US2456741A - Boring mill - Google Patents

Description

Dec. 21, 1948. sc 2,456,741

BORING MILL Filed Aug. 8, 1945 i0 Sheets-Shgaet 1 UTTU E. SEHURR ATTO R N EYS o. E. SCHURR 2,456,741

BORING MILL Filed Aug. 8; 1945 A 10 Shets-She'et 2 INVENTOR OTTO ESE-(UHF.

ATTORNEYS O. E. SCHURR Dec. 21, 1948.

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' .BORING MILL- Filed A ug. 8, 1945 1O Sheets-Sheet 6 2&0 Z40 IIHHL LM I 11 so H510 INVENTOR El TTU E. 5 EII-IURR ATTOR o. E. scHuRR Dec; 21, 1948.

BORING MILL l0 Sheets$heet 7 Filed Aug. 8, 1945 ATTORNEYS 0. E. SCHURR 2,456,741

BORING MILL 1O Sheets-Sheet, 8

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Filed Aug 8, 1945 Dec. 21, 1948. Q. SQHURR- 2,456,741

BORING MILL Filed Aug. 8, 1945 l0 Sheets-Sheet 10 w .55 J i wl" 1' m r; '1 EN L O- J rg; v-

, INVENTOR EI'ITD EEEHURR ATTORNEYS Patented Dec. 21, 1948 UNITED STATES PATENT OFFICE mesne assignments, to Lima-Hamilton Corporation, Hamilton, Ohio, a corporation of Virginia Application August 8, 1945, Serial No. 609,625

This invention relates to improvements in transmission and control mechanism for machine tools. More particularly, this invention pertains to an improved feed and rapid traverse control for a vertical boring mill.

One of the objects of this invention is to provide an improved transmission and control mechanism for the cutting tools of a vertical boring mill.

Another object is to provide an improved feed and rapid traverse transmission for a vertical boring mill which is readily adjustable for any desired operating condition with a minimum of effort and skill required on the part of the operator.

Another object of this invention is to provide an improved hydraulic servo operated tool actuating system for a vertical boring mill.

Still another object is to provide a hydraulic servo operated feed mechanism having infinitely variable feed adjustment together with a range selection adjustment.

Still another object is to provide a hydraulic servo operated actuating system for the cutting tools of a boring mill which may be readily adjusted for any desired feed or rapid traverse movement of the cutting tools.

Still another object of this invention is to provide a tool actuating system for a boring mill utilizing hydraulic servo power actuation and control for effecting the desired feed rate or rapid traverse movement, and stopping and starting of the tool movements.

A still further object is to provide, in a vertical boring mill, a hydraulic servo tool actuating system which receives its initial control power from the main source of power for actuating the work table.

And still another object is to provide an improved feed and rapid traverse control for a hydraulic servo operated tool actuating system.

It is also a further object to provide in conjunction with a hydraulic servo operated tool actuating system a Vernier hand adjustment for accurate positioning of the tools in desired operation positions.

A further object is to provide a machine tool of large capacity which requires a minimum of floor space.

And an object is to provide exceptional ease of operation for a machine tool of large capacity.

And still another object of this invention is to incorporate a hydraulic servo operated feed and rapid traverse power transmission for the tools of a boring mill in the cross rail of the machine 8 Claims. (01. 29-26)v I and to operate the apparatus from the main source of driving for actuating the work table.

Further features and advantages of this invention will appear from the detailed description of the drawings in which:

Figure l is a front perspective view of a vertical boring mill incorporating the features of this invention.

Figure 2 is a plan view of the boring mill, partly in section on the line 2--2 of Figure 1.

Figure 3 is a front elevation of the feed rate and direction control levers on each end of the cross rail.

Figure 4 is a fragmentary left-hand end ele- 5 vation of the feed and rapid traverse control box mounted on the rail as indicated by the line 44 in Figure 1.

Figure 5 is a fragmentary section on the line 55 of Figure 1 showing the main source of drivingv power for actuating the work table and the pow-er take-off for operating the hydraulic servo tool actuating and control mechanism.

Figure 6 is a fragmentary section on the line 6-fi of Figure 1.

Figure 7 is a vertical section on the line 1-'! of Figures 1 and 2.

Figure 8 is a vertical section on the line 8--8 of Figures 1 and 2.

Figure 9 is an enlarged section view on the line 9-9 of Figures 1 and 1 1.

Figure-10 is an enlarged fragmentary section through a tool bar hydraulic servo control valve on the line lfl-l ii of- Figure 1.

Figure 11 is a diagrammatic section on the line llll of Figure 9.

Figure 12 is a fragmentary horizontal section on the line iZ-ll? of Figure 1.

Figure 13 is a section through the cross rail and actuating cylinders for the saddles on the line Isa-l 3 of Figures 7 and 8.

Figure 14 is an enlarged view of the gearing shown. in the direction indicated by the line i k-M in Figures 6 and 11.

Figure 15 is a hydraulic circuit diagram associated with the tool control mechanism.

In modern machine tools, it is necessary to effect the control of the various movable machine elements with a high degree of accuracy and a minimum of physical effort required on the part of the operator in order to produce work of the desired high standard. This problem is particularly difficult' in large heavy-duty machine tools because of the necessary great Weight and sturdiness which must be built into the machine elements to produce the desired accuracy and smooth finish on the work piece. Also in such modern machines, closer tolerances must be maintained between the various moving members of the machine such as the slide ways, bearings, and other relatively movable machine surfaces to obtain the desired high accuracy. As a result, former practices of direct mechanical actuation of the various machine members have been found impractical and unsatisfactory because of the large amounts of power and effort required on the part of the operator in making machine adjustments. It is therefore the purpose of this invention to minimize the efiort required to operate the machine while providing the necessary great accuracy and nicety of control essential to a modern day machine tool.

