US2949080A

US2949080A - Pressure generator

Info

Publication number: US2949080A
Application number: US709992A
Authority: US
Inventors: Jack B Ottestad; Jr Samuel A Skeen
Original assignee: General Dynamics Corp
Current assignee: General Dynamics Corp
Priority date: 1958-01-20
Filing date: 1958-01-20
Publication date: 1960-08-16
Anticipated expiration: 1977-08-16

Description

Aug. 16, 1960 J. B. oTTEsTAD ETAL 2,949,080

PRESSURE GENERATOR Filed Jan. 20, 1958 2 Sheets-Sheet 1 Afm/s1.. Apr-Hue SMEs, ,Iz

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Aug. 16, 1960 J. B. oTTEsTAD ET AL 2,949,080

PRESSURE GENERATOR Filed Jan. 20, 1958 2 Sheets-Sheet 2 l 132/ A l i g sg z 9c .we 5 a 150;: '9i l clac-M He-ww rrssmo, f i M2 sa 104 Samuel. Ain/ae Seis/zj? :40` Y .IZ/veums.

' ffice v Patnteclrnig; .16, 19.60

GENERATOR Jack ttestad,.-Claremont, and-Samuel A. Skeen, Jr., West Covina, Calif., assignorsto General Dynamics Corporation, San Diego, Calif., a corporation of Delaware r n Filed Jan. 20, 1953, Ser. No. 709,992

16 Claims; (Cl. 10S-50) This invention relates generally to pressure generators; more particularly, it relates vto pressure generators for effecting rapid pressure variation.

The pressure generator ofthe present invention utilizes actuator means for rapidly exerting thrust on plunger means positionedv in a cylinder to produce pressure. The actuator means` is adapted for very rapid production of thrust, and utilizes features of actuators described and claimed in the copending application of I ack B. Ottestad, Serial No. 617,0?14, tiled October 19, 1957, the copending application of .lack B. Ottestad and Samuel A. Skeen, SerialY No. 683,855, tiled September 13, 1957, and the copending application of Jack B. Ottestad, Serial No. 690,774 tiled October I7, 1957. A preferred embodiment of the present invention utilizes actuator adjustment means for governing rthe time variation of thrust on the plunger means to predetermiue an initial pressuretime pattern.

lt is accordingly an object of the present invention to provide a pressure generator' capableof very rapid production of high pressure.

An object of this invention is the provision of a pressure generator capable ofA producinga predetermined pressure-time pattern.

It is .an object of this invention tofprovide a pressure pump which is adjustable for selection of an initial pressure-time output pattern.

An object of the present invention is the provision of a pressure generator which is adjustable for predetermination ofthe time duration of pressure increase.

Other objects' and features of the' present invention, as well as many advantages thereof, will become apparent to those skilled in the art from a consideration ofV the following description, the appended rolaims, :andthe accompanying drawings, in which:

Figure 1 is a perspective view, partially in section, of a preferred embodiment of the pressurexgenerator of this invention;

Figure 2 is an elevational view, partially, in' sectionof the pressure generator shown in Figure l;I

Figure 3 is a sectional perspective view showing 4details of a portion ofxthe embodimentshown inl Figures l and 2;

`Figure 4 is a fragmentary elevationaly view of'amodied form of pressure generator according to the present invention; and

Figures 5 and 6 are graphical representationsof pressure-time patterns produced by a pressure generator. of this invention under certain conditions of .operation and adjustment.

Referring to the drawings, and particularly to Figures 1, 2, and 3, a preferred embodiment of the present invention is shownasincluding-base member'l, ank end member 12, a pump end wall 14, an actuator end Wall i6, a cylindricalnpump housing 18and a: cylindrical actuator housing or outer cylinder 20. Thesef'parts are secured in clamped relation byti`e.bolts- 2X2-.to form a housing. The tie-bolts extend through appropriate open- Z ings equally spaced: about a flange portion 24 ot-.theebas member and throughsimilar aligned openings ina ilange' portion 26 of the end member.

