US3230888A - Hydraulic auxiliary power unit - Google Patents

Description

Jan. 25, 1966 E. J. HAYES 3,230,888

HYDRAULIC AUXILIARY POWER UNIT Filed April 5, 1964 2 Sheets-Sheet l lE- v INVENTOR. 22 20472 J7 //4 ye s Jall- 1966 E. J. HAYES HYDRAULIC AUXILIARY POWER UNIT 2 Sheets-Sheet 2 Filed April 5, 1964 I INVENTOR. f wdr/ .7. flayes United States Patent 3,230,888 HYDRAULIC AUXILIARY PGWER UNIT Edward'J. Hayes, Livonia, Mich., assignor to Kelsey- Hayes Company, Detroit, Mich., a corporation of Delaware Y FiledApr. 3, 1964, Ser. No. 358,145

3 Claims. (Cl. 103-49) This application is a continuation-impart of my copending application Serial No. 100,373, filed Apr. 3,

1961, now abandoned.

This invention relates to a unit for pressurizing hydraulic fluid and transmitting it to hydraulically operated servo. devices such as hydraulically driven turbine type devices; used to develop electrical energy, and various othertypesof deviceshaving pistons or vanes movable under the,.= .influence of the hydraulic force to perform some work. This recitation of various uses for the unit herein disclosed is not meant by way of limitation of its inventive subject matter but merely as illustrative of the many uses to which such a device could be put. For example, the unit could be used to pump emergency supplies of oil or-fue1 to engines for relatively short periods of time. t f

Essentially, the pressurizing unit is a hydraulic fluid pump comprising a plurality of cylinders having movable members such as pistonstherein which are movable under the influence of applied or actuating gas pressure to exert force on other more dense fluids, and valve means which can alternatelyarid selectively transmit actuating gas to these movable members or pistons while simultaneously direct-ing the hydraulic fluid output of the cylinders to the servo device. The actuating gas is delivered to the cylinders by any of a number of devices such as solid fuel propellants which are capable of, producing relatively high gas pressures from a minimum of fuel volume, specificexamples of which are set forth below.

The importance of -this hydraulic fluid pumping unit arises from such exemplary results as the convertion of the force developed by relatively low density fluid to force developed by high density hydraulic fluid, the selfsufliciency-of the unit in developing its own pumping power, the compactness of the unit and its ability to provide a continuous flow of high pressure hydraulic fluid fora substantial time for emergency auxiliary operation.

It-is, therefore, a principal object of this invention to provide compact, self-containedapparatus for effectively utilizing the force developed by a relatively low density fluid to pressurize a relatively high density fluid.

Another object of the present invention is to provide fluid pressurizing apparatus operable to maintain the pressure of a hydraulic system at a desired level despite fluid losses in said hydraulic system. 1

A further object is to provide the above unit with electrical circuit means for automatically controlling the opera-ti'on'of the actuating pres-sure fluid and hydraulic output fluid flow in accordance with the power consumption of the servo device.

A further specific object of this invention is to provide a gas driven, self-sustained closed system auxiliary hydraulic fluid pumping unit with either mechanically or electrically operable valving means for con-trolling the gas and fluid flow to effectively provide hydraulic power without any exterior source of power or extraneous apparatus, which hydraulic fluid may be utilized in emergency situations to operate various types of servo devices.

Another object is to provide apumping unit of the above type which is capable of being started by the flow of actuating gas.

Further objects and advantages of the present inven- FIGURE 2 represents a side elevational view of the unit with certain parts broken away;

FIGURE 3 represents a cross sectional view of the unit taken along the line corresponding to 3-3 of FIG- URE 1; and

FIGURE 4 represents a schematic view of a typical electrical circuit for automatic-ally operating the power unit.

