JPH084623B2 - Medical liquid pump - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical liquid pump used for administering a medical liquid to a human body, and more particularly to a medical liquid pump for peristaltic movement of a plurality of fingers.

[0002]

2. Description of the Related Art As one of medical liquid pumps, a tube for transporting a liquid medicine is held between a plurality of fingers and a presser,
There is one in which a finger mechanism moves a finger by a cam mechanism to cause the chemical solution to move. The cam mechanism includes a plurality of cam plates individually associated with the fingers. The cam plates are sequentially arranged in the axial direction of the cam shaft so that the fingers sequentially press the tubes with a predetermined phase difference. But,
In this type of conventional pump, since the adjacent cam plates have the same phase difference, when the finger arranged at the most downstream in the direction of liquid flow in the tube separates from the tube (the most downstream finger is pressed (When releasing the pressure on the tube), the delivery of liquid (flow of liquid) is interrupted. This interruption causes pulsations in the liquid flow.

As one of pumps for preventing the occurrence of pulsation, a correcting finger is arranged on the further downstream side of the most downstream finger, and when the most downstream finger separates from the tube, the tube is placed downstream of the most downstream finger. On the other hand, a pump has been proposed in which the pulsation is reduced by pushing a little with a correcting finger on the side (Japanese Patent Publication No. 14432/1989). However, in this pump, the shape of the correction finger or the shape of the correction cam plate for displacing the correction finger must be a special shape different from other fingers or other cam plates. As another pump that prevents the occurrence of pulsation, a pump has been proposed in which the pressing area of the most upstream finger to the tube is made larger than that of the most downstream finger, thereby reducing the pulsation (actually developed). Sho 6
0-163938). However, also in this pump, the shape of the most upstream finger or the shape of the cam plate for displacing the most upstream finger must be a special shape different from other fingers or other cam plates.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce pulsation without using fingers and cam plates having special shapes.

[0005]

A liquid pump for medical use according to the present invention includes a plurality of circular cam plates arranged with a predetermined phase difference so that the cam mechanism displaces the fingers with a predetermined phase difference. The phase difference between the cam plate corresponding to the downstream finger and the cam plate corresponding to the second finger from the most downstream is made larger than the phase difference between at least one other adjacent cam plates. And

In use, the fingers are driven by the cam mechanism while the tubes are held between the fingers and the presser foot. This causes the fingers to perform a peristaltic movement against the retainer to push the tube sequentially and away from the tube, delivering the liquid in the tube. As the most downstream finger moves away from the tube, the volume within the tube tends to increase. This increase in volume is compensated for by the finger being pushed earlier by the finger displaced by the cam plate having a phase difference smaller than the phase difference between the cam plate at the most downstream and the second cam plate from the most downstream. As a result, pulsation is prevented. Therefore, according to the present invention, it is possible to reduce the pulsation without using a finger and a cam plate having a special shape.

The cam plate having a small phase difference can be a cam plate that is phase-shifted by 180 to 360 degrees from the cam plate corresponding to the most downstream finger. In addition, the phase difference between the cam plate corresponding to the most downstream finger and the cam plate corresponding to the second finger from the most downstream is calculated from the cam plate corresponding to the second finger from the most downstream and the most downstream. It may be larger than the phase difference from the cam plate corresponding to the third finger.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a pump 10 includes a box-shaped housing 12. The housing 12 is used so that its opening is on the front side. A box-shaped door (not shown) is openably and closably connected to the housing 12 by a hinge 14 or the like. The opening of the housing 12 is closed by the panel 16.

On the mounting surface of the panel 16, two sets of clamps 20, 22 and 24, 26 for holding the tube 18 are formed. The clamps 20 and 22 are formed on the upper side of the panel 16 and are vertically separated to hold the tube 18 substantially horizontally. On the other hand, the clamps 24 and 26 are formed on the lower portion of the panel 16 and are horizontally separated so as to hold the tube 18 almost vertically. The tubes 18 are clamps 20, 2 such that the liquid flows from above to below, that is, the upstream side is the upper side and the downstream side is the lower side.
2, the pump unit 28, the bubble sensor 30, the pressure sensor 32, and the clamps 24, 26. The tube 18 is bent on the upstream side of the clamps 20 and 22, and then is held substantially horizontally by the clamps 20 and 22.

