US2472967A

US2472967A - Drilling machine

Info

Publication number: US2472967A
Application number: US323648A
Authority: US
Inventors: Goldberg Herman
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-03-13
Filing date: 1940-03-13
Publication date: 1949-06-14
Anticipated expiration: 1966-06-14

Description

June 14, 1949. H. GOLDBERG 2,472,967

DRILLING MACHINE Filed March 13', 1940 10'Sheets-Sheet 1 ATTORNEYS.

H. GOLDBERG DRILLING MACHINE June 14, 1949.

10 Sheets-Sheet 2 Filed March 13, I940 INVENTOR.

if i

June 14, 1949. H. GOLDBERG DRILLING MACHINE 1o Shee'ts-Shee t s Filed March 1-3, 1940 INVENTOR.

w MA a m June 14, 1949.

H. GQOLDBERG 2,472,967

DRILLING MACHINE Filed March 13, 1940 10 Sheets-Sheet 4 A TTORN E Y.

BY Z 3422 June .14, 1949.

Filed March 13, 1940 H. GOLDBERG DRILLING MACHINE 10 Sheets-Sheet 5 1N VENT OR.

ATTORNEYS.

H. GOLDBERG DRILLING MAbHINE June 14, 1949.

10 Sheets-Sheet 6 Filed March 13, 1940 we m E .0 my m 70. a v a W June 14, 1949. GOLDBERG 2,472,967

DRILLING MACHINE Filed March 13, 1940 10 Sheets-Sheet 9 I l I l INVENTOR. [/erwzan C dezy May I ATTORNEYS.

June 14, 1949. H. GOLDBERG DRILLING MACHINE l0 Sheets-Sheet 10 Filed March 13, 1940 IN VENTOR.

Patented June 14, 1949 "DRILLING MACHINE .5 Herman Goldberg, Chicago, Ill. Application March '13, 1940; SrialNo. 323,648

.3 5.0laims.

' This invention relates to improvementsindrllling maohines and-the like-andiitspurposesisito provide an improvedmachine in whichithemovements of the'drillnr'other toolyiman axial direction, toward and from and-ithrough thelwork are eifected by fluid pressure.

engage and penetrate ithe -WOlki=- by mnyielding pressures of too greatmagnitude, giving :rise :to frequent: breakage. :when 2 :the: d-HHSL first; engage the work and alsoawhen theyfirstbreaklthrough the work pieceupon: oompletion:-- of-:theldrilling operations. "When the. drillingmfi aih'ole :through a piece of work is substantially completedcandzthe tip of :the: drill-is. about to break "through, the drill is momentarily supportedsby. fragmentszbf -metal engaging: then flutes; at :its. sides; and if. the drill .breaks throughv too rapidlyland-under too. great a-pressure, thereis. atendency forrfrequent breakage.

The principal object of the :presentiinventionis t .;provide. an improvedmdrilling machine'or the like :in 2 which the movementsofotheldrillv toward "the worklare' effected; by improved fluidrpressure .mechanism; capable of :being precisely; adjusted so .that the drill engagesv and penetrates lthe-work with a yielding; pressure which permits the axial -movementof the drill to be arrested withoutdamage in the eventv that any=unusual resistance is encountered.

- Another object of the-inventionrisitq providean improved drilling \machine comprising .-.fluid -pres sure mechanism forrmoving the drill toward l and through the work and-includingimeans for. automatically retarding the movement; ot-.-the:d-rill1 as it is about to *break throughtthet-work-so that damage to the drill is prevented.

"A 'furtherobject of the invention iseto provide an: improved" drilling :machine'a comprising fluid pressure mechanism 'for movin -theldrilla axially toward and from gthe' work and ion automatically stopping Ithe 'movementof ther drill -when the drilling of the hole is completed.

Another object of the -.invention. is to provide a drilling machine having fluidpressuremechanism for efiecting axial 'movementxof the :drill and ineluding: a: dash -potf for automatically: retarding the axial movementofiithe drillaatethe end ofoits stroke.

l the dash-potmechanism in Other objectsrelate-to various-features or construction" and arrangement which w'illappear more fully hereinafter.

