US 2618930 A
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Description (OCR text may contain errors)
Nov. 25, 1952 c, QUINN 2,618,930
LOW PRESSURE INTENSIFIER FOR HYDRAULIC PRESS OPERATION Filed July 7, 1950 ll upum I mews/wax CL VE MALVIN qmm 2 M M r AGEN S Patented Nov. 25, 1952 LOW PRESSURE INTENSIFIER FOR HYDRAULIC PRESS OPERATION Clive Malvin Quinn, Brighton, Victoria, Australia Application July 7, 1950, Serial No. 172,414 'In Australia July 14, 1949 Claims.
This invention relates to hydraulic presses employed for the moulding or forming of objects or articles from mouldable materials, such as, for instance, plastics, or the bending or shaping of materials.
Hydraulic presses for production of moulded or formed articles, comprise in general, a cylinder, a ram fitting the cylinder and carrying a table or movable platen whereon is mounted a mould section or die movable by the ram and co-operating with a fixed mould section or die mounted on the fixed platen or entablature of the press.
In order to charge the mould with material or locate a piece to be formed between the dies, it is necessary for the ram to have a relatively long stroke to separate the movable platen sufficiently from the fixed platen or entablature.
Hydraulic presses of the type indicated are commonly used in factories in association with a source of high pressure liquid for the manufacture of a variety of goods or articles, the high pressure liquid being commonly generated by powerdriven hydraulic pumps.
The principal object of this invention is to provide an effective system for operating a hydraulic press when motive fluid is available only at a low pressure, e. g., 100 lbs. per square inch, for the press operation.
A further object is to provide an efficient and comparatively inexpensive apparatus whereby the operation of the press in accordance with the invention may be carried out in practice.
In achieving the above stated principal object and accordin to the invention, a method of operating a, hydraulic press of the type specified consists in utilising a low pressure fluid to apply pressure to a press-operating liquid for impelling the ram at relatively fast rate against low resistance, and maintaining the pressure of said fluid upon the press-operating liquid so that upon increased resistance opposing movement of the ram the pressure of said liquid is automatically intensified to continue movement of the ram at lower speed against the increased resistance.
Conveniently, in thus actuating the press, the low pressure fluid is applied to a relatively large area of a volume of the press-operating liquid to supply the latter to the press cylinder at relatively low pressure to impel the ram at the fast rate, and upon the ram encountering the increased resistance utilising the pressure exerted by the low pressure fluid upon the relatively large area to apply a differential pressure to a relatively smaller area of a separate volume of the press-operating liquid to force the latter into the 2 press cylinder at intensified pressure to move the ram against the increased resistance.
Theplaten or head of the ram may carry a movable mould or die section wherein or whereon the work to be moulded or shaped is placed and which is co-operable with a fixed mould or die section supported on the fixed platen or entablature of the press. In operation and under action of the low pressure fluid the ram through the medium of the press-operatin liquid is actuated at comparatively high speed to close the mould sections or engage the work on the movable die section with the fixed die section. The resistance to movement thus imposed upon the ram automatically elTects through the action of the low pressure fluid an intensification of pressure of the press-operating liquid whereby the total pressure or force upon the ram is greatly increased to complete the moulding or forming of an article or object.
The low pressure fluid may be air delivered by a compressed air service, or alternatively, water under low pressure from supply mains, the former being preferable resultantly of its more rapid flow and speedy action.
In achieving the above recited further object of the invention, an apparatus for actuating a press by a low pressure service fluid, comprises cylinder charging means actuated by the low pressure fluid for supplying the press-operating liquid to the press cylinder at low pressure for moving the ram therein into mould or work engagement, and pressure intensifyin means operable by the low pressure fluid in response to mould or work engagement by the ram for increasing the pressure in the press cylinder to a high value to actuate the ram and complete a moulding or forming operation.
More specifically an apparatus for actuating a press by a low pressure service fluid, comprises a chamber of large cross-sectional area, a displacer in the chamber operable by the low pressure fluid, a chamber of small cross-sectional area associated with the chamber of large cross-sectional area and connected through valvular means with the press cylinder, a displacer in the large chamber having an extension within the smaller chamber, the space between the displacers being connected through valvular means with the press cylinder and this space and the smaller chamber containing press-operating liquid.
Upon admission of the service fluid to the larger chamber, the displacer operable thereby is moved to expel operating liquid from the space between the displacers into the press cylinder to move the ram therein to engage the mould sections or dies in the press, a flow of operating liquid from the press cylinder into the smaller chamber bein prevented by the valvular means.
