US2548784A - Pneumatically operated hydraulic press - Google Patents

Description

April l0, 1951 w. s. HANSEN PNUMATICALLY OPERATED HYDRAULIC PRESS 5 Sheets-Sheet 1 Filed March 22, 194e April 10, 1951 w. s. HANSEN 2,548,784

PNEUMATICALLY OPERATED HYDRAULIC PRESS Filed March 22, 1946 5 Sheets-Sheet 2 Q JQ 9 150 XM w 2 f K April 10, 1951 w. s. HANSEN PNEUMATICALLY OPERATED HYDRAULIC PRESS 5 Sheets-Sheei'I 5 Filed March 22, 1946 pril 10, 1951 w. s. HANSEN '2,548,734

PNEUMTICALLY OPERATED HYDRAULIC PRESS Filed March 22, 194e 5 sheets-sheet 4 April 10, 1951 w. s. HANSEN 2,548,784 y PNEUMATICALLY OPERATED HYDRAULIC PRESS Filed March 22, 1946 5 Sheets-Sheet 5 193 ,A SUPPLY 186 l/E l 7 V 186 A/IZ CLEANER g8 n; 56 lie 159 fuwgd' 1242 y ulllf l//M gs //ml y .9' /0 TQ' PQ-ASSUE MICRO/METER "G Hmmm? Tizi 'lA/'lill l l Il 5315? y STROKE pOSTDN/NG VALVE Patented Apr. 10, 1951 PN EUMATICLLY OYPUER'IED`.` HYDRAULIC BRESS.v

WaldenianS; Hansen, Cary, Illi, assig-Iioivto- Stew-1 art-Warner Corporation, Chicago, Ill..;a ;c.0r

porationA offVirginia Application March 22, 1946, Serial No. 656,1 198l M'y invention relates. generally to*4 hydraulic presses, and more'particularly-tocompressedair operatedY hydraulic: presses;

Unless a convenient'source of hydraulic pressurei is' available, hydraulic'- presses' are generally ineicientbecauseitisusually 'necessary `to maintain the hydraulic pressure duringthe intervalsn between' operations of the press; Thus; the* hydraulic pump; must" forpractical reasons;v run continuously, and` consumes power while the press is not* in actual operation. Furthermore, in many forms ofi'hydraulic presses the length` of the stroke and' the position of" the operating stroke relative tof theloedoftlie machine'are 'not conveniently adjustable, and, asa result, thesev pressesare frequently operated withV a stroke greater than requiredfor the particular operation beingperformed'.

In pneumatically operated presses, this condition usually prevails.. so thatv itisv foundA that the consumptionof compressed air is. much greater than that required to perform the particular operation. isdue, of course, to the fact: that in pneumatically operated motorsi of; the,l reciprocating typefthe same amount'of com-Y pressed air is. utilized in effecting, the fullstroke,

of the'y piston whetherV the piston. is operating against a, load or. not. Thus;` if. the required stroke of the plunger is less ,than theffulll stroke of the piston. ofitheairmotor, andthe air motor operates only througlrzitsiullstroke, it' isappar.- ent that the'apparatus is inefficient in. its consumption of compressedzair.

It is therefore an objectief my invention toM provide an improvedv hydraulic pressusing compressed air as` thel'm'otive power, in which. the extent and location ofr the strokerelative to the bed of the press-may.: be readilycontrolled.

A further objecti is-l tor`` provide an Vimproved.

hydraulic press in whichj the speed of the operating stroke may readily be adjusted.

A further Objectis toprovide an improvedhydraulic press having-a pneumatic actuator in which the stroke is manually-initiated by opening an air valve,` and'inlwhichthe strokev of a hydraulically operatedplunger is arrested by closing a valve in the hydraulic system.

Other objects `will appear from the following description, reference being had toy the accom-- panying drawings; in which:

Fig. l isv a front. elevational viewV ofthe press, showing the majorcomponents in central vertical section;

Figs; 2, 3, andl; are horizontal sectional views,

3 Claims; (Cl. GDF-54.5):-

Fig- 9- isa ragmentar-ysectional" view; taken Fig. 10 isa diagrammatic' View illustrating` the# hydraulic and-pneumatic circuits;

Asshown' in Figf 1;v the press-comprises-abase-A 20 having a pair of supportingA columns 212; secured thereto, these columnssupportinga head plateY 24 which is rigidly secured theretoby nuts- 26* threadedv over the ends of`^- the tie rods or columns? 22. An' air cylinder head1` 28-1-is'` rigidlya secured to the headl plate 24fby tie rods v30'; are tlfireadediny the platev 21|*` andi-also clampan'- air cylinder3'2between'the head 282 and plate 24;-

