Patent ID: 8061887

Claim:
A cartridge in which bone cement is mixed and from which bone cement is discharged, said cartridge including: a cylinder having opposed first and second ends, an inner surface that defines a mixing chamber that extends between the ends, a first end face that extends over the first end and an opening through the first end face into the mixing chamber; a component releasably mounted to the cylinder first end that, when mounted to said cylinder, closes the first end face opening; a piston slidably disposed in the cylinder mixing chamber that can move from a position adjacent the second end towards the first end, said piston having a face that is directed towards the cylinder first end; a locking member associated with said piston that selectively prevents movement of said piston through the cylinder mixing chamber toward the first end face; a shaft that extends from outside of the cylinder through one of the cylinder ends into the cylinder mixing chamber, said shaft mounted to said cylinder so as to be able to rotate within the mixing chamber and move longitudinally within the mixing chamber; and a blade disposed in said mixing chamber, said blade shaped to have: a hub connected to said shaft; first, second and third vanes, each said vane having an edge, said vanes being connected together such that said second vane is located between said first and third vanes, said second vane shaped so as to have an edge that subtends at least a portion of the cylinder inner surface that is located adjacent the cylinder inner surface and the first and third vanes are shaped so that the first and third vane edges are angled relative to the second vane edge; and at least one web that extends between said hub and said vanes, wherein: said web connects said vanes to said hub so that at least one of the first or third vanes is longitudinally displaced from said hub so that, when said blade is proximal to the cylinder first end, the first vane edge is disposed against the cylinder first end face and, when said blade is proximal to said piston, the third vane edge is disposed against the piston face; and said web flexibly connects said vanes to said hub so that, when said blade is compressed between the cylinder first end and said piston, at least one of the first or third vanes moves toward said hub.