JP4452400B2 - Press - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressing device that presses a member to be pressed.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a chemical solution injector that automatically injects a chemical solution by using a syringe. As shown in FIG. 5, in this chemical solution injector, a chemical solution is injected into a patient by pressing a plunger 84 at a constant speed with a pusher 83 against an outer cylinder 82 of a syringe 81 containing a chemical solution.
[0003]
More specifically, when the motor 85 is driven, the feed screw 86 provided below the syringe 81 rotates. The rotation of the feed screw 86 is transmitted to a half nut 88 as shown in FIG. 6, and the half nut 88 slides linearly with respect to a guide shaft 87 extending along the feed screw 86. As a result, the pusher 83 connected to the half nut 88 so as to be movable in the same direction presses the plunger 84 as the half nut 88 moves.
[0004]
Here, the half nut 88 will be described in more detail.
As shown in FIG. 6, the half nut 88 is attached to be rotatable about the axis of the guide shaft 87. In addition, a thread surface is provided so as to face the substantially half circumference of the thread surface of the feed screw 86. A tension spring 89 is connected to the half nut 88, and the thread surface of the half nut 88 is engaged with the thread surface of the feed screw 86 by the urging force of the tension spring 89. Accordingly, the rotation of the feed screw 86 is transmitted to the half nut 88 by the urging force of the tension spring 89, and the pusher 83 is moved.
[0005]
On the other hand, when the half nut 88 is rotated against the urging force of the tension spring 89 by the lever 90 at the upper part thereof, the meshing with the feed screw 86 is released. Then, the linkage between the half nut 88 and the feed screw 86 is cut off, and the pusher 83 can be manually moved linearly.
[0006]
[Problems to be solved by the invention]
By the way, it is the feed screw 86 and the half nut 88 that convert the rotational motion transmitted from the motor 85 into a linear motion, and the thread surface of the half nut 88 corresponds to its substantially half circumference with respect to the feed screw 86. Yes. The meshability between the thread surface of the feed screw 86 and the thread surface of the half nut 88 is determined by the spring force of the tension spring 89. Conventionally, a tension spring 89 capable of operating the lever 90 with a force of about 60 N to 80 N has been used.
[0007]
Conventionally, even when the tension spring 89 having the above-described force is used, the operability is sufficiently ensured. However, recently, the lever 90 is operated with a smaller force to engage the feed screw 86 and the half nut 88. It is desirable to be able to cancel the alignment.
[0008]
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a pressing device capable of releasing meshing between a feed screw and a half nut, that is, a meshing member with a small force.
[0009]
[Means for Solving the Problems]
  The invention according to claim 1 is a feed screw that is rotated by driving of the drive unit, and a conversion unit that converts rotation of the feed screw into linear motion,An opening / closing operation mechanism for operating the conversion means;And a slide mechanism that is movable along the longitudinal direction of the feed screw in linkage with the linear motion of the conversion means, and is a pressing device that presses a member to be pressed by the movement of the slide mechanism. A pair of engagement members that have screw surfaces corresponding to the screw surfaces of the feed screw, and are engaged with the feed screw so as to be disengageable from both sides, and an urging member that urges the engagement members in a direction facing each other. And withThe opening / closing operation mechanism includes a cam that engages and disengages the engagement member with respect to the feed screw, a connection shaft that is a rotation center of the cam, and an operation lever that rotates the connection shaft. Comprises a slide block that is integrated with the conversion means and is slidably movable on the feed screw, a pusher that presses the pressed member, and a slide cylinder that connects the slide block and the pusher. The connecting shaft is inserted into the slide cylinder, and the operation lever is attached to the pusher.It is a summary.
[0010]
  ContractClaim2The invention described in claim1The screw surfaces of the respective meshing members are respectively formed corresponding to the half circumferences of the opposing feed screws, and when both the mesh members mesh the feed screws, the both screw surfaces are the entire outer circumference of the feed screw. The gist is to engage with each other.
[0011]
  Claim3The invention described in claim 1OrClaim2The two meshing members are pivotally mounted so as to intersect each other in the middle thereof, and the cam is disposed between the end portions of the meshing member on the side opposite to the screw surface.
