US2619854A - Control system for boring mills - Google Patents

Description

Dec. 2, 1952 o. E SCHURR 2,619,854

CONTROL SYSTEM FOR BORING MILLS Original Filed Feb. 25, 1946 3 7 Sheets-Sheet 1 2? Fl E 1 13 a 191 12w. 119 v INVENTOR. OTTO E. SCHURR ATTORNEYS Dec. 2, 1952 o. E. SCHURR 2,619,854

CONTROL SYSTEM FOR BORING MILLS Original Filed Feb. 25, 1946 7 Sheets-Sheet 2 54 INVENTOR.

OTTO E. SCHURR. BY

ATTORNEYS Dec. 2, 1952 o. E. SCHURR 2,619,854

CONTROL SYSTEM FOR BORI NNNNN LS INVE 0R 0 E.S URR. Q

T RNE Dec. 2, 1952 o. E. SCHURR 2,619,854

CONTROL SYSTEM FOR BORING MILLS Original Filed Feb. 25, 1946 7 Sheets-Sheet 4 FIG-4 INVENTOR.

OTTO E. SCHURR BY TM TJL...;-

ATTORNEYS Dec. 2, 1952 o. E. SCHURR 2,619,854

CONTROL SYSTEM FOR BORING MILLS Original Filed Feb. 25, 1946 7 Sheets-Sheet 5 INVENTOR.

OTTO E.SCHURR. F's-.6 BYTQ NT ATTORNEYS Dec. 2, 1952 o. E. SCHURR CONTROL SYSTEM FOR BORING MILLS Original Filed Feb. 25, 1946 7 Sheets-Sheet 6 VRW-VR-cu INVFNTOR OTTO E. scHuRR.

TAR; a T1.

REVERSINQ STARTER 4 Q 3 L \I F L L 7 a n m x o a m L 9 4 o 9 n I s M 1 O 4 5 A r R W z E E rl A 1 m w T A W P A W 4 a WA R R T o R L v 1 4 N 0 I n! am h r 4 c m 2 7 W W m m 5 A o o M 4 H T m w- P 0. T m 7 47. a m 4 w 5 FX 1 L -A- m 4-. m J 2 O A 2 2 \l f O P f O. 3 1H H 9 1 m 0 2 R .l. m 2 m x m r n" m m n T a? H :6 7 M 4 AER R 5 M 4 1 3 5 B I 2 1 :12 N. i i Q; v un A I- P H 4 H 2 Z 1- 1 AL S o T m m m 2 MANUAL STARTER ATTORNEYS Dec. 2, 1952 o. E. SCHURR 2,619,854

CONTROL SYSTEM FOR BORING MILLS Original Filed Feb. 25, 1946 7 Sheets sheet 7 INVENTOR 011-0 E. SCHURR a Mam ATTORNEYS Patented Dec. 2, 1952 CONTROL SYSTEM FOR BORING MILLS Otto E. Schurr, Hamilton, Ohio, assignor, by

mesne assignments, to Baldwin-Lima-Hamilton Corporation, a corporation of Pennsylvania Application February 25, 1946, Serial No. 649,920,

which is a division of application Serial No. 596,776, May 30,1945. Divided and this application December 1, 1948, Serial No. 62,847

3 Claims.

This invention relates to boring mills, and particularly to a car wheel boring machine.

This application is a division of Schurr application Serial No. 649,920, filed February 25, 1946, now abandoned, which, in turn, is a division of original Schurr application Serial No. 596,776, filed May 30, 1945, now Patent No. 2,445,498, issued July 20, 1948.

An object of the invention is to provide a car wheel boring machine that is automatic in operation for boring the journals of a car wheel.

Another object of the invention is to provide a. machine in accordance with the foregoing object wherein movement of the boring car actuates the control mechanism for regulating the speeds of movement of the boring bar of the machine, and wherein the speed of movement of the boring bar can be altered automatically to accomplish various turning operations during movement of the boring bar.

Still another object of the invention is to provide a boring machine in accordance with either of the foregoing objects wherein the boring bar is hydraulically operated and the flow of fluid to the boring bar isautomatically controlled to regulate the speed of movement of the boring bar in response to predetermined movements or predetermined positions of the boring bar.

A still further object of this invention is to provide a control system for a. car wheel boring machine or the like in which the boring bar is prevented from retracting following a cutting stroke until after the table supporting the work has been brought to a halt. v

It is also an object of this invention to provide a control system for a boring mill having rotary work table and a reciprocable boring bar in which the bar is prevented from engaging the Work in its cutting direction unless the table is rotating and is also prevented from retracting after a cutting operation until the table is halted.

Further objects and advantages will become apparent from the drawings and the following description:

In the drawings:

Figure 1 is a perspective elevational view of the car wheel boring machine of this invention.

Figure 2 is a transverse cross-sectional view through the machine illustrated in Figure 1.

Figure 3 is a transverse cross-sectional view of the mechanical control operated by the boring bar of the boring machine to control the cycle of operation of the same and is taken along line 3-3 of Figure 1.

Figure 4 is a cross-sectional view of the speed controlling device that is associated with the mechanical control illustrated in Figure 3 shown diagrammatically operably connected therewith.

Figure 5 is a partial cross-sectional view of the table of the boring machine showing :the mechanism for chucking the car wheel.

