Overfill protection systems for implantable drug delivery devices
First Claim
1. An implantable drug delivery device comprising:
- a) a housing;
b) a reservoir disposed within the housing for storing a supply of fluid and including a surface that moves a first distance as the reservoir collapses from a full position to a refill position;
c) a refill port, formed in the housing, for receiving said fluid;
d) a refill passage in the housing for conveying fluid from the refill port to the reservoir;
e) a valve for selectively occluding the refill passage; and
f) means for moving the valve a second distance in response to movement of the reservoir surface, the second distance being less than the first distance.
3 Assignments
0 Petitions
Accused Products
Abstract
The displacement of refill valves in an implantable drug delivery device is reduced to permit the housings of a drug delivery device to remain compact in size while permitting reservoirs of increased depth to be used. In a preferred embodiment, a collapsible link is provided as a telescoping member incorporating a coil spring. As the valve is pulled into contact with its seat, a detectable pressure increase is sensed in the refill device. In accordance with the invention, as the drug supply contained in the reservoir depletes, the reservoir surface moves towards a collapsed position, compressing the coil spring and eventually contacting the valve stem, thereby lifting the valve from its seat. By virtue of telescoping link, the valve stem length and therefore the valve travel may be reduced as compared to prior art devices, thus eliminating the need for increased housing depth when deeper reservoirs are used. The collapsible link may be comprised of a second spring combined with a telescoping link. The second spring is situated on a side of the valve opposite the telescoping link, thereby providing a downward force on the valve and valve stem. As an other alternative, the invention provides a lever arm for actuating the refill valve. A pivot for the lever arm is situated near the refill valve and a distal end of the lever arm maintained in contact with the reservoir surface using a spring bias. An intermediate portion of the lever arm engages the valve stem. Thus, as the reservoir surface moves towards the collapsed position, the displacement of the valve is a fraction of the displacement of the distal end of the lever arm.
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Citations
24 Claims
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1. An implantable drug delivery device comprising:
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a) a housing;
b) a reservoir disposed within the housing for storing a supply of fluid and including a surface that moves a first distance as the reservoir collapses from a full position to a refill position;
c) a refill port, formed in the housing, for receiving said fluid;
d) a refill passage in the housing for conveying fluid from the refill port to the reservoir;
e) a valve for selectively occluding the refill passage; and
f) means for moving the valve a second distance in response to movement of the reservoir surface, the second distance being less than the first distance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 23)
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12. An implantable drug delivery device comprising:
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a) a housing;
b) a reservoir disposed within the housing for storing a supply of fluid and including a surface that moves as the reservoir collapses from a full position to a refill position;
c) a refill port, formed in the housing, for receiving said fluid;
d) a refill passage in the housing for conveying fluid from the refill port to the reservoir;
e) a valve for selectively occluding the refill passage; and
f) a link operatively connecting the valve to the reservoir surface such that the displacement of the valve is less than the displacement of the reservoir surface. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 24)
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Specification