US2248485A - Lubricating device for machine tools - Google Patents

Description

A. F. BENNETT ETAL Filed Nov. 10, 1937 4 Sheets-Sheet 1 LUBRICATING DEVICE FOR MACHINE 'TdOLS m3 NmN umw mmN k m @Lw NbN NR mQN QNN. .MQN. .QQN mww 7. NA Nun Inventam m wk 4 Q www F July 8, 14L

4 sheat s-Sheet 2 v 0 In ent m rrr Filed Nov. 10, 1937 A. F. BENNETT ETAL. LUBRIGATING DEVICE FOR MACHINE TOOLS July 8, 1941.

July 8, 1941. A. F. BENNETT ETAL LUBRICATING DEVICE FOR MACHINE TOOLS Filed NOV. 10, 1937 4 Sheets-Sheet 3 www QM |4l|| llllllllllllllll July 1941. A. F. BENNETT ETAL LUBRICATING DEVICE FOR MACHINE TOOLS 4 Sheets-Sheet 4 Filed Nov. 10, 1937 Patented July 8, 1941 UNlTED STATES PATENT orrice f I LUBRICATING DEVICE FOR MACHINE TOOLS Arthur F. Bennett, West Barrington, R. I., and George F. Maglott, Wrentham, Mass., assignors to Brown and Sharpe Manufacturing Company, a corporation of Rhode Island Application November 10, 1937, Serial No. 173,850

Claims. {Cl- 184-6) H y i I machine, a portion of the knee'casing'having The present invention relates to improvements in lubricating devices for machine tools, and more particularly to means Well adapted for lubricating certain moving parts of a milling machine of the general type having a longitudinally reciprocable work table, a transversely movable saddle support, and a vertically adjustable knee support. I

It is an object of the present invention to provide a novel lubrication system of the non-return type which is well adapted for supplying lubricant economically and efiiciently to the various moving parts mounted in the vertically adjustable knee of a milling machine.

More specifically, it is an object of the inven tion to provide a lubricating system of this general description which is Well adapted to provide intermittent lubrication under pressure to the various moving parts at intervals which will bear a definite relation to the extent and character of the machine operation toinsure an adequate but not excessive supply of lubricant to the moving parts, and in which the amount supplied will be substantially equal to the amount of oil consumed or lost incidental to the use of the machine.

It is another object of the invention to provide a device for controlling the operation of a machine tool pressure lubricating system which is well adapted for automatic operation to supply a limited amount of lubricant to the operating parts only when the machine is returned to active operation after a substantial period of rest.

While the several features of applicants invention are hereinafter disclosed, and are of particular value as applied to the lubrication of the moving parts in the knee of a milling machine, it will be understood that the invention in its broader aspects is not limited in its application to the specific machine or parts thereof herein disclosed, and that the lubricating system hereinafter described, may be equally well applied to provide automatic lubrication for other movin parts and for other types of machine tool.

With the above noted and other objects in view, as may hereinafter appear, the several features of the invention consists in the devices, combinations and arrangement of parts hereinafter described and claimed, which together with the advantages to be obtained thereby, will be readily understood by one skilled in the art from the following description taken in connection with the accompanying drawings, in which Fig. 1- is a view in left side elevation illustrating particularly the vertically adjustable knee of a milling been broken away, and certain of the underlying parts being shown in section to illustratethe em: bodiment of applicants lubricating devices in the machine; Fig. 2 is an enlarged detail sectional view of the oil pump and connections therefrom shown in Fig. 1; Fig. 3 is an enlarged detail sec'-' tional view of the automatic oil feed control valve shown in Fig. 1; Fig. 4 is an enlarged view front elevation of substantially the parts shown in Fig. l, to illustrate particularly the application of applicants lubricating system to the movin parts in the knee and feedbox of the machine; Fig. 5 is a sectional view taken on the line55, of Fig. 4, to illustrate certain of the driving con'- nections mounted in the knee; Fig. 6 is a detail view, partly in section, taken on the line 6-6 oi Fig. 4, to illustrate particularly the pipe connections for lubricating the cross feed screw clutch and bearing surfaces associated therewith; Fig. 7

is a detail plan view partly in section, taken 'on the line 'l'l of Fig.4, illustrating the kifee 'ele' V vating shaft and the conduits through which lubricant is supplied thereto; Fig.8 is a sectional view in left side elevation taken on the line 8-8 of Fig. 4, and illustrating particularly 'thecon-i nections for lubricating the bearingsand'other moving parts in the feed box;' and Fig. 9 'isfa' plan view of substantially the parts shown in Fig. 8.

