US3915141A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Built up engine piston
Assignee: MAN AG
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Filing: 1974-01-23
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Granted: 1975-10-28
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Expires: 1994-01-23
Abstract
Abstract A piston, particularly for use in heavy diesel motors, is built up of a piston head, an intermediate piece and a lower piston body piece. The piston head has internal annular ridges extending down to a plane joint surface and of a minimum height sufficient to accommodate tapped holes for the screws that fasten the middle piece to the piston head. The middle piece has a disc or annular base with a lower annular mounting surface and upwardly extending annular webs that meet the ridges of the piston head. The webs are disposed on conical surfaces that have their vertices on the piston axis, the outermost one having a vertex below the middle piece and the other having its vertex above. Additional webs and ridges may be used for very wide pistons. The bottom piece has a tapered annular upward extension meeting the base of the middle piece beneath the supporting webs and provision for screwing the bottom and middle piece together. An upper skirt forms part of the piston head and carries grooves for piston rings. An upward projection of the lower skirt serves to center the upper skirt. Efficient transmission of forces to the piston rod bearing with relatively light component parts and even distribution of thermal stresses is obtained as well as freedom from loosening the structure under suction.
Inventors
- 👤 Adolf Ottl
- 👤 Ernst Pfleiderer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:22
CPC Classifications
F; F02; F02B; F02B23/00; F02B23/02; F02B23/06; F02B23/0696; F02F; F02F3/00; F02F3/0015; F02F3/0023; F02F3/16; F02F3/20; F02F3/22; F02B75/00; F02B75/02; F02B2075/022; F02B2075/027; F02B3/00; F02B3/06; F05; F05C; F05C2201/00; F05C2201/02; F05C2201/021; F05C2201/04; F05C2201/0433; F05C2201/0448; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49229; Y10T29/49249; Y10T29/49256
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
150 words
In a built up engine piston comprising a piston head portion and a lower body portion demountably held together in mutually supporting relation by machine screws, the improvement in which: the piston head portion has a relatively thin piston face (4); at least two internal annular ridges (7, 8) at respectively different radial distances from the piston axis (A - A) and having a common center located on the piston axis, are provided on said piston head portion extending downwardly from said piston face to flat annular ridge summit surfaces; said annular ridges support said piston head portion on said lower body portion, said annular ridges are tapped to receive the threads of said screws (16, 17), and said body portion (2) comprises a core portion (24) surrounding the piston rod bearing (25) and support means (26, 12, 13) extending from said core portion towards said annular ridges (7, 8),
Claim 2
Dependent Claim
150 words
In a built up engine piston comprising a piston head portion and a lower body portion demountably held together in mutually supporting relation by machine screws, the improvement in which: the piston head portion has a relatively thin piston face (4); at least two internal annular ridges (7, 8) at respectively different radial distances from the piston axis (A - A) and having a common center located on the piston axis, are provided on said piston head portion extending downwardly from said piston face to flat annular ridge summit surfaces; said annular ridges support said piston head portion on said lower body portion, said annular ridges are tapped to receive the threads of said screws (16, 17), and said body portion (2) comprises a core portion (24) surrounding the piston rod bearing (25) and support means (26, 12, 13) extending from said core portion towards said annular ridges (7, 8),
Claim 3
Dependent Claim
56 words
Improvement in an engine piston as defined in claim 1 in which the height of said ridges (7, 8) in the direction of said piston axis (A - A) corresponds substantially to the necessary depth for the threads of said screws (16, 17) and in which said annular ridge summit surfaces lie in the same plane.
Claim 4
Dependent Claim
20 words
Improvement in an engine piston as defined in claim 1 in which said piston head portion is made of steel.
Claim 5
Dependent Claim
21 words
Improvement in an engine piston as defined in claim 1 in which said piston head portion is made of cast steel.
Claim 6
Dependent Claim
47 words
Improvement in an engine piston as defined in claim 1 in which said piston head portion (1) is made in one piece with an upper piston skirt (5) provided with grooves (6) for seating piston rings and with projections (29) for centering on said lower body portion.
Claim 7
Dependent Claim
98 words
Improvement in an engine piston as defined in claim 1 in which said lower body portion is composed of a piston middle portion (3) and a piston bottom portion (2) demountably connected together by screws (30) located at a radial distance from said piston axis (A - A) greater than the corresponding radial dimension of said piston rod bearing (25), said piston bottom portion including said core portion of said piston body Portion and an annular support member (26) of generally frusto-conical configuration with its widest part situated where said piston bottom portion meets said piston middle portion.
Claim 8
Dependent Claim
35 words
Improvement in an engine piston as defined in claim 6 in which said piston bottom portion (2) is made of a material selected from the group consisting of aluminum and of spheroidally graphitic cast iron.
Claim 9
Dependent Claim
31 words
Improvement in an engine piston as defined in claim 6 in which said piston middle portion (3) is made of a material having a larger elasticity modulus than gray cast iron.
Claim 10
Dependent Claim
48 words
Improvement in an engine piston as defined in claim 6 in which all of said screws (16, 17, 30) are in the form of necked-down screws and in which spacing bushing means (20, 21, 34) for guiding said screws are provided in the neighborhood of the screw heads.
Claim 11
Dependent Claim
34 words
Improvement in an engine piston as defined in claim 6 in which said screws (16, 17) securing said piston head portion (1) fasten said piston head portion (1) to said piston middle portion (3).
Claim 12
Dependent Claim
69 words
Improvement in an engine piston as defined in claim 3 in which said piston middle portion (3) has a base portion of disk or flat ring shape facing said support member of piston lower portion (2) and is provided with extending annular support webs (12, 13) extending from the juncture with said support member (26) respectively to junctures with said ridges (7, 8) of said piston head portion (1).
Claim 13
Dependent Claim
35 words
Improvement in an engine piston as defined in claim 11 in which said piston bottom portion (2) comprises a piston skirt member (28), as well as said core portion (24) and said support member (26).
Claim 14
Dependent Claim
41 words
Improvement in an engine piston as defined in claim 11 in which said support webs (12, 13) are partly cut away in the neighborhood of each of the screws securing said piston head portion (1) to the remainder of the piston.
Claim 15
Dependent Claim
86 words
Improvement in an engine piston as defined in claim 13 in which said screws (16, 17) securing said piston head portion (1) are necked-down screws and in which the ratio of the cross section of the shaft of each screw (16, 17) to that of the bore where they pass through the joint surface between said piston head portion (1) and said piston middle portion (3) is such as to allow a small radial movement of said piston head portion relative to said piston middle portion.
Claim 16
Dependent Claim
44 words
Improvement in an engine piston as defined in claim 13 in which said support webs (12, 13) are both of generally frusto-conical shape and disposed in each case about the surface of a cone having its vertex on said piston axis (A - A).
Claim 17
Dependent Claim
76 words
Improvement in an engine piston as defined in claim 15 in which that one of said support webs (13) which connects with that one of said ridges (8) of said piston head portion (1) having the greater radial distance from said piston axis (A - A) is disposed on a conical surface of which the vertex is downwardly directed and said conical surface passes through said support member (26) and through said piston rod bearing (25).
Claim 18
Dependent Claim
32 words
Improvement in an engine piston as defined in claim 15 in which another of said support webs (12) is disposed on a conical surface having its vertex above the piston face (4).
References Cited (Backward Citations)
US1089823A
Cited
US3520234A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |