US1908718A - Piston and ring assembly - Google Patents

Description

May 16, 1933.

J. WlLLiAMS PISTON AND RING ASSEMBLY 3 Sheets-Sheet 1 Filed June 29. 1929 avwewtoz (Janitor: William y 6, 933- -J.W1LL!AMS 1,968,718

PISTON AND RING ASSEMBLY Filed June 29, 1929 3 Sheets-Sheet 2 y 1933. J. WILLIAMS I 1,908,718

PISTON AND RING ASSEMBLY Filed June 29.. 1929 3 Sheets-Sheet 3 30 H l 1 a1 E T j i Z3 42 l i z I j v v j 3 f2 4/ Z 2 anocul o'o Ju dd on 177/! z'anur 3 w attuned:

45 Figure 8 is a transverse sectionalview on Patented May 16, 1933 UNITED STATES PATENT oFFIcEJ PISTGN AIQ'D RING ASSEMBLY Application filed June-29, 1929. Serial No. 374,785.

This invention relates to an improved piston and ring assembly and seeks, among other objects, to provide a construction wherein the piston will be solidly guided in its reciprocating movement.

A further object of the invention is to provide an assembly wherein the piston will, when in operation, be forced laterally against the cylinder wall to be at all times m guided and sustained by said wall to thus prevent rocking movement of the piston and piston slap.

A still further object of the invention is to provide an assembly wherein the lateral pressure on the piston will be increased-with the application of heat and the expansion of the piston.

And the invention seeks, as a still further object, to provide an assembly wherein undue friction will be overcome.

Other objects of the invention'not-specifically stated in the foregoing will appear during the course of the following description.

In the drawings,

Figure 1 is a; vertical sectional view showing my'improved assembly in position in a conventional engine cylinder,

Figure2 is a plan view showing the cocentricity of the upper end portion of the piston, the cylinder being shown in section,

Figure 3 is a transverse sectional view particularly showing one of the piston rings and thetensioning element used in connection therewith,

' Figure 4 is, a detail elevation showing the split in the skirt of the piston,

Figure '5 is an elevation showing a differcut embodiment of the invention,

Figure 6 is a transverse sectional view on the line 6-6 of Figure 5,

Figure 7 is an elevation showing a further embodiment, T

the line 88 of Figure 7, Figure 9 is a vertical sectional view showing a still further embodiment of the invention Figure 10 is a vertical sectional view showa further embodiment of the invention,

an I

Figure 11' is a transverse sectional view showing the construction illustrated in Figure 10.

Referring now more particularly to Figures 1 to 4: inclusive of the drawings, the piston of the present invention includes a head 10 from which depends a resilient skirt 11 preferably split at one side as indicated at 12. A conventional wrist pin is indicated at 13 and the wrist pin bosses of the piston at 14. For convenience, I have shown the piston in position in a conventional engine cylinder 15.

As 'most clearly shown in Figures 1 and 2 of the drawings, the piston is formed at one side with an external longitudinally straight face 16, which extends throughout the length of the piston and is ofthe same radius as the internal radius of the cylinder so that said face thus fits throughout its entire area flat against the cylinder wall. For convenience, the face 16 will be termed the straight side of the piston. At the upper end portion of the piston, the remainder of the outer circumference thereof, or that portion of the piston not occupied by the straight side 16,. is eccentric, being of considerably less radius than the internal radius of the cylinder. However, this eccentricity of the upper end portion of the piston terminates near the lower end of the piston and near its lower end, the skirt is formed with an area A concentric to the axis of the piston and to the cylinder. This concentric area A is substantially cylinder size and coacts with the cylinder wall for firmly centering and supporting the piston at its lower end. In the present instance, I have shown the straight face 16 of the piston in a plane at right angles to the plane of the Wrist pin 13 at the high pressure side of the piston.

