US3528337A

US3528337A - Tracing machine

Info

Publication number: US3528337A
Application number: US737669A
Authority: US
Inventors: David H Dulebohn
Original assignee: Oerlikon Italiana SpA; Andrew Engineering Co
Current assignee: Oerlikon Italiana SpA; Andrew Engineering Co
Priority date: 1968-06-17
Filing date: 1968-06-17
Publication date: 1970-09-15
Anticipated expiration: 1987-09-15
Also published as: GB1265703A; FR2011076B1; JPS4926549B1; DE1929925A1; DE1929925B2; FR2011076A1; DE1929925C3

Description

United States Patent [72] Inventor David .Dulebohn Minneapolis, Minnesota [21] Appl. No. 737,669 [22] Filed June 17, 1968 [45] Patented Sept. 15, 1970 By direct and mesne assignments of one-half to Andrew Engineering Company Minneapolis, Minnesota a corporation of Minnesota, and one-half to Oerlikon ltaliana SIpA, Milan, Italy,

a corporation of Italy [73] Assignee [54] TRACING MACHINE 14 Claims, 17 Drawing Figs. [52] U.S.Cl 90/l3.7, 90/62, 250/202 [51] Int. Cl. B23q 35/128 [50] Field of Search 90/13, 13.6, 13.7, 13.9. 13,99,62, 11.4, 11.42, 11.44, 11.5, 11.52, 11.6, 11.62; 250/202 [56] References Cited UNITED STATES PATENTS 2,853,626 9/1958 Wetzel 250/202 2,882,476 4/1959 Wetzel 90/13X 2,989,639 6/1961 Dulebohn et al. 90/ l 3.5X 3,105,907 10/1963 Colten et al. 250/202 Primary Examiner-Gerald A. Dost Attorney-Williamson and Palmatier and Bains ABSTRACT: A tracing machine and control system interchangeably moving a cylindrical or flat workpiece relative to a tool under the control of a line drawing lying in a plane, and over which a sensing head travels parallel to the plane.

Patented Sept. 15, 1970 v 3,528,337

. INVENTOR.

DAV/D DMCEBO/ /A/ fiM-W, Mar -m Patented Sept. 15, 1970 Sheet Qm ul QMQ QMMWR QMW W Qmv Patented Sept. 15, 1970 Sheet FIG. 9

INVENTOR. JAV/D A ZULEEM A/ Patented Sept. 15, 1970 3,528,337

Sheet 5 of? FIG. IO

INVENTOR.

Patented Sept. 15, 1970 Sheet IINVENTOR. 24W) H 21/166 50/740 ATTOEA EFJ TRACING MACHINE This invention is related to that disclosed and claimed in copending application entitled Tracing Machine filed February 27, 1967, Ser. No. 618,835, now US. Pat. No. 3,493,762. The only important known prior art is US. Pat.

An object of my invention is the provision of a new and improved control apparatus effecting relative movement between a tool and a workpiece with a predominantly curved face to be worked by the tool.

Another object of my invention is to provide a novel control apparatus utilizing a line drawing which is simply traced or followed to effect the desired relative movement between a tool and the predominantly curved workpiece upon which the tool acts to produce a configuration corresponding to that of the line drawing.

Still another object of my invention is the provision of an improved and novel control apparatus sensing a line drawing laid on a flat support and effecting the necessary relative movement between a tool and a workpiece having a predominantly curved or annular face upon which the desired configuration is produced, identical in shape and identical in proportion or size to that of the line drawing.

A further object of my invention is to provide a new and novel control apparatus sensing a line drawing laid flat on a plane table and effecting the necessary relative movement, linear or rotational, interchangeably, between a tool and a workpiece, and thereby provide for producing a configuration on either a planar workpiece or one with a predominantly curved or annular face.

A still further object of my invention is to provide a control apparatus sensing a line drawing laid flat on a plane table, and effecting both rotational and linear movement between the tool and a predominantly curved workpiece, to produce the configuration of the drawing on the workpiece face.

These and other objects and advantages of my invention will more fully appear from the following description made in connection with accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the several views, and in which:

FIG. 1 is a perspective view illustrating the tracer and vertical milling machine controlled thereby;

FIG. 2 is a diagrammatic sketch of the principal functional components in the tracer;

FIG. 3 is a diagrammatic sketch of the line viewing and sensing apparatus;

FIG. 4 is a schematic sketch of the control apparatus associated with the X-axis lead screw in the tracer;

FIG. 5 is a schematic sketch of the control apparatus associated with the Y-axis lead screw in the tracer;

FIG. 6 is a diagrammatic sketch of control and operating apparatus associated with the X-axis lead screw in the slave or milling machine;

FIG. 7 is a schematic sketch of the operating and control apparatus associated with the Y-axis lead screw of the slave milling machine;

FIG. 8 is a diagrammatic sketch of the control and operating apparatus associated with the rotatably mounted workpiece;

FIG. 9 is a section view of the feed back drive sensing the rotary movement of the workpiece, and taken approximately at the broken line indicated at 99 in FIG. 10;

FIG. 10 is a section view taken approximately at 10-10 in FIG. 9;

FIG. 11 is an enlarged detail view of the sensing disc and its relation to the feed back disc and is somewhat distorted for purposes of illustration;

FIG. 12 is a diagrammatic view and block diagram illustrating the various modes of operation; and

FIGS. 13, 14, 15, 16 and 17 are diagrammatic views, somewhat distorted, for illustrating certain modes of operation.

