CN112654378A

CN112654378A - Load detector and clamping unit

Info

Publication number: CN112654378A
Application number: CN201980058377.3A
Authority: CN
Inventors: 大冢浩司
Original assignee: JMS Co Ltd
Current assignee: JMS Co Ltd
Priority date: 2018-10-19
Filing date: 2019-10-17
Publication date: 2021-04-13
Also published as: WO2020080466A1; JP2020065557A; JP7135711B2

Abstract

Provided is a load detector capable of preventing erroneous detection of the output voltage of a load detection sensor. The load detector 66 includes a main body 61 and a lid 62 that opens and closes the main body 61, and detects a load due to pressure from a measurement target portion disposed between the main body 61 and the lid 62 when the lid 62 is closed, and includes: a load part 7 capable of moving forward and backward in the axial direction by pressure from the measurement target part; a load detection sensor 665 which is disposed opposite to the tip end of the load portion 71 and detects the load from the load portion 71; a contact portion 72 disposed in contact with the outer peripheral surface of the load portion 71 so as not to prevent the axial movement of the load portion 71; and a connection portion 73 electrically connecting the contact portion 72 and the ground portion 610.

Description

Load detector and clamping unit

Technical Field

The present invention relates to a load detector and a clamp unit for detecting a load caused by a pressure from a measurement target.

Background

Conventionally, there is known a blood purification apparatus equipped with a spinning pump including a tube through which a liquid flows, a load detection sensor for detecting a radial displacement of the tube based on a load from a load portion, and a detection portion for detecting occlusion of the tube based on a load value of the load detection sensor (see, for example, patent document 1). In the device of patent document 1, the negative pressure and the positive pressure of the tube can be detected.

Documents of the prior art

Patent document

Patent document 1 Japanese patent laid-open No. 2014-83091

Disclosure of Invention

Problems to be solved by the invention

When the radial displacement of the tube is detected by a load generated by the movement of the load portion to detect the negative pressure and the positive pressure of the tube, static electricity may be generated and charged in the load portion. When the load portion is charged with static electricity, an output voltage of the load detection sensor may be abnormal due to the influence of the static electricity, and the negative pressure and the positive pressure of the tube may be erroneously detected. Therefore, it is desirable to be able to prevent erroneous detection of the output voltage of the load detection sensor.

The invention aims to provide a load detector and a clamping unit which can prevent the output voltage of a load detection sensor from being detected by mistake.

Means for solving the problems

The present invention relates to a load detector including a main body and a lid that opens and closes the main body, the load detector detecting a load caused by a pressure from a measurement target portion disposed between the main body and the lid when the lid is closed, the load detector including: a load part capable of moving forward and backward in an axial direction by a pressure from the measurement target part; a load detection sensor disposed opposite to a tip end of the load portion and detecting a load from the load portion; a contact portion that is disposed in contact with an outer peripheral surface of the load portion so as not to interfere with movement of the load portion in the axial direction; and a connection portion electrically connecting the contact portion and a ground portion.

Preferably, the contact portion is formed in a cylindrical shape.

Preferably, the load receiving portion further includes a rotation preventing portion that prevents rotation of the load receiving portion.

The present invention relates to a clamping unit including the load detector, the measurement target portion being a tube through which a liquid flows, the clamping unit further including a clamping portion capable of clamping the tube disposed between the main body and the lid portion when the lid portion is closed.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a clamp unit capable of preventing erroneous detection of the output voltage of the load detection sensor.

Drawings

Fig. 1 is a diagram showing an overall configuration of a hemodialysis apparatus according to an embodiment of the present invention.

Fig. 2 is a front view showing the configuration of the clamping unit.

Fig. 3 is a diagram showing an open state of the clamp unit.

Fig. 4 is a perspective view showing a locked state of the clamp unit.

Fig. 5 is a perspective view of the clamp unit as viewed from the lower side.

Fig. 6 is a sectional view taken along line a-a of fig. 4.

Fig. 7 is a sectional view taken along line B-B of fig. 4.

Fig. 8 is a sectional view showing the structure of the load detection unit.

Fig. 9 is a perspective view showing a main configuration for preventing the occurrence of static electricity in the load detection portion.

Fig. 10 is an exploded perspective view of the load detection unit shown in fig. 9.

Fig. 11 is a block diagram showing the configuration of the operation unit.

Fig. 12 is a graph showing an example of output abnormality due to the influence of the output voltage and static electricity of the force sensor.

Fig. 13 is a perspective view showing the load shaft in the 1 st modification, (a) is a side view, and (b) is a view of the shaft body viewed from the tip end side.

Fig. 14 is a perspective view showing the load shaft in the 2 nd modification, (a) is a side view, and (b) is a view of the shaft body viewed from the tip end side.

Fig. 15 is a perspective view showing the load shaft and the C-shaped contact portion of the 3 rd modification, (a) is a side view, and (b) is a view of the shaft body viewed from the distal end side.

Fig. 16 is a perspective view showing the load shaft and the rod-like contact portion in the 4 th modification, (a) is a side view, and (b) is a view of the shaft body viewed from the distal end side.

Detailed Description

Hereinafter, a preferred embodiment of the hemodialysis apparatus including the holder unit 60 according to the present invention will be described with reference to the drawings. The hemodialysis apparatus according to the present invention purifies blood of a patient suffering from renal insufficiency and/or a patient suffering from drug poisoning, removes excess moisture in the blood, and supplies water (replenisher) to the blood as needed.

First, the overall configuration of the hemodialysis apparatus 1 according to the present embodiment will be described with reference to fig. 1. The hemodialysis apparatus 1 as a dialysis apparatus includes a dialyzer 10 as a hemodialyzer, a blood circuit 20, a dialysate circuit 30, a replenishment liquid line 38, and a console 100. The console 100 is provided with an operation panel 70, a holder unit 60, a part of the blood circuit 20, a part of the dialysate circuit 30, a heater 40 as a temperature adjustment unit, a drug solution pump 231, a substitution pump 39, and a control device 50.

The dialyzer 10 includes a container body 11 formed in a cylindrical shape and a dialysis membrane (not shown) housed inside the container body 11, and the inside of the container body 11 is divided into a blood-side channel and a dialysate-side channel (neither of which is shown) by the dialysis membrane. The container body 11 is formed with a blood inlet 111 and a blood outlet 112 communicating with the blood-side channel, and a dialysate inlet 113 and a dialysate outlet 114 communicating with the dialysate-side channel.

The blood circuit 20 includes an arterial line 21, a venous line 22, a drug line 23, and an overflow line 24. The arterial line 21, the venous line 22, the drug line 23, and the overflow line 24 are each mainly constituted by a flexible tube through which a liquid can flow.

In the present embodiment, the tubes constituting the arterial line 21, the venous line 22, the drug line 23, and the overflow line 24 are flexible tubes made of, for example, polyvinyl chloride (PVC), silicon (Si), or the like. As the tube, for example, a tube having an outer diameter of 5.5mm and an inner diameter of 3.3mm can be used. The hardness of the pipe may be, for example, about 50 to 85 (JIS K7215).

