US2220490A - Crank grinding machine - Google Patents

Description

Nov. 5, 1940. c. L.. OTT ETAL CRANK GRINDING MACHINE 5 Sheets-Sheet 1 Filed Dec. 5, 1935 INVENTORS Conra TORNEY Nov. 5, 1940. Q L, OTT ET AL 2,220,490

CRANK GRINDING MACHINE Filed Deo. 5, 1955 5 Sheets-Sheet 2 EEE INV ENTORS A ORNEY TORS W i? pl ORNEY 5 Sheets-Sheet 3 n W l0 mvEN Conrad Raf/l Nov. 5, 1940. c. L. OTT ETAL I CRANK GRINDING MACHINE Novo 5, C. L. CRANK GRINDING' MACHINE 5 sheets-'sheet 4 Filed Deo. 5, 1955 mw. n.. MI- .h N mwwm fww/ B Nov. 5, 1940. c. L. OTT ETAL.

CRANK GRINDING MACHINE Filed Dec. 5, 1935 5 Sheets-Sheet 5 Ra/ Hice. /v/CH fw@ INVENTORS 'conrad L. O

oRNEY Patented Nov. 5, 1940 UNITED STATE-s CRANK GRINDING MACHINE Conrad L. Ott and Ralph E. Price, Waynesboro,

assignors to Landis Tool Company,`

Waynesboro, Pa., a corporation of Pennsylvania Application December 5, 1935, Serial No. 53,086

30 Claims.

Our invention relates to a machine for grinding crank shafts.

The principal object of our invention is to provide a simplified central control mechanism for several of the functions of the machine.

A further object is to control these `functions from a single lever. A further object is to provide safety devices whereby movements which would interfere with one another are prevented from occurring simultaneously.

In the drawings:

Figure 1 is a front elevation of the machine.

Figure 2 is an-end elevation partly in section of the control mechanism and the manual traverse mechanism.

Figure 3 is a sectional front elevation of the control valve showing the arrangement of the various Valves, ports and passages.

Figure 4 is a front elevation of the valve assembly showing an auxiliary operating lever for one of the clamping xture valves.

Figure 5 is asection on the line 5-5 in Figure 3.

Figure 6 is a sectional detail on line 6-6 in Figure 4.

Figure '7 is a front elevation of the control mechanism including the operating mechanism.

Figure 8 is a plan view partly in section of the guide plate for the control lever.

Figure 9 is a plan view of the mechanism for connecting the hand traverse mechanism.

Figure 10 is a plan View showing the structure of Figure 9 in open position.4

Figure 11 is a sketch of the hydraulic and electrical systems on the machine.

'Ihe feature of our invention. lies in a multiple control valve operated by a single lever. Said lever operates four valves, one for the work carriage traverse, one for the spacing bar plunger, one for the hydraulic clamps, and one for the steady rest. The valve for the steady rest has a projecting portion for operating a switch for the headstock motor. The positions of the lever are indicated on a guide plate having a pair of parallel slots connected by a short transverse slot. Movement of the lever in one of theparallel slots actuates the steady rest and the work drive motor and on entering said slot actuates the clamping device. In this slot are initiated functions which should occur during the grinding operation. Movement of the lever into the other slot rst withdraws the plunger from the spacing bar after which movement of the lever to right or left causes movement of the work carriage one way or the other. The functions initiated with the lever in this slot are those which occur between grinding operations. When the grinding Wheel is in working position it is impossible to move the control lever from one slot to the other.

The headstock spindle is lubricated by a supply of fluid under pressure which is controlled by starting and stopping the headstock motor. In the drawings Figure 1,` numeral I0, indicates the bed of a machine on which is mounted a work carriage II. A pair of work heads I2r and I3 are mounted on said carriage and each head carries a clamping fixture I4 in which is supported a work piece I5. A grinding wheel I6 is mounted in a wheel support I'I which is movable transversely toward and from the work either by y mechanical means operated by hand wheel 20 or by hydraulic means operated by knob 2l. A column I8 mounted on said wheel support carries a vertically slidable support I9. A dressing tool is mounted in another `support slidable in a horizontal direction on support I9. Said support I9 may be adjusted vertically by hand wheel 22 thru any suitable mechanism. A plunger 23 slidably mounted in bracket 24 on bed .I0 is adapted to engage notches 25 in spacing bar 26 on carriage I I to locate said carriage in position to permit grinding selected portions of a work piece. A hydraulically operated steady rest 21 is mounted on the bed in line with the grinding wheel. Hand wheel 28 may be used for manually traversing carriage I I.