28. Cylindrical' pump housing 18' abuts lthe ilange por# tion 26 and iit's closely' about' a cylindrical section 30v of the end member'. Pressure sealing between section 30 and the pump housing is provided by an annular sealr 32 disposed' in an appropriate groove jin the section. The end of the pump housing opposite the end' member is titted about areduced portion' 34 of thevpuxnpL end-wall', and sealingV is provided'betweenthese parts byarrannular sealing element 36. Y f l,

Ar body portion 4.0 of the base Ymen'tber-tits closely within the outertactuator cylinder 20,'tl'1'eendofwhich; abuts ange portion 24 ofthe 4base member. Pressure. sealing lbetween' 4the actuator housing and'thelbfase" mem-J beris provided by yan appropriate seal 42 disposed in a: peripheral groove in the body portion adjacent to the' ilange portion. The other end of the cylindrical actu= ator housing is accommodated by actuatork endy wall 16" in the same manner as pump housing`18 i's accommoi dated by pump end wall"v 14, and pressure sealing is' similarly provided.

A pump casef44-is coaxial w-iththepurnp` housing and has the end of its cylindrical portion or pump" cylinder 45 seated in a circular recess 48 .in-the pump end Wall. Openings '50 are provided' in cylindrical portionf46`-n`ear` the end thereof. Avheadportion 52. of the pump oase is adapted to tit within an. opening 5'4 in' end' member 1'2' and is maintained in: clamped relationwith theVV end-mem; .berY by means of mutually engaging' shoulders" ati 56; A resilient sealing' ring 58 in aperipheral groove in? the pump case provides pressure seal-ing. axial opening 60 in head portion 52 is threaded'to accommodatean ou't let coupling 62.

From the `foregoing/ description, it Vwillbe understood that cylindrical portion 46 of pump case- 44 vand pump end wall 14 dene apumptchamb'er 64'. VVT'lie'pump endl wall, end member T2, the pump/ case'V andL cylindrical pump housing 1'8' cooperate to dene' asupply'chamber 66, which is coaxial-withthe'pumpehamber. IA 'palvssageV 6s in the end member andLaautd-ooupungvu interconnect the supply chamber ywith'A a sourcel of (not shown). j

Al pump piston orplun'ger72 is slida'bly positioned within the pump cylinder-` 46 oir" the'V pumpAv case; threaded axial opening 74 in the' pump pistonsecurefs a threaded end por-tion of a thrust column 76i The'thr'ust column extends' throughanopening'` 78"/in` thepumpI end' wall and through an aligned opening 80 in the actuator end wall, these openingshbeing maintained inl alignment .by a concentricity ring.Y 82,-which is seated in' adjoining recesses in the two endwalls-so as to Itit closely'aro the' thrust eolur'nn. A groove 84vr within each ofthe

openings

78 and 80 accommodates a sealing' member which provides pressure Vsealing betweenthe' thrust col umn and the end walls. Opening Sil-has4 an enlarged threaded portiony within which is' securedL athrust bearing 86.

An inner" actuator .cylinder 901 is disposed in I relation with cylindrical actuator housing 205. The i ner cynnder abuis actuators-admitirlo and-ntsiosely' about' a reducedy wa'll section 912', which accommodates apres#y sure sealing ring.' Anactuator -piston`194 is slidablfy` positioned within the'. -i'nner lactuator cylinder' andfi's secured tov the thrust column byL engagementiwfijits threaded axial .openingj96 rwith' a threaded .e'ndI portiox of the thrust` column'. vPressure sealing vbetween*the actuator piston audinnercylinder is providedby an annular seal 98 I disposed in ,a peripheral `-grooye .i'n fthe@ piston.

The tie-.bolts are securedv by engagement of their threaded end portions with nuts In the modified form of the present invention shown in Figure 4, nd pump piston is utilized. An end portion 160 of thrust column 76 serves as a plunger and a cylindrical section 162 of the pump case is adapted to fit the thrust column. In all other respects the modified form is similar to the embodiment shown in Figures 1, 2

and 3. 1. The pump piston and the thrust column, together with eitherl pump piston 72 or plunger portion 160, may be considered to constitute pisto'n means slidably positioned in cylinder means comprised of inner actuator cylinder 90 and cylindrical portion 46 of the pump case.

Theend of inner actuator cylinder 90 opposite from the" actuator end wall secures an orice plate or wall -100 in wedge-shaped recesses 1027of base, member 10 by engaging a ange po'rtion 104 of the orifice plate. A pressure sealing ring 106 is disposed between the cylinder andthe orifice plate in an appropriate groove inthe plate adjacent to the ange portion. An orifice 108 is defined in the-orifice plate and a circular resilient seal 110 is secured as by bonding in a circular groove in the orifice plate, these elements serving purposes which are explained hereinbelow. As shown in Figure 3, the abovementio'ned wedge-shaped recesses 102 are defined by four mutually perpendicular radial grooves 112, which define four wedge-shaped sections 114 of the body portion, and by a circular recess of less depth than the grooves 112, which is machined in the body portion 40 to produce a wedge-shaped recess on each o'f the four sections 114.

