Patent ID: 9579471
Date: 2017-02-28
CPC Classifications: A61M

Claim:
1. Injection assistance device for an injection device for injecting a product into an injection site, the injection assistance device comprising at least one hollow body intended to receive a product that is to be injected, at least one hollow injection needle intended to penetrate the injection site, and at least one piston plunger housed in said body, said body and said piston plunger being able to be moved in axial translation one with respect to the other, said injection assistance device comprising: a restraining ring element coupled to the body, an outer sleeve which receives at least a portion of said body, said outer sleeve having a grasping surface and a deflectable leg, said body movable within said outer sleeve between a first position, in which said needle is shielded by said injection assistance device, and a second position, in which said needle is exposed from said injection assistance device by a predetermined insertion length L, the leg providing interference engagement with the restraining ring element and retaining the body in the first position, a first inner sleeve having a proximal projection, the first inner sleeve movable relative to the outer sleeve between a first inner sleeve position in which the proximal projection is spaced from the leg, and a second inner sleeve position in which the proximal projection contacts the leg, and a spring between the outer sleeve and the restraining ring element, the spring coupled to said body and to said outer sleeve, said spring in a partially expanded state so as to dampen limited movement of said outer sleeve, in at least one of two directions, respectively distal or proximal, during an injection, and to maintain said body in said second position and said needle at said predetermined insertion length L, during the injection, wherein proximal movement of the first inner sleeve relative to the outer sleeve to the second inner sleeve position causes the proximal projection to contact and deflect the leg outwardly to release the interference engagement between the leg and the restraining ring element, permitting the spring to automatically move the body from the first position to the second position.