US2273649A - Hydraulic control system - Google Patents

Description

Fel.v 17, 1942.

H. F. LAWRENCE HYDRAULlGA CONTROL SYSTEM originalA Filed March 24, 1937 nh x E E vll E D m n TL mm1 n m m m um .v

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I "ctente'd'y Feb. 1942 l IUNITED STATES vorifice HYDRAULIC coNraor. SYSTEM Howard F. Lawrence, Philadelphia, Pa., assigner to American E ngineering Company, Philadei.

f phia, Pa., a corporation of Pennsylvania Original application March 24, 1937, Serial No:

132,689, now Patent No. 2,221,313, dated November 12, 1940.

Divided and this application May 29, 1940, Serial No. 337,803

` (ci. ca -52) 8 Claims.

This application is a division of mypending application Ser. No. 132,689, filed March 24, 193'1, on which Patent No. 2,221,313 was granted on November 12, 1940, for Hydraulic control systems, and the invention herein described relates to hydraulic control systems, and more particularly to systems employedto reverse the direction of discharge of pumps whenthepressure thereby exceeds a predetermined developed value.

One object of the present invention is to provide a generally improved -and simplified control system of the stated character which is fully automatic in operation.

Another object is to provide a system of the stated character wherein thepump controls are positively actuated to effect a reversal ofthe discharge therepf. l

A further and more specific object is to provide in a iluid system including a high pressure Ipump for actuating feeding rams, a control de- Referring to the drawing, thehydraulic cone taken substantially trol system comprising'the present invention includes a pump |40 which,'in the present in\ stance, is adapted to operate a pair of fluid motors |56. The operation of said fluid motors .is controlled by a valve |4|, which in'turnls 'actuated by a control system hereinafter fully de- Pump Mu in by an electric motor A|42 through any suitable coupling |43, vFluid is supplied to the system from a makeup or supply tank |44` which is connected toone side'of the pump -by an intake pipe |45.

Pump v|40 may be vof the general type 'shown in Patent No.l 1,077,979, or any vother suit'- able type and, as shown in Fig. 1, discharges fluid under pressure into a pipe |46, which pipe is connected to a port' |41" communicating with the k central cylindrical chamber |40 of valve `|41. Valve |'4| has provided therein a pair of spaced the present instance is operated ports |49 and |50, which ports are connected vrespectively to one end of Vpipes and y|52. Pipes |5| and |52 are connected by branch pipes v|56 and |54, to the opposite ends of the cylinders 5- |55 of fluid motors |56. Cylinders |55 have pistons |51 operating therein to which feeding rams may be connected in any suitable manner. Valve |14| has also provided therein a port |56- at one end thereof which is connected to makeup tank |44 by means of a pipe |59., The reduced v portions |60 and |6| at the Opposite ends of chamber |48 'are connected by means of'a pipe |62. Valve |4| has provided therein a valve element' |63 having a p-ir of valve heads |64 and |65 connected'by reduced portion |66. Valve element |63 has a 'stein |61 secured nthereto which extends through the end wall |66 of valve 4|. The opposite end of valve stem |61 has secured thereto a piston |69 which operates in the cylinder |10 of a iuid motor |1| secured in any suitable manner, such as by bolts |12, to the casing of,valve |4|. The-head end |13 of motor |1|v is connected to a normally closedI port |14 of va,r

, control valve |15 by means of'apipe |16. The other end of motor |1| is connected to a secondof the invention proport `,|11 of control valve |15 by means of a'second v-pipe |16. Control valve |15 has provided therein a. pair of cylindrical chambers |19 and y|60 which are connected at-one end there`of by a passage |6| and ports`|62 and |66. Chamber |19 has provided therein a vvalve element |64, consisting of a pair of valve heads '|65 and |66 connected by a reduced portion |61, 'I'he upper end of valve element |64 has secured thereto a reduced Vguiding extension |66 which extends through a guiding aperture .|69 provided at the provided ltherein an adiustablerelief 'valve which in' turn is connected to makeup tank |44j upper end of control valve |15. Chamber |66 also'haspiovided therein a similarly constructed valve-element |90 consisting of a pair of valve heads |9| andv |92 connected by a reduced. portion |93. One end of valve |90. also has secured thereto a reduced guiding extension |94 which extends through a'second guidingv aperture |95 in line with chamber |601 The upper end of chamy ber |19 is connected to-pi e |52 by means of apipe |96. The upper end of chamber is connected to pipe 5| 'by a pipe |91. Passage |6| is connected to a small pump-|96 by means of a pipe |99. Pump |98 is connected to theshaft 206 of pump |40 by a chain and sprocket mechanism 20|. Fluid is. drawn into pump |96 frommakeup tank |44through a pipe 202. -Pipe |99 las` byvmeanls of a pipe 204.l Relief valve 203 may be 'of any suitable construction which will open to exhaust when the pressure imposed thereon exceeds a predetermined value, as fully set forth in my above noted Patent No. 2,221,313.

