US1881214A - Resilient piston - Google Patents

Description

Oct. 4, 1932. c. MELIDONI REsiLIENT PISTON Filed Dec. 21. 1927 2 Sheets-Sheet l v lNVENTOR g OA J TVV 77/VE MEL/00A ATTORNEY Oct. 4, 1932. c. MELIDONI RESILIENT PISTCN Filed Dec. 21. 1927 2 Sheets-Sheet 2 INVENTOR gONS WW5 MEL/00A 6 AT"TORNEY Patented Oct. 4, 1932 PATENT OFFICE CONSTANTINE MELIDONI, OF NEW YORK, 11'. Y.

BESILIEN'I. PISTON Application filed December 21, 1927. Serial No. 241,637.

This invention relates to pistons used for internal combustion engines and all kinds of engines in general, and the primary object of this invention is to provide a piston construction having skirt sections which are extremely resilient in a radial direction so as to conform itself to the cylinder walls regardless of their worn or tapered condition and which will operate without clearance space between these sections and the cylinder wall and thereby prevent piston slap.

Another object of this invention is to provide a piston having in two opposite sides of the piston skirt a series of longitudinal slots which terminate alternately at lateral slots Within the piston skirt thus forming resilient sections which are over-cylinder-size. When these resilient sections of the piston are compressed they react and exert an outward pressure against the cylinder wall thereby centering and supporting the piston within the cylinder.

Another object of this invention is to provide a piston with resilient sections, having a wear-compensating expanding action in order to maintain contact with the cylinder wall at all times regardless of wear and which can be periodically restored to their original operating diameter.

Another object of this invention is to produce a resilient piston having therein two oppositely placed series of parallel and substantially longitudinal slots which are cut through the piston from the outer to the inner circumferences and which will also have a solid head and a solid lower skirt section so that this resilient piston will present the appearance of solidity of the pistons in general use at present.

It is well known among those skilled in the internal combustion engine piston art that as a piston approaches each end of the stroke there is a force exerted which tends to move the piston laterally, resulting in a tendency to vibrate and cause piston slap. Attempts to counteract this piston slap and the noisy annoying clanking sounds have so far met with results which were not of a permanent nature. It has been customary to split the piston skirt by a substantially longitudinal slot which extended from the bottom edge of the skirt to a lateral slot below the lower ring groove. lVhen this type of piston is made over-cylinder-size and compressed so as to enter the cylinder, the center line of the piston bosses is thrown out of line and makes it impossible for the piston circumference to assume the contour of a perfect circle. Pistons of such construction wear out the same as the ordinary solid pistons do and have a limited life and do not fully meet the demand of the automotive industry for a replacement piston having extreme resilient properties and the service life of which shall at the same time be periodically restorable.

The problem consists in building a piston for an internal combustion engine with sections of the skirt made resilient and larger than the cylinder diameter and which could be compressed when entering the cylinder so that the piston skirt would fit tightly and the resilient sections of the piston would operate without the usual clearance of one onethousandth of an inch per inch of piston diameter.

The solution of this problem is rendered diflicult by reason of the high temperature in an internal combustion engine and the distortion of the cylinder by the expansion of the upper end of the cylinder under the heat so that the cylinder becomes an inverted frustum of a cone rather than a cylinder and that the piston when used under such operating conditions must be free to follow the tapering cylinder walls with each stroke of the piston. The skirt of the piston must be able to open up when the large diameter is reached and to close when the small diameter is reached and be subjected to an alternate outward and inward breathing action for each stroke of the piston. A piston structure that will meet these conditions must contain surfaces resiliently engageable with the cylinder wall at all times and regardless of the expansion or contraction of the working parts due to temperature changes.

In solving this problem I endeavored to combine these features in a piston of prac tical type having the above noted and desirable characteristics embodied in a simple structure.

'ith the above objects in "low the invention will be hereinafter more particularly described. and the combination and arrangement of parts will be shown in the accompanying drawings and pointed out in the claims which form part of this specification. It being understood that various changes in the form, proportion, size and minor details of construction within the scope of the claims, may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

Reference will now be had to the drawings, wherein like numerals of reference designate corresponding parts throughout the several views, in which:

Figure 1 is a front elevation of a resilient piston constructed in accordance with this invention.

Figure 2 is a bottom view of the piston.

Figure 3 is a view of a corrugated semicircular spring.

Figure 4 is a vertical section of the piston, the section being taken as on line wm in Figure 2.

Figure 5 is a section of the piston, the section being taken as on line 7 -g in Figure 4.

