JPH0986859A - Test tube carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate fixed holding power without recourse to the diameter of a test tube, in a test tube carrier which catches up a test tube by a pair of fingers. SOLUTION: The revolution of a motor 12 is converted into linear motion by a rectilinear conversion mechanism 100, and further it is converted into the opening/closing motion of the a pair of fingers 50 by an opening and closing conversion mechanism 102. From the point of time when a test tube is nipped between a pair of fingers 50, a spring 44 begins to compress, and the point of time when fixed holding power is accumulated in a spring 44 is detected by MS2. Hereby, the rotation of the motor 12 stops. The mechanical stress by overrun is absorbed by the spring 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test tube carrier, and more particularly to a mechanism for picking up a test tube by a pair of fingers.

[0002]

2. Description of the Related Art A pair of fingers provided in a test tube transporting device is opened and closed by a driving device, and the upper part of the test tube is picked up by the pair of fingers to transport the test tube. As a driving method for the pair of fingers, an air cylinder driving method using air pressure and a method using an electromagnetic solenoid are known.

[0003]

The above air cylinder drive system can generate a relatively large force,
Moreover, since a constant gripping force can be generated irrespective of the diameter of the test tube, that is, irrespective of the stroke, it is widely used in various test tube transport devices.

However, there is a problem that it is difficult to miniaturize the apparatus because it requires additional equipment such as a compressor for generating air, an air clean unit for removing water and the like, and a pressure control device.

On the other hand, the above-mentioned electromagnetic solenoid drive system opens and closes a pair of fingers by turning the power supply on and off, and can be relatively downsized, but the gripping force varies depending on the diameter of the test tube and the like. There is a problem that it will end up.
In other words, since the gripping force changes according to the relative distance between the solenoid and the movable piece (armature) attracted to it, the gripping force varies depending on whether the diameter of the test tube is large or small, and the gripping force is changed. It is difficult to keep constant, for example, when the test tube is labeled,
There is a problem that the grip strength fluctuates.

The present invention has been made in view of the above conventional problems, and an object thereof is to provide a lightweight test tube transporting device capable of generating a constant gripping force regardless of the diameter of the test tube. The purpose is to

It is another object of the present invention to provide a test tube carrying device capable of accumulating and holding an appropriate gripping force of a pair of fingers.

Another object of the present invention is to automatically detect an abnormal state such as when a test tube does not exist, when it fails to grab, or when jamming occurs.

Another object of the present invention is to provide an overrun when the pair of fingers are opened.
The purpose of this is to absorb the mechanical strain caused thereby and to ensure a reliable operation.

[0010]

In order to achieve the above object, the present invention provides a pair of open / close fingers for grasping a test tube, a motor for generating a rotational force, and a rotational movement by the motor. It is composed of a conversion mechanism for converting the finger into an opening / closing motion and an elastic deformation member connected to the conversion mechanism. Elastic deformation occurs from the time when the test tube is sandwiched between the pair of fingers, and the rotational force of the motor is changed. The gripping force accumulating means for accumulating, the proper gripping force detecting means for detecting an appropriate gripping force, and the appropriate gripping force are detected when a certain elastic force is accumulated in the gripping force accumulating means. And a control unit for stopping the normal rotation operation of the motor at a time point.

According to the above construction, the motor generates the rotational force, and the rotational movement is converted into the opening / closing movement of the pair of fingers by the conversion mechanism. In that case, after the test tube is sandwiched by the pair of fingers, the rotational force of the motor is accumulated in the grasping force accumulating means until the proper grasping force is detected. Then, the rotation of the motor is stopped when the proper gripping force is obtained, and thereafter, the elastic force accumulated in the gripping force accumulating means is continuously transmitted to the pair of fingers, and the test is performed with a constant gripping force. The tube is retained.

