Abstract:
A conveyor controlling device which can reduce production costs and can be easily attached. The presence or absence of a load in the conveyor portion in the local zone and a plurality of selected downstream zones is detected. The controlling device stops the drive of the local corresponding zone when a signal indicates the presence of loads in the local zone and in all of the downstream zones. The conveyor controlling device drives the local corresponding zone when the downstream presence signal indicates that at least one downstream zone is vacant. This controlling device provides a simple method for controlling an accumulating conveyor.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a conveyor controlling device for controlling driving of local zones that are divided along the transferring direction of a conveyor and can be independently driven, and a conveyor apparatus. 
     Conventionally, this type of conveyor apparatus is provided with a conveyor having respective zones which are divided along the transferring direction of the conveyor and can be independently driven. A sensor and a solenoid valve for controlling transmission of power of a drive motor are disposed in the respective zones. The sensors and solenoid valves are connected to a central control panel via wires. The control panel controls the solenoid valve on the basis of signals from the sensors. 
     However, a large number of wires are required between the control panel and the solenoid valves and sensors. The wiring is thus complicated, and increases the difficulty of installing the conveyor apparatus at the installation site. 
     Therefore, as has been described in, for example, Japanese Laid-Open Patent Publication No. 172549 of 1995, a construction is known, in which a sub-controller internally having a CPU is installed in each respective zone. Each sub-controller includes a sensor and a solenoid valve connected to its respective zone. Each sub-controller is connected to a central controller panel. 
     However, as has been described in Japanese Laid-Open Patent Publication No. 172549 of 1995, if a central controller panel is provided in addition to a sub-controller, settings should be made both in the central controller panel and sub-controllers. The need for multiple settings increases the difficulty and production cost in using the conveyor. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     The present invention was developed in view of the above problems, and it is therefore an object of the invention to provide a conveyor controlling device and a conveyor apparatus, which can be simply installed and can reduce production costs. 
     A conveyor controlling device according to the invention has respective zones which are divided along the transferring direction of a conveyor and can be independently driven, which is disposed in said respective zones, which comprises local load inputting portions each secured corresponding to a local zone, by which whether or not a load to be transferred exists is inputted in said local zone; a plurality of downstream load inputting portions secured corresponding to selected downstream zones, by which whether or not a load to be transferred exists is inputted in said corresponding zone; and a means for controlling so as to stop the drive of a corresponding local zone when a signal instructing that there is a load to be transferred is inputted from all of said local load inputting portions and downstream load inputting portions, and so as to drive the corresponding local zone when a signal is not inputted, which instructs that there is no load to be transferred, in any of the local load inputting portions and downstream load inputting portions. 
     The conveyor controller device inputs whether or not a load to be placed in a local zone exists into a local load input portion, inputs whether or not loads to be placed in a plurality of selected downstream zones exist in a plurality of downstream load input portions, stops driving the local corresponding zones when a signal is inputted, from all of the local load input portion and downstream load input portions, that a load exits, and drives the local corresponding zone when no signal is inputted, which instructs that no load exists in either the local load input portion and downstream load input portions, whereby it is possible to control the respective zones of a conveyor with only a simple construction. 
     A conveyor controlling device according to the invention is featured in that, in addition to the conveyor controlling device as set forth above, the controlling means is provided with an OR circuit which generates an output when an output is issued from the local load inputting portion and any one of the downstream load inputting portions, and an operational amplifier which drives a local zone when an output is issued from said OR circuit. 
     A conveyor controlling device according to the invention includes, respective zones which are divided along the transferring direction of a conveyor and can be independently driven, comprises local load inputting portions each secured corresponding to a local zone, by which whether or not a load to be transferred exists is inputted in said local zone; a plurality of downstream load inputting portions secured corresponding to selected downstream zones one after another, by which whether or not a load to be transferred exists is inputted in said corresponding zone; a downstream load selecting switch for turning on and off the input of a signal from the downstream load inputting portions; and a means for controlling so as to stop the drive of a corresponding local zone when a signal instructing that there is a load to be transferred is inputted from all of said local load inputting portions and downstream load inputting portions selected by said downstream load selecting switch, and so as to drive the corresponding local zone when a signal is inputted, which instructs that there is no load to be transferred, in any of the local load inputting portions and downstream load inputting portions which are selected by said downstream load selecting switch. 
