US1293846A - Piston. - Google Patents

Description

H. C. MARA/50N.

FISTON.

APPLICATION FILED JULY 10,1916.

Patented Febl 11, 1919.

. s'ra s PA PISTON.

Specification of Letters Patent.

atented Feb. 11, 1919.

Application led July 10, 1916. Serial No. 108.274.

of my invention is to produce an eliiclent piston,

especially designed for use in internal combustion engines, the construction being such as to permit a practical elimination of slapping due to the necessity, in piston structures rnost commonly now in use, of providing'suliicient clearance or looseness of fit, throughout the length of the lpiston to compensate for expansion due pin,

to heating.

The accompanying drawings illustrate my invention. Figure 1 is an axial sectionof my improved piston; Fig. 2 an axial section. at fright angles to the plane of Fig. 1; Fig. 3 a sideelevation in partial axial section -of a modified form; and'Fig. 4 a section on line .4-4 of Fig. 2.

,In the drawings, indicates the head, or ring-carrying portion of the piston, provided with the usual circumferential ringrecelving grooves 11, designed to receive packing ring'sof desired construction.

The head portion 10 1s comp'aratlvely short as to' that portion which carries the `rings and diametrically may be given sufficient clearance to compensate for all possible increase of diameter due to heating. The head 10 is, however, provided with an axially-extended tubular stem, or shank, 12, of considerably less diameter than the diameter of the ring-carrying portion and at its end this shank or stem is provided with an external circumferential flange 13, which is of less diameter than the ring-carrying portion. At diametrically opposite points, the stem 12 is provided, both externally and internally, with bosses 14 which are bored to form pin-receiving openings 15 for the wrist these bosses being preferably arranged as near the lower end of the shank as possible, as clearly shown in the drawing.

The main guide portion or cross-head portion of the piston is formed by an accurately fitted skirt attached to the lower end of the sleeve 12 in such manner that it is, in the main, isolated from the head section, its point of attachment bein so remote from that portion of the head o? the piston which is directly affected by the heat, that there will be comparatively little conduction of' `a lower depending skirt 17, and an intermediate inwardly-projecting flange 18 mating with flange 13 and attached thereto by bolts 1 9 and nuts 20, the nuts being tightened and then held in place -by peening the end of the bolt. The skirts 16 and 17 may be made very thin and carefullymachined inside and out in order'v to be perfectly balanced. In the form shown in Fig. 3, the upwardly projecting skirt section 16 is formed ofisheet metal having an inturned flange 22 at one end and the` depending skirt section 17 is also formed of sheet metal and provided with an inturned flange 23 at one end. Flange 22 is formed to fit upon flange 13 of the head section and flange `23 is formed to rest upon flange 22, the two skirt sections being held in place by bolts 19 and nuts` 20, as in the other construction. The two skirt sections, having been placed in position, may be accurately externally ground to fit the cylinder into which the piston is to go, and the circumferential crease 24 formed at the junction of the two skirt sections will serve as a reservoir for lubricant. l

The upwardly extending skirt section, in either form, extends up close to the larger portion of head 10, but is at all points separated therefrom, so that there can be no direct transmission of heat from the head portion to the skirt. In order to permit the ready insertion of the wrist pin, the upwardly extending skirt 16, or 16', is perforated at 25.

During the operation, there would be an accumulation of oil in the annular space between the upwardly presented skirt 16` and the tubular stem 12, and in order to prevent too great an accumulation of oil, I slitk the lower end of the stem 12 at various points by the longitudinal slots 27 which may extend, if desired, entirely through the flange 13 and up far enough to form outlets for the annular space referred to.

In practice I have found that, with the form shown in Figs. 1 and 2, most excellent results can be obtained by making the main body or head portion of the structure of aluminum and the skirt section of cast iron. In the form shown in Fig. 3, the head section may be of aluminum and the skirt sections may be of pressed steel.