Figure 6 is a diagrammatic view of the hydraulic circuit for the machine.

Figure 7 is a schematic wiring diagram of a part of the control circuit for the machine.

Figure 8 is a schematic diagram of a second part of the control circuit showing the 3-phase power circuits to the electric motors.

Figure 9 is a cross-sectional view, partially in elevation, of the control valve for regulating the horizontal boring bar of the machine.

Figure 10 is an elevational view of the mechanism illustrated in Figure 9 and is taken along line I0--I0 of Figure 9.

Figure 11 is an elevational view of a part of the mechanism illustrated in Figures 9 and 10 and is taken along line I I--I I of Figure 10.

Figure 12 is a front elevational view of the control handle of the mechanism illustrated in Figure 9 and is taken as viewed in the direction of the arrow I2.

In this invention the boring machine consists of a bed I0 that supports a rotatable table II. The bed I0 supports a frame I2 that carries a vertical boring bar I3 and a horizontal boring bar I4.

The rotatable table II carries a plurality of chuck jaws l5 that are slidably supported upon the guide members I6 that extend radially of the table II along the upper face thereof. The chuck jaws I5 are adapted to engage and retain a car wheel I! in position to have work operations performed on it by the boring bars I3 and The horizontal boring bar I4 is hydraulically operated by a piston I8 that operates in a cylinder I9 carried in the frame I2. The piston I 8 is connected to the boring bar I4 by means of a connecting rod 20 and a connecting member 2 I. The boring bar I4 is carried in a cylinder 22 supported in the frame I2 of the machine.

The vertical boring bar I3 operates within a cylinder 23 carried in the frame of the machine. This boring bar I3 is hydraulically operated by means of a piston 24 operating within the cylinder 25, aconnecting rod 26 connecting the piston 24 with the boring bar I3 through the connecting member 21.

Hydraulic fiuid for operating the hydraulic motor 35 consisting of the piston 24 and the cylinder 25 is obtained from the pump 3| driven by the electric motor 32. The motor 32 also drives a hydraulic pump 33 through the gear box 34 which supplies fluid under pressure to the hydraulic motor consisting of the piston 18 and the cylinder IS.

The rotatable table I I is rotatably carried upon the support member 36 to carry the weight of the table, and is suitably journaled in the housing 37, the detail construction of which is more fully disclosed and described in Schurr application Serial No. 582,243, filed March 12, 1945, now matured as Patent No. 2,455,497. The table II is driven by a ring gear 33: that is supported upon the ledge 39. The ring gear carries a lug 40 that extends into an elongated opening 4la provided in the ring 4| rotatably positioned in the annular opening 42 provided in the table I 5.

Eachof the chuck jaws-15' carries a pin- 43 that extends into a guide member 44 positioned in elongated" cam slots 45" provided in the ring 4!. The radial movement between the ring M and the guide members 44- causes the chuck jaws l5 to move inwardly or outwardly, depending upon the direction of rotation of the ring M.

The ring 41 is-rotated' by the lug 48 carried on the ring gear 38 when the lug strikes either endof the slot a, this arrangement constituting a lost motion driving connection between the ring gear38 and the chuck jaws 15; Thus, movement of the lug 4-0 in a counter-clockwise direction as viewed in Figure" 5 causescounter-clockwise rotation of the ring H to move the chuck jaws I5 radially inwardly because initial movement of the ring 4| is relative to the table H since the table is stationary at this time. Conversely, clockwise movement of the lug 43 causes clock-- wise movement of the ring 41 tocause radial outward movement of the guidemembers 4'4 in the cam slot--45 and thus suclimovement of the chuck jaws 15 to unchuckthe car'wheel' at the end of the boring operation. The detail construction and operation of the aforementioned table construction is more fully disclosed and described in Schurr application Serial No. 582,243, filed March I2, 1945; now matured as Patent No.

The d'rive for the' table II consists of agearchange mechanism 'that is interposed between an electric motor 46 and the pinion 4?. The electric motor 46 drives the pulley 48 which in turn drives the input'shaft 49 0f thegear-change mechanism through meansofthe belts 5i and the pulley 52. The input shaft 49' carries a plurality of spur gears 53 54 and 55 splined upon the input shaft-49that are adapted to selectively engage the spur gears 56, 51', and 58, respectively, when selectively shifted into cooperating engagement therewith by the shifter 59'. The spur gears-"56; 51, and 513 are carried upon an intermediate shaft 60 that carries the spur gears 6 F and 62 adapted to; selectively engage the spur gears 63 and 64 when selectively; shifted into engagement therewithby the shifter'65; V The spur gears 63- and 64 together with the pinion 41 are carried upon the driven shaft 66'. The-pinion 41- is: carried onone endof the driven shaft 66. in meshing. engagement with the gear wheel 33 fordriving the same, the opposite end of the driven-shaft 63 being drivingly connected to: an electric generator 10 that is driven whenever the table H is driven, and which generator controls the chucking and unchuckingaction of 4 the chuck jaws IS in a manner hereinafter described.

When the table I l is to be stopped from rotation, a hydraulically actuated brake H is provided, the brake 7| being actuated by the hydraulic motor 12 that issupplied with fluid under pressure from the pump 13 driven by the electric motor 14, the details of which brake are more fully disclosed and described.

