US2767688A - Hydraulically actuated multiple spindle paper drill - Google Patents

Description

0t.23,'1195e- -w. R. SPILLER Em. 2,767,688

'y HYDRAULICALLY ACTUATED MULTIPLE SPINDLE PAPER DRILL Original Filed Dec. 26, 1946 '7 Sheets-scheet .1

Oct. 2.3, 1956 w. R. sPlLLER ETAL HYDRAULICALLY ACTUATED MULTIPLE SPINDLE PAPER DRILL Original Filed DBC. 26, 1946 7 Sheets-Sheet 5 Oct'. 23, 1956 w. R. SPILLER ET AL 2,767,688 HYDRAULICALLY ACTUATED MULTLPLE' SPINDLE PAPER DRILL original Filled Dec. 2e, 1946 gmc/MW -/WQ 330 @wijd/@Www @Mouw/1415 .8 8 6, .7 u 2.1 Dn D. R E D.. .A P E. L D N I D.. S m P I m D E M W. om um L M6, C2 Il We AB RD .wm H1 .l F fl a n .l du .l r 0.

Oct.' z3, 1956 w. R. sPiLLER ETAL f? YSheeis-Sheet 5 177' TOR/VE YS Oct. 23, 1956 w.|R.'sP1LLER ET AL 2,767,688

HYDRAULICALLYQCTUATED MULTIPLE SPINDLE PAPERVDRILL' Original Filed Dec. 26, 1946 '7 Sheets-Sheet 6 O 192l i 7 Oct. 23; 1956 W. R. SPILLER ETAL HYDRAULICALLY ACTUATED MULTIPLE SPINDLE PAPER DRILL Original Filed Deo. 26, 1946 7 Sheets-Sheet '7 rl nilllll,

MM M United States Patent HY DRAULICALLY ACTUATED MULTIPLE SPINDLE PAPER DRILL Original application December 26, 1946, Serial No. 718,380, now Patent No. 2,637,396, dated May 5, 19513. Divided and this application June 30, 1952, Serial No. 296,281

9 Claims. (Cl. 121-459 This invention relates to power drills and more particularly to multiple spindle drills for drilling paper and the like. This application is a division of our copending application Serial No. 718,380, iled December 26, 1946, and nowvPatent No. 2,637,396.

It is the principal object of the invention to provide a multiple spindle drill which is simple and economical in construction, safe and reliable in operation, which is rapid in its action, and the operatori of which is at all tmes under the ready control of the operator.

It is a further object to provide a paper drill operating under hydraulic power with a fast, smooth, uniform and readily controllable operation at all times.

It is also an object to provide a multiple spindle drill in which the bottom stop position of the group of drill heads is adjustable simultaneously.

It is likewise an object to provide such a drill in which an excessive load occurring at any point in the working stroke will cause the termination of such stroke and the return of the machine to its inoperative position before any damage is caused thereto.

It is also an object to provide such a multiple spindle drill in which the upper position of the group of drills is likewise adjustable simultaneously.

It is a further object to provide hydraulic mechanism for actuating a device such as a paper drill in which a work member is brought into working position with respect to a work table, in Vwhich the bottom position of the working member is determined by a positive stop in the path of travel of the hydraulic mechanism.

It is a further object to provide a hydraulically actuated drill in which the stroke is adjustable both at the top and the bottom to adapt the drill to different work operations.

It is also an object to provide a drill of this character in which an emergency stop is provided by means of which a working stroke may be interrupted, reversed or allowed to continue to completion, under the control of the operator.

It is a still further object to provide a hydraulic actuating mechanism for such a machine with the hydraulic mechanism being entirely confined within a housing or revervoir so that it forms a separately installed and easily removable power pack for the machine. v

kIt is also an object to provide such a drill in which selected control over the speed of the downward or working stroke may be obtained by manual selection while maintaining a substantially uniform high rate of speed for the return stroke.

It is a further object to provide hydraulic operating mechanism for such a drill which is adequately protected against development of abnormal or potentially damaging pressures.

Other objects and advantages will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings:

2,767,688 Patented Oct. 23, 1956 ice Fig. 1 is a view in perspective of a machine constructed in accordance with the present invention;

Fig. 2 is a view of the machine partially in front elevation, with the front housing and the right hand post guides being broken away, certain parts such as the chip cbllecting mechanism and the drawer being removed to better show the construction;

Fig. 3 is a vertical sectional view from one side substantially on the line 3-3 of Fig. 2;

Fig. 4 is a horizontal sectional view showing the top of the work table in plan;

Fig. 5 is a broken sectional view substantially on the line 5-5 of Fig. 3 showing the path of discharge provided for chips produced on the cutting table;

Fig. 6 is a horizontal sectional view looking down upon the power mechanism with the top cover thereof removed, the section being taken substantially on the line 6-6 of Fig. 2;

Fig. 7 is a diagrammatic view showing the hydraulic circuit and its controls;

Fig. 8 is a view in horizontal section through the speed control valve substantially on the line 8 8 of Fig. 9;

Fig. 9 is a vertical section through the speed control valve substantially on the line 9-9 of Fig. 6;

Fig. 10 is a view in end elevation on an enlarged scale of the adjustable orifice plate incorporated in the speed control valve;

Fig. 11 is an elevational view of the front plate of the .Speed control valve; l

Fig. 12 is a'section through this plate on the line 12-12 of Fig. 11; t

Fig. 13 is an elevational view of the index plate for determining the positioning of the speed control member;

Fig. 14 is a view in vertical section on the line 14-14 of Fig. 6 showing the construction of the hydraulic counterbalancing valve;

Fig. 15 is a vertical sectional view through the power actuating mechanism on the axis of the piston, along the line 15--15 of Fig. 6;

Fig. 16 is a view in vertical section somewhat diagrammatic in character indicating the path of flow of the actuating fluid for the down operation of the piston;

Fig. 17 is a view in broken side elevation from the outside ofthe power pack showing a portion of the mechanical controls for the machine;

Fig. 18 is a vertical sectional view on a plane parallel to that of Fig. 17 but within the housing of the power pack and on line 18-18 of Fig. 6;

Fig. 19 is a view in side elevation of the pressure actuated release mechanism for effecting stoppage of the downward travel of the head and reversal thereof;

Fig. 2O is a detail view of the adjustable stop for determining the bottom limit of travel of the movable rail assembly;

Fig. 21 is an enlarged View of the lower right hand cornerof the mechanism shown in the power pack in Fig. 6;

' Fig. 22 is asomewhat modified vertical sectional view through the Wall ofthe power pack substantially on the line 22-22 of Fig. 17; andl Fig. 23 is a somewhat modified vertical sectional view through the wall of the power pack substantially on the line 23-23 of Fig. 17.

Referring to the drawings which illustrate a preferred embodiment of the machine, and more particularly to Figs. 1 through 4, the machine is shown as comprising a main frame 10 in the form of a hollow shell, which is preferably formed as an integral casting incorporating a front wall 11, a left hand side wall 12, a right hand side wall 13, and a rear wall 14, the latter being open over the greater part of its extent as shown at 15 (Fig. 3). The top 16 is shown as formed integrally, and is arranged the top being suitably ribbed" as sl1'ow11"`at"'18` to afford additional stiiness.