As shown in Figure 1, the piston illustrating this invention has the appearance of the usual stock piston. the skirt 1 of which has been provided with a plurality of longitudinal slots extending from the outer to the inner circumference of the piston.

As best shown in Figure 5, these slots 2, 3, 4, 5 and G, 7, 8, are located at a point diametrically perpendicular to the centre line of the wrist pin hole 9. A similar set of slots is located at the opposite point of the circumference. As best shown in Figure 4, there is a laterally cut slot 13 through the skirt on the cylindrical surface below the lower ring groove 12. Another lateral slot 14 is located in the same plane on the opposite side of the piston circumference. There are also provided two similar slots 15 and 16 which are located at the lower end of the piston skirt. These through slots are spaced in parallel planes within the piston skirt and form between them a plurality of spring bars which are integral with each other and with the skirt. The four slots 13, 15 and 14, 16 separate the spring bars between them respectively into independent resilient sections 10 and 11. The curved outer surfaces of these resilient sections are free to assume the contour of a larger circumference upon the application of a pressure from within the piston outwardly and against the spring bars. The slots in section 10 are located opposite the corresponding slots-of section 11.

As best shown in Fig. 2, the interior of the piston is provided with two semi-circular ring sections 23 and 24 to form open semicircular channels 25 and 26 between these ring sections and the skirt. There are also provided two corrugated semi-circular springs 27 which seat within the semi-circular channels 25 and 26 and press outwardly against and re-enforce the spring bars of the two opposed resilient sections 10 and 11 and hold the bars firmly .in place against the cylinder wall, thus moulding the resilient skirt sections and forcing them to assume the contour of the slightly larger size circle of the cylinder walls. The corrugations'of the springs have the effect of centering the piston within the larger size circle of the rissilient sections, thus preventing piston s ap.

As best shown in Fig. 4, the semi-circular ring sections 23 and 24 are in the same plane as the centre line of the bosses and are preferably placed at the middle of the longitudinal dimension of the spring bars. The width of the corrugated springs is preferably onequarter of an inch and the semi-circular ring sections are preferably provided with a onequarter inch wide annular groove 28 at their outer circumferential faces, so as to allow the springs to seat therein and prevent them from falling out when subjected to vibration. The annular grooves preferably taper at their lower edges so as to facilitate the removal of the springs. In addition to the grooves 28, there is a recess 29 at each end of the open semi-circular channels and these serve as a seat for each end of the spring 27. The spring bars are integral with multiple unit of bars which are capable of radial compression and expansion without distorting the lateral planes or the continuity of any of the surfaces where the spring bars join the solid skirt and this arrangement prevents buckling and crystallization.

The resilient sections 10 and 11 are preferably formed originally of a diameter greater than that of the cylinder and the remaining piston surfaces between these sections are relieved or ground down to cylinder size. The two resilient sections are then compressed sutficiently to permit the entrance of the piston into the cylinder. However, as best shown in Fig. 4 the complete piston including the resilient sections 10 and 11, the head 30 and a circumferentially intact section 31 'at the lower end of the piston skirt may be originally of cylinder size throughout and the springs 27 inserted within the piston skirt to exert an outward pressure against the resilient sections thereby forcing them to expand to a slightly larger diameter than the original piston. The resilient sections are shown in Fig. 2, in an exaggerted oversize position. Under actual operating conditions, the oversize is of so small a nature as to be hardly noticeable.

Particular attention is stressed to the fact that under all operating conditions in the each other and form a cylinder the resilient sections 10 and 11 maintain their over-eylinder-size while the rest of the piston is about three thousandths of an inch under-cyliiider-size. The operating diameter of the two resilient sections of this piston being larger than that of the cylinder for which it is to be used, a predetermined pressure is developed between the two resilient sections and the wall of the cylinder, and this pressure is variable and is limited so as to permit the reciprocating movement of the piston in the cylinder under working conditions without any scoring or seizing action and without any undue wear of the working parts. \Vhen the bearing sur- I faces of the two resilient sections 10 and 11 are finally worn down the springs 27 are inserted inside the two semi-circular channels 25 and 26. These springs press out the resilbe reversed and there will then be four longitudinal slots opening into the lower lateral slots 15 and 16.

In operation when the resilient sections 10 and 11 are compressed and the metal is brought under tension, there is a reaction and a tendency to expand to their original diameter and when the piston is inserted in an outof-round cylinder each section yields and conforms itself to the shape of the walls in badly worn cylinders where a perfect circle piston would be absolutely useless. The resilient sections absorb the side-thrust which ordinarily causes side-slap or piston-slap.