One form of the invention is illustrated in the drawings and is described herein. The tracer is indicated in general by numeral 10, and the slave machine, in this instance a vertical milling machine, is indicated in general by numeral 11. The tracer is very similar in most respects to the tracer described in applicant's said copending application Ser. No. 618,835. Principal aspects of the tracer 10 are described and illustrated herein and other details have been omitted herein.

TRACER The tracer 10 carries a drawing 12 on which a line 13 appears. The drawing 12 is laid flat, or in a plane, and is attached as by tape to a flat rigid panel 14 constructed of smooth light transmitting material such as glass. The upper and lower edges of the panel 14 are straight and parallel, and mount and guide the mounting wheels of a carriage 15 movable in the X-axis direction indicated by arrows X and under the influence of the X-axis lead screw 16, which is journalled at its opposite ends in bearings attached to the panel 14. The carriage 15 has a follower or nut on the lead screw 16 to effect linear movement of the carriage as the lead screw 16 is revolved.

The carriage 15 slidably mounts a line following head 17 slidably mounted in the Y-axis direction as indicated by the arrows Y and under the influence of the Y-axis lead screw 18, the opposite ends of which are journalled in bearings on the carriage 15 adjacent the upper and lower edges of the panel 14. As illustrated in FIGS. 4 and 5, the X-axis and Y-axis lead screws are operated by

servo motors

19 and 20, respectively, and the

lead screws

16 and 18 are also drivably connected to the rotors of

synchro control transmitters

21 and 22, which are commonly referred to as simply synchros. The line following head 17 transmits a small segment of the line 13 under a high degree of illumination, through a coherent fiber optics bundle 23 and directs the image into the rotary image sensing head 24 in the tracer. The image I as indicated in FIG. 3 is cast into the rotary head wherein an image divider 25 has a knife edge 25aon the rotation axis of head 24, see FIG. 2, and between reflecting surfaces 2511 so that the segment 13'of the line in the image I is reflected to the photocells 26 and 27 which are alternately operable, depending upon the direction of travel of the head 17 along the line 13. The photocells 26 and 27 are divided so that when the segment 13' of the line moves to one side or the other, the halves of the divided photocell will unbalance a bridge circuit and cause the reversible motor 28 to revolve in one direction or another and thereby turn the head 24 through the timing belt 28a and return the photocell into balanced position with respect to the segment 13' in the image I. The turning of the head 24 to a new orientation necessitates a readjustment of the rotation speeds of the X- and Y-

axis lead screws

16 and 18 to enable the head 17 to follow the line in the changed direction.

In this regard, the head 24 carries an eccentric 29 on which circular discs 30 and 31 are mounted. The discs 30 and 31 respectively operate the X-axis and Y-

axis control mechanisms

32 and 33 of the tracer. A substantially continuously operating variable speed motor 34 drives the

ball disc integrators

35 and 36 by means of

timing belts

34a and 34b so that the input to both integrators is the same, the output of which is at rotary gears 35a and 36a.The speed and direction of the integrator outputs relate directly to the linear positions of control slides 37 and 38, respectively, which bear against the discs 30 and 31. Thus, as the-head 24 changes its orientation under influence of motor 28, the rotational speed and direction of output gears 35a and 36a are changed.

In the X-axis control apparatus 32, gear 35a is meshed with and drives into a train of gears 39a-39g. Gears 39a and 39b are identical in size, and the remainder of the gears in the train are of 'various sizes to produce various speed ratios. The speed ratio between gears 39a and 39g, the smallest and largest, is 10 to 1 as illustrated. Of course, other ratios such as 20 to I might be used.

Similarly, the Y-axis control apparatus 33 includes a train of gears 40a40g wherein gears 40a and 40b are identical in size, and the size of the remainder gears varies to obtain various speed ratios identical to the speed ratios in the other gear train.

The several gears 39a-39g are drivably connected on the rotors of synchro transformers 4la-41g, and, similarly, the gears 40a40g are drivably connected to the rotors of synchro transformers 42a42g.