As an example of a large machine tool of a heavy-duty type which this invention is particularly well adapted, there is illustrated a large vertical boring mill having a base 20, Figure 1, upon which is rotatably mounted the work table 2|. On each side of the rotary work table 2| and rigidly secured to the base 20 are the upright column-s 23 and 24 which are interconnected for rigidity by a suitable tie bar 25. On suitable guide ways 26 and 21 on the respective columns 23 and 24 is the vertically movable cross rail 28 which has horizontally extending guide ways 29, Figure 8, upon which is slidably mounted the saddles 30 and 3!. These saddles carry swivel slides 30a and Ma upon which are slidably mounted the respective tool bars 32 and 33 on suitable guide ways 34, Figure 2, formed in the swivel slides.

Work table drive The main driving power for rotating the work table 2! and for controlling the operation of the tool feeding devices is derived from a suitable prime mover or main drive motor 35, Figure 5, mounted on a suitable bracket 36 attached to the rear portion of the base 20. This motor which is preferably of a variable speed type, has a pinion 3! driving through a train of reduction gears 38, 39, 40, and M, the main input power Cross rail elevating mechanism The cross rail 28 may be adjusted up and down to any desired position on the columns 23 and 24 by means of a suitable elevating mechanism which derives its power from an electric motor 48, 25. This motor drives a worm 49 which actuates a worm wheel 50 fixed on the shaft extending toward each column 23 and 24 where it is suitably journaled in the bevel gear boxes 52. The shaft 5! carries bevel gears 53 fixed on its ends which in turn engage mating bevel gears 54 fixed to suitable elevating screws 55 journaled against axial movement in the columns 23 and 24. Each of these screws operate in nuts 56, Figure 8, which are rigidly attached to the cross rail 28 so that by appropriately energizing the motor 48 for r0- tation in one direction or the other the cross rail may be moved up and down to any desired position.

Figures 1 and 8, mounted on the tie bar Referring particularly to Figure 2, the rail clamping device which binds the rail in the desired selected position on the columns comprises a pair of opposed pistons 51 and 58 carried in a suitable cylinder 59 rigidly mounted on the cross rail 28. Each of these pistons have associated piston rods 68 on the outer ends of which are carried the actuating cams 5! which have a straight side 62 parallel to the direction of piston travel which rests against rollers 63 journaled on suitable studs 64 fixed in the cross rail 28. The tapered cam surface '65 engages the roller 66 on the lever arm 61 which is fulcrumed at the point 58 and has an abutting connection 69 with the column clamp 10 which engages the dove-tailed surface H of the columns 23 and 24.

In this arrangement fluid pressure may be alternately applied between the pistons 5'! and 58 to effect unclamping or in the piston rod chambers of the cylinder to effect the clamping action. This may be accomplished readily by any suitable solenoid operated hydraulic control valve '12. When the solenoid '53 of the valve 72 is energized the valve connects fluid pressure from a fluid pressure pump '14, Figure 15, driven by a suitable motor '85 through the pressure lines 16 and branch line lfia to the chamber between the pistons 51 and 58 while the piston rod chambers behind these pistons are connected by the valve at this time through the line Ti to the drain line l8 which is connected to the fluid reservoir or tank '59 to effect unclamping. When the solenoid i3 is ole-energized, the valve assumes a position wherein pressure from the lines I6 and 16a is now connected to the piston rod chambers while the drain lines Ti and is are connected to the chamber between the pistons for returning fiuid to the tank to thus effect the clamping of the cross rail to the columns.

Hydraulic servo drive mechanism The actuation and movement of the tool feeding devices comprising the saddles 33 and iii and their respective tool bars 32 and 33 is accomplished by hydraulic fluid pressure means under servo control. The hydraulic servo control mechanism is actuated by mechanical power from the main drive motor 35, Figure 5 Power take-off from this motor comprises a bevel gear in mesh with the bevel gear 44, this bevel gear being fixed on a suitable shaft 8! journaled in the base 29 upon which is also fixed a bevel gear 83, Figure 1. This bevel gear 83 in turn drives a bevel gear 84 fixed to a horizontally extending drive shaft 85 journaled in the base 25 of the machine and extending parallel to the cross rail 28 outwardly to each end of the machine. On the ends of this shaft 85 are provided the bevel gears 85 which in turn drive mating bevel gears 81 fixed to a vertical drive shafts 88 journaled at their lower ends in brackets attached to the base 20 of the machine and journaled in support brackets 89 fixed to the upper portions of the columns 23 and 24, these shafts serving to drive the feed control mechanism for the saddles and tool bars.

Feed and rapid traverse control On each end of the cross rail 28 is provided the feed and rapid traverse control mmhanism for operating the hydraulic servo device for the saddles and tool bars. The saddle 35 and its tool bar 32 are controlled in feed and rapid traverse movements by control mechanism mounted on h l t-hand endof. the cross rail while the saddle 3t and: its tool; bar 33; are; con-trolled bythe apparatus on the righthand end of the cross rail. Since: the, mechanisms at each end: of; the cross: rail are; substantially identical for operating their-respective saddlea .d tool bar, it is sufficient. to describe in detail but one of; these arrangemerits.

Taking for example the feed and rapid tray-- ervse control unit on the end of the cross rail indicated generally at 98; power from the shaft 88. associated with the column 23 is transmitted to bevel gear BI, Figure 11', jcurnaled in; bracket 92 fixed to the cross rail 2'8,v this bevel gear having a sliding driving connection with the shaft 88 so that it may be driven at all times for any' vertical position of the cross rail onthe columns. The bevel gear 91 in turn drives a bevel-gear fitfixed on the input-drive shaft 94; of. the feed and rapid traverse feed selector unit 95 fixed to the rear face 95o, Figure 12, of the lefthand end of the cross rail 28.

