US3202060A

US3202060A - Fluid power cylinder

Info

Publication number: US3202060A
Application number: US337699A
Authority: US
Inventors: Grotness Gunnar
Original assignee: PNEUMATIC HYDRAULIC DEV CO Inc
Current assignee: PNEUMATIC HYDRAULIC DEV CO Inc
Priority date: 1963-12-30
Filing date: 1963-12-30
Publication date: 1965-08-24
Anticipated expiration: 1982-08-24
Also published as: GB1036498A; DE1909503U

Description

Aug. 24, 1965 G. GRoTNEss FLUID POWER CYLINDER 3 Sheets-Sheet 1 Original Filed NOV. 20, 1961 Aug 24, 1965 G. GROTNESS FLUID POWER CYLINDER 3 Sheets-Sheet 2 Original Filed Nov. 2O 1961 Pfg. 7

Aug. 24, 1965 G. GRoTNEss FLUID POWER CYLINDER 5 Sheets-Sheet 5 Original Filed Nov. 2O 1961 J M M B INVENTOR. Gunnar' r'ae ss BY M] United States Patent O M' 3,202,060 FLUID POWERCYLINDER Gunnar Grotness, Fort Wayne,.1nd., assignor t Pneumatic-Hydraulic `Development Co., Inc., Fort Wayne,

Ind., a corporation of Indiana Continuation of application Ser. No. 153,471, Nov. 20, 196'1. This-application Dec. 30,1963, Ser. No. 337,699

This is a continuation of application Serial N0. 153,- 471, now abandoned, filed November 20, 1961.

The' present invention relates to afluid power cylinder and more particularly to a power cylinder with selfcontained flow or speed' control elements which are incorporated intdan integrated, interchangeable and compact. assemblyto' provide adjustable, constant control of piston velocity. This invention also relates to various fluid power cylinder designs including single rod end and double rod end types when operated either single or double acting whereby piston velocity is governed throughout the entire portion of the cylinder stroke whether it be push or pull.

Fluid power cylinders operated" by gaseous or other fluid media are variously controlled in the respects of both power and velocity of operation. Such iiuidA power applications conventionallyinclude the usual power cylinder'in conjunction or combination with individual supplylines and controls separately connectedA thereto as individual accessories. Being so constructed, the space occupied by the complete system is not only that required by the power cylinder itself, but also the space required byjthe individual, separate controls which are usually in the form of valves of various design.

Systems in which the power cylinder havingthe usual rod andcap ends is connected to externally locatedspeed controls or valves have two pressure uid lines connected to the rod and cap ends, respectively, and atreversing control valve is connected to the dist-al endsv of the pressure lines. A suitable source of pressure fluid may be connected to this valve. `In thisprior art arrangement, eachV line is` provided with a speed control valve assembly connected in `series therewith. Each assembly has physical size which not only requires a certain amount of space but can add to the length of the pressure lines. Additionally, these valve assemblies, being external to the power cylinder, are necessarily spaced therefrom, such that the length ofthe pressure lines providing for the connections between the power cylinder and the valve assemblies present an enclosed `volume which is in series with the power cylinder itself. In other words, the volurne of liuid. to'which the piston is subjected andin which it `must work is not only that enclosed `by the power cylinder itself, `but also that existing i'n the pressure lines between the power cylinder and the speed control valve assemblies. i

As will appear from the following discussion, this prior art system `presents problems which are intolerable in certain situations. The present invention overcomes these problems.

f Inpowercylinders of the character contemplated `by this invention, the features of `(1)7piston`velocity, (2) power applied to the `piston and (3) compressibility of theifluid medium against whichand in which the piston operates are of direct concern. With respect to piston velocity, and keeping in mind `the foregoing prior art system, control thereof is governed by resistance to fluid flow, or, in other words, pressure drop, across an orilice having aA size determinedfbya needle valve. This orifice and needle valve combination is incorporated in the previously mentioned speed control valve assembly which is mounted externally to the power cylinder. l Pre- CII 35,262,660 Patented Aug. `24., 1965 ice cise control of this` piston velocity is not possible inthis prior art arrangement, since the volume of the compressible, gaseous medium (such as air) against which the piston works is relatively large as previously explained. For small diameter or short stroke power cylinders, it is absolutely necessary that the compressible volume be reduced, toA an absolute minimumto provide eliicient, reliable control of the piston velocity. The present invention provides this. p

The present invention is unique for the reasons, among others, that `the (l) piston velocity is precisely controlled, (2) power applied to the piston is also closely controlled and rendered uniform, (3) the problems of compressibility have been overcome, and (4)` thespace occupied by Athe total system is much smaller thanlthat `of prior art systems. ijn theiaccomplishment of these features, speed and power control elements are integrated into the power cylinder itself, andmore particularly within the rod and cap ends thereof. The present invention makes this` possible by using blind port construction in the cap and' rod ends, respectively, whereby the volume of air or other fluid under pressure is limited to the content ofthe cylinder bore only and is isolated from the external pressure fluid lines.

This invention provides a self-contained unit wherein the control valve is integrated with the cylinder-piston assembly and is so arranged as not only to control the speed of operation but also to apply full power to the piston during the entire stroke thereof.

