US1820228A - Pump piston - Google Patents

Description

Aug. 25, E. KlBELE PUMP PISTON Filed D80. 11. 1928 v dttozuu;

5 woe; m 3 f Patented Aug. 25, 1931 UNITED STATES PATENT OFFICE ll'U'G-ENIEI KIBELE, OF SAN ANTONIO, TEXAS; EUGENIA SCHROEDER, EXEGUTBIX OF 0 SAID EUGENE KIBELE, DECEASED rum? nsron Application filed December 11, 1928. Serial No. 325,298.

It is also an object of my invention to arrange a piston in such a manner that each of the parts may be readily replaced, but will at the same time present a rigid piston capable of prolonged service.

Another object of my invention is to arrange the piston ring upon the hub and having a stabilizer member to firmly support the piston ring.

Another object is to so construct the portions of the piston that a minimum of material will be used as compared with the service which the piston will render.

Still another object is to construct the head of the piston body with a plurality of serrations to contact the piston ring in such a manner that the ring will be mechanically expanded to contact with the cylinder wall.

Other and further objects of my invention will be readily apparent to those skilled in the art to which my invention appertains when the following description is considered in connection with the drawings, wherein:

Fig. 1 is a central vertical section of one gr form of my improved piston showing the several parts clamped on the piston rod in operative position in the pump cylinder.

Fig. 2 is a View similar to Fig. 1 but showing a slightly modified form which the invention may assume.

Fig. 3 is a detailed view of a follower member in position in the piston ring and showing the form which the serrations may take.

Fi 4 is a sectional view in reduced size showing the shape of the packing rings as they are free of the piston.

By having reference toFig. 1 'the pump cylinder or liner has'been indicated by the numeral 1. The usual pump rod or piston rod is shown at 2 and is slightly tapered to receive the piston body 3 which serves to retain the piston ring indicated generally at 4. The piston body 3 comprisesa body portion or hub 6 and a cross head 5 which is formed with an annular flange 7. The head 5 has a central bevel 8 about the rod2 and has a face 9 which is perpendicular to the path of movement of the rod 2. The periphery of the head 5 is inclined toward the end of the rod 2 to form an edge indicated at '10 and mesh with the rim 13 of the inner side of the head 5.

This rim is spaced somewhat from the sleeve 6 so that a groove 12 is formed for a purpose which will be later described.

The body 6 has considerable length and extends almost to the end of the rod 2 and is adapted to receive the follower member 18 which is in the form of a cap member which fits over the rod 2 and has a flange which overlies the end of the body 6. This flange is similar in contour to the head 5 and has a perpendicular face 20, a peripheral edge 21, a rim 23 and a groove 22 which are similar to the corresponding parts of the head 5. The nut 19 is threaded onto the rod 2 and serves as a means of clamping the hub and follower member together against the packing ring.

The piston ring in this modification is shown as composed of two annular sections, such as 25. Each of these sections has an inner circular face 31 which slides closely onto the body 6. Perpendicular to this face 31 is a lip 27 which is adapted to seat in the oove 12 or 22. An indentation 28 merges with the lip 27 and receives the rims 13 or 23. From the indentation 28 the ring curves outwardly and is flared to contact the periphery 10 of the head and terminates in a skirt portion 29. The outer surface 30 of the rin when in position in the cylinder is approximately concentric with the inner surface 31. The free shape of the outer surface is slightly concave from end-to end with the central portion smaller than the bore of the cylinder. The skirt 25 is made with a slightly larger diameter than the bore of the cylinder in order that there may be some initial pressure exerted against the walls of the 10 cylinder. This increased diameter of the skirt does not prevent easy assembly. The action of the compressible material in the ring under both mechanical and hydraulic tension is described later. 'This surface 30 is adapted to contact the cylinder wall as shown in the drawings. Each of the ring members has on the side opposite the indentation 28 an annular cut out portion 33 hav ing a face 32 which leaves a ridge 34 on the outer surface 30. The two cavities 33 when the piston is assembled form an annular space adapted to receive a stablizer member 35.

' This member is in the form of a ring or disc which slides onto the sleeve member 6 and is preferably tapered inwardly so that the widest portion is at its periphery.

