US3592217A

US3592217A - Automatic pressure release valve

Info

Publication number: US3592217A
Authority: US
Inventors: Stanley E Keagle
Original assignee: EARLL Manufacturing CO
Current assignee: EARLL Manufacturing CO
Priority date: 1969-08-01
Filing date: 1969-08-01
Publication date: 1971-07-13
Anticipated expiration: 1988-07-13

Abstract

A fully automatic bottle and can crusher in which articles are fed, one at a time, into the crusher by a feeder. The feeder control is responsive to the presence of an article in the feeder, and the crusher control is responsive to the presence of an article in the crusher. The crusher is operated by an electrically actuated hydraulic release valve which discontinues operation of the crusher at a predetermined hydraulic pressure. The valve has a hydraulically actuated means for moving a spool to a pressure release position in response to the predetermined pressure.

Description

United States Patent Inventor Stanley E. Keaglc Minneapolis, Minn.

Appl. No 846,883

Filed Aug. 1, 1969 Division of Ser. No. 668,431, Sept. 18. 1967, Pat. No. 3,517,607

Patented July 13, 1971 Assignee Earl] Manufacturing Company Minneapolis, Minn.

AUTOMATIC PRESSURE RELEASE VALVE 17 Claims, 17 Drawing Figs.

U.S.Cl 137/115, 91/47,91/3l8,9l/356, 137/467 1111.01 ..G05dl1/00, Fl5b13/02 FieldolSeareh 91 47, 318, 356; 137 1 15,467

[56] References Cited UNITED STATES PATENTS 2,298,457 10/1942 Berges 91/318 3,232,172 2/1966 Ziegelmeyer v. 91/318 X Primary ExaminerLaveme D. Geiger Assistant Examiner-David J. Zobkiw Attorney-Burd, Braddock & Bartz ABSTRACT: A fully automatic bottle and can crusher in which articles are fed, one at a time, into the crusher by a feeder. The feeder control is responsive to the presence of an article in the feeder, and the crusher control is responsive to the presence of an article in the crusher. The crusher is operated by an electrically actuated hydraulic release valve which discontinues operation of the crusher at a predetermined hydraulic pressure. The valve has a hydraulically actuated means for moving a spool to a pressure release position in response to the predetermined pressure.

AUTOMATIC PRESSURE RELEASE VALVE CROSS-REFERENCE TO RELATED APPLICATION This application is a division of U.S. application Ser. No. 668,431 filed Sept. 18, 1967 now issued as U.S. Pat. No. 3,517,607.

SUMMARY OF INVENTION The invention relates to a pressure control mechanism responsive to a predetermined fluid pressure in a system to release the pressure in the system. The control mechanism is a valve having a body with a first cavity, a second cavity, and a fluid path connecting the first cavity with the second cavity. An inlet port opens to the path. A drain port opens to the first cavity. A valving member located in the first cavity moves to a first position to block fluid flow through the first cavity from the path to the drain port and moves to a second position to permit fluid flow through the first cavity thereby reducing the pressure in the path. A pressure-responsive valving means in the path operates in conjunction with a hydraulically actuated means located in the second cavity to move the valving member to its second position when a predetermined fluid pressure is attained in the path.

An object of the invention is to provide a self-contained automatic control valve operable in response to a predetermined pressure to release the pressure in a fluid system. Another object of the invention is to provide a pressure release valve wherein a predetermined release pressure can be adjusted. A further object of the invention is to provide a pressure release valve which is externally actuated and automatically returns to its initial operating position after a predetermined pressure is reached in the valve.

IN THE DRAWINGS FIG. 1 is a side view, partially cut away, of the crushing apparatus of the invention;

FIG. 1A is a side view of a portion of FIG. 1 during operation of the crusher;

FIG. 2 is a cross-sectional side view of one form of hydraulic control valve for use in the apparatus, the valve being in a pressure position;

FIG. 3 is a cross-sectional view of the valve of FIG. 2 in a drain position;

FIG. 4 is a cross-sectional side view of the valve of FIG. 2 in a standby position;

FIG. 5 is a bottom view of the valve of FIGS. 2-4;

FIGS. 6-10 are cross-sectional views of the valve of FIG. 3 taken along the respectively numbered lines;

FIG. 11 is a cross-sectional view of a modified valve for use in the apparatus, the valve being in a pressure position;

FIG. 12 is a cross-sectional side view of the valve of FIG. 11 in a drain position;

FIG. 13 is a bottom view of the valve of FIG. 11; and

FIGS. 1416 are cross-sectional views of the valve body of FIGS. 11 and 12 taken along the respectively numbered lines with the spool and other internal parts removed.

