USRE21434E - Machine tool transmission and control - Google Patents

Description

April 23, 1940. w. M. For. ET AL MACHINE TOOL TRANSMISSION AND QONTROL Original Filed Jan. 27, 1953 5 Sheets. neet 1 1 VIEW) 5 AT ToRNEY April 23, 1940. w. M. POHL ET AL 21,434

MACHINE TOOL TRANSMISSION AND' CONTROL Original Filed Jan. 27, 1933 5 Sheets-Sheet 3 April 23, 1940. w. M. POHL ET AL MACHINE TOOL TRANSMISSION AND CONTROL Original Filed Jan. 2'7, 1933 5 Sheets$heet 4 "7 AT' R Y April 23, 1940. w. M. POHL ET AL 21,434

MACHINE TOOL TRANSMISSION AND CONTROL Original Filed Jan. 2'7, 1933 5 Sheets-Sheet 5 mv T01? 2pm ATTORNEY Reiuued Apr. 23, 1940 PATENT OFFICE MACHINE TOOL TRANSMISSION AND CONTROL Walter M. m1, Washington, D. 0., and Joseph B. Armita ge, Wauwatosa, Wia, assignors to Kearney a Trecker' Corporation, West Allis,

Wis., a corporation Original No. 2,110,173, dated March 8, 1938, Serial No. 653,872, January 27, 1933.

Renewed July 30, 1936. Application for reissue May 27, 1939,

Serial No. 276,086

49 Claims.

This invention relates generally to transmission and control mechanism for driving machine tool spindles, and more particularly to the tool spindle drive of a milling machine.

A primary object of the invention is to provide improvedrate changing means covering a wide range of rates between the highest and lowest available speeds. and in which the different speeds form a series having relatively small increments of rate change, and to provide control mechanism for the transmission having a single lever or shifter for effecting all of the rate changes and operable for'effecting the changes in their numerical sequence or order.

Another object is to provide a rate changer, particularly for spindle drives where there is involved the use of relatively heavy shiftable gearing, with control mechanism such that the gearing cannot be shifted in a manner which might cause breakage or'damage to the gears.

Another object is to provide improved mechanism for facilitating the shifting of speed changing gearing.

Another object is to provide in a machine tool safety features preventing damage or breaking of the rate change elements or gears, which function automatically and without the need for any attention or operation on the part of the operator other than that normally required for effecting a desired change of rate.

Another object relates to providing a rate changer, such as has been previously referred to, with a safety device or interlock insuring that the rate changer and the mechanism driven therethrough is disconnected from the normal drive train at the time that a desired rate change is effected.

Another object is to provide mechanism for a rate changer of the' type involving shiftable gearing or similar rate change elements which will insure that the rate changer is disconnected from its normal driving mechanism during the interval in which adesired change of rate is to be effected, and connected instead to a driving mechanism which will rotate the rate change elements relatively slowly, in order to avoid the disadvantages arising from the intermeshing of elements at high speed, while still insuring that the elements are in motion in order that they may be more easily shifted and that the shifting thereof may not be blocked.

Other objects relate to the use of improved hydraulically operated mechanism, both to shift out of engagement the main clutch of a spindle or similar driving train during the interval when a rate change is to be effected, and also to similarly shift into engagement an auxiliary driving connection for rotating the spindle and the rate changer thereof slowly during said interval.

Further objects are generally to improve; and simplify the construction and operation of transmission mechanism, particularly for machine tool spindles and more particularly for the spindles of milling machines, and still further objects will be apparent from the specification and claims.

The invention consists in the construction, arrangement, and combination of parts as herein illustrated, described, and claimed, and in such modifications thereof as are equivalent to the structure claimed.

Fig. 1 is a view in rear elevation of a knee and column type of milling machine which incorporates the invention.

Fig. 2 is a view in front elevation of the column of the machine, the knee, table, and saddle thereof not being shown in this view.

Fig. 2a is a partial view of the column in left side elevation showing the speed indicating device.

Fig. 3 is a partial view in section taken along line 33 of Fig. 5, enlarged.

Fig. 4 is a partial view in section taken along line 4-4 of Fig. 2, enlarged.

Fig. 5 is a view in section taken along line 55 of Fig. 1, the knee, saddle, and table of the machine not being shown.

Fig. 6 is a diagrammatic view showing a development of the spindle driving train.

Fig. '7 is a detail view in section taken along line of Fig. 4.

Fig. 8 is a view in cross section taken along line 88 of Fig. 9.

Fig. 9 is a view in longitudinal section taken along lines 9-9 of Figs. '7 and 8.

Fig. 10 is an enlarged semi-diagrammatic view of certain of the rate change mechanism shown in Fig. 6 and some of the associated elements.

Fig. 11 is an enlarged view in section showing some of the details of a gear shifting device incorporated in the machine.

Fig. 12 is an enlarged view in section with parts broken away taken along line I 2l 2 of Fig. 1.

Fig. 13 is a partial view in section taken along line'l3l3 of Fig. 12.

The milling machine herein illustrated includes a hollow column I, within which is a lower chamber 2 housing a prime mover or driving motor 3. A pulley 4 mounted on the shaft 5 of a substantially constant speed motor 3 drives a u pulley May the means of multiple belts 1. Pulley lis withashaftl. Ashaftiiscoaxialwith' shaftlandmaybeconnectedordisconnected therefrom by the means of a main clutch; generally denoted by the numeral ii, there being a clutch member fixed on shaft 3 and a second clutch member |2 slidably keyed on shaft 3 which may be shifted into or out of engagement with the clutch member II for this purpose. A brake member I3 fixed with clutch member l2 operates to engage complementary brake or friction surfaces between the brake member l3 and a member |4 fixed with the column when the clutch disengaging movement of member I! is continued, as more fully shown in Fig. 6.

The clutch l2 and brake l3 may be manually operated by the means of a controller or lever l5, Figs. 1, 2, 5, fixed with a shaft is which operates a shaft 1, Figs. 1, 2, through gear segments II, II. A gear segment 20, Figs. 2, 5, and 7, fixed at the lower end of shaft l1, engages rack teeth of a rod 2| slidably supported and carrying a fork 22 engaging a suitable annular groove in the shiftable clutch member l2.