[0012]
  Claim4The invention described in claim 1 to claim 13The gist of the invention is that the urging member is disposed between the two meshing members.
  Claim5The invention described in claim 1 to claim 14The gist of the invention is that the pressed member is a plunger of a syringe that is pressed for injecting a chemical solution.
[0013]
  (Function)
  According to the first aspect of the present invention, the meshing member that meshes the feed screw from both sides is urged by the urging member in a direction facing each other. For this reason, when a force is applied to the meshing member in the radial direction of the feed screw due to the rotation of the feed screw, even if the screw surface of one of the meshing members attempts to skip the screw surface of the feed screw, The meshing member is attracted to the feed screw side by the biasing member, and comes to mesh strongly with the feed screw. Therefore, the tooth skipping of the meshing member does not occur without using a biasing member having a large biasing force. Since it is not necessary to use a biasing member having a large biasing force in this way, it is possible to release the engagement between the feed screw and the meshing member with a small force.Further, the meshing release of the meshing member with respect to the feed screw is realized by the operation of the cam of the opening / closing operation mechanism.
[0014]
  ContractClaim2According to this invention, when the feed screw is sandwiched between the meshing members each having the thread surface formed corresponding to the half circumference of the feed screw, the thread surface of the meshing member is meshed over the entire outer periphery of the feed screw. The Therefore, the contact area of the screw surface of the meshing member with respect to the feed screw is the largest.
[0015]
  Claim3According to this invention, the two meshing members that are axially attached so as to intersect with each other are spread apart by the operation of the cam disposed therebetween, and the meshing between the feed screw and the meshing member is released.
[0016]
  Claim4According to this invention, it is not necessary to consider an extra space for an urging member by arrange | positioning an urging member between a meshing member.
  Claim5According to the invention, the pressing device is used for pressing the plunger of the syringe that is pressed for injecting the chemical solution.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is embodied in a medical solution injector will be described with reference to FIGS.
[0018]
FIG. 1 is a cross-sectional view of a chemical solution injector.
A motor 12 as drive means is fixedly supported inside the case 11 of the chemical injector, and a feed screw 13 is operatively connected to the output shaft of the motor 12. The feed screw 13 is rotatably supported at both ends on both support walls 14a of the support portion 14 fixed to the ceiling surface of the case 11. Below the feed screw 13, a guide bar 15 extends in parallel with the feed screw 13, and both ends thereof are fixed to the support wall 14a. In the present embodiment, the number of the guide bars 15 is one, but it is of course possible to provide a plurality of guide bars.
[0019]
A slide block 16 is slidably provided on the feed screw 13 and the guide rod 15. That is, as shown in FIG. 4, in the slide block 16, the feed screw 13 and the guide rod 15 are inserted into the first and second guide holes 17 and 18 that are transparently provided in the thickness direction.
[0020]
A slide nut 19 is connected to the side of the slide block 16 opposite to the motor. The slide nut 19 has screw surfaces 43 and 53 corresponding to the screw surface 13 a of the feed screw 13, and can be engaged with and disengaged from the feed screw 13.
[0021]
Here, the slide nut 19 will be described in detail.
The slide nut 19 includes a pair of first and second half nuts 41 and 51 as engagement members and a tension spring 42 as an urging member.
[0022]
As shown in FIGS. 3A and 3B, each half nut 41, 51 is formed in a substantially crank shape, and a screw surface 43 corresponding to a half-circumferential portion of the feed screw 13 is formed at the tip thereof. 53 are curved. The side surfaces of the first and second half nuts 41 and 51 opposite to the threaded surfaces 43 and 53 are cam driven surfaces 44 and 54 for transmitting the operation of the cam 28 to the half nuts 41 and 51 themselves.
[0023]
Each of the half nuts 41 and 51 is attached to a support shaft 45 formed on the slide block 16 so as to be openable and closable with the central portions thereof intersecting each other. Moreover, the center part of each half nut 41 and 51 is made into the thin part 41a and 51a recessedly provided so that it might mutually face. The thin-walled portions 41a and 51a are engaged with each other so that the screw surfaces 43 and 53 of the half nuts 41 and 51 face each other. When the first and second half nuts 41 and 51 are closed, the half nuts 41 and 51 are engaged with the feed screw 13 from both sides opposite to each other by 180 degrees, and the screw surfaces 43 and 53 are fed. The entire outer periphery of the screw 13, that is, the entire periphery is meshed.