     The conveyor controller device inputs whether or not a load to be placed in a local zone exists into a local load input portion, inputs whether or not loads to be placed in a plurality of downstream zones selected by the downstream load selecting switch exist into a plurality of downstream load input portions, stops drive of local corresponding zones when a signal is inputted, from all of the local load input portion and downstream load input portions selected by the downstream load selecting switch, that a load exits, and drives the local corresponding zone when no signal is inputted, which instructs that no load exists in either the local load input portion and downstream load input portions selected by the downstream load selecting switch, whereby it is possible to control the respective zones of a conveyor with only a simple construction. 
     A conveyor controlling device according to the invention, in addition to the conveyor controlling device as set forth in the first paragraph of this section, the controlling means is provided with an OR circuit which generates an output when an output is issued from the local load inputting portion and any one of the downstream load inputting portions selected by said downstream load selecting switch, and an operational amplifier which drives a local zone when an output is issued from said OR circuit, whereby zones of a conveyor can be controlled by OR circuits and operational amplifiers with a simple construction. 
     A conveyor controlling device according to the invention, in addition to the conveyor controlling device as set forth in the foregoing paragraphs further comprises a plurality of downstream FULL inputting portions which are provided in downstream zones and input FULL from the corresponding zones; wherein said controlling means outputs a FULL signal when a signal instructing that there is a load is inputted from all of the local load inputting portions and downstream FULL inputting portions, wherein by inputting FULL from zones corresponding to the downstream FULL input portions, a FULL signal is outputted when a signal is inputted, from all of the local load input portions and downstream load input portions, which instructs that a load exists, and FULL can be easily detected. 
     A conveyor controlling device according to the invention which, in addition to the conveyor controlling device as set forth in any one of the first four paragraphs of this section, further includes a plurality of downstream FULL inputting portions which are secured corresponding to the downstream zones one after another and input, from zones corresponding thereto, that the zones are FULL; and a downstream FULL selecting switch for turning on and off input of a signal from the downstream FULL inputting portions, wherein said controlling means outputs a FULL signal when a signal instructing that there is a load is inputted from all of the local load inputting portions and downstream FULL inputting portions selected by said downstream FULL selecting switch. Therefore, by inputting FULL from the zone corresponding to the downstream FULL input portions selected by the downstream FULL selecting switch, a FULL signal is outputted when a signal instructing that a load exists is inputted from all of the local load input portions and the downstream FULL input portions selected by the downstream FULL selecting switch, whereby FULL can be easily detected. 
     A conveyor controlling device according to the invention includes, in addition to the conveyor controlling device as set forth in any of the foregoing paragraphs, further comprises a plurality of downstream FULL CANCEL inputting portions which are secured in downstream zones and input from zones corresponding thereto that the zones are not fill, wherein said controlling means outputs a FULL CANCEL signal when a signal is inputted, which instructs that a load exists in neither of the local load inputting portions or the downstream FULL CANCEL inputting portions. Therefore, by inputting FULL CANCEL from the zones corresponding to the downstream FULL CANCEL input portions, a FULL CANCEL signal is outputted when a signal is inputted, which instructs that no load exists in either of the local load input portion or the downstream FULL input portions. Thus, FULL CANCEL can be easily detected. 
     A conveyor controlling device according to the invention, in addition to the conveyor controlling device as set forth in any of the first six paragraphs in this section, further comprises a plurality of downstream FULL CANCEL inputting portion which are secured corresponding to the downstream zones one after another and input, from zones corresponding thereto, that the zones are not FULL; and a downstream FULL CANCEL selecting switch for turning on and off an input of a signal from said downstream FULL CANCEL inputting portion; wherein said controlling means outputs a FULL CANCEL signal when a signal is inputted, which instructs that there is no load in either of the local load inputting portions or the downstream FULL CANCEL inputting portion selected by the downstream FULL CANCEL selecting switch. Therefore, by inputting FULL CANCEL from a zone corresponding to the downstream FULL CANCEL input portion selected by the downstream FULL CANCEL selecting switch, a FULL CANCEL signal is outputted when a signal is inputted, which instructs that no load exists in the local load input portion and the downstream FULL CANCEL input portion selected by the downstream FULL CANCEL selecting switch, whereby the FULL CANCEL can be easily detected. 
