Патент USA US2410295код для вставки
Oct 29, 1946- - H. P. KUEHN! EI'AL 2,410,295 AUTOMATIC PATTERN CONTROLLED MACHINE TOOL Fi'led Jan. 19, 1943 ' 3 Sheets-Sheet 1 _ mal Invento'r-s: Hans P. Kuehni, Norman 6. Bransqn. by M5. 1M4», ‘Thei’r- Attorney. ' Oct. 29, 1946. H.’ P. KUEHNI ETAL I 2,410,295 AUTOMVATIC PATTERN CONTROLLED MACHINE TOOL Filed Jan. 19, 1943 W6“ > ' I ,1‘ I I J7‘I ‘ I m u c. "nun-n rm‘ , l ' 3 Sheets-Sheet 2 ' | l‘: *. l I E‘ ~ * I ‘ ‘. Te | Inventor-s: -Hans F2 Kuehni, Norman G. Br-anson. Their’ Attorney. _ Oct. 29, 1946. H. P. KUEHNI! EI'AL ' 2,410,295 AUTOI'ATIC PATTERN CONTROLLED MACHINE TOOL Filed Jan. 19, 1943 3 Sheets-Shéet 3 @2 Inventor-s: Hans F.‘ Kuehni, Nor-man _ G. Branson, by Their; #64476Attorney. M“, Patented 0a. 29, 1945 Y ' 2,419,295v . 7 ‘UNITED I srarss PATIENT '0 FFICE] v 2,410,295 AUTOMATIC PATTERN CONTROLLED MACHINE TOOL ' . Hans P. Kuehni and Norman G. Brannon, Sche nectady, N. Y., “assilnors to General Electric Company, a corporation or New York . . Application January 19, 1943, Serial No.-4'l2,840 > . 8 Claims. (01. 172-—239) ‘This invention relates to automatic pattern controlled machine tools, more particularly to control systems for such machine tools, and a more speci?c object of the invention is the pro vision of asimple, reliable, and improved con trol system of this character. ~v More speci?cally, the invention relates to autos ‘ matic pattern controlled machine tools such as tracer device includes a magnetostrictive mem ber, i. e., a member whose magnetic permeability changes in response to- the application of a force to the member. This change in- permeability of the magnetostrictive member is utilized to pro duce a control voltage which in turn is utilized, ‘to control the driving means inv the manner, de scribed in the foregoing. further object of this invention is the provision 10 In illustrating the invention in one form there of, it is illustrated as embodied in a control sys-_ of means for eilecting a relative movement of tem for an automatic pattern controlled metal the cutter and work piece at a constant contour _ cutting lathe, and also in a control system for a speed for all angles of such relative movement polar co-ordinate type milling machine. , milling machines, lathes, and the like,‘ and a . so that the tool marks on the work will be evenly a better and more complete understanding spaced irrespective of the shape which is being 15 of For the invention, reference may now be had to cut. . ' the following speci?cation and to the accompany The ‘relative movement of the cutter and the ing drawings in which Fig. 1 is a simple, diagram work piece in machineftools of this character is matical illustration of an embodiment of the in controlled by means of a tracer device which is vention as applied to a lathe; Fig. 2 is a detailed ‘maintained in engagement with the pattern as 20 sectional view of the tracer element; Figs. 3 and it is moved along the pro?le thereof. 4 are simple, diagrammatical illustrations of the Another object of the invention is the pro sine and cosine regulators which constitute parts vision of a control system for a pattern controlled of- the control system; Fig. 5 is a chart of char machine tool in which the two components of acteristic curves which serve to explain the op the relative movement of the cutter and the work 25 eration of the invention; Fig. 6 is a'diagram piece .- are continuously correlated so that the matical sketch which illustrates graphically the movement is not a series of steps and a fine, step variation of the force between the pattern and less ?nish of the work is obtained. ' . ' the tracer finger at various angles; Figs. '7, 8, 9, In carrying the invention into effect in one 10, and 11 are charts of characteristic curves form thereof, means are provided for supporting '30 which illustrate the correlation oi'the speeds of the pattern and the work piece in operative rela the motors which produce the components of the tionship with the tracer and cutter, respectively. Suitable driving means controlled by- the-tracer are provided for effecting the relative movement relative movement of the cutter and work for the magnitude of either, and therefore, irrespective is a schematic diagram of an ampli?er which constitutes an element of the system. angles indicated in Fig. 6; Fig. 12 is a diagram matic sketch illustrating the constancy of the of the cutter and the work piece. This relative 35 velocity of the relative movement between the movement of the cutter and the work piece is the cutter and work at all angles of such relative resultant of two angularly displaced components, movement along the contour; Fig. 13 is a view in _e. g.-, a longitudinal movement and a transverse perspective illustrating an'application of the in - movement. Means controlled by the tracer con vention to a polar co-ordinate type milling ma trol the driving meansso that the vector sum 40 chine; Figs. 14 and 15 are diagrammatic sketches _ of the speeds of these two component'movements illustrating the operation of the invention as apis approximately constant irrespective of the plied to the milling machine of Fig. 13, and Fig. 16 - of the angle of the resultant movement. This is accomplished by controlling the driving means in 45. Referring now to the drawings, it is desired to response to continuous variation of the force be turn a metallic work piece to so that the ?nal tween the pattern and the tracer so that the pro?le will conform accurately 'to the pro?le of speed of one of these components is continuously the pattern i I. The work piece III, which may be ‘varied from a maximum value in one direction of steel or other material, is rotated by suitable to a maximum value in the reverse direction, de 50 driving means about a longitudinal axis de?ned pendent upon the magnitude of the force, and by the lathe centers 01' which only the tail stock the second‘ component is unidirectional and its ' center I! is illustrated. The driving means for speed is simultaneously varied in inverse rela-v rotating the ‘work maybe and preferably is a tionship to the speed of the?rst component direct current electric motor supplied from a In a specific embodiment of the invention, the 55 source of alternating voltage through suitable 9,410,295 3 . electric valve apparatus which may be controlled to adjust the speed of rotation of the work piece to a desired value. Since'the details of this motor and the electric valve control apparatus from which it is supplied constitute no part of the in vention, they are omitted from the drawings in the interest ‘of simplicity. The pattern II is supported by suitable means - 4 tension of which may be suitably adjusted by means of a