[0024]
A tension spring 42 is interposed between the first and second half nuts 41, 51 at an intermediate position between the support shaft 45 and the screw surfaces 43, 53, so that the half nuts 41, 51 are closed in the closing direction (that is, each other). Energized in the direction facing each other. That is, the first and second half nuts 41 and 51 are formed so that the storage holes 46 and 56 are positioned in a straight line when the half nuts 41 and 51 are closed. The ends of the tension springs 42 are fixed to each other. For this reason, the first and second half nuts 41 and 51 are attracted to each other by the tension spring 42.
[0025]
Between the cam driven surfaces 44 and 54 of the first and second half nuts 41 and 51, a cam 28 that is interlocked with the rotation of the operation lever 25 described later is disposed. The cam 28 rotates about a connecting shaft 27 described later as a rotation center. That is, the cam 28 can rotate between a non-interference position as shown in FIG. 3A and an interference position as shown in FIG. The non-interference position is a position that does not interfere with the half nuts 41 and 51 so as to keep both the half nuts 41 and 51 closed, and the interference position contacts the cam driven surfaces 44 and 54 and In this position, the nuts 41 and 51 are opened against the urging force of the spring 42.
[0026]
In the present embodiment, the slide nut 19 (the first and second herb nuts 41 and 51) constitutes a conversion means, and the cam driven surfaces 44 and 54 correspond to the end portions on the counter screw surface side. The screw surface 13a of the feed screw 13 and the screw surfaces 43 and 53 of the slide nut 19 are so-called round screws.
[0027]
A slide cylinder 21 extending along the longitudinal direction of the feed screw 13 is fixed to the side of the slide block 16 opposite to the slide nut 19. The slide cylinder 21 communicates with the slide nut 19 side through a communication hole 22 (see FIG. 4) that is provided in the thickness direction in the slide block 16. The slide cylinder 21 protrudes to the outside of the case through the support wall 14 a and the side wall 11 a of the case 11, and the tip portion is connected to the pusher 23. As a result, the rotation operation of the feed screw 13 is converted into a linear motion by the slide nut 19. The slide nut 19 is slid along the longitudinal direction with respect to the feed screw 13 integrally with the slide block 16, the slide cylinder 21, and the pusher 23. The slide block 16, slide nut 19, slide cylinder 21, and pusher 23 constitute a slide mechanism.
[0028]
In addition, a connecting shaft 27 having the cam 28 is rotatably supported in the communication hole 22 of the slide block 16 at the tip of the slide nut 19 side. The connecting shaft 27 is inserted in the slide cylinder 21 and is also rotatably supported by the pusher 23.
[0029]
On the other hand, as shown in FIG. 2, an operating lever 25 is attached to the pusher 23, and first and second locking portions 26a and 26b for locking the operating lever 25 are integrally formed. ing. The first and second locking portions 26 a and 26 b are formed so as to protrude toward the anti-sliding cylinder 21 side of the pusher 23, and are disposed so as to face each other in a direction perpendicular to the moving direction of the pusher 23. A recess 26c is formed between the first and second locking portions 26a and 26b. One end of the connecting shaft 27 protrudes into the recess 26c, and the operation lever 25 is integrally fixed to the same end. The operation lever 25 has a first position (shown by a solid line in FIG. 2) locked to the first locking portion 26a and a second position (shown by a two-dot chain line in FIG. 2) locked to the second locking portion 26b. It is possible to rotate between them.
[0030]
The non-interference position of the cam 28 (see FIG. 3A) corresponds to the first position of the operation lever 25 (shown by a solid line in FIG. 2), and the interference position of the cam 28 (FIG. 3B). 2) corresponds to the second position of the operation lever 25 (indicated by a two-dot chain line in FIG. 2).
[0031]
In the present embodiment, the operation lever 25, the connecting shaft 27, and the cam 28 constitute an opening / closing operation mechanism.
Outside the case 11, in addition to the pusher 23, a liquid medicine injection operation of the syringe 31 and a monitoring operation device (not shown) for monitoring the injection state, a mounting portion 30 on which the outer cylinder 32 of the syringe 31 is mounted, etc. Is provided.
