US3023676A

US3023676A - Index type multiple spindle pantograph machine

Info

Publication number: US3023676A
Application number: US484992A
Authority: US
Inventors: Allen D Gunderson
Original assignee: George Gorton Machine Co
Current assignee: George Gorton Machine Co
Priority date: 1955-01-31
Filing date: 1955-01-31
Publication date: 1962-03-06
Anticipated expiration: 1979-03-06
Also published as: US2866391A

Description

March 6, 1962 A. D. GUNDERSON INDEX TYPE MULTIPLE SPINDLE PANTOGRAPH MACHINE Filed Jan. 31, 1955 .12 Sheets-Sheet 1 m INVENfii BY p 31 +ua ATTORNEYS March 6, 1962 A. D. GUNDERSON 3,023,676

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United States Patent Ofifice 3,023,676 Patented Mar. 6, 1962 3,023,676 INDEX TYPE MULTIPLE SPINDLE PANTOGRAPH MACHINE Allen D. Gunderson, Racine, Wis., assignor to George Gorton Machine Co., Racine, Wis., a corporation of Wisconsin Filed Jan. 31, 1955, Ser. No. 484,992 13 Claims. (Cl. 9013.1)

The invention provides and relates to a multiple spindle, tracer controlled pantograph machine of the index type for scaled reproduction of a master on a work piece by milling, grinding, and the like operations; and the nature and objects of the invention and the several features thereof will be readily recognized and understood by those skilled in the art in the light of the following explanation and detailed description of the accompanying drawings illustrating what I at present consider to be a preferred embodiment or mechanical expression of my invention, from among various other forms, embodiments, constructions and combinations of which the invention is capable within the broad spirit and scope thereof as defined by the claims which are hereto appended.

It is a primary and a general object of my present invention to embody and incorporate a plurality of cutter spindles of the powered pantograph operated, tracer controlled types with a powered indexing worktable, into an integrated organization to provide a multiple cutter spindle, indexing type of machine having a wide range and extreme flexibility of selection of operations, for performing identical profile milling, grinding and the like operations upon multiple Work pieces simultaneously, or to perform identical or different successive operations on one or more work pieces to profile mill, grind, or otherwise form thereon accurately scaled reproductions of multiple patterns or masters respectively controlling and dictating the movements over the work pieces of the multiple cutter spindles of the machine.

A further object is to provide such an indexing type profile milling machine having multiple pantograph operated and tracer controlled cutter spindle units in which each unit has its own powered master for dictating the operations of the pantograph and in which each unit has its own powered cutter spindle drive which is independent of the powered cutter spindle drives of each of the other units.

Another object is to provide a machine having a plurality of such powered master, tracer controlled pantograph milling units in operative association and relationship with a powered rotary work indexing table which provides a plurality of work stations thereon for successively moving or indexing work pieces mounted at such work stations into operative positions relative to the cutter spindles of said pantograph units for the performance by said units of master dictated profile milling operations on such work pieces.

A further object is to provide such a machine in which each tracer controlled pantograph milling unit is provided with a powered master for dictating the operations of its pantograph, with the powered master of each unit operable independently of the powered master of each of the other units in order that masters may be used providing different master patterns for reproduction on work pieces indexed into operative position for profile milling thereon by such milling units.

A further object is to provide such a machine in which profile milling operations may be performed by each pantograph milling unit at a difierent ratio of scaled reproduction from the pattern or master for that unit, from the ratios of scaled reproduction performed byeach of the other milling units from the powered masters for such units, respectively.

Another object is to provide such pantograph operated, master-controlled profile milling units with independent spindle feeds for feeding the cutter spindles of the units to and from operative milling positions.

A further object is to provide such a machine in which the pantograph milling units have independent powered spindle feeds for feeding the spindles into the work during operation on the work and/ or for feeding the spindles to and from cutting relation with the work.'

A further object is to associate and relate such powered cutter spindle down feed mechanisms with the powered masters controlling the pantograph operations of such milling units in an interlocked arrangement for coordinating and synchronizing the operations thereof and for performing automatic milling cycles therewith.

Another object is to provide a powered indexing table in such a machine having a plurality of pantograph milling units in which the indexing table is interlocked with the several milling units in such a manner that the table may be indexed only upon the completion of profile milling operations on a work piece at a work station with the pantograph milling units thereafter rendered inoperative for milling operations during the indexing cycle of the table.

Another object is to provide a system of interlocks by which the indexing table is rendered inoperative for indexing whenever a cutter spindle of one of the pantograph milling units is in milling relation with the work piece.

A further object is to provide an interlock system in such a profile milling machine by which a cutter spindle of any one of the pantograph milling units of the machine cannot be fed to operative milling relation with the work piece during indexing by the index table.

A further object is to provide a reversible, infinitely variable speed drive for the powered master of each of the pantograph milling units of such a profile milling machine so that the rate of movement of a cutter by a cutter spindle through a work piece may be controlled over an infinite range to meet the requirements of the work pieces and the profile milling operations being performed thereon, and further so that the direction of movement of acutter through a workpiece may be reversed, with all of such controls for each pantograph milling unit being independent of the controls for each of the other units.

Another object is to provide an independent and infinitely variable speed control for the powered down feed mechanism of each of the pantograph milling units.

A further object is to provide a cutter spindle down feed mechanism for a pantograph milling unit in which a cutter head and cutter spindle unit is engaged by a forming guide with such forming guide being power fed by the mechanism to feed the cutter spindle.

A further object is to provide such a power fed forming guide with a mounting having cross-compound adjustment for facilitating accuracy of adjustment and wide range of set-up for the forming guide to meet the conditions of any particular milling operation.

Another object is to provide a power driven master unit for a pantograph operated and controlled cutter spindle which will have extreme accuracy in operation for precise movements of a cutter spindle in sealed reproduction of the pattern or master provided by such powered master unit.

Another object is to provide an adjustable mounting arrangement for such a powered master unit by which a wide range of adjustments may be obtained for practical, efficient operations of a master unit for a variety of work pieces and profile milling operations to be performed thereon.

A further object of the invention is to provide a dc sign and arrangement of such a profile milling machine having a plurality of pantograph milling units of the power driven master types in which any desired number of such pantograph milling units may be utilized within the design limits of any particular machine of the invention; and further to arrange such a machine in such a manner that pantograph milling units may be removed therefrom or added thereto as may be desired or required for any particular milling operations.