'Ihe `top `forms an iessentially flat rectangular work table 'surface asmshjwn inFig.'y 'table is i formed with a `serifislof apertures jfor adjiistably receiving 2 g'age n19 the position'of'whicii can beset Vvvithreferi ence to "a scaleZti; "Abac'k gage `21`is1 adjustable at right p 'anglesto the front gageand `it`s position may be deterg mined by scales 22,suchgage'mechanism being known in the art. M Inwardly `of the side walls pairs of lower and upper bosses 23 `are provided,` which 'are preferably formed integrally with the main1 fra'r'ne"1th Bothsts of bosses are bored to provide for receiving the guide posts 24,

, 25, andfsuitable lubricant injecting `means 26 are preferably provided'which are' accessible from outside the frame to lubricate the posts in'their reciprocating travel inthe guides. The posts `24, 25 support the rail assembly 30 on their upper ends, the rail extending transversely across the width o f the work table and providing a support for the individual drill heads. The machine Vas illustrated thus embodies a work table with a rail movable relative thereto and supporting the individual drill heads', the structure `illustrated providing a stationary table cooperating with the reciprocating drill heads; it" will be evident however that the tablemay be caused to reciprocatewith respect to relatively fixed drill heads while still maintaining the same essential features of operation and control.

Hydraulic power operating mechanism is provided for causing such relative reciprocating motion,;'this niechanismbeing in the form of a power pack indicated generallyat 35, as comprising a closed integral `casing for receiving the powery operating mechanism `and likewise forming a reservoir for the hydraulic fluid. The casing 35 has a removable cover 36 which is normally secured in fluid-tight relation thereto by means of gasket 37.A In order to support the power pack in proper position within the hollow base of the'machin'e the cover 36 is formed with an opstanding lug 38, and a bar 39 `extends through in'ithe elongated ilanges 41 of: a plurality lof the ribs which are'integral with the under side of 'the work table 16. The bar is thus normally"supported from beneath the work table, but when it is desiredto install or remove the power pack, the bearing 40l is'removed and the power pack can then be moved rearwardontlie bar and thus removed `as a unit.

A drive motor 44 is pivotally mounted upon a platform 45 in the lower rear portion `ofthe base, suitable adjusting means 46 being provided to rock the platform about `its pivot 47v forthe'purpose of maintaining the proper tension in the drive pulley.v The motor is conveniently controlled by start and stop buttons 43,49 mounted on a panel' 43 von` the front face 11 ofthe frame. The shaft'of the motor'carries drive pulley 50 over which there operates V-belt 51 which has driving engagement withthe pulley 52' which supplies` the power to the 'power pack.

The uid actuated piston within the power pack has a shaft 55 which extends downwardly from the lower side of the power pack as shown' in Figs. 2 and 3 where it hasccnnection with a cross head 56 having laterally extending arms which are bored as shown at 57 to receive the posts 24 and 25, respectively. vThe 'opposite arms of the cross head are secured to the posts by means of a series of pins 53 `so `that vertical movement of the` cross head is transmitted directly jto the two posts, and thereby t'o the rail assembly 30 `of the machine.

Rail `assezrnbly and dcrll heads is formed as an integral casting with parallel gibs 59 @standing frasyerselyarcss its facs and servirle` as a l with a forward portion 17 overhanging the front wall 11,l

lug 3S, likewise extending through'a bearing @mounted i Referring now to Figs. 1 and 2, the rail assembly 30 averses 4 support to adjustably receive the individual drill heads indicated' generally at 6th l As shown in Fig. 2 the vertical face of the rail is preferably marked with a series of parallel indications 61 to facilitate the proper assembly and alignment of the drill heads thereon.

In order to drive the drills, a drive motor 68 (Fig. 3) also controlled by start and stop buttons 48, 49 on the front panel of the main frame, Ais mounted upon bar 71 secured in the rear face of the assembly 30, the motor having a'drive belt Vsuch as `V-belt 73 protected by a cover 74 and running over driven pulley 75 which is suitably connected with the drive shaft 78 for the hollow drills 10) as shown in detail in our above patent and in our copending application Serial No. 296,282 tiled of even date herewith and now Patent No. 2,734,577.

Collection and disposal of chips Hollow paper drills of the present type produce a substantial 'quantity of chips, inthe form of paper confetti, the chips being passed upwardly through the hollow interior of the drill. The present machine provides for removing those chips from the drills wherever they may be located along the rail"'assembly, and for discharging thern into a common receiver or 'container from which they may be readily removed from the machine.

Thechip collecting arrangement in the rail assembly is shown in detail in our above patent, and it`delivers the chips into the upper end of the hollow guide post 24. At an intermediate point 'in its length, namely, that portion which is received within the left hand upper boss 23 of the base, the post 24 is `formed with a vertical slot which communicates with a corresponding passage 146 formed within boss`23 and leading into a downwardly extending passage 147 (Fig. 6V) integrally formed in the side wall 12 of the main frame. The vertical extent of the passage 146`in the frame is sutliciently greater than that of slot 145 inl the post 24 to maintain registry thereof throughout the vertical travel of the post so that communication is thus established at all times. The hollow interior of the post is closed by a suitable block 148 immediatelybelow the slot 145 to prevent the dropping of the chips farther through vthe post.

As shown in Fig. 6, the passage 147 is closed by a cover plate 156.!` mounted on the side wall 12 of the machine, thus forming a closed chamber for the travel of the chips therethrough. At the lower` end of this chamber 147, the chips travel into the open end of a blower 153 suitably mounted upon the wall of the frame and having a drive pulley 154 driven by V-belt 155 from a second drive pulley 156 (Fig. `2) on the shaft of motor 44. A suitable belttighten'eiand idlerpulley assembly 157 may be provided as shown in'Fig. 3.

The discharge of the blower leads through forwardly extending tube 160 to a screen box 162 (Figs. 3 Vand 5) located centrally and immediately behind the front wall 11 ofthe main frame. A screen 163, mounted on an angle as shown in Fig. 3 is provided opposite the end of tube 16,0, in order to allow escape of the air discharged by the blower, the screen however preventing passage of the chips therethrough. The lower end of the box 162 is open and is positioned immediately above a chip drawer having a handle 16,6 which issuitably received in a recess in the front ofltheima'chine, being removably securedtherein by latch nieans 167'."l

`In the operation of the machine for producing marginal slits or slots in the paper, chips are also formed, appearing in this case on the top of the work table 1,6 and substantially immediately in the vicinity, or to the rear, ofthe drill heads on which the slitting or slotting attachment knives are secured. In ordcr to providefor the collection of these chips, the work table is provided with a series of openings which extend in aline across the width of the machine as shown in Figs. 4 and 5. The side walls of these openings are tapered as shown at 17,6 and provide for the collection and delivery ofthe chips through fa funnel 177 having a discharge opening 178, directly leading into the receptacle 165. Thus the chips from both 'sources are readily collected, and in the case of the slots 175., the chips fall directly by gravity into the receiving container. In some cases where no such slotting opera- `tions are to be performed, it is preferred to close the opening175 by means of a plate 179 which overliesl the series "of openings and thus forms a smooth uniform work table surface.

