US2448852A - Control apparatus - Google Patents

Description

Sept. 7, 1948. s. AAMoT CONTROL APPARATUS 2 Sheets-Sheet 1 Filed Dec. 29, 1945 wei@ bw mit QW Vmli .wrllmwl e @e a@ a x X e nl Wm.

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s. AAMoT CONTROL APPARATUS Filed Dec. 29, 1945 2 Sheets-Sheet 2 l. L E.

' Arran/vir Patented Sept. 7, 1948 'UNITED sTATEs PATENT ori-ICE CONTROL APPARATUS Sven Aamot, Downers Grove, Ill., assgnor to Western Electric Company, Incorporated, New vYork, N. Y., a corporation of New York Application December 29, 1945, Serial No. 638,393

3 Claims.

This invention relates to control apparatus and more particularly to hydraulic control systems for selectively operating only a selected one of a plurality of hydraulic actuators.

An object of this invention is to provide a simplified and eiective control apparatus for selectively operating any one of a plurality of acu tuators.

In one embodiment of the present invention, there is provided a hydraulic system in which a pump, a multi-position operating valve, and a multi-position selector valve are connected in series and two hydraulic actuators are individually connected to the selector valve so that the selector valve may be actuated to select which of the actuators is to be actuated and the operating valve may be actuated to determine what kind of operation is to be imparted to the selected actuator. v

The invention will be more fully understood when considered in conjunction with the following specication and the appended drawings, in which:

Fig. 1 is a diagrammatic view of a hydraulic system for operating a mold lifting hydraulic actuator and a furnace tilting hydraulic actuator and showing a multi-position operating valve and a multi-position selector valve in the system each in neutral position;

Fig. 2 is a View of a portion of the hydraulic system shown in Fig. `1 with the operating valve in its lower position and the selector valve in its upper position; and

Fig. 3 is a View of a portion of the hydraulic system showing the operating valve in its upper position and the selector valve in its upper position.

The hydraulic system, which is used for raising and lowering a moldsupporting table III and for tilting a casting furnace I2, comprises a hydraulic pump I4,'a multi-position operating valve I6 hydraulically connected to the pump, a multiposition selector valve I8 hydraulically connected to the operating valve, and hydraulic actuators 20 and 22 for actuating the `mold supporting table and the casting furnace, respectively, individually hydraulically connected to the selector valve I8.

Mounted on the table lll are a plurality of elongated hollow molds 24 closed on all sides except at the top end, which is adapted toreceive a pouring spout 25 through which the mold is lled. .The mold supporting table I is mounted on the upper end of a cam 21 `mounted for reciprocation within the cylinder 28 of the hydraulic actuator and is movable verticallyto carry the molds from the pouring position shown in full lines in Fig. 1 to a mold unloading position shown in dot and dash lines in Fig. l. A single pipe 29 connects the lower end of thecyl- `inder 28 to an outlet port 30 of the selector valve I8.

The casting furnace I2 is supported in a pair of standards 33 and is adapted to be tilted about a pivot 34 at the upper end thereof. On either side of the casting furnace I2 and pivotally attached thereto at 35 is one of a pair of rams `36 mounted for reciprocation within a pair of cyl,- inders 38 of the hydraulic actuator 22. The cylinders 38 are pivotally mounted in bracketsv 39 supported on the base 48 of a pit in which the hydraulic actuators 20 and 22 are located. The cylinders 38 of the actutor 22 are connected by exible connections 4I to a single conduit 42, in turn connected to an outlet port 43 of the selector valve I8. The rams or pistons 21 and 36 of the hydraulic actuators 20 and 22 are moved upwardly from their normal positions by the inflow of fluid into the lower ends of the cylinders 2B and 38, respectively, under pressure from the pump I4 and under control of the operating valve I6 and the selector valve I8. rlhe rams 21 and 36 are returned to their normal position under the force of gravity and the outflow of fluid from the lower end of their respective cylinders under control of the valves I6 and I8. i l

