81, I88 upon depression of push-buttons I95, I98, 288. Owing to the gauging arrangements only one relay of each pair may be energized at a time. Thus .by manipulation of these push-buttons the grinding motors and discs on each grinding head may be displaced toward or away from the stock, manually to adjust the gauge being ground, as desired. For indicating the load on each grinding motor, ammeters are coupled to a supply line of each through current transformers, as at'28 I, 282.

For providing automatic gauging, the screwdown contact relays I85, I86, are placed under control of a regulating relay or regulator 283; and similarly the screw-down control relays I81, I88, are placed under control of a regulator 284. These regulators are of a conventional construction obtainable from the General Electric Company under the designation electrode regulator." Each regulator 283, 284, is provided with a pair of magnetically coupled coils 288, 281 and 288, 289, wound on a common armature as shown, but

in opposed relation, such that equal currents flowing in the same direction therein, respectively, will produce equal and annuling fluxes, thus to position a pivoted contact arm M2 .or 2I3, midway between its left and right fixed contacts. Conversely an increase or decrease in current flow through one coil 288 or 288 of each meter, over that of the other coil 281 or 289, will swing the associated contact arm 2I2 or 2I3, against its left or right hand contacts as the case may be;

The energizing circuits for the control relays I85, I88, and I81, I88, are traced from the positive power leads I 9i I8Ia, through a front contact and armature of a relay 2, as explained below and thence, for control relays I85 and I81, through the left hand fixed contact and contact arms, respectively, of regulators 283, 284, and for control relays I88, I88, through the right hand fixed contact and contact arms, respectively, of the regulators 283, 284, all circuits traced ex tending thence to the negative power lead I9I, either directly or over connections I92a. It will thus be seen, assuming relay 2 I I to be energized to close through the power leads I9Ia, that so long as the regulator contact arms 2I2, 2I3, remain in their median or neutral positions midway between their left and right fixed contacts, that all of the screw-down control relays will remain deenergized. On the other hand if the regulator contact arms 2I2, 2I3, swing against their left hand fixed contacts, the screw-in relays I85, I81, will be energized, in turn to energize the screw-down motors I19, I88, to advance the grinding head motors I15, I15 toward each other, and the same for motors I11, I18. Conversely if the regulator contact arms swing against their right hand fixed contacts, the con-: trol relays I86, I88, will be energized to back the grinding head motors of each pair away from each other, as above explained.

Coil 206 of regulator 203, is energized in proportion to the current supplied to the'grinder motors 115, 116, over a circuit 212 which includes a current transformer 213 coupled to one of the supply lines 181. The output of current transformer 213 is fed to a shunt rheostat 214, of the rotary type, and thence through a step-up transformer 215 to the input terminals of a full wave rectifier 216, such as a dry rectifier of the solenium type, the output terminals of which are connected to winding 206 of regulator 203.

A rectified current proportional to the voltage supplied to the grinder motors 115, 116, is supplied to the coil 201 of regulator 203, over a circuit 211 which includes a step-down transformer 218, a rotary type potentiometer 213, a full wave rectifier 220, the output terminals of which are connected across the fixed arm of a potentiometer 221, the variable arm of which is tapped across coil 201, as at 222.

The connections to

coils

206 and 201 are such that the magnetic flux produced by the resulting rectified current flow in coil 206, opposes the magnetic flux produced by the resulting rectified current flow in coil 201. As above stated the current fiow in coil 206 is proportional to the load current taken by the grinding head motors 115, 116, while the current flow in coil 201 is proportional to the voltage impressed on these motors. As explained below, the contact arm 212 of regulator 203, is initially and manually adjusted to its median or neutral position by means of the rheostat 214, at the load current taken by the grinder motors 1 15, 116, when grinding the stock to the desired or preselected auge.

The circuits for regulator 204 are similar to those above described for regulator 203, and hence require no detailed description. Thus coils 206, 209 are current and voltage coupled respectively to the supply line 182 through full

wave rectifier circuits

224 and 225, similar to 212 and 211. Circuit 224 includes a shunt rheostat 228, similar to 214 of circuit 212. The rotary arms of these rheostats are respectively mounted on shafts 229, 230, of

reversible motors

231, 232, which are reversibly energizable through field coils 233, 234 and 235, 236 of these motors, respectively. Motor 231 may be manually controlled to rotate in one direction or the reverse by means of

pushbuttons

231, 238, through the contacts of which the

motor field windings

233, 234, in series with the motor armature, are respectively connectible to an alternating current supply line 239. The

field windings

235, 236 of motor 232 in series with the armature thereof, are similarly connectible to the supply line 239, through the contacts of push-

buttons

240, 241 and over

connections

242, 243, to the supply line 239.