It is therefore an object of this invention to `provide a power cylinder construction whereinV control valve mechanism is integrated therewith and is so `arranged as not only to govern thevelocity of the piston through the CAB full stroke but also to apply uniformly full power to the piston throughout every incremental portion of the stroke. It is another object of this invention to provide a liuid power cylinder so constructed as to provide for precise control of piston velocity, the application of uniform powernor pressure to the piston, the reduction of compressibility effects ofthe `fluid in which the piston must operate, and the rendering of a total system more cornpact.

It is another object of this invention to provide` maximum ratio of bearing length for the piston rod when the bearing is located in `the rod `end of the cylinder while at the same time accomplishing the features'of precise control of piston velocity, uniform application of pressure to the piston, provision of minimal coinpressibility of the fluid in which the piston acts and the like. This permits the utilization of the entire thickness of the rod end of the power cylinder for use as the rod bearing. Y

`It is still another object of `this invention to provide a fluid power cylinder of such design that overcomes the foregoing mentioned problems, this design beingthe optimum in compactness. l

lt is an object of this invention to provide a selfcontained power unit `wherein the controlvalve `.is integrated `into the cylinder-piston assembly.

It is another object of this invention to provide a control valve assembly integrated with its power cylinder whereby full power is applied tothe pistonfor its entire stroke.`

It is still another object of thisinvention to provide a uniquely constructed valve element which` cannot be accidentally removed from `its assembly during adjustment.

It is yet another object to provide a valve element incorporating a `rubber-like seal whereby the seal performs the twofold function of not only preventing leakage but also of locking the control valve against accidental adjustment.

A further object is to provide a power cylinder of compact design which is simple, economical and reliable in operation.

Other objects will become apparent as the description proceeds.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction 'withv'the accompanying drawings, wherein:

y FlG. l is a top plan View of one embodiment of this invention;

FG. 2 is an end view thereof;

FlG. 3 is a fragmentary sectional illustration showing the cap end of the cylinder taken substantially along section line 3 3 of FIG. 2;

FIG. 4 is a cross-section taken substantially along section line 4 4 of FIG. l;

FIG. 5 is `an enlarged side View of the needle valve assembly used in the arrangement of the preceding figures;

FIG. 6 is an illustration of a typical system into which the power cylinder of the preceding figures is connected;

FiGS. 7 and 8 are diagrammatic illustrations of the systems of FIG. 6;

FIG. 9 is an axial sectional view of the head block on the rod end of the cylinder taken at right angles to that of FIG. 3; and

FIG. 10 is an axial, fragmentary sectional view, similar to Fl'G.V 3, illustrating in enlarged detail both the rod and cap ends of the cylinder.

' Referring to the drawings, and more particularly to FiG. 1 thereof, a power cylinder which may be either pneumatically or hydraulically operated comprises a cylinder tlvwhich receives for reciprocation a conventional piston 13. The opposite ends of the cylinder 1t) are closed by means of two

head blocks

12 and 14, respectively, and a piston rod 16 is secured coaxially to the piston 13 and reciprocally projects through the head block 14. chambers 13 and 2) such that iiuid pressure admitted to chamber 13 will force the piston 13 toward the right while fluid pressure admitted to the chamber 20 will force the piston 13 toward the left.

The two head blocks 12 and 14am substantially identically constructed except for the fact that the block 14 is provided with centrally disposed aperture 22 for reciprocally receiving the piston rod 16.

Blocks

12, 14 can be made having a variety of thicknesses; this fact is illustrated in FIGS. 1, 6 and 1G by showing block 14 thicker than block 12, block 12 thicker than block 14, and

blocks

12, 14 of equal thickness, respectively. Thus, a description of one

block

12, 14 with respect to the control valves and the like will suihce for both.

The

head blocks

12 and 14 are securely clamped to the'opposite ends, respectively, of the cylinder 1l) by means of four elongated rods 24 which are threaded into the rectangular block 14 adjacent the corners thereof as shown and entered into apertures in the corners of the head block 14to receive ordinary screws 26 for drawingf the `two

head blocks

12 and 14 toward each other and into sealing ,engagement with the opposite ends of the cylinder lil.

The head block 12 will now be described. lt is first of all provided with a bore or blind port 28 through one side as shown which extends about half-way through the block 12. Then extending inwardly from the opposite sides 3@ and' 32, respectively, of the block 12, are two

bores

34 and 36 which in one embodiment of the invcntion are substantially identical in size and shape. As a matter of fact, as shown in FlGS. 2 and 3, these

bores

34 and 36 are formed about a common axis and extend inwardly toward each other until they intersect the lower end of the first bore 23.

. The

bores

34 and 36 are of stepped diameter coniigura- The piston 1.3 divides the cylinder into two v tion, the bore 34 having a larger diameter portion 3S which joins a smaller diameter portion in a valve seat 42. Similarly, the bore 36 is provided with a larger diameter portion 44 and a smaller diameter portion 46 which are joined together to provide a valve seat at 48. As already explained, these two

bores

34 and 36 are substantially identical in size and shape for reasons which will become apparent from the following description.

In the bore 34 the outer end is threaded at 50 to receive a retaining nut 52 provided with a socket 54 in its inner end. A ball check valve 56 is yieldably urged into seating engagement with the valve seat 42 by means of a helical compression spring 5S which enters and is retained by the socket 54. larger diameter bore portion 38 with the cylinder charnber 18 as shown. The Valve 56 is therefore interposed between the passage 60 and the bore 28.

