Patent Description:
A dispensing mechanism of a reagent or a specimen in an automatic analyzer is formed by a probe for sucking and discharging the reagent and the like, an arm for supporting the probe, and a driving mechanism for driving the arm. The probe vertically moves to each stopping position as well as horizontally moves to a suction position and a discharge position of the reagent and the like and a cleaning position where to clean the probe. With a higher-level function of the automatic analyzer, for example, like Patent Literature <NUM>, there has been provided with a dispensing mechanism having a rotational degree of freedom along two axes with respect to a horizontal movement, what is called, a structure of two-link arm.

Here, the conventional dispensing mechanism having two degrees of freedom will be described. <FIG> is a perspective view showing a state (a) before an arm is lowered and a state (b) after the arm is lowered. In the conventional dispensing mechanism of the two-link arm, a motor <NUM> is used to rotate a first shaft <NUM>, thereby driving an inside arm <NUM>, and a motor <NUM> is used to rotate a second shaft <NUM>, thereby driving an outside arm <NUM>. When lowering the arm, the first shaft <NUM> is lowered while rotating a rotary ball spline, and also the second shaft <NUM> is lowered while rotating a ball spline <NUM>.

In the above conventional two link arm, however, when the arm is vertically moved, the whole second shaft is lowered and protrudes from the lower part of the base of the dispensing mechanism by the amount of descent. Therefore, a space is required below the base to avoid the protruding shaft, and the layout of the unit to be arranged below the dispensing mechanism is restricted. Alternatively, it would be necessary to shift the position of the dispensing mechanism to allow the shaft to protrude.

Other conventional analyzer mechanisms are described in <CIT> and <CIT>. The invention aims to provide an automatic analyzer improved in the degree of freedom with respect to the arrangement of the dispensing mechanism and the unit provided below the above mechanism.

In order to achieve the above object, the invention provides an automatic analyzer as defined in appended claim <NUM>.

According to the invention, it is possible to provide an automatic analyzer improved in the degree of freedom with respect to the arrangement of a dispensing mechanism and a unit provided below the above, by avoiding a part of a shaft from protruding from the lower part of the dispensing mechanism or by decreasing the protruding amount.

<FIG> is a perspective view showing an entire configuration of an automatic analyzer according to an embodiment. The automatic analyzer is a device in which a sample (specimen) and a reagent are dispensed in a plurality of reaction containers <NUM> to react with each other and the reacted liquid is measured. The automatic analyzer includes a reaction disk <NUM>, a reagent disk <NUM>, a specimen transport mechanism <NUM>, reagent dispensing mechanisms <NUM> and <NUM>, a syringe for reagent <NUM>, specimen dispensing mechanisms <NUM> and <NUM>, a syringe for specimen <NUM>, a cleaning mechanism <NUM>, a light source 4a, a spectrophotometer <NUM>, stirring mechanisms <NUM> and <NUM>, a pump for cleaning <NUM>, cleaning tanks <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, and a controller <NUM>.

Reaction containers <NUM> are aligned on the circumference of the reaction disk <NUM>. The specimen transport mechanism <NUM> for transferring a specimen rack <NUM> with specimen containers (test tubes) <NUM> mounted thereon is arranged in the vicinity of the reaction disk <NUM>. The specimen container <NUM> contains an inspection specimen such as blood and the like, which is mounted on the specimen rack <NUM> and carried by the specimen transport mechanism <NUM>. The rotatable and vertically movable specimen dispensing mechanisms <NUM> and <NUM> are arranged between the reaction disk <NUM> and the specimen transport mechanism <NUM>. The specimen dispensing mechanisms <NUM> and <NUM> have the respective specimen probes 11a and 12a with the syringes for specimen <NUM> and 19a connected, and the specimen probes 11a and 12a move along arc track around the rotation axes of the specimen dispensing mechanisms <NUM> and <NUM>, to dispense the specimens from the specimen containers <NUM> to the reaction containers <NUM>.