The operating and selector valves are substantially identical and each comprises a bodymember 45 centrally apertured at 46 to form a valve `chamber' and is provided with heads 41 and 48 secured thereto. A piston type slide valve member 5Il, having three enlarged spaced heads 5I, 52 and 53, is reciprocably mounted inesaidval've member 46 and is provided with piston rod portions 54 and 55 extending in opposite directions through apertures in the heads 41 and48. The lower end of the valve rod .55 is reduced to form a shoulder 56 and is provided with washers 51 and 58 slidably mounted thereon. A compression spring 60 is interposed between the washers, and a pin 6I is provided in rod 55toretain the washer 58 in -a predetermined relation to thewasher 51, which normally seats against the shoulder 56. `A cup-shaped member 65, secured to the valve head 46, is provided with a seat 66 for the washer 58 and serves, in cooperation with the washers 51 and 58, the spring 6E), and the end surface oi -the head 48, to maintain the valve normally in a neutral position, as shown in Fig. 1. Pivotally attached to the upper end of the rod 54 is an operating lever 68, one end of which is slidably fulcrumed in an aperture 69 in the head member 41. The arrangement of the spring 6G and the washers 51 and 58 acts to restore the valve member D to its neutral position, shown in Fig. 1, from the operating positions shown in Figs. 2 and 3 after the operating lever 68 has been released by the operator.

The body 45 of the operating valvev I6 is provided with an intake port and a plurality of ports 16, 11 and 18, through which the hydraulic fluid may pass from the valve I6. rihe body 45 of the selector valve I8 is provided with an intake port 86 and the aforementioned outlet ports 86 and 43 and a port 8|, which is not used and is closed by a plug 82. Each of the ports has an annular groove communicating with it and encircling and communicating with the central valve chamber 46 of its respective valve and is arranged in a predetermined relation to theienlarged piston heads 5I, 52 and 53 of the piston valve 50, as illustrated in the drawings.

'The outlet of the pump I4 is connected by a conduit 85'with the intake port 15 of the operating valve I6. A return conduit 86 connects the port 16 of the operating valve I6 with a reservoir 81 associated with the hydraulic pump I4 and a conduit 88 connects the port 118 with the return conduit 86. A pressure relief valve 89, set at a predetermined pressure, is connected between the inlet conduit 85 and the return conduit 86 to yby-pass hydraulic fluid therethrough when the pressure within the conduit 85 reaches the predetermined pressure at which the relief valve 89 is set.` When the valve member 58 of the operating valve I6 is in its neutral position, the uid from the pump I4 is adapted to pass through the conduit 85 and into the intake port 15 and to be by-passed through a passageway 98 in the piston valve member 68 and to return through the conduit 86 to the reservoir 81 associated with the pump I4. The passageway 98 comprises radial apertures 9| and 92 in the piston heads 5I and 52, respectively, aligned with port apertures 16 and 15, respectively, and connected longitudinally by a bore 93.

The outlet port 11 of the operating valve I6 is connected by a conduit 96 to the intake port 89 of the selector valve I8. The selector valve I8, as previously mentioned, is connected to each of the hydraulic actuators 28 and 22 through single conduits 29 and 42, respectively.

The piston valve member 58 of the operating valve I6 is adapted to be moved to its lower position, as indicated in Fig. 2, to establish communication between the intake port 15 and the outlet port 11 and to out olf the flow of hydraulic uid to the return port 16 andin which position the hydraulic fluid applied by the pump 44 passes through the valve I6 to the conduit 96. The operating handle 68 of valve I6 may be moved upwardly to raise the valve member 50 to the position shown in Fig. 3, which establishes communication between the outlet port 11 and the return port 16 and the intake port 15 and the return port 18, respectively. With the operating valve in this position, the fluid from port 11 may pass through the operating valve I6 and the return pipe 86 to the reservoir 81 and the hydraulic uid from the pump I4 circulates freely through the conduit `85, the operating valve I6 and the return conduits 88 and 86.