[0032]
The syringe 31 includes an outer cylinder 32 and a plunger 33 as a pressed member. The outer cylinder 32 is detachably attached to the mounting portion 30, and the rear end portion of the plunger 33 is hooked on the hooking portion 34 of the pusher 23. The plunger 33 is slidable with respect to the outer cylinder 32 as the pusher 23 is pressed. Further, a flexible injection pipe (not shown) connected to the injection needle is connected to the distal end portion of the outer cylinder 32.
[0033]
Next, the operation of the chemical injector configured as described above will be described.
When using the chemical solution injector, first, the outer cylinder 32 of the syringe 31 containing the chemical solution is placed on the placement portion 30 and the plunger 33 of the syringe 31 is engaged with the latching portion 34 of the pusher 23. Let At this time, the position of the rear end portion of the plunger 33 differs depending on the volume of the chemical solution and the size of the syringe 31. For this reason, the pusher 23 is moved manually to adjust the position.
[0034]
In manual position adjustment of the pusher 23, the operator rotates the operation lever 25 from the first position (solid line in FIG. 2) to the second position (two-dot chain line in FIG. 2). Then, the cam 28 located at the non-interference position shown in FIG. 3A presses and contacts the cam driven surfaces 44 and 54 of the first and second half nuts 41 and 51 via the connecting shaft 27. As a result, as shown in FIG. 3B, the cam 28 pushes both the cam driven surfaces 44 and 54 and is positioned at the interference position.
[0035]
Along with this, the half nuts 41, 51 perform an opening operation with the support shaft 45 as the rotation center against the urging force of the tension spring 42. Then, the screw surfaces 43 and 53 of the first and second half nuts 41 and 51 are detached from the screw surface 13a of the feed screw 13, and the meshing is released.
[0036]
As a result, the pusher 23 that is integrally connected to the slide nut 19 (first and second half nuts 41 and 51) via the slide block 16 and the slide cylinder 21 extends in the longitudinal direction of the feed screw 13 and the guide rod 15. And can be moved manually. In this way, the pusher 23 is placed at a desired position and the plunger 33 is set.
[0037]
At this time, the opening operation of the half nuts 41 and 51 is performed by rotating the cam 28 based on the rotation operation of the operation lever 25 and pushing and spreading the cam driven surfaces 44 and 54. For this reason, the operation of the two half nuts 41 and 51 is easily performed by the single operation lever 25. Further, for example, unlike the mechanism in which the half nuts 41 and 51 are separately opened without disposing the cam 28 between the both half nuts 41 and 51, it contributes to space saving.
[0038]
Now, after the pusher 23 is manually slid and placed at a desired position, the hand is released from the operation lever 25. Then, due to the urging force of the tension spring 42, both the half nuts 41, 51 move in the closing direction about the support shaft 45 as the rotation center, and the cam 28 is moved from the interference position to the non-interference position via the cam driven surfaces 44, 54. Rotate to As a result, the operating lever 25 is automatically returned from the second position to the first position via the connecting shaft 27.
[0039]
Thereafter, in the chemical solution injector in which the syringe 31 is set, the motor 12 is driven to perform the chemical solution injection operation. That is, the feed screw 13 is rotated by driving the motor 12, and the slide nut 19 starts to linearly move along the feed screw 13 in the arrow A direction at a predetermined speed.
[0040]
Here, since the slide block 16, the slide cylinder 21, and the pusher 23 are connected to the slide nut 19, the pusher 23 presses the plunger 33 at a predetermined speed. As a result, the drug solution in the syringe 31 is pushed out at a constant flow rate and injected into the patient via the infusion pipe and the injection needle.
[0041]
At this time, the slide nut 19 is sandwiched from both sides of the feed screw 13 by applying a biasing force of the spring 42 to the pair of first and second half nuts 41 and 51. Therefore, even if the first and second half nuts 41 and 51 receive a force in the radial direction of the feed screw 13 during the rotation of the feed screw 13, the screw surfaces 43 and 53 of the half nuts 41 and 51 and the feed screw No tooth jump occurs between the thirteen screw surfaces 13a.
