Patent ID: 6676390
Filing Date: 2004-01-13
Classification: F04B

Abstract:
A manual air pump with a handle comprising a base member, a foot switch mounted on the base member, an outer cylinder mounted vertically on the base member, an inner cylinder mounted vertically on the base member inside the outer cylinder, a pumping assembly moveably mounted in the outer cylinder and securely attached to the inner cylinder, whereinthe base member with a wing plate extends laterally from the base and is adapted to be stepped on by a user to hold the manual air pump in place during operation of the pump, and includes: an outlet defined in the base member to provide compressed air to a discharge tube that is adapted to be connected to an object to be inflated; a first longitudinal path centrally defined in the base member; a second longitudinal path defined in the base member; a first lateral path defined in the base member and communicating between the outlet and the first longitudinal path; a second lateral path defined in the base member and communicating between the outlet and the second longitudinal path; a first ball check valve mounted in the first longitudinal path to prevent compressed air from flowing back from the outlet; and a first check valve mounted in the second lateral path to prevent compressed air from flowing back from the outlet into the second longitudinal path; the foot switch is partially received in the second longitudinal path to selectively separate the second lateral path and the second longitudinal path; the outer cylinder communicates with the second longitudinal path in the base member; the pumping assembly includes: a central cylinder mounted around the inner cylinder, the central cylinder having a diameter smaller than that of the outer cylinder and greater than that of the inner cylinder, the central cylinder having a first end extending out of the outer cylinder and a second end mounted in the outer cylinder; a handle mounted on the first end of the central cylinder (51) for the user to drive the pumping assembly; a piston mounted on the second end of the central cylinder, the piston being movable relative to an inner periphery of the outer cylinder and an outer periphery of the inner cylinder; a second check valve mounted around the piston and selectively abutting the inner periphery of the outer cylinder to only allow compressed air to flow downward between the outer cylinder and the central cylinder; and a third check valve mounted in the piston and selectively abutting the outer periphery of the inner cylinder to only allow compressed air to flow upward between the outer cylinder and the inner cylinder; the inner cylinder includes a valve block mounted on a top of the inner cylinder and a fourth check valve mounted around the valve block and selectively abutting an inner periphery of the central cylinder to only allow compressed air to flow upward between the central cylinder and the inner cylinder; and a discharge tube has a first end communicating with the outlet in the base member and a second end adapted to be connected to a object to be inflated.