US2304380A

US2304380A - Hydraulic valve

Info

Publication number: US2304380A
Application number: US406027A
Authority: US
Inventors: George D Shaeffer
Original assignee: Gar Wood Industries Inc
Current assignee: Gar Wood Industries Inc
Priority date: 1941-08-08
Filing date: 1941-08-08
Publication date: 1942-12-08
Anticipated expiration: 1959-12-08

Description

G. D. `sHAEFFER HYDRAULIC VALVE Filed Aug e, 194i 3 Sheets-Sheet l IN VEN TOR B Y A TTORNE YS.

Dec. 8, 1942. G. n. sHAEr-r-ER HYDRAULI C VALVE 3l Sheets-Sheet v2 Filed Aug.` 8, 1941 INI/ENTOR fea/*ge JSZVQe/yef: BY

4 A T7 'ORNE YS.

De@ 8, 1942- G. n. sHAEr-FER 2,304,380

HYDRAULIC VALVE Filed Aug. s, 1941 :s sheets-shears jf 4 f3?- ATTORNEYS.

Patented Dec. 8, 1,942

HYDRAULIC VALVE George D.

GarA Wood Industries, corporation of Michigan Application August 8, 1941, Serial No. 406,02'1

(Cl. 12h- 40) 'l Claims. The present invention relates to improvements V in hydraulic valves and particularly to such valves when used to control the operation of hydraulic elements on road working machines, such as bulldozers and scrapers.

One of the primary objects of the present invention is to provide improvementsvin valves of the type mentioned in which the possibility of an hydraulic lock in the system is eliminated.

Ihe further` object of the present invention is to provide improvements in valves of the type mentioned, including a check and poppet valve in certain oi the conduits, in which such check and poppet valve is positively unseated so that there is no possibility'of an hydraulic lock in the system.

Other objects of the invention will become apparent from the following speciication, the

drawings related thereto, and from the claims hereinafter set forth.

Referring to the drawings in which like numerals are used to indicate like parts in the several views throughout: l

Figure 1 is a perspective, cross-sectional view I of an hydraulic valve with parts in elevation embodying features of the present invention;

Fig. 2 is a cross-sectional view taken substantially along the line 2-2 of Fig. 1;

Fig. 3 is a diagrammatic view illustrating an -hydrauliccircuit employing the valve of the pres.

ent invention and illustrating in such circuit a work element in the form of an hydraulic jack; and

Figs. 4, 5,and 6 are diagrammatic, cross-sectional views of the valve of the present invention` andshowing the elements of such valves in different operative positions, the circular inlet and outlet ports being shown out of their true posi tions for purposes of clarity.

In certain respects, the present invention relates to the type of valve disclosed in the copending application of Louis F. Buran and George D. Shaeifer, Serial No. 354,020, iiled August 24, 1940, now Patent No. 2,274,527, issued February 24, 1942.

The valve of the present invention has particular utility when used in association with hydraulic jacks which serve to operate certain elements of road working machines such as scrapers and bulldozers. One of the serious problems in the operar tion oil such machines has been the elimination of the possibility of hydraulic locks in the iluid systems. For example. in bulldozers, hydraulic jacks are utilized to power up and powerdown the scraper frame and blade. It will be appreciated that, when the frame and blade, are powered up, there is considerableforce exerted on the jack piston and fluid in the cylinder due to the suspended Weight of the frame and blade. The result o this is the transmission of a considerable Inc., Detroit, Mich., a

back pressure in the hydraulic system, and such back pressure may introduce an hydraulic lock in the system which will prevent proper operation of the device.

Referring first to Fig. 3, the system includes, in general. a valve generally indicated at Il having an inlet pipe I2 and an outlet pipe i4 connected to an inlet and outlet formed respectively in the valve housing. The inlet=conduit..i2 connects with the outlet of a conventional pump i6, such pump I6 having an inlet pipe il which is adapted to be immersed within the iluid 2l, such as oil, contained within a tank 22. The usual means, not shown, for driving the pump is provided.