In Figure 2 is shown the manual traverse mechanism consisting of hand wheel 28, shaft 29, gear 30 on said shaft meshing with gear 3|, and driving thru gears 32, 33, 34, 35, shaft 36 and pinion 3l to rack 38 on carriage I I.

On a portion of shaft 36 extending outside the bed is slidably mounted a spool 39 keyed to said shaft and having clutch teeth 40 adapted to engage clutch portion 4I on the hub of gear 35. Said. gear is mounted to rotate freely on said shaft. A collar 42 is mounted on the outer end of said shaft. A spring 43 mounted on said shaft between said collar and said clutch acts to keep said clutch normally in engaged position. The means for engaging and disengaging said clutch is shown in Figs. '7, 9 and 10 and consists of a yoke 44 in operative engagement with spool 39. Said yoke is pivotally attached to the valve body 46 so that it may have a swinging movement substantially axially of said shaft. A wedge shaped cam 45 is secured to said yoke and held by spring 43 in engagement with a portion of the reversing controls the supply of fluid to the indexing plunger. This valve is urged to the right by a spring and to the left by a lever to be described later.

Relief valve 52 has a reduced portion 53 exposed to pressure. This permits' the use of a lighter spring in said valve.

Valve I4 is urged to the right by spring 5I and controls the supply of fluid to the clamping fixtures I4. 'Ihis valve has a portion extending beyond the valve body with a groove cut therein.

A vertical rod 56 at the side of the valve body is adapted to drop into said groove when the valve is moved to the left. The other end of said rod is attached to one end of a lever 51 pivoted at 58 on the top of the valve body. Said lever is held in position to permit the rod to drop into said groove by a spring 51. A handle 59 may be used to lift said rod from said groove. The right hand end of this valve is hollow to accommodate a ball check valve 42 which seats at the mouth of a smaller bore 63 which is concentric with the larger one. From this smaller bore radial passages 64 extend to an annular groove in the surface of the valve. Radial passages 55 also ljconnect the large bore with a wide annular groove 65. The said grooves are separated by a narrow land I1. Fluid must always pass thru the check valve to reach the clamping fixtures. Valve 54 may be operated independently of lever 83. A lever $5 is pivotally attached at li to a bracket Il secured to the left side of the valve body. A vertical slot thru said bracket serves as a guide for latch rod 56. The other end of said lever carries a pin 91 which is inserted in a slot 98 in a protruding portion of valve 54. V

Fluid under pressure is suppliedvto valves 5l, 54 and il thru a common passage 6|. Two exhaust passages 6I and 69 connect all the valves. Valve 6l controls -the supply of fluid to the steady rest. Two positions of said valve are .determined by two adjacent grooves 10 and 1| into which a spring pressed plunger 12 may drop to locate the valve. The left hand end of said valve is bored out to two diameters to receive -a plunger 13. Said plunger has a piston portion 14 adapted to be inserted in the smaller of the two bores. A radial passage 15 connects said bore with supply passage 6I. However fluid does not reach valve 60 until valve 54 has been shifted to open passage 6| to direct fluid under pressure to the clamp cylinder ||4. A spring 16 holds said plunger in the right hand position. A switch 11 for starting the workdrive motor |22 is attached -to cover plate 18 with a button 19 extending thru to the insideof said cover plate. In normal position as shown this switch connects lines 5 and D thru which current passes to motor |22 thruA tappet switch |44. A bracket 80 secured to the left side of the valve body has pivoted thereon an arm 8| from which extends a pin 82 in the direction of said switch button. Another portion of said arm is in the path of plunger 1I so that when fluid under pressure acts on piston 14, the said plunger is caused to protrude from valve Il and when said valve is'shifted to the left, said plunger will engage arm Il to close switch 11.