Upon engagement of the movable and fixed mould sections or of the dies with a workpiece, the resistance to movement of theiraman'dthe pressure in the cylinder increases. Thereupon,
the low pressure fluid automatically actuates both displacers, and the extension of the displacer within the smaller chamber resultantly of the differential areas of the latter and the larger chamoer, increases the pressure within the smaller chamber to a degree sufficiently great for the completion of a moulded article or a formed piece. Upon the pressure increasing to-the required extent the valvular means is operated to admit the high pressure liquid from the smaller chamber to the press cylinder to complete the forming or moulding operation. The displacers may comprise resiliently yieldable members deformable by the low "pressure fluid, or alternatively, rigid members movable bodily under the action of the fluid.
I The accompanying drawing depicts one arrangementiof an apparatus for operating a press of the type specified.
Fig. :l is a semi-diagrammatic view in section of the above apparatus.
1Fig.i2.is a section taken on lineZ-2 of Fig. 1.
Fig. 3is a section on the line 33 of Fig. ,2.
Thezapparatus consists of a cylindricalcasing ficlosed'at each end by the cylindercoversor end plates I5 and l forminga closedcylindricalzchamher .8. Secured to the'end plate '6 and coaxial with the cylindrical casing 5 is a cylinder 9 of considerably reduced diameter e. g. .6 toil-reducjtionin diameter, the cylinder 9 being open at the bottom and closed at the top by the "plate 7 It.
I'Disposed within the cylindrical chamber ii are .a'pair of resilient members Ii and I2 composed of rubber or like'sheets and preformed to assume an inverted cup shaped form in the operativeposition as viewed in Fig. 1.
The :inner member I2 has a lesser mean diameterrelatively to the outer member I I- to thereby :provide a space therebetween forming a-recept-acle I3 for the reception of the press operating'1iquid,'in this instance a suitable'oil.
The major diameter of each resilient member I I 'and' i2 is :such that the sidewall of the member Hand mouth of the inner member -I2 have a diameter approximately equal to the diameter of the wall- 5 of the chamber 8. The members II and: I 2'arerespectively formed with circumferential marginal *rims it and I5 which .rims are clamped together between the flange 5a of the cylindrical'casing 5, and the lower end plate 1 by bolts la, as viewed in Fig. At approximately the'centrefihe end plate! is formed with aport Ma to "communicate'with the pipeIEa which is connected toa source of compressed air. through the three way-valve I6.
Therreceptacle 3 at :cneside is :arranged in communication with and connected toapressure oil supply pipe .Il, extending to the hydraulic pressindicated generally at IS.
.Inorder to connect the pipe I? with'the'receptacle i3, a'relatively thick ring Ila. i clamped between the rims i i and I5 of the members II and I2 by the bolts la and is formed with radial apertures I'Ib, seeF'ig. 3.
Secured to the ring i'ia by screws'tfl is a threaded aperture to which the pipe I! is screwed and accordingly connected by way of the aperture I'Ib with the receptacle IS. A check or nonreturn valve 2i is interposed in the pipe I! between the hydraulic press I9 and the casing 5.
Slidably fitting the chamber 8 and the small cylinder '9 is'a stepped piston comprising a larger "disc-like section 22 fitting Within the chamber 8 and an integral trunk forming a ram 23 slidable within the cylinder 9.
A quantity of pressure oil is provided in the small cylinder 9 above the ram 23, and is normally contained therein by the closure plate It. A central port 25 in the closure plate ID communicates with a pressure oil supply pipe 26 .which communicates with the branch pipe 2'! through'the spring loaded non return valve 29.
The branch pipe 21 is connected at one end tothe oil pressure supply pipe I? above the nonreturn valve 2|, so that pressure liquid may pass through pipe 26,.branch 27 and pipe I? into the hydraulic press 19. .Beyond the junction of the .pipezz'a withthebranch pipe 2? a valve 32isdis- .posed in the'latter.
In the positionshown in Fig. 1 the valve 32 will direct the flow of pressure oil to the hydraulic press through the'branch pipe i'l the other end Zia of whichis connected tothe oil receptacleithrough an apertured plate pressure oil from the cylin'der dfrom passing into the return portion of the branch pipe 321. .The hydraulic press I9 comprises; the cylinder- 38 containing a quantity of the pressure oil between the ram 39 fitting the cylinder and carrying a platen oriheadAll, upon which latter a-workpiece, die or'one section of a mould may be mounted to cooperate with a complementary part upon the'fixed platen (not shown).
