Infusion pump

Abstract

To provide an infusion pump capable of preventing free flow regardless of whether a door is open or closed.SOLUTION: An infusion pump includes an infusion pump body 2 having a pump part 10, a door 4 disposed so as to be freely opened and closed relative to the infusion pump body 2, and a tube clamp mechanism 5 for occluding an infusion tube 100 with the door 4 open, and releasing the occlusion of the infusion tube 100 with the door 4 closed. The tube clamp mechanism 5 includes a release protrusion 42 disposed on an inner surface of the door 4 and having an inclined surface at a tip, and a clamp member 52 disposed on the infusion pump body 2, having a curved surface 524 on a tip surface, in a state where the inclined surface of the release protrusion 42 is not pressing the curved surface 524, closing against the receiving member 514 to occlude the infusion tube 100, and in a state where the inclined surface of the release protrusion 42 is pressing the curved surface 524, opening against the receiving member 514 to release the infusion tube 100.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a medical infusion pump. [Background technology]

[0002] In medical settings, infusion pumps are used to deliver medicinal fluid from an infusion tube. The infusion pump holds an infusion tube connected to a medicinal fluid bag, and is equipped with a pump mechanism that delivers the fluid by pressing the outer circumferential surface of the infusion tube with multiple fingers (see Patent Document 1).

[0003] The infusion pump holds the infusion tube between the main body and the door, and sandwiches the infusion tube between the fingers of the pump mechanism and a backplate attached to the back of the door. The infusion is delivered by sequentially operating each finger in a peristaltic motion.

[0004] In such a conventional infusion pump, when the pump operation is stopped and the door is closed, one of the fingers presses the infusion tube, so the liquid in the infusion tube does not flow freely. On the other hand, when the door is opened, the pressure on the infusion tube by the fingers is released, and there is a risk of the liquid in the infusion tube flowing freely to the patient (free flow).

[0005] For this reason, in this type of infusion pump, a clip or the like is used to prevent free flow, as described in Patent Document 1.

[0006] The advantage of using the above clip is that it can be attached to the infusion pump in advance, but the problem is that the structure of the free-flow prevention mechanism becomes complicated because the clip is removable. Also, if a clamp or the like is installed, the clip is not necessary.

[0007] For this reason, a free-flow prevention mechanism has been devised that directly blocks the infusion tube without using a clip, as shown in FIG.

[0008] The tube clamp (500), which is the free-flow prevention mechanism in the illustrated example, has a clamp lever (520) that is provided on the infusion pump body (2) side and performs opening and closing operations, a receiving member (514) that cooperates with the clamp lever (520) to clamp the tube, and a pressure spring member (550) that biases the clamp lever (520) toward the receiving member (514).

[0009] In the illustrated example, the door (4) is in a closed state, and the inclined tip surface (523A) of the clamp lever (520) is pressed by the inclined tip surface of the release projection (42) provided on the inside of the door (4), causing the clamp lever (520) to move leftward in the figure about the pivot shaft (601) against the force of the pressing spring member (550), and the gap between the clamp lever (520) and the receiving member (514) is opened. The infusion tube (100) is disposed between the clamp lever (520) and the receiving member (514).

[0010] On the other hand, when the door (4) is opened, the pressing force of the release projection (42) is released, and the clamp lever (520) moves toward the receiving member (514) by the biasing force of the pressing spring member (550) to the closed state, and the infusion tube 100 located therebetween is blocked, thereby preventing free flow. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] JP 2017-153561 A Summary of the Invention [Problem to be solved by the invention]

[0012] However, in the illustrated example, the free-flow prevention mechanism does not completely match the open / closed state of the door with the blocked state of the infusion tube, and so when the door is opened by mistake, there is a risk that the free-flow phenomenon will occur at a specific time when the door is opened or closed, for example, if the door is opened by mistake, the timing at which the clamp lever activates to block the infusion tube may be delayed, or if the door is completely closed and the peristaltic pump fingers block the infusion tube, the clamp lever may open.

[0013] An object of the present invention is to provide an infusion pump that can prevent free flow regardless of whether the door is open or closed. [Means for solving the problem]

[0014] (1) The medical pump of the present invention is a medical pump that delivers a liquid through an infusion tube, an infusion pump body having a pump portion; a door disposed so as to be freely opened and closed relative to the infusion pump body; a tube clamp mechanism that closes the infusion tube when the door is open and releases the blockage of the infusion tube when the door is closed, The tube clamp mechanism includes: A release protrusion disposed on an inner surface of the door and having an inclined surface at a tip thereof; and a clamp member that is disposed on the infusion pump body and has a curved portion on its tip surface, and closes against a receiving member to block the infusion tube when the inclined surface of the release protrusion is not pressing against the curved portion, and opens against the receiving member to release the infusion tube when the inclined surface of the release protrusion is pressing against the curved portion (hereinafter referred to as the "first medical pump of the present invention").

[0015] According to the first medical pump of the present invention, since the tip surface of the clamp member has a curved surface, the opening degree of the clamp member when pressed against the inclined surface of the release protrusion, that is, the ratio of the opening angle, can be reduced (smaller), and the clamp member can be prevented from opening more than necessary. Therefore, when the door is opened by mistake, the clamp member can be quickly closed, and free flow can be prevented.

[0016] Furthermore, when the door is closed, the opening operation of the clamp member proceeds little by little, so that the infusion tube is first blocked by the fingers, thereby preventing free flow.

[0017] (2) In the medical pump of the present invention, the clamp member has a slope portion formed continuously with the curved surface portion on the tip surface, The opening degree of the clamping member is maximized when the tip surface that contacts the inclined surface of the release protrusion switches from the curved portion to the inclined portion (hereinafter referred to as the "medical pump of the second invention").