The'n'ature of the* invention will-he understood from the following specification taken-With-the accompanying drawings in whichone "embodiment of the inventionis illustrated. in the drawings,

Figure 1* shows a -froht elevation ofa? drilling a machine embodying the -'improvements 'of l the present invention;

Fig. 2 shows aside elevation of the: machine i=1- lustrated in Fig. with a part of the casing brokenaway;

i Fig. 3 a somewhat diagramm'atio view; with parts showing in section? illustrating the fluid pressure connections to difierent' parts oi-the apparatus for causing forward and reversestr'okes 'of the I drill and 'for ope-rating the pump by which a cooling fluid is. circulated to the-point where the drillingoperation -ita-kes place;

i Figs-4 shows an enlarged'vertical section-taken on the line 4-4 of Fig 2;

- Fig; 5 shows a vertical section taken. on-the line 5'5 of Fig;- 4;

Fig; 6 shows aghorizontal line 66: of. Fig. 5;

Lv Fig. Tis a vertical section taken'omtheilin 1 -1 "of Fig. 6;

Fig. 8 showsan: enlarged zfrontelevation' of the -piston bl0ck andwalve'block of thewmachine with .the: cylinders. which actuate the. pressure: platen .iby which the? drillvis-carriedg. and the. cylinder: of the. dash-'pot:mechahism';t:shown in section;

- Fig. 9=shows a-horizontal section .takenconthe line'9 -9 ofiFig: 8;

i-Fig. -10 shows. a horizontal section taken onthe linel0'l0 of: Fig.15;

Fig. 11 shows a sidelielevatiom'bf the forward :portion-ofthenylinderblock andthe drill actuating mechanism with a part 'of lthe" valve: block-of :the dash pot mechanism. broken away;

Fig. '12'shows avertical section" taken'on the dine: 2 I 2- of Fig. 8 illustratingfthe plunger *of 'its lower position -.Wherein 'it retards the movement 0f the i drill at the end ofits downward stroke;

Figs 13- isa verticalsection similar-*to' th'at of Fig. 12 showing the lower part er the da sh-pot mechanismwhen the'plunger has been elevated;

:Fig. 14 shows a horizontal section takenon the line *I 4'l 4" of Fig. 13;

Fig.15-Ishows a vertical section through-the cylinder of the foot operated valve' by -which the drilling. strokes ofithema'chine' are =controlled by sedtiomtaken on'i the 3 the foot of the operator, this view showing the plunger of the valve in its upper position.

Fig. 16 is a sectional View similar to that of Fig. showing the plunger of the valve depressed by the foot pedal;

Fig. 17 shows a partial side elevation and partial vertical section through a rotary pump by which cooling fluid is pumped to the place where the drill is operating;

Fig. 18. shows an enlarged side elevation of one of the pressure regulators andits connections for regulating the pressure of the fluid supplied to the cylinders by which the drill is moved;

Fig, 19 shows an enlarged front elevation of the pressure regulators and pressure gauges ill I the driving connections between the motor 4%} and the drill 35 which are best illustrated in Figs. 4 and 5. As there shown, the motor it is carlustrated in Fig. 18; Fig. 20 shows a detail sectional view through one of the pressure regulatorsf and" Fig. 21 shows a top plan view of thestructure illustrated in Fig. 19.

a hollow casing 25 having; an; enlarged base portion 25 adapted to be secured upon a floor or other support. The front of the casing 25 is provided with a vertical slotted guideway 25 on .which there is mounted. a vertically adjustable bracket 26 formed integrally with a work table 21 on which the piece of work. -28 to bedrilled is adapted to be held or secured when the drilling ;;.K

operation is being performed.- The bracket '26 and the table ,2'1 are adaptedtto be adjusted vertically by a worm and,-worm wheelpperated by a crank 29 and when the table 21 has reached the desired level, it is secured in adjusted position 1:.

