US2549474A - Valve mechanism for hydraulic power presses - Google Patents

Description

April" 17', 1951 B. JAPiKSE VALVE MECHANISM FOR HYDRAULIC POWER PRESSEST 3 Sheets-Sheet 1 Filed Janr 25, 1943 April 7, 1951 V 5.. JAP-rKsE: i5 47 VAT-NE MECHANISM FUR HYDRAHEIG POWER PRESSE'S Filed Jan." 25, 1943 3 Sfiaeis+$heei 2 Patented Apr. 17, 1951 UNITED STATES TENT OFFICE VALVE MECHANISM role HYDRAULIC POWER PRESSES 7 Claims.

' This application is a continuation-in-part of my copending application Serial Number 454,168, filed August 8, 1942, for Valve Mechanism, now abandoned.

The invention relates to a hydraulic power press and more particularly to a selectively controlled means for controlling the action of a movable platen thereof.

The general object of the invention is to provide operating means which serves to prevent a lowering action of a movable mechanism before the driving mechanism has attained a predetermined speed or before the proper controls have become effective, to thereby'prevent a sudden lowering or dropping action or movement of the movable platen while the press is in operation.

A further object of the invention is to provide 7 control means in a hydraulic power press whereby a movable platen-can be restrained at a predetermined position during its downward travel or movement and in this manner cause the platen to be lowered at high speed 'prior to the actual initial pressing operation.

Another object of the invention is to provide control means in a hydraulic power press where- 'by'a movable platen remains comparatively reprovide, in a hydraulic power press, a valve mechanism for positively controlling the flow of fluid pressure from or to pullback cylinders.

Another detailed object of the invention is to provide, in a hydraulic power press, a valve mechanism so arranged. and constructed that when the power or electrical energy is cut off from the press the valve mechanism will be ac-. tuated or' energized to maintain fluid pressure in pullback cylinders to thereby prevent an unwarranted lowering action or pressing movement of a movable platen. I

The above, as well as numerous other objects,

will become apparent from the succeeding description considered together with the accompanying drawings wherein:

Figure l is a perspective more or less detailed view of a hydraulic power press embodying the present invention. 7

Figure 1A is a schematic view of the hydraulic power press shown in Figure 1.

Figure 2 is a vertical detailed view, shown partially in section and partially in elevation, of a valve mechanism forming a part of the present invention.

Figure 3 is a partial horizontal view and a par tial plan view taken along the lines 33 of Figure 2, looking in the direction of the arrows.

Figure 4 is a vertical sectional view taken along the lines 44 of Figure 2, looking in the direction of the arrows.

Referring now to the drawings in detail, wherein like numerals refer to like parts, the reference character A indicates, in a general manner, a hydraulic power press of the present invention. The hydraulic power press comprises a lower or stationary platen B having rising therefrom suitable columns C supporting at their up per extremities a top head cylinder casting D. Interposed between the top head cylinder casting and lower platen is a movable platen E arranged, through suitable mechanism hereinafter described, to be moved ina vertical direction toward and away from the stationary platen and guided through its range of movement by the columns. Mounted on one side of the top head cylinder casting is .a suction tank F forming a container for a source of supply of fluid employed in the operation of the hydraulic power press. Associated with the suction tank is an electrical motor G connected through a flexible coupling H to a high pressure hydraulic or main pump I With a gear pump J built therein. Coming out of the main pump at K is an outlet which is connected to a main cylinder L through a pipe M to deliver fluid under pressure to the main cylinder and urge an operating ram N out of the main cylinder. The operating ram is joined to or forms a part. of the movable platen so that any action of the operating ram will be reflected in the movable platen. Part 0 is the stroke control device of the pump and at location P of the vof breaking pressure, the pipe S serves to return the fluid over the main'piston in this valve back to the storage tank. Part T associated with the pilot relief valve is a hydraulic operated and spring-return pilot three-way valve; When the 4 pressure controlling the piston in the pilot relief valve shifts, a pipe line U functions as a drainage line to return fluid back into the surge tank. This oil or fluid will subsequently be returned fromthe surge tank 11." to the suction tank when sufficient excess oil has been discharged into the surge tank to cause it to over-flow over the bafiie plate U in the surge tank. The pres-- sure control piston (not shown) is built into the main bod of the pilot relief valve R. At V is indicated generally, a micro switch associated with the pilot relief valve which form a means or pressure tripping device for reversing the action of the movable platen.