     A conveyor controlling device according to the invention, in addition to the conveyor controlling device as set forth in any one of the foregoing paragraphs, it further comprises a drive input portion which inputs a signal forcedly driving a local zone, wherein said controlling means forcedly drives the local zone when a signal is inputted in said drive input portion, whereby forced removal of the load is enabled by inputting a signal into the drive input portion. 
     A conveyor controlling device according to the preceding paragraph which, in addition to the conveyor controlling device as set forth in the preceding paragraph and any one of the first eight paragraphs of this section, further comprises a drive input portion which inputs a signal forcedly driving a local zone, and a drive selecting switch for turning on or off an input of a signal from said drive input portion; wherein said controlling means forcedly drives the local zone when a signal is inputted in said drive input portion in a state where the drive selecting switch is turned on, whereby if a signal is inputted into the drive input portion in a state where a signal from the drive input portion is inputted by the drive selecting switch, the local zone can be forcedly driven, and forced removal of a load is enabled by inputting a signal into the drive input portion. 
     A conveyor apparatus according to the foregoing paragraph further including a plurality of zones along the transferring direction of the conveyor, which are divided into a plurality along the transferring direction and can be independently driven; and conveyor controlling devices described in any one of the foregoing paragraphs of this section, which are disposed corresponding to these zones, whereby respective actions can be brought about. 
     The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a circuit diagram showing one embodiment of a conveyor controlling device according to the invention. 
     FIG. 2 is an explanatory view showing a connected state in FIG.  1 . 
     FIG. 3 is an explanatory view showing a conveyor apparatus in FIG.  1 . 
     FIG. 4 is a side elevational view showing the actions of the same conveyor apparatus. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, a description is given of an accumulation conveyor which is one of the embodiments of a conveyor apparatus according to the invention, with reference to the accompanying drawings. 
     As shown in FIG. 1, an accumulation conveyor, shown generally at  1 , is divided into, for example, eleven zones, that is, divided into eleven zones of conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11 . Also, the accumulation conveyor is not limited to that in which a single conveyor is divided into a plurality of zones, but may be applicable to that in which the entire conveyor is used as a single zone. 
     Further, the accumulation conveyor  1  has a plurality of rotatable transfer rollers  3  each having a rotating shaft in a direction orthogonal to the transferring direction of a load O to be transferred. Also, an elevatable drive portion  4  is formed at each of the zones of the transfer rollers  3 . The drive portion  4  can be engaged with or disengaged from the transfer rollers  3 , wherein the drive portion  4  is provided with drive rollers  5  which rotate the transfer rollers  3  by the drive portion  4  being engaged with the transfer roller  3 . The drive rollers  5  can be elevated by an elevating device  6 , which is elevated by solenoid valves  7   1a ,  7   1b ,  7   2  through  7   11 . The transfer rollers  3  are driven and rotated by the drive motor  5  when the elevating device  6  is elevated, as shown to the left in FIG.  4 . The drive rotor  5  is separated from the transfer rollers  3  when the elevating device  6  is lowered, as shown to the right of FIG.  4 . In the lowered condition of elevating device  6 , the transfer rollers  3  are not rotated. 
     Photoelectric sensors  8   1a  and  8   1b  in the conveyor portion  2   1a  detect the presence of a load O at two points, one at the upstream side and the other at the downstream side. In the conveyor portions  2   1b ,  2   2  through  2   11 , photoelectric sensors  8   1c ,  8   2  through  8   11  are disposed only at the downstream sides. 
     A substrate  11  acts as a conveyor controlling device located, respectively, in the conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  which constitute the respective zones. 