[0042]
More specifically, the feed screw 13 always receives the frictional force generated by the half nuts 41 and 51. Then, for example, it is assumed that the first half nut 41 receives a radial force via the feed screw 13 and moves away from the feed screw 13 due to this frictional force. At this time, even if the screw surface 43 of the first half nut 41 attempts to skip teeth (ie, disengage) from the feed screw 13, the screw surface 53 of the second half nut 51 does not move to the first half of the tension spring 42. Due to the urging force toward the nut 41, the screw surface 13 a of the feed screw 13 is more strongly engaged.
[0043]
Further, the screw surfaces 43 and 53 of the half nuts 41 and 51 are respectively curved so as to correspond to the half circumference of the feed screw 13. When the half nuts 41 and 51 are closed, the screw surfaces 43 and 53 are curved. 53 meshes over the entire circumference of the feed screw 13. For this reason, unlike the case where the feed screw 13 is partially meshed with the first and second half nuts 41 and 51, the meshing area is wide and the meshing property is enhanced.
[0044]
As a result, even if the spring 42 having a smaller spring force than the conventional one is used, the feed screw 13 and the first and second half nuts 41 and 51 mesh with each other without being affected by the radial force, and the smooth pusher 23 Movement is realized. Further, since a spring having a small spring force can be used, the burden on the operator can be reduced when the operation lever 25 is operated.
[0045]
Here, when the result using the chemical | medical solution injector in this embodiment is shown actually, even if it uses the tension | pulling spring 42 which can operate the operation lever 25 with the force of about 10N, the screw surface 13a of the feed screw 13 and No tooth jumping occurred between the screw nuts 43 and 53 of the slide nut 19 (first and second half nuts 41 and 51), and the chemical liquid injection operation was suitably performed. And, when engaging with the feed screw with only one half nut in the conventional configuration, even if a tension spring that can operate the lever 90 with a force of about 30 N is used, the screw surface of the feed screw Tooth jump occurs between the threaded surface of the half nut. For this reason, in the conventional configuration, this value of about 10 N cannot be obtained.
[0046]
In this embodiment, the screw surface 13a of the feed screw 13 and the screw surfaces 43 and 53 of the slide nut 19 are round screws that have a higher possibility of tooth skipping compared to, for example, square screws. It was used suitably without doing.
[0047]
Therefore, according to the above embodiment, the following effects can be obtained.
(1) In the above embodiment, the first and second half nuts 41 and 51 that convert the rotation of the feed screw 13 into a linear motion are opposed to each other by the tension spring 42 so that the pusher 23 presses the plunger 33. The feed screw 13 was sandwiched from both sides by urging in the direction (closing direction). For this reason, when force is applied to both the half nuts 41 and 51 in the radial direction of the feed screw 13, for example, the screw surface 43 of the first half nut 41 tries to skip the screw surface 13 a of the feed screw 13. Even so, the second half nut 51 is attracted to the feed screw 13 side (first half nut 41 side) by the tension spring 42, and the feed screw 13 is strongly engaged. Accordingly, tooth skipping of each half nut 41, 51 can be prevented.
[0048]
(2) Further, since it becomes possible to use the tension spring 42 having a spring force smaller than that of the prior art, the operation of releasing the meshing between the feed screw 13 and the half nuts 41 and 51 to manually move the pusher 23 is performed. A person can operate the operation lever 25 with a small force.
[0049]
(3) In the above embodiment, the operation lever 25 is operated, and the cam 28 pushes and spreads the cam driven surfaces 44 and 54 of the half nuts 41 and 51, and the first and second half nuts 41 and 51 and the feed screw. 13 mesh release was performed. For this reason, for example, compared with the case where each half nut 41, 51 is opened using a link mechanism or the like, the opening and closing operation of both half nuts 41, 51 is performed while saving space. Can do.
[0050]
Further, since the cam 28 is disposed between the half nuts 41 and 51, the two half nuts 41 and 51 can be easily operated by the single lever 25.
(4) In the above embodiment, the thread surfaces 43 and 53 of the first and second half nuts 41 and 51 are curved to correspond to the half circumference of the feed screw 13, respectively, and the first and second half nuts 41 and 51 are formed. In the closed state, both screw surfaces 43 and 53 mesh with each other over the entire circumference of the feed screw 13. Therefore, the engagement area with the feed screw 13 can be maximized, and the engagement between the half nuts 41 and 51 and the feed screw 13 can be enhanced.