Forming a part of the hydraulic power press is a valve mechanism generally indicated by the reference character i and termed, for. the sake of convenience, a pullback shut-off valve. This valve derives its fluid pressure through the pipe W connected to a port X of the main pump. The pullback shut-off valve has, leading in opposite directions therefrom, conduits Y which convey fluid pressure to adjacent lower extremities of pullback cylinders Z, the latter of which are spaced on each side of the press and are suitably anchored in the top head cylinder casting. Each pullback cylinder has a downwardly extending plunger Z projecting therefrom and which is securel fastened by any suitable means to the movable platen for the purpose to be hereinafter explained.

The valve mechanism or pullback shut-off valve'comprises a casing or body portion 2 preferably of rectangular lormation in horizontal cross section and having conveniently spaced thereabout on what might be considered as a front face 3 thereof, mounting taps for the accommodation of bolts or any other means (not shown) which retain the mechanism is assembled relation with the hydraulic power press. In Figure l of the drawings it will be noted that this valve mechanism is set out in spaced relation from the suction tank. However, this relationship has been illustrated merely for the sake of convenience because in actual practice the valve mechanism is anchored to or mounted upon the suction tank or other convenient location. Extending entirely through the casing intermediate the height thereof is a circular cross-port or passageway 5 presenting ports 6 at each side face I of the casing with the ports arranged for the accommodation of any means or an extremity-of the conduits Y which, as previously stated, are connected at all times to the operating sides of the pullback cylinders. Coaxial with an axis of the valve mechanism indicated by the diagrammatic line -4 in Figure 2, is a cylindrical chamber 8 extending away from and in communication with the cross-port or passageway 5. The chamber extends from the limits of the cross-port to the adjacent extremity of the casing where it merges into a seriesof slightly .enlarged counterbores 9 presenting a stepped ararngement or a shoulder ii] facing outwardly of the casing. Associated with the one extremity of the casing is a cap or end closing piece H firmly and removably secured to the casing through the medium of suitable holding means or bolts 52. The cap is provided with an outstanding stepped collar l3 formed to be neatly accommodated by the enlarged cylindrical bores and presenting a shoulder Id disposed oppositely and spaced from the shoulder It. interposed between the shoulders of the casing and the cap is a ring-like gasket i5 of any suitable material to present a leak-proof seal and prevent the escape of fluid from the chamber.

Arranged to move within the chamber in response to fluid pressure derived from a source hereinafter identified is a check valve it having position, extends through the passageway for its.