In addition to the manual adjustments of rheostats 214, 228 effected in the manner above described, they may be automatically adjusted in accordance with the preselected gauge to which the stock passing through the grinding apparatus is to be ground. This is accomplished by means of the equipment shown in the lower right portion of the drawing and including a regulator 244, having a pair of magnetically coupled energizing

coils

245, 246, poled in opposed relation. These coils act differentially on a pivotally mounted needle 241, adapted to swing between left and right pairs of contacts 248, 249, thus concurrently to energize the

rheostat motors

231, 232, through their lower 10 or

upper field windings

234, 236 or 233, 235. depending on whether the regulator needle swings left or right from a median or zero position.

These energizing circuits are traced from one side of the supply line 239 through contacts 210 of an interrupter 211, as described below, thence over connection 212 to the needle of regulator 241and through the meter contacts to the motor windings, returning thence through the motor connection to the opposite side of the supply line.

The regulator coils 245, 246, are respectively connected to a pair of similar photo-cells or

tubes

250, 251, by means of the obvious connections 252 shown, which include a common or center tap return path. The photo-

cells

250, 251, are energized from a light source 252, through

lens systems

253, 254, which

direct beams

255, 256, onto the photo-

cells

250, 251, respectively. These beams are focussed in front of the cells, as at 260, 261. Just beyond the focus point for beam 256, there is interposed in the path of the beam a wire or rod 262 of precisely the gauge to whichthe stock passing through the grinder is to be ground, the stock itself being fed, as at 263, through the path of beam 255, at a position correspondin to that of the standard gauging element 262 in beam 256. Thus the standard gauging element 262 and the stock 263 to be gauged cast greatly magnified shadows on photo-

cells

251 and 250 respectively.

If the stock 263 being gauged is of precisely the same diameter as the standard gauging element 262, the shadows cast on photo-

cells

250, 251, will be equal, producing equaland opposed direct currents in the meter coils 245, 246, in consequence of which the regulator needle 241 will remain in the neutral or median-position shown. If on the other hand the stock 263 being ground becomes over gauge or under gauge, the shadow area cast on photo-cell 250 will'increase or decrease with respect to that of cell 251. This will produce a net current fiow through the regulator coils 245, 246, the direction of which will depend on the direction of unbalance, thus to swing the regulator needle left or right as the case may be against contacts 248 or 249. The

rheostat motors

231, 232 will accordingly be energized to rotate clockwise or the reverse, thus compensatively to adjust the rheostats 214 and 228. This in turn will correspondingly vary the current flow through the current measuring coils 206, 208, of

regulators

203, 204, the contact arms of which will in turn swing left or right from the median position, and against the associated left or right contacts of each. Assuming relay 21 1 to be energized, the motor control relays and 181 or 186 and 188 will thus be energized, in turn to energize the screw-down motors 119, 130, in one direction of rotation or the reverse, compensatively to adjust the grinding motors 115, 116 and 111, 118 either away from or toward the stock being ground, as the case may be, until the gauge of the stock 263 being ground has been readjusted to that of the gauging standard 262, whereupon the contact arms of

regulators

203, 204, and 244, will swing back to their median or zero positions, thus to deenergize the rheostat and screw-down motors 231,232 and 119, 180.

For arranging the control circuit for either manual or automatic gauging control, as desired, relay 211 connected over conductors 261, and thence through a step-down transformer 268 and switch 269 to the A. C. supply line 239. Accordingly when switch 266 is open, relay-211 is deenergized, thus to open the supply line 191a,

thcreby preventing the regulators. 203, see from energizing any of the, spacing motor relays I85+I88 inc., which are thus energizable only by the manual actuation of the push-buttons .I93,2B0. On the. other hand when switch 269 is closed to energizerelay 2| I and connect the sup- ,pl'ylineISIa to the regulator contacts, the circuit to the rheostat motors MI, 232 via connection Thus the rheostat motors are energized step-by-step fashion to effect the gauging balance without over-travel;

In the operation of the gauging control circuit, the stock to be centerless ground, is threaded through. the centerless grinder in the manner .manually. adjusted by means of the push-buttons I93--200 inc., untilthe desired reduction of the ground stock is being obtained, this beingeffected by manual gauging of the stock as it passes through the apparatus. During this adjustment the indicating ammetersZilI, 202 are referred to for an indication of load balance.

