US1329823A - Composite piston for internal-combustion motors - Google Patents

Description

F. A. PARKHURST.

COMPOSITE PISTON FOR INTERNAL COMBUSTION MOTORS.

APPLICATION FILED JULY 24,1916- RENEWED OCT. 24,19IB.

Patented Feb. 1920.

3 SHEETS-SHEET 1- llll I 1', j 'r L w 4% Patented Feb. 3,1920.

3 SHEETSSHEET 2.

F. A. PARKHURST.

COMPOSITE PISTON FOR INTERNAL COMBUSTION MOTORS.

APPLICATION FILED JULY 24,1916. RENEWED OCT! 24,1918.

Patented Feb. 3, 1920.

3 SHEETS-SHEET 3- imp STATES PATENT OFFICE.

. 2 FREDERIG A. PARKHURST, 0F CLEVELAND, OHIO, ASSIGNOR TO THE ALUMINUM CASTINGS COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

COMPOSITE PISTON FOR INTERNAL-COMBUSTION MOTORS.

Specification of Letters Patent.

Patented Feb. 3, 1920.

Application filed .Tu1y 24, 1916,-Seria1 No. 110,845. Renewed October 24, 1918. Serial No. 259,596.

To all whom it may concern: Be it known that I, Fnnonnro A. PARK- HUnsT, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in and Relating to Composite Pistons for Internal- Combustion Motors, of which the following is a specification.

This invention relates to pistons for use particularly in internal combustion motors. One. of the objects of my invention is to produce a simple, light, durable and efiicient skirted, composite piston peculiarly adapted to meet the conditions which exist within an internal combustion motor cylinder, including the stresses and strains imposed upon the piston, principally during the explosion stroke and by the high heat generated at this time, which heat must be efliciently and economicallyla) utilized in the translation of heat into mechanical energy and (b) that not'translated into mechanical energy properly dissipated.

A, further object of my invention is the 4 production of a light weight piston adapted to overcome in a large measure the difiiculties known as piston slap and oil pumping.

My present invention comprises improve ments on the invention of Joseph H. Bamberg disclosed in his Letters Patent of the United States NO; 1,296,589. It contem-' plates providing a. relativelylight, durable composite piston, utilizing-the principal advantageous characteristics of the piston invented by Mr. Bamberg and employing a guiding section of material of greater resistivity to wear than the metallic alloys of aluminum now commercially used in piston construction, some of which are referred to in Mr. Bambergs said patent.

Purely for the purposes of disclosure herein 1 have selected to illustrate and describe one construction of internal combustion motor. skirted piston and a modification thereof embodying my improvements.

In the drawings, Figurel is a sideeleva tion of a piston-embodying my improvements.

Fig. 2 is a section on the lme 22, Fig. 1.

Fig. 3 is a section onthe line 3 3, Fig. 2.

Fig. 4 is a bottom plan view. l I Fig. 5 is a section and Fig. 6 a bottom plan view of a modified construction of composite piston embodying my invention.

expand 1 is the skirt, body or guide section of I the piston, which may be made preferably of sheet metal or any material suitable to resist wear in operation within an internal combustion motor cylinder, such for example as a section of drawn steel tubing or steel stamping. This guide section 1 is formed with alined diametrically opposed apertures 1, 1 which preferably are concentric with the axis of the wrist pin bosses, later to be described, to permit the insertion and withdrawal of the wrist pin, as desired, in the well known manner. At its lower end the metal of the section is bent inwardly and back upon itself, as indicated at 1, and formed with an annular inner cylindrical section 1 of reduced diameter.

In order to lighten as much as possible the sheet metal part of the piston, apertures 1 may be formed through the inwardly turned known construction and therebelow may carry diametrically opposed, inwardly extending, annular wrist pin bosses 3.

The section 3 at the lower end of this combined head and connector may be secured to the lower end of the skirt 1 in any suitable manner. In Figs. 2, 3 and 4 I have shown this connection to beefl'ected by'interna'lly screw-threading the section 3 andexternallyscrew-threading the outer surface of portion 1 of-the sheet metal section of 1 the piston. When this connection is made, if desired the wall 3 may be heated so as to i it considerably and the screw threaded portions of the parts 1 and 3 may be screwed together while the part 3 is thus --'heated so as to obtain a shrink fit on this threaded connection.

'The part 3 may be made of any desired material having a relatively low specific gravity and may be formed in any suitable manner; I prefer'to make it of an aluminum alloy cast in a permanent mold and suitabl poured and chilled so that its structure "will be relatively fine-grained and nonporous and the eutectic will substantially surround the excess substance in the structure. For example, this combined head and connector 3 may be made in accordance ,with the invention of Joseph 'Bamberg as set forth and described in his said Letters Patent of the United States No. 1,296,589. lVhere so constructed suitable strengthening webs or ribs 3 may be provided at the head end of the piston, in the now well known manner.