     As shown in FIG. 1, each substrate  11  includes eight signal lines  12   1  through  12   8 . The eight signal lines each carry respective signals from like-numbered zones in other substrates  11 . Seven lines of these signal input lines  12   2  through  12   8  are, respectively, connected to signal input lines  12   1  through  12   7  of the downstream zones. Seven signal input lines  12   1  through  12   7  are, respectively, connected to signal input lines  12   2  through  12   8  of the substrates  11  of the upstream zones. DC power source lines  14 ,  15 , running signal line  16 , drivable setting line  17 , and local signal line  18  are disposed in each substrate  11 , and connected to corresponding lines in upstream and downstream neighbors. The signal input lines  12   1  through  12   8 , power source lines  14 ,  15 , running signal line  16  and drivable setting line  17  are connected to the connectors  21  and  22  at the upstream and downstream sides of the substrate  11 . A flat cable is used to connect connectors  21  and  22  to each other. 
     The power source lines  14  and  15  are connected to a power source input portion  2 . The running signal line  16  and drivable setting line  17  are connected to a drive input portion  25 . A photo transistor Q 1  for running input signals and a light emitting diode LED 1  photo-coupled to the photo transistor Q 1  are connected between the drivable setting line  17  and the power source line  14 . A photo transistor Q 2  for running input signals and a light emitting diode LED 2  photo-coupled to the photo transistor Q 2  are connected between the drivable setting line  17  and the power source line  14 . The power source lines  14 ,  15  and the running signal line  16  are connected to a local load input portion  26 . Photosensors  8   1c , and  8   2  through  8   11  are connected to the local load input portion  26 . 
     A drive output portion  27  is connected to solenoid valves  7   1a ,  7   1b  and  7   2  through  7   11  are connected to the drive output portion  27 . 
     The conveyor controlling portion (substrate)  11  is provided with a FULL output portion  28  and a FULL CANCEL output portion  29 . A series circuit of a resistor R 1 , a light emitting diode LED 3  and a photo transistor Q 3  photo-coupled to the light emitting diode LED 3  are connected to the FULL output portion  28 . A series circuit of a resistor R 2 , a light emitting diode LED 4 , and a photo transistor Q 4  photo-coupled to the light emitting diode LED 4  are connected to the FULL CANCEL output portion  29 . 
     Next, a description is given of a controlling means  31  of the substrate  11 . 
     A downstream load input portion  32  at the signal input lines  12   1  through  12   8  has pull-up resistors R 31  through R 38  connected thereto, corresponding to the signal input lines  12   1  through  12   8 . Dip switches SW 11  through SW 18  form a downstream load selecting switch  33 . The settings of dip switches SW 11  through SW 18  determine whether or not the signal on its respective line is inputted. Diodes D 11  through D 18  constituting an OR circuit  34  are connected to the signal input lines  12   1  through  12   8  in series. In addition, a pull-up resistor R 4  and a diode D 2  are connected to the local signal line  18 . The diode D 2  forms an OR circuit  35  along with the OR circuit  34 . 
     A downstream FULL input portion  36  is formed at the signal input lines  12   1  through  12   8 , wherein, corresponding to the signal input lines  12   1  through  12   8 , switches SW 21  through SW 28  each formed of a dip switch as a downward FULL selecting switch  37  for setting whether or not the signal is inputted, and diodes D 31  through D 38  constituting an OR circuit  38  are connected to the downstream FULL input portion  36  in series. A diode D 4  is connected to the local signal line  18 , and the diode D 4  forms an OR circuit  39  along with the OR circuit  38 . 
     A downstream FULL CANCEL input portion  41  is formed at the signal input lines  12   1  through  12   8 . Corresponding to the signal input lines  12   1  through  12   8 , dip switches  31  through  38  serve as a downstream FULL CANCEL selecting switch  42  to set whether or not their respective signals are inputted. Diodes D 51  through D 58  constituting an OR circuit  43  are connected in series to the downstream FULL CANCEL input portion  41 . A diode D 6  is also connected to the local signal line  18 . A diode D 6  forms an OR circuit  44  with the OR circuit  43 . 
     A power source  43  for the output of 12V is formed between the power source lines  14  and  15 . In the power source  45 , a series circuit of a diode D 7  and a capacitor C 1  is connected between the power source line  15  and power source line  14 . A capacitor C 2  and a 3-terminal regulator  46  are connected to the capacitor C 1  in parallel. A capacitor C 3  is connected to the 3-terminal regulator  45 . 