The invention is disclosed in the drawingsjin a preferred form, as embodied in a milling "ma chine of the general type having a Vertically extending column supporting a milling cutter spindle, and a work supporting assembly includ-'. ing a longitudinally movable table, a transversely movable saddle support, and a vertically adjust ableknee. Only so much of themaohine isil lustrated as is believed necessary to iHuStrate'the application of applicants improve'dlubricating system to the moving parts mountedin' the knee sup-port and in the feed box, which is, mounted to form an integral unit therewith. .j 1

The drawings disclose a vertically adjustable knee support 29 which is supported forvertical movement with relation to a machine column?! generally indicated in Fig. 1, on waysf'2fl, and a transversely movable saddle support 26 carried on ways 21 formed on the upper side ofthe knee. For a more complete illustration orthe saddle support 26 andwork supporting. table, not here shown, together with portions of the driv ing transmission for operating the tabl'e,ri'er+ ence may be had to the copending application of the present applicant Bennett, Serial Nofl'lb;

851, filed November 10, 1937, of even date herewith upon which has issued Patent No. 2,190,858, dated February 20, 1940. The power drive for the table, saddle and knee transmissions, is taken from a vertically extending drive shaft 28 (see Fig. 8) which may be regarded as the prime mover and is mounted in the machine column 22. From the drive shaft 28, the drive is taken through a bevel gear 30 splined thereto, and connected through a bevel gear 32 to a gear 34 secured to a drive shaft 36 in a feed box 38 which is formed integrally with the knee support 20. A second gear 40 on the shaft 38, meshes with a gear 42 forming part of an overrunning device through which is driven a shaft 44 and gear 46. The gear 46 meshes with an idler gear 41 carried on a stub shaft 48, and through this gear drives a cam driving gear 49 and a forwardly extending drive shaft 50 secured thereto, mounted .in the knee support 20. The branch transmissions utilized for power operation of the i'ndiv'idualknee, saddle and table supports, and forpower'operation' of the lubrication devices hereln'described, are taken directly-from the gear "and shaft 50 which, therefore, form the main stenrofthe driving transmissions for these parts.

Referring'particularlyto Fig. 8, itwill be seen that the splinegear30 is-externally supported in abearing 52 formed in an extension 54 of the feed'b'ox' casing'38 which also provides a pivotal bearlngsupport 56 for the intervening bevel ge'ar'32. Bearing supports 58 and 60 are providedfor the intermediatedrive shaft 36, bearings 62and'B4' are provided for the overrunning clutch shaft 44'andbearings 66 and 68 for the idler gear shaft 48.

.Thetable support (not shown) is driven from the shaftifl through a branch transmission which comprisesa bevel gear splined to the shaft 50;and arranged'to mesh with a gear 12 at the lower en'dof an upwardly extendingdrive shaft 14? The bevel gear 10 is externally supported in a downward extension of a housing I6'for the'shaft "which is secured to the under side of "the saddle support 26, so that these parts aremovable'asa' unit with the saddle axially Of' the" shaft 50.

' The saddle support 26 is power operated from the shaft 50 through a branch transmission comprising a screw shaft I8 which is screwthreaded into a nut 80 formed in the housing 16, and is supported at its forward end in a bearing 82 (see Fig. 6) in the knee support 20. The screw shaft I8 may bedriven from the shaft 50through connections which include a gear 84 sleeved on the shaft I8, and a driving gear 88 supported co-axaially with the shaft 50, and arranged. to be driven therfrom through reversing a'tidclut'chin'g devices hereinafter more fully set forth; As' best shown in Fig. 6, the gear 84 is carriedon a clutch'sleeve B8 loosely supported on'theshaft 18;ar'1d is connectible to drive the shaft 18 through the engagement of clutch sur faces 90 formed on adjoining portions of the clutch sleeve 88 and a collar 92 secured to the shaft I8. v