As best shown in Fig. 6, shaft 9 drives a shaft 23 through a first or primary rate changer generally designated by the numeral 24 and constituting a part of a variable speed transmission mechanism for driving the milling machine spindle. The shaft 23 drives a shaft 25 in either direction through a reverser generally designated by the numeral 25. Shaft 25 drives spindle 21 through a second or supplementary rate changer generally designated by the numeral 28, the rate changers being serially arranged.

The first or primary rate changer 24 is constructed as follows: Gears 29, 30, 3| are slidably keyed with the shaft 9 and fixed together for unitary axial movement for engagement one at a time respectively with gears 32, 33, 34 which are fixed together and rotatably supported on a shaft 24a. Another gear 35 is also fixed with shaft 24a and gears 33, 31, 33, slidably keyed on a sleeve 39 in driving relation to the shaft 23, are adapted for engagement one at a time with the gears 34, 33, and 35 respectively complementary thereto. The arrangement is such that the various positions of the shiftable gears provide nine changes of rate between the driving shaft 9 and the shaft 23, and since the diflerence in gear diameters is relatively small, the rate changes effected form a series having nine relatively small increments.

The reverser 26 is constructed and operated as follows: slidably keyed on shaft 23 is a unitary pair of gears 40, 4|. In the one position of axial adjustment of the gear pair, the gear 40 engages a gear 42 fixed on shaft 25. In another position of axial adjustment the gear 4| engages an idler 43 which drives a gear 44 fixed on shaft 25. The gear pair 40, 4| may be shifted to the one or the other position by the means of a hand lever 45, Figs. 5 and 12, fixed on a shaft 46 having teeth engaging a rack bar 41 upon which is fixed a fork member 48 engaging a suitable annular groove 49 in the hub of the gear pair 40, 4|.

The second or supplementary rate changer 28, Figs. 5, 6, 10, 12, is constructed as follows: A gear 50 is slidably keyed to a shaft 5| and is shiftable into and out of engagement with the gear 42 whereby to connect or to disconnect a high speed train consisting of gears 42, 50, shaft 5|, a helical or worm gear 52 fixed on shaft 5|, and a complementary helical pinion or worm 53 fixed on the spindle 21. Two other power trains are also driven from shaft 25 through bevel gears 54, 55

and a's haft a. The two'trains .iustreferred to consist respectively of the gear 51 slidablyspiined with-shaft II and engageable with a gear 54 fixed with spindle 21 to form a low speed train; and

a gear 53 slidably splined on shaft 53 and engageable with a gear Ill fixed with spindle 21 to form an intermediate speed train. The gears 51, 53 are fixed together for unitary movement and arranged to be engageable one ata time. The combined 'efi'ect of the mechanism described is to give three separate power trains of different rate effect from the shaft 25 to the spindle which, in combination with the first rate changer, provides 21 changes of .spindle speed. The. differences in diameter of the gears fixed on the spindle 21 are such that the increments of rate changes efiected by the second rate changer 28 are each larger than the total range of rate changes efiected by the first rate changer.

The speed selector mechanism for the shifting of the rate changer elements, although it differs somewhat in structure, is similar in its action to that disclosed in Patent No. 1,817,036, issued August 4, 1931. The structure of the mechanism herein disclosed is as follows: a

The first and second rate changers are each operated or adjusted by means of a controller or lever 6|, Figs. 2 and 10, which carries a spring pressed plunger 52 normally engaging a bore or socket 63 whereby to lock the rate changers in the various positions of adjustment. Plunger 62 may be withdrawn to unlock the rate changers in initiating an adjustment thereof, by a handle 6|a. The lever 6| is fixed on a sleeve or hollow shaft 64 upon which are fixed gears 55, 66, Fig. 10. Gear 55 drives a shifter train consisting of the gear 65, a gear 51 engaging therewith, a gear 68 fixed on shaft 69, Figs. 10, 12, 13, bevel gears 10, 1|, shaft 12, gear 13 fixed on shaft 12, a gear 14 meshing with gear 13, and a pair of intermittent gears 15, 16, the gear 15 being fixed with gear 14 and driving the gear 15 in a manner such that after each one-third revolution of the gears together, the gear 15 remains stationary while gear 15 completes an additional movement of twothirds revolution. Thus the gear 14 completes three revolutions to one revolution of gear 16. Fixed with gear 15 is a pin or shoe 11, Figs. 10, ll, 12, forming an eccentric engaging a suitableslot in a shiftable member 18 which shifts a fork member 19, Figs. 11, 12, through the intermediate agency of a spring 80, the fork 19 engaging the sides of gears 31, 38 for movement thereof, the action being such that each half revolution of gear 14 shifts the gears 36, 31, 38 from the one to the other end of their movement through the intermediate position, and the next suceeding half revolution shifts them back again. Similarly the gear 16 carries a pin or shoe 8|, Fig. 10, engaging a slot in a member 82, Fig. 12, which shifts a fork member 83 engaging the sides of the gear 30, there being a spring element, not shown, in the train to fork 83, similar to spring 30 in the train to fork member 19.

The intermittent gears 15, 15 and the eccentric operative therefrom are of such form and relationship that the gears 36, 31, 38 are shifted through each of their positions while the gears 29, 30, 3| are held in each of the positions thereof whereby a complete shift of the gears 23, 30, 3| to each of the positions thereof is productive of the entire series of nine speeds of the first rate changer.

The lever 5|, in addition to the shifter trains for the primary rate changer just described, also a gear 05 which meshes with a gear 06, fixed with y a gear 91 engaging a gear 99 fixed on a shaft 09. Shaft 09 has fixed thereon a cam 90 having a groove 9| engaging a pin or follower 92 fixed in a fork or shoe member 93 which engages an annular groove 94 in the hub of the gear 50. By the described shifter train a shifting movement of lever I moves gear into and out of engagement with the gear 42, thus engaging or disengaging the high speed train of the second rate changer. Fixed with gear 90 on shaft 99 is an intermittent gear engaging an intermittent gear 90 fixed on a shaft 91 upon which is also fixed a member 99 carrying a pin or shoe 99 forming an eccentric engaging a suitable slot I00 in'a member IOI fixed on a shiftable rod I02, Figs. 10, 12, upon which is also, fixed a fork member I03 engaging the sides of the gear 99. The intermittent gears 95, 96, the eccentric member 90, and cam 90 are of such form and relationship that gears 50, 51, 99 are shifted into engagement one at a time whereby the low, intermediate and high speed trains of the second rate changer are operative one at a time and never simultaneously as to any two thereof.