The means to operate the several valves comprises a lever 83 pivoted at |84 for movement in transverse directions. 'Ihe movements of said lever are indicated by a guide plate 84. Said guide plate has two parallel slots I5 and I8 with a transverse connecting slot l1. The normal position of the control lever is in slot l1. Movement of the lever 'in slot l5 controls functions which occur during the grinding operation such as work rotation, work clamping and movement 'of the steady rest into operative position. In

one of the projecting portions which form the parallel slots is a plunger Il held in retracted position by a spring Il. Fluid :under pressure may be introduced at the head of said plunger to move the same to block the connecting slot 81. The fluid for actuating said plunger comes from the line thru which fluid passes to move the grinding wheel toward the work. Thus when the wheel is in forward position the lever Il cannot be moved thru slot 81.

Movement of the lever in slots Il controls functions which occur between grinding operations such as operating the index plunger and the traverse mechanism. The movements of the lever may be described as backward and forward, and left and right. At the lower end of said lever is an offset portion having a pair of arms I and 9| extending in substantially opposite directions in a plane parallel to said lever.

ends of saidlarms are adapted when in operative position to fit spools on the ends of valves 41 and When lever 8l is forward, arm 5| is in position to operate valve 41. When said lever is back arm 9| is in position to operate v alve 5l. Said valves are operated by a left and right movement of said lever.

Valves 5l and 54 are actuated by cam surfaces l2 and $3 on a bracket 54. Said bracket is actuated whenlever 83 is moved forward and back. Because said bracket is pivotally attached to lever 83 it is not affected by movements of said Y lever to right and left. Said cam surfaces are located so that a forward movement of lever Il actuates valve 5I while a backward movement actuates valve 54. A backward movement -within the limits of the slot 85 will permit valve 5I to return to normal position which will in turn relieve the pressure on the plunger piston |50.

A supply of lubricant to the crank heads |2 and I3 is controlled automatically by solenoid operated valve |24 actuated by solenoid |23 which in turn is energized when the head stock motor is started. Fluid under pressure from the pump III enters the valve through passage |25 and passes on to the crank heads thru line |26. This machine is also provided with a mechanism for stopping the crank heads in a position where the work can be inserted or removed with the least diiilculty. I'his mechanism consists of a cam |43 mounted on the headstock spindles and disposed in operative relation to a switch |44 which supplies current to the head stock motor thru a line parallel to that in which switch 11 is mounted. Closing either switch will start the headstock motor, but to stop it both must be open. The cam |43 is arranged to open switch |44 when Each of said arms is inclined slightly backward. TheK the clamping fixtures are in a position for unloading.

Operation Fluid under pressure is supplied to the various mechanisms by pump which discharges thru line |0| to supplyl fiud to all parts of valve 46 except the reversing valve 41. A branch line |02 cuts off from 1in-e |0| and the liuid in said line passes thru throttle valves |03 and |04 before reaching valve 41. Additional branch lines supply other mechanisms such as lin'e |05 leading to the wheel dressing device and |06 leading to a backlash cylinder |01. Branch line |08 supplies fluid to the rapid wheel feed mechanism. From the line |09 leading to the head of the wheel feed cylinder ||0 a line |I| conn-ects with the bore in guide plate 84 lin which is mounted the piston which forms .the head of pin 88.