The outer end of the bore 36 is threaded at 62 and receives a retaining nut 64. This retaining nut is provided with a coaxial, threaded opening 6e which receives the threaded end 63 of a needle valve 70. This needle valve is provided at its inner end with an enlarged, frusto-conically shaped valve tip 72 which is enterable into the smaller diameter bore portion 46 and engageable with the valve seat 4S to seal off any iiow of fluid through the valve portion 46.

As shown more clearly in FIG. 5, the needle valve 'iti is provided with an integral annular collar 74 intermediate tne Valve tip 72 and threaded end 655, the diameter of this collar 74 being substantially equal to the diameter of the bore portion 44.

Mounted on the needle valve '70 between the valve tip F2 and the collar 74 is a rubber O-ring seal 76, this seal frictionally engaging the shank of the needle valve 70 itself and also being of such outer diameter as to frictionally engage the inner wall of the bore portion 44. Thus, as viewed in FlG. 3, the needle valve 7G is restrained against rotation` by virtue of the fric-V tional grip afforded by the O-ring seal 76, this preventing the needle valve from being accidentally loosened or adjusted in the retaining nut 64.

Through the use of the O-ring seal in this manner, it is not necessary to use a locknut on the outer end of the thread 63 which would normally bear against the retaining nut 64.

A passage 7S connects the bore portion 44 to the cylinder chamber 18. Thus, the bore portion 46 is interposed between the cylinder chamber 18 and the first bore 2S.

As will now be clearly understood, the needle valve 7@ may be adjusted by virtue of its threaded connection with the retaining nut 64 to vary the size of the opening of the bore portion 46 into the larger diameter bore portion 44. By this means, the fluid which passes from the cylinder chamber 13, through the passage 78, and eventually into the blind port 23 is metered. The O- ring seal 76 prevents leakage outwardly around the threads of either the nut 64 or the needle valve 7l?.l

Thus, far, the head block 12 has been described. As previously mentioned, the head block 14 is similarly constructed, and in this connection like numerals will indicate like parts (FlG. 4). With particular reference to FlG. 4, it will be noted that the bore or blind port titi which corresponds to the blind port 28 in block 12 is not quite as deep, such that two angular bore extensions S4 connect the bore Sil with the respective bore portions 4t) and 46. In all other respects, except for reciprocally receiving the piston rod 16, the construction of head ,block 14 is the same as that of head block 12.

With reference to the two bores 28 and Si), they are alike to the extent that they extend into the

respective blocks

12 and 14 from the sides thereof and are there-` fore closed at the inner ends. This particular bore con- A passage 6th connects theV blind port 28 and during another period of time uid l pressure will be admitted to the blind port 8i). By alternating the `.admission of fluid pressure tothese two blind ports, the piston 13 may be caused to reciprocate.

The

lines

86 and 88 are composed of conventional pipe,

elbows and couplings, and the valve 90 is of conventional design and preferably is manually operable to control the admission and exhausting fluid to the

chambers

18 and 20. `For one direction of valve 9i) operation, air, for example, under pressure is admitted to chamber 18 via `line 86 for forcing piston 13 toward the right as viewed in FIG. 46. Simultaneously, air is exhausted from chamber 20 via line 88 and the exhaust port 92 of valve 90. For the opposite "direction of valve 9) operation, the reverse flow of air is effected, air under pressure passing through line 88 into chamber 2t) for moving piston 16 leftwardly, and exhausted air flowing from chamber 18 through line 86 and out of exhaust port 92. The valve 90 may conventionally have a vertical position in which no air is admitted to or exhausted from the

chambers

18 and 20.

FIG. 8 is the diagrammatic equivalent of the system shown in FIG. 6.

In operation, the needle valve 70 is retracted from the valve seat 48 so as to provide communication between the bore 28 and the cylinder chamber 18. The same is true of the needle valve 70 in the head block 14 (FIG. 4). As a first cycle of operation, let it be assumed` that uid pressure is admitted to the bore 2S, and that uid in chamber 20 is exhausted from the bore 80. This fluid` pressure ows past the valve tip 72, the passage 78 and into the cylinder chamber 18. Also, this same fluidpressure also flows past the check valve 56 through the passage 60 and into the cylinder chamber 13. This drives the piston 13 toward the right as viewed in FIG. `1, causing the air in the chamber 20 to compress. As a consesequence, and now considering FIG. 4, the compressed air will attempt to pass out of the passages in block 14 which correspond to passages't) and 78 of the end'block 12. Since the ball check 56 is seated, the fluid, of course, cannot pass out of the bore portion 4t). However, by reason of the fact that the valve tip 72 (FIG. 4) is retracted from the seat e3, the air can exhaust through the passage 755, the bore portion 44, bore portion 46, boreextension 84 and outwardly of the bore 80. The speed at which the piston 13 approaches the head `block 14 can be governed by the size of the opening provided between the valve tip 72 (FIG. 4) and the seat 4S, and it may now be stated that this is the means for controlling the speed of operation `of the power cylinder.

Once the piston 13 has fully protracted `and abuts against the head block 14, the admission ofV pressure fluid-is reversed suc'n that pressure fluid is applied through the bore Si) and fluid is permitted toexhaust from the bore 28. The exact reverse performance results in the piston 12 retracting to its illustrated position up against the `head block 12, the valve tip 72. of FIG. 3 determining the speed at which the `piston retracts.

