Manual bone cement mixing device
OwnerWilliam M. Murrayinventor
Life of this patent
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Abstract
A device for mixing bone cement is disclosed. Dry PMMA powder and MMA liquid are mixed in a vacuum chamber by a rotary mixer having a pair of spaced mixing arms. The rotary mixer is manually rotated by a gear drive. The arms of the rotary mixer follow continuous paths, each path having a plurality of loops at the wall of the chamber and curved portions extending across the chamber between loops. The arms move through the cement, break bubbles and thoroughly mix the PMMA and MMA. Gas from broken bubbles is vacuum drawn from the mixer to a vacuum source.
Claims27
A device for mixing bone cement and removing gas from the cement comprising:
- a) a hollow housing having a wall, an open top and a vacuum tube attachment fitting defining a passage extending through the housing wall;
- b) a bone cement mixing chamber in the housing;
- c) a cap adapted to be fitted on the top of the housing over the mixing chamber to close the housing;
- d) a rotary mixer having a central shaft and a first mixing arm located a distance to one side of the central shaft, said mixing arm extending along the length of the mixing chamber to the bottom of the chamber;
- and
- e) a mixer drive on the cap, the drive including,
- i) an input drive shaft rotatably mounted on the cap and having an end extending above the cap;
- ii) a rotary drive member attached to the input drive shaft extending above the cap for rotating the input drive shaft;
- iii) an output drive member mounted on the interior of the cap a distance away from the input drive shaft, the output drive member being connected to the rotary mixer central shaft so that rotation of the drive member rotates the central shaft to move the mixer arm in the mixing chamber;
- and
- iv) drive means joining the input drive shaft and the output drive member for simultaneously moving the output drive member along a closed path extending around the input drive shaft, rotating the output drive member about an axis located away from the input drive shaft, and moving the mixing arm along a first path in the chamber having a number of loops located adjacent to and spaced around the interior sidewall of the chamber and portions extending across the interior of the chamber between successive adjacent loops on the first path.
A device for mixing a volume of bone cement and removing gas from the cement, the device comprising:
- a) a hollow housing having a wall, an open top and a vacuum tube attachment fitting defining a passage through the wall;
- b) a hollow bone cement mixing chamber having an interior sidewall, an open top and a bottom, said mixing chamber located in the housing;
- c) a cap adapted to be fitted on the top of housing to close the housing top and overlie the chamber;
- d) a bone cement mixer in the mixing chamber having a first mixer arm extending from the top of the chamber to a first end located at the bottom of the chamber;
- and
- e) a mixer drive supported on the cap, said drive including,
- i) an input drive member movably mounted on the cap;
- ii) an output drive member movably mounted on the inside of the cap and located away from the input drive member;
- said output drive member being connected to said bone cement mixer so that the output drive member and mixer move together;
- iii) a manual drive member outside the cap operatively connected to the input drive member for rotating the input drive member;
- and
- iv) a second mixer drive member joining the input and output drive members for simultaneously moving the output drive member along a first path within the mixing chamber, rotating the mixer about an axis away from the input drive member and moving the mixer arm along a second path having a plurality of spaced loops located near the chamber sidewall and curved portions which extend through the chamber between successive loops along said second path, when the input drive member is moved by the first mixer drive means.
Dependencies are inferred from the claim text.