Power pack and hydraulic .system Referring now to the operation of the power pack and the control mechanism for controlling the reciprocating movement of the head, the power pack 35 is provided with an extension 185 (Figs. 3 and 18) at the rear thereof in which there is located a lilling cap 186 and a liquid measuring stick 187 ,to provide for maintaining a constant liquid level within the reservoir substantially as indicated at 188.

Referring to Figs. 6 and 15, the liquid pump is shown at 190, being located within the reservoir and below the normal liquid level therein. It has an inlet line 192 which picks up the uid in the reservoir through a strainer 193 located below the normal liquid level but spaced somewhat above the bottom of the reservoir to allow for the collection of impurities in the well 194 from which they may be removed by a removal of drain plug 195. Pump 19,0 is constantly driven when the machine is in operation from the motor 44, belt 51 and drive pulley 52, as previously described.

The pump delivers fluid under pressure through the delivery line 198 to the directional valve generally indicated at 200. This valve may be of suitable construction such as a Vinco four way open center, open port valve and has a central pressure chamber supplied with fluid under pressure which is selectively allowed to flow to one or the other of two pressure iiow lines while exhaust of the fluid is simultaneously provided for from the other such line. The valve stem 201 as shown in Fig. 18 carries a projecting finger 202 which is movable between Down position adjacent stop 203, through a central neutral position in which it is shown in full lines, to a right hand position adjacent stop 204 providing for the Up direction, the stops being adjustable to secure proper operation of the valve.

v The flow line from the directional valve providing for supply of the fluid for the down direction is shown at 206 in Figs. 7, 18 and 19, and is provided with a T-connection 207, from which the line 20S leads to the speed control valve 210 (Figs. 6, and 8-13). The purpose of the speed control valve is to provide a variable and controllable rate of descent of the rail assembly on its downward or working stroke, as desired for handling different types of work, while maintaining a substantially uniform high rate of return speed of travel. In this way the maximum proper downward travel of the drill heads is provided for on the working stroke, but even where that is necessarily slowed down for best operating results, the return travel remains rapid, and thus a stroke of operation is accomplished with a maximum of speed and assurance of proper operating conditions.

Referring to Figs. 8-13 which disclose the construction and operation of the speed control mechanism, the pressure supply line 208 delivers pressure fluid into the body of speed control valve 210 and communicates directly with a passage 212 which is formed in the lower wall of the power pack, as shown in Figs. 9 and 16. Passage 212 communicates with 'an upwardly extending passage 213 which in turn communicates with a laterally extending passage 214 to provide for delivery of the fluid into the upper end of cylinder 216 in which the piston 218 operates', the piston being directly connected to the main piston rod'55.

The speed control valve provides for bleeding a predetermined quantity of fluid from the pressure supply line 208 in 'order to maintain a regulated rate'of flow to the piston at different flow rates, and thus to establish a controlled rate of travell of the piston and correspondingly of the rail assembly. It is also desirable to provide for a uniform rate of travel notwithstanding changes in the load, and consequently a uniform rate of supply of the uid to the cylinder space 216 so that the same rate of travel of the piston is maintained both before and after the work is engaged. f

For this purpose a passage 220 (Fig. 9) formed in the wall of the power pack 211 and in direct communication with passage 212 leads through a throttling orifice 222 into a valve chamber 224 in which the axially movable valve body 225 is located. Spring 226 normally urges the valve body toward the right, while the pressure of the fluid introduced through port 222 engages the face of the valve body and tends to move the same toward the left. When this action takes place, however, a land 227 formed integrally with the body partially closes the port 222 thus restricting the ilow and providing for maintaining a regulated pressure within the valve chamber. The Valve body is ported las shown at 228 to provide for the free flow of the uid into the end chamber 229, this chamber being closed by a selector disk 230 (Fig. l0). l

Selector member 230 is formed with a forwardly projecting stem 231 by means of which it may be rotatably adjusted, and is likewise provided with a series of drilled openings 232, 233, 234 and 235. As indicated in Fig. 19, opening 232 is closed at its inner end but has a side passage 236 leading radially outwardly therefrom (Fig. 8). Each of the remaining ports 233 to 23S inclusive, has no side passage but is formed with a central aperture through its inner or bottom end, these apertures being of progressively varying size with opening 235 being of the smallest size.

The selector disk 230 cooperates with a fixed plate 240 which is secured in position on the face of the value body 210 by means of bolts 241, and this plate is provided with a port 243 (Fig. l2) which leads outwardly through passage 244 providing for discharge of the Huid directly into the reservoir. ln Fig. 9 the selector Valve has been shown in the position in which one of its ports 234 is in alignment with passage 243 thus providing for discharge of the liuid from chamber 229 directly back into the reservoir. In Fig. 8 the port 232 has been shown in alignment with passage 243 of the plate 240, and further in this position it will'be evident that the passage 236 is aligned with an auxiliary passage 246 formed in the valve body 210, which in turn communicates with passage 247 in direct communication with the supply line 208.

In operation, and assuming iirst that the selector disk 230 is in one of the speed control positions with for example its port 234 in alignment with passage 243, the operation is as follows. Fluid under pressure is supplied through conduit 208 into passage 212, passages 213 and 214, and from there into the upper side of the cylinder for a downward stroke of movement. However there is a parallel path of llow for the fluid supplied from the pump, and hence the rate of downward travel of the piston is less than it would be if the full flow were being delivered to the piston. This parallel path of flow comprises the passage 220, port 222, the Valve chamber 229, and through the port 234, and passages 243, 244, to

the reservoir. This parallel passage bleeds away a partl of the iiuid flow and thus provides for control of the downward descent of the piston. The function of the regulating valve 225 is to maintain a uniform pressure in the valve chamber 229 and thus to establish a uniform quantity of fluid passing through the bleed-off passage which it does by maintaining a substantially uniform pressure regardless of which of the ports 233-235 is aligned with the discharge outlet. With the pump continuing to deliver a uniform volume of fluid, and witha constant quantity being bled off, it is clear that the Huid will be supplied to the piston at a constant rate, notwithi standing `variations in the load imposed on the piston as I Pthe result of the drills encountering the work.

In order to vary the rate `of downwardtravel of the g piston, the selector stem 231 is rotated to bring a selected one of the `ports 233 to 235 into alignment with the aperture 243, as will be readily understood.

It is likewise desirable to be `able to stop the rail assembly at the bottom of its travel in order to provide for the accurate setting of the individual drill heads with i reference to the cutting stick on the Work table. This is i accomplished with the present control by adjusting the selector disk 230 to the position where its` port 232 is 1 in alignment with passage 243, under which conditions the passage 236 ;is also in alignment with passages 246,

l 247. It will be evident that in this position a direct discharge path is provided for the fluid from the pressure line 208, through passages 247, 246, ports 236, 232, 243 and 244, leading directly to the reservoir.` `The pressure control valve 225 is` not included in this ow path and it will thus be clear that the full fluid flow is discharged back `to the reservoir; even though the directional valve is setto supply fluid to the piston in the down direction, there will be only a relatively reduced fluid pressure effective `upon the piston, and thus it will merely proceed to its bottom position and remain in such position. This is referred to as the stop bottom position and makes it possible for drills to be accurately adjusted relative to the cutting stick, which is shown at 95 (Fig. 4) and is received within a slot in the top of the work table.