31 which is secured to the face of the upper part 25 of the housing 25., The piston block 3? has mounted on the frontthereofa valve block 38 which carries the dashpot mechanism by which .thedownward stroke ofthe drill is retarded and arrested. The upper end ofthe, cylinder block Elis closed by a pulley casing39 which is secured to and also enclosesthaupper end of the housing 25... Withinthe; upper portion. 25 of the housing 25 there is mounted an electric motor 53 which is connected to. effect the ,rotation of the drill 35 .through. mechanism hereinafter described. The electricconnections M for actuating the motor-'40 are brought in through the rear wall of the casing 25.and.these.connections may also serve to supply current .to another electric motor 42 which drives a pump 43 mounted in the base portion 25 of the casing and adapted to pump oil or the like to the point where the drill 35 engages the Work 28.

As shown in Fig. 3, a supply conduit 3% leads from an air compressor or other source of compressed fluid to a supply casing 45 from which a pipe 46 leads through a pressure regulator 4'! to a gauge lii adapted to indicate the pressure of the fluid on the discharge side of theregulator il. From the pressure gauge 48 a supply pipe 49 leads downwardly to a foot'operated valve 50 adapted to be actuated by the foot pedal 51. From the foot operated valve 58 a supply pipe 52 leads upwardly through the housing-25 to the valve lock 38 by which the cylinder mechanism for effecting the downward movement of the drill 35 is controlled. The casing 45 also supplies compressed fiuid through a pipe 53 to another pressure regulator M which in turn is connected to The invention is illustrated inthe drawings as being embodied in a drilling gnachine. comprising be to a nozzle Si by which oil or the like is discharged up'on the work 28 beneath the drill. The foregoing description has been intended to give a general view of the principal parts of the machine before describing the details of any of these parts and reference will now be had to ried by a plate 53 which rests upon flanges 25 l formed on the upper end of the housing 25 and which is clamped in position on those flanges by-studs '59 engaged-by lock-nuts iii By this arrangement, the motor may be shifted on the housing 25 inorder to tighten the belt (H which extends between a pulley 62, fixedupon the shaft id of the motor, and another pulley 83 which is fixed upon a vertical pulley shaft Ed. The pulleys 6i and 63 are constructed in the form of truncated cones, being provided with a series of oppositely disposed groovesBZ and 63 which ar e.of

different diameters, the larger grooves of each pulley being disposed opposite to the smaller grooves of the other pulley so that by shifting the belt 61 to different pairs of grooves the speed of the pulley shaft 64 may bevaried to cause a corresponding variation in the speed of the, drill 35. The shifting of the belt may be effected by moving the motor All on its supporting flanges 29*, and then restoring the motor to the proper position.

' As shown in Fig. 4, the pulley B3 is secured by a key 51 upon the upper end of the pulley shaft til and it is arranged to" seat upon an annular shoulder fit formed on an enlargement of the shaft. Y The upper end of the shaft is threaded for engagement by a nut 68 which is adapted; to seat in a recess formed in the upper end of the pulley B3 and which holds the pulley against endwise displacement on the shaft. The cylinder block 5? is provided at its upper end with a is closed by a cover plate 1o secured to the upper end of the cylinder block. Thelower end of the pulley shaft 64 is threaded for engagement by a pair of lock nuts H which hold the pulley shaft against vertical displacement in its bearings. The cylinder block is secured to the face of the housing 255 by studs 13, shown in Fig. 9, which pass through apertures in the cylinder block and engage threaded holes in the bosses 25 which are formed on the upper end of the housing. The cylinder block is held against lateral displacement by a vertical key M engaging keyways in the cylinder block and in the housing and held against vertical displacement by a screw 15. In this manner, the cylinder block and the pulley shaft 54 are mounted in fixed positions and the shaft is adapted to be operated continuously, when the motor MI is in operation, for driving a vertically adjustable drill spindle 11 which has a splined engagement with the lower end of the shaft as shown at 65' in Fig. 4.

The drill spindle 11 extends downwardly through the'central tubular bore 'of a pressure platen 80 which is adapted, to be actuated for moving the drill spindle 'I'I longitudinally and thereby moving the drill 35 toward and from the work. The pressure platen comprises an upwardly extending sleeve 80 adapted to slide vertically in a bushing 8| mounted in the central bore 31 of the cylinder block, and the drill spindle'Tlis :journaled in a ball bearing unit 82 secured in the intermediate part of the sleeve portion 80 of the pressureplaten. This ball bearing unit 82 seats against a shoulder at the end of the lower enlarged portion 11*- of the drill spindle-and is held in position against that shoulder by a nut 83 engaging a threaded portion 11 of the spindle IT. The pressure platen 80 is also provided with a downwardly extending sleeve 80 and the lower part. of the drill spindle I1 is journaled in another ball bearing unit 84 which is mounted in the lower end of the sleeve 80".