. It will be observed that the inner cylinder 90, actuator end wall 16 and the orifice plate cooperate to define a rst pressure chamber or actuator chamber 116 and that the :actuator housing, the actuator end wall and base member cooperate to define a seco'nd pressure chamber or accumulator chamber 118. The orifice plate and the base member cooperate to define passages between chamber 118 and orifice 108 through the radial grooves 112. -A passage 120 in the base member and a uid coupling 122 interconnect the second pressure chamber 118 and a source of pressure (not shown). A similar passage 124 in the actuator end wall and an external fluid connection 126 connect the first chamber 116 with another source of pressure (not shown).

A threaded opening 128 in inner cylinder 90 adjacent to the orifice plate secures an elbow coupling 130, which is joined through appropriate connectionswith a check valve 132. The valve communicates directly with the interior of pressure chamber 118. Means are thereby provided for releasing pressure above a certain value from chamber 116 to chamber 118, for a purpose which is explained hereinbelow.

A threaded axial opening 136 in the base member accommodates an adjustment assembly 138. A shoulder 140 is provided in the o'pening for seating the assembly. Adjustment assembly 37 includes a retainer 142, an enlarged threaded portion 144 of which secures the assembly in opening 136. Pressure sealing between the base member and a reduced portion 146 of the retainer is effected by a resilient seal ring 148 disposed in an annular groove within the opening. A threaded bore in the rerainer accommodates a threaded shank portion 152 of an adjustment element o'r needle 150. Pressure sealing is provided between the retainer and the adjustment needle. The needle is coaxial with orifice 108 and has a conical plug or head 154 which is extended or retracted upon rotation of the needle in the container. A screw slot 1 56 is provided in the end of shank portion 110 to provlde external adjustment means fo'r selectively positioning conical plug 1-54 relative to the orifice plate 100.

A I n operation, the pressure generator hereinbefore described is capable of producing high pressure very rapidly. To prepare the apparatus for operation, chambers 66 and 64 are lled with uid which is introduced throughpassage 68. In filling chamber 64, the fluid 4 passes between the pump piston and the pump case, there being no static pressure seal between these members and appropriate clearance being provided between the piston and the case. The chambers 64 and 66 are part of a pressure system which is closed after the chambers are filled.

The actuator portion of the pressure generator exerts thrust on the actuator and pump pistons very rapidly. The method of effecting this sudden action through the coaction of the orifice plate 100, circular resilient seal and the actuator piston 94 is described in the copending applications mentioned hereinabove. It is briefly ydiscussed herein for convenience in relating it to the pressure generator of the present invention.

A setting pressure is introduced into the actuator chamber through fluid coupling 126 and passage 16 from a source of pressure (not shown). The actuator piston is thereby seated against circular resilient seal 110 to effect apositive pressure seal which isolates chamber 116 from chamber 118. A high actuating pressure is introduced into chamber 118 through fluid coupling 122 and passage in base member 10. The actuating pressure acts upon the area of the piston within seal 110 and is predetermined to balance the force of the setting pressure acting upon the larger area on the opposite side of the piston. Piston 94 is thus held in equilibrium. The pressure in chamber 118 is next increased by a pressure differential sufficient to unbalance the forces on the piston and cause movement of the pisto'n from the orifice plate. Seal 110 is thereby disengaged and the high actuating pressure is thus released substantially instantaneously to act upon the area of the piston outside circular seal 110. A great net force is thus suddenly exerted on the actuator piston and is transmitted to the pump piston 72. Circular seal 110 is au important element in making possible this extremely rapid production o'f high force; it is adapted for sudden disengagement from the orifice plate for the purpose of releasing the actuating pressure substantially instantaneously.

lIn order to prepare the actuator for repeat operation,

actuator piston 94 must be re-seated against the orifice plate to re-establish pressure sealing between the piston and the plate by means of resilient circular seal 110. On re-seating the piston by reducing the pressure in chamber 118 to a value slightly below that in chamber 116, a pressure approximating the reduced pressure is trapped by circular seal 110 and by seal 98 between the piston and the orifice plate. If this trapped pressure were not relieved, it would tend to oppose the force exerted by the setting pressure on the opposite side of the piston. The opening 128 in the inner actuator cylinder, the elbow coupling and unidirectional check valve 132 provide means for automatically relieving the trapped pressure into chamber 118. The valve is opened by a predetermined trapped pressure. The pressure is relieved into chamber 118, because if it were released to the exterior atmosphere the actuating pressure which passes through the orifice to actuate the piston would obviously be released to the atmosphere. The very rapidly produced high thrust is translated by the pump piston 72 into a high pressure generated in chamber 64 at an extremely high rate. It will therefore be appreciated that the present invention is capable of very rapid or substantially instantaneous production of very high pressure.