In 1order to provide for adjustment of the selector disk 230 from the face of the machine, its stem 231 is connected by means of pin 250 with an operating tube 251 which in turn connects witha shaft 252 passing through and sealedwith respect to the wall of the power pack (Fig. 6).

At its outer end shaft 252 is similarly coupled with a tube 254 and that in turn is actuated by a shaft 255 which extends through` boss 256 formed on the front wall of the main frame. A hand knob` 257 is secured to the outer end of shaft 255 and is yieldingly urged inwardly by spring 258, the handle carrying a suitable detent on its inner face which is adapted to be seated in one of the several recesses 260 on an index plate 262 as` shown in Fig, 13. The plate is suitably secured to the front wall of the main frame and is provided with fourrecesses similarly numbered 265,?, and located in 90 relation with respect to each other, corresponding to the ports 232 to 235 of the selector` disk 23). Thus by turning the knob 257,'its detent can be seated in any desired one of the recesses 26tl,to thus select one of the settings of the selector disk 23%, `corresponding to three diterent speeds, and the stop bottom position.

In addition as shown in Fig. 13 there is an intermediate recess-26,4 at `an intermediate position between an adjacent pair of recesses 260; When the control knob is adjusted to the position determined by this recess 264, the selector disk 230 isthereby set in such position that none of its ports` aligns with the discharge passage 243 or with passage 246. Hence the bleed path is entirely closed, and thus the full flow of the` fluid is transmitted to the upper side of the piston, and this provides for downward travel of the rail assembly at maximum velocity.

Asthe piston 213 travels downwardly, the fluid on the lower side, thereof is discharged from the lower cylinder space 270 (Fig. 15) and ows through conduit 272which leads through a packingV box 273 bolted in position be' neath theV power pack, the conduit 272 leading into a hydraulic compensating valve 275, shown in section in Fig. 14. This valve has a ball `check 276 which seats against a return flow of fluid from the bottom cylinder 271) toward the valve, as will be evident from the showing of the constructionin Fig. 14. A pressure line 278 leads into the valve 275 from the directional valve 266] (Fig. 18), and it is through thisline thatpressure is deliveredV from the directional valve whenl the latter has been adjusted for upward travel of the piston. The valve 275 is suitably drilled to `provide a chamber 281) with a communicating passage 281 which is normally closed by a slide valve 232 limited by a fixed pin 283 'and suitably guided for axial travel. The valve 282 has a shoulder portion 285 of reduced diameter, and against the upper end of this shoulder there acts a compression spring 286, the spring passing through an aperture in a washer 287 which is seated within a cylindrical passage 283 provided in the body of the valve. The washer 287 is normally retained in its lower position by means of an outer and more powerful spring 239, both springs being retained in place by cap 290. A discharge passage 291 leads directly into the reservoir, and a cross passage 292 leads from the conduit 272 to a pressure chamber 293 located below the valve 282.

The operation of the hydraulic compensating valve is as follows. lt is important to provide for a properly controlled and regulated descent of the rail assembly at all times, including the period when it is merely falling freely and before the drills have engaged the work, aswell as during the drilling ofthe work. 1f there were no provision otherwise, and the rail assembly were actuated to begin a downward stroke, it could fall more rapidly than the rate of delivery of the fluid above its operating piston, and this would be undesirable as providing an excessive rate of travel, and also as involving a shock and subscquent slowing down of its travel when the drill actually encountered the work. It is the purpose of the hydraulic compensating valve therefore to maintain the downward travel of the assembly uniform throughout the operation and particularly during the period before the work has been engaged.

To accomplish this, the fluid from beneath the operating piston 218 flows through the conduit 272 and into the valve 275, its direct passage into chamber 280 being blocked however by the ball check 276. It isthereupon forced to travel through passage 292 and into chamber 293 where it raises the valve 282 against the force of its lighter compression spring 286. As the valve 282rises, it will uncover the port 231 and allow the fluid to flow into chamber 230, through the pressure line 278, and into the directional valve 2% from which it is discharged back into the reservoir through discharge port 295. The pressure of spring 236; acting on valve body 282 thus establishes a relatively light but suflicient hydraulic brake upon the downward travel of the piston to prevent its falling away from the fluid and to require an actual fluid application to drive the piston downwardly and thus the piston will be driven downwardly on its working stroke at a predetermined and uniform rate, as already described.

When the directional valve 200 is moved to the up positionwith the member 202 against stop 2G4,.fh1id under pressure is delivered from the directional valve through conduit 278 and into compensating valve 275. However with the fluid now flowing into the opposite direction, ball` check valve 276 is unseated, and the. uid passes directly through conduit 272 and into the cylinder 270 beneath piston 21S, causing the piston to travel upwardly in the return stroke of movement.

lt is not necessary to provide a variable rate of speed of the piston on its` return stroke, and thus the fullpump discharge is` supplied in the path of ilow just described so that the piston uniformly travels at its maximum rate. during its return stroke. The fluid above piston 218 isy displaced and flows through passages 214, 213, 212, and conduit 208 back to the directional valve 200 from which it is discharged into the reservoir through discharge port` 296.

Should however any obstruction be encountered in the return travel of the rail assembly such as might lead to excessive or damaging loads or` abnormally high pressurel conditions, a pressure relief is provided which will safe-A guard the mechanism. Under such conditions assum-` ing that the upward travel of therail assembly is blocked, the Pressure is, built sa andA is transmitted.; through pas. sage 292 into chamber 293, thereby raising the slide valve 282, the smaller diameter portion 285 passing freely up-k wardly through washer 287. When the lower edge of valve 282 passes port 281, no change takes place because that space is already in communication with charnber 293. As the pressure rises still further, the shoulder formed by the larger diameter portion 282 engages washer 287, and raises it against the action of the inner spring 286 as well as the heavier outer spring 289, sutiiciently to open the escape port 291. rl`he springs are so selected as to maintain a high but not excessive pressure and to release before a dangerous condition could develop.

In addition to providing for individual vertical adjustment of the drill heads, it is desirable to provide for a range of adjustment in the bottom stop position of the rail assembly. This is desirable to provide an extended range of travel of the rail assembly and of the drill heads mounted thereon. The drills are shortened with sharpening in use, and furthermore drills of different diameters are customarily of substantially different initial length, and it is thus desirable to provide for a range of bottom positions of the rail assembly with reference to the work table.

In order to accomplish this adjustment of the bottom stop position, a positive stop member is interposed in the path of the piston 213, this stop having a series of variable positions. The stop is shown in elevation at 300 in Fig. 20 and in operative position beneath the piston in Fig. l5. It is mounted for angular adjustment on shaft 301 and is formed with a series of flats 302 on its outer circumference each of which is at a progressively different distance from the center of the shaft 301 pro- Viding in effect a spiral shape as shown.