The, outer ring of this ball bearing unit seats against an annular inwardly extending flange 80 formed on thesurrounding sleeve and it is held in position against that flange by a nut 85 engaging the internal threads on the lower end of the sleeve as, illustrated in Fig. 4. An annular shoulder 114 is formed on the lower end of the spindle 'I'I within the nut 85 and the inner ring of the ball bearing is clamped against this shoulder. by nuts 86 engaging the threaded portion 11 of the drill spindle. A standard drill chuck 80 is mountedupon the tapered lower end of the drill spindle for detachably securing in place, in axial alignment with the spindle, the previously described drill 35. A nut 89 is mounted on the threaded portion IT of the spindle and may-be rotated to force the chuck oil of the spindle-when desired.

The pressure platen 80 is provided with two similar oppositely extending arms which are apertured for engagement by the reduced extremities 90 of piston rods 90, nuts 9| being secured to the threaded extremities of the parts 90 of the piston rods for securing the rods in fixed relation to the pressure platen. The piston rods 90 slidably engage cylinder heads 92 which are mounted in the lower ends of the cylinders 37 which are formed in the cylinder block 31 at opposite sides of the central bore 31 At their upper ends, the piston rods 90 are secured to pistons 93 which have sliding fits within the cylinders 31. The upper ends of the cylinders 31 are closed by detachable threaded plugs 94 and these plugs are accessible through the chambers 31 which are formed in the upper end of the cylinder block and through which access may be had to the plugs 94 when the pulley casing 39 is removed. The pistons 93 are normally moved to their upper positions, shown in Fig. 4, by the action of compressed fluid admitted to the lower ends of the cylinders from the pipe 54, previously described, which, as shown in Fig. 10, is connected to branch pipes 54 connected by threaded nipples 54 with passages 3'I extending through the cylinder block 31 and communicating with the lower ends of the cylinders 31, as illustrated in Fig. 4. The upward movement of the pressure platen 80 is limited by the engagement of the annular shoulder 80 of the pressure platen with the lower end of the cylinder block and when the pressure platen is in this upper position the pistons 93 are spaced slightly below the plugs 94 which are mounted in the upper ends of the cylinders 31.

In'order to move the pistons 93 downwardly sure is adapted to be admitted at intervals to the space between the'pistons 93 and the plugs 94 at the upper ends of the cylinders and this fluid' of a higher pressure is supplied through the previously described pipe 52, the flow through which is controlled by the foot operated pedal 50. The: pipe'52 is connected to a coupling-member 95,

shown particularly in Fig. 6, which threadedly engages an opening 38 formed in the valve block 38, previously referred to, which is secured by means of screws'96 upon the front face of the; cylinder block '31, as shown in Fig. 7. The inner end of the opening 38 communicates with a passage 38*, shown in Fig. 6, which leads to a transverse passage 3'! formed in the 31 lead to the upper ends of the cylinders 3'! so that when compressed fluid is admitted to theshaft 64 while maintaining its splined connection therewith.

The downward movement of the pistons 93 and the corresponding downward movement of the drill 35, brought about by the admission of compressed fluid to the upper ends of the cylinders 31, are controlled by the valve 50 which is operated by the foot pedal 5|, shown particularly in Figs. 3, l5 and 16. The foot operated valve comprises a base I00 adapted to be secured to the floor or other support adjacent the base portion 25 of the housing 25. This base plate has mounted thereon an upwardly extending pedestal I 0| upon which the foot pedal 5| is pivoted to depending ears 5| by a pivot pin I03. At the other end ofthe base plate I00, there is mounted an upwardly extending valve block I04 having formed therein a vertically extending cylindrical bore I 04% in which is mounted a cylindrical valve member I05. This valve member is provided with a rounded upper extremity on which the free end of the footpedal 5| rests so that when pressure is exerted on the pedal the valve member is forced downwardly against the compression of a coil spring I06 which is seated in a recess in the lower end of the valve member and which has its lower end resting in a depression formed in a removable disk I01 detachably secured in the lower end of the enlarged chamber I04 which communicates with the bore I04 and which receives the annular flange I05 formed on the lower end of the valve member. This spring I06 thus normally forces the valve member to its uppermost position, shown in Fig. 15, and thus causes the foot pedal 5| normally to occupy its uppermost position.