threaded annular member 32, which is in internal threaded engagement with the wall, of the shell 23. The disk 30 is provided with an adjustable set screw 30a. A hollow cylindrical member 33 made of a mate rial possessing the property of magnetostrlction, such as nickel-steel, is arranged centrally within the cylindrical jacket 29 and is of su?icient length to project through the openings 23c and 23d 10 is ?rmly clamped by suitable means such as in the top and bottom caps 23a and 28b, respec clamping screws M. The supporting plate l3 tively. This magnetostrlctive element is ?rmly may be securely fastened to the bed of the lathe, ‘ illustrated as a plate ill to which the pattern II or may be built as an integral part of the lathe. held between the set screw 30a and the top sur A cutter I5 is held in a tool post it which is mounted in a compound rest comprising an upper cross feed member l1 which is slidably mounted on the cross feed slide of the carriage l8. The carriage I3 is slldably mounted on ways lSa vided with a rounded recess to receive the rounded for longitudinal movement along the bedplate IS. face of the horizontal flange of the tracer ?nger. As shown, the top surface of the ?ange is pro end of the cylindrical magnetostrictive element. If a force is applied to the contact point 23b of the tracer ?nger in any radial direction in a The longitudinal movement is e?ected by means 20 plane perpendicular to the longitudinal axis of the ?nger, a limited rotation of the ?nger 23 of a lead screw 20 and a. cooperating threaded about a point on the seating ring 24 as a pivot member (not shown) with which the carriage is will result. For example, if a force f1 acting to provided. ‘ ~ ward the left is applied to the contact point 23b. A tracer 2| is maintained in fixed but adjus the ?nger will be given a limited rotation in a table relationship with respect to the cutter by means of a rigid supporting arm 22 to which the tracer 2| is ?rmly secured and which, in turn, is rigidly secured to the cutter supporting means, i. e., the compound rest ll. ‘Thus the tracer 2i and the cutter l6 are supported in operative relationship, respectively, with the pattern 13 and work piece III. A preferred construction of the tracer device clockwise direction about the point 25c as a cen ter, and the ?anged head 25a acting as a lever will apply a force to compress the magnetostric tive member. Likewise, if a force )‘2 acting to ward the right is applied to the contact point 23b, the ?nger 25 is given a limited counterclockwise rotation about the point 2511 as a center, and the flanged head 25a will apply a force to compress the magnetostrictive member 33. Thus, the 2| is illustrated in Fig. 2. It comprises an outer tracer ?nger 25 acts as a bell crank to apply a cylindrical shell 23 which is formed of mild steel. compressional force to the magnetostrictive mem The upper portion of the shell 23 is bored to have ber 33 in response to the application of force a larger inside diameter than the inside diameter to the contact point 25b in any radial of the lower portion, thereby to provide a seat for direction in a horizontal plane. The compres a ring 24 which is preferably made of hard tool sion of the magnetostrictive element is therefore steel. A tracer ?nger 25 which is made of hard 40 independent of the direction of the force applied tool steel and has a shape which is generally to the tip of the tracer ?nger. In other words, similar to that of a poppet valve is mounted within the tracer is nondirectional. The application of the bore of the lower portion of the shell with a force to the magnetostrictive element e?ects a its ?anged head bearing on the hardened seating ring 24. The lower end of the finger 25 projects 45 change in its magnetic permeability. Within the jacket 29 and surrounding the through an opening in the bottom of the cylin magnetostrictive member 33 is a coil 34 which drical shell and is of tapering shape to provide is wound upon a spool 35 that is preferably made a cylindrical portion 25b which serves as the of a suitable phenolic condensation product, such contact point which engages the pro?le edge of the pattern. The clearance between the ?nger 50 as Bakelite. The magnetostrictive member and the jacket 23 form a magnetic circuit for the and the outer shell at the bottom may be made magnet ?ux produced by the coil. Leads 33 and quite small, e. g., .01 inch. A second hard steel 31 are brought out from the coil through open ring 26 rests upon the lower hard steel ring 24. ings in the top cap 29a, the disk 30, and the disk As indicated, the inside diameter of the ring 25 is greater than the inside diameter of the lower 55 shaped terminal bracket 33 which is clamped in place at the upper end of the shell by means of ring 2i so as to provide su?icientspace for the an internally threaded clamping ring 39 which ?anged head of the tracer ?nger 25. is in threaded engagement with the outside wall A cylindrical spacing member 21 made of hard of the shell 23 at the upper end thereof. The coil tool steel is fitted within a large diameter bore 33 constitutes one arm of a Wheatstone bridge, in the upper portion of the shell. This cylindri the remaining arms of which comprise the resis cal member is held ?rmly against the upper hard tor 40 plus the portion of resistor M at the left ened ring 26 by means of an annular member of the slider Illa, the resistor 42 plus the portion 28 which is in threaded engagement with the of resistor ll at the right of the slider, and the internal wall of the shell 23. Within the cylindrical spacing member 21 is a 65 coil 43. A periodically varying voltage of suitable fre clyindrical jacket 29 which may be made of any quency, e. g., 2,000 cycles per second is supplied to suitable magnetic material, e. g., one of the well the opposite bridge points Ma and 4311 from an known nickel-iron alloys such as Nicalloy or electric valve type oscillator 44. Any suitable type Permalloy. This jacket has a top cap 29a and a bottom cap 29b. These caps are provided with 70 of oscillator may be used. The constructional centrally disposed openings 29c and 29d, respec tively. details of the oscillatorare unimportant and the oscillator is therefore indicated conventionally in the drawings. ’ ' Above the screw ring 28 is a disk member 30 The Wheatstone bridge is initially balanced by made of hard tool steel. It is ?rmly seated on the ring 23 by means of a spring washer 3| the 76 adjustment of slider “a when no force is applied $410,095 v5 6 to the tracer ?nger and the magnetostrictive ele ment is prestressed. When a force is applied to the tracer ?nger, this force is multiplied and , portant characteristic of this time of valve is that when connected in series with a resistor across a source of variable voltage, the voltage drop across the terminals of the valve remains sub translated into a compressional force acting on the magnetostrictive member. The resulting stantially constant. change in permeability of the magnetostrictive member unbalances the Wheatstone bridge and Direct current power at a suitable voltage is supplied to the power input terminals 45c and 45! p or the cosine regulator from a suitable source causes a periodically varying voltage to appear across the opposite bridge points 40a and 42a. - such as the regulated power supply represented This unbalanced voltage is .applied to the input 10 by the two supply lines 45. A voltage divider com prising ?xed resistor portions 55a, 55b, 55c, and terminals of an electric valveltype ampli?er 45. 