They shaft 94', in addition to being supported in a suitable bearing as. in the bracket 92, is also journaled on suitable bearing 9'! and 98in the feed selector unit 95. On the shaft 94 is mounted the driving disc 98 so as to be at all times driven by the shaft. 94 While it may be shifted axially thereof. A second shaft IBIS is journaled on suitable. bearings Ill! and I92 coaxially with the shaft 94, this shaft carrying a friction dis: Hi3, similar to that. of the discv 99, which is adapted to drive the shaft I Bil while it may be adjusted axially of the shaft I00.

Noting particularly Figure 9, both of the friction discs 99. and I03 are engaged simultaneously by a pair of friction plates I04 and W5 held in friction rolling contact therewith by a suitable compression spring I06 engaging by suitable means the .i'ournaled bearings it! upon which the discs I04 and I05 rotate about the shaft I06 mounted in the unit 95. Each of the friction discs 99 and its are interconnected for simultaneous shifting movements radially of the discs Iiii and H35 by means of the shifter yokes I89 and II!!- fixed to the shifter rod IIi slidably mounted in the unit 95 so that axial movement of, the rod. III simultaneously varies the radial, position of the friction discs 99 and IE3 with respect to the, plates I M and I 05 to effect infinite variations of speed in the shaft I510.

Power take-off from the shaft I'M is transmitted through the gear NZ to a gear H3 fixed to a shaft IM journaled in suitable bearingsv H5 in the unit 95. in keyed driving relationship. therewith is a compound gear I i6 having a large gear III and smaller gear I I8 which may be alternately engaged with the respective mating gears H9 and I25) fixed to a shaft IZI journaled in suitable bearings 22 in the unit 95. In this way, by shifting the compound gear M6 on the shaft H4; two ranges of speed may be effected in the shaft I25;

Power from the shaft I2! is transmitted by the gear IE9 toa gear E23 journaled on the feed and rapid traverse clutch shaft 52-4 journaled in suitable bearings I25 in the unit 95. This gear I23 may be connected in driving relationship with the shaft I26 or disconnected therefrom by means of the feed clutch I 26 which is operated by a suitable shifter spool IZ'I. In this way; feed driving speeds may be applied to the shaft I24.

The shaft I24 may also be actuated at rapid traverse speed from a rapid traverse drive motor I28, Figure 4, suitably mounted on the unit 95 Slidably mounted on the shaft, U4

andhaving a motor pulley I29 over which operates a suitable belt 430 which in turn drives a pulley I3I of the rapid traverse clutch I32, which is independently mounted to prevent rotational drag on the output shaft il but: carried in axial alignment therewith. The rapid traverse clutch 532 may be actuated by its shifter spool I33 for connecting ordisconnecting this rapid traverse driving power from the motor I23 to the shaft I214.

In this arrangement, the feed clutch I25 and the rapid traverse clutch I32 are alternately operated to connect the respective feed and rapid traverse power, to the shaft I2 by means of the shifter yokes 63d and I35 respectively engaging the shifter spools i2l' and i113, both of these yokes being; fixed on the shifter rod i323. so that a single operating lever ill may serve to disengage feed power and rapid traverse power to engage the feed power While retaining disengagement of the rapid traverse power, or engage rapid traverse power while maintaining disengagement of the feed power.

Power output from the shaft is transmitted to the servo mechanism for the saddle through a pair of gears it? and ass fixed on the shaft l24. A slidable gear I39 mounted in driving relationshipon, the saddle output shaft are may be directly engaged with the gear, It?! to drive the shaft I48, in one direction of rotation. The shaft Hi0 may be driven in the opposite direction of rotation by engaging the gear I35 with a geari li of the double gear I42 journaled on a suitable shaft I ifia in the unit 95, Figure 9, the other gear I143 of the double gear being in mesh with the gear 138' of the shaft It'd.

Similarly, the output shaft I i-d for the servo mechanism for the vertical movement of a tool bar may be connected to be driven in either direction from the shaft 824 by a gear Hill mounted in sliding driving relationshio on shaft 344 for alternate engagement with the gear ifs'l on the shaft 24 or with gear Mi of the double gear M2.

There has thus been provided mechanism for stopping and starting and reversing either of the output shafts i l-ll or lid for the respective saddle and tool bar servo mechanisms. There has also been provided a slow feed drive or a rapid traverse drive rate to the output shafts Md and I44. A range of speed change for the feed drive to the shafts I 46 and Hi l is also provided by the shifting of the compound gear Ilii. Furthermore, there has been provided an infinitely variable feed rate change for the output shafts I ti! and I4, I by adjusting the friction discs 93 and I83 as described.

Control levers and indicating dials In order to, effect the infinitely variable feed rate change, the shifter rod l i 5, Figures 1, i, and 9, is moved axially by means of its threaded portion lilo which operates in a nut Mi; suitably journaled against axial movement in a bracket of the feed selector unit 95. The nut Mi: may be appropriately rotated by means of its integral bevel gear is? which is engaged by a mating bevel gear I 38 carried on the control knob shaft Hi9 journaled in unit and having on its outer end an operating knob 6543 so that rotation of the knob rotates the nut ME and thereby adjusts the friction discs 98 and 03 to effect the infinite variations in feed desired.

The feed range selection is made by means of the control lever 55!, Figures 1, 3, and 4, which is carried on a suitable rock shaft I52 journaled in the unit 95 connected through suitable linkage I53 to a shifter rod I 4 slidably mounted in the control box 95 and to which is connected the shifter yoke I55 engaging the compound gear H6. When the lever is moved to the position I5Ia, shown in Figure 3, the gears H8 and I20 are brought into mesh for a fine range of feeds, and when the lever is moved to the position I5Ib, Figure 3, the gears H! and I99 are engaged for the coarse range of feeds.

Associated with the infinitely variable feed control knob I55 and the feed range control lever I5! is an indicating dial which at all times shows the exact rate of feed selected. This indicating dial comprises a disc I55 which is journaled on the knob shaft M9 and is driven at a reduced speed relative to the rate of rotation of the shaft M9 by its knob 250 by suitable reduction gearing comprising a pinion I51 fixed to the shaft I49 driving the large gear I58 of the compound gear I59 journaled on a suitable stud I55 fixed in the unit 95. The smaller gear lBI of the compound gear I55 in turn drives a gear I 62 fixed to the dial I53.

