US1590616A

US1590616A - Flexible skirt piston

Info

Publication number: US1590616A
Application number: US46445A
Authority: US
Inventors: Lewis R Davis
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-07-27
Filing date: 1925-07-27
Publication date: 1926-06-29
Anticipated expiration: 1943-06-29

Description

L. R. DAVIS FLEXIBLE SKIRT PISTON Filed July 27, 19.25

June 29 192 1,590,616

-: xix

5 Lew/s i 0.410s

W 35 M a Patented June 29, 1 926.

UNITED STATES LEWIS R. ZDA VIS, OF SAN rmcrsoo, camnonnm FLEXIBLE sxmr PISTON.

Application filed July 27, 1925. Serial No. 46,445.

This invention relates to pistons of the split skirt type especially those adaptable forinternal explosive engines, and the objects of the invention are to provide a split 5 skirt piston construction which is easily produced byordinary molding or die casting processes which will effect a perfect. fit to the cylinder to compensate for considerable wear thereof, and which will greatly reduce" 1 the oil pumping tendency common to such pistons. Other advantages of my construction will appear in the following description. The drawings accompanying this specification show the preferred embodiment of the invention, it being understood that such minor changes as fall withinthe spirit thereof are intended to be covered in the claims hereto appended.

Figure 1 of the drawing is an external view ofmy piston. I

Figure 2 is a vertical section through the center thereof.

Figure 3 is a transverse section of the piston as taken along the line 3-3 of Figure 2.

In 7 further detail mypiston comprises a head 1 cast with a cylindrical wall 2, and a pair of opposed bosses 3 adaptedv to take the wrist pin 4 of a connecting-rod 5.

The bosses 3 are rigidly braced to the wall and head by an integrally cast rib 6 extending across the under side of the head 1. The cylindrical Wall 2 is of reduced I diameter from its lower edge to a point 5 A above the bosses, and surrounding this reduced'portion is an outer flexible wall or split skirt 7.

1 This skirt p 7 is spaced from the reduced wall by an annular space 8 preferably l0 slightlylarger at the bottom as indicated in Figure'2, so that in die casting the core die may be easily pulled out. The skirt is cast integrally with the body of the iston, being connected thereto by a lug 9 ad jacent 5 which the skirt is slotted fromend to end after finishing as shown at 10.

The lug 9 and slot 10 may be vertical but I prefer to run them on a spiral, as indicated in Figure 1, so that theskirt in expanding, to compensate for cylinder wear,

will better preserve its rotundity.

The lug 9 may be of any desired proportions and located directlyat the point of slotting or spaced therefrom, or. if desired two lugs may be used andalso' two slots,

this all depending on the amount of flexibility desired in the particular piston.

In casting the piston and skirt the space 8 may terminate as indicated at 8' and the skirt is extended as indicated at 7' to connect integrallywith the piston body, so that it forms a firm unit for turning, grinding or boring for the wrist pin, etc., after which two oil ring grooves 11 are turnedin the upper end of the piston and finally a third groove 12 which penetrates the cored space '8 and separates the upper end of the skirt from the body of the piston.

The skirt is bored at 15 to clear the pin 4 so that the skirt will be freelto expand against the cylinder walls, and just below the bosses 3 a split expanding or bull ring 13 is seated in a very shallow groove 14 turned in the inner surface of .the skirt.

In using the iston the usual split rings are inserted in t e grooves 11 and 12 and a ring in the latter, it will be noted, will be supported between an upper wall formed on the body of the piston and the substantially free upper end of the skirt. This construction provides a flexible skirt supporting the lower ring and with a free annular passage 8 extending from the skirt and body ofthe piston o en'at almost the entire circum: ference of t e piston to the lower oil ring roove. Thus, the annular passageway 8 unctions to completely drain any surplus oil from the lower groove back into the crank case, and the reduced'diameter of the 1 piston body acts as a bafile wall to prevent oil being thrown into the passageway, and the bull ring positioned to almost, cover the lower end of the passageway prevents any oil being thrown u wardly, into the passage, thus insuring t atihe oil will not rise in in'urious amountabove the lower ring, and t e skirt itself beingsplit from end to end and spaced from the body of the piston acts like a very long ring almost independ ent of the body, thus effectually compensating for all wear of the walls.

1. A' piston chmprising a' head portio having a reduced lower end of annula cross-section throughout, the said reduced lower end, being bored at opposite points i above its lower edge to'provide wrist pin bosses, a split skirt surrounding the. said reduced lower end; portion and extending above the wrist pin bosses and a rib connectedto the reduced lower end portion and to the skirt for supporting the latter in spaced relation to the head and to the said lower end portion.

2. A piston comprising a head, a split skirt located belowthe head and aced therefrom, the said head having are nced lower end portion of annular cross-section extending into theupper end of the skirt and downwardly therethrough and spaced therefrom and operating to provide a battlefor intercepting lubricant entering upwardly through the lower end of the skirt and directing the lubricant inwardly and away from the adjacent intervening space, said reduced lower end portion having oppositely disposed wrist in bosses located below the upper end 0 the skirt, and a rib connected to the said lower end portion of the head and to the skirt and for sup orting the latter in s aced relation to the ead and to the said re uced end portion thereof.

3. A piston comprising a head, a split skirt located below the head and spaced therefrom, the said head having a reduced lower end portion of annular cross-section extending into the upper end of the skirt and downwardly therethrough and spaced therefrom and operating to provide a battle 'for intercepting lubricant entering upwardl through the lower end of theskirt and lrecting1 the lubricant inwardly and away from t e adjacent intervening space, said reduced lower end portion having oppositely disposedwrist pin bosses locatedbelow the upper end of the skirt, a rib connected to the said lower end portion of the head and to the skirt and for supporting the latter in spaced relation to the head-and to surrounding the lower part of the body portion and spaced therefrom, said sleeve being split from end to end along a spiral line and integrally connected to the lower part of the body portion by a cast spiral lug lying adjacent one edge of the s lit.

' LEWIS R. AVIS.