55d and a variable resistor portion 55s is con Preferably the ampli?er 45 is of the type which has a direct voltage output that is approximately . nected across the power input terminals 45¢ and 45)‘. The cathodes 52a and 52b oi.’ valve 52 and 55a linearly proportional to the e?ective value of the periodically varying input voltage. Direct current 15 and 53b of valve 55 are connected by means of sliders to points on this voltage divider of pro-‘ power is supplied to the power input terminals gresslvely increasingly positive voltage so that 45a and 45b of the ampli?er from a suitable the left-hand conducting path of valve 52 is source such as a regulated ‘power supply (not biased to cutoff, and the right-hand path of valve shown) which is conventionally indicated in the drawings by the two supply lines 45. The circuit 20 52 and both paths of valve 55 are biased beyond cuto? by progressively increasing amounts. The details of this ampli?er are illustrated in Fig. 16. grids of both valves are all connected together to As shown the ampli?er comprises two stages of’ the input terminal 49a, and the negative terminal voltage ampli?cation with a transformer output of- the cathode voltage divider is connected to the to a full wave recti?er. The ?rst stage is a'pen tode valve and the second stage is a triode valve. The two stages are coupled by means of capacita input terminal 49b. ’ The anodes 52c and 52d of valve 52 and 530 and 53d of valve 58 connect through parallel adjusta tive coupling, The A-C voltage input is supplied ble resistors 55, 51, 55, and 59, respectively, and to the terminals 45c, 45d and the D.-C. output through a series resistor 50 to the anode of valve voltage appears across the resistor between the terminals 45c and 45!. 30 54 which is connected to the positive power input Theirelationship between the force applied to terminal 49c. ~ ' the tracer ?nger and the output voltage of the The valve 54 is connected in series with a re ampli?er 45 is illustrated graphically by the sistor 5| across the power supply, and a_voltage divider comprising ?xed resistor 62 and adjust straight line curve 41 in Fig. 5, in which ordinates represent volts and abscissae represent force‘ act 35 able resistor 53 is connected across the valve 54. The power input voltage may be any suit ing on the tracer ?nger. This curve 41 indicates that the direct voltage output is approximately able value which may be assumed, for example, to be 300 volts. Accordingly, the voltage of the linearly proportional to the force acting on the terminal 54a is 300 volts positive. The slider 53a tracer ?nger. The 'output voltage of ampli?er 45 is applied 40 is initially adjusted to a point on the voltage di vider such that the voltage drop between termi simultaneously to the input terminals 48a, 45b, nal 54a and the slider is equal to the voltage 1 and 49a, 49b of two electric valve type regulators drop produced across the resistor 50 by the com 48 and 49, respectively, which are referred to as bined saturation currents of both conducting the ‘sine regulator and the cosine regulator, re spectively. The sine regulator is an electric valve ‘ paths of valve 52. Assuming this voltage drop to be 50 volts, the slider ‘53a will be adjusted to apparatus which has a direct voltage output which the 250-volt point on the voltage divider 52, 53, approximates a sine function of the magnitude and a net voltage of 50 volts will appear across of the direct voltage applied to its input term the output terminals 490 and 49d when both inals. That is to say, that as the voltage applied to the input terminals 48a and 45b varies con 50 valves 52 and 53 are at cutoff. This is the maxi mum positive output voltage of the cosine regu tinuously and linearly from a minimum value to lator and it exists when the force on the ‘tracer .a higher value, the voltage at the output term-' ?nger is zero, as indicated by the point 5la on inals 48c and 48d of the sine regulator varies continuously from a minimum value to a maxi mum value and then to a minimum value, as in curve 5| in Fig. 5. As the force increases, the * voltage supplied to the input terminals 49a and Thecosine 49b increases ‘linearly and in accordance with regulator 49 is a similar electric valve apparatus, the direct output voltage at the output terminals 490 and 49d of which varies approximately as a cosine function of the magnitude of the direct voltage applied to its input terminals. Since the input voltages of the sine regulator and cosine curve 41. This causes the left-hand conducting ‘ - dicated by the curve ‘50 of Fig. 5. path of valve 52 to become conducting and to conduct an amount of current that increases as the input voltage increases. This increasing our rent-produces an increasing voltage drop across resistor 50 which is in opposition to the voltage between terminals 54a and slider 53a so that the regulator are the output voltage of the ampli?er voltage of ‘terminal 50a begins to decrease with 45 which is linearly proportional to the force ap plied to the tracer ?nger, the output voltage of 65 the result that the net voltage across output ter minals 49c and 49d decreases correspondingly. the’ sine and cosine regulators are therefore sine This is indicated in Fig. 5 by the negative slope ‘and cosine functions of the magnitude of this of curve 5i between the points 5la and MD. The magnitude of the current conducted by the left As indicated in Fig.3, the cosine regulator com prises a plurality of electric valves 52, 55. and 54. 