INFUSION PUMP

BACKGROUND OF THE INVENTION

The present invention is directed to a door mount stabilization system and more particularly a door mount stabilization system for an infusion pump.

Door mount systems for infusion pumps are known in the art. As flow rates and demands for accuracy have increased, problems with the door mount system have resulted. More specifically, as the pump actuator force has increased, the pump chamber actuation force has been insufficient to counteract the actuator force resulting in cassette body movement during pumping with a plunger. When the cassette body moves, flow efficiency is lowered, fluid output volume varies, and limitations are created with respect to pump flow rates and low flow continuity. Therefore, a need exists in the art for a system that addresses these deficiencies.

An objective of the present invention is to provide a door mounting system that increases overall pump system stiffness .

Another objective of the present invention is to provide a door mount system that provides sufficient pump chamber rigidity to handle higher pump actuator forces.

A still further objective of the present invention is to provide a door mount system that increases flow efficiency, stabilizes output volumes, and allows for greater pump flow rates and continuity.

These and other objectives will be apparent to one of ordinary skill in the art based upon the following written description, drawings, and claims. BRIEF SUMMARY OF THE INVENTION

A door mount system having an infusion pump with a front mechanism plate. Pivotally connected to the pump is a door. Extending outwardly from the front mechanism plate are a plurality of mounting pins that align with and are received within openings in a front face of the door .

The pump has a moveable plunger that is connected to a ball screw that is operatively connected to a stepper motor. The mounting system provides sufficient strength and stability to handle increased plunger actuator force resulting in limited cassette movement within the door during pumping.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a partial side perspective view of a door mounting system;

Fig. 2 is a side sectional view of a door mounting system; and

Fig. 3 is a rear view of a door in a door mounting system.

Fig. 4 is a front view of a door in a door mounting, system.

Fig. 5 is a perspective view of a door in a door mounting system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the Figures, the door mount stabilization system 10 includes a door 12 formed to receive a fluid administration set 14 such as a cassette or the like. The door 12 is pivotally attached to an infusion pump 16 by a pivot pin 18. The pivot pin 18 extends through a pivot pin opening 20 in a mounting block 22 that is secured to the base formed therein that receives a portion of the fluid administration set 14.

The infusion pump 16 has a front mechanism plate 26.

Extending outwardly from the front mechanism plate 26 is a moveable plunger 28 that is aligned with and received by plunger opening 30. The plunger opening 30 has a centerline 31 that is coincident with the centerline of the cavity 25. Preferably, to improve flow performance of the pump 16, the plunger 28 is connected to a stepper motor 32 with a ball screw 34 that extends through a rotary nut 36, angular contact bearings 38, and a spacer 40 to a flexible coupler 42 that also receives a motor shaft 44. Such an arrangement actuates fluid in a gentle and smooth manner in order to keep flow laminar, keep pressure differentials to a minimum, minimize fluid shear stresses, and to smooth the flow profile.

Also, extending outwardly from the front mechanism plate 26 are first 46, second 48, and third 50 mounting pins. The mounting pins 46, 48, and 50 are positioned to align and be received by a first pin opening 52, a second pin opening 54, and a third pin opening 56 on a front face 58 of the door 12. Alternatively, the pins extend from the front face 58 of the door and are received by pin openings in the front mechanism plate 26. Preferably, the first and second pins 46 and 48 are positioned above the plunger opening 30, and the third pin 50 is located below the plunger opening 30.

In one embodiment, the first and second pins 46 and 48 are located an equal distance from the centerline 31 of the plunger opening 30 and cavity 25, but spaced in opposite directions from a vertical plane that includes the centerline 31. Preferably, the first pin 46 and second pin 48 are located an equal distance from the vertical plane through the centerline 31 on a horizontal line spaced above the plunger opening 30.

In another embodiment, the third pin 50 is located on a vertical line that extends through the centerline 31 of the plunger opening 30. Preferably, the third pin 50 is located the same distance from the centerline 31 of the plunger 30 and cavity 25 as the first and second pins 46 and 48.

Preferably, the depths of the pin openings 52, 54, and 56 with respect to the front face 58 of the door 12 are identical and the pins 46, 48, and 50 extend outwardly from the front mechanism plate 26 the same distance or length.

Alternatively, the pins 46, 48, and 50 can be of differing lengths and the corresponding openings 52, 54, and 56 can be constructed with corresponding depths to provide full

engagement.

The free ends of the three pins 46, 48, and 50 engage the bottom of the pin openings 52, 54, and 56 to provide increased stiffness and even load distribution to support a cassette 14 during the pumping cycle. The stiffness is maintained in a flow range between 0.1 ml/hr to 2,000 ml/hr. The large dynamic range is achieved through use of fine motor control movements and reduced mechanical compliance. To achieve the dynamic range the pump chamber reaction force to the pump actuator force requires a 5 to 1 ratio.

In operation, the pivot pin 18 is inserted through the pivot pin opening 20 in mounting block 22 and through an opening 60 in the bottom of the door 12. The door 12 is pivoted to a closed position such that pins 46, 48, and 50 are received within openings 52, 54, and 56. Door lock 62 is engaged to maintain door 12 in a closed position. Once locked, motor 32 is activated causing plunger 28 to engage cassette 14 causing fluid to flow. Thus a door mount stabilization system has been disclosed that, at the very least, meets all the stated objectives.