The shifter trains operative from gears 65 and 99, respectively for the first and second rate changers are of such form and relationship that the first rate changer is shifted through its entire series of nine speeds while the second rate changer is retained in each of the three positions respectively productive of its high, intermediate and low rates, whereby a complete shift of the second rate changer is productive of each of the twenty-seven speeds of which the spindle drive train is capable. Also the arrangement of the shifter trains is such that in each direction of rotation of lever BI the various speeds are arrived at in numerical order, and such that one revolution of the lever is productive of a change, from one speed to the next speed of the series, either higher or lower according to the direction of lever movement.

A speed indicating device is associated with the shifting mechanism as follows: A chart or dial I04, Figs. 2a, I0, is rotatably-supported for movement adjacent to an indicator or pointer Illa, the chart being geared for movement in accordance with the shifting movement of lever 6|, there being a ring gear I05 fixed with the dial and engaging a gear I06 fixed for rotation with the gear 01 of one of the shifter trains previously described. The dial I04 has a series of indicia corresponding to the value and order of the rates obtained by the operation of lever GI and the relation is such that one revolution of lever 6i, which, as explained previously, effects a change from one speed to the next, likewise moves the indicating device to a corresponding one of the various indicia thereon, whereby in any position of the rate changers the indicating device correctly shows the speed available at the time.

The mechanism previously described is the normal spindle operating train. To facilitate gear shifting, there is also provided an auxiliary or branch train for relatively slow rotation of the gearing of the rate change devices as follows: Fixed with the clutch member II is a gear I01 engaging a gear. I08, Fig. 3, which is supported on a shaft I09 but normally free therefrom. A clutch member IIO fixed on shaft I09 may be shifted to engage complementary clutch surfaces on the member H0 and gear I00 by shifting the shaft I09 endwise, which is accomplished by mechanism to be later described, andwhen so shifted, the shaft will be driven from gear I00. The friction surfaces are such that unless the shaft is forcibly shifted, they will disengage,

,whereby theshaft is normally free of'the gear.

Fixed on shaft I09 is a gear III engaging with a gear H2, Fig. 3, the hub of which provides an outer member for a one-way or overrunning clutch device generally denoted by the numeral 3, Fig. 3. The overrunning device II3 includes an inner or cam member I" fixed on a shaft H5, rollers or similar elements IIG interposed between suitable cam surfaces of the member I I4 and the bore of the hub of gear H2 and a cage member ill for the rollers IIG normally pressed by a spring IIO to rotate relative to the member Ill in a direction to cause the rollers iii to ride upon suitable cam surfaces of the mem- .ber II! in a direction to cause the rollers lIIi fixed on the shaft 9. The arrangement is such that the shaft II5 may drive shaft 9 or be driven therefrom, but if driven from the shaft 9 the overrunning clutch device II3 will disengage whereby the gear II2 will not be driven from the shaft. By the mechanism described the gear I00 may drive shaft 9 in the event that the clutch member I I0 is engaged and in the further event that the shaft 9 is not rotating at a speed sufficiently high to move the shaft II5 faster than it would be rotated by the gear II2. The train just described is relatively a very slow speed train and since the normal driving mechanism for shaft 9 is of relatively high speed, the shaft 9 by reason of the overrunning device can never drive the gear II2, although the gear II2 may drive theshaft 9. At the time the clutch member H0 is shifted into engagement, the main clutch I0 will be disengaged by mechanism later disclosed, but even if this did not occur, no damage would result'for the reason that the overrunning device would prevent gear II2 from being simultaneously driven through two trains of different speed.

Mechanism to simultaneously shift the main clutch I2 and brake member I3 to a central or neutral position and to shift the clutch member IIO of the slow speed train, just described, to its engaged position for rotation of the spindle train at relatively very slow speed, operates automatically whenever plunger 62. Fig. 10, is withdrawn to permit a change in the spindle rate, the mechanism being as follows: A lever I2I, Fig. 10 is movable within a suitable bore I22 in the arm of lever BI, being pivoted on a spherical portion I23 fitted within the bore and has a rounded outer end portion I24 engaging an annular groove in the plunger 62 and a rounded inner end portion I25 engaging a suitable annular groove in a rod or plunger I26 fitted within the bore of the hollow sleeve or shaft 64. The rod I25 extends into a valve generally indicated by numeral I21 supplied with fluid from any suitable source, such as a pipe I28. An annular groove I29 in the rod I26 normally provides free communication between a port I30 which communicates with the supply pipe I28 and an outlet port I3I which communicates with an outlet pipe I32. But in the event that the plunger 62 is withdrawn to initiate a shifting movement for eflecting a change in spindle rate. the lever I2I moves the rod I23 to close communication from port I33 to the port III and to open communication with a port I33 communicating with a pipe I34 which is used to supply fluid to the clutch shifting mechanism previously mentioned.