DESCRIPTION OF THE PREFERRED EMBODIMENT Crusher Structure The crushing apparatus is shown in FIG. 1. The articlecrushing means is here shown as a hydraulic crusher, generally designated 15, containing a bottle 16 to be crushed. Feeding means, generally designated 17, is positioned adjacent crusher 1S, and is adapted to feed articles to be crushed into crusher one at a time. A can 18 is disposed in a flexible chute 19 leading to feeding means 17 so that the lower edge of can 18 abuts a portion of feeding means 17. Chute 19 extends upwardly to a mouth, not shown, which may be mounted in the back portion of a bar or other place from which cans and bottles must be sent for disposal. Cans and bottles to be disposed of are dropped into the mouth of chute 19 and slide downward to the position of can 18. The crushing apparatus also includes a refuse container 20 which collects the broken and crushed pieces of bottles and cans. Container 20 is removable from the crushing apparatus for disposal of the crushed material.

Feeding means 17 includes an elevator platform 21 containing an elongated aperture 22 therethrough and downwardly extending end portions, one of which includes a vertical slot 56. Platform 21 is connected to a support post 23 which cooperates with a solenoid elevator operator 24. Support 23 includes a pair of hemispherical depressions 25 and 26 which cooperate with an adjusting screw 27, a bias spring 28 and a ball 29 to form a detent mechanism for retaining platform 21 in either a raised or lowered position.

The control means for feeding means 17 includes switching means, here shown as a'microswitch 30 of standard construction, having a switch operator arm 31 extending upwardly and terminating in a roller 32 positioned so that it extends through aperture 22 when platform 21 is in a lower position 33, which is shown in dotted lines. Switch 30 is connected to a source 'of power, not shown, and further connected in controlling relationship to solenoid 24. Depression of switch arm 31 closes a circuit which energizes solenoid 24 thereby raising platform 21 from lower position 33 to the upper position shown in FIG. 1 (solid lines).

Crusher 15 includes a lower stationary platen 39 which is rigidly connected to an upper stationary platen 40. Disposed between platens 39 and 40 is a movable platen 41. A hydraulic cylinder 42 is rigidly mounted to lower platen 39 and contains a hydraulic ram 43 which has its upper end attached to the underside of movable platen 41. Movable platen 41 is driven upward toward upper stationary platen 40 by hydraulic cylinder 43 during the crushing operation. Platen 41 is returned to its original position after the crushing operation by reset means, here shown as a return spring 44. A plurality of guide bolts 45 connect upper platen 40 to lower platen 39 in a predetermined, fixed, spaced relation. Movable platen 41 contains a plurality of guide holes through which guide bolts 45 are disposed to form guide means therefor as it moves up and down in the crushing operation. A stop member 46 is provided so that movable platen 41 returns to the same lower position after each crushing operation.

The control means for crusher 15 includes a switch 47, which may conveniently be a conventional microswitch, having an actuating arm 48 extending downwardly therefrom so that the lower end of arm 48 is disposed in the space between upper platen 40 and movable platen 41 when movable platen 41 is in the lower position. Electrically conductive leads 49 extend from switch 47 to a source of power, not shown, and to a solenoid 66 which controls a hydraulic valve, generally designated 65, so that actuation of switch 47 controls operation of solenoid 66.

Also included in the crushing apparatus is means for resetting feeding means 17 to position 33 while movable platen 41 is being reset to its lower position. This reset mechanism for feeding means 17 includes a latch bracket 50 which extends downwardly from movable platen 41. Rotatably attached to latch bracket 50 is a latch member 51. Attached to one end of latch member 51 is a latch bias spring 52 whose other end is attached to the lower side of movable platen 41. When movable platen 41 is in the position shown in FIG. 1, latch member 51 bears against a latch stop 53 which extends upwardly from stationary platen 39. A latch catch bracket 54 is rigidly attached to the depending end of elevator platform 21 adjacent crusher 15. Rotatably disposed in catch bracket 54 is a latch catch 55, and immediately above latch catch 55 is the groove 56 in the end of elevator platform 21.

. The hydraulic system of the crushing apparatus includes a hydraulic pump 60 which is mounted on top of a hydraulic fluid reservoir 61. Pump 60 is driven electrically from a source of power, not shown, and is turned on and off from a master switch, also not shown, which also controls the power to switches 30 and 47 and to

solenoids

24 and 66. Reservoir 61 contains a hydraulic fluid filter 62 which is connected to pump 60 by a pump intake line 63. From pump 60, a pressure supply line 64 extends upwardly to the hydraulic control valve 56, which is actuated by solenoid 66. A pair of leads 67 from solenoid 66 are connected to the source of power and to one of leads 49 of switch 47 by conductors, not shown. From valve 65, a ram supply and return line 68 extends to the bottom of cylinder 42. A pair of drain lines 69 and 71 extend downwardly from valve 65, joining into one line which empties into reservoir 61. The entire apparatus including crusher 15, feeding means 17, and the hydraulic system is mounted in a support structure 70, which supports the various portions and encloses the apparatus to prevent broken pieces of glass or other material'from escaping from the crushing area.