Therefore, since the motor is used, the device can be made relatively small, and the motor is rotated until the proper gripping force is obtained, and then the proper gripping force is maintained even if the motor is stopped. Therefore, the driving force of the motor can be efficiently used. According to the present invention, the gripping force itself is detected, and the gripping force can be maintained from the time when it reaches an appropriate value, so that the gripping force does not fluctuate according to the diameter of the test tube. It is possible to maintain

In a preferred aspect of the present invention, the conversion mechanism includes a linear conversion mechanism for converting rotational movement by the motor into linear movement, and an opening / closing conversion mechanism for converting the linear movement into opening / closing movement of the pair of fingers. ,including.

Further, in a preferred aspect of the present invention, the gripping force accumulating means is composed of a first spring which starts elastic deformation from the time when the test tube is sandwiched by the pair of fingers. That is, gripping force is accumulated as compression deformation or extension deformation of the spring. Further, in a preferred aspect of the present invention, the linear conversion means includes a screw rotated by the rotational movement of the motor, and a nut body screwed with the screw and vertically moved by the rotation of the screw.

Also, in a preferred aspect of the present invention, the opening / closing switching means is connected to the nut body via the first spring, and a connecting body to which vertical movement of the nut body is transmitted, An arm mechanism for converting the vertical movement of the connecting body into the opening / closing movement of the finger, and after the test tube is sandwiched between the pair of fingers to prevent the movement of the connecting body, The first by exercise
The spring is elastically deformed.

Further, in a preferred aspect of the present invention, a second spring for absorbing an overrun of the opening operation of the pair of fingers is included.

Further, in a preferred aspect of the present invention, it has an open state detecting means for detecting an open state of the pair of fingers.

Further, in a preferred aspect of the present invention, there is a closed state detecting means for detecting the closed state of the pair of fingers when the test tube is not present.

Further, in a preferred aspect of the present invention, there is provided jamming detection means for detecting a thrusting action on the pair of fingers due to jamming.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the construction of a gripping unit of a test tube carrier according to the present invention. This test tube transporting device is incorporated in, for example, various chemical analysis devices, dispensing devices, and the like.

In FIG. 1, the upper portion of the chassis 10 is bent in the horizontal direction, and the motor 12 is fixedly arranged on the upper portion of the chassis 10. This motor 12
Is controlled by a control unit (not shown), and a so-called DC motor is used in this embodiment. The motor shaft 12A of the motor 12 is directed downward, and the screw 16 is inserted through the coupling portion 14.
It is connected to. The coupling unit 14 is the motor shaft 1
2A, a pin 18 fixedly inserted through the pin 18 and a coupling member 20 engaging with the pin, and a well for receiving the motor shaft 12A is formed in an upper portion of the coupling member 20. Two flutes 20A for receiving 18 are formed. That is, when the motor shaft 12A rotates, the pin 18 rotates accordingly, and the vertical groove 20A
The rotational force is transmitted to the coupling member 20, which causes the coupling member 20 to rotate. In the present embodiment, as shown in FIG. 1, a certain degree of freedom is provided in the vertical direction at the position of the pin 18 in the vertical groove 20A, and the vertical movement of the coupling member 20, that is, the screw 16 is slightly permitted. ing.

The screw 16 is connected and fixed to the lower side of the coupling member 20, and when the coupling member 20 rotates, the screw 16 rotates. The screw 16 is held by a bearing 22, and the screw 16 is rotatably held by a bearing mechanism provided inside the bearing 22. A thrust bearing 24 and a spring 26 are interposed between the bearing 22 and the coupling member 20. Here, the spring 26 urges the screw 16 upward with respect to the bearing 22.
The operation of 6 will be described later in detail.

Rails 28 are formed on the chassis 10 along the vertical direction. The sliding member 30 connected to the bearing 22 straddles and engages with the rail 28.
That is, the bearing 22 is slidable in the vertical direction along the rail 28. However, a stopper 32 that sets the lower end of the bearing 22 is fixedly arranged on the chassis 10, and the stopper 32 restricts the downward movement of the sliding member 30.