As indicated in FIGS. 4 and 5, the synchro 41a is connected through an amplifier 43 to servo motor 19 of the tracer X-axis lead screw, the turning of which is sensed by the synchro 21 providing feed back to the synchro 41a; and similarly, the synchro 42a is connected through amplifier 44 to the servo motor 20 of the tracer Y-axis lead screw 18, the turning of which is sensed by synchro 22 to provide feed back to the synchro 4211. Simply by turning gears 39a and 40a from the output of

integrators

35 and 36, the necessary unbalance is created by revolving the rotors of synchros 41a and 42a as to cause servo motors l9 and 20 to revolve the lead screws.

The remainder of the synchros 41b41g and 42b42g provide for moving the workpiece W in the slave milling machine 11.

CUTTER OFFSET OR COMPENSATION The tracer also incorporates a cutter offset control apparatus 45 including a rotor 46 turned under influence of timing belt 28a and motor 28 simultaneously with the rotary head 24 for maintaining the adjustable eccentric 47 at a predeter mined angular orientation with respect to the axis of rotors 24 and 46 and thus in relation to the outputs of the X-axis and Y-

axis control mechanisms

32 and 33. The eccentric 47 is mounted on a slide 470 which is adjustable across a diameter of rotor 46, and, of course, when the eccentric 47 is on the rotation axis of rotor 46, there is no eccentric movement. The eccentric 47 has

circular operating discs

48 and 49 to move slides 50 and 51, respectively, and cause turning through rack and pinion drives, of synchro

differential transmitters

52 and 53, respectively. The

synchros

52 and 53, as hereinafter more fully described, simply keep the tool in the slave machine off to one side of the line of trace by an amount which may in some instances approximate half the diameter of the cutting tool.

SLAVE MACHINE The slave milling machine has a base and column structure 54 on which the saddle-mounting knee 55 is vertically adjustable. The ram and turret assembly 56 carries the spindle head assembly 57 which includes the drive motor for turning the spindle 57a which mounts the tool or cutter 58. The tool or cutter 58 is generally tapered, as illustrated in FIG. 14, or may be straight-sided as illustrated in FIG. 13. The saddle 60 is slidable on the knee 55 in a fore and aft direction indicated by arrow Y. The workpiece mounting table 61 is mounted on the saddle 60 for side to side movement in the direction of arrows X. Movement of the table 61 in the X-axis direction is produced by operating servo motor 62 which rotates the X- CYLINDRICAL WORKPIECE MOUNTING AND ROTATION Means are provided on the table 61 for mounting the cylin drical workpiece W and producing carefully controlled rotation thereof. One end of the workpiece W is mounted on a dead center 68 carried on a conventional mounting structure 68a, and the other end of the workpiece W is affixed to a shaft 69 of very considerable size. The shaft 69 is mounted in suitable bearings on the table 61 and contained within the control housing 70. The rotation axis 71 of the workpiece W and shaft 69 lies parallel to the X-axis lead screw 63 which extends in the direction of arrows X. 50 as to understand the relationship, the rotation axis 71' of the workpiece W and shaft 69 will in many modes of operation be intersected by the rotation axis of spindle 57a and tool 58', and in other modes of operation, the vertical axis of the spindle and tool 58 will lie parallel to but spaced slightly from a vertical plane containing the rotation axis of the workpiece W and shaft 69. An extension of shaft 69 also concentrically mounts a rigid feed back disc or circular template 71 which is circular or cylindrical in shape and is of a size identical to the size of the cylindrical workpiece W. The workpiece W is rotated in either direction as indicated by arrow R by a servo motor 72 driving through a speed reducing mechanism 72c and by a drive gear 72b which is affixed concentrically to the shaft 69. The speed reducing gearing mechanism necessarily has a minimum of backlash or play so that the workpiece is very accurately controlled as to rotary position.

A synchro 73 detects the rotary movement of the workpiece W and is revolved through a step up train of the gears including gears Ma-74d, and a sensing disc or measuring wheel 75 which is substantially smaller than the feed back disc 71 and bears against the edge thereof with a considerable amount of pressure. The physical arrangement of this rotation sensing and feed back structure is illustrated in FIGS. 9-11. A base plate 76a is mounted rigid with the workpiece supporting table 61 and is slotted to adjustably mount a slide plate 76b which will be adjusted to accommodate feed back disc 71 of various sizes as various sizes of workpieces W are employed in the slave machine 11. The slide 7 6b is normally affixed to the base 76a by clamp bolts 76b.

Mounting plate 76c is affixed to the slide 76b by clamp screws 76c, and confine a very thin shim 760", the purpose of which will hereinafter more fully be described.

A swingable mounting assembly 77 carries the disc 75 and the associated gear train 74a-74d to facilitate moving the disc 75 against the feed back disc 71 with a considerable amount of pressure. The assembly 77 includes a base plate 77a to which the synchro and bearing mounting plates 77b and 770 and spacers 77d are affixed as by screws 77b and 77c. A pivot pin 78 extends through bearing apertures in the mounting plate 76c and through the plates 77a, 77b and 77c. One end of the pin 78 carries a screw and washer'assembly 78a to bear against the mounting plate 76c, and the other end of the pin 78 has a retaining cap 78b confining a coil spring 78c and bearing against the assembly 77 to hold it tightly against the mounting plate 76c.