In operation the valve 56 is adjusted to the position shown whereby compressed air enters the chamber IZafOrmed-by the'inner-member I2 which '-is expanded to therebyexert pressure upon and displace the oil in'the receptacle I3-to flow into'the pipes I1 and 21. '-Thevalve33 prevents the'displaced oil from passing up the'pipe 21 but the pressure is sufiicient-to overcome theresistance of the spring associatedwith'valve 2| whereby-the oil passes through" the. latter'into the cylinder 3B of the pressl9.
"The pressure of the ,oil' in the cylinder} 8 raises the ram 39 and platen'M] towardsthefixed platen or -.entablatu1',e (not .shown) and .upon engagementbeing effected betweenthe mould Darts, dies or work piece and diekresistance is setup to the movement of the, ram 39 .and-resultantlyto the flowof oil .fromreceptacle I3 through the pipe I'ito the cylinder 38.
Continued pressure exerted by the; pressure lair upon the inner member I 2. in the absence of-displacement of oil from the receptacle I3 causes the expansion of the member I-2: and;resultant displacement of the piston 22 and elevationof .the ram-23 in the small cylinder 9. The oil in the cylinder 9 is then forced pastthe .valve1'29, whichrequires a greater pressure than valve-ii to open, into and through the branch pipe 21 to the pipe I! and cylinder 38 of the press.
The relative diameters of the piston 22 and ram 23 are such that the pressure applied to the oil in the cylinder 9 for transmission to the press cylinder 38 responsive to the pressure applied to inner member i2, is such that the pressure is greatly intensified to move the ram 39 and platen 40 at a relatively slower rate against the increasing resistance set up by the operative engagement of the mould or die parts of the work piece with the die.
The intensified pressure of the operating oil in the press cylinder 38 achieves the completion of the moulding or die forming operation whereupon the pressure and the operating oil may be relieved to permit the ram 39 to return to the normal position. I i I To that end valve 32 and valve l6 are adjusted, and this may be achieved simultaneously by'a simple dual control arrangement, whereby the air pressure is relieved from the inner elastic member l2 and exhausted through the valve l9 into the branch [6a and atmosphere. Such a dual control arrangement for the simultaneous actuation of the valves 32 and I6 may comprise an arm 4| operatively connected to the valve 32, an arm 42 equal in length to the arm 4| and operatively connected to the valve [6, a handle extention 43 on the arm 4|, and a link 44 connecting the arms 4| and 42. It will be apparent that upon movement of the handle 43 and arm 4| through a quadrant, that is, an angular movement of 90, in the counter-clockwise direction, as viewed in Fig. 1, from the position illlustrated, the valve 32 will be moved to its fully open position for discharge of fiuid under the weight of the ram 39, and the valve (6 will be moved to a position shutting-off the supply of compressed air and simultaneously exhausting air from the chamber In through the pipe I5a and branch 16a to atmosphere. Simultaneously in the absence of the pressure exerted by the elastic members H and I2 the oil flows through valve 32 into the return bend of the branch pipe 21 to pass into the return pipe 35, and through the valve 31 to refill .the small cylinder 9. Simultaneously a quantity of the oil is passing down the branch pipe 21 through the valve 33 to re-enter the receptacle l3. Thus th oil initially displaced from the receptacle l3 and small cylinder is returned by the simple expediency of adjusting the two valves 32 and I6, the other valves being opened responsive to the pressure of the oil flow.
In the practical arrangement above described resilient cup-shaped members II and I2 are used to form a compressible space or receptacle for the press-operating liquid or oil, but it will be apparent that a floating piston may be fitted in the cylindrical casing and used in co-operation with the stepped piston or ram to charge the press cylinder with operating liquid and intensify the pressure of the liquid for the completion of a moulding or pressing operation.
1. A pressure intensifier for a hydraulic press comprising a receptacle, a first displacer in the receptacle movable by an operative fluid under pressure, valve means operable at will for admitting and exhausting the operative fluid to and from the receptacle to control the movements of said first displacer, a second displacer in the receptacle separated from said first displacer to provide a space for a press-operating liquid between said first and second displacers from which space the press-operating liquid is forced at low pressure -for utilization in a hydraulic press in response to relative movement of said first and second displacers, a pressure-intensifying receptacle, and a third displacer in the pressure-intensifying receptacle operatively connected to said second displacer and movable by the latter in response to increasing resistance to fiow oi press-operating liquid from said space between said first and second displacers for supplying press-operating liquid at high pressure from the pressure-intensifying receptacle to the hydraulic press.