One end of the artery side line 21 is connected to an artery of a subject (dialysis patient), and the other end is connected to the blood inlet 111 of the dialyzer 10. A console 100 is disposed midway in the arterial line 21. In the console 100, the clamp unit 60 and the blood pump 212 are disposed in a portion through which the artery-side tube 21 passes. An artery side clamping portion (clamping portion) 65, a load detection portion 66, and an artery side bubble sensor (bubble detection portion) 67 are disposed in a portion of the clamping unit 60 through which the artery side tube 21 passes. Details of the clamp unit 60 will be described later.

The blood pump 212 is disposed downstream of the clamp unit 60 in the artery-side conduit 21. The blood pump 212 sends out a liquid such as blood and a pre-wash solution inside the artery-side tube 21 by pressing the tube constituting the artery-side tube 21 with rollers.

The vein-side line 22 has one end connected to the blood outlet port 112 of the dialyzer 10 and the other end connected to a vein of a subject (dialysis patient). The venous side chamber 222 and the console 100 are disposed in the middle of the venous side line 22. In the console 100, the clamp unit 60 is disposed in a portion through which the venous-side line 22 passes. A vein-side clamp 69 and a vein-side bubble sensor 68 are disposed in the clamp unit 60 at a portion through which the vein-side tube 22 passes. Details of the clamp unit 60 will be described later.

The venous side chamber 222 is arranged in the venous side line 22 at a position between the dialyzer 10 and the console 100. The venous side lumen 222 holds a prescribed amount (e.g., 20ml) of blood.

The drug line 23 supplies a drug necessary for hemodialysis to the artery-side line 21. One end side (proximal end side) of the drug line 23 is connected to a drug pump 231 that sends out a drug, and the other end side (distal end side) is connected to a position between the blood pump 212 and the dialyzer 10 in the artery line 21.

One end side (base end side) of the overflow line 24 is connected to the venous-side chamber 222. The overflow line 24 discharges the physiological saline, air, and the like flowing through the venous line 22 in the priming step to the outside. An overflow clamp 241 is disposed in the overflow line 24. The overflow clamp 241 opens and closes the flow path of the overflow line 24.

The blood taken out from the artery of the subject (dialysis patient) through the blood circuit 20 described above is circulated through the artery-side line 21 by the blood pump 212 and introduced into the blood-side flow path of the dialyzer 10. The blood introduced into the dialyzer 10 is purified by the dialysate flowing through a dialysate circuit 30 described later via a dialysis membrane. The blood purified in the dialyzer 10 flows through the venous-side line 22 and is returned to the subject's vein.

In the present embodiment, the dialysate circuit 30 is constituted by a dialysate circuit 30 of a so-called closed volume control system. The dialysate circuit 30 includes a dialysate chamber 31, a dialysate supply line 32, a dialysate introduction line 33, a dialysate discharge line 34, a drain line 35, a bypass line 36, and a water removal/reverse osmosis pump 37.

The dialysate chamber 31 includes a hard container 311 capable of containing a certain volume (for example, 300ml to 500ml) of dialysate, and a soft diaphragm (diaphragm)312 that partitions the inside of the container 311. The interior of the dialysate chamber 31 is divided by a diaphragm 312 into a liquid feeding accommodation portion 313 and a liquid discharge accommodation portion 314.

The proximal end of the dialysate supply line 32 is connected to a dialysate supply device (not shown), and the distal end is connected to the dialysate chamber 31. The dialysate supply line 32 supplies dialysate to the liquid supply accommodation portion 313 of the dialysate chamber 31.

The dialysate introduction line 33 connects the dialysate chamber 31 and the dialysate introduction port 113 of the dialyzer 10, and introduces the dialysate contained in the fluid feed containing portion 313 of the dialysate chamber 31 into the dialysate-side flow path of the dialyzer 10.

The dialysate extraction line 34 connects the dialysate extraction port 114 of the dialyzer 10 to the dialysate chamber 31, and extracts dialysate discharged from the dialyzer 10 to the drain holding unit 314 of the dialysate chamber 31.

The proximal end side of the drain line 35 is connected to the dialysate chamber 31, and drains the dialysate contained in the drainage container 314.

The bypass line 36 connects the dialysate extraction line 34 with the drain line 35.

A water scavenging/reverse filtering pump 37 is disposed in the bypass line 36. The water removal/reverse filtration pump 37 is configured by a pump that can be driven so as to send the dialysate in the bypass line 36 to the drain line 35 (water removal direction) and in the dialysate in the bypass line 36 to the dialysate extraction line 34 (reverse filtration direction).

The heater 40 heats the dialysate flowing through the dialysate circuit 30 to a predetermined temperature.

The replenishment liquid line 38 is a line for directly supplying dialysate to the blood circuit 20. As shown in fig. 1, the upstream side of the replenishment liquid line 38 is connected to the dialysate introduction line 33 of the dialysate circuit 30 at a position between the dialysate chamber 31 and the dialysate introduction port 113 of the dialyzer 10. The replenishment liquid line 38 is provided with a replenishment liquid clamp 381. As shown by the solid line in fig. 1, when the downstream side of the replenishment liquid line 38 is connected to a position between the blood pump 212 and the dialyzer 10 in the arterial line 21, the hemofiltration dialysis of the predilution system is performed. As shown by the broken line in fig. 1, when the downstream side of the replenishment liquid line 38 is connected to the venous side chamber 222 in the venous side line 22, the post-dilution hemodialysis is performed.

The clamping unit 60 will be explained.

As shown in fig. 1, the clamp unit 60 is formed in a unit and attached to the console 100. The holding unit 60 holds the tube constituting the arterial side channel 21 and the tube constituting the venous side channel 22 by holding them therebetween. In the grasping unit 60, the tubes constituting the arterial side channel 21 are disposed in the vertical direction on one side in the width direction H, and the tubes constituting the venous side channel 22 are disposed in the vertical direction on the other side in the width direction H.

As shown in fig. 2 to 5, the clamp unit 60 includes a unit main body 61, a lid 62 that opens and closes the unit main body 61, a hinge 63, an opening/closing lever 641, an opening/closing engagement portion 642, a substrate 664 (see fig. 5), and a load detection portion 66 (load detector). The clamp unit 60 fixes the tube by disposing the tube between the unit main body 61 and the cover 62. The clamp unit 60 fixes the tube constituting the arterial side channel 21 and the tube constituting the venous side channel 22 by pressing the inner surface of the cover 62 against the inner surface side of the unit main body 61 in a state where the tube constituting the arterial side channel 21 and the tube constituting the venous side channel 22 are arranged on the inner surface of the unit main body 61.

The inner surface of the cap 62 constitutes a tube fixing portion for fixing the tube constituting the arterial side tube 21 and the tube constituting the venous side tube 22 with a constant force. Of the members constituting the inner surface of the lid portion 62, as a material of at least a portion to press the tube, for example, a resin material, an ABS resin (acrylonitrile-butadiene-styrene copolymer), an ASA resin (obtained by polymerizing an acrylic rubber in place of the ABS resin), a synthetic resin such as polypropylene, or the like can be used. Thus, the inner surface of the cap 62 can fix the tube constituting the arterial side channel 21 and the tube constituting the venous side channel 22 with an appropriate holding force sufficient for holding without being excessively crushed.