An air piston 3'4f` having alsealingc member'St' clamped thereto-"by aJ ring 38,v is-reciprocable, 'inthe cylinder-32'and'has`a piston'rod 40 extending freely through the head 28. TheL pistonrodlllnasa reduced upper end'portion'll around which' is` clamped an power piston 44: having af'plurality of 'sealing'rings 462 TheY piston illL is reciprocable in a power'cylinderA Mathe-upper endf'ofwhich-is;v closedby a headSU, the'heacl 50 beingsecuredtol the head 28v byva plurality-of tie bolts-52, the tie bolts clamping, the cylinder 48 in pla-ce; Sure"v rounding the cylinder 4-8" is" aN cylindricalsheet 54 which', togetherwith the Vouter walliofj the cylinderA 48;' formsta reservoir 56for;theyhydrauli'cf actuating fluid, the lower part ofl thereservoir being formed byl al1-annular plate 58""while-the upper end* is closed by a; sim-Har plate 611i Thev reservoir Eli-k may be. partially iillediwitlfi oil`v or other hydraulic actuatingliuuid'throughi,a fillerI opening normally closedby ia* plug 62':

The toolY carrying plungercomprisesaipiston'- rod 6l! having' amotor piston assembly 66 fsecrn'ec'i` thereto, the assembly c o'mprisingga' plurality of! sealing rings BBsuit-ably clamped to; the roclYi 6,11* and reciprocable in amotor cylin'der69. The rod dextends downwardlytlrrouglra head 10j which is secured to the plate 2'8-`r by a pluralityof tie bolts 12; and-'is` providedfwith a; packing;4 gland 14. Theflower end# oyf'theplunger2 rod 6l* is` provided withasocket, 16'? for the receptioxr of the tool or; fixture. Cla-mped `to the lower'endSk of the plunger rod 64 is a valve actuator comprising an elbow 18 (Fig. 3), one arm of the elbow 18 having a guide element 80 tting in a suitable groove 82 formed in one of the columns '22, thus preventing rotation of the plunger rod 64. The other arm of the elbow 18 has a bushing 84 secured thereto, this bushing having a vertical hole for the reception of a rod 86.

Upon the limit of the downward stroke of the plunger rod 64, the bushing 84 engages an adjustably positioned stop 88 which is clamped in adjusted position on the rod 86 by a screw 90. The rod 86 is guided in a bracket 92 suitably secured to the head plate 24 by one of several studs 98 which also serve to clamp to the head plate 24 hydraulic valve sections 98 and 99, suitable gaskets being provided to seal the joints between these parts. The valve section 99 is provided with a valve seat insert which is adapted to be closed by a valve |02, this valve having a stem |04 extending through a suitable packing gland |06 and having stroke adjusting nuts |08 threaded thereon. The rod |04 is secured to the rod 86 by a rigid coupling ||0 and the latter also serves as an abutment for a compressed coil spring |2, the lower end of which presses against the bracket 92. The valve |02 is thus spring impelled to open position, the degree of opening permitted being limited by the adjustment of nuts |08 to vary the space between the upper one of these nuts and the packing gland |06. The valve |02 is adapted to control the flow of oil from a pipe ||4 connected to the section 98, and an L-shaped passageway ||6 formed in part in the sections 98 and 99 and in the head plate 24. `The passageway ||6 communicates with a duct |18 formed in the plate 24. The passageway ||8 communicates with the upper end of the cylinder 66 (Fig. l). Y

A pipe |26 is connected to the lower end of the cylinder 66 (Fig. 1)*by its connection to a passagewayA |22 formed in the head 10. The pipe has an adjustable swivel connection with a pipe |24, these pipes being threaded in swivel sections |26 and |21, respectively (Fig. 5). The swivel sections are clamped together in adjusted position by a bolt |28 having conical sealing washers |29 engaging in complementary recesses formed in the ends of the swivel sections |26, |21. A sealing gasket |30 is provided to seal the joint between the two swivel sections. By tightening the nut of the bolt |28 the three seals provided respectively by the conical sealing washers |29 and the gasket, |30 are made tight at the same time.

The pipe |24 has its upper end threaded in a connector |82 (Fig. 4) which is welded to the cylinder 54, and the pipe thus communicates with the reservoir 56.

