Ambulatory infusion pump
First Claim
1. An ambulatory infusion pump comprisinga tubular housing for a fluid having an outlet aperture at a distal end for dispensing fluid into a conduit and an inner bore of predetermined diameter;
- a piston slidably mounted in said housing between a filled position and an empty position at said distal end to define a fluid-receiving chamber with said distal end;
a preloaded helical spring in said housing for imposing a decreasing biasing force on said piston to move said discharge fluid from said chamber and to maintain a decreasing pressure on the fluid in said chamber which varies no more than 15% of a nominal pressure during movement of said piston from said filled position to said empty position while effecting a continuous flow rate in the range of from 1 cc to 5 cc per hour;
a sleeve slidably mounted in a proximal end of said housing with said spring coiled about said sleeve for biasing said sleeve against said piston and toward said distal end of said housing; and
means for releasing said spring to impose said force on said piston.
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Accused Products
Abstract
The ambulatory infusion pump is provided with a preloaded spring having a fixed spring constant. A tab is provided to release the preloaded spring to impose a biasing force on the piston of the pump. The piston slides within the housing against a substantially constant friction force when moving from the filled position toward the empty position. The biasing force of the spring and the stroke of the piston are coordinated so as to maintain a pressure on the fluid being dispensed from the pump housing which decreases at a slow rate and within a range of about 15% of the referenced pressure.
91 Citations
22 Claims
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1. An ambulatory infusion pump comprising
a tubular housing for a fluid having an outlet aperture at a distal end for dispensing fluid into a conduit and an inner bore of predetermined diameter; -
a piston slidably mounted in said housing between a filled position and an empty position at said distal end to define a fluid-receiving chamber with said distal end; a preloaded helical spring in said housing for imposing a decreasing biasing force on said piston to move said discharge fluid from said chamber and to maintain a decreasing pressure on the fluid in said chamber which varies no more than 15% of a nominal pressure during movement of said piston from said filled position to said empty position while effecting a continuous flow rate in the range of from 1 cc to 5 cc per hour; a sleeve slidably mounted in a proximal end of said housing with said spring coiled about said sleeve for biasing said sleeve against said piston and toward said distal end of said housing; and means for releasing said spring to impose said force on said piston. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An ambulatory infusion pump comprising
a tubular housing for a fluid having an outlet aperture at a distal end for dispensing fluid into a conduit and an inner bore of predetermined diameter; -
a piston slidably mounted in said housing between a filled position and an empty position at said distal end to define a fluid-receiving chamber with said distal end; a preloaded helical spring in said housing for imposing a decreasing biasing force on said piston to move said fluid from said chamber to maintain a pressure on the fluid in said chamber which varied no more than 15% of a nominal pressure during movement of said piston from said filled position to said empty position; means for releasing said spring to impose said force on said piston; a sleeve slidably mounted in a proximal end of said housing with said spring coiled about said sleeve for biasing said sleeve against said piston and toward said distal end of said housing; and a shaft secured to said piston and slidably received in said sleeve.
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21. An ambulatory infusion pump comprising
a tubular housing for a fluid having an outlet aperture at a distal end for dispensing fluid into a conduit and an inner bore of predetermined diameter; -
a piston slidably mounted in said housing between a filled position and an empty position at said distal end to define a fluid-receiving chamber with said distal end; said bore having a diameter which increases in a direction towards said outlet aperture from said filled position to permit a decrease in friction force between said piston and said housing as said piston moves toward said empty position; a preloaded helical spring in said housing for imposing a decreasing biasing force on said piston to move said discharge fluid from said chamber to maintain a pressure on the fluid in said chamber which varies no more than 15% of a nominal pressure during movement of said piston from said filled position to said empty position; and means for releasing said spring to impose said force on said piston. - View Dependent Claims (22)
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Specification