US2665774A - Piston lubricating means - Google Patents

Description

Jam 12, 1954 E. w. PATTERSON 2,665,774

PIsToN LUBRICATING MEANSv Filed June 27. 1949 lNVENToR.

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l-latented ian.

PISTON LUBRICATING MEANS Edgar W. Patterson, Downey, Calif.

Application June 27, 1949, Serial No. 101,619

(Cl. 18d- 18) 8 Claims.

This invention relates to pistons within cylinders and means for eiectively lubricating and sealing pistons with reference to the cylinder bore, and particularly pertains to piston lubrieating means.

This invention is specically adapted and is of great importance in connection with airbalanced oil well pumping units of the general type as that shown in my recent Patent No. 2,464,710, issued March 15, 1949, and in various other types of air cylinders.

In all arrangements whereby the cylinder is iitted with a partial head or cover at the lower end theerof, there must consequently be a con* tinuous displacement of air both into and out of `the lower or atmospheric pressure end of the cylinder. This condition holds true as regards the above mentioned patent and all similar arrangements. The continuous taking in of new air at each stroke of the cylinder will, under certain operating conditions, give trouble and cause unnecessary wear on the piston, rings, and cylinder walls, when the machine is operating in the open oil fields where there is considerable dust and sand present in the atmosphere. As a matter of fact the oil contained in the annulus acts as a trap for dust entering the chamber, and consequently there is a continuous accumulating of dust and foreign matter within the oil supply reservoir at all times. It is therefore the principal object of the present invention to provide a cylinder, piston, and means for lubricating same, wherein there will be no displacement of air below the piston within the cylinder, and to provide an oil reservoir that is not subject to contamination from the atmosphere.

Other objects and advantages` of the invention will be apparent from the following description and claims, the novelty consisting of the features of construction, combination of parts,

the unique relations of the members and the rela.. tive proportioning, disposition, and operation thereof, all more completely outlined herein and particularly pointed out in the appended claims.

The invention is illustrated by way of example in the accompanying drawing in which:

Figure 1 is a View in side elevation, with prime mover broken away, of an air-balanced pumping unit embodying the present invention.

Fig. 2 is an enlarged axial vertical View in elevation taken along the line 2-2 of Fig. 1.

Fig. 3 is a transverse sectional view through the cylinder and piston taken in the plane of line 3-3 of Fig. 2.

Fig. 4 is an enlarged vertical sectional View through the oil pump taken along line 4--4 of Fig. 2.

Fig. 5 is a transverse sectional view as seen on the line 5-5 of Fig. 4.

Fig. 6 is an enlarged fragmentary sectional View in detail of one side of the lower part of the piston as shown in Fig. 2, showing more clearly the oil scraper rings.

As seen particularly in Fig. 1, there is provided a pumping unit supported jointly by a generally horizontal base Ill, and an identical pair of vertically positioned parallel members Il dis posed at opposite sides thereof. The individual members I I are joined together by suitable bracing to form what is known as a Samson post, which is maintained in its vertical position by means of a pair of `angular struts or braces l2. These braces have their ends secured respectively near the top of the upright members II and adjacent to the horizontal base Ii), and are aixed at the latter point to a geared set back crank mechanism I3. The lower end of the Samson post II is in turn attached to the main base II) by suitable hinge pins I4.

The conventional walking beam I5 is pivotally` secured at one end to the top` of the Samson` post II by means of a shaft I6 and carries at its`v opposite end a horse-head Il over which the:

reins It! attached to a pump rod will operate.

An air receiver or tank I8 is located adjacent;

the Samson post upon the main base I0. Ro

tatably journaled in a conventional gear unit 29 is; a low speed main drive shaft 2|, to each end of.' which is fixed a crank 22, one at each side of the'- gear unit. The shaft 2| is suitably connected to a` lpower unit by suitable conventional driving:

means not shown in detail.

A cylindrical air-balance cylinder 23 is pivotally supported at its top by a universal mounting from a cross-head assembly 24 axed to the under side of the walking beam I5, the balance cylinder being thus adapted to reciprocate vertically over a stationary piston 25 supported within the cylinder 23 by means of a vertically disposed tubular piston rod member 2S, which in turn is pivotally mounted at its lower end in bearings 2'! carried upon the base I0. The upper end of the hollow piston rod 26 communicates with the compression space 28 above the piston 25 within the cylinder 23, and the lower end of the hollow piston rod 26 communicates with the air receiver I 9 through the pivotal base 29 and the air duct 30.

A pair of vvertically swinging pitman rods 3| are `pivota'lly secured to cross-head member 24 `way. of pressure line 49. '.IVhere'isganannul g grepen spaceg inlinedlately,belovi` the z upper partei piston 25 andabove'ihe retrait .there- ..of. :This gap orannulus willpermitairnnder f bracket wafforzthe Quin Y the stroke length-pf: the .-Ql .puma 39. ,as @result oil from the wall,oirthegcylmdergz l it vto enter reservoirea by@,m e; 1s oslmalble` "sraperrines :141 and: drainage rents 56 Keem-lv` inunioatingv withgside L:Wall vents; lgleadingpto freservoir138- at their upper ends, and are attached by a journaled crank pin 32 to the crank arms 22 at their lower ends.