[0051]
(5) In the above-described embodiment, the tension spring 42 is disposed in the accommodation holes 46 and 56 of the first and second half nuts 41 and 51, and is urged between the half nuts 41 and 51 in the closing direction. For this reason, space saving can be achieved compared with the case where it arrange | positions, for example to the exterior of the 1st and 2nd half nuts 41 and 51, and energizes so that both the half nuts 41 and 51 may be closed. .
[0052]
(6) In the above embodiment, the screw surface 13a of the feed screw 13 and the screw surfaces 43 and 53 of the slide nut 19 are round screws that have a high possibility of tooth jumping compared to, for example, a square screw. The first and second half nuts 41 and 51 are engaged with each other from both sides, so that the tooth can be suitably used without causing tooth skipping. Therefore, compared with the case where the square screw is used, it is possible to realize a chemical injector that does not generate tooth skipping at a low cost. Further, as compared with the case where square screws are used for the screw surfaces 13a, 43, 53, smooth movement of the pusher 23 can be realized.
[0053]
(7) In the above embodiment, since the cam 28 is disposed between the cam driven surfaces 44 and 54 on the opposite screw surfaces 43 and 53 side of the half nuts 41 and 51, between the end portions on the screw surfaces 43 and 53 side. Unlike the arrangement, the meshing of the feed screw 13 and the half nuts 41 and 51 can be released with a small force.
[0054]
In addition, you may change the said embodiment as follows.
In the above embodiment, the tension spring 42 is disposed between the first and second half nuts 41 and 51, and both the half nuts 41 and 51 are biased in the closing direction, but instead of the tension spring 42. A compression spring may be used to bias in the closing direction. For example, a pair of compression springs having one end locked to the slide block 16 and the other end engaged with the half nuts 41 and 51, respectively. Even if it does in this way, tooth skip does not generate | occur | produce by meshing the feed screw 13 from both sides.
[0055]
In the above embodiment, the tension spring 42 is disposed in the storage holes 46 and 56 of the first and second half nuts 41 and 51 at the intermediate position between the support shaft 45 and the screw surfaces 43 and 53. You may arrange | position between the cam driven surfaces 44 and 54 of 41,51. Further, the accommodation holes 46 and 56 may be omitted, and the tension spring 42 may be attached to the outer surface side of the half nuts 41 and 51.
[0056]
In the above embodiment, the half nuts 41 and 51 are formed in a substantially crank shape and axially attached so as to intersect with each other. However, the half nuts 41 and 51 are formed in a substantially straight shape and arranged in parallel to each other, and the feed screw 13 is sandwiched therebetween. You may make it an aspect.
[0057]
In the above embodiment, the thread surfaces 43, 53 of the first and second half nuts 41, 51 are curved corresponding to the half circumference of the feed screw 13, but are curved corresponding to only a part of the feed screw 13. May be. In this case, even when both the half nuts 41 and 51 sandwich the feed screw 13, the feed screw 13 is not meshed over the entire circumference but is partially meshed. Even if it does in this way, a tooth skip does not generate | occur | produce by meshing from the both sides of the feed screw 13. FIG.
[0058]
In the above-described embodiment, the cam driven surfaces 44 and 54 of the half nuts 41 and 51 are expanded by the rotation of the cam 28 to release the meshing between the first and second half nuts 41 and 51 and the feed screw 13. The half nuts 41 and 51 may be operated using a link mechanism having a mechanism for opening and closing both the half nuts 41 and 51.
[0059]
In the above embodiment, the screw surface 13a of the feed screw 13 and the screw surfaces 43 and 53 of the half nuts 41 and 51 are round screws, but may be square screws. If it does in this way, tooth skip of feed screw 13 and half nuts 41 and 51 can be prevented further. Further, for example, a triangular screw or a trapezoidal screw may be used.
[0060]
In the above embodiment, the cam 28 is disposed between the cam driven surfaces 44 and 54 corresponding to the end portions on the anti-screw surfaces 43 and 53 side. May be.