The valve block I04 is provided on opposite sides with two ofiset ports I04 and I04 the first of which communicates through a coupling member I08 with the supply conduit 49 previously described, while the other port I04 communicates through a coupling member I09 with the conduit 52 leading to the valve block 38. When the valve member I05 is forced downwardly by depressing the pedal 5|, the two 'ports I 04" and I04 are connected through the-chamber formed face of the cylinder block 3! behind the block 38. This passage communicates with branch passages 3'! which by the wide annular groove I05 which is formed. in the valve member I05. Thus, as longlasthe.v foot pedal 5| is depressed, there is a continuing supply of compressed fluid tothe valve block 38 and to the cylinders 31 for causing a downward movement of the pressure platen 80 and of the rotating drill 35. The valve block I04 of the foot operated valve is provided on its rear side with a port 04 leading to the atmosphere from the bore I04 and when the valve plunger I is in its uppermost position, shown in Fig. 15, the pipe 52 is adapted to communicate with this port through the annular groove I05 of the. valve plunger so that air in the cylinders 31 is then permitted to exhaust to the atmosphere during the return upward strokes of the pistons 93 which are effected by the constant fluid pressure acting upon the undersides of those pistons and admitted to the lower ends of the cylinders 31 from the pipe 54. i

The conduit 49 which supplies compressed fluid to the foot operated valve 50 is in turn supplied with compressed fluid through the pressure gauge 48 from the pressure regulator 41 connected to the supply casing 45 by the pipe 46. This pressure regulator is illustrated particularly in Figs. 13, 19 and 20, and it is similar in construction to the other pressure regulator 41 which is connected in the pipe 54 leading to the lower ends of the cylinders. These pressure regulators are mounted for convenience adjacent the upper part 25 of the casing 25 and each pressure regulator comprises two casing elements H2 and H3, which have-threaded engagement with each other and which are adapted to clamp between them a resilient diaphragm I I4. A plate I I5 is mounted on one side of the diaphragm and a coil spring H6 is mounted between this plate and a collar I I1 which is mounted on one end of an adjusting screw IIB. This adjusting screw threadedly engages the end of the casing I 13 and has a handle H8 which permits the screw to be turned to regulate the compression of the spring I16 and a look nut I I0 may be used to secure the screw I I8 in adjusted position. In this manner, itis possible to regulate the initial compression of the spring IIB which must be overcome by the outward movement of the diaphragm II4 under the influence of the compressed air or other fluid which is admitted to the pressure regulator through the pipe 46 (or 53). A disk I20 is secured to the face of the diaphragm H4 and this disk is connected. by a valve stem' I2I with a valve member I22 which is adapted to control the admission of compressed fluid through the ports II2 into the chamber 3 adjacent the diaphragm. The valve member I22 carries a block I23 which is engaged at its opposite end by a coil spring 124 capable of being adjusted by a plug I25 having a threaded engagement with an aperture formed in the end of the'casing II2. By adjusting this plug, the compression of the spring I24 may be varied to regulate the pressure with which it normally causes the valve member 522 to engage its seat around the ports Il2 The compressed air or other fluid which issupplied through the pipe 43 (or 53) is admitted through a port H2 to the chamber IIZ which is on the inlet side of the valve member I22. The back pressure of the fluid in the pipe 49101 54) communicates with the chamber II3 adjacent the diaphragm through a port II2 When this back pressure, which is the pressure at which the compressed fluid is supplied to the foot operated valve 50, falls as a result of the flownof fluid'to 8 the valve block 38, the diaphragm H4 is moved byithe spring H6 with the result that the valve I22 opens the ports IIZ thereby admitting additional compressed fluid from the supply pipe 46.. to the chamber II3 adjacent the diaphragm.