2. A pressure intensifier for a hydraulic press comprising a casing, a first displacer in the casing movable by a low pressure operative fluid, manually operable valve means for admitting and exhausting the operative fluid to and from the casing to control the movements of said first displacer, a second displacer in said casing responsive to movements of said first displacer and separated from the latter to provide a space therebetween for a relatively low pressure liquid, a high pressure chamber, a third displacer in said high pressure chamber connected to and operable by said second displacer to intensify the pressure of a liquid in said chamber, inlet tubular system means for supplying the low pressure liquid from said space between said first and second displacers and the liquid under intensified pressure in said high pressure chamber to an hydraulic press, and tubular exhaust system means for returnin the liquid from the hydraulic press to said space and said high pressure chamber.
3. A pressure intensifier for a hydraulic press comprising a low pressure cylinder, a first displacer in said cylinder movable by an operative fluid under pressure, manually operated valve means for admitting and exhausting the operative fluid to and from said cylinder to control the movements of said first displacer, a second displacer in said cylinder responsive to movements of said first displacer and separate from the latter to provide a space for a relatively low pressure liquid between said first and second displacers, tubular means for conveying the low pressure liquid to a hydraulic press from said space between said first and second displacer an inlet valve in said tubular means for controlling the admission of the low pressure liquid to the hydraulic press, a pressure-intensifying cylinder, a piston in the pressure-intensifying cylinder operatively connected to said second displacer, a tubular conduit for connecting the pressure-intensifying cylinder with the hydraulic press, an inlet valve in said tubular conduit for controlling the admission of high pressure liquid from said pressure intensifying cylinder to the hydraulic press, a tubular system for returning liquid from the hydraulic press to said pressure intensifying cylinder and said space between the displacers, and valve means in said tubular system for controlling the exhaust of liquid from the hydraulic press through said tubular system.
4. A pressure intensifier for a hydraulic press comprising a tubular casing, a cover secured to each end of said casing, a first resilient dished member disposed at one end of said casing and defining conjointly with the adjacent cover a receptacle for an operative fluid, a pressure-intensifying cylinder on the cover at the opposite end of said casing, manually operable valve means for admitting and exhausting the operative fluid to and from said receptacle to efiect expansive movement and permit contractive movement of saiidifirstxesilient :dished member, a second ire- .silient dished member, in the casing separated from-said: first dished member to provide a space for a press-operating liquid between the first and second dished members from which space the press-operating liquid is forced at low pressure for utilization in a, hydraulic press in response to expensive movement of the first dished memcylinder and saidspace between'the dished mem- ..bers,-exhaust valves in the exhaust tubular system, and amanually actuated valve in said exhausttubular system operable to-connect said systems for discharge of press-operating liquid tosaid space and said cylinder.
5. A pressure intensifier for a hydraulic press comprising a cylinder flanged at each end, a cover secured to each ofv said end flanges, a pair of elastic cupped members disposed in said cylinder one within-theother, peripheral rims on said cupped members clamped by'and between one of said covers and the adjacent flanged end 'o-fthe cylinder, the inner cupped member defining with .said :one cover a; receptacle for compressed air and the outer cupped member being separated from said inner cupped member to define :a space forpress-operating liquid, a pressure intensifyingcylinderoi ,less diameter than the flanged cylinder :and mounted centrally on the other :cylinder .cover,;a pressure plate in said flanged within'said pressure intensifying cylinder, an inlet tubular system for connecting said pressure-intensifying cylinder and said space for press-0per ating. liquid with a hydraulic press, valve inlet means in said inlet tubular system, an exhaust tubular system for connecting said inlet tubular system with said pressure-intensifying cylinder and said space between the cupped members, valve exhaust means in said exhaust tubular system, a manually actuated valve in the exhaust tubular system operable to connect said systems for :discharge of press-operating liquid to said space and said pressure intensifying cylinder, tubular means connecting said receptacle with a compressed air supply, and a three-Way valve in said exhaust tubular system for controlling the supply and exhaust of compressed air to and from said receptacle.
CLIVE MALVIN QUINN.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 2,319,950 Schleicher et al. May 25, 1943 2,351,872 Parker June 20, 1944 2,403,912 Doll July 16, 1946 2,511,541 Purcell June 13, 1950 2,569,226 Carter Sept. 25, 1951