A diaphragm accumulator provided with a flexible diaphragm inside an accumulator housing has a stress relaxing member having a contact surface which the diaphragm deformed by a pressure fluctuation inside the accumulator housing contacts and regulating the deformed attitude of the diaphragm by the contact surface on the inner surface. When the diaphragm is deformed by the pressure fluctuation inside the accumulator housing, the stress relaxing member regulates the deformed attitude of the diaphragm to reduce a stress generated in the diaphragm.

An accumulator is provided with a communication passage which allows communication between a space inside a gas filling opening and a gas filled chamber in a state where a diaphragm contacts an opening peripheral edge of the gas filling opening and which is formed by, for example, uneven shapes provided in either or both of the diaphragm or/and the opening peripheral edge of the gas filling opening.

A diaphragm accumulator provided with a flexible diaphragm inside an accumulator housing has a stress relaxing member having a contact surface which the diaphragm deformed by a pressure fluctuation inside the accumulator housing contacts and regulating the deformed attitude of the diaphragm by the contact surface on the inner surface. When the diaphragm is deformed by the pressure fluctuation inside the accumulator housing, the stress relaxing member regulates the deformed attitude of the diaphragm to reduce a stress generated in the diaphragm.

A hydraulic circuit includes a control valve, a first hydraulic actuator, and a second hydraulic. The hydraulic circuit is configured such that in a first step, the first hydraulic actuator opens a product barrier in response to movement of the control valve into a first position, in a second step, the second hydraulic actuator moves a product engagement member in a first direction and the first hydraulic actuator closes the product barrier in response to movement of the control valve into a second position, in a third step, the first hydraulic actuator opens the product barrier in response to movement of the control valve into the first position, and in a fourth step, the second hydraulic actuator moves the product engagement member in a second direction and the first hydraulic actuator closes the product barrier in response to movement of the control valve into the second position.