MXPA99003728A - Accumulac conveyor control system - Google Patents

Abstract

An accumulation conveyor control system includes a number of accumulation zone conveyors, each equipped with a control number coupled with an electronically controlled clutch. The system includes a motor linked to each accumulation conveyor to activate the conveyor rollers. The clutch links a drive roller on each conveyor with the motor through a drive member such as a chain. The control module controls the operation of the conveyors by perceiving the presence or absence of an item in the path of one of more of the article sensors. When the path is blocked meaning the presence of an item, the module sends an upstream signal and receives downstream zone signals to control the operation of the roller for each zone. The system allows a unitary installation of a number of zones using an individual energy source and without the need for mechanical devices such as switches, activators or PL

Description

ACCUMULATION CONVEYOR CONTROL SYSTEM Field of the Invention The present invention is directed to a conveyor control system and, in particular, to a system employing zone control modules that are linked together to the operation of the control conveyor without the need for a PLC or devices. mechanical actuators.

BACKGROUND OF THE INVENTION Traditional "zero pressure" pallet accumulation conveyors (PACs) have used sensors and mechanical actuators. In one mode, as a product moves into an area of these conveyors, a mechanical sensor is activated, the sensor linked to a mechanical actuator. The actuator then reacts with a clutch mechanism of the zone either to enable or disable the movement of the zone. Using this concept, the conveyor motors typically run continuously and the conveyor is usually noisy due to the mechanical action of the zone. When these mechanical installations are not reliable or desirable, electrical actuator sensors have been used. These devices have typically been connected to an external programmable logic controller (PLC). Then, software is implemented that allows the PLC to control the conveyor in a similar way. Using these concepts results in unusually long fixing times for either adjustment and / or wiring. An example of an accumulation conveyor is described in U.S. Patent No. 5,042,644 to Davis. This patent discloses a zero pressure accumulation conveyor using an activator assembly for accumulation control. The activator assembly is positioned along the conveyor stroke and is coupled to cam roller arms and valve bodies. The depression of the activating assembly presses the valve body, allowing air to pass from an air supply to a brake assembly supply. The brake assembly cylinder then restricts the torque tube thus isolating the driving force imparted by the drive shaft to the conveyor rollers. U.S. Patent No. 5,060,785 to Garrity discloses a control arrangement for a control conveyor having a plurality of zones, each zone including an electrically operated sensor. A logic circuit is associated with each sensor, the logic circuit comprising a first input, a second input from the zone sensor, a first output that sends a signal to the trigger of that zone and a second output that sends a signal to the input for the next area. A circuit for each electrical sensor communicates with the circuit before and after it controls the system. In this system, electronic sensors are used to indicate the presence of an article in a given area. When the electrical sensor senses an article that blocks the perception path, the signal interacts with the logic circuit to control the operation of the accumulation conveyor. Accumulation conveyors that use sensors and mechanical actuators are not without their disadvantages. First, in any system, the actuator reacts with a clutch mechanism in the zone either to enable or disable the movement of the conveyor in that zone. Using that system, conveyor motors typically run continuously. In addition, the conveyor is usually noisy due to the mechanical action of the area. Although these mechanical systems have been replaced by electrical systems such as those described in the Garrity patent, these electrical systems are not without their disadvantages. Electrical systems that contain logic circuits take an unusually long time for fixing due to adjustments and / or wiring. In view of the above-noted disadvantages, there is a need to provide accumulation conveyor controls, which overcome the disadvantages of the prior art. In response to this need, the present invention provides an accumulation conveyor control, which eliminates both mechanical control such as activating mechanisms, pneumatic systems, and logic circuit control systems.