The stop is rotated by means of the shaft 381 which extends through the seal cap 273 secured on the bottom side of the power pack, and through a plate 305 secured in position on the front of the power pack. A disk 386 is secured to shaft 391 by means of pin 307 and has an aperture therein through which there extends a pin 388 carried by an arm 339 which in turn is secured to an actuating tube 318 (Fig. i). The tube 310 telescopes freely over the projecting end of the shaft 391 and the pin 308 extends through the disk 3% and is normally engaged within one of a series of apertures 311 (Fig. 2) formed in the index plate 36S, the tube being normally urged in this direction by means of spring 312. A hand Wheel 313 is mounted in the front wall of the main frame and in position to both pull the tube 310 outwardly to free the pin 308 from the aperture in the index plate, and to provide for rotation thereof with the corresponding rotation of shaft 3431 by means of disk 306 which remains engaged over pin 308.

In operation, it will be evident that the hand wheel 313 can be drawn outwardly against spring 312 and rotated to cause corresponding rotation of tube 310 and of the disk 306, and shaft 301, to reposition the stop member 300 with any of its desired stop faces 302 in position to engage the bottom side of the piston. Upon release of the handle it returns to its normal postion where the pin 308 enters the corresponding one of the apertures in the locking plate 365 and the stop is thus retained in the adjusted position. As a specific example, and assuming a total vertical adjustment in the drill heads themselves of inch, the bottom stop 380 will provide for an adjustment in the bottom stop position of the entire rail assembly of about inch, in a suiciently large number of steps or increments as shown to provide for accurate selection of a desired bottom stop position.

M echam'cal controls In accordance with the present invention, controls are provided for the operation of the machine which make it possible to trip the machine mechanically to begin the operation, the machine then continuing through to the completion of that operation with a downward stroke to the bottom position followed by a return stroke to its 10 original top position without further' manipulation on the part of the operator. This is what may be considered as a single cycle or individual operation requiring a sep-` arate tripping movement from the operator for each indi vidual cycle.

It is also desirable to be able to operate the machine so that having been once tripped by the operator it will perform in a continuous manner, with one cycle following immediately after another.

It is further desired to provide for an emergency stopping of the machine and for this purpose an auxiuiary' manual control is provided by means of which the machine may be stopped at any position in its downward travel, as long as the control remains in one position, andi if the control is then restored to its initial position, the stroke will proceed onward toward completion in the normal manner. If however the emergency control is actuated further, the stroke will not be completed but the rail assembly will return from whatever position it occupied when stopped toward its up or neutral position without having completed that stroke.

It is likewise desired to provide a control for limiting the top position of the rail assembly in order to shorten the stroke where for example the work is of small thickness, so that the length of travel required to complete a stroke is not more than is actually necessary for any individual operation. This provides for increasing the speed of operation and at the same time assuring a full extent of travel for the maximum height of pile of work material. In accordance with this invention a top stop is incorporated which is adjustable over a substantial range,

for example about one inch, a typical machine having amaximum reciprocating movement of about two and onehalf inches so that the machine can be readily adjusted for most economical operation on work piles of varying height.

Referring to Figs. 2, 3 and 17, the main actuating treadle for the machine is shown at 325 in the form of a substantially U-shaped bar pivotally supported on yokes 326 secured to the bottom of the main frame, the treadle extending outwardly beyond the front wall 11 although within the overhang of the work table 17. Compression spring 328 normally pulls the treadle toward its raised or neutral position, against the action of which it is depressed by the foot of the operator.

This motion is transmitted through push rod 330 which has a free sliding tit within socket 332 as shown in Fig. 17. Socket 332 is pivotally attached as shown at 333 to a beam 335 which has an elongated slot 335 and is mounted for vertical swinging movement about stem 337 passing through the slot. A tension spring 338 tends to draw the beam toward the right as shown in Fig. 17, and this motion is opposed by means of a pull wire 340 which isy connected to a stem 342 (Fig. 6) passing through the front wall of the machine and on the outer end of which control knob 345 is located. This knob carries a rearwardly extending pin 346 which may be seated in either a shallow recess 347 or a deep recess 348 formed in the frame 11 which thus selectively positions the beam in either its forward or left hand position as shown in Fig. 17, or its rearward or right hand postion. The left hand position corresponds to individual or single cycle operation, while the right hand position provides for continuous operation.

The beam is formed in an intermediate portion with at face 350 (Fig. 17) which engages beneath a pin 351':

integral with a lever 353 (Fig. 22) which in turn is pinned by means of pin 354 to a stub shaft 355 rotatably mounted in the right hand wall of the power pack 35.

Upon the inner side of the power pack, an arm 356 is pinned to shaft`355 by means of pin 357 and is formed with a downwardly extending arm 358 which has a forkedi open end 359 engaging over a pin 360 which is xed to'4 and movable with a link 362. The pin 360 is normally urged toward the front wall of the power pack by means,

ofythe spring is fixed to `a suitable abutment pin 367 mounted inA bracket 368 `secured on the bottom of the i power pack (Fig. 23).

At` its-forward end, the link 362 is slotted as shown at-37ll and engages over a pin 371 which is fixed to a shift yoke 373 rotatably supported on the, bracket 368 for rotationabout a shaft375. The shift yoke has a forked and bifurcated upper end as shown at 376 (Figs. 18 and 23), the forked ends engaging over oppositely extending pins 377 carried on the valve shaft control `member 261 of directional valve 200. Thus a rocking motion of the shift yoke 373 as produced by means of the travel of link 362 and pin 371, will provide for-shifting the valve member 201 of the directional control valve between its down and up positions respectively..

From the above it will be apparent thatan upward or clockwise swinging motion of the beam 335 as shown in Fig.. 17 will impart a counterclockwiseV motion to pin 351, and through it a similar motion of shaft 355 and of the inner arrn 358. The forked ends 359 of such inner arm rotating in a counterclockwise direction (Fig. 18) cause a travel of pin 360 and thus of link 362 toward the right as seen in the ligure, against the action of the tension spring 365. A spring 380 extends between a recess 3BE on pinl360, and arecess 382 in pin 371 (Fig. 23)' which is fixed in the shift yoke 373. Thus through the action of spring 380, `the pin 371 is yieldingly maintained in fixed relation in the slotted end 370 of link 362, so that movement of the, link as described causes a corresponding eounterclockwise movement of the shift yoke 373, thereby moving Vthe valve member 201 into its left hand or down position. The lluid is then supplied to the piston 218 `in, the direction to develop a downward travel of the krail assembly in the manner already described.

In order to latch. the controls in this position, allowing the operator to remove his foot from the treadle while providing for continuance of the stroke of the machine, suitable latch meehanismis provided. This embodies a shift lever latch member` 390 on the inside of the power pack which is rotatably mounted on stud 391 extending into bracket 368. The upper end of the shift lever latch istbifurcated as shown as 392 in `Fig. 22 and the two arms thus provided are apertured to be received over pin 360, in straddling relation with respect to link 362. The shift lever latch 390 thus rocks in corresponding relation to the arm 358 but in the opposite direction. At its lower end, l

the member 390 is formed with a notch 395 which is adapted to be engaged by a lockingrnember 397 mounted by means of bolt 398 upon bracket 368 and is` normally urged towardy locking position by compression spring 399.

By reference to Fig. 18 it will be apparent that with thev treadle being actuated to cause a counterclockwise rotation of arm 358 as already described. to initiate a downward operating stroke, the shift lever latch 390 will rockin a clockwise direction sufciently to allow the lock 397 to engage in the notch 395thereby retaining the lever 390 in its displaced position.