For effecting a power adjustment of the vertical position of the knee support 20, an'additional branch transmission is provided which may be driven from the shaft 50, and comprises a drive shaft 94 which is located parallel to and beneath the'shaft 50, and at its rear end carries a bevel gear fifiwhich'meshes with a gear 98 rigidly secured to the upper end of theusual knee adjusting screw|00. The shaft 94 is driven from the reversing gear I02.

the shaft 50 through driving and reversing connections which include a reversing sleeve gear I02 which is splined to the shaft 50, and is axially movable thereon between the position shown in Fig. 5, in which it is operatively connected to drive the gear 86 sleeved thereon through the engagement of the face clutch surfaces I04, as shown in Fig. 5, and an alternative position in which it is moved to the left, causing the clutch I04 to be disengaged, in which the gear I02 meshes with an idler reversing gear I06 (see Fig. 1) carried on a stub shaft I08. A shifting yoke generally indicated at I09 in Fig. 1, provides a convenient means for controlling the position of The gear I06 meshes with agear IIO supported on a sleeve member II2 splined to and axially shiftable on the shaft 94. 'I'hesleeve II2 also carries a gear II4 which meshes with the drive gear 86, and is arranged through the engagement of clutch surfaces II6 formedrespectively onthe sleeve H2 and on a'col1ar-II8 onthe shaft 94 to be operatively connected to drive the shaft 94.- A shifting yoke generally indicated at I20 in Fig; 5, is provided forshiftingthe sleeve member II2 axially to engage-or disengagethe clutch H6.-

Manual operation of-- the driving screw-I8 to effect adjustment in the position of the saddle support 26,-is-eifected bymeans of a handwheel I2I-(Fig.' 6) -whichis operatively' connected to the forward endof the-screw shaft '10; Manual operation of the adjusting-screw I00'for raising andlowering the kneesupport 20,- is effected through connections which; as-bestshown in Figs; 1 and 7, includes. hand wheel I22 operatively-connected to'one end-of-a horizontally extending shaft I23 whichis supported in bearings I24 and- I25 on theknee 20, and has secured to therearendthereofa bevel gear I26 which meshes with beve1gear 98 secured to the upper end of the vertical adjustlngscrew I00.

Withtheconstruction and arrangement of the driving andreversing mechanism for the knee and-saddle branch transmissions above set forth, it will readily be seen that the drive for power operation of these parts, is taken from the-shaft 50onto the reversing clutch'gear- I02, and thence through-ithe clutch I04 and gear 06 directly to the respective shafts l8- and 94; or alternatively from the gear I02 onto'the idler reversing gear Iflfi thence through gear IIO, sleeve "H2 and gear'lI l-which -rneshes with andoperates to drive thegear flfidn-the opposite direction; Inasmuchas the mechanism for shifting the reversing gear I02 and for operatively engaging and disengagingthe clutch connections tothe saddleand-knee branch transmissions, form no partspecifically ofthe-present invention, no specific description orillustration thereof is considered-necessary: f In'carrying" out the present invention, a lubrication system of the non-return type is provided for automatically maintaining an adequate lubrication'ofthe moving parts which are mounted inftheknee-and adjoining feed box; and are comprised 0f"t1 1 e transmission trains" for the tabIeZsaddIeand knee. 'Applicants lubricating system 'takes'the form of a self-contained unit mounted-in the kneaand is' constructed and arranged'to supply lubricant to the several moving parts mounted 'in the knee and feed box in relatively small amounts; and at intervals which will bear a definite relation to the extentand character of the-machine-oprationi- It'has been found; particularly when the machine is allowed to stand idle for any substantial period of. time, that the lubricant adhering to the bearing surfaces, tends to drain 01f, and also as the machine continuous or substantially continuous use of the machine.

In accordance with the ideas above expressed, applicants have provided a self-contained lubricating system mounted in the knee which includes a reservoir I30 mounted on the knee support 20, a pump generally indicated at I32 driven from an eccentric cam I34 formed integrally with the constantly driven gear 49 on the shaft 50, a system of conduits through which lubricant is distributed in proportionate amounts to the several bearings and other parts to be lubricated, together with a time delay control valve I36 which is operative to cause a limited amount of lubricant to be forced through the lubricating system in starting the machine only after a substantial period of inactivity.