Referring to the drawings, the power unit is generally designated as 10 and comprises a top cover plate 12 and a bottom plate 14 secured together by a plurality of bolts 16 and compressing therebetween a pair of cylinders or chambers 18 and 20. Sealing rings 22 may be provided where necessary in order to make these chambers substantially fluid tight. Movable members or pistons 24 and 26 are sl-idahly mounted in chambers 18 and 20 respectively to provide in chamber 18 a servo section 28 and an actuating section 30, and in chamber 20 a servo section 32 and an actuating section 34. Suitable sealing rings 36 are provided on the pistons as necessary to insure a substantially fluid seal between the servo and actuating sections. At the inner portion of the cover plate 12 is provided a pair of servo fluid ports 38 and 40 serving sections 28 and 32 respectively, and in the outer portions of bottom plate 14 is provided a pair of actuating gas ports 42 and 44 serving actuating sections 30 and 34 respectively. A servo fluid control land valve 46 is secured to the top of plate 12 for directing the flow of fluid to and from the servo sections and the servo unit served thereby. This valve is provided with a bore 48 communicating through passages 50 and 52 with servo ports 38 and 40 respectively, with return flow passages 54 and 56 adapted for connection to the discharge port of a servo unit, and with a passage 58 connected to the inlet or feed port of said servo unit.

A solenoid 60 provided with an armature shaft 62 urged to the left by spring 64 is secured to the cover 12. Armature 62 is provided with sealing rings 65 at each end of valve 46, and with valving ridges 66 and 68 positioned on either side of passageway 58. It isobvious that as the solenoid coil "70 is energized and the armature 62 is pulled to the right to compress spring 64, ridge 68 will cooperate with land 72 to disconnect the servo section 32 from return flow passageway 56 while connecting servo section 32 with passageway 58 which feeds the servo device. Simultaneously ridge 66 will cooperate with land 74 to disconnect servo section 28 from feed passageway 58 and connect section 28 with passageway 54 receiving discharge fluid from the servo device. It is obvious that upon deenergization of the coil 70 of the solenoid, spring 64 will push shaft 62 to the left to connect servo section 28 to the servo feed passageway 58 while connecting servo section 32 to the passageway 56 receiving discharge fluid from the servo device.

Pistons 24 and 26 are alternately urged upwardly against the hydraulic fluid in their respective servo sections 28 and 32 by means of pressurized gas entening respectively into actuating sections 30 and 34 through actuating ports 42 and 44 respectively. For the purpose of clarification, it is mentioned here that as one piston moves up, the other moves down since the hydraulic fluid system comprising both servo sections, the servo valve and the driven servo device is closed. The motion of the pistons is controlled by an actuating fluid or gas land valve generally designated 76 which comprises a bore '78 having a gas inlet conduit 80 and a pair of grooves 82 and 84. The shaft 62 is extended into the bore 78 and is provided with a pair of v-alving ridges 86 and 88. Groove 82 is connected to actuating port 42 by a conduit 90 and groove 84 is connected to actuating port 44 by conduit 92. It is seen that as solenoid 60 is energized and shaft 62 is pulled to the right, gas inlet 80 will be connected to actuating section 34 while actuating section 30 is dumped to the atmosphere through bore 78.

With shaft 62 in the position shown in FIGURE 3 within the servo fluid and actuating fluid valves, it is seen that when pressurized gas is admitted to conduit 80 piston 26 will move upwardly to force hydraulic fluid in servo sect-ion 32 through passage 58 to the servo device, and piston 24 will be urged downwardly by the fluid being discharged from the servo device and flowing through passage 54 into the servo section 28. It is thus seen then that a see-saw type of piston motion will result.

The electrical circuit shown in FIGURE 4 controls the operation of solenoid 60 and thereby the flow of fluids to and from the servo and actuating sections. Since it is desirable in this device to get the most out of the gas pressure coming into inlet 80 of the'acuating fluid valve, the electrical circuit is constructed in such a way as to deenergize the solenoid coil 70 when piston 26 is substantially at the top of its stroke, and to energize the coil 70 when the piston 24 is at the top of its stroke. This is accomplished by allowing the pistons themselves to make and break the contacts which energize and deenergize the solenoid coil.

