Patent Publication Number: US-2003231317-A1

Title: System and device for detecting and separating out of position objects during manufacturing process

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The invention relates to a manufacturing process or other material processing operations, and particularly to apparatus and methods for identifying and separating out-of-position objects which are being conveyed.  
       [0003] 2. Discussion of the Background  
       [0004] In manufacturing and other material processing operation, problems can arise due to defects in the raw materials or unfavorable operational settings in the machines. Such situations can easily move an object being processed out of position, causing a defective product or operational problems. An object which is out-of-position can lead to wasted raw materials, damaged cutting bits or stamping plates, or jammed machinery. Such situations lead to work flow stoppage and often necessitate expensive repairs. Furthermore, if the problem remains undetected for a period of time, defective products will be intermixed with acceptable products, thus increasing spoilage and defect rates, and possibly affecting customer satisfaction.  
       SUMMARY OF THE INVENTION  
       [0005] The present invention has been developed to provide an accurate system for detecting out-of-position objects, allowing non-acceptable objects to be separated from acceptable objects or repositioned for further processing.  
       [0006] The present invention applies to various material processing operations such as manufacturing, production assembly, machine welding, cutting, stamping, canning, bottling, bottlecapping, printing, or other like object conveyance related processes or operations.  
       [0007] One object of the invention is to provide a system for identifying and separating out-of-position objects during a manufacturing process or other material handling operation.  
       [0008] In order to achieve this and other objects, the invention uses a control system device to identify an object which is out-of-position during a conveying step in the material processing operation. An out-of-position object is an object which is not correctly situated, or is improperly oriented (e.g., misaligned) with respect to a reference system being used for the specific material processing system associated with the position detection control system  100 .  
       [0009] In accordance with one embodiment, an object is conveyed on a conveyor belt at a predetermined production speed in a production flow direction. A proximity sensor detects when the object enters an inspection zone and communicates a proximity indication to a position detector. The position detector, which can be embodied as two laser sensors, performs a position detection for the object upon receiving the proximity indication from the proximity sensor. The position sensor returns a signal indicating whether the object is out-of-position and requires further measures such as separation from the conveyor belt or repositioning. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0010] A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:  
     [0011]FIG. 1 is a block diagram of a system for identifying and separating out-of-position objects, according to the present invention;  
     [0012]FIG. 2 is a block diagram depicting locations for exemplary embodiments of the present invention in relation to a typical configuration of a conveyance system and a material processing machine; and  
     [0013]FIG. 3 is a flowchart of a method in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION  
     [0014] In FIG. 1, a block diagram of a system for identifying and separating out-of-position objects, the position detection control system  100  includes one or more laser sensor positioning mechanisms  1 , laser sensors S 2  and S 3 , a proximity sensor S 4 , a programmable logic controller  5  (PLC), a display board  6 , and a buzzer  7 . The control system  100  in the figure is shown configured for use with a conveyor belt  8  and a material processing machine  9 . Although the embodiment depicted in FIG. 1 shows the position detection control system  100  being used with a conveyor belt  8 , the present invention can be used with other type of material conveyance systems as well. For example, the position detection control system  100  typically works in conjunction with a conveyor belt  8  as shown in the figure, or a conveyance system such as a pick-and-place mechanism, a robotic arm, or other like type of material conveyance system known to those of skill in the art. The material processing machine  9  may be any type of machine or device that performs an operation which is position sensitive e.g., a machine for manufacturing, production assembly, printing, cutting, stamping, bottlecapping, canning, welding, or the like. The control system  100  can either be installed permanently to the conveyance system, or can be semi-permanently positioned using removable clamping mechanisms or like types of fastening devices.  