As shown in fig. 2, the hinge 63 is disposed at the other end in the width direction H of the clamp unit 60 when the lid 62 is closed, and connects the lid 62 to the unit main body 61 so as to be rotatable.

The opening/closing lever 641 is provided at one end of the lid 62 in the width direction H when the lid 62 is closed. As shown in fig. 3, the opening/closing engagement portion 642 is provided at one end portion in the width direction H of the inner surface of the unit main body 61 so as to be engageable with the opening/closing lever 641 when the lid portion 62 is closed. The opening/closing lever 641 is operated to open and close the unit main body 61 and the cover 62.

As shown in fig. 3, a main body side artery side tube arrangement portion 611 (tube arrangement portion) and a main body side vein side tube arrangement portion 612 (tube arrangement portion) are formed on the inner surface of the unit main body 61. The main body side artery side tube disposing part 611 and the main body side vein side tube disposing part 612 are disposed on the inner surface of the unit main body 61 so as to be separated in the width direction H of the unit main body 61 and extend linearly. The main body side vein side tube arrangement portion 612 is arranged at a position closer to the hinge portion 63 side in the width direction H than the main body side artery side tube arrangement portion 611.

As shown in fig. 5, a substrate 664 is mounted on the outer surface 613 (see fig. 8) of the unit main body 61. A force sensor 665 (load detection sensor) having a load detection unit 66 (described later and shown in fig. 8) is attached to (disposed on) the 1 st surface 664a of the substrate 664 on the unit main body 61 side (shown in fig. 8).

As shown in fig. 3, a cover side artery side tube disposing part 621 disposed to face the main body side artery side tube disposing part 611 and a cover side vein side tube disposing part 622 disposed to face the main body side vein side tube disposing part 612 are formed on the inner surface of the cover 62 when the cover 62 is closed. The cover-side artery-side tube disposing part 621 and the cover-side vein-side tube disposing part 622 are disposed on the inner surface of the cover 62 so as to be spaced apart in the width direction H of the cover 62 and extend linearly. The cover-side vein-side tube placement portion 622 is disposed on the hinge portion 63 side in the width direction H with respect to the cover-side artery-side tube placement portion 621.

When the cap 62 is closed, the tube constituting the artery-side tube 21 is disposed between the main body-side artery-side tube disposing part 611 and the cap-side artery-side tube disposing part 621, and the tube constituting the vein-side tube 22 is disposed between the main body-side vein-side tube disposing part 612 and the cap-side vein-side tube disposing part 622.

First, the configuration of the main body side artery side tube arrangement portion 611 and the cover side artery side tube arrangement portion 621 will be described.

As shown in fig. 3 and 6, when the lid 62 is closed, the artery side upstream tube pressing portion 601, the artery side clamping portion 65, the load detection portion 66, the artery side bubble sensor 67, and the artery side downstream tube pressing portion 602 are arranged along the main body side artery side tube arrangement portion 611 and the lid side artery side tube arrangement portion 621. In the present embodiment, the artery-side upstream tube pressing portion 601, the artery-side clamping portion 65, the load detection portion 66, the artery-side bubble sensor 67, and the artery-side downstream tube pressing portion 602 are arranged in the clamping unit 60 in order from the upstream side toward the downstream side (from the lower side to the upper side in fig. 1 and 3).

As shown in fig. 3, the main body side artery side tube arrangement portion 611 is arranged on the inner surface of the unit main body 61. In the main body side artery side tube disposing part 611, the housing concave part 601a of the artery side upstream tube pressing part 601, the artery side movable clamping part 651 of the artery side clamping part 65, the load receiving part 662 of the load detecting part 66, the artery side bubble sensor receiving member 672 in which the ultrasonic oscillation part 671 of the artery side bubble sensor 67 is housed, and the housing concave part 602a of the artery side downstream tube pressing part 602 are disposed in line in order from the upstream side toward the downstream side (from the lower side to the upper side in fig. 3) of the liquid flowing through the tube constituting the artery side channel 21.

The cover-side artery-side tube disposing part 621 is disposed on the inner surface of the cover 62, and is disposed so as to face the main-body-side artery-side tube disposing part 611 when the cover 62 is closed. In the cap-side artery-side tube disposing part 621, the pressing convex portion 601b of the artery-side upstream tube pressing part 601, the artery-side pinching receiving part 652 of the artery-side pinching part 65, the load pressing part 663 of the load detecting part 66, the artery-side bubble sensor pressing member 674 in which the ultrasonic wave receiving part 673 of the artery-side bubble sensor 67 is housed, and the pressing convex portion 602b of the artery-side downstream tube pressing part 602 are disposed in this order from the upstream side toward the downstream side (from the lower side to the upper side in fig. 3) of the liquid flowing through the tube constituting the artery-side channel 21.

The pressing convex portion 601b of the artery-side upstream tube pressing portion 601 is disposed so as to face the accommodation concave portion 601a disposed in the unit main body 61 when the lid portion 62 is closed, and the pressing convex portion 601b presses the tube constituting the artery-side channel 21 on the upstream side (lower side in fig. 3) of the liquid flowing through the artery-side channel 21 in the grasping unit 60.

The artery side clamp receiver 652 faces the artery side movable clamp 651 disposed in the unit body 61 when the lid 62 is closed. The artery side clamp receiver 652 and the artery side movable clamp 651 constitute an artery side clamp 65, and hold the tube constituting the artery side channel 21 therebetween.

As shown in fig. 3 and 6, the artery side clamping portion 65 includes an artery side movable clamping portion 651 disposed in the unit main body 61, a solenoid 653 disposed in the unit main body 61 and driving the artery side movable clamping portion 651, and an artery side clamping receiving portion 652 disposed in the cap 62. The artery-side clamp receiver 652 is formed to protrude from the inner surface of the cap 62 and extend in the width direction H.

As shown in fig. 6, the artery-side movable clamp portion 651 is formed in a trapezoidal shape having a flat distal end extending in the width direction H and a narrow distal end side in a cross section taken in the direction in which the tube arrangement portion extends. An output shaft 653a of the solenoid 653 is connected to the rear end of the movable artery-side clamping portion 651 so as to be movable forward and backward. The movable artery-side clamping unit 651 clamps a tube constituting the artery-side conduit 21 by the tip of the movable artery-side clamping unit 651 and the tip of the movable artery-side clamping receiver 652 by advancing and retracting the output shaft 653a of the solenoid 653, or opens and closes the artery-side conduit 21.

The artery side clamping unit 65 configured as described above clamps the tube constituting the artery side conduit 21 disposed between the unit main body 61 and the cap 62 by the artery side movable clamping unit 651 and the artery side clamping receiver 652 during normal operation of the hemodialysis apparatus 1.