Fluid for shifting the main clutch I3 is supplied irom the pipe or channel I34 to'a device generally denoted by the numeral I33, Figs. 4,

7, 8, 9, including a cylinder I33, a piston I31, and

a piston rod I33, having rack teeth engaging the gear segment 23 at the side opposite to that engaged by the shifter rod 2I which carries the fork 22 engaging the shlftable clutch member I2. The piston I31 has a central position in which a port I33, Fig. 3, supplied from the pipe I34 is in communication with each of two recesses I43, I4I respectively engaging with the channels I42, I43 leading to the opposite ends of the cylinder. If the piston is displaced from the central position, the one or the other of the recesses passes out of communication with the supply port I33, but since the port is supplied with pressure fluid from the valve I21 only when the plunger 32 is shifted for a change of speed, there is no tendency to move the piston I31 back to its central position unless the plunger 32 has been so moved. The piston I31 may, therefore, normally freely take up any of the positions brought about by the movement of the segment 23 to engage clutch I2 or brake l3 from hand lever I5. During hand movement the piston displaces fluid in the cylinder (which might otherwise retard or prevent the movement of the piston) since in either direction of piston movement, the fluid may pass out of the cylinder through the one or the other of channels I42, or I43, and the one or the other of recesses I43 or HI and into the port I33 and channel I34 from which it may escape through the bore of the valve I21 and out through a vent hole I44, Fig. 10, the end of the rod I23 being reduced to permit communication from the channel I34 through the port I33 and the bore of the valve when the rod I26 is in the position normally occupied at the time that the plunger 32 is seated, and excepting only when the plunger 32 has been withdrawn to effect a rate change. Thus at any time when the clutch I2 or brake I3 are intended to be operated by hand, that is to say, at any time except when a rate'change is to be effected by the lever 3|, the piston I31 may be freely moved from thesegment 23. To further prevent any drag on the manual movement of the piston I31 in either direction of its movement from the segment 23, vents I45 and I43 are provided. These vents are so positioned with respect to the length of the piston that neither is open when the piston is in central position thereby preventing the escape of fluid pressure from the port I33, but if the piston is being displaced from the central position by the movement of the segment 23 from hand lever I5, the one or the other vent immediately opens to avoid a vacuum being set up and to admit fluid from a reservoir I41 with which each of the vents communicates.

For controlling the auxiliary or, slow speed train, a device generally indicated by the numeral I43, Figs. 3 and 4, is used to shift the clutch II3 into and out of engagement in accordance with the fluid pressure in the channel I34, that is to say, to shift the clutch II3 into engagement when the movement of plunger 32 for the eiifecting of a speed change has caused fluid to be supplied to the channel I34 from the valve I21, and to disengage clutch I I3 when the rate change is completed. The device I43 is supplied with fluid through a pipe or channel I43, but only when the piston I31 of the device I33 is in its central position, that is to say, after the clutch I2 and brake I3 have both been disengaged. Device I43 consists of a cylinder I53 in which a piston II is fitted and projects therefrom in a manner for a shoe or element I52, Fig. 3, to be pressed against the end of the shaft I33, whereby to move the shaft axially in a direction to cause engagement of the friction elements of the clutch II3. Normally the piston I5I is pressed in the opposite direction by a spring I53, but when fluid under pressure is admitted from pipe I34 through the channel I43, the fluid pressure in cylinder I53 overcomes the spring and causes engagement of the clutch. As previously stated,

fluid pressure is available through the channel I 43 only when the piston I31 of the device I35 is in its central position, thus providing an interlock preventing engagement of both clutches simultaneously, this effect being obtained by structure as follows: A recess I54 in the piston I31 is of such form and position that it provides communication between the supply port I33 and a port I55 communicating with channel I43 only when the piston I31 is centrally positioned. This provides the desired restriction as to the supply of fluid to the cylinder I53. The fluid supply is further restricted by the fact that irrespective of the position of the piston I 31, the channel I34, from which channel I43 must be supplied, contains no fluid under pressure unless the plunger 32 of the rate change device has been moved to effect a rate change. As has been previously explained, the friction surfaces of the clutch II3 are of such form that immediately after pressure has been removed, they will be disengaged and by the mechanism described the clutch H3 is invariably disengaged except when a rate change is to be effected and then only after the clutch -I2 and brake I3 have been disengaged.

Fluid may be supplied to the valve I21 through pipe I23 from any suitable source, as previously stated, but in the present instance there is utilized for the source a pump I56, Figs. 5, 6, which is also utilized for the lubrication of the spindle train. The spindle train is housed within the hollow column I and there is provided a header I51, Figs. 2 and 5, which sprays fluid over the rotating gears and into suitable channels leading to the various bearings for the lubrication thereof, the fluid being supplied from a reservoir indicated at I53, Fig. 5, through a supply channel I53 to the inlet port of pump I53 from which it passes through a. channel or pipe I63 to a filtering device IIiI and thence through the channel I28 to the valve I21. In the normal position of the plunger I26, that is to say, except during a shift of the spindle rate changer, the port I33, Fig. 10, of the valve I21 communicates through the recess or groove I23 in the rod I26 to a port or opening I3I from which the fluid is passed to a lubricating supply pipe I32 which terminates in the header I51, previously mentioned. When the rod I23 has been shifted to the position in which the fluid from the supply pipe I23 is directed to the port I33 communicating with the pipe or channel I34, the port I3I is closed by the body of the rod I26 and until the devices I35 and I43, which are supplied with fluid from the channel I34, as previously described, have performed their function,

the flow of fluid to the lubricating system is substantially interrupted. However, immediately after the devices I35 and I 43 have operated, fluid is no longer withdrawn to the channel I34 but is then passed instead through a channel I58 and a pressure regulating or limiting device generally denoted by numeral I59 and then'again supplies the lubricating channel I32 with fluid. The pressure regulating device I59 consists of a spring pressed ball I60 adapted to close channel I53, except when the pressure therein rises above the pressure of a spring I6! and also adapted to prevent fluid from reaching the channel I34 from the port III or pipe I32. Thus even during the interval when a rate change is being effected and except for the fluid necessary to supply the devices I35 and I48, the lubricating channel I32 receives the full supply of fluid from the pump I56, yet such fluid is always available at the proper time for the supply of the channel I34.

Having now revealed the invention, what is claimed is:

1. In a machine tool, the combination of a transmission including an adjustable rate changer, a substantially constant speed power source, a plurality of power trains respectively for connecting said source to drive said rate changer at a normal operating rate and a relatively slow rate; and control mechanism for said transmission including means for adjusting said rate changer and having an operative and an inoperative position, means shiftable for effecting said slow rate of the one or the other of said normal and relatively slow rates, and means connected to be moved upon movement of said adjusting means to operative position and operative for shifting said shiftablemeans to effect said relatively slow rate during rate changer adjustment.