Formed in the head of the piston is a plurality of ring grooves and removably fitting therein are resilient rings 17 which may .be of ordinary construction. Freely fitting in the grooves behind the rings, as seen in Figure 3,.are split resilient corrugated ex; panders or tensioning elements 18, pressing cally opposite side of the piston. Thus, the

expanslon of the piston will tend to crowd I the pistonrings into the ring grooves at of the expanders 18 automatically.

the eccentric side of the piston to thus increase the tension on the adjacent porltxions s a result the elements 18 will be caused to force the piston laterally and yieldably hold the straight face 16 thereof constantly in contact with the cylinder wall. Thus, since the face 16 isof the same radius as the internal radius of the cylinder, said face will coact with the cylinder wall for solidly guiding the piston in its reciprocating movement. Consequently, rocking movement of the piston with resultant piston slap will be efi'ectually prevented. At the same time, undue mechanical friction is avoided by reason of the fact that the area of the piston in contact with the cylinder is relatively large, as compared with the pressure exerted by the rings on the cylinder wall.

In Figures 5 and 6 of the drawings, I have illustrated a slightly different embodiment of the invention wherein the piston is indicated at 19 and a cylinder at 20. The piston 19 is substantially thesame in construction as the piston of the prior embodiment with the exception that the straight face of the piston 19 is disposed in a plane with the wrist pin bosses of the piston while the eccentric side of the piston extends clear to the bottom thereof, the concentric area A as illustrated in the prior embodiment being eliminated. The head of the piston 19 carries a plurality of rings 21 while the skirt is equipped with a similar ring 22. These rings are all like the rings 17 previously described and disposed behind said rings are tensioning elements 23 like the elements 18.

Thus, in this embodiment of the invention the tensioning elements behind the rings 21 will, when the piston expands, force the upper end of the piston laterally while the tensioning element behind the ring 22 will force the lower end of the piston laterally. The

straight face of the piston will thus be firmly held in contact with the cylinder wall to prevent rocking movement of the piston and piston slap will be effectually prevented.

In Figures 7 and 8 of the drawmgs, I have illustrated astill further embodiment of the invention wherein the piston is indicated at 23 and a cylinder at 24. The piston 23 is identical with the piston first described with the exception that the straight face of the piston lies in a plane with the wrist pin bosses. The head of the piston carries a pluralit of rings 25 likev the rings 17, and dispose in the ring grooves behind the rings, as seen in Figure 8,- are arcuate resilient tensioning elements 26 which are preferably corrugated. Securin said elements medially to the bottom wa ls of the rin grooves are pins 27. The elements 26 are coated at the side of the piston opposite the straight face thereof and, as will be appreciated, will normally force the piston laterally and hold the stralght face thereof in contact with the cylinder wall. Furthermore, as the piston expands, the tension on the elements 26 will, as will be understood in view of the foregoing description, be increased for increasgng the lateral force on the piston tending to hold the straight face thereof in contact with the cylinder wall. Rocking of the piston will thus be elfectually prevented.

In Figure 9 of the drawings, I have illustrated a further embodiment of the invention wherein the piston is indicated at 28 and a cylinder at 29. The piston 28 is identical with the piston first described with the exception that the straight face of the piston 28 is located in a plane with the wrist pin bosses of the piston. At its upper end the piston 28 carries a plurality of rings 30 like the rings 17 and disposed behind the rings 30 are tensioning elements 31 like the tensioning elements 18. In this instance, I have shown a conventional wrist pin M32 and a coacting connecting rod at 33. Surrounding the wrist pin boss located at the straight side of the piston is a spring 34 one end of which bears against the piston wall while the other end of said spring bears a ainst the adjacent side of the top bearing 0 the connecting rod. Thus, the spring will force the piston laterally and constantly hold the straight face thereof in contact with the cylinder wall. I

In Figures 10 and 11 of the drawings, I have illustrated a still further embodiment of the invention wherein the piston is indicated at 35 and a cylinder at 36. The piston 35 is substantially identical with the piston 19 with the exception that the straight face of the piston 35 is located in a plane at right angles to the wrist pin bosses while at a point 4 diametrically opposite the straight face of the piston, the piston skirt is provided with an inwardly directed radial socket 39 located slightly below the axial plane of the wrist pin bosses. At its upper end the plston 35 carries a plurality of rings 38 like the rlngs 17 and disposed behind the rings 38 are tensioning elements 39 like the elements 18. Adjacent the mouth of the socket 37, the skirt is provided witli a recess 40 and freely received in said recess is an arcuate shoe 41 provided medially with a stem 42 which slidably fits in said socket. The shoe is curved to conform to the curvature of the cylinder wall so as to seat flat thereagainst and confined in the socket to act against the stem 42 is a spring 43 urging the shoe against the cylinder wall. Thus, the shoe and spring will function to force the piston laterally and hold the straight face thereof constantly in contact with the cylinder wall so that rocking movement of the piston and consequent piston slap will be prevented.

