US2624319A - Power feed apparatus - Google Patents

Description

Jan. 6, 1953 HE 2,624,319

POWER FEED APPARATUS Filed July 51, 1946 5 Sheets-Sheet l HIE UNDER PRES-$025 eaumrve AND 6965 INVENTOR Do/v HA'YEQ,

ATTORNEY '5 Sheets-Sheet 2 D HEY\ER POWER FEED APPARATUS RV mm Jan. 6, 1953 Flled July 51 1946 Jan. 6, 1953 D HE POWER FEED APPARATUS 5 Sheets-Sheet 5 Filed July 31. 1946 INVENTOR DON HEYEIQ,

ATTORNEY Jan. 6, 1953 D, HEYER POWER FEED APPARATUS 5 Sheets-Sheet 4 Filed July 51, 1946 INVENTOR .Dou .HEYEAZ,

ATTORNEY Jan. 6, 1953 HEYER POWER FEED APPARATUS 5 Sheets-Sheet 5 Filed July 51, 1946 r/TlillllilYfiilTI/IIIII INVENTOR DON HE Yse,

ATTORNEY Patented Jan. 6, 1953 UNITED s'rArs parser OFFICE v 2,624,319 rowan FEED APPARATUS Don HeyerILos Angeles, Calif. Application July 31, 1946, Serial No. 687,401

1 V This invention relates to fluid actuated apparatus for producing relative advance and withdrawal between a tool and work material upon which the tool is to operate. The apparatus of this invention is particularly adapted for application to a drill press having a rotating bit; although it may readily be applied to many types of. operating machinery, such as machine tools, bending and forming machines, transfer conveyors, hoists, boring machines, and similar apparatus wher movement of an operating member is to be controlled. More particularly, this invention relates to such apparatus employin fluid actuated driving means.

In general, the apparatus herein disclosed coma prises an assembly adapted to be attachedto a standard machine, although it will be understood that the. apparatus may be fabricated as a part of the machine if desired. Fluid actuated driving means are employed, preferably in the form of a cylinder and piston, the power-transmitting fluid preferably being compressed air.

Theapparatus of this invention embodies numerous features ofadvantage, among which are a valve designed to be actuated either mechanically, as by hand, or electrically through a solenoid, said valve operating to control the application of air to the piston; and stabilizing means in the form of a velocity responsive damper, preferably of .the viscous fluid type, said stabilizing means being arranged to be coupled to the driwng means, i. e., the air driven piston, at a variable predetermined point in the travel in-the piston.

Other features of this apparatus are an electrical control, use of which is optional, by means of which intermittent and momentary relative withdrawal between tool and work may be effected during the machine operation; a clutch whereby the air-powered driving meansv of the machine may be quickly ole-coupled from the machine, thereby permitting the machine to be manually operated; limiting means both mechanical and, optionally, electrical for reversing direction of motion of the piston at a variable, predetermined point in the tool-advancing movement of the piston; a set of bushings, by proper use of which the apparatus may be adapted for mounting-on machines having varying sizes of spindle control shafts; pliant mounting means whereby the apparatus may be easily and properly mounted on any given machine; and the integral unitary construction of power cylinder and valve cylinder having a common wall with ports therethrough, thereby eliminating cumbersome conduits between valve and power cylinder,

In controlling movement of a tool throu h use of, externally powered driving means, itmaybe desirable, to, provide, control means permitting optlonallyeither mechanical control of the driv- 5 claims. (01. 121 45) 2 ing means, or alternatively electrical control thereof.

.To this end, it is an object of this invention to provide a valve for controlling admission of air to a cylinder,.whichvalve may be controlled by a mechanical member, or alternatively by an electrical means such as a solenoid.

It is another object to utilize such control over air admission to the cylinder to provide automatic reversal of the advancement of the tool, whereby the hands of the operator may be freed for holding or otherwise guiding the work.

In the progression ofv a tool through material being worked, uneven impedance to advancement of the tool may be encountered. With substantially constant driving pressure from the powered driving means, such a phenomenon would result in uneven travel of the tool through the work. That is to say, in regions of low tool impedance the tool would move ahead rapidly, and upon encountering high impedance would be brought to a sudden virtual stop, which might result in strain to the machinery or in unsatisfactory finished work.

It is an object of this invention to obviate any such difficulty as above by the provision of stabilizing means coupled to the powered driving means whereby substantially constant tool velocity may be maintained regardless of varying impedanc encountered.

In the present invention such a stabilizing means comprises a viscous fluid damper, which applies a damping force to the driving means increasing rapidly with increased velocity of the driving means, thereby tending to stabilize the velocity of the driving means.

Another object of the invention is to provide an arrangement in which the above described stabilizing means or damper may be coupled to the driving means at a variable, predetermined point in the tool advancing movement of the driving'means; thereby permitting relatively rapid movement of the tool to the surface of the work, and relatively slow, stabilized movement of the tool while it operates upon the work.

As the tool operates upon the work, it is desirable. to intermittently and momentarily lift the tool from the work. This not only aids in cooling thetool, but also breaks up cut-away material ,into short, easily disposable shavings of lessened danger to personnel.

Accordingly, it is an object of this invention to provide means, preferably including an electrical circuit, for controlling the valve of this invention whereby the tool is intermittently and momentarily lifted from its operation upon the work. I

For employment in the above mentioned electricalcontrol-circuit there is provided a readily accessible limit switch, the. settingof which'may 3 be altered to give variable control of the limiting position at which it is desired that the tool should be automatically withdrawn completely from the work.

Under certain circumstances it is desirable that longitudinal movement of the tool be controlled manually, without use of the powered driving means of this invention.

To this end, it is an object to provide a simple and effective clutch whereby the driving means may be quickly de-coupled from the machine spindle control shaft.

Many machine tools now in use, particularly drill presses, employ control shafts of different diameters. To render the apparatus of this invention adaptable to many standard drill presses, it is an object to provide means for adapting the output member of the driving means of this invention to fit numerous different diameters of drill press spindle control shafts. In the embodiment to be described such adapting means comprises bushings of various sizes to fit various sizes of spindle control shafts.

To further aid in cooling the tool during its operation upon the work, and to disperse small 'by the employment of discharge air from the driving cylinder, carried to the vicinity of the tool through a suitable conduit.

Inasmuch as the assembly of this invention is adapted for mounting on a wide range of types of machines, it is an object of this invention to provide pliant mounting means whereby the assembly will automatically, within relatively narrow limits, adjust itself to mounting on any given machine. This pliant mounting means in the instant invention comprises judiciously disposed, cylindrical, resilient bushings interposed between the assembly and the drill press proper.

It is a further object to eliminate bulky and expensive conduit fittings between a fluid cylinder and its control valve by fabricating the valve as an auxiliary cylinder integral with the power cylinder, said cylinders having a common wall with fluid ports therethrough.