The diaphragm is then moved against the compressionof the spring II6, thereby causing the valve I22 to be moved again to its closed position.' This additional supply of compressed fluid which is thus admitted to the chamber H3 passes through the pressure gauge 48 and the pipe 49 to the foot operated valve 50. By Suitably adjustingthespring's flfi and I24 of the pressure regulator, the frequency and extent of opening of the ports I'I 2 by the valve122 may be regulated-in order to maintain any desired pressure of the-fluid supplied to the foot operated valve 50 and to-the lower ends of the cylinders 31.- These' pressures may be conveniently indicated :by the pressure gauges 40 and 48 'located immediately above the pressure-regulators, as shown in Figs. 18 and 19. The pressure regulators and the gauges may preferably be mounted so that their front faces and operating handles, respectively, are revealed 'or accessible through openings in the front wall of the casing 25. The pressure regulator 41 is always adjusted so that the pressure tending to return the pistons 93 to their upper positions willalways be less than the pressure which is admitted to the upper ends of the cylinders 31 for causing downward movements of these pistons against the pressure act ing on the lower faces thereof. As the pistons 93 move downwardly, the shin the lowerends of the cylinders 31 is further compressed, the

amount of the compression increasing in degree as the end of the working stroke is approached, thus retarding the movement of the pistons and cushioning their movement at and near the end of the; stroke. This further compression takes place even though there may be some leakage where the piston rods pass through the heads 92' but the initial pressures are always so adjusted that there is never a balancing of the pressures on opposite sides of the pistons which are'thus always able to complete their working strokes. y j' When the operator depresses the plunger of the foot operated valve 50 to cause'-compressed fluid to flow to the upper ends of the cylinders 31 through the pipe 52 and its connecting passages, the downward movement of the pistons 93 and of the pressure platen 80 continues until the operator releases his pressure upon the foot pedal 5I or until the downward movement of the pressure platen is automatically retarded and eventually arrested by the dashpot mechanism heretofore referred to. This dashpot mechanism which is particularly illustrated in Figs. 5 8, 9, 10, 11, l2, l3 and 14, is carried by thevalve block 38-; previously referred to, comprisesa cylinder 38 formed in the valve block and having mounted in the lower part thereof a cylindrical cage-like member I30 comprising a cylindrical bottom portion I30 connected by opposite upwardly extending webs I30", shown in Fig. '14, with a transverse portion I30 from which a sleeve I 30 extends upwardly. The sleeve portion and the transverse part I30 are provided with a cylindrical bore in which there ismounted a cylindrical dashpot-plunger I3I. The member I3I extends above the upper end'of the sleeve I30 and is' provided at its upper end with an outwardly-extendingflange I3 L Arcoil spring 7 I32ismounted' around the sleeve I30 and-around the upper end of the-plunger I3I and it serves normally to maintain the plungerin its upper- -most position, shown in Fig. 13, the upward movement of the plunger being limited by a transverse pin I33 mounted in the lower end thereof and adapted to engage the underside of the transverse portion I30. The cylinder 38 is adapted to be partially filled with abody of oil I34 or other substantially incompressible fluid and the bottom portion I30 of the member I30 is provided with a well I30 the outer annular wall I30 of which is enlarged toward its upper end to'a slight extent. When the dashpot plunger I 3| moves downwardly from the positionshown in Fig. 13 to the position shown in Fig. 12, it is adapted to enter the well I30 and thus can trap a part of the oil which is contained therein. Apart of the oil is adapted to pass out around the lower end of the plunger but, as the plunger continues'its downward movement, the fit between the-plunger and the annular wall I30 becomes increasingly tighter and the plunger I3! is eventually brought to rest.