Having thus described the invention, I claim:

1. The combination with a cylinder, of a piston movable therein and rovided with a straight side fitting the cy inder wall, the piston being eccentric at its opposite side and being provided at its lower end with a concentric slotted skirt inte al with the piston and substantially cylin or size and yieldably fitting the cylinder wall for centering and sustaining thelower end of the piston, and piston rings carried by the upper end portionof the piston to coact with the cylinder at the eccentric side of the piston and operable for exerting a lateral force on the piston holding the straight side thereof in contact with the cylinder wall.

2. The combination with a cylinder, of a piston movable therein and provided with a lower concentric integral skirt and an upper eccentric end having a straight side fitting the cylinder wall flush with the skirt, the piston being formed with a ring groove of uniform depth in said upper end, a ring fittlng in said groove, and a tensioning element urging the ring to coact with the cylinder wall opposite the straight side of the piston for exerting a lateral force on the iston and holding the straight side thereo in contact with the cylinder wall.

3. The combination with a cylinder, of a piston movable therein and provided with a straight side and opposite eccentric side, the piston having a lower integral concentric skirt centered in the cylinder and being formed with a rin groove extending transversely across said straight side and said eccentric side a ring fitting in said groove, and a tensiomng element tending to expand the ring to ooact with the cylinder, whereby expansion or" the piston will compress said element at the eccentric side of the piston and cause said element to exert a lateral force on the piston holding the straight side thereof in contact with the cylinder wall.

4. The combination with a cylinder, of a piston having. an integral concentric skirt fitting the cylinder wail, said piston being-eccentric above the skirt to provide a straight side for contact with the cylinder, and piston rings carried by the eccentric portion of the cylinder and adapted to coact with the cylinder at the eccentric side of the piston for maintaining said straight side of the piston in contact with the cylinder wall.

5. The combination with a cylinder, of a piston having an eccentric upper and providing a straight side of substantially the same radius as the cylinder and fitting the cylinder wall and providing an opposite side of less radius than the cylinder and spaced from the cylinder wall, an integral skirt below said eccentric end of the same radius as the cylinder and forming a continuation of said straight wall, and yielding piston rings carried by said eccentric upper end of'the piston and compressed by expansion of the piston for forcin the piston laterally in the cylinder and hol ing the straight side thereof in contact with the cylinder wall.

6. The combination with a cylinder, of a piston movable therein and provided near its lower end with a concentric integral skirt substantially cylinder size and forming the lower end of the piston, the upper end of the piston being eccentrically disd relativel to the skirt to provide a straight wall flus with the skirt and an eccentric wall of less radius than the radius of the skirt, piston rings carried in grooves of uniform depth formed in said eccentric upper end portion of the piston, said rings being adapted to coact with the cylinder wall at the eccentric side of the piston and exerting lateral force on the piston to hold the straight side of the piston in contact with the cylinder wall.

7. The combination with a cylinder, of a piston having an upper end provided with a straight side fitting the cylinder wall and an eccentric side spaced from the cylinder wall, the piston being formed at its lower end with an integral shirt eccentrically disposed with respect to the upper end of the piston adapted to lit the cylinder wall throughout for centering the piston in the cylinder, said shrt and said eccentric side being slotted to provide resiliency in the piston, and piston rings carried by the upper end of the piston in grooves of uniform depth-and adapted to coact with the cylinder wall -at the side of the piston opposite the straight side thereof and exert a lateral force on the piston to hold the straight side of the piston in contact with the cylinder wall. 7

8. A piston comprising a head and trunk, the trunk beingsubstantially cylindrical and having one segmental portion of its sides 0 posits the wrist pin axis curved on a slight y csser degree of curvature than the remaining portion oi said sides, the outer surface of said remaining portion being of approximately the same radius of curvature as the interior of the cylinder in connection with which the piston is designed to be used.

in testimony whereof I ax my signature.

JUDSGN 1 IAMS. [L- 5.]

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