Patent ID: 7674240

Claim:
An apparatus comprising: a releasable latch positioning a proximal housing relative to a distal housing, the distal housing coupled to a syringe tube and the proximal housing coupled to a plunger, the plunger disposed within the syringe tube; a screw mechanism coupling at least one of the syringe tube to the distal housing and the plunger to the proximal housing, to move the plunger along a length of the syringe tube; wherein the latch defines a first latched position to removably lock the latch to locate the plunger at a first location along the length and a second latched position to removably lock the latch to locate the plunger at a different second location along the length proximal to the first location, the releasable latch further comprising: a cowling attached to the distal housing, the cowling comprising: an inner surface extending over an exterior surface of the proximal housing; at least one cowling recess in the inner surface; the exterior surface comprising at least two indexing locks to engage the at least one cowling recess; wherein the at least one cowling recess comprises at least one cowling groove radially around an inner diameter of the cowling, wherein the latch is locked at the first latched position when the at least two indexing locks are removably engaged in the at least one cowling groove, and the latch is locked at the second latched position when the at least two indexing locks are one of beyond and removably engaged with an end of the cowling.