Metal working – Plural diverse manufacturing apparatus including means for... – Separate tool stations for selective or successive operation...
Reexamination Certificate
2000-05-02
2001-09-18
Briggs, William (Department: 3722)
Metal working
Plural diverse manufacturing apparatus including means for...
Separate tool stations for selective or successive operation...
C029S564000
Reexamination Certificate
active
06289574
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a forged connecting rod, in particular of an internal combustion engine, comprising a body, a connecting rod small end and a connecting rod big end forming two connecting rod small end and connecting rod big end bearings for respectively receiving a piston pin and a crankpin, said connecting rod comprising two half connecting rods which are substantially symmetrical relative to a longitudinal median plane of the connecting rod, said plane containing the longitudinal axis of the connecting rod, the joint surface of the half connecting rods being essentially contained in the median plane, said half connecting rods, each of which carries a connecting rod small end half bearing and a connecting rod big end half bearing, being interconnected by at least one immobilizing means positioned on each side of the connecting rod small end and big end.
A connecting rod is known which comprises a body, a connecting rod small end and a connecting rod big end forming cylindrical bearings for receiving, on one hand, a piston pin and, on the other hand, a crankpin. The connecting rod is constituted by two forged half connecting rods which are assembled together along a joint surface and locked to each other by immobilizing means. The two half connecting rods each comprise two half bearings and are substantially symmetrical relative to the longitudinal median plane of the connecting rod and the joint surface is essentially contained in said longitudinal median plane. At least one immobilizing element is located on the body of the connecting rod between the big end and the small end of the connecting rod.
This design of a forged connecting rod, formed by half connecting rods which are completely identical for reasons of industrialization and production by forging methods, makes it necessary to prevent any micro relative displacement of the half connecting rods which might produce a fretting phenomenon on the contacting surfaces. A complete immobilization can be achieved by means of centering screws, but this method involves difficulties of construction and production costs.
In order to prevent the displacement of one half connecting rod relative to the other, it is possible to envisage providing serrations, for example linear serrations or linear and crossed serrations. Now, linear serrations do not permit an assembly by superimposition of two half connecting rods without risk of an offset position of one half connecting rod relative to the other to the extent of a pitch or two pitches of the serrations.
Further, the linear serrations do not prevent the possibility of the displacement of one half connecting rod relative to the other in the longitudinal direction of the serrations.
SUMMARY OF THE INVENTION
An object of the invention is to provide a forged connecting rod, in particular of an internal combustion engine, which provides, by the superimposition of two half connecting rods which are matched and machined simultaneously, a locking of one half connecting rod relative to the other in the joint plane with no possibility of an offset or a displacement.
The invention provides a forged connecting rod which is characterized in that the immobilizing means further comprise serrations which are provided on the joint surface of the half connecting rods and fit into one another in a complementary manner, said serrations ensuring by their shape a locking against slip of the two half connecting rods in the joint plane, a locking against slip on the longitudinal axis of the connecting rod and along the axis of the crankpin and the piston pin simultaneously.
Other characteristics of the invention are:
the assembling means comprise serrations of curved shape.
the assembling means comprise serrations in the shape of arcs of a circle.
the assembling means comprise serrations in the shape of concentric arcs of a circle, the concavity of which is oriented in a single direction.
the assembling means comprise serrations the concavity of which is oriented along an axis coincident with the longitudinal axis of the connecting rod.
The invention also relates to a method for producing a connecting rod from as-forged rough half connecting rods, in which rough half connecting rods are placed on the periphery of a circular plate for the distribution of different successive machining operations, characterized in that it comprises:
placing and clamping the as-forged rough half connecting rods in pairs in diametrally opposed relation, the joint surface remaining free,
carrying out on each of the two half connecting rods a boring spotfacing and machine surfacing operation on the joint surface, the boring and spotfacing operations being intended for the mechanical assembly of said half connecting rods and the fixture of the half connecting rods on the plate,
producing on the machine surfaced joint surface of the two half connecting rods serrations which ensure by their shape after the assembly of the two half connecting rods in facing relation to each other, a locking against slip in the joint plane, said locking occurring in particular along the longitudinal axis of the connecting rod and along the axis of the crankpin or the piston pin simultaneously.
machine surfacing parallel faces defining the thickness of the connecting rod big end or small end. assembling the two half connecting rods by rotation through 180° of one half connecting rod relative to an axis of rotation parallel to the plane of the circular plate, the serrations fitting into one another in a complementary manner.
machining bores forming connecting rod big end and small end bearings.
The invention also relates to a device for producing a connecting rod by means of the aforementioned method from as-forged rough half connecting rods, said device comprising a circular plate for the distribution of different successive machining operations, characterized in that it comprises in diametrally opposed relation the following machining stations having the same function:
a clamp for the as-forged rough half connecting rods,
a station for the boring spotfacing and machine surfacing the joint surface,
a fixture station,
a serrating station for machining the serrations, a station for machine surfacing parallel faces defining the thickness of the connecting rod big end or small end,
a rotary assembling station for assembling two half connecting rods for positioning two half connecting rods in facing relation, the serrations fitting into one another in a complementary manner,
a station for machining bores which form connecting rod big end and small end bearings.
REFERENCES:
patent: 3818577 (1974-06-01), Bailey et al.
patent: 4936163 (1990-06-01), Hoag et al.
patent: 5353500 (1994-10-01), Hoag et al.
patent: 5536089 (1996-07-01), Weber et al.
patent: 5655296 (1997-08-01), Ravenshorst et al.
patent: 6076426 (2000-06-01), Genouille
patent: 1198613 (1965-08-01), None
patent: 47-23243 (1972-06-01), None
patent: WO 86/04122 (1986-07-01), None
Ascometal
Briggs William
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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