In the boring machine of this invention, a car wheel is placed upon the chuck jaws I5 upon the table H Thereafter, the main drive electric motor 46 is started for driving the ring gear 38 through the gear-change mechanism 53. The car wheel ll ischucked and centered by an alternate starting and slowing down of the main drive motor 45 in a manner hereinafter more fully described. After the car wheel is completely chucked, the vertical boring bar [3 is moved downwardly on a rapid traverse stroke until the rough boring tool; 15- approaches the car wheel l-l. As the rough boring tool 15 approaches the' car wheel [1, the boring bar [3 is advanced at a feed rate to produce the rough boring operation. Whenthe rough boring operation is complete, the speed of advancement of the boring bar i3 is again changed to a diiferent feed rate for moving the finishing boring tool 16 through the journal of the car Wheel for finish-boring the same, and finally the chamfer-ing tool Tl chamfers the edge of the car wheel journal, and the boring bar is brought to rest atthe end of its. downward stroke by an adjustable stop-rod '76. The spindle is then halted and the boringbar [3 is reversed in movement to cause arapid upward traversing of the boring bar to its top position wherein it stops until the operator again initiates another cycle of operation of the machine. The horizontal boring bar 14 then carries its facing tool 19 across the car wheel to face the hubaround the journal thereof, a suitable interlock being provided to prevent actuation of the bar M if the spindle'is notrotating.

A hydraulic apparatus for controlling the op eration of the verticalboring bar 13 and the horizontal boring bar 14 is diagrammatically illustrated in Figure G wherein the electric motor 32 drives the pumps 31 and 33* heretofore referred. to.

A speed control apparatus '85 for controlling the flow of hydrauliofluid from the pump 3 l' to the hydraulic, motor 351and' from. the hydraulic l'llOtOr3'5 to a reservoir is illustrated in Figure 4. The speed control apparatus consists of a valve body 81 that has a valve spool 82 reciprocable therein i'saninternal bore 83. The valve-body 8| has a plurality of passagestherein intercomheating the four ports 84, 85; 86, and B7; The port 85 is the pressure'inlet port from the pump 3|, and in reference to the" hydraulic circuit, Figure 6 will be referred to, that is connected to the port 85 by the conduit 88. The port 84'- is connectedto the upper end of the hydraulic motor 35 by the conduit 89 for moving the'boring bar IS on a downward stroke. The port 83 is connected to the reservoir tank 90' by a conduit sl to returnfluid under pressureto thetank from'the hydraulic motor 35- from one sidethere of when-fluid under pressure is admitted to the opposite side ofthe motor. Port 81 of-the speed control 8B isconnected t'o-the lower end-of the hydraulic motor 35" by mea'nsof a conduit 92 that has" therein a: check -valve 93 for allowing free flow of fluidiunder pressureto: the bottom side of the hydraulic motor 35 butrresists re'turn flow of fluid therethrough, at resistance valve 94 being provided in a by-pass line 95 around the check-valve 93 to insure a pressure in the lower end of the cylinder 23 during the downstroke of the boring bar I3 and prevent a free falling of the boring bar. A compensating valve 98 maintains a constant feed rate regardless of fluctuations in cutting tool resistance or changes in operating pressure.

The speed controller 80, or more specifically, the spool 82 thereof, has five positions vertically within the body of the speed controller for producing (1) a rapid advance of the boring bar, (2) a fast-feed rate for the boring bar, (3) a slow-feed rate for the boring bar, (4) a stop position, and (5) a rapid return for the boring bar. These positions are attained by the spool 82 moving through a full stroke from the top to the bottom of its movement.

When the spool 92 0f the controller 69 is in its first or top position, fiuid under pressure is delivered through the port 85, the passage I00, the passage IOI into the port 84 for delivery into the upper side of the hydraulic motor 35, the return fluid from the lower side of the hydraulic motor 35 being through the conduit 95 and the resistance valve 94, conduit 92 to the speed controller 80 and thence through port 61, passage I02, passage I03 and passage I94 to the port 86, and from thence to the reservoir tank by way of conduit 9I, thus causing a rapid advance of the boring bar I3. At this time the resistance valve '94 functions to maintain pressure beneath the piston 24 of the hydraulic motor 35 to prevent a free falling of the boring bar I3, the resistance valve overcomes the spring I06, whereupon conduit 95 is opened to the flow of fluid into the conduit 92 to by-pass the now closed check-valve 93.

Downward movement of the boring bar 13 subsequently causes movement of the spool 82 of the speed controller 80 in a manner-hereinafter described to change the rate of discharge of fluid under pressure from the lower side of the hydraulic motor 35, and thus change the speed of v movement of the boring bar I3 to obtain a feed rate movement thereof. Two such changes in feed rate can be obtained by operation of the speed controller 80. The first change is that previously referred to as the second position of the spool 82 for obtaining a rapid feed rate of the boring bar I3. At this time fluid under pressure is still being delivered to the hydraulic motor through the port 84 and the conduit 39, but the return flow of fluid from the lower side of the hydraulic motor 35 will be changed so that the fluid discharges through the conduit 95, the resistance valve 94, the conduit 92, the port 81 of the speed controller, passage I92, passage I01, pressure compensator 98, passage I98, metering valve 91, passage I09, passage H0 to passage I03 and then to passage I04 and tank port 86. This hydraulic circuit thus places the metering; valve 91 in circuit with the hydraulic flow from the return side of the hydraulic motor 35 to slow down the forward advancement of the boring bar l3 and give it a predetermined feed rate, which may permit a coarse feed or fast feed.