OPERATION OF CRUSHING APPARATUS Assume that the entire apparatus is empty of materials to be crushed. Elevator platform 21 will be in .dotted position 33 and movable platen 41 will be in the lower position, as shown in FIG. 1. The first piece to be crushed is fed into the mouth of tube 19 and slides downward in tube 19 and across the top of elevator platform 21 (which is flush withthe lower surface of tube 18) until it strikes the edge of movable platen 41 which is closest to elevator platform 21. The article is stopped by this leading edge of movable platen 41 and any articles behind it will be stopped by the upper end of the article to be crushed and the depending end of platform 21 as it rises. As the article slides over the upper surface of elevator platform 21, it strikes roller' 32 depressing arm 31 actuating switch 30. Actuation of switch 30 causes power to be supplied to solenoid 24 which then moves elevator platform 21 to the upper position as shown in FIG. 1. In the detenting mechanism, ball 29 is forced into depression thereby retaining platform 21 in the upper position even though pressure has been removed from roller 32 so that it returns to its normal position opening switch and removing power from solenoid 24.

While elevator platform 21 is in its upper position, the depending edge of platform 21 adjacent tube 19 forms an abut ment member which prevents further articles, such as can 18, from entering the feeding means while the previous article is being crushed.

When elevator platform 21 reaches its upper position, its upper surface is flush with the upper surface of movable platen 41 and the article to be crushed, such as bottle 16, slides downward onto platen 41. As the article reaches the opposite end of crusher 15, it engages arm 48 moving it and actuating switch 47. Switch 47, in turn, actuates solenoid 66 which actuates hydraulic valve 56 to a position wherein hydraulic fluid under pressure can be supplied through ram supply line 68 to hydraulic cylinder 42.

Hydraulic fluid is drawn from reservoir 61 through filter 62 and pump supply line 63 to hydraulic pump 60. Hydraulic fluid under pressure is supplied from pump 60 through pressure line 64 to valve 65 and through valve 65 to ram supply line 68. The hydraulic fluid causes ram 43 to be forced upward out of cylinder 42 thereby raising movable platen 41 upwardly along guide bolts 45 toward upper stationary platen 40. This upward motion of platen 41 crushes the article until a predetermined hydraulic pressure is reached in cylinder 42 and valve 65. At that time, valve 65 is actuated to a position which removes supply pressure from the hydraulic fluid in the cylinder 42 and provides a return channel through line 68 and valve 65 to drain line 69. Once the hydraulic pressure is removed'from ram 43, return spring 44 draws movable platen 41 back down to the lower position abutting stop 46, thereby forcing the hydraulic fluid back through line 68, valve 65 and drain line 69 to reservoir 61.

The latching mechanism provides a means for resetting elevator platform 21 to its lower position upon the return of movable platen 41 to its lower position. While movable platen 41 is in its lower position, latch member 51 is in a position with its leading edge retracted sufficiently to permit latch catch 55 to move upwardly past member 51 without engaging it. Latch catch 55 travels upwardly with elevator platform 21 as its rises to the solid position.

Catch member 55 is attached to bracket 54 in such a manner that it is rotatable from the position shown in FIG. 1 to a position in which the pointed edge of catch member 55 is vertically upward, but catch 55 is either biased or constructed so that as soon as the pressure rotating it upwardly is removed, catch 55 drops back to the position shown in H6. 1 where it stops. Thus, catch member 55 is rotatable through an angle of approximately 90 degrees and, in the absence of pressure from below, is in the position shown in FIG. 1.

As platen 41 moves upwardly, latch member 51 lifts off of stop member 53. Bias spring 52 then contracts rotating latch member 51 in a counterclockwise direction so that its upper leading edge extends outwardly toward latch catch 55. With continued upward movement, latch member 51 engages catch member 55 from the lower side and rotates member 55 upwardly until latch member 51 slides past catch member 55. Catch member 55 drops back to its original position, and latch member 51 continues to move upwardly with platen 41 passing through groove 56 inthe depending end of elevator platform 21 as is shown in FIG. 1A.

When movable platen 41 returns to its lower position, the outwardly extending end of latch member 51 temporarily engages the upper surface of catch member 55. The spring tension on bias spring 52 is great enough to maintain pressure on catch 55 and elevator platform 21 until ball 29 disengages from depression 25, whereupon elevator platform 21 drops back to its lower position 33 so that it is reset to feed in the next article to be crushed. As movable platen 41 approaches the bottom of its travel, latch member 51 again engages stop member 53 and is rotated in a clockwise direction to the position with the leading edge out of the line of travel of catch member 55.