[0061]
In the above embodiment, the pressing device is embodied as a chemical solution injector for injecting the chemical solution by pressing the plunger 33 of the syringe 31, but the pressed member is pressed by moving the pusher 23 at a constant speed. It may be embodied in other devices.
[0062]
【The invention's effect】
  As described above in detail, according to the first aspect of the present invention, the engagement between the feed screw and the engagement member can be released with a small force.Further, the release of the engagement between the engagement member and the feed screw can be easily realized by the operation of the cam of the opening / closing operation mechanism.
[0063]
  ContractClaim2According to the invention of claim1'sIn addition to the effects of the invention, when both the meshing members mesh with the feed screw, the screw surfaces of both the meshing members are meshed over the entire outer periphery of the feed screw. The contact area is the largest, and the meshing property between both members can be enhanced.
[0064]
  Claim3According to the invention of claim 1,OrClaim2In addition to the effect of the invention, the meshing member can be simply released from engagement only by using one cam.
[0065]
  Claim4According to the invention, claims 1 to3In addition to the effect of any one of the inventions, by arranging the urging member between the meshing members, it is not necessary to consider a space for the urging member, and the chemical injector is not enlarged.
[0066]
  Claim5According to the invention, claims 1 to4In addition to the effect of the invention of any one of the above, the pressing device can be used effectively by being used for the pressing of the plunger of the syringe that is pressed for the injection of the chemical solution.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing a chemical injector in the present embodiment.
FIG. 2 is an enlarged view of a main part showing a pusher.
FIGS. 3A and 3B are enlarged views of main parts showing a slide nut.
FIG. 4 is an enlarged cross-sectional view of a main part showing a slide nut and a slide block.
FIG. 5 is a side sectional view showing a conventional chemical liquid injector.
FIG. 6 is an enlarged view of a main part showing the half nut.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 13 ... Feed screw, 13a ... Screw surface, 16 ... Slide block (slide mechanism), 19 ... Slide nut (conversion means), 21 ... Slide cylinder (slide mechanism), 23 ... Pusher (slide mechanism), 27 ... Connecting shaft ( Opening / closing operation mechanism), 28 ... Cam (opening / closing operation mechanism), 31 ... Syringe, 33 ... Plunger (member to be pressed), 41 ... First half nut (meshing member), 42 ... Tension spring (biasing member), 43 ... Thread surface, 44... Cam driven surface (end portion on the anti-screw surface side), 51... Second half nut (meshing member), 53.

Claims (5)

A feed screw that is rotated by driving of the drive means; a conversion means that converts rotation of the feed screw into linear motion; an open / close operation mechanism that operates the conversion means; and the feed screw that is linked to the linear motion of the conversion means. And a slide mechanism that is movable along the longitudinal direction, and a pressing device that presses the pressed member by movement of the slide mechanism,
The converting means has a thread surface corresponding to the thread surface of the feed screw, and a pair of meshing members that mesh with the feed screw so as to be disengageable from both sides, and bias the meshing members in a direction facing each other. a biasing member for,
The opening / closing operation mechanism includes a cam that engages and disengages the meshing member with respect to the feed screw, a connection shaft that is a rotation center of the cam, and an operation lever that rotates the connection shaft.
The slide mechanism is integrated with the conversion means and is slidably provided on the feed screw, a pusher that presses the pressed member, and a slide cylinder that connects the slide block and the pusher. And
The connecting shaft is inserted into the slide cylinder,
The pressing device , wherein the operating lever is attached to the pusher . The screw surfaces of the respective meshing members are respectively formed corresponding to the half circumferences of the opposing feed screws, and when both the mesh members mesh the feed screws, the both screw surfaces extend over the entire outer periphery of the feed screw. pressing of claim 1, wherein the meshing. The said both meshing member is axially attached so that it may mutually cross | intersect in the middle, The said cam is arrange | positioned between the counter screw surface side edge parts of a meshing member, The Claim 1 or Claim 2 characterized by the above-mentioned. Presser. The pressing device according to any one of claims 1 to 3, wherein the urging member is disposed between both the meshing members . Wherein the pressing member, the pressing device as claimed in any one of the plunger der Ru claims 1 to 4 of the syringe that is pressed for liquid injection.

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