Referring specifically to Figs. 1 and 2 of the I drawings, the pump I32 comprises a casing supported within the reservoir I30 and having formed therein a central bore I40 adapted to receive a piston I42 forming the lower end of an actuating plunger I44 which extends upwardly through a bore I46 in the cover plate I48 of the reservoir I30, and at its upper end engages against the eccentric driving cam I34. A compression spring I50 coiled about the plunger I44 between a collar I52 and an abutting portion of the pump casing I32, maintains the piston I42 and plunger I44 in engaging contact with the cam I34. Lubricant is admitted into the pump chamber I40 through a filter I54 and a check valve I 56 during the upward stroke of the piston I42, and during the return or down stroke of the piston I42, is forced out of the chamber I40 through a check valve I58 and a conduit I60 to the time delay valve I36 above referred to, and

I80, I82, and I84. Lubricant passes from the distributing head I68 through a drip plug I 88 and conduit I10 into a centrally located bore I90 in the supporting shaft I08 for the idler reversing gear I06 (see Fig. 1), and thence through a radial outlet to the gear bearing, a second branch conduit I9I providing lubricant to the front bearing for the knee power drive shaft 94. Lubricant is directed from the distributing head I68 through conduit I12 to a subsidiary distributing head I96 located in the feed box 38, being distributed thence through additional branch conduits to lubricate the several moving parts in the feed box, as hereinafter more fully set forth. Lubricant is directed through conduit I14 and a drip p1ug. I98 connected therein (see Fig. 1) to the rear bearing I99 for the main drive shaft 50. The conduit I16 and a drip plug 200 associated therewith, are arranged to direct lubricant to the bearing support for the hand elevating control shaft I23 (see Figs. 1, 4 and 1)., The conduit I18 and a drip plug 202 associated therewith, are arranged to supply lubricant to the rear bearing support 283 for the power knee elevating shaft 94 (see Figs. 1, 4 and 5). The conduit I80 having a drip plug 286 associated therewith, is connected into the conduit I12 (see Fig. 4), and is arranged to direct lubricant to the front bearing support 82 for the cross feed screw shaft 18, and thence through a branch conduit 208 to the clutch sleeve member 88 supported on the shaft 18 (see Fig. 6) The conduit I82 and a drip plug 2 I 0 associated therewith, serve to direct lubricant to the upper end of the elevating screwI00, and thence through branch conduits to the several bearing surfaces associated With thescrew shaft I00 including the threaded portion thereof. The

a to the passing of lubricant therethrough, so that thence through the operation of the valve I36,

as hereinafter more fully set forth, is either returned to the reservoir I30 through an exhaust outlet I6I and return conduit I62, or is alternatively directed through an outlet I64 and a conduit I66 to a main distributing head I68 to effect the lubrication of the several operating parts. An oil gauge I61 mounted on the side of the knee, and connected through a conduit I69 with the conduit I66 (see Fig. 1) provides a direct reading of the lubricant pressure in the distributing system hereinafter described.

The distributing system through which lubricant is directed in proportional amounts to the several moving parts located in the knee support 20 and feed box 38, may be briefly described with reference to the drawings as follows: The distributing head I68 is provided with a number of outlets, each having a drip plug and a branch conduit connected thereto, through which lubricant is directed to each of a number of lubricating stations. The several branch conduits are designated respectively at I10, I12, I14, I16, I18,

lubricant will be distributed to the several operating parts in properly proportioned amounts which may be readily determined in accordance with the requirements of the particular hearings or other parts to be lubricated.