     A resistor R 6  and a resistor R 7  are connected in series, in the power source  45 . A reversal input terminal of an operational amplifier  51 , which functions as a comparator, is connected to the junction of the resistors R 6  and R 7 . A non-reversal input terminal of the operational amplifier  51  is connected to the OR circuit  35 . The non-reversal input terminal of the operational amplifier  51  is also connected to the power source line  14  via a parallel circuit of a resistor R 8  and a capacitor C 4 . The output terminal of the operational amplifier  51  is connected to the 3-terminal regulator  46  via a resistor R 11 . A diode D 11  is connected, in parallel, to the series circuit of a resistor R 12  and a light emitting diode LEDS and is connected to the base of a transistor Q 5 . The emitter of the transistor Q 5  is connected in the power source line  14 . The collector of transistor Q 5  is connected to the output terminal of the operational amplifier  51 . A diode D 12  is connected to the drive output portion  27  and is further connected to the solenoid valves  7   1a ,  7   1b , and  7   2  through  7   11 . 
     Also, the diode D 12  is connected from the running signal line  16  to the 3-terminal regulator  46  via resistors R 14  and R 15 . The point of connection of the resistors R 14  and R 15  is connected to the non-reversal input terminal of the operational amplifier  52  which functions as a comparator. A series circuit of the resistors R 16  and R 17  is connected in the power source  45 . The junction of the resistors R 16  and R 17  is connected to a non-reversal input terminal of the operational amplifier  52 . 
     A diode D 15 , emitter of the transistor Q 8 , and a series circuit of the collector of the transistor Q 8  and resistor RI  8  are connected in the power source  45 . The collector of the transistor Q 8  is connected to the non-reversal input terminal of an operational amplifier  51  via a diode D 16 . The base of the transistor Q 8  is connected to the 3-terminal regulator  46  via a resistor R 21 . The base of the transistor Q 8  is also connected to a drivable setting line  17  via a setting switch SW 4 . Setting switch SW 4  is part of a setting switch  53  formed of a resistor R 22  and a dip switch. Setting switch  53  determines whether or not a drivable signal is inputted. 
     Also, a series circuit of resistors R 23  and R 24  is connected in the power source  45 . The non-reversal input terminal of the operation amplifier  54  which functions as a comparator is connected to the junction of the resistors R 23  and R 24 . The reversal input terminal of the operational amplifier  54  is connected to the OR circuit  39 , and to the power source line  14  via a parallel circuit of the resistor R 25  and capacitor C 6 . The output terminal of the operational amplifier  54  is connected to the 3-terminal regulator  46  via a resistor R 26 . The series circuit of the resistor R 27  and light emitting diode LED 6 , and the diode D 12  are inversely connected in parallel to each other and are connected to the base of the transistor Q 6 . The emitter of the transistor Q 6  is connected to the power source line  14 . The collector of the transistor Q 6  is connected to the output terminal of the operational amplifier  53  via a diode D 17 . The transistor Q 6  is connected to the FULL output portion  28  and to the light emitting diode LED 3 . 
     A series circuit of resistors R 31  and R 32  is connected in the power source  45 . A reversal input terminal of an operational amplifier  55  which functions as a comparator is connected to junction of the resistors R 31  and R 32 . The non-reversal input terminal of the operational amplifier  55  is connected to another OR circuit  44 . The non-reversal input terminal of the operational amplifier  55  is also connected to the power source line  14  via a parallel circuit of the resistor R 33  and capacitor C 7 . The output terminal of the operational amplifier  55  is connected to the 3-terminal regulator  46  via a resistor R 34 . A series circuit of the resistor R 35 , a light emitting diode LED 7 , and diode D 18  are inversely connected in parallel to each other and are connected to the base of the transistor Q 7 . The emitter of the transistor Q 7  is connected to the power source line  14 , and its collector is connected to the output terminal of the operational amplifier  55  via a diode D 18 . The transistor Q 7  is connected to the FULL CANCEL output portion  29  and is connected to the light emitting diode LED 4 . 