a body portion ll neatly accommodated by the chamber and being provided with circumambient grooves I8 facing outwardly and radially of the body portion for the reception of rings or an nular members [9 bearing against the chamber defining wall so as to prevent the escape of fluid from the chamber to the passageway and from the passageway to the chamber. The check valve has a reduced portion or neck 20 forming the one extremity thereof and which, in illustrated full length and terminates in an outwardly facing inclined seat 2|. The seat 2| is arranged to selectivel bear against a correspondingly inclined and disposed seat 22 formed on the casing and defining one limit of the chamber so that when the seat 2! is in contact with the seat 22 as illustrated, fluid may be arrested from escaping from the passageway and hence the conduits Y and pullback cylinders Z; Formed'in one face of the casing or body is a circular shallowmouth 2'3 having leading therefrom a channel. 24 which communicates with one limit of the chamber in the area adjacent the inward surface of the cap. Conveniently spaced about the mouth but removed therefrom are a plurality of tapped openings (not shown) for the accommodation of mounting bolts to retain a fitting or fixture I) over the mouth. Leading from the fixture o is a pipe 0 which is in communication with a three-way hydraulic pilot valve (1. Associated with the pilot valve is a solenoid e. By the tripping of suitable controls (not shown) the solenoid e may be energized to result in the pilot valve being operated to permit the, fluid beneath the check valve and cap to escape out of the mouth 23 through the pipe 0. and pilot valve to a connecting pipe (2' and enter the suction tank, thus bleeding the fluid from beneath the check valve and cap and permitting the latter to move toward the cap and thus carry the seat 2! away from the seat 22. There is now available at this time a pullback pressure against area 6| which develops a pressure equal to this area times the pullback pressure and which, therefore, drives the check valve positively away from the seat. Leading into or out of the cross-port or passageway 5 is an-angularly disposed port 25 which, through the medium of a pipe is in communication with a suitable part of the solenoid operated three-way hydraulic pilot valve (1 which is so arranged that when the solenoid e is deenergized port 25 is in direct communication with the mouth 23 leading to between the check valve and cap. Because of this arrangement when the electrical energy fails, which might otherwise cause a sudden drop of the movable platen, port 25 is connected with the mouth 23 and the pressure caused 'in the passageway, due to the weight of the movable platen hanging upon the pullback pistons is, through port 25, three-way hydraulic pilot valve, mouth '23 and channel 2d, adapted to act upon the lower exposed area of the check valve lBto urge the seat 2! into bearing relation with the seat 22 and thus entrap the fluid pressure within the pullback cylinders. This series of events will prevent an unwarranted downward action or movement of the movable platen since there is a positive forward force driving the check valve 16 against the seat 22 and the only opposing force is that of the pullback pressure acting against the smaller combined areas 6! and 52 and subsequently only against the still smaller annular area 6! alone as hereinafter explained in more detail. The areas acted upon by the pullback pressure are so proportioned that the differential between these forces is greater than the spring 52, hereinafter referred to in more detail, and for this reason the check valve is held closed as long as the solenoid e is not energized and this is also the case when the main pump motor is not operating or when certain other controls are not functioning as hereinafter described.

So as to prevent an excessive pressure being built up in the pullback cylinders when the fluid is entrapped therein, there is provided a duct 26 angularly disposed to and extending into the casing or body from one face 21 thereof to the interior of the casing, Where it communicates directly with the passageway. Leading from the duct 26 is a line 9 which is connected to a relief valve n, the latter being arranged so as to be selectively in communication, through the medium of a line i, with the suction tank. The relief valve n is installed in the circuit in the first instance to function as a safeguard on the pullback system.

That is to say, if for example the solenoid e should fail to operate after the motor has started and the movable platen is forced downwardly by the actuation of certain controls designated as 7" to pressing position, full pressure will be built up over the operating ram and the full press tonnage will be exerted on the pullback cylinder plungers Z. Accordingly, an abnormal pressure will be therefore built-up in conduits Y which will cause failure of some part of the system at naturally its weakest part. To prevent damage of any nature resulting from the above possible contingency the relief valve n is adjusted to blow off or becomeactuated when subjected to a 'predesignated pressure value which is well in excess of the pressure required to raise the movable platen but however sufliciently low to protect the system against damage in case of the failure of the solenoid e.

To further complete the assembly of fluid connections to the valve casing there is provided a head 28 removably secured to the casing or body by means of threaded elements or bolts 29 which extend through the head and into the casing. In

