Article sorting apparatus

1. An article sorting apparatus comprising:

a conveyance path extending in a first conveyance direction;

at least one conveyance unit including a belt that forms a load surface on which an article is placed and a driving portion for driving the belt, the conveyance unit being configured to move along the conveyance path and to convey the article placed on the load surface in a second conveyance direction that intersects the first conveyance direction;

a loading portion configured to load the article onto the load surface of the at least one conveyance unit;

a sorting portion configured to sort the article received from the at least one conveyance unit;

a weight information detector including a sensor provided on the conveyance unit configured to detect weight information correlated with a weight of the article that is transferred from the loading portion onto the load surface; and

a controller configured to control driving of the driving portion in accordance with the weight information detected by the weight information detector, thereby transferring the article placed on the load surface to the sorting portion.

2. The apparatus according to claim 1 , wherein the driving portion includes a rotating member configured to rotate as the belt is driven, the weight information detector includes a rotation angle sensor configured to detect a rotation angle of the rotating member, and during transfer of the article from the loading portion to the belt in a driven state, the weight information detector detects the weight information correlated with the weight of the article using information on the rotation angle of the rotating member that is detected by the rotation angle sensor during a period of time between a start of deceleration and a stop of the belt.

3. The apparatus according to claim 1 , wherein the weight information detector includes a strain gauge configured to detect a magnitude of a strain in the conveyance unit, and during transfer of the article from the loading portion to the belt in a driven state, the weight information detector detects the weight information correlated with the weight of the article using information on the magnitude of the strain in the conveyance unit that is detected by the strain gauge.

4. The apparatus according to claim 3 , wherein the strain gauge is disposed in a uniaxial stress region provided in the conveyance unit.

5. The apparatus according to claim 1 , wherein a support member for supporting the belt from a back face side relative to the load surface is provided, the weight information detector includes a pressure sensor configured to detect a magnitude of a pressure exerted on the support member by the belt, and during transfer of the article from the loading portion to the belt in a driven state, the weight information detector detects the weight information correlated with the weight of the article using information on the magnitude of the pressure exerted by the belt that is detected by the pressure sensor.

6. The apparatus according to claim 1 , wherein during transfer of the article placed on the load surface to the sorting portion, the controller is configured to advance a driving start timing of the driving portion such that the larger the weight of the article relative to a reference weight, the more the driving start timing is advanced, the weight of the article being obtained from the weight information, or to delay the driving start timing such that the smaller the weight of the article relative to the reference weight, the more the driving start timing is delayed, the weight of the article being obtained from the weight information.

7. The apparatus according to claim 1 , wherein during transfer of the article placed on the load surface to the sorting portion, the controller is configured to increase a driving force of the driving portion such that the larger the weight of the article relative to a reference weight, the larger the driving force, the weight of the article being obtained from the weight information, or to decrease the driving force such that the smaller the weight of the article relative to the reference weight, the smaller the driving force, the weight of the article being obtained from the weight information.

8. The apparatus according to claim 1 , wherein the driving portion is a servo motor, and during transfer of the article placed on the load surface to the sorting portion, the controller is configured to change a control gain in feedback control of the driving portion such that the larger the weight of the article relative to a reference weight, the larger the control gain, the weight of the article being obtained from the weight information, or to change the control gain such that the smaller the weight of the article relative to the reference weight, the smaller the control gain, the weight of the article being obtained from the weight information.

9. An article sorting apparatus comprising:

a conveyance path extending in a first conveyance direction;

at least one conveyance unit including a belt that forms a load surface on which an article is placed and a driving portion for driving the belt, the conveyance unit being configured to move along the conveyance path and to convey the article placed on the load surface in a second conveyance direction that intersects the first conveyance direction;

a loading portion configured to load the article onto the load surface of the at least one conveyance unit;

a sorting portion configured to sort the article received from the at least one conveyance unit;

a weight information detector configured to detect weight information correlated with a weight of the article that is transferred from the loading portion onto the load surface; and

a controller configured to control driving of the driving portion in accordance with the weight information detected by the weight information detector, thereby transferring the article placed on the load surface to the sorting portion,

wherein the driving portion includes a motor, the weight information detector includes a current sensor configured to detect a current flowing through the motor, and during transfer of the article from the loading portion to the belt in a driven state, the weight information detector detects the weight information correlated with the weight of the article using information on a regenerative current flowing through the motor that is detected by the current sensor during deceleration of the belt.

10. An article sorting apparatus comprising:

a conveyance path extending in a first conveyance direction;

at least one conveyance unit including a belt that forms a load surface on which an article is placed and a driving portion for driving the belt, the conveyance unit being configured to move along the conveyance path and to convey the article placed on the load surface in a second conveyance direction that intersects the first conveyance direction;

a loading portion configured to load the article onto the load surface of the at least one conveyance unit;

a sorting portion configured to sort the article received from the at least one conveyance unit;

a weight information detector configured to detect weight information correlated with a weight of the article that is transferred from the loading portion onto the load surface; and

a controller configured to control driving of the driving portion in accordance with the weight information detected by the weight information detector, thereby transferring the article placed on the load surface to the sorting portion,

wherein the weight information detector includes an acceleration sensor configured to detect an amplitude of vibration of the conveyance unit, and during transfer of the article from the loading portion to the belt in a driven state, the weight information detector detects the weight information correlated with the weight of the article using information on the amplitude of the vibration of the conveyance unit that is detected by the acceleration sensor.