A screw portion is formed on the screw 16, and the screw portion is engaged (screwed) with the nut body 34. That is, the nut body 34 is formed with a screw portion that meshes with the screw portion of the screw 16, while the sliding member 35 connected to the nut body 34 is engaged across the rail 28. When the screw 16 rotates, the rotation causes the nut body 34 to move up and down along the rail 28. That is, the linear conversion mechanism 100 is configured by the screw 16 and the nut body 34, and the motor 1
The rotary motion of 2 has been converted into a linear motion. Nut body 3
A lock nut 36 is provided at a lower portion of the lock block 4, and a hook portion 38 </ b> A of a connecting block 38 is placed on the lock nut 36. That is, the connection block 38 hangs from the lock nut 36. The sliding member 40 provided on the connecting block 38 is engaged across the rail 28, that is, the connecting block 38 is only allowed to move up and down. The stopper 42 hits the sliding member 40 and sets the upper end of the connecting block 38.

As shown in FIG. 1, a spring 44 is interposed between the hook portion 38A and the jaw portion 34A of the nut body 34 in a compressed state. The spring 44 is a spring for accumulating a proper gripping force as described later, and its action will be described in detail later. A support shaft 46 is provided at the lower end of the connection block 38, and two arms 48 are connected to the support shaft 46. The working end of each arm 48 is rotatably connected to the upper end of the finger 50. Therefore, when the connecting block 38 moves downward, the support shaft 46 moves accordingly, and on the other hand, the upper end of the finger 50 is prevented from moving downward by the fixed shaft 52. The downward movement is converted by the two arms 48 into a closing movement of the fingers 50. That is, the connection block 3 described above.
8, the support shaft 46, the two arms 48, and the fixed shaft 52 constitute the opening / closing conversion mechanism 102, and the linear motion is converted into the opening / closing motion. The pair of fingers 50 has a rubber material 54 inside the lower end portions thereof, and grips and grips the upper portion of the test tube.

The MS (micro switch) 1 is fixedly arranged on the main body of the apparatus, and has a rising end of the nut body 34.
That is, the open state of the finger 50 is detected, and specifically, the operating piece 5 fixedly arranged on the nut body 34 is used.
When the shaft of MS1 is brought into contact with 6, the rising end is detected. The MS 2 has a spring 4 as described later.
4 is for elastically compressing and detecting a state in which an appropriate gripping force is accumulated therein. Specifically, in such a state, the distance between the nut body 34 and the connecting block 38 is narrowed, The state is detected by the operating piece 58 coming into contact with the shaft of the MS 2. MS2 is connected block 3
8 is fixedly arranged.

The MS 3 is fixedly arranged on the main body of the apparatus, and detects the operating piece 60 provided on the connecting block 38 when the operating piece 60 descends downward by a certain distance. That is, when the test tube does not exist between the pair of fingers 50 and the finger 50 makes a closing motion, the connecting block 38 moves downward more than the normal gripping motion, so that motion is detected. As a result, the absence of the test tube is detected.

The MS 4 is a switch for detecting so-called jamming, and when the tip of the finger 50 hits the upper part of the test tube and an upward thrusting force is generated in the entire unit shown in FIG. 1, that is, The movement of the chassis 10 is detected when upward pushing force is generated. The MS 4 is fixed to the main body of the device.