And a further object is to provide an adjustable indexing table so arranged and integrated with a plurality of pantograph milling units as to permit of a wide variation of indexing positions for the work piece stations on the table relative to the milling cutters of the pantograph milling units to meet the requirements of different work pieces and profile milling operations by adjusting the worktable for different distances or degrees of indexing steps and the indexing sequences thereof.

With the foregoing and various other objects, features and results in view which will be readily apparent from the following detailed descriptions and explanations, my invention consists in certain novel features in design, constructions and combinations as will be fully referred to and specified hereinafter.

Referring to the accompanying drawings in which similar reference characters refer to corresponding parts and elements throughout the several figures thereof:

FIG. 1. is a view in top plan of an index type multiple spindle pantograph machine of my invention which incorporates four pantographic milling units with an indexing table having eight work stations provided thereon.

FIG. 2 is a view in vertical transverse section taken as on the line 2-2.of FIG. 1, with portions of the indexing table and its mounting base being shown in elevation.

FIG. 3 is a view in side elevation of one of the pantograph milling units of the machine of FIG. 1 with a portion of the indexing table being shown in side elevation.

FIG. 4 is a view in top plan of the supporting frame structure for the pantograph milling units and the indexing table of the machine of FIG. 1, with the pantograph milling units having been removed and with the Geneva plates of the indexing table operating mechanism being shown in dotted outline, a portion of the table having been broken away to show the Geneva arm for operative engagement with the Geneva plates.

FIG. 5 is a detail view in vertical section showing the tracer spindle in operative connection with the chain drive therefor of one of the pantograph miling units.

FIG. 6 is a detail view in bottom plan of certain of the components of the operating unit of the indexing table of the machine of FIG. 1.

FIG. 7 is a view in top plan of one of the pantograph milling units and its powered master unit of the machine of FIG. 1, a portion of the indexing table of the machine being shown.

FIG. 8 is a view partly in vertical section and partly in side elevation of a powered master unit and its driving 'mechanism in mounted position on a pantograph milling unit of the machine of FIG. 1.

I FIG. "9 is a detail vertical sectional view through a portion of the chain drive and the tracer spindle carriage of a pantograph milling unit of the machine of FIG. 1, taken as on the line 99 of FIG. 5.

FIG. 10 is a view partly in side elevation and partly in vertical section of one of the pantograph milling units of the machine .of FIG. 1, with the forming guide and portions of'the downfeed mechanism therefor being shown in vertical section with the forming guide in operative relation with the cutter spindle unit shown in side' elevation.

FIG. 11 is a view in front elevation of the downfeed cam, forming guide carriage and associated mechanism of a pantograph milling unit of the machine of FIG. 1.

FIG. 12 is a view in top plan of the downfeed mechanism of FIG. 11, with the downfeed cam housing being shown in horizontal section.

FIG. 13 is a schematic wiring diagram of the several operating motors and power circuits for the machine of FIG. 1.

FIG. 14 is a schematic view of the control circuit network for the example machine of FIG. 1, powered from; the power circuits of FIG. 13.

Basically, my invention is characterized by an index-- able worktable, say a rotary table, on which there is pro vided a plurality of work stations spaced therearound with a plurality of pantographic type milling units spacedapart around the indexing table and each incorporating: therein a rotary cutting spindle which is positioned by the unit over the indexing worktable so that the work sta-- tions on that table may be successively indexed to work-- ing positions below the several cutter spindles. dexing table is suitably powered and the pantograph units also each include a powered spindle drive and a poweredmaster from which the pantograph mechanism of the pantograph milling unit is controlled for effecting operations of the cutter spindle to precisely reproduce on a work piece the pattern or master defined by the powered master. In some instances each pantograph milling unit of the multiple units combined in operative association with the indexing table, is also provided with an independent, powered spindle feed by which the spindle may be fed to cutting position in the work piece at a work station positioned in operative relation with such cutter spindle. And, in accordance with my invention, the powered indexing table and the powered spindle drives, the powered masters and the powered downfeeds of the pantograph milling units are suitably electrically interlocked in a manner to prevent operational interference between the powered mechanisms and the functions which they are intended to perform cooperatively and in proper sequence relationship in the efiicient operations of a machine or organization of the invention in which incorporated and integrated.

Thus, a machine of the invention having the foregoing basic characteristics can efficiently and at high rates of production perform various pattern or master-controlled profile milling operations, in either two-dimensions or three-dimensions, upon work pieces on the work stations indexed to operative positions at the several pantograph milling units. With such an organization, as provided by the invention, each pantograph unit may be controlled by and from a different pattern or master so that different profile milling operations may be performed on work pieces presented to the several pantograph units, respectively, with the result that work pieces of different finished forms may be simultaneously milled to their respective finished forms by the several pantograph units; or work pieces of the same finished form may be milled to such to which the work piece is indexed may perform the finishing operation by which the work piece is completed; or, depending upon the number of pantograph units which the organization includes, several work pieces may be simultaneously rough-milled by one group of the pantograph units and then indexed to another group of the pantograph units for simultaneous finishing milling operations thereon; or work pieces of the same finished form may be simultaneously milled at all or a plurality of Work stations from identical powered masters on the several pantograph units. It is thus a basic characteristic and an important feature of a machine organization of my invention that great work flexibility is obtained and a wide range of milling operations may be performed therewith by various set-ups of the pantograph units through the use of different controlling patterns or masters, as well as by various indexing operations which may be carried out The in-' by the indexing table to present various sequences, or

groupings, or permutations of work stations selectively to the cutter spindles of the several pantograph units.

An exemplification of the principles, constructions, combinations and functions of the invention is presented and disclosed herein in an embodiment which provides an indexing type pantograph milling machine having four (4) cutter spindles each of which is included and incorporated in a pantograph unit for operation by the pantograph of that unit through a tracer dictated and controlled by and from a powered pattern or master uni-t for causing the milling tool or cutter on the cutter spindle of such unit to precisely reproduce on a work piece in accurately scaled relation, the master or pattern defined by the powered master for that unit. Expressions and embodiments of my invention are not, however, in any sense limited to the number of pantograph units and their included cutter spindles which a machine embodiment of the invention may include, as the invention contemplates and intends the provision of machines having two or more pantograph units and cutter spindles thereof, and the invention is not, therefore, limited to the four (4) spindle embodiment of this present example.

