Syringe pump bearing mechanism
First Claim
1. A syringe pump having a lead screw with a drive device in threaded engagement with the lead screw, the drive device moving along the lead screw in response to rotation of the lead screw, and a drive head adapted to drive a syringe plunger into the barrel of a syringe to expel fluid contents of the syringe, the syringe pump comprising:
- a lead screw having a first end and a second end with the first end mounted to a frame, the second end of the lead screw comprises a bearing mount having outwardly diverging bearing surfaces;
a connection tube located over the lead screw and connected between the drive device and the drive head to communicate movement of the drive device along the lead screw to the drive head, the connection tube having a hollow portion with an inner surface;
wherein the second end of the lead screw is located within the hollow portion of the connection tube but is otherwise unmounted; and
a bearing located at the bearing mount in contact with the inner surface of the hollow portion of the connection tube thereby creating a guided cantilever mount of the second end of the lead screw within the connection tube.
5 Assignments
0 Petitions
Accused Products
Abstract
A lead screw mounting system for a syringe pump in which a second end of a lead screw is located within a connection tube that connects a drive device engaged with the lead screw to a plunger drive head. A bearing mount having diverging bearing surfaces is formed at the second end of the lead screw and a bearing having a complementary inner shape is mounted to the bearing mount. The bearing is larger than the inner diameter of the connection tube and is in constant contact with the tube. During operation, the bearing tends to move up one or the other of the diverging bearing surfaces of the bearing mount depending on which direction the connection tube is moving over the bearing creating a wedge action. The bearing functions to keep the lead screw concentrically located within the connection tube thereby increasing flow uniformity of the syringe pump.
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Citations
37 Claims
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1. A syringe pump having a lead screw with a drive device in threaded engagement with the lead screw, the drive device moving along the lead screw in response to rotation of the lead screw, and a drive head adapted to drive a syringe plunger into the barrel of a syringe to expel fluid contents of the syringe, the syringe pump comprising:
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a lead screw having a first end and a second end with the first end mounted to a frame, the second end of the lead screw comprises a bearing mount having outwardly diverging bearing surfaces; a connection tube located over the lead screw and connected between the drive device and the drive head to communicate movement of the drive device along the lead screw to the drive head, the connection tube having a hollow portion with an inner surface; wherein the second end of the lead screw is located within the hollow portion of the connection tube but is otherwise unmounted; and a bearing located at the bearing mount in contact with the inner surface of the hollow portion of the connection tube thereby creating a guided cantilever mount of the second end of the lead screw within the connection tube. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A syringe pump having a lead screw with a drive device in threaded engagement with the lead screw, the drive device moving along the lead screw in response to rotation of the lead screw, and a drive head adapted to drive a syringe plunger into the barrel of a syringe to expel fluid contents of the syringe, the syringe pump comprising:
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a lead screw having a first end and a second end with the first end mounted to a frame; a connection tube located over the lead screw and connected between the drive device and the drive head to communicate movement of the drive device along the lead screw to the drive head, the connection tube having a hollow portion with an inner surface; wherein the second end of the lead screw is located within the hollow portion of the connection tube but is otherwise unmounted; and a bearing located at the second end of the lead screw in contact with the inner surface of the hollow portion of the connection tube thereby creating a guided cantilever mount of the second end of the lead screw within the connection tube; wherein the bearing has a larger outer diameter than the inner diameter of the hollow portion of the connection tube within which it is mounted, the bearing having a discontinuity that permits the bearing to compress to thereby be mounted within the connection tube. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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22. A syringe pump having a lead screw, a nut device engaged with the lead screw that moves along the lead screw in response to rotation of the lead screw, and a drive head adapted to drive a syringe plunger into a syringe barrel, the syringe pump comprising:
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a hollow connection tube located over the lead screw and connected between the nut device and the drive head such that movement of the nut device along the lead screw is communicated by the connection tube to the drive head, the connection tube having an inner surface; wherein the lead screw is mounted at a first end to a frame; wherein a second end of the lead screw is continuously located within the hollow connection tube and comprises a bearing mount having outwardly diverging bearing surfaces; and a bearing located at the bearing mount, the bearing configured to engage the bearing surfaces of the bearing mount and the inner surface of the connection tube so as to centrally locate the second end of the lead screw in the connection tube during movement of the connection tube along the lead screw. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
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31. A lead screw mounting system for use in a syringe pump having a drive head adapted to drive a syringe plunger into the barrel of a syringe to expel fluid from the barrel, the lead screw mounting system comprising:
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a lead screw mounted at a first end to a frame; a nut device engaged with the lead screw that moves along the lead screw in response to rotation of the lead screw; a hollow connection tube located over the lead screw and connected between the nut device and the drive head such that movement of the nut device causes movement of the connection tube over the lead screw and causes movement of the drive head, the connection tube having an inner surface; wherein a second end of the lead screw is continuously located within the hollow of the connection tube; wherein the second end of the lead screw comprises a bearing mount; and a bearing located at the bearing mount, the bearing having at least one tapered inner surface engaging the bearing mount and an outer surface engaging the inner surface of the connection tube so as to centrally locate the second end of the lead screw in the connection tube during movement of the connection tube along the lead screw. - View Dependent Claims (32, 33, 34, 35, 36, 37)
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Specification