When the operator has placed a piece of work in the machine he shifts lever 83 forwardly thru or from slot 81 into slot 86. This movement of lever 83 places element 90 thereof in position to operate valve 60. This movement also rotates bracket 94 so as to cause cam 93 on said bracket to depress valve 54. Rod 56 drops into the groove in the extension of said valve and prevents return of the valve by spring 55. This causes passage 6| to be connected with port I2 from which uid passes thru line |I3 and lines II3' to the clamping cylinder I|4. Fluid from port ||2 also passes thru line to cylinder I|6 in which is mounted a piston ||1, which actuated by the fluid Iunder pressure, holds a switch arm H8 in oper# ative relation .to a lug ||9 on the wheel base of the machine. Said lug prevents the piston I'I1 from closing the switch. The lever is then moved to the right in slot 86. This movement shifts valve 60 to the left. Fluid has acted on piston 14 within said valve so that pin 13 is in position to engage arm 8| and close switch 11 as soon as the valve is shifted. In Figure 11 valve 60 is shown in normal position. In this position passages 6| and |20 are connected and fluid passes to the head end of steady rest cylinder |30 to hold the work supporting elements in retracted position. As soon as said headstock motor is started solenoid |23 is actuated to shift .valve |24 to permit fluid from the hydraulic system to enter said v alve from passage |25 and pass on thru line |26 to supply lubricators on the crank heads I2 and |3. The operator next pulls knob 2| to shift valve |21 to direct fluid to the head end of cylinder ||0 to move the wheel support y rapidly to grinding position. Movement of the wheel supports acts thru lug I I9 to release switch arm ||8 which completes a pickup circuit to the work drive motor |22. When this circuit is closed the one thru switch 11 may be opened without stopping themotor. Said switch 11 is opened when lever 83 is moved to the extreme left hand position in slot 86 to shift valve 60 to the right. In this position of the valve fluid passes from passage 6| thru line |28 and throttle valve |29 to the rod end of cylinder |30 to move the work engaging elements of the steady rest into engagement with a work piece. The grinding operation continues until the work has been ground to size. Then the operator pushes knob 2| to cause the wheel to move to inoperative position and depress the switch arm I8 to stop the heads. Next he moves lever 83 thru slot 81 to slot 85, pin 88 having been withdrawn when the wheel support was backed oil'. Movement of the lever out of slot 86 first shifts valve 60 to normal position directing uid to the head end of cylinder |30 and thus moving the steady rest away from the work. The operator next presses lever 59 downwardly to withdraw latch rod 56 and permit spring 55 to return valve 54 to normal position where the lines I|3 and ||5 are connected to exhaust line 69 thus permitting the clamping fixtures to be opened and the switch II8 to return to inoperative position. With switch ||8 open the motor |22 will continue to operate until cam |43 opens switch |44. Upon said switch being opened a brake switch |39 becomes operative to stop the motor instantly. Thus the clamps cannot be opened while work rotates because the backward movement of wheel base first stops the work and then releases latch 88 on guide plate so that lever 83 can be moved to position for opening the clamps.

Clamps remain closed and work rotates until wheel moves back because lever cannot move out of clamping position, thus it is impossible to open clamps while heads are rotating. After opening the clamping fixtures the operator rotates the crank shaft to bring another pin on center. Then he shifts lever 83 thru slot 81 into slot 85 and against the side of the slot. This'movement of the said lever causes cam 92 to depress valve 50 so that fluid from line 6I may pass thru line |3| to plunger cylinder |32 and withdraw plunger 23 from spacing bar 26. As soon as said plunger has been withdrawn the operator may move lever 83 either to right or to left dependingon the direction of traverse desired. The previous movement of said lever into slot 85 placed arm 9| in position to shift valve 41. Fluid is supplied to valve 41 from branch line |02 thru throttle valve |03 and |04. Said valve 41 may direct said fluid thru either of lines |33 or |34 to opposite ends of traverse cylinder |35. A line |36 having a check valve |31 therein connects the supply line |3| which feeds the plunger cylinder |32 with line |02 which supplies the traverse motor. After plunger 23 has been withdrawn, pressure is built up in line |3| and fluid passes thru check valve |31 and line |36 to valve 41 and the traverse motor thus increasing the volume of fluid supplied to said motor and increasing the traverse speed, In effect valve 50 becomes a bypass valve around throttle valve |03. Just before the next notch reaches the plunger the operator pushes lever 83 forward in the traverse position. This releases valve 50 sufficiently to permit the exhaust of fluid from the plunger cylinder |32. The extra fluid which increased the traverse speed is thus cut off and the traverse movement is retarded. Check valve |31 prevents fluid in line |02 from passing out thru the exhaust line. The spacing bar moves across the plunger which is held in contact therewith by a spring until said plunger drops into a notch. The operator then returns the lever 83 to neutral position.