Valve Structure FlGS. 2-10 Hydraulic valve 65, which controls the operation of crusher 15, also includes a novel structure which is shown in FIGS. 2 through 10. A valve body 74 contains a pressure inlet port 75, a ram supply and return port 76, a ram drain port 77 and a pressure drain port 78, which are best shown in FIG. 5. The remainder of the valve structure can best be seen by referring to FIGS. 2-4 and 6-10. Valve body 74 also includes a first cavity 79 in which a spool 80 is disposed. Body 74 also contains a second cavity 81 and a passageway 82 which connects

ports

75 and 76. A first interior port 83 connects one end of passageway 82 adjacent ram supply and return port 76 to spool cavity 79. A second interior port 84 connects a portion of passageway 82 adjacent pressure port 75 to spool cavity 79.

A first restricted passage 85 connects the opposite end of passage 82 to a valve chamber 86 within valve body 74, and a second restricted passage 87 connects valve chamber 86 with second cavity 81. The right end of passageway 82, restricted passage 85, valve chamber 86 and second restricted passage 87 provide a first fluid-conducting path between pressure inlet port 75 and second cavity 81. A restricted drain passageway 88 connects the right end of second cavity 81 with pressure drain port 78. Restricted passageway 88 provides a second fluid-conducting path in valve body 74. Further

interior drain ports

89 and 90 connect portions of spool cavity 79 to a passage 91 and ram drain port 77 and to a passage 92 and supply drain port 78, respectively. Valve body 74 contains a venthole 93 connecting one end of second cavity 81 with the outside atmosphere for equalizing pressure. Finally, a passageway 102 connects the adjacent ends of second cavity 81 and spool cavity 79.

A hydraulic spool-actuating means is provided in second cavity 81 by a piston 94 which is connected to an actuating rod 95. The end of actuating rod 95 remote from piston 94 extends through passageway 102. Disposed about piston 94 is an O-ring seal 96 to prevent hydraulic fluid from flowing into the portion of cavity 81 communicating with venthole 93. A bias mechanism, here shown as bias spring 97, is disposed between piston 94 and the wall of cavity 81 adjacent cavity 79. Spring Valve 65 also includes a hydraulic fluid pressure responsive mechanism which includes a valve closure member 98 disposed in valve chamber 86. Closure member 98 cooperates with a valve seat 99 formed in valve body 74 adjacent restricted passage 85. An adjustable bias means, here shown as a bias spring 100 and an adjusting screw are provided to vary the pressure with which closure member 98 is forced against seat 99.

Spool 80 has a first land 105, a second land 106 and a third land 107 separated from one another by

shank portions

108 and 109, respectively. Spool 80 further includes an exterior shank portion 110 and connecting means 111 which operatively connect shank portion 110 and spool 80 to solenoid 66. Disposed about

lands

105, 106 and 107 are O-rings 96 which prevent hydraulic fluid from leaking between ports or out of valve 65.

The hydraulic line connections to valve 65 are as follows: pressure port 75 is connected to the pressure supply line 64, ram supply and return port 76 is connected to ram supply and return line 68, ram drain port 77 is connected to drain line 69 and pressure drain port 78 is connected to drain line 71.

Valve Operation FIGS. 2-10 When an article to be crushed enters crusher and actuates switch 47, solenoid 66 moves spool 80 to the pressure position shown in FIG. 2. In this position, fluid under pressure entering through port 75 flows in passageway 82 to port 76, to

interior ports

83 and 84, and to restricted passage 85. The pressure generated on spool 80 at

ports

83 and 84 freezes spool 80 in that position even though energy is removed from solenoid 66. Hydraulic fluid flowing out of port 76 actuates hydraulic ram 43. At the same time, hydraulic pressure builds up in restricted passage 85 on closure member 98 which is preset to open at a specific hydraulic pressure, e.g. 500 p.s.i. Until that hydraulic pressure is reached, valve member 98 is firmly seated on seat 99 and no fluid flows through valve chamber 86.

As soon as the hydraulic pressure on closure member 98 reaches the predetermined value, closure member 98 cracks away from seat 99 and hydraulic fluid flows through chamber 86 and restricted passage 87 to the end of second cavity 81 remote from cavity 79. The pressure of fluid in cavity 81 forces piston 94 toward cavity 79 against the bias of spring 97. As piston 94 moves toward cavity 79, air is expelled from the portion of cavity 81 adjacent cavity 79 through vent hole 93. Actuating rod 95 moves through passage 103 and bears against the adjacent end of spool 80.