In order to provide for lubrication of the several bearings in the feed box 38, lubricant supplied to the subsidiary distributing head I96 through conduit I12, is redistributed in proportional amounts through a number of branch conduits numbered respectively 220, 222, 224, 226, 228, 230, and 232, to a number of lubricating stations in the feed box. As best shown in Figs. 8 and 9 of the drawings, lubricant supplied under pressure to the subsidiary distributing head I36, is directed through the conduit 220 and an associated drip'plug 234 to a bore 236 in the bracket 54, from which it passes to the bearing support for the gear 32, and to the rear bearing for the drive shaft 38. Lubricant under pressure is directed through the conduit 222 and an associated drip-plug 238 to the bearing support 52 for the spline gear 30 on the drive shaft ciatedtherewith, serve to direct lubricant to the rearbearing 64 for the overrunning clutch drive I Similarly, the conduits 226, 228 and 230 having drip plugs connected therein, serve The conduit 224 and a drip plug 240 asso to supply lubricant respectively to the front bearing 58 for the shaft 36, to the bearing 66 for the shaft 48, and to the bearing 62 for the shaft 44. The conduit 232 and a drip plug 244 connected therein, provide an additional outlet through which lubricant is permitted to drip onto certain other moving parts (not shown). It will be understood that each of the drip plugs associated with the several conduits leading from the secondary distributing head I96, is constructed and arranged to provide a predetermined resistance to the passage of lubricant therethrough, so that lubricant will be distributed to the several operating parts in properly proportioned amounts, which may be readily determined in accordance with the requirements of the particular hearings or other parts to be lubricated.

In accordance with a principal feature of the present invention, applicants time delay valve I36 above referred to, is provided for controlling the admission of lubricant under pressure into the distributing system from the pump I32, which is continuously driven during power operation of the table, saddle and knee transmission. The valve I36, as hereinafter more fully pointed out, is constructed and arranged to introduce a suificient quantity of lubricant into the system to provide a thorough lubrication of all the lubricating parts in starting the machine, and thereafter to shut off the supply. To this end, applicants valve I36 is arranged to be controlled directly by variations in pressure existing in the system, operating to shut off the supply only after the pressure in the distributing system has been built up to a point which will insure a thorough lubrication of the several operating parts.

The construction and operation of the valve I36 will be best understood in connection with Fig. 3 of the drawings. The valve comprises the casing 269 and a plunger 250 which is supported for axial movement in a cylindrical bore 252 in the casing. Movement of the valve member 250 to the left is limited by engagement with a plug 254 in which is formed an inlet port 256 for the conduit I60. The valve member 250 is yieldingly maintained in its extreme position to the left by means of a compression spring 258, which is seated at one end in the recess 260 in the plunger 250, and at its other end in a plug 262'screwthreaded into a threaded portion of the bore 252. It will readily be seen that adjustment of the pressure exerted by the spring 258 is readily obtained by an adjustment in the position of the plug 262. The valve member 250 has formed therein a central bore 266 which connects at one end with the inlet 256 and conduit I60 for the admission of fluid underpressure from the pump I32. At its opposite end the bore 264 is connected by means of a number of radial ducts 266 with a peripheral groove 268 in the valve member 250, which provides connection with the outlet I64 and conduit I66 to the main distributing head I68 for the position of the parts shown in Fig. 3. Movement of the valve member 250 to the right, as hereinafter more fully set forth, operates to close off the outlet IE4, and to align the peripheral groove 268 with the exhaust outlet I6I and return conduit I62 to the reservoir I30. I

The operation of applicants time delay valve I36- may be briefly described as follows: Assuming that the machine is in its stop position, and that the valve member 250 is in its position to the extreme left as shown in Fig. 3, the starting of the table transmission including the gear 49 and shaft 50, will start the pump I32. Lubricant under pressure is now forced through the conduit I- and through the axially extending bore 264, radialducts 266 and groove 268 to the outlet I64, and thence through the main distributing head I68, from which lubricant is now supplied, as above set forth, in proportional amounts to the several operating parts of the machine. In this manner, a substantially continuous flow of lubricant under pressure is maintained to the several lubricated parts until a substantial amount of back pressure has been built up in the system. As soon as this happens, the valve member 250 is forced to the right against the pressure of its spring 258, thus closing off the outlet I64 and opening the exhaust outlet I6I, so that all of the lubricant forced into the valve I36 by the pump is now returned to the reservoir I30. It will readily be seen that the valve member 250 will now be continuously maintained in a position to the right due to the pressure maintained by the pumping unit I32; so that no further lubricant will be supplied to the machine parts during continued machine operation. It will also be evident that upon stopping of the machine, no change will be effected immediately in the position of the valve member 250, since lubricant is locked in the supply conduit I60 through the operation of the check valve I 58; so that the spring 258 is ineffective to return the plunger 250 to the left. However, in the course of time, assuming a certain amount of leakage between the plunger 250 and the cylindrical bore 252, the lubricant will be permitted to gradually drain outwardly through the radial ducts 266 and peripheral groove 268 passingbetween the bearing surfaces provided by the valve member 250 and bore 252, and thence through the outlet I6] and return conduit I62 back to the reservoir I30. As lubricant is permitted to escape in this manner, the spring 258 will gradually return the plunger 250 to the left until it finally reaches again the position shown in Fig; 3. The rapidity with which this return action takes place will, of course, be determined by the amount of the clearance which exists betweenthe valve member250 and bore 252, and upon the adjustment of the spring 258. While applicant does not propose to limit himself as to the lengthof the delay period in which the machine may again be started Without causing an additional shot of lubricant to be distributed to the several bearings, it has been found desirable to adjust the valve I36 so that a period of inactivityamountingto the betterpart of an hour, must elapse before the valve member 250 will have returned to the operative position shown in Fig. 3.

