Peristaltic pump

1. A pump assembly for use in pumping a viscous material through a pumping tube which can be engage by the pump assembly, the pump assembly comprising;

a pump body;

a rotor rotatably retained on the pump body; the rotor having a pair of plates for operatively retaining a plurality of rollers therebetween, the plates having generally rectangular shape and having rounded corners extending sufficiently to generally cover ends of the corresponding rollers retained between the plates and to support the rollers;

a stator pivotably retained on the pump body;

a lever arm operatively retained on the pump body;

a cam assembly associated with the lever arm and the stator for use in engaging the stator to move the stator to an engaged position engaging a pumping tube between the rotor and the stator, and for use in disengaging the pumping tube from between the rotor and the stator; and

the stator being pivotably retained on the pump body at a single pivot point and pivoting at that pivot point spaced from a rotation point of the rotor, the lever arm being movable relative to a fixed rotation axis on the pump body and spaced from the pivot point and the rotation point for engaging and disengaging the stator, the lever arm including a portion extending over a portion of the tube engaged between the stator and rotor in the engaged position.

2. The pump assembly of claim 1 , further comprising the stator being pivotably retained on an upper portion of the pump body.

3. The pump assembly of claim 2 , further comprising the cam assembly being movable relative to the fixed rotation axis and generally between the pivot point and the fixed rotation axis.

4. The pump assembly of claim 1 , wherein in a first plane defined relative to the pump body the lever arm fixed rotation axis is located distal from pivot point of stator and the rotation point of rotor is positioned between the pivot point and the fixed rotation axis.

5. The pump assembly of claim 4 , further comprising the cam assembly being movable relative to the fixed rotation axis and generally in an area between the fixed rotation axis and both of the pivot point and the rotation point.

6. The pump assembly of claim 4 , further comprising the cam assembly movable relative to the to the fixed rotation axis and spaced distal from the pivot point and positioned generally closer to the fixed rotation axis than the pivot point.

7. The pump assembly of claim 2 , wherein in a second plane defined relative to the pump body the lever arm fixed rotation axis is located distal from the pivot point of the stator and the pivot point of the stator is positioned between the rotation point and the fixed rotation axis.

8. The pump assembly of claim 7 , further comprising the cam assembly being movable relative to the fixed rotation axis and generally in an area between the fixed rotation axis and both the pivot point and the rotation point.

9. The pump assembly of claim 7 , further comprising the cam assembly movable relative to the to the fixed rotation axis and spaced distal from the pivot point and positioned generally closer to the fixed rotation axis than the pivot point.

10. The pump assembly of claim 1 , further comprising the stator being pivotably retained on an upper portion of the pump body;

in a first plane defined relative to the pump body the lever arm fixed rotation axis is located distal from pivot point of the stator and the rotation point of rotor is positioned between the pivot point and the fixed rotation axis, and

in a second plane defined relative to the pump body the lever arm fixed rotation axis is located distal from the pivot point of the stator and the pivot point of the stator is positioned between the rotation point and the fixed rotation axis.

11. The pump assembly of claim 10 , further comprising the cam assembly being movable relative to the fixed rotation axis and generally in an area between the fixed rotation axis and both of the pivot point and the rotation point.

12. The pump assembly of claim 10 , further comprising the cam assembly movable relative to the to the fixed rotation axis and spaced distal from the pivot point and positioned generally closer to the fixed rotation axis than the pivot point.

13. The pump assembly of claim 10 , further comprising the cam assembly movable relative to the to the fixed rotation axis and generally between the pivot point and the fixed rotation axis.

14. The pump assembly of claim 1 , further comprising the stator being pivotably retained on a lower portion of the pump body;

in a first plane defined relative to the pump body the lever arm fixed rotation axis is located distal from pivot point of stator and the rotation point of rotor is positioned between the pivot point and the fixed rotation axis, and

in a second plane defined relative to the pump body the lever arm fixed rotation axis is located distal from the pivot point of the stator and the pivot point of the stator is positioned generally between the rotation point and the fixed rotation axis.

15. The pump assembly of claim 1 , further comprising a detent on the assembly for receiving and retaining the lever arm in a closed position when the lever arm is rotated to engage the stator towards the rotor.

16. The pump assembly of claim 1 , further comprising captive retaining fasteners carried on pump body for engagement with a housing to which the pump assembly is attached for use.

17. A beverage dispenser including at least one modular pump assembly for use in pumping a viscous material through a pumping tube which can be engage by the pump assembly, the modular pump assembly comprising;

a pump body retained in the beverage dispenser;

a rotor rotatably retained on the pump body; the rotor having a pair of plates for operatively retaining a plurality of rollers therebetween, the plates having generally rectangular shape and having rounded corners extending sufficiently to generally cover ends of the corresponding rollers retained between the plates and to support the rollers;

a stator pivotably retained on the pump body;

a lever arm operatively retained on the pump body;

the pumping tube extending from a beverage material source, the pumping tube extending in a compressible condition between opposing portions of the stator and rotor;

a cam assembly associated with the lever arm and the stator for use in engaging the stator to move the stator to engage the pumping tube between the rotor and the stator, and for use in disengaging the pumping tube from between the rotor and the stator; and

the stator being operatively retained on the pump body at a single pivot point and pivoting at that pivot point spaced from a rotation point of the rotor, the lever arm being movable relative to a fixed rotation axis and spaced from the pivot point and the rotation point for engaging and disengaging the stator, the lever arm including a pivot end and a distal end with the distal end having a protrusion engaging a stop when the pumping tube is engaged between the rotor and the stator.

18. A pump assembly for use in pumping a viscous material through a pumping tube which can be engage by the pump assembly, the pump assembly comprising;

a pump body;

a rotor rotatably retained on the pump body; the rotor having a plurality of rollers;

a stator pivotably retained on the pump body; the stator and rollers defining a path for a pumping portion of the tube;

a lever arm operatively retained on the pump body;

a cam assembly associated with the lever arm and the stator for use in engaging the stator to move the stator to engage the pumping tube between the rotor and the stator in an engaged position, and for use in disengaging the pumping tube from between the rotor and the stator to achieve a disengaged position, the lever arm extending adjacent but not across the tube in the disengaged position and the lever arm extending across the tube in the engaged position;

the stator being operatively retained on an upper portion of the pump body at a single pivot point and pivoting generally downwardly at that pivot point spaced from a rotation point of the rotor, the lever arm being movable relative to a fixed rotation axis and spaced from the pivot point and the rotation point for engaging and disengaging the stator;

in a first plane the lever arm fixed rotation axis and the pivot point of the stator are located on one side of the path and the rotation point of the rotor is positioned on one an opposite side of the path;

a cam assembly movable relative to the fixed rotation axis and generally in an area between the fixed rotation axis and both of the pivot point and the rotation point, and the cam assembly movable relative to the to the fixed rotation axis and spaced distal from the pivot point and generally closer to the fixed rotation axis than the pivot point.

19. The pump assembly of claim 1 wherein the handle is operable to retain the stator out of engagement with the tube.

20. The pump assembly of claim 1 wherein the handle and cam structures provide an over center positive stop when the tube is engaged between the stator and rotor.

21. The pump assembly of claim 1 wherein the handle and cam structures provide an over center positive stop when the tube is disengaged from the stator and rotor.