Motion of piston 94 toward cavity 79 causes spool 80 to be moved to the drain position shown in FIG. 3.

Restricted passages

87 and 88 are designed so that fluid pressure build up in cavity 81 as long as closure member 98 is off of seat 99. As soon as spool 80 moves to the position shown in FIG. 3, hydraulic supply pressure is removed from hydraulic ram 43 because interior port 84 communicates with interior port 90 through the portion of cavity 79 about shank portion 108 thereby allowing fluid under supply pressure to flow to drain port 78 without substantial resistance. At the same time, interior port 83 communicates with interior port 89 through the portion of cavity 79 about shank portion 109 thereby allowing fluid from cylinder 42 to flow to drain port 77 without sub stantial resistance. These interior communications provide two separate drain circuits for hydraulic fluid.

When valve 65 is in the drain position, pressure is removed from ram 43, return spring 44 and ram 43 exerts sufficient pressure on the fluid in cylinder 42 to force it back through pipe 68 and port 76 into valve 65. The hydraulic fluid flowing from port 76 continues upward through port 83, cavity 79, port 89, passages 91, drain port 77 and drain line 69 to reservoir 61. Fluid from pump 60 enters port 75 and flows through port 84, cavity 79, port 90, passageway 92, port 78 and drain line 71 to reservoir 61. As soon as valve 65 is in the drain position. fluid pressure valve member 98 drops and member 98 97 yieldably biases piston 94 toward the opposite end of cavity immediately reseats itself on seat 99. Fluid pressure in cavity 81 also drops, and bias spring 97 forces piston 94 away from cavity 79 expelling the fluid from cavity 81 through restricted passage 88 and drain port 78.

Fluid is expelled from cavity 81 until piston 94 reaches the end of its travel as shown in FIG. 4 leaving valve 65 in the standby position. In that position, valve 65 is ready to receive another actuating signal from solenoid 66 which will move spool to the pressure position shown in FIG. 2 again.

It can be seen that modifications can be made to the apparatus without departing from the contemplated scope of the invention. For example, normally open and normally closed switches and valves can be replaced by their reverse counterparts with suitable circuitry and bias reversals. Also, a suitable valving arrangement can be substituted for the simple restricted passage 88 to control expulsion of fluid from cavity 81 when fluid under pressure is removed therefrom. Other modifications will be apparent to those skilled in the art.

Valve Structure and Operation -FIGS. 11-16 A modified hydraulic valve is shown in FIGS. 11 through 16. This valve can be substituted for that shown in FIGS. 2 through 10 in the apparatus of the invention and is the presently preferred structure. The valve of FIGS. 11 through 16 is constructed and operates in a manner similar to that of the valve of FIGS. 2 through 10 with certain exceptions which are pointed out hereafter. Parts of the valve of FIGS. 11 through 16 which correspond to those of the valve of FIGS. 2 through 10 are numbered with corresponding numbers greater than the numbers on the valve of FIGS. 2 through 10.

An L-shaped passage 220 connects one end of valve chamber 186 to second cavity 181 and to a metered orifice 221 which communicates with restricted drain passageway 188. L-shaped passageway 220 and metered orifice 221 provide the fluid path between chamber 186, cavity 181, and passageway 188.

The means for actuating spool to its second position is a double-acting piston arrangement which provides snap actuation. Plston 194, which responds to the fluid pressure transmitted into second cavity 181, acts on a second piston 222 through a bias spring 223. Second piston 222 is attached to actuating rod and is biased to the right, as shown in FIG. 11, by bias spring 197. Second piston 222 is held in the position shown in FIG. 11 by a detent mechanism, here shown as a hemispherical depression 224 in the wall of piston 222 into which a ball 225 is forced by a bias spring 226. The detent mechanism retains piston 222 in the position shown in FIG. 11 until piston 194 is driven to the left by fluid pressure to release the detent mechanism either by pressure of spring 223 or by actual contact between

pistons

222 and 194. The pressure of spring 223 then forces piston 222 to the left rapidly and forcefully until it reaches the position shown in FIG. 12. This rapid forceful action causes positive snap actuation of spool 180 to the drain position shown in FIG. 12. The snap action of the valve of FIGS. 11 through 16 eliminates difficulties which are sometimes encountered because of the pressure seal holding spool 180 in its first position. A further structural modification necessitated by the double-acting piston is an additional venthole 193a communicating with the portion of second cavity 181 to the left of second piston 22.

