JPH01187382A - Liquid pump - Google Patents

Abstract

PURPOSE:To abate a contact friction between a finger member and a cam by relatively moving a sliding member to the finger member according to the contact friction with the driving cam, in a pump for medical applications, which compresses a tube with a lot of finger members in consecutive order transfers a liquid successively. CONSTITUTION:In a liquid pump available in a medical field for blood transfusion or the like, a compression point of a tube is successively moved by what a lot of finger members paralleled are driven in consecutive order, and thereby a liquid inside the tube is made so as to be transferred. In this case, the finger member is made up of housing a disklike driving cam 3 in a cam hole 2 of a finger member body 1 and simultaneously installing a motor shaft 5 in a shaft hole 4 installed an eccentric position of the driving cam 3. Then, a sliding member 6 is made contact with a peripheral edge of the driving cam 3, while a projection 12 of the finger member body 1 is engaged with a long hole 11 of the sliding member 6. In addition, a tension spring 14 is housed in a long groove 13 of the finger member body 1.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a liquid pump used for liquids in the medical field such as infusions and blood transfusions, and in particular to a liquid pump for sequentially moving liquids in a liquid transfer tube. This invention relates to a liquid pump with an improved so-called finger member for closing and opening a tube.

[Prior Art] Conventionally, this type of liquid pump has a plurality of finger members 22, for example, ten finger members 22, as shown in FIG. 13, arranged to face an elastic liquid transfer tube 21, as shown in FIG. 12, for example. However, these finger members 22 are each driven by driving cams 23 arranged in the same number.

These drive cams 23 are attached to the drive shaft 24 of the motor with adjacent drive cams 23 shifted by a predetermined angle (36 degrees).

That is, by rotating this drive shaft 24 with a motor, the drive cam 23 is sequentially rotated. The corresponding finger member 22 is driven. As a result, the finger member 2 is pushed by the spring 26 via the push plate 25.
The liquid transfer tube 21 biased in two directions is closed and opened. By such an operation, the liquid transfer tube 21 is sequentially pressurized from the inlet side to the outlet side, and the liquid in the liquid transfer tube 21 is transferred by moving the press closing point. Note that the finger members 22a, 22 at the lower end
b is a correction finger for preventing the occurrence of so-called pulsation in which the liquid flow rate changes.

[Problems to be Solved by the Invention] However, in the conventional liquid pump, when the liquid transfer tube 21 is made of vinyl chloride resin, a considerable force ( Approximately 6 to 8 kg) is required. For this reason,
The contact frictional resistance between the drive cam 23 and the finger member 22 also increases, for example, the drive cam 23 and the finger member 2.
When polysecure resin is used for each of 2,
Its friction coefficient is about 0.2, so the friction force is about 1.2
~1.6Kg. Here, if the distance from the center of the apogee of the drive cam 23 is 1 cm, in order to overcome the frictional force and rotate the drive cam 23, it is necessary to rotate the drive cam 23 by at least 1.2 cm.
A torque of 1.6 kg-cm is required.

Therefore, in conventional liquid pumps, the morph and power source for driving the pump have become large.

The present invention has been made in view of the above circumstances, and its purpose is to reduce the contact frictional resistance between the drive cam and the finger member, reduce the pump driving force, and downsize the pump drive motor. We are here to provide you with a liquid pump.

[Means for Solving the Problems] The present invention for solving the above conventional problems includes a drive cam and a plurality of finger members, and sequentially drives the plurality of finger members as the drive cam rotates, A liquid pump that transfers liquid by sequentially moving a pressure closing point by closing and opening a liquid transfer tube, wherein each of the finger members is disposed to face the liquid transfer tube. a finger member main body that is provided so as to be able to come into contact with the peripheral edge of the drive cam and cooperates with the rotation of the drive cam to drive the finger member, and the drive cam at a contact portion with the drive cam; a sliding member provided to be slidable relative to the finger member main body in accordance with the contact pressure of the drive cam in the rotational direction of the finger member, and the contact friction resistance between the finger member and the drive cam is reduced. The gist is that it is configured to be small.

[Operation 1] In the liquid pump of the present invention with the above configuration, the sliding member of the finger member is stopped at a predetermined position when the contact pressure with the drive cam is small; When the frictional force increases, it slides and moves in the tangential direction of the drive cam to reduce the contact frictional resistance.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows one finger member taken out of a plurality of finger members of a liquid pump according to an embodiment of the present invention. As mentioned above, a plurality of finger members are arranged facing the liquid transfer tube.
2 is a finger member main body formed in a rectangular shape, for example, from polysecure resin, and this finger member main body 1 is driven up and down along the elongated direction indicated by arrow A.

