Pump assembly

A pump assembly for a dental cleaning appliance, the pump assembly comprising:

• a positive displacement pump comprising a fluid chamber having a fluid inlet connectable to a source of fluid and a fluid outlet, and a fluid displacement member which is moveable in a linear direction relative to the fluid chamber;
• a drive for actuating the pump to draw fluid into the fluid chamber through the fluid inlet;
• an energy storage device for converting kinetic energy generated during actuation of the pump by the drive into potential energy, and storing the potential energy;
• a cam connected to the drive for rotation relative to the fluid displacement member, the cam comprising a ramp extending about the fluid displacement member, the ramp having an end which is spaced from a start of the ramp along said linear direction;
• and
• a cam follower connected to the fluid displacement member so as to engage the ramp;
• whereby, as the cam moves relative to the fluid displacement member, the cam follower (i) moves along the ramp to actuate the pump to draw fluid into the fluid chamber, and (ii) moves beyond the end of the ramp to enable the energy storage device to use stored potential energy to actuate the pump to urge a burst of fluid from the fluid chamber.