- alignment with the chamber on an axis of the valve mechanism is a. canal 30 of less diameter than the chamber and extending away from the seat 22 through the casing to terminate in an angularly disposed inlet 3| projecting to or through one face 32 of the head where it merges into a suitable conduit 33. The juncture between the casing and head in the proximity of the canal is of stepped design so as to present opposing shoulders 34 between which there is interposed a suitable packing ring 35 of any desired nature. The

stepped arrangement and packing ring forms a leak-proof juncture between the casing and head to prevent the escape of fluid at this location. Port 3| of the pullback shut-off valve is, as previously indicated, connected through the medium of the conduit 63, to a pullback port k on the pump so that when the pump is delivering fluid into this port pressure will be developed against an exposed end area 62 of the check valve iii to urge the check valve seat 2! away from the seat 22 or if the check valve is already in the latter named position the fluid pressure will be free to flow from the passageway 39 into the cross-port or passageway 5 and pipes Y to the operating end of the pullback cylinders for the purpose of rais ing the movable platen. If conditions are such that the movable platen is being lowered for a pressing operation then a reverse flow of the fluid will take place between the pullback cylinders and pump through the pullback shut-01f valve. The

; the'small area 52 of the check valve 13 to over come the closing force and open this valve suffi- V ciently far enough so that the pump delivery can be forced into passageway 5 and hence to the pullback cylinders, thus causing the movable platen to be raised but not lowered so long as the solenoid c has not been energized. When the solenoid e is subsequently energized by the tripping of suitable controls (not shown) the mouth 23 is connected by an action of the three-way valve d to a drain line d which returns any fluid in channel 24 to the suction tank. The line f leading from the port 25 is shut off in the threeway valve when this valve has shifted in this manner and the closing force upon the check valve I6 is-thereby eliminated while the check valve is opened by the action of the hydraulic pressure against the area 6 5. Under certain conditions the pressure on the pullback cylinders will always hold the shutoff valve open which is almost always true during those pressing operations where the material being pressed yields but very little. However, when the material being pressed is veryresilient, thus causing a long delivery stroke under main cylinder pressure and in such instances when the movable platen has contacted the work it is then supported by the work and the pressure on the pullback cylinders has van ished completely, so much so, that as a matter of fact, the pump may at that time create a slight suction on the pullback piping. If provisions hereinafter described were not made the arrangement of the pullback shut-off valve thus far de scribed would lack a definite or positive force to prevent the check valve it from seating against or contacting the seat 22 and experience has taught-that this closing action of the check valve actually would take place. After the check valve has seated and the movable platen has advanced further down during a continuation of a pressing stroke a slight amount of fluid will be expelled out of the pullback cylinders'which will cause the check valve to move away from the seat 22 and allow this fluid to escape past the seat 22 into the canal 30 and when lifting pressure has been released the check valve will again seat itself thus causing a continual pounding of seat 2| against seat 22 which eventually will cause damage to the seats because of this hammeringaction. -To thus eliminate this possible unwarranted action it has been found necessary to provide a definite force to hold the check valve open during this operation of the cycle.

As exemplary of such a definite force there is provided in the pullback shut-off valve a plunger 35 having a. head 3] thereof interlocked with or positioned in arear of an inwardly directed lip 38 on the reduced portion or neck. Locking the head in position against the lip 38 is a plug or rotatable element 39 extending into and threadedly associated with the check valve and having a gasket 40 sealing the juncture between the plug and check valve to prevent the leakage of fluid from the valve to the chamber. Associatijuncture.

'tains the sleeve in a predetermined fixed position. .A packing ring M is interposed between confronting shoulders 45 on the sleeve and head to prevent the escape of fluid from the canal at this The sleeve of less diameter than the accommodating canal is of tubular formation and accordingly, is provided with an axial bore 46 which extends entirely therethrough. 'The por tion of sleeve below the packing ring 44 is of stalk-like formation to form an unbalancing cylinder 4? to be disposed in parallel spaced relation to the wall defining the canal and thus allow the free flow of fluid from the pump to the exposed surface 62 of the check valve. In order to maintain the unbalancing cylinder in a fixed within the unbalancing cylinder bore to react against an inner shoulder 53 in the stalk and the free extremity 54 of the plunger.

