US1773402A - Expansible piston - Google Patents

Description

Aug. 19, 1930. E. E. MILLER EXPANSIBLE PISTON Filed Ma 10, 1926 We Z'O77 Miller.

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Patented Aug. 19, 1930 PATENT ".oFri-cE.

nnwm n. MILLER, or rnLnnn ro i, cnnironnia EXPANSIBLE PISTON Application filed May 10, 1926.' Seriail No; 107,994;

This invention relates to improvements in pumps, and particularly to pistons having I e rpansiblepackings used therein. The invention may be considered as an improvement over that disclosed in the United States patent issued to Villiam F. McMahon, No. 1,474,201, datedllovember 13, 1923.

An object of this invention is to provide an improved plunger of novel construction 10, and'empl oying a novel means andmethod for expandingthe'packing. i

Anothenobject ofthis invention is to provide animproved plunger or piston which is so constructed that leakage between the heads is eifectively preventedf vide a packing of novel construction primarily designed to facilitate the assembling of pa rts forming the improved plunger.

A still further object of this invention is to provide an improvedplunger which may be I quickly adj usted and which can be very easily and cheaply constructed. v

, VVith the foregoing and other objects in view which will be made manifest in the following detailed description and specifically pointed out in the appended claims,- reference is had to the accompanying drawings for an illustrative embodiment of the invention, 3. wh ei 2 Figure 1 is a section view illustrating the improved plunger as disposed Within its cylinder orbarrehj Fig. 2 is a vertical section taken on the line Fig. Biis a side elevation of the. forward head'or' the head which is'mounted on the.

sleeve, o I V ,Figge is a front elevation of thesame I 91: Fig. 5' is a side elevation of therear head,

I Fig} (iiis airear elevationjof theLsame, I

."FigL'? isga vertical sectionthroiigh theim barrel of e pump is'indicated-at 10, an the plunger rod coupling or cross headjwhich acfurtherob'ectof this invention to pro Referring to th e accompanying drawings wherein-sim ar refe enc a a ters. ga ate lII fil1- throug o hecyh or improved plunger consists of a plunger rod 12having oneend threaded asindicated at 13 into the plunger rod coupling 11, so that the plunger rod is rigidly secured-to the coupling and held against rotation relatively thereto. About the plunger rod 12 there is" tormed thereon, which fit between and interlock with similarvprojections or fingers 18 formed on asecond head 19. The end of the plunger rod 12 remote from the couplingfll is threadedyas indicated .at 20,and is reduced to form a pin; 21'.

A threaded sleeve22is screwed onto this endof the plunger rod 12 and is tightened, in place. It is preferably locked from loosening by means ofa'cotter pin orthe like which can bedrivenfthrough the aperture 23, the cotter-pin fitting in grooves or recesses in the ends ofthe sleeve, which end is preferably hexagonal in form to facilitatetheapplicationtofra wrench to tighten it onto thev plunger rod 12..;Th1e head 19 has a closed hub which enclosesthe end of the sleeve 22. The threadsifformed on the exterior surfacev of the sleeve 22 arepreferably coarse threads of a relatively steep pitchfand' the end of the sleeve which is. most adjacent thehead l6 .is beveled ofi", forminga beveled shoulder constituting an, abutment againstwhich portions of the headlfi a nd the endoithe sleeve. may} abut; on. tightening the. jam nut 15 againstthegcouplingill. "Thetwoj heads 16 1 here is "disposed an'xptnsitiqg packing. 25;

which may. be fornied o f an an iular luring of l-,-' 1 er; "an a"mandate;e imi a ini i d their;QIQ11;the inside surpacking re r ai se riQ':

jections 2e. -"whie i;ai-;in "staggered: relation.

the fact that the interlocking or interfitting projections 17 and 18 prevent relative rotational movement between the heads. Consequently, as the head 19 is rotated, it screws up on the sleeve 22, moving toward the head 16 with the fingers 18 merely sliding between the fingers 17. Consequently, the two heads will be forced toward each other and the packing 25 will be forced outwardly. After the adjustment has been made, the jam nut 15 is tightened against the coupling 11, forcing the head 16 and the end of the sleeve 14 into engagement with the beveled end of the sleeve 22. j

The advantages of this construction are as follows When the piston is working under ordinary conditions, there is no extra apparatus being carried by it to be reciprocated, suchas is present in the McMahon patent above referred to. Furthermore, by the use of the sleeve 22, which is applied to the piston rod, the threads capable of being used can be much larger, affording a greater bearing surface on the head 19 and may also be of a greater pitch. In addition to this, the tight fit which occurs between the end of the sleeve 22 and the sleeve 14 and the head 16 prevents any-escape of. fluid which might enter between the heads and the packing 25. It will be understood that if fluid should escape between the heads and enter within the sleeve.