The valve I0 also has an operating handle 24 attached to a distributing valve plunger for shifting the plunger therein and for controlling the iiow of fluid through the valve.

Pipes or conduits 26 and 2l connect with ports formed in the valve. il and are connected to ilexible conduits 36 and I2, respectively. Such conduits 3l and 62 serve to conduct fluid under pressure to and exhaust the iluid from an hydraulic jack generally indicated at 34. Such jack I4 includes the usual cylinder 36 and piston 16 having a piston rod 40 which extends through the cap end thereof. The jack is oi! the double acting type with the conduit I0 communicating with one end thereof and withthe conduit 32 communicating with the cylinder 36 on the opposite side of the piston 3l so that the piston may be powered in either direction. It-will be understood that the piston rod 40 is connected to a work element such as the scraper frame of a bulldozer.

Referring to Figs. 1, 2, 4, 5, and 6, the construction of the valve III of the present invention is illustrated in detail. Valve l0 comprises a cast metal casing 42 which is formed with a pair of parallel bores 44 and 46 therein. The bore 44 has a pluralityof longitudinally spaced

annular chambers

48, 50, 52, 54, 56, and 58 communicating therewith. An inlet port 80 is formed through one of the side walls of the casing 42, and an outlet port 62 is formed in the opposite side of the casing and oppositely disposed to the port 60. A pair of branch passageways 64 communicate the inlet port with the annular chambers 50 and 56. A pair of branch passageways 66 communicate the outlet port 52 with the annular chambers 52 and 54.

A passageway 68 communicates the annular chamber 48 with the bore 46, and a passageway l0 communicates the annular passageway 5l with the bore 46, so that the bores 44 and 46 are communicable with each other.

A slidable valvev plunger 12 having enlarged

cylindrical portions

14, 16, and 16 is slidably disposed within the' bore 44 with the ends of the plunger 12 projecting through the open ends oi the casing 42 i bore 44. The

- sageway 68 which leads to the bore by the cylindrical portion such bore 44. A link 80 is pivotally connected to one of the projecting ends of the plunger 12 and is operatively connected to the operating handle 24 for sliding the plunger l2 longitudinally of the bore 44. An enlarged annular recess 82 is formed in the housing 42 concentric with the bore 44 and adjacent the link .00. Another annular recess 84 is formed in the opposite side of the housing 42, concentric with the bore 44 'and through which the opposite end of the plunger 12 projects. 4

A cage 86 having longitudinal openings 88 formed therein, is suitably xed to the side of in concentric relationship to the reduced end 90 of the plunger 'i2 extends through the case 86 longitudinally thereextending fingers 94 formed integrally therewith. Such ngers 94 extend outwardly to a position adjacent the inner wall of the cage member 06 and are adapted to engage the inturned shoulders 90 on the ends of the cage when such member 92 is in its outermost position. A nut 98 is threaded onto the end of the reduced portion 90 and is adapted toA abut against the hub 92.

Another hub member 99 embraces the reduced portion 90 adjacent the bore opening through the casing wall and is formed with a plurality of integral, longitudinally extending legs which are formed vwith outturned feet |02. Such feet |02 are adapted to be` received within the recess B4 and abut against the radial wall thereof.`

A helical spring. |06 is disposed within the case 8s in surrounding relationship to the reduced end ofthe plunger l2 4and is positioned with one end of the spring abutting against the members 94 and the opposite end of the spring abutting against the feet |02 of members mi.

The hub member 99 abuts against a shoulder |06 lformed on the plunger '|2 adjacent thereduced portion 90 so that the spring |04 acts against. the members 92 and 99 to center the plunger in its normal center position as shown in Fig. l. The abutment of the hub members 92 and 99 against `each `other 'upon movement of thelplunger in either direction serves to limit such movement of the plunger 12 in' either direction.