70 hand conducting path of valve 52, and conse quently, the steepness of the curve 5| between‘ Although the electric valves 52 and 53 may be of force. - . . points 5la and Nb, depends upon the adjustment any suitable type, they are preferably twin triode of anode resistor 55. . valves of the "hard” tube type. The valve 54 is a When the force on the tracer ?nger increases cold cathode type diode valve containing a small amount of an inert gas such ‘as neon. The im 75 to the value b and the input voltage increases to 2,410,998 V a value corresponding to the height of curve II at point "I: in Fig. 5, the current in the left hand conducting path ‘01 valve 52 reaches sat nation. and the voltage across output terminals “c and “d is decreased to the value indicated by point lib on curve II. At this point, the rlghtdiand path of valve 52 becomes conducting. As the force on the tracer ?nger increases be yond the value b, the right-hand path of valve . ‘r8 . their Junction point Ila is connected to the posi tive power input terminal 48c. ' . ' when both valves are at cutoi! the voltage dif terence across the output terminals is zero. How ever, as the force on the tracer ?nger is increased from zero, the voltage from ampli?er ll is ap plied to the input terminals "a and no, and the left and right-hand paths of valve ll be come successively conducting and produce volt ll conducts an increasing amount of current with 10 age drops across resistor ll so that a net volt the result that the voltage drop across the re age appears across the output terminals llc and sistor 8| is iurther increased until the saturation ' lid. The portion of the curve ll between zero point is reached, which occurs when the force on and "b represents theoutput voltage as the the tracer ?nger has a value corresponding to iorce increases from zero to the value b, and the the dotted line 0, Fig. 5. At this point, the‘volt 15 portion of the curve between the points at and age drop across resistor ill is equal to the volt 5,00 represents the output voltage as the force in age drop between terminal "a and the slider» 83a creases from b to c. As the force increases be with the result that the net voltage across the yond the value c both paths of valve I! become output terminals llc and lid is zero, which con successively conducting and produce a voltage dition is represented‘in Fig. 5 by the curve ,5! 20 drop across resistor 89 which is in opposite sense crossing the zero axis at'point llc. The slope to the voltage drop across resistor I8. and there oi‘ the curve 5| between points lib and Sic is. fore. decreases the net voltage at the output made greater than the slope between 51a and Bib terminals. The portion of curve 50 between by adjusting the'resistor 51 to a lower value than points 500 and 50d represents the output voltage resistor ll. 25 as the force increases from value c to value d, As the force on the tracer ?nger is increased and the portion between the points 50d and He beyond the value c, the left-hand and right represents the output voltage as the force iii hand paths of valve 58 are successively rendered creases from value d to value c. conducting, and the voltage drop across resistor ‘Thus the force on the tracer ?nger increases 80 is correspondingly increased with the result 30 linearly from zero, the output voltage of the that the terminal 80a becomes more negative cosine regulator it varies continuously from a than the slider 83a, thereby reversing the po maximum positive value to a maximum negative larity ol'the voltage across the output terminals. value, and the magnitude or the output ‘voltage With increasing force on the tracer ?nger the‘ of the sine regulator 48 is simultaneously varied output voltage takes on the successive values in 35 continuously but inversely to the magnitude of dicated by the negative half of curve 5| until at the output voltage 01' the cosine regulator. How a force corresponding to dotted line e, both con ever, the polarity of the output voltage of the ducting paths of valve 51 are saturated and the sine regulator does not change. voltage drop across resistor 60 is twice the volt The transverse movement or the cutter i8 is age drop between terminal 54a and slider 63a, 40 effected by means or an electric motor 10, the so that the net voltage across the output termi drive shaft of which is connected to the cross nals 49c and 49d is equal in magnitude and op slide ll of the lathe through suitable driving con posite in polarity to the maximum positive volt nections illustrated as comprising worm gearing age. This maximum negative voltage is repre H, shaft 12, bevel gearing ‘l3, and a lead screw sented in Fig. 5 by the point 5le, the ordinate of which is equal to but opposite in sign to the Although the motor Til may be of any suit ordinate of the point iila which represents the able type, it is illustrated as a split series ?eld maximum positive voltage. Thus it is seen that direct current motor. Power is supplied to the by proper adjustment oi! resistors 56, 51, 5B, and motor "i0 from a suitable source of single phase II. the voltage output of the cosine regulator is alternating voltage which is represented by the caused to approximate a true cosine function of two supply lines 15 through a transformer 18 the magnitude 0! the force applied to the tracer and suitable electric valve apparatus comprising ?nger; ‘1A closer approximation, if desired, can the thyr'atron valves ll and ‘i8. These two valves be obtained by increasing the number of valves. ‘l1 and ‘iii are connected as half-wave recti?ers Thei sine regulator 48 is similar in most re and individually supply voltage to the motor spects' to the cosine regulator. It comprises two through one or the other of the split ?eld wind electric valves 64 and 85 which are identical with ings ‘Illa or 10b to effect rotation of the motor valves 52 and SI of the cosine regulator. The in the forward or reverse direction as required. grids of both valves are connected together to The anodes 11a and 18a of thyratrons Ti and ‘ID the input terminal 48a. A voltage divider com 60 are connected through the field windings 70a prising ?xed resistors 66a, 66b, 56c, and 56d and and ‘(0b in parallel and through the armature adjustable resistor tie is connected across the of motor 10' to the right-hand terminal of the power input terminals lie and 48!. The cath secondary winding of transformer 16, and the cathodes Tlb and 18b are connected to the left odes Na, 84b, 85a, 85b are connected to points hand terminals of the secondary winding. A on the voltage divider of progressively increas pair of resistors 19 and 80 is connected in series ingly positive voltage, so that the left-hand con relationship with each other across the control ducting path of valve 84 is biased to cutoff and grids 11c and lie, and the junction point 19a the right-hand path and both paths of valve 65 of these two resistors is connected through the are biased beyond cutoii' by progressively increas 70 active portion of a potentiometer resistor 8| be ing amounts. The anodes 64c and Bid or valve