The movement of the boringbar I3 can then be given a second feed rate upon a movement of the spool 82 into its third position wherein the fluid under pressure is still supplied to the hydraulic motor 35 in the same manner as previously referred to and the fluid is dischargedfrom the lower side of. the motor through the previously mentioned conduits into the port 01 of the speed controller 80, and from the port 81 the fluid flows through the passage I01, pressure compensator 98, passage I08, metering valve 91, passage I09, through metering valve 96, passage I I I and then to passages I03, I04 to the tank port 86, thus placing the metering valves 96 and 91 in series flow relationship to further reduce the speed of movement of the boring bar I3.

When the boring bar is to be stopped, either in its upward or downward movement, the spool,

82 of the speed controller is moved into its fourth position wherein the ports 84, 85, and 81 are all connected to the tank port 86 to thereby by-pass the hydraulic motor 35, port 85 being connected to the tank port 86 through passage I00, passage I03 and passage I04, port 84 being connected to tank 05 through passage IOI, passage I03 and passage I04 and port 81 being connected to the tank port 85 through passage I02, passage I03 and passage I04.

When the boring bar is to be moved upwardly, the speed controller 80 may then have the spool 92 thereof placed in its fifth position wherein the fluid under pressure is then supplied from port 85 into port 61 through the passage I00 and passage I02 to deliver the same into the conduit 92 through check-valve 93 and into the lower side of the hydraulic motor 35, the discharge from the upper side of the hydraulic motor 35 being through the conduit 89 into port 84 of the speed controller 80 and through passages I9l, I03, and I9 3 into the tank port 83, and from thence to the reservoir 90, and thereby obtain a rapid return of the boring bar I3.

The speed controller 80 can be manually set in any one of the five positions referred to by the control handle H5, and is automatically set in any one of its positions by the rotatable cycle controller I I6 that is actuated by the boring bar I3.

The cycle controller II6, shown in Figure 3, consists of a substantially cup-shaped rotatable member I20 that is positioned Within a chamber I2I provided in the frame of the boring machine. The chamber I2I has-the side-wall I22 thereof suitably bored to receive the member I20 and form a bearing surface for the same, the member I 20 having the outer peripheral surface I23 thereof turned to fit within the bore I22. The bottom of the cup-shaped member I20 is provided with an extension I24 that is received within a bearing bore I25, the member I20 thereby being rotatably supported in the frame of the boring machine.

The member I 20 carries a ring gear I26 that is engaged by a pinion I21 carried upon a shaft I28 that is journaled in the bearing bore I29 provided in the frame of the boring machine and adjacent the boring bar I3. The shaft I28 carrie a spur gear on the end thereof opposite to the end that receives the pinion I21, the spur gear I30 beingsuitably secured or keyed to the shaft I28. The boring bar I3 is provided with a rack I3I that extends vertically along the boring bar to mesh with the teeth of the spur gear I30, and thereby rotate the spur gear I 30 upon reciprocation of the boring bar l3. Reciprocation of the boring bar I3 thereby causes rotation of the member I20 of the cycle controller I I6.

The member I20 is provided with an annular T-shaped slot I32 that is adapted to receive square-headed bolts I33 by which cam dogs I34, I35, I36, I31, and I38 are secured to the member I20. The bolts I33 may be inserted through aerasc r opening I39 provided in the member I20. The cam dogs I35 to I38 inclusive extend radially of the member I20 and are provided with cam surfaces on the outer edges thereof adapted to engage the roller I40 provided on the outer end of the spool 82 of the speed controller 80 forshifting the spool to the various positions aforementioned.

The cam dog I34 is adapted to actuate the limit switch LS that i provided in an electric circuit hereinafter described for the purpose of' energizing a timing element during a chamfering opera-' tion,-which timing element produces an actuation of electric controls for automatically causing operation of the speed controller 88 electrically to produce an automatic and rapid return of the boring bar when the speed controller 50 is placed in its aforementioned fifth position.

As illustrated in Figure 4, the cycle controller-is in position for placing the speed controller 80 in its aforementioned fourth position or stop position.

To initiate operation of the boring machine, the manual control handle I I5 of the speed controller 80 is shifted to move the spool 82' thereof into its first position, or rapid advance position, which is the top position ofthe spool. This movement causes flow of fluid under pressure to the hydraulic motor 35 through the aforementioned circuit for rapid traverse downwardly of the boring bar I3. The downward movement of the'boring bar I3 produces rotation of the member I20 of the cycle controller I I6 until the cam dog I35 engages the roller I40 of the spool 82 to move it downwardly into a feed position, and in the sequence of operation of this machine, the cam dog- I35 moves the spool 82 into its third position or slow-feed position. This occurs when the first boring tool I5 is ready to engage the journal of the car wheel- I'I. When the tool 15 passes through the journal of the car wheel, the second boring tool I6 is ready to enter the journal for a finish-boring operation. At this time, the cam dog I35 engages the roller I40 of the spool 82' to lift the spool from itsthirdposition toitssecond position, or fast-feed position. Tnefim; ishingtool I6 is then carried through the journalof the car wheel for the finish-boring operation.