The electrical circuit of FIGURE 4 with components also shown in FIGURE 3, comprises a source of electrical energy such as storage battery or generator 94 for energizing the solenoid coil '70 adapted for connection to the source 94 across its terminals '71 and 73. A normally open switch 96 is provided with a pair of terminals 98 and 100 and a contact arm 102, which terminals are supported in the cover plate 12 inside of servo section 28 and which contact arm 102 is supported in electrically insulating material 104 in the piston 24. It is seen that as the piston 24 moves arm 102 into contact with the contacts 98 and 100, the solenoid 60 will be energized. Simultaneously with the energizing of solenoid 60 a reiay solenoid 106 will be energized to close a set of contacts 108 and 110 by a contact arm 112 Matched to the armature 114 of the solenoid 106. The connecting of contacts 108 and 110 will energize a second relay coil 116 which will cause its armature 118 to move contact arm 120 into contact with contacts 122 and 124. A contact arm 126 inside of servo section 32 is normally held into contact with contacts 128 and 130. It is seen, therefore, that after piston 24 has moved contact arm 102 upwardly to energize the solenoid 60 and hydraulic fluid starts flowing in the reverse direction back into servo section 28, the connection between contacts 98 and 100 will be broken by the downward motion of piston 24. However, solenoid 60 will remain energized through the holding circuit of relay coils 106, 116 and normally closed switch 126 in servo section 32. As piston 24 moves downwardly toward the end of its stroke and servo section 28 becomes filled with hydraulic fluid, piston 26 moves upwardly forcing hydraulic fluid out of section 32 until a contact breaking post 132 supported in electrically insulated material 134 on the piston 26 engages contact arm 126 and breaks the electrical connection between contacts 128 and 130. When this occurs, solenoid 60 will be deenergized, shaft 62 will move to the left to reverse the flow of actuating and servo fluids and again start piston 24 on its upward motion and piston 26 on its downward motion. It is obvious that the rapidity of up and down motion or cycling of the pistons 24 and 26 will depend upon the resistance to flow of the hydraulic fluid from the servo sections and the pressure of the actuating fluid in sections 30 and 34.

The actuating pressure fluid may be supplied by any conventional gas pressure developing means such as a solid propellant charge 136 in container 138 which charge may be ignited by an electric arc between electrodes 139 and 140 or by a small explosive ignition charge (not shown) placed adjacent this arc. There are several types of propellant charges which may be used such as the LFT series of solid propellants sold by Standard Oil of Indiana. It is obvious that other gas-producing means could be used such as those which depend upon the release of gaseous products from the chemical reaction of separate chemical components. The use to which the unit is to be put will determine the size and chemical nature of the gas producing charge.

During the fraction of a second which it takes the pistons to reverse their directions of travel, it may be desirable to provide some means such as accumulator 142 which stores fluid in its chamber 144 held under compression through spring 146 or by gas trapped in chamber 147. As fluid pressure is needed during -the aforesaid fraction of a second, the fluid in chamber 144 of the accumulator will be forced out through the port 146 which is connected into the servo device feed port 58. A vent 148 is provided in the bottom of the accumulator housing to allow spring'146 to be compressed. It is obvious that many types of conventional accumulat-ors would find utility in this regard.

The illustrated electrical circuit of FIGURE 4 is one of many diflerent arrangements which would find utility in controlling the operation of the solenoid 60. Persons skilled in the art could readily devise a great number of circuits using various normally open and normally closed switches as variations of the normally open and closed switches 96 and 126 shown by applicant.

A pressure relief valve 150'may be provided to limit the maximum gas pressure admitted to sections 30 and 34. This valve comprises a valve disc 152 urged against port 154 by a spring 156. Chamber 158 of this valve communicates continuously with the inlet conduit 80 through the valve bore 78.

The leads 139 and 140 of the charge ignitor may be connected to any electrical power source such as battery 94 and to any electrical switch properly located for actuation either manually or automatically when the auxiliary power is required; For example, if the unit were used to drive an auxiliary electrical generator, the 'leads'139 and 140 could advantageously be connected to a switch which would be closed upon failure of the primary generator.

As mentioned above, the type of servo unit operated by applicants pumping device may be varied, and in FIGURE 3 a turbine 160 is schematically shown. This turbine may be provided with a fluid inlet 162 for connection to the feed port 58 of the valve 46; andwith a branched fluid discharge 164 for connection to the return ports 54 and 56 of the valve 46. An output shaft and pulley arrangement 166 may be connected to-''- an electrical generator, for example, to provide emergency auxiliary electrical energy.