The artery side clamping unit 65 is opened and closed in the preflushing and blood returning steps using physiological saline. The artery side clamping unit 65 advances and retreats the artery side movable clamping unit 651, or crushes or opens the tube constituting the artery side channel 21, and opens and closes the channel of the artery side channel 21, thereby flowing/stopping the liquid feeding of the liquid flowing inside the tube at the upstream side of the artery side bubble sensor 67.

The load detection unit 66 detects a load caused by the pressure from the tube constituting the artery-side conduit 21, and can output the load as a voltage value. That is, when the tube is closed, the pressure in the tube becomes positive or negative, the radial direction of the tube changes, and the load changes at the same time, and as a result, the change in the voltage value is detected. As shown in fig. 7, the load detection portion 66 includes a load pressing portion 663, a load receiving portion 662, a force sensor 665 arranged on the substrate 664, and a load absorbing portion 80. The load detector 66 constitutes an occlusion detecting device.

As shown in fig. 3, 6, and 7, the load pressing portion 663 is disposed so as to face the load receiving portion 662 disposed in the unit body 61 when the lid 62 is closed, and presses the tube constituting the artery-side conduit 21. In addition, in order to obtain a voltage value of the same degree as the voltage value output from the load detection portion 66 when the pipe diameter is changed, the load pressing portion 663 may be configured to be adjustable in height, or may be configured to be replaceable with a load pressing portion having a different height.

The load receiving portion 662 receives a load due to a pressure from a tube (measurement target portion) constituting the artery-side conduit 21 pressed by the load pressing portion 663 when the lid 62 is closed. The load receiver 662 transmits a load to the force sensor 665 arranged on the substrate 664.

As shown in fig. 8 to 10, the load receiving portion 662 includes a surface piece portion 662a, a pressing portion 662b, a load shaft 71 (load portion), a guide tube 72 (contact portion), and a connecting member 73 (connecting portion) that connects the guide tube 72 and the ground plate 610 (ground portion). The load shaft 71, the guide tube 72, the connecting member 73, and the ground plate 610 are formed of a metal member having conductivity. The ground plate 610 is formed in a plate shape and is disposed inside the unit body 61 (see fig. 3). As shown in fig. 9, the ground plate 610 is formed in a substantially C-shape with one side opened in a plan view. The ground plate 610 constitutes a ground portion of the clamping unit 60 and is grounded (earth). For example, to the same ground as the power supply used by the clamp unit 60.

As shown in fig. 8, the surface piece portion 662a is disposed on the tube side and abuts against the tube constituting the artery-side passage 21 when the portion 62 is closed.

The pressing portion 662b, the load shaft 71, and the guide tube 72 are disposed in the communication hole 615 of the unit main body 61. The communication hole 615 is formed to communicate the inner surface of the unit main body 61 with the outer surface 613. The surface piece portion 662a, the pressing portion 662b, and the load shaft 71 are arranged in this order from the inner surface side of the unit main body 61 toward the outer surface 613 side.

The load shaft 71 is configured to: on the outer surface 613 side of the unit main body 61 in the communication hole 615 of the unit main body 61, the guide cylinder 72 can advance and retreat in the axial direction by pressure from the pipe while being guided inside the guide cylinder 72. As shown in fig. 10, the load shaft 71 includes: a shaft main body 711 formed in a rod shape extending in the axial direction; a top plate portion 712 constituting a top plate of the shaft main body 711; and a guide groove 713 (rotation preventing portion).

As shown in fig. 8, the distal end of the shaft body 711 is disposed to face the pressing surface of the force sensor 665. The force sensor 665 is pressed against the tip end of the shaft main body 711 by the shaft main body 711 advancing and retreating.

The top plate 712 is connected to the rear end of the shaft main body 711, and is formed in a disk shape protruding in the radial direction of the shaft main body 711.

The guide groove 713 extends in a groove shape in the axial direction across the outer peripheral surface of the top plate 712 and the rear end side of the shaft body 711.

The guide tube 72 is disposed in contact with the outer peripheral surface of the shaft main body 711 of the load shaft 71 so as not to hinder the axial movement of the load shaft 71. As shown in fig. 10, the guide cylinder 72 has: a cylindrical tube main body 721 extending in the axial direction of the load shaft 71; a cylindrical side flange portion 723 that protrudes radially in an annular shape from the outer circumferential surface of the cylindrical main body 721 in the middle of the axial direction of the cylindrical main body 721; and a guide protrusion 724 (rotation preventing portion).

The cylinder main body 721 is formed in a cylindrical shape surrounding the entire outer peripheral surface of the shaft main body 711. The one end portion 722 of the tube main body 721 is inserted into a coupling hole 732 of a coupling member 73 described later and coupled to the coupling member 73. The outer peripheral surface of the one end portion 722 of the cylinder main body 721 is formed by an arc surface 722a and a linear surface 722b (rotation restricting portion) which are continuous in the circumferential direction.

The shaft main body 711 is housed inside the tube main body 721 so as to be slidable in the axial direction. The inner diameter of the tube main body 721 is formed slightly larger than the outer diameter of the shaft main body 711 to such an extent that the inner diameter does not interfere with the axial movement of the load shaft 71 and the inner diameter contacts the shaft main body 711. More specifically, the shaft main body 711 is disposed so as to contact the inside of the cylinder main body 721 while moving in the axial direction, with or without contact, and in a state in which frictional resistance is hard to be applied to the shaft main body 711. Thus, the guide tube 72 is disposed in contact with the outer peripheral surface of the load shaft 71 so as not to hinder the axial movement of the load shaft 71.

The guide protrusion 724 axially protrudes from an end surface of the other end portion of the barrel main body 721 opposite to the one end portion 722. The guide protrusion 724 is disposed in the guide groove 713 of the load shaft 71. The guide protrusion 724 is disposed in the guide groove 713 of the load shaft 71, thereby preventing the load shaft 71 from rotating with respect to the guide cylinder 72. The guide cylinder 72 is fixed so that the circumferential position does not move relative to the unit main body 61. In the present embodiment, as will be described later, the guide cylinder 72 is fixed so that the circumferential position does not move relative to the unit main body 61 by fitting the linear surface 722b (rotation restricting portion) of the guide cylinder 72 into the linear surface 732b (rotation restricting portion) of the coupling member 73. Therefore, the guide groove 713 of the load shaft 71 and the guide protrusion 724 of the guide sleeve 72 constitute a rotation preventing portion that prevents the load shaft 71 from rotating with respect to the force sensor 665 fixed to the unit body 61. The guide protrusion 724 guides the movement of the guide groove 713 of the load shaft 71 when the load shaft 71 advances and retreats inside the guide cylinder 72.

Since the guide groove 713 of the load shaft 71 and the guide protrusion 724 of the guide cylinder 72 are provided, the load shaft 71 is prevented from rotating relative to the guide cylinder 72, and therefore the load shaft 71 and the force sensor 665 can be brought into contact with each other at the same position in the circumferential direction. Therefore, for example, even when the contact point is not the center of the load shaft 71 in the longitudinal direction and the length of the load shaft 71 may fluctuate depending on the contact positions in the circumferential direction, the load shaft 71 and the force sensor 665 are in contact at the same position in the circumferential direction, so that a stable load can be continuously applied and the performance can be maintained.

