US2444474A

US2444474A - Fluid pressure device

Info

Publication number: US2444474A
Application number: US538976A
Authority: US
Inventors: Howard E Somes; Benjamin R Purvin
Original assignee: Ohio Crankshaft Co
Current assignee: Ohio Crankshaft Co
Priority date: 1944-06-06
Filing date: 1944-06-06
Publication date: 1948-07-06
Anticipated expiration: 1965-07-06

Description

July 6, 1948. H. E. soMEs ETAL 2444474f FLUID PRESSURE DEVICE l Filed June 6, 1944 2 Sheets-Shee1'I 2 INVENT Howard E' Some Benjam z'n R Pa rz/z'n Patened July 6, 1948 cuirso s mrss TEN T ffOF'FICE 'to Thie* Ohio =Crankshaft Company, Cleveland,

Ohio, afcorporation of Ohio Application June '6, 1944, Serial No. 538976 `This vinvention relates 'to re'ciprcca'ble work 'suppor'ting carriages and the like, 'particularly `vto 'devi'e's of this nature adapted to be reciprocated i'n `generallyvertica1 V'dir'ection through the me- 'diuin of a fiu'id under pressure.

In various types of rn'ech'an'isms, such as for example, machine tools, heat treating equipment and the like, a carriage or head is frequently caused to recip'rocate i'n a 'generally Vertical 'di- 'rect'ion through the provision of 'fluid pressure cylinders and pistons. Particularly, in construc- 'tions of this Character wherein the carriage or head and the work or tool carried thereby is severalliundred pounds 'in weight, serious damage 'to 'the'equipment is likely to result in the event the ifluid pressure 'should 'fail when the lcarriage or head is 'in an "elevate'd position.

'The object of 'the present invention is to -provide a generally Vertical fiuid *piston andcylinder iarran'ge'inent 'of novel 'construction wherein 'improved means is provided for preventing relative inoveinent between the parts inthe event of fluid pressure failure.

Another 'object 'is the provision in 'a cylinder and piston arrangeinent adapted to be relatively reciprocatecl 'by fiuid 'under pressure of 'a novel and 'ir'nproved lcheck valve arange'rnent 'which duic'kly and 'automatically functions to 'prevent relative reciprocation of the parts in the `'event *of lfiiiid pressure failure.

With the above 'and jo'ther objects in view which will be 'apparent from the 'following description'to those 'skilled in theart `to which the invention appertains, 'the present invention vvconsists in certain features of construction and 'co'rribinations of parts to b'ehereinafter described 'with reference to the accor'npanying drawings, and then claimed.

In the drawings which illustrate bodimen-t of the inventio'n:

Figure l is a front elevation of a heat treating machine having Va vertically reciprocable carriage in which the features'of the present inventio'n 'are in'ccrporated;

Figu're 2 is an *enlar'ged lon'g'itudinal section of a p'o'rtion of one of the carriage actuating cylinders 'and 'pistons Fgures 3, 4, and aretransverse'sectionstaken `'s'ubtariti'ally 4on the lines 3 -3, 4-44, and `5--5, respectively, of 'Figure 2,'

Figures G'an'd 7 are'diagrammatic 'views show- *i'ng ztwo sta'ges of operation of the cylinder and a suitable em- "pi'sytc'n arrangernent and "Figf is a section through antinterlocking relief *Valve 5 iClaims. (Cl. 121-'--40) 2 Referring to the -drawings, the machine 'selected for il'lustration is a 'heat "'trea'ting machine 'adapted to heat treat the bore of an elongated cylindrical member lt which is moved ve'rtically and longitudinally by the reciprocah'le Ycarriage, generally designa'te'd i I, Irelative t-oheatin'g and quen'ching 'heads tE and IS, i'espectively.

The 'carriage 'I'l einbo'dies 'spaced Vertical oylyinders l'f interconn'e'cted 'by spaced 'cross heads i and 'HS which carry chu'cking Vmembers "I'! ``for holding ithe tubular member *NJ lin axi'al alignm'ent -with the heating and 'quenching heads FZ and 13. The ca'rriage cylinders till 'are 3recip'rocabiy supported ion spaced Vertical rods W `ysecuredi'by suitable clamps 19 'toithe 'iiia'chine base 2'9.

The rcds 133 farfe prefer'ably comprisedfo'ffafsolid intermediate section '2| fan'd tubula'r upper "and lower. Sections "22 having 'tapered ``te'lescopirig '-"fi'ts 'as -in'dicated at 23 in Figure 2, 'the intermediate section being provided 'With `'coupling co-llars124 labutting Shoulders '25 "afnd th're'adefd'to the tubu- -lar upper and lower Sections `2 I.

The 'intermediate section 22| -is provided With an enlarged por'tion 26 substantially n'ridwiay between theends 'of the r'od 1i8 with which the cylinder Hi lhas Vsealedsliding engagement. H1- though'not shown in Figures .1. andfiz Aof 'thedrawings, 'the opposite ends -of the cylinders ih'ave sealed sliding engagement with the rod/sections v22.