It will be understood that the invention is not limited to the specific embodiment shown, and that various deviations may be made therefrom Without departing from the spirit and scope of the appended claims.

What is claimed is:

l. A device for lubricating the moving parts of amachine tool which comprises means for supplying lubricant under pressure, means operative in starting and stopping said parts to start and stop *said' pressure supply means, a conduit through whichlubricantsupplied under pressure is} directed to the'parts to be lubricated, a control valve'in' said conduit comprising means responsive to' variations in pressure for movement between open and'shut-off positions, actuable by the building up of pressure of lubricant forced through the conduit to the parts to be lubricated in starting said parts to shut off the supply of lubricant, and pressure exhaust means operative in stopping said parts to gradually exhaust said pressure and thereby to permit the valve connection-between the pressure supply means and said parts to open only after a substantial period of inactivity of the parts.

2. A device for lubricating moving parts in a machine tool which comprises means for supplying lubricant under pressure, means operative in starting and stopping said parts to start and stop' said pressure supply means, a conduit through which lubricant supplied under'pressure is directed to the parts to be lubricated, and a control valve in said conduit comprising a valve member and tensioning means acting thereon responsive to variations in pressure for movement between open and shut-off positions, actuable by the building up of pressure in the conduit to shut off the supply of lubricant to the parts, and actuable by the stopping of 'the pressure supply means to permit the valve to open, and means to retard the movement of the valve member to open position whereby the valve is opened only after a substantial period of inactivity of the parts.

3. A device for lubricating moving parts in a machine tool which comprises means for supplying lubricant under pressure, means operative in starting and stopping said parts to start and stop said pressure supply means, a conduit through which lubricant supplied under pressure is directed to the partsto be lubricated, a control valve in said conduit having means responsive to variations in pressure for movement between open and shut oiT positions, actuable by the building up of pressure in the conduit to shut off the supply of lubricant to the parts, and actuable by the stopping of the pressure supply means to l permit the valve to open, and means for retarding the return movement of the valve to open position.

4. A device for lubricating the moving'parts in a machine tool which comprises means for supply lubricant under pressure, means operative in starting and stopping said parts to start and stop said pressure supply means, a conduit through which lubricant supplied under pressure is directed to the parts to be lubricated, a control valve in the conduit responsive to variations in fluid pressure for movement between open and exhaust positions, an exhaust connection to the control valve, and means in the control valve operative in starting said parts to supply a limited quantity of lubricant thereto, and thereafter to by-pass lubricant under pressure to the exhaust connection, and means including a leakage exhaust connection operative in stopping said parts to permit the valve to return to open position only after a substantial period of inactivity of said parts.

5. A device for lubricating moving partsin a machine tool which comprises means for supplying lubricant under pressure, means operative in starting and stopping saidparts to start and stop said pressure supply means, a conduit through which lubricant supplied under pressure is directed to the parts to be. lubricated, a control valvein saidconduit having means responsive to variations-in pressure for movement between open and shut-ofi positions, actuable by the building up of pressure in the conduit to shut off the supply of lubricant to the parts, and actuable by a reduction of the supply pressure upon the stopping of the pressure supply means to permit the valve to open, a check valve in the supply movement of said parts for supplying lubricant under pressure, a conduit through which the'lubricant is directed to the bearing surfaces, means to prevent the reverse flow of lubricant out of said conduit, and a control valve in the conduit having an exhaust connection thereto, a valve member having an operative position in which lubricant is permitted to pass through the conduit and the exhaust connection is shut 01f, and an alternative closed position in which the portion of the conduit extending to the lubricated parts is shut off, ,and the lubricant is exhausted through said exhaust connection, tensioning means tending to maintain the valve member in operative position, means responsive to the building up 'of pressure in said conduit for moving the valve member to closed position, and means including a leakage connection operative upon shutting off of the supply pressure for gradually exhausting said pressure to retard the return of the valve member under the influence of said tensioning means to operative position.