In Fig: 5 T have illustrated another way of connecting the lower end of the element 3 to the inner portion at the lower end of the element 1. In this embodiment of my invention the upper end of the inwardly and upwardly turned portion 1 of the skirt is internally screw-threaded, as indicated at 1 and the section 3 at the lower end of the combined head and connector 3 is correspondingly externally screw-threaded. When this connection is made, if desired, the screwthreaded section 1 of the skirt may be heatedso as to expand it considerably, and the screw-threaded portion of the parts 1 and 3 then may be screwed together while the portion l of the guide section is thus heated so as to obtain a shrink fit on this threaded connection.

Should it be deemed advisable to lock the section 3 to the adjacent inner annular portion of the skirt 1, this may be accomplished after the parts are screwed together by slight distortion or mutilation of one 1 or more of the screw threads, in'any well known manner, not shown.

A plurality of holes 3* are provided through the sheet metal section, preferably where the metal is bent back upon itself to -forn1 the lower end of the piston. These holes or ducts provide oil escapes or drain passages for lubricant or oil which may collect between the skirt 1 and the lower end of thecombined piston head and connecting element 3.-

lit will be understood that the sleeve or skirt 1 may be constructed so as snugly to fit the lnner wall of the motor cylinder which is commonly made of iron or steel, whereas the portion of the head 3 above it may be given a considerable amount of clearance betweenits outer periphery and the inner wall of the cylinder to allow for all necessary expansion of the head due to the high temperatures to which'it is subjected. The heat absorbed by the head is transferred downwardly by the side walls 3 to the lower end of the skirt 1, and much of it is dissipated by radiation, so that the skirt is kept relatively cool and may be readily lubribated to provide and maintain the proper working relationship between it and the inner wall of the motor cylinder with which it co-acts. The fit between the skirt and the inner wall of cylinder, as before indicated, may be a snug sliding fit, and preferably the area of the skirt which co-acts with the inner wall of the motor cylinder is such as to insure aeaeas against slapping or rapping of the piston against the inner wall of the cylinder. In fact, objectionable so-called piston slap, incident to the operation of numerous types of pistons for use in internal combustion motors, substantially is eliminated by the use of a piston constructed in accordance with my invention as shown in the drawings. Furthermore, a piston embodying my improvements herein described practically eliminates so-called oil pumping or transter of an undue amount of oil or lubricant from the crank case to the upper end of the piston, resulting in undesirable smoking and undue'and troublesome carbonization, among other things.

Due to the fact that the sleeve or skirt is maintained relatively cool under all normal working conditions, the possibilities of scoring of the inner walls of the cylinder are practically eliminated.

The upper end of the skirt 1 is separated from the head 3 by an air gap. In the drawings, purely for the purpose of illustration, this air gap is shown relatively wide. The presence of this air gap or air space between the upper edge of the skirt or body section 1 and the adjacent ed e of the piston head, insures that the heat absorbed by the piston head principally will be transmitted inwardly and downwardly so that such portions of it as does reach the skirt or body by conduction will do so at the lower end of the skirt and will not be sufiicient in amount to cause the necessary expansion of the skirt to eflect binding between the skirt'and inner wall of the cylinder or scoring. TVhile this air gap, as above stated, has been shown relatively wide for the purpose of illustration, it will be understood that my invention contemplates any sort of a separated relationship between the upper endof the skirt and the adjacent head 3 because of which heat will not be transmitted eficiently or readily from said head to the skirt. It will be understood that this relationship might be that even of a poor mechanical fit or joint which would be a poor conductor of heat as compared with the metal of the side walls 3 so that such heat as did pass from the head to the guide section 1 would do so principally by way of the side walls 3 rather than from the head to the upper end of the skirt 1.

ltt will be understood that by making the skirt or guide part of my piston of iron or steel ll not only secure good wearing qualities but also a coefiicient or thermal expansion much smaller than those ofthe light weight alloys such as aluminum alloys.

Both this low coeliicient of expansion and the low working temperature-of the piston skirt favor the close working fit of the skirt in the engine cylinder and, at the same time, full advantage is taken of the light weight material of the head and connecting part to reduce the weight of the piston.

By making the headand connecting part of the piston of light weight metal such as aluminum alloy and by forming the skirt of relatively thin steel tubing, the weight of my improved composite plston is made comparable with that of pistons made entirely of aluminum alloys. ihis light weight is, of course," of material advantage in reducing the weight of the reciprocating parts of the engine, and pistons of my improved construction will be found to operate comparatively noiselessly, smoothly and efficiently'.