Brief Description of the Invention Accordingly, it is a first object of the present invention to provide an improved accumulation conveyor control system. Another object of the present invention is a control module for each zone of an accumulation conveyor. A further object of the present invention is an accumulation conveyor system, which eliminates the need for mechanical circuits and programmable logic circuits. Yet another object of the present invention is a method for accumulating articles on an accumulation conveyor without the need for controls requiring mechanical assistance and / or software implementation. Other objects and advantages of the present invention will become apparent as its description proceeds. To satisfy the above objects and advantages, the present invention provides an improvement in accumulation conveyor system comprising a plurality of conveyor zones, the conveyor zones including an infeed conveyor zone, at least one conveyor zone intermediate, and an exit conveyor zone, each zone having at least one driven roller and a plurality of rear rollers, the driven roller linked to an impeller through a clutch mechanism. In one aspect of the invention, the improved system comprises a sensor for each zone, each sensor is capable of detecting the presence or absence of an article in a respective zone, and a solenoid for each zone. Each solenoid is linked to each zone clutch mechanism. A relay to energize or de-energize the selonoid to electrically actuate or deactivate the clutch mechanism of each zone, is provided, the operation of the relay based on the presence or absence of an article in a space of each zone and in the presence or absence of an article in the space of a downstream area. The actuation of the clutch mechanism allows the operation of the zone roller and the deactivation of the clutch mechanism that prevents the operation of the zone roller. A motor control center can be provided to link an individual power source to a single motor, the motor control center including a transformer to stagger the power source to drive each control module. The motor can be linked to each clutch mechanism through a drive member. In this way, a system that has the motor, the motor control center and several zones can be installed and connected to a single power source. The motor control center may include means for driving the motor only when the presence of an article is detected for a plurality of conveyor zones. Relays for each zone may be contained in a housing and each zone solenoid may be provided with each zone clutch mechanism. The relay and solenoid of each zone can be linked through flying connections, the flying connections can be configured based on whether the zone is an input power zone, an intermediate zone, or an output power zone to determine if the space or no space energizes a respective solenoid for the operation of the zone. The solenoids can be contained in a housing that will be mounted on a frame of each zone as a control module for each zone. The housings can be equipped with quick-connect couplings and connectors to facilitate the linking of the control modules of the various zones together. In another embodiment, the conveyor control modules, input power supply and output power can also be linked to one or more PLCs to interconnect with systems other than the accumulation conveyor control system, for example, devices upstream of the conveyor input power or downstream of the output power conveyor, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS Referring now to the drawings of the invention, in which: Figure 1 is a perspective view of one embodiment of the invention showing an accumulation conveyor and a control thereof; Figure 2 shows an external view of the control module of Figure 1; Figure 3 is a schematic electrical circuit of the control module of Figure 1 with a key showing the fixings of flying connections; Figure 4 is an internal view of the module of Figure 1; Figure 5 shows a network of modules and the network linked to a motor control center; Figure 6 is a schematic electrical view of the motor control centroid of Figure 5; Figure 7 illustrates a three-zone conveyor system showing electrical circuits for each zone; Figure 8 shows a second embodiment of the control module; and Figure 9 is a schematic electrical view of the control module of Figure 8 with a key showing the fixings of the flyer connection.