The reagent disk <NUM> can mount a plurality of reagent bottles <NUM> on its circumference. The reagent disk <NUM> is kept cool. Rotatable and vertically-movable reagent dispensing mechanisms <NUM> and <NUM> are arranged between the reaction disk <NUM> and the reagent disk <NUM>. The reagent dispensing mechanisms <NUM> and <NUM> have the respective reagent probes 7a and 8a with the syringes for reagent <NUM> and 18a connected, and the reagent probes 7a and 8a move along arc around the rotation axes, get access to the reagent disk <NUM>, and dispense the reagent from the reagent bottle <NUM> to the reaction container <NUM>.

Around the reaction disk <NUM>, there are arranged a cleaning mechanism <NUM> for cleaning the reaction container having been measured, stirring mechanisms <NUM> and <NUM> for stirring a mixed liquid (reaction liquid) of a reagent and a specimen within the reaction container, a light source 4a and a spectrophotometer <NUM> for irradiating the mixed liquid (reaction liquid) within the reaction container with light and measuring, for example, its absorbance. Further, a pump for cleaning <NUM> is connected to the cleaning mechanism <NUM>. Cleaning tanks <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are respectively provide in the range of the movement of the specimen dispensing mechanisms <NUM> and <NUM>, the reagent dispensing mechanisms <NUM> and <NUM>, and the stirring mechanisms <NUM> and <NUM>. Each mechanism of the automatic analyzer is connected to the controller <NUM> and controlled.

Analysis processing of an inspection specimen by the automatic analyzer is generally executed according to the following steps. At first, a specimen within the specimen container <NUM> mounted on the specimen rack <NUM> which is carried near the reaction disk <NUM> by the specimen transport mechanism <NUM> is dispensed to the reaction container <NUM> on the reaction disk <NUM> according to the specimen probe 11a of the specimen dispensing mechanism <NUM>. Next, a reagent to be used for analysis is dispensed from the reagent bottle <NUM> on the reagent disk <NUM> to the reaction container <NUM> in which the sample has been previously dispensed, according to the reagent probe 7a of the reagent dispensing mechanism <NUM> or the reagent probe 8a of the reagent dispensing mechanism <NUM>. Continuously, the stirring mechanism <NUM> stirs the mixed liquid of the specimen and the reagent within the reaction container <NUM>.

Then, the light generated from the light source 4a is transmitted through the reaction container <NUM> containing the mixed liquid, and the light intensity of the transmitted light is measured by the spectrophotometer <NUM>. The light intensity measured by the spectrophotometer <NUM> is sent to the controller <NUM> through an A/D converter and an interface. The controller <NUM> calculates, for example, the concentration and the like of a predetermined component of the analysis item according to the reagent from the absorbance of the mixed liquid (reaction liquid). The obtained measurement results are displayed on a display unit (not shown) or the like. Although the explanation will be made by way of example of an automatic analyzer using the spectrophotometer <NUM> to require the concentration of a predetermined component, the technology disclosed in the embodiment described below may be used for an automatic immunological analyzer or an automatic coagulation analyzer that measures a sample using another photometer.

<FIG> is a perspective view wherein, regarding the dispensing mechanism according to the embodiment, an arm and a base <NUM> are omitted. As shown in <FIG>, the dispensing mechanism according to the embodiment has a first shaft <NUM> and a second shaft, as a shaft transmitting power to an arm while supporting the arm. The first shaft <NUM> is a rotation axis for rotating a first arm and the second shaft is a rotation axis for rotating a second arm. As described later, the second shaft is divided into an upper shaft <NUM> and a lower shaft <NUM> in an axial direction and they have different diameters.

At first, a structure for rotating the first arm through the first shaft <NUM> will be described.

To rotate the first arm, the power of the motor <NUM> is used. A pulley on the driving side built in the motor <NUM> is connected to a pulley <NUM> on the driven side through a belt <NUM>, and the pulley <NUM> is further fixed to a rotary ball spline <NUM> (a sleeve portion <NUM> in <FIG>). The rotary ball spline <NUM> as a ball spline for the first shaft slidably supports the first shaft <NUM> as a spline shaft and can transmit the torque of the pulley <NUM> to the first shaft <NUM>. Therefore, the rotational power of the motor <NUM> is transmitted to the first shaft <NUM> through the belt <NUM>, the pulley <NUM>, and the rotary ball spline <NUM>. When the arm moves vertically, the first shaft <NUM> slides onto the pulley <NUM> and the rotary ball spline <NUM>, which enables the vertical movement of the first shaft <NUM>. The pulley <NUM> on the driven side is reduced in speed by enlarging its diameter more than that of the pulley on the driving side, hence to be able to reduce the load due to the inertia at the rotation time of the first arm.