Next, the operation of the spring 44 will be described in detail. When the motor 12 rotates in the normal direction and the screw 16 rotates in the normal direction via the coupling portion 14, the nut body 34 moves downward. This movement is transmitted as a downward movement of the connecting block 38, and the movement is converted into a closing movement of the finger 50. Here, when the test tube is sandwiched between the pair of fingers 50, the closing movement of the pair of fingers 50 is stopped, that is, the downward movement of the connecting block 38 is stopped. When the normal rotation of the motor 12 is further continued in this state, the nut body 34 continues to move downward accordingly. That is, the distance between the nut body 34 and the hook portion 38A of the connecting block 38 is reduced, and the spring 44 is compressed and deformed. The elastic force of the spring 44 corresponds to the gripping force of the pair of fingers 50, that is, the gripping force of the finger 50 is accumulated as the elastic deformation of the spring 44. A certain elastic force is accumulated in the spring 44, that is, the nut body 3
When the distance between the connection block 4 and the connection block 38 reaches a certain distance, the state in which the MS2 comes into contact with the operating piece 58 to generate the proper gripping force is detected, and the detection signal indicates that the gripping force is generated. The control unit which does not exist stops the forward rotation of the motor 12. Here, even after the rotation of the motor 12 is stopped, the spring 44 exerts an elastic force on the pair of fingers 50, which is maintained until the motor 12 starts the reverse movement. As is clear from the above description, since the spring 44 undergoes elastic deformation from the time when the pair of fingers 50 abut on the test tube, a constant gripping force is generated regardless of the diameter of the test tube. At that time, the rotation of the motor 12 can be stopped.

Next, the operation of the spring 26 will be described. As described above, when the motor 12 is rotated in the reverse direction from the state in which the test tube is picked up by the pair of fingers 50, the nut body 34 is gradually pulled up with the reverse rotation of the screw 16, and is compressed accordingly. The spring 44 gradually expands, and the finger 50 starts the opening operation when the hook portion 38A comes into contact with the lock nut 36. Then, when the nut body 34 reaches the rising end, the operating piece 56 is hit by the MS1, and the reverse rotation of the motor 12 is stopped under the control of the control unit. Here, when the stop of the motor 12 is delayed and so-called overrun occurs, the sliding member 40 hits the stopper 42, whereby the upward movement of the coupling block 38 and the nut body 34 is forcibly prevented. , Nevertheless screw 1
When 6 rotates in the reverse direction, the reverse rotation of the screw 16 is converted into the action of pulling the screw 16 itself downward. In this embodiment, the excessive driving action due to such overrun is absorbed and removed as the compression of the spring 26. That is, when the screw 16 is pulled downward with respect to the bearing 22, the spring 26 is elastically compressed and the mechanical strain is absorbed as the compression of the spring 26. If such a spring 26 does not exist, mechanical distortion will occur in any of the members, which will reduce the reliability of the device.
According to this embodiment, such a problem is solved. Of course, since the motor 12 and the coupling portion 14 are connected only for rotational movement, and the vertical movement of the coupling portion 14 is given a certain degree of freedom, mechanical distortion is not generated between them. Absent. When the spring 26 is elastically compressed and the next test tube is to be picked up, the spring 26 extends in accordance with the normal rotation of the motor 12 and returns to the original state. The closing movement is performed.

As is apparent from the above description, the load of each member is applied to the spring 26. Therefore, the spring 26 has a force equal to or greater than the biasing force for pulling the screw 16 upward against the load. It is set below the elastic force that can absorb the overrun. Further, as the spring 44, a spring having a spring force equivalent to an appropriate gripping force when it is compressed to some extent is used.

FIG. 2 shows the basic control of the control unit. As shown in FIG. 2, when the motor starts to rotate and the gripping operation is started, and the nut body 34 is pulled down, MS1 is turned off. After that, when the spring 44 undergoes a predetermined elastic deformation, MS2 is released. It is turned on, and as a result, the normal rotation of the motor is stopped.

On the other hand, when the test tube is released from the gripped state, the motor is reversed. Along with this, first, MS2 is switched from ON to OFF, and when the motor 12 is subsequently rotated in the reverse direction, MS1 is turned ON, and at that time, the control unit stops the reverse rotation of the motor. The overrun generated at this time is absorbed and removed by the action of the spring 26 as described above, and the finger 50 can always be opened to a constant state. The maximum opening amount of the pair of fingers 50 can be set by the position of the stopper 42 in contact with the sliding member 40.