The intermediate section 2| is provided with two longitudinal passages *Z' and 28, the passage '2"i opening -into the cylinder space -abo've `the piston portion 328 through portl!! which is ``closed by the check valve 30, shown in ``Figure 3, -and the passage 28 opening into the cylinder space below 'the =p`iston portion 2B through ports 73'I.

passage 34 which opens 'through'the seat 33. =Arranged 'above the seat 33 and 'intersecting the passage 32 is a cross passage35 whichplacesthe passage 32 in 'communication fwith -thecylinder space above the `pistonportion '28. Disposed in the passage 3'2 is a longitudinall'y imovable slide spaced

intermediate piston portions

38 and 39 and an upper shank portion 40 surrounded by a compression spring 4|. Threaded in the upper end of the passage 32 is a plug 42 having a recess 43 Within which the shank portion 40 is adapted to slide. The compression spring 4| abuts the plug 42`and the piston portlon 39 and urges the valve 36 downwardly whereby the lower portion 31 engages seat 33 to halt movement by the spring. In this position of the valve, the spaced

piston portlons

38 and 39 are disposed as seen in Figure 2 at opposite sides of the cross passages 35. The high pressure passage 21 is also provided with a passage 44 which opens into the passage 32 between the

piston portions

31 and 39.

Figure 6 diagrammatically illustrates the fluid fiow to one of the cylinders |4 (the upper) during elevation of the carriage Fluid under pressure flowing through the high pressure passage 21 opens the check valve 30 and flows through passage 29 into the upper end of the cylinder. A passage 45 is provided for draining leakage fiuid from the passage 32 above the valve 36.

The fluid control system -is so arranged that under normal operation a predetermined pressure is maintained in the low pressure passage 28 during the up stroke of the cylinder |4 and in the event of a drop in pressure in the line 21, the pressure in passage 28 will drop below the predetermined value. This pressure in passage 28 in normal operation is such that upon initial upward movement it will raise the slide valve 36 from its seat to the position shown in Figure 6, thus plaoing the cross passages 35 in communication with each other.

During the downward movement of thevcarriage, as depicted in Figure '1, low pressure fluid flows through passage 28 and thence through passage 3| into the lower end of the cylinder to cause the downward movement. This fiuid is under suflicient pressure to flow through passage 34 and keep the slide valve 36 raised from its stop seat against the resistance of the spring 4| which keeps the

passages

35 and 44 in communication with each other whereby the fluid in the upper end of the cylinder flows through these passages and thence through passage 21 back to the source of fluid supply. During this movement, the check valve 30 maintains the passage 29 closed.

Should the fluid pressure in passage 28 fall, incldent to fluid -line breakage to either conduit 21a, or 28a, pressure pump failure or any other cause, during either upward or downward movement of the carriage and drop below the predetermined value necessary to overcome the resistance of the compression spring 4|, the compression spring 4| immediately moves the slide valve 36 downwardly to its seat 33, this being the position shown in Figure 2. The valve portion 39 thus closes passage 32 between the

passages

35 and 44. Also, under the condition of a drop'in pressure in the high pressure line 21 the check valve 30 closes communication between the

passages

21 and 29, just as it does for all return flow from the cylinder to the passage 21.

The fluid 'in the upper end of the cylinder |4 which normally flows back to the source through passage 21 is thus trapped in this end of the cylinder and accordingly prevents the cylinders and the carriage supported thereby from dropping and causing damage to the mechanism or the work or tools supported by the carriage.

VTo summarize, in normal operation as long as and 44 working pressure is maintained in the passage '21 the pressure in passage 28 is permitted to remain at least high enough to hold the valve 36 in its upper .position against the spring 4|' and the

passages

35 and 44 are continuously kept in communication with each other. Under these normal conditions the parts are lowered by an active pressure in conduit 28 which, with the assistance of gravity, is sufiiclently high to force the parts down against the reduced pressure in the conduit 21. Due to resistance in conduit 21 to the outfiow of fluid, after the ,high pressure supply has been cut off and the passage has been opened to exhaust, and to the action of fiuid in passage 28 on the cylinder, the pressure in conduit 21 is still high enough to elevate the parts and would do so except for the greater pressure in conduit 28 tending to force the parts down. But if the pressure in conduit 21 fails this causes pressure in conduit 28 to fall below that necessary to hold valve 36 open and when this valve closes it traps fiuid in the upper end of the cylinder (check valve 3|] closing against any outfiow through passage 29) so that it is impossible for the parts to fall until the normal minimum pressure is again established in conduit 21. The low pressure or lack of pressure established in conduit 28, permltting valve 3B to close, prevents any appreciable tendency to force the parts down against the fluid trapped in the upper cylinder Chamber.