Adjacent the opposite ends of the swingable assembly 77, a similar pin 79 extends through aperatures in the several plates of the assembly 77 and through an elongated slot 79a in the mounting plate 76c to facilitate limited movement of the assembly 77 in the direction of arrows A as seen in FIG. 10. Pin 79 has a similar screw and washer assembly 79b at one end, and a retaining cap 79c at the other end confining a coil spring 79d against the top plate 77c to hold the assembly 77 tightly against the mounting plate 76c.

An car 80 is affixed to the edge of the mounting plate 76c and carries a screw 80a which rotates and slides freely in an aperture 80b. The screw 80a is threaded into a tapped hole in the edge of the swinging plate 770; and a coil spring 80c surrounds the screw 80a and bears against the car 80 and against the edge of the plate 77a for urging the swinging assembly 77 toward the disc 71. The spring 80c applies the desired pressure between the

discs

75 and 71, and the screw 80a is utilized to pull'the swinging assembly 77 and disc 75 slightly away from disc 71 so as to relieve the pressure when sliding adjustment as to position is to be made, when the feedback disc 71 is changed.

With respect to FIG. 11, it will be noted that the feed back disc 71 has a peripheral edge 71a which is truly cylindrical. However, the sensing disc 75 has a peripheral surface 75a which is circular about the axis 75' of the disc, but is not cylindrical because the peripheral surface 75 is arched or curved. The degree of arch or curvature is somewhat exaggerated in FIG. 11 so as to be clearly visible, but it is important to note that the surface 75a has somewhat different diameters at various locations across the width thereof. For instance, the diameter of the surface 75a is considerably less adjacent the edges of the peripheral surface 75a than at the location midway between the edges. In view of the high degree of precision with which this feed back or motion sensing apparatus is to operate, it is desired that the rotor of the synchro 73 be turned precisely one revolution whenever the disc 75 rolls a distance of 0.100 inches along the periphery of feed back disc 71. In order to very precisely obtain this relationship, the rotation axis 75' of the disc 75 may be oriented very slightly obliquely of the rotation axis 71' of the feed back disc and workpiece, by inserting the shim 76c" between the slide 76b and the mounting plate 76c. This causes the peripheral surface 750 of the disc 75 to engage and roll on the feed back disc 71 along a path or course 75b as indicated by the dot dash line in FIG. 11 at which location the diameter of the peripheral surface 75a is precisely that which gives the proper relationship between the feed back disc 71 and the synchro 73. The changing of the amount of shim at 76c" essentially causes a slight tilting of the disc 75 in the direction indicated by arrows T as shown in FIG. 11. When the position of disc 75 is once established through use of the shim 76 the disc will not be readjusted again in this manner.

OPERATION AND SWITCHING With reference to FIGS. 48 and 12, a completion of the synchro and servo motor circuits must be understood in order to understand the operational advantages of the invention. The X- and Y-

axis control mechanisms

32 and 33 of the tracer are always connected in controlling relation to the X- and Y- axis lead screws 16 and 18 respectively of the tracer through the corresponding synchros 41a and 42a.

Of the remainder of the synchros 41b41g, only one of these synchros is operative at any one time, depending upon the position of the ganged selector switches 81a and 8112. Similarly, only one of the synchros 42b-42g is operative at any one time, depending upon the position of the ganged selector switches 81c and 81d which are also connected and operated simultaneously with the ganged selector switches 81a, 81b, in order that both the X-axis and Y-

axis control mechanisms

32 and 33 are operating at the same reduction or multiplication ratios. The ganged selector switches are placed at; ssibs t b s snq g i fi a i s th drawing 12 and the workpiece W. Ordinarily, it is desirable to utilize as large a ratio as possible, and therefore the line following head 17 will have to move a substantial distance along the line 13 in order to produce a rather small movement between the tool 58 and the workpiece W; and if the drawing is ten times the size of the configuration to be produced on the workpiece, synchros 41g and 42g will be connected into the circuit for controlling the slave milling machine 11. The advantage in working with as large a drawing 12 as possible relates to the minimizing of any possible error. For example, if the drawing is ten times the size of the configuration produced on the workpiece, any error in the drawing (as to line location, radius of curvature, etc.) is reduced by a factor of ten before the error is repeated on the face of the workpiece. On the other hand, if the drawing were to be the identical size of the actual configuration being produced on the workpiece, any error occurring in the drawing is repeated on the face of the workpiece without any reduction as to magnitude.

However, for purposes of illustration in FIG. 12, it is assumed that the drawing and the configuration on the workpiece are on a one to one ratio, and therefore it is assumed for purposes of the explanation that synchros 41b and 42b are utilized for producing the control output of the X-axis and Y-

axis control mechanisms

32 and 33.

