Injection device

An injection device, comprising:

• a housing,
• a retainer axially movable within said housing for movement therein, during an injection, between a distal position and a proximal position thereof,
• a fluid container within said retainer,
• a plunger axially movable within said fluid container,
• a driving member axially displaceable within said housing,
• a toothed rod disposed in said housing for axial displacement therein and for acting on said plunger to express fluid from said fluid container during an injection,
• a first coupling device provided on said retainer and cooperating with teeth of said toothed rod, which normally locks said toothed rod to said retainer but permits relative axial movement therebetween while said retainer is not within a first predetermined axial position range inside said housing, and said toothed rod is moving in a predetermined axial rod movement direction, and
• a second coupling device provided on said driving member, and cooperating with teeth of said toothed rod, which normally locks said driving member to said toothed rod but permits relative axial movement therebetween while said driving member is not within a second determined axial position range inside said housing, and said driving member is moving in a predetermined driving member axial movement direction, and further comprising,
• coupled to the driving member, a detent mechanism, and a spring, acting upon the driving member in the proximal direction, and adapted to be compressed by moving the driving member and detent mechanism in the distal direction, said detent mechanism engaging against a fixed portion of said housing when a predetermined cocked position is reached.

An injection device, comprising

• a housing,
• a retainer axially movable within said housing for movement therein, during an injection, between a distal position and a proximal position thereof,
• a fluid container within said retainer,
• a plunger axially movable within said fluid container,
• a driving member axially displaceable within said housing,
• a toothed rod disposed in said housing for axial displacement therein and for acting on said plunger to express fluid from said fluid container during an injection,
• a first coupling device provided on said retainer, and cooperating with teeth on said toothed rod, which normally locks said toothed rod to said retainer but permits relative axial movement therebetween while said retainer is not within a first predetermined axial position range inside said housing, and said toothed rod is moving in a predetermined axial rod movement direction, and
• a second coupling device provided on said driving member, and cooperating with teeth on said toothed rod, which normally locks said driving member to said toothed rod but permits relative axial movement therebetween while said driving member is not within a second predetermined axial position range inside said housing, and said driving member is moving in a predetermined driving member axial movement direction, and wherein
• the housing comprises two parts, and a device is provided for changing the relative position of the housing parts by linearly moving them relative to each other.

An injection device having

• a housing for receiving a container for a fluid to be injected,
• an actuating member,
• a toothed rod, having a longitudinal axis that is axially movable in response to said actuating member to expel fluid from a container disposed in the housing, and
• an axially movable part which engages against said toothed rod,
• wherein, in accordance with the, invention,
• the toothed rod, viewed in cross section transverse to its longitudinal axis, is polygonal;
• at least two sides of a plurality of sides of said rod are each formed with a respective row of teeth, and said rows of teeth cooperate with said axially movable part;
• said rows of teeth each have a predetermined tooth division,
• said axially movable part comprises a plurality of engaging members, and each engaging member is formed with at least one engaging element having a shape substantially complementary to a cooperating one of said rows of teeth and each engaging member is elastically biassed against said cooperating row of teeth,
• and wherein, in order to facilitate finer adjustment of an axial position of said toothed rod within said housing, there is an axial offset among at least one of
• the respective rows of teeth with respect to each other, and
• the engaging elements on the respective enagaging members with respect to each other.