The operating handle 68 of the selector valve I8 may be moved upwardly or downwardly to move the piston valve member 58 upwardly or downwardly to establish communication between the intake port 89 and either the outlet port 38 or the outlet port 42, respectively, and admit uid into the lower end of the hydraulic actuator 28 or the hydraulic actuator 22, respectively. When the valve member 58 is moved to establish hydraulic communication between the intake port and one of the outlet ports, it also acts positively to block hydraulic communication with the other port so that when the selector valve is moved to select one hydraulic actuator to be actuated, it positively locksout the other. Thus the simultaneous operation of lthe mold supporting table Ill and the furnace I2 is prevented. With this mechanism, the possibility of injury to an operator and/or damage to the apparatus is minimized since it is impossible to simultaneously operate both actuators.

The operating handle 68 of the selector valve lil may be moved upwardly to raise the valve member 50 to its upper position, as shown in Fig. 2, to establish communication between the intake port 88 and outlet port 43. With the valve in this position, the conduit l96 is hydraulically connected to the conduit 42 and to the lower end of the actuator 22 for raising and lowering the casting furnace I2. By moving the operating handle 68 of the selector valve I8 downward to the position indicated in dot and dash lines in Fig. 2, the valve member 50 will be moved to its lower position and connect the inlet port 88 with the outlet port 30. With the valve mem- -ber in this position, the conduit 96 is in hydraulic communication with the conduit 29 and to the lower end of the actuator 28 for raising and lowering the mold supporting table Ill.

In the operation of the apparatus for casting molten material into bars, the molds 24 and the table I8, on which they are mounted, are moved to their lower position, as indicated in full lines in Fig. 1, where one of the molds 24 is in proper position relative to the casting furnace I2 to receive a charge therefrom. IThe casting furnace I2, after having been charged with metal and heated to bring the metal to a molten state, is tilted about the pivot 34 to pour the molten metal into the mold 24. To raise the casting furnace I2, the operator moves the operating lever 68 of the operating valve I 6 downwardly to establish a flow of hydraulic fluid from the pump to the conduit 96 and then the operator moves the operating handle 68 of the selector valve I8 upwardly to select the furnace actuator 22 and establish communication between the conduit 96 and the conduit 42 of the actuator 22. The hydraulic fluid under pressure from the pump i4 will then flow through the conduit through the operating valve I6, the conduit 96, the selector valve |18, the conduit 42 and into the cylinders 38 of actuator 22 and raise the pistons 36 connected to the casting furnace I2 and move the casting furnace I2 about the pivot 34. When the mold is full, the operator moves the handle 68 of the operating valve I6 upwardly past its neutral position to its upper position to move the piston valve member 58 therein to establish communication between the conduit 96 and the return conduit 86, the handle 68 of the selector valve I8 being maintained in its upward position. The fluid in the cylinders 38 of the actuator 22 is then free to move in a reverse direction, it being forced out by the downward movement of the piston 36 under the downward force of the casting furnace I2 and passes through the conduit 42 through the selector valve I8, the conduit 96,the operatagitata lne valve #1"'6 anu through the return tenerti es the handresfes of "the `"valves ift-'and -B, which areautomatically returned to *their neutral Ap`o ition. Thejtable I'G and,thehrolds24"thereon may ktlin be rotated to "align another 1nolc`l ""in receiving fpsit'ion with respect 'to 'the 'casting furnace Y`|`2 and "the cycle 'of f'operation Imay Y"be repeated to f11 the second ymeid. After au or 'me "moids't have been nued 4anu allow/edito cool, thetable "I0, lwith tlie molds '#24 thereon, is 'is'edolt'f "the pit l110 the level of "'tIIeAfiCorf, asfi'dicated in dotted lines in Fig. "l, where the molds 'may be opened and Vthe cast bars "or ints 'removed therefrom. In order-toiallow time fr the 'removal "of "the "ingtsfrin the molds, the table IIl is automatically hydraulicallyloclr'd in its upper .position by setting the handles 68 and valve 'ineinbers `5`13 in neutral position until the removal of the lingots from the mold is completed.

