Fluid infusion pump capable of detecting erroneous tube displacement
First Claim
1. A peristaltic fluid infusion pump having a main body and a cover securable to said main body, adapted to sandwich, between said main body and said cover, a flexible tube which is placed on a wall of said main body;
- wherein said main body is formed with a generally semi-cylindrical groove for receiving said flexible tube;
said cover is formed with a recess which encloses a spring and with a pressure plate which is urged by said spring toward said groove in said main body whenever said cover is closed;
further comprising a plurality of fingers slidably received in a cavity formed in the wall and so aligned that respective fore end portions of said fingers sequentially engage respective axially adjacent portions of said flexible tube to compress said tube and to thereby transfer any medication fluid inside the tube longitudinally through said tube; and
a pressure detector located adjacent said tube, on a surface of said pressure plate within a range of area in which the fore end portions of the fingers press the tube, said pressure plate being located on a side of said tube opposite said fingers and being urged, by said spring, toward the fingers against a pressure exerted by the fingers via the tube;
said pressure detector detecting the pressure exerted from each of the fingers via the tube, the pressure plate, and the spring, and outputting at least one detection signal representing said pressure.
1 Assignment
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Accused Products
Abstract
A pressure sensor 16 has a length C and a width D identical respectively to a length A and a width B of a fluid pumping section 11 and is provided in a portion of a cover 15 opposite to the fluid pumping section 11. The fluid pumping section 11 has a structure for pressing a tube placed in a groove 13 by means of fingers which advance and retract in a cavity 14 formed in a wall 12 of a main body. A possible erroneous placement of the tube is detected according to a change of pressure force exerted from each of the fingers, detected by the pressure sensor 16 . The pressure sensor 16, which is provided within a range in which the fingers can press the tube, can detect even a slight displacement, of the tube from the range in which the fingers can press the tube, to thereby allow detection of erroneous tube placement free of a dead zone to be achieved.
124 Citations
16 Claims
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1. A peristaltic fluid infusion pump having a main body and a cover securable to said main body, adapted to sandwich, between said main body and said cover, a flexible tube which is placed on a wall of said main body;
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wherein said main body is formed with a generally semi-cylindrical groove for receiving said flexible tube; said cover is formed with a recess which encloses a spring and with a pressure plate which is urged by said spring toward said groove in said main body whenever said cover is closed; further comprising a plurality of fingers slidably received in a cavity formed in the wall and so aligned that respective fore end portions of said fingers sequentially engage respective axially adjacent portions of said flexible tube to compress said tube and to thereby transfer any medication fluid inside the tube longitudinally through said tube; and a pressure detector located adjacent said tube, on a surface of said pressure plate within a range of area in which the fore end portions of the fingers press the tube, said pressure plate being located on a side of said tube opposite said fingers and being urged, by said spring, toward the fingers against a pressure exerted by the fingers via the tube; said pressure detector detecting the pressure exerted from each of the fingers via the tube, the pressure plate, and the spring, and outputting at least one detection signal representing said pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A fluid infusion pump, having a main body and a cover securable to said main body, adapted to sandwich, between said main body and said cover, a flexible tube which is placed on a wall of said main body;
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wherein said main body is formed with a generally semi-cylindrical groove for receiving said flexible tube; said cover is formed with a recess which encloses a spring and a pressure plate which is urged by said spring toward said groove in said main body whenever said cover is closed; further comprising a plurality of fingers slidably received in a cavity formed in the wall and so aligned that respective fore end portions of said fingers sequentially engage respective axially adjacent portions of said flexible tube to compress said tube and to thereby transfer any medication fluid inside the tube longitudinally through said tube; a motor which drives said fingers via respective cams; a slit disk, mounted on a common shaft with said motor, and formed with a plurality of slits of differing circumferential length; a photosensor which detects light travelling through any of the slits of the slit disk and outputs a detection signal; a rotational position detector, coupled to an output of said photosensor, which determines rotational position of said motor, based upon said photosensor detection signal, said detector including a timer which measures a time interval between successive inversions of said