FIG. 3 shows the reset operation of the test tube carrier. This routine starts after the transport unit shown in FIG. 1 is pulled upward with respect to the apparatus main body. In S101, the state of MS2 is read, and if MS2 is on, an alarm is generated in S102 and the operator is asked to confirm the operating state.

In S103, the motor 12 is rotated in the reverse direction.
Then, in S104, the state of MS1 is read, and if it is off, the reverse rotation of the motor is continued. Meanwhile, MS
If 1 is turned on, the reverse rotation of the motor is stopped in S105.

By the resetting operation as described above, the nut body 34 is pulled up to the rising end, and the gripping operation of the test tube, which will be described next, is continuously performed.

FIG. 4 shows the operation of gripping the test tube. First, in S201, the state of MS2 is read, and if it is on, an alarm is generated in S202 and the operator is asked to confirm the operating state.

Next, in S203, the entire unit shown in FIG. 1 located above the test tube to be picked up is lowered. At this time, the occurrence of so-called jamming is monitored in S203. When jamming is detected by the MS 4, the downward descent operation performed in S203 is stopped and an alarm or the like is generated.

In S204, the motor 12 is rotated in the forward direction to start the closing movement of the finger 50. And
When the state of MS2 is read in S205 and it is determined that the proper gripping force is not yet accumulated in the spring 44, that is, when MS2 is off, the state of MS3 is subsequently read and it is turned off. If it is in the state, the normal rotation operation of the motor in S204 is continued as it is. Here, in S206, when MS3 is turned on although MS2 is turned off, it is expected that no test tube is present between the pair of fingers 50.
In S207, the rotation of the motor 12 is stopped, and S20
In 8, the display indicates that there is no test tube.

On the other hand, if it is determined in S205 that the MS2 is in the ON state, that is, the spring 44
Is determined to have been properly compressed and an appropriate gripping force has been accumulated therein, the forward rotation operation of the motor is stopped in S209, and the grasp completion is displayed on the display in S210. After that, the test tube is grasped in S211 as shown in FIG.
Raise the entire unit shown in (1) upward. In this case, S
If it is determined that the MS2 is turned on in 212, that is, if the MS2 is turned on once and then turned off, the test tube is expected to drop or fail to be grasped. Raise an error. On the other hand, if the state of MS2 is maintained, S2
At 14, the whole unit shown in FIG. 1 is horizontally moved in the XY directions to carry the test tube to a predetermined position. Note that S
At 212, the state of the MS 3 may be detected, and if it is turned on, it may fail to catch and cause an error.

FIG. 5 shows the releasing operation of the test tube. In S301, the state of MS2 is read and MS2
If is off, it is expected that the test tube will fall during transportation, so an alarm is generated in S302 and the operator is asked to confirm the operation. In S303, the entire unit shown in FIG. 1 is lowered. Then, in S304, the motor 12 is rotated in the reverse direction. In this case, in S305, MS1
Is read and while the MS1 is in the off state,
The motor reverse rotation in S304 is continued. On the other hand, if it is determined in S305 that the MS1 is turned on, that is, if it is determined that the nut body 34 is located at the upper end, the reverse rotation operation of the motor 12 is stopped in S306.

Then, in S307, the state of the MS2 is read, and if it is determined that the MS2 is on, some trouble is expected, so an alarm is generated in S308. On the other hand, when it is determined in S307 that the MS2 is off, it is determined that the normal test tube release operation is completed, and this routine is ended.

In the embodiment shown in FIG. 1, the nut body 34
Although the spring 44 in which an appropriate gripping force is accumulated is arranged between the connection block 38 and the connection block 38, a spring having such a function can be arranged in another position. In any case, the same action and effect as described above can be obtained by using the spring force to maintain the gripping force of the pair of fingers 50.

The location of each microswitch shown in FIG. 1 is an example, and it can be placed at another location as long as its function is achieved.