2. In a milling machine,'the combination of a rotatable tool spindle, a transmission therefor including a rate changer comprising a plurality of elements adjustable into a variety of element combinations each productive of different spindle speeds, a plurality of trains respectively for driving said rate changer at a normal operating rate and a relatively slow rate; and control mechanism for said transmission including means for adjusting said rate changer and having an operative and an inoperative position, means shiftable for connecting said relatively slow driving train, and means connected to be moved upon movement of said adjusting means to operative position and operative for effecting said connection of the relatively slow driving train.

3. In a, machine tool, the combination of a transmission including an adjustable rate changer, means for driving said rate changer including a plurality of power trains respectively operative at a normal rate and a relatively slow rate; and control mechanism for said transmission includ ing a power operable device for connecting said relatively slow rate driving train, a power connection for said device, a member shiftable to a plurality of positions during adjustment of said rate changer, and means connected to be moved upon movement of said adjusting means to one of said positions and operative to control said power operable device.

4. In a machine tool, the combination of a transmission including an adjustable rate changer, a plurality of trains respectively for driving said rate changer at a normal rate and a relatively slow rate; and control means for said transmission including a fluid operable shifter for connecting said relatively slow rate driving train, a source of fluid supply connectible for operation of said shifter, a valve controlling operation of said shifter from said fluid supply source, a member shiftable during adjustment of said rate changer, and a motion transmitting connection from said member to shift said valve during rate changer adjustment to a position effecting said slow rate.

5. In a machine tool, the combination of a transmission including an adjustable rate changer, a plurality of trans respectively for driving said rate changer ata normal speed and a relatively slow speed; and control mechanism for said transmission including adjusting means for said rate changer, locking means adapted to selectively retain said rate changer in different positions of adjustment thereof and including a member shiftable for unlocking said means, a shifter device for connecting the relatively slow rate driving train, and.a motion transmitting connection from said member to said shifter device for operation thereof to effect said slow rate during rate changer adjustment.

6. In a machine tool, the combination of a transmission including an adjustable rate changer, a plurality of trains respectively for driving said rate changer at a normal speed and a relatively slow speed; and control mechanism for said transmission including adjusting means for said rate changer, locking means adapted to selectivelyretain said rate changer in different positions of adjustment thereof and including a member shiftable for unlocking said means, a fluid operable shifter device for connecting said slow rate driving train, a source of fluid supply connectible with said device, valve means controlling the supply of fluid from said source to said device, and a motion transmitting connection from said member to shift said valve means during rate changer adjustment to a position effecting said slow rate.

7. In a machine tool, the combination of a transmission including an adjustable rate changer, a plurality of trains respectively for driving said rate changer at a normal speed and a relatively slow speed; and control mechanism for said transmission including adjusting means for said rate changer, locking means adapted to selectively retain said rate changer in different positions of adjustment thereof and including a member shiftable for unlocking said means, a lubricating system for said transmission including a pump and areservoir, a fluid operable shifter device for connecting said slow driving train, valve means adapted to connect said pump for operation of said shifter device, and a motion transmitting connection from said member to shift said valve means to effect said slow rate during rate changer adjustment.

8. In a machine tool, the combination of a transmission including an adjustable rate changer, a plurality of alternative drives for said rate changer including a normally speeded drive providing motion interrupting means and a relatively slow speed drive providing a drive connecting means and an overrunning device, and means for substantially simultaneously operating said motion interrupting means and said drive connecting means.

9. In a machine tool, the combination of a transmission including an adjustable rate changer, drive -means therefor including a driving clutch and a brake, means shiftable to selectively connect] said rate changer with said clutch or with said brake or to disconnect said rate changer from both said clutch and said brake, means for shifting said shii'table means, adjusting means for said rate changer, and means operative in accordance with said adjusting means for the operation of said shiftable means.

10. In a machine tool having a tool support and a work support. the combination oi a transmission for movement of one of said supports including a rate changer adjustable for a series of predetermined ratm including a high rate, a low rate and a variety of intermediate rates, a substantially constant speed power train operative to drive said rate changer at a normal rate productive of said predetermined rates, a device operable for alternatively establishing or interrupting said drive, a relatively slow speed train connectible to drive said rate changer, means for connecting said slow speed train, and control mechanism for said transmission including a chart having indices respectively corresponding to different of said rates, indicating means movable relative to said chart, means for adjusting said rate changer to different positions respectively selective of one or'another of said rates,

'a connection operative for relative adjustment of said chart and indicating means in accordance with movement of said rate changer adjusting means, means for operation of said device, and means operatively connecting said device operating means, said rate changer adjusting means and said means for connecting said slow train to prevent adjustment of the rate changer while said device is operative to establish said drive and to prevent adjustment of said rate changer except during connection of said slow train.

11. In amachine tool, the combination of a transmission including an adjustable rate changer, a power source, a brake, a normal speed train including an element shiftable to alternatively connect said power source or said brake to said rate changer and having an intermediate position disconnecting both said power source and said brake, a relatively slow train connectible to drive said rate changer, adjusting means for said rate changer, a device for substantially simultaneously shitting said element to said intermediate position and connecting said slow train to drive said rate changer, and means operative from said rate changer adjusting means to operate said device for connecting said slow train during rate changer adjustment 12. In a machine tool having a power transmission mechanism including an adjustable rate changer, the combination with a clutch engageable to eflect driving of said and a brake engageabie to stop'said mechanism, of means arranged to adjust said rate changer, and means associated with said adjusting means and operative thereby in manner to automatically disengage both said clutch and said brake upon movement of said adjusting means in initiating adjustment of said rate changer.

13. In a machine tool having a traon mechanism including an adjustable rate changer, driving means for said rate changer including a disconnecting clutch, a brake associated with said rate changer for stoppin it, adjusting means for said rate changer, and power actuated means responsive to movement of said rate changer adjusting means and operative to disconnect said clutch and to disengage said brake when said adjusting means is moved in adjusting said rate changer, thereby facilitating said djustment.