Certain features of the subject-matter herein disclosed but not claimed, are claimed in my co-pending application Serial No. 110,844, filed July 24, 1916.-

To those skilled in the art, many modifications of and widely difiering embodiments and applications of my invention will suggest themselves, without departing from the spirit and scope thereof. My disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

"What I claim is:

'1. A composite piston for an internal combustion motor comprising a head, wrist pin bosses and an extension below said wrist pin bosses cast integrally of a metallic alloy having a relatively low specific gravity in comparison with iron, and a sheet metal guide section having an outer wall adapted to engage the inner wall of a motor cylinder and a section bent inwardly and upwardly from the lower end of said outer wall and secured to said cast extension below said bosses.

2. A composite piston for an internal combustion motor comprising a liead, wrist pin bosses and an extension below said wristpin bosses cast integrally of a metallic alloy havinga relatively low specific gravity in comparlson with iron, and a sheet metal guide section having an outer wall adapted to engage the mner wall of a motor cylinder and a section bent inwardly and I upwardly from the lower end of said outer wall and sei cured to said extension below said bosses by a shrunk screw threaded connection between the parts. I

3. A composite piston for an internal combustlon motor comprisingia head, wrist pin bosses and an extension below said wrist pin bosses cast integrally of a metallic alloy having a relatively low specific gravity in comparison with iron, and a sheet metal guide section having'an outer wall adapted to engage the inner-wall of a motor cylinder and a section bent inwardly and upwardly from the lower end of said outer wall and securedto said cast extension below said bosses, the

upper edge of the outer wall of said guide section being separated from the adjacent Wall of the head by-a relatively small air gap.

4:. A composite piston for an internal com- 'bustion motor, comprising a sheet metal guide section having an outer wall adapted snugly to fit the inner wall of a motor cylinder, the lower portion of said guide section being turned inwardly and upwardly to form an inner portion of reduced diameter at its upper inner end, and a head, wrist pin bosses and extension below said bosses cast integrally of a metallic alloy having a lower specific gravity than iron, and said extension being secured below said bosses to said upper end of said inner reduced portion of said sheet metal guide section. Y

5. A composite piston for an internal combustion motor, comprising a sheet metal guide section having an outer wall adapted snuglyto fit the inner wall of a motor cylinder, the lower portion of said guide section being turned inwardly and upwardly to form an inner portion of reduced diameter 1 at its upper inner end, and a head, wrist pin bosses and extension below said bosses cast integrally of a metallic alloy having a lower specific gravity than iron, and said extension being secured below said bosses by a screw threaded connection to said upper end of said inner reduced portion of said sheetmetal guide section.

6. A composite piston for an internal combustion motor, comprising a sheet metal guide section having an outer wall adapted snugly to fit the inner wall of a motor cylinder, the lower portion of said guide section being turned inwardly and upwardly to form an inner portion of reduced dimensions at its upper inner end, and a head, wristpin bosses and extension below said bosses cast integrally of a metallic alloy having a 'lower specific gravity than iron, and said extension being secured below said bosses to said-upper inner end of sald reduced portion of said sheet metal guide section, the upper edge of the outer wall of said guide section being separated from the adjacent wall of the head by a relatively small air gap.

7. A composite piston for an internal combustion motor, comprising a cylindrical 1 sheet iron guide section having its outer wall adapted snugly to fit the inner wall of a motor cylinder, the lower free end of said guide section being bent and drawn inwardly and upwardly to form an inner reduced portion, and a head, wrist pin bosses and'extension below said bossescast integrally of a metallic alloy having a lower specific gravity than iron, and said extension being secured below said bosses to the adjacent free end of said geduced portion of said sheet metal cyliner. s 1 8. A composite piston for an internal combustion motor, comprising a head, wrist pin bosses and an extension below said wrist pin bosses cast integrally of a metallic alloy having a low specific gravity and a high 00- eflicient of expansion in comparison with iron, and a guide section made of wear-resisting metal having a low coeficient of expansion in comparison with the said metallic alloy and formed with an elongated cylindrical wall adapted to slidably engage the inner wall of the motor cylinder, the guide section having its upper end separated from the head part of the piston by an air space and its lower end extended inward and upward and secured to the said extension below the wrist pin bosses.

9. A composite piston for an internal combustion motor, comprising a head, wrist pin bosses and an extension below said wrist pin neee eee bosses cast integrally of a metallic alloy having a low specific gravity and a high coeificient of expansion in comparison with iron, and a guide section made of wear-resisting sheet metal having a low coeflicient of expansion in comparison with the said metallic alloy and formed with an elongated cylindrical walladapted to slidably engage the inner wall of the motor cylinder, the guide section having its upper end separated from the head part of the piston by an air space and its lower end extended inward and upward and secured to the said extenion below the wrist pin bosses.

In testimony whereof ll afix my signature.

rnnnnnio a. ranirnnnsr

Images