Fxedly secured to the piston tube 26 is a suitable mounting bracket 34 upon which is mounted the piston rod 35 of an air compressor 36, which in turn is attached to the main cylinder head 33 and adapted to reciprocate simultaneously with the main balance cylinder for use as a source of supply for: compressedrair duringy normal operation of the pumping` unit.

As here illustrated, the main piston 25 is mounted upon the upper end of the hollow piston rod 26, and consists generallyora cylindrical casting, or fabricated member which'is divided into an upper reservoir Shandfuaylolllr reservoir 38. The upper reservqirlis Ytheil retaining reservoir which is supplied with -oil at regular intervals by means of an oil rpurnp`39 supported upon bracketxAO affixed to piston tube 26. Theoil carried vinreservoir 31 isadapted to l'ubricate and seal the piston 25 within the cyl- .der 2,3.by meansbf .drilled holesilt throughfthe circumferential walls 42,91?-therpiston.25 lead ing lto.y van annular, grooves. 43 .therearound. The

lower reservoir f 38 Of the piston 251s adapted Uto. ,traps any oil thatmay., bypass. the upper part,

or compression partjo'f'piston. ,Thefupper g piston ringsl or packing. rings...4r4 for `.vvitltiblrlingv4 air p `or oil vunder pressure.,abovethepstonl. V.The lower partofthe piston- 25.`i s`f,proylded .witha y circumferential sidwall 45 Y having.. grooves ,4,6

into whichvare ttedpistoniings ,A1.,thatare adaptedpto scrape oiliromfthecylinder wa11. 23

pump .31,by

39. and .thence returned to` upper reservo pressure that mayrbypass thefconiprwss'ion.ring

and esepe t0- the rfatmosphere by lmeans.-.f-.vent

tube :511. through ibex-lower headtoifpiston .2,5. Y Therefis amanuallvadiustable sontactmembei. warranted tol iheouteracrlineer van brine Qi rredeterminine L er any.y change beineamadeas :reeardsthe pumpvling strokeoi the puinpineunitl The-.Q11 Pump. `.as illustrated .in Fie-z: i,` is 0f .the simple :piston displacement type emr 1oyr-1g.V 'van iaintakespring 55 adapted to.returrrthenistonfffstoits uppermost position. 1t is to be understood how- `ever,v that any.. type; pump. located at; arly-S .liable place about the pumping unit marche giegtively, employed Without. departingn the; teachings ..herein.

Fig. 6 vshows in detail one: method forscranins 11d causing @In order toKV establish theglevel.oi the accubular shaft 26 and isheld permanently ata:y delubricating and sealing method is predicated upon the assumption that any oil that has been placed in reservoir 31 that may bypass the upper part of piston 25 will be entrapped in the 5 lower reservoir 38, from which it will be directed to a pump 39 and thence returned under pres sure to reservoir 31 from where it came without any appreciable escapement olf oil externally of the system, or contamination from the atmos- .phera Y In operation ofthe present invventilonvit will be understood that the cylinder 23 is held to the across-head 24 by some suitable pivotal means, ``such foi-errarnple as a bolt receiving bore 60 'formedin ear means mounted on the closed end kgi-cylinderzg The -cylinder 23 can oscillate as yit reciprocates upon the oscillating piston 25. lThe reservoir -31Lbf the piston 25 may then be filled-Eto va desired level with lubricating oil, and the limit of this level may be determined by adjustingy the, tube 58. `As the pump operates the Ypist'ofn 25v will' relciprocatewthin the cylinder 2k3 endet that time lubricating *oil'fvvilly pass vout through, the: ductsA 4 I *and* the vanrnllar Y groove 43 to lubricate the cylinder. The piston' ringer lwill tend tok prevent leakage of lubricating bil. If, however, lubricating oil s houldfrnove p ast the Vpiston ringsiit will iiqwiinto the reservoiry 38. Attention .isdirected to the vfavcthtl'iatfthe"'res'ei 3o Ivoir 38 isl atatrno'spheric pressures() vthat the lubricating oil will bev reeto flow 'downwardly talong ,the walls of the cylinder.` YThe members ,41 in the reservoir,33',will.tendtol s crapeoff the nexcess oil and divert it inwardly'throughthe ducts 56 to thereservoir 3S,` '.Anyexcessof vthis oil will :be drawn throughvthe pipe vtolfthe valve filbithepump structure, `and as the cylinder I23 movesdownwardly the member 52 will 'strike the'piston rod head1h35 and. force oiloutwardly c ,through Ythe'*discl'iarge lvalvejflto theY pipe"49. -The lubricating' oil will ,then'dldw upwardlyin the pipe `A49,through.the reservoirs 3 8 and 31 and will @be discharged f into v the x reservoir' 31, 'thus .Qmpletlg thff'yleg 45 .It Vwill` thus bey seen .thatby lizhisirneansit. is fr,possible .to automatically 'replenish Vthe j lllblcatging oil.on the pstonifandcause itto fcir'culate she-'pump functions? c, vVifhile' IQhave shown .the preferredorm .of my invention asnow known tome, it `wllbefunder- .stood that vari'ous'chan'g'esinaybe made in ,com-