tween the terminal 19a and the slider 8|a to the 64 are connected to output terminal 48c, and the cathodes 11b and 181). A periodically varying anodes 85c and 65d are connected to output ter-. voltage is supplied from a source 82 through a minal “it. Two resistors 58 and 69 are con phase shifting bridge network to the potentiom nected in series across the output terminals and 75 eter Bi and thence to the control grids lie and 2,410,296 9 ‘m. The source’ "may be and-preferably is v the same source, as the source ‘I! to which the anodes are connected. As shown, the phase shift ing bridge network'comprises the opposite halves of the secondary winding of the transformer 83, the adjustable resistor 8.4, and the capacitor 85. By suitably adjusting the resistor 84, the alter nating component of voltage supplied to the con trol grids may be dephased with respect to the . anode voltage. Preferably the resistor “is ad Justed-so that the alternating voltage supplied to the control grids is dephased from the anode voltage by approximately. 90 degrees lagging, with ‘1o 1 , For the purpose of accurately regulating the speed 01' motor ‘III to a value correspondingto the instantaneous magnitude of the output voltage of the cosine regulator, means are provided for supplying to the grid circuit 01' the ampli?er valve 86 a signal voltage‘which is proportional to the ‘speed oi“ the motor 10 and opposite in polarity to the voltage supplied from the cosine regulator. This signal voltage is provided by means of a 10 tachometer generator 89 which is driven by mo~ tor ‘Ill and generates a voltage which is linearly proportional to the speed of motor 10. This sig nal voltage is applied across a resistor 90‘ in the the result that the thyratrons Ti and ‘I8 conduct grid circuit oi’ ampli?er valve 86 so that it op only during a small portion oi’ the positive halt 15 poses the voltage supplied from the cosine regu cycle of the voltage applied to the anodes 11a lator, and the di?erence of the two voltages is the . ‘ and ‘Ila. effective control'voltage on the grid of the am For the purpose of amplifying, the 'direct volt pli?er valve. The tendency of this feedback cir age output of the cosine regulator, a suitable am cuit is to regulate the signal voltage to the output pliiier comprising a-\tw‘in triode valve 86 is pro 20 voltage of the cosine regulator.‘ In other words, vided. Power is supplied to the power input ter it maintains the signal voltage approximately minals 88a and 86b of this ampli?er from a suit; equal to the output voltage of the cosine regulator. able independent D. C. source. The control grids I ‘Since the signal voltage is linearly proportional of this ampli?er are biased to provide push pull - to the speed oi’ motor 10, an equilibrium condi class A operation with both paths of the valve 25 tion is reached when the dlil'erence of the two conducting equal amounts of current through re voltages is just suiilcient to cause the motor 10 sisters 81 and 88. when a voltage’ is supplied to operate at a speed which accurately corre from the cosine regulator to the grids of valve sponds to the magnitude of the output voltage of 88, one path is caused to conduct more current - the cosine regulator. Since the output voltage oi than the other, depending upon the polarity of 30 the cosine regulator is a cosine function of the - the voltage from the cosine regulator with the magnitude of the force applied to the tracer result that the voltage drop across one of the ' finger, .the speed oi‘ the motor ‘Ill ‘will also be a resistors 81 and 88 is increased and the voltage cosine function or the magnitude of this force. drop across the other is decreased. As a result, The longitudinal feed lead screw is driven by a a direct current voltage'component in the posi 35 motor’ 9| which is controlled to operate. at a tive direction is applied to the grid of one of speed which is proportional to the magnitude of the thyratrons. This direct current component the output voltage of the sine regulator 48 by adds to the alternating current component sup means of electric valve apparatus shown within plied to the grid in such a direction as to have the dotted rectangle 92, This apparatus is iden the e?ect of advancing the phase of the grid 40 tical with the electric valve apparatus which con voltage thereby to render the thyratron conduct_ trols the cross feed motor 10, and accordingly. a ing by an amount proportional to the magni repetition of the description and operation of this tude of the voltage supplied from the cosine reg electric valve apparatus is omitted. The tech ulator to the ampli?er valve 86. At the same ometer generator 93 performsthe same function time, a direct current component is supplied to in regulating the speed of the longitudinal feed. the control grid 01' the other thyratron in such a 9| that is performed by tachometer gen direction that it further retards the phase of ‘ motor erator 89 in regulating the speed of the cross feed the grid voltage, and thus the thyratrons 11 and drive motor 10. '18 are selectively energized to e?'ect rotation of A voltmeter 84 is connected across the output motor ‘Iii in one direction or the other depending . terminals oi’ the ampli?er 45. The scale of this upon the polarity of the output voltage of the meter is so calibrated that each graduation cor cosine regulator. In the circuit shown whenthe responds to .00005'inch de?ection of the tracer output terminal 49c oi’ the cosine-(regulator is ?nger. The meter can thus be used as a very ac positive, the thyratron Tl is energized and that curate gauge for electrical adjustment of the current is supplied to the motor "H3 in such a , direction for example as to cause the tool [5 to be moved inward toward the work piece 10. cross feed of the compound rest for taking ?nish cuts. Since it is possible to estimate fairly ac curately one-halt the. distance between scale Conversely, when the output terminal 49d of the cosine regulator is positive. the thyratron graduations. the cross feed can be adjusted‘ to within .000025 inch of a desired position. This '18 will be energized and the motor 10 will be 60 degree of accuracy exceeds by a wide margin that caused to rotate in a direction to withdraw the obtainable by means otthe usual mechanical tool l5 from the work. The rotational response scales on, the cross feed adjustment of a lathe‘. may be reversed by means of a switch in lines The electrical adjustment consists in shifting the 49c, 49d as required. 