US2292278A - Pressure system - Google Patents

Description

ug. 4, 1942l W. LORENZ PRESSURE SYSTEM Filed Aug. l5, 1939 Willllllu Patented Aug. 4, 19f12 PRESSURE SYISTEM Walter Lorenz, Dessau, Germany, assignor to Junkers Flugzeug-und-Motorenwerke Aktiengesellschaft, Dessau, Germany, a corporation of Germany Application August 15,1939, Serial No'. 290,203

In Germany August 18, 1938 3 Claims.

Aor pneumatic pressure.

`For instance, for various airplane parts, such as retractable landing gear, wherein two separate parts, or halves, are includedin one system but are operated by -separate actuating devices, it-

is very desirable that they move simultaneously and equally. In most systems it is very difficult, if not impossible, to accomplish this, due to' the fact that diiierent resistances must be overcome by eachv actuating means and the `norma1 tendency is for the device against which least resistance is exerted to move first. This is naturally always the case when the system is so arranged that the actuating means operate in parallel; and moreover i'n systems so arranged it is generally deemed necessary to provide volume distributors to equalize the iiows to the different actuating means. -There are also objections to a system wherein the actuating means operate4 in series, not the least of which is that the displacement in all the actuating means must be the same; or again, in a hydraulic system, if air should be present in the line between two actuating means arranged in series, due to its compressibility, it will very probably prevent the second part to be moved reaching the end f its movement, so that any locking device provi-ded to retain that secondpart in its end position cannot function, 'due to the fact `that that position is not quite reached Y It is an object of this invention to provide a pressure system wherein the aforementioned drawbacks are overcome, and wherein means are provided for operatingv a p'lurality of actuating means simultaneouslyand substantially equally even if the resistances to be overcome by the separate' actuating means differ materially. Another object of the invention is to provide a pressure system wherein the separate actuating means are normally operated in series, and wherein means ar'eprovided for automatically switching the device tol operate in parallel by -excessive pressure vbuilt up in one of the feed lines; :thereby providing a pressure system wherein less pressure is required than when operating only in series, and at the same time eliminating the necessity for volume distributors above referred to.

LAA further object of the invention is to provide an equalizing valve -for such pressure systems wherein means are provided for normally permitting the passage of liquid, or uid, displaced from one cylinder to ow to another so that the pistons therein may be operated in series; wherein automatic n --ans are provided for connecting the feed line men in use directly to the second cylinder as soon as excessive pressure is built up in that feed line; and wherein means are provided for automatically resetting the equalizing valve so that series operation of the cylinders again results as soon as a suicient drop occurs in the feed line.

Having thus briefly and broadly stated some of theobjects and advantages of the invention I -will nowproceed to describe a preferred embodiment thereof, with the aid of the accompanying drawing, in which y Figure 1 illustrates a lay-out of my pressure system.

liigurelZ` is an enlarged detail `in section showing the operating valve, and p Figurek 3-is an enlarged view, partly in section, showing the equaliz'ing valve.

Referring to the drawing, I .designates a reservoir intended to contain suitable liquid, which is connected by a pipe 2 to a pump 3 the discharge from whichuis delivered'through'a Iline 4 which p terminates in a valve 5 to which pipes 6, l and 8 are also connected. Extending from the pipe 6 are two branches 9 and ll, theformer terminating in one extremity of a Acylinder i9, and the latter in an equalizing vvalve `l2;4 Similarlytwo y former 'to the equalizing valve lI2 andthe latter.,

to one extremity of'a cylinderUlSL The pipe 1 extends from the valve 5 back to the reservoir l.

Thus by turning the operatingjvalve thepump discharge may be selectively connected to' either pipe ly or 8, and the other pipe ilL 0r6 connected to the reservoir I. "y

Provided inthe cylinders 4llland ll5* arepistons I6 and I1 whichv divide these cylinders' 4into chambers I8V and i9, and 2U and 2l respectively.` Extending from the ends of the cylinders I0 and I5 remote from the pipes 9 and I4 are lines 22 and 23 respectively which are normally connected to one another through the equalizing valve l2 so that liquid displaced from the chamber I9 of the.

cylinder In flows into the chamber 2o of the cylinder |15 upon admission of liquid underpressure through the pipe 9 into the chamber i8 vided in the latter are two spaced parallel plungers 25 and 26 the extremities 29 and 30 of which CII a sleeve 38a depending from the valve body andv forming a part thereof.