It will now be apparent that the speed or protraction and retraction, respectively, of the piston 12may bevaried to suit operational requirements. f

The speed of the power cylinder` is normally adjusted while the power cylinder is in operation and `is connected to its associated equipment. This, as explained previously, is accomplished by adjustment of the needle valves 70. lVithtluidA power applied tothe cylinder and the piston 12 reciprocating, each needle valve 70 is adjustedto the de-` sired position.

valve seatv48 is fully opened (FIG. 3). However, `should the needle valve be backed outwardly to its full extent, the collar 74Vwill be abutted against the inner end of the retaining nut 64, thereby preventing the needle valve from being fully withdrawn from the retaining nut 64. This is important for the reason that if the collar ,'74 were not presentthe needlevalve 76 couldbe withdrawn cornpletely from the retaining nut 64, thereby allowing` the escape of pressure iuid which is` introduced at thebore 28. This has been one difficulty experienced in the past with prior art needle valves, and'it has been found that' the escape of pressure fluid from the opening` 66 inthe retaining nut 64 is so violent that it is impossible to reinsert the needle valve into the `opening unless the entire system has been first shut down. Also, when the prior art' needle valves without the collar 74jhave been backed out to the point where the threads thereof lose engagement with: the retaining nut 64, the uid pressure blows the needle valve outwardly andv away,`whereby the needle valve usually becomes lost. This requires a completeV shutdown of the `system and replacement of the lost needle valve` by a different one. By using `the collar 74, the accidental removal of the `needle valve is obviously prevented.

As will' be noted by viewing FlG. 5, the fluid pressure acts against the O-ring seal in such a manner as to force` it against the collar 76 and to distend it against the shank of the needle valve as well as against the wall of the bore portion 4.4. This tends to tighten the needle valve against rotation,-thereby locking it in position. Since equipment with which the power cylinder is conventionally used vibrates considerably, it will be seen that this locking action prevents accidental adjustment of the needle valve.

Inasmuch `as the

bores

34 and 36 are, in one` embodiment, of identical size and shape, it `is possible to reverse the ball valve56 and needle valve 7) without altering the performance or operation of the power cylinder. `Reversal of these parts may be occasioned because of installation peculiarities wherein it may be desirable tohave the needle valve 7tlon one side instead of on the other.

As shown in FIG. 1, the` diameter of the aperture 22 is `uniform throughout the length thereof, this length being substantially equal to the thickness of the block 14. Thus, the entire thickness of this block `is available and is used to provide the necessary bearing support. This constitutes an advantage over prior art arrangements wherein communication with the cylinder chamber has been `providedby means of enlarged bores coaxial with the piston rod, becausethis prior `art arrangement requires the addition of bearing length whereby thetotal cylinder construction becomes longer. This invention provides both adequate bearing support as well as full and complete speed control in a construction smaller than the prior art permitted.

. Preferably, as shown in FIG. 9, the bearing aperture 22 is provided by a bearing assembly composed of two elongated,

cylindrical bushings

17 and 19 arranged endto-end as shown and` spaced apart axially to receive a hermetic sealing ring 21 of conventional design. The bushings 17 -and 19 may be fabricated of any suitable conventional bearing material such as sintered nylon. The sealing ring 21,which surrounds the rod 16 in hermetic sealing engagement therewith, conventionally seals the bearing assemblyand prevents leakage between the cylinder interior and the outside via the bearing assembly. This` sealing ring 21 may be of any suitable conventional material such as rubber. The ring 21 is engageably interposed between the two

bushings

17 and 19 and is situated about midway between the opposite surfaces 23 and `25, respectively, of the block 14. An annular Teflon Wiper 27, whichu surrounds the rod16, abuts against the right-hand end 1-TIG.` 9) of the bushing `19vand in turn is held in place by the inturned annular flange 29 which is nte- As the needle valve isbackedl farther outwardly, the piston will operate faster untif` the port orV gral with the block ld. Thus, the bearing

assembly

17, 19, 2l is retained against accidental dislodgement in av rightward direction from the block ld. Further than this, the bushings 1'7 and 19 are press fitted and hermetically sealed into an enlarged opening 3l in the bloclc 14. The piston rod ld can thereby conventionally reciprocate in the bearing aperture 22 as previously explained.. As FIG. 9 shows, the two

bushings

17 and 19 aggregatively are of a length substantially equal to the distance,I between the two

surfaces

23 and 25.

The blind port 80 (FIG. 9), which is relatively shallow as previously described, terminates short of the enlarged opening 3l and bearing aperture 22 thereby preventinr any direct communication between this blind port;

80 and the aperture 22. The sole communication be tween'this port 3@ and the interior of the cylinder it? is provided by the passages 69, 7S in the block la.

Referring to FlGS. 6, 7 and 8, typical air systems incorporating this invention and a comparable prior art:

arrangement are shown. In FlG. 6, the dashed line por tion is the prior art alternative to the full line piping hook-up leading from the power cylinder lll to the reversing valve 99. FIG. 7 diagrammatically illustrates the equivalent of this prior art alternative wherein the speed Control valve assemblies are not incorporated into the end blocks but instead are connected in series with the external lines. ln this prior art arrangement, the power cylinder end blocks are bored out in a conventional man-l ner to provide full communication between the

cylinder chambers

18, 2@ and the lines 36 and 8S. Speed control

n valve assemblies

94 and 96 are connected in series with the lines which are indicated by the numerals 86a and 63a, respectively. It will immediately be obvious that the volume enclosed by the piping between these

valves

94 and 96 must be added to the volumes of the cylinder chambers 1S and 2@ to determine accurately the total volume of air against which the piston must work. The larger the volume, the more air there is to be compressed, such that a piston of given size will necessarily have to move a correspondingly large distance before it Will encounter sufcient back pressure to control the movement thereof. Conversely, the smaller the volume, the same stroke of the piston will produce greater back pressure sooner thereby developing more resistance to movement. assemblies as closely as possible to the cylinder chambers i8 and 20, and the present invention provides the optimum for accomplishing this.

