US2311584A - Expansible piston - Google Patents

Description

Feb. 16, 1943. w. G. swlF'T 2,311,584

EXPANSIBLE PISTON Filed Nov. 25, 1941 2 Sheets-Sheet 1 Patented Feb. 16, 1943 UNETED STATES i ATEN'i' GFFICE EXPANSIBLE PISTON Walter G. Swift, Flint, Mich.

Application November 25, 1941, Serial No. 426,416

4 Claims.

This invention relates to pistons.

An object of this invention is to provide a piston structure including a ring carrying head formed with depending wrist-pin bosses or bearings, and a split expandible skirt removably secured to and encompassing the bosses.

Another object of this invention is to provide a piston with an expandible split skirt which is removably mounted on the head or body of the piston, so that it will not be necessary to replace the piston when the cylinder becomes worn and new rings are inserted in the grooves of the piston.

A further object of this invention is to provide in an expandible piston skirt an improved adjusting means so that the amount of expansion or enlargement can be accurately gauged withut the use of calipers or a micrometer, the adjusting means including a calibrated screw and graduations correlated with the skirt so that turning of the adjusting and holding screw will efiect expansion or contraction of the skirt in the desired amount.

A further object of this invention is to provide in an adjusting means of this kind an improved means for locking the adjusting screw in its adjusted position so as to prevent expansion of the skirt under operating conditions.

To the foregoing objects and others which may hereinafter appear, the invention consists of the novel construction, combination and arrangement of parts as will be more specifically referred to and illustrated in the accompanying drawings, but it is to be understood that changes, variations and modifications may be resorted to which fall within the scope of the invention as claimed.

In the drawings:

Figure 1 is a detail side elevation of a piston constructed according to an embodiment of this invention,

Figure 2 is a detail bottom plan of the piston,

Figure 3 is a sectional view taken on the line 3-3 of Figure 1,

Figure 4 is a sectional view partly broken away taken on the line 4-4 of Figure 1,

Figure 5 is a sectional view taken on the line 5-5 of Figure 4,

Figure 6 is a fragmentary side elevation of the lower portion of the piston,

Figure 7 is a fragmentary sectional view taken on the line l'! of Figure 1, and

Figure 8 is a fragmentary sectional view taken on the line 88 of Figure 7.

Referring to the drawings the numeral I0 the skirt designates generally a piston structure which includes a head H and a skirt portion I2. The head I! is formed with a top wall l3 and a cylindrical side wall M which is formed with a plurality of ring receiving grooves 15. The side wall [4 is also formed with diametrically opposed oil passages or openings I6 which communicate with the oil ring receiving groove I5 in the lower portion of the side Wall l4.

The head H has formed integral therewith a pair of depending wrist-pin receiving bosses or bearings l! which extend below the cylindrical wall 14 and which are dependingly supported below the wall [4 by pairs of vertically disposed ribs l8. The ribs I8 extend upwardly to the top wall l3, and a pair of upper parallel ribs #9 are formed integral with the top wall l3 and also with the depending ribs I8. The outer ends of the bosses or bearings I! are inwardly offset from the peripheral surface of the side wall [4, and the skirt I2 snugly engages about the outer ends of the bearings 20. The peripheral surface of I2 is substantially flush with the peripheral surface of the side wall [4.

The skirt [2 includes a cylindrical body 2! which is longitudinally split as at 22. The skirt 2| is formed of resilient material and is of a construction such that the skirt 2| will normally expand in order that the exterior diameter-of the skirt 2! may, as hereinafter described, be adjusted to the desired diameter for sliding contact with the surface of the cylinder wall. The skirt i2 has formed integral therewith a pair -of diametrically disposed inwardly projecting flanges 23 which are adapted to engage against seats 24 which are formed at the lower ends of the bearing bosses H. The flanges 23 are of segment shape in plane and are each provided with a pair of openings 25 through which fastening devices 26 are threaded into threaded openings 21 which are formed in the bearings I1, and a resilient spring washer 28 is interposed between the head of each fastening device 26 and the adjacent side of the flange 23. The flange 23 is also provided with a recess 29 within which the spring washer 28 is adapted to snugly engage as shown in Figure 4.

The kirt body 2| on opposite sides of the split portion 22 thereof has formed integral therewith a pair of confronting and parallel cars 33 and 3|. The cars 30 and 31 extend inwardly from the inner side of the skirt 2! on opposite sides of the split portion 22 thereof, and a cap screw or fastening device 32 is extended through an opening 33 formed in the ear 3|, and is threaded into a.

