US2339538A - Method of forming piston rings - Google Patents

Description

1811- 1944. v. F. ZAHODIAKIN METHOD OF FORMING,PISTON RINGS Filed Oct. 17, 1940 //v VEN TOR By ;W@ M MA 7' TOR/VEVS Patented Jan. 18, '1944 UNITED STATES PATENT OFFICE 2,339,588 METHOD OF FORMING PISTON RINGS Victor F. Zahodiakin, Maplewood, N. J. v Application October 17, 1940, Serial No. 361,484

Claims.

bustion engines but is not limited to thi use.

It is capable of use, with the same advantages, as the oil ring for the pistons of pumps, steam engines or any installation where it is necessary to prevent the escape of oil along the cylinder wall past the piston.

The ring disclosed in the aforesaid co-pending application is formed from a single strip of metal to provide a structure embodying box-like or U- shaped segments open to the side facing the cylinder wall and having perforated back walls. Thus, in radial cross-section, the respective segments appear U-shaped. The sections are integrally connected by spring loops, which loops are disposed between the top and bottom walls of the ring, thereby forming spacers and supports upon which the walls are supported as the loops flex The advantages of this type of ring are fully set forth in the co-pending application.

It has been the object of the inventor in this application to provide a method of constructing the improved piston ring, whereby it is made from a single strip of metal in an extremely sim-.

pl manner by forming the basic structure of the complete ring in punch press or stamping operations and thereafter completing the ring by bending operations performed on this basic structure.

It ha been the broad object of this inventor to provide a method of forming the ring, which method utilizes the simple operations of punching and bending, the die constructions being of the utmost simplicity and the ring resulting from the method steps being accurately formed and uniform in all of its dimensions Other advantages or the invention will be more fully apparent from the description of the drawing in which:

Figure l is a top plan view of a strip of metal,

showing the portions thereof in various stages of formation culminating in the complete ring structure at the right-hand end.

Figure 2 is a general view looking at th side edge of the strip showing it passing through the various mechanisms performing th method steps.

Figure 3 is a sectional view taken on line 3-3, Figure 2, detailing the die which removes certain of the metal prior to the bending operations Figure 4 is a sectional view taken on line 4-4,

Figure 2, illustrating the loop forming die in .de tail. 1 y

Figure 5 is a sectional view taken on line 5-5,

Figure 2, illustrating in detail the bending dies.

which form the top and bottom walls of the respective segments of the ring.

Figure 6 is a view taken similar to Figure 5 but illustrating the die of Figure 5 in its advanced position wherein the walls are formed. 7

Referring to the drawing, a flat strip of metal, I0 is fed into the die and bending mechanisms by means of a feeding mechanism (not shown). The strip passes between elements H and I2 and is gripped after each advance by a holding finger l3. This holding finger I3 is swung on a pivot 14 by pressure applied at its lower or outer end [5 for gripping the strip against the upper element Il,as at I6. 1

The strip passes .over a punching table or platen H. A punch indicated at l8, cooperating with an aperture 19 in the table, forms the oil clearance apertures 20. Each time the strip pauses, this punch descends to punch a hole.

On the next advance of the strip, assuming that this is the first hole to be formed, a pilot pin 2| engages the opening 20 and indexes with the bore 22 in the table.

Th next operation is performed by means of a set of four dies 23. These .dies cooperate with bores 24 in the table and are effective for forming a'series of small holes in rectangular relationship about the respective apertures 20. These apertures 25 define the corners of the cut-out portions of the metal, that is to say, that portion of the metal lying within a zone defined by a line drawn between the adjacent apertures of adjacentsets and extended from these apertures to the sides of the strip. The purpos of formin or defining these corners is to prevent bunching or folding of the metal in the corners as the metal removing dies operate. The next operation is performed upon the strip by means of metal removing dies 26 .of which there are a pair operating in dove-tail slots 21 in th respective side edges of the, table. These dies descend upon the strip, particularly that area defined hereto fore, for removing the metal as illustrated. These notch portions provide edges 28 flared inwardly toward each other toward the outer edges of the strip.

Now as to this group of mechanisms, it will be noted that alter the pilot pin descends, three die erally in this operation by means of a pair of dies 30, 3|, male and female respectively. These die elements operate upon the narrow portion 32 of the metal left after the cut out portions are removed. Thus the portions 33 which are to constitute the top and bottom walls of the ring segments are drawn close together into substantial abutment with their edges 29-29 slightly spaced.

In the next operation, the strip is engaged between a pair of dies 34, 35, male and female respectively. These dies are shown in Figures 5 and 6, and turn the portions 33 at right angles to the portions 32. Thus the box-like segments are completed.