This invention possesses many other advantages and has other objects which may be made -more easily apparent from a consideration of one embodiment of the invention. For this purpose there is shown in the drawings accompanyingand forming part of the present specification, a form of this invention exemplified as applied to a drill press having a spindle which controls the longitudinal position of a drill bit with respect to the work into which the bit is designed to penetrate. This form will now be described in detail, illustrating the general principles of the invention. It is to be understood that, while exemplified in apparatus applied to a drill press, the teachings of this invention are similarly applicable to many types of machines and machine tools; therefore this detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referrin to the drawings:

Figure 1 is a side elevation of a drill press with the powered driving apparatus of the present invention mounted thereon;

Figure 2 is a sectional elevational view taken along line 22 of Figure 1, showing a portion of the mounting means for securing the apparatus of this invention to a drill press;

Figure 3 is a sectional view taken along line 3-3 of Figure 4, showing the driving cylinder and piston, together with the rack and pinion connection to the clutch shown in Figures 4, 5 and 6;

Figure 4 is a sectional view taken on line 4-4 of Figures 1 and 3, showing particularly the clutch arrangement and related gearing assem-' bly through which motion of the driving means is transmitted to the conventional spindle control shaft of the drill press;

Figure 5 is an elevational view taken along line 55 of Figure 4, showing the clutch control handles positioned for powered operation of the drill, i. e., for clutch engagement;

Figure 6 is an elevation partially sectioned, taken along line 6- 6 in Figure 5;

Figure 7 is a section along line '!1 of 'Figure 3;

Figure 3 is a sectional view taken along line 88 of Figure '7, showing the air valve actuated to bit-advancing position;

Figure 9 is a fragmentary sectional view showing part of the valve of Figure 8 disposed in a position attained momentarily during transfer from bit-advancing to bit-withdrawing position;

Figure 10 is an enlarged sectional view of the valve of Figure 8, with the parts shown in bitwithdrawing position;

Figure 11 is a section taken on line lI-ll of Figure 10, showing the lever through which movement of the solenoid plunger is transmitted to the valve;

Figure 12 is a section taken on line l2l2 of Figure 7, showing the viscous fluid damping or stabilizing means;

Figure 13 is a circuit diagram illustrating the electrical control means of the apparatus;

Figure 14 is a View along line |4-|4 in Fig ure 4, showingthe limit switch which may be mounted on the housing of the coupling means shown in Figure 4;

Figure 15 is an enlarged sectional view taken on line l5-|5 of Figure 14 and includes portions of the housing shown in Figure 4; and

Figure 16 isa view taken along line Iii-I 6 of Figure 15.

Referring now specifically to Figure 1, there is shown a conventional form of drill press l0, having an upright standard 11,- a drill rotating motor l2, and a drill bit I3. Bit I3 is raised and lowered in accordance with the angular position of rotatable spindle control shaft l4 controlled by handle I 5, which latter may form a portionof the control apparatus of this invention.

Mounted on the conventional drill press thus far described is the air-powered driving means 5- of this invention, including a cylinder I! having end plates 18 and [9, to which is secured a clutch housing 20, the latter being mounted over spindle control shaft M. A suitable source 2| of air under pressure is connected through pipe 22 to a valve 23 preferably formed as a unitary structure with cylinder l1 and utilizing end plates l8 and I9.

Air from source 2|, applied selectively through valve 23 to cylinder l7, serves to reciprocate a rack 24 coupled through gearing and clutch means in-housing 2ll'to shaft 14, thereby raising and lowering drill bit 13. Air exhausted from cylinder I! returns through valve 23 to outlet pipes 25 forming a common-duct at 26'leading to a hole in hit guide'2l' aflixed above the work 28.

In this manner; an intermittent flow of air is discharged againstthe rotating bit l3 during operation thereof.

The several portions of the assembly thus far described generally will now be fully described in detail.

The driving means It including cylinder I1 is mounted on the standard H, as shown in Figure 2. Clamping means 29, including a spliit ring 29a and a clamping bolt as, serve to anchor .adjustably on standard H a clamp-3|, which in turn supports cylinder H, by the engagement of clamp 3| with bolt 32, one of the bolts which serves to hold together end plates l8 and I9. Of the remaining three bolts 33, 3t and 35, bolts 33 and 35, situated respectively at the top and bottom of cylinder l1, continue forwardly of plate l8 and serve to strengthen the apparatus through connection with housing 25.

Referring particularly to Figure 3 showing the driving means 16 and housing 26, it will be seen that the right hand end of rack 24 constitutes a piston rod to which is attached, within cylinder IT, a piston 36 having a piston ring 31 forming an air-tight, slidable seal between piston 35 and the inside wall of cylinder i1, and preferably in the form of a toroid of elastic material such as oil resistant synthetic rubber. As is known in the art, ring 31 is free to roll slightly in annular groove 38 in the edge of piston 35. In so doing it stretches, thereby forming a good :air seal between piston 56 and the inside of the wall of cylinder H.

Inasmuch as driving means [6 is mounted on one portion of drill press I6 and. housing 26 is mounted on anotherportion thereof, it is desirable to provide that the mounting and other connections between driving means l6 and housing 26 shall be pliant within small limits. To this end the engagement of rack 24 with piston 35, and the port 39 through which rack 24 emerges from cylinder I? include pliant mounting means. Such a mounting means is shown, for ex mple, at end 45 of rod 33, in the form of a sleeve dl of resilient material, such as oil resistant synthetic-rubber, interposed between end 46 and opening 42 in housin 26 in which end 46 is received. The pliant mounting means includes, in addition to resilient sleeve 4|, inner and-outer metal sleeves 43 and 44, respectively. Similar pliant mounting means are provided at 45 on extended bolt 35, and at 56 where rack 24 is attachedto piston 36; also around port 39 where rack 25 emerges from cylinder llthrough end plate |8. It will be noted that end plate H3 at port39 includes a groove 4! and elastic ring 48 functioning in the manner described for groove 38 and elastic ring 3! of piston 36.

Teeth 49 of rack 24 co-act with pinion 50 mounted on shaft journaled in housing 26, being held thereagainst by a saddle shaped roller 52 (Figure l) mounted on shaft 53 likewise journaled in housing 26.

To transmit reciprocation ofthe rack 24, impelled by air-powered driving means It, to spindle control shaft l4, a gear 54 also mounted on shaft 5| meshes with a gear 55 journaled coaxially around shaft l4 and coupled thereto through a clutch 56 to be presently described in connection with Figure 4. Extreme forward movement of piston 36 necessitates the inclusion of a hollow boss 51 on housing '20 for the reception of the end of rack '24.