ILInamachinetoolhavingaspecdchanging power mechanism including shiftable gearing, driving means for said transmission mechanism including a power source and a selectively engageable clutch arranged to operatively connect said power source to said mechanism, a lubricating system for said transmission mechanism, a lubricating pump connected to furnish oil under pressure to said lubricating system, hydraulically actuated means arranged to be operated by oil under pressure from said lubricating p nnp andeflective to disengage said clutch, means arranged to shift said gearing. a hydraulic control valve operative in response to a shifting movement of said gear shitting meansto close the connection from said pump to said lubricating system and to admit oil under pressure from said pump into said hydraulically actuated clutch disengaging means for eifecting disengagement of said clutch prior to shifting of said gearing, and pressure limiting means arranged to relieve the pressure of said actuating oil in said hydraulically actuated means when it exceeds a predetermined maximum and to permit excess oil therefrom to flow into said lubricating system.

15. In a machine tool having a speed changing power transmission mechanism including shiftable gearing, driving means for said transmission mechanism including a power source and a selectively engageable clutch arranged to operatively connect said power source to said mechanism, means actuated by said power source and operative to disengage said clutch, an auxiliary drive apparatus arranged to alternatively drive said mechanism from said power source at a low rate of speed to facilitate shifting of said gearing when said clutch is disengaged, means operative to shift said gearing, and control means operative by said gear shifting means in response to a shifting movement thereof to control saidv power actuated clutch disengaging means in manner to eflect disengagement of said clutch prior to shifting of said gearing, and to eil'ect slow rotation of said gearing by said auxiliary drive apparatus during shifting thereof.

16. In a machine tool having an adjustablepower transmission mechanism including a rate changer, the combination with a clutch engageable to effect driving of said mechanism and a brake engageable to stop said mechanism, of means arranged to adjust said rate changer, means associated with said adjusting means and operative thereby in manner to automatically disengage both said clutch and said brake upon movement of said adjusting means in adjusting said rate changer, and an auxiliary drive apparatus arranged to drive said mechanism at low rate of speed when said clutch and said brake are disengaged, whereby adjustment of said rate changer is facilitated.

17. In a machine tool having an adjustable rate changing power transmission mechanism including shiftable gearing, the combination with a' main driving means including a main clutch enga'geable to drive said mechanism at normal operating speed, of an auxiliary slow speed driving means including an overrunning clutch device operatively connected in manner to drive said mechanism at low rate of speed to facilitate shifting of said gearing when said main clutch is disengaged.

18. In a machine tool having a prime mover, a spindle, and avariable speed on connected to the spindle, the combination of a clutch for coupling the n to the prime mover for actuation thereby, abrake operable by the clutch on disengagement thereof for stopping the transmission, a branch train coupled to the prime mover exclusive of the clutch, means to connect the train for slow rotation of the transmission during disengagement of the clutch, and means automatically operable upon connection of said train to release the brake.

19. A machine tool having a spindle, a variable speed shiftable gear tron therefor, a prime mover, a main clutch for coupling the prime mover to the transmission, a branch transmission continuously actuated by the prime mover, an auxiliary clutch for coupling the branch transmission to the spindle transmission when the main clutch is uncoupled for effecting slow rotation thereof during shifting of its gears, and an interlock between the main clutch and the auxiliary clutch to prevent engagement of the main clutch when the auxiliary clutch is effective.

20. In a machine tool having a transmission including an adjustable rate changer, the combination with driving means including a main clutch engageable to drive said adjustable rate changer at normal operating speed, of an auxiliary driving device including a speed reducing train and an auxiliary clutch operative when said main clutch is disengaged to drive said rate changer at a low rate of speed in manner to facilitate adjustment thereof.

21. In a machine tool having an adjustable rate changer including shiftable gearing, the combination with main driving means including a clutch engageable to drive said gearing at normal operating speed, of an auxiliary slow speed driving means arranged to function when said main clutch is disengaged and operative to drive said gearing at a predetermined low rate of speed to facilitate gear shifting.

22. In a machine tool having an adjustable transmission mechanism including shiftable gearing, driving means for said mechanism including a main clutch, a brake disposed to stop said mechanism, an auxiliary drive apparatus arranged to drive said mechanism at a low rate of speed to facilitate shifting of said gearing, a single control element arranged to effect shifting of said gearing, and means associated with said gear shifting control element for actuating both said main clutch and said brake to disengage them prior to a shifting operation and for engaging said auxiliary drive apparatus to cause said gearing to turn slowly while being shifted.

23. In a speed changing power transmission mechanism including shiftable gearing, a source of power for driving said mechanism, primary means disposed to selectively connect said source of power to said mechanism to drive it, means for shifting said gearing, and an auxiliary speed reducing drive apparatus disposed to selectively connect said source of power to said mechanism to actuate it at a low rate of speed when said primary means is disconnected to thereby rotate said shiftable gearing in manner facilitating shifting thereof.

24. In a speed changing power transmission mechanism including shiftable gearing, a source of power for driving said mechanism, a main clutch disposed to selectively connect said source of power to said mechanism to drive it, means for shifting said gearing, an auxiliary speed reducing drive apparatus disposed to selectively connect said source of power to said mechanism to actuate it at a low rate of speed when said main clutch is disengaged to thereby rotate said shiftable gearing in manner facilitating shifting thereof, and control means associated with said gear shifting means and operative to automatically disengage said main clutch and connect said auxiliary drive apparatus prior to shifting of said searing.

25. In a machine tool having an adjustable transmission mechanism including shiftable gearing, driving means for said mechanism including an auxiliary drive apparatus arranged to drive said mechanism at a low rate of speed to facilitate shifting of said gearing, and a single control element arranged to eiIect shifting of said gearing and operative to engage said auxiliary drive apparatus prior to a shifting operation to cause said gearing to turn slowly while being shifted.

26. Ina machine tool, the combination with power transmission means including a shiftable member operative to adjust the driving eflect produced thereby, of primary driving means connectible to apply power to said transmission means to drive it at normal operating speed, an auxiliary slow speed driving mechanism, means operative to disconnect said primary driving means from said transmission means, and other means operative to connect said auxiliary slow speed driving mechanism to .said transmission means in lieu of said primary driving means, whereby said transmission means may be actuated slowly to facilitate shifting of said shiftable member in executing a change in the driving ef fect thereof.