Description of Preferred Modes The present invention illustrates a new solution for controlling pallet accumulation conveyors. Using electrical sensors, actuators and a zone control module, each vane accumulation conveyor zone is electrically linked to the next. A network of control modules interacts to control the entire conveyor. Mechanical devices are eliminated in the path of the items that are being transported, and a PLC is no longer required. This pallet conveyor accumulation control offers the following benefits: 1. Fixation time reduced to a minimum, adjustments are not necessary. 2. Silent operation, no mechanical sensor and the conveyor only runs when necessary. 3. Reduced costs, no PLC and complicated wiring. No air or electrical pipe is required. 4. Easy to maintain, all control modules can be the same and made of standard industrial products. Quick disconnections that allow rapid replacement of faulty components. 5. No minimum or maximum load is required. This module is designed to replace the activating roll and mechanical link for each area of the pallet as used in the prior art designs. Although the design of the invention appears to be more expensive than the conventional mechanical link, the fixing time is reduced and considerable savings are obtained in the cost of applications of the pallet accumulation conveyor which can not use activating roller mechanisms, i.e. 7.62cm (3") roller center The system of the invention is ideally suited for heavy duty applications, where conveyors carry items ranging from 227-2724 kg / load (500-6,000 lbs / load). will be described in detail later when referring to the Figures, the control module is mounted in each zone of the pallet accumulation conveyor.Each zone is linked together using an individual quick disconnect cable.The module can be configured for zones input power, output and intermediate power using flying shutters.An optional time controller can be gregado to the areas of input power and output power to allow the loading and unloading of pallet accumulation conveyor. Using this configuration, additional control devices, ie, PLCs, are no longer necessary to operate a basic pallet accumulation conveyor system. The cable interconnection is simple. After connecting each zone to the next, a 120 VAC power source is connected to the input power zone. An additional 480 VAC power supply is then supplied to the motor with all the traditional motor control and protection devices. The control module can be made of standard industrial products. The controls can be housed in a 10.16x15.24cm (4"x6" j polycarbonate enclosure.) An adjustable cable is pre-wired to connect the next zone, and a receptacle for connecting from a previous zone is provided. Quick disconnect cables are also installed for the solenoid and photoelectric cell (the photoelectric cell and reflector are included as module patents). Internally, a relay isolates the photoelectric cell from the solenoid circuit. A fuse for the solenoid is also supplied to protect against solenoid faults. Flying shutters are provided to configure the function of the modules. Referring to Figure 1, there is shown an accumulation conveyor area illustrative of an accumulation conveyor system which is designated with the reference number 10. The zone 10 includes a conveyor zone 1 including a frame 3, a roller impeller 5 and rear rollers 7. The drive roller 5 is linked to a motor (see Figure 4). Through an impeller member represented by the reference number 9 and an electronically driven clutch 11. The motor is designed to activate the drive roller 5 of each zone throughout the system. The drive roller 5 is then linked to each of the following rollers 7 so that all the rollers rotate when the motor is operating when the clutch 11 links the drive member 9 to the drive roller 5. The electrically driven clutch 11 is interconnected with the driver. drive member 9, e.g., a chain, and drive roller 5 through a sprocket or other means. The clutch 11 both engages and decouples the drive roller 5 from the drive member 9 either to rotate the rollers for a given area or to interrupt the actuation of the roller. It should be understood that the conveyor components including the drive roller 5, the following rollers 7, the drive member 9 and the frame 3 are conventional components and do not need further description to understand the invention. Each zone 10 includes a control module 20 including a housing 22 that encloses the control module components therein. A photoelectric cell sensor 23 is provided, which is linked to the control module 20 through the connector 25. The module 20 also includes a connector 27, which is connected through a quick-connect coupling (not shown) to a previous or downstream area. A connector 29 is shown which links the module 20 to the next upstream zone or zone. The connector 29 has a quick-connect coupling (not shown at the end connecting to the module 20. The other end is linked to the upstream or next region in the same way that the connector 27 is linked to the module 20. The cell sensor photoelectric 23 is of a conventional type, which senses whether there is available space between the light emitting component 31 and the reflector 33. Figure 2 illustrates the enlarged control module 20 to show greater detail In this Figure, the connector 27 it is shown with a quick connection female coupling half 28. The housing 22 also has a male quick connect coupling half 30 adapted to be connected to the female quick connect coupling half 32 of the upstream region connector 29. It is provided the connector 35, which has a coupling half of quick female connection 37 adapted to be connected to a male quick connect coupling 3 9 mounted on a clutch housing 11. The connector 35 houses the wiring as will be described in detail below, which controls a solenoid which in turn drives the clutch 11 for the operation of the conveyor. Figure 3 shows how an illustrative circuit controls the operation of the conveyor by electronically controlling the clutch 11. The control includes either driving the rollers if the space is available or stopping the operation of the area if there is no space available, so that the Items that are being transported do not make contact with each other and incur potential damage. The circuit is designated with the reference number 50. In its broadest sense, the circuit uses a relay 51 to isolate the photocell sensor 23 and a solenoid 53. The solenoid 53 also has a fuse 55 to protect against solenoid failure. Flying shutters 57 and 59 are also provided to configure the modules, depending on the location of each zone, i.e., an input power zone, and one or more intermediate zones, and an output power zone. Referring to the key of Figure 3, the handwheels 57 and 59 are connected in some way if the zone 10 is in the first input feeding zone or zone of the accumulation conveyor system, and otherwise if the zone 10 it is either located in an intermediate location in the system or in the output power zone or end zone.