When so locked, the valve shaft stem 201 will be retainedin its shifted or left hand position (Fig. 18) as already described, and the machine will thus continue in its downward stroke of movement v/ithout further manipulation on the part of the operator. When the operav utilizing this-pressure.. increase vto effect-- release of t thel latch lock 397. For this purpose a pressure tube 405` comunicates with the T-fitting 287, and leads into a pressure chamber 406 (Fig. 19) which is formed in the bracket 36S. This chamber receives an operating pin 488 which operates as` a pressure plunger, the pin having a rounded lower end adapted to engage the latch lock 397 in the direction to effect release thereof. Also, as shown in Fig. 18 a relief port dit) is provided and is uncovered by the pin 403 after it has traveled beyond its normal motion in releasing the latch for emergency relief purposes.

ln operation, the normal pressure with the piston is insufficient to effect a releasing movement of pin 408 and thus the latch lock 397 is normally effective during the down stroke. When the rail assembly reachesits bottom position, however, the rise in pressure occasioned thereby is sufficient to force pin 408 downwardly to move the latch lock out of its locking position, with the result that spring 365 is then free to draw its pin 363 forwardly, moving link 362 to the left as shown in Fig. 18, and thereby causing a rocking of the shift yoke 373 from its down position, in a clockwise direction, and into its up position. This immediately effects a reversal of flow and fluid is then supplied by th directional valve to the lower side of the piston and the return stroke begins.

lt will also be evident that if some excessive load should be encountered in the downward travel of the rail assembly, such as to impede its downward travel, a similar high pressure condition would develop which would cause the same pressure release of the latch lock 397, with a corresponding reversal of the directional valve to cause the downward travel of the machine to be stopped and to cause it to return to its up or neutral position. Thus an efcctive safety feature is incorporated in the functioning of the machine as well as a variable bottom stop.

In the event that for any reason the rail assembly should fail to return in its upward stroke in the manner described when it encounters an obstruction, a still higher pressure would develop and be transmitted through line 40S to the pressure chamber 486, causing a further downf ward actuation of pin 468 against spring 399, sufiiciently to uncover in part at least the escape port 410. This would allow escape of pressure fluid into the reservoir without the building up of dangerously high or excessive pressure Within the system.

Upon the rocking of the shift yoke 373 to its up position, its lower end rotates clockwise as shown in Fig. 18 and is provided with a notch 420 which is engaged by a locking member $22 fixed to shaft 423 which passes through the wall of the power pack. On the outside thereof, a lever 424 is secured to the shaft, and is normally biased to rotate in a clockwise direction as Shown in Fig. 17 by means of tension spring 425. lt also carries a forwardly projecting finger 427 in which there is mounted an adjustable set screw 423 for accurately determining the point of release thereof.

It will be evident that having been latched in its up position, the shift yoke 373 will be held therein by means of its lock 422, and the machine will thus continue on its upward stroke until such lock is released, to allow the shift yoke to return the directional valve from up toward its neutral position.

This release of the lock is effected by a member which travels with the rail assembly, but the position of which, relative thereto is adjustable in order to vary the upper limit or upper stop position of the assembly. For this purpose the upper boss 57 on the right hand side of the cross head. 56 is formed with an upwardly extending portion 430. An adjustable spider 432 is rotatably received over the post 2S and rests upon the upper -end of the extension 439, being held against vertical travel by means of collar 433 while being free to rotate on the post.` Thespideris provided at its` lower periphery with a series of notches 435 (Fig. 6) in one of which there is engaged a spring latch arm 436 having an operating knob 437 accessible from the righthand side of the machine through an aperture 438 therein. The spider has a series of arms 440 extending radially outwardly thereof and at progressively different elevations thereon. Thus by releasing the latch 436, the spider may be manually rotated on post 25 to bring a selected one of its arms 440 into operative position for actuating the control mechanism.

The selected or operative one of spider arms 440 occupies a position in vertical alignment with a fiat surface 445 on the lower side of beam 335 as shown in Fig. 17. It is also in position to engage the lower end of the adjusting screw 428 as similarly shown.

In operation, and assuming the beam to be in the position shown providing for single or non-repeat operation, the spider arm 440 travels upwardly with the upward travel of the rail assembly and as it reaches the upper end of its stroke, it iirst engages the dat 445 on the beam, to eifect a pivoting of the beam about its pin support 337. This action lifts pin 351, rotating lever 353, shaft 355 and arm 358, which motion is correspondingly transmitted to pin 360 and link 362. Link 362 is thereupon moved toward the right as shown in Fig. 18 and tension is applied to spring 380, tending to pull pin 371 and shift yoke 373 toward neutral position. However such motion of the shift yoke is prevented by its latch 422 which up tothis point has not yet been released.

Upward travel o fthe arm 440 and of the beam 335 thus continues stretching spring 380 and moving link 362 but with pin 371 merely riding outwardly of the forked end of the link and without movement of shift yoke 373. When however a position of link 362 corresponding to the neutral setting of the valve stem 201 is reached, the arm 440 engages the set screw 428, causing the rocking of lever 427 in the direction to release latch 422 from notch 42h, thereby freeing the shift yoke 373. The yoke immediately shifts from its up to its neutral position, being pulled into this position by spring 380 at which point it is stopped by engagement of its pin 371 in the inner end of the link 362. The machine is thus stopped at the limit of its upward travel and remains in neutral position pending a further treadle actuation by the operator. The set screw 428 is suitably adjusted to release the lock only after the arm 440 has engaged and raised the beam 335 to such position that the link 362 will be in proper location corresponding to neutral position of the directional valve.

By rotation of the spider 432, any desired one of its arms 440 may be selected for actuation of the beam in the manner already described, and thus the top stop position may be readily determined. As a specific example, the positions of spider arms 440 may be spaced from each other over the range as above described to thus establish a selected top position for lthe upward travel of the rail assembly.

When it is desired to actuate the machine for continuous operation, hand knob 345 is adjusted to seat the pin 346 in the deep recess 348, and this allows beam 335 to be drawn to the right as shown in Fig. 17 by means of spring 338 thereby bringing a second liat bearing surface 450 into the vertical line of travel of the spider arm 440. It will be evident that in this position, the upwardly traveling spider arm will engage the surface 450 earlier in its path of movement, and that it will travel upwardv substantially further before it engages the set screw 428 than was the case when the control was set for a single cycle operation. This results in a further upward swinging movement of the beam 335, such motion being transmitted through the path already described to cause the link 362 to travel further toward the right as shown in Fig. 18, and into the position corresponding to the down position of the directional valve in which position lock 397 will latch in as above described. Thus when the arm finally engages set screw 428, releasing the latch 422 on the shift yoke 373, the spring 380 pulls the shift yoke all the way from its up to its down position, thereby initiating a subsequent and successive cycle of operation. In this way the machine is adjusted for continuous operation, performing one cycle immediately following another without separate actuation of the treadle on the part of the operator.