[0018] According to the medical pump of the second aspect of the present invention, the tip surface of the clamping member is formed with a sloped surface that is continuous with the curved surface, so that the opening degree of the clamping member can be easily set. That is, when the sloped surface of the release protrusion contacts and presses the tip surface, the curved surface initiates the opening operation of the clamping member, and the sloped surface ends the opening operation, so that the degree to which the clamping member opens can be adjusted by adjusting the position of the sloped surface. This makes it possible to prevent the clamping member from opening more than necessary, to quickly close the clamping member, and to prevent free flow. Effect of the Invention

[0019] According to the present invention, it is possible to provide an infusion pump that can synchronize the opening and closing state of a door with the operation of a free-flow prevention mechanism. [Brief description of the drawings]

[0020] [Figure 1]FIG. 1 is a perspective view showing the overall configuration of an infusion pump. [Diagram 2] FIG. 2 is a perspective view showing the overall configuration of the tube clamp. [Diagram 3] 1 is a plan view showing the internal structure of a tube clamp as viewed from below. FIG. [Figure 4] FIG. 4 is a perspective view showing a configuration of a clamp lever. [Diagram 5] FIG. 4 is a perspective view showing a configuration of a latch lever. [Figure 6] FIG. 4 is a perspective view showing a configuration of a release lever. [Figure 7] 13 is a plan view showing a state in which the inclined surface of the release protrusion on the door side first comes into contact with the curved portion of the tip surface of the clamp lever. FIG. [Figure 8] 13 is a plan view showing a state in which the inclined surface of the release protrusion abuts on the inclined portion of the tip surface of the clamp lever when the door is completely closed. FIG. [Figure 9] FIG. 4 is an exploded perspective view showing the configuration of an obstruction detection mechanism. [Figure 10] FIG. 4 is a cross-sectional view showing the structure of an obstruction detection mechanism. [Figure 11] 1 is a cross-sectional view showing the drip-proof structure of the door and the infusion pump body. [Figure 12] 1 is a cross-sectional view showing the structure around the door and the packing member of the infusion pump body. FIG. [Figure 13] FIG. [Figure 14] FIG. [Figure 15] FIG. 1 is a perspective view of a packing member viewed from below; [Figure 16] 1 is a perspective view showing a peripheral structure of a pump section opening of a main frame as viewed from the back side. FIG. [Figure 17] 1 is a schematic diagram showing the relationship between the fingers, infusion tube, and back panel of a peristaltic pump in a configuration having a barrier protrusion. FIG. [Figure 18] 1 is a schematic diagram showing the relationship between the fingers, infusion tube, and back panel of a peristaltic pump in a configuration without a barrier protrusion. FIG. [Figure 19]FIG. 2 is a perspective view showing a schematic configuration of a door handle. [Figure 20] FIG. 4 is a schematic diagram showing the positional relationship between a door handle and a lock pin. [Figure 21] FIG. 1A is a plan view showing the overall configuration of the door handle of the present embodiment, and FIG. 1B is a plan view showing the overall configuration of a conventional door handle. [Figure 22] FIG. 1 is a plan view showing the internal structure of a conventional tube clamp as viewed from below. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The infusion pump 1 of the present invention comprises an infusion pump body 2 and a door 4, as shown in Fig. 1. Fig. 1 is a perspective view showing the overall configuration of the infusion pump 1, with the door 4 open. The surface of the door 4 is provided with various operation switches and a display for displaying the status of the infusion pump 1, but a description thereof will be omitted in this specification.

[0022] The door base 47 of the door 4 (corresponding to the inner surface of the door in this invention) is formed with a bearing portion 49 having a bearing hole therethrough for fixing the door 4 to the infusion pump main body 2 so that it can be opened and closed freely, and a pair of hinge members 301 fixed to the infusion pump main body 2 are arranged above and below it.

[0023] The hinge member 301 has bearing holes formed therein, which are aligned with the bearing holes of the bearing portion 49. A thin, rod-like rotating shaft 303 is inserted into the bearing holes with its head facing downward, and its upper end is fixed by a shaft fixing member 304, thereby fixing the door 4 to the infusion pump body 2 so as to be freely rotatable.

[0024] A tube mounting groove 31 is formed in the infusion pump body 2 at a position that penetrates to the upper limit, approximately in the center of the main frame 3 excluding various structures, and the infusion tube 100 is attached to this portion by penetrating the front of the infusion pump body 2 from top to bottom.

[0025] A first occlusion detection mechanism 6A is arranged above along the tube mounting groove 31 of the main frame 3, and further below that a peristaltic pump 10 (corresponding to the pump section of the present invention) equipped with multiple fingers 10n is exposed through the pump section opening 8.

[0026] When the infusion tube 100 is attached to the tube attachment groove 31 so as to penetrate vertically and the door 4 is closed, the back plate 45 presses the infusion tube 100 toward the peristaltic pump 10. When the peristaltic pump 10 is operated in this state, the multiple fingers 10n move up and down in sequence like a peristaltic motion, and the liquid in the infusion tube 100 can be discharged.

[0027] Further, an air bubble sensor 11 for detecting air bubbles is disposed below the peristaltic pump 10, below which a second clogging detection mechanism 6B is disposed, and below which a tube clamp 5 (corresponding to the tube clamp mechanism of the present invention) which is a free-flow prevention mechanism is disposed. In the following explanation, when describing the contents common to the first clogging detection mechanism 6A and the second clogging detection mechanism 6B, the suffixes A and B at the end of the reference numerals will be omitted, and the mechanism will be simply referred to as the clogging detection mechanism 6.

[0028] In addition, a handle 21 for carrying the infusion pump 1 is formed on the upper part of the infusion pump body 2 for holding the infusion pump 1 when moving it, and feet 22 are formed on each of the four corners of the lower part for stably fixing the infusion pump body 2.

[0029] On the door 4 side, occlusion sensor holding members 43A, 43B are arranged on a back panel 41 formed on a door base 47 at positions corresponding to the occlusion detection mechanisms 6A, 6B, a back plate 45 is arranged at a position corresponding to the peristaltic pump 10, and an air bubble sensor holding member 46 is arranged at a position corresponding to the air bubble sensor 11.

[0030] Furthermore, a tube clamp 5, which is a free-flow prevention mechanism, is disposed below the air bubble sensor pressing member 46.

[0031] [Tube clamp 5 configuration] The following provides a detailed description of the configuration of the tube clamp 5. As shown in Fig. 2, the tube clamp 5 has a clamp lever 52 (corresponding to a clamp member of the present invention) attached to a housing 51, a latch lever 53, and a release lever 54.

[0032] The tip of the clamp lever 52 is positioned within a first opening 515 in the front wall 512 of the housing 51, and is capable of moving freely toward (hereinafter referred to as closing) or away from (hereinafter referred to as opening) a receiving member 514 formed in the housing 51 like scissors.