Further, in the selected example of the invention here presented, each of the spindle operating pantograph units provides a powered downfeed for a spring loaded, upwardly biased cutter spindle assembly, such feed mechanism being of the type that controls and dictates a progressive feed of the cutter spindle to the work by a master cam which has its independent power means. However, attention is here directed to the fact that the invention is not limited to this type of feed mechanism as it contemplates and includes not only different types of powered feeds for the cutter spindles, but the use of pantograph units having no spindle feeds in the sense of a distinct power feed for those instances where work is to be performed to a constant predetermined depth of cut, all as will be specifically referred to and discussed more in detail hereinafter in the descriptive portions of this specification dealing with the power feeds of the present example.

The pantograph units herein disclosed for the machine of this example are of the two-dimensional type but threedimensional effects can be obtained through the use of so-called forming guides, as will be referred to hereinafter. However, the use in the example machine of pantograph milling units of the two-dimensional type is not in any sense intended to limit the invention to the use of twodimensional units, as pantograph units for three-dimensional work are intended to be employed by and are in cluded in the invention for work piece operations calling for three-dimensional reproduction from patterns or masters. The pantograph units herein disclosed in the example embodiment are of types for performing milling operations by the use of rotary milling cutters, mills and the like, but as will be obvious to those skilled in the art, pantograph units may be provided for grinding operations, or in fact for performing any material removing operations by which a work piece may be shaped or formed, or any portion thereof shaped or formed, in precise scaled reproduction of a master or pattern, and my invention intends use of and includes such material removing operations and any equivalents thereof. And it is here pointed out that for the purpose of brevity the expressions cutter spindle or spindle, are used herein in a broad and generic sense to include the milling cutter, grinding tool or other material removing member to be mounted thereon.

General Organization The general organization of the example machine, referring now to the accompanying drawings, includes the powered index table unit TU which includes and provides the horizontally disposed, rotary worktable T mounted in elevated position on a supporting frame structure which provides a base plate 10 with the vertically disposed structural frames 11 spaced therearound and extending upwardly therefrom and on which a table or platform 12 is mounted in horizontally disposed position on and across the upper ends thereof. This platform 12 is provided with a circular opening 14 therein which is surrounded by anannular member or mounting ring 15 positioned on the upper side of platform 12 and on which the index table unit TU is mounted and supported. The index table unit TU is a self-contained, powered unit for step-by-step work piece indexing rotation of the indexing table T thereof. The supporting frame structure is enclosed by a side wall 16 which is secured therearound in vertically disposed position between the base plate 10 and the elevated platform or table 12. It is to be noted that in this particular embodiment of the invention the table or platform 12 does not extend completely around the central opening 14 thereof but is of horseshoe or arcuate form in plan and terminates at its forward transverse edges 12a and 12b to merge into the front or forward side of the frame structure at spaced locations at opposite sides thereof so as to provide an operator station from which the forward portion of the periphery of the indexing table T is readily accessible for loading and unloading work pieces on those work stations of the worktable positioned at the forward side of the frame structure by indexing rotation of the worktable.

In this example four (4) pantograph milling units P1, P2, P3, and P4 are mounted on the elevated platform 12 in positions spaced equidistant apart angularly around the indexing table T with each of these pantograph units being located radially relative to the center or axis of rotation of the indexing worktable T. The pantograph milling units P1, P2, P3, and P4 include the vertically disposed cutter spindles S1, S2, S3, and S4, respectively, positioned thereby for independent universal lateral movements over the indexing worktable T and the path through which the work stations on the indexing table T are indexed or displaced by rotation of that table.

In the example machine having four (4) pantograph units, the rotary indexing table T of the powered index table unit TU is provided on the upper side thereof spaced therearound adjacent but spaced inwardly from the periphery of the table with a plurality of work stations W1, W2, W3, W4, W5, W6, W7, and W8. The rotary index table unit TU may be set-up for indexing through steps 45, or or in fact any desired angular distance of indexing step, depending upon the requirements of the particular work pieces to be produced and of the milling operations to be performed thereon, all as will be explained hereinafter in detail. In the arrangement and setup of the machine here disclosed the pantograph units P1, P2, P3, and P4 are all located spaced apart on and around the platform 12 of the supporting structure at the rear of a center line across the machine passing through the axis of rotation of the indexing table T from left to right when facing the machine, with the pantograph unit P1 positioned with its longitudinal center located 22 /2 the pantograph unit P2 positioned with its longitudinal center located 67 /2 the pantograph unit P3 positioned with its longitudinal center located 112 /2; and the pantograph unit P4 positioned with its longitudinal center located 157 /2 rearwardly around the half-circle from such center line. Thus, each of the pantograph units P1, P2, P3, and P4 is positioned with its longitudinal center located radially relative to the axis of rotation of the indexing worktable and spaced equal angular distances apart on the platform 12 around the rear side of the indexing worktable T. Thus, for indexing by the worktable T to locate the work stations W1, W2, W3, W4, W5, W6, W7, and W8 successively in operative positions at the cutter spindles S1, S2, S3, and S4, the work stations in this example machine are located at positions spaced 45 apart on and around the indexing worktable T of the index table unit TU.

Inlthis instance the index tableunit TU is operated and driven by an electric motor TM and, as will be hereinafter described and explained in connection with the operating control system for the example machine, may be either automatically operated through the milling cycle being performed by the pantograph units P1, P2, P3, and P4, or may be manually controlled by the operator from the operator station at the front side of the machine to index the table T and the work pieces thereon for each indexing step of the cycle.

The pantograph milling units P1, P2, P3, and P4 have their own powered cutter spindle drives which include the electric motors SM1, 8M2, SM3, and 8M4, respectively, mounted thereon as self-contained components thereof. The pantograph milling units P1, P2, P3, and P4 have their respective cutter spindles controlled in their movements over the work pieces being milled by separate and independent powered masters M1, M2, M3, and M4, respectively, which include the driving electric motors MM MM2, MM3, and MM4. The independent spindle drives for the pantograph milling units which are respectively operated by the motors SM1, 5M2, SM3, and SM4 are under the control of the operator through master stop and start switches in the control circuits for the machine, such switches being located in an accessible position at the operator station at the'front of the machine, as will be referred to hereinafter in describing and explaining the control circuit network for the example machine. Similarly, the driving motors MM1, MM2, MMS, and MM4 for the powered master units M1, M2, M3, and M4, respectively, are under the control of the operator through a control switch located at the operator station so that these powered masters may be simultaneously placed in operation with the start of operation of the cutter spindles S1, S2, S3, and S4 of the pantograph units.