When the proper gauge is attained, the knife switch 2'52 in supply. line239-is closed, and the regulators 2S3 and-.204 manually. adjusted to their median or zeropositions, by means of thepush-buttons 231 tol inc.,v controlling the. rheostat motors MI, 232. Thereupon'switch 269. is closed thus cutting the-system over to automatic regulation as above described.

The. ensuingoperation of the automatic regulating circuits is as follows. Assume that the machine is running and that. the. load adjusting rheostats 2M, 228, have beenset for the desired load in the manner above explained, and as will be'indicated. by the

volt meters

213, 214, connected in shuntrespectively to the current measuring coils 206,v 2080f the regulators 283, 204, the contact arms 212, 2I3 of which will now be in their median or zero positions. As the load on the machine increases, the voltage produced by the current transformers 2I3, 2I3a increases. This voltage is stepped up by transformers 2I5, 2I5a, and rectified by the full wave rectiflers ZIB, 2I6a. The resulting rectified voltages increasingly energize the current measuring coils 206, 2.08, of the regulating relays 203, 284, so that the. resulting magnetic fluxes produced by these coils, overbalances the fluxes produced by the opposing coils 201, 208 respectively. This causes the contact. arms 2| 2,, 2 I3 to Swing against their right hand. fixed contacts, thus in turn to energize the control relays I86, I88, in turn to energize the screw-down motors I19, I89, in such direction of rotation as tov cause the grinding motors I15, I16 and I11, I18, to back away from the stock being ground, until the load on thegrinder head motors is restored to it initial value. Should thereafter the load on the machine decrease, the voltage across the regulator coils. 206, 208, will correspondingly decrease, and the. resulting decrease in magnetic fluxes pro duced thereby, will cause the overbalancing fluxes of

coils

201, 209 respectively to swing the 12 regulator contact arms H2, H3, against their left hand fixed contacts respectively, thus to energize the control relays H35, I31, in turn to energize the screw-down motors I19, I89, in the reverse direction to that aforesaid, to now advance the grinder head motors toward each other, until a condition of balance is again restored.

The fact that the voltage energized coils 261, 2119 of the regulators are connected in opposed relation respectively to their associated current energized coils 2E5, 298, causes the regulator contact armsZlZ, 2H; to jog as the desired load is approached. This prevents overtravel of the screw-down mechanism. Also as stated, the interrupter contacts 215, are interposed in the energizing circuits for the rheostat motors 23!. M2, when under control of the automatic regulating relay 244, in order to allow current to flow therethrough only for predetermined intervals. thus additionally lessening the possibility of overtravel of the rheostat motors, and correspending overor under-adjust1nent of the load adjusting rheostats 2M, 223.

The Fig. 8 circuit arrangement actually embodies two automatic sizing control circuits for each set of grinder head motors, namely that of regulator 263, for the grinder head motors I15, I16, and that of regulator 204 for the grinder head motors I11, I18, 011 which is superimposed the overall control circuit of regulator 2M, applicable to both sets of grinder head motors. The circuit of regulator 2 responds more quickly to changes in the gauge of the stock being ground, than do the regulators of

circuits

263, and 2%, so that at no time can regulators 203 26 3 take over the automatic regulation control, unless the necessary response is called for by regulator 24 3. On the other hand, since the stock is being ground at two diiferent points, namely at one. point by the grinding motors I15, I16, and at another point by the grinding motors 511, I18, it becomes necessary to anticipate or determine which of the two grinding units may require adjustment, or perhaps both, at any given instant. To this end the balanced circuit arrangement due to the opposing coils 2%, 2i]? and 268, 289 for regulators 293 and 20%, provide individual regulation for the two grinding heads, which are extremely sensitive to changes of current in the respective sets of grinding head motors, viz. I15. I15 on the one hand, as compared to I11, I18 on the other. For retarding any undue fluctuations of current in the current measuring coils 205, 2&8, such as would not warrant a change in adjustment of the grinding heads, choke coils 236, 2880/. are bridged across the transformers 2i5, 255a respectively which choke coils thereby act as snubbers.