According to the above embodiment, for example, the weight of the entire unit can be halved as compared with the case where an electromagnetic solenoid that generates a similar gripping force is used. Therefore, there is an advantage that the size and weight can be reduced as compared with the air cylinder drive system and the electromagnetic solenoid drive system. Regarding the operating speed, it is slightly inferior when compared to each conventional method, but if there is a sample in the test tube, if you accidentally pick up the test tube at a high speed, The sample may be scattered from the inside due to the impact, and the device of the present embodiment can obtain a sufficient operation speed within a range where such a problem does not occur.

When a plurality of test tubes are conveyed at the same time, a plurality of units shown in FIG. 1 may be provided in parallel and the control section may collectively control them.

[0048]

As described above, according to the present invention, it is possible to provide a lightweight test tube transporting device capable of generating a constant gripping force regardless of the diameter of the test tube. Further, according to the present invention, the proper gripping force of the pair of fingers can be mechanically accumulated and held. Furthermore, according to the present invention, when there is no test tube, when it fails to grab, when jamming occurs, it is possible to automatically detect an abnormal state,
Further, it is possible to absorb the mechanical strain generated when an overrun occurs in the opening operation of the pair of fingers.

[Brief description of drawings]

FIG. 1 is a diagram showing a carrying unit of a test tube carrying device according to the present invention.

FIG. 2 is a timing chart showing the operation of the test tube transport device according to the present invention.

FIG. 3 is a flowchart showing a resetting operation of the test tube transport device according to the present invention.

FIG. 4 is a flowchart showing a gripping operation of the test tube transport device according to the present invention.

FIG. 5 is a flowchart showing a releasing operation of the test tube transport device according to the present invention.

[Explanation of symbols]

12 motor, 14 coupling part, 16 screw, 26 spring, 34 nut body, 38 connecting block, 44 spring, 50 finger, 100
Linear conversion mechanism, 102 Open / close conversion mechanism.

Claims (9)

[Claims] 1. A pair of openable and closable fingers for grasping a test tube, a motor for generating a rotational force, a conversion mechanism for converting a rotational movement of the motor into an opening and closing movement of the pair of fingers, and a connection to the conversion mechanism. And a gripping force accumulating means for accumulating the rotational force of the motor and elastically deforming when the test tube is sandwiched between the pair of fingers. An appropriate gripping force detection means for detecting an appropriate gripping force when a certain elastic force is accumulated, and a control unit for stopping the forward rotation operation of the motor at the time when the appropriate gripping force is detected. A test tube transporting device comprising: 2. The apparatus according to claim 1, wherein the conversion mechanism is a linear conversion mechanism that converts a rotational motion of the motor into a linear motion, and an open / close conversion that converts the linear motion into an opening / closing motion of the pair of fingers. A test tube transfer device comprising: a mechanism. 3. The apparatus according to claim 2, wherein the gripping force accumulating means is a first spring that starts elastically deforming when the test tube is sandwiched by the pair of fingers. Test tube carrier. 4. The apparatus according to claim 3, wherein the linear conversion mechanism includes a screw rotated by the rotational movement of the motor, and a nut body screwed with the screw and vertically moved by the rotation of the screw. A test tube transport device characterized in that 5. The device according to claim 4, wherein the opening / closing switching means is connected to the nut body via the first spring, and a vertical movement of the nut body is transmitted to the nut body. An arm mechanism for converting the vertical movement of the connecting body into the opening / closing movement of the finger, and, after the test tube is sandwiched by the pair of fingers to prevent the movement of the connecting body, A test tube transporting device, wherein the first spring is elastically deformed by movement. 6. The test tube transport device according to claim 1, further comprising a second spring that absorbs an overrun of the opening operation of the pair of fingers. 7. The test tube transport device according to claim 1, further comprising an open state detection unit that detects an open state of the pair of fingers. 8. The test tube transporting device according to claim 1, further comprising a closed state detection unit that detects a closed state of the pair of fingers when the test tube does not exist. 9. The test tube transporting device according to claim 1, further comprising a jamming detection unit that detects a push-up action on the pair of fingers due to jamming.