The cylindrical portions '|4, 16,and 18 are of such lengths vwith respect to the distances between their

corresponding 4chambers

48, 50, 52, 54, 56, and 58 that when the plunger 'l2 is in its central or neutral position, as shown in Figs. l and 5, the oil under pressure which is introduced through the conduit I2 enters through the inlet port 60 and passes through passageways 64 into 4 the annular passageways 50 land 56 and thence into the bore 44. Such uid passes then towardl the central part of the bore into annular passageways 52 and 54 and thence outwardly through outlet port 62 through branch passageways 66.

When the plunger 12 is shifted to the left, as shown in Fig. 4, the cylindrical portion 14 is so positioned as to block oii ow of iluid through the Aopening of the bore 44. Ihe fluid from the inlet 00 then passes through one of the branch passages 64 into the bore 44 and outwardly through the annular chamber 48 into the pas- 46. The oppassageway 64 -is then blocked o T8. The passageway then communicates with the interior of the posite branch is then discharged outwardly through the annular opening 82 where it may drop back into the tank. With this setting of the plunger, the

cylindrical portions

16 and 18 block oif the ow of iluid to the outlet port 62. I

With' the pistons 12 shifted in the opposite direction, that is to the right, as shown in Fig. 6, the high pressure fluid passes into the passageway 10 and from there into the bore 46; and the fluid is exhausted from the bore 46 through the passageway 68. The fluid leaving from passageway 68 passes through the open end of the bore 44 -which is surrounded by the case 86 and the leg members |0l. Such fluid is free to pass between the legs |0| and to pass through the openings 08 in the cage and fall back into the tank.

From the description of the operation of the structure of the present invention so far described, it will thus be seen that the uid under pressure may be introduced into either of the passageways 68 or l0 and may be exhausted from either one of such passageways. Also, the `iiuid may pass directly from the inlet 60 to the outlet port 62 with the plunger set as shown iny Figs. 1 and 5.

In order to control the flow of fluid to and from the hydraulic jack 34, novel means are provided within the bore 46.' The casing 42 is provided with an outlet passageway |00 which communicates with the bore 46 and which is positioned to the left of the passageway S0, as viewed in Fig. l. Another annular passageway H0 is formed in the casing between passageways G8 and 70 and communicates with the bore 40. The

passageways |00 and H0 communicate with ports H2 and H4,

respectively;y and such ports i2 and H4 are connected with the conduits 20 and 29,'

46 through an annular passageway which forms a shoulder which abutsagainst one end of themember therebetween.- 'I'he cap |26 has a reduced portion |30 which is telescopically received within 'l the end of member |22 and which forms a shoulder against which the end of member |22v abuts, witha seal interposed therebetween.

'Ihe member |20 is formed with an inset, an-

nular portion |32 which is telescopically receivedy of circumferentially spaced openings |36 therearound and with a plurality of another set of spaced openings |38 therearound, both sets the annular chamber |08.. The member |22v is provided-with a set of circumferentially spaced bore 44 through the annular passageway 58 and 75 communicate with the annular chamber Ilo and |20, `with a seal interposed of which communicate withl the cap |26 with its opposite end embracing the l projection |64 so that the valve plunger |40 is resiliently urged to the left, viewing Fig, 1.

A cup-shaped, check and poppet valve |60 is slidably received within themember |20 with the 4-annuiar valve seat |04.

`so that auch right as shown in Fig. 4.

face of such element extending toward the valve plunger |40. Such face is formed with a` taper |02 which is adapted to seat against the l A helical spring |04 is so disposed that` one end thereof is received within the recess o! projection |20, and the opposite end thereof is received within the recess of the cup-shaped member |00 valve element |00 'is urged toward the right, viewing Fig. l. The spring |04 thus acts to seat the tapered portion |62 on the valve seat |04 and therefore stronger than the spring |00.