When the machine is in a standby condition, with the pump motor operating but with the control set for single cycle operation and with the treadle raised, it remains with the rail assembly in its top position, the parts at this time being in the position shown in Fig. 17. Should the fluid leak out from beneath the piston 218, allowing the spider arm 440 -to settle downward, that will allow a similar downwardly swinging movement of beam 335 which in turn will be transmitted through the mechanism already described, resulting in a shift of the yoke 373 in the direction from neutral toward the up position. This movement, although relatively slight, will allow a suliicient flow of pressure iiuid to the piston in the up direction to maintain the rail assembly in its fully raised position, this condition thus being maintained indefinitely as long as the pump is in operation.

When however the machine is shut down, i. e., when its uid pump is not supplying fluid under pressure it is desired to avoid having the rail assembly drop toward the table and for this purpose a latch mechanism is provided. As shown in Fig. 17 this mechanism comprises a lever 460 which has an upper bifurcated portion 461 loosely mounted on the outer end of shaft 355 and embracing the lever 353, one arm of which is connected to a tension spring 463 to normally bias the latch in a clockwise direction as shown in Fig. 17. As shown in Fig. 22 the latch has a forwardly projecting nose 465 in the vertical path of the spider arm 440, and is also provided with a depending guide 466 which extends downwardly su-flciently far t to overlie the entire vertical travel of the spider arm.

In the neutral position the parts are as shown in Figs. 17 and 22, and thus upon loss of pressure beneath the piston, the rail assembly will be allowed to fall only sutiiciently to engage the arm 440 upon the nose 465 of the latch, and the rail assembly will thus be held mechanically adjacent its top position.

In order to provide for withdrawal of the nose 465 to a clearance position upon actuation lof the machine, the latch -is formed with a forwardly projecting part 467 which overlies pin 351 on the inside of the yoke 353 as shown in Fig. 2l. From this it will be apparent that upward travel of pin 351 with corresponding counterclockwise rotation of lever 353 will result in the overhanging end of pin 351 engaging the arm 467 of the latch, causing it to rock likewise in a counterclockwise direction against the bias of spring 463, and thereby to swing its nose 465 to a clearance position allowing the downward passage of arm 440. The extension 466 is provided to assure that even though the beam moved downwardly in the course of the cycle, the latch will always remain on the same side of the arm 440, the arm merely sliding upwardly against the extension on its upward travel and passing freely over nose portion 465 into the neutral position as shown in Fig. 17, the lower side of the nose 465 being suitably shaped to allow such free upward travel of the spider arm. When the pump is restarted after a period of shutdown, the slightly lowered position of the beam 335 resulting from the resting of the spider arm 44? on lug 465 will open the directional valve enough to supply iiuid in the direction to raise the piston.

Referring now to the emergency stop operations it is desired to provide for the stopping of the motion of the machine at any desired point on its downward or working stroke, under the control of the operator. This control is such that the operator by actuating the control can stop and retain the rail assembly in any desired position, following which he can release it for either completion of the stroke from the point at which it wasinterrupted, or cause it to return toward its top or neutral l position without completion of the stroke.

`v This is accomplished by an emergency treadle 475 (Figs. 2 and 3) which is suitably pivoted `in yoke 476 carried by the frame and normally biased to neutral po sition. Actuation of the treadle causes an upward movement of push rod 478 which has sliding engagement in a socket 480 (Fig. 17). The socket is pivotally attached by means of pin 481' to a lever 482` pinned `by means of pin 483i` to shaft 484, the shaft extending through the side wall of the power pack and having a lever 48S (Fig.` 18) fixed thereto yby means of pin 486 on' the inside of the power pack.

Lever 48S is adapted to engage against pin 371 carried by shift yoke 373. Thus upon actuation of the emergency treadle 475,` lever 485 is caused to rotate in a clockwise direction, and to thus Withdraw pin 371 from the forked arms 379 of the link 362, against the` action of spring 38d, This causes an immediate and direct shifting of the yoke 373 from its down to its neutral position.` Thus as long as the emergency treadle is held in its` depressed position, the control valve remains in neutralA and the piston and rail assembly are stopped in any intermediate position of their downward travel. Upon release of the foot treadle from this position, the parts return to their original positions and the downward travel of the piston is continued' from the point at which it was stopped to complete the cycle.

When however the emergency treadle isdepressed further, to its lowermost position, a further clockwise rotation of lever 48S takes place. This actuation provides for the direct rotation of the shift yoke 373 to its full up position, thus causing the reversal of the stroke from whatever position the piston occupied at the time when the emergency treadle was depressed. In addition, the arm 485 has pivoted thereto a rod 490 (Fig. 18) which is looped over apin 491 fixed in an arm` formed integrally with the latch lock member 397L It will be apparent that the partial rotation of lever 485 as describediin connection with the stoppage only of the travelof the piston, does not pick up pin 491, but when the lever is fully depressed, the end cf the loop picks up the pin,49l and rotates the latch 397 in the direction to release the lock. Thus the directional valve stem 201 is allowed to remain in its up position, the rail assembly returnsito its fully raised or neutral position, and further operation of the machine terminates.

It` will thus be apparent that the invention provides a hydraulic paper drill which is simple, safe and reliable in operation, which can be readily constructedy and repaired when necessary, and which is highly advantageous in the range of its adjustment and flexibility to meet different conditions in use.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without, departing from the scope of the invention which is defined in the appended claims.

What is claimed is: p

l. ln a machine of the character described having a base and a working member supported for work and return strokes with respect to said base, the combination of a hydraulic motor for effecting said movement of said working member, means for supplying hydraulic fiuid `to said motor at a substantially constant rate, means forming a bleed passage for said fluid of predetermined flow area effectiveto establish a maximum rate of supply of said fluid to said motor and resulting predetermined maximum rate of travel of said working member, means forming a bleed orifice in the line of flow between said` motor and said bleed passage, means responsive to increase in the work load on said working member for restricting said orice sufficiently to. maintaina substantially. uniformV pressure effectivey pn'` said. bleed. passage and thereby maintaining an effectively uniform rate cf supply of said `uid to said motor for travel of said working member at said predetermined rate, means responsive to further increase in hydraulic pressure above a predetermined value to reverse the direction of flow of said uid to said motor to cause a return stroke of` said working member, and selectively operable means forming a by-pass connection to said bleed passage around said orifice to prevent such further increase in pressure and thereby to hold said working member at the end of said work stroke thereof.

2. In a machine of the character described having a base and a working member supported for workiand return strokes with respect to said base, the combination of a hydraulic motor` for effecting both said strokes of said working member, means for supplying hydraulic fluid to said motor at a substantially constant rate, means forming al bleed orifice for said fluid to reduce the supply thereof to said motor, means responsive to increase in hydraulic pressure resulting from increase in the work load on said working member for restricting said orifice sufficiently to maintain a substantially uniform rate of flow therethrough and thus to maintain a substantially uniform rate of supply of said fluid to said motor and a substantially uniform rate of travel of said working member, means responsive to further increase in hydraulic pressure above a predetermined value to reverse the direction of flow of said fluid to said motor to cause a return stroke of said working member, and selectively operable means forming a by-pass bleed passage around said orifice to prevent such further increase in pressure and thereby to hold said working member at the end of said work stroke thereof.