We claim:

1. In a machine of the kind described a work support, a tool support, mechanisms for effecting relative transverse and axial movements between said supports, work clamping fixtures on said work support, means to rotate said clamping fixtures, a steady rest, mechanism for moving said steady rest toward and from work supporting position, a lever for controlling said mechanisms, said lever being operable in either of two positions, actuation thereof in one positionbeing effective to operate the clamping fixtures, Work rotating means and steady rest, actuation thereof in the other position being effective to operate said mechanism for effecting relative axial movement between said supports.

2. In a machine of the kind described awork support, workholding and clamping mechanism 5 on said support, mechanism for effecting an axial movement of said support, a plunger and spacing bar for locating said work support in 'predetermined positions, a lever for controlling said mechanisms. said lever having two operative positions in one of which it is effective to initiate functions which are incidental to the machining of a work piece, in the other of which it is effective to initiate functions which occur during the interval between machining operations, movement of said lever into one position being eil'ective to actuate said clamping mechanism to clamp a work piece, movement of said lever into the other position being effective to withdraw said plunger from said spacing bar.

3. In a machine of the kind described, a bed, a work support movably mounted thereon, mechanism for eiecting an axial movement of said support, a plunger land spacing bar for locating said support, in predetermined positions, a lever for controlling operation of said moving mechanism and said plunger, means actuated by movement of said lever in one direction for withdrawing said plunger, means actuated by movement of said lever in another direction for actuating said moving mechanism, the means for controlling withdrawal of said plunger being effective to supply additional power to said moving mechanism, reversal of the first movement of said lever being effective to release said plunger and cut oil! the additional supply of power to said work support moving mechanism.A

4. In a machine ofthe kind described having a bed; a work support, a spacing bar on one of said parts, a plunger on the. other, a group of mechao nisms for performing certain functions during a grinding operation,another group of mechanisms for performing certain functions during the interval between grinding operations including a work support moving mechanism and a plunger 45 actuating mechanism, a lever operablein one position to control said first mentioned mechanisms and in another position to control said second group of mechanisms said levr being effective to control mechanisms in each group as it moves 50 from one position to the other, means actuated by movement of said lever into said second position for withdrawing said plunger from said spacing bar and means operable thereafter by shifting said lever in said second position for 55 moving said work support to the left or right.

5. In a machine of the kind described, a work.

support, work holding and rotating mechanisms mounted thereon, a motor for driving said rotating mechanism, means to actuate said work hold- 60 ing mechanism comprising a lever, a tool support, mechanism for moving said tool support toward and from said work support, means to hold said lever in operating position while said tool support is moving toward or is in advanced posi- 55 tion, means to stop said motor only when said tool support is being withdrawn from working position, the means to stop said motor being effective only when said work holding means is in a predetermined angular position.

6. In a machine of the kind described, a work support, a mechanism on said work support for holding and for rotating a work piece, a tool sup'- port, mechanism for moving said tool support toward and away from said work support, mech- 75 anisms for stopping rotation of said work piece and for opening said work holding mechanism ating said valve. and connection from said solenoid to said motor whereby to open said valve to direct lubricant to said headstock when said motorisstarted.

8. In a machine o! the kind described a bed, a work support, means to eiIect a traversing movement oi' said work support on said bed, means to locate said support in predetermined positions comprising a notched spacing bar and a plunger for entering the notches in said bar, means to withdraw said plunger including a lever to permit traversing movement of said support, means for automatically supplying additional power to speed up said traversing means upon actuation of said lever and means to cut of! said additional supply of power for slowing down said traversing means just before said plunger enters the next notch.

