Peristaltic pump having improved pumping fingers
A pumping finger subassembly for a peristaltic infusion pump has a housing, a pinch member, a block member, and at least one biasing spring. The housing includes a transverse slot, a first side wall, and an open second side through which the pinch member and biasing spring(s) are inserted into the transverse slot. The block member includes a foot portion and a side wall portion. The foot portion is insertable into the housing through the open second side such that the block member is constrained against movement relative to the housing and the side wall portion of the block member opposes the first side wall of the housing, whereby the pinch member is supported on both lateral sides to prevent tilting of the pinch member.
1. A pumping finger subassembly for a peristaltic infusion pump, the pumping finger subassembly comprising:
a housing including a base, a leading wall, a trailing wall, and a first side wall arranged with respect to one another to define a transverse slot, wherein the transverse slot is open through an upper opening of the housing opposite the base and through a second side opening of the housing opposite the first side wall;
a pinch member received by the housing though the second side opening, the pinch member including a pedestal portion and a tip portion extending upwardly from the pedestal portion;
a block member separate from the pinch member and from the housing, the block member being received by the housing though the second side opening, the block member including a foot portion and a side wall portion extending upwardly from the foot portion, wherein the side wall portion of the block member closes at least a portion of the second side opening of the housing and the side wall portion of the block member does not protrude from the housing; and
at least one spring arranged to act between the foot portion of the block member and the pedestal portion of the pinch member to bias the pinch member in a direction causing the tip portion of the pinch member to protrude from the housing through the upper opening of the housing.
2. The pumping finger subassembly according to claim 1 , wherein the block member includes an external abutment surface arranged to abut with an internal surface of the housing adjacent to the second side opening to limit displacement of the block member relative to the housing in a lateral direction away from the first side wall of the housing.
3. The pumping finger subassembly according to claim 2 , wherein the abutment surface is on the foot portion of the block member.
4. The pumping finger subassembly according to claim 1 , wherein the side wall portion of the block member includes at least one upwardly facing shoulder arranged to abut with a downwardly facing surface of the housing to limit displacement of the block member relative to the housing in an upward direction away from the base of the housing.
5. The pumping finger subassembly according to claim 4 , wherein the downwardly facing surface of the housing borders the second side opening.
6. The pumping finger subassembly according to claim 1 , wherein the block member includes a downwardly facing surface arranged to abut with an upwardly facing surface of the housing to limit displacement of the block member relative to the housing in a downward direction toward the base of the housing.
7. The pumping finger subassembly according to claim 6 , wherein the downwardly facing surface of the block member is on the side wall portion of the block member.
8. The pumping finger subassembly according to claim 6 , wherein the upwardly facing surface of the housing borders the second side opening.
9. An infusion pump operable to pump fluid through a tubing segment of an administration set received by the infusion pump, the infusion pump comprising:
a plurality of pumping finger subassemblies according to claim 1 ;
a platen surface opposite the plurality of pumping finger subassemblies, wherein the tubing segment is positioned between the plurality of pumping finger subassemblies and the platen surface when the administration set is loaded in the pump; and
a pumping mechanism operable to displace the plurality of pumping finger subassemblies relative to the platen surface to reversibly deform the tubing segment to pump fluid through the tubing segment.