In the next operation, the loops 29 are engaged by means of dies or the wall portions 33 and effective for gripping and forming the loops. These dies provide arouate forming ends thereby pressing the loops into semi-circular form. At the same time as the loops are drawn together, the ring is formed into generally circular form as indicated generally at 31. It will be noted at this time that the edges 28 of the notched out portions are moved into positions where they are radially disposed relative to the center of the ring and are very minutely spaced.

The loop completing mechanism is generally indicated at 38 and includes the dies or fingers 36 operated bymeans of a ram 39 carrying a roller 40. The roller engages inclined surfaces 4| of the fingers 36. These inclined portions face each other and flare inwardly so-the roller is effective in spreading the outer ends of the finger and clamping the inner ends of the fingers together as the ram moves in. A coil spring 42 under tension between pins 43 adjacent the ram is effective for spreading the fingers when theram retreats.

When the strip passes beyond the dies 30, 3! it is obvious that the longitudinal feed of the strip still being in the same stages as before, that is equal to the distances between the punch l8 and the pilot pin 2!, a different timing for the dies 34, 35 and 38, 36 will be required. These dies will act oftener and their operations will be synchronized with the operations of the rest of the dies. In order to accommodate for inaccuracies ln-timing, a certain amount of slack is provided between the dies 30, 3| and dies 34, 35, and between dies 34, 35 and dies 36. 36. Also the device 38 is fed into and out of the strip as a unit in order to clear the preceding and next succeeding loops.

Thus the finished ring provides segments, U- shapedor box-like in form, consisting of the back walls, 44 and top and bottom walls 33 with an aperture 20 in the back wall of each. These sections are connected by the loops 29 and provide the necessary flexibility for the ring The edges 28 of'the sections are. disposed relatively close together on radial lines and thus the ring is free fingers 36 operating between i to flex with the minute spacing preventing loss of oil between the sections.

Having described my invention, I claim:

1. A method of forming a piston ring from a strip of metal comprising the steps oi; punching the metal of the strip to provide segments connected by narrow strips; bending said narrow strips to provide open throated loops at right angles to the strip; bending the laterally extended portions of the segments toward each other and in parallelism in position overlying and engaging the ends of the loops thereby substantially closing the throats of the loops and drawing the U-shaped portions of the strip closer together;

bending the strip into circular form with the loops projected radially outwardly.

2. A method of forming a piston ring consisting of the steps of; forming a strip of metal to provide a blank having laterally adjacent notches along its respective edges; forming the strip portions intermediate respective laterally adjacent notches into open throated loops; bending the portions of metal lying between the notches along each edge of the strip toward each other into position overlying the loops to form U-shaped sections; compressing the strip on itself lineally to close the throats of the loops; bending the strip into circular form with the U-shaped sections facing outwardly in thefinished ring and the loops extending radially outwardly between the upper and lower walls of the U-shaped sections.

3. The method of forming a piston ring consisting of the steps of; punching a strip of metal to provide a narrow central strip having laterally extended adjacent portions converging outwardly; bending the central strip between the laterally adjacent portions at right angles to the strip to form substantially open throated loops; bending the laterally adjacent portions upon the loops to provide U-shaped portions between the loops; substantially closing the throats of the loops and thereby-drawing the U-shaped portions of the strip closer together and; thereafter bending the ring into generally circular form with the adjacent edges of the laterally extended portions disposed on radial lines and minutely spaced.

4. The method of forming a piston ring from I,

a strip of metal comprising the steps of; punching apertures in said strip at spaced points; punching sets of apertures in rectangular arrangement around said first named apertures, the apertures in said sets on each side of the first named apertures being equally spaced from the strip edge; removing the metal within the spaces defined by lines running between those longitudinally aligned apertures of the adjacent sets and from these longitudinally aligned apertures to the adacent side edges of the strip to form a series of narrow central strips having substantially parallel edges; forming said narrow strips into loops; forming the wide portions of the strip into U- shaped segments opening outwardly in the finished ring and including as their inner walls in each instance a portion of the metal having one of the first named apertures therein and; bending the strip into circular form with the loops and U-shaped segments projected radially outwardly.

5. The method of forming a piston ring from a strip of metalcomprising the steps of punching sets of apertures in said strip in spaced relationship to delineate pairs of spaced notches in corresponding position on the two sides of the strip, each pair of corresponding notches being separated laterally by a narrow central strip; removing the metal from the notch portions so defined; bending the interior strips at right angles to the main strip to form open throated loops, bending the wide portions of the strip between the notches into U-shaped segments overlying the loops; compressing the strip lineally to close the throats of the loops and into close juxtaposition and; thereafter bending the strip into circular form with the loops and U-shaped segments projected radially outwardly.

- VICTOR F. ZAHODIAKIN.

to bring the U-shaped segments

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