More specifically, for an input power zone operation, contacts 2 and 3 are wired together as contacts 5 and 6. For an intermediate zone operation, contacts 1 and 2 are wired together, as well as contacts 4 and 5 and 6 and 7, respectively. Figure 4 more clearly shows the components within the housing 22 of the module 20. The relay 51 and the handwheels 55 and 57 are enclosed within the housing 22 with the photoelectric cell sensor 23 being located downstream of the connector 25, and the solenoid 53 being downstream of the connector 35. The control module 20 can be linked together to form a network. The control modules interact with each other to control the "normally running" conveyor. The normal travel in this case means that the conveyor motor is continuously running. This is usually an undesirable treatment, which causes unnecessary wear and noise on the conveyor. The network of the control modules can be equipped with the addition of a specialized pallet accumulation conveyor motor control center. The input power and output power zones of the conveyor are connected directly to the motor control center. This center extends the functionality of the pallet accumulation conveyor offering the following advantages: 1. A power of 120 VAC is generated towards the sensor network from the motor control center. No separate power supply is required to operate the sensors and 2. Overload and overcurrent protection devices as well as motor ignition devices are provided. No additional equipment is needed to run the conveyor. All that is needed in a simple 480 VAC power drop to run the conveyor. 3. Using the signals from the input power and output power zone, the motor is usually "sleeping". It only runs for a predetermined interval when a load occurs on the conveyor and then returns to sleep mode. Figures 5 and 6 illustrate the network control described above. Figure 5 shows an illustrative system by means of which four modules can be connected together as part of a four zone accumulation conveyor system, an input feeding zone, two intermediate zones and an output feeding zone. The control modules 20 can be grouped together with a control center 61 and an engine 63. As described above, the motor 63 is linked to the drive rollers 5 of the four zones illustrated in Figure 5 through the clutch 11 of each zone. Although not shown, each of the driving rollers 5 is then linked to the following rollers 7 of each zone for the rotation and transportation of an article. Figure 6 shows a schematic electrical circuit illustrative of the motor control center 61. A power supply of 480 volts 65 is provided to the motor 63. The power supply is controlled through the switches 67 and the motor 63 has a circuit conventional ignition and overload 69. The 480 volt power supply 65 is also connected to a transformer 71 that stages the voltage at 120 volts. This 120 volt power supply is then supplied to the control modules for operation. The motor control system may also include a sleeper system, whereby the motor 63 normally falls asleep on the basis of signals from the input power and output power zones. The engine only runs for a predetermined time when a load occurs on the conveyor and then returns to sleep mode. This sleeping system is achieved using a time delay relay 73 and 74. When the input power zone indicates that a load is present, a signal from the input power zone is sent to the motor control center and the relay 73 is energized. The motor starter reset switch 69 is activated and the motor 63 runs as much as the input power zone detects a load. When the load moves to the next relay zone 73 it is de-energized. The relay contacts 73 remain closed until the "shutdown time" sequence of the relay ends. The relay contacts 73 are then opened and the motor 63 is stopped until again the input power zone is loaded. The output power zone sends a signal of available space to the motor control center when a load has been removed from the output power zone. This signal energizes the relay 74 and activates the rheostat of the starter motor 69 and the motor 63. When the output power zone is again charged, the relay 74 is de-energized and the "off time" sequence delays the opening of the contacts on the relay 74. When the time cycle ends, the contacts for the relay 74 open and the motor 63 turns off. The cycle is repeated when a load is removed from the outlet feeding zone. Figure 7 shows a three zone accumulation conveyor system comprising zones 20A, 20B and 20C. The zone 20A represents the output power zone A, the 20B represents the intermediate zone B and the 20C represents the output power supply zone C. The electrical circuit system is shown with the appropriate flywheel connection settings for each zone. The zone 20A has contacts 2 and 3 of the connected steering wheel 57A and the contacts 5 and 6 of the connected flying connection 59A. A similar flywheel connection arrangement is shown for 20B and 20C since the flywheel settings of the output and intermediate feed zone are the same as shown, see the key in Figure 3. The input power zone 20C shows connections between contacts 1 and 2 of the flywheel connection 57C and 4 and 5 and 6 and 7 of the flywheel connection 59C. In a basic operation, the module 20 sends a signal to the upstream area to see if there is space available or not and also receives a signal from the downstream area to see if there is space available in the downstream area. Based on this input and output, the solenoids are either energized or de-energized to control the entire operation of the accumulation conveyor system. When the photosensor detects a load in the zone, the relay is de-energized so it deactivates the solenoid and stops the zone. The area is now under the control of the downstream area. The downstream area will send a signal to the upstream area when it has available space. This signal diverts the relay signal from the upstream area and activates its solenoid. Therefore, with a load in the upstream area and no downstream load, the load is allowed to continue.