The cylindrical chambers |19 and |80 of control valve |15 are interconnected intermediate the ends thereof by means of a transverselpassage 205. A second passage 206, extending substantially at right-angles to passage 205, extends from the latter to the outside of the casing of valve |15, and a. pipe 201 connects passage 206 with makeup tank |44. Any iiuid leaking past tons |51 reach the limit of their travel in this direction, the pressure developed by pump |40 the upper guide portions |88 and |94 of valve members |84 and |90 respectively, flows into a vertical passage 208 which extends fromthe upper end of valve |15 to passage 206. It will be observed that when valve members |84 and |90 are in their uppermost position, the ports |11 and |14 are only partially covered by the valve heads |85 and |9| respectively. `Thus, when valve |90 is in the positionwshown in Fig. 1, and iiuid from pipe |5| flows through pipe |91, port |14 and pipe |16 to the head end of piston |69;"the iiuid at the other end of cylinder will pass through pipe |18, port |11, the annular cham-- ber between valve heads |85 and |86, transverse causing pump |98 to move valve element |84 up- `hand ends of cylinders |55, causing the pistons |51 operating therein to move to the'left. The fluid at the left hand end of cylindersv 55 now iiows to makeup tank as previously described, through pipes |54, |52; port |50, chamber |48, and pipe |59. As soon as valve |63 is 'shifted to the position shown in Fig. 1, the pressure of the fluid at the upper end of chamber |19 is relieved,

wardly. Fluid at the upper end of chamber |19 will now iiow to makeup tank through pipe |06,

fpipe |52, chamber |48 oi valve |41, andpipe |59.

passage 205, passage 206, and pipe 201, to makeup tank |44. On the other hand, when'valve |90 is in its upper position, and valve |84 is in its lower position, iiuid from the head end of cylinder |10 will flow to makeup tank |44 through pipe |16, gport |14, the chamber between valve heads |9| and.|92, transverse passage 205, pas'- sage 206, and pipe 201.

From the foregoing description it is seen' that port |41 of valve |4| at all times is disposed between valve heads Y |64 and parts are in the position shown in Fig.l 1 fluid from pump |40 enters the central chamber |48 of valve |41 through pipe |46 and port |41. Fluid then flows to the right hand ends 'of cylinders |55 through pipe |5|, causing pistons |51 to move to the left. #Fluid at the left hand end of cylinders |55 then iiows to makeup tank through pipes |54, |52, port |50, chamber |48,H

the reduced portion |6| thereof, and pipe |59.

en `pistons |51 reach the limit of their travel in this direction, pressure builds up in pump |40. This pressure is transmitted to the upper end of valve member |90 through pipe |91. When this pressure is suiiicient to overcome that imposed against the lower end of said valve member by the small pump |98, valve element |90 moves downwardly, thereby uncovering port |14 to pel"- mit iiuid under pressure to enter the head end of motor |10. Piston |69 of mutor |1| 'now actuates valve element |66 to its other extreme |85. When the4 This procedure is repeated to eiect reverse operations of pistons |51 when they reach their limit,l

of travel in either direction.

It therefore is seen that a simplified, as well as highly improved hydraulic control system'has been provided which positively reverses the discharge of the pump when the pressure in the f system exceeds a predetermined value.

While the embodiment herein shown and described is admirably adapted to fulfill the objects primarily stated, it is to be understood that the invention is not to be limited thereto, since it may be embodied vin other forms, all coming within the "scope of the' claims which follow.

What is claimed is:

1. In a device of the class described, the combination of a pump, a pair of pipes for alternately .e delivering fluid pressure from said pump, a disposition of adjustment, and thereby establishes communication between pump 40 and pipe |52.