On the dial i56, Figure 3, is an indicating pointer I63 which cooperates with graduations I6 3 provided on a ring I65 fixed to the outer face of the unit 95. The relationship of the pointer 53 to the graduations I64 when the control lever is in the coarse range feed position I5I b, Figure 3, directly indicates the feed selected. When the lever l5! is moved to fine range position I5Ia, a pointer I66 on the ring I65 fixed to the unit 95 is associated with the fine feed range indications IE? on the rotating dial 956 so as to indicate the fine feed ranges selected by the control knob I50. By providing the control knob I55 with a selflocking feature, the sensitivity of the control is enhanced and by operating the indicating dial E56 at a reduced rotational speed relative to the knob I55, the entire feed range is brought to within a single revolution of the dial, thereby permitting reading directly the amount of feed per revolution of the table.

There has thus been provided an indicating dial device comprising fixed graduations on the machine frame and a rotating dial having graduations cooperating with a pointer on the machine frame for indicating one range of feed selection and having a pointer on the rotating dial cooperating with the fixed graduations on the machine for indicating another feed range selection.

The direction and stopping and starting of the saddle movement is accomplished by appropriately shifting the gear I39, Figure 11, by means of the saddle control lever I58, Figures 1, 3, and 4, carried on a rock shaft I69 appropriately journaled in the unit 95 and connected through suitable linkage Illl to the shifter rod Ill slidably mounted in the unit 95 and upon which is fixed the shifter yoke Il2 appropriately connected to.

the gear I39. The lever I68 when in the position i63a causes the gear I39 to engage the gear I4I When the shaft I24.

8 to move radially inward toward the work table axis.

The tool bar vertical movement control lever I73, Figures 1, 3, and 4, is mounted on a suitable rock shaft I'M in the unit 95 and is connected by suitable linkage I and shifter rod I'I5a to a shifter yoke I76, Figure 9, which is connected to the gear M5 so that when the lever I13 is in the position II3a, the gear I45 will be in mesh with the gear I3'I to cause the shaft I44 to rotate to drive the servo mechanism to effect upward movement of the tool bar. When the lever is moved to the stop position II3b, the gear I45 Will be positioned in neutral as shown in Figure 11. And when the lever I13 is positioned at I730, the gear I 55 will be in mesh with the gear [M to effect downward movement of the tool bar. Thus the control levers I68 and H3 serve to control the direction and stopping and starting movements of the saddle and tool bar.

The feed and rapid traverse movement is effected by means of the control lever Ill, Figures 1 and 9, which is connected by a suitable lever arm I18 to a rock shaft H9 journaled in a depending bracket lBG carried on the unit 95. The rock shaft has a lever arm I BI connected to actuate the shifter rod I36 which simultaneously alternately engages the feed clutch E or the rapid clutch I32 or to render both of said clutches inoperative. This control lever has a rapid traverse position I'I'Ia in which the shifter rod I is moved to the right, Figure 11, to disengage the feed clutch I23 and engage the rapid traverse clutch I32 to effect rapid traverse rotation of the When the lever is moved to an intermediate or neutral position, I'I'Ib, both feed and rapid traverse clutches I26 and I32 are disengaged so as to arrest rotation of the shaft I24. When the control lever I'II is moved to the feed position l'l'Ic the rapid traverse clutch I32 is disengaged while the feed clutch is engaged to effect the slow speed drive to the shaft I24.

In this arrangement of the simultaneous control of the feed clutch and the rapid traverse clutch, the operator may rapidly move the control lever I'll through the neutral position in either direction to substantially instantly start or stop the rapid traverse or feed movement so as to effect a high degree of accuracy of control in instituting or stopping the rapid traverse and feed movements. He may also independently with this same lever I'I'I connect or disconnect feed motion independent of the rapid traverse motion or he may readily effect rapid traverse movements without instituting feed movements.

There has thus been provided a control mechanism for a hydraulic servo operated tool feeding system which incorporates an infinitely variable feed change and a range change for the feed drive, a direction and stop and start control, and a means for simultaneously or independently con-,

trolling the feed and rapid traverse movements of the servo operated mechanism. This feed and rapid traverse control provides, through the operation of the single lever I'I'I, a constant speed of rapid traverse movement for rapid advance of the tool in the same directionas selected for feeding and independent of the speed of the feed setting. And it is to be further noted that since this control is driven from the main drive for the work table, the feed per revolution of the work table is maintained constant for any speed of rotation of the work table. 3 l

Servo screw and valve mechanism Power for actuating the servo screw and valve mechanism for the horizontal'movement oi the saddle along the cross "rail comprises a power take-off gear 182 -'fixed on the shaft IM, Figures 6, '11, and 14, which drives an idler gear I 83 journaled on a suitable stud I84 carried in the cross rail 23. This idler gear in turn drives a gear I85 journaled on suitable bearings I85 and I81, Figures 6, 7, and 12, in a suitable bushing I 88 fixed in the rail 2 3. 'Mounted for limited axial movement in the bore IBEao'f the gear 1 85 and adapted tobe'drivenby the gear I85 through 'a-suitable key Iii? is a bushing I99 which is fixed to the servo operating screw it! by a suitable pin I92 so that the screw may be rotated from the gear I 85 while allowing it a certain limited amount of axial movement relative to the gear and cross rail.

The-servo screw Iii-I ,Figures 'G and 12, serves to control the movement of the saddle 3-! and is j'ournaled in a bushing I93 in the gear I85 and is also supported in another guide bushing I94 fixed in the saddle M. A nut I9? is also 'fixed in th'e saddle and is arranged in threadedengagement 'with the servo screw 'IBI so that rotation of the screw in the nut I95causes this screw'to move axially relative to the saddle 3-I.