Continued downward movement of the boring bar I3 continues rotation of the member I 20 of the cycle controller H, and-when the-chamferingtool TI approaches the hub W 0i the' carwheel IT, the cam dog I37 is-rea'dy" to engage the Continued downward movement of the boring bar I3 continues rotation of themernber I1 0 of the cycle controller H0, and when the'chamfering tool 11 approaches the hub' Hitof the car whee-l H, the cam dog I31 is ready to engage the'roller I40 of the spool 82- to again movethe-spool-from its second position to-its thirdposition-for'a slo'w-' feeding operation during the cha-niferin'g of the hub of the car wheel. a

When the chamfering operationbegins, the cam'dog I3-4'engages the actuating arm I41 of the limit switch LS which in turn energizes atimer thatsubsequently controlsa solenoid I45 upon completion of the timing operation to shift thespool 82 of the speed controller 2 into its-fifth or rapid-return position. The limit of down ward movementoftheboringbar I3 is controlled by the adjustable stop-rod 13 that has an adjust-i ing mechanism I49 for setting the upper'end of? 8 the stop-rod 18 to control the limit ofdownward movement of the boring bar I3;

When the solenoid I45 is energized, placingthe speed controller 80 into a rapid-return position, fluid under pressure is delivered to the lower side of the hydraulic motor to raise the boring bar I3, thus rotating the member I20 of the cycle controller H6 in a counter-clockwise direction; the aforementioned rotation of the" member' I'20 during the downward movement of the boring bar beingin a clockwise direction; As the boring'bar I3 approaches the upper end of its" movement; the cam lug I38 engages the roller I40 on thespool' 82 of the speed controller 80 to move the spoolfrom its fifthpositionto' the fourth or stop position, thereby halting upward movement of the boring bar I3.- Themachine then stops and the carwh'eel is unchucked in' amanner hereinafter described so that a new wheel can be placedin-position on the table I I and the machin'e again startedmanually for a boringoperation by move-' ment of the controlhandle I 15 of the speed controller 80; and the cycle hereinbefore mentioned is repeated. 7

After the vertical boring operation iscompleted,

ahorizontal facing operation can be made upon the face of the hub I 46 of the car wheel H by the boring bar I4 and the toolcarried thereby. This-operation is performed manually by shiftingthe position of the spool I5I- of the e-wayvalve I50; seeFigure 6. Fluid under pressure is supplied'from'thepump 33' through the conduit I52 to the -way valve I50 and thence through either of the service lines I53-or I54 for reciprocationof the piston I8 of'the hydraulic motor 30; which thus causes reciprocation of the boring bar I4.-

When fluid under pressure is supplied to either end of the hydraulic motor 30, see Figure 6, the discharge of fluid from the end of the hydraulic motor opposite that receiving fluid under pressure is conducted through a speed controller H0 consisting" of a pressure-compensating device I 55 andametering' valve I56 by way of conduit I51 before-the fluid is discharged into an exhaust line I58 to thereby control the speed of movement of the boringibar I4;

The operation of the boring bar I4- is' inter locked-with the operation of the main drive motor 45 of the boring machine by means of a by-pa'ss' control valve I00- that'is actuated by asolenoid I'GI so that when the solenoid is" energized dur-' ingthe period of time when the main drive motor is operating; the by-pass line IE2 through the valve I 50 will be closed and thereby'the' pump will develop pressure in the discharge line" I52.

However, should the main drive motor be stopped" for any reason, the spring I53 in the valve I60 will cause the by-pass line I02 to be opened for by-pa'ssing the pump discharge from the" pump 33 so that fluid under pressure cannot be sup plied te the hydraulic motor 30 to operate the boring bar I4.

The 4-way valve I 50 i'sactuated by a manually operable control rod- IH having an operating handle I12 that rota-testhe control rod I'I-I which,

through a bell-crank lever- I13 pivoted upon the pivot pin I'I4,'operates the spool I5Iof the 4-way valve I50. The ends ofthe bell-crank lever I-'I3-' engagea' y oke I75 on theend of the controlrod [TI and a yoke I76 on the 'end ofthe spool-con trcl rod I5'I; The speed controller I-is-located' adjacent the -i-way valve I50; see Figure-9, and-isprovided with a manually operable dial -I'I-l for setting: the metering valve I 56. r

The solenoid I6I for actuating the solenoid valve I60 is interlocked with the operation of the manual control handle I'I-2 so that the horizontal boring bar I4 cannot be moved at a feed rate unless the main driving motor 46 of the boring machine is in operation, but the boring bar can be manually traversed regardless of whether the main drive motor is operating should it be desirable, such as when setting up the tools.