Clutch 56 is shown in detail in Figure 4, which alsoillustrates the manner in which housing 26 ismountedon shaft |4.

formed integral with gear 55. that sleeve 61 extends axially a short distance To accommodate the apparatus of this invention to spindle control shafts of various diameters, a bushing 58 is provided, which is secured to shaft M by means of set screw 59. Mounted on bushing 58 and secured thereto by a set screw 60, is a sleeve 6| having an annular shoulder 62 at one end thereof. On the other end of sleeve 6| from shoulder 62 is mounted, by means of set screw 63 and threads '64, a collar 65 from which extends a control handle l5. The outer surface of sleeve 6| constitutes a bearing surface on which is rotatably mounted a sleeve 6i preferably It will be noted beyond housing 20, where it contacts a collar 68 interposed between collar 65 and sleeve 6'! and having also a handle '69 extending therefrom. Collar 68 is mounted on sleeve 5| so as to be axially and angularly slidable thereon.

Reviewing the assembly thus far described, it will be seen that sleeve 61, oscillatingin accordance with reciprocation of rack 24 through the coaction of gears 56, 54 and 55, imparts this oscillation to shaft I 4 through sleeve 6|, and bushing. 58, by selective coupling of sleeve 6| with sleeve 61. Such coupling is accomplished through collars 65 and 68 as will be explained in connection with Figure 5.

Selective axial pressure between collars 65 and '68 is effected by the action of a ball 16 (Figuresb and 6) contained in an axial hole 'II in collar 65 and biased against the surface of collar 68 by a spring 12 held in position by an inset screw 13. To relieve pressure on ball 16 against collar 68, a hemispherical recess 74 is provided in which ball 16 may seat when a predetermined angular relation exists between collars 65 and 6-8.

When handles l5 and 69 are juxtaposed, ball 10 register with recess 14 thereby relieving pressure between collars 65 and 68, and shaft i4 is free to turn relative to sleeve 67. Upon relative angular separation of handles 5 and 69, as shown in Figure 6, ball 16 is moved from recess 14, whereupon the pressure of spring 12 against ball 10 and of ball 16 against collar 68 presses collar 68 against sleeve 61, and sleeve '6! against shoulder 62. The frictional engagement thus provided between shoulder 62 of sleeve El and sleeve 61, and between'the end of sleeve 61 and collar 68 serves to clutch sleeve 6| to sleeve '51, whereby movement of rack 24 is imparted to shaft l4. If desired, a pair of pressure-producing means consisting ofthe assembly 16, H, 12, 13 and 14 may be provided as shown in Figure 5, diametrically disposed in collar 65.

Handles l5 and 69, when together, signify Manual operating position, in which driving means l6 is'completely'de-coupled from the drill press. Handles i5 and 69, when separated, as shown in Figures 5 and 6, signify the Powered operating position, in which longitudinal movellrent. of drill bit I3 is controlled by driving means The manner in which air under pressure is admitted from pipe 22 through valve '23 selectively to either side of piston 36 in order to advance or withdraw bit l3 from work 28 will now be described. Referring to Figures 7, 8, 9 and 10, valve 23' is shown comprising a valve cylinder 15 in which reciprocates a valve shaft 1'6 extending externally forward of cylinder 15. Mounted on valve shaft 16 near each end of cylinder 15 are valve piston 11 and I8. Surrounding shaft 16 intermediate pistons 11 and 18, and slida-ble with respect to cylinder 15 and shaft I6, is a valve sleeve I9 riding in inset portion 80 of cylinder I5.

Air from pipe 22 enters cylinder I at inlet port 8| and emerges therefrom at either outlet port 82 or outlet port 83, each of which communicates, respectively, with an end of cylinder II forming part of driving means I6. Whether ai-r entering valve 23 through port 8I will emerge from port 83 to advance piston 36, or from port 82 to withdraw piston 36, is determined by the position of pistons 11 and I8 mounted on shaft I6. In Figure 8 valve 23 is shown in bit-advancing position, wherein air passes from inlet port 8! through an axial groove 84 in valve sleeve I9, to an axial groove 85 in portion 80 of cylinder I5, intothe body of valve 23, and thence out port 83 and into the right hand end of cylinder I'I, thereby advancing piston 36. With the advancement of piston 36 in cylinder II, air emerges from cylinder I! through port 82, into the body of valve cylinder I5, and out exhaust port 86 to exhaust pipe 26, through which it is conveyed to hit guide 21 (Figure l) where it cools bit I3 and disperses small shavings.

When valve '23 is in bit-withdrawing position (as shown in Figure a converse flow of air occurs. Air enters at port 8 I, flows through axial groove 84 into the left hand body portion of cylinder I5, and out port 82, into cylinder II, causing piston 36 to withdraw. In a similar manner exhaust air passes from cylinder II, through port 83, into cylinder 15, and out exhaust port 81 into exhaust pipe 25-26.

To determine the setting of valve 23, shaft is is manually reciprocated by means of a knob 38. In order that sleeve E9 may move with shaft I6 upon manual reciprocation of the latter, helical springs 89 and 90 disposed around shaft I6 bracket sleeve I9, being biased thereagainst by collars 9I and 92, respectively. movement of sleeve I9 with respect to shaft I6 permitted by the use of springs 89 and 96 is for a purpose to be described in connection with the electrical operation of valve 23 through a solenoid 93, which contrasts with mechanical operation of the valve through shaft I6 and knob 88.

From the above it will be seen that reciprocation of shaft I6, by determining the position of pistons I1 and E8 in cylinder I5, determines the direction of air-impelled movement of piston 36 in cylinder II.

Egress of air from cylinder II through valve 23 may be controlled, if desired, by means of needle valves 94 and 95 located in exhaust pipe 26 immediately adjacent outlet ports 86 and 8'I, respectively.

To provide limiting means for automatically reversing the direction of travel of piston 36 when a variable, predetermined point in the advance of bit I3 has been reached, an arm 96 (Figures 7 and 8) is mounted on rack 24 extending downwardly therefrom toward shaft I8. Arm 96 is bifurcated at 9! (Figure '7) to encompass shaft I6, the sides of which are flattened as shown at 96 for coaction with the inside surface of bifurcation 9'I, thereby preventing rotation of shaft l6 while permitting longitudinal movement thereof with respect to arm 96. Arm 96 actuates shaft 76 during bit-advancing movement of the former through the mediacy of a disc 99 (Figure 8) slidable on shaft I6 and backed by a spring :96 bearing against a collar IOI threadedly mounted on shaft I6 for axial adjustment thereon. Collar IOI' is fixedly mounted on one end of .a tube I03 telescoped over the end of shaft I8.

The limited On the other end of tube I03 is attached the knob 88. Tube I03 has a series of axial grooves I04 on its outer surface coacting with any suitable detent mechanism I05 held in tube bearing housing I06. Bearing housing I06 is mounted on the bottom of housing 20, as shown in Figures 4 and 1.