Although the connections to the several servo motors and the corresponding synchros on the slave machine may be effected through a number of modes of switching, FIG. 12 illustrates diagrammatically various connections that may be accomplished through switching. The switching is indicated in general by numeral 82. The switching 82 indicates, at the right, the connections to the control and operating loops of the

servo motors

62, 64 and 72. The outputs from the X-axis and Y-

axis control apparatus

32 and 33 are brought into the switching 82 and may be connected by the several switches 82a, 82b, and 82c into any of the loops of

servo motors

62, 64 or 72. Likewise, the outputs from the X-axis and Y-axis cutter offset (c/o) synchros 52 and 53 are brought into the switching 82 and may be connected by the

switches

82d, 822 and 82f into any of the loops of

servo motors

62, 64 or 72.

SPECIFIC MODES OF OPERATION Five specific modes of operation are hereinafter described. The reasons for and advantages in each mode of operation are included with each mode explanation. From the operation standpoint, Mode I is basic, and the remaining Modes II through V emphasize the functional advantages and distinctions of the present invention.

OPERATION MODE I In this most elemental mode of operation, the controls provided allow the use of a flat surfaced workpiece on the table 61, and then by simply utilizing the output control mechanisms for the control of the X- and Y-axis lead screws 63 and 65 in the milling machine 11, production of a desired configuration corresponding to the shape of a line on the tracer can be obtained on the flat workpiece.

It is to be noted that flat surfaces on the otherwise cylindrical workpiece W can be machined in an identical manner, thus enabling production of a desired configuration corresponding to the shape of a line on a drawing, and also enabling altering from machining flat surfaces to machining cylindrical surfaces on the same workpiece by switching to modes of operation subsequently described.

In order to accommodate flat surfaced workpieces, the X- axis and Y-axis outputs from the synchros 41b and 42b in

control mechanisms

32 and 33 are connected to the control loops of

servo motors

62 and 64. In addition, the cutter offset synchros are connected in series in these loops so that desired degree of cutter offset is added to the movement of the slave milling machine by offsetting the eccentric 47 (FIG. 2).

Mode I is established by appropriate settings of switches 82 in FIG. 12 as follows: 82aposition X, 82bposition Y, 82cposition OFF, 82d-position X, 82e-position Y, 82fposition OFF.

OPERATION MODE II This mode of operation is illustrative of certain aspects of the invention and one purpose of this mode is to produce a groove in a cylindrical workpiece. The depth of the groove will ordinarily be manually controlled by precision controls on the vertical milling machine 11 which move the spindle 57a upwardly and downwardly. It should be also noted that the line following head 17 of the tracer may be made to move forth and back along the line 13 to produce repeated traveling of the workpiece under the tool by simply switching the photocells and related circuitry from forward to reverse. This is of particular advantage after the initial groove has been machined at which time the work is offset so as to remove material from first one side and then the opposite side of the groove as is frequently done in finishing or establishing the final width of the groove.

The drawing, with the configuration to be developed on the workpiece W, is laid flat on the tracer. The switching 82 is adjusted so that movement of line following head 17 in the X- axis direction produces movement of workpiece W in the X- axis direction; and movement of the head in the Y-axis direction produces rotation of workpiece W. The switching 82 is adjusted as follows: 82a-position X; 82b-position OFF; 82cp0siti0n Y; 82dposition X; 82eposition OFF; 82fposition Y.

After rough cutting the groove, adjustment of eccentric 47 produces operation of cutter offset

synchros

52 and 53 which adds motion to servo

motors

62 and 72. The workpiece is thereby moved in the X-axis direction, and is revolved with a slightly greater magnitude than is indicated by the drawing so as to widen the groove. The increment of added motion in the rotary direction R is indicated at in FIG. 17.

Another purpose for this mode of operation is illustrated in FIG. wherein the cylinder is machined so as to leave a raised rib on the cylindrical surface. In this case, the Y-axis cutter offset synchro 53 movement is used to rotate the rib away from the cutter so that the rib W is allowed to remain on the surface of the cylinder. Of course, the X-axis cutter offset synchro 52 also produces added movement in the X-axis direction. As will be explained hereinafter, this method of machining to produce a raised rib has certain disadvantages; however, one advantage is that the resulting peripheral surface W" of the workpiece W is nearly circular.

The eccentricity of eccentric 47 is adjusted so that the workpiece W is displaced by one-half the width of the outer face F of the rib plus one-half the tool diameter adjacent the edge E of face F. This displacement results in added movement along the )(--axis and rotation in the direction R through the arc 0".

OPERATION MODE III This mode is established for two purposes: One is to machine a groove in a cylinder wherein the sides are parallel as illustrated in FIG. l3, and the other purpose is to machine a raised rib on a cylindrical surface wherein the width D of face F on the rib W must be held constant as illustrated in FIG. 14.