7 bridge balance the desired degree by means oi’ the The ampli?cation ratio oi’ ampli?er 86 is such 65 potentiometer 4|. Also, the voltmeter 94 serves that a very small voltage; e. g., one volt across _ as an extremely accurate measuring device in set the output terminals of the cosine regulator- will fully advance the phase oi’ the grid voltage of one or the other of the thyratrons ‘I1 and 18. As a result, the active thyratron tends to supply a current to the armature of the motor ‘III which is several times full load value. This would tend oi’ course to accelerate the motor 10 to maximum ' ' speed for any output voltage of the cosine regu lator in excess of one volt. ' . ting up a templet on the templet supporting plates. Any lack of parallelism between the ion gitudinal edge, of the templet and'the center axis of the lathe and the amount 01 such divergence is readily indicated on the meter byv moving the tracer?nger along the longitudinal edges oi’ the template with no work piece in the lathe. With the foregoing understanding of the ele- ' 75 merits and their organization in the system, the ‘ 2,410,295 11 operation of the system will readily be under— stood from the following detailed description. It may be assumed that the tool and tracer are in position for starting a out. In other words, the . 12 teed motor 8 I. When the tracer point has moved through 45 degrees of are along the semicircular edge l3b, the force exerted on the tracer ?nger, attains the magnitude indicated by the dashed line b’ in Fig. 9, with the result that the cross feed motor 10 and longitudinal feed motor 9| operate at equal speeds as indicated in Fig. 9 by the intersection of the sine curve and cosine curve matic view of the portionof the pattern consti on the dashed vertical line b’. Since the speeds tuting the longitudinal edge i311 and the semicir cular edge I311. The tracer point 251) is in the 10 of both motors are equal, the tracer point and the cutter 15 will have a direction relative to the position indicated in Fig. 6, and the tool I5 is in a pattern and work piece, respectively, which is at corresponding position with respect to the work an angle of 45 degrees to the horizontal edge Ilia piece ID. as indicated by the arrow 91?) in Fig. 6. The system is energized by closing the switches When the tracer ?nger reaches a position hali 95, 96, and 91. Although the switches are illus way along the semicircular curve l3b, the Iorce trated as simple manually operated knife on the tracer ?nger represented by ‘the vector switches, it will be understood of course that tracer point 25!) will be withdrawn from the lon gitudinal edge l3a at the left of the pattern, as indicated in Fig. 6 which is an enlarged sche they may be remotely controlled electromagnetic 86c again increases to the value represented by the dashed line c’ in Fig. 8 which is the same contactors. When the tracer point 25b is in value of force that was exerted on the tracer the position illustrated in Fig. 6, no force is ex ?nger when it ?rst came into contact with the erted on the tracer ?nger. Since, when no force longitudinal edge 13a. As a result, at this point is exerted von the tracer finger. the output volt the tracer ?nger and the cutter are moved in a age 01' the cosine regulator is maximum and longitudinal direction with no component of the output of the sine regulator is zero, as indi transverse motion as indicated by the dotted cated in Fig. 5, the cross feed motor 10 which arrow Slain Fig. 6. is controlled by the cosine regulator will advance As the tracer ?nger 25b moves beyond the the tool toward the work piece and at the same midposition on the semicircular curve in Fig. 6, time advance the tracer ?nger toward the tem~ the force on the tracer ?nger is increased be plot at maximum speed, as indicated by the dotted arrow- associated with the tracer point 30 yond the value indicated by the vertical line 0' because the longitudinal feed motor 91 tends to 25b in Fig. 6. The output voltage of the sine keep forcing the tracer ?nger against the semi regulator being zero, the longitudinal feed m0 circular edge l3b and the speed of the cross feed tor 9| will be at rest and there will be no com motor is zero. But,“ as the force increases be ponent of longitudinal movement of the tool. yond the value indicated by the dashed line 0’, This relationship of the speeds of the cross feed the output voltage of the cosine regulator passes motor 10 and the longitudinal teed motor Si is through zero and the polarity of the voltage re indicated in Fig. 7. verses, with the result that the cross teed motor When the tracer point 25!) engages the edge ‘Hi rotates in the reverse direction to withdraw l3a oi the pattern, a force is exerted on the tracer ?nger and this force quickly builds up to 40 the tracer ?nger and the cutter. This reverse component of the cross feed mo the value indicated by the dashed line 0' in Fig. tion produced by the reverse rotation of the cross 8, and the magnitude of this force is also indi feed motor combined with the longitudinal com cated by the vector 95a in Fig. 6. As indicated ponent produced by the longitudinal feed motor in Fig. 8, when a force of this magnitude is apcauses the tracer and the cutter to follow a path plied to the tracer ?nger, the output oi! the cosine along the semicircular edge [3b between the po regulator decreases to zero and the output of the sitions indicated by the vectors 96c and 96d in sine regulator increases to a maximum, with the Fig. 6. result that the speed of the cross feed motor is At the 45-degree position represented by the decreased to zero and‘ the speed of the longi tudinal feed motor 9! is increased to maximum. 50 position of the vector 96d, the force on the tracer ?nger attains a value indicated by the magnitude This results in moving the tracer ?nger in a of the vector 96d which corresponds to the mag longitudinal direction with zero component of nitude‘ of the force indicated by the dashed line transverse motion as indicated by the dotted (1’ in Fig. 10, with the result that the cross feed arrow 91a. Simultaneously of course the cutter motor ‘Ill and the longitudinal feed motor SI I5 is moved along the work piece in the same operate at speeds represented by the intersec direction. tion of the dashed line (1' with the sine and cosine As the tracer point 25b begins .to move out of curves. In other words, the speeds of both mo engagement with the edge 13a of the pattern at tors will be equal and the cross feed motor ‘Ill the corner Hit), the force on the tracer ?nger decreases at a rapid rate with the result that 60 will be rotating in the reverse direction, i. e., the direction to withdraw the tracer ?nger and the speed of the cross feed motor 10 is rapidly the tool. The results of these two components increased to maximum and the speed of the will produce a resultant relative movement of longitudinal feed motor BI is rapidly decreased