The coupling member 73 electrically connects the guide cylinder 72 and the ground plate 610. The connecting member 73 is formed of a plate material extending in a crank shape in a plan view, and a step portion 731 is formed in the middle of the extending in the crank shape. The coupling member 73 has a coupling hole 732 formed in one end portion and a ground connection hole 733 formed in the other end portion.

The coupling hole 732 is formed through the coupling member 73 at one end of the coupling member 73. The inner circumferential surface of the coupling hole 732 is formed by connecting an arc surface 732a and a linear surface 732b (rotation restricting portion). When the one end portion 722 of the cylinder main body 721 on the outer surface 613 side of the unit main body 61 is inserted into the coupling hole 732, the arc surface 722a and the linear surface 722b of the one end portion 722 of the cylinder main body 721 are fitted into the arc surface 732a and the linear surface 732b of the corresponding coupling hole 732. When the linear surface 722b (rotation restricting portion) of the guide cylinder 72 is fitted into the linear surface 732b (rotation restricting portion) of the coupling member 73, the rotation of the guide cylinder 72 with respect to the coupling member 73 is restricted, and the guide cylinder 72 is fixed so that the circumferential position does not move with respect to the unit main body 61. In this state, the cylinder side flange portion 723 is in contact with the upper surface of the coupling member 73, and the cylinder main body 721 is coupled to the coupling member 73 in a state where the cylinder side flange portion 723 is electrically conducted to the coupling member 73.

The other end of the coupling member 73 is connected to a ground plate 610. In the present embodiment, in a state where the ground plate 610 is placed on the upper surface of the other end portion of the coupling member 73, the ground connection hole 733 and the connection hole 610a of the ground plate 610 are connected by the screw 74, and the other end portion of the coupling member 73 is electrically connected to the ground plate 610. Thereby, the static electricity generated in the load shaft 71 escapes from the guide cylinder 72 to the ground plate 610 through the coupling member 73. The static electricity escaping to the ground plate 610 is grounded in the ground plate 610.

As shown in fig. 8, the force sensor 665 is mounted (disposed) on the 1 st surface 664a formed on the unit main body 61 side of the substrate 664. The force sensor 665 is disposed so as to face the tip end of the load shaft 71, and detects a load due to the pressure from the pipe based on the load from the load shaft 71. The substrate 664 is attached to the outer surface 613 of the unit main body 61. The substrate 664 is disposed so as to intersect the direction in which the communication holes 615 extend, and blocks the communication holes 615. The substrate 664 has a 1 st surface 664a on the unit main body 61 side abutting against the outer surface 613 of the unit main body 61, and a 2 nd surface 664b on the opposite side of the 1 st surface 664a, which is pressed toward the unit main body 61 side by 2

spring members

82, 82 described later.

The sensor 665 is arranged on the extension line of the communication hole 615 on the outer surface 613 side of the unit main body 61. The load receiving portion 662 is disposed in the communication hole 615 as described above.

When the unit main body 61 is closed by the lid 62, the tube constituting the artery-side conduit 21 and the load receiving portion 662 are disposed between the load pressing portion 663 of the lid 62 and the force sensor 665 in this order from the load pressing portion 663 side toward the force sensor 665 side.

The force sensor 665 configured as described above detects a load due to the pressure from the pipe acting on the load receiving portion 662, by the load receiving portion 662 moving in the radial direction of the pipe, via the load receiving portion 662. Thus, the force sensor 665 outputs, as a voltage, a load caused by the pressure from the tube constituting the artery-side conduit 21.

In the present embodiment, the force sensor 665 detects a load due to the pressure from the pipe from the load shaft 71, in both the case where the pipe is at a positive pressure and the case where the pipe is at a negative pressure.

As shown in fig. 8, the load absorbing portion 80 is disposed on the substrate 664. When a load equal to or greater than an allowable load (equal to or greater than a predetermined value) is applied to the force sensor 665 in a state where the unit main body 61 is closed by the lid 62 and the tube is disposed between the lid 62 and the force sensor 665, the load absorbing portion 80 absorbs the load applied to the substrate 664 via the force sensor 665. The load absorbing portion 80 includes 2 guide tabs 81 and 81 (guide members), 2 spring members 82 and 82 (biasing members), and a connecting member 83 connecting the

spring members

82 and 82.

In a normal use state of the clamp unit 60, when the cap 62 is closed, the cap 62 presses the tube constituting the artery-side conduit 21 against the force sensor 665, and the force sensor 665 detects a load due to the pressure from the tube and outputs the load as a voltage value. The detection value detected by the load detector 66 is transmitted to the controller 50, and it is determined whether or not the tube is closed. Examples of the case of tube occlusion include a case where it is forgotten to release the forceps after the connection of the blood circuit, clogging of the needle tip by thrombus at the time of blood return during treatment, sticking of the needle tip to the blood vessel wall at the time of exsanguination/dialysis, and insufficient blood flow due to the state of the blood vessel at the time of exsanguination/dialysis/blood return.

As shown in fig. 3 and 6, the artery-side air bubble sensor pressing member 674 is disposed so as to face the artery-side air bubble sensor receiving member 672 disposed in the unit main body 61 when the lid portion 62 is closed, and presses the tubes constituting the artery-side conduit 21. An ultrasonic wave receiving portion 673 is disposed inside the artery-side bubble sensor pressing member 674. An ultrasonic oscillation portion 671 is disposed inside the artery-side bubble sensor receiving member 672. The ultrasonic wave receiving portion 673 and the ultrasonic wave oscillating portion 671 constitute an artery side bubble sensor 67. The artery side bubble sensor 67 is a sensor for detecting the presence or absence of bubbles contained in the liquid flowing through the artery side channel 21. The ultrasound receiving portion 673 may be disposed inside the artery-side bubble sensor receiving member 672, and the ultrasound oscillating portion 671 may be disposed inside the artery-side bubble sensor pressing member 674.

When the cover 62 is closed, the artery-side air bubble sensor pressing member 674 (see fig. 3) presses the tube constituting the artery-side conduit 21 against the artery-side air bubble sensor receiving member 672 side. The ultrasonic wave receiving unit 673 detects the presence or absence of bubbles by detecting a difference in transmittance between liquid and bubbles by irradiating ultrasonic waves emitted from the ultrasonic wave oscillator 671 to the liquid flowing through the tube constituting the artery-side tube 21.

The pressing convex portion 602b of the artery-side downstream tube pressing portion 602 is disposed so as to face the accommodation concave portion 602a disposed in the unit main body 61 when the lid 62 is closed, and presses the tube constituting the artery-side channel 21 on the downstream side (upper side in fig. 3) of the liquid flowing through the artery-side channel 21 in the grasping unit 60.

Next, a configuration in which the main body side vein side tube arrangement portion 612 and the lid side vein side tube arrangement portion 622 are provided when the lid 62 is closed will be described.