From the above it will be seen that shaft I6 may be reciprocated in cylinder I5 and in bearing housing I06 either manually through knob 88, or automatically, by pressure of arm 96 against collar IOI through spring I00 and disc 99. Furthermore, the axial position on shaft I5 of collar IEII and associated spring I00 and disc 99, may be altered by rotation of tube I03 through knob 8-8; detent mechanism I05 coacts with grooves I04 to prevent accidental rotation of tube I03, for example by vibration, while still permitting unimpeded longitudinal movement of tube I03 in bearing housing I06.

The provision of spring I00 (and associated disc 99) is to insure that sufiicient energy will be available to actuate valve 23 fully and abruptly from bit-advancing position (Figure 8) to bitwithdrawing position (Figure 10), without the intervention of an indecisive period during which neither port 82 nor 83 is open. That is to say, arm 98 advancing along shaft I6 and contacting collar IOI would, in the absence of spring I00, produce slow actuation of valve 23, and might thereby introduce a stalemate in which neither port 82 nor 83 would be open, thereby stopping further movement of piston 36, rack 24, and, of course, arm 96.

Cooperating with spring I00 to produce rapid actuation of valve 23, is a spring biased detent I9? mounted transversely in shaft I6 and coacting with a circumferential groove I08 on the inner surface of cylinder I5. As arm 96 carried on rack 24 advances, it first contacts disc 99 and then begins to compress spring I00. When a predetermined force on collar IOI has been produced by arm 96 through spring I00, detent I0! is pulled abruptly from groove I08, and shaft I6 is actuated fully to bit-withdrawing position by virtue of the energy stored in spring I00.

The limiting point in the advancement of bit I3 at which arm 96 actuates shaft IE to reverse bit movement is determined by the longitudinal position of collar I8I (and spring I00 and disc 99), which is in turn determined by the rotative setting of knob 88. Thus, by angular adjustment of knob 88, the opertaor may adjust the limiting bit-advanced position of bit I3. An alternative limiting means is available for use with the electrical control of driving means I6, to be described in connection with Figures 13 through 16,

In the mechanical control and actuation of valve 23 thus far described, sleeve I9 responds as though fixed to shaft I6. This response is brought about by the provision of springs '89 and 90, sleeve I9 being sufficiently light with respect to valve shaft assembly I6, 11, I8 and I83 that springs 89 and 90 remain substantially unflexed.

To provide for electrical actuation of valve 23, in which full movement of the assembly of shaft I6 is aided by the very flow of air which valve 23 controls, a solenoid 93 is mounted below cylinder I5. On plunger I69 of solenoid 93 is pivotally arranged a lever I I9, pivotally mounted near its midpoint on a shaft I II journaled in the housing of valve 23. A knob-like portion Il2 on lever IIO extends into cylinder 15 and coacts with a slot II3 cut in sleeve I9- (see%Fig'ure 11).

9 It will thus be seen that oscillation of lever IIO by solenoid 93 reciprocates sleeve I9 on shaft 16 and within cylinder 15. It is to permit such relatively limited reciprocation of sleeve 19 on shaft I6 that springs 89 and 90 are provided.

In connection with the electrical operation of valve 23 through solenoid 93, shaft I6 is notched as shown at I I4 and I I5. These notches provide, in connection with an internal annular groove II6 on sleeve I9 a passage for inlet air from port 8| into the body of cylinder 15 prior to the full reciprocation of sleeve I9 in cylinder I5.

This will be understood by a brief description of the electrical operation of valve 23 from its bit-advancing position to its bit-withdrawing position. Such operation shifts valve shaft I6 from the position shown in Figure 8, through that shown in Figure 9, to the position shown in Figure 10.

Let it be imagined that solenoid 93 has been energized to retract plunger I09; the resulting counterclockwise rotation of lever H pushes sleeve I9 to the left in Figure 8 against the bias of spring 89. Referring to Figure 9, lever H0 ha moved sleeve 19 until groove I IS in the sleeve has broken communication with axial groove 85 and is just beginning to register with notch II in shaft I6. At this point air under pressure from inlet port 8I flows into axial groove 84, around annular groove II6, into notch H4, and thence into the left hand end of cylinder I5, where it produces pressure against piston 'I'I, moving shaft I6 to the bit-withdrawing position, shown in Figure 10. With shaft I6 moved to it extreme left position, air from inlet port BI flows through valve 23 and into cylinder I! through port 32, where the pressure produced on the left hand face of piston 36 initiates its bit-withdrawing movement. It is preferred to design the valve so that groove II6 breaks communication with groove 85 before making communication with notch I I4, thereby precluding having air pressure simultaneously against both pistons I1 and I0.

The small amount of fluid trapped between member I8 and sleeve I9 by the interruption of communication between groove H6 and groove 85 does not exert sufficient pressure to prevent movement of the valve assembly to the left in response to the inlet pressure acting on the member TI, it being noted that sleeve I9 is allowed limited movement independently of members I! and I8 since the sleeve floats on rod IS-between springs 09 and 90. I

It will thus be seen that sleeve I9 provides -a means whereby valve 23 may be made virtually self-actuating insofar as movement of the relatively heavy assembly associated with shaft I6 is concerned. That is to say, the relatively light force produced by solenoid 93 acting through sleeve I9 opens a passage to piston 'II, thereby utilizing piston 11 as a valve actuating means as well as a valve opening means. It will be understood that in solenoid actuation of the valve from bit-withdrawing to bit-advancing position, notch I I fulfills the same function as above described for notch II4.

. With solenoid 93 so completelyv de-energized, lever I I0 is free to oscillate with movement of sleeve I9 produced by mechanical reciprocation of shaft I6.

While mechanical control of valve 23 has previously been described, it now remains to'describe electrical control thereof by the circuit of Figure 13 acting through solenoid 93. Before this is done, however, there will be described a velocity responsive, viscous fluid means serving to stabilize advancement of piston 36 as 'bit I3 encounters varying resistance to advancement.

The stabilizing means III of this invention comprises a cylinder II8 filled with viscous fluid preferably mounted below cylinder I1 and disposed symmetrically with respect to cylinder of valve 23. The stabilizer H1 is best seen by reference to Figure 12 which is a view taken along line I2-I2 of Figure 7. In Figure 12, cylinder H8 is shown mounted below cylinder I1 and utilizing end plates I8 and I9 to close the ends thereof. A shaft I I9 is arranged to reciprocate in cylinder H8 and extends externally forward thereof to receive telescoped tube I20. The assembly associated with tube I is physically identical with that shown in connection with tube I03, except for the omission of spring I00 and disc 99; and further description thereof is deemed unnecessary, except for the operaton to be explained hereinafter. I I

Slidably mounted on shaft II9 near the end thereof isa piston I2I which is free to reciprocate on shaft II9 between a pin I22 and a, valve member I23 both fixedly attached to shaft II9. Valve member I23 is in the form of a collar having an annular sealing portion I24 which serves, when pressed against piston I2I, to close an axial passage I25 in the latter. Flow of the damping fluid impelled by piston I2! is through a pipe I26 paralleling cylinder H8 and connecting the ends thereof through ports I21 and I28. In the fluid circuit I21, I26, I20, thus described, are disposed needle valves I29 and I30, the setting of which determines the degree of damping provided by stabilizer II'I. Fluid passage I25 in piston I2I, mentioned hereinbefore, cooperates with collar I23 to provide in effect a unidirectional check valve, whereby stabilizer II'I acts as a damper during bit-advancing movement of shaft II9 but is rendered ineffective during bitwithdrawing movement of shaft II9 by the free passage of fluid through passage I25.

