Elastomeric connector coupling motor to cam actuator of infusion pump

• US 6,471,436 B1
• Filed: 06/19/1998
• Issued: 10/29/2002
• Est. Priority Date: 06/19/1998
• Status: Expired due to Fees

• Current Assignee: Hospira Incorporated (Pfizer Inc.)
• Original Assignee: Abbott Laboratories
• Inventors: Scherer, Andrew J., Lawless, Michael W., Gjata, John D., Squarcia, Stephanie R., Soberon, Peter A.
• Primary Examiner(s): Browne, Lynne H.
• Assistant Examiner(s): Cottingham, John R.
• Application Number:
  US09/100,621
• Time in Patent Office: 1,593 Days
• Field of Search: 403/305, 403/301, 403/300, 403/383, 403/359.6, 403/220, 403/221, 403/223, 403/228, 464/87, 464/88, 464/89
• US Class Current: 403/223
• CPC Class Codes: A61M 5/14224 Diaphragm type
• CPC Class Codes: F04B 17/03 driven by electric motors
• CPC Class Codes: F16D 3/74 the intermediate member or members being made of rubber or other rubber-like flexible material
• CPC Class Codes: Y10T 403/453 Flexible sleeve-type coupling
• CPC Class Codes: Y10T 403/458 Composite bushing with elastomeric component
• CPC Class Codes: Y10T 403/5733 Plural opposed sockets

Abstract

A drive connector for elastomerically coupling a drive shaft to a driven shaft. An elastomeric coupling includes openings on opposite ends that are generally “D”-shaped forming an interference fit with correspondingly shaped ends of the drive shaft and the driven shaft. A web extends transversely within the interior of the elastomeric coupling, limiting the distance that the drive shaft and driven shaft are inserted within the openings of the coupling. The coupling includes a rib that runs longitudinally along its outer length. A sleeve having a groove corresponding in size and shape to the rib is slipped over the coupling and is connected to the driven shaft. The sleeve includes a rigid interior element that is overmolded with an elastomeric material. A cam bearing is fitted over a cam surface on the sleeve and provides a force in one direction, urging a plunger to displace an elastomeric membrane in a pumping cassette, forcing medicinal fluid to flow through the pumping cassette. The elastomeric membrane provides the restoring force to the plunger, so that a loop formed on the upper portion of the plunger and disposed around the cam bearing does not receive any force from the cam bearing to move the plunger away from the pump cassette. The elastomeric coupling and sleeve form a relatively compact assembly for coupling the drive shaft to the driven shaft and accommodate minor misalignment between the center lines of the drive shaft and the driven shaft.

Claims

1. A resilient coupling assembly for transmitting a rotational drive force from a first shaft to a second shaft, comprising:

(a) a generally elongate elastomeric member having;

(i) a first orifice disposed at one end of the elastomeric member and sized to provide an interference fit over the first shaft; and

(ii) a second orifice disposed at an opposite end of the elastomeric member and sized to provide an interference fit over the second shaft; and

(b) an elongate sleeve having a central opening that is sized to provide an interference fit over an outer surface of the elastomeric member and providing a compressive force against the elastomeric member that retains the elastomeric member on at least one of the first and the second shafts, so that the shafts are coupled together through the elastomeric member;

wherein an outer surface of the sleeve comprises a cam surface having a profile that defines a locus of points at a varying radius about a central axis of the elastomeric member; and

(c) a link having a generally quadrilateral opening through which the sleeve extends, said link riding against the cam surface of the sleeve as the sleeve rotates.

2. The resilient coupling assembly of claim 1, wherein the elastomeric member includes a web that extends transversely and is disposed between the first orifice and the second orifice.

3. The resilient coupling assembly of claim 1, wherein at least one of the sleeve and the outer surface of the elastomeric member includes an alignment groove to key the position of the driven shaft.

4. The resilient coupling assembly of claim 3, wherein another of the sleeve and the outer surface of the elastomeric member includes an alignment ridge, sized to fit within the alignment groove, said alignment groove and alignment ridge cooperating together to provide the interference fit between the elastomeric member and the sleeve.

5. The resilient coupling assembly of claim 1, wherein the link is coupled to a plunger that is driven to move in a direction away from the sleeve as the cam surface rides against one side of the quadrilateral opening.

6. A resilient coupling assembly for transmitting a rotational drive force from a first shaft to a second shaft, comprising:

(a) a generally elongate elastomeric member having;

(i) a first orifice disposed at one end of the elastomeric member and sized to provide an interference fit over the first shaft; and

(ii) a second orifice disposed at an opposite end of the elastomeric member and sized to provide an interference fit over the second shaft; and

(b) an elongate sleeve having a central opening that is sized to provide an interference fit over an outer surface of the elastomeric member and providing a compressive force against the elastomeric member that retains the elastomeric member on at least one of the first and the second shafts, so that the shafts are coupled together through the elastomeric member, wherein the sleeve comprises an elastomeric material that is overmolded onto a rigid material.