Pumps – Expansible chamber type – Moving cylinder
Reexamination Certificate
2001-01-22
2001-12-04
Thorpe, Timothy S. (Department: 3746)
Pumps
Expansible chamber type
Moving cylinder
C417S559000, C417S569000, C092S015000, C092S052000
Reexamination Certificate
active
06325601
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a manual air pump for inflating, e.g., bicycle tires, and more particularly to a dual-mode manual air pump that may in one mode provide a very high volume of air per stroke and in another mode provide less volume of air at high pressure.
2. Description of the Related Art
Bicycle pumps include two typical types: 1) big bore for high volume per stroke and low pressure for rapid inflation, yet high pressure operation is difficult to achieve; and 2) small bore for low volume per stroke and high pressure for inflating bicycle tires to high pressure. U.S. Pat. No. 5,443,370 issued to Wang on Aug. 22, 1995 proposes a two-cylinder manual air pump having selectable high volume and high pressure modes, wherein the pump in one mode provides a very high volume of air per pump stroke and in another mode provides less volume per stroke but enables the user to inflate to higher pressures. Nevertheless, manufacture, assembly, and use of such manual air pumps are complicated and troublesome. The structure in the cylinders for air passage is too complicated. In addition, the thinner piston rod might be broken during the output stroke, as the travel for the thinner piston rod is relatively long and as the piston on the thinner piston rod encounters much higher pressure when the piston approaches the inner end of the outer cylinder. Namely, the thinner piston rod tends to be broken and requires a larger force to push it. Further, the manual air pump is too long when in a fully extended status. Further, the manual air pump generates noise during inflation.
Applicant's U.S. Pat. No. 6,257,849 discloses a manual air pump to solve the above problems. The present invention is intended to provide an improved design in this regard.
Summary of the Invention
A manual air pump in accordance with the present invention comprises:
an outer cylinder comprising a chamber therein and including a first end and a second end;
a head provided to the second end of the outer cylinder, the head including an outlet passage communicated with the chamber for supplying air to an object to be inflated;
an inner cylinder reciprocatingly mounted in the outer cylinder and including a longitudinal bore, the inner cylinder including a first end distal to the head and a second end adjacent to the head, an outer piston being attached to the second end of the inner cylinder to move therewith, the outer piston including a passage for communicating the longitudinal bore of the inner cylinder with one of the outlet passage of the head and the chamber of the outer cylinder;
a piston rod reciprocatingly mounted in longitudinal bore of the inner cylinder and having a first end and a second end, an inner piston being attached to the second end of the piston rod to move therewith; and
a handle secured to the first end of the piston rod to move therewith,
wherein the inner cylinder is rotatable relative to the outer cylinder, and when the inner cylinder is in a first angular position relative to the outer cylinder for high-volume inflation, the inner cylinder is reciprocatingly and longitudinally movable relative to the outer cylinder; and
wherein when the inner cylinder is in a second angular position relative to the outer cylinder for high-pressure inflation, the inner cylinder is immobile in a longitudinal direction relative to the outer cylinder.
The first end of the outer cylinder has a tubular stop member fixed thereon. The inner cylinder extends through the tubular stop member and includes a first stop on an outer periphery thereof and adjacent to the first end thereof. The tubular stop member includes a second stop that defines a receiving space therein. When the inner cylinder is in the first angular position relative to the outer cylinder for high-volume inflation, the first stop of the inner cylinder is not received in the receiving space such that longitudinal outward and inward movement of the inner cylinder relative to the outer cylinder is allowed. When the inner cylinder is in the second angular position relative to the outer cylinder for high-pressure inflation, the first stop of the inner cylinder is received in the receiving space such that the longitudinal outward movement of the inner cylinder relative to the outer cylinder is prevented by the second stop.
The outer periphery of the inner cylinder further includes a longitudinal guide strip formed thereon. A gap is defined between the longitudinal guide strip and the first stop of the inner cylinder. The stop member includes a longitudinal recessed portion in an inner periphery thereof. Rotational movement of the inner cylinder relative to the outer cylinder is allowed only when the stop member is located in the gap. The stop member is located in the gap when the inner cylinder is moved to a predetermined longitudinal position relative to the outer cylinder. In an embodiment of the invention, the stop member is located in the gap when the outer piston on the inner cylinder is in its innermost position relative to the outer cylinder.
The longitudinal guide strip of the inner cylinder is guided by the longitudinal recessed portion of the stop member during longitudinal movement of the inner cylinder relative to the outer cylinder, thereby preventing relative rotation of the inner cylinder relative to the outer cylinder during high-volume inflation.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 624917 (1899-05-01), Feeny
patent: 670811 (1901-03-01), Phelps
patent: 799786 (1905-09-01), Freel
patent: 1474204 (1923-11-01), MacGregor
patent: 1522370 (1925-01-01), Jenney
patent: 2450295 (1948-09-01), Parker et al.
patent: 3452647 (1969-07-01), Herrell
patent: 4508490 (1985-04-01), Ramirez et al.
patent: 5443370 (1995-08-01), Wang
patent: 5655890 (1997-08-01), Liao
patent: 5779457 (1998-07-01), Chuang et al.
patent: 5873705 (1999-02-01), Chen
patent: 6257849 (2000-11-01), Wu
Kamrath Alan
Rider Bennett Egan & Arundel LLP
Solak Timothy P.
Thorpe Timothy S.
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