l If it is assumed that piston 13 is moved from its position of FIG. 1 toward the right, a given full pressure will immediately be applied to the left-hand side of the piston 13 and will remain so applied uniformly through the entire stroke. This pressure is uniform from start to finish. At the exhaust end, the air in chamber 20 immediately encounters the needle valve. The exhaust rate past this needle valve directly and instantly governs piston velocity such that this velocity is substantially Vuniform regardless of whether the piston stroke'is short or long. Location of the valve assemblies directly adjacent to the cylinder chambers ILS, Ztl provides for this precise and uniform control: to-wit, uniform application of power to the piston coupled with efcacious control of speed. While there has been described above the principles o this invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention.

y What is claimed is:

1. A fluid power cylinder comprising a hollow cylinder having opposite ends, a piston reciprocally received by said cylinder, two head blocks mounted on and closing the opposite ends respectively of said cylinder, a piston rod disposed coaxially of said hollow cylinder secured at one end to said piston and reciprocally projecting through one of said head blocks, said head blocks Thus, it is desirable to locate the control valve each having two parallel surfaces which are spaced apart in a direction axially ot said cylinder thereby providing thickness dimensions for said blocks, said blocks having orthogonally intersecting sides, piston rod-bearing means which includes an axially extending bearing aperture through said one block, said bearing aperture coaxially slidably receiving said piston rod, said bearing aperture extending between the surfaces of said one block and being of uniform diameter throughout the length thereof, the diameter of said aperture being substantially coextensive with the diameter of said rod, each said bloeit having rst and second identically shaped bores extending inwardly from two opposite sides respectively, a third bore in each block having inner and outer opposite rends, the outer end of said third bore opening through a third side of the block and the inner end being closed within said block thereby providing a blind port, said :blind port at its inner end communicating with the innermost ends of said first and second bores, each said rst and second bores being divided into two different diameter lengths with the innermost length being the rsmaller, each said lirst and second bores having a valve :seat provided at the joinder of the two different diameter lengths, the outermost ends of the larger diameter lengths Ebeing threaded, one of said irst and second bores receiving a ball valve engageable with the respective valve seat, :a closure nut threaded into the outer end of said iirst bore, a spring interposed between said ball valve and :said nut for urging said ball valve into sealing engagement with its valve seat, a retaining nut threaded into the outer end of the other of said tirst and second bores, ;a needle valve threadedly received by an opening in said retaining nut, said needle valve having a valve tip on `'its inner end which cooperatively engages the respective `valve seat, an integral annular collar on said needle valve :and movably disposed in the respective larger bore portion., said collar being of a diameter substantially coextens'ive with that ot said larger bore portion, said collar having a diameter larger than the opening in said retain- 1 ing nut and abuttable with said retaining nut as a stop,

a rubber O-ring frictionally litted onto said needle valve lintermediate said collar and said valve tip, said O-ring rictionally engaging said larger bore portion thereby restraining said needle valve against rotation and sealing :said larger bore portion, said blind ports extending in a Idirection normal to the axis of said cylinder, the blind port in said one block extending inwardly toward said bearing aperture but terminating short thereof, and two passages in each head block extending in directions parallel to said cylinder axis, one passage being connected between said first bore and the interior of said cylinder, the other passage being connected between said second bore and the interior of said cylinder, said valve seats of each block being disposed between said blind port and the respective passages.

2. A liuid power cylinder comprising a hollow cylinder having opposite ends, a piston reciprocally received by said cylinder, two head blocks mounted on and closing the opposite ends respectively of said cylinder, a piston rod disposed coaxially of said hollow cylinder secured at one end to said piston and reciprocally projecting through one of said head blocks, said head blocks each having two surfaces which are spaced apart in a direction axially of said cylinder thereby providing thickness dimensions for said blocks, said blocks having sides, piston rod-bearing means which includes an axially extending bearing aperture through said one block, said bearing aperture eoaxially receiving said piston rod, said bearing aperture extending between the surfaces of said one block and having an axially extending piston rodengaging area of cylindrical shapey which is of uniform cross-sectional size and shape throughout the axial extent thereof; each said block having first and second identically shaped bores extending inwardly from two opposite sides respectively, a third bore in each block havingV escaneo *inner and outer opposite ends, the outer end of said third bore opening through a side of the block and the inner end being closed within said block thereby providing a `blind` port, said blind port at its inner end communicating with the innermost ends of said iirst and second bores,

