US1770818A - Piston - Google Patents

Description

'July 1 5 1930- c. E. SUMMERS PISTON Filed Ma 11-, 1927 Patented July is, 1930 UNITED STATES PATENT OFFICE CALE.'B IE. SUMMERS, OI PONTIAC, MICHIGAN, ASSIGNOR TO GENERAL MOTORS COR- PORATION, OF DETROIT, MICHIGAN, A CORPORATION OIPDELAWARE PISTON Application filed Kay 11,

This invention relates to pistons for internal combustion engines used on automotive vehicles. 7

' It is the object of the present invention to construct a two-piece piston having ahead portion of one kind of metal and a skirt portion of a different kind. The metal for the head portion is preferably one whichis of relative light weight and which, at the same time, has a good thermal conductivity, while the metal for'the skirt portion has relatively large wear resisting qualities and also a relatively For the head of the piston'I preferably use '1 aluminum and forthe skirt portion a progerly alloyed and heat treated-steel is to preferred.

Inasmuch as two kinds of metal are used, they will have difierent coeificients of expan-" sion and I accordingly design the two parts form an inwill be so proporsurface will be in regardless of the so that their meeting edges will clined surface and they tioned that this meeting firm contact at all times,

temperature to which the istonis subjected during the operation of tile engine. The head of the piston is provided with two downwardly projecting webs, at the end of which I form bearing boxes for the reception of the pin of the connecting'rod. The skirt portion is provided with openings having boss formations which are concentric with the bearing boxes and intO'which the ends of the piston pin is'received.

The head of the piston is castand in order to unite the skirt portion to the head portion. I provide two brackets about which the head is cast so that they form a substantially integral structure therewith. These brackets project laterally from the bearing boxes and have flanged ends to which the skirt portion is secured, for example, by welding.

As a modification I may cast'the head portion into the skirt portion andprovide flanges 1 .on the skirt around which themetal of the.

parts rigidly together.- I may also provide and into which formations the cast metal may low thermal coeflicient of expansion. I

" head is hollow,

'piston rod to the piston 10.

properly dovetailed formations on parts of the skirt;.

1927. Serial No. 190,5 59.

flow in order to secure a more intimate connection between the head and skirt ortion.

' he invention is disclosed in t e accompanying drawing in which: ig. 1 is a view in elevation of a piston constructed in accordance with my invention with parts shown in sectionfor purposes of clearer illustration. Fig. 2 is a section on the line 22 of Fi 1. Fig. 3 is a section on the lines 3-3 of lgs. 1 and 2.

' Fig. 4 is a sectional view of a modification. Fig. 5 is a-sectional' view on the line 5-5 of Fig. 4. Referring to the numbered parts on the drawing, 10 indicates-my improved pistonas a whole, 11 is the upper part or head portion, and 12 the lower part or skirt portion.

he head is cast of a metal which preferably has a good thermal conductivity and at the same time is relatively light in weight,

which strengthens the entire structure. The I except for the rib l6, wh ich makes for a very light structure.

The ends of the webs 14 and 15 terminate in enlarged portion'sT forming boxes 17 and 18, having openings 19 and 20, respectively, for the reception of the pin which pivots the By referring to Figs. 1 .and'2' it will be noted that the head hasan inclined surface at 21 which extends around the periphery and the purpose of which will be laterde-v scribed. p At the time of-the casting of the cylinder. head 11 a pair of. brackets 22 and 23 are positioned in the mold so that the box portions at the ends of the webs 14 and- 15 will embed the brackets so as to make them substantially integral with the piston head.

Thesebrackets have central openings as at 24 head may be cast in order to hold the two conforming to the openings 19 and 20 of the boxes 17 and 18 to allow for the passage of the connecting bolt an'd theseopenings are. flanged so as to obtain a close contact between the head and the brackets and to more from a blank and later rolled into its finished shape for assembly with the head portion. The skirt has the stiffening ribs 26 and at its meeting place with the head 11 it has an inclined flanged edge 27, complementary to the inclined edge 21. The construction of the head 11 and skirt 12 is such that when the heating of the piston takes place during the operation of the engine, the difference in the coefiicients of expansion of the two metals is such that a tight contact between the surfaces as 21 and 27 will be maintained at all times.