[0033] The receiving member 514 is a rectangular prism-shaped structure formed between the first opening 515 and the second opening 516 of the housing 51 and having a tapered cross section. One end face of the receiving member 514 faces the clamp lever 52 and has a function of clamping the infusion tube 100 together with an edge portion 522 of the clamp lever 52. The length of the edge portion 522 of the ramp lever 52 is equal to or slightly shorter than the length of the receiving member 514.

[0034] The housing 51 has upper and lower notches 517 formed corresponding to the portion where the clamp lever 52 opens and closes, and the infusion tube 100 (not shown) is arranged to penetrate vertically inside this notch 517. Therefore, the infusion tube 100 arranged inside the notch 517 is arranged between the clamp lever 52 and one end surface of the receiving member 514.

[0035] An edge portion 522 is formed on the clamp lever 52 at a portion facing the receiving member 514. The edge portion 522 is tapered to have a triangular cross section just like a knife edge, so that it can effectively crush and close the infusion tube 100. However, the tip edge is rounded so as not to damage the infusion tube 100.

[0036] The latch lever 53 has the function of forcibly opening the clamp lever 52 when the door 4 is in the open / closed state. The latch lever 53 is disposed in the second opening 516 of the front wall 512 on the right side of the clamp lever 52 so as to be in line with it, and protrudes from the second opening 516 before operation. When in operation, it can be operated by pushing it inward.

[0037] The release lever 54 has the function of closing the clamp lever 52 that has been placed in an open state by the operation of the latch lever 53. The release lever 54 is disposed in parallel below the clamp lever 52 (top and bottom in FIG. 1), and when the latch lever 53 is pushed in to open the clamp lever 52, the tip of the release lever 54 protrudes from the first opening 515. When releasing the open state of the clamp lever 52, the clamp lever 52 can be closed by pushing this tip portion inward.

[0038] 3 is a plan view showing the internal structure of the tube clamp 5 as viewed from below. For ease of understanding, some of the structures are shown in transparent form or omitted.

[0039] In the figure, a spring fixing block 551 is fixed to the base 511 of the housing 51, and one end of a pressure spring member 550 is disposed in a spring housing hole formed on the left side surface of the spring fixing block 551. The other end of the pressure spring member 550 is disposed in a pair of pressure spring mounting recesses 527 formed in the clamp lever 52.

[0040] 4, the clamp lever 52 is a horizontally long rectangular plate-like body with a clamp shaft hole 521 formed at one end for fixing to the clamp rotation shaft 601 and an edge portion 522 formed at the upper edge of the other end. The length of the edge portion 522 may be any length that allows the infusion tube 100 placed against the edge portion 522 to be crushed even if it is slightly displaced in the longitudinal direction.

[0041] Also, a flat portion 525a is formed as an edge that extends linearly from the edge portion 522 toward one end 529 (the left end in FIG. 4), an arc-shaped recess 525b that is recessed inwardly and convexly is formed from the end of this flat portion 525a, and further an inclined portion 525c is formed that extends linearly and inclined upward from the end of the arc-shaped recess 525b toward the one end. Therefore, the one end 529 side is wider (the length in the vertical direction in FIG. 4) than the other end side.

[0042] In the clamp lever 52, the height of the tip edge of the edge portion 522 (the length in the vertical direction in FIG. 4) is approximately equal to the height of the clamp shaft hole 521. A pair of pressure spring mounting recesses 527 and a protrusion 528 are formed approximately in the center of the underside 526 of the clamp lever 52. Chamfered portions 528a are formed on both ends of the protrusion 528 to make it easy to attach the pressure spring member 550.

[0043] On the other end side of the clamp lever 52, a sloped portion 523 is formed from the edge portion 522 toward the tip (other end side). The sloped portion 523 is formed in a linear shape and inclined so that the length of the clamp lever 52 on the edge side of the edge portion 522 is short and the length on the widthwise center side is long. The sloped portion 523 is formed up to the widthwise center position on the edge portion 522 side of the clamp lever 52.

[0044] The end face of the inclined surface portion 523 is inclined. The inclination angle of the inclined surface portion 523 depends on the shape of the release protrusion 42 on the door 4 side, but is, for example, about 25 to 35°, preferably about 27 to 31° with respect to an imaginary line perpendicular to a straight line extending from the end edge of the edge portion 522.

[0045] In this embodiment, the inclined surface portion 523 is set so as not to press the clamp lever 52 even when it comes into contact with the inclined surface of the release protrusion 42. Therefore, by adjusting the formation position of the inclined surface portion 523, the opening degree of the clamp lever 52 can be adjusted.

[0046] A curved surface portion 524 is formed on the edge of the inclined surface portion 523, that is, from the center position in the width direction on the other end side of the clamp lever 52 to the lower edge (the lower end in FIG. 4) of the clamp lever 52. The curved surface portion 524 is formed as an arc with a constant curvature.

[0047] The curvature of curved surface portion 524 is not particularly restricted, but when expressed as an arc of radius R, where R1 is the length from the center of clamp shaft hole 521 to the farthest end of the tip, R is approximately 1 / 7R1 to 1 / 15R1, and preferably 1 / 8R1 to 1 / 12R1.

[0048] An end face of the curved portion 524 forms a curved surface. The curved surface of the curved portion 524 and the inclined surface of the inclined portion 523 cooperate with the release protrusion 42 on the door 4 side to open and close the clamp lever 52. When the door 4 is opened or closed, mainly the curved surface of the curved portion 524 comes into contact with the release protrusion 42 on the door 4 side.

[0049] That is, when the door 4 is being closed, first the inclined surface of the release protrusion 42 comes into contact with the curved surface portion 524. Thereafter, as the closing operation of the door 4 progresses, the contact point of the inclined surface of the release protrusion 42 moves from the curved surface portion 524 to the inclined surface portion 523 just before the door 4 is completely closed, and the clamp lever 52 will no longer open any further.

[0050] When the door 4 is opened, the opposite occurs; however, when the contact point of the inclined surface of the release protrusion 42 moves to the curved portion 524, the clamp lever 52 closes rapidly, and the infusion tube 100 is quickly blocked.

[0051] In FIG. 3, a crank-shaped clamp fixing plate 552 is fixed to a spring fixing block 551 , and a clamp rotating shaft 601 fixed to the clamp fixing plate 552 supports the clamp lever 52 .