14 about the piston rod, itis very apt to squirt out between the collar 11 and the jam nut 15,

which is undesirable. The leakage which mightoccur between the sleeve 22 and the head 19' is effectively stopped, and such leakage which does occur is only limited to that quantity which is necessary to fill the closed hub 24. V

This is an important, feature of this invention for the reason that pistons of this type are frequently used in mud pumps, pumping fluids containing grit, sand'and the like, As the fluid is-p'umped under a high pressure, the sand orgritin the fluid, which leaks, very quickly cuts away the metallic parts about the crevice or opening through which the leakage occurs.

Tl e purpose of providing the projections 26 on the interior surface of the packing 25 is as follows; Wl en the piston is assembled in the pump cylinder, the head 19' is the last part to be applied. This is applied upon the sleeve 22. and isxrotated by applying a wrench or the like to the hexagonal portion of the end of the hub 24. In screwing this head upon the sleeve 22 the end faces of the fingers 18 might abut the end faces of the fingers 17, so that the fingers 18 will not enter between the fingers 17, but will merely rotate the head 16 and the sleeve 14. By the use of the proj e'ctions 26, which are projecting very slightly, one set of projections is caused to fit between the fingers 17 so that rotation of the packing 25 relatively to the head 16, while the head 19 is being applied, is effectively stopped. On screwing up the head 19, if the ends of the fingers 18 should encounter the side facesof the projections 26, the head 19 can be rotated, causing the fingers 18 to ride over these projections and fit against the interior surface of the packing 25 between them. In this way the packing 25 will become locked to some extent against rotation relatively to the head 19, and as it is also effectively locked against rotation relatively to the head 16, the head 16 will be caused to rotate with the head 19 while the head 19 is being screwed up, and in this manner the fingers 18 will be maintained in that position in which they can enter between the fingers 17 on the application of the head 19.

From the above described construction it will be readily appreciated that the improved plunger is of simple construction and operation during adjustment. Furthermore, leakage between the heads, which is quite disadvantageous, is effectively prevented by means of the closed hub or cap 24 and the ti 'ht fit established between the sleeve 22 and the head 16 and sleeve 14.

It will be understood that various changes in the detail of construction may be made without departing from the spirit or scope of the invention as defined by the appended claims.

I claim:

1. In a pump, a plunger rod held against rotation upon the plunger rod coupling, a sleeve disposed about the plunger rod, a head mounted upon the sleeve, a threaded sleeve mounted upon the end of the plunger rod, a second head threaded onto the second sleeve, means for holding said heads against relative rotation, and an expansible packing disposed between the heads whereby upon rotation of the first sleeve, said heads may be rotated thereby, causing the second head to move relatively to the first head and thus expand the packing. I

2. In a pump having a plunger rod coupling, a plunger rod secured against rotation relatively thereto, a sleeve disposed about the plunger rod having one end bearing against the plun er rod coupling, a jam nutthrea-ded onto the mentioned end of the sleeve, a head rigidly mounted upon the other end of the sleeve, a threaded sleeve mounted upon the end of the plunger rod, a second head threaded onto the thlfiaded Sleeve, means for holding the heads against relative rotation, a packing disposed between the heads adapted to be expanded upon rotation of the first;

sleeve, causing the heads to be rotated and causing the second head to move toward the first head upon rotation of the first sleeve, said threaded sleeve providing an abutment against which the end of the first sleeve is adapted to abut on tightening the jam nut against the plunger rod coupling.

3. A pump plunger comprising a plunger rod, a sleeve disposed about the plunger rod, a head mounted upon the sleeve, a threaded sleeve mounted upon the plunger rod, a second head threaded Onto the -threaded sleeve, means for locking said heads against relative rotation, and a packing disposed between the heads, said threaded sleeve providing an abutment against which the first sleeve abuts.

4. An eXpansible packing adapted to be used uponplungers of the class described comprising an annular packing body having staggered projections on its interior surface to be used as and for the purpose described.

5. A pump plunger comprising a piston rod, a sleeve disposed about the piston rod, a head secured to the sleeve, a second head threadedly mounted upon the plunger rod having a closed hub enclosing the end of the plunger rod, means for locking sald heads against relative rotation, and means providing abutments upon the plunger rod adapted to limit endwise movement of the first head and sleeve whereby upon rotation of the first, head and sleeve, the second head may be adjusted toward or away from the first head,

said abutments beingadapted to form a liquid tight seal in limiting the movement of i the first head and sleeve to prevent leakage of fluid from between the heads through the first head about the plunger rod.

In testimony whereof I have signed my name to this specification.

ERWIN E. MILLER.

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