Although the fluid in pump chamber 64 may be a gas it is considered preferable to utilize a liquid. The relative incompressibility of liquid results in more rapid attainment of higher. pressures. In further discussion herein, it is assumed that liquid is used in the pump chamber.

The output pressure-time pattern at output opening 60 is in accordance with the thrust-time pattern produced on the actuator piston 94.

In Figure v is shown a pressure-time pattern produced in the manner described above. A very rapid pressure rise or surge at 164 is followed by the attaining of maximum pressure at 166, the elbow of the curve representing the full compression of the fluid against the piston. The maximum output pressure which is produced, and the degree of pressure amplification which is obtained, depend upon the values of the actuating and setting pressures, and upon the ratio of the actuator piston area to the pump piston area. As an example of the pressures which may be obtained, if an actuator pressure of 2,000 pounds per square inch is utilized with an actuator piston area of 4 square inches and a pump area of 1 square inch, an output pressure of 32,000 pounds per square inch is obtainable. The amplification ratio is therefore governed by the ratio between the actuator piston area and the pump piston area. It has been found that maximumy pressure is attainable in approximately one-quarter of a millisecond.

An initial pressure other than zero may be selected by establishing such pressure in chamber 64 before activating the actuator. In Figure 6 is shown an initial output pattern 172 where an initial pressure is established.

After maximum pressure is attained, assuming that the external pressure system does not relieve the pressure, the pressure may be maintained for a Vperiod dependent upon the rate of leakage of the iluid in chamber 64'past the pump piston 72. If a pressure seal were provided between the pump piston and the pump case, the output pressure could be maintained by maintaining the actuating pressure against actuator piston 94; With such a seal, it would be necessary to fill chamber 64 through the outlet opening or in some other manner.

With the pressure generator connected with an external pressure system which provides'volnme displacement-to permit substantial movement of the pump piston, a principal factor governing the initial pressure-time pattern is the degree of restriction upon the release ofpressure between chamber 118 and the 'actuator piston. After disengagement of circular'seal 110 by the action of the actuating pressure on the actuating piston, the actuating pressure must be released to the piston through the passages between the base member and the orifice plate and-through the orifice. The degree of restriction upon this release is determined by the design of a particular actuator. Utilizing particular pressures in

chambers

118 and 116, the restriction inherent in the design of a particular actuator produces a specific pressure-time envelope.

An important feature of the present invention is the provision of means for adjusting the degree of restriction to release of pressure to the actuator piston. This feature permits selective throttling Within the available pressure-time envelope `and predetermination of theV pattern or duration of output pressure rise. Adjustment needle 150 serves to accomplish this selection and predetermination by adjustment lof the netV flow area between the orifice plate 100 and plug portion 154V of the adjustment needle, thereby governing the pressure drop across orilice 108 as Ia function of piston displacement. `Adjustment needle 150 is axially adjustable, by means of the screw slot 156 disposed outside the pressure generator, so that head or plug 154 may be selectively positioned relative to the orifice plate to determinev the net flow area. Reduction in flow area throttles the actuating pressure and results in increased. velocity through the orifice. Increased velocity results in increased pressure dropr acrossthe orifice and ingreater throttling or `limiting effect` on. the. available pressure-time envelope.

In Figure 5 are shown pressure-time curves showing pressure rise patterns for different positions of adjustment needle 150. Curve 1.64-166 represents thepressuretime pattern which is produced with the adjustment plug fully withdrawn from the orifice. This curve therefore represents the available envelope within which. desiredly to`

curves

164, 168 and 172 of Figure 5 and represent the condition where an initial pressure is established in the pumpy chamber.

From the foregoing description, it will bek understood that the adjustment means may be utilized for selection of the initial portion of the Ypressure-time output pattern of the pressure generator of the present invention. lt may'also be utilizedl for predetermination of the time duration or rate `of pressure rise to maximum pressure. It has been found that this time duration may be selectively varied. between 250 microseconds` and 6 milliseconds.

It will be appreciated that the present invention is capable of very rapid or substantially instantaneous production of very high pressures. It will be furthe-r appreciated that this invention provides a pressure generator which is externally adjustable to permit predetermination of the initial portion of a pressure-time output pattern and of the time or. rate of pressure increase.