     The respective substrates  11  are continuously connected to each other by a flat cable  23  as shown in FIG.  2 . Solenoid valves  7   1a ,  7   1b , and  7   2  through  7   11  are connected to the drive output portion  27  of the respective substrates  11 . Photoelectric sensors  8   1c , and  8   2  through  8   11  are connected to the local load input portions  26 . A power source of 24V DC is connected to the power input portion  24  of any one of the substrates  11 , wherein a circuit for setting DRIVE or forced operation is connected to the drive input portion  25 . 
     As described above, a circuit indicating FULL or FULL CANCEL is connected to the FULL output portion  28  and FULL CANCEL output portion  29  of any one of the substrates  11 . 
     In addition, switches SW 11  through SW 18  acting as downstream load selecting switches  33 , switches SW 21  through SW 28  acting as downstream FULL selecting switches  37 , and switches SW 31  through SW 38  acting as downstream FULL CANCEL selecting switches are used to set how many downstream zones are detected in the conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11 . Since conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  in one zone are made empty without fail if detection is carried out in the conveyor portions in only one downstream zone, a plurality of conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  in the downstream zones must be set for detection. The number of detectable conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  in the downstream zones is eight. 
     Next, a description is given of actions of the abovementioned embodiment. Either of the downstream load selecting switch  33 , downstream FULL selecting switch  37  or downstream FULL CANCEL selecting switch  42  is set so that the conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  in eight downstream zones can be detected. 
     First, the light emitting diode LED 1  is lit so that operation is enabled 
     When operating the conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  in a state where no load O exists, since none of the photoelectric sensors  8   1a ,  8   1b , and  8   2  through  8   11  of any selected zone or the local zone detect any load O, no signal flows in the signal input lines  12   1  through  12   7 , wherein an OFF state is kept from the downstream load input portion  32  and local load input portion  26 , and as the capacitor C 4  is charged by output from the OR circuit  35 , the operational amplifier  51  outputs at HIGH level, and a base current is supplied to the base of the transistor Q 5  to cause the transistor Q 5  to be turned on. Therefore, the solenoid valves,  7   1a ,  7   1b , and  7   2  through  7   11  are turned on. This raises the drive roller  5  into contact with the transfer roller  3  to cause transfer roller  3  to rotate. This places the load O in a transferable state. 
     In addition, in this state, a signal flows in the signal input lines  12   1  through  12   7 , the signal is inputted by either of the downstream FULL input portion  36  or the local load input portion  26 . As the OR circuit  39  output charges the capacitor C 6 , the operational amplifier  55  outputs a LOW level output. This supplies a base current to the base of the transistor Q 7 . As a result, the transistor Q 7  remains in an OFF state. Therefore, since neither of the conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  of either of the selected zone and local zone is FULL with the load O, no FULL signal is outputted. 
     In this state, a signal flows in the signal input lines  12   1  through  12   7 . No signal is inputted from either of the downstream FULL CANCEL input portion  36  or the local load input portion  26 . Since the OR circuit  44  does not produce an output, the capacitor C 7  is charged via a resistor R 5 . When the voltage on capacitor C 7  rises to a level exceeding the reference voltage at the junction of resistors R 31  and R 32 , the operational amplifier  55  enters a HIGH level. A base current is supplied to the base of the transistor Q 7 . Then, since the transistor Q 7  is turned on and no load O exists in the conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  in either of a selected zone or local zone, a FULL CANCEL signal is generated. 
     Even though this state is continued and a load O is positioned in a part of the downstream side conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11 , the OR circuit  35  produces an output. Therefore, since the transistor Q 5  remains in an ON state, the solenoid valves  7   1a ,  7   1b , and  7   2  through  7   11  also maintain an ON state. The drive roller  5  is brought into contact with the transfer rollers  3  to rotate the transfer rollers  3 , whereby the load O is maintained in a transferrable state. 
     Also, since the OR circuit  44  produces an output, the operation amplifier  55  maintains a LOW level output, and the transistor Q 7  remains in an OFF state. Therefore, since any of the conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  of a selected zone and a local zone is not FULL with the load O, no FULL is indicated. 