In those machine organizations such as that of the example embodiment hereof, the pantograph milling units are provided with powered spindle feeds by which the cutter spindles of the pantograph units are fed to and from operative working positions, and these powered spindle feeds may include electric motors carried and mounted together with the feed mechanisms operated thereby, as self-contained components of the pantograph units. In this instance the power feeds for the cutter spindles S1, S2, S3, and S4 of the pantograph milling units P1, P2, P3, and P4 include the spindle feed driving motors FMI, FMZ, FM3, and FM4, respectively. The motors FMl, FMZ, FM3, and FM4 are connected into the control circuits for the machine in such a manner that upon starting the milling cycle by starting the cutter spindle drives and the powered master units for the pantograph milling units, the spindle down feed motors are simultaneously placed into operation, as will be referred to in the description of the control circuit network and the functioning of the ma- 7 chine which appears hereinafter.

While it forms no part of my present invention, a coolant system is provided for the example machine by which coolant is discharged in the usual manner on the work pieces and milling cutters engaged therein during the milling operations at the several work stations on the index table T. Such coolant system in this instance includes a coolant tank 17 mounted within the supporting frame structure, with a coolant pump and operating electric motor unit CM mounted in operative relation with said tank for forcing coolant therefrom under pressure to the discharge points at the cutter spindles through a coolant supply system (not shown). An annular vertical wall 18 having a greater internal diameter than the diameter of the indexing table T is mounted on platform 12 surrounding and concentric with the circular opening 14 in that platform and with the table T. Thus this circular vertical wall is spaced outwardly a'distance from and around table T and forms with the portion of the platform 12 enclosed thereby an open top annular trough for drainage thereinto of coolant from the upper side of the table T over and around the peripheral edge of that table. A return flow or drainpipe line 19 is provided for flow of coolant from the receiving trough provided by the circular wall 18 and platform 12 back to the tank 17. The coolant pump motor CM is in this example in a separate, independent circuit controlled by a switch to be referred to and identified hereinafter by which the operator may start and stop operation of the coolant system by the motor CM as he may desire and independently of the various other electrically operated components and mechanisms of the machine. Thus, with the machine of the example having the general organization and formed of the components and mechanisms as hereinabove generally identified and described, the operator may stand at the operator station and through the actuating members for the electrical control switch components which are located in readily accessible position on a control box or panel CB, set the machine into the selected two-dimensional or three-dimensional milling operations at the work stations indexed to the pantograph milling units, while unloading work pieces from and loading work pieces to be milled on the work stations exposed to him at the operator station by the indexing worktable.

The Powered Index Table The powered index table unit TU, per se, of the present machine example forms no part of my present invention and, therefore, may be of any desired design and construction capable of functioning to meet the requirements placed upon such a table unit by the integrated machine organization hereof. Suffice it for purposes of this disclosure to state that the unit TU includes a circular base 20 which is mounted on and around the ring member 15 which surrounds the circular opening 14 in the elevated platform 12 with the rotary table T being journaled on a suitable vertically disposed pivot stud 21 mounted on base 20. A suitable powered drive indicated generally by the reference character 22, is provided for rotating the indexing table T through its index steps, this drive including a pulley 23 on the outer end of a power input shaft 24. The indexing unit TU is powered by the motor TM which is adapted to be continuously operated. The motor TM is mounted in position suspended below the base 20 by a horizontally disposed motor mounting plate 25, the motor TM being mounted and supported on the plate in horizontally disposed position with its armature shaft 26 parallel with the input shaft 24. The motor driven or armature shaft 26 mounts on an outer end thereof the driving pulley 27 which is connected by a suitable driving belt 28 in driving connection with the pulley 23 on the input shaft 24. This rotary index table unit TU is of a design, construction and operation familiar in the art and is of that well-known type in whichthe underside of the table T mounts thereon so-called Geneva plates 29 which are operatively engaged by a so-called Geneva arm 29a which is mounted and journaled in position at the upper side of the base 20 for operative engagement with the Geneva plates. The Geneva arm-29a on the base 20 is rotated from the power drive 22 of theunit and successively engages the Geneva plates 29 on the table to thereby rotate the table in successive steps with intervals therebetween at which the table is at rest and in locked position, through angular distances as determined by the particular size and set-up of the Geneva plates and the Geneva arm which engages such plates and rotates or indexes the table through its successive index steps.

The motor TM by which the rotary index table unit TU is powered is suitably connected into the power and control circuits of the machine of this example for indexing operation under the control of the operator, as will be hereinafter fully described and explained. During operations of the machine the motor TM of the indexing unit TU is continuously operated, and suitable clutch mechanisms familiar to the art in this type of unit, are utilized to engage and disengage the Geneva arm withand from the driving mechanism therefor which is powered by the motor TM.

As this type of indexing table unit TU is in commercial use and well known, it will only be necessary herein to specifically refer to and disclose those of the elements and components of the unit which are operatively related and controlled and synchronized with components and mechanisms of the machine of my present invention.

Referring now to FIG. 6, the unit TU includes a latch plate 2% which is rotatably mounted and which is associated with and controls the rotation of the Geneva arm 29a. This rotary latch plate is in turn controlled by a pivoted lock arm 29c which is adapted to be engaged with the latch plate. The lock arm 290 is in turn controlled by and from a latch lever 29d, which is under the control of the latch return spring 296. The latch lever 29d is pivotally coupled by a link 29 with the outer end of the armature 29g of the actuating solenoid 207.

A limit switch 1LS, which may be of the microswitch type and which is normally open is incorporated in the table index unit TU and has an actuating member 2912. The rotary latch plate is provided with operating pins 29k thereon which are adapted to engage the switch actuating member 2911 as they reach predetermined positions in the step-by-step rotation of the latch plate.

in the operation of the index table unit TU in the example machine, when it is desired to effect indexing of table T through an index step, the solenoid 207 is energized which, through link 29,, causes the latch lever 29d to release the lock arm 290 from contact with the latch plate 29!). The latch plate 29]) rotates with the Geneva arm 29a which in turn results in indexing rotation of the table T to its next position of index where it is locked by the unit until it is again actuated through an indexing step. As the indexing table T goes into its locked position of index, an operating pin 29k will engage the switch actuating member 29/1 and cause an operation of the switch to momentary closed position. Upon release of operating engagement of member 29h by a pin 29k, the switch 1LS will automatically return to its normal open position.