Referring to Fig. 4, when the plunger 12 is so tion. the following action takes place which will prevent any hydraulic lock in the system due to the above mentioned back pressure. It will be appreciated that in order to prevent such hydraulic locking, the valve element |60 must be vunseated so that the iluid on the underside of the piston 06 may be exhausted through the openings |06 and pass into the passageway 60 which is then serving as-an exhaust passageway.

This is accomplished in that the end |02 of the valve plunger |46 is engageable with the face of the member |60 and when the iluid under pressure enters through openings |44, such iiuld cannot pass into the passageway |`|0, due to the position of the cylindrical portion |50, until such. lvalve plunger has moved a predetermined distance to the left. In moving such distance, the projection |62 strikes against the member |60 and the high pressure from the passageway 10- acting upon the valve piston |46 will thereby cause the valve element |00 to be unseated and positively move such element |00 to the left providing exhaust communication between the openings |00 and the interior of the projection |02.

The tiuid within the chamber |00. including that behind the element |00, may then be exhausted through the passageway |40 into the passageway 00 from which it may pass through the open set that the fluid under pressure enters into passageway 00, such iiuid ings |40 and unseats the valve element |00 so that such huid may then pass through openings |00 into the annular passageway V|00 and out through port ||2 into the conduit 20. Thus, the plunger 00 is moved upwardly. With such' plunger operatively connected with a work element such as the frame and blade oi` a bulldozer so that movementin that direction raises the bulldozer. it will then be lseen that when the plunger 12 is returned to its neutral position,

the weight of the frame and blade will exert a back pressure in conduit 20 which will be exerted on the inside of the valve element |00 through openings |00. This is the "hold" position and the blade and frame will be held in such elevated position until the plunger 12 is shifted again.

With the plunger 12 set in the position shown in Fig. 4, it will be seen that the fluid on the opposite side of the plunger 06 will be exhausted through conduits 00, 26 through port ||4, into annular passageway ||0, through openings |42 and |44 into annular passageway ||0 and thence into passageway 10 from which it is discharged through the opening 62. The pressure of the passes through the open` u iiuid from passageway 60 within the member |22 will'have shifted the valve plunger |46 to the under pressure enters through conduit 10 in order to .power the piston 00 in the opposite direcend of the bore 44, as shown in Fig. 6.

The valve plunger |40 may then continue in its movement to the lett to the full position shown in Fig. 6 so that the iluid under pressure may enter the annular passageway 0 through' the o s |44 and |42. From the passageway ||0, .the iluid under pressurepasses through port ||4' and into the upper end of the cylinder 06 through the conduits 20 and 00.

It is pointed out that the relative longitudinal distances between the openings |42 and |44 and between the valve seat |04 and openings |06 is such that the fluid under pressure from the passageway 10 cannot pass through openings |42 into the passageway ||0 until the element |60 has been moved to open the openings |00 for the exhaust of uid therethrough.

In describing another operation of the valve, when the device is powered down as shown in Fig. 6, and when after such powering down thevalve is returned to its hold position, as shown in Fig. 5, there may be a back pressure in the conduit ||4. Such back pressure is thel result of powering down tosuch an extent that the forward end of the tractor is raised oiI the ground. With the valve of the present invention an hydraulic lockcannot result.

From the drawings it will be seen that after such a hold position, if it ls desired to power up, as illustrated in Fig. 4, the fluid under pressure enters the bore 46 through passageway 66. Such passageway communicates with lthe interior of the bore between the valve piston portion |46 and the valve element |60 so that its pressure is effective on the faces of the valve |48 and that portion of the face of valve element |60 which is within the reduced annular portion of the oiiset |32. The eil'ective area of the valve |62 is of less area than the eiiectivev area on valve portion |46. Since the valve |46 is balanced when in the hold position due to the pressure from passageway liu acting upon the inside faces of portions |46 and |50, itwill be seen that the pressure from passageway 66 acting on the outside face of valve portion |48 will cause it to move from the position shown in Fig. A5 to the position shown in Fig. 4 to thereby communicate the` portA with .the passageway '10. This movement of the valve H2 will take place before the valve |80 is unseated. There, therefore, cannot be any hydraulic lock.