At the meeting edges of the skirt portion when rolled together I preferably provide tabs 28 which may be welded together to hold the skirt in its circular form. The entire seam may also be welded if desired.

The skirt is attached to the head structure by means of the flanges 25 on the ends of the brackets 22 and 23. By referring to Fig. 3 it will be noted that these flanges conform to the circular shape of the skirt as shown I at 29 and at which meeting surfaces the skirt and bracket are united by any suitable means, welding being preferred.

The skirt is also provided with two openings 30 and 31', having inwardly extending bosses 32 and 33, which conform to and are concentric with the openings 19 and 20 of the piston head 11. By referring to Figs. 2

of the bearing surfaces.

and 3 it will be noted that there is a close contact as shown at 34 between the bosses 32 and 33 and the bearing boxes 17 and 18.

The species of Figs. 4 and 5 diflers from that of Fi s. 1 to 3 in that the head 11 is cast into t e skirt portion 12. The downwardly extending webs 14' are cast into the dovetailed portions 35 of'inwardly bent tabs 36 on the skirt 12 to give a close contact and insure a more intimate connection between the head 11 and skirt 12'. species the bosses 32' and 33 are surrounded by the cast metal from the head 11 forming a structure which is substantially integral and which is very ri 'd.

In all species, the bbttom of the skirt portion is inturned as at 37 giving a rounded edge as shown at 39.

I claim: 1'

1. In a piston, a head portion, bearing "members in said head having bearing surfaces, a skirt portion abutting and forming a continuation of said head, and bosses on' said skirt in alignment with said bearing members, said bosses forming a continuatio .2. In a'two part piston, an upper part, a

I plurality of-webs extending'from'said upper part,bearing boxes at'the .end of said webs,

In this said boxes having bearing surfaces, a lower part, bearing boxes at the end of said webs,

said boxes having bearing surfaces, a lower part surrounding said webs and bearing boxes, bosses on said lower portion concentric with said boxes,'said-bosses forming a continuation of said surfaces, means to secure said parts together, and a single inclined'peripheral edge on eachsaid head and skirt, said edges complementary to each other and forming the sole peripheral contact.

4. In a two part piston, an upper part, a plurality of webs extending from said upper part, bearing boxes at the end of said webs,

said boxes having bearingsurfaces, a lower part surrounding said webs and bearing oxes, bosses on said lower portion concentric with said boxes, said bosses forming a continuation of said surfaces, means to se; cure said parts together, and a single inclined peripheral meeting edge on each of said head and skirt, said edges complementary to eachother and forming the sole peripheral con tact, said inclined surfaces being such that the relative expansion of the metals of the head and'of the skirt will keep the two parts in firm contact at all times.

5. In a two part piston, a skirt portion, a head portion cast into said skirt portion, bearing portions. formed on said head portion, and bosses and'tabs on said skirt portion into which said head is cast, said bosses arranged concentric with said bearing portions and said tabs positioned circumferentially below and spaced from said bosses.

6. 'In a piston, a plurality of separate brackets, a head portion cast about a portion of said brackets, a skirt portion formed sepafate from said brackets and forming the lower end of said piston, said skirt portion secured to the ends of said brackets, said bracket portion in said head having a flanged -or bent edge.

skirt portion secured to the ends' of said brackets, said brackets having their midpor-;

tions provided with bent edges to firmly hold them in the cast'head and their ends flanged .to afiord a securing means betweenthe piston and skirt.

8. In a piston, a cast head portion, an inclined or tapered peripheral or circumferential edge at the lower-most circumferential portion of said head, a skirt portion secured to said head, and an inturned inclined flange on the upper end of said skirt, said flange abutting with and conforming to said inclined or tapered portion of said head.

9. In a piston, a cast head portion, an inclined or tapered peripheral or circumferential edge at the lowermost circumferential portion of said head, a skirt portion, a plurality of brackets having said head portion cast about their mid portions, said brackets extending away from their cast connection and secured to said skirt at their ends, and an inturned inclined flange on the upper end of said skirt, said flange abutting with and conforming to said inclined or tapered portion of said head.

In testimony whereof I afiix my signature.

' CALEB E. SUMMERS.

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