The capabilities of thewpresent invention make possible the precise control of the-rate of application of pressure for external use. Such control is important in such applications as thetesting of pressure gauges, especially the testing of such gauges under surge conditions. A-n important application` is: the forming 'of metal parts. A high controlled rate of pressure application permits the forming of. metal at an optimum rate which prevents workhardening of the metal and therefore precludes splitting or destruction.

Although specific embodiments of the present invention have been described andillustrated in detail, it is to be clearly understood that the same are by way of illustration and. example only; it is to be' understood that the invention is not limited'thereto, as many Variations will be readily apparent to those versed in the art and the invention is to be given its broadest possible interpretation within the terms of the appended claims.

The inventors claim:

l. A pressure generator comprising cylinder means, means dening an outlet opening in the cylinder means, piston means slidably positioned. in the cylinder means, said piston means having a plunger surface and an` actuator surface rigidly interconnected to provide a unitary structure, saidplunger surface confronting fluid disposed in the cylinder means, a plate confronting said actuator surface and defining an'orilice, a resilient seal element disposed between the actuator surface and the plate for eecting pressure sealing therebetweenaabout said orifice, means for exerting a setting force on said piston means to urge the actuatorV surface t-oward said plate tol cover the orifice and effect said pressure sealing, and means for establishing `an actuating pressure independent of said setting force to act upon a'portion of saidl actuator surface within the resilient seal element to overbal'ance the setting force and expose an increased area of the actuator surface to the actuating pressure, whereby thrustis exerted on said piston means to produce output pressure-in said fluid.

2. A pressure generator comprising cylinder means, y

between the actuator surface and the plate for effecting t area therebetween, thereby providing predetermined restriction to release of said actuating pressure to said actuator surface upon said overbalancing of said setting force to disengage said sealing means, whereby a thrust pattern on said piston means is governed to predetermine a pressure-time output pattern.

3. A pressure generator comprising housing means defining adjacent actuator and pump chambers, a plate defining an orifice at an end of said actuator chamber, an actuator piston positioned within said actuator chamber and confronting the plate, plunger means rigidly connected in a unitary structure with said actuator piston and slidably positioned in said pump chamber, said plunger means being adjacent to fluid in said pump chamber, a resilient seal element positioned between the actuator piston and the plate for effecting pressure sealing therebetween -about the orifice, means for applying fiuid setting pressure to the piston to exert a setting force urging the piston toward the wall to cover the orifice and effect said pressure sealing, and means for establishing in said second chamber an actuating pressure independent of said setting force to act upon a portion of the actuator piston within said resilient seal element to overbalance said force and expose an increased area of the actuator piston to the actuating pressure, whereby thrust is exerted on said plunger means to produce output pressure in said pump chamber.

4. A pressure generator comprising means defining a pump chamber having an outlet opening, said pump chamber being connected with a fluid pressure system, plunger means positioned within the pump chamber, a thrust column rigidly attached to said plunger means and extending through a wall of the pump chamber, an actuator piston rigidly connected with the plunger means and slidably positioned in an actuator chamber, a plate confronting the actuator piston and defining an orifice at an end of the actuator chamber, a resilient seal disposed between said actuator piston and said plate for effecting pressure sealing therebetween about the orifice, fluid pressure means for exerting a setting force urging the actuating piston toward the plate to cover the orifice and effect said pressure sealing, and means for establishing an actuating pressure independent of said setting force to act upon a portion of the actuator piston within the resilient seal to overbalance said force and expose an increased area of the actuator piston to the actuating pressure, whereby thrust is exerted on said plunger means to produce output pressure in said fluid pressure system.

5. A pressure generator comprising means defining a pump Vchamber having an outlet opening, said pump chamber being connected with a fiuid pressure system, plunger means positioned within the pump chamber, a thrust column rigidly attached to said plunger means and extending through a wall of the pump chamber, an actuator piston rigidly connected with the plunger means and slidably positioned in an actuator chamber, a plate confronting the actuator piston and defining an orifice at an end of the actuator chamber, sealing meansJ disposed between said actuator piston and said plate for effecting pressure sealing therebetween about the orifice, means for exerting a setting force urging the actuating piston toward the plate to cover the orifice and effect said pressure sealing, means for establishing an actuating pressure independent of the setting force to act upon a po.- tion of the actuator piston within the sealing means to overbalance said force and expose an increased area of the actuator piston to the actuating pressure, and an adjustment element selectively positionable relative to said plate for predetermining a net flow area therebetween, thereby providing predetermined restriction to release of said actuating pressure to said actuator piston upon said overbalancing of said .setting force to disengage said vsealing means, whereby a thrust-time pattern on said plunger means is governed torpredetermine a pressuretime output pattern.