27. In a machine tool the combination of a transmission including in the order recited a constant speed power source, a shiftable interrupter clutch device and a rate changer, said rate changer including a plurality of rate change devices serially arranged and shiftable to a variety of position combinations respectively for different predetermined output speeds, speed selector means including a chart having numerical markings respectively corresponding in value to different of said speeds and indicator means movable relative to said chart, shifter means for said clutch device, shifter means for said rate change devices, shifter means for said relative chart and indicator movement, a controller combinedly operatively controlling each of said shifter means, and another controller individually operatively controlling said clutch device to alternatively interrupt or establish the driving connection of said power source and rate changer.

28. In a machine tool the combination of a transmission including in the order recited a constant speed power source, a clutch device and a rate changer, said clutch device being shiftable to alter the driving connection of said source to said rate changer, said ratechanger including a plurality of rate change devices serially arranged and shiftable to a variety of position combinations respectively for different predetermined output speeds, speed selector means including a chart having numerical markings respectively corresponding in value to different of said speeds and indicator means movable relative to said chart, shifter means for said rate change devices, shifter means for said relative chart and indicator movement, a power operable shifter for said clutch device, and a controller combinedly operatively controlling said rate change shifter, said chart and indicator shifterand the power operation of said clutch device shifter, whereby said rate change devices, shifter means for said relative chart and indicator movement. a power operable shifter for said clutch device. a controller combinedly operatively controlling said rate change shifter, said chart and indicator shifter and the power operation of said clutch device shifter, and another controller individually operable for shifting said clutch device to. alternatively interrupt or establish the driving connection of said power source and rate changer.

30. In a machine tool the combination of a transmission including in the order recited a constant speed power source, a shiftable interrupter clutch device and a rate changer. said rate changer including a plurality of rate change devices serially arranged and shiftable to a variety of position combinations respectively for different predetermined output speeds, speed selector means including a chart having numerical markings respectively corresponding in value to different of said speeds and indicator means, movable relative to said chart in accordance with the shifting of said rate change devices, shifter means for said clutch device, shifter means for said rate change devices, a controller combinedly operatively controlling both said shifters to shift said clutch shifter in advance of the other shifter,

and another controller individually operatively controlling said clutch device to alternatively interrupt or establish the driving connection of said power source and rate changer.

31. In a machine tool the combination of a transmission including in the order recited a constant speed power source, a clutch device and a rate changer, said clutch device being shiftable to alter the driving connection of said source and rate changer, said rate changer including a plurality of rate change devices serially arranged and shiftable to a variety of position combinations respectively for different predetermined output speeds, speed selector means including a chart having numerical markings respectively corresponding in value to different of said speeds and indicatormeans mdvable relative to said chart in accordance with the shifting of said rate change devices, shifter means for said rate change devices, power operable shifter means for said clutch device, and a controller combinedly operatively controlling said rate change shifter and the power connection of said clutch shifter whereby to eflect said alteration of driving connection during rate change.

32. In a machine tool the combination of a transmission including in the order recited a constant speed power source, a shiftable interrupter clutch device and a rate changer. said rate changer including a plurality of rate change devices serially arranged and shiftable to a variety of position combinations respectively for diflerent predetermined output speeds, speed selector 1. means including a chart having numerical markingsrespectivelycorrespondinginvaluctodiiferent of said speeds and indicator means movable relative to said chart in accordance with the shifting of said rate change devices, shifter means for said rate change devices, power operable shifter means for said clutch device, a controller combinedly operatively controlling said rate change shifter and the power connection of said clutch shifter. and another controller individually operatively controlling said clutch device to alally arranged and shiftable to a variety of posi-- 1 tion combinations respectively for different predetermined output speeds, said transmission also including shiftable brake means effective on some of said rate change devices. speed selector means including a chart having numerical marhngs respectively corresponding in value to different of said speeds and indicator means movable relative to said chart. shifter means for said clutch device, shifter means for said speed change devices, shifter means for said relative indicator movement. shifter means for saidbrake, a controller combinedly controlling the shifter means for said speed change devices, said relative movement and said clutch, and another controller independently operable for the control of the shifter means for said clutch and said brake.

34. In a machine tool the combination of a transmission including in the order recited a power source, shiftable interrupter means'and a rate changer. said rate changer including a plurality of rate change devices shiftable to a variety of position combinations respectively effecting different transmission speed ratios, said interrupter means having an interrupting position and a driving position effective for a normal speed drive of said rate changer from said power source, means for alternatively en'ecting a relatively low speed drive of said rate changer, selector means including a chart having markings respectively corresponding to different of said speed ratios and an indicator movable relative to said chart. control means for operation of said interrupter means, said rate change devices and said low speed drive means to shift said rate change devices to eflect a speed ratio position combination indicated by said selector means during driving of said rate changer at said relatively low speed. and control means for shifting said interrupter means alternatively to interrupting or to said normal speed driving positions without the shifting of said rate change devices.

35. In a machine tool including a transmission comprising a plurality of rate changer devices shiftable for effecting various position combinations respectively for different transmission speed ratios and including a normal speed drive means for said rate change devices comprising a shift able clutch, the combination of means for alternatively effecting a relatively low speed drive of said rate change devices, control means for operation of said clutch, said rate change devices and said low speed drive means to effect shifting of saiddevicesforachangeintransmissionratio while the rate change devices ven at said relatively low speed, and OOBUWQNM- ing said clutch independently of the of said rate change devices.

36. In a machine tool the combination of a transmission including a rate changer comprising a plurality of rate change devices shiitable to a variety of position combinations respectively eifecting different transmission speed ratios,

.means for alternative drive of said rate changer at normal or relatively slow rates including a shiftable clutch, control means for eilecting shifting of said clutch accompanied by a shifting of said rate change devices while said rate changer is driven at said relatively slow rate, and control means for shifting said clutch independ ently of the shifting of said rate change devices.