The pump unit 28 includes a plurality of screws 34.
Is removably attached to the panel 16.
The pump unit 28 has an actuating mechanism 36 and a holding mechanism 38 for holding the tubes 18 in cooperation with each other and sending the liquid in the tubes 18, as well as a holder 40 for accommodating and holding both mechanisms 36, 38. Prepare

As shown in FIGS. 2 to 4, the holder 40 is
The first holder portion supports the actuating mechanism 36, and the second holder portion supports the holding mechanism 38. The pair of flange portions 42 are detachably attached to the front surface of the panel 16 by screws 34. The holder 40 is integrally formed of resin. The first and second holder parts are separated from each other, and the space 44 between the two holder parts is used as a space for inserting / removing the tube 18 between the actuating mechanism 36 and the pressing mechanism 38.

The actuating mechanism 36 comprises a plurality of fingers 46 housed in a holder 40 in parallel. Each finger 46
Is arranged so as to be slidable in a direction toward and away from the pressing mechanism 38 (in the illustrated example, a direction parallel to the mounting surface of the panel 16), and the pin 4 mounted on the holder 40.
8 prevents the holder 40 from being detached. The pin 48 is passed through an elongated hole 50 formed in the finger 46.

The holding mechanism 38 has a U-shaped arm 52 pivotally connected to the holder 40, a lever 54 pivotally connected to the arm 40, and a U-shaped pivotally connected to the lever. Bracket 56, an elongated retainer 58 attached to the bracket by a plurality of screws, and a stopper 60 that releasably prevents the retainer from retracting with respect to the finger 46.

As shown by the solid line in FIG. 2, when the lever 54 is pushed in parallel with the flat plate portion on the front surface of the holder 40 (in the illustrated example, parallel with the mounting surface of the panel 16), the arm 5 is moved.
2, the lever mechanism connecting the lever 54 and the bracket 56 is extended, so that the presser 58 is advanced to a position for pressing the tube 18 against the finger 46. On the other hand, when the lever 54 is pulled up as shown by the broken line in FIG.
The tube 18 is retracted to a position where the pressing of the tube 18 to the 6 is released. Therefore, the lever 58 is used to press the tube 18 against the finger 46 and the finger 4 by the lever mechanism.
The tube 18 can be selectively displaced to a position where the pressing of the tube 18 to the 6 is released. When the lever 54 is pushed in as shown by the solid line in FIG.
The connection point with and is the pivot point of the arm 52 to the holder 40,
It is displaced to a position on the side opposite to the flat plate portion with respect to the line connecting the connecting point of the lever 54 and the bracket 56. As a result, contraction of the lever mechanism is prevented, and the presser foot 58 is maintained at a position for pressing the tube 18 against the finger 46. On the other hand, when the lever 54 is raised as shown by the broken line in FIG. 2, the connection point between the arm 52 and the lever 54 is the pivot point of the arm 52 to the holder 40 and the lever 5.
4 and the connecting point of the bracket 56 are displaced toward the flat plate portion side. As a result, the lever mechanism is contracted, and the retainer 58 is displaced to a position where the pressing of the tube 18 against the finger 46 is released.

The stopper 60 is formed integrally with the lever 54, and when the lever 54 is pushed in parallel with the flat plate portion of the holder 40, the stopper 60 releasably engages with the arm 52, whereby Prevents the lever 54 from being naturally induced. The engagement of the stopper 60 with the arm 52 is released by pulling up the lever 54.

The pump unit 28 is removably attached to the panel 16 such that the moving direction of the fingers 46 is parallel to the mounting surface of the panel 16. Therefore, the holder 40 can be removed from the panel 16 and the operating mechanism 36, the pressing mechanism 38, and the holder 40 can be washed.