The saddle 3! actuated by 'a fluid pressure cylinder comprising the sleeve 1%, Figure 14, rigidly mounted in the cross rail 28 so as to provide an integral rigidifying tubular member for the cross rail at its 'end portions where greatest strain and bending moments take place. The cylinder has a piston I91 -to-Which is connected a piston rod I98 rigidly connected to the saddle 3| by suitable fastening nuts I99 at a point lying alongside of the other cylinder I9'Ia so as to keep the over all length of the cross rail just long enough to accommodate the required extreme outward movement of the saddles 30 and 3 1.

Control'of fluid pressure to the actuating lcylinder I36 for the saddle 3I isprovided by. the servo control valve 203, Figures'fi'and 15, which receives pressure from the pump 14 through the line it which is connected to the main pressure port 2M of the servo control valve 2%. Ports 202 andiil of the'servo valve 288 are-connected to the return or drain line 18 while the ports 204 and 295 of the valve Zlldare respectively-connected to the piston head chamber 10 i and the piston rod chamber 201 of the saddle actuating cylinder I953.

The plunger 208 of the servo -valve 200, which a is connected to move axially with the movement of the screw ISI, is provided with suitable annular gIOOVES 209 and 2 I 0 of conventional servo valve arrangement which cooperate with the above recited ports to function as a reversing and rate of flow control valve as the plunger 208 is moved axially either side of the neutral position shown in Figure 6.

Assuming the saddle 3I to be stopped with the servo valve plunger positioned in "neutral as shown in Figure6, when power is applied to the gear to'rotate the screw I9 I, the screw will tend to be moved axially in one direction or the other, depending upon its direction of rotation, by its interaction with-the nut'SS in the stationary saddle 3!. However, as soon asthe screw thus begins to move an appreciable distance axially, the servo valve-plunger 2B8'wi1l also thus be displaced from its neutral position and will'causelfluidto beapplied to the actuating cylinder I96 in such a manner as to cause the saddle to move in oppo site direction to the screw movement to bring the screw and the valve plunger 208 back to its neutral position. This automatic feed-back move ment, which is typical of servo control mechanisms of this type, continues so long as there is relative axial adjustment of the screw FBI in the nut I relative to the saddle 3! This feed-back movement may take place in either direction depending upon the direction of rotation of the screw by the driving transmission as effected by shifting the gear I39, Figure 11, as described.

Thus, in this way, relatively small driving forces for rotating the servo screw I99 may effect powerful and accurate control through the actuating cylinder 95 for the saddle SI. A similar arrangement of a hydraulic actuating cylinder i'ilfia having a piston I 91a and a piston rod IBM-connected to the saddle 30 at a point alongside the cylinder I98 serves to control the movement of this saddle by a suitable servo screw Ifiia and servo valve 200a as in the case of the saddle iii. The servo valve 200a is supplied by the pressure line 16b from the pump Ma and the drain line 18a appropriately connected by suitable lines 295a and 204a to the cylinder I98a.

Hand adjustment for the manual setting and accurate Vernier positioning of the saddles so and 3! is provided by the hand wheels '2! i, Figures 1 and 12, which are journaled for free rotation on a shaft 2 I 2 journaledon suitable bearings 2 I3 in the bracket 2M fixed on the saddles. The hand wheel may be clutched to the clutch teeth 2| 5 of the clutch sleeve 2 I i3 fixed to the shaft 1H2 so as to rotate this shaft and a bevel gear 2i? 'fixed on its inner end which engages the mating bevel gear 2I8 carried on suitable bearings are against axial movement in the saddle Iii. The bevel gear 2l8 is provided with a keyed bore to permit axial-sliding 'of the screw when driven by rotation of the hand wheel 2! I. A compression spring ZZ'Ilserves to'normally disengage the hand wheel 2'I 'I from the clutch sleeve ZIS so that it will'not'r'otate when the servo screw iSI is being driven by the power feed or rapid traverse drive.

The same mechanism shown in Figure 12 is utilized for the left-handsaddle 3i! and will therefore need no further description in that connection.

It 'is to beclearly noted that the cross rail arrangement, including the hydraulic actuating cylinders for moving the saddles 3t and iii thereoiil, is of unique'andnovel construction. Hereto'fore, lt' ha's been considered impractical to provide direct hydraulic actuation of the saddles on the cross "rail of aborin'g mill due to necessary space limitationsand structural rigidity required in the boring mill. Applicant, however, by a unique arrangement of "the essential hydraulic operating and controlelements for the saddles on the rail, has provided a rail structure which requires no more floor space than in conventional mechanically actuated machines and which rail need only be'longenough to accommodate the actual maximum movenient of "the saddles to their outermost positions relative to the work table axis.

In order to accomplishthese desirable results with hydraulicactuation of the saddles, the cylinders 196 and IS'Ba, Figure 13, are arranged in an overlapping manner so that their respective piston rods operate alongside of the respective oylinderswhere they are connected to the saddles 30 and "3| as best seen in Figure 13. It is to be noted that-these cylinders are spaced one above the other,'Figures 7 and 8, so as to provide a mini- 11 mum of outward overhand for the rail and saddles with respect to the columns to thereby increase the over all rigidity of the tool holding structure.

Another important feature of this arrangement is that of mounting the cylinders i9 5 and !96a directly in the rail casting. The object of this arrangement, in addition to minimizing the over all dimensions of the rail, is to provide steel tubes serving as the actuating cylinders for the saddles which also act to add rigidity to the rail at each end where the greatest bending movement and strain are present in the rail under operating conditions. Thus, in this unique arrange ment of staggered or overlapping cylinders, with cylinders mounted integrally with cross rail casting, a minimum of space is required for the ma chine while at the same time providing great rigidity in the cross rail.