7. A device for lubricating a machine tool transmission having a plurality of moving'parts, which comprises means for supplying lubricant under pressure, means operative in starting and stopping said parts to start and stop said pressure supply means, a distributing system including a distributing head and conduits therefrom constructed and arranged to distribute'proportional amounts of lubricant to the partsto be lubricated, a control valve connected between the lubricant supply means and said distributing head responsive to variations in pressure for movement between open and shut-offpositions. including a valve member and tensioning means urging said valve member toward open position, actuable by the building up of pressure in the distributing head to shut off the supply of lubricant to the parts, and actuable by a reduction of the supply pressure upon the stopping of the pressure supply means to permit the valve to open, and lubricantpressure exhaust means in.- cluding means operative upon stopping said Pressure supplymeans to gradually exhaust said lubricai'it under pressure to permit'the gradual re.- turn of the valve member to open position only after a substantial period of inactivity of the parts.

8. A device for lubricating moving parts housed in the knee support of a milling machine having a work supporting assembly including relatively movable table, saddle and knee supports and motion transmitting devices for said supports including a power driving element and a plurality of associated moving parts mounted in the knee, which comprises a reservoir in the knee, a pump connected to be driven by said driving element for forcing lubricant under pressure from the reservoir, a conduit through which lubricant supplied under pressure is directed for lubricating said moving parts in the knee, and a control valve insa-idconduit responsive to variations inpressurefor movement between open and shut-ofl positions comprising a valve member and ten- ,sioning, means urging said valve member toward openposition against said lubricant pressure ac- ,tuable.instartingsaid driving element to supply a limited quantity'of lubricant under pressure to said parts, and thereafter to shut oil the supply of lubricant, and lubricant pressure exhaust means including means operative upon stopping said xlriving element and pump driven thereby to gradually exhaust said lubricant under pressure to-permit the gradual return of the valve memher to ,open' position only after a substantial period of inactivity of the moving parts.

9. A device for lubricating moving parts housed in lthejknee supportof a milling machine having a work supporting assembly including relatively movable tablesaddle and knee supports, and motion transmitting :devices for said supports including aap'ower driving element and a plurality of associated moving parts mounted in the knee, which, comprises areservoir in the knee, a distributing System including a distributing head an'didconduits 'for distributing proportional amou'nizsofflubricant to the lubricated parts, a pump operative for'forcing lubricant under pressureifriom'thereservoir to the distributing head, connections from-the driving element for continuously operating the pump, and a valve responsive'to variationsin pressure for controlling thegadrnission of lubricant from the pump to the distributingqhead, comprising a valve member responsive to the'building up of pressure in said distributing; system for, movement from an open to .ashuteofi position, means urging the valve memberztoward open 'position and lubricant pressure exhaust, means including means operative upon stopping of the driving element and pump driven thereby to, gradually exhaust said lubricant under pressurelto permit a gradual return of the valve member to open position only after a-substantial periodrof inactivity of the parts.

10. .Adevice, for lubricating moving parts housed in-the knee-support of a, milling machine having a workrsupporting assembly including relatively mova'ble'atable,saddleand knee supports, and mo- =tionitransmitting devices for said supports in- .clu'dinga driving element and a plurality of associated moving parts mounted in the knee, which comprises a reservoir in the knee, a distributing system inoludinga distributing head and conduits for distributing proportional amounts of lubricantrto thejlubricated parts, a pumpoperative to force'lubricant under pressure from the reservoir toithldistributing head, connections from the driving element for continuously operating the pmnpgnnd a valve responsive to variations in pressureifor controlling the admission of lubriant. from the pump to the distributing head, comprising means actuable by the building up of .pressureflin'said distributing system to shut off :th'e'supplyof lubricant to the distributing head, and'ac'tuablebya-reduction of the supply pressurebuponthe-stoppmg of the driving element andzpump driven thereby to permit the valve to open,- 'and means for exhausting lubricant from .thenontrolvalve at a slow rate whereby the valve isipermitted ltoreturn' to open position only after .azprcdeterniined period of inactivity of said drivsing element.