Provided in the body of the valve I2 at right angles to the axes of the plungers `and 26 are three passages 34, 33 and 35. The passage 34 terminates at opposite ends in the bores wherein the said plungers are mounted and somewhat above the latter when they are in their lowered positions; The passage 33 extends through the valve I2 in valignment with the normal positions of the plunger grooves 21 and 28, and is connected to the passage 34 by an aperture 3S formed in the body of the valve. The passage also extends transversely through the body of the valve and is connected at its extremities, either exteriorly of the valve as shown in Figure 1, or within the latter as shown in Figure 3, to the lines 22 and 23.v Extending through the valve body' from the passage 35 is an outlet 31 from which a line 24 extends back to the reservoir I, and connecting the said outlet with the lower portions of the bores wherein the plungers 25 and 26 are mounted are suitable apertures 31a.

As the detailed arrangement of the plungers 25and 26 and their coacting parts is identical I will now describe the arrangement relative to the plunger 25 with the aid vof Figure. Projecting upwardly from the plunger 25 and having a shank in threaded engagement therewith is an insert o! smaller diameter than the said plunger, and having an annular retaining wall 48a upon its upper face to encircle a ball 4|. Mounted for axial movement in the bore 26a coaxial with the plunger 25 is a hollow auxiliary plunger 42 the lower portion of which is a good sliding iit around the insert 40. Formed integral with the said auxiliary plunger intermeare normally retained towards the extremities of through the branch I4,l pipe8, valve 5 and pi'pe 'I to the reservoir I. However, if excessive pressure is built up in the branch II this pressure overcomes the tension of the springA 3| by exerting pressure upon the top of the flange 42a and forcing the auxiliary plunger 42 downward until its flange 42h contacts the shoulder formed around the lower end of the enlarged portion of the bore 25a, by which time the said auxiliary plungery has moved downward suiiciently to close the aperture 44, which normally prevents an accumulation of pressure beneath the said ange 42a. Then the pressure unseats the ball 4I and the liquid flows beneath the annular flange 42a and exerts pressure upon the insert 40 and forces the latter downwardly in the bore of' the auxiliary plunger 42 until the said insert is free from the latter, whereupon the liquid exerts pressure directly upon the top of the plunger 25 and forces it down suiiciently to open the passage 34. As the plunger 26vhas meanwhile remained stationary the liquid then ilows from diately of its length is an annular flange 42a the underside of which is normally seated upon the ball 4| by a spring 43 extending between the top of the said flange 42a and the adjacent end of I the bore 25a. The upper extremity of the said l;

bore 25a is of increased diameter to receive an external flange 42b formed around the upper extremity of the auxiliaryplunger 42 and limit the axial movement of the latter. Formed radially through the said plunger 42 beneath the annular ange 42a is an aperture 42e which is adapted to register with an opening 44 formed isi; the valve body and connected to the outlet The operation of the system is as follows: When the operating valve is in theposition shown in Figure 1 liquid under pressure is delivered from the pump 3 through the pipe 6 to the branches 9 and II. The liquid delivered into the chamber I8 causes movement of the plunger I6 thereby displacing the liquid in the chamber I9 and discharging it through the line 22, the passage 33 and grooves 21 andv 28 and the line 23 to the chamber 20, thereby moving the piston I1 and discharging the liquid from Vthe chamber 2| the passage 34 through the aperture 36 to the passage 33, Aaround the annular groove 28, and through the line 23 to thel chamber 20.