The drive for actuating the vertical servo control valves 22! and 222 for the respective tool bars 32 and 33 is derived from the output gear 223 fixed to the shaft !44, Figures 6, 11, and 14, which in turn drives an idler gear 224 appropriately journaled on the stud H34 fixed in the rails 28. This idler gear in turn drives a gear 225 fixed on a shaft 226 journaled in the rail 28. A bevel gear 22? is journaled against axial movement in the saddle 3! and surrounds the shaft 226 in driving engagement therewith and axially slidable there along upon movement of the saddle along the cross rail. The bevel gear 22'! in turn engages a bevel gear 223 having a spur gear 228 attached thereto and journaled on a suitable stud 230 fixed in the saddle 3!. gear 255i fixed on a shaft 232 journaled about the center of swiveling of the swivel slide 3 In which is held to the saddle 3! by appropriate bolts operating in the T-slots 234 in a conventional manner.

0n the end of the shaft 232 is fixed the bevel gear 235 which in turn meshes with the bevel gear 235 fixed to the shaft 23'! journaled in the swivel slide 3m. The upper end of the shaft 23'! is provided with a gear 238 which in turn drives a gear 239 of the servo screw operating nut 240 journaled against axial movement in the swivel slide Sla. When the nut 240 is rotated by the gear 239 to axially translate the servo screw 24! relative to the swivel slide Bla, the valve plunger 242 for the servo valve 222, which is connected to the screw 24!, is moved axially as in the case of the plunger 208 of the valve 200, Figure 6. Pressure is supplied to the valve 222 from' the pump 74 through the line I6 and the branch line 243 while a return flow from the discharge ports 244 and 245 are connected to the drain lines 246 and it for return of fluid to the reservoir I9. Suitable lines 24'! and 248 are connected to the vertical cylinder 249 fixed in the swivel slide 3!a. A piston 25B is mounted in this cylinder and has a piston rod 25l connected to the bracket 252 which in turn is secured to the tool bar 33. A feed-back connection between the bracket 252 and the servo screw 24! and servo valve plunger 242 is provided by the 'arm 254 which is rigidly connected to the upwardly projecting rod 255 from the servo valve plunger 242.

This mechanism functions similarly to that of the mechanism described for actuating the saddles 3B and 3! except that axial movement of the plunger in the servo valve 222 is effected by rotating the nut 24!). The nut 240 has a suitable threaded portion 240a driving the nut and 00-. operating with the screw 24!, the portion 2401i having limited axial movement relative to the The gear 229 in turn drives a nut 240. The threaded portion 24071 is attached to the servo valve plunger 242 through which the screw 24! freely passes, the screw being rigidly attached to the bracket 252 of the tool bar 33 as described. Thus rotation of the nut 24!) causes axial displacement of the servo valve plunger 242 from a neutral position in that axial movement of the servo screw 24! as effected by rotating the nut 240 causes the valve plunger 242 of the servo valve 222 to be axially displaced from the neutral position, shown in Figure 10, to cause fluid pressure to be applied to the cylinder 249 to effect movement in the tool bar 253. The movement of the tool bar restores the valve plunger 242 to its neutral position through the servo feed-back linkage 254 as in conventional servo control mechanism of this type.

Similarly the tool bar 32 on the saddle 30 is controlled by the servo valve 22!, Figure 15, which receives fluid pressure from the line 16b and the branch line 256 and returns fluid through the drain line 251 through the line E8 to the fluid reservoir l9. Appropriate lines 241a and 24811 interconnect the servo valve 22! and the cylinder 249a so that operation of the servo plunger 242 by actuation of its operating nut 240a on the screw 24! a similarly effects movements in the tool bar 32, the feed-back control again taking place through a similar bracket 252a and arm 254a interconnecting the piston rod 25m and pislton 250a with the tool bar 32 and servo screw 24 a.

A manual Vernier adjustment of the vertical position of the tool bars may be effected by hand wheels 256, Figure 1, arranged to rotate the shafts 226 and 226a in the same manner as the servo screw I95 is manually rotated as described in Figure 2.

Operation The preferred manner of using the machine is as follows: The operator first mounts a work piece to be machined on the work table 2| by suitable clamps or chuck fixtures as is conventional practice in such machines. The hydraulic system of the machine is then put in operation by energizing the driving motor 15 for the fluid pressure pumps 14 and Ma. The rapid traverse drive motors I28 on the cross rail 28 are energized and put in continuous operation. Cutting tools, suitable to perform the desired machining operations on the Work piece mounted on the table, are placed in tool holders on the tool bars 32 and 33 in a conventional manner.

The cross rail 28 is then located in proper position relative to the work piece on the table 2! by energizing the solenoid E3 of the rail clamp control valve 12 to unclamp the rail from the columns 23 and 24. The rail elevating motor 48 may then be energized in one direction or the other for raising and lowering the rail to desired operating position. After the rail has been positioned, the solenoid i3 is again de-energized to cause fluid pressure to again clamp the rail to the columns as described.

The work table 2! is then rotated by energizing the main drive motor 35. The saddles 30 and 3! may each be independently moved relative to the work on the work table 2! at rapid traverse movement to initially bring the tools up to proper cutting position with the work piece by positioning the control levers !58 for the desired direction of in or out travel of the saddles and moving the feed and rapid traverse control levers IT! to positions H119 to initiate the rapid traverse -movement in the direction determined by the levers 468. The tool bars 32- and 33 carrying the cutting tools are positioned by rapid traverse movement in proper cutting relationship to the work piece by placing the control levers H3 in the correct position of direction of travel and operatin the feed and rapid traverse control levers H1.

Having thus initially brought the tools to proper initial starting position for a cut on the work piece, the operator then selects the desired feed-rate suitable for the material to be cut by adjusting the feed range control lever l5! and the infinitely variable feed adjusting knob [50 at each end of the cross rail 28'. Having thus selected the proper feed rate and having determined the direction of saddle or tool bar movement by positioning the respective levers I63 and I13 in the correct positions, the feeding of the tool over the work piece during rotation of the work spindle 2i. may be accomplished by moving the feed and rapid traverse control levers to feed position I170. The feed and rapid traverse movement may be stopped at any time by moving the control lever IT! to position, ill?) of neutral or nonmovement of the respective saddles'and tool bars relative to the work spindle 2|. The levers 68 and I73 may also be operated to independently or simultaneously stop or reverse the saddles and tool bars.