Fromthe above it will beseen that there can be no hydraulic locking of the valve of the present invention in moving from the hold position to either position of the valve.

What is claimed is:

` 1. In a hydraulic system, a cylinder and piston of the other positions, or in any otherwork means, hydraulic valve means for distributing iiuid under pressure through first and second conduits to said cylinder on opposite sides of said piston, said valve means including avcasing having a chamber therein, valve means for controlling the inlet and exhaust of fluid from said chamber through first and second passageways,

said first and second passageways being arrangedl for the passage of fluid i'nto and out ofsaid chamber at spacedjpoints therealong, first and second ports communicating with said chamber and communicating with'said first and second conduits, respectively, a valve said chamber and operable vto to and from said first valve element slidably disposed within saidchamber and operable to controlthetfiow of 4fiuid to and from said second passageway and tojand from said second uting fluid under pressure through iirst and second conduits to said cylinder on opposite sides of said piston, said valve means including a casing liaving a chamber therein, valve means for controlling the inlet and exhaust of fiuld from said chamber through first and' second passageways, said first and second .passageways being arranged for the passage of iiuid into and out of said chamber at spaced points therealong, first and second ports communicating with said chamber and communicating with said first and second conduits, respectively, a valve piston slidably disposed within said chamber and operable to control the fiow of fluid to and from said first passageway and to and from said first port, a valveelement slidably disposed within said chamber and operable to control the iiow of fiuid to and Ifrom said second passageway and to and from said second port, said valve piston and said valve element being separable and engageable and ybeing movable toward and away from each other, said second passagewaycommunicating with said chamber between said valve piston and said valve element so that fluid under pressure from said second passageway is effective on -bothsaid valve element and said valve piston, said of iiuid to andirom said firstf can-fiow lfrom sure can flow first passageway communicating with said chamber in such a position that duid under pressure therefrom is eliective on said valve piston, said valve piston and said valve element being so disposed with respect spect to ing having a chamber therein, valve means for controlling the inlet and exhaust of fluid fromsecond conduits, respectively, a4 valve piston slidv ably disposed within said chamber and operable and fromsaid first passageway andto and` Ifrom said first port,

a check. valve element slidably disposed ,within said chamber and operable to control the flow of said second passageway and to and from said second port,said valve pistonA to control the iiow. of iiuid4 tol fluid to and from and said valve element being separable and .en-

gageable and being movable toward and awaysaid second passageway com,-

municating with said chamber between said valve I piston and said valve element so that fiuid under said with respect tov first port.

4. In a hydraulic system, a cylinder and piston work means, hydraulic valve means for distributsaid chamber through first and second passageways, said rst on opposite sides of said piston, said valve means including a casand `rnovabletcward and duid under pressure .chamber through said second passageway said v ing having a chamber e respect to each other and with away from each other, said second geway communicating with said chamber between said valve piston and said valve element so that duid under pressure from said second passageway is edective on both said valve element and said valve piston, said drst passageway communicating with said chamber in such a position that duid under pressure therefrom is edective on said valve piston, said valve piston being movable away from said valve element at a lower unit duid pressure than said valve element, said valve piston and said valve element being so disposed with respect to each other and with respect to said ports that when is introduced into said valve piston is moved to permit dow of duid from said drst port to said drst passageway-before said valve element is unseated to permit dow of duid to'said second port. i v