[0052] A latch lever 53 is disposed on the right side of the clamp lever 52, and a latch rotation shaft 603 implanted in the base 511 of the housing 51 is inserted into and pivoted through a latch shaft hole 532 (see FIG. 5).

[0053] As shown in FIG. 5, the latch lever 53 has a main body 531, a latch shaft hole 532 formed on the tip side of the main body 531 (right side in FIG. 5), an arm portion 533 formed toward the upper side of the latch shaft hole 532, and an operating portion 533a formed on the tip side of the arm portion 533.

[0054] A cutout 534 cut into a U-shaped cross section and mounting parts 531b formed on both sides of the cutout are formed behind the latch lever 53. A bearing 537 having a surface covered with a covering member 537a is disposed inside the cutout 534 and is journaled by a roller shaft 538 fixed to a roller shaft hole 535 of the mounting part 531b.

[0055] Further, a release engagement protrusion 536 is formed on one side of the main body 531, which is adapted to be able to engage with the end of the release lever 54. A recess 531a is formed in the center of the main body 531.

[0056] In FIG. 3, the bearing 537 of the latch lever 53 abuts against the edge of the clamp lever 52 .

[0057] The release lever 54 is disposed in front of the latch lever 53, and is supported by a latch rotation shaft 603 inserted through the release shaft hole 542. In other words, the latch lever 53 and the release lever 54 are supported by a common shaft.

[0058] As shown in FIG. 6, the release lever 54 is formed from a substantially L-shaped plate member and has a lever base 541 and a lever arm 544 extending upward from one end thereof, and the upper end of the lever arm 544 is formed by bending it outward (toward the viewer in the figure) to form a lever operating portion 544a having a flat surface on the upper portion.

[0059] Furthermore, a release spring fixing hole 545 is formed in the lower part of the lever arm 544. A release shaft hole 542 is formed in the other end side of the lever base 541, and a latch locking arm 543 is formed near one end side of this release shaft hole 542. A latch locking projection 543a is formed at the tip of this latch locking arm 543 by bending the latch locking arm 543 inward (toward the back of the drawing).

[0060] As clearly shown in Figure 3, when the operating portion 533a of the latch lever 53 is pressed and the latch lever 53 rotates, the bearing 537 of the latch lever 53 slides over the inclined portion 525c and the arc-shaped recess 525b (see Figure 4), which are the edge side edge of the clamp lever 52, pressing and moving the latch lever 53 to the left, operating the clamp lever 52 to open it around the clamp rotation axis 601.

[0061] At this time, when the sliding bearing 537 moves from the arc-shaped recess 525b of the clamp lever 52 further to the flat portion 525a, the axis center of the roller shaft 538 of the bearing 537 becomes positioned above the axis center of the latch rotation shaft 603. As a result, the latch lever 53 cannot be returned to its original position by the pressing force to the right applied by the clamp lever 52, and is fixed in that position, so that the clamp lever 52 is maintained in the open state.

[0062] Furthermore, at this time, when the lower edge of the release lever 54 abuts against the release engagement projection 536 of the latch lever 53, the release lever 54 also rotates together with the latch lever 53 against the biasing force of the release spring member 556. As a result, the lever operating portion 544a of the release lever 54 protrudes from the first opening 515.

[0063] On the other hand, when releasing and closing the clamp lever 52 opened by the latch lever 53, first, the lever operating portion 544a of the released lever 54 that has been pushed up is pushed down to rotate the released lever 54 in the opposite direction. At this time, when the latch engagement projection 543a abuts against the upper edge of the lever base portion 531 of the latch lever 53, the latch lever 53 also rotates together.

[0064] [Tube clamp 5 operation] Next, the operation of the tube clamp 5 will be described. First, as shown in Fig. 7, when the door 4 is closed, the tip surface of the release protrusion 42 of the door 4 comes into contact with the curved surface portion 524 of the clamp lever 52. Note that, although the clamp lever 52 is open by the thickness of the crushed infusion tube 100 in Fig. 7, it is shown in a completely closed state for ease of understanding.

[0065] The tip surface of the release projection 42 is inclined relative to the clamp lever 52 so that the edge portion 522 side is higher and the curved surface portion 524 side is lower. The inclination angle of the tip surface of the release projection 42 is equal to or slightly smaller than the inclination angle of the inclined surface portion 523 of the clamp lever 52 with respect to a virtual line perpendicular to a vertical line approximating the axial center of the infusion tube 100 that is attached by penetrating vertically. More specifically, it is about 24 to 34°, and preferably about 26 to 30°.

[0066] Next, when door 4 is further closed from the state shown in FIG. 7, curved portion 524 of clamp lever 52 is pressed against the inclined tip surface of release protrusion 42, and clamp lever 52 is pushed to the left and rotates around clamp rotation shaft 601, opening relative to clamp receiver 514.

[0067] At this time, the inclined tip surface of the release protrusion 42 presses the curved portion 524, so that the movement length or pushing length during the opening and closing operation of the door 4, i.e., the opening degree of the clamp lever 52 corresponding to the movement length or pushing length of the release protrusion 42, i.e., the ratio of the opening angle, can be reduced, thereby preventing excessive opening.

[0068] Next, as shown in FIG. 8, just before the door 4 is completely closed, the inclined tip surface of the release protrusion 42 abuts against the curved portion 524 and the inclined portion 523 of the tip surface of the clamp lever 52. When the release protrusion 42 abuts against the inclined portion 523, the tip surface of the clamp lever 52 can no longer be pressed any further, and the opening operation of the clamp lever 52 stops.

[0069] In other words, the opening degree of the clamp lever 52 is maximum when the tip surface of the clamp lever 52 that contacts the inclined surface of the release protrusion 42 switches from the curved surface portion 524 to the inclined surface portion 523. The position of the clamp lever 52 at this opening degree is a position where the clamp lever 52 can release the compression of the infusion tube 100 to ensure fluidity, and is not too open relative to the infusion tube 100.

[0070] When the door 4 is opened, the clamp lever 52 is closed by performing the above-mentioned operations in reverse, and the infusion tube 100 is blocked. At this time, the clamp lever 52 is properly adjusted so that it is not opened too much, and can be quickly closed.

[0071] [Configuration of blockage detection mechanism 6] Next, we will explain the configuration of the occlusion detection mechanism 6. In this embodiment, the occlusion detection mechanism 6 has an upper occlusion detection mechanism 6A and a lower occlusion detection mechanism 6B, but because both have the same configuration, for convenience, these will be collectively referred to as the occlusion detection mechanism 6 below.