For example, with a load present in zone 20B, relay 81 is de-energized and does not allow energizing of the solenoid. Without power to the solenoid, zone 20B would stop. When zone 20C has a space available, its relay 82 energizes and allows this zone to run. The signal from the relay 82 is sent to the area 20B by means of the signal 83. This signal diverts the relay 81 and energizes the solenoid zone 20B. This allows the load to move from zone 20B to zone 20C. For applications where the pallet accumulation conveyor is integrated into other system conveyors, and / or AGV system, a variation of the control module is available as shown in Figures 8 and 9. This variation offers similar characteristics as the module of base 20, however, allows the control areas of input power and input power control to be controlled through a PLC. This variation replaces the input power and output power control modules described above. The connection to a PLC control panel is achieved by using a single quick disconnect cable from the input power and output power zone. Additional sensors are added to the module as needed, such as AGV control exchange optics, over travel safety sensors, fork vehicle sensing sensors or dry contacts of other conveyor equipment.

Referring now to Figures 8 and 9, an alternative embodiment of the control module 20 of Figure 1 is shown and designated with the reference numeral 90. In this embodiment, the input power and output power zones, by example, 20A and 20C of Figure 7, can be controlled through a PLC. This variation replaces the configuration of input power supply and output power control modules as shown in Figure 3. The connection to a PLC control panel (not shown) is achieved using a fast individual connection cable 91 of the zones. Input power and output power. In this mode, additional sensors can be added to the module as necessary, such as automatically guided vehicle control exchange optics, over travel safety sensors, fork vehicle detection sensors or dry contacts of other equipment. With the system used in Figures 8 and 9, the input power and output power conveyors can be linked to other systems for control. For example, it may be desirable to link the operation of the input infeed conveyor with another conveyor system. The use of the module 90 as the input power module of the accumulation conveyor system would allow such control. Similarly, an output power zone can be equipped with the module 90 to link the output power zone to another system conveyor or the like. Figure 9 shows an illustrative circuit diagram with flyaway fixings for both input power and output power zones. This diagram also shows the circuit system for an overpass safety sensor 93, and a connection 95 for a zone training sensor. In addition to simplifying the wiring required for this type of conveyor for the embodiment of Figures 8 and 9, the total number of and / or required for a PLC to control the conveyor is significantly reduced. For example, using a configuration of a Modicon 984-145 PLC without the control module of the invention and assuming that the PLC is connected to five pallet accumulation conveyors of "10 zones", fifteen of the seventeen slots available for use are used. control the conveyor. In comparison, when using the same PLC using the control modules of the invention, only six slots of the seventeen available are used., even functionally the transporters could operate the same. This is a reduction of (9) 1/0 cards, (2) 5-slot chassis and the associated work and wiring. Although the conveyor system is usually described as a pallet accumulation control system, any type of load can be transported with the system and method of the invention. In addition, other conveyor zone systems other than those identified in Figure 1 can be used with the module control system. Similarly, other means may be used to energize or de-energize the clutch in replacement of the solenoid. Similarly, flyby connections are made using other known connections that allow each control module to be designed in its place in the total control system. As such, an invention has been described in terms of its preferred embodiments that satisfy each of the objects of the present invention set forth above and provides a new accumulation and improved conveyor control system and a module therefor, and a method to accumulate items on a conveyor. Of course, various changes and alterations from the teachings of the present invention are contemplated by those skilled in the art without departing from their intended spirit and scope. It is intended that the present invention is limited only by the terms of the appended claims.