- :ai lhiA :Idevice .for lubricating moving parts ho'usedi'inthe knee support and associated feed box ofcaimilling machine-having a work supporting assembly including relatively movable table,

parts carried by the knee, a second distributing head, and conduits therefrom for distributing proportional amounts of lubricant to the moving parts in the feed box, a pump through which lubricant is directed underpressure from the reservoir to the :first and second distributing heads, connectionsfrom said power driving element for continuously operating the pump, and a control valve between the pump and said distributing headscomprising means responsive to variations inpressure, actuable by the building up of pressure in saiddistributing system to shut oil the supply of lubricant to the distributing heads, and means operative to re-open the valve only after a predetermined period of inactivity of said power driving element and pump driven thereby.

12. A device for lubricating the moving parts in a machine tool which comprises means for supplying lubricant under pressure, means operative in starting and stopping said parts to start and stop said pressure supply means, a conduit through which lubricant supplied'under pressure is directed to the parts to be lubricated, and a control valve in said conduit including a valve member responsive to the building up of pressure in the conduit for movement from an openv to a shut-oil position, means urging the valve member toward open position, and lubricant pressure exhaust means including means operative upon stopping said-pressure supply means to gradually exhaust said lubricant under pressure to permit the gradual return of the valve member to open position only after a substantial periodof inactivity of the parts.

13. A device for lubricating the moving parts in a machine tool which-comprises means for supplying lubricant under pressure, means operative in starting and stopping said parts to start and stop said pressure supply means, a conduit throughlwhich lubricant supplied under pressure is directed to the parts to be lubricated, and a controlvalve in said conduit including a valve member responsive to the building up of pressure in the conduit for movement from an open to a shut-off position, means yieldingly urging the valve member, toward open position, means operative upon stopping said pressure supply means to retain the lubricant under pressure in the conduit, and fluid pressureexhaust means including .a leakage connection for exhausting said lubricant under pressure to permit the gradualreturn of the valve member to open position only after a substantial period of inactivity of the parts,

,14. A, device for lubricating the moving parts in a machine tool which comprises means for supplying lubricant under pressure, means operative in starting and stopping said parts to start and stop said pressure supply means, a conduit through which lubricant supplied under pressure is directed to the parts to be lubricated, and a control valve in said conduit including a casing having at oneend apressure inlet port and pressure outlet and exhaust portS spaced in that order from the inlet port, and including a valve member slidable in the casing having a conduit extending axially from the end of the valve member connecting with the inlet port, and a radially exposed extension of said conduit connecting alternately with said pressure outlet and pressure exhaust ports, tensioning means urging the valve member toward open position connecting the inlet with the pressure outlet port, means to prevent reverse flow of lubricant from the inlet port upon stopping said pressure supply means, the valve member having a leakage connection between said conduit and the exhaust port whereby the valve member is permitted to return to open position under the influence of said tensioning means only after a substantial period of inactivity of the machine parts.

15. A device for lubricating the moving parts in a machine tool which comprises means for supplying lubricant under pressure, means operative in starting and stopping said parts to start and stop said pressure supply means, a conduit through which lubricant supplied under pressure is directed to the parts to be lubricated, a control valve in said conduit including a cylindrical casing having at one end thereof a pressure inlet port and pressure outlet and pressure exhaust ports spaced in that order from the inlet port, and including a valve member slidable within the casing having a conduit extending axially from the end of the valve member connecting with the inlet port, and radially exposed extensions of said conduit connecting alternately with said pressure outlet and. pressure exhaust ports, tensioning means urging the valve member toward open position connecting the inlet with the pressure outlet port, a check valve in the supply side of the conduit from the control valve to prevent reverse flow of lubricant in the inlet port, said valve member having a loose fit with the casing to provide a leakage connection operative upon stopping of the pressure supply means to permit the gradual exhaust of said lubricant under pres sure and the return of the valve member to open position only after a substantial period of inactivity of the machine parts. 7

ARTHUR F, BENNETT. GEORGE F. MAGLOTT.

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