[0072] As shown in Fig. 9, the occlusion detection mechanism 6 includes a sensor case 61, a waterproof cap 62, a shaft guide 63, a shaft 64, a sensor board 65, and a cap 66. Fig. 9 is an exploded perspective view showing the occlusion detection mechanism 6 in an exploded state as viewed from the rear.

[0073] The sensor case 61 protects the entire occlusion detection mechanism 6, and has at its tip end a pair of protrusions 613 and a detection recess 614 formed therebetween. At the center, a detection hole 612 is formed that penetrates from the rear to the tip.

[0074] A circuit board storage section recessed from the rear end face is formed on both sides of the detection hole 612 at the rear of the sensor case 61, and a fixing recess 617 similarly recessed from the rear end face is formed on both sides of the circuit board storage section. A screw insertion hole 616 for fixing is formed in the center of the fixing recess 617.

[0075] 10, a screw attachment portion 618 is formed on the back surface side of fixing recess 617, which is recessed from side surface portion 611. Note that FIG.

[0076] The waterproof cap 62 is a cylindrical member with a closed tip surface 621, and a flange portion 623 is formed on the base end side of the cylindrical body portion 622 to ensure close contact with the inner surface of the detection hole 612. The waterproof cap 62 is made of a flexible and elastic material such as silicone resin, synthetic rubber, or natural rubber.

[0077] The shaft guide 63 is a tapered cylindrical member, and has a shaft guide hole 631 formed therein for accommodating the shaft 64 .

[0078] The outer shape of the shaft guide 63 is formed from the base end side with a large diameter portion 633 having a base end surface 632, a medium diameter portion 634 whose diameter is reduced via a step portion, and a small diameter portion 635 whose diameter is further reduced via a step portion, and a tip surface 636 is formed at the tip of this small diameter portion 635.

[0079] The shaft guide 63 is a member that regulates the position of the shaft 64 housed inside and ensures slidability, and is preferably made of a resin with low friction resistance. For example, general resins such as polyvinyl chloride (PVC) and ABS may be used, or polyacetal / polyoxymethylene resins with good lubricity may be used.

[0080] The shaft 64 is a cylindrical member and has a function of transmitting the pressure of the infusion tube 100 to the pressure detection element 653. The shaft 64 has a body portion 641 of a constant outer diameter, and a base end surface 642 and a tip end surface 643 perpendicular to the body portion 641.

[0081] The material constituting the shaft 64 is preferably a metal, which is a hard material that is resistant to deformation, since the pressure of the infusion tube 100 needs to be reliably transmitted to the pressure detection element 653, and among metals, stainless steel is preferable, which is rust-resistant, easy to process, and relatively inexpensive. For example, common stainless steels such as SUS303, SUS304, and SUS316 may be used, and harder stainless steels such as SUS410, SUS403, and SUS440C are preferable.

[0082] The sensor board 65 has a function of mounting and holding the pressure detection element 653 and connecting to other electronic circuits. The sensor board 65 has a circuit board 651, the pressure detection element 653, and a connection element 652.

[0083] The cap 66 closes the rear end of the sensor case 61 and has the function of holding the waterproof cap 62, shaft guide 63, shaft 64, and sensor board 65 inside the sensor case 61. The cap 66 has a rectangular body 661 that matches the external shape of the sensor case 61, and is provided with a screw window 665 for accessing the fixing recess 617 of the sensor case 61 and a connection window 664 for accessing the connection element 652 of the sensor board 65.

[0084] Cap 66 has plate-shaped arms 662 protruding upward on both sides and jaws 663 formed at the tips of arms 662, and as shown in Figure 10, jaws 663 engage with the edge of screw mounting portion 618 of cap 66 to form a snap fit.

[0085] 10, a shaft 64 is disposed inside a shaft guide 63, and the tip portion of the shaft guide 63 is covered with a waterproof cap 62. This waterproof cap 62 covers the shaft guide 63 up to a medium diameter portion 634.

[0086] For this reason, a gap is formed between the outer peripheral surface of the small diameter portion 635 of the shaft guide 63 and the inner peripheral surface of the waterproof cap 62, facilitating deformation due to pressure applied to the tip surface of the waterproof cap 62. This also makes it possible to prevent adhesion due to infiltrating chemicals, etc.

[0087] The outer circumferential surface of the waterproof cap 62 covering the medium diameter portion 634 of the shaft guide 63 and the outer circumferential surface of the flange portion 623 are in close contact with the inner circumferential surface of the detection hole 612 to ensure liquid tightness. As is clear from Figure 10, the detection hole 612 has a small diameter portion 635 on the tip side and a large diameter portion 633 on the base end side, and the flange portion 623 is located on the tip side of this large diameter portion 633.

[0088] The occlusion detection mechanism 6 is attached to the main frame 3 by a mounting screw 667. At this time, a support member 67 mounted on a circuit board 68 on which other electronic circuits are formed is connected to the connection element 652 of the sensor board 65, so that the pressure detection element 653 of the sensor board 65 and the circuit board 68 are electrically connected. The circuit board 68 is fixed to the main frame 3 by a screw member 681.

[0089] 10, occlusion sensor holding members 43A and 43B are disposed at positions corresponding to the occlusion detection mechanism 6 on the door 4 side. In the following description, as with the occlusion detection mechanism 6, the occlusion sensor holding members 43A and 43B have the same configuration, and therefore will be collectively described as occlusion sensor holding member 43.

[0090] The occlusion sensor holding member 43 is disposed inside the back panel 41 and is a rectangular cylindrical member with a closed tip end and an open base end. A spring fixing protrusion 434 for fixing a compression spring member 433 is formed in the center of the occlusion sensor holding member 43.

[0091] The compression spring member 433 is inserted into the occlusion sensor holding member 43 so that the spring fixing protrusion 434 is inserted into its tip side, and its base end side is placed in a fixing hole formed in the door base 47, so that it is clamped between the spring fixing protrusion 434 and the door base 47.

[0092] Therefore, the occlusion sensor pressing member 43 is biased toward the tip side by the compression spring member 433. As shown in Fig. 1, a pressing protrusion 432 is formed on the tip surface of the occlusion sensor pressing member 43 from top to bottom, corresponding to and facing the infusion tube 100, so that the infusion tube 100 can be further compressed.

