Flash activated passive shielding needle assembly

A needle assembly comprising:

• a housing including a passageway extending therethrough and a needle cannula having a puncture tip extending from a forward end thereof;
• a shielding member movable with respect to the housing between a first position in which the puncture tip of the needle cannula is exposed and a second position in which the puncture tip of the needle cannula is shielded by the shielding member, the shielding member maintained in the first position against a biasing force provided by a drive member biasing the shielding member toward the second position;
• an activation material associated with the shielding member and adapted to deform upon a flow of a fluid through the passageway of the housing;
• and
• capillary tubes disposed within the passageway of the housing and in fluid communication with the needle cannula for diverting the fluid from the needle cannula to the activation material,
• wherein the fluid flowing through the passageway of the housing causes the activation material to deform, thereby releasing the shielding member from the first position and causing the drive member to bias the shielding member toward the second position.

A shielding needle assembly comprising:

• a needle cannula having a proximal end and a distal end with a puncture tip;
• a needle hub having a proximal end and a distal end and a passage between the proximal and distal ends of the needle hub, with an interior portion of the needle hub distal end supporting the needle cannula proximal end;
• a shielding member movable between a first position in which the puncture tip of the needle cannula is exposed and a second position in which the puncture tip of the needle cannula is shielded by the shielding member;
• a drive member biasing the shielding member toward the second position, the shielding member and the needle hub including an interference engagement therebetween for maintaining the shielding member in the first position against a biasing force of the drive member;
• and
• an activation material located within the passage, the activation material adapted to expand, contract, or otherwise change in dimension upon direct contact with a fluid medium flowing through the needle cannula, wherein the fluid medium flows into and through the needle cannula and the fluid medium is then diverted to the passage where the fluid medium contacts the activation material thereby causing the activation material to expand, contract, or otherwise change in dimension and release the interference engagement between the shielding member and the needle hub and allowing the drive member to bias the shielding member toward the second position, the shielding needle assembly further comprising capillary tubes disposed within the passage of the needle hub and in fluid communication with the needle cannula for diverting the fluid medium from the needle cannula to the activation material.

A method of actuating a shielding needle assembly comprising:

• providing the shielding needle assembly comprising a housing including a passageway extending therethrough;
• a needle cannula having a proximal end located within the passageway and a puncture tip extending from a forward end thereof and a shielding member in a first position biased toward a second position in which the puncture tip of the needle cannula is shielded by the shielding member, the shielding member maintained against the bias in the first position in which the puncture tip of the needle cannula is exposed;
• and an activation material located within the passageway and associated with the shielding member, the activation material adapted to expand, contract, or otherwise change in dimension upon direct contact with a fluid medium flowing through the needle cannula, wherein the fluid medium flows into and through the needle cannula and the fluid medium is then diverted to the passageway where the fluid medium contacts the activation material;
• and
• inserting the puncture tip of the needle cannula through skin of a patient to allow the fluid medium to flow through the needle cannula;
• wherein the fluid medium flows through the needle cannula causing the activation material to expand, contract, or otherwise change in dimension upon direct contact with the fluid medium, thereby releasing the shielding member from the first position, the method further comprising providing capillary tubes within the passageway of the housing and in fluid communication with the needle cannula for diverting the fluid medium from the needle cannula to the activation material.