In the manufacture of automobile engines at the present time, where the piston speeds are very high. itis very essential that the pistons be not only as light as possible, but that they be as accurately balanced as possible and it is, therefore, important that the skirt section, or sections, be separate from the head section, not only because the necessary stiffness of the skirt member may be obtained by the use of a material different from that used for the head, but' 4also because both the head and the skirt may be carefully machined inside land out and thus proper balancing obtained. No such accuracy of balance could be obtained by a structure in which the skirts vwere integral with the main body. f

I claim as my' invention:

1. A piston comprisin a head section hav'- ing a tubularshank o less diameter than the active end and of sufficient length to re- .ceive the pitman wrist pin, a skirted cross head section formedV independently of the head section, said skirted cross head section comprising an upwardly extended skirt overlying the tubular shankbut radially separated therefrom, and also comprising a dependingskirt, and also comprising an inwardly projecting portion formed to mate with the tubular stem, and means for fastening the skirted cross head to the head member at a point distant from theaotivev end of said hea-d member.

2. A piston structure comprisin a head member havin-g an axially extende portion of less diameter than its active end and provided at the free end of this extended portion with a laterally extended bolt-receiving portion; and a cross head member comprising a skirt portion formed independently of the head member and overlying the axially extended portion of the head member 'but separated therefrom, and also comprising an inwardly projected portion mating with the laterally projected portion of the head member; fastening bolts connecting said mating portions.

3. A piston comprising a head member having an axially extended portion of less diameteithan the active end and provided at the free end of this extended-portion with an external circumferential flange; a cross head member having an internal circumferential flange and a skirt portion overlying the axially extended portion `of the head member but radially separated therefrom, the said cross head member being formed independently of the head member; hea-ded bolts passing through the flanges of the head member and cross head member with the heads thereof engaging the'ilange o f the head member, and nuts clamping the cross head member upon the head member.

4. A piston comprisin a head member having an axially exten ed portion of less diameter than the active end a'nd provided at the free end of this extended portion with portions formed to mate with a cross head member; a cross head member comprising a pair of oppositely arranged sheet metal skirts each provided at one end with an inwardly extending flange, the said inwardly extending flanges being formed -to mate with each other and with the appropriate portion of the head member, and fastening members clamping the head member and cross head members together.

5. A piston comprisin a head member having an axially exten ed portion of less diameter than the active end and provided at the free end of this extended portion with an extern-al circumferential flange, said axially extended portion having wrist pin receiving perforations between the active end ferential flange, and having a skirt portion overlying the small extended portion of the head member and extending beyond the wrist pin perforation, said skirt member having perforations permitting the lateral insertion of the wrist pin and bolts for clamping the cross head member to the head member.

6. A piston structure comprisin a head member having an axially extended portion of less diameter than its active end and provided at the free end of said extended V portion with a lateral extension; a cross h'ead comprising a mating pair of skirt sections each formed of sheet metal and provided flange at one end., said flanges at their mating planes forming a circumferential crease in the cross head; and means for clamping said inwardly projecting flanges together upon the lateral extension of the head member.

7. A piston structure comprisin a head member having an axially extende portion of less diameter than its active end and provided at the free end of this extended portion with a laterally extended bolt-receiving portion; and a cross head member comprisin g a skirt portion formed independently of the head member and overlying the axially extended portion of the head member but with an inwardly extending circumferential separated therefrom, and also comprising an external eircmnferential ange, said axialiy extended portion having Wrist pin receiving perforations between the active end and said circumferential Bange; perfora- 5 tions between the active end and said` eireumferential flange; a cross head member having an' internalpeircumferential. ange mating with the said external circumferential ange, and havin a skirt portion 0 overlying the small exten ed portion of the head member and extending beyond the wrist pin perforation, said skirt member havin perforations permitting the lateral` insertion of the Wrist pin; and means for clamping the Cross head member tothe head 15 member. i

In Witness whereof, I have hereunto set my hand at Indianapolis, Indiana, this sixth day of July A. D. one thousand nine hundred. and sixteen.,

HOWARD C. MARMON.

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