Bone cement injector gun

A paste injector gun comprising:

• a housing having a longitudinal axis;
• a drive plate mounted in the housing for translation along the longitudinal axis;
• a shaft mounted in the housing for translation along the longitudinal axis, the shaft passing through the drive plate;
• a trigger pivotably attached to the drive plate at a pivot point and extending from the drive plate;
• and
• a first fulcrum mounted on the housing opposite the trigger such that when the trigger pivots about the pivot point the trigger contacts and rotates about the fulcrum and the drive plate is moved along the axis carrying the shaft with it, the housing further including a U-shaped opening for receiving a cartridge and the paste injector gun further includes a gate hinged at one end to the housing, the gate rotatable between an open position in which a cartridge can be positioned in the U-shaped opening and a closed position in which the gate closes the U-shaped opening for positive retention of the cartridge, the gate further including a closure tab extending from an end opposite the hinged end and the housing includes a tab receiving slot, the closure tab fitting into the tab receiving slot when the gate is in the closed position and a spring loaded detent is mounted adjacent the tab receiving slot and projects into the tab receiving slot, the closure tab including a depression for receiving the detent when the gate is in the closed position.

A paste injector gun comprising:

• a trigger;
• first pivot means for providing a first center of rotation for the trigger, the first pivot means corresponding to a first mechanical advantage;
• and
• second pivot means for providing a second center of rotation for the trigger, the second pivot means corresponding to a second mechanical advantage, the second pivot means being rotatable between a first position in which it is not engageable with the trigger and a second position in which it is engageable with the trigger.