each said first and second bores being divided into two different diameter lengths with the innermost length being `the smaller, each said first and second boreshaving va valve and said nut for urging said ball valve into sealing `engager-nent withits valve seat, a retainingnut threaded into the outer end of the other of said rst and second boresr ,a-ne'edlevalve threadedly received by an opening `in saidpretaining nut, said needle valve having a valve tipon its inner end which cooperatively engages the respective valve seat, an integral annular collar on said needle valve'and movably disposed in the respective larger bore portion, said collar being of a diameter substantially coexte'nsive with` that 'of said larger bore portion, said collarfhaving a diameter larger than the opening in said retaining nut and abuttable with said retaining 'nut as a stop, a rubber O-ring 'frictionally iittedlonto said needle `valve intermediate said collar and said valve tip, said O-ring frictionally engaging said larger bore portion thereby restraining sa'id needle valve againstrotation and sealing said larger bore portion, said blind ports extend- `ingfina direction normal to the axis of said cylinder, the Vblind port in said one block extending inwardly toward'said bearing aperture 'but terminating short thereof, the rst and second bores in said one block also terminatingshort 'of said bearing aperture so as not to have "any dire-ct communication therewith, and two passages in each headjblock, one 'passage being connected between said iirst "bore and the interior of said cylinder, theothe'r passage being `connected betweensaid second bore and 'fthe` interior of said cylinder, .said valve seats Aoi each .block being disposed between `said blind port and the respective passages. 3. A uid power cylinder comprising a hollow cylinjder having oppositewehds a piston reciprocally received by said cylinder, two head blocks mounted on and clos- "ingthe opposite ends respectively of said cylinder, a piston rod disposed coaxially of said hollow cylinder Asecured at one end to said piston and reciprocally projecting through one of said head blocks, said head blocks each shape which is of uniform cross-sectional'size andshape throughout the axial `extent thereof; each said block having rst and second identically shaped bores extending 'inwardly from two opposite `sides respectively, a third bore in" each block and having'iniier and outer opposite ends, the oiiterend of said "third bore opening through a f third side of the block and the inner end being closed 'within `said block,'therebyrproyiding `a blind port, said blind port at its inner end communicating with the inner- :host ends of said iirst andsecond bores, each said `rst J[and second hores being divided into two different diam- Aeter lengths'with the innermost length beinglthe smaller, 'each saidiirst and second bores 'having a "valve seat pro- 'v'ided atthejoinderof the twodifferent diameter lengths, :the outermost ends `of uthe larger diameter lengths being threaded, one of said rst andsecond bores receiving a l@ ball valve engageable with the respective valve seat, a closure nut threaded into the outer end of said iirst bore, a spring interposed between said ball valve and said nut for urging said ball valve into sealing engagement with its valve seata retaining nut threaded `into the outer end of the other of said rst and second bores, a needle valve threadedly received by an opening in said retaining nut, said needle valve having a valve tip on its inner end which cooperatively engages the respective valve seat,sa`id blind ports extending in a direction normal to 'the axis of said cylinder, the blind port in said one block extending inwardly toward said bearing aperture but terminating short thereof, and two passages in each head block-extending in directionsparallel to said cylinder axis, one passage beingconnected between said first bore and the interior of said cylinder, the other passage being connected between said second bore and the interior of said i cylinder, said valve seatsof each block being disposed between said blind port @andthe respectivepassages.

4. For use 'in a fluid power cylinder, a hollow cylinder having opposite ends, a piston reciprocally received by said cylinder, two head blocks mounted on and closing the opposite ends respectively of said cylinder7 a piston rod secured at one end to said piston and reciproca-lly projecting through one of said head blocks, said head blocks each having a thickness which extends in a direction axially of said cylinder, one of said blocks having piston rod-bearing means which includes an axially extending bearingapeture through theentire thickness of said one block, said `bearing aperture coaxially slidably receiving lsaid piston rod, said 'bearing aperture having an axially extending piston rod-'engaging area which is of uniform cross-sectional size and shape throughout the axial extent thereof, said rod-'engaging larea extending substantially lcoextensively with the thicknessiof said one block; each said Vblock having first' and second bores extending inwardly from two opposite sides respectively, a third bore in each block and having innerand outer opposite ends, the outer end of'said third bore opening through a third side of the block and the inner endbeing closed within said block thereby providing a blind port, said blind port at Aits inner end communicating with the smaller, each `said rst and second bores having a valve Vseatprovidedlat the joinder ofthe two different diameter lengths, said blind ports 'extending in a direction normal to the axis of said cylinder, the blind `port in saidcne block extending inwardly toward said bearing aperture but terminating short thereof, and'two passages in each `headblock extending in directions parallel'to saidcylin'der axis, one passage being connected between said `iirs`t `ho`re `and the interior of said cylinder, the other passage being connected between said second bore `and the interior of said cylinder, said valve seats of each block beingdisposed betweensaid blind port and the respective passages.

5. A iluid power cylinder comprising a hollow cylinder having oppositeends, a piston reciprocally received'by said cylinder, two head blocks mounted `on and closing `the opposite ends respectively of s aid cylinder, a piston rod secured at one end to said p'iston and reciprocally projecting through'one of said head `blocks, said head blocks each 'having a thickness which extends in a direction axiallyv'of said cylinderhsaid one `block having piston rod-bearing means which includes an axiallyextending bearingaper- Ature through the entire thickness of said one block, said 'bearing aperture coaxially Ysealingly receiving said piston rod, said bearing aperture having an axially extending piston rod-engaging area which is slidably engageable with said piston rod throughout the axial extent oflsaid rod-engaging area, said rod-engaging area extending substantially coextensively with the thickness of said one block, each saidhlock having'first and second bores, a

i third bore in each'block andhaving inner andouter opposite ends, the outer end of said third bore opening through a side portion of the block and the inner end being closed within said block thereby providing a blind port, said blind port at its inner end communicating with the vinnermost ends `of said first and second bores, each said first and second bores having a valve seat, irst valve means provided in one of said rst and second bores in operative association with the valve seat thereof for shutting oif iiow in a direction from said one bore toward the respective blind port and for opening iiow in the opposite direction, second valve means provided in the other of said iirst and second bores in operative association with the valve seat thereof for controlling llow between said other bore and the respective blind port, said blind ports extending in a direction normal to the axis of said cylinder,

the blind port in said one block extending inwardly toward said bearing aperture but terminating short thereof, and two passages in each head block extending in directions parallel to said cylinder axis, one'passage being connected between said first bore and the interior of said cylinder, the other passage being connected between said second bore and the interior of said cylinder, said valve seats of each block being disposed between said blind port and the respective passages.