Thesaddles and tool bars may be fed manually by manipulating the control hand wheels 2! I and 256 when carefully controlled feeding conditions are required for feeding the tool up against a shoulder or abutment on the work piece. The indicating dials 2&3 serve to show to the operator the depth of feed and distance his tool has traveled relative to the work for effecting proper sizing of the finished machine work surface.

After the machining operations on the work piece on the table 21 have been completed, the operator may readily retract the cutting tools from the work by actuating the tool bars 32 and 3,3 and the saddles 30 and 3| in rapid traverse movements by appropriately positioning the control levers H3 and I58 in the direction of travel desired, and manipulating the feed and rapid traverse control lever I11 to the rapid traverse position I110. The main drive motor 35 may be tie-energized to stop thework spindle 2| for removal of the work piece and replace it with anew unmachined workpiece. To completely render the machine inoperative, the main drive motor 35, the hydraulic system fluid pressure pump motor [5, and the rapid traverse drive motors 128 are de-energized.

It is to be noted that the rapid traverse drive motor L28 may be continuously operated independent of the operation of the main drive motor 35 so that rapid traverse movement may be readily effected in the saddles and. tools for initially positioning them relative to Work even though the-work spindle is stopped and the main drive motor. de-energi-zedand the feed thereby rendered inoperative. Thus, the operator; may initially position his tools by rapid movement up to the work while the work is stationary for proper setting. of the tools with respect. to the work surface to be machined.

Considering the operation of the tool feeding devices in specific detail: When the operator wishes to eifect the horizontal crossfeeding of the saddles 30 or 3| to perform a radial facing cut, perpendicular to the axis of rotation of the work tablahefirst positions the saddle control l4 lever 168 in the position I680 if he wishes to feed inwardly toward the work table axis, or in the position 168a if he wishes to feed outwardly in a facing cut. Having thus positioned the saddle actuating lever in one position or the other for in and out feed and having positioned the tool bar control lever H3 in the stop position 1131), and assuming he has also appropriately adjusted the feed rate by manipulation of the control knob 58 and 15! as described for the character of the metal and nature of the cut to be taken, he may then institute the feed movement in the set direction at either feed or rapid traverse movements by operating the control lever ill to the Ella position for rapid traverse movement or to the position ll'lc for the feed movement. The

feed or rapid traverse movements may be stopped at any time by moving the control lever I'll to neutral. position. In this way, the horizontal radial facing cuts are made on the work by feeding the saddles along the rail into or away from the center of the work table as the work piece is being rotated thereby under the cutting tool can ried on the tool bar 33.

When it is desired to do turning or boring operations by the vertical reciprocation of the tool bar 32 or 3.3, the control levers for the saddle E58 are positioned in the neutral stop position I682) while the vertical. tool bar movements are controlled upwardly by moving the lever 173 from thestop position to the upposit'ion [13a or to the down position I130; Again the feeds selected for thevertical tool bar turning or boring movements are:- selected by appropriately adjusting the control,- knob i511 and its associated lever [5L Here again, the vertical feed and rapid traverse movements for the tool bars may be controlled under these conditions by again manipulating the control' lever I'H- to the position i'lla for rapid upward or downward movement, depending upon the settingof the control lever H3, or at feed movements in up and down direction. Thus, if the operator wishes to effect a downward turning. or boring out with the toolbar 33, for example, he positions theleve r H3 in the position H30 and then manipulates the feed and rapid traverse contro'l lever H-l either to the rapid traverse position I'Ha or to the feed position Il'lc. Likewise, the upward movements are similarly effected by repositioning the lever H3- up to" the position [13a and continuing the control of the tool bars in. upward feed and rapid traverse movements by the lever I17.

Thus, the operator has full selective control While the apparatusherein disclosed and described constitutes a preferred form of the inventio'n; it is'to be understood that the apparatus is capable of mechanical alteration without departing from the spirit of the invention and that such mechanical arrangements and commercial adaptations as fall within the scope of the appendant claims are intended to be included therein.

Having thus fully set forth and described this invention, what is claimed as new and desired to be-secured by United States Letters Patent is:

1. In a verticalboring mill having a frame, a,

rotary work table on said frame, and a cross fail on said frame associated with said work table, a pair of tool carrying saddles movable in facing feed movements radially of the axis of said Work table on spaced guide ways on said rail, hydraulic actuating means for moving said saddles in said facing feed movements comprising a pair of hydraulic cylinders rigidly mounted inside of said rail between saidguide ways to form integral strengthening members for said rail, pistons in said cylinders, piston rods, connected to said pis tons, each extending along the side of the other cylinder, and means connecting said piston rods to said saddles so that fluid pressure applied in said cylinders efiects said facing feed movement of said saddles on said rail.

2. In a vertical boring mill having a horizontally disposed CIOSs rail, a pair of saddles movable on guide ways on said rail in radial facing feed movement relating to the axis of said work table, a hydraulic actuating cylinder for moving each of said saddles in said facing feed movement each comprising a cylinder sleeve mounted inside of each end of said cross rail so as to provide an integral rigidifying member for said rail, piston and piston rod means operable in each of said cylinders, and means for connecting said piston rods to said saddles at a point in said rails between said guide ways alongside of said cylinders so as to reduce the over all length of said rail.

3. In a machine tool having, a rotary work holder, a cross rail, a pair of tool carriers movably mounted on spaced guide ways on said rail for radial facing feed movement relative to the aXis of rotation of said work holder, and fluid,

pressure actuating means for said tool carriers comprisin a pair of cylinders one mounted inside each end of said rail between said guide ways, pistons including piston rods operably mounted in said cylinders, and means including control mechanism interconnecting each of said tool carriers to be operated by one of said cylinders, said last mentioned means being located in said rail alongside each of said cylinders.