detection signal and a table associating specific slits with respective time intervals; and a pressure detector located adjacent said tube, on a surface of said pressure plate within a range of area in which the fore end portions of the fingers press the tube, detecting the pressure exerted from each of the fingers via the tube, the pressure plate, and the spring, and outputting at least one detection signal representing said pressure; wherein the motor is a stepping motor, and the fluid infusion pump further comprises; motor initial driving means driving the stepping motor, until an edge of a next slit of the slit disk reaches a position in the vicinity of the photosensor, by supplying a specified number of pulses, having a duty ratio set by a predetermined method, to the stepping motor, according to the rotational position of the stepping motor detected by the rotational position detector; duty ratio setting means setting the duty ratio, of the drive pulses to be supplied to the stepping motor located in a rotational position such that the edge of the next slit of the slit disk reaches a position in the vicinity of the photosensor, at a stationary duty ratio at which a minimum current, assuring a stationary torque, is achieved by a predetermined method, according to the rotational position of the stepping motor, and thereafter setting the duty ratio of the drive pulses at a duty ratio at which a necessary minimum drive current, in a present rotational position, is achieved by successively supplying, to the stepping motor, drive pulses having a duty ratio obtained by gradually increasing the set stationary duty ratio, until the detection signal from the photosensor is inverted in level; and motor driving means, driving the stepping motor until an edge of a next-slit-but-one of the slit disk reaches a position in the vicinity of the photosensor by supplying, to the stepping motor, drive pulses having a drive duty ratio set according to a predetermined procedure, based on the duty ratio set by the duty ratio setting means.
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16. A fluid infusion pump, having a main body and a cover securable to said main body, adapted to sandwich, between said main body and said cover, a flexible tube which is placed on a wall of said main body;
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wherein said main body is formed with a generally semi-cylindrical groove for receiving said flexible tube; said cover is formed with a recess which encloses a spring and a pressure plate which is urged by said spring toward said groove in said main body whenever said cover is closed; further comprising a plurality of fingers slidably received in a cavity formed in the wall and so aligned that respective fore end portions of said fingers sequentially engage respective axially adjacent portions of said flexible tube to compress said tube and to thereby transfer any medication fluid inside the tube longitudinally through said tube; a motor which drives said fingers via respective cams; a slit disk, mounted on a common shaft with said motor, and formed with a plurality of slits of differing circumferential length; a photosensor which detects light travelling through any of the slits of the slit disk and outputs a detection signal; a rotational position detector, coupled to an output of said photosensor, which determines rotational position of said motor, based upon said photosensor detection signal, said detector including a timer which measures a time interval between successive inversions of said detection signal and a table associating specific slits with respective time intervals; and a pressure detector located adjacent said tube, on a surface of said pressure plate within a range of area in which the fore end portions of the fingers press the tube, detecting the pressure exerted from each of the fingers via the tube, the pressure plate, and the spring, and outputting at least one detection signal representing said pressure; wherein the motor is a stepping motor, and the fluid infusion pump further comprises; reversing start duty ratio setting means, setting a stationary duty ratio by a predetermined method according to the rotational position, of the stepping motor, detected by the rotational position detecting means, and setting the duty ratio of the drive pulses at a reversing start duty ratio, at which a drive current, for making the stepping motor start to reverse in a present rotational position, is achieved by successively supplying, to the stepping motor, drive pulses having a duty ratio obtained by gradually reducing the set stationary duty ratio, until the detection signal from the photosensor is inverted in level; duty ratio setting means, setting the duty ratio of the drive pulses at a duty ratio at which a minimum drive current necessary, in a time when the stepping motor starts to be driven, is achieved by successively supplying, to the stepping motor, drive pulses having a duty ratio obtained by gradually increasing the reversing start duty ratio, set by the reversing start duty ratio setting means, until the detection signal from the photosensor is inverted in level; and motor driving means, making the stepping motor start to be driven by supplying, to the stepping motor, drive pulses having the drive duty ratio set, according to a predetermined procedure, based on the duty ratio set by the duty ratio setting means.
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Specification