The piston of my invention is adapted for use in what is known as a double acting pump in that a working stroke is accomplished in each direction of the piston- Due to the type of operation the piston is subjected to a hydraulic pressure on the working stroke which tends to force the skirt 29 against the cylinder 1, forming a seal and-preventing the passage of fluid, but on the return stroke it is subjected to suction in drawing the charge into the cylinder, and this suction tends to drafiv the skirt 29 away from the cylinder wa In constructing this piston, so that it may best serve the function required, the lip and groove arrangement of the hub and ring serves to firmly clamp the face 31 against the body 6. As the rims 13 and 23 seat in the grooves of the ring'and the inclined faces 10 and 21 contact with the skirt 29 axial pressure is exerted upon the ring. Axial pressure tends to compress the inner portion ofv ring 25 and hold it firmly in place between rims 13 and 23 and the stabilizer member 35 and proximate points 43 and 44. The amount of said expansion is according to precalculated limits and is such that the diameter of the ring between these points is increased to the desired running size after the piston is; assembled in the cylinder. This axially applied pressure, together with the radial resultant of the hydraulic pressure exerted on skirt 29 creates a radially directed movement of the resilient material whichv acts as a seal on cylinder 1 against any hydraulic force With the above'construction it will be readily apparent that I may manufacture the piston rings of substantially the same or smaller in size than the cylinder in which they are to operate so that they may be readily inserted in the cylinder. The follower plate 18 and nut 19 are then placed in position and as the nut 19 is tightened the clamping action distorts the piston ring expanding it radially so that a firm and positive seal is obtained with the cylinder wall. I therefore rely upon the inherent resiliency of the piston ring material to obtain the fluid seal of the piston.

In Fig. 3 I have shown the follower plate as formed with a plurality of serrations 15 on the periphery 21. These serrations are of greatest depth at the outer face and gradually merge with the periphery 21 as the rim 23 is reached. The inner surface of the piston ring at 16 is preferably smooth and as the follower plate is drawn up a portion 17 is forced into each one of the serrations. In this manner small particles of grit and sand are prevented from entering between the metal and the piston ring. These serrations also aid in distorting the piston ring in the clamping actioneffected. Due to resilient material used in rings 25 and the more pliable construction embodied in the skirt 29, it is obvious that it is entirely practical to run this piston in a cylinder, the walls' of which are not parallel to the axis of the piston rod which condition may and does exist.

It is to be understood that the piston body, hub and follower plate as well as the stabilizer member are made of metal, but the piston ring may be made of any suitable resilient composition such as rubber..

The piston shown in Fig. 2 is similar in its action in so far as the piston ring and head are concerned, is identical with the disclosure in Fig. 1. The body sleeve 6 of Fig. 1, however, has been somewhat shortened and -is indicated at 6. The follower member 41 has been formed with a short sleeve 40 which is similar to the sleeve 6. The sleeves 6' and 40 combined are not equal to the width of the piston, but are adapted to receive between them the stabilizer plate 35 which is similar to the stabilizer plate in Fig. 1 except that the central opening therein is only of such size as to slide upon the piston rod 2. The sleeve 40 has a cut out cavity 42 so that it will not bind upon the rod '2.

Ill

With the construction of this embodiment v the stabilizer plate 35 is firmly clamped between the head and the follower plate so that each of the piston rings 25 is individually distorted so that the wear on each one will not be compensated for by a movement or yielding of the other ring such as is possible in the embodiment of Fig. 1.

It is to be understood that the serrations 15 can be made on either the head or the follower plate or either of the embodiments which I have shown.

While I have described two embodiments which my improved piston may assume, I do not desire to be limited to the exact contour shown except as specifically stated by the claims herein.

Having described my invention what I desire to secure by Letters Patent is:

1. A pump piston including an approximately cylindrical body, a radial flange at one end and a follower plate at'the other end, means to clamp said follower plate slidably upon said body, the peripheral surfaces of said flange and plate being tapered inwardly, a packing ring on said body between said flange and plate, and lips on said packing ring curved outwardly to overlie said flange and plate and tobe compressed outwardly thereby to force said lips more positively against the cylinder. I

2. A pump piston including an approximately cylindrical body,- a radial flange at one end and a follower plate at the other end,

means to clamp said follower plate slidably upon said body, the peripheral surfaces of said flange and plate being tapered inwardly, a packing ring on said body between said flange and plate, and lips on said packing ring curved outwardly to overlie said flange and plate and to be compressed outwardly thereby to force said lips more positively against the cylinder, said packing ring being transversely divided and a stabilizer plate midway of the length thereof.

3. A pump piston including an approximately cylindrical body, a radial flange at one end and a follower plate at the other end, means to clamp said follower plate slidably upon said body, the peripheral surfaces of said flange and plate being tapered inwardly, a packing ring on said body between said flange and plate, and lips on said packing ring curved outwardly to overlie said flange and plate and to be compressed outwardly thereby to force said lips more positively against the cylinder, said follo wer plate being serrated on its outer edge for the purpose described.

In testimony signature this 1928.

whereof I hereunto aflix my 7th day of December A. D.

EUGENE KIBELE.

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