Locking syringe with integrated bias member

An apparatus comprising:

• a housing including a hollow interior cavity, a distal end, and a proximal end, the distal end configured to interface with a medical device and including an opening into the hollow interior cavity, the proximal end including a peripheral flange;
• a plunger including a shaft and a piston at a distal end of the shaft, the piston including a peripheral sealing surface configured to slidably engage an inside surface of the hollow interior cavity of the housing to form a movable seal, the shaft extending beyond the proximal end of the housing;
• a bias member with a distal end coupled to the plunger and a proximal end restrained proximate to the proximal end of the housing, the bias member configured to assist the plunger in pressurizing the hollow interior cavity of the housing;
• a cap assembly including,
• a base cap engaging the shaft and located at the proximal end of the housing, the base cap configured to secure the piston within the housing,
• a locking ring to engage the peripheral flange,
• a double ring handle portion with a distal end engaging the locking ring, and
• a tension spring disposed between the double ring handle and a portion of the base cap;
• a user-actuatable locking member embedded within the double ring handle and spring loaded to user-selectively inhibit unwanted movement of the plunger when engaged, the locking member including a beveled outer edge;
• and
• wherein the double ring handle includes a beveled peripheral portion on an inside edge of the proximal end of the double ring handle configured to slidably engage the locking member when pressure is applied to the double ring handle toward the proximal end of the housing.