It is to be noted that while in Figures 1 to 5, inclusive, the illustrations show this pistion as equipped with means for re-enforcing and restoring the spring bars, the piston may if desired be formed without the semicircular ring sections 23 and 24 and the resilient sections may be made over-cylinder-size and thus function without the re-enforcing effect of the springs 27.

It is also to be noted that the corrugated spring 27 is so formed that the circumferences of the outer and inner corrugations are concentric, that the corrugations are wider at the outer circumference 32 and narrower at the inner circumference 33; also that both ends of the spring 34, 34, are reversely curved so as to form means for locking both ends of the spring in the recesses 29, 29.

When this slotted piston reaches the lower end of the cylinder the oil thrown into the skirt of the piston passes through the slots pressure.

and'lubricates the cylinder wall. This piston structure 'islthu s adapted to convey oil between the inner .andouter circumferences of the piston andtakes care of excessive wall Pistons constructed according to the subject matter of this invention may. be made either of cast irono r of aluminum alloys or of any other metal and are adapted for use in newgor reground icylinders and for worn cylinders. I The, 'pistojislt nay bev used extensively for replacement"purposes on automobile iii'oto rs,- and,;inay ;liave.to operate in worn out cylinders havijng tapering walls generally smaller in dia nietler at the lower end of the cylinder. :Wheh th e'pistonrea ches the smaller diametei fof the cylinder thetwo rt silient sections gof the piston i 2 compressed and theinetalrec edes internally within the piston. lVhen the la'r ia-ineten is re ached the resilient sections-expand toj't'he'larger diameter and the operationhis in a :sort of breathing action l'i i I have demonstrated fby actiial practice that a piston embodying featureswof this invention and of oyer-cylinder-si zegcan operate successfully: under fi'v'ofrkingfl 'conditions and that it fitsfan d con w itself immediately to any oncliti i Iii a ildiout-ofround cylinder withot t iiy distortion of the bosses or of the spriii ba r s' i It is" thus .readily' see Ythat the-re has been provided a resilient lf fconfo rining piston with a wear-compensatingexpanding action;

the bearing 'surfac e'so periodi- Cally restored. ta'th eirpjri' iah .ope'rating diameter, a'piston having anxtraordinary service life, a piston which will eliminate the annoyance caused by piston slap and which will have a substantially solid appearance and the cost of which is within the limits of commercial requirements.

Having thus described my invention I claim as new and desire to secure by Letters Patent:

1. A resilient single piece piston comprising a head having piston ring grooves upon its periphery and a skirt provided with wrist pin bosses and being integrally connected with the head between said bosses, the skirt being provided with two oppositely disposed series of parallel through slots longitudinally placed and terminated within the piston by two lateral through slots.

2. A resilient single piece piston comprising a head having piston ring grooves upon its periphery and a skirt provided with wrist pin bosses and being integrally connected with the head between said bosses, the skirt being provided with two oppositely disposed series of parallel through slots longitudinally placed and terminated within the piston by lateral through slots, forming two resilient bearing sections of over-cylinder-size, whereby when the piston is inserted in the cylinder Ill) the over-eylinder-size sections are under tension and bear against the cylinder wall with a limited radial 'pressuresnflicient to suspend the piston within the cylinder.

3. A resilient piston comprising; a head having piston ring grooves upon periphery. a skirt having a eireulnferentially intact lower end section. two pair of lateral through slots in spaced planes between the head and the lower skirt section, two radially resilient sections between the lateral slots and two semi -eircnlar ring-sections integral with the wrist pin bosses, said semi-c'ircnlar ring-sections being located snbstanti alh' midway between the lateralslots, 4. The conibination of a resilient piston provided with two slotted skirt sections respectively comprising a plurality of spring bars integral with the skirt and with each other, two semi-circularring sections integral with the wrist pin bosses. forniing two semicircular channels between the ring sections and the skirt and twoeorrugated semi-circular springs, seating within the semi-circular channels to yieldably expand the two slotted sections.

5. A piston coinprisinga tubular body provided with oppositely disposed resilient sections adapted to be independently expanded to form concentric parallel semi-circles.

6 A piston eomprisingva tubular body provided with oppositely disposed resilient sections adapted to be independently expanded to form coneentrioimrallel semi-circles and resilient nea'nsdisposed'iiisideof the body for expanding the resilient sections.

C O'NSTANTINE iMELIDONI.

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