[0093] [Water-resistant construction] Next, the drip-proof structure will be described. As shown in Fig. 11, the drip-proof structure in this embodiment is composed of a packing member 7 attached to the door 4 side, a first overhanging structure 32 formed on the main frame 3 so as to surround its outer periphery, a second overhanging structure 34 formed inside the first overhanging structure 32, and a groove structure 33 formed between them.

[0094] 1 and 11, the first canopy structure 32 is formed along the outer periphery of the main frame 3 and surrounds the outer periphery of the main frame 3 except for the lower part of the infusion pump body 2. The side of the main frame 3 where the opening and closing mechanism of the door 4, i.e., the hinge member 301 in FIG. 1, is located, is only covered at the upper part and is discontinued. Needless to say, since it is a drip-proof structure, there is no need to surround the lower part of the infusion pump body 2.

[0095] As shown in FIG. 1, on the door handle 9 side, a waste liquid opening 35 is formed above the lock pin support member 121 so that liquid that has entered the groove structure 33 can be discharged.

[0096] The second overhanging structure 34 is formed inwardly and spaced apart from the first overhanging structure 32, forming a groove structure 33 therebetween. The second overhanging structure 34 is formed inside the first overhanging structure 32 to avoid the area in which the opening and closing mechanism of the door 4, i.e., the hinge member 301 in FIG. 1, etc. are arranged. On the door handle 9 side, the second overhanging structure 34 is bent above the lock pin support member 121 toward the waste liquid opening 35 to guide the waste liquid, and below that, a region 34a is formed along the inside of the first overhanging structure 32, which is slightly higher than the first overhanging structure 32, and ends below the lock pin support member 121.

[0097] 11, a U-shaped overhanging recess 321 corresponding to the tube attachment groove 31 is formed in the upper central position of the first overhanging structure 32. A sealing protrusion is formed inside the overhanging recess 321, protruding from the central portion in the width direction, and this portion holds the infusion tube 100 and cooperates with the packing member 7 described later to prevent the intrusion of liquid matter running down the infusion tube 100.

[0098] Like the first overhanging structure 32, the second overhanging structure 34 also has an overhanging notch 341 formed in correspondence with the tube mounting groove 31. The width of the overhanging notch 341 is also set to a length corresponding to the width of the infusion tube 100, thereby further preventing the intrusion of liquid matter running down the infusion tube 100.

[0099] A drip-proof narrow width portion 311 is formed in the tube mounting groove 31 above the first occlusion detection mechanism 6A below the second overhanging structure 34. The width of the drip-proof narrow width portion 311 is also set to a length corresponding to the width of the infusion tube 100, so that any liquid that may seep in from the second overhanging structure 34 is blocked to some extent, further preventing the intrusion of liquid along the infusion tube 100.

[0100] The packing member 7 is disposed and fixed on the door 4 side, and cooperates with the groove structure 33 to ensure drip-proofing of the infusion pump 1. Specifically, as shown in the cross-sectional view of Fig. 12, the packing member 7 is fixed to the upper part of the door base 47, and the contact rib 73 at the tip of the packing member 7 is brought into contact with the bottom surface of the groove structure 33 of the main frame 3, thereby liquid-tightly sealing the space above the door base 47 and the main frame 3. Note that the contact rib 73 shown in Fig. 12 is actually crushed by the bottom surface of the groove structure 33 and cannot be seen, but is shown for ease of understanding.

[0101] As shown in Figures 13 to 15, packing member 7 is a plate-like member having a certain width and thickness and an overall distorted inverted U-shape or inverted C-shape. Figure 13 is a front view of packing member 7. Figure 14 is a plan view of packing member 7. Figure 15 is a perspective view of packing member 7 as viewed from below.

[0102] The packing member 7 is formed in a shape that follows the groove structure 33 of the main frame 3. Therefore, one bottom end 718 corresponding to the side where the hinge member 301 of the door 4 is arranged is shorter than the other bottom end 717 on the door handle 9 side, and the other bottom end 717 on the door handle 9 side is in a completely hanging position, but the one bottom end 718 is interrupted before hanging down completely.

[0103] The main body 71 of the packing member 7 has a flat upper surface 711 and a lower surface 712, and is formed from an elastic body having a predetermined thickness. It is gently bent 90 degrees via a bend 716 on the hinge member 301 side and extends to one lower end 718, and also is gently bent 90 degrees via a bend 715 on the door handle 9 side and extends to the other lower end 717.

[0104] As shown in Fig. 13, the packing member 7 has a long and narrow strip-shaped adhesion rib 73 that protrudes over the entire area of ​​the packing member 7 at the center in the width direction of the tip surface 714 on the front side (the front side of Fig. 13). The adhesion rib 73 is crushed by contacting the bottom surface of the groove structure 33, and has the function of ensuring airtightness. For this reason, it can be crushed with a moderate force, and has a height that does not create a gap between it and the bottom surface of the groove structure 33.

[0105] A U-shaped tube-storing recess 72 that penetrates vertically is formed in the center of the packing member 7. The tube-storing recess 72 is sized to fit the outer shape of the infusion tube 100 to be stored, but in order to accommodate an infusion tube 100 with a large diameter, a groove 72a is formed in the center of the packing member 7 in the thickness direction by expanding the diameter and width of the outer periphery of the tube-storing recess 72 in a groove shape.

[0106] For this reason, the contact rib 73 branches into upper and lower U-shaped branches near the opening of the tube storage recess 72 and ends at the opening end of the tube storage recess 72. Inside the contact rib 73 branched into U-shaped branches, the end of the groove portion 72a appears.

[0107] As shown in Figures 13 and 15, the fixing structure of the packing member 7 is such that a front fixing rib 75 is formed in the base end side 1 / 3 of the lower width direction so as to protrude downward in a plate shape that conforms to the shape of the packing member 7, and a rear fixing rib 76 is formed in the lower edge of the base end face 713 so as to protrude downward in a plate shape.

[0108] As clearly shown in FIG. 12, the front fixing rib 75 has a longer protruding length than the rear fixing rib 76, and is capable of receiving the load of the packing member 7 on the tip side and holding it stably.

[0109] As shown in Fig. 14, the packing member 7 is divided into a tip side portion 71B and a rear side portion 71A with the base end side 1 / 3 of the width as the midpoint. The front fixing rib 75 is formed downward from this midpoint. The tip side portion 71B is formed in a tapered shape with a thickness that gradually decreases slightly toward the edge.

