Piston drive arrangement for injector
First Claim
Patent Images
1. In an apparatus for dispensing liquid including a liquid chamber with an outlet slidably mounting a piston therein for sliding movement axially along an expelling axis toward the outlet to force liquid from the outlet and a drive member movable axially along the expelling axis to engage and force the piston toward the outlet;
- the improvement comprising;
a pointed driving projection on that end of said drive member facing the piston coaxially aligned with the expelling axis; and
a driven member carried by the piston, said driven member defining a conical bearing surface thereon opening toward said pointed driving projection and having an apex in registration with said expelling axis, said conical bearing surface angling away from said expelling axis with equal angles therearound so that said pointed driving projection engages said conical bearing surface in said apex to axially move said piston along said expelling axis with the force exerted on said piston by the drive member equally distributed circumferentially about said piston to prevent canting of said piston in said liquid chamber.
0 Assignments
0 Petitions
Accused Products
Abstract
Method and apparatus for injecting fluids into patients at a controlled rate from an ampule containing the injecting fluid with a sliding piston therein to force the fluid from the ampule into the patient using a drive system which incrementally and successively advances the piston in the ampule to meter the fluid into the patient.
-
Citations
1 Claim
-
1. In an apparatus for dispensing liquid including a liquid chamber with an outlet slidably mounting a piston therein for sliding movement axially along an expelling axis toward the outlet to force liquid from the outlet and a drive member movable axially along the expelling axis to engage and force the piston toward the outlet;
- the improvement comprising;
a pointed driving projection on that end of said drive member facing the piston coaxially aligned with the expelling axis; and
a driven member carried by the piston, said driven member defining a conical bearing surface thereon opening toward said pointed driving projection and having an apex in registration with said expelling axis, said conical bearing surface angling away from said expelling axis with equal angles therearound so that said pointed driving projection engages said conical bearing surface in said apex to axially move said piston along said expelling axis with the force exerted on said piston by the drive member equally distributed circumferentially about said piston to prevent canting of said piston in said liquid chamber.
- the improvement comprising;
Specification