Pumping device

A pumping device for pumping a product from a container, the pumping device comprising an actuator and a closure, the actuator being connected to the closure,

• the pumping device further comprises a collapsible bladder, the collapsible bladder being formed by connecting a plurality of segments, an included angle being formed between two adjacent segments, the collapsible bladder being configured such that the collapsible bladder is collapsed when a pressing force is applied directly or indirectly to the collapsible bladder, and the collapsible bladder is stretched when the pressing force is removed, at least two adjacent segments are connected to each other by means of a weakened portion, such that the resilience force of the collapsible bladder that is generated during pressing is less than a force required for restoring the collapsible bladder, or the collapsible bladder itself does not have the capability to generate a resilience force;
• wherein the weakened portion is in the form of at least one of the following structures:
• an outer notch portion opened toward an outer side of the included angle, an inner notch portion opened toward an inner side of the included angle, and a thin-walled portion;
• and
• wherein an elastic restoring mechanism is arranged in the internal space of the collapsible bladder, with an upper end of the elastic restoring mechanism being supported on the actuator or the top of the collapsible bladder, and a lower end of the elastic restoring mechanism being supported on one of the closure, the actuator and the lower portion of the collapsible bladder.