Neither of the two above described machining operations can be performed by Mode II of operation. In Mode II the first machined groove is made wider by adding to the rotation of the workpiece W as shown in FIG. 17. As illustrated in FIG.

17a, the sides of the groove so produced are not parallel, and even if the tool were cylindrical (not tapered), the sides of the groove would not be parallel. As is hereinafter explained, Mode III is established to cut the sides of the groove parallel as shown in FIG. 13.

Similarly, a problem is encountered when material is being cut away on the workpiece so as to form a rib W of predetermined height and with the outer face having a predetermined width D. Assuming that the dimension D is to be .002 inches, and further assuming that the rib W is shaped somewhat like a snake with portions thereof extending directly on a circumference of the workpiece W and other portions thereof lying parallel to the rotation axis, and in order that the rib derives strength from its triangular shape, it is necessary to form the rib W with a tapered cutter, substantially as illustrated. If the cutter offset correction is to be introduced as a result of setting adjustment 46a to move the table 61 in the direction X (FIG. 14) under influence of synchro 52 and if the cutter offset correction, introduced by the synchro 53, is affected by rotating the workpiece in the direction of arrow R as in FIG. 5, the portions of the rib W extending along a circumference of the workpiece W (where the entire cutter offset correction is effected through operation of the X-axis lead screw 63), as illustrated in FIG. 14, the top face F of the rib W will have the desired dimension D such as .002 inches. However, in the portion of the rib W (FIG. 15) which lies parallel to the rotation axis 71 of the workpiece W (along which the entire cutter offset is provided under the influence of synchro 53 by rotating the workpiece W), the width of the face F of the rib W will be substantially widened, and may be half again as much as dimension D, or more than .003 inches. This broadening of the outer face F of the rib W occurs where the cutter offset is provided by revolving the workpiece W because, as the edge E of the outer face F of the rib is being formed along a circumference of the workpiece as shown in FIG. 14, the tool is engaging edge E at one longitudinal position along the length of the tapered cutter 58 at which location the cutter has a diameter d. Another location along the length of the tapered cutter 58 (which has a smaller diameter d because of the tapered shape of the tool 58) is utilized for defining the edge E of the rib W along a portion of the rib seen in FIG. 15 lying parallel to the rotation axis 71'. These two locations along the length of cutter are spaced from each other by distance d". As the cut is being made parallel to the rotation axis, the portion of the tool 58 doing the cutting has a diameter d which is less than the diameter d and simply doesnt cut away as much stock and therefore the width D of the face F of the rib W is increased.

Further, as illustrated in FIGS. 14 and IS, the triangular or trapezoidal shape of the rib W will also vary if the cutter offset is provided by rotating the workpiece in response to synchro 53. As the rib W extends parallel to the axis 71', the width of the base of the rib W is reduced, while the width D of the face F increases in excess of the desired size.

Mode III overcomes these difficulties by application of the cutter offset correction from the Y-axis synchro 53 to the Y- axis lead screw 65 in the slave milling machine while the principal control of workpiece W from the Y-axis control mechanism 33 and specifically synchro 42b, is applied to the motor 72 for revolving the workpiece. Both the primary X- axis control synchro 41b of the X-axis control mechanism 32 and the X-axis cutter offset control synchro 52 are connected into the operating and control loop for the X-axis servo motor 62 and lead screw 63 of the milling machine 11, and this relationship is established in the switching 82 of FIG. 12 by maintaining the switch 82a at the X position, and moving the cutter offset switch 82d to the X position also.

In this condition the only active control applied to the Y axis lead screw 65 of the milling machine 11 is the synchro 53 which introduces the linear motion (0 FIG. 16 and 0" FIG. 13), and this synchro 53 is essentially connected directly across the terminals Y in FIG. 7 to complete the operating and control loop for the servo motors 64. Mode III is established by appropriate settings of switches 82 as follows: 82a-positi on X, 82b-position OFF, 82cposition Y, 82dposition X, 82eposition Y, SZf-position OFF.

In this mode the Y-axis control mechanism 33 is connected to the terminals T directly across the terminals R of FIG. 8 to apply the control influence to synchro 42b for controlling the rotary movement of workpiece W to the operating and control loop of the servo motor 72.

Insofar as the tool 58 and the workpiece W have relative movement in the X-axis direction, the operation of the slave machine is identical to that previously described.