What is claimed is:

1. A gauge adjusting and automatic regulating apparatus for grinding and polishing machines having a motor driven abrading element for surface grinding elongated stock, said apparatus comprising: means including a reversible screwdown motor for relatively displacing said abrading element toward and away from said stock; a pair of switching means for selectively energizing said motor in one direction of rotation and the reverse for positioning said abrading element to grind said stock to a preselected gauge; and means for thereafter automatically controlling the positioning of said abrading element to maintain. said gauge, said means including a relay having a contact arm deflectable in one direcawait? tion between fixed contacts, to actuate one said switching means and deflectable in the opposite direction to actuate the said second switching means; a gauging element for continuously gauging said stock; and means responsive to said gauging element for oppositely energizing said relay in response to variations in the gauge of said stock above and below said preselected gauge and in such direction as to compensate for said variations through compensatory adjustments of said screw-down motor.

7 2. A gauge adjusting and automatic regulating apparatus for grinding and polishing machines having a motor driven abrading element for surface grinding elongated stock, said apparatus comprising: means including a reversible screw-down motor for relatively displacing said abrading element toward and away from said stock; a pair of switching means for selectively energizing said motor in one direction of rotation and the reverse to position said abrading element to grind said stock to a preselected gauge; and means thereafter automatically controlling the positioning of said abrading element to maintain said gauge, said means including a relay having a contact arm deflectable in one direction between fixed contacts to actuate one said switching means and deflectable in the opposite direction to actuate the second said switching means; means for adjusting said relay to a neutral position of deflection according to said preselected gauge; a gauging element for continuously gauging said stock; and means responsive to said gauging element for oppositely energizing said relay in response to variations in the gang of said stock above and below said preselect- 'ed gauge, and in such direction as to compensate for said variations through compensatory adjustments of said screw-down motor.

' '3. A gauge adjusting and automatic regulating apparatus for grinding and polishing machines having a motor driven abrading element for surface grinding elongated stock, said apparatus comprising: means including a reversible screw-down motor for relaaively displacing said abrading element toward and away from said stock; a pair of switching means for selectively energizing said motor in one direction of rotation and. the reverse to position said abrading element to grinding said stock to a preselected I gauge; and means for thereafter automatically controlling the positioning of said abrading element to maintain said gauge, said means in 1 eluding a relay having a contact arm deflectable in one direction to actuate one said switching means and deflectable in the opposite direction to actuate the second said switching means, and

-- having a pair of magnetically coupled and opposed energizing coils for said contact arm; a power supply circuit for energizing said abrading element motor, and circuits current and voltage coupling the same to said relay coils, respectively, and means for adjusting currents in said coils to equality for adjusting said contact arm to a neutral position of deflection according to said preselected gauge; whereby said relay thereafter responds, to variations in current supplied to said motor compensatively to actuate said relay and thereby adjust the positioning of said abrading element through compensative adjustments of said screw-down motor.

4. A gauge adjusting and automatic regulating apparatus for grinding and polishing machines, comprising the combination with means "for feeding elongated stock and a motor driven fabrading element for surface grinding said stock, of means including a reversible screw down motor for adjusting said abrading element against and away from said stock surface; means for adjusting ,said screw-down motor 1 to position said abrading element to grind said stock to a preselected gauge, and means for automatically maintaining said gauge, including'a first relay having a contact arm deflectable'between oppositely disposed fixed contacts for opipositely energizing said -screwdown motor, and having a pair of magnetically coupled and opposed energizing coils for said contact arms, a power supply circuit for energizing said abrading element motor, and circuits current and voltage coupling the same to said relay coil respectively, means for adjusting the current in said coils -.to a condition of balanced opposition at the load current value of said abrading element motor when grinding to said preselected gauge thus to adjust said relay contact arm to neutral at said load current value, whereby subsequent variation of said load current above and below said value, oppositely deflects said relay contact arm'compensativelyto adjust said screwdown motor until said value is restored. 3

5. In a surface grinding and polishing machine having means for feeding elongated stock and a motor driven abrading element for surface grinding the same, a gauge adjusting and automatic regulating apparatus comprising: a reversible screw-down motor for adjusting said abrading element against and away from said stock surface, switching means for adjusting said screwdown motor to position said abrading elementto grind said stock to a preselected gauge, and means for automatically maintaining said gauge including a first relay having a contact arm pivoting between oppositely disposed fixed contacts for oppositely energizing said screw-down motor, and having a pair of magnetically coupled and opposed energizing coils for said contact arm, a power supply circuit for energizing said abrading element motor, and circuits current and voltr' age coupling the same'to said relay coils respection between said contacts at the load on said abrading element motor corresponding to said preselected gauge, and means for automatically maintaining said adjustment including a second relay like the first, having a contact arm pivoting between fixed contacts for oppositely energizing said rheostat motor, a gauging element for continuously gauging said stock, and means responsive to variations of said gauging element above and below said preselected gauge for oppositely energizing said second relay and thereby said first relay, thereby compensatively to adjust said screw-down motor and abrading'element.

