Pressure booster and cylinder apparatus provided with same

A pressure booster comprising:

• a cylinder main body having two cylinder chambers divided by a division wall;
• a first piston slidably disposed in one cylinder chamber of the two cylinder chambers and dividing an inside of the one cylinder chamber into a pressure boosting chamber and a first chamber;
• a second piston slidably disposed in another cylinder chamber of the two cylinder chambers and dividing an inside of the other cylinder chamber into a second chamber and a third chamber;
• a rod provided so as to pass through the division wall and configured to couple the first piston and the second piston to each other;
• and
• a biasing member configured to bias at least one of the first piston and the second piston in a direction in which the first piston moves toward the pressure boosting chamber, wherein
• the cylinder main body is provided with
• a first introduction port configured to introduce fluid into the pressure boosting chamber,
• a first atmospheric port configured to make an inside of the first chamber open to an atmosphere,
• a second introduction port configured to introduce the fluid into the second chamber,
• a second atmospheric port configured to make an inside of the third chamber open to the atmosphere, and
• a lead-out port configured to lead the fluid pressurized in the pressure boosting chamber out of the pressure boosting chamber,
• the second piston is provided with a communicating member having a communicating hole configured to make the second chamber and the third chamber communicate with each other, the communicating member being configured to be displaced to a communicating position in which the second chamber and the third chamber communicate with each other via the communicating hole and an interruption position in which a communicating state between the second chamber and the third chamber is interrupted, and
• the communicating member is configured to be displaced from the communicating position to the interruption position as a result of the communicating member making contact with the cylinder main body when the first piston and the second piston are displaced in a direction in which the pressure boosting chamber contracts, and the communicating member is configured to be displaced from the interruption position to the communicating position as a result of the communicating member making contact with the cylinder main body when the first piston and the second piston are displaced in a direction in which the pressure boosting chamber expands.