In order to make use of the above described action of the dashpot plunger I 3| for retarding the downward movement of the pressure platen 80 and eventually arresting that movement, connections are provided for causing theplunger I3I to be moved downwardly by the pressure platen as it nears the predetermined lower limit of its stroke. For this purpose, there is provided a vertically slidable actuating rod I35 having an enlarged cylindrical upper portion I35 shown in Fig. 7, which is mounted to slide in a cylindrical bore 38 formed in the valve block 38. The pp r end of the enlarged"portion I35 has a transverse arm I35", shown particularly in Fig. 9, which extends over the upper end of'a cupshaped cap member I36 which ismounted in inverted position over the upper end of the dashpot'plunger I3I, as shown-in Fig. 12. When a downward pull is exerted uponthe rod I 35, the dashpot plunger I3I is forced downwardly against the-compression of the spring I32 to cause the lower end of the plunger toentrap the oil in the well I 30% When the rod I35 is moved upwardly, the plunger I3I is permitted to return to its normal upperposition, shown in Fig. 12, by the action of the sprin I32.

The rod I35 slidably engages an aperture in a sleeve 80 which is carried by a flange 80 projecting outwardly from the pressure platen.80, as shown particularly in Fig. 5. A collar I 31 is secured by a set screw I38 on the rod I35 in such a position that when the pressure platen reaches its uppermost position the sleeve 80' will engage the collar I31 and thus restore the rod I35 to its uppermost position independently of the action of the coil spring I32 in the dashpot cylinder. The lower part of the rod I35 is threaded as shown at I 35 and this threaded portion is en gaged by a pair of nuts I39 which may be secured in adjusted position thereon so that as the rotating drill 35 reaches a position where it is about to emerge from the hole being drilled through the work, the sleeve 80 will engage the uppermost nut I39 and thus move the rod I35 downwardly so that the dashpot plunger I3I will trap a part of the oil in the well I30 at the bottom of the dashpot cylinder and thus slow up the movement of the rotating drill in the finalstage of its downward movement until, eventually, the drill will be brought to rest when the hole is com pletely formed. The operator, observing this retardation of the movement of the drill, will then ing a cylinder formed therein, a pistonimo n-t'ed in said cylinder and-connected to s'aidE-p said cylinder to move "said pressure" plate said tool along the axis of said tool toward-the;

51 0 release his "pressure upon the foot pedal 5I,so'- that theair acting upon the upper sides of the pistons 93 will be permitted to exhaust through the foot operated valve 50, as previously described, and the pressure acting upon the undersides of the pistons 93 will then'function to'return the pistons, the pressure platen and the. drill 35 to their uppermost positions. The same operation may then be repeatedany number of timesupon different parts of the same piece of work". or upon different pieces ofwork byagain depressing the foot pedal 5| and causing repeateddownward movements of the rotating drill 35.

In order to facilitate the drilling 'of h'oles' by the drill 35 without injury thereto, a quantity of cutting oil is preferably applied to the surface of the work 28 at the point where-the drilling operation occurs through the nozzle 5'! hereto? fore referred to. The construction of the motor operated pump 43, by which this cutting oilfc'irculation is effected, is shown in Figi S17 where it is illustrated as'comprisinga tubular casing -I4.0 mounted in the well in the bottomof the pump casing 25. This casing is enlarged'atits lower end, as shown at I40, for engagement by 'a face plate I'4I which is secured thereto by screws I42;

At its upper end the casing I40 is enlarged as shown-at I40 to receive the lower end of the case ing of the motor 42' and'tofor-m a connection by means of an elbow I43 with the previously described pipe 55 by which the oil isc'onveyedto the discharge nozzle. Mounted withinand spaced inwardly from-the upright tubular portionI40 of the pump casing there is :anfelong'ated "sleeve I44 'having located therein an impeller shait' 'l4 5 which is driven by the shaft of the'motor 42 The'lower end of the sleeve I44 'is spaced, wardly from the enlarged portion I40? of pump casing by a perforated bracket or web which carries on its underside a horizontal I41 provided with a depending annularf fi ang e I41 within which there is mounted the rotat e impeller I48 secured upon. the lower end o f l shaft I45. The face plateflltl I is spaced upwar from the bottom of the Well in the housing zany the feetiliza' which a ev formed thereon andwhei the impeller I48 is rotated, [oil is pt toh' drawninto the portsjI4l This oil vis" 'direcizlji. outwardly by the vanes of'the impeller andjdis charged upwardly around the outer dag er the disk I4! and thence upwardly through the openings of the bracket I46 and between the casing I40 and the sleeve I44 to the upper enlarged portion I40 of the pump casing where it flows out wardly through the connecting member I43 -h work table 2'! of the machine is constructed-wit a drain channel around its outer edgeso that-the 1' oil discharged by the the nozzle 51 may be "directed. back to the well in the bottom'of;the:- housing.