The Powered Master-Driven, Tracer-Controlled Pantograph Milling Units The pantograph milling units P1, P2, P3, and P4 are of identical design and construction and include the identical rotary cutter spindles S1, S2, S3, and S4, respectively, which are universally laterally movable by the pantograph milling units in two dimensions, while in units for three-dimensional work are adapted to be axially movable in the third dimension. As each pantograph milling unit is identical in construction and in functioning in the example machine, a detailed description of the construction and functioning of one of such units will suffice as a description for all of the units. Hence, referring to the pantograph milling unit P3 as shown in FIG. 2, a base 30 is provided by which the unit is securely mounted and attached in rigid position on and to the upper side of the elevated platform 12 of the supporting structure for the example machine. From the base 30 a vertically disposed column 31 extends upwardly and terminates at its upper end in a forwardly, inwardly extending neck 32. The unit P3 is mounted in position on the platform 12 so that the longitudinal center through the column 31 and its inwardly extending neck 32 lies on a radius line passing through the axis of rotation of the index table T, and each of the other units P1, P2, and P4 with their columns and inwardly extending necks 32 is also so mounted and positioned on platform 12 and relative to the index table T and its axis of rotation. The column 31 and its neck 32 are preferably cast or otherwise formed integral and on the upper side from end to end thereof there is provided the longitudinally disposed slideway 32'. The

' column 31 of the unit P3, and of each of the other units,

has cast integrally therewith, or otherwise provided thereon, the horizontally disposed, vertically spaced ears 1t) 33 which are positioned adjacent the outer end of one side thereof and extend outwardly from and at an angular relation to the column. In this particular instance, these spaced cars 33 on the column 31 of each pantograph unit extend from the left-hand side of the column when facing a unit from the front or operator station of the machine. These spaced ears 33 form a bracket structure in and between which there is journaled for rotation about a vertical axis a pivot shaft 34 which is formed on or which carries the inner end of a motor mounting arm 35 which extends outwardly from one side of the cars 33 and which mounts and supports at the outer end thereof the spindle driving motor for the unit, being the motor SM3 in the case of the pantograph milling unit P3 now being described. The motor mounting arm 35 is provided with a laterally outwardly extending mounting plate 36 adjacent the outer end thereof which mounts thereon at the outer side of the arm 35 the motor SM3 in position with its armature or driving shaft vertically disposed and ex tending through the mounting plate with a pulley 37 mounted on the upper end of the shaft above plate 36. Thus the cutter spindle driving motor for each pantograph milling unit, such as the motor SM3 of the unit P3, is mounted and carried by the arm 35 and the pivot shaft 34 for horizontal swinging through an arcuate path in either direction about the axis of shaft 34 as a center. The functioning and the purpose of such horizontally swingable spindle drive motor mountings for the pantograph milling units will be described more in detail hereinafter.

On the same side of the column neck 32 at which the motor mounting cars 33 are provided but adjacent the inner end of the neck 32, there is provided an outwardly and inwardly extending horizontally disposed arm 38 which at its outer end provides in this example integrally therewith the horizontally disposed vertically spaced ears 39 for pivotally mounting therein the cutter head and cutter spindle carrying links which are actuated by the pantograph linkage of the pantograph milling unit, as will be described and explained in detail hereinafter.

A slider head 40 is mounted on and slidably received in the groove or slideway 32' on the upper side of the neck 32 of each column structure of a pantograph milling unit, such as the unit P1. This slider head is an elongated member having a length relative to the column 31 and its neck 32 such that in normal position the inner end thereof extends a slight distance radially inwardly over the adjacent peripheral portion of index table T and the outer end thereof extends over and above the upper end of the column 31 and its neck 32. The outer length portion of the slider head 40 of each pantograph milling unit is provided with a longitudinal groove or slideway 41 thereacross with a slot 42 extending through the slideway for a substantial portion of the length thereof. The slider head 40 is provided with another groove or slideway 43 therein disposed longitudinally thereof and extending inwardly from the inner end of the slideway head to a location with its outer end spaced a distance inwardly from the inner end of the slideway 42, all as will be clear by reference to FIGS. 7 and 8 of the drawings. The inner end length slideway 43 of the slider head 40 is provided with a slot 44 through the head for a distance along the bottom of the slideway for a purpose to be hereinafter described.

Each'slider head 40 of the pantograph units P1, P2, P3, and P4 has extending from one side thereof in laterally offset relation thereto, in this instance the right-hand side thereof when facing the pantograph units from the index table T, a column or post 45 which is cast integral with the slider head and which extends vertically upwardly spaced to one side of the slideway 43 adjacent the inner end of the slider head. A hanger arm 46 is formed integral with the upper end of the post 45 and extends inwardly therefrom in horizontally disposed position over and across the adjacent inner end of the slider head 40to' a position with its inner end disposed over the table T spaced a distance inwardly from the innerend of the slider head 40. The inner end of the hanger arm 46 mounts or receives therein a pivot pin or stud 47 which is adapted to pivotally mount thereon the pantograph linkage 50 of the pantograph milling unit, as will be hereinafter described.

The pantograph milling units P1, P2, P3, and P4 are' provided with pantograph linkages 50 of the parallelogram type, each of which includes the parallel upper bars 51 pivotally coupled at their opposite ends to the adjacent ends of the parallel lower bars 53. Each pantograph linkage 50'is pivotally hung and supported in horizontally disposed position from the underside of the hanger arm 46 of the slider head 40 by the pivot pin or stud 47 which pivotally connects with the usual slider block 54 on the adjacent upper arm 52 of the pantograph linkage. Thus mounted, the pantograph linkage 50 is swingable in a horizontal plane about the pivot pin or stud 47. One of the lower bars '53 is extended outwardly across and :above the slider head 40 to provide the outwardly extending tracer arm 55. The pantograph linkage for each of the pantograph milling units P1, P2, P3, and P4, which is controlled and operated about the pivot pin or stud 47 by the tracer arm 55, is adapted to be coupled to a cutterhead or cutter spindle barrel assembly 60 which mounts and journals therein the rotary cutter spindle for the pantograph milling unit.