' the recess 36.

threaded opening 34 which is formed in the ear 3!). In order to provide ameans whereby the fastening or skirt adjusting member 32 may be locked in its adjusted position, I have provided a bolt or screw clamping block 35 which is seated in a recess 36 formed in the lower side of the car 30. The threaded opening 34 communicates with the recess 36 at the bottom of the recess so that the upper side of the block 35 will contact with the threads of the bolt or fastening device 32.

The recess 36 as shown in Figures 2 and 7 is formed with parallel sides 31 and rounded ends 38. The block 35 has a configuration substantially coincident with the configuration of the recess 36 and is adapted to loosely engage within A clamping screw or bolt- 39 is threaded into the ear 3% and extends loosely through an opening 49 which is formed in the clamping block 35. Tightening of the screw or bolt 39 will place pressure on the block 35 and cause this block 35 to tightly bear against the threads of the screw or bolt 32.

The bolt or screw 32 is adapted to be tightened or loosened by means of a tool which may be extended through an elongated opening 45 which is formed in' the skirt wall 2i. The belt or screw 32 is preferably so constructed that when it is turned in either direction to either loosen or tighten the skirt 2! with respect to the cylinder of the engine, the workman can accurately deter; mine the amount of expansion or contraction. This is accomplished by providing the outer face 42 of the ear 3! with a plurality of radially arranged graduations 53 having 'indicia' 54 stamped thereon. The head 45 of the fastening device 32 is provided with a pointer 43 correlated with the graduations 43 and indicia til, so that when a tool such as a screwdriver or the like, is inserted in the kerf it! of the screw 32, the screw may be turned in the desired direction and for the desired amount to effect a predetermined expansion or contraction of the skirt wall 2|.

In the use and operation of this piston structure the piston head It is adapted to have the desired rings mounted the grooves l and I5 thereof, and the wrist-pin at the upper end of the connecting rod is adapted to engage in the bearing bosses ll. The skirt I2 is secured by the fastening devices 26 to the lower ends of the bearings I '1', and the openings 25 for the fastening device 26 are preferably substantially larger in diameter than the outside diameter of the screws The purpose for these larger openings 25 is to permit the desired expansion or contraction of the skirt l2. In the event it is desired to expand the skirt 12, in order that this skirt may snugly and slidingly engage the inner surface of the engin cylinder wall, the clamping screw or bolt 39 is loosened, thereby relieving the adjusting screw 32 from pressure from the clamping block 35. The adjusting screw 32 may then be turned in a counterclockwise direction, thereby permitting the skirt 2| to expand for the desired distance. The amount of expansion of the skirt 2| may be definitely and accurately determined .by th position of the pointer 46 with respect to the graduations 43 and the indicla, 44 which are carried by the outer side of the ear 3|.

With a piston structure as hereinbefore described it is possible to provide for replacement of the skirt portion of the piston without replacement of the head portion of the piston, and in the event larger rings are inserted in the ring grooves l5 and I5 due to wear of the prior rings and Wear of the side wall 12 of the piston together with wear of the cylinder wall, the piston slap in the cylinders may be eliminated by expansion of the skirt 2 I as hereinbefore described, or by complete replacement of the skirt, if such procedure should be necessary or desirable.

What I claim is:

1. A piston comprising a grooved head, a pair of wristpin bearings, means dependingly'supporting said bearings from-'said 'head, a resilient split expandible skirt encompassing j-said bearings, a

- pair of diametrically opposed inwardly projecting flanges integral with said skirtgmeans 'detachably securing said skirt to said bearings, a pair of opposed inwardly projecting 'ea'rs carried by said skirt on opposite sides of 'the'split portions thereof, and means engaging said ears for holding said skirt in a predetermined expanded position.

2. In a piston having a head, a removable split skirt, means removably securing the skirt "on the head, said skirt including a resiliently expansible split skirt body, 'a pair of parallel inwardly proing through one of said ears and threaded into the'other ear for regulating the expansion of said skirt, and means for locking said latter means against movement.

4:. In a piston having a head, a removable split skirt, means removably securinguthe skirt on the head, said skirt including a resiliently expansible split skirt body, a pair "of parallel inwardly projecting ears carriedby said skirt on opposite sidesof the split portion thereof, an expansion regulating screw loosely engaging through one ear and threaded into the other ear, graduations carried by the outer side of said one ear, and a pointer carried by said screw whereby the 'degree of expansion may be accurately determined.

WALTER Gr SWIFT.

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