This interlock is obtained by the use of an electric switch I80 that has one pair of normally closed contacts and a pair of normally open contacts, the electric switch being placed electrically in circuit with the solenoid I6I. The normally closed contacts are arranged in the electric circuit hereinafter referred to in such a manner that the main drive motor 46 must be energized and operating before current can pass through the solenoid I6l to energize the same to close the bypass valve I60. However, should the main drive motor be stopped, an actuating member I8I, see Figure 11, is provided in the end of the manual control rod I'II for engaging the actuating member I82 of the electric switch I80 to close the normally open contacts when the actuating handle I12 is moved with the pointer I83 thereof, see Figure 12, to the traverse position, at which time either of the cam projections I84 on the member I8I can close the normally open contacts of the electric switch I89 to energize the solenoid I6I and close the by-pass valve I60 so that fluid under pressure can be delivered to the hydraulic motor 30 for actuating the horizontal ram I4. However, the cam projections we are spaced apart a sufficient distance that when the manual control handle I12 is in either feed position, the switch I89 will not be actuated for 'closing'the normallyopen contacts, thus renderin the chuck jaws I to gradually bring the chuck b jaws into engagement with the drive wheel and center the drive wheel between the chuck jaws. After the chucking operation is complete, the

,main drive motor is operated at full speed and the boring operations previously described are performed upon the car wheel. At completion of the boring and chamfering operations, the boring bar is withdrawn and then the clutch jaws are unchucked in the same manner in which they were chucked.

The electrical system for performing the various aforementioned operations and the operation of the system as applied to the boring machine will be described together, special reference being made to Figures 7 and 8 which illustrate diagrammatically the electric circuit, Figure 8 being the specific 3-phase circuit for the electric motors.

To begin operation of the boring machine, the operator first starts the motor 32, that supplies hydraulic pressure in the hydraulic system shown in Figure 6, by depressing the pump starting push-button 200 which closes a circuit from power line L-I through the normally closed pump stop push-button 20I, the contactor coil OP, and the normally closed overload relay contacts for .of the generator I0.

motors I99 and 32, to the power line L-3. The contacts OP-I, OP-Z, and OP-3 of the contactor OP are thereby closed to supply current to the pump motor 32, and also to the lubricating pump motor I99. The contactor OP is held energized, after depressing the push-button 200, by contact OP-5, together with normally closed contact BM-5 and/or selector switch 2! marked Hand- Automatic when in the automatic position. The coolant pump motor I98 is manually started at any time. A stop push button 20I is provided for breaking the circuit through the contactor GP to stop the pressure pump motor when the system'is to be shut down.

After a car wheel is placed in position upon the chuck jaws I5, the chucking operation is started by depressing the chucking push-button 202, it, of course, being understood that the machine stop push-button 203 is closed at this time since all push-buttons used on this machine are of the momentary contact type. When the push-button 202 is depressed, relay I-R is energized by a circuit made from the power line L-I, through normally closed timer contact TA-I, through the stop push-button 203, the chuck push-button 202, normally closed contacts I A-4, relay coil I-R, now closed contactsOP-d (which closed when contactor OP was energized), normally closed overload relay contacts for motors I4 and 46, to the power line L-3. Relay I-R is held energized by its auxiliary contact IR-Z. Energizing of relay I-R causes energization of contactor I-F upon closing of contacts IR-I, contacts 3R-2 being closed at this time because relay 3R is energized in view of the normally closed contacts VRr-l that are now closed because of non-operation of relay VR. Contactor IF thereby closes contacts IF- I, IF-2, and lF-3 to supply current from the power lines L-I, L-2, and L-3 to the main drive motor 4'6, the current now being supplied through the resistors 204, 205, and 206 to reduce the voltage supplied to the motor 46 and cause the same to rotate at a low speed. Energizing relay IR. also caused the closing of contacts I R-5, IR-6, IRF'I, and IR-3 that energize the generator field 201 Since the generator I0 is driven by the main drive motor through the same shaft that drives the gear wheel 38 for producing the chucking operation, the voltage generated by the speed measuring generator I0 is proportional to the, speed of movement of the gear wheel 38 and thus proportional to the speed of the chucking operation produced by the chuck jaws I 5.

The relay VR associated with the speed-regulating generator has two coils, VR-a and VRb, the coil VRa being excited from a copper oxide rectifier 2H), through an adjustable resistance 21 3, a resistance 2I2 being provided" to by-pass current from the coil VR-2 when'normally closed contacts R-I, thereby supplying the major amount of current to the coil VRa of the relay VR. The coil VRr-a provides a certain amount of flux, but is insufficient to close the relay or to hold it in. Therefore, as the motor 46 accelerates, the voltage of the speed-measuring generator increases causing an increased amount of flux in coil VR b until the relay VR. picks up at a definite and predetermined speed. When the relay VR. picks up, contacts VR-I are opened thereby de-energizing relay 3-R to reopen contacts 38 -2 and thereby de-energizing contactor IF to open contacts IF-I, IF-2, and IF-3 to shut ofi the supply of current to the main drive motor 46. Simultaneous with opening of contactor IF, relay R is de-energized to close contacts R-I to byr-pass current from short-circuit .coil VR-a of relay VR to decrease the flux so that at the time the main drive motor has its current shut off and begins to coast, the combined flux in relay coils VR..a and VR.b is just slightly greater than that required to hold relay VR in the operated or closed position.