Each of the rotary cutter spindlesSl, S2, S3, and S4 is identical and each is mounted in its pantograph unit by an identical cutterhead 69 for operation in an identical manner under the control and dictation of the pantograph linkage 50 for the pantograph milling unit in which such cutterspindle is incorporated. In this example each cutter spindle is mounted and journaled in the cutterhead assembly or unit 60. Each cutterhead and cutter spindle unit 60 includes the barrel or casing 61 having at the upper side thereof and located axially thereon the vertically upwardly extending follower point or guide pin 62. The cutter spindle, say for example, the cutter spindle S1 of the pantograph unit P1 is journaled in the casing 61 to form therewith the unit cutterhead assembly 60 which is adapted to be mounted in the pantograph unit in position with the cutter spindle, say cutter spindle S1, in vertically disposed position and axially aligned with the follower or guide pin 62 at the upper side of the cutterhead unit 60;. In certain instances the cutter spindle is mounted in the barrel or casing of a cutterhead and spindle unit for vertical axial movements therein, while in other instances such a cutterhead and spindle unit 60 is'mounted for vertical displacement bodily as a unit on the structure on which mounted to thereby vertically axially displace and raise and lower the cutter spindle from and to its operative milling position. As the specific construction of the cutterhead and cutter spindle unit utilized forms no part of my present invention, except insofar as the .um'tis located and functions in integrated and combined relationship in a machine organization of the invention, it is not believed necessary to make any detailed disclosure thereof herein. Such cutterhead and spindle units are known to the art and are in use, being exemplified in such US. patents as Nos. 1,562,237, 1,956,505, 1,959,269, ;2,0QO,8 38,'2,557,876, 2,645,161, and 2,658,423.

Each cutterhead and cutter spindle assembly forming .u'nit 60 is adaptedto be mounted for universal lateral movements in a horizontal plane under the'control of the pantograph linkage 50 of apantograph milling unit by a system of supporting links pivotally mounted for horizontal swinging on and from the arm 38 and cars 39 thereof which extend from one side of a slider head 46, as hereinbefore referred to and described. This cutterhead and cutter spindle unit mounting linkage, referring now tically disposed pivot pin or stud 63' extending-between and mounted at its opposite ends in the spaced ears 39, and a cutterhead mounting and carrying link 64 which is pivotally coupled by pivot pin'65 to the outer free end of the link 63. This cutterhead mounting link member 64 extends horizontally from the link 63 and is formed to provide the vertically spaced, generally parallel upper and

lower arms

66 and 67 which are unconnected and spaced apart at their outer free ends to form an unobstructed space therebetween. The cutterhead and cutter spindle unit 60 for each pantograph milling unit in which the

linkage

63 and 64 is included, is mounted in vertically disposed position on the upper side of the lower arm 67 of the link 64 in position between that arm and the upper arm 66. The overall height or vertical dimension of the cutterhead and spindle unit 60 between the lower end thereof on arm 67 and the upper end or follower point of the pin 62 is less than the distance of the spacing between the

arms

66 and 67, so that there is unobstructed space between the upper end or follower point of the pin 62 and the upper arm 66 of the cutterhead unit mounting and carrying link 64. In this example in mounted position of a cutterhead and cutter spindle unit 60 on the lower arm 67 of the link 64, the cutter spindle is suitably spring-loaded and in effect floating, being continuously biased in the upward direction toward its raised inactive position. 'Thus the cutter spindle is fed downwardly to operative milling position by forces applied thereto through the follower pin 62 to overcome the biasing forces applied by the spring loading for the cutter spindle.

Each of the cutter spindles S1, S2, S3, and S4 is mounted and journaled in and forms a component of a cutterhead assembly or unit 60, and in each instance with a unit 60 and its cutter spindle in mounted operative position on the lower arm 67 of a link 64, the cutter spindle itself extends downwardly through and a distance below the arm 67 of the link 64 on which it is mounted. A driven pulley 68 is mounted on and fixed to each cutter spindle on the depending length thereof which extends below link arm 67 on which it is mounted. The driven pulley 68 on each cutter spindle is connected in driven relation by a belt B with the driving pulley 37 which is mounted on the power shaft of the cutter spindle drive motor swingably carried by thearm 35 of the pantograph unit of which such cutter spindle forms an operating component. A push-pull rod 69 is connected between the lower arm 67 of the link 64 in each pantograph milling unit and the motor mounting or support plate '36 on such arm 35 to cause the link 64 and the cutterhead unit 60 mounted thereon to swing together with arm 35 and the drive motor mounted thereon to thereby maintain the desired positioning and relation between the motor and its driving pulley 37 and'the cutter spindle and its driven pulley 68 of the cutterhead 60 carried by the link 64. Each push-pull rod 69 isrotatably secured'or coupled to the motor mounting plate 36 of the swingable arm 35 in position with its longitudinalaxis passing through the vertical axis or center about which pulley 37 is rotated. Such rotatable coupling is made by providing the pushpull rod 69 with a ring or collar at its outer end which is connected to the motor mounted plate 36 concentric with the driving shaft of the motor and the pulley 37 mounted thereon for rotation thereon and relative thereto. Each pantograph linkage 50 of each of the pantograph milling units P1, P2, P3, and P4, has a slider block 56 slidably mounted on that lower bar'53 thereof which is parallel with the opposite lower bar 53 which provides and from which the tracer arm 55 extends. The slider block 56 of each pantograph linkage 50 is pivotally coupled by means of a pivot pin or stud 57 with the upper arm 66 of the cutterhead carrying link 64 which is positioned directly therebelow. The slider block pivot pin 57 is positioned in axial alignment with the cutter spindle each pantograph linkage 50 under the control of the tracer arm 55 will correspondingly universally laterally swing the link 64 and the cutter spindle of the cutterhead unit 60 carried thereby universally laterally over a work station of the rotary index table T which may be positioned therebelow. Each of the cutter spindles S1, S2, S3, and S4 is driven and rotated from its driving motor SMl, SM2, 8M3, and 5M4, respectively, as it is universally laterally swung by the operation of a pantograph linkage 50 through the driving belt B, the arm 35 with the spindle drive motor mounted thereon swinging horizontally about the pivot pin 34 with the distance between the axis of the motor and the cutter spindle which it drives being maintained constant through the medium of the push-pull rod 69 which transmits the movements of the link 64 as following movements of the cutter spindle driving motor.