6. A pressure pump comprising a pump case having an outlet opening communicating with a pressure system, plunger means positioned within the pump case, actuator housing means including an outer cylinder having closed ends, an inner cylinder coaxial with said outer cylinder and cooperating therewith to define a pressure chamber, a plate defining an orifice at an end of the inner cylinder, means defining at least one passage communicating between said pressure chamber and said orifice, an actuator piston rigidly connected in a unitary structure with the pump piston and positioned within said inner cylinder in confronting relation with said plate, a resilient seal disposed between the actuator piston and the plate for effecting pressure sealing therebetween about said orifice, means for establishing a uid setting pressure in the inner cylinder to exert a setting force urging the actuator piston toward said plate to cover said orifice and effect said pressure sealing, and means for establishing an actuating pressure in said pressure chamber independent of said setting pressure to act upon a portion of the actuator piston withinthe resilient seal to overbalance said force and expose an increased area of the actuator piston to the actuating pressure, whereby thrust is exerted on said plunger means to produce output pressure in said pressure system.

7. A pressure generator comprising a pump case having an outlet opening communicating with a pressure system, a thrust column having a plunger portion slidably positioned in the pump case, actuator housing means including an outer cylinder having closed ends, an inner cylinder coaxial with said outer cylinder and cooperating therewith to define a pressure chamber, a plate defining an orice at an end of the inner cylinder, means defining at least one passage communicating between said pressure chamber and said orifice, an actuator piston attached to said thrust column and positioned within said inner cylinder in confronting relation with said plate, sealing means disposed between the actuator pistonand the plate for effecting pressure sealing therebetween about said orifice, means for establishing a setting pressure in the inner cylinder to exert a setting force urging the actuator piston toward said plate to cover said orifice and effect said pressure sealing, means for establishing an actuating pressure in said pressure chamber to act upon a portion of the actuator piston within the sealing means to overbalance said force and expose an increased area of the actuator piston to the actuating pressure, and an adjustment element selectively positionable relative to said plate for predetermining a net flow area therebetween, thereby providing predetermined restriction to release of said actuating pressure to said actuator piston upon said'overbalancing of said setting force to disengage said sealing means, whereby a thrust-time pattern on said plunger portion is governed to predetermine an initial pressure-time output pattern,

8. A pressure generator comprising means defining a pump chamber disposed on a first side of a wall, an outlet opening in the pump chamber communicating with a pressure system, a pump piston slidably positioned within the pump chamber, a thrust column rigidly attached to the pump piston and extending through an opening in said wall, an actuator cylinder extending from the wall and cooperating therewith to define a first pressure chamber on a second side of said wall, actuator housing means cooperating with the wall and the actuator cylinder to define a second pressure chamber, a plate defining an orifice'. between the first pressure 'chamber and the second pressure chamber, an actuatcrpiston rigidly attached to the thrust column, said pistonvbeing'positioned in the' first pressure chamber in confronting relation with said plate, a resilient seal positioned between the actuator piston and theplateA for effecting pressure sealing therebetween about said orifice, means forV establishing a fiuid setting pressure inthe first pressure chamber to exert -a setting force urging said actuator piston towardV the. plate to cover the orifice and effect saidpressure sealing, and means for establishing in the second chamber an actuating pressure independent of said setting force to -act upon a portion of said actuatorl piston within4 said resilient seal to overbalance said force and expose an. increased area of the actuator piston to the actuating pressure, whereby thrust is exerted on said pump piston to produce output pressure insaid pump chamber.