Next, a structure for rotating the second arm through the second shaft will be described.

To rotate the second arm, the power of the motor <NUM> is used. A pully on the driving side built in the motor <NUM> is connected to a pulley <NUM> on the driven side through a belt <NUM> and further the pulley <NUM> is fixed to the lower end of the lower shaft <NUM>. The lower shaft <NUM> as the spline shaft is slidably supported by a ball spline <NUM> as a ball spline for the lower shaft. Here, the ball spline <NUM> is fixed to a joint <NUM>, and further the joint <NUM> is fixed to the upper shaft <NUM> (refer to <FIG>). Therefore, the rotation power of the motor <NUM> is transmitted to the upper shaft <NUM> through the belt <NUM>, the pulley <NUM>, and the lower shaft <NUM>. Further, the pulley <NUM> on the driven side is reduced in speed by enlarging its diameter more than that of the pulley on the driving side, hence to be able to reduce the load due to the inertia at the rotation time of the second arm.

Next, a structure for vertically moving the first arm and the second arm through the shaft will be described.

To move each arm vertically, the power of the motor <NUM> is used. A belt <NUM> for vertical movement is endlessly wound around a pully on the driving side built in the motor <NUM> and a pulley <NUM> on the driven side. A joint <NUM> is fixed to the belt <NUM> connecting these two pulleys on the side of the same moving direction as the first shaft <NUM>, and a balance weight <NUM> is fixed on the side of the moving direction opposite to the moving direction of the first shaft <NUM>. The joint <NUM> is formed integrally with the slider <NUM>. The balance weight <NUM> is to reduce the torque of the motor <NUM> required to drive the belt <NUM>. When the joint <NUM> vertically moves according as the belt <NUM> is driven, the shaft (the lower shaft <NUM>) works as a rail through the slider <NUM>, which makes the joint <NUM> and the slider <NUM> smoothly move up and down. At this time, since the balance weight <NUM> moves vertically along a rail <NUM>, the balance weight <NUM> can be moved up and down smoothly. When the joint <NUM>, the slider <NUM>, the first shaft <NUM>, and the second shaft (the upper shaft <NUM>) move up, the balance weight <NUM> gets down, while the joint <NUM> and the like get down, the balance weight <NUM> moves up.

Further, the slider <NUM> incorporates the bearing and restricts the position of the upper shaft <NUM> in the axial direction as for the first shaft <NUM>, while rotatably supporting the first shaft <NUM> and the upper shaft <NUM>. Therefore, when the motor <NUM> is driven, the first shaft <NUM> and the upper shaft <NUM> vertically move through the slider <NUM>.

<FIG> is a front view of a dispensing mechanism according to the first embodiment and <FIG> is a sectional view of the dispensing mechanism according to the first embodiment. The dispensing mechanism according to the first embodiment includes an outside arm <NUM> as a second arm for supporting each of the reagent probes 7a and 8a and an inside arm <NUM> as a first arm connected to this outside arm <NUM>, in a structure of <NUM>-link arm capable of two-degree-of-freedom positioning. Although in this embodiment, the dispensing mechanism including each of the reagent probes 7a and 8a will be described, it is needless to say that it can be adopted to the dispensing mechanism including a specimen probe.

The dispensing mechanism according to the embodiment includes the inside arm <NUM> and the outside arm <NUM>, further the base <NUM>, the first shaft <NUM>, the second shaft, the motor <NUM> for rotating the first shaft <NUM>, the motor <NUM> for rotating the second shaft, and the motor <NUM> for vertically moving the first shaft <NUM> and the second shaft (the upper shaft <NUM>). Then, the motor <NUM>, the motor <NUM>, and the motor <NUM> are fixed to the base <NUM>.

As shown in <FIG>, a pulley <NUM> within the inside arm <NUM> is attached to the upper end of the upper shaft <NUM> forming the second shaft. This pulley <NUM> rotates a pulley <NUM> through a belt <NUM> and a shaft <NUM> fixed to the pulley <NUM>. This shaft <NUM> is joined to the outside arm <NUM>. When the upper shaft <NUM> rotates, the outside arm <NUM> rotates with the distal end of the inside arm <NUM> as a rotation axis and each of the reagent probes 7a and 8a at the distal end of the outside arm <NUM> is positioned. Since the upper end of the first shaft <NUM> is connected to the inside arm <NUM>, when the first shaft <NUM> rotates, the inside arm <NUM> is rotated.

In the embodiment, there are provided with the rotary ball spline <NUM> that supports the first shaft <NUM> slidably in a vertical direction regarding the base <NUM> and the ball spline <NUM> that supports the lower shaft <NUM> slidably in a vertical direction regarding the upper shaft <NUM>. Here, the rotary ball spline <NUM> includes a cylindrical sleeve portion <NUM> fitted externally to the first shaft <NUM> as the spline shaft and a flange portion <NUM> arranged on the outer peripheral side of this sleeve portion <NUM> via the rotary bearing. Then, the upper side of the sleeve portion <NUM> is fixed to the pulley <NUM>. Further, the flange portion <NUM> is used to fix the rotary ball spline <NUM> to a through-hole provided on the top of the base <NUM>.

The outer diameter of the lower shaft <NUM> having a solid cross section horizontally is smaller than the internal diameter of the upper shaft <NUM> having a hollow cross section horizontally, so that the lower shaft <NUM> can be housed into the upper shaft <NUM> concentrically. When the arm operates downwardly, the lower shaft <NUM> does not move in an axial direction but the upper shaft <NUM> is lowered. Here, in the embodiment, since a bush <NUM> is arranged in the upper end of the lower shaft <NUM>, a contact portion of the lower shaft <NUM> and the upper shaft <NUM> is restricted to the bush <NUM> and the ball spline <NUM>. Therefore, when the arm operates downwardly, the upper shaft <NUM> can be lowered smoothly sliding along the lower shaft <NUM>, and this can avoid a problem from occurring caused by a direct contact of the upper shaft <NUM> with the outer surface of the lower shaft <NUM>. When the bush <NUM> is arranged, it is necessary to form a groove on the outer peripheral surface of the lower shaft <NUM>; however, since this lower shaft <NUM> is solid, a decrease of strength can be suppressed even when the groove is formed.

In this embodiment, the lower shaft <NUM> is formed solid and the upper shaft <NUM> is formed hollow, hence to suppress an increase in diameter of the first shaft <NUM>. When the lower shaft <NUM> is formed hollow and the upper shaft <NUM> is formed solid, the size in the diameter direction of the ball spline for the lower shaft is enlarged and the diameter of the first shaft <NUM> arranged outwardly is enlarged, which increases the total weight of the shaft.

However, when some increase in the diameter of the first shaft <NUM> is allowable, it does not preclude a structure in which the lower shaft <NUM> is formed hollow and the solid upper shaft <NUM> is housed into the lower shaft <NUM>. Alternatively, when the upper shaft <NUM> and the lower shaft <NUM> are both formed hollow, a wire can be passed within the hollow shaft on the internal diameter side. Further, another shaft can be added on the outer diameter side of the first shaft <NUM>, hence to increase the degree of freedom of positioning to three and more degrees.

In the embodiment, the pulley <NUM> for rotating the first shaft <NUM> is supported on the top of the base <NUM> through the rotary ball spline <NUM> and the pulley <NUM> for rotating the lower shaft <NUM> is supported on the bottom of the base <NUM> through the bearing <NUM>. Since the tension by the belt <NUM> and the belt <NUM> respectively works on the pulley <NUM> and the pulley <NUM>, the load is respectively applied to the side of the motor <NUM> and the side of the motor <NUM>. The lower shaft <NUM> in the embodiment, however, has a length from the bottom to the top of the base <NUM> and the both ends are supported by the top and the bottom of the base <NUM>. As the result, even when the load caused by the tension of the belt is added to the lower shaft <NUM> through the pulley, the position of the lower shaft <NUM> is hardly deviated. Further, the lower shaft <NUM> serves as a rail of the upper shaft <NUM> and the first shaft <NUM>, which can avoid the upper shaft <NUM> and the first shaft <NUM> from inclining; as the result, it is possible to control the stopping position of each of the reagent probes 7a and 8a accurately.