the tracer point and pattern indicated by the to zero. This causes the tracer point to advance dotted arrow 91d and will of course also produce inwardly along the semicircular edge lib oi’ the a corresponding relative movement between the pattern as illustrated by the dotted line 98 which cutter and the work piece. _ indicates the path of movement of the center of As the tracer point approaches the corner lid, the tracer point. The cutter is of course main the component of movement produced by the tained in a corresponding position with respect to the work piece. ' 70 cross feed motor can no longer relieve the force on the tracer ?nger, and consequently, this force As the tracer finger 25b is moved inwardly continues to increase until when it attains a along the semicircular curve Hi), the force on magnitude represented by the vector 96c and by I the tracer ?nger again increases linearly, there the position of the dashed line e' in Fig. 11, the by decreasing the speed of the cross teed motor ‘HI and increasing the speed of the longitudinal 75 speed of the longitudinal feed motor 9| is de 2,410,295 creased to zero and the speed or the ‘cross feed motor 10 is increased to a maximum in the re verse direction as indicated by the intersection of the dashed line c’ with the sine and cosine curves. As a result, the tracer point‘ and‘ the tool will be withdrawn at’maximum speed. . 14 “3 through suitable worm gearing III. This component of the relative movement of the cut ter and work piece represented by the vector V'c ‘ in Fig. 14 corresponds to the transverse compo nent of the relative movement produced by the cross teed motor ‘ID in the system of Fig. 1. However. as the tracer point tends to ride of! The table NH and the pattern supporting spin the edge of the templet at, the corner l3d, the dle I03 are driven in synchronism with each other force on the tracer-?nger decreases. rapidly to by means of an electric motor “5 to the drive the value indicated by the position of the dashed 10 shaft or which the table and the spindle are line 0' in Fig, 8,-with the result that the tracer respectively connected through suitable worm ?nger and cutter are moved in a longitudinal gearing Hi and worm gearing“ H ‘I which have .direction with no component of transverse mo! the same ratio. The component of relative move tion as indicated by the intersections of the ment between the cutter and the work piece pro dashed line 0' with the sine and cosine curves 50' 15 duced by the motor I I 5 and represented by the , and 5|’ in Fig. 8'. Thus, the relative movement of the cutter and work piece is controlled to follow a path corresponding to the contour of the pattern. . vector V'r. corresponds to the longitudinal~ com ponent of movement produced by the longitudi nal feed motor 9| in Fig. 1. - ~ The cross feed motor “3 and the longitudina Thus, the relative movement of the cutter 20 or rotary i'eed motor H5 are controlled by means , of electric valve apparatus (not shown) which responding to the- contour of the pattern. is identical with the electric valve apparatus of The constancy of the ‘magnitude of the veloc Fig. 1. In other words, the motors H3 and H5 ity V of the relative movement of the cutter replace the motors ‘l0 and 9|, respectively in the and workpiece for all cutting angles on the con 25 control system of Fig. 1. tour is illustrated in Fig. 12 and is explained I The operation or the apparatus of Fig. 13 when mathematically as follows: The relationship be translated into terms describing milling ma tween the sine and cosine functions of a variable chine operation instead of lathe operation is in quantity such as an angle is de?ned for all all material respects identical with the opera ‘values of the angle by the equation: _ 30 tion of the system of Fig. 1, and a repetition of and work piece is controlled to follow a path cor (1) sin=+cos’=1, or . ‘such operation is omitted. Although in accordance with the provisions (2) \/sin’+cos==1, which is a constant. of the patent statutes this invention is described Since the velocity of the longitudinal components as embodied in concrete form and the principle VL is always proportional to the sine function of 35 thereof ‘has been described, together with the the magnitude of the force F on the tracer ?n ger and the velocity of the transverse component V1‘ is always proportional to the cosine function of-the magnitude of the force F, therefore, (3) \/Vz.2+Vc==a constant, and since the re sultant velocity V=\/Vr.=‘+Vc’, therefore V equals a constant. best mode in which it is now contemplated. ‘ applying that principle, it will be understood that the apparatus shown and described is merely illustrative and that the invention is not limited 40 thereto, since ‘alterations and modi?cations will readily suggest themselves to vpersons skilled in the art without departing from the true spirit In other words, the velocity V of the relative movement of the cutter and work piece is con stant for all angles'oi such movement along the path of the contour of the work piece. In Fig, 13 which illustrates an application of the invention to a polar .co-ordinate type milling a movable element having an initial position, a machine, the work piece I00, which is illustrated pair of members, a separate driving means for of this invention or from the scope of the annexed claims. ‘ 'What we claim as new and desire to secure" by Letters Patent of the United States is: 1. A control system comprising in combination, as a cam, is mounted on a rotating tablellll 50 each or said . members and means responsive The milling cutter Hi4 together with its driving to a continuously increasing displacement of said element from said initial position for producing a linearly varying voltage, means for deriving motor I05 are mounted on a head I06 which, in from said voltage two inversely varying control and the pattern H12 is secured to a frustum ' shaped spindle £03. turn, is slidably mounted in ways lli‘la built in 55 voltages, means responsive to one or said in versely varying voltages for energizing one of the crossrail 181. In many types of milling ma chines, the cross rail is slidably mounted on up— rights to provide for elevation, but in the simple milling machine illustrated, the crossrail is ?xed ly secured to an upright I08 which preferably is formed integral with the bedplate [09. The tra said driving means to eiIect a component of rela tive movement of said members with a velocity that varies continuously from a maximum value in one direction to a maximum value in the reverse direction and means responsive to_the cer ?nger H0 is ?xedly mounted on- the crossrail I01, and a manually rotatable lead screw Ill serves to position the head I06 along the ways other of said inversely varying voltages for ener gizing the other of said driving means to- effect to provide for initial adjustment of the distance between the milling cutter and'the tracer ?nger. The table _|lll and spindle I03 are rotatably mounted on a platen I H which is slidably mount- _ ed on the slide I091: with which the bedplate I09 ' is provided. “ an angularly displaced‘ component of relative movement of said members ‘with a velocity that e ‘ varies continuously from a minimum value to a ‘maximum value and from said maximum value to a minimum value. , . 