9. In a machine of the kind described a work support, fluid mechanism to eifect a traversing movement of said support, means to supply a predetermined amount of iluid to said traverse mechanism, a reversing valve for directing said iluid to one side or the other of said traverse mechanism, another uid operated mechanism, a second valve for directing fluid to said second mechanism, common means for actuating said valves, and connections for automatically conducting iiuid from said second valve to both mechanisms after said second mechanism has been actuated, whereby to increase the rate of movement of said work support.

10. In a machine of the kind described, a bed, a work support. slidably mounted thereon, a wheel support, iluid means to effect a. relative longitudinal movement of said supports including a iiuid motor, a valve for directing iiuid under pressure to said motor, means to effect said movement intermittently to locate said wheel support and a series of portions of a work piece in operative relation comprising a spacing bar and'a plunger, said plunger having a piston attached thereto, said piston being mounted in a cylinder, means to actuate said plunger including a valve for directing fluid under pressure to said cylinder and a common means' for actuating both of said valves.

11. In a machine of the kind described a base, a work support slidably mounted thereon, work rotating means mounted on said work support including a motor, a wheel support movable toward and from said work support, a circuit for energizing said motor while said wheel support is in advanced position, a second circuit which is normally open and operable regardless of the v position of the wheel support, a lever for opening and closing said circuit, said circuit being closed only while said lever is in closing position.

12. In a machine of the kind described a work support, a wheel support, mechanism for eifecting relative transverse and longitudinal movement of said supports, work rotating and clamping mechanisms on said work support, a lever for controlling operation of said work support and said rotating and clamping mechanisms, said lever being operable in one position for initiating operation of said work rotating and clamping mechanisms and in another position for initiating said longitudinal movement, a latch, and means for positioning same when the wheel support is in an advanced position to prevent shifting said lever from one position to the other.

13. In a machine of the kind described, having a work support, work holding means on said support i'ncluding a work head, a spindle rotatably mounted therein, an electric motor for driving said spindle, a. supply of fluid under pressure for operating various mechanisms on said machine, connections from said supply to said spindle whereby said fluid may be utilized to lubricate'said spindle, a. valve in said connections and means for opening said valve when said motor starts and for closing same when said motor stops.

14. In a machine of the kind described having a work support, work holding means on said support including a work head, a spindle rotatably mounted therein, an electric motor for driving said spindle, a switch for starting said motor, a lever for actuating said switch, a supply of lubricant under pressure for said spindle, means responsive to the pressure of the lubricant for rendering said lever effective to actuate said switch, a valve in said lubricant supply and means operable upon starting said motor for opening said valve. '2

15. In a machine of the kind described a work support, work rotating means mounted thereon, means for driving said work rotating means including a motor and a switch therefor, a source of iluid under pressure, a lever, connections between said lever and said switch including a valve, a plunger movably mounted therein which 40 is normally in an inoperative position and which is held in operative position so long as this iluid under pressure is available.

16. In a machine of the kind described a work support, means for providing a longitudinal 45 movement of said support, means for successively locating said support in a series of working positions, a lever for controlling said locating means and said moving means, means actuated upon movement of said lever in one plane for 50 causing said longitudinal movement and means actuated upon movement of said lever in another plane for operating said locating means and for varying the speed of said longitudinal movement.

1'7. In a machine of the kind described a work support, mechanism for providing a traversing movement of said support, mechanism for effecting said traversing movement either manually or by power, work rotating and clamping mecha- 60 nisms on said support, a single lever for controlling the operation of said mechanisms and automatically operated means for rendering said manual traversing mechanism operable while said lever is in position for operating said work,

lever for controlling said uid mechanisms and said locating means and a valve operable by said lever for bypassing fluid under pressure around said throttle valve.

19. In a machine of the kind described a work support, work rotating means including an electric motor, a switch for said motor, a cam rotatable with said work for intermittently opening said switch, a second switch having two poles one of which is between said first mentioned switch and a source of electric current, the other of which supplies current to said motor direct, and a third switch operated independently of said second switch connected to said motor in parallel with said other switches.