37. In a machine tool the combination of a on including a rate changer comprising rate change devices shiftable to a variety of positicn combinations respectively eilecting diilerent on speed ratios, means for altematve drive of said rate changer at normal or relatively slow rates, said drive means being adopted for interruption of the drive, control means for effecting said relatively slow rate simultaneously with theshifting of said rate change devices, and control means operable independently of the shifting of said rate change devices for alternatively eilecting said normal rate or eil'ecting said interruption.

38. In a machine tool the combination of a transmission including a rate changer comprising rate change devices shiftable to a variety of position combinations respectively eifectin'g difi'erent transmission speed ratios, a speed ratio selector including relatively movable chart and indicator means, means for alternative drive of said rate changer at normal or relatively slow rates and adopted for interruption of the drive, control means for effecting said relatively slow rate simultaneously with the shifting of said devices to eflect a speed ratio indicated on said selector means, and control means for independently alternatively efl'ecting said normal speed drive or eflecting the interruption of the drive.

39. In a machine tool the combination of a transmission including a rate changer comprising rate change devices shiftable to a variety of position combinations respectively effecting different transmission speed ratios, a speed ratio selector including relatively movable chart and indicator means, means for alternative drive of said rate changer at normal'or relatively slow rates and adopted for interruption of the drive, a brake shiftable to alternatively restrain or release at least a portion of said rate changer, control means for efl'ecting said relatively slow drive during the release position of said brake and simultaneously with the shifting of said devices to eflfect the speed ratio indicated by said selector means, and control means for alternatively eilecting said normal speed drive or efl'ecting the interruption of the drive of said rate changer during the restraining position of said brake and independently of the shifting of said devices.

40. In a machine tool having a power transmission including an adjustable rate changer, the combination with a clutch engageable to eil'ect driving of said rate changer and a brake engageable to retard said drive, of means arranged to adjust said rate changer, means associated with said adjusting means for automatically disengaging both said clutch and said brake to facilitate the rate changer adjustment, and control means for operation of said clutch and brake independently of said adjusting means.

41. In a machine tool, the combination of a r 9 transmission including .an adjustable rate changer, drive means therefor including a driving clutch and a brake, means shiftable to selectively connect said rate changer with said clutch or with said brake or to disconnect said rate changer from both said clutch and said brake, means for shifting said shiftable means including a power train, adjusting means for said rate changer, and means associated with said adjusting means and controlling said power train for effecting disengagement of both said clutch and said brake to facilitate the rate changer adjustment.

42. In a machine tool the combination of a transmission including in the order recited a constant speed power source, a clutch device and a rate changer, said clutch device being shiftable to alter the driving connection of said source and rate changer, said rate changer including a plurality of rate changer devices serially arranged and shiftable to a variety of position combinations respectively for different output speeds, speed selector means including a chart having numerical markings respectively corresponding in value to diflerent of said speeds and indicator means movable relative to the chart, shifter means for said rate change devices, power operable shifter means for said clutch device, and control means including means combinedly operatively controlling said rate change shifter and the power connection of said clutch shifter and means for independent control of said clutch for alternative engagement or disengagement I thereof.

43. In a machine tool the combination of a transmission including in the order recited a power source, a brake device, and a rate changer, said brake device being shiftable to alternative engaged and disengaged positions, said rate changer including a plurality of rate change devices serially arranged and shiftable to a variety of position combinations respectively for diil'erent output speeds, speed selector means including a chart having numerical markings respectively corresponding in value to diflerent of said speeds corresponding in value to different of said speeds and indicator means movable relative to said chart, shifter means for said rate change devices, shifter means for said brake, control means combinedly controlling said shifters whereby to effect a disengaged position of said brake during rate change, and means for independent control of said brake shifter means foreflecting said alternative engaged or disengaged positions of the brake.

45. In a machine tool the combination of a transmission including an adjustable rate changer, driving means for said rate changer including a clutch shirtable to alternative driving .9 and interrupting positions, adjusting means for said rate changer including a member alternatively positionable to render said adjusting means operable or inoperable, and means for shifting said clutch to interrupting position during the positioning of said member for rendering said ad-.- justing means operable.

46. In a machine tool the combination or a transmission including an adjustable rate changer, driving means for said rate changer including a clutch shiitable to alternative driving and interrupting positions, adjusting means for said rate changer including a member alternatively positionable to render said adjusting means operable or inoperable. means for shifting said clutch to interrupting position during the positioning or said member for rendering said adjusting means operable, and meansi'or shitting said clutch independently of said adjusting means.

47. In a machine tool the combination or a ton including in the order recited a power source, a clutch alternatively shii'table to driving and interrupting positions, and a rate changer including a plurality of rate change devices serially arranged and adjustable to a variety of position combinations respectively for diflerent output speeds, speed selector means including a chart having numerical markings respectively corresponding in value to different of said speeds and indicator means movable relative to said chart, adjusting means for said rate changer including a member alternatively positionable to render said adjusting means operable or inoperable, and means preventing said clutch from occupying said driving position when said member is positioned iorrendering said adjusting means operable.

' erase isrlnamachinetooltbecombinationoia transmission including in the order recited a power source, a clutch alternatively shirtablc to driving and interrupting positions, and a rate changer including a plurality of rate change devices serially arranged and adjustable to a variety of position combinations respectively for diflercut output speeds, speed selector means including a chart having numerical markings respectively corresponding in value to dliierent of said speeds and indicator means movable relative to said chart, adjusting means for said rate changer including a member alternatively positionable to render said adjusting means operable or inoperable, means preventing said clutch irom occuwing said driving position when said member is positioned for rendering said adjusting means operable, and means for shifting said clutch independently of said adjusting means.

49. In a machine tool having a tool support and a work support the combination oi a transmission ior relative movement or said support including a rate changer adjustable for a series of predetermined rates, drive means for alternatively actuating said rate changer at normal or relatively slow rates, said drive means being operable to interrupting the rate changer drive, and control means for said transmission including means for adjusting said rate changer to eii'ect one or anotlier or said predetermined rates, means interoperative with said adjusting means to eii'ect said relatively slow drive rate during operation of said adjusting means, and meansindependently controlling said drive means to alternatively eilect said normal rate or the interruption or the rate changer device.

WALTER M. POHL. JOSEPH B. ARMITAGE.

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