As shown in fig. 3, when the cap 62 is closed, the vein-side upstream tube pressing portion 603, the vein-side bubble sensor 68, the vein-side clamping portion 69, and the vein-side downstream tube pressing portion 604 are arranged along the main-body-side vein-side tube arrangement portion 612 and the cap-side vein-side tube arrangement portion 622. In the present embodiment, the vein-side upstream tube pressing portion 603, the vein-side bubble sensor 68, the vein-side clamping portion 69, and the vein-side downstream tube pressing portion 604 are arranged in the clamping unit 60 in order from the upstream side to the downstream side (from the upper side to the lower side in fig. 1 and 3).

As shown in fig. 3, the main body side vein side tube arrangement portion 612 is arranged on the inner surface of the unit main body 61. In the main body side vein side tube disposing part 612, the housing recess 603a of the vein side upstream tube pressing part 603, the vein side air bubble sensor receiving member 682 of the ultrasonic oscillation part 681 housing the vein side air bubble sensor 68 therein, the vein side movable clamping part 691 of the vein side clamping part 69, and the housing recess 604a of the vein side downstream tube pressing part 604 are disposed in order from the upstream side toward the downstream side (from the upper side to the lower side in fig. 3) of the liquid flowing through the tube constituting the vein side channel 22.

The cover-side vein-side tube placement unit 622 is disposed on the inner surface of the cover 62, and is disposed so as to face the main-body-side vein-side tube placement unit 612 when the cover 62 is closed. In the cap-side vein-side tube placement portion 622, the pressing convex portion 603b of the vein-side upstream tube pressing portion 603, the vein-side air bubble sensor pressing member 684 that accommodates the ultrasound wave receiving portion 683 of the vein-side air bubble sensor 68 therein, the vein-side pinching receiving portion 692 of the vein-side pinching portion 69, and the pressing convex portion 604b of the vein-side downstream tube pressing portion 604 are arranged in order from the upstream side toward the downstream side (from the upper side to the lower side in fig. 3) of the liquid flowing through the tube constituting the vein-side tube path 22.

The pressing convex portion 603b of the vein-side upstream tube pressing portion 603 is disposed so as to face the accommodation concave portion 603a disposed in the unit main body 61 when the lid portion 62 is closed, and presses the tube constituting the vein-side tube path 22 on the upstream side (upper side in fig. 3) of the liquid flowing through the vein-side tube path 22 in the holding unit 60.

The vein-side air bubble sensor pressing member 684 is disposed so as to face the vein-side air bubble sensor receiving member 682 disposed in the unit main body 61 when the cover 62 is closed, and presses the tube constituting the vein-side tube 22. An ultrasound receiving unit 683 is disposed inside the vein-side bubble sensor pressing member 684. An ultrasonic oscillation unit 681 is disposed inside the vein-side bubble sensor receiving member 682. The ultrasonic wave receiving unit 683 and the ultrasonic wave oscillating unit 681 constitute the vein-side bubble sensor 68. The vein-side bubble sensor 68 is a sensor for detecting the presence or absence of bubbles contained in the liquid flowing through the vein-side tube 22. The ultrasound receiving unit 683 may be disposed inside the vein-side air bubble sensor receiving member 682, and the ultrasound oscillating unit 681 may be disposed inside the vein-side air bubble sensor receiving member 684.

When the cover 62 is closed, the vein-side air bubble sensor pressing member 684 (see fig. 3) presses the tube constituting the vein-side tube 22 against the vein-side air bubble sensor receiving member 682. The ultrasonic wave receiving unit 683 can irradiate the liquid flowing in the tube constituting the vein-side tube 22 with the ultrasonic wave emitted from the ultrasonic wave oscillating unit 681, detect the difference in transmittance between the liquid and the bubble, and detect the presence or absence of the bubble.

The vein-side clamp receiving portion 692 is disposed so as to face the vein-side movable clamp portion 691 disposed on the unit main body 61 when the lid portion 62 is closed. The vein-side holding receiving portion 692 and the vein-side movable holding portion 691 constitute a vein-side holding portion 69, and hold the tube constituting the vein-side conduit 22 therebetween.

As shown in fig. 3 and 7, the vein-side clamping unit 69 includes a vein-side movable clamping unit 691 disposed in the unit main body 61, a solenoid 693 disposed in the unit main body 61 and driving the vein-side movable clamping unit 691, and a vein-side clamping receiving unit 692 disposed in the lid 62. The vein-side clamp receiving portion 692 is formed to protrude from the inner surface of the lid portion 62 and extend in the width direction H.

The vein-side movable pinching portion 691 is formed in a trapezoidal shape in which the distal end is formed in a planar shape extending in the width direction H and the width of the distal end side is narrow in a cross section taken along the direction in which the tube arrangement portion extends. An output shaft 693a of the solenoid 693 is connected to the rear end of the vein-side movable holding unit 691 so as to be able to advance and retreat. The vein-side movable holding unit 691 sandwiches a tube constituting the vein-side conduit 22 by the distal end of the vein-side movable holding unit 691 and the distal end of the vein-side holding receiving unit 692 by advancing and retracting the output shaft 693a of the solenoid 693, or opens and closes the vein-side conduit 22.

The vein-side clamping unit 69 configured as described above clamps the tube constituting the vein-side conduit 22 disposed between the unit main body 61 and the lid 62 by the vein-side movable clamping unit 691 and the vein-side clamping receiving unit 692 during normal operation of the hemodialysis apparatus 1.

In addition, the vein-side pinching section 69 is controlled based on the detection result of the air bubbles by the vein-side air bubble sensor 68 or the artery-side air bubble sensor 67. When the vein-side bubble sensor 68 or the artery-side bubble sensor 67 detects bubbles more than a predetermined amount, the vein-side clamping unit 69 moves the vein-side movable clamping unit 691 in and out of the tube constituting the vein-side tube path 22, crushes the tube to close the flow path of the vein-side tube path 22, and stops the liquid supply of the liquid flowing through the inside of the tube at a position upstream of the vein-side bubble sensor 68.

The pressing convex portion 604b of the vein-side downstream tube pressing portion 604 is disposed so as to face the accommodating concave portion 604a disposed in the unit main body 61 when the lid portion 62 is closed, and presses the tube constituting the vein-side tube path 22 on the downstream side (lower side in fig. 3) of the liquid flowing through the vein-side tube path 22 in the grip unit 60.

The grasping unit 60 configured as described above can reliably grasp the tube in the grasping unit 60 by only closing the lid 62 in a state where the tube constituting the arterial-side tube 21 and the tube constituting the venous-side tube 22 are disposed in the unit main body 61.

The control device 50 is constituted by an information processing device (computer), and controls the operation of the dialysis apparatus 1 by executing a control program. The control device 50 executes control programs of various steps to control the operation of the hemodialysis apparatus 1. Specifically, the control device 50 controls the operations of the various pumps, clamps, heaters 40, and the like disposed in the blood circuit 20 and the dialysate circuit 30, and executes various steps (a priming step, a bleeding step, a dialysis step, a fluid replacement step, a blood return step, and the like) performed by the hemodialysis apparatus 1. In the hemodialysis apparatus 1 of the present embodiment, for example, the priming step, the bleeding step, the dialysis step, and the blood returning step are performed in sequence, and the time required to perform all of these steps is about 4 to 5 hours.