6. A gauge adjusting and automatic regulating apparatus for grinding and polishing machines having a motor driven abrading element for surface grinding elongated .stock, said apparatus comprising: means including a reversible screwdown motor for relatively displacing said abrading element toward and away from said stock; a pair of switching means for selectively energizing said motor in one direction of rotation element to grind said stock to a preselected gauge;

and .-means tor: thereafter automatically controlling, the positioning of said abradin'gi element to..maintain. saidgauge, said means including a regulator having a pivot-ally.- mounted contact arm defiectable in one direction to-actuate one saidlswitching. meansv and: defiectable in. the. opposite directionto actuate the. second said switchingmeans, a gauging elementv for continuously gauging said.- stock, and means responsive to said gauging element for selectively deflecting said regulator contact arm in responseto variations in. the gauge of said stock and in such directl'on as to compensate for said variations through compensatory actuation of said screw-down motor.

7'. A gauge adjustingand automatic regulating miparatusv for grinding and polishing machines having. a motor driven abradingelement for surfacegrinding elongated stock, said, apparatus comprising: means including a reversible screwdown motor forrelatively displacing, said abrading element toward and away from said stock; a pair-of. switching means for selectively energizing said motor in one. direction of rotation. and the reverse; means for manually actuating said switching means to position said abrading element to grind said stock to a. preselected gauge;

and means for thereafter automatically controlling the positioning. of said abrading element to maintain said. gauge, said means including a regulator having a p-ivotally mounted contact arm deflectablein onedirection to actuate one said switching. means and deflectable in the opposite direction to actuate the second said switching means, means for adjusting said regulator to a neutral position of. deflection according to said preselected. gauge, a gauging element for continuously gauging said stock, and means responsive to said gauging element for deflecting said -regulator contact. arminresponseto variations in Y the gauge of. saidstock, and in such direction as. tocompensate for said variations through compensatory actuation of said screw-down mo.-

ton.

8.. A gauge adjusting and automaticr'egulating apparatus for grinding and polishing machines having a motor driven abrading element for suriacegrinding elongated stock, said apparatus comprising: means including; a reversible screwdow'n motor for relatively displacing said, abrading element toward and. away from. said stock; a

pair of switching meansfor selectively energizing. said motor in one. directionof rotation and the reverse; means for manually actuating said switching means to position said abradng. element tov grind said stock to a preselected gauge; and. means for thereafter automatically controlling theipositioning of said abrading element to maintain said gauge, said means including a regulating relay having a pair. of magnetically coupled energizing, coils and. a pivotally mounted contact arm defiectable. thereby in one direction to actuate'one said switching means and deflectable inthe opposite direction to actuate the second said'switching means, a power supply circuit for energizing. said abrading. element motor, and

means current and voltage coupling said regulator. coils. thereto, respectively, and means. for adjusting. said. regulator relay to a neutral position of deflection according-to said preselected gauge; whereby said regulator thereafter responds. tofvariations in current supplied to said .moto'r, compensatively to adjust the positioning of saidabrading element through compensative actuation of said screw-down motor.

chines, comprising. the combination with means for feeding elongated stock and a motor driven abrading element for surface grinding, said stock, of means including a reversible screw-down motor for adjusting said abrading element against and away from said stock surface; manual' switching means for adjusting said screwdown motor to a preselected gauge, and means for automatically maintaining said gauge, including a first regulator relay having, a contact arm deflectable between oppositely disposed contacts for oppositely, energizing said screw-down motor and a pair of magnetically coupled energizing coils for controlling the positioning of said contact arm, a power supply circuit for energizing said abrading, element motor and circuits current and voltage coupling said regulator coils thereon, respectively, a rheostat in said. current coupling circuit and a reversible motor for adjusting the same; manual switching, means for reversibly energizing said rheostat motor, and means including a second regulator relay like the first and having a contact arm deflectable between oppositely disposed fixed contacts for automatically and reversibly energizing said rheostat motor, a gauging element for continuously gauging said stock, and means responsive to said gauging element for oppositely energizing said second regulator relay in response to variations of said stock gauge above and below said preselected value, thereby correspondingly to energize said first regulator for compensatively adjusting said screw-down motor.