9. A pressure generator comprising means defining a pump chamber disposed on a first side ofa wall, an outlet openingl in the pump chamber communicating with a ypressure system, a pump piston jslidably positioned within the pump chamber, a thrust column attached to the pump piston andextending through an opening in said wall, an actuator cylinder extending Vfrom the wall and cooperating therewith to define la first pressure chamber on a second side of said wall, actuator housing means cooperating with the wall and ,'theactuator cylinder to define a second pressure chamber, a plate defining an orifice between thefirst pressure chamber and the second pressure chamber, an actuator piston attached to the thrust column, said lpiston being positioned in the rst pressure chamber in confronting relation with said plate, sealing means positioned between the actu-ator piston and the plate for effecting pressure sealing therebetween about said orifice, means for exerting. aA setting. force urging said actuator piston toward the plate to cover the orifice. and effect said pressure sealing, means for establishing in the second ,chamber an actuating-pressure to act upon a portion of said actuator piston withinsaid sealing means to overbalance said force and expose an increased. area of the actuator piston to the actuating pressure, and an adjustment needle for restricting the release of the actuating pressureagainst the actuator piston. upon` said overbalancing of' the setting force to disengage said sealing means, said adjustment needle havinga head portion for extension toward said orifice plate tol define a netfiow area therebetween, a portion of said adjustment needle being threadedly connected with said housing means for positional adjustment, whereby a thrust'plattern on said pump piston is governed to predetermine an initial pressure-time pattern in said pump chamber.

10. A pressure pump comprising wall means, a pump cylinder extending from a first side of the Wall means and cooperating therewith to define a pump chamber, means defining an outlet opening in the pump chamber, a pump piston slidably positioned in the pump cylinder, a cylindrical pump housing coaxial with the pump cylinder and cooperating therewith and with said wall means to define a fiuid supply chamber, means for filling said pump chamber with fiuid from said supply chamber, a thrust column rigidly attached to the pump piston and extending through the Wall means, an actuator cylinder extending from a second side of the wall means and cooperating therewith to define a first pressure chamber, actuator housing means cooperating with said wall means and the actuator cylinder to define a second pressure chamber, a plate dening an orifice between the first 4and the second pressure chambers, an actuator piston rigidly att-ached to said thrust column, said piston being positioned in said first pressure chamber and confronting the plate, a resilient seal between the actuator piston and the plate for effecting pressure sealing therebetween about said orifice, means for establishing a fluid setting pressure in the first pressure chamber to exert a force urging the actuator piston v 1'0 toward the plate to coverr'the' orificeand effect said .pressure sealing, and means forestablishing in the ,second chamber an actuating .pressure independent of said ysetting pressure yto act upon a portion of saidactuator piston Within -the resilient seal to overbalance said force and expose anV increased area of the actuator `piston to the actuating pressure, whereby thrust is exerted on said pump piston to produce output pressure in said pump chamber.

ll. A pressure generator according toclaim l0 and further including an adjustment needle. threadedly mounted on -said kbase member, a head portion on the adjustment needle, said head portion being ladapted for extension toward said plateV to define a netfiow area therebetween,-and means on the adjustment needle exterior of the pressure generator lfor selectively positioning said head portion to .predetermineV said `flow area, whereby a thrust-time pattern on said pump piston is governed to predetermine an initial pressure-time pattern in saidpump chamber.

12. A pressure pump comprising wall means, a pump cylinder extending from a first side of the Wall means and cooperating therewith to define a pump chamber, means defining an outlet opening in the pump chamber, a cylindrical pump housing coaxial with the pump cylinder and cooperating therewith andfwith said wall means to define a fiuid supply chamber, means for filling said pump chamber with fiuid from said supply chamber, a pump piston slidably positioned within the pump cylinder, a thrust column attached to the pump piston and extending through the wall means, an actuator cylinder extending from a second side of the wall means and cooperating therewith to define a first pressure chamber, actuator housing means` cooperating with said wall means and the actuator cylinder to ,define a second pressure chamber, a plate dening an orifice between the rst and the second pressure chambers, an actuator piston attached to the thrust column, said piston being positioned in said first pressure chamber andV confronting the plate, sealing means positioned between the actuator piston and the plate for effecting pressure sealing therebetween about said orifice, means for establishing a setting pressure in the first pressure chamber to exert a force urging the actuator piston toward the plate to cover the orifice and effect said pressure sealing, means for establishing -in the second chamber an actuating pressure to act upon a portion of said actuator piston within the sealing means to overbalance said force and expose ari-increased area of the actuator piston tothe actuating pressure, and an adjustment needle for restricting the release of the actuating pressure against the actuator-'piston upon said overhalancing of the setting force to disengage said sealing means, said adjustment needle having a head portion for extension toward said orifice plate to define a net fiow area therebetween, a portion of said adjustment needle being threadedly connected with said housing means for positional adjustment, whereby a thrust pattern on said pump piston is governed to predetemline an initial pressure-time pattern in said pump chamber.