Stabilizer II! is coupled to driving means through an arm I3I suitably mounted on rack 24 (Figures '7 and 12). Physically, arm I3I, with its bifurcated end I32, is identical to arm 96, which serves to couple driving means I6 to valve 23 as hereinbefore described. The symmetry of these members with respect to rack 24 is evident from Figure 7. This symmetry extends to the adjustability of tube I20 on shaft I IS, the functions of which correspond'exactly to those of tube I93 and shaft 'IIi, respectively.

It will be noted that collar I33 mounted adjustably on shaft H9, is shown spaced from collar I34, also mounted adjustably on shaft II9, thus allowing a region of lost motion in which stabilizer II'I is not coupled to driving means I6. The purpose of this lost motion is to provide means whereby the initial portion of the bitadvancing movement of driving means I6 is free; from the damping effect of the viscous fiuid in cylinder II8. In this way rapid progression of bit I3 to its entrance into work 29 may be provided, at which point arm I3I encounters collar I33 and thereby couples stabilizer II! to driving means I6. I

A brief description of the operation of stabilizer I II will serve to clarify the functions of the parts thus far described. With piston 36 advancing by virtue of pressure applied thereto through valve 23, rack 24 rapidly progresses until arm I3I contacts collar I33 and, through shaft II9, pulls collar I23 firmly against piston I2I. vAt

this point further progression of'piston 36 is resisted by the viscous fluid in cylinder ,8, which must be forced out of cylinder I I8 through port I27, needle valve I29, pipe I29, needle valve I30, and port I28, back into cylinder H8. The viscous nature of the fluid in cylinder II-S appreciably impedes further movement of piston 36 so that continued advancement thereof proceeds at a much slower rate than previously. Such retarded and stabilized progression continues until valve 23 is operated, either by mechanical control (arm 96, shaft 13) or electrical control (solenoid 93, sleeve l9), or manually (knob 88, shaft 16), to the bit-withdrawing position, whereupon pressure on piston 36 is reversed, reversing its movement.

The bit-withdrawing movement of piston 35 proceeds rapidly, in the course of which arm I3I encounters collar I34 and pushes shaft II9 back to its starting position. During the bit-withdrawing motion of shaft H9, little impedance is encountered because of the opening of passage I25 occurring upon Withdrawal of collar I23 from engagement with piston I2I.

The stabilizing character of stabilizer II! is attributable to the velocity responsive nature of the impedance offered to forward movement of shaft I19. That is to say, with shaft H9 being drawn forward slowly, the impedance offered by stabilizer II! is of a relatively nominal' value as determined by the setting of needle valves I29 and I30. Should, however, rack 24 tend to accelerate, the impedance offered by stabilizer II'I would rapidly increase with increasing velocity, tending in this manner to stabilize the velocity of movement of driving means I6 at a value dependent largely on the setting of needle valves I29 and I30, and on the air pressure in cylinder II as determined. by a regulator I35 interposed in line 22 between source 2I and valve 23.

The importance of this function will be readily seen by hypothesizin that work 28 consists of a member which will offer varying resistance as bit I3 advances. Assuming that work 28 initially offers great impedance to advancement of bit I3, piston 36 advances slowly by virtue of the impedance offered by the work and the greater impedance offered by stabilizer III. When a portion of lowered impedance is encountered in work 28, the tendency of bit I3 to accelerate is resisted by the viscous fluid in stabilizer II'I. Conversely, when a portion of increased impedance is encountered in work 28, the tendency of bit I3 to decelerate is compensated by decreased impedance in stabilizer II'I, resulting from lowering velocity. Inasmuch as the impedance offered by stabilizer II'I may be made large in proportion to the maximum impedance to be encountered in work 28, the stabilized velocity of advancement of piston 36 may be made substantially independent of the character of work 28. The integral, unitary fabrication of power cylinder I! and stabilizer cylinder III! simplified greatly the problem of coupling stabilizer shaft II9 to rack 24.

Electrical control of valve 23 through solenoid 93, and the control of a complete work cycle made possible thereby will now be described.

Referring to Figure 13, the electrical control circuit is shown, including the above described lever IIO actuated by plunger I09 of solenoid 93, which is preferably of the dual-actuation type having coils I36 and I37. Energization of coil I35 pushes out plunger I03 (toward the left); energization of coil I3'I retracts plunger I09 (toward the right). Energizing current for coils I35 and I3! is applied through a double throw switch I38 actuated by an arm I39 pivoted at I40 and operated by pressure against roller I-II in a manner to be described hereinafter in connection with the intermittent bit-withdrawal feature of this invention. Energization of coil I35 causes plunger I09 to push lever IIO, thereby sliding sleeve I9 to the right to operate valve 23 to the bit-advancing position (Figure 8); energization of coil I3! causes plunger I09 to pull lever IIEl, thereby sliding sleeve 19 to the left to operate valve 23 to the bit-withdrawing position (Figure 10). Energy is applied to arm I39 through front contact I42 of a relay I43 energized from a suitable source ofpower I44. Coil I45 of relay I43 is customarily energized through push button start switch I46. Relay Hi3 holds itself closed through a circuit including normally closed stop switch I41 and limit switch I48, the latter to be described'more particularly in connection with Figures 1%, 15, and 16.

Inasmuch as a continuous drilling operation not only produces long shavings which, when metal, are dangerous to personnel, but also causes the bit to heat dangerously; it is desirable to intermittently withdraw bit I3 from work 28 for brief intervals. To this end the circuit of Figure 13 includes an electric motor I49 energized through front contact I42 of relay I43 and driving a disc I50 onwhich are mounted a plurality of cams I5I pivoted at I52 and adjustable in slots I53. Clockwise rotation of disc I50 by motor I49 causes cams I5I to intermittently and momentarily bear against roller I iI, shifting arm I39 and switching double throw switch I38 from its position energizing coil I 35 to the position wherein coil I31 is energized. In this manner valve 23 is maintained for the greater portion of the time in bit-advancing position (coil I36 energized) but is momentarily reversed to bit-withdrawing position as cams I5! intermittently engage roller I il and actuate switch I38 to energize coil I37. The percentage time during which bit I3 is being withdrawn in this intermittent operation is determined by the adjustment of cams I5I in slots I53. For most operations it is satisfactory that bit I3 be lifted only slightly before re-insertion in work 28 and in this case cams I5I are adjusted for only short contact with roller I4I. The rate at which the momentary withdrawing of bit I3 occurs is determined by the speed of motor I43 which may be made variable at will. Electrical control without the intermittent bit-withdrawal above described is effected simply by opening switch III! in the circuit of motor I49.