A rectangular cam hole 2 is bored in the finger member main body 1, and a disk-shaped drive cam 3, for example, is accommodated in this cam hole 2. This drive cam 3 has a shaft hole 4 at an eccentric position, and is mounted on a motor shaft 5 of a drive motor in this shaft hole 4. As in the conventional case, the drive cams of the finger members in VA contact are mounted on the motor shaft 5 at a predetermined angle, for example, in the case of 10 finger members, they are shifted by 36 degrees.

A sliding member 6 is in contact with the peripheral edge of the drive cam 3. The sliding member 6 is made of a thin stainless steel plate, for example, and is bent into a U-shaped cross section as shown in the cross-sectional structure of FIG.

This sliding member 6 is disposed so as to be movable along the lower side wall of the cam hole 2.

3 is an enlarged plan view showing the sliding member 6 taken out, FIG. 4 is a sectional view taken along line 4--4 in FIG. 3, and FIG. 5 is a side view. For example, two locking portions 7a and 7b are provided on the bent portion 6a of the sliding member 6 by cutting and raising a portion inward, and the locking portions 7a and 7b are opposed to each other. Locking portions 8a and 8b are provided on the finger member main body 1 side. Bearing housing parts 9a and 9b are formed between these locking parts 7a, 7b, 8a and 8b, and bearings 10a and 10 are placed in these bearing housing parts 9a and 9b, respectively.
b is stored. That is, bearings loa and IGb are interposed between the finger member main body 1 and the sliding member 6, so that the sliding member 6 moves in the direction shown by arrow B, that is, in the direction perpendicular to the driving direction of the finger member main body l. It is possible to slide.

The bearing storage portions 9a and 9b are provided on the surface of the sliding member 6.
A long hole 11 is provided on the opposite side along the sliding direction, and a guiding projection 12 provided on the finger member main body 1 is engaged with this long hole 11. That is, the sliding member 6 has a long hole 11.
It moves guided by the protrusion 12 in the section. The length of the elongated hole 11 is set according to at least the moving distance of the sliding member 6.

Further, a long groove 13 is provided in the finger member main body 1 corresponding to the substantially central portion of the sliding member 6, and an elastic member such as a tension spring 14 is accommodated in the long groove 13. tension spring 1
4 has one end hooked to a hook 15 provided at the tip of the sliding member 6 in the direction of movement, and the other end fixed to the finger member main body l side. As a result, the sliding member 6 is urged toward one side 1a of the finger member main body 1 by the urging force of the tension spring 14. Note that a stepped portion is provided on the peripheral edge of the finger member main body 1, and also serves as a stopper for the sliding member 6.

In a liquid pump equipped with a plurality of finger members having the above configuration, for example, 10, there is a gap between these finger members and a presser plate (not shown), for example, an inner diameter of 2.5 mm and an outer diameter of 4.0 mm.
A liquid transfer tube made of soft vinyl chloride resin is clamped. At this time, the holding plate presses the liquid transfer tube toward the finger members due to the biasing force of a spring (not shown), and the tube is always kept pressed and closed by one of the finger members. This operation is performed sequentially between adjacent finger members at different timings, and as a result, drives the relevant chave. That is, the plurality of finger members sequentially move the closing point of the tube. As a result, the liquid in the tube is transported from the suction side to the discharge side.

In such a series of operations, if we look at the operation of the negative finger members, we can see that when the contact pressure between the sliding member 6 and the drive cam 3 is small, the sliding member 6 pushes the finger member main body 1 due to the biasing force of the tension spring 14. It is urged toward the side wall 1a and stopped. When the contact pressure with the drive cam 3 increases, that is, the contact friction resistance increases, the sliding member 6 moves in the direction of arrow B against the elastic force of the tension spring 14 as the drive cam 3 rotates. Moving.

By the way, looking at the above movements of the multiple finger members,
Only one tube is always pressurizing and closing the liquid transfer tube (however, at the time of switching between pressure and closing, two tubes are momentarily closing the tube at the same time). In other words, -
Looking at just the finger members, during one rotation of the drive cam 3, the tube is compressed and closed by 1/10 rotation (36 degrees). That is, the remaining 9/lO
During the rotation, the drive cam 3 is separated from the finger member (
They may be in contact, but no force is applied)
Naturally, there is no loss of driving force due to friction. The loss of driving force occurs only during the period of 1/10 rotation for each finger member, and only during this period is the contact friction resistance between the drive cam 3 and the finger member By reducing this, the loss of driving force can be significantly reduced.