As shown in FIGS. 2 and 3, the fingers 4 are
The drive mechanism 62 that causes the 6 to perform a peristaltic movement with respect to the holding mechanism 38 includes a rotation source 64 that uses a motor, a cam mechanism 66 that is rotationally driven by the rotation source, and a finger 46 that controls the movement of the cam mechanism.
And a transmission mechanism 68 for transmitting the information to the panel 16
It is supported by a bracket 70 attached to the back side of the.

In the cam mechanism 66, a plurality of circular cam plates 72 individually corresponding to the fingers 46 are attached to a cam shaft 74 rotatably supported by a bracket 70 at the same pitch as the arrangement pitch of the fingers 46. . The rotation of the rotation source 64 is transmitted to the cam mechanism 66 by a timing pulley 76 attached to the output shaft of the rotation source 64, a timing pulley 78 attached to the cam shaft 74, and a timing belt 80 hung on both pulleys. .

The transmission mechanism 68 includes a plurality of push plates 82 respectively corresponding to the fingers 46 and the cam plate 72. The push plate 82 is fixed to the bracket 70 by a pin 84.
At the same pitch as the arrangement pitch of the fingers 46 and so as to be pivotally movable. Each push plate 82 has a hole 86 in which the corresponding cam plate 72 is arranged, and an engaging portion 88 that engages with the corresponding finger 46. The engaging portion 88 is
It projects forward of the panel 16 through a hole 90 in the panel 16 and also engages a corresponding finger 46 in a recess 92 formed therein. The transmission mechanism 68 includes a pin 84 for each push plate 82 as the cam plate 72 corresponding thereto rotates.
By making a pivotal movement (swinging movement) around, the finger 46 corresponding to each engaging portion 88 is reciprocated. As a result, the finger 46 makes a peristaltic movement with respect to the pressing mechanism 36.

As shown in FIG. 5, the cam mechanism has NO.
Equipped with O.13 cam plate. Each cam plate 72 has a disc portion 96, a hole 98 formed in the disc portion 96 to receive the cam shaft, and a plurality of holes 100 formed in the disc portion 96. In addition, each of the No. 2 to No. 13 cam plates has a disc portion 9
6 has a pin 102 formed therein. Holes 98 and 10
0 passes through the disc portion 36. The hole 100 and the pin 102 are formed at intervals on a virtual circle centered on the axis of the cam 98 and, by extension, the cam shaft. Cam plate 72
Pin 1 to any one hole 1 in the cam plate on the upstream side.
00, the fingers are joined with a predetermined phase difference so as to displace the fingers with a predetermined phase difference. The cam mechanism is arranged on the bracket 70 shown in FIG. 2 so that the No. 1 cam plate corresponds to the most upstream finger and the No. 13 cam plate corresponds to the most downstream finger. The phase difference between the No. 13 cam plate corresponding to the furthest downstream finger and the No. 12 cam plate corresponding to the second lowest finger is between at least one other adjacent cam plate. It is larger than the phase difference.

Referring again to FIGS. 2 and 3, the cam mechanism 66 is driven with the tube 18 held between the finger 46 and the presser 58. As a result, the finger 46 makes a peristaltic movement with respect to the presser 58 so as to sequentially push the tube 18 and move away from the tube 18, and feed the liquid in the tube 18. The tube 18 is held by at least one finger 46 and the presser 58 while the presser foot 58 is displaced to a position for pressing the tube 18 against the finger 46.

As the furthest downstream finger moves away from the tube, the volume within the tube tends to increase. This increase in volume is caused by the fingers displaced by the cam plates having a phase difference smaller than the phase difference between the NO.13 cam plate and the NO.12 cam plate to push the tube 18 earlier according to the difference between the two phase differences. This compensates and consequently prevents pulsations.