4. In a vertical boring mill structure including a cross rail, tool carrying saddles horizontally slidable in facing feed movement on guide ways on said rail, and fluid pressure actuating means for moving said saddles in facing feed movement comprising a pair of hydraulic cylinders including a cylinder sleeve mounted inside of each end of said rail for increasing the rigidity thereof, said cylinders having their axes lying in a vertical plane disposed parallel to the direction of facing feed movement of said saddles and located between said guide ways, and means including a piston and a piston rod in each of said cylinders connected to said saddles alongside of said cylinders so that the application of fluid pressure in said cylinders effects movement of said saddles. 5. In a vertical boring mill having a frame, a rotatable work table on said frame, and a cross rail associated with said work table, a pair of tool carrying saddles mounted on guide ways on said cross rail for facing feed movement radially of the axis of rotation of said work table, and means for actuating said saddles in facing feed movement and strengthening said rail comprising a pair of cylinder sleeves rigidly mounted one inside each end of said rail between said guide ways serving to rigidify said portions of said rail, pistons including piston rods operably mounted in said cylinder sleeves, and means located between said guide ways including control mechanism for operably connecting each of said piston rods to one of said saddles each side of the other 1'6 cylinder sleeve, and fluid pressure means connectable to said cylinders to effect movement of said saddles on said rail.

6. In a vertical boring mill having a frame, a rotary work table on said frame, and a cross rail on said frame associated with said work table,

a saddle movable on said rail in radial facing feed movements relative to the axis of rotation of said work table, a saddle actuating cylinder connected to move said saddle, a tool bar movably mounted on said saddle for longitudinal turning and boring movements parallel to said axis of the Work table, a tool bar actuating cylinder connected to move said tool bar, and a main drive motor connected to rotate said work table, the combination of a source of fluid pressure, a saddle servo valve interconnected between said source of fluid pressure and said saddle actuating cylinder, a tool bar servo valve interconnected between said source of fluid pressure and said tool bar actuating cylinder, and power means for reversibly selectively actuating said servo valves in feed and rapid traverse rates or to arrest their actuation comprising a feed rate changer driven A from said main drive motor, a source of rapid traverse drive power, a feed and rapid traverse clutch device driven from said feed rate changer and said source of rapid traverse drive power, a control lever for said clutch device operable to feed, rapid traverse, and neutral positions to effect feed and rapid traverse output from said clutch device or to arrest output from said clutch device, a saddle reversing clutch and a tool bar reversing clutch each connected to the output from said feed and rapid traverse clutch device, control lever means for each of said reversing clutches, and a mechanical drive connection from said saddle reversing clutch to the saddle servo valve and from said tool bar reversing clutch to said tool bar servo valve.

7. In a vertical boring mill having a frame, a rotary work table on said frame, and a cross rail on said frame associated with said Work table, a saddle movable on said rail in radial facing feed movements relative to the axis of rotation of said work table, a saddle actuating cylinder connected to move said saddle, a tool bar movably mounted on said saddle for longitudinal turning and boring movements parallel to said axis of the work table, a tool bar actuating cylinder connected to move said tool bar, and a main drive motor connected to rotate said work table, the combination of a source of fluid pressure, a saddle servo valve interconnected between said source of fluid pressure and said saddle actuating cylinder, a tool bar servo valve interconnected between said source of fluid pressure and said tool bar actuating cylinder, and power means for reversibly selectively actuating said servo valves in feed and rapid traverse rates or to arrest their actuation comprising a feed rate changer driven from said main drive motor, a source of rapid traverse drive power, a feed and rapid traverse clutch device driven from said feed rate changer and said source of rapid traverse drive power, a control lever for said clutch device operable to feed, rapid traverse, and neutral positions to effect feed and rapid traverse output from said clutch device or to arrest output from said clutch device, a saddle reversing clutch and a tool bar reversing clutch each connected to the output from said feed and rapid traverse clutch device, a control lever for said saddle reversing clutch having in and out and stop positions, a control lever for said tool bar reversing clutch having up 17' and down and stop positions, and a mechanical servo feed back drive connection from said saddle and tool bar reversing clutches respectively to the saddle and tool bar reversing valves.

8. In a vertical boring mill having a frame, a rotary work table on said frame, and a cross rail on said frame associated with said Work table, a saddle movable on said rail in radial facing feed movements relative to the axis of rotation of said work table, a saddle actuating cylinder connected to move said saddle, a tool bar movably mounted on said saddle for longitudinal turning and boring movements parallel to the axis of rotation of said work table, a tool bar actuating cylinder connected to move said tool bar, and a main drive motor connected to drive said work table, the combination of a fluid pressure pump, a motor for driving said pump, a saddle servo valve interconnected between said pump and said saddle actuating cylinder, a tool bar servo valve interconnected between said pump and said tool bar actuating cylinder, and power means for reversibly and selectively actuating said servo valves at varying rates of feed and at a rapid traverse rate or to stop actuation of said Valves comprising a variable feed rate transmission driven from said main drive motor, an independent continuously operating rapid traverse motor, a feed and rapid traverse clutch device connected to be driven from said transmission 18 and said rapid traverse drive motor, a control lever for said clutch device operable to feed, rapid traverse, and neutral positions for applying feed and rapid traverse output drive from said clutch device or to arrest output therefrom to a saddle reversing clutch and to a tool bar reversing clutch each connected to the output of said rapid traverse clutch device, and a control lever means associated with each of said saddle and tool bar reversing clutches operable to disconnect power from said feed and rapid traverse clutch device or to reversibly apply said power respectively to the saddle servo valve and said tool bar servo valve through a mechanical servo feed back drive adapted to actuate the respective servo valves.

OTTO E. SCHURR.

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

UNITED STATES PATENTS Kraut et al. Jan. 29, 1946

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