Fluid now enters the left hand end of cylinders |55, thereby causing the pistons 51 operating therein to move to the right. The uid at the vright hand end of cylinders |55 will now ow back to makeup tank through pipes |59, 5 port |49, chamber |48, reduced portion |60, pipe |62, reduced portion |6|, andepipe |59.4 As soon as Dvalve |63 moves downwardly to connect ports |41'andl50, thereby causing the discharge of pump 40 to enter pipe |52, the pressure at the upper end of valve head |9| isrelieved, and consequently valve |90 -is moved upwardly by the pressure from pump |98. The huid at the upper end of chamber |80 now passes to makeup tank through pipes |91 and |5|, port. |49., chamber |48, pipe |82, port |58 andpipe |59. `When pistributing valve for controlling the ow of iiuid in said pipes, normally inoperative fluid pressure means for adjusting said valve to different positions of adjustment, valve means for controlling the operation of said iiuid pressure means, means bination of a ,pump, a pair of pipes for alternately delivering fluid pressure from said pump,

a distributing valve for controlling the ow of fluid in said pipes, normally inoperative iiuid pressure means for adjusting'said valve, a valve mechanism consisting of a pairof valve velements for controlling the operation of .said fluid preselements with one of said pipes, means'connecting one end of the other of said elements with the pther ofy said pipes, an auxiliary source of fluid pressure, means connecting the other -end of each of said valve elements to said auxiliary source of pressure, whereby when the pressure in either of said pipes imposed upon said valve ele-Y ments exceeds that imposed upon said valve elements by said auxiliary source of fluid pressure` the valve element subjected to such pressure ymoves to open the associated discharge port to a distributing valve for controlling the flow of fluid in said pipes, normally inoperative servo motor means operated bythe uid pressure developed in said pump for actuating said distributing valve to different positions of adjustment,

a valve mechanism comprising a pair of valveelements for controlling the operation of said servo motor means, means connecting one end of one of said valve elements to one of said pipes, means connecting one end of the other of said valve elements to the other of said pipes, an auxiliary pump, and means connecting the opposite end of each of said valve elements to said auxiliary pump, whereby when the pressure developed by said first mentioned pump exceeds that developed by said auxiliary pump, the valve element subjected to such pressure operates to render said servo motor operative toeffect adjustment of said distributing valve.

4. In a device of the class described, the combination of a pump, a pair of pipes for alternately delivering fluid pressure from said pump, a distributing valve for controlling the flow of fluid in said pipes, normally inoperative servo motor means operated by the fluid pressure developed in said pump for actuating said distributing valve to different positions of adjustment, a valve meclanism comprising a pair of valve elements for controlling the operation of said servo motor means, means connecting one end of one of said valve elements to one of said pipes, means connecting one end of the other of said valve elements to the other of said pipes, an auxiliary pump, means connecting the opposite end of each of said valve elements to said auxiliary pump, whereby when the pressure developed by said first mentioned pump exceeds that developedrby said auxiliary pump, the valve element subjected to such pressure operates to render said servo motor operative to effect adjustment of said distributing valve, and means for varying the pressure developed by said auxiliary Pump.

5. In a device of the class described, the combination of a main pump, a double-acting fluid motor operated by the said main pump,'means controlling the ilow of iiuid from said pump to said uid motor, normally inoperative servo motor means for actuating said VAcontrolling means,

the other end of said valve means tothe pressure side of said auxiliary pump whereby when the pressure imposed upon said valve means by said main pumpexceeds that imposed thereon by said auxiliary pump. said valve means operates to yrender said servo means operative to effect adjustment of said controlling means. 6. In a device of the class described, the combination of a main pump, a fluid motor operated by said main pump, a distributing valve for controlling the flow of iiuid from said pump to said uid motor, normally inoperative means for adjusting said distributing valve, valve means for controlling the operation of said normally inoperative means, means connecting one end of said valve means to the pressure side of said main pump, an auxiliary pump, and means connecting the other end of said valve means to the pressure side of said auxiliary pump whereby when the pressure imposed upon said valve means by saidmain pump exceeds that imposed thereon by said auxiliary pump said valve means operates to render said normally inoperative means operative to eiect adjustment of said distributing valve.

7. In a device of the class described, thecombination of a main pump, a fluid motor operated by saidmain pump, a distributing valve for controlling' the i'low of fluid from said pump to said fluid motor, normally inoperative means for adjusting said distributing valve, valve means for controlling the operation of s aid normally inoperative means, means connecting one end of saidvalve means to the pressure side of said main pump, an auxiliary pump, means connecting the other end of said valve means to the pressure side of said auxiliary pump whereby when the pressure imposed upon said valve means by said main pump exceeds that imposed thereon by said auxiliary pump, said valve means operates to render said normally inoperative mally inoperative means, saidvalve mechanism comprising a pair of valve elements, means for alternately connecting one end of each of said valve elements to the pressure side of said main pump, an auxiliary pump, and means connecting the opposite end of each of said valve elements to the pressure side of said auxiliary pump whereby when the pressure imposed upon either valve means for controlling the operation of said servo motor, means connecting one End of said valve means to the pressure sideof saidv main pump, an auxiliary pump, and means connecting of 'said valve elements by said main pump exceeds that imposed thereon by said auxiliary pump the said valve element subjected to such

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