The length of the lower shaft <NUM> may be longer in a way of protruding from the pulley <NUM>; however, the longer shaft is increased in the processing cost, and therefore, the upper end of the lower shaft <NUM> is positioned within the range of the axial direction of the rotary ball spline <NUM>. Particularly, in the embodiment, the upper end of the lower shaft <NUM> is positioned within the range of the axial direction of the flange portion <NUM> of the rotary ball spline <NUM>, which improves the strength of the whole dispensing mechanism. When the lower shaft <NUM> is short, in other words, when the upper end of the lower shaft <NUM> is positioned lower than the lower end of the rotary ball spline <NUM>, the upper end of the lower shaft <NUM> easily deviates and the upper shaft <NUM> and the first shaft <NUM> may be inclined. In this case, there is a fear that the lower shaft <NUM> and the upper shaft <NUM> may be bent at the position of the slider <NUM>, resulting in a resistance in the vertical movement of the arm and an increasing abrasion of the shafts.

<FIG> is a cross-sectional view showing a state (a) before the arm is lowered and a state (b) after the arm is lowered in the dispensing mechanism according to the embodiment.

As shown in <FIG>, when the inside arm <NUM> and the outside arm <NUM> are positioned upwardly, the second shaft is extended, and the first shaft <NUM> and the upper shaft <NUM> of the second shaft are positioned upwardly from the lower shaft <NUM> of the second shaft. On the contrary, as shown in <FIG>, when the inside arm <NUM> and the outside arm <NUM> are positioned downwardly, the second shaft is shrunk and the first shaft <NUM> and the upper shaft <NUM> are positioned relatively lower than the state (a) in <FIG>.

Next, an operation of lowering the first shaft and the second shaft by the motor <NUM> in the dispensing mechanism according to the embodiment will be specifically described. <FIG> is a schematic view showing a state (a) of the shafts before the arm is lowered and a state (b) of the shafts after the arm is lowered in the dispensing mechanism according to the embodiment.

Before the arm is lowered, as shown in <FIG>, the first shaft <NUM> and the upper shaft <NUM> are positioned upwardly. Then, when the motor <NUM> is driven, the first shaft <NUM> is lowered while sliding on the rotary ball spline <NUM>. Here, the first shaft <NUM> is restricted to the position in the axial direction with respect to the upper shaft <NUM>; therefore, when the first shaft <NUM> is lowered, the upper shaft <NUM> is also lowered together with the ball spline <NUM>.

At this time, the ball spline <NUM> is lowered sliding along the lower shaft <NUM>. Then, as shown in <FIG>, the first shaft <NUM> and the upper shaft <NUM> move downwardly relatively to the lower shaft <NUM>, the lower shaft <NUM> having a smaller diameter is gradually housed into the hollow upper shaft <NUM> having a larger diameter, and when the length of the second shaft is shortened, the downward operation of the arm is finished. Here, the lower end of the lower shaft <NUM> is fixed to the base <NUM> together with the pulley <NUM>, to restrict the position in the axial direction. Therefore, in the embodiment, no part of the second shaft is protruded from the bottom of the base <NUM> and the bottom space of the base <NUM> can be effectively availed. As the result, downsizing and high performance of the automatic analyzer can be realized. The embodiment adopts a structure in which the lower end of the second shaft is not lowered even when the upper end of the second shaft is lowered, in other words, in which the second shaft is not protruded from the bottom of the base <NUM>; however, as far as a protruding portion can be smaller by shortening the length of the second shaft, some effect can be achieved.

On the contrary, as a comparison example, an operation of the dispensing mechanism having one second shaft without being divided will be described. <FIG> is a schematic view showing a state (a) of the shaft before the arm is lowered and a state (b) of the shaft after the arm is lowered, in the dispensing mechanism of the comparison example.

Before the arm is lowered, as shown in <FIG>, the first shaft <NUM> and the second shaft <NUM> are positioned upwardly. Thereafter, when the motor is driven, the first shaft <NUM> moves down while slidably moving the rotary ball spline <NUM>. Here, the first shaft <NUM> is restricted to the position in the axial direction with respect to the second shaft <NUM>; therefore, when the first shaft <NUM> moves down, the second shaft <NUM> also moves down.