The Powered Master Units The universal lateral movements of the cutter spindle of each of the pantograph milling units P1, P2, P3, and P4 is effected through the actuation of the pantograph linkage 50 by the tracer arm 55 under the dictation and control of the powered master units M1, M2, M3, and M4, respectively, each of which is mounted on the outer length of the slider head 40 of the pantograph milling unit spaced outwardly a distance from the pantograph linkage 50 for that unit. It so happens that in this example the patterns or masters defined by the master units M1, M2, M3, and M4 are identical but it is to be understood that the pattern or master defined by each of the powered master units may be different from the pattern or master defined by the others, or by each of the others, and further, that such powered masters are interchangeable and removable for replacement by master units defining difierent patterns or masters to be reproduced on a work piece by the cutter spindle of the pantograph milling unit in which such master is included' As each of the powered master units M1, M2, M3, and M4 of this example is identical as to construction, assembly, mounting, and functioning, it will only be necessary to specifically describe and explain one of the units, say the unit M1, for purposes of describing and explaining all of the units.

A powered master unit M1, M2, M3, or M4, is basically comprised of a master plate 70 which has formed therein a recess or pocket 71 open through the upper side of the plate, the side and end walls of which provide precisely finished and connected side surfaces 72 and end surfaces 73 which provide a continuous and uninterrupted endless master or pattern defining surface, a precise and scaled reproduction of which is to be milled or otherwise formed in a work piece. It will be noted that with the pattern or master plate 70 the opposite end wall surfaces 73 of the pattern defining pocket or recess are formed on a radius and join and uninterruptedly merge with the opposite side wall surfaces 72. While a particular form, shape, and contour of pattern or master defining recess 71 is shown for the master plate 7t), it is to be understood, of course, that the variety of shapes, forms, and contours for such pattern or master defining recess is infinite, so the invention is in no sense limited or restricted to any particular pattern or master within, of course, the practical limitations of one of these powered masters and of the milling operations which they are to dictate and control.

As the powered master units M1, M2, M3, and M4 of this example are of the chain drive type, each master plate 70 having the pattern or master recess 71 formed therein is provided with a groove opening throughout its length through the top surface of the plate to provide a chain way or chain guide channel 74. In this example the chain way or guide channel 74 of each master plate 70 surrounds and conforms to the general contour of the 14 pattern or master defining recess 71, as will be clear by reference to FIG. 7 in connection with FIG. 8.

The master plate 70 of each of the master units is provided with the spaced parallel slots 75 therethrough which in this instance are disposed with their longitudinal axes transverse to the pattern or master recess 71 and the chain way 74, being located between that chain way and a side edge of the master plate. A sub-base or slider plate 76 having a slide rib 77 thereon is slidably mounted on the outer length portion of a slider head 49 with the slide rib 77 slidably received and engaged in the slideway 41 of the slider head. Thus, the sub-base or slider plate 76 is slidable in either direction, that is, inwardly or outwardly on slider head 40 along a straight line path lying on a radius passing through the center of rotation or axis of the index table T. Suitable locking screws or bolts are provided for detachably securing the slider plate 76 in an adjusted position on the slider head '40, such screws or bolts being extended upwardly through the slot 42 which opens through the slider head in the bottom of the slideway 41.

A master plate 70 is mounted on the slider head mounted slider plate 76 in position with the slots 75 of the master plate disposed normal to and across the straightline path of adjustment of the slider plate on the slider head 40, with that half of the master plate 70 that has the master recess 71 and the chain way 74 therein extending inwardly from the slider head and slider plate toward the pantograph linkage mounting post 45. Thus mounted and positioned, it is to be noted that the master defining recess 71 and its surrounding chain way 74 are positioned disposed generally parallel with the slider head 40 and generally radially relative to the index table T. The slider plate 76 has attached thereto in position extending vertically upwardly therefrom the locking bolts or screws 78 which are headed at their upper ends, as by nuts threaded thereon and which extend through the slots 75 in a master plate 70 for engaging on the upper side of the master plate or suitable shoulders formed within and around the slots 75. Thus, by loosening the bolts 78 the master plate 70 may be adjusted transversely of the slider head 40 in either direction along a straightline path normalto the path of adjustment of the slider plate 76. This mounting and arrangement of a master plate 70 and slider plate 76 on a slider head 76 provides for crosscompound movements of the master plate in order to adjust that plate and its pattern or master-defining recess for work set-up purposes, as will be readily understood by those skilled in the art.

A master plate 70 thus mounted on the slider head 40 of a pantograph milling unit of the invention is in a position such that the tracer arm 55 of the pantograph linkage 50 for that unit extends outwardly over and above the portion of the master plate in which the pattern or master recess 71 and the chain way 74 are formed and provided In accordance with the principles of my invention the tracer arm 55 of the pantograph linkage is operatively coupled with a chain drive mounted in the chain way 74 for causing a stylus or tracer mounted on the end of the tracer arm to follow the pattern or masterdefining surfaces 72 and 73 of the master recess 71. In carrying out these principles in the present example, I provide an endless roller-type chain 80 which is placed in the endless chain way 74 in slidable engagement at one side thereof with the bottom wall 74' of the chain way for movement of the chain through and around the chain way. The chains 80 of the master units M1, M2, M3, and M4 are power driven by electric motors MMl, MM2, MM3, and MM4, respectively, mounted on and carried by the master plates 70 of the units. Each chain 80 is moved through and around its chain way 74 from its driving motor, by a sprocket wheel 81 which is mounted in the master plate 70 in position at the inner curved end 73 of the chain way in position at the inner side of the .bight or bend of the chain located in and passing around and through such curved end of the chain way. The chain driving sprocket 81 is horizontally .disposed'and is mounted on a driving shaft or spindle 82 which is journaled in vertically disposed position in the upper horizontal arm 83 of a motor supporting and mounting bracket structure, identified generally by the reference character 84, which is mounted and attached at the underside of a master plate 70 in position depending downwardly therefrom. The shaft 82 is journaled in a bearing assembly 85 and extends therefrom downwardly through the bracket structure 84. The shaft 82 at its lower end is journaled in an anti-friction bearing assembly 86 mounted on the bracket structure 84. A Spur gear 87 is mounted on the shaft 82 for rotation therewith at a location spaced below the bracket arm- 83 and the sprocket 81 thereabove. A'reversible, infinitely variable speed drive unit 88 is mounted on the bracket structure 84 in position at the outer side of the shaft 82 and having a vertically disposed power output shaft 88a extending upwardly therefrom. A spur gear 89 of smaller diameter than the gear 87 is mounted on the upper end of shaft 88a in position on such shaft in the plane of and in driving mesh with the gear 87. The motor MM MM2, MM3, or MM4 of the powered master unit M1, M2, M3, or M4, is mounted and secured at the lower end of the bracket structure 84 mounted on the master plate 70 of the unit in position with itsv armature shaft 88b vertically disposed and extending upwardly therefrom in vertical axial alignment with the input shaft 88c of the infinitely variable speed drive unit 88. The input shaft 880 extends downwardly from the unit 88 and is suitably operatively coupled in driven relation With the armature shaft 88b of the master unit motor, say, for example, the motor MMl of master unit M1, as shown in FIG. 8.