6. A fluid power cylinder comprising a hollow cylinder having opposite ends, a piston reciprocally received by said cylinder, two head blocks mounted on and closing the opposite ends respectively of said cylinder, a piston rod secured at one end to said piston and reciprocally projecting through one of said head blocks, said head blocks each having a thickness which extends in a direction axially of said cylinder, said blocks having a plurality of side portions, piston rod-bearing means which includes an axially extending bearing aperture through the entire thickness of said one block, said bearing aperture coaxially sealingly receiving said piston rod, said bearing aperture having an axially extending piston rod-engaging area which is slidably engageable with said piston rod throughout the axial extent of said rod-engaging area, said rodengaging area extending substantially coextensivelyfwith the thickness of said one block, each said block having first and second bores, a third bore in each block and having inner and outer opposite ends, the outer end of said third bore opening through a side portion of the block and the inner end being closed within said block thereby providing a blind port, said blind portA at its inner end communicating with the innermost ends of said first and second bores, each said iirst and second bores having a valve seat,iirst valve means provided in one of said Iirst and second bores in operative association with the valve seat thereof for shutting oif flow in a direction from said vone bore toward the respective blind port and for opening flow in the opposite direction, second valve means provided in the other of said first and second bores in operative association with the valve seat thereof for controlling ow between said other bore and the respective blind port, the blind port in said one block having no direct communication with said bearing aperture, and two passages in each headblock, one passage being connected between said first bore and the interior of said cylinder, the other passage being connected between said second bore and the interior of said cylinder.

7. A fluid power cylinder comprising a hollow cylinder having opposite ends, a piston reciprocally received by said cylinder, two head blocks mounted on and closing the opposite ends respectively of said cylinder` a piston rod secured at one end to said piston and reciprocally projecting through one of said head blocks, said head blocks each having a thickness which extends in a direction axially of said cylinder, said blocks having a plurality of side portions, piston rod-bearing means which includes an axially extending bearing aperture through the entire thickness of said one block, said bearing aperture coaxially sealingly receiving said piston rod, said bearing aperture having an axially extending piston rod-engaging ai en.;

area which is slidably engageable with said piston rod throughout the axial extent of said rod-engaging area, said rod-engaging area extending substantially coextensively with the thickness of said one block, each said block having first and second bores, a third bore in each block and having inner and outer opposite ends, the outer end of said third bore opening through a side portion of the blocl and the inner end being closed within said block thereby providing a blind port, said blind port at its inner end communicating with the innermost ends of said rst and second bores, means providing communication between lsaid rst and second bores of each block and the interior of said cylinder, means in the irst bore of each block for limiting ow of fluid in only the direction from the blind port to the cylinder interior, and means in the second bore of each block for restricting the flow of fluid from said cylinder interior to the blind port thereof.

S. A. iiuid power cylinder comprising a hollow cylinder having opposite ends, a piston reciprocally received by said cylinder, two head blocks mounted on and closing the opposite ends respectively of said cylinder, a piston rod disposed coaxially of said hollow cylinder secured at one end to said piston and reciprocally projecting through one of said head blocks, said head blocks each having two surfaces which are spaced apart in a direction axially of said cylinder thereby providing thickness dimensions for said blocks, said blocks having sides, piston rod-bearing means which includes an axially extending bearing aperture through said one block, said bearing aperture coaxially receiving said piston rod, said bearing aperture extending between the surfaces of said one block and having an axially extending piston rod-engaging area of cylindrical shape which is of uniform cross-sectional size and shape throughout the axial extent thereof; each said block having first and second bores extending inwardly from two opposite sides respectively, a third bore in each block having inner and outer opposite ends, the outer end of said third bore opening through a side of the block and the inner end being closed within said block thereby providing a blind port, said blind port at its inner end communivcating with the innermost ends of said first and second bores, each said first and second bores being divided into two different diameter lengths with the innermost length being the smaller, each said iirst and second bores having a valve seat provided at the joinder of the two different diameter lengths, the outermost ends of the larger diameter lengths being threaded, one of said first and second bores receiving a ball valve engageable with the respective valve seat, a closure nut threaded into the outer end of said rst bore, a spring interposed between said ball valve and said nut for urging said ball valve into sealing engagement with its valve seat, a retaining nut threaded into the outer end of the other of said first and second bores, a needle valve threadedly recieved by an opening in said retaining nut, said needle valve having a valve tip on its inner end which cooperatively engages the respective valve seat, said blind ports in said blocks extending in a direction normal to the axis of said cylinder, the blind port in said one block extending inwardly toward said bearing aperture but terminating short thereof, and two passages in each head block, one passage being connected between said iirst bore and the interior of said cylinder, the other passage being connected between said second bore and the interior of said cylinder, said valve seats of each block being disposed between said blind port and the respective passages.

