US2158355A

US2158355A - Piston expander

Info

Publication number: US2158355A
Application number: US70243A
Authority: US
Inventors: Claud C Craven
Original assignee: AB Chance Co
Current assignee: AB Chance Co
Priority date: 1936-03-23
Filing date: 1936-03-23
Publication date: 1939-05-16
Anticipated expiration: 1956-05-16

Description

May 16, 1939. c. c. CRAVEN PISTON EXPANDER Filed March 23, 1956 I INVENT ATTORNEYS.

- 25 Figure 1 is a front elevation of a piston expand- Patented May 16, 1939 PATENT mm PISTON EXPANDER.

Gland C. Craven, Kansas City, Mo., assignor to A. B. Chance (10.. a corporation Application March 23, 1936, Serlal'No. 70,243

2 Claims.

This invention relates to piston expanders and particularly to a piston skirt expander wherein a resilient member is adapted to exert pressure in opposite directions against the marginal walls of the split of a piston skirt.

' The principal object of this invention is the provision of unitary structure adapted to .engage and force apart the marginal edges of the slot formed in the skirt of a piston whereby said skirt is expanded. Another object of the invention is the provision of a resilient, U-shaped piston expander having a transversely disposed lug adjacent each of the free ends thereof formed to project into and se- 5 curely engage the marginal edges of a slot formed in the piston skirt.

Other objects of the invention are econoifiy and simplicity of construction, ease of installation, and the provision of means whereby the expander securely engages the skirt.

With these and other objects which will appear1 during the course ofthe specification in view, reference'will now be had to the drawing, wherein: I

or embodying this invention.

Fig. 2 is a side elevation of the same. Fig. 3 is an outside view of a portion of the skirt of a piston, showing the expander in the operative position.

Fig. 4 is a vertical section, taken on line IV-IV of Fig. 3. o

Fig. 5 is an inside elevation of a portion of the piston skirt, showing the expander in the oped ative position, and, Fig. 6 is a fragmentary,'cross sectional view taken on line VI-VI of Fig. 3.

Like reference characters designate similar parts throughout the several views, and the nu-" meral It) represents a portion of the skirt of a piston, provided with a slit or slot I2 that extends from the open end of the skirt to 'a point adjacent the sealing portion or head of the piston. The margins or side walls M of the -slit are provided with oppositely disposed receiving orifices l6 which are' substantially symmetrical at opposite sides of the slit. These orifices combine to produce a" substantially frusto-conical holethrough the skirt, with the larger crosssectional area at the outside thereof, thus forming inwardly converging side walls for reasons hereinaiterset forth.

Referring now particularly to the expander which is shown in its normal form in Figs. 1 and 5 2, it will be observedthat it comprises a single strip of resilient sheet metal ll which is rebent upon itself into a substantially U-shaped body portion 20, the arms 22 of which are slightly bowed inwardly as at 24. Extending in like direction and in transverse relation to 20, adjacent 5 the free end of each of the arms 22, is 9. lug 28. Each lug is substantially semi-circular in cross section and semi-frusto-conical in a plane'perpendicular to arm 22.

With reference to Figs. 3, 4, 5 and 6, in which 10 the expander is shownin the operative ,position in the piston Skiltyit will be noted that these lugs 26 are adapted to be fitted into orifice l6 so as to conform to the inner walls thereof insuch a manner as to preclude any accidental removal of 15 the expander from its operative position. When ,.the expander is to be positioned in the opening formed throughthe skirt, the arms 22 are compressed' sufllciehtly to allow the lugs to. be, introduced from the inside of the piston through 20 the small side of the opening, after which they are permitted to be 'forced outwardly against the side walls by the action of the tension set up -in.the body of the expander. When so positioned, 'points 2i of the two arms will be-in contact, 25

thereby shortening the fulcrum lever of lugs 26 to produce a much greater pressure against the opposite walls of slit 12 than could be obtained 'with the fulcrum at the closed end of the U- shaped body portion. I x 3 As a further means to facilitate proper tensioning of the lugs for expanding the piston skirt,

arms 22 are tapered from their greatest width at the closed end of body 20 to their'narrowest width at their free end.- That portion 28 at the 35 free end of each of the-armswhich extends beyond lugs 26 serves to contact the innerwall of the piston skirt to prevent undesirable rocking of the body portion. i

The undercut relation of the lugs and the side 6 walls of the conical hole in the skirt of the piston is such that it becomes necessary to compress the outer ends of arms 22. to a considerable degree before the expander can be released from its operative position. This feature is veryimpor-- 45 tent and insures the proper relation of parts without danger of the expander becoming dislodged to cause interference with the proper action of the piston within the cylinder.

While I have shown the arms contacting at 2'4 50 in the drawing, it would be possible to so construct the resilient portion of the expander so as to produce the exact tensions necessary to obtain proper expansion under all circumstances.

Having thus described theinvention, what I 5 v claim as new and desire to secure by Letters Patent is:

' 1. In combination; a piston comprising a head portion and a skirt having a longitudinal slot therein forming opposed edge faces, each of said faces having a notch therein extending transversely of said longitudinal slot, said notches being in opposed relation and combining to create a frusto-conical orifice through the skirt of the piston with its largest diameter at the outer face of the skirt; and a sheet metal expander comprising a resilient U-shaped body adapted to exert expanding force against the opposed edge faces of the skirt, said body having a laterally extending lug on one edge of said body adjacent to each free end thereof the remote faces of said lugs combining to present a irusto-conical surface engageable with the said orifice of like form when the expander is in the operative position.

2. In combination; a piston comprising a head portion and a smrt having a longitudinal slot areas therein forming opposed edge faces, each of said faces having a notch therein extending transversely of said longitudinal slot, said notches being in opposed relation andcombining to create a frusto-conical orifice through the skirt of the piston with its largest diameter at the outer face of the skirt; and a sheet metal expander comprising a resilient U-shaped body adapted to exert expanding force against the opposed edge faces of the skirt, said bodyhaving a laterally extending lug on one edge of said body adjacent to each free end thereof, the remote faces of said lugs combining to present a frusto-conical surface engageable with the said orifice of like form when the expander is in the operative position, said lugs being in opposed relation and spaced inwardly from the free ends of said U-shaped body whereby to prevent rocking movement of the body toward and from the skirt of the piston.

CLATUD C. CRAVEN.