At this time, the second shaft <NUM> moves down while slidably moving the ball spline <NUM> at the bottom of the base <NUM>. Therefore, as shown in <FIG>, a part of the second shaft <NUM> is protruded from the bottom of the base <NUM> and the bottom space of the base <NUM> is restricted.

The first embodiment is designed in that the outside arm <NUM> as the second arm is connected to the distal end of the inside arm <NUM> as the first arm and that each of the reagent probes 7a and 8a is mounted to the distal end of the outside arm <NUM>. Therefore, it is possible to achieve the positioning at one stopping position with two degrees of freedom. On the other hand, in a second embodiment, arms each having one degree of freedom are vertically mounted in two stages and each arm can be rotated independently according to the first shaft and the second shaft.

<FIG> is a perspective view of a dispensing mechanism according to the second embodiment. As shown in <FIG>, the dispensing mechanism according to this embodiment has two reagent probes 7a or 8a. The lower stage arm <NUM> as the first arm is rotated to position the reagent probe according to the first shaft <NUM>, and the upper stage arm <NUM> as the second arm is rotated to position the reagent probe according to the second shaft (the upper shaft <NUM> and the lower shaft <NUM>). The reagent probes 7a or 8a are respectively mounted to the distal ends of the arms, and the lower stage arm <NUM> and the upper stage arm <NUM> are vertically moved in the same way at the same time and can be rotated independently at the same time. Since the arms are divided vertically in the two stages, the reagent probe 7a or 8a of the upper stage arm <NUM> is longer than the reagent probe 7a or 8a of the lower stage arm <NUM> so that the distal end of the reagent probe 7a or 8a of the upper stage arm <NUM> may be positioned at the same height as that of the lower stage arm <NUM>.

According to the embodiment, it is possible to realize an automatic analyzer having a two degree of freedom arm that can set the two positions at the same time and that can dispense an object at the two positions at the same time. Further, since a single dispensing mechanism can dispense an object at two positions at the same time, the number of the dispensing mechanisms in the automatic analyzer can be reduced.

In addition, by adding a hollow shaft, the degree of freedom in the positioning can be increased. For example, when two hollow shafts are added and another arm is connected to each of the distal ends of the lower stage arm <NUM> and the upper stage arm <NUM>, it is possible to position each probe not only with the two degrees of freedom but also at the two positions at the same time, hence to improve the accuracy of the stopping position.

Claim 1:
An automatic analyzer comprising:
a dispensing mechanism (<NUM>, <NUM>, <NUM>, <NUM>) driving a probe (7a, 8a, 11a, 12a) for a specimen or a reagent;
a first arm (<NUM>; <NUM>) and a second arm (<NUM>; <NUM>) of two degrees of freedom supporting the probe (7a, 8a, 11a, 12a);
a first shaft (<NUM>) and a second shaft (<NUM>, <NUM>) that support the first and second arms (<NUM>, <NUM>; <NUM>, <NUM>) and transmit power to the first and second arms (<NUM>, <NUM>; <NUM>, <NUM>);
a plurality of motors (<NUM>, <NUM>, <NUM>) that give power allowing the first and second shafts (<NUM>, <NUM>, <NUM>) to be rotated and vertically moved, the motors (<NUM>, <NUM>, <NUM>) including a first motor (<NUM>) for rotating the first shaft (<NUM>), a second motor (<NUM>) for rotating the second shaft (<NUM>, <NUM>), and a third motor (<NUM>) for vertically moving the first shaft (<NUM>) and the second shaft (<NUM>, <NUM>); and
a base (<NUM>) that supports a lower end of the second shaft (<NUM>, <NUM>),
characterized in that
the second shaft (<NUM>, <NUM>) is divided in an axial direction in an upper shaft (<NUM>) and a lower shaft (<NUM>) having different diameters,
at the time of lowering the first and second arms (<NUM>, <NUM>; <NUM>, <NUM>) by the power of the third motor (<NUM>), the upper and lower shafts (<NUM>, <NUM>) are housed inside each other, whereby the second shaft (<NUM>, <NUM>) is shortened, and
the second motor (<NUM>) for second shaft rotation that gives power to rotate the second shaft (<NUM>, <NUM>) is arranged on a lateral side of the base (<NUM>).