10. In a surface grinding and polishing machine having means for feeding elongated stock and a motor driven abrading element for surface grinding the same, a gauge adjusting and automatic regulating apparatus comprising: a reversible screw-down motor for adjusting said abrading element against and away from said stock surface, switching means for manually adjusting said screw-down motor for a preselected gauge, and means for automatically maintaining said gauge inchding a first regulator relay having a. contact arm pivoting between fixed contacts for oppositely energizing said screwdown motor, and having a pair of magnetically coupled energizing coils for controlling said contact arm, a power supply circuit for energizing said abrading element motor, and current and voltage circuits coupling said power supply circuit to said coils, respectively, a rheostat in said current coupling circuit and a reversibl motor for adjusting the same, means for manually adjusting said rheostat motor for adjusting said first regulator contact arm to a neutral position between said fixed contacts at the load on said brading element motor corresponding to said preselected gauge, and means for automatically adjusting said rheostat motor including a second regulator relay like the first, having a contact arm pivoting between fixed contacts for oppositely. energizing said motor, a gauging element for continuously gauging said stock, and means responsive to variations of said gauging element above and below said preselected gauge for oppositely energizing said second regulator and thereby said first regulator, thereby compensatively to adjust said screw-down motor and abrading element.

11. In a machine for surface grinding elongated stock: means for feeding said stock and a motor driven abrading element for surface grinding the same, a reversible screw-down motor for adjusting said abrading element toward and away from said stock surface, switching means for manually adjusting said screwdown motor to a preselected gauge, and means for automatically maintaining said gauge including a first regulator relay having a contact arm pivoting between fixed contacts for oppositely energizing said screw-down motor, and having a pair of magnetically coupling energizing coils for controllably positioning said contact arm, an energizing circuit for said abrading element motor, and circuits current and voltage coupling the same to said regulator coils, respectively, said current coupling circuit including a rheostat for adjusting the current flow in the regulator coil coupled thereto, a reversible motor for adjusting said rheostat, switching means for manually adjusting said rheostat motor, and means including a second regulator relay like the first having a contact arm pivoting between fixed contacts for automatically adjusting said rheostat motor, a gauging element for continuously gauging said stock, and means responsive to variations in said gauging element for oppositely energizing said second regulator, and thereby said first regulator, compensatively to adjust said screw-down motor and abrading element, a control circuit including a manually actuated switch for converting said machine from manual to automatic gauging, an energizing circuit for said rheostat motor, including said contacts of the manual and automatic switching means therefor, and an interrupter interposed in said circuit.

12. A gauge adjusting and regulating apparatus for centerless grinders and the like having at least one motor driven abrading element for surface grinding elongated stock, said apparatus comprising: means including a reversible screwdown motor for relatively displacing said abrading element toward and away from said stock; a pair of relay switching means for selectively energizing said screw-down motor in one direction of rotation and the reverse; means for manually actuating said switching means to position said abrading element to grind said stock to a preselected gauge; and means automatical- 18 ly controlling the positioning of said element to maintain said gauge, said means including a first regulator relay having a contact arm pivotally defiectable between oppositely disposed fixed contacts for actuating said switching means, respectively, and having a pair of magnetically coupled energizing coils for controllably positioning said contact arm, means for energizing said regulator coils, respectively, in accordance with the current and voltage supplied to said abrading element motor, said means including said regulator coils and a rheostat for adjusting the current suppied to one said coil in accordance with the power required to grind said preselected gauge; a reversible rheostat motor for adjusting said rheostat, a pair of manually actuated switching means for energizing said rheostat motor in opposite directions of rotation, respectively, and means for automatically energizing said rheostat motor to compensate for variations in gauge of the stock being ground, said means including a second regulator relay like the first and connections therefrom to said rheostat motor for oppositely energizing the same in response to opposite deflections of said second regulator, a gauging element for continuously gauging said stock, and means responsive to said gauging element for deflecting said second regulator in response to variations in the gauge of said stock and in such direction as to compensate for said variations, said second regulator in turn correspondingly actuating said first regulator compensatively to adjust said screw-down motor and abrading element.

WALLACE K. LOWE.

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

UNITED STATES PATENTS Number Name Date 2,129,049 Doran Sept. 6, 1938 2,169,159 Moller Aug. 8, 1939 2,293,923 Stewart et al Aug. 25, 1942 2,383,927 Carlson Aug. 28, 1945 2,402,293 Nye June 18, 1946