[0110] The top surfaces 711 of the leading end portion 71B and the trailing end portion 71A are both inclined toward the front and rear ends, so that any liquid that enters is guided to the front and rear ends. At a joint 71C between the leading end portion 71B and the trailing end portion 71A, the height of the trailing end portion 71A is slightly higher, forming a step.

[0111] The tip side portion 71B is formed with a vertical waterproof rib 74 that protrudes upward from its tip edge. The vertical waterproof rib 74 is formed over the entire tip edge of the tip side portion 71B, including the outer periphery of the tube storage recess 72, so that any liquid that enters is guided along the vertical waterproof rib 74 to both lower ends 717, 718.

[0112] A U-shaped recess 77 is formed in the center of the rear end side portion 71A to avoid the operation indicator storage portion, which is a structure of the door 4. Also, the front fixing rib 75 is formed with a U-shaped bent portion corresponding to this.

[0113] The material for the packing member is preferably a resin material with a certain level of flexibility and elasticity, specifically, styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), and for special rubbers, synthetic rubber resins such as acrylic rubber (ACM), fluororubber (FKM), silicone rubber (Q), etc. Natural rubber may also be used in some cases.

[0114] [Pump tube anti-wandering structure] Next, the structure for preventing meandering of the pump section tube will be described. As shown in Fig. 16, the pump section opening 8 of the main frame 3 arranged on the top of the peristaltic pump 10 shown in Fig. 1 has barrier protrusions 82 formed on the underside of both sides of the pump section opening 8. A reinforcing rib is formed around the periphery of the pump section opening 8, and a pump fixing screw hole 320 for fixing the main frame 3 and the peristaltic pump 10 is formed in the vicinity of the reinforcing rib.

[0115] A thick tube mounting groove forming portion 310 for forming the tube mounting groove 31 is formed on the back surface around the pump portion opening 8.

[0116] As shown in FIG. 17, the barrier protrusion 82 regulates the gap t from the upper end of the finger 10n of the peristaltic pump 10 that has risen to the top dead center to the lower surface of the barrier protrusion 82 to a predetermined length.

[0117] 18, for example, it is possible to prevent the infusion tube 100 from meandering and getting caught between the back side of the main frame 3 and the fingers 10n, which causes the pump to malfunction. In other words, the barrier protrusion 82 prevents the infusion tube 100 from meandering, and guides the infusion tube 100 so that it is sandwiched between the back plate 45 and the fingers 10n and crushed normally.

[0118] The gap t from the top end of the finger 10n of the peristaltic pump 10 to the underside of the barrier protrusion 82 should be set to a gap large enough to prevent the infusion tube 100 from entering, for example, approximately 1 / 8 to 0 (as small as technically possible) of the outer diameter of the infusion tube 100 with the minimum expected outer diameter.

[0119] On the other hand, if the infusion tube 100 meanders above the main frame 3, the infusion tube 100 will be pinched between the main frame 3 and the door base 47, preventing normal pump operation.

[0120] At this time, the door 4 is raised from the normal closed position, but with the door handle structure shown in FIG. 21B, the door 4 may be locked even in this state.

[0121] As shown in Fig. 19, the door handle 9 has a handle operating portion 93, a handle main body 91, an inner guide wall 95 and an outer guide wall 94 formed on the handle main body 91, and a guide groove bottom surface 96 sandwiched between them. Note that Fig. 19 is a partially see-through perspective view showing the relationship between the door handle 9 and the fixing pin, and other structures have been omitted for ease of understanding.

[0122] A locking operation is performed by capturing a lock pin 12 fixed to the infusion pump main body 2 side inside the inner guide wall 95 and the outer guide wall 94. The lock pin 12 is fixed to the main frame 3 by a lock pin support member 121. The door handle 9 is supported by a handle rotation shaft 92 and rotates around this shaft.

[0123] 20, the operation of capturing the lock pin 12 with the door handle 9 is performed when the handle operating portion 93 is open and the outer guide wall 94 of the guide groove reaches a position where it can engage with the lock pin 12. This position is normally defined by the distance L1 (hereinafter referred to as the capturing distance) from the axial center of the handle rotating shaft 92 when the door 44 is in the proper closed position to the axial center of the lock pin 12 when the outer guide wall 94 begins to engage with the lock pin 12.

[0124] When the handle operating unit 93 is closed, the door handle 9 rotates counterclockwise around the handle rotating shaft 92 in Fig. 20, and the lock pin 12 is guided to the end of the guide groove. At this time, since the distance L2 from the center of the handle rotating shaft 92 to the center of the lock pin 12 is shorter than the capture distance L1, the door 4 is pressed against the infusion pump body 2 and comes into close contact.

[0125] However, in the door handle structure shown in FIG. 21B, since a locking claw 94a is formed at the tip of the outer guide wall 94 compared to the door handle structure shown in FIG. 21A, the capture distance L1 is longer, and even if the door 4 is in an insufficiently closed position by pinching the infusion tube 100, the lock pin 12 may be captured and the locking operation may be performed.

[0126] In this embodiment, the door handle 9 has a structure without a locking claw 94a as shown in Fig. 21A, and the capture distance L1 is shortened so that the door 44 can be locked only when it is in the proper closed position. This makes it possible to prevent malfunction of the infusion pump 1 caused by meandering of the infusion tube 100.

[0127] [Door 4 Wiring Cover] A connection cable is arranged between the door 4 and the infusion pump main body 2 to electrically connect them and to transmit and receive electrical signals between various operating switches provided on the door 4, or between a display device and a control device (not shown) of the infusion pump main body 2.

[0128] In this embodiment, this connection cable extends from the outside of the second overhanging structure 34 formed between a pair of hinge members 301 of the infusion pump main body 2 shown in Figure 1, curves inwardly, toward the door 4, bends, and is introduced into the interior of the door from the corresponding edge of the door base 47, and is connected to an electrical circuit board on which a display device, etc. (not shown) is mounted.

[0129] Typically, a flat cable such as a flexible flat cable is used for this connection cable, but as the door 4 is repeatedly opened and closed, the connection cable extending between the infusion pump body 2 and the door 4 can gradually protrude to the outside, posing a risk of breaking.