Also, whether it is a normal bearing or a linear bearing, internal rolling members (
(poles, rollers, rollers, etc.) have a structure that circulates on endless tracks provided in bearings, and the structure is complex. However, in the relationship between the drive cam 3 and the finger member, force is applied only during a period of 1/10 of one rotation. Therefore, for example, if the outer diameter of the drive cam 3 is 20 mm, the distance at which contact friction occurs between the drive cam 3 and the finger member is 1/l O of the outer circumference of the drive cam 3, which is 6.28 mm at most. Therefore, in this case,
An endless track is not necessarily required; the sliding structure of the sliding member 6 sufficiently reduces contact frictional resistance, and as a result, loss of pump driving force is significantly reduced.

In addition, in conventional liquid pumps, the amount of heat generated increases as the drive motor increases in size, and as a result, there is a risk that gas components in the liquid flowing through the liquid transfer chain will diverge, but with the liquid pump of this embodiment, this Gas emission can also be prevented.

Furthermore, in conventional liquid pumps, contact friction with the drive cam causes the finger member to oscillate, which causes the liquid transfer tube to oscillate. For this reason, the distance at which the liquid transfer channel is squeezed by the finger member changes, resulting in a situation where the amount of infusion differs, and there is a possibility that stable operation cannot be performed. On the other hand, with a single liquid pump, such lateral shaking can be prevented by reducing the contact frictional resistance and stable operation can be performed.

Although the present invention has been described above with reference to examples, the present invention is not limited to the above-mentioned examples, and can be modified in various ways without changing the gist.1 For example, the finger member body may be made of polyacetal resin. When using a material with little creep deformation, such as, the tension spring 14 can be omitted by utilizing its elasticity. That is, as shown in FIG. 6, the spring-like part 16 is integrally formed with the finger member main body 1, and the sliding member 6 is biased toward a predetermined position at the left end at the tip of the spring-like part 16. That is.

Further, as shown in FIG. 7, a part of the sliding member 6 is made into a leaf spring part 17, and the tip of the leaf spring part 17 is engaged with the side wall of the finger member main body 1, so that the elastic force of the leaf spring part 17 is utilized. Also, the above-mentioned tension spring can be omitted.

Furthermore, as a method for slidably attaching the sliding member 6 to the finger member main body l, in the embodiments shown in FIGS. The guiding protrusion 12 is provided on the sliding member 6 side, and the long groove 19 is provided on the finger member main body 1 side, as shown in FIGS. 8 to 11. Note that FIG. 8 is a front view of the finger member, and FIG. 9 is a sectional view taken along line 9-9 in FIG.
10 is an enlarged view showing the sliding member 6 taken out. The front view and FIG. 11 are also side views.

[Effects of the Invention] As described above, according to the liquid pump of the present invention, by moving the sliding member relative to the finger member main body depending on the degree of contact pressure with the drive cam, the finger member By reducing the contact friction resistance between the drive cam and the drive cam, the pump drive force can be significantly reduced, the drive motor can be downsized, and gas dissipation during liquid transfer due to heat generated by the drive motor is prevented. This has the effect that it is possible to prevent the finger members from lateral shaking and to perform stable liquid feeding.

[Brief explanation of the drawing]

Fig. 1 is a front view of a finger member according to an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along line 2-2 in Fig. 1, and Fig. 3 is an enlarged plan view showing the sliding member taken out. , FIG. 4 is a sectional view taken along line 4-4 in FIG. 3, and FIG. 5 is a side view of the sliding member.
6 to 8 are front views showing finger members according to other embodiments of the present invention, FIG. 9 is a front view taken along line 9-9 of FIG. 8, and FIG. 1O is a front view of finger members according to other embodiments of the invention. FIG. 11 is a front view showing the sliding member used in the finger member taken out; FIG. 12 is a side view of the same; FIG. 12 is a sectional view showing the structure of the liquid pump;
FIG. 3 is a front view of a conventional finger member. DESCRIPTION OF SYMBOLS 1... Main body, 2... Cam hole, 3... Drive cam, 5... Morph shaft, 6... Sliding member

Claims (2)

[Claims] (1) A drive cam and a plurality of finger members are provided, and as the drive cam rotates, the plurality of finger members are sequentially driven to close and open the liquid transfer tube and sequentially move the closure point. In the liquid pump, each of the finger members is provided so as to be able to come into contact with a finger member main body disposed facing the liquid transfer tube and a peripheral edge of the drive cam. The finger member is driven in cooperation with the rotation of the drive cam, and the finger member body is actuated in accordance with the contact pressure of the drive cam in the rotational direction of the drive cam at the contact portion with the drive cam. 1. A liquid pump comprising: a sliding member disposed to be slidable relative to the finger member, and configured to reduce contact frictional resistance between the finger member and the drive cam. (2) The finger member includes an elastic member that biases the sliding member toward a predetermined position of the main body, and the sliding member is biased by the biasing force of the elastic member when the liquid transfer tube is compressed and closed. 2. The liquid pump according to claim 1, wherein the liquid pump slides against the pressure.