During electric control of the drilling operation, master switch IE4 is closed. Momentary closing of start button switch I46 energizes relay I43 which holds itself closed through circuit I47, I43. The energy thus applied to switch I39 energizes coil I33, whereupon plunger I09 pushes lever IIfi to the bit-advancing position as illustrated in Figure 7. Simultaneously rotation of disc I59 is begun. Piston 36 advances steadily until one of the cams I5I bears against roller Hi! causing switch I33 to energize coil I3'I. This abruptly shifts valve 23 to the bit-withdrawing position, and piston 35 reverses its motion withdrawing bit !3 from work 28. When roller I iI drops from cam I5 I, switch I39 returns to the bite. advancing position, energizing coil I36, which position it retains until another cam I5! actuates roller I4 I. In this manner, drilled shavings being forced from work 28 are broken into short from arm 96) limit switch I48 (Figures 14, 15 and 16) is opened, de-energizing relay I43. De-energization of relay I43 causes energization of coil I31 through back contact I55 and circuit I56, actuating sleeve 19 and operating valve 23 .to the bit-withdrawing position.

In parallel with push-button start switch I46 may be connected a foot switch I51 which is preferably of the double throw type, whereby through selective use of switches I58 or I59 the circuit may be either opened or closed upon pressing on foot switch I51.

Limit switch I46, described above in connection with the electrical circuit of Figure 13 will now be described in detail with reference to Fi ures 14, 15 and 16.

Actuation of limit switch I48 is preferably effected through shaft (Figure 15) journaled in housing 26 and in which gears 56 and 54 are mounted. On the side of housing 26 opposite control handles I5 and 69 is mounted a small housing I66, in the outer wall I6I of which is journaled, coaxially with shaft 5I, a shaft I62. Mounted on the inner end of shaft I62 is a microswitch I63 having a reciprocable pin I64 extending therefrom. Inward movement of pin I64 serves to open microswitch I63. Pin I64 is spaced radially from the rotative axis of microswitch I63 a distance equal to the radial displacement of a small button I 65 in the end of shaft 5| (Figures 15 and 16). It will thus be seen that when shafts BI and I62 are in a predetermined angular relation, and only when they are in this angular relation, pin I64 will be depressed by button I65, thereby opening microswitch I63.

The angular position of microswitch I63 is controlled by the setting given a radial finger I66 mounted on the outer end of shaft I62. Continuous, uni-directional rotation of shaft I62 is made possible through the employment of a conventional brush and slip ring assembly shown at I61 by which connections to microswitch I63 are carried externally of housing I66.

In operation, finger I66 is given a desired angular setting as indicated with reference to a dial I68 on wall I6I. This determines the angular spacing betwen pin I64 of microswitch I63 and button I65 on shaft 5I. When shaft :5I has rotated through this angular spacing, button I65 depresses pin I64, opening microswitch I63 and de-energizing relay I43 (Figure 13). In this manner the limiting bit-advanced position is determined through the electrical control rather than through the mechanical control of arm 96 acting on collar I6I as shown in Figure 7.

Use and operation of the powered-driving apparatus for controlling the longitudinal position of bit I3 will now be described in detail.

The apparatus is applied to drill press I6 with driving means I6 (Figure 1) anchored to standard IIb-y cooperative clamp members 29 and3l (Figure 2). A bushing 56 (Figures 3 and ,4) of proper internal diameter to fit snugly on shaft I4 of drill press I6 is selected and. anchored to shaft I4 by set screw I59. Sleeve 6| is slipped over bushing 58 and anchored thereto by set 14 screw 66,thereby providing support for housing 26 of the apparatus. In this manner each end of the apparatus, I6 and 26', is supported on drill press I6. Any slight discrepancy in the mounting is absorbed in the pliant mounting means at ends 46 and of rods 33 and 35, respectively.

With the apparatus securely mounted to drill press I0, three types of operation are possible: manual, mechanically controlled power, or electrically controlled power.

For manual operation, it is necessary only to juxtapose handles I5 and 69 from their positions shown in Figures 4, 5 and 6, thus causing balls III to seat in recesses I4. This relieves pressure on sleeve 61 and allows shaft I4 to be manually turned by juxtaposed actuation of handles I5 and 69. Sleeve 61 and the remainder of the power driven assembly are effectually de-coupled from shaft I4 during this operation, and the operator controls press I6 as though the apparatus of this invention were not present.

Powered operation, mechanically controlled, will now be described. Switch I54 (Figure 13) is opened, thereby allowing plunger I69 (Figures 8 and 16) to reciprocate loosely in solenoid 93 and ofier no impedance to free oscillation of lever I I6 about shaft III. Under this condition sleeve I9 is functionally an integral part of shaft 76, being retained relatively fixedly thereon by springs 89 and 96.

It will be assumed that a sufficient number of identical operations are to be performed to justify setting up the power speed feature eifectuated through employment of stabilizer I I1. Clutch 56 (Figure 4) is engaged by separating handles I5 and 69, causing sleeve 61 and collar 68 to be frictionally clamped between shoulder 62 and collar 65. Valve 23 is actuated to the bit-advancing position by pushing on knob 68 (Figure 8). This done, bit I3 advances relatively rapidly passing through guide 21, the speed of advance being controlled by regulator I35.

Knob I69 (Figure 12) is turned, advancing collar I33 until it abuts arm I3I, establishing coupling between stabilizer II! and driving means I6 just before the bit engages work 28. Further bit-advancing movement of rack 24 quickly takes up the slack between piston I2I and collar I23, and from then on advancement of rack 24 is stabilized, o-r dampened, by stabilizer I I1. Thus the bit I3 penetrates work 28 relatively slowly, the advancement thereof being impeded and stabilized by stabilizer III.

When bit I3 has advanced far enough into work 28, for example after passing through work 26, knob 88 is turned, advancing disc 96 (Fig-' beneath bit guide 21 (Figure 1). By means of.

knob .83 shaft 16 is pushed in, actuating valve 23 to the bit-advancing position (Figure 8), applying air through pipe 22, inlet port 8|, axial groove 84. axial groove 85, outlet port 63, into cylinder II, where it pushes against piston 36. Relatively rapid, unimpeded advance of rack 24, and consequent advancement of bit I3, then takes place until arm I3I (Figure 12) abuts collar I33 and begins to push shaft H9 causing collar I23 to close passage "I25 in piston IZI. This point having been predetermined" (as i1- lustrated above) as the point at which bit I3 enters work 23, the actual drilling operation is carried on under the stabilizing influence of stabilizer I I I. That is to say, rack 24 being coupled through arm I3I to shaft N9 of stabilizer 'II'I, advancement of rack 24 is impeded and stabilized by the damping action of piston IZI "being pulled forward in cylinder H8. The degree of damping, or stabilizing, is determined by the setting of needle valves His and I39, which control the external flow of viscous damping fluid from one end of cylinder H8 to the other through pipe I26.