     Since a signal flows in only some of the signal input lines  12   1  through  12   7 , a signal is inputted from the downstream FULL CANCEL input portion  41  and local load input portion  26 , wherein the OR circuit  44  produces an output to cause the operational amplifier  55  to enter a LOW level. Therefore, since no base current is supplied to the base of the transistor Q 7 , and the transistor Q 7  is turned off, a load O will exist in either of the conveyor portions  2   1a ,  2   1b ,  2   2  through  2 11 of a selected zone and a local zone, whereby FULL CANCEL is not indicated. 
     When a load in either of the selected conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  which will be an object is transferred, all the photo-electric sensors  8   1a ,  8   1b , and  8   2  through  8   11  of the selected zones and local zone detect the load O. Therefore, the signal flows in all the signal lines  12   1  through  12   7 , either of the downstream load input portions  32  or the local load input portion  26  is turned on, and no signal is outputted from the OR circuit  35 . Then, the operation amplifier  51  outputs a LOW level signal, and no base current is supplied to the base of the transistor Q 5 . The transistor Q 5  thus enters an OFF state. Accordingly, the solenoid valves  7   1a ,  7   1b , and  7   2  through  7   11  enter an OFF state,.wherein the drive roller  5  remains out of contact with the transfer rollers  3 , whereby the transfer rollers  3  do not rotate to move the load O. Thereby, the load O is prevented from being brought into collision with the preceding load O located in its downstream side. 
     Also, in this state, no signal flows into the signal input lines  12 , through  12   7 , and no signal is inputted from either of the downstream FULL input portion  36  or the local load input portion  26 . Since no signal is outputted from the OR circuit  39 , the operation amplifier  55  outputs a HIGH level signal, and base current is supplied to the base of the transistor Q 7 . Since the transistor Q 7  is turned on, and the conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  of the selected zone and the local zone are FULL with loads O, the FULL signal is generated. 
     Further, in this state, no signal flows in the signal input lines  12   1  through  12   7 , and a signal is inputted from all of the downstream FULL CANCEL input portions  41  and local load input portion  26 , wherein the OR circuit  44  outputs a signal, and the operational amplifier  55  outputs a LOW level signal, and no base current is supplied into the base of the transistor Q 7 . Since the transistor Q 7  is turned off and loads O exists in all the conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  of the selected zones and local zone, no FULL CANCEL signal is generated. 
     As a load O is removed from any one of the selected downstream conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11 , a signal is outputted from the OR circuit  35  to cause the transistor Q 5  to be turned on, and the solenoid valves  7   1a ,  7   1b , and  7   2  through  7   11  are accordingly turned on, wherein the drive roller  5  is brought into contact with the transfer rollers  3  to rotate the transfer rollers  3 , whereby the loads O is transferrable. Thus, the conveyor controlling device detects whether or not a load O exists in eight downstream conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  at maximum. If the device detects that no load is left in any of these conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11 , a transfer action can be efficiently carried out by actuating the local conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11 . 
     Since the OR circuit  44  outputs a signal, the operational amplifier  55  maintains LOW level output, and the transistor Q 7  maintains an OFF state, wherein since the conveyor portions  2   1a ,  21 b,  2   2  through  2   11  of either of the local zone or the selected zone is not FULL with loads O, no FULL is indicated. 
     Further, since a signal flows into only a part of the signal input lines  12   1  through  12   7 , a signal is inputted from a part of the downstream FULL CANCEL input portion  41  and local load input portion  26 , and the OR circuit  44  outputs a signal, whereby the operational amplifier  55  outputs a LOW level signal, and no base current is supplied into the base of the transistor Q 7  to cause the transistor Q 7  to be turned off. Therefore, since a load O exists in the conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  of either of the selected zone or the local zone, no FULL CANCEL is indicated. 
     A description is given below of forced removal of a load O on the conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11 . 
     First, the switch SW 4  of the conveyor portions  2   1a ,  2   1b ,  2   2  through  2   11  at which forced removal is carried out is closed in advance. This turns on the light emitting diode LED 2  indicating forced removal. 