As the drive motor 46 now slows down, the flux in relay coil VR-b decreases until relay VR drops .out, thereby again closing contacts VR-J to reenergize relay 3 -R and thereby reclose contacts 3R4 to re-energize .contactor 1F and close contacts IFI, lF-2, and lF-3 to re-energize the main drive motor 46. This alternate acceleration and coasting .of the main drive motor 46 continues until the chucking operation is complete, atwhich time the chuck jaws I grip the car wheel 1'] and cause the table to rotate slowly.

"The operator now depresses the run pushbutton 2H which provides a circuit from the power line L-.-l through the closed TA-l contacts, stopsbutton 203, now .closed contact 1R4,

push button 2] l, relay coil 2R, closed contact 0P4 and closed. overload relay contacts [4 and 46, to the power line L-3. Relay 2R closes relay .contacts -2Rl and holds itself energized. Contacts 2R-i parallels contacts 3R-2 and IE4, whereby a circuit is made from the power line La! through the .contactor coil lFand reverse contactor interlock normally closed contact 5134 to the power line L-3 for closing contacts iF-I, ;IF.-2, and lF-3. Simultaneously with the establishing of this other circuit to keep contactor 1F energized, a parallel circuit is made through contactor .lA, contacts l-F-4 being now closed because of energization of .contactor IF, and relay contacts 2R4 having closed with re 'lay ZR. .Contactor lAcloses contacts lA-l, .lA-Z, and :IA-3 tony-pass the resistance 2134, 2 65, and 2116 so that full voltage from the power lines L4, L-2, and L-3 .can be supplied to the main drive motor 4.6 and bring the same up to full speed. An interlock contact lA-A opens when contactor .IA is energized .to .de-energize relay 1R. and thereby open contacts .lR- 5, lR-G, IR-I, and [Rf-.8 to de-energize the generator field 287, thus cutting out the efiect .of the generator on the operation of the electric circuit when the main drive motor 4.6 is operating at full speed.

The machine is now in condition for performing the boring operations as performed by the operation of the hydraulic circuit hereinbefore .disclosed and described. As previously mentioned, the last .operation .on the car wheel I] is the chamfering of the wheel hub I48, and the boring bar I13 is then stopped against the positive stop 18. When this occurs, limit switch LS is operated by the cam lug 13.4 to close contacts 1.6-! and open contacts LS-2. .Contacts LS-l energize a timer TA consisting of a solenoid coil TA, a synchronous telecron motor, normally closed time imit switch TA-2 and timer motor TM. The adjustable time limit switch with its normally closed contacts 'I'A-Z is mechanically opened by the motor and stays open until solenoid coil TIA is r e-ene d the t Tie-2 o ac l s immediately. At the expiration of the time periodof the timer TA, contacts TAvl are opened, thereby de-energizing the relay 2B. which in turn causes contactors H and IA to be tie-energized and thereby stop the operation of the main drive motor 4.6. As long as the main drive motor 46 is rotating, a centriiugally operated switch C keeps its contacts closed to maintain relay TR energized and thereby maintain contacts TR-l 12 closed and contacts open while the electric motor 46 continues to rotate.

When relay 2B, was de-energ-ized to remove the power source from the main drive motor t6, this caused contacts 2R4 ioclose thereby establishins an tri cir uit th ou h t e ntactor BM from the power line L--I through now closed eontacts TR-I, contacts R-B, Rf-4, 2B4, contactor coil BM to the power line L13. Contactor BM closed contacts BM-l, BM-2 and BM-j to start the electric motor 34 to drivethe pump 1 for supp y n fluid under p e u to the hydraulic brake H and thereby bring the table I l of the machine to ,aauick stop.

W t e table 9 the mac in st p and thus the main drive motor 46 stops, switch (5 is opened to ie-energize relay'IR and thereby a.;tter a short time delay opens contacts 'IfR-l to stop the brake motor and closes contacts for making a circuit through the electric solenoid I45 from the power line L-l through now closed limit switch contacts LS- l, contacts {IR-2 and solenoid hi5 to the power line L-3. Energizar tion of the solenoid M5 shit-ts the speed controller 30 to its fifth position to cause a rapid return of the boring bar J3 The controller is then mechanically placed in its fourth position to stop the movement of the boring bar when it reaches the top of its strolre. The limit switch LS was reset when the boring bar 13 moved away from its chamfering position.

If during the downward movement of the boring bar the stop push button 283 should be opened, relay 2R will be de-energized which in turn tie-energizes contactors IF and lA-to stop the main drive motor 46. However, regardless of the wn s t n o iheb rine bar i e h d auli motor '54 for actuating the hydraulic brake 1-! will be operated because at the time the main motor &6 begins coasting switch 0 being closed, d y beme ner ized i on act closed, thereby establishes a circuit through the contactor coil BM in view of the now closed contacts lR-4 and 23-4. When contactor BM is energized, contacts Bit/l4 are closed to establish a circuit from power line L-l through now closed contacts TPv-l, now closed contacts BM-4, contacts LS-Z and solenoid I 4 5 to the power line L-3, to immediately move the speed controller to its fifth position and cause a rapid return of the boring bar I3 This precaution is made to prevent a cutter from feeding into stationary work When using long boring bar tools for machining holes larger in diameter than the diameter of the boring bar [3, it is necessary to prevent t ut m c r tu n of t e borin bar to i normal starting position at the top of its strolge. When selector switch {M4 is turned away {rem its normal automatic position to the hand P931- tion, the hydraulic pump motor 32 will he stopped and oil pressure will drop to zero whenever the main drive motor starts to stop and the brake motor 14 is energized and opens normally closed contact BM-5.