Compressed air is supplied from a suitable source through a pipe |34 (Fig. 4), and after passing through an air filter or cleaner |36, flows through a T |38 to an adjustable pressure regulator |48. An air line lubricator |42 receives the air from the pressure regulator and is connected to a T |44. One branch of the T has a pipe |46 connected thereto for an air pressure gauge |48 (Fig. 1), while the other branch of the T |44 is suitably connected as by a pipe |50 with an air control valve |52, shown in detail in Fig. 1. This air control valve comprises a body |54 having end caps |55 and |56 secured thereto by studs |58. The cap |55 has va seat therein for a double acting valve |60 carried by a stem |62. The valve |60-- is normally held inthe position shown in 4 Fig. '7, but upon operation of the suitably controlled treadle |64, is adapted to move away from the seat formed in the head |55 and engage a seat |66 formed in the valve body |54. The treadle |54 is connected to an operating rod |68 by any suitable means such as a cha-in |10, and is suitably secured to the stem |62, the valve being urged to its upper position by a spring |12 compressed between a iiange |14 formed on the rod |68 and a cross bar |16 carried by a pair of studs |18 (Fig. 8). When the treadle is depressed to move the valve |60 to its lower position, air under pressure supplied through the pipe |50 ows into the cavity formed in the valve body |54 and outwardly through a passageway |80 formed in theV head plate 24. As indicated in Fig. 1, the passageway communicates with the lower end of the air cylinder 32'. When the valve |60 is returned to its normal position by the spring |12, the passageway |80 is connected to a pipe |82, the pipe |82 having exhaust muilier or silencer |84 connected thereto.

The upper end of the hydraulic pump cylinder 48 has a pipe |86 suitably connected thereto, this pipe leading to a speed controlling adjustable needle valve |88, having a valve stem |89 locked in adjusted position by a lock nut |90.

The speedY control valve |88 is connected to the pipe I4 and also to a stroke positioning shutoff valve |92, the latter being connected by piping |94 (Fig. 4) with the pipe |24. Air under pressure supplied tothe T |38 passes a check valve' |96 and flows through a pipe |98 to the upper end of the reservoir chamber 56.

In operation, the cylinder 69 is completely illed with oil or other hydraulic operating uid, while the reservoir 56 is partially filled with oil. Assuming that the oil conduit system has been purged of air, the operation of the press is as follows.

As previously noted, thepoint at which the operative down-stroke oi" the plunger 64 commences, may be adjusted. Referring to Fig. 101, this is accomplished by opening the stroke positioning shutoff valve |92 and depressing the treadle |64 to open the valve |52. When the valve |92 is open, it will be clear that oil in the reservoir 55 under the pressure of the compressed air supply to which it is continuously connected, will ow through the pipes |24 and |94, stroke positioning shutoff valve |92, conduit ||4, stroke control valve |02, and passageway H8, into the upper end of cylinder 69. Due to the greater effective cross sectional area of the upperface of the piston 66, this piston is moved downwardly until it attains the position in which it is desired to start the normal downward operative. stroke, and at this position the Vvalve |92 is closed.

To adjust for the lower limit of the downward Y,

stroke of the plunger 64, the stop 88 is clamped to the rod 86 in such position that it is engaged by the bushing 84 and forces the valve |02 to closed position at the time that the plunger 64 reaches the desired lower limit of its stroke.

The press is now in condition to be operated, assuming that the proper tool or iixture has been secured to the plunger 64, and this is accomplished merely by pressing upon the treadle |64 to open the air supply valve |52. Air under pressure thus is permitted to flow through the passageway |80 into the lower end of cylinder 32,-

thereby forcing the connected pistons 34 and 44 upwardly and increasing the pressure of the oil in cylinder 48. The oil is thus forced to now, at a ratey controlled by the speedrcontrol valve|88,

through conduit-|14 andlcontroli-valve |92 intothe upper end of the cylinderf. The pistonlI the pressure of hydraulicfluidLon its top surface' overcomes the force of thespring- H2 andcompletes the closing movement, further compressing the spring I I2 and moving the stop 88 a short distance below the actuator 18.

When the downward stroke of the plunger 64 has been completed, the operator releases the treadle |64 to permit the return of the air ccntrolled valve |80 to its normal position, as shown in Fig. 7, thereby disconnecting the lower end of cylinder 32 from the compressed air supply and connecting it to the exhaust pipe |82, which permits the air to escape to the atmosphere through the silencer |84. Upon thus releasing the air valve, the oil in the reservoir 56, under the pressure oi the compressed air supply, is forced through pipes |24 and |20 into the lower end of the cylinder 69, thereby forcing the piston B5 upwardly. The oil in the cylinder 59 above the piston is forced past the valve IGZ, and through the pipe ||4 and speed control valve |88 and conduit |86 to the upper end of cylinder 48, forcing the pistons 44 and 34 downwardly. The valve |02 may be opened by spring ||2 because of the slight spacing between the stop 88 and the bushing 84 on the arm '18, which occurs when this valve is moved to its fully closed position. When the pressure is applied to the lower surface of this valve a considerable force is available to open the valve because at this time the pressure in cylinder 4B is negligible. When the piston 34 reaches the bottom of its stroke by contacting the head plate 24, the piston 65 has its upward movement arrested at the position for which the initial adjustment was made.