During the advance of piston 36, exhaust air emerges from cylinder I? through ports 82 and 86, and valve 54, into pipe 2%, from which it exhausts to the atmosphere around bit I3, there'- by cooling the bit and dispersing drilled-out shavings which have been lifted to the surface of work 28 by bit I3.

Stabilized advance of bit I3 proceeds until the predetermined limit is reached. At this point, arm 96 (Figure 8) abuts disc 99 and compresses spring IIIIE suificiently to pull shaft IE to the bit-withdrawing position, i. e., to the left, overcoming the restraining action of pin IIl'I. By virtue of the energy stored in spring W9, shaft 76 is moved abruptly and completely from its extreme right hand position (bit-advancing) to its extreme left hand position (bit-withdrawing). When this occurs air pressure formerly applied through port 83 to advance piston 36 is applied through inlet port 8I, groove 84, and port 82 to the other side of piston 36 (Figure 10) thereby commencing withdrawal of bit I3.

During bit-withdrawal movement of piston 36, exhaust air passes through ports 83 and 81 and needle valve 95 into pipe 26, thereby continuing the shaving dispersing action in guide 21. Bit-withdrawal movement of rack 24 causes, in effect, de-coupling of stabilizer II? from driving means l6 (Figure 12), by virtue, of the departure of arm I3! from collar I33 as rack 24 withdraws. Upon abutment of arm I3I against collar I34, shaft H9 is returned to its starting position, this operation being undamped because of the opening of passage I25 through withdrawal of collar I23 from piston I2I. When pis ton 36 (Figure 8) has reached end wall I9 of cylinder I'I, driving means It has returned to its original position, being held there by the pressure of air against the left hand side of piston 3t.

Work piece 28 may then be removed and another, identical operation performed by placing another Work piece 28 beneath guide 21 and pushing in on knob 88 as described above.

For situations where repetitive identical work operations are not to be performed, it may be desirable to manually advance bit I3 to the surface of work 23 and allow powered driving means It to assume control at that point. For this operation, handles I5 and 69 are juxtaposed, thereby disengaging clutch 56 and de-coupling driving means IE from bit I3. The two handles, I5 and 69, are then manually turned until bit I3 touches the surface of work 23. The handles are then angularly separated, causing engagement of clutch 5S; and knob 88 is pushed in, instituting powered advancement of bit I3. Automatic reversal of bit It is accomplished through actuation of valve 23 by arm 96 in the manner hereto- 1'6 fore described and at the setting predetermined as described above.

For the partially manual-partially powered operation described above, stabilizer III may be employed or not as desired, or alternatively may be coupled to driving means It at any point in the movement of bit I3. If it is desired to employ stabilizer I I! during the entire powered advance of bit I3, knob IE9 is turned until arm I3I is clamped between collars I33 and I34. With this setting, stabilizer II! is continuously coupled to driving means It, there being no lost motion connection between arm ISI and shaft IIQ.

Powered operation, electrically controlled, will now be described.

Knob 88 is turned so that disc as is withdrawn completely from the travel span of arm ea. This removes any possibility of mechanical reversal of valve 23 by arm $5, leaving that function to limit switch I48.

Stabilizer II? is employed in the same manner as described in connection with mechanical control, and may or may not be coupled to driving means I5, as desired.

As in the case of mechanical control of driving means I5, described above, it is advisable to employ the electrical control only when a reasonably large number of identical operations are to be performed by bit I3.

To set the electrical control for the predetermined desired operation, swltch I55 (Figure 13) is closed, energizing coil 53? of solenoid 93 through back contact I 55 of relay I43. This moves lever III! to the position shown in Figure 10 and causes complete withdrawal of piston 38, and hence of bit I3, if not already completely withdrawn. One of the switches I it or I 51' is momentarily closed, energizing coil I 35 of relay I43 which holds itself closed through the circuit including front contact I42 and switches I4! and I 18. Closing of contact I52 allows power to be applied to coil I35 of solenoid 93 through switch I38, thereby actuating valve 23 to the bit-advancing position (Figure 7). As bit I3 advances, coupling of stabilizer I I? to rack 24 is accomplished in the same manner as described above in connection with mechanical control of powered operation. When bit I3 has penetrated the desired depth in sample work piece 28, finger I of switch I 38 (Figure 15) is manually rotated until pin I65 engages button I55, which engagement opens microswitch m3, deenergizi'ng relay I 43, back contact I55 of which causes energization of coil I3? of solenoid 33, thus initiating withdrawal of 'bit I3.

The settings of stabilizer coupling knob I39 and of limit switch I48 having been thus properly determined, automatic, repetitive working of similar work pieces 23 is accomplished as fol ows:

'A work piece 23 is inserted under bit guide 21, and switch I45 is momentarily closed. The resulting energization of relay M3 causes energization of motor M8,,which rotates disc I51 For the greater portion of rotation of disc I5 3, switch arm I39 is in position energizing coil I36 of solenoid 93., This rotates lever IIIi clockwise (Figure 8) in turn pushing sleeve is to the right against the bias of spring Bil. As the right hand edge of groove H5 in sleeve "IS passes the left hand edge of notch H5 in shaft air from pipe 22 flows through inlet port SI, slot 84, ground groove I I5, into notch I I5, and thence into the right hand portion of cylinder I5 where presses against piston I8. At this point the air pressure assumes control of the-actuation of .valve 23 and pushes piston IStothe right, the valve quickly assuming. the position illustrated in Figure 8. It is thus seen that by providing sleeve. .19. in valve 23, low power actuation (through solenoid 93) sets in motion a more powerful force (represented by the compressed air) which completes actuation of valve 23.

With valve 23 in the position shown in Figure 8, air from pipe 22 flows through inlet port 8|, slot 84 in sleeve I9, groove 85 in valve body 88, and thence into the right hand portion of cylinder 15. From there it enters driving cylinder ll through port 83 and pushes against piston 36, thereby initiating bit-advancing movement of driving means IS. i r

Bit-advancing movement thus commenced proceeds relatively rapidly until arm I3I (Figure 12) engages collar I33, thereby coupling stabilizer I I! to driving means I6, as fully described above in connection with mechanical control. Stabilized, or damped, bit advancement continues until shaft (Figures 5 and 4) has turned sufliciently to bring button 155 into engagement with pin I64 on micro-switch Hi3. At'this point switching means ms (Figures 13 and 15) is opened, .de-energizing coil i 35, and opening relay I43. This transfers energization from coil I36 of solenoid 93 tocoil 13?, thereby rotating lever III) (Figures 9 and counterclockwise. As sleeve I9 is pushed-to the left by lever no (Figure 9), the left hand edge of groove H6 overlaps the right hand edge of notch l is in shaft i6. At this point air pressure from source 2! assumes control by entering cylinder I5 through port SI, slot 84, groove H6, and notch I I4, where it bears against piston l? pushing shaft 'ifi to its extreme left position as shown in Figure 10.

