Infusion pumps and dosage control means therefor
First Claim
1. In an infusion pump for delivering a metered amount of a drug, cylindrical barrel means adapted to receive a quantity of the drug, the barrel means having an open rear end for receiving the front end of a plunger and further having an opening in a forward wall thereof through which the drug can be ejected upon a forward movement of the plunger in the barrel means, the barrel means comprising, in combination, a thin-walled, relatively compliant cylindrical syringe adapted to receive the plunger and having a nominal outer diameter, a cylindrical clamping member axially coextensive with and radially positionable coaxially over the syringe, the inner diameter of the clamping member being adjustable inwardly to an inner limit representing a fixed standard inner diameter smaller than the nominal outer diameter of the syringe, and means for releasably applying an inwardly directed radial clamping force to the clamping member to deform the wall of the syringe into conformance with the standard inner diameter of the clamping member, whereby the syringe forms an intimately adhering liner for the clamping member.
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Accused Products
Abstract
An infusion pump suitable, e.g., for delivering an adjustable, metered amount of a drug to a patient includes a pre-sterilized, thin-walled plastic syringe which is employed solely as a sterile inner liner for an outer, thick-walled split cylindrical clamp that is axially coextensive with the plastic syringe barrel. The required effect is obtained by inwardly squeezing the clamp against the wall of the plastic syringe until the two parts of the clamp come together to define a bore of a standard inner diameter. A plunger, which is tightly engaged with the wall of the so-deformed plastic syringe to prevent leakage of the drug, is normally driven at one of a plurality of selectable speeds by means of a gear box that is specially constructed to vary the plunger speed travel, and thereby the fluid flow rate of the drug in the syringe, in successive steps with each step being a predetermined constant fraction of the next-preceeding step. Facilities are also provided for introducing a one-shot increase in dosage into the so-selected fluid flow rate without interrupting such flow rate.
34 Citations
18 Claims
- 1. In an infusion pump for delivering a metered amount of a drug, cylindrical barrel means adapted to receive a quantity of the drug, the barrel means having an open rear end for receiving the front end of a plunger and further having an opening in a forward wall thereof through which the drug can be ejected upon a forward movement of the plunger in the barrel means, the barrel means comprising, in combination, a thin-walled, relatively compliant cylindrical syringe adapted to receive the plunger and having a nominal outer diameter, a cylindrical clamping member axially coextensive with and radially positionable coaxially over the syringe, the inner diameter of the clamping member being adjustable inwardly to an inner limit representing a fixed standard inner diameter smaller than the nominal outer diameter of the syringe, and means for releasably applying an inwardly directed radial clamping force to the clamping member to deform the wall of the syringe into conformance with the standard inner diameter of the clamping member, whereby the syringe forms an intimately adhering liner for the clamping member.
Specification