A second drain passageway is provided to assist in draining fluid from hydraulic ram 43 when the valve is in the drain position. A second interior drain port 19011 is connected to a second ram drain port 1770 by an interior passage 191a. Ram drain port 1770 is connected to fluid reservoir 61 by a second drain line, now shown, Addition of the second drain port requires an additional shank portion 229 and

land surfaces

227 and 228 on spool 180. In all respects, other than those described above, the valve of FIGS. 11 through 16 is constructed and operates in the same manner as the valve of FIGS. 2 through 10.

The embodiments of the invention in which I claim exclusive property or privilege are defined as follows:

l. A valve comprising: a valve body having a plurality of ports including a load port; an inlet port communicating with a first interior cavity, the body further having a second cavity and a first fluid conducting path connecting the inlet port and the load port, and the inlet port and the second cavity; a first drain port communicating with the first cavity; a spool disposed in the first cavity and movable between first and second positions therein; pressure-responsive valving means disposed in the first path between the inlet port and the second cavity and biased in a first position until a predetermined fluid pressure within the path is exceeded, the valving means being movable to a second position by the fluid pressure when the predetermined pressure is exceeded thereby causing a change in fluid pressure in the second cavity; first spool-actuating means for moving the spool to its first position wherein communication between the first drain port and the first cavity is closed and fluid under pressure can flow through the valve from the inlet port in such a manner that fluid pressure increases at the pressure-responsive valving means; and second spool-actuating means for moving the spool to its second position wherein fluid under pressure can flow through the valve without significant fluid pressure increase in the first path, the second spool-actuating means being disposed in the second cavity, maintained in a first position while the pressure responsive valving means is in its first position, and movable to a second position in response to a fluid pressure change in the second cavity resulting from movement of the pressureresponsive valving means to its second position, the second actuating means being positioned so that it moves the spool to its second position upon movement of the second actuating means to its second position.

2. A valve according to claim 1 wherein: the plurality of ports includes a second drain port; and which further com prises fluid pressure relief means connecting the second cavity to the second drain port for relieving fluid pressure in the second cavity when the pressure-responsive valving means is in its first position.

3. A valve according to claim 1 wherein: the plurality of ports further includes a second drain port; the first path has a predetermined minimum diameter and communicates with a first portion of the second cavity, adjacent one end thereof; the pressure-responsive valving means including a valve seat formed by a portion of the wall of the first path, a valve closure member which, in the first position, cooperates with the seat to from a fluidtight seal, and which, in the second position has moved away from the seat thereby allowing fluid pressure in excess of the predetermined pressure to be transmitted to the second cavity, and adjustable biasing means cooperable with the closure member to yieldably bias the closure member in the first position; the valve body further includes a passageway directly connecting one end of the first cavity to the opposite end of the second cavity and a second fluid-conducting path connecting the first portion of the second drain port, the second path having a maximum diameter less than the minimum diameter of the first path; and the second spoolactuating means including piston means slidably positioned in the second cavity in fluidtight engagement with the walls thereof between the first portion and the opposite end, including a member operably connected to the piston means, slidably disposed in the passageway, and adapted to cooperate with the spool to move it to its second position when fluid pressure in excess of the predetermined pressure is transmitted to the first portion of the second cavity thereby moving the piston means toward the opposite end; and which further comprises yieldable bias means disposed in the second cavity between the piston means and the opposite end for moving the piston means away from the opposite end upon return of the closure member to the first position.

4. A valve according to claim 3 wherein: the spool includes an extension projecting through and outwardly from the valve body; and the first spool-actuating means includes a solenoid mounted coaxially with the extension and cooperable therewith to move the spool to its first position upon application of electrical energy to the solenoid, the solenoid being adapted for connection to a source of electrical energy.

5. The valve according to claim 1 including: means to bias the pressure-responsive means to its first position, and adjustable means for selectively varying the biasing force on the predetermined pressure can be adjusted.

6. The valve according to claim 1 including: holding means to releasably locate the second spool actuating means in its first position until a substantial increase in pressure in the second cavity overcomes the holding means to move the further second spool-actuating means to its second position.

7. The valve according to claim 6 wherein: the holding means comprises a yieldable detent acting on the second spool actuating means.

8. A valve comprising: a valve body having a plurality of ports including an inlet port, a load port at least one drain port communicating with a first interior cavity, the body further having a second cavity, a first fluid-conducting path connecting the inlet port and the load port, and the inlet port and the second cavity, the load port and inlet port communicating with said one drain port only through the first cavity, the inlet port being connectable to a hydraulic fluid supply, the load port being connectable to a hydraulic ram, and said one drain port being connectable to a fluid reservoir; a spool disposed in the first cavity and movable between first and second positions therein, said spool being constructed to block communication between the inlet and load ports and said one drain port in the first position and to allow communication therebetween in the second position; pressure-responsive valving means disposed in the first path between the inlet port and the second cavity and biased in a first position until a predetermined fluid pressure within the first path is exceeded, the valving means being movable to a second position by the fluid pressure when the predetermined pressure is exceeded thereby causing a change in fluid pressure in the second cavity; connecting means operatively connecting the spool to a solenoid so that actuation of the solenoid moves the spool to its first position wherein when the pressure-responsive valving means is in its first position fluid under pressure can flow through the valve from the inlet port to only the load port whereupon fluid pressure increases at the pressure-responsive valving mean; and

