US2258476A - Piston recammer - Google Patents

Description

D. J. WHERRY PISTON RECAMMER Oct; 7, 1941.

Filed July- 3, 1940 5 e WM, r K d m M FIG. 3

- portion 3 depending from the head. Inwardly Patented Oct. 7, 1941 UNITED STATES PATENT OFFICE 2,258,476 rrs'ron nncamma Dale J. When-y, St. Louis, Mo. Application July 3, 1940, Serial N... 243,694

(or soc-12) 2 Claims.

This invention relates to improvements in piston construction and more particularly to means adapted to be used in connection with solid skirt pistons that have become worn or out-of-round, so as to re-cam the latter or re-shape them to substantially their original shape.

the likelihood of causing the pistons to rapidly wear through along the points where the thrust holding them expanded is being exerted.

Other objects of this invention are to construct a device of the kind described, which will be extremely simple in construction and installation, which shall not require any extraneous alterations or securement to the piston structure to retain the re-cammer securely in its place, of low cost, and which will be otherwise efiicient and satisfactory for use wherever deemed appli- Cable.

Many other objects and advantages of the construction herein shown and described, and the uses mentioned, will be obvious to those skilled in the art to which this invention appeartains, as will be apparent from the disclosures herein given.

To this end, my invention consists in the novel construction, arrangement and combination of parts herein shown and described, and the uses mentioned, as will .be more clearly pointed out through a piston showing my device in operative position therein;

Figure 2 is a vertical cross-sectional view, with portions in elevation, taken substantially at right angles to Fig. 1;

Figure 3 is a transverse cross-sectional view,

taken substantially along the line 3 3 of Fig. 1;

Figure 4 is a diagrammatic plan view, showing the' piston before and after re-shaping.

Referring mor particularly to the drawing,

wherein I have illustrated a preferredembodiment of 'my invention, thereis shown a piston of a well-known type, comprising a closed or head end I having the packing ring grooves 2 immediately therebelow, and with the skirt or trunk vided on the interior of the skirt to define the upper and lower limits of the interior of the latter,"somewhat as shown. These pistons are preferably machine-ground to their peripheral contour, controlled .by some sort of a cam means. Inwardly directed projections or bosses 6-6 are formed about mid-height of the skirt, and into these bosses there is secured the wrist pin I. It is to be particularly noted that this .type of piston is not provided with any expansion slot through its skirt wall, extending substantially longitudinally upwardly from its bottom edge, so that this type of piston is best described as a solid skirt piston, having no interruptions or openings about its circumference, except of course thoseopenings shown to receive the ends of the wrist pin.

Although it is admittedly old to expand slotted skirt pistons, it is much more diiiicult to reshape worn solid-skirt pistons to their substantially initially circular cross-section. One reason is because these pistons have unusually-thin skirts, running around .040" or .050" thick, and there is danger of wearing through with localized presure outwardly through the skirt.

Solid skirt pistons of'the type shown are of steel or some other similarly strong material comparatively more resistant to expansion than the alloy or aluminium pistons of the slotted type. so that the re-cammer or re-shaper must be strong enough to perform its intended function and 'yet not damage the piston either in installation or in service.

With this in mind, I have constructed a recammer or re-shaper adapted to be'readily installed into the solid skirt steel piston, after the latter has become worn or out-o -round, without the necessity of using any fastening means or of doing any working upon the piston, this device being simply snapped into position from the open end of the skirt and being thereafter retained in place by the inherent resiliency or springiness metal, say about .02" thick, formed into a channel or U-shaped shell member 8 having the pair of spaced leg portions 9--! joined by the main body portion In. This intermediate portion 10 is provided with an expansion fold or trough ll extending longitudinally centrally thereof, this fold projecting outwardly beyond the main body portion 10, so that when the device is inserted in operative position, as shown in Fig. 3, only the terior of the skirt wall.

The edges of the legs are provided with arcuate or curved recesses I2 intermediate their length, with the lower ends of the recesses projecting outwardly a slight distance beyond the upper ends of the same, as shown most clearly in Fig. 2, so that the device may be inserted into the position shown in Fig. 2 more readily.

The device is of such a size that when it is inserted into the skirt of the worn piston, the fold it is of substantially the same length as the piston skirt, so that the fold portion is engaged at the top and bottom ends by the shoulders 4 and 5.

The leg portions of the re-shaper are preferably tapered from the main. body portion to the free edges, not only to decrease the weight of the same, but in order not to interfere with the normal movement of the connecting rod, with the flow of lubricant within the piston, or in any other manner decrease the efliciency of the cooperating parts.

The distance between the leg portions of the re-shaper are preferably slightly greater than the distance between the abutments against which said portions press after installation in the piston, so that it is required to slightly compress these legs during installation, whereupon they spring apart after release of the installing tool.

The curved recesses of the leg portions snap onto and interlock with the wrist pin, partially embracing the latter, and. in addition they'abut the opposed ends of the pin bosses, and it is obvious that the inherent resiliency of this onepiece re-shaper when sprung and snapped into position, will cause the latter to exert a laterally outward pressure against the unslotted skirt, suflicient to re-shape the skirt and cause the latter to resume its initially substantially circular shape,

this pressure being uniform and even for the full length of the skirt.

fold or rib portion II will engage with the in- In Fig. 4, the dotted lines indicate the out-ofround shape of the piston skirt (with the wrist pin, not shown, in the direction indicated in Fig. 3), and the full line indicates the shape after the re-shaper member has been snapped into place, the change in peripheral outline taking place entirely all along the skirt, and not being localized thereabout.

Having thus described my invention, it is obvious that various immaterial modifications may be made in the same without departing from the spirit of my invention; hence I do not wish to be understood as limiting myself to the exact form,

arrangement, construction and combinations of parts shown, except as limited by the state of the art to which this invention appertains and the claims hereunto appended.

What I claim as new and desire to secure by Letters Patent is:

l. The combination with a piston having a substantially circumferentially-continuous skirt carrying an interior projection; of a spring metal readily detachable shell member sprung into place between said projection and the interior of said skirt, said shell having an outward expansion fold intermediate its lateral edges to engage and exert an outward thrust on said skirt therealong.

2. The combination with a piston having a substantially circumferentially-continuous skirt; and a wrist pin transversely through said skirt; of a resilient channel-shaped cross-section member of relatively very thin metal having curved recesses in the edges and with an. outwardly projecting expansion fold intermediate said edges, so that said member may be detachably sprung into place between said skirt and pin with substantially only said expansion fold engaging along the interiorof the skirt and with said curved recesses partially embracing said pin.

DALE J. WHERRY.

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