Medical injector with ratcheting plunger

摘要

A medical injector has a body with a displaceable plunger. The plunger includes a plurality of spaced-apart ratchet teeth disposed along the length thereof. At least one indexer is provided to engage the plunger, wherein the indexer is configured to allow the plunger to displace distally toward a distal end of the body but not proximally toward a proximal end of the body. The medical injector also includes an actuator having an engagement portion formed to engage one or more of the ratchet teeth. The actuator is displaceable to a ready state, the engagement portion being displaced proximally relative to the plunger with the actuator being displaced to the ready state. The indexer prevents proximal movement of the plunger, thereby allowing the engagement portion to bypass one or more of the ratchet teeth with the actuator being displaced to the ready state. In addition, the actuator is displaceable from the ready state to cause actuation of the medical injector. The displacement from the ready state causes distal displacement of the engagement portion with the engagement portion engaging one or more of the ratchet teeth and causing distal displacement of the plunger with the engagement portion.

主权项

1. A medical injector, comprising:
a body having a distal end and a proximal end; a displaceable plunger disposed in the body, the plunger having a plurality of spaced-apart ratchet teeth disposed along the length thereof; at least one indexer formed to engage the plunger, wherein the indexer is configured to allow the plunger to displace distally toward the distal end of the body but not proximally toward the proximal end of the body; and an actuator having an engagement portion formed to engage one or more of the ratchet teeth, wherein the actuator of the plunger comprises:
a first actuator portion on which the engagement portion is disposed; anda second actuator portion, the second actuator portion being rotatably coupled to the firstactuator portion, the second actuator portion being rotatably displaceable to a ready state,the engagement portion being displaced proximally relative to the plunger upon thesecond actuator portion being displaced to the ready state, the indexer preventingproximal movement of the plunger, thereby allowing the engagement portion to bypassone or more of the ratchet teeth while contacting the plunger, upon the second actuatorportion being displaced to the ready state; wherein the second actuator portion is displaceable from the ready state to cause actuation of the medical injector, the displacement from the ready state causing non-rotating displacement of the first actuator portion and a distal displacement of the engagement portion, with the engagement portion engaging one or more of the ratchet teeth and causing distal displacement of the plunger; and wherein the actuator further comprises a rocker pivotably connected to the first actuator portion and pivotably connected to the body.