- ih'e operator, in order to raise the ram -21 and the table IU, moves the 'lever 68 of the operating valve I6 downward to connect the conduit 96 with the idpr'essure in conduit 85, after which the operator moves the handle 68 of the's'elector valve I8 downwardly to connect fthe fliidlp'ressure "in the 'conduit Sii lwith the 'conduit `2'9 Y'Corine'oted "to the :lower 'end of the actato'r '20. I'lui'd under `4pressure will then "pass Afi'rh the Drrip 'I4 "through 'the 'Conduitfa :the operatingvalve T6, the 'co'iid'uit "98., selectoryalve theselected actuator 21)"andfrai'se-the ram 21,'the table v4Ill "ahd the 'molds 24 'thereon upwardly. When the ram 21 and the table I8 have been raised to the proper height so that the table I is on the level with the floor 98, the operator releases the operating handles 68 of the valves IE and I8, which valves return to their normal neutral position and thereby prevent further movement of the ram 21 and table IIJ.

In its normal neutral position, the selector valve I8 cuts oi' the ilow of oil to the conduits 42 and 29, which serves to lock the actuators in the position then encountered and in this case serves to maintain the ram 21 and the table II] in its elevated position. The operating valve IG, with its valve member D in its normal neutral position, cuts off the flow of liquid through the conduit 9E and, being in series with the selector valve I8, acts as a double stop to block the flow of hydraulic fluid from either of the actuators or 22 through their respective conduits 29 and 42 and the selector valve I8'. Thus the ram 21, the table I0, with the molds 24 thereon, are maintained in their elevated positions, from which position they are prevented from settling by the effective means of the two valves I8 and I6 in series in the hydraulic system.

After the operation of removing the ingots from the molds has been completed and the molds are reassembled, the table ID, with the molds thereon, may be returned to their lower normal position. This is accomplished by the moving of the lever 68of the operating Valve I6 upwardly and moving the lever 68 of the selector valve I8 downwardly, which then establishes communication between the iluid in the actuator 2l) and the return conduit 8B to permit the fluid in the cylinder 28 under the downward force of the weight of the ram 21, table I0 and molds 24 to pass through the conduit 29, selece'it p inminente return fiotv'of'hyarane eine from einerofjtheacaiatrs zo ana'fzz when yvalve miiiber 'rof operating "valve 'I6 is lin-its upper position, as lindiatedfin Fig. f3, the hydraulic Tluidfroin the 'pump 7|74 passes through 'fthe valve 'f6 -and fthe eftiirnconduits "88 l"and 876 icon'riect'ed to "the 1feseifvoii f'a yand eircdiates lfree-1y without 'imposing-a lloadio'n 'the puin-p. .'n'd'er ordinary toneladas, it is @my when the hydraunc actu ai s areoprateuftciraise ertherthe more supporting table `nl or fthe lcasting ffur'nace izg'tnat 'the lpurr'xp vis v"operating "against ja *high working pressure, while "atfother times the pump isoperating unl'era minimum idlingpressure With "the valve member y"l'l of theoperating valve A'Hi init-he lowerposition; as shown 'in 2,"the`fh`ydra1ic`-luid from the `pump "Il willibe by-passed through the pressure relief valve li439 to the reser- 'virfm when the'selettor valve Is is in itsnutrai position 'or lwhen Ltire-"selectorvalve `r`I8 `is inl'i'the'r one of its operating positions-'andtherarnl'ffthe "actuator: connectedthereby is stopped-at its limit ofytravei. j