If the valve mechanism were merely equipped with the check valve l6 and spring 52, but stem 50, plug as and the unbalancin cylinder were not installed, it would be impossible to retain the valve closed by applying pullback pressure to the port 25, three-way valve d and mouth 23, as the opening force would exceed the closing force by the amount of the spring pressure. has, therefore, and for reasons stated on page 8, lines l5 to 2!, been found necessary to diminish the force which tends to hold the check valve open and this is accomplished by reducing the exposed area of the check valve by the introduction of the unbalancing cylinder. As previously indicated, the cylinder bore 5! is merely slightly greater than the stem 50 so that a rather eiTective seal is obtained which prevents fluid from leaking profusely out of the canal so between these parts. There is, however, an extremely slight amount of leakage between the unbalancing cylinder and stem which is carried out through the restricted opening 55 in communication with a line m to the suction tank. To

prevent hydraulic binding, due to the long area of contact between the surface of stem 50 and the unbalancing cylinder 4'! a plurality of circumambient grooves 57 are formed inthe stem.

When the valve mechanism now describedis opened and it is desired to close the same by deenergizing the solenoid e the closing force equals the entire area of the check valve 16 times the available hydraulic pressure in the pullback system. This, of course, is counteracted by the remaining opening forces which are equal to the full area of the check valve is less the area of *the stem or unbalancing cylinder multiplied by the pullback pressure to which of course must be added the value of the spring 52. If the cross sectional area of the stem or unbalancin cylinder is made sufliciently large that its area times the pullback pressure is well in excess of the spring pressure it will then be appreciated that there is obtained a definite closing force which will cause the check valve to seat instantly when the electrical energy is cut ofl to deenergize the solenoid e.

Leading'to thecanal 30 through the body portionata position between one extremity of the 3 bodyand the plane of the passageway is a port 56 which is in communication witha surge valve 41' within a surge tank 11 through a pipe 0 so that upon a downward action of the movable platen during a pressing operation some of the fluid enterin the valve will bypass through the port 56 to the surge valve and thereby provide-a pilot pressure which will permit a rapid prefllling of the press main cylinder as the movable platen approaches the work.

The press is equipped with a slow-down device p which comprises a standard q secured to and depending a predetermined distance below the top head cylinder casting. The standard has mounted on the lower extremity thereof a snap-acting limit switch 1- forming a part of the electrical circuit of the press. Mounted on the movable platen and arranged to pass and contact the limit switch is a dog .9 so that when the movable platen has been lowered to a position where the limit switch is tripped, solenoid e is deenergized and the pullback shut-off valve is closed immediately, thus making it necessary to pump the movable platen downby building up pressure over the operating ram N and the pressure in the pullback system is then limited to the setting of the relief valve 11..

After the movable platen has been returned to the point where the snap switch 7 has been reset, solenoid eis again energized and the pullback shut-on valve acts again in the usual .manner. When operatin the pullback shut-off device in this manner it can thereiorebe used very advantageously to not only slow down the movable platen just prior to striking the work and thereby reduce the impact of contact which in some instances might be sufficiently severe to cause the material or work on the stationary platen to jar out of a predetermined position, as well as to prevent impact or subjecting the press to abnormal shocks when the die breaks through the work during the performance of either a blanking, cupping or drawing operation.

From the above it will be noted that various changes and alterations may be made to the illustrated and herein described construction without departing from within the spirit of the invention and scope of the appended claims.

I claim:

1. In a valve mechanism, a body having a crossport extending therethrough, a chamber perpendicularly disposed to and communicating with said cross-port, a canal in alignment with said chamber and communicatin with said cross-port for the admission of fluid thereto, a check valve in said chamber arranged to arrest the flow of fluid passing from said canal to said cross-port upon the introduction of fluid pressure to said chamber against one end of said check valve, and unbalancing means for reducing the exposed area of the other end of said check valve, said unbalancing means comprising a sleeve fixed with respect to said body and projecting into a recess in said other end of said check valve, and a piston carried by said check valve and received in said sleeve.