[0130] For this reason, a cover body may be provided on the infusion pump main body 2 to cover the upper part of the connection cable extending toward the door 4 and guide it laterally, thereby preventing the connection cable from floating up and preventing direct access from the outside, thereby protecting the connection cable.

[0131] [Actions and Effects] The effects of this embodiment will be described below.

[0132] According to the medical infusion pump 1 of this embodiment, since the clamp member (52) has a curved portion 524 on its tip surface, the opening degree of the clamp member (52) when pressed against the inclined surface of the release projection 42, i.e., the rate of the opening angle, can be reduced (smaller), and the clamp member (52) can be prevented from opening more than necessary. Therefore, when the door 4 is opened by mistake, for example, the clamp member (52) can be quickly closed, and free flow can be prevented.

[0133] Furthermore, when the door 4 is closed, the opening operation of the clamp member (52) proceeds little by little, so that the fingers 10n first close the infusion tube 100, thereby preventing free flow.

[0134] Furthermore, according to the medical infusion pump 1 of this embodiment, the tip surface of the clamp member (52) is formed with the inclined surface portion 523 continuous with the curved surface portion 524, so that the opening degree of the clamp member (52) can be easily set. That is, when the inclined surface of the release projection 42 contacts and presses the tip surface, the curved surface portion 524 opens the clamp member 52 and the opening operation is completed by the inclined surface portion 523, so that the degree of opening of the clamp member 52 can be adjusted by adjusting the position of the inclined surface portion 523. This makes it possible to prevent the clamp member (52) from opening more than necessary, to quickly close the clamp member (52), and to prevent free flow.

[0135] According to the medical infusion pump 1 of this embodiment, the tip surface of the clamp member (52) has a curved portion 524, so that the portion that comes into contact with the inclined surface of the release protrusion 42 has a curved shape, making it less likely to damage the inclined surface of the release protrusion 42 and preventing damage.

[0136] According to the medical infusion pump 1 of this embodiment, a gap is formed between the outer peripheral surface of the small diameter portion 635 of the shaft guide 63 of the occlusion detection mechanism 6 and the inner peripheral surface of the waterproof cap 62, facilitating deformation due to pressure applied to the tip surface of the waterproof cap 62. Therefore, even if a medicinal solution or the like enters the occlusion detection mechanism 6 and solidifies, the operation of the occlusion detection mechanism 6 is not easily hindered.

[0137] According to the medical infusion pump of this embodiment, the shaft 64 of the occlusion detection mechanism 6 is made of metal and therefore is less likely to deform, and the pressure of the infusion tube 100 can be transmitted to the pressure detection element 653 without loss.

[0138] According to the medical infusion pump of this embodiment, the occlusion sensor pressing member 43 of the occlusion detection mechanism 6 is formed with a single pressing protrusion 432 that faces the infusion tube 100 from above and below, so that the infusion tube 100 can be compressed more firmly, making it easier for the pressure detection element 653 to detect the pressure of the infusion tube 100.

[0139] According to the medical infusion pump 1 of this embodiment, a first overhanging structure 32 is formed on the outer periphery of the main frame 3, and a second overhanging structure 34 is formed inside it with a predetermined space therebetween, making it difficult for liquid to enter from the outside.

[0140] According to the medical infusion pump 1 of this embodiment, the gasket member 7 is fixed to the upper part of the door base 47, and its tip is in close contact with the bottom surface of the groove structure 33 formed by the first eaves structure 32 and the second eaves structure 34, making it even more difficult for liquids to enter from the outside.

[0141] According to the medical infusion pump 1 of this embodiment, a U-shaped tube storage recess 72 that penetrates vertically is formed in the center of the packing member 7 and is set to a size that matches the outer shape of the infusion tube 100 to be stored. Furthermore, a groove portion 72a is formed by expanding the diameter and width of the tube storage recess 72 in a groove-like shape on the outer periphery, so that the packing member 7 can adhere closely to the infusion tube 100 and can also prevent the intrusion of liquid that runs down the infusion tube 100.

[0142] [Variations] A modification of this embodiment will be described below.

[0143] In this embodiment, the clamp lever 52 is shown as a horizontally long rectangular plate-like body, but the present invention is not limited to this. As long as it can hold 100, it may be any rod or round bar, and when it is plate-shaped or block-shaped, the shape of the body other than the tip surface can be freely set.

[0144] In this embodiment, a structure in which the clamp lever 52 rotates around the clamp rotation axis 601 to open and close is shown as an example, but the present invention is not limited to this, and a structure in which it moves in a straight line by applying, for example, a linear bearing or a linear moving stage is also possible.

[0145] In this embodiment, the latch lever 53 and the release lever 54 are described as examples of the configuration for opening and closing the clamp lever 52 when the door 4 is open, but the present invention is not limited to this, and the clamp lever 52 may be opened and closed by other mechanisms.

[0146] In this embodiment, a configuration having a latch lever 53 and a release lever 54 has been described as an example of a configuration for opening and closing the clamp lever 52 when the door 4 is open, but the present invention is not limited to this and these may be omitted, in which case a gripping portion may be provided on the clamp lever 52 so that it can be opened and closed directly by hand. [Explanation of symbols]

[0147] 2 Infusion pump body 3. Mainframe 4 Door 5 Tube clamp (tube clamp mechanism) 10 Peristaltic pump (pump section) 42 Release protrusion 52 Clamp lever (clamp member) 100 Infusion tube 514 Supporting member 523 Slope 524 Curved surface part

Claims

1. A medical pump that delivers a liquid through an infusion tube, an infusion pump body having a pump portion; a door disposed so as to be freely opened and closed relative to the infusion pump body; a tube clamp mechanism that closes the infusion tube when the door is open and releases the blockage of the infusion tube when the door is closed, The tube clamp mechanism includes: A release protrusion disposed on an inner surface of the door and having an inclined surface at a tip thereof; a clamp member that is disposed on the infusion pump body and has a curved portion on its tip surface, and closes against a receiving member to block the infusion tube when the inclined surface of the release protrusion is not pressing against the curved portion, and opens against the receiving member to release the infusion tube when the inclined surface of the release protrusion is pressing against the curved portion.

2. the clamp member has a slope portion formed continuously with the curved surface portion on the tip surface, 2. The medical pump according to claim 1, wherein the opening degree of the clamp member is maximized when the tip surface of the release projection that contacts the inclined surface is switched from the curved surface portion to the inclined surface portion.

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