The infinitely variable speed drive unit 88 is provided with a manual control lever 888 which extends radially outwardly from the upper end thereof by which the operator may selectively set the unit for delivery of the required rate of speed of rotation of the off-take or output shaft 88a and thus determine the rate of rotation of the sprocket 81 and the rate of speed of movement of the chain 80 through and around its chain way. The motor armature shaft 88b and the variable speed unit input shaft 88c are coupled by a suitable reversible coupling unit 88d which provides a radially outwardly extending manual 'control lever 88R by which the direction of rotation of the variable speed unit input shaft 880 may be reversed to thereby reverse the direction of movement of the chain 80 through and around the chain way 74.

The power driven roller chain 80 of each of the powered master units M1, M2, M3, and M4 is adapted to move a tracer or stylus 90 which is coupled with and is adapted to actuate the tracer arm 55 of the pantograph linkage of the pantograph milling unit. The tracer or stylus 90 in this example is comprised by a stud or pm 91 on which there is journaled and rotatably mounted a tracer roller 92 which is positioned in the pattern or master defining recess 71 for rolling engagement on and around the pattern or master-defining

surfaces

72 and 73 of the recess 71. The tracer roller 92 has a diameter less than the minimum width at any point of the masterdefining recess 71 of its master plate 70 so that this tracer roller may be held in rolling contact against and moved around to follow the endless pattern surface provided by and around the outer sides of that recess. A tracer or stylus carriage 93 is provided for connection With the power driven chain 80 and for coupling with the tracer or stylus 90 for moving the latter in following or tracing engagement with and around the master defining surfaces or the recess 71 in a master plate 70. The carriage 93 mounts therein the spaced pins or studs 94 which depend therebelow and which mount the rollers 95 journaled on their lower ends below the carriage. The carriage 93 is mounted in operative position one master plate 70 wit the spaced rollers 95 thereof positioned in the chain way 74 above the chain in that chain way. In this specific example the chain way 74 has the upper portion thereof above the chain 80 formed of increased width to provide the spaced shoulders 74 above and at and around opposite sides and ends of the endless chain 80,, from which the opposite vertical surfaces extend upwardly to form tracks against which the rollers may have rolling contact as the carriage is moved around the chain way by powered drive of the chain 80. One of the roller mounting pins 94 of the carriage 93 is extended downwardly a distance below the other of the pins 94 to provide a driving link pin 96 which is pivotally coupled and connected to a link of the driving chain 80 in a manner which will be clear by reference to FIG. 9. Thus, movement of the chain 80 around the chain way 74 will correspondingly move and carry with it the tracer carriage 93 which is pivotally connected thereto at the one point only provided by the driving link pin 96.

A slider bar or coupling member 100 is slidably yieldingly mounted in and extending transversely through the carriage 93 with its inner end positioned over and above the pattern or master-defining recess 71. The slider bar or coupling member 100 extends outwardly a distance across a master plate 70 to terminate with its outer end located spaced a distance inwardly from the adjacent outer edge of the master plate. This coupling member 100 in this example takes the form of an open rectangular frame closed at its opposite ends and mounting therewithin a biasing spring 101 which may be of a coil type engaged at its outer end over an adjusting screw 102 threaded through such outer end of the member. The inner end of this biasing spring 101 is engaged at its inner end against the outer side of a pin or lug 103 mounted in fixed position in the carriage 93 and extending upwardly therefrom into the hollow frame which forms the coupling member 100, as will be clear from FIG. 5. Spring 101 is positioned between screw 102 and the pin or lug 103 on the carriage 93 under compression so that'it acts to continuously bias the slidably mounted coupling member 100 outwardly through the carriage. The inner end of the slider bar or coupling member 100 is provided with a vertical bore therethrough in which there is mounted an annular microbearing 104 which provides axially therethrough a bore 105 for pivotally receiving and journaling therein a follower pin mounted in the end of a tracer arm 55.

The tracer arm 55 of a pantograph linkage 50 extends outwardly 'over the chain way 74 of a powered master unit, and in accordance with my invention I pivotally couple the outer end of a tracer arm 55 to the slider or coupling member 100 of the chain driven carriage 93, of a powered master unit, so that movements of the carriage and the coupling member thereon are transmitted to and translated as horizontal swinging movements of the tracer arm. In this specific example I provide a follower pin 106 in vertically disposed position extending transversely through the outer free end of a tracer arm 55 with the follower pin extending into the bore 105 of the microbearing 104 in the inner end of the slider or coupling member 100, so that the follower pin is rotatably mounted and journaled in and operatively connected to the coupling member 100. The lower end of the follower pin 106 may, as in the example hereof, be formed with an axial bore extending upwardly thereinto which fits down over and receives therein the pin or stud 91 of the tracer or stylus 90 with the follower pin 106 and the stud 91 being in axial alignment, to thus connect the follower pin and tracer or stylus for lateral movements together as a single unit. As the chain way 74 may not'run truly parallel with and around the pattern or master surfaces 72 and 73 of the master recess 71, it follows that the distance between the axis of the follower pin 106 and of the link pin 96 on the carriage 93 may not remain constant as the carriage and the tracer or stylus are moved through