3. In a machine of the character described having a base and a working member supported for work and return strokes with respect to said base, the combination of a hydraulic motor for effecting both said strokes of said working member, means for supplying hydraulic fluid to said motor at a substantially constant rate, a positive stop on said base for engagement with said working member to establish the end of the work stroke thereof with resulting increase in the hydraulic pressure, means responsive to said increase in hydraulic pressure above' a predetermined value to reverse the direction of flow of said fluid to said motor to cause a return stroke of said working member, and selectively operable means for opening a bleed passage for said fluid to prevent said increase in hydraulic pressure and resultant operation of said reversing means and thereby to hold said working member at the end of said work stroke thereof.

4. In a machine of the character described having a base and a working member supported for a work stroke with respect to said base and a return stroke to an inoperative position, the combination of a hydraulic motor, means for supplying hydraulic fluid to said motor, valve means including a shiftable valve member having forward and reverse positions for alternatively connecting said fluid to opposite ends of said motor to cause said work and return strokes of said working member, means defining a neutral position for said valve member effective to hold said working member stationary, means responsive to completion of said return stroke of said Working member to said inoperative position for shifting said valve member to said neutral position thereof to stop said working member in inoperative position, latch means responsive to completion of said return stroke for mechanically retaining said working member in inoperative position -in the absence of fluid pressure, and means responsive to shifting of said valve member to said forward position for releasing said latch means to effect a further work stroke of` said Working member.

5. In a machine of the character described having a base and a working member supported for a downward Work stroke withrespect to said base and a return stroke t0'4 an upper inoperative position, the combination of a hydraulic motor, means for supplying hydraulic iluid to said motor, valve means including a shiftable valve member having forward and reverse positions for alternatively connecting said fluidto opposite ends of said motor to (cause said work and return strokes of said working member, means deiining a neutral position for said valve member eifective to hold said working member stationary, means on said Working member for terminating said return stroke of said working member in said inoperative position by effecting movement of said valve member to said neutral position thereof, latch means responsive to said termination of said return stroke for mechanically retaining said working member in inoperative position in the absence of uid pressure, means responsive to gravity movement of said working member against said latch means for shifting said valve to said reverse position to raise said working member from said latch means upon restoration of Huid pressure, and means responsive to shifting of said valve member to said forward position for releasing said latch means to effect a further work stroke of said working member. n

6. In a machine of the character described having a base and a working member supported for a work stroke with yrespect to said base and a return stroke to an inoperative position, the combination of a hydraulic motor,

`n1eans for supplying hydraulic fluid to said motor, valve means including a shittable valve member having forward and reverse positions for alternatively connecting said fluid to opposite ends of said motor to cause said work and return strokes of said working member, means deining a neutral position for said valve member effective to hold said working member stationary, means on said working member for terminating said return stroke of said working member in said inoperative position by effecting movement of said valve member to said neutral position thereof, latch means responsive to said termina- 'tion of said return stroke for mechanically engaging said terminating means to retain said working member in inoperative position in the absence of fluid pressure, means for adjusting said terminating means on said working member to change the location of said inoperative position, and means responsive to shifting of said valve member to said forward position for releasing said latch means to effect a further work stroke of said working member.

7. In a machine of the character described having a base and a working member supported for a work stroke with respect to said base and a return stroke to an inoperative position, the combination of a hydraulic motor, means for supplying hydraulic uid to said motor, valve means including a shiftable valve member having forward and reverse positions for alternatively connecting said uid to opposite ends of said motor to cause said work and return strokes of said working member, means defining a neutral position for said valve member effective to hold said Working member stationary, means for operating said valve member, means on said working member for terminating said return stroke thereof in said inoperative position by actuating said operating means, selective means for adjusting said operating means between a single cycle position responsive to actuation by said terminating means to shift said valve to said neutral position with resulting stopping of said working member and a continuous position responsive to actuation by said terminating means to shift said valve member to said forward position with resulting repetition of said work stroke of said working member, latch means responsive to said termination of said return stroke of said working member for mechanically engaging said terminating means to retain said working member in inoperative position in the absence of fluid pressure, means for adjusting said terminating means on said working member to change the location of said inoperative position, and means responsive to shifting of said valve member to said forward position for releasing said latch 18 means to eieeta-further work stroke of said Working member.

8. ln a machine of the character described having a base and a working member supported for work and return strokes with-respect to said base, the combination of a hydraulic motor for eifecting both said strokes of said working member, means for supplying hydraulic fluid to said motor at a substantially constant rate, pressure responsive means controlling the return flow of said fluid from said motor during said work stroke to establish a predetermined minimum Work load effective on said motor, means forming a bleed passage for said iluid of predetermined flow area connected with the pressure side of said motor during said work stroke to establish a maximum rate of supply of said uid to said motor and resulting predetermined maximum rate of travel or" said Working member under said minimum work load, means forming a bleed oriiice in the line of flow between said motor and said bleed passage, means responsive to increase within a predetermined range of the pressure in said tiuid caused by increase in said work load for restricting said orifice sufficiently to maintain a substantially uniform pressure effective on said bleed passage and Vthereby maintaining an effectively uniform rate of supply of said fluid to said motor for continued travel of said working member at said predetermined rate on said work stroke, means responsive to increase in said liuid pressure to a value substantially above said range for reversing the direction of flow of said fluid to said motor to cause the return stroke of said Working member, and means for discontinuing the flow of fluid through said orilce on said return stroke to provide for full rate of supply of said uid to said motor and increased rate of travel of said working member on said return stroke.

9. In a machine of the character described having a base and a Working member supported for a work stroke with respect to said base and a return stroke to an inoperative position, the combination of a hydraulic motor, means for supplying hydraulic fiuid to said motor, valve means including a shiftable valve member having forward and reverse positions for alternatively connecting said uid-tg-opposite ends of said motor to cause said work and return strokes of said working member, means deiining a neutral position for said valve-member effective to hold said working member stationary, means for retaining said valve member in said forward position during said Work stroke, means responsive to increase in the supply of said fluid to said motor above a predetermined value during said work stroke for releasing said retaining means and causing shifting of said valve member to said reverse position to initiate the return stroke of said working member, means responsive to completion of said return stroke of said working member to said inoperative position for shifting said valve member to said neutral position thereof to stop said v working member in inoperative position, latch means responsive to completion of said return stroke for mechanically retaining said working member in inoperative position in the absence of fluid pressure, and means responsive to shifting of said valve member to said forward position for releasing said latch means to effect a further work stroke of said working member.

References Cited in the le of this patent UNITED STATES PATENTS 1,235,610 Staub Aug. 7, 1917 1,910,766 Hobson May 23, 1933 1,911,138 Clute May 23, 1933 1,924,138 Strawn Aug. 29, 1933 1,927,583 Ernst Sept. 19, 1933 1,931,452 Wheeler Oct. 17, 1933 1,972,462 Schafer n Sept. 4, 1934 (Other references on following page) UNITED STATES PATENTS 2,276,358 Vickers Mur. 17, 1942 1,932,711 V' k D 4y 1934 2,288,830 NYC July 7, 1942 2,111,964 Cmrs Macgg, 1938 2,480,527 Wachter Allg- 30l 1949 2,167,279 Manny July 25, 1939 5 FOREIGN PATENTS 2,173,817 Barney Sept. 26, 1939 2,192,778 stacy Mar. 5, 1940 4375 Great Bumm 1903 2,253,617 Grth Aug. 26, 1941

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