Movement of the line following head 17 in the Y direction on the tracer produces, through operation of Y-axis control mechanism 33, revolving of the workpiece W through operation of the servo motor 72 under influence of synchros 42b and 73; and motion is also added to the workpiece W by moving the workpiece linearly under influence of the Y-axis lead screw 65 of the slave machine under the control of the cutter offset synchro 53. It should be understood that the magnitude of linear movement through operation of the Y-axis lead screw 65 is rather small, but it is significant from the standpoint of producing an extremely accurate cutting of the workpiece. The rotation axis 71 of the workpiece is moved into spaced relation with a vertical plane including the rotation axis 580 of the tool 58, and this magnitude of the cutter offset is indicated by the dimension 0 in FIG. 16 and in this instance may'approximate one-half the tool diameter (.125 inches) at the height of the edge E, plus one-half the width D .002 inches, such that the dimension 0' may have a typical magnitude of .063 inches. In the case of the formation of a groove with parallel confronting sides as indicated in FIG. 13, the groove may be rough cut and then finished with the same tool, in which case the magnitude of cutter offset will be the amount by which the groove is widened in finishing, such as the dimension which may be in the order of .001 inches; and the movement 0" of the workpiece W is produced by Y- axis lead screw 65 in making this finish cut.

It will be understood that most of the time the relationship between the workpiece W and the tool 58 is influenced by both the cutter offset

synchros

52 and 53, but the extreme situation is most illustrative of the importance of the correction provided by the Y-axis cutter offset synchro controlling the Y-axis lead screw 65 of the slave machine when the direction of cutting is parallel to the rotation axis of the workpiece W.

OPERATION MODE IV This mode is established to control the rotary motion of the workpiece W by the X-axis motion of the tracer mechanism 32. As previously indicated, reorientation of the related axes of the tracer and slave milling machine facilitates working on larger diameter workpieces. This mode is especially useful when work must be performed such as machining a variable pitch thread groove around the cylinder which requires that the cylindrical workpiece W turn in one direction many revolutions.

Mode IV is identical to Mode ll except the axes are crossoriented so that motion in the X-axis direction of the tracer and rrechanism 32 controls the rotary motion in the slave milling machine; and the motion in the Y-axis direction in the tracer and mechanism 33 controls the motion of the slave milling machine in the direction X.

,Mode IV is established by appropriate settings of switches 82 as follows: 82aposition Y, 82b-position OFF, 820- position X, BZd-position Y, 82eposition OFF, 82f- -position X.

OPERATION MODE V This mode is established to duplicate the operation of Mode Ill except that control between the relative axes of the tracer and slave is reoriented so that the X-axis tracer mechanism 32 controls the rotary motion of the workpiece W in the slave milling machine, the Y-axis motion in the tracer, and mechanism 33 controls the X-axis movement of the slave, and the signals from the X-axis cutter offset synchro 52 control the movement of the Y-axis slave lead screw 65 so cutter offset is introduced as straight line movement as shown in FIG. 16, O Mode V is established by appropriate settings of switches 82 as follows: 82aposition Y, 82bposition OFF, 82c position X, 82dposition Y, 82e-position X, 82fposition 055;.

It will be seen that I have provided a new and improved control and operating apparatus for moving a cylindrical workpiece under influence of a line drawing laid flat on the tracer, and wherein the cylindrical workpiece may be moved linearly in transverse directions and may be also rotated in order to produce the desired configuration on the cylindrical surface thereof, identical to the configuration of the line in the drawing.

Of course, it will be understood that various changes may be made in the form, details, arrangement and proportions of the various parts without departing from the scope of my invention.

I claim:

1. Operating and control apparatus producing relative motion between a tool and a workpiece with a curved face, comprising:

operating means producing relative motion between the tool and workpiece in the curved direction of said face and in a second direction transversely thereto to produce working by the tool on and along the curved face while maintaining the tool and workpiece at a desired relation;

sensing means determining the actual relative motion between the tool and workpiece in the curved direction of the face and transversely thereto; and

a tracer having a head following a line of a drawing to be reproduced on the workpiece, the head and drawing having relative movement in linear directions transverse to each other and corresponding to the directions of relative movement between the tool and workpiece, said tracer responding to said sensing means and responding to movement of the head to control said operating means and effect the relative movement between the tool and workpiece to cause working of the tool on the face and along a course corresponding to the shape of the line of the drawing.

2. The operating and control apparatus according to claim I and a template having a peripheral edge shaped identically to the curved face of the workpiece:

said sensing means including a distance measuring wheel bearing against the template edge with predetermined pressure; and

means producing relative motion between the template and wheel identical to the relative motion between the tool and workpiece in the direction of the curved face.

3. The operating and control apparatus according to claim 1 and I said operating means including first means and second means producing rotational and linear relative motion between the tool and workpiece in the curved direction of the workpiece face, and'said operating means also including a third means producing said relative motion between tool and workpiece in said second direction transversely to the curved direction of the face.

