Clamping mechanism for a beverage preparation machine

A clamping mechanism for a beverage preparation machine comprises a support 33, a holder 37 for a beverage cartridge, and a clamp 30. The holder is capable of being coupled to and decoupled from the support. Wherein the holder is rotatable about a first axis of the clamping mechanism between: a first position, in which the holder is able to be coupled to or decoupled from the support and the holder and clamp are relatively spaced apart in the direction of the first axis; and a second position in which the holder is retained to the support and the holder and clamp are relatively close to one another in the direction of the first axis such that a beverage cartridge held in use in the holder is clamped between the holder and the clamp. The clamping mechanism further comprises an inlet piercer (86), near the periphery of lower part 52, for forming an inlet in the beverage cartridge. Wherein the inlet piercer forms part of, or is coupled to, the clamp and is able to rotate with the holder about the first axis.