2. A control system comprising in combina 70 tion. a movable element having an initial posi- ~ Movement of the platen in ‘together with the rotating table l_0l which supports the work piece _tion, a pair of members, means responsive to a and the spindle I03 which supports the pattern 7 .is e?ected by means of a lead screw (not shown) ‘ment from said initial position for producing a continuously increasing displacement of said ele voltage that varies substantially linearly with said which is driven by means or an electric motor 76 displacement, electric ‘valve means ior deriving 2,410,295 15 y from said voltage a ?rst control voltage that 16 varies from a positive maximum to a negative maximum and a, second control voltage that simultaneously varies from a minimum value to a maximum value and from said last mentioned maximum value to a minimum value, and driv ing means responsive to said ?rst and second force to said element, means responsive to the resulting change in permeability of said element for producing a continuously variable voltage, means for deriving from said variable voltage two inversely varying control voltages and means re sponsive to said inversely varying voltages for effecting operation of said driving means at in control voltages for effecting relative movement versely varying speeds. ' 6. A control system comprising in combina of said members with a velocity having a com‘ ponent that varies from a maximum value in one 10 tion, a magnetostrictive control element, a pair direction to a maximum value in the reverse of electric motors, means for applying a variable direction and an angularly displaced inversely ‘force to said element, means responsive to the varying component, 3. A control system comprising in combination, a movable control element having an initial posi tion, a, pair of driving means and means respon~~ sive to a continuous displacement of said control resulting change in permeability of said element for producing a continuously variable control 15 voltage, means for deriving from said voltage two element from said initial position for producing a voltage which varies approximately linearly with said force, means responsive to said voltage for producing a first control voltage which varies from a positive maximum to a negative maxi mum, and a second control voltage that varies simultaneously from a minimum value to a maxi continuously and inversely varying control volt ages, and means controlled by said inversely varying voltages for operation of said motors at speeds that vary inversely with respect to each other as said force is continuously varied. 7. A control system comprising in combina tion, a magnetostrictive control element, a pair of electric motors, means for applying a variable force to said element, means responsive to the mum value and from said last mentioned maxi 25 resulting change in permeability of said element mum value to a minimum value, means responé for producing a direct control voltage that varies sive to said ?rst control voltage for energizing substantially linearly as said force varies, means one of said driving means to operate at a speed for deriving from said voltage a ?rst control that varies continuously from a maximum value voltage that varies continuously from a maximum in one direction to a maximum value in the re 30 value of one polarity to amaximum value of the verse direction and means responsive to said opposite polarity and a second control voltage of ?xed polarity that varies inversely in magnitude with respect to said ?rst control voltage, and speed that varies inversely with the speed of said means controlled by said derived ?rst control first driving means. ‘ 35 voltage for effecting operation of one of said motors at a speed that varies continuously from 4. A control system comprising in combination, second voltage for energizing the other of said driving means to operate in one direction at a a magnetostrictive control element, a pair of driving means, means for applying a force to said a maximum value in one direction to a maximum value in the other direction. ' 8. A control system comprising in combina element, and means responsive to the resulting change in permeability of said element for pro 40 tion, a magnetostrictive control element, a pair ducing a voltage that varies approximately of electric motors, means for applying a force to said magnetostrictive element, means respon linearly with said force, and electric valve means sive to the resulting change in permeability of for deriving from said voltage a ?rst control voltage that varies continuously from a positive said element for producing a voltage that varies '' continuously as said force varies, electric valve maximum value to a negative maximum value means for deriving from said voltage a ?rst con and a second control voltage that simultaneously trol voltage that varies continuously from a maxi varies from a minimum value to a maximum mum value of one polarity to a maximum value value and from said last mentioned maximum of the opposite polarity and a second control value to a minimum value, and means respon voltage of unchanging polarity that varies in~ sive‘to said control voltages for effecting opera versely in magnitude with respect to said ?rst tion 01' one of said driving means at a speed that varies continuously from a maximum value in one direction to a maximum value in the reverse . direction and simultaneous operation of the other of said driving means in one direction at a speed that varies inversely with respect to the speed of said ?rst driving means as said force is continuously varied. 5. A control system comprising in combina tion, a 'magnetostrlctive control element, a pair 60 of driving means, means for applying a variable I derived control voltage as said force varies con tinuously, and means individually responsive to each of said derived control voltages for effect ing operation of each of said motors correspond ing in speed and direction to the magnitude and polarity respectively of a diilerent one of said derived control voltages. HANS P. KUEHNI. NORMAN G. BRANSON.