13. A pressure generator comprising means defining a pump chamber disposed on a first side of a wall, outlet opening in said pump chamber, a pump piston slidably positioned within the pump chamber, a thrust column rigidly attached to the pump piston and extending through an opening in said wall, coaxial outer and inner actuator cylinders, each of the cylinders being closed at a first end thereof by a second side of said wall to define a pressure chamber between the cylinders, a plate defining an axial orifice at a second end of the inner cylinder, a base member closing a second end of the outer cylinder, said base member cooperating `with the orifice plate to define at least one passage communicating ybetween said pressure chamber and the orifice,'an actuator piston rigidly connected with said thrust column and positioned within the inner cylinder in confronting relation with said orifice plate, resilient sealing means positioned between the actuating piston and the plate for eiecting pressure sealing therebetween about said orifice, means for establishing a fluid setting pressure in the inner cylinder for exerting a force urging the actuator piston toward the plate to cover the orifice and effect said pressure sealing, and means for establishing in the pressure chamber an actuating pressure independent of said setting pressure to act upon a portion of said actuator piston within said resilient sealing means to overbalance said force and expose an increased area of the actuator piston to the actuating pressure, whereby thrust is exerted on said pump piston to produce output pressure in said pump chamber.

14. A pressure generator according to claim 13 and further including an adjustment needle for restricting the release of the actuating pressure against the actuator piston upon said overbalancing of the setting force to disengage said sealing means, said adjustment needle having a head portion for extension toward said orifice plate to define a net ow area therebetween, a portion of said adjustment needle being threadedly connected with said housing means for positional adjustment, whereby a thrust pattern on said pump piston is governed to predetermine an initial pressure-time pattern in said pump chamber.

15. A pressure generator comprising wall means, a cylindrical pump housing abutting the wall means, a pump case disposed coaxially within the pump housing and abutting the wall means, said pump case having a head portion deiining an outlet opening, the pump case and the cylindrical pump housing cooperating to define a supply chamber closed by an end member, the pump cylinder having at least one opening for receiving fluid from the supply chamber, an actuator cylinder extending from the lwall means and cooperating therewith to dene a irst pressure chamber on the side of said wall means opposite from the pump chamber, actuator housing means cooperating with the wall means and the cylinder to define a second pressure chamber, a plate defining an orice between the rst pressure chamber and the second pressure chamber, an actuator piston slidably positioned in the actuator cylinder and confronting the plate, a thrust column rigidly interconnecting -the pump piston and the actuator piston through the wall means, sealing means positioned between the actuator piston and said plate for effecting pressure sealing therebetween about said orifice, means for establishing in said first pressure chamber a uid setting pressure for exerting a setting force urging the actuator piston toward the plate to cover the orice and eect said pressure sealing, and means for establishing in said second pressure chamber an actuating pressure independent of said setting pressure to act upon 12 a portion of said actuator piston within the sealing means to overbalance said force and oppose an increased area of the actuator piston to the actuating pressure, whereby thrust is exerted on said pump piston to produce output pressure in said pump chamber.

16. A- pressure generator comprising wall means, a cylindrical pump housing abutting the wall means, a pump case disposed coaxially within the pump housing and abutting the wall means, said pump case having a head portion delining an outlet opening, the pump cylinder and the cylindrical pump housing cooperating to define a supply chamber closed by an end member, the pump cylinder having at least one opening for receiving tiuid from thesupply chamber, a thrust column attached to the pump piston and extending through an opening in said wall means, coaxial outer and inner cylinders, each of the cylinders being closed at a first end thereof by a second side of said wall means to detine a pressure chamber between the cylinders, a plate defining an axial orifice at a second end of the inner cylinder, a base member cooperating with the orifice plate to dene at least one passage communicating between said pressure chamber andthe orice, an actuator piston connected with said thrust column and positioned within the inner cylinder in confronting relation with said orice plate, sealing means positioned between the actuating piston and the plate for effecting pressure sealing therebetween about said oriice, means for establishing a setting pressure in the inner cylinder for exerting a force urging the actuator piston toward the plate to cover the orifice and effect said pressure sealing, means for establishing in the pressure chamber an actuating pressure to act upon a portion of said actuator piston within said sealing means to overbalance said force and expose an increased area of the actuator piston to the actuating pressure, and an adjustment element selectively positionable relative to said plate for predetermining a net ow area therebetween, therebyproviding predetermined restriction to release of said actuating pressure to said actuator piston upon said overbalancing of said setting force to disengage said sealing means, whereby a thrust-time pattern on said pump piston is governed to predetermine an initial pressure-time output pattern.

References Cited in the tile of this patent UNITED STATES PATENTS