US 5,800,405 A · Syringe actuation device

Abstract

A syringe actuation device includes a housing containing a spring-biased piston that applies an actuation force to a syringe plunger inserted into the housing. A pivoting mechanism causes the piston to pivot with respect to the longitudinal axis of the housing as the piston moves along that axis to actuate the plunger, whereby the axially-directed component of the force applied by the piston to the plunger remains substantially constant throughout the stroke of the piston. In one embodiment, the device comprises an internally-threaded outer sleeve having a longitudinal opening for receiving a pre-filled syringe with an extended plunger and a distal opening through which the syringe barrel extends, and an externally-threaded cylinder, containing the piston, that threads into the proximal end of the sleeve so as to bring the piston to bear against the plunger. The pivoting mechanism comprises a tapered internal diameter of the cylinder, and a sloped spring seat on the piston. In another embodiment, the device comprises a housing that contains a piston biased by a pair of springs, and a sleeve that receives a syringe barrel, with the plunger of the syringe extending from the proximal end of the sleeve. The proximal end of the sleeve is inserted into the housing through an opening in the distal end wall of the housing, so that the plunger seats against the piston. The pivoting mechanism comprises a narrowing internal housing width and springs of unequal spring constant and/or length.

Claims51

Dependent claims

A device for applying an axially-directed actuation force to a syringe plunger, of the type including a force-applying mechanism engageable with the plunger to apply the actuation force thereto, characterized by the force applying mechanism having a first position at which the magnitude of the total force applied to the plunger is at a maximum value but the axially-directed actuation force is less than the total force applied to the plunger, and a second position at which the magnitude of the total force applied to the plunger is less than its maximum value and the axially-directed force is approximately equal to the total force applied to the plunger, wherein the force-applying mechanism comprises:

a housing having a proximal end and a distal end with an opening dimensioned to receive the plunger;
a piston disposed for longitudinal movement within the housing between a proximal position and a distal position, the piston being seatable against the plunger when the plunger is received in the housing through the opening in the distal end;
first and second springs disposed between the piston and the proximal end of the housing so as to bias the piston toward its distal position;
and
pivoting means, operative on the piston, for canting the piston with respect to the longitudinal axis of the housing when the piston is in its proximal position, and for causing the piston to pivot as it moves toward its distal position until the piston is oriented substantially coaxially with the longitudinal axis when the piston is at its distal position.

2 more elements

A device for actuating a syringe, wherein the syringe includes a barrel and a plunger movable axially within the barrel, the device comprising:

a housing having a closed proximal end and a distal end with an opening therein dimensioned to receive the plunger;
a retention element extending into the housing from the distal end opening;
a piston disposed for longitudinal movement within the housing between a proximal position and a distal position, the piston having a proximal end and an open distal end dimensioned to slidingly receive the retention element when the piston is in its distal position;
first and second springs disposed within the housing between the piston and the proximal end of the housing so as to bias the piston toward its distal position;
and
an externally-threaded sleeve internally dimensioned to receive a syringe and externally dimensioned to be received within the opening in the distal end of the housing and selectively threaded into and out of the retention element, the sleeve having an open proximal end through which the plunger of the syringe extends when a syringe is installed in the sleeve;
whereby, when the sleeve is threaded into the retention element through the opening in the distal end of the housing with a syringe installed in the sleeve and the plunger of the syringe extending proximally through the open proximal end of the sleeve, the plunger of the syringe bears against the proximal end of the piston so as to urge the piston toward its proximal position.

4 more elements

Dependencies are inferred from the claim text.

Syringe actuation device

Life of this patent

Syringe actuation device

Life of this patent

Abstract

Claims51