In the event of fluidlo-sses-in the system or mechanism pressurized by the apparatus of the presentsystem (.such as the turbine 160), it will be apparent that insuflicient fluid will flow into the servo sections 28 and 32 on the downward strokes of their pistons 24 and 26 to completely fill the chamber 18 and 20. When this happens the pistons 24 and 26 will not descend completely in the chambers 18 and 20, but only enough to accommodate the recirculating hydraulic fluid. The reason for this is that light weight return springs 168 and 170 bear against the bottoms of the pistons 24 and 26 to keep them from descending in the absence of some force or weight hydraulic fluid. It is also believed possible to eliminate the nee-d for the springs 168' and 170 by inverting the entire structure so that as hydraulic fluid enters the chambers 18 and 20 at the bottom thereof,

gravity will oppose movement of the piston toward the actuating sections. Accordingly, when each piston begins its upward pumping stroke there is no Waste or lost motion in which a piston is not actually working against hydraulic fluid.

While it will be apparent that the preferred embodiment of the invention disclosed is well calculated to ful fill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. In a recirculating hydraulic system having a servo unit operated by pressurized hydraulic fluid, emergency hydraulic fluid pressurizing apparatus including means defining a pair of chambers, a pair of independently operable movable walls disposed one in each of said chambers and dividing each chamber into servo and actuating sections, servo valve means connecting said servo sections to said servo valve and said servo valve to said servo unit for the selective flow of hydraulic fluid between said servo unit and said servo sections, a gas generator, 2. gas valve, means connecting said actuating sections to said gas valve and said gas valve to said gas generator for the selective flow of fluid from said gas generator to said actuating sections, switch means operated by said movable walls upon the reciprocation thereof toward said servo sections to operate said valves, said walls being movable in one direction under the influence of gas from said generator to pump fluid in the servo sections adjacent thereto and being movable in the opposite direction only in response to the return fiow of fluid into their adjacent servo sections from said servo unit.

2. The structure set forth in claim 1 including means normally biasing each of said movable walls toward their adjacent servo sections.

3. The structure set forth in claim 1 including a spring in each of said chambers operable to bias each of said Walls in a direction toward its adjacent servo section.

References Cited by the Examiner UNITED STATES PATENTS 212,039 2/1879 Molera et a1. 54 494,782 4/ 1893 Jewell 6054 584,620 6/1897 Battey 6054 657,160 9/1900 Eads 10352 1,216,664 2/1917 Dodd 6054 1,487,946 3/1924 Johnson 10352 2,366,417 1/1945 MacMillin 10349 3,046,898 7/1962 Badenoch et a1. 10349 DONLEY I. STOCKING, Primary Examiner.

Claims (1)

1. IN A RECIRCULATING HYDRAULIC SYSTEM HAVING A SERVO UNIT OPERATED BY PRESSURIZED HYDRAULIC FLUID, EMERGENCY HYDRAULIC FLUID PRESSURIZING APPARATUS INCLUDING MEANS DEFINING A PAIR OF CHAMBERS, A PAIR OF INDEPENDENTLY OPERABLE MOVABLE WALLS DISPOSED ONE IN EACH OF SAID CHAMBERS AND DIVIDING EACH CHAMBER INTO SERVO AND ACTUATING SECTIONS, SERVO VALVE MEANS CONNECTING SAID SERVO SECTIONS TO SAID SERVO VALVE AND SAID SERVO VALVE TO SAID SERVO UNIT FOR THE SELECTIVE FLOW OF HYDRAULIC FLUID BETWEEN SAID SERVO UNIT AND SAID SERVO SECTIONS, A GAS GENERATOR, A GAS VALVE, MEANS CONNECTING SAID ACTUATING SECTIONS TO SAID GAS VALVE AND SAID GAS VALVE TO SAID GAS GENERATOR FOR THE SELECTIVE FLOW OF FLUID FROM SAID GAS GENERATOR TO SAID ACTUATING SECTIONS, SWITCH MEANS OPERATED BY SAID MOVABLE WALLS UPON THE RECIPROCATION THEREOF TOWARD SAID SERVO SECTIONS TO OPERATE SAID VALVES, SAID WALLS BEING MOVABLE IN ONE DIRECTION UNDER THE INFLUENCE OF GAS FROM SAID GENERATOR TO PUMP FLUID IN THE SERVO SECTIONS ADJACENT THERETO AND BEING MOVABLE IN THE OPPOSITE DIRECTION ONLY IN RESPONSE TO THE RETURN FLOW OF FLUID INTO THEIR ADJACENT SERVO SECTIONS FROM SAID SERVO UNIT.

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