The priming step is a preparatory step for cleaning and cleansing the blood circuit 20 and/or the dialyzer 10.

The apheresis step is a step of filling the blood circuit 20 with blood of the patient after the puncture and performing extracorporeal circulation.

The dialysis step is performed after the apheresis step, and is a step of dialyzing and purifying blood.

The fluid infusion step is a step of rapidly infusing fluid when blood pressure is lowered during dialysis treatment.

The blood returning step is a step of returning the blood in the blood circuit 20 to the body of the patient.

Here, in the present embodiment, the control device 50 performs an operation of determining the occlusion of the tube, an operation of correcting the reference voltage (reference value) according to the elapsed time of the use of the tube, and an operation of reporting an alarm when the hardness of the tube is not suitable for the hardness of the tube used by the clamp unit 60.

To achieve the above functions, as shown in fig. 11, the control device 50 includes a control unit 51 and a storage unit 52. The control unit 51 includes a blocking determination unit 511, a correction control unit 512, and a report control unit 513.

The storage unit 52 stores in advance a reference voltage (reference value) serving as a reference for determining occlusion of the tube according to the elapsed time during which the liquid flows through the tube. The reference voltage is a reference for determining occlusion of the tube, and is an output voltage of the load detection unit 66 in a state where no pressure is applied to the inside of the tube (a state where the blood pump 212 is stopped), and is also an output voltage in a state where the tube is not occluded. The value obtained by subtracting a constant voltage from the reference voltage can be set as the threshold value of the output voltage of the load detection unit 66 when the tube has a negative pressure, and the value obtained by adding a constant voltage can be set as the threshold value of the output voltage of the load detection unit 66 when the tube has a positive pressure. Alternatively, the negative or positive voltage may be considered, and the value in the range of the absolute value of the constant voltage plus or minus may be set as the threshold value in each step (for example, the negative voltage determination threshold value Va and the positive voltage determination threshold value Vb shown in fig. 12). Thus, even when the tube becomes compliant with the liquid and/or the temperature change with the passage of time, the reference voltage stored in the storage unit 52 can be updated by the correction control unit 512 described later. The reference voltage stored in the storage unit 52 can be obtained in advance by experimental results or the like.

The storage unit 52 may store in advance a reference voltage (reference value) serving as a reference for determining occlusion of the tube according to a difference in outer dimensions of the tube, a temperature change, or the like.

The occlusion determination unit 511 determines occlusion of the tube by comparing the detection value detected by the load detection unit 66 with an occlusion threshold value set based on a reference voltage serving as a reference for determining occlusion of the tube.

The correction control unit 512 updates the correction reference voltage according to the elapsed time, based on the reference voltage stored in the storage unit 52 and serving as a reference for determining the occlusion of the tube. The correction control unit 512 performs correction at, for example, real-time timing, timing at predetermined time intervals, predetermined timing of dialysis treatment, and the like.

When the occlusion determination unit 511 determines that the tube is occluded, the notification control unit 513 reports an alarm to a notification unit such as a display screen, a display lamp, or a speaker.

When determining that the detection value detected by the load detection unit 66 at the time of closing the lid 62 is out of the preset range, the notification control unit 513 notifies a warning to a notification unit such as a display screen, a display lamp, or a speaker. Accordingly, since an alarm can be issued when the pipe is inappropriate in hardness, diameter, and wall thickness, and/or when the pipe is deformed, the pipe in an appropriate state can be used, and the detection value detected by the load detection unit 66 can be accurately obtained.

Here, the reason why the guide tube 72 is disposed in contact with the outer peripheral surface of the load shaft 71 so as not to interfere with the movement of the load shaft 71 in the axial direction in the load receiving portion 662 of the present embodiment and the guide tube 72 is connected to the ground via the connecting member 73 will be described.

Conventionally, in the clamp unit 60, the load shaft 71 is electrostatically charged by the advancing and retreating operation of the load shaft 71, and thus the output voltage of the load detection unit 66 may become an abnormal value due to the influence of the static electricity, and the force sensor 665 may erroneously detect the abnormal value.

For example, regardless of whether or not the output voltage Vs of the load detection unit 66 is an output value within the range of the negative pressure determination threshold Va, as shown in fig. 12, an output within a range lower than the negative pressure determination threshold Va may be generated due to the influence of static electricity charged in the load shaft 71, and an output abnormality due to the influence of static electricity may occur. In this case, the force sensor 665 is erroneously detected.

In addition, regardless of whether or not the output voltage Vs of the load detection unit 66 is an output value within the range of the positive pressure determination threshold Vb, as shown in fig. 12, an output higher than the range of the positive pressure determination threshold Vb may be generated due to the influence of static electricity charged in the load shaft 71, and an output abnormality due to the influence of static electricity may occur. In this case, the force sensor 665 is erroneously detected.

In contrast, in the present invention, the load receiving portion 662 is provided with a structure in which the guide tube 72 is disposed in contact with the outer peripheral surface of the load shaft 71 so as not to interfere with the axial movement of the load shaft 71, and the guide tube 72 is connected to the ground via the connecting member 73, so that static electricity generated in the load shaft 71 is discharged to the ground. This prevents the force sensor 665 from erroneously detecting due to static electricity without interfering with the movement of the load shaft 71 in the axial direction, and both the negative pressure and the positive pressure of the pipe can be accurately detected by the force sensor 665.

In particular, when 1 needle is inserted into a patient to perform dialysis by a single needle method in which both blood removal and blood return are performed continuously, the pinching operation and the pinching release operation are performed every several seconds. In the case of single-needle dialysis, since the clamping operation is performed every several seconds, static electricity is likely to occur. However, even when there is an influence of static electricity due to frequent chucking operation, according to the present invention, it is possible to appropriately prevent erroneous detection due to the influence of static electricity.

Further, the load detection unit 66 in the present invention has a precise structure so that the force sensor 665 can accurately detect both the negative pressure and the positive pressure of the pipe. Specifically, the guide tube 72 is disposed in contact with the outer peripheral surface of the load shaft 71 so as not to prevent the load shaft 71 from moving in the axial direction. The load shaft 71 accommodated in the guide tube 72 can axially retreat along the guide tube 72. The force sensor 665 facing the tip end of the load shaft 71 detects both loads due to the pressure of the pipe when the pipe is at a negative pressure and loads due to the pressure of the pipe when the pipe is at a positive pressure.

Here, for example, if a configuration is assumed in which wiring is attached to the load shaft 71 and static electricity is allowed to escape to the ground, the force sensor 665 may not be able to accurately detect both the negative pressure and the positive pressure of the pipe because resistance is applied to the load shaft 71 by the influence of the wiring attached to the load shaft 71. In contrast, according to the configuration of the present invention, the force sensor 665 can detect both negative pressure and positive pressure of the pipe with higher accuracy than a configuration in which wiring is attached to the load shaft 71 and static electricity is allowed to escape to the ground.