9. A fluid power cylinder comprising a hollow cylinder having yopposite ends, a piston reciprocally received by said cylinder, two head blocks mounted on and closing the opposite ends respectively of said cylinder, a piston rod disposed coaxially of said hollow cylinder secured at lone end to said piston and reciprocal-ly projecting through one of said head blocks, said yhead blocks each having two surfaces which are spaced apart in a direction axially of said cylinder thereby (providing thickness dimensions for i3 said blocks, said blocks having sides, piston rod-bearing means which includes an axially extending bearing aperture through said one block, said bearing aperture coaxially receiving said piston rod, each said block having first and second bores extending inwardly from two 0pposite sides respectively, a third bore in each block having inner and outer opposite ends, the outer'end of said third bore opening through a side of the block and `the inner end being closed within said block thereby providing a blind port, said blind port at its inner end communicating with the innermost ends of said first and second bores, each said iirst and second bores being divided into two different diameter lengths With the innermost length being the smaller, each said first and second bores having a valve seat provided at the joinder of the two diferent diameter lengths, the outermost ends of the larger diameter lengths being threaded, one of said rst and second bores receiving a ball valve engageable with the respective valve seat, a closure nut threaded into the outer end of said iirst bore, a spring interposed between said ball valve and said nut for urging said ba-ll valve into sealng engagement with its valve seat, a retaining nut threaded into the outer end of the other of said iirst and second bores, a needle valve said needle valve having a valve tip on its inner end which cooperatively engages the respective valve seat, said blind ports in said blocks extending in a direction normal to the axis of said cylinder, the blind port in said one block extending inwardly toward said bearing aperture but terminating short thereof, and two passages in each head block, one passage being connected between said first bore and the interior of said cylinder, the other passage being connected between said second bore and the interior of said cylinder, said valve seats of each block being disposed between said blind port and the respective passages.

References Cited bythe Examiner'V UNITED STATES PATENTS SAMUEL LEVINE, Primary Examiner.

FRED E. ENGELTHALER, Examiner.

Claims

1. A FLUID POWER CYLINDER COMPRISING A HOLLOW CYLINDER HAVING OPPOSITE ENDS, A PISTON RECIPROCALLY RECEIVED BY SAID CYLINDER, TWO HEAD BLOCKS MOUNTED ON AND CLOSING THE OPPOSITE ENDS RESPECTIVELY OF SAID CYLINDER, A PISTION ROD DISPOSED COAXIALLY OF SAID HOLLOW CYLINDER SECURED AT ONE END TO SAID PISTON AND RECIPROCALLY PROJECTING THROUGH ONE OF SAID HEAD BLOCKS, SAID HEAD BLOCKS EACH HAVING TWO PARALLEL SURFACES WHICH ARE SPACED APART IN A DIRECTION AXIALLY OF SAID CYLINDER THEREBY PROVIDING THICKNESS DIMENSIONS FOR SAID BLOCKS, SAID BLOCKS HAVING ORTHOGONALLY INTERSECTING SIDES, PISTON ROD-BEARING MEANS WHICH INCLUDES AN AXIALLY EXTENDING BEARING APERTURE THROUGH SAID ONE BLOCK, SAID BEARING APERTURE COAXIALLY SLIDABLY RECEIVING SAID PISTON ROD, SAID BEARING APERTURE EXTENDING BETWEEN THE SURFACES OF SAID ONE BLOCK AND BEING OF UNIFORM DIAMETER THROUGHOUT THE LENGTH THEREOF, THE DIAMETER OF SAID APERTURE BEING SUBSTANTIALLY COEXTENSIVE WITH THE DIAMETER OF SAID ROD, EACH SAID BLOCK HAVING FIRST AND SECOND IDENTICALLY SHAPED BORES EXTENDING INWARDLY FROM TWO OPPOSITE SIDES RESPECTIVELY, A THIRD BORE IN EACH BLOCK HAVING INNER AND OUTER OPPOSITE ENDS, THE OUTER END OF SAID THIRD BORE OPENING THROUGH A THIRD SIDE OF THE BLOCK AND THE INNER END BEING CLOSED WITHIN SAID BLOCK THEREBY PROVIDING A BLIND PORT, SAID BLIND PORT AT ITS INNER END COMMUNICATING WITH THE INNERMOST ENDS OF SAID FIRST AND SECOND BORES, EACH SAID FIRST AND SECOND BORES BEING DIVIDED INTO TWO DIFFERENT DIAMETER LENGTHS WITH THE INNERMOST LENGTH BEING THE SMALLER, EACH SAID FIRST AND SECOND BORES HAVING A VALVE SEAT PROVIDED AT THE JOINDER OF THE TWO DIFFERFENT DIAMETER LENGTHS, THE OUTERMOST ENDS OF THE LARGER DIAMETER LENGTHS BEING THREADED, ONE OF SAID FIRST AND SECOND BORES RECEIVING A BALL VALVE ENGAGEABLE WITH THE RESPECTIVE VALVE SEAT, A CLOSURE NUT THREADED INTO THE OUTER END OF SAID FIRST BORE, A SPRING INTERPOSED BETWEEN SAID BALL VALVE AND SAID NUT FOR URGING SAID BALL VALVE INTO SEALING ENGAGEMENT WITH ITS VALVE SEAT, A RETAINING NUT THREADED INTO THE OUTER END OF THE OTHER OF SAID FIRST AND SECOND BORES,