FIG. 6 shows the result of measuring the liquid delivered by the pump unit 28 with the sensor, and FIG. 7 shows the phase shift angle between the cam plates at that time. In FIG. 6, the more uniform the intervals between the meridians, the more uniform the amount of liquid delivered, that is, the smaller the pulsation. Figure 6
FIG. 7A shows the case where the phase difference between the cam plates is the same as 37 degrees as shown in FIG. In this case, the amount of liquid delivered is non-uniform and pulsation is large. Figure 6
As shown in FIG. 7B, (B) shows the phase difference between the NO.1 and NO.2 cam plates, the NO.2 and NO.3 cam plates, and the NO.3 and NO.4 cam plates. The phase difference is set to 18 degrees and the other is set to 37 degrees.
In this case, the amount of liquid delivered was almost uniform, and the pulsation was small. FIG. 6C shows the case where the phase difference between the NO.12 and NO.13 cam plates is 67 degrees and the other is 37 degrees, as shown in FIG. 7C. In this case, the amount of liquid delivered was more uniform, and there was almost no pulsation. 6 (D) and 6 (E), as shown in FIGS. 7 (D) and 7 (E), respectively, the phase difference between the cam plates of NO.12 and NO.13 is 67 degrees, and the others are shown in FIG. This is the case where the angles are shown in D) and (E). In each case, the amount of liquid delivered was more uniform and there was almost no pulsation. As is clear from FIGS. 6 and 7, the cam plates having the phase difference between the NO.12 and NO.13 cam plates are 180 to 360 from the NO.13 cam plate.
It is preferable to make the phases to be the same, and it is preferable to make the phase difference between the cam plates of NO.12 and NO.13 larger than the phase difference of other cam plates.

It should be noted that, as shown in FIG. 1, the panel 16 also receives a gutter that receives liquid flowing from a gap between the housing 12 and a door (not shown) into a space formed by the door and the panel 16. 94 may be formed on the panel 16. The gutter 94 is inclined so as to guide the received liquid to the side of the housing 12. Further, the actuating mechanism 36 and the driving mechanism 62 may have a structure that directly transmits the movement of the cam mechanism 66 to the finger 46, as shown in FIG. Furthermore, the present invention can be applied not only to the pump that moves the fingers in the direction parallel to the panel, but also to a known pump that moves the fingers in the direction orthogonal to the panel.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of a pump of the present invention and is a front view of a panel showing a state in which a pump unit is mounted.

FIG. 2 is a sectional view showing an embodiment of a pump unit and a drive mechanism.

FIG. 3 is a sectional view taken along line 3-3 in FIG.

FIG. 4 is a sectional view taken along line 4-4 in FIG.

FIG. 5 is a perspective view for explaining a combined state of the cam plates.

FIG. 6 is a diagram showing a measurement result of a flow of a liquid delivered.

FIG. 7 is a diagram showing a phase shift angle between cam plates used in the experiment.

FIG. 8 is a cross-sectional view showing another embodiment of the pump unit and the drive mechanism.

[Explanation of symbols]

 10 pump 18 tube 28 pump unit 46 finger 58 presser 66 cam mechanism 72 cam plate

Claims (3)

[Claims] 1. A medical fluid pump for peristaltic movement of a plurality of fingers to a retainer for a tube for a liquid by a cam mechanism comprising a plurality of circular cam plates individually associated with the fingers, wherein the cam mechanism comprises: A plurality of circular cam plates arranged with a predetermined phase difference for displacing the fingers with a predetermined phase difference are provided, which corresponds to the cam plate corresponding to the most downstream finger and the second finger from the most downstream. A liquid pump for medical use, wherein a phase difference between the cam plate and the adjacent cam plate is greater than a phase difference between at least one other adjacent cam plates. 2. The pump according to claim 1, wherein the cam plate having a small phase difference is phase-shifted by 180 to 360 degrees from the cam plate corresponding to the most downstream finger. 3. The phase difference between the cam plate corresponding to the most downstream finger and the cam plate corresponding to the second most downstream finger is the same as the cam plate corresponding to the second most downstream finger. The pump according to claim 1, which has a phase difference larger than that of a cam plate corresponding to the third finger from the most downstream.