5. In a hydraulic system, a cylinder and piston work means, hydraulic valve means for distributing duid under pressure through drst and second .conduits to said cylinder on opposite sides o! said piston, said valve means including a castherein, valve meansfor controlling the inlet and exhaust of duid from said chamber through drst and second passageways, said drst and second eways being arranged for the passage o! iiuid into and out o! said chamber at spaced points therealong, drst and second ports communicating with said chamber and communicating with said drst and second conduits, respectively,.a valve piston slidably disposed within said chamber and operable to 'control the dow oi' duid eway and toand from said drst port, a valve element slidably disposed within said chamber and operable to control the dow of duid to and from said second eway and to and from said second port. said valve piston and said valve element'being separable and engageable` and being movable toward and away from each other, said second with said chamber between said valve piston and said valve element so that duid under pressure from said second passageway is edective on both said valve element and .said valve piston, said drst passageway communicating with said chamber in suclra position that duid under pressure therefrom'is edective on said valve piston, said valve element being o! less edective area when seated than said valve piston, said valve piston and said valve element being so disposed with respect to said ports that when duid under pressure is introduced into said chamber throughsaid second eway said valve piston "dow of Aduid from said drst pori'rto said'drst way before said valve element is unseated to permit dow of duid to said second port.

6In a hydraulic system, a cylinder and piston work means, hydraulic valve means for distributing duid under pressure through drst and second conduits to said cylinder on opposite sides of said piston, said valve means including a casing having a chamber therein. valve means for controlling the inlet and exhaust of duid from said chamber through drst and second www said drst' and second peways'being arranged ior the e or duid into and out o! said chamber at spaced points therealong, drst and second ports communicating with said chamber eating lwith passageway communicating is moved to permit v 2,304,3so

- posed within said chamber and operable control the dow of duid to and from said drst .passageway and to and from said drst port, a valve element slidably disposed within said chamber and operable to control the dow of duid to and from said second passageway and to and -irom said second port, said valve piston and saidvalve element being separable and engageable and being movable toward and away from leach o said second passageway communicating with said l chamber between said valve piston and said valve element so that duid under pressure from said second' passageway is eiective on both said valve element and said valve piston, said drst passage- 'way communicating with said chamber in such a position that duid is edective on said under pressure therefrom valve piston, unbalanced springs urging said valve piston and said valve .3 toandfromsaiddrst' 5 controlling the inlet and exhaust -ond conduits, respectively,

first -eway element toward each other, said valve piston and said valve element being so disposed with respect to each other and with respect to said ports and said springs being unbalanced so element is unseated to permit dow of duid to said second port.

7. In a hydraulic system, a cylinder and piston workmeans, hydraulic valve means for distributing duid under pressure through drst and second conduits to said cylinder on opposite sides of vsaid piston, said valve means including a casing having a chamber therein, valve means for of fluid from said chamber through drst and second passageways, vsaid drst and second eways being arranged for the passage of duid in and out of said chamber at spaced points and second ports ber and communicating with said drst and seca valve'piston slidably within said chamber and operable to control the dow of duid to and from said drst passageway and to and from said drst port, a valve element slidably disposed within said chamber and operable to control the dow of duid to and from said second passageway and to and from said second port, said valve piston and said therealong, drst valve element being separable and engageable and beingmovable toward and away from each other, said second passageway communicating with said chamber between saidl valve piston and said valve element so that duid under pressure from said second passageway is edective on both said valve element and said valve piston, said communicating with said chamber in such a position that duid under pressure therefrom is edective on said valve piston, said under pressure can way to said drst port and that when duid under to permit dow of duid seated toifpermit valve piston being movable away from said valveY element at a lower unit duid pressure than said valve element. said valve piston and said valve element being so with respect to each other and with respect to said ports that when duid imder pressure is introduced into said chamber through saidv drst eway said valve piston unseats said valve element before duid dow from said drst passagepressure is 'introduced into said chamber through said second passageway said valve piston is moved from said drst port to said before said valve element is' undow of duid to said second pori;t

GEORGE D.

drst passageway that when duid under pressure is introduced into said chamber communicating with said chaml