Due to the fact that the eiective area of the insert 48 against; which pressure is .exerted while within the auxiliary plunger 42 is less than the effective area of the plunger 25 against which pressure is subsequently exerted, greater pressure is required to move the plunger in its former stage than in the latter. In this way provision is made for obtaining rapid and sensitive movement of the plunger 25 during the nal part of its movement; and again, due to this arrangement the system will continue to work in parallel even after a slight drop in pressure due to the increased 'eilective area of the plunger 25 upon which pressure is then being exerted. However when a sufdcient drop in pressure exerted through the pipe II occurs the spring 3| again raises the plunger 25 to its normal position so that the equalizing valve I2 is automatically returned to such position that the system again j operates in series. It will also be noted that when 'through the line 23, the valve lz, and une 2z to the chamber I9; and from the chamber I8 back to the reservoir I through the pipes 9, 6 and 1 and the operating valve 5. 1f excess pressure is built up in the branch I3 the operation of the plunger 26 is similar exactly to the operation of. the plunger above described. v p

While the preferred embodiment of the invention has been described and shown it is understood that this system nfay be adapted to include any desired number of workingv cylinders, and that the construction shown is susceptible to such alterations and4 modifications as fall wit-hin the scope of the appended claims; and while throughout the description mention has been made of the use of liquid, it is understood that the system can be equally successfully operated by other fluid under pressure.

What I claim is:

\ and having additional ports, a source of fluid .under pressure, a main operating valve vconnected thereto, pipes connecting said main operating valve with the other port of each cylinder and with the source of fluid, a branch extending from each of said port-connecting pipes to one of said additional ports of the equalizing valve device, said device including passages connecting each branch-connected port with the main passage therein, a pair of valves in the equalizing valve device each cooperating with one of the cylindernected ports thereof, spring means biasing each of said last-named valves normally to keep the cooperating cylinder-connected port of the equalizing `valve device open and` the cooperating branch-connected port closed for series operation of the pistons and yieldable at predetermined pressure in the corresponding branch whereby one valve of said last named. valves will move tovclose the cooperating cylinder-connected port and open the cooperating branch-connected port and its connection to the main passage for parallel operation of the pistons, and means foradjusting the spring means to vary the pressure in said branch at which said one valve operates.

connected ports of the equalizing valve device and with one of the branch-connected ports thereof, and means biasing each of` said lastnamed valves normally to keep the cooperating cylinder-connected port of the equalizing valve device open and the cooperating branch-connected port closed for series operation of the pistons and yieldable at predetermined pressure in the corresponding branch whereby one valve of said last named valves will 'move to close the cooperating cylinder-connected port and open the cooperating branch-connected port and its connection to the main passage for parallel operation of the pistons.

2. A pressure mechanism for simultaneouslyl operating a plurality of, control devices comprising a pair of cylinders each having a piston and having ports at its opposite ends, an equalizing valveA device having ports connected' to a port of each cylinder and a main passage normally placing said latter cylinder ports in communication and having additional ports, a source of lluid under pressure, a main operating valve connected thereto, pipes connecting said main operating valve with the other port of each cylinder and with the source of fluid, a branch extending from each of vsaid port-connecting pipes to one of said additional ports of the equalizing valve device, said device including passages connecting each branch-connected port with the main passage therein, a pair of valves in the equalizing valve device each cooperating with one of the cylinder-connected ports of the equalizing ing from a predetermined higher pressurevin valve device and with one of the branch-con- 3. A pressure mechanism for' simultaneously operating a plurality of control devices comprising a pair of cylinders each having a piston and having ports at its opposite ends, an equalizing valve device having ports connected to a port of each cylinder and a main passage-normally placing said latter cylinder ports in communication and having additional-ports, a pump for fluid, a main operating valve connected to the discharge of said pump, pipes connecting said main operating valve with the other port of each cylinder and with the source of iiuid, a branch extending from each of said port-connecting pipes to one of said additional ports of the equalizing valve device, said device including passages connecting'each branch-connected port with the main passage therein, a pair of valves in the equalizing valve device each cooperating with one of the cylinder-connected ports of the equalizing valve device and with one of the branch-connected ports thereof, means biasing each of said last-named valves normally to keep the cooperating cylinder-connected port of the equalizing valve device open and the cooperating branchconnected port closed for series operation of thev from the equalizing valve device to the'intake of said pump normally closed by the valves in said deviceand adapted to be opened by further movement of either oi' said last-named valves resulteither of the. branches.

WALTER LORENZ.

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