It will be noted that the air piston 34 is moved only a sufcient distance to supply the necessary oil under pressure to the upper end of cylinder 69 so that if the stroke of the latter is relatively short, the stroke of the air piston 34 will be correspondingly short. It will thus be seen that the minimum amount of compressed air required for a particular stroke of the plunger 64 is used, and this is accomplished even though the upper and lower limits of the stroke of the plunger 64 are readily adjustable to adapt the press for any particular operation it may be required to perform.

The press may be used for broaching, forming, and various pressing operations. In many instances the press will be provided with a suitably indexed table and the valve |52 arranged to be automatically operated, so as to make the press automatic in operation except for the requirement that the workman load unnished workpieces on the rotating index table and remove the iinished parts therefrom.

While I have shown and described a preferred embodiment of my invention, it will be apparent that numerous variations and modifications thereof may be made without departing from the underlying principles of the invention. I therefore's desire; by the-1 followinglf clairnsg. to' include within the scope of fthe-invention, all -sucliyaria-l t'ionsif and modifications byw-liicli` substantially;

the results of my invention'- mayA be obtained`V throughthe use of substantially the J vsame orf equivalent means. vIt will be understoodthat-thef words denoting' directionl or position, used-vini the-following claims,V arenot intended to -be in-Y terpreted in their absolute-senseA but-ratherV in= their: relative sense.

l. In a hydraulic press, the combination-,oa reciprocable hydraulic motor comprising, a motor cylinder, a motor piston, and a piston rod secured to thepiston and extending from the cyl-inder: to. apply pressurev to f workpieces, af; hydraulic power cylinder havingi aipiston;reciproi\ cable therein, an air cylinder, a piston reciprocable in the air cylinder and rigidly connected to the power piston, manually operable valve means for admitting compressed air under pressure to one end of the air cylinder, an oil reservoir, means for maintaining the oil in the reservoir under relatively constant pressure, a conduit connecting the oil reservoir with the lower end of the motor cylinder, a stroke control valve, a conduit connecting the stroke control valve in series between the head end of the power cylinder and the head end of the motor cylinder, means operated by the plunger upon traversing a predetermined stroke to close the control valve, a conduit connecting the head end of the power cylinder with the rod end of the motor cylinder, and a manually operable flow cutol valve in said last named conduit.

2. A pneumatically operated hydraulic press comprising, a frame, a hydraulic motor cylinder secured to the frame, a motor piston in said cylinder having a piston rod extending downwardly therefrom, an air cylinder and a hydraulic power cylinder secured to the frame in substantially axial alignment, a source of air under pressure, means operable at will for alternately connecting the air cylinder to the source of air under pressure and to the atmosphere, operativelyconnected pistons in said power cylinder and said air cylinder respectively, a conduit connecting the upper end of the power cylinder and the upper end of the motor cylinder, means in said conduit for controlling the rate of flow of hydraulic fluid therethrough, means for predetermining the aggregate volume of hydraulic iiuid contained in the upper ends of the hydraulic power and motor cylinders, thereby to predetermine the extent of upward movement of the motor piston and rod, valve means in said conduit, and means to move the valve means to closed position by the motor piston rod when the latter has moved downwardly through a predetermined distance.

3. In a hydraulic press, the combination of a reciprocable hydraulic motor comprising, a motor cylinder, a motor piston, and a piston rod secured to the piston and extending downwardly from the cylinder to apply pressure to workpieces, a hydraulic power cylinder having a piston reciprocable therein, an air cylinder beneath and in alignment with the power cylinder, a piston reciprocable in the air cylinder and rigidly connected to the power piston, manually operable valve means for admitting compressed air under pressure to one end of the air cylinder, an oil reservoir, means for maintaining the oil in the reservoir under relatively constant pressure, a conduit connecting the oil reservoir with the lower end ofthe motor cylinder, a stroke Control valve, a conduit connecting the stroke control valve in series between the upper end of the power cylinder and the head end of the motor cylinder, means operated by the plunger upon traversing a predetermined stroke to close the control Valve, and a manually operated valve and conduits connected between the head end of the power cylinder and the rod end of the motor cylinder, said last named valve being operative to control the aggregate volume of oil in the head end of the motor cylinder and the upper end of the power cylinder.

WALDEMAR S. HANSEN.

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

UNITED STATES PATENTS Number Number Name Date Gerdau Feb. 25, 1913 Burns May 28, 1929 Bath Aug. 13, 1929 Proell Sept. 8, 1931 Sciaky Mar. 30, 1937 Pendleton June 10, 1941 Ernst Oct. 14, 1941 Wheelon Aug. 11, 1942 Gray July 13, 1943 FOREIGN PATENTS Country Date France May 28, 1927

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