20. In a machine of the kind described a work support, work rotating means including an electric motor, a switch for said motor, a cam rotatable with said work for intermittently operating said switch, a second switch between said rst switch and a source of current, said second switch having two sets of contacts, one of which is normally open but effective when closed to start said motor, the other of which is normally closed but ineffective to start said motor, said normally closed contact being in series with said cam operated switch, a third switch operable independently of said second switch for supplying current to said motor, said third switch being connected to said motor in parallel with said cam operated switch.

2l. In a machine of the kind described a work support, work rotating means including an electric motor, a plurality of circuits for supplying current to said motor including a circuit for starting said motor, a circuit operated independently of said starting circuit for supplying current to said motor after the starting circuit is opened and a third circuit in parallel with said second circuit, which is opened and closed intermittently in synchronism with the rotation of the work..

22. In a machine of the kind described a work support, work rotating means including an electric motor, mechanism movable relative to said work support, a plurality of circuits for supplying current to said motor one of which is normally closed at one point and at another point is opened and closed in time with the rotation of the work,

another of which is connected in parallel with said rst circuit and which is opened and closed by movement of said mechanism, a third circuit which is eiTective only to start said motor and means for closing said rst and third circuits alternately.

23. In a machine of the kind described, a work support, work rotating means including an electric motor, mechanism movable relative to said work support, a plurality of circuits for supplying current to said motor, one of which includes at one point a normally closed switch, and at another point a switch opened and closed in timed relation with the rotation of the work, a second circuit which is connected in parallel with said first circuit, and which comprises a switch which is opened and closed by movement of said mechanism, a third circuit which includes a switch which is effective only to start said motor, and means whereby said starting switch and said normally closed switch are opened and closed alternately.

24. In a machine of the kind described, a work support, a tool support and means for causing a relativetransverse movement between said supports, work rotating means including an electric motor, a plurality of circuits for supplynt current to said motor including a circuit for starting said motor,a circuit operatedindependently o! said starting circuit and in response to said transverse movement for supplying current tsaid motor after the starting circuit is opened ing relative movement of said supports, a manually operated mechanism for effecting said movement including a handwheel, a gear assembly, a clutch connecting said parts, means ingagins said clutch and initiating movement oi' s said power means.

26. In a machine tool, awork support, mechanism for providing a traversing movement of said support either manually or by power, a

' reversing lever which is shiftable in opposite directions'to determine the direction of movement of said carriage and ior initiating said movement, and connections between said reversing lever and said .manual traverse mechanism operable upon shifting of said lever in either direction for rendering said manual traverse mechanism inoperative.

27. In a machine tool, a work suppoi't. work clamping means rotatably mounted on said support, a single lever for controlling operation of a plurality of mechanisms on said machine, means actuated by said lever for operating said clamps to grip a work piece, and means to prevent opening of said clamps when said lever is moved to another position including a latch for holding said .clamp operating means in position to eii'ect clamping of the work.

28. In a machine of the'` kind described, a work support, mechanism for eiecting a traversing movement of said support, work clamping mechanism mounted on said support. mechanism for rotating said clamping mechanism, means for actuating said mechanisms comprising a main control lever and an auxiliary lever for actuating said clamping mechanism when said main contr`ol lever is being used to control another mechanism.

29. In a machine of the kind described, a work support, mechanism for eiiecting a traversing movement ofsaid support including a supply of iluid under pressure, a throttle valve in said supply, a second-iluid operated mechanism for locating the work table, an unrestricted passage connecting said supply and said locating mechanism, a start and stopfvalve for said traversing mechanism, and a connection controlled by said start .and stop valve for supplying additional fluid under pressure to said traversing mechanism at the same time that said second mechanism is actuated.

30. In a machine of the kind described, a work carriage, means for eiIecting intermittent longitudinal movement of said carriage including a hydraulic motor, a spacing bar on said carriage having a series of spaced portions, a plunger for cooperating withsaid spaced portions for controlling said intermittent carriage movement. a lever for initiating said carriage movement and for determining the direction of said movement, said lever being operable also to direct iluid under pressure for withdrawing said plunger, and means for utilizing said plunger operating nuid to increase the speed of said carriage movement.

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