bination, construction and 'arrangement,y of parts by ,thoseslrilledin theartQwithout departing `irointl'ie spirit.L of. the invention .asV clairneol.v l ,Having thus aescnbedmy; .,irivejnti, ngwhat, I claim and desireto secure K`by 'Letters Patentv is: 1.7.-,In an airdbalance 4for aiwellipumpingunit having `a:basefavnd a walling beam mounted thereon for vertical. `Ym.vement .and from, which `asuclzer vvredis suspended in the ywellfthe combirra-tiony of amcylinder, s oneend .of *whichd is closed andthe other end of which is open, said c gvlinderallarme means for, eivoially Connetiing vit Vclosed end to said. beam, with` itsother'hend opening downwardly; Y a piston Vvslideable in said cylinderv and forming a reseryoirior` oil, there beingupassagemeansfor Ioil'to flow furomsaid .reservoir tothe Ameeting faces oi'saidpiston and said cylinder Ato -lubricate said -faces "a piston Y 0roduunited with said piston, said`rod extending downwardly `out of said cylinder.r and having means for. pivotallylmounting Saidfrod on fsaid basey'means for admittingair underl high pressure to the interior of `said cylinder abovejfsaid acaban the pressure of said air; an oil collector carried on said rod below said piston and tting said cylinder walls closely to scrape from the latter oil escaping downward past said piston when said cylinder reciprocates with respect to said piston and said collector; a pump mounted on a lower portion of said piston rod; an actuator carried by said cylinder and engaging said pump to actuate the same; a suction line connecting said oil collector with the suction side of said pump, and a discharge line leading from the discharge side of said pump and opening into said oil reservoir, whereby actuation of said pump will withdraw oil from said oil collector and discharge the same into said oil reservoir.

2. A combination as in claim 1 in which said oil collector makes a substantially airtight engagement with said cylinder wall; and an air bleeder tube communicating between the space between said piston and said oil collector and the air at atmospheric pressure below said collector.

3. A combination as in claim 1 in which said oil collector comprises a secondary piston providing an oil collecting basin therein and having oil scraping piston rings, said secondary piston being provided with passageways leading from said piston rings to said basin.

4. In an air balance, the combination of a cylinder, one end of which is closed and the other end of which is open; a piston rod; a piston on said piston rod and adapted to slide within said cylinder with the latter in upright position with its open end disposed downwardly, said air balance being adapted to operate with said cylinder and piston thus disposed so as to result in sliding reciprocatory vertical relative movement between said cylinder and said piston; means for admitting air under high pressure to the interior of said cylinder above said piston, said piston forming a reservoir for oil, the latter being subjected to the pressure of said air in said cylinder, there being passage means through which oil may ow from said reservoir to the space between said piston and said cylinder, a certain portion of said oil escaping downwardly from between said piston and said cylinder incidental to said reciprocation and said air pressure; an oil collector carried on said rod below said piston and fitting said cylinder closely to scrape from the latter said escaping oil, said collector providing a basin in which said oil collects and pump means for returning said escaped oil from said collector basin to said piston reservoir.

5. A combination as in claim 4 in which said collector has a substantially air tight sliding t with said said cylinder, there being a bleeder passage in said collector communicating between the space between said piston and said collector and the space below said collector.

6. A combination as in claim 4 in which said oil pump is disposed outside said cylinder and is actuated in response to the aforesaid relative vertical movement between said cylinder and said piston.

7. In combination: a cylinder one end of which is closed; a piston rod; a piston on said piston rod closely fitting and slideable reciprocably within said cylinder against a uid pressure head in said closed end of said cylinder; means in said piston for supplying a lubricant to the space between said piston and said cylinder, certain portions of said lubricant thus supplied leaking past said piston due to the fluid pressure head against which said piston operates; oil recovery means mounted on said piston in spaced relation with the end of said piston from which said lubricantI leakage occurs, for recovering from the walls of said cylinder the excess of lubricant leaking past said piston; and means for returning said recovered lubricant to said lubricant supply means in said piston.

8. A combination as in claim '7 in which said lubricant recovery means closely ts said cylinder to scrape said lubricant from said cylinder in recovering the same; and means providing for the escape of fluid from the space between said piston and said lubricant recovery means to maintain a fluid pressure in said space which is not substantially higher than the iiuid pressure in said cylinder on the opposite side of said lubricant recovery means from said space.

EDGAR W. PATTERSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 414,777 Morison Nov. 12, 1889 445,110 Graham Jan. 20, 1891 2,035,450 Barnes Mar. 31, 1936

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