Metal working – Method of mechanical manufacture – Prime mover or fluid pump making
Reexamination Certificate
2002-11-15
2004-09-14
Bryant, David P. (Department: 3726)
Metal working
Method of mechanical manufacture
Prime mover or fluid pump making
C029S888042, C029S888049, C029S888050, C029S222000, C029S225000, C029S229000, C029S235000, C029S269000, C029S275000
Reexamination Certificate
active
06789313
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a hand tool for inserting an internal retainer ring, lock ring or snap ring in a piston-pin bore and other bores.
A large portion of pistons for crankshaft engines are made to utilize an internal snap ring, referred to as a lock ring, in each end of a piston-pin bore for preventing side travel of a piston pin. Pistons for aftermarket use are supplied separately from connecting rods and piston pins for which the piston pins are used to assemble them together. Conventional assembly for repair and rebuilding of engines is a long and tedious task. It is accomplished with general-purpose tools like screwdrivers, picks and pliers with which even experienced workers often mar and damage the pistons.
There is no known hand tool for inserting the lock ring quickly, conveniently and safely in a manner taught by this invention.
Examples of most-closely related known but different devices are described in the following patent documents:
U.S. Pat. No.
Inventor
Issue Date
2,357,139
Seme
Aug. 29, 1944
4,514,889
Ferlan, et al.
May 7, 1985
5,146,676
Cuba
Sep. 15, 1992
3,631,688
Quick
Jan. 4, 1972
6,389,667
Cook, et al.
May 21, 2002
5,794,984
Bartholomew
Aug. 18, 1998
3,030,700
Jensen
Apr. 24, 1962
6,113,306
Allert
Sep. 5, 2000
SUMMARY OF THE INVENTION
Objects of patentable novelty and utility taught by this invention are to provide a piston-pin lock-ring-insertion tool which:
decreases engine-assembly time for inserting lock rings in pistons from an hour or more to about one minute;
avoids marring of pistons with general-purpose tools now used for inserting; and decreases worker fatigue;
avoids occasional injury from use of the general-purpose tools in adverse tool-use conditions; and
can be used for insertion of a wide selection of internal retainer rings.
This invention accomplishes these and other objectives with a piston-pin lock-ring-insertion tool having a ring-insertion tube in ring-insertion relationship to a ring pusher. The ring-insertion tube has an inside periphery with a press-close taper that is tapered inwardly from a ring-feeder end to a ring-guide bore that is cylindrical uniformly intermediate the press-close taper and a ring-insertion end of the ring-insertion tube. The ring-insertion end of the ring-insertion tube has a perpendicularity surface that is adapted for alignment of the ring-guide bore and a piston-pin bore in a crankshaft-engine piston. The ring pusher has a pusher taper with a pusher head adapted for being buttressed against a side of lock ring for pushing the lock ring from a major diameter to a minor diameter of the press-close taper proximate a circumferential entrance to the ring-guide bore. The ring pusher has a slide rod that is oppositely disposed end-to-end from the pusher head. The slide rod has a cylindrical outside periphery that slides against an inside periphery of the ring-guide bore. The slide rod has an insertion plunger on a cylindrical step inwardly to a center rod that is extended concentrically from the insertion plunger.
A use method includes pushing a lock ring sidewardly with the pusher head to the ring-guide bore, reversing the ring pusher end-to-end, inserting the center rod into the lock ring, aligning the center rod with the piston-pin bore, and pushing the lock ring into an internal groove in the piston-pin bore.
The above and other objects, features and advantages of the present invention should become even more readily apparent to those skilled in the art upon a reading of the following detailed description in conjunction with the drawings wherein there is shown and described illustrative embodiments of the invention.
REFERENCES:
patent: 1740590 (1929-12-01), Hartman
patent: 2357139 (1944-08-01), Seme
patent: 2488001 (1949-11-01), Birk
patent: 2839823 (1958-06-01), Brancato
patent: 3030677 (1962-04-01), Kindt et al.
patent: 3030700 (1962-04-01), Jensen
patent: 3134168 (1964-05-01), Erdmann
patent: 3631688 (1972-01-01), Quick
patent: 3995360 (1976-12-01), Millheiser
patent: 4514889 (1985-05-01), Ferlan et al.
patent: 5146676 (1992-09-01), Cuba
patent: 5794984 (1998-08-01), Bartholomew
patent: 6113306 (2000-09-01), Allert
patent: 6389667 (2002-05-01), Cook et al.
patent: 6507985 (2003-01-01), Loughlin et al.
patent: 3041260 (1982-05-01), None
patent: 3824617 (1989-10-01), None
patent: 2649349 (1991-01-01), None
patent: 62-039133 (1987-02-01), None
patent: 02-024028 (1990-01-01), None
Bryant David P.
Compton Eric
Edward M. Livingston, P.A.
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