Claims (13)

1. An accumulation conveyor control system - comprising a plurality of conveyor zones, the conveyor zones include an infeed conveyor zone, at least one intermediate conveyor zone and one exit conveyor zone, each zone having at least one drive roller and a plurality of subsequent rollers, the driving roller linked to an actuator through a clutch mechanism, the improvement is characterized in that it comprises: a) a sensor for each zone, each sensor capable of detecting the presence or absence of an article in a respective area; b) a solenoid for each zone, each solenoid linked to each zone clutch mechanism; c) a relay to energize or de-energize the solenoid to electrically activate or deactivate the clutch mechanism of each zone based on the presence or absence of an article in the space of each zone and in the presence or absence of an article in a space of a downstream zone, the actuation of the clutch mechanism allowing operation and deactivation of the zone roller of the clutch mechanism preventing operation of the zone roller.

2. The system according to claim 1, characterized in that it further comprises a motor control center further linking an individual power source to an individual motor and to each control article, the individual motor linked to each clutch mechanism through a member Accident

3. The system according to claim 2, characterized in that it also comprises means for starting the engine only when the presence of an article is detected in the plurality of conveyor zones.

4. The system according to claim 1, characterized in that the actuator comprises a single motor and an actuator member linking each clutch mechanism to the individual motor.

5. The system according to claim 1, characterized in that the relay for each zone is contained within a housing and each zone solenoid is arranged with each zone clutch mechanism.

6. The system according to claim 1, characterized in that the relay and the solenoid of each zone are linked through flying connections, the flying connections can be configured on the basis that if the zone is an input power zone, an area of intermediate power or an output power zone to determine whether or not there is space to energize a respective solenoid.

7. The system according to claim 5, characterized in that the relay and the solenoid of each zone are linked through flying connections, the flying connections can be configured on the basis that if the zone is an input power zone, an area intermediate or an output power zone to determine whether or not there is space to energize the solenoid, the flying connections are disposed within the housing.

8. The system according to claim 5, characterized in that each housing has a first connector being connected to a downstream housing through a quick-connect coupling and a second connector being connected to a solenoid in the clutch mechanism through a coupling of fast connection.

9. The system according to claim 1, characterized in that it further comprises at least one programmable logic controller linked to one or both of the input power and output power zones to control the operation of the input power zone and the power supply zone. output power in combination with an upstream -O system downstream of a plurality of conveyor zones.

10. An accumulation conveyor control system characterized in that it comprises: a) a plurality of conveyor zones, the conveyor zones including an input infeed conveyor zone, at least one intermediate conveyor zone and an output conveyor conveyor zone, each zone having at least one drive roller and a plurality of subsequent rollers , the drive roller linked to an impeller through a clutch mechanism, wherein the impeller comprises an individual motor and an impeller member linking each clutch mechanism to the individual motor, b) a sensor for each zone, each sensor capable of detect the presence or absence of an article in a respective zone, c) a selonoid for each zone, each solenoid linked to each zone clutch mechanism; d) a relay to energize or de-energize the solenoid to electrically activate or deactivate the clutch mechanism in each zone based on the presence or absence of an article in the space of each zone and the presence or absence of an article of a current zone down, the clutch mechanism drive allowing operation and deactivation of the zone roller of the clutch mechanism preventing operation of the zone roller; and e) a motor control center linking an individual power source to the motor, the motor control center including a transformer to stagger the power source to activate each control module.

11. The system in accordance with the claim 10, characterized in that it further comprises means for driving the motor only when the presence of an article is detected in the plurality of conveyor zones.

12. The system in accordance with the claim 11, wherein the relay for each zone is contained in a housing and each zone solenoid is arranged with each zone clutch mechanism.

13. The system in accordance with the claim 12, characterized in that the relay and the solenoid of each zone are linked through flying connections, the flying connections can be configured on the basis that if the zone is an input power zone, an intermediate zone and a power supply zone. output to determine whether or not there is space to energize the solenoid, the flyer connections are arranged within the housing.