Further, for example, if a configuration is adopted in which a copper foil is sandwiched between the load shaft 71 and the force sensor 665 and static electricity is allowed to escape to the ground through the copper foil, the copper foil is sandwiched so as to overlap in the moving direction of the load shaft 71, and therefore the force sensor 665 may not be able to accurately detect both the negative pressure and the positive pressure of the pipe. Further, it is considered that both the negative pressure and the positive pressure of the tube cannot be detected accurately due to the change in the thickness of the copper foil due to the aged deterioration. In contrast, according to the configuration of the present invention, the force sensor 665 can detect both negative pressure and positive pressure with high accuracy, and can improve durability because of less deterioration with age as compared with a copper foil, and can maintain performance even after long-term use.

For example, in the case of a configuration in which electrostatic charging is prevented by bringing a metal brush into contact with the outer peripheral surface of the load shaft 71, there are cases in which resistance is applied to the load shaft 71 and/or the metal brush deteriorates with age due to the effect of the brush portion of the metal brush being brought into contact with the outer peripheral surface of the load shaft 71, and it is necessary to secure a space for disposing the metal brush radially outside the load shaft 71. In contrast, according to the configuration of the present invention, compared to a configuration in which a metal brush is brought into contact with the outer peripheral surface of the load shaft 71 to prevent electrostatic charging, the force sensor 665 can detect both negative pressure and positive pressure with high accuracy, and can improve durability because of less deterioration over time than a metal brush, and can be arranged in a smaller space than a case in which a metal brush is arranged radially outward of the load shaft 71, and thus the clamp unit 60 can be formed compactly.

The load detection unit 66 according to the present embodiment described above provides the following effects.

(1) The load detection unit 66 includes a unit main body 61 and a lid 62 that opens and closes the unit main body 61, and the load detection unit 66 detects a load caused by pressure from a tube disposed between the unit main body 61 and the lid 62 when the lid 62 is closed, and the load detection unit 66 includes: a load shaft 71 that can advance and retreat in the axial direction by pressure from the pipe; a force sensor 665 which is disposed opposite to the tip end of the load shaft 71 and detects the load from the load shaft; a guide tube 72 disposed in contact with the outer peripheral surface of the load shaft 71 so as not to prevent the load shaft 71 from moving in the axial direction; and a coupling member 73 for electrically connecting the guide cylinder 72 and the ground plate 610. Accordingly, the force sensor 665 can accurately detect both negative pressure and positive pressure of the pipe without interfering with the movement of the load shaft 71 in the axial direction, and can prevent erroneous detection of the force sensor 665 due to static electricity. Further, since deterioration with age is less than that in the case of using a copper foil and/or the case of using a metal brush, for example, the detection performance of the force sensor 665 can be maintained even in long-term use.

(2) The guide cylinder 72 is formed in a cylindrical shape. Therefore, the guide tube 72 is disposed so as to surround the entire circumference of the load shaft 71, and therefore the load shaft 71 is likely to contact a part of the inner circumferential surface of the guide tube 72. This enables the load shaft 71 to stably contact the guide tube 72. Thus, the force sensor 665 can be further prevented from making a false detection due to the influence of static electricity.

(3) The load shaft 71 further includes a guide groove 713 and a guide protrusion 724 that prevent rotation of the load shaft 71. This prevents the load shaft 71 from rotating, and therefore the load shaft 71 and the force sensor 665 can be brought into contact with each other at the same position in the circumferential direction. Therefore, for example, even when it is assumed that the contact point is not the center of the load shaft 71 in the longitudinal direction and the length of the load shaft 71 may fluctuate depending on the contact position in the circumferential direction, the load shaft 71 and the force sensor 665 are in contact at the same position in the circumferential direction, and a load that is stable for a long time can be maintained, and performance can be maintained.

(4) The clamp unit 60 includes a load detection portion 66, and the clamp unit 60 is configured to be able to clamp the tube disposed between the unit main body 61 and the cover portion 62 when the cover portion 62 is closed. Accordingly, even when there is an influence of static electricity due to a frequent clamping operation, for example, in the case of single-needle dialysis, it is possible to appropriately prevent erroneous detection of the force sensor 665 due to the influence of static electricity.

The preferred embodiments of the load detection unit 66 and the clamping unit 60 according to the present invention have been described above, but the present invention is not limited to the above embodiments and can be modified as appropriate.

For example, in the above embodiment, the load shaft 71 is formed in a cylindrical shape, but is not limited thereto. For example, the shaft main body 711A of the load shaft 71A may be formed in a quadrangular prism as in the 1 st modification shown in fig. 13, or the shaft main body 711B of the load shaft 71B may be formed in a triangular prism as in the 2 nd modification shown in fig. 14.

In the above embodiment, the contact portion is formed by the cylindrical guide cylinder 72, but the present invention is not limited thereto. For example, the contact portion may be formed in a C-shape that does not surround the entire circumference of the load shaft 71, as in the contact portion main body 721A of the contact portion 72A of the 3 rd modification shown in fig. 15, or may be formed in a rod-like shape, as in the contact portion 72B of the 4 th modification shown in fig. 15. When the contact portion is formed by the rod-shaped contact portion 72B, it is preferable that the contact portion 72B is formed in a linear shape extending in the axial direction of the load shaft 71 with the end portion thereof disposed in the guide groove 713, as shown in fig. 16.

The coupling member 73 is formed of a plate material extending in a crank shape in a plan view, but the shape is not limited as long as it can be grounded, and may be formed freely, such as a planar material or wiring.

In the above-described embodiment, the case where the load detection unit (load detector) is applied to the clamp unit has been described, but the present invention is not limited thereto, and may be applied to other applications. For example, the load detection unit (load detector) can be suitably used even in an environment where static electricity is generated.

Description of the reference numerals

60 clamping unit

61 Unit body (Main body)

62 cover part

66 load detector (load detector)

71 load shaft (load part)

72 guide cylinder (contact part)

73 connecting component (connecting part)

610 ground plate (grounding part)

665 force sensor (load detection sensor)

713 guide groove (rotation preventing part)

724 guide projection (rotation prevention part)

Claims

1. A load detector including a main body and a lid that opens and closes the main body, the load detector detecting a load caused by a pressure from a measurement target portion disposed between the main body and the lid when the lid is closed, wherein the load detector includes:

a load part capable of moving forward and backward in an axial direction by a pressure from the measurement target part;

a load detection sensor disposed opposite to a tip end of the load portion and detecting a load from the load portion;

a contact portion that is disposed in contact with an outer peripheral surface of the load portion so as not to interfere with movement of the load portion in the axial direction; and

and a connection section that electrically connects the contact section and a ground section.

2. The load detector of claim 1,

the contact portion is formed in a cylindrical shape.

3. The load detector according to claim 1 or 2,

the load detector further includes a rotation prevention unit that prevents rotation of the load unit.

4. A clamping unit provided with the load detector according to any one of claims 1 to 3,

the measurement target portion is a tube through which a liquid flows,

the clamping unit further includes a clamping portion capable of clamping the tube disposed between the main body and the lid portion when the lid portion is closed.