     In this state, a base current flows into the transistor Q 8  thereby turning on the transistor Q 8 . Voltage is applied from the collector of the transistor Q 8  to the non-reversal input terminal of the operational amplifier  51  via a diode D 16 . Operational amplifier  51  outputs a HIGH level signal regardless of the output of the OR circuit  35 . This supplies a base current to the transistor Q 5  to cause the transistor Q 5  to be turned on. The solenoid valves,  7   1a ,  7   1b , and  7   2  through  7   11  are turned on, and the drive roller  5  is brought into contact with the transfer rollers  3  to rotate the transfer rollers  3 , whereby the load O is transferrable to enable forced removal. Thereafter, the light emitting diode LED 2  is turned off to terminate the forced removal. 
     According to the above conveyor controlling device, whether or not a load exists in the local zone is inputted into the local load input portion, whether or not a load exists in a plurality of selected downstream zones is inputted into a plurality of downstream load input portions, wherein the controlling means stops drive of the local corresponding zone when a signal indicating that a load exists is inputted from all of the local load input portion and downstream load input portions is inputted, and drives the local corresponding zone when no signal is inputted, which instructs that no load exists in any one of the local load input portion and downstream load input portion, whereby the respective zones of the conveyor can be controlled with a simple construction. 
     According to the conveyor controller device, the respective zones of the conveyor can be controlled by the OR circuit and operational amplifiers with a simple construction. 
     According to the conveyor controlling device, whether or not a load exists in the local zone is inputted into the local load input portion, whether or not a load exists in a plurality of downstream zones selected by the downstream load selecting switch is inputted into a plurality of downstream load input portions, wherein the controlling means stops drive of the local corresponding zone when a signal instructing that a load exists is inputted from all of the local load input portion and downstream load input portions selected by the downstream load selecting switch, and drives the local corresponding zone when no signal is inputted, which instructs that no load exists in any one of the local load input portion and downstream load input portions selected by the downstream load selecting switch, whereby the respective zones of the conveyor can be controlled with a simple construction. 
     According to the conveyor controlling device, the respective zones of the conveyor can be controlled by the OR circuit and operational amplifiers with a simple construction. 
     According to the conveyor controlling device, if, by inputting FULL from zones corresponding to the downstream FULL input portions, a signal instructing that a load exists is inputted from all of the local load input portions and downstream FULL input portions, a FULL signal is outputted, and the FULL condition can be easily detected. 
     According to the conveyor controller device, if, by inputting FULL from the zone corresponding to the downstream FULL input portion selected by the downstream FULL selecting switch, a signal, which instructs that a load exists in all of the local load input portion and downstream FULL input portions selected by the downstream FULL selecting switch, is inputted, a FULL signal is outputted, and the FULL condition can be easily detected. 
     According to the conveyor controlling device, if, by inputting FULL CANCEL from the zone corresponding to the downstream FULL CANCEL input portion, a signal which instructs that no load exist in any one of the local load input portion and downstream FULL input portions is inputted, a FULL CANCEL signal is outputted, and the FULL CANCEL condition can be easily detected. 
     According to the conveyor controlling device if, by inputting FULL CANCEL from the zone corresponding to the downstream FULL CANCEL input portions selected by the downstream FULL CANCEL selecting switch, a signal instructing that no load exists in any one of the local load input portions and downstream FULL CANCEL input portions selected by the downstream FULL CANCEL selecting switch is inputted, a FULL CANCEL signal is outputted, and the FULL CANCEL condition can be easily detected. 
     According to the conveyor controlling device, if a signal is inputted into the drive input portion, the device induces the driving of the local zone, whereby induced removal can be carried out by inputting a signal in the drive input portion. 
     According to the conveyor controlling device, if a signal is inputted into the drive input portion in a state where a signal is inputted from the drive input portion by the drive selecting switch, the device induces the driving of the local zone, and forced removal can be carried out by inputting a signal into the drive input portion. 
     According to the conveyor controlling device, a plurality of conveyor controlling devices are provided, disposed corresponding to the zones consisting of at least a part of the conveyor, which are divided into a plurality along the transferring direction and can be independently driven. Therefore, respective effects can be brought about. 
     Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defmed in the appended claims.