Abstract: An electric hydraulic floor jack includes a variable plunger structure provided on a motor base and an oil pump base. The variable plunger structure includes a piston hole formed in the oil pump base and communicating with an oil chamber and an oil inlet passage, a plunger sleeve provided at a port of the piston hole, a plunger slidably provided in the plunger sleeve, a U-shaped piston slidably provided in the piston hole, a valve trim slidably provided on the piston, a spring provided in the piston hole and sleeved on the valve trim, and an eccentric wheel provided on an output shaft of a speed reducer. The plunger is driven by the eccentric wheel in cooperation with the spring to continuously make a linear reciprocating motion, thereby continuously opening and closing the check valve, and pumping oil into the cylinder to push the piston rod for lifting work.

Abstract: A jack with a double high-pressure structure is provided, including a base, a pump body installed on the base, an oil cylinder, an oil drain valve, and a safety valve. The base is provided with a low-pressure check valve and a high-pressure check valve A. It is characterized in that a high-pressure check valve B is also installed on the base. The present invention can improve the safety performance during use and prolong the service life.

Abstract: A jack with a protecting structure of a pump piston and a method for using the same are provided. The jack includes a housing, a base located inside the housing, and the protecting structure. An oil cylinder and a pump body are installed on the base. A pump piston is installed on the pump body. A spring is installed on the pump piston and the pump body. A stop protrusion is arranged on the pump piston. The protecting structure includes a dustproof sleeve and a wool felt. The dustproof sleeve is installed on the base and the pump piston. One end of the dustproof sleeve is detachably fixed on the base through a fastener. The other end of the dustproof sleeve is connected to an end portion of the pump piston. The shape of the dustproof sleeve is set into a wavy type.

Abstract: A jack with a double high-pressure structure is provided, including a base, a pump body installed on the base, an oil cylinder, an oil drain valve, and a safety valve. The base is provided with a low-pressure check valve and a high-pressure check valve A. It is characterized in that a high-pressure check valve B is also installed on the base. The present invention can improve the safety performance during use and prolong the service life.

Abstract: A jack with a protecting structure of a pump piston and a method for using the same are provided. The jack includes a housing, a base located inside the housing, and the protecting structure. An oil cylinder and a pump body are installed on the base. A pump piston is installed on the pump body. A spring is installed on the pump piston and the pump body. A stop protrusion is arranged on the pump piston. The protecting structure includes a dustproof sleeve and a wool felt. The dustproof sleeve is installed on the base and the pump piston. One end of the dustproof sleeve is detachably fixed on the base through a fastener. The other end of the dustproof sleeve is connected to an end portion of the pump piston. The shape of the dustproof sleeve is set into a wavy type.