Drug delivery system
First Claim
1. System for delivering a drug to a patient including a reservoir for storing the drug to be delivered to the patient by the system and a plunger assembly reciprocally received in the reservoir for forcing the drug to the patient from the reservoir when advanced into the reservoir, with the plunger assembly having a free end, comprising, in combination:
- a chassis;
a lead screw having a first end;
means for mounting the lead screw for rotation and at least limited axial movement from a first axial position with respect to the chassis;
a motor having an output shaft;
means for rotatably relating the output shaft of the motor with the lead screw for rotating the lead screw with respect to the chassis;
a drive nut threadably received on the lead screw and removeably attached in a nonrotatable manner to the free end of the plunger assembly for advancing the plunger assembly in the reservoir in response to the rotation of the lead screw by the motor and the rotatably relating means; and
switch means actuated by the first end of the lead screw for electrically interrupting the operation of the motor when the lead screw is moved into its first axial position as the result of an increase of force necessary to advance the plunger assembly into the reservoir due to excessive reservoir back pressure caused by occlusion, plunger assembly friction, a depleted reservoir, and like conditions, with the switch means including means for axially biasing the lead screw with respect to the chassis out of its first axial position and in the direction of axial movement of the plunger assembly for advancing the plunger assembly into the reservoir for forcing the drug from the reservoir.
3 Assignments
0 Petitions
Accused Products
Abstract
A system for delivering a drug to a patient according to the preferred embodiment of the present invention is shown as including a plunger assembly reciprocally received in a reservoir for forcing the drug therefrom for delivery to the patient. The plunger assembly is axially advanced by the rotation of a lead screw rotatably mounted and axially movable with respect to the chassis. In a first axial position, the end of the lead screw deflects contacts of a switch member into electrical engagement which interrupts operation of the motor which rotates the lead screw. The lead screw is biased out of its first axial position such that the first end of the lead screw does not actuate the switch member and rotation of the lead screw is not interrupted. An increase in the force necessary to advance the plunger assembly into the reservoir due to excessive reservoir back pressure caused by occlusion, plunger assembly friction, a depleted reservoir, and like conditions will cause the lead screw to move into its first axial position against its bias and to actuate the switch member.
290 Citations
31 Claims
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1. System for delivering a drug to a patient including a reservoir for storing the drug to be delivered to the patient by the system and a plunger assembly reciprocally received in the reservoir for forcing the drug to the patient from the reservoir when advanced into the reservoir, with the plunger assembly having a free end, comprising, in combination:
- a chassis;
a lead screw having a first end;
means for mounting the lead screw for rotation and at least limited axial movement from a first axial position with respect to the chassis;
a motor having an output shaft;
means for rotatably relating the output shaft of the motor with the lead screw for rotating the lead screw with respect to the chassis;
a drive nut threadably received on the lead screw and removeably attached in a nonrotatable manner to the free end of the plunger assembly for advancing the plunger assembly in the reservoir in response to the rotation of the lead screw by the motor and the rotatably relating means; and
switch means actuated by the first end of the lead screw for electrically interrupting the operation of the motor when the lead screw is moved into its first axial position as the result of an increase of force necessary to advance the plunger assembly into the reservoir due to excessive reservoir back pressure caused by occlusion, plunger assembly friction, a depleted reservoir, and like conditions, with the switch means including means for axially biasing the lead screw with respect to the chassis out of its first axial position and in the direction of axial movement of the plunger assembly for advancing the plunger assembly into the reservoir for forcing the drug from the reservoir. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- a chassis;
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10. System for delivering a drug to a patient including a reservoir for storing the drug to be delivered to the patient by the system and a plunger assembly reciprocally received in the reservoir for forcing the drug to the patient from the reservoir when advanced into the reservoir comprising, in combination:
- a chassis;
a lead screw having a first end;
means for mounting the lead screw for rotation and at least limited axial movement from a first axial position with respect to the chassis, with the lead screw being axially biased with respect to the chassis out of its first axial position and in the direction of axial movement of the plunger assembly for advancing the plunger assembly into the reservoir for forcing the drug from the reservoir;
means for rotating the lead screw with respect to the chassis;
means for axially advancing the plunger assembly with respect to the reservoir acting in cooperation with the lead screw and its rotation produced by the rotating means; and
means actuated by the first end of the lead screw for interrupting the operation of the rotating means when the lead screw is moved into its first axial position against the bias of the lead screw as the result of an increase of force necessary to advance the plunger assembly into the reservoir due to excessive reservoir back pressure caused by occlusion, plunger assembly friction, a depleted reservoir, and like conditions. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
- a chassis;
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21. In a system for delivering a drug to a patient including a reservoir for storing the drug to be delivered to the patient by the system and a plunger assembly reciprocally received in the reservoir for forcing the drug to the patient from the reservoir when advanced into the reservoir, a chassis, and means for axially advancing the plunger assembly into the reservoir, with the axially advancing means having a first end mounted for at least limited axial movement from a first axial position with respect to the chassis, with the improvement comprising switch means actuated by the first end of the axially advancing means for electrically interrupting the axially advancing means comprising, in combination:
- a first contact held in a spaced relation from the chassis; and
a second, spring contact in a normally spaced condition from the first contact, with the first end of the axially advancing means abutting with the second, spring contact in its first axial position and moving the second, spring contact to electrically engage the first contact, with the second, spring contact axially biasing the axially advancing means with respect to the chassis out of its first axial position and in the direction of axial movement of the plunger assembly for advancing the plunger assembly into the reservoir for forcing the drug from the reservoir, with the switch means electrically interrupting the axially advancing means when the first end is moved into its first axial position against the bias of the second, spring contact as the result of an increase of force necessary to advance the plunger assembly into the reservoir due to excessive reservoir back pressure caused by occlusion, plunger assembly friction, a depleted reservoir, and like conditions. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
- a first contact held in a spaced relation from the chassis; and
Specification