Whatis'claimed is:

l. l:An apparatus"forfcntrblling theoperatin of iflui'd operated actuators comprising "a selector valve having 'a closed normal position'and two 'open dif-normal positions, gan operating valve having a closed normal 'position and 't'wdopen 'off-normal positionsfrneans ineachof-saidwalves tending lto maintain itin normal position, `a pair of fluid operatedactu'ators-a single v"conduitic'on- 'necting one ofsaid 'actuatorsto 'oneof s'aidlpenoiT-normalpositions of said selector vvalve, a sin'- gle conduitconnecting tthe other of said actuators to the other open off-normal position of said selec-tor valve, said actuators being advanced by the flow of fluid therein in one direction and returned by gravity and the flow of iluid therein in the opposite direction, a single conduit con necting said operating valve to said selector valve, a pump, a, fluid reservoir `associated with said pump, a conduit connecting the pump to said operating valve for conducting uid thereto, and a conduit for returning fluid from said operating valve to said reservoir, said operating valve in one open off-normal position serving to direct the iiow of uid in one direction from said pump to said selector valve and in the other open off-normal position serving to by-pass the fluid from the pump to the reservoir and to direct the flow of fluid from the selector valve to the reservoir, and said selector valve in one open off-normal position serving to connect the operating valve rwith one of said actuators and in the other open off-normal position serving to connect the operating valve with the other actuator.

2. A hydraulic apparatus for operating a plurality of hydraulic actuators comprising a hydraulic pump, a reservoir for hydraulic fluid associated with said pump, a multi xposition operating valve, a conduit for conducting hydraulic fluid from said pump to said operating valve, a conduit for returning said hydraulic uid from said operating valve to said reservoir, valve means for by-passing hydraulic fluid from said pump to said reservoir when the pressure in said conduit from said pump exceeds a predetermined amount, a multi position selector valve, a hydraulic connection between said valves, a plurality of hydraulic actuators, means for conducting hydraulic fluid between said selector valve and each of said hydraulic actuators comprising a single conduit between each actuator and said selector valve, said actuators being movable from a normal position by the ow of hydraulic fluid therein in one direction under control of said valves and being movable to said normal position by gravity and the flow of hydraulic fluid in a reverse direction under control of said valves, said selector valve being operable to establish hydraulic communication between a selected one of said hydraulic actuators and said operating valve, said operating valve being operable in one of said positions to establish hydraulic communication between said pump and said selector valve `whereby uid under pressure may be delivered to said selector valve for distribution to one of said actuators, and said operating valve being operable in another position to by-pass the fluid from the pump to the reservoir and to establish hydraulic communication between said reservoir and said selector valve whereby fluid from said selector valve may be returned to said reservoir.

3. An apparatus for controlling the operation of a pair of Huid operated actuators comprising a hydraulic pump, a hydraulic uid reservoir assooiated with said pump, a multi-position operating valve having a closed normal position and two open off-normal positions, a conduit for conducting hydraulic Huid from the pump to the operating valve, a conduit for conducting fluid from the operating valve to the reservoir, a multiposition selector valve having a closed normal .position and two open off-normal positions,

single conduit for conducting fluid fromone to the other of said valves, a pair of hydraulic actuators, a single conduit connecting one of said actuators to one of said open olf-normal .positions of said selector Valve, a single conduit connecting the other of said actuators to the other open off-normal yposition of said selector valve, spring means for yieldingly retaining said selector valve in normal position, means for moving said selector valve toeither one of said open olf-normal positions to select either one of said actuators for actuation, spring means for yieldingly retaining said operating valve in said closed normal position, and means for moving said operating valve to either of said open off-normal positions, said operating valve in one of said open off-normal positions serving to direct the ow of fluid from the pump to the selector valve and ln the other open off-normal position serving to by-pass the uid from the pump back to the reservoir and to establish hydraulic communication rom th'e selector valve to the reservoir.

SVEN AAMOT.

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

UNITED STATES PATENTS Number Name Date 1,147,820 Scott July 27, 1915 1,711,565 Hatfield May 7, 1929 1,759,647 Kincannon May 20. 1930 1,904,112 Achard Apr. 18, 1933 1,940,043 Bordeaux Dec. 19, 1933 2,100,445 Le B1eu Nov. 30, 1937 2,160,596 Le Bleu May 30, 1939 2,203,939 Barrett June 11, 1940

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