hydraulically actuated means for moving the spool to its second position wherein fluid under pressure can flow from the inlet port and the load port to at least said one drain port with out significant fluid pressure increases in said first path, the hydraulically actuated means being disposed in the second cavity, maintained in a first position while the pressureresponsive valving means is in its first position, and movable to a second position in response to a fluid pressure change in the second cavity resulting from movement of the pressureresponsive valving means to its second position, the hydraulically actuated means being positioned so hat it moves the spool to its second position upon movement of the hydraulically actuated means to its second position.

9. The valve according to claim 8 including: holding means to releasably locate the hydraulically actuated means in its first position until a substantial increase in pressure in the second cavity overcomes the holding means to move the hydraulically actuated means to its second position.

10. The valve according to claim 9 wherein: the holding means comprises a yieldable detent acting on the hydraulically actuated means. v

11. A valve comprising: a valve body having a first interior cavity, a second interior cavity, a fluid-conducting path open to the first cavity and the second cavity, and an inlet port and a load port communicating with the path, a drain port communicating with the first cavity, a movable valving member disposed in the first cavity movable in a first position to block the flow of fluid from the path to the drain port and movable to a second position to permit the flow of fluid from the path to the drain port, pressure-responsive valving means disposed in the path between the inlet port and the second cavity, said pressure-responsive valving means being maintained in a first position until a predetermined fluid pressure within the path is exceeded, the valving means being movable to a second position by the fluid pressure when the predetermined pressure is exceeded thereby causing an increase in fluid pressure in the second cavity, first actuating means for moving the valving member to its first position, second actuating means for moving the valving member to its second position wherein the fluid under pressure in the path can flow through the valve without significant fluid pressure increases in the path, said second actuating means being disposed in the second cavity and movable to a second position in response to a substantial increase in the fluid pressure in the second cavity resulting from movement of the pressure-responsive valving means to its second position.

12. The valve according to claim 11 including: means to bias the pressure-responsive valving means to its first position, and adjustable means for selectively varying the biasing force on the pressure-responsive valving means whereby the predetermined pressure in the path can be adjusted. C

13. The valve according to claim 11 including: holding means to releasably locate the second actuating means in its first position until a substantial increase in pressure in the second cavity overcomes the holding means to move the ac tuating means to its second position.

14. The valve according to claim 13 wherein: the holding means comprising a yieldable detent acting on the actuating means.

15. The valve according to claim 11 wherein said first actuating means includes: an external control member for moving the valving member to its first position.

16. The valve of claim 1] including: fluid pressure relief means connecting the second cavity to a second drain port for relieving fluid pressure in the second cavity when the fluid pressure responsive valving means is in its first position.

17. The valve according to claim 11 including: adjustable means for selectively varying the biasing force on the pressure responsive valving means whereby the predetermined pressure in the path can be adjusted.

P0-1050 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,592,217 Dated 1971 Inventor(s) Stanley H. Keagle It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 2, "56" should he 65.

line 29, after "31" andis omitted.

line 49 "56" should he -65" Column 4, line 1, "its" should be it-.

Column 5, line 48, "103" should he l(l2- line 52, "build" should he huilds. line 71, "passages" should he passage-.

Column 6, line 17, after "fluid", "under" should he omitted.

line 62 "22" should he -222- line 68, "now" should he --not-.

Column 7, line 46, "from" should be form.

line 55, after "the" -second cavity to the is omitted.

Column 8, line 5, after "on" the pressure responsive means whereby the is omitted. line 11, "further" should be omitted. line 17, after "load port" and is omitted.

line 42, "mean" should he means. line 45, after "port to", "at least" should be omitted. line 53, "hat" should he -that.

Column 9, line 19, after "adjusted." "C" should he omitted.