With the boring bar 13 in the up position, the operator can now depress the unchuck pusht n 2- h ch energizes rela 4 t cueh no mally closed contacts IR-3, iorwardcontactor interlock, normally closed contact IF-B and relay coil 5R, to close relay contacts ,tR-l, 4R4, 4R,-3, and 4R-4 to energize the generator field in the opposite direction to that which was occasioned when relay ,i-R was closed. Relays VR, 3R and R operate in exactly the same manner as previously described for the chucking operation to control the speed of the main drive motor 46 in the opposite direction for the unchucking of the car wheel, except that the relay contacts 3R-3 close and open to energize and de-energize the reverse contactor 5R which close and open the contacts BR-l, 5R-2, and 5Rr-3 to run the main drive motor 4G in the reverse direction. The unchucking operation continues only as long as the operator holds down the push-button M5.

The push-button 225 is for jogging when shifting the speed change gears and the operation of the machine is the same as when unchucking.

With the unchucking operation complete, the operator can then operate the electric motor I97 that actuates the hoist I96 for removing the car wheel from the machine, the push-buttons 2l6 and 2|! providing the means for operating the motor in either direction of rotation for raising or lowering the hoist.

A permanent resistor is used in series with this electric hoist motor I91 to limit the stalled torque of the motor and thus prevents breaking of the hoist chain I98.

In the forepart of the specification it was men tioned that the horizontal facing bar [4 was in' terlocked with the main drive motor with a normally closed contact so that the main drive motor must be operating in order to obtain a feed rate movement of the bar M. This is contact 220 contained in switch I80. The normally open contact that is closed only for obtaining a traverse of the bar [4 is contact 22| in switch IBI.

The aforementioned alternate starting and coasting of the main drive motor as accomplished by the electric circuit just disclosed and described produces the bumping action for closing the clutch jaws as described with reference to the device illustrated in Figure 5, and also, the slow chucking of the car wheel causes a true centering of the car wheel upon the table of the boring machine.

While the apparatus disclosed and described herein constitutes a preferred form of the invention, it is to be understood that the appara tus 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 herein.

I claim:

1. In a vertical boring mill comprising a frame; a spindle journaled in said frame, a work table fastened to the upper end of the spindle, a brake between the lower end of the spindle and the frame, a drive gear concentric'with said spindle having limited free rotation thereon, work holding means on the table connected with said drive gear so that acceleration of the drive gear relative to the table in the forward direction of the table will cause the work holding means to grip a workpiece, while acceleration of the drive gear relative to the table in the opposite direction will cause the work holding means to release the workpiece, a drive motor for driving said spindle, a shaft driven by the motor and a pinion on the shaft meshing with said drive gear, a tool holder reciprocable on said frame axially of said spindle, a positive stop on said frame adapted to be engaged by said tool holder when the tool holder is advanced to a predetermined position relative to said spindle, a timing device operable by the 14 movement of said tool holder into engagement with said stop, and means under the control of said timing device for maintaining said motor energized for a predetermined period of time after said tool holder engages said stop and for then de-energizing said motor while simultaneously energizing said brake, and means operable automatically upon said spindle coming to a complete halt under the influence of said brake for retracting said tool holder.

2. A vertical boring mill having a frame; a Work spindle journaled in said frame for rotation on a vertical axis, a work table on the upper end of the spindle and a brake between the lower end of the spindle and the frame, a drive gear on the spindle coaxial therewith and rotatable on the spindle, chucking means on the work table connected with said drive gear so that acceleration of the drive gear relative to the table in the forward direction of the table will move the chucking means to grip a workpiece, while acceleration of the drive gear relative to the work table in the opposite direction will move the chucking means to release a workpiece, a pinion meshing with said drive gear, a main drive motor drivingly connected with said pinion, a tool holder reciprocable in said frame axially of said spindle, actuating means for said tool holder including control means having a first position to advance the tool holder toward the spindle and a second position to bring about retraction of the tool holder from the spindle, a positive stop on the frame positioned to be engaged by said tool holder in the fully advanced position thereof, a timing device operable by the movement of said tool holder into engagement with said stop, means controlled by said timing device operable thereby for maintaining said motor energized for a predetermined period of time after said tool holder engages said stop while simultaneously maintaining said control means in the said first position thereof, means controlled by said timing device operable a predetermined time after said timing device operable a predetermined time after said tool holder has engaged said stop for simultaneously deenergizing said motor and energizing said brake for arrestin rotation of said spindle, and means associated with the control means operable automatically in response to the halting of said spindle for shifting the said control means to the second position thereof thereby bringing about retraction of said tool holder.

3. An arrangement as set forth in claim 2 in which the actuating means for the tool holder comprises a hydraulic motor and the said control means therefor consists of a reversing valve connected therewith.

OTTO E. SCHURR.

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

UNITED STATES PATENTS Number Name Date 1,649,411 Kaseberg Nov. 15, 1927 2,082,103 Fox et al June 1, 1937 2,084,562 Schafer June 22, 1937 2,174,044 Schmidt Sept. 26, 1939 2,324,727 Shartle July 20, 1943

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