Air is thus cut off from port 83 and admitted to port 82, reversing air pressure on piston 36 and instituting bit-withdrawal movement of driving means IE. Withdrawal movement continues until piston 36 is stopped by wall I9 of cylinder ll.

Meantime, piston 36 has been momentarily and intermittently jerked from work 28 by the action of disc I56, as follows: During electrical control of bit-advancing movement, it will be recalled that front contact I42 of relay I43 is energized. This energizes motor I49 causing disc I553 to rotate at a substantially constant speed. During the major portion of each revolution of disc I56 roller lei on arm I39 is unrestrained, causing the bias inherent in arm I39 to effect electrical contact with the left hand side of switch I38, thereby energizing coil I39 (the bitadvancing coil) of solenoid 93.

As disc I59 rotates, one of the cams i5! is brought into contact with roller MI, causing switch arm !39 to transfer energization from the left to the right in switch I38, thereby energizing coil I31 (the bit-withdrawing coil) of solenoid Sit. Thus, for the duration of engagement between roller I l! and cam IEI, valve 23 is thrown to the bit-withdrawing position (Figure 10).

Inasmuch as roller MI engages cam lei only during a minor portion of a complete revolution of disc Hit, it will be seen that the action produced is that of normally advancing bit I3, but intermittently and momentarily withdrawing it in its progress through work 28. This action breaks up the shavings drilled out by bit I3, which results in a cooler running bit due to less 18 friction created by the short chips, allowing it to cool during this operation; and the shorter chips. do; notform as neat an obstruction to cutting oilsand thereby allow more oil to enter the work. i

Should operation without the intermittent withdrawal feature be desired, switch I10 is opened, care being taken to leave roller I4I free .of cams [5| so that switch I38 is thrown to energize coil I36. I c a R l. Fluid actuated apparatus for a machine having a movable member, comprising: a power cylinder havin a port near each end thereof; a, piston movable in said cylinder; a shaft attached to said piston, extending outside said cylinder, and operatively arranged to actuate said movablermember; .a valve cylinder having an outlet port near each end thereof as ,Well as an exhaust port, and an inlet port, each said outlet port being connected respectively to a corresponding port of said power cylinder, said .inlet port being disposed intermediate said out- .let ports, and being adapted for connection with a source of fluid under pressure; a valve piston operable in said valve cylinder to control passage. of fluid from said inlet port to said outlet ports respectively, and between said outlet ports and said exhaust ports respectively; a valve shaft attached to said valve piston, and extending outside said valve cylinder to a region near said machine for operation by the shaft attached to said piston; a valve sleeve slidable in said valve cylinder to control application of fluid from said inlet port to said piston for effecting operation of said piston in said valve cylinder; and means eifectiveto slide said sleeve in said valve cylinder.

2. Fluid actuated apparatus for a machine having a movable member, comprising: a power cylinder having a port near each end thereof; a piston movable in said cylinder; a shaft attached to said piston, extending outside said cylinder, and operatively arranged to actuate said movable member; a valve cylinder having an outlet port near each end thereof as well as an exhaust port, and an inlet port, each of said outlet ports being connected respectively to a corresponding port of said power cylinder, said inlet port being disposed intermediate said outlet ports, and being adapted for connection with a source of fluid under pressure; a valve piston operable in said valve cylinder to control passage of fluid from said inlet port to said outlet ports respectively, and between said outlet ports and said exhaust ports respectively; a valve shaft attached to said valve piston, and extending outside said valve cylinder for operation by the shaft attached to said piston; and auxiliary valve means in said valve cylinder eifective to control application of fluid to said valve piston for moving said piston.

3. A valve comprising a cylinder having an outlet port, an inlet port spaced longitudinally with respect to said outlet port, and an axial passage in the inner surface of said cylinder, located intermediate said ports; a piston fitting transversely in said cylinder and slideable axially therein; a shaft attached to said piston and extending axially outside said cylinder, a sleeve disposed around said shaft in said cylinder and generally opposite said inlet port, slidable longitudinally with respect to said cylinder and to said shaft, and having a passage therein effective to register with said axial passage; and means ef- 19 fective to reciprocate said sleeve within said cylinder.

4. A valve comprising a cylinder having outlet port near each end thereof, an inlet port intermediate said outlet ports, and an axial passage in the inner surface of said cylinder, located intermediate said outlet ports; an axial shaft in said cylinder-extending outside thereof; pistons mounted on said shaft, one near each outlet port; a sleeve disposed around said shaft in said cylinder and generally opposite said inlet port,

slidable longitudinally with respect to said cylpiston movable in said cylinder; a shaft attached to said piston, extending outside said cylinder, and operatively arranged to actuate said movable member; a valve cylinder having an outletv port near each end thereof as well as an exhaust port, and an inlet port, each of said outlet ports being connected respectively to a corresponding port of said power cylinder, said inlet port being disposed intermediate said outlet ports, and being adapted for connection with a source. of fluid under pressure; a valve piston operable. in said valve cylinder to control passage of fluid from said inlet port to said outlet ports respectivelsnand between said outlet ports andsaid exhaust ports respectively; a-valve sleeve slidablein said valve cylinder to control application of fluid from said 20 inlet port to said valve piston for effectingop eration of said piston in said valve cylinder; and means effective to slide said sleeve in'said valve cylinder.

DON HEYER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 129,269 Clayton July 16, 1872 657,185 Taylor Sept... 4, 1900 830,721. King Sept. 11,1906

1,007,377 Nielson Oct-31, 1911 1,363,333. Lower,: Dec. 28, 1920 1,398,338 Mirrielees Nov; 29, 1921 1,422,767 Keast July 11, 1922 1,445,127 Buckman Feb. 13, 1923 1,665,815 Johanson Jan. 10, 1928 1,667,138 Barks Apr. 24, 1928 1,680,091 Desautels Aug. 7, 1928 1,700,668: Damerell Jan. 29, 1929 1,700,956 Smith" Feb. 5, 1929 1,787,782 Galloway Jan. 6, 1931 1,812,533 Hunt ,June 30,1931 1,816,829 Deleeuw -Aug. 4, 1931 1,905,133 Bishop Apr. 25, 1933 1,998,873 Kingsbury Apr. 23, 1935 2,134,072- Christensen Oct. 25, 1938 2,212,871 Wood Aug. 27, 1940 2,253,617 Griffith: Aug. 26, 1941 2,392,074 Wasson Jan. 1, 1946 2,418,841 Karwei-t Apr. 15, 1947 2,430,019 Jenkins Nov. 4, 1947 2,449,639 Cannon Sept. 21, 1948

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