4. The operating and control apparatus according to claiml and said operating means including first and second means producing rotational and linear motion between the tool and workpiece, the rotational motion being about an axis to produce progressive travel between the tool and the face of the workpiece, said linear motion being in a direction transverse to the axis of rotation to change the angular relation between the tool and the curved face of the workpiece, and said operating means also including a third means producing such relative motion between the tool and workpiece in a second direction parallel to V said rotational axis. H W g 5 The operating and control apparatus according to claim 3:

said tracer head following the line by simultaneously moving in transverse directions corresponding to the relative motion between the tool and workpiece, to effectively move the tool along a trace of the line on the drawing; and

the tracer also inducing operation of said third means and a selected one of said first and second means to maintain the tool at a predetermined spacing from and all along said trace and thereby allow for tool diameter, rough and finish cut 'ng of the workpiece and other contingencies.

6. The operating and control apparatus according to claim 3:

said tracer inducing operation of the third means and thereby producing relative linear movement between the tool and workpiece and also inducing operation of the first means to produce rotational relative movement between the tool and workpiece for following the trace of the line of the drawing; and

the tracer also inducing operation of the third and second means to produce relative linear movement between the tool and workpiece in transverse directions to maintain the tool at one side of the center of trace to compensate for'the diameter of the tool in rough and finish cutting operations of the workpiece.

7. The operating and control apparatus according to claim 1, and

said tracer having means inducing relative motion between the tool and workpiece in a rotational direction and in a direction parallel to the axis of rotation to cause corrective motion between the tool and workpiece and maintain the tool at one side of said course on the face of the workpiece corresponding to the shape of the line of the drawing.

8. Operating and control apparatus producing relative motion between a tool and a workpiece with a cylindrical face,

comprising:

operating means producing rotation of the workpiece about the axis of the cylindrical face and also producing linear motion of the workpiece along the axis to engage the tool for progressive working of the face;

sensing means determining the rotary and linear motion of the workpiece; and

a tracer having a head following a line of a drawing to be reproduced on the cylindrical face of the workpiece, the drawing lying in a plane and the head moving in a plane in multiple directions to follow the line, the tracer responding to said sensing means and to the movement of the head to control said operating means and effect rotary and linear movement of the workpiece to cause working of the tool on the face and along a course corresponding in shape to the line of the drawing.

9. The operating and control apparatus according to claim 8 and wherein said operating means also produces linear motion of the workpiece transversely of said axis, the tracer con trolling said operating means and selectively effecting rotation of the workpiece and linear movement of the workpiece trans versely of the axis.

10. The operating and control apparatus according to claim 9 and said tracer having means producing linear motion of the workpiece in both of said linear directions transversely of each other and maintaining the tool at one side of the course along the face of the workpiece corresponding to the shape of the drawing.

11. The operating and control apparatus according to claim 8, and

a circular disc with a diameter identical to that of the cylindrical workpiece;

said sensing means including a distance measuring wheel bearing against the edge of the template with predetermined pressure; and

means revolving said disc in the direction of the cylindrical workpiece to turn the measuring wheel and thereby continuingly sense the position of the workpiece.

12. The operating and control apparatus according to claim 8, and

the operating means having a first and second means respectively producing rotary motion of the cylindrical workpiece about its own axis and producing linear motion of said cylindrical workpiece in a direction transversely to said axis, and said operating means also having a third means producing linear motion of said workpiece along the axis;

the tracer having means inducing operation of said third means and said first means to produce working of the face along said course corresponding to the shape of the line drawing; and

said tracer also inducing operation of the third means and a selected one of said first and second means in response to direction of a line on the drawing to maintain the tool at one side of the course being followed corresponding to the shape of the line on the drawing.

13. Operating and control apparatus producing relative mo tion between tool and workpiece for working the face of the workpiece with the tool comprising:

operating means producing linear motion of the workpiece in one direction and selectively producing rotation of the workpiece about an axis extending in said direction and producing linear motion of the workpiece transversely of said axis to engage the tool for progressive working of the face;

sensing means determining the linear and rotary motion of the workpiece; and

a tracer having a head following a line of a drawing lying in a lane, the head moving in a plane in multiple directions to ollow the line, the tracer responding to said sensing means and to the movement of the head to control the operating means and selectively effect rotary and linear movement of the workpiece to cause working of the tool on the face and along a course corresponding in shape to the line of the drawing.

14. Operating and control apparatus producing relative motion between tool and workpiece for working the face of the workpiece regardless of whether the workpiece have a flat or cylindrical face:

operating means producing linear motion of the workpiece in one direction and selectively producing rotation of the workpiece and linear motion of the workpiece in a direction transversely to said one direction and thereby produce progressive working by the tool along the face of the workpiece;

sensing means determining the motion produced at the workpiece relative to the tool;

a tracer having a head following a line of a drawing lying in a plane, the head moving in multiple directions in a plane to follow the line, and the tracer responding to said sensing means and to the movement of the head along the line to control the operating means and selectively produce movement of the workpiece relative to the tool and selected rotary and/or linear directions to cause working of the tool on the face and along a course corresponding to the shape of the line of the drawing; and

whereby with the same drawing, the tool may produce the identical configuration and the workpiece, whether the workpiece be flat or cylindrical.