Patent ID: 8123084

Claim:
A device for mixing a substance comprised of two constituents, the device comprising: a cartridge ( 12 ); a cartridge holder ( 32 ); said cartridge having a fluid communication end ( 14 ) and an actuation end ( 16 ), said fluid communication end ( 14 ) being receivable in said cartridge holder ( 32 ), said cartridge having a first closure member ( 18 ) disposed at the fluid communication end, a second closure member ( 20 ) disposed at the actuation end ( 16 ), a piston ( 22 ) within the cartridge intermediate the first and second closure members, and a by-pass channel ( 24 ) for enabling fluid to by-pass the piston ( 22 ) when the piston is in a by-pass position; a plunger rod ( 46 ) engageable with the second closure member ( 20 ) for moving the second closure member ( 20 ) within the cartridge, said plunger rod having a rack gear ( 48 ) formed thereon, said rack gear ( 48 ) having a length to permit said plunger rod ( 46 ) to advance said second closure member ( 20 ) only to proximate said by-pass channel ( 24 ); a housing ( 42 ) , a pinon gear ( 50 ) mounted within said housing, said pinon gear ( 50 ) being engageable with said rack gear ( 48 ), and a handle ( 54 ) connected to said pinion gear.