A simple device for providing this control is shown'in Fig. 8 where a piston 46 in a cylinder 41 is moved by high pressure in conduit 21a against a spring 48 to keep closed a relief line 49 from the low pressure conduit 28a. When pressure in conduit 21a fails, it opens the relief line 49, thus lowering the pressure in conduit 28a and permitting valve 36 to close to trap fluid in the upper end of the cylinder to prevent it from falling. f

While the invention is shown and described in connection with one cylinder and piston arrangement only, it is to be understood that it may be under for both cylinder and piston arrangements if necessary. It is to be understood also that the inventlon is applicable to any character of machine having a single or multiple cylinder carriage.

Various changes may be made in the detailed construction and arrangement'of the parts described without departing from the spirit and substance of the invention, the scope of which is defined by the appended claims.

What ls claimed is:

1. A fiuid operated device including a cylinder element and a piston element Operating in the cylinder to define two pressure chambers therewith and having a piston rod extending in sealed relation therefrom, one of said elements of the fluid Operating device being fixed and the other being movable, a first passageway in said piston rod opening into a first one of said cylinder chambers on one side of the piston, a second passageway in said piston rod opening into a second one of said cylinder chambers on the other side of the piston, a valve chamber in said piston rod, axially spaced passages opening from said valve chamber, one into said first passageway and the other into said first cylinder chamber, a third valve passage connecting one end of the valve chamber with said second passageway, a valve in said valve chamber, spring means urging said valve into position to close the connection between said first and second valve passages,

and said third valve passage entering the valve Chamber at one end of the valve to permit fiuid from the second passageway to move it against its spring to keep the first and second valve passages connected as long as sufficient pressure exits in said second passagewair and to close the connection when the pressure drops below that necessary to oppose the spring.

2. A fluid operated device including a cylinder element and a piston element Operating in the cylinder to d-efine two pressure chambers therewith, said fluid operated device having first and second fiuid passageways for conducting fluid to and from said chambers to effect elevating and lowering movement of one of said elements and means for maintaining a predetermined pressure on fluid being conducted from one chamber of the cylinder by the second of said passageways as a result of fluid being conducted to the other chamber of the cylinder by the first said passageway, two outlets from the first passageway to its cylinder Chamber, a check valve for a first one of said outlets for preventing return flow from the chamber to said first passageway, valve means for the second one of said outlets, spring means urging said valve means to a position to close said second Outlet, said valve means being responsive to fiuid pressure in said second passageway during elevating and lowering movements to open said second outlet and being responsive to drop in pressure below a predetermined limit necessary to oppose said spring to close said second outlet and trap fiuid in the chamber of the cylinder to prevent said lowering movement.

3. A fluid operated device including a cylinder element and a piston element Operating in the -cylinder to define two pressure chambers therewith and having a piston rod extending in sealed relation therefrom, one of said elements of the fiuid operated device b-eing fixed and the other being movable, a first passageway in said piston rod opening into a first one of said cylinder chambers on one side of the piston and a second passageway in said piston rod opening into the second one of said cylinder chambers on the other side of the piston, valve means for controlling the flow of fiuid from said first Chamber to said first passageway, and means responsive directly to pressure of fluid in said second passageway for keeping said valve means open, said last-mentioned means being responsive to a failure of pressure in said second passageway for closing said valve to trap fluid in said first chamber, the control system for the said first and second passageways including means for causing pressure in the second passageway to fall below the predetermined value necessary to keep said valve means open upon sufiicient failure of pressure in said first passageway.

4. A fluid operated device including a cylinder element and a piston element Operating in the cylinder to define two pressure chambers therewith, said fluid operated device having first and second fluid passageways for conducting fluid to and from said chambers to effect elevating and lowering movement of one of said elements, two outlets from the first passageway to its cylinder Chamber, a check Valve for a first one of said outlets for preventing return fiow from the chamber to said first passageway, valve means for the second one of said outlets, and means responsive directly to pressure of fluid in said second and through the pressure of fluid in said second passageway which is made dependent upon pressure of fiuid in said first passageway for lreeping said valve means open during operation except upon pressure failure in either the or second passageway.

5. A fluid operated device including a cylinder element and a piston element Operating in the cylinder to define two pressure chambers therewith and having a piston rod extending in sealed relation therefrom, one of said elements of the fiuid operated device being fixed and the other being movable, a first passageway opening into a first one of said cylinder chambers on one side of the piston and a second passageway opening into the second one'of said cylinder chambers on the other side of the piston, and control means, including a valve for ycontrolling the flow of fluid from said first Chamber to said first passageway, for closing said first passageway upon failure of pressure in either of said passageways, said control means including interacting means for causing pressure in said second passageway to drop and said valve to close upon failure of pressure in said first passageway.

HOWARD E. SOMES. BENJAMIN R. PURVIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNXTED STATES PATENTS Number Name Date 993,967 Debauche May 30, 1911 1,960,3'79 Havens May 29, 1934 2,027,706 Schauer Jan. 14, 1936 2,186,266 Onions Jan. 9, 1940 2,216,486 Cooke Oct. 1, 1940 2,328,979 Herman Sept. 7, 1943 2,363,196 Nye Nov. 21, 1944 FOREIGN PA'I'ENI'S Number Country Date 432,390 Great Britain July 25,` 1933