Signed and sealed this L th day of January 1 972.

emmy. 3

Attest:

EDWARD MJMJTGHEfQJl-l. ROBERT GOTTSGHALK Atte sting Officer Acting Commissioner of Patents

Claims

1. A valve comprising: a valve body having a plurality of ports including a load port; an inlet port communicating with a first interior cavity, the body further having a second cavity and a first fluid conducting path connecting the inlet port and the load port, and the inlet port and the second cavity; a first drain port communicating with the first cavity; a spool disposed in the first cavity and movable between first and second positions therein; pressure-responsive valving means disposed in the first path between the inlet port and the second cavity and biased in a first position until a predetermined fluid pressure within the path is exceeded, the valving means being movable to a second position by the fluid pressure when the predetermined pressure is exceeded thereby causing a change in fluid pressure in the second cavity; first spool-actuating means for moving the spool to its first position wherein communication between the first drain port and the first cavity is closed and fluid under pressure can flow through the valve from the inlet port in such a manner that fluid pressure increases at the pressure-responsive valving means; and second spool-actuating means for moving the spool to its second position wherein fluid under pressure can flow through the valve without significant fluid pressure increase in the first path, the second spool-actuating means being disposed in the second cavity, maintained in a first position while the pressure-responsive valving means is in its first position, and movable to a second position in response to a fluid pressure change in the second cavity resulting from movement of the pressure-responsive valving means to its second position, the second actuating means being positioned so that it moves the spool to its second position upon movement of the second actuating means to its second position.

2. A valve according to claim 1 wherein: the plurality of ports includes a second drain port; and which further comprises fluid pressure relief means connecting the second cavity to the second drain port for relieving fluid pressure in the second cavity when the pressure-responsive valving means is in its first position.

3. A valve according to claim 1 wherein: the plurality of ports further includes a second drain port; the first path has a predetermined minimum diameter and communicates with a first portion of the second cavity, adjacent one end thereof; the pressure-responsive valving means including a valve seat formed by a portion of the wall of the first path, a valve closure member which, in the first position, cooperates with the seat to from a fluidtight seal, and which, in the second position has moved away from the seat thereby allowing fluid pressure in excess of the predetermined pressure to be transmitted to the second cavity, and adjustable biasing means cooperable with the closure member to yieldably bias the closure member in the first position; the valve body further includes a passageway directly connecting one end of the first cavity to the opposite end of the second cavity and a second fluid-conducting path connecting the first portion of the second drain port, the second path having a maximum diameter less than the minimum diameter of the first path; and the second spool-actuating means including piston means slidably positioned in the second cavity in fluidtight engagement with the walls thereof between the first portion and the opposite end, including a member operably connected to the piston means, slidably disposed in the passageway, and adapted to cooperate with the spool to move it to its second position when fluid pressure in excess of the predetermined pressure is transmitted to the first portion of the second cavity thereby moving the piston means toward the opposite end; and which further comprises yieldable bias means disposed in the second cavity between the piston means and the opposite end for moving the piston means away from the opposite end upon return of the closure member to the first position.

8. A valve comprising: a valve body having a plurality of ports including an inlet port, a load port at least one drain port communicating with a first interior cavity, the body further having a second cavity, a first fluid-conducting path connecting the inlet port and the load port, and the inlet port and the second cavity, the load port and inlet port communicating with said one drain port only through the first cavity, the inlet port being connectable to a hydraulic fluid supply, the load port being connectable to a hydraulic ram, and said one drain port being connectable to a fluid reservoir; a spool disposed in the first cavity and movable between first and second positions therein, said spool being constructed to block communication between the inlet and load ports and said one drain port in the first position and to allow communication therebetween in the second position; pressure-responsive valving means disposed in the first path between the inlet port and the second cavity and biased in a first position until a predetermined fluid pressure within the first path is excEeded, the valving means being movable to a second position by the fluid pressure when the predetermined pressure is exceeded thereby causing a change in fluid pressure in the second cavity; connecting means operatively connecting the spool to a solenoid so that actuation of the solenoid moves the spool to its first position wherein when the pressure-responsive valving means is in its first position fluid under pressure can flow through the valve from the inlet port to only the load port whereupon fluid pressure increases at the pressure-responsive valving mean; and hydraulically actuated means for moving the spool to its second position wherein fluid under pressure can flow from the inlet port and the load port to at least said one drain port with out significant fluid pressure increases in said first path, the hydraulically actuated means being disposed in the second cavity, maintained in a first position while the pressure-responsive valving means is in its first position, and movable to a second position in response to a fluid pressure change in the second cavity resulting from movement of the pressure-responsive valving means to its second position, the hydraulically actuated means being positioned so hat it moves the spool to its second position upon movement of the hydraulically actuated means to its second position.

10. The valve according to claim 9 wherein: the holding means comprises a yieldable detent acting on the hydraulically actuated means.

13. The valve according to claim 11 including: holding means to releasably locate the second actuating means in its first position until a substantial increase in pressure in the second cavity overcomes the holding means to move the actuating means to its second position.

16. The valve of claim 11 including: fluid pressure relief means connecting the second cavity to a second drain port for relieving fluid pressure in the second cavity when the fluid pressure responsive valving means is in its first position.