Although one form of the inventionihas be shown and described bywayofillustratio will be understood that it may beconstructd n. various other embodiments coming within the,

scope of the appended'claimsQ I claim: 1.,The combination in a machine of the cl described, of a cylinder block, a pressure,"plat slidably mounted in said block, a rotatable" carried by said pressur'e'platen, said bld platen, means for admitting compressed" work, dashpot mechanism carried by said cylinder block, an actuating member associated with said dashpot mechanism, and means carried by said pressure platen for operating said actuating member to cause said dashpot mechanism to retard and then arrest the movement of said pressure platen when said tool reaches the end of its stroke.

2. The combination in a machine of the class described,.of a cylinder. block, a pressure platen slidably mounted in said block, a rotatable tool carried by said pressure platen, said block havling a cylinder formed therein, a piston mounted in said cylinder and connected to said pressure fplaten, means for admitting compressed air to said cylinder to move said pressure platen and said tool along the axis of said tool toward the work, dashpot mechanism carried by said cylinder block, an actuating member associated with said dashpot mechanism, means carried by said pressure platen for operating said actuating member to cause said dashpot mechanism to retard and then arrest the movement of said pressure platen when. said tool reaches a predetermined position, means carried by said actuating member for co-operating with said last named means to restore said dashpot mechanism to its initial position upon movement of said pressure platen away from the work, and means for moving said pressure --pl aten away from the work.

3. The combination in a machine of the class described, of .ablock having a cylinder formed therein, a piston mounted in said cylinder, a pressure platen slidably mounted in said block and connected. to said piston, a rotatable tool carried by said pressure platen, means for rotating said tool in all positions of said pressure platen with respect to said block, a work holder, means for admitting compressed fluid to said cylinder to cause-said pressure platen to assume normallya position withdrawn from said work, means foradmitting compressed fluid to said cylinder to-cause saidpressure .platen and said tooito move along .the axis of said tool toward said work holder, a valve block carried by said cylinder block and having a dashpot cylinder formed therein, adashpot plunger mounted in said last named cylinder, a rod slidably mounted in said valve block and having a part adapted to actuate said plunger, an adjustable stop mounted on said rod, and means movable with said pressure platen for engaging said stop member to cause the actuation of said plunger by said rod.

4. The combination in a machine of the class described, of a rotatable tool, means for rotating said tool, means for moving said tool axially toward and through the work during its rotation, a block mounted adjacent the path of movement of said tool and having a downwardly tapered recessjherein adapted to contain a quantity of liquid, a plunger slidably mounted in said block and having a lower end adapted to fit said tapered recess after it has been partially inserted therein, means tending normally to force said plunger upwardly, and actuating means operatively connected with said plunger for moving it downwardly to engage said recess after a predetermined axial movement of said tool into the work.

5. The combination in a machine of the class describedmf a rotatable tool, means for rotating said tool, means for moving said tool axially, and means actuated by said axial movement of said tool for gradually trapping a quantity of liquid while permitting a part of said liquid to escape through a passage of progressively decreasing area after said tool reaches a predetermined position, thereby progressively retarding and then arresting said movement of said tool.

HERMAN GOLDBERG.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 706,688 Reynders et a1. Aug. 12, 1902 1,069,995 Anderson Aug. 12, 1913 1,216,689 Hey Feb. 20, 1917 1,217,469 Loguin Feb. 27, 1917 1,688,428 Morgan Oct. 23, 1928 1,812,533 Hunt June 30, 1931 1,911,138 Clute et al May 23, 1933 1,942,414 Dumser et a1 Jan. 9, 1934 1,997,490 Sawyer Oct. 16, 1934 1,998,873 Kingsbury Apr. 23, 1935 2,079,640 Vickers et al May 11, 1937 2,114,389 Kingsbury Apr. 19, 1938 2,133,170 Johnson Oct. 11, 1938