2. In a valve mechanism, a body having a passageway extending at all times uninterrupted therethrough, a chamber perpendicularly disposed to and communicatin with said passageway, a canal in alignment with said chamber and communicating with said passageway for the introduction of fluid to said passageway, a check valve in said chamber arranged'to arrest the flow of fluid from said canal to said passageway upon the introduction of fluid pressure to said chamber against one end of said check valve, an unbalancing cylinder disposed within said canal centrally thereof and associated with said check valve to reduce the exposed area of the other end of said check valve, said unbalancing cylinder comprising means extending into said canal in spaced relation thereto, and means outstanding from said last named means for maintaining said unbalancing cylinder in a predetermined position.

3. In a valve mechanism, a body having a passageway extending uninterrupted therethrough, a chamber perpendicularly disposed to and communicating with said passageway, a canal in alignment with said chamber and communicating with said passageway for the introduction of fluid from said canal to said passageway, a check valve in said chamber arranged to arrest the flow of fluid from said canal to said. passageway upon the introduction of fluid pressure, to said chamber against one end of said check valve, an unbalancing cylinder disposed within said canal, means fixed to and outstanding from said check valve fitting neatly within said unbalancing cylinder and resilient means reacting against said unbalancing cylinder and outstanding means.

4. In a valve mechanism, a body having a passageway extending uninterrupted therethrough and a chamber angularly disposed to and leading from said passageway, a cap closing one end of said chamber, a head mounted upon said body, a check valve within said chamber arranged to move therein and selectively arrest the flow of fluid to said passageway, a canal within said head and body for the accommodation of said fluid and leading to said passageway in alignment with said check valve, a sleeve removably carried by said head and extending into said canal, said sleeve having an aperture extending therethrough communicating with said canal, a plunger carried by said check valve extending into said aperture, and spring means reacting against said sleeve and plunger.

5. In a valve mechanism, a body having a passageway extending therethrough and a chamber angularly disposed to and leading from said passageway, a cover closing one end of said chamber, a head mounted upon said body. a check valve within said chamber arranged to move therein and selectively arrest the flow of fluid in said passageway, a canal within said head and body for'the accommodation of said fluid and leading to said passageway in alignment with said check valve, a sleeve carried by said head and extending into said canal, fin means on said sleeve abutting said body for maintaining said sleeve in fixed position within said canal, and resiliently actuated plunger means carried by said check valve and disposed within said sleeve in closely fitted relation thereto. Y

6. In a valve mechanism, a body having a passageway extending entirely therethrough and leading in opposite directions, a chamber normal to said passageway, a canal in alignment with said chamber and communicating with said passageway for the introduction of fluid to said passageway, a check valve in said chamber arranged to arrest the flow of fluid from said canal to said passageway, a port in said body for the admission of fluid to said chamber for effecting said check valve arresting action,

means carried by said body extending into said canal and in axial alignment with said check valve, means carried by said check valve and extending into said body carried means, and spring means within said body carried means for carried means.

7. In a valve mechanism having a passageway extending through a wall thereof, a chamber angularly disposed relative to said passageway and open at all times thereto, a canal in alignment with said chamber and communicating with said passageway for the introduction of fluid to said passageway, a check valve in said chamber arranged to arrest the flow of fluid from said canal to said passageway upon the application of fluid pressure against one end of said check valve, and unbalancing means for reducing th exposed area of the other end of said check valve, said unbalancing means comprising a sleeve fixed with respect to said body and extending into said canal in spaced relation thereto, and a piston carried by said check valve and slidable in said sleeve.

. BERTRAND JAPIKSE.

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

UNITED STATES PATENTS Number Name Date 564,167 Thompson July 14, 1896 912,022 OBrien Feb. 9, 1909 1,136,211 Collin Apr. 20, 1915 1,777,611 Grohek Oct. 7, 1930 2,020,773 Ernst Nov. 12, 1935 2,136,952 Ploen Nov. 15, 1938 2,148,543 Dinzl Feb. 28, 1939- 2,227,629 Cannon Jan. 7, 1941 2,304,634 Ernst Dec. 8, 1942 FOREIGN PATENTS Number Country Date 214,468 .Great Britain Apr. 24, 1924 409,391

Great Britain May 3, 1934

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