     [0015] Preferred embodiments of the PLC  5  have a special program to process the information received from the sensors. The PLC  5  can be embodied as a computer, a processor, or other type of controller device, logic structure or operational steps. The PLC  5  is typically located proximate the general area of the laser sensors S 2  and S 3  and display board  6 . However, it may be located within an office area of the plant, or even remotely located off-site and configured for remote control of the system. A complicated manufacturing process may have several position detection control systems  100  located at key points along the object&#39;s path. In such systems, a single PLC  5  can be configured to control the various components of several detection control systems  100 .  
     [0016] One object of the position detection control system  100  is the detection of out-of-position objects as the conveyor advances in the production flow direction. To achieve this, the control system  100  includes two different kinds of sensors. The proximity sensor S 4  detects an approaching object which has reached an acceptable position for the inspection, that is, an inspection zone. The inspection zone can be defined as being an area in which position detectors (e.g., laser sensors S 2 -S 4 ) can be used to detect the position of an object. The proximity sensor S 4  can be used to determine if an object has reached the inspection zone. In one embodiment, the maximum detection range of the proximity sensor S 4  determines the far edge of the inspection zone, while the near edge of the inspection zone is determined by how far along the conveyor belt  8  the sensors S 2  and S 3  are able to make a position detection. In alternative embodiments, the proximity sensor S 4  can detect an object which is approaching the inspection zone.  
     [0017] One or more laser sensors, e.g., the pair of laser sensors S 2  and S 3 , detect the position of the object. The laser sensors S 2  and S 3  are preferably mounted on the framework of the conveyor or other part of the conveyance system, next to the material processing system, e.g., manufacturing machine. The laser sensors S 2  and S 3  are located a predetermined distance away from each other. The predetermined mounting distance depends upon the product dimensions, the mounting configuration of sensors S 2 , S 3  and S 4 , and the parameters of the conveyance system. The predetermined distance between lasers S 2  and S 3 , and their orientation with respect to each other can be adjusted for products having different dimensions, sizes or shapes, and for the speed of the conveyance system.  
     [0018] The sensors S 2 -S 4  are preferably located far enough away from the material processing system (e.g., manufacturing machine  9 ) so that an out-of-position object can be dealt with before the conveyance system moves it too far (e.g., into the manufacturing machine). For a conveyance system set to a predetermined conveyance velocity V c , the proximity sensor S 4  is located at least a distance D, away from the processing machine, wherein D s  is determined by the relationship:  
       D   s   =V   c ×( A   t   +P   t )  (1)  
     [0019] In the above relationship, the variable A t  represents the separation time, e.g., the time it takes to separate or reposition an object determined to be out-of-position from the conveyance system. The variable P t  represents position detection time which includes the actual measure of position plus any processing and signal communication time between the components of the position detection control system  100 . For example, P t  includes the time it takes for a proximity indication to be generated and communicated from the proximity sensor S 4  to the laser sensors S 2  and S 3  via the PLC  5 , the time required for a position detection to be executed by the laser sensors S 2  and S 3 , plus any further time required for providing the out-of-position signal back from the laser sensors S 2  and S 3 .  
     [0020] The laser sensors S 2  and S 3  are connected to the PLC  5 , where the sensor signals are monitored, received and analyzed. The PLC  5 , in turn, sends an output signal to the display board  6 . Typically, the connections between the various components of position detection control system  100  are hard-wired signal lines running between the devices. Alternatively, an infrared or other wireless link can be used to interconnect one or more of the components of the position detection control system  100 . The control system  100  can also be interconnected using a common bus, and a timing or addressing scheme.  
     [0021] Upon receiving a signal indicating of an out-of-position object, the display board  6  denotes the defective object&#39;s location within the conveying system. This allows the out-of-position object to be separated or reorientated either manually or through an automatic process. A complicated manufacturing process may have several position detection control systems  100  located at key points along the object&#39;s path. In such embodiments, a single display board  6  can be configured to display the results of the several position detection control systems  100 . The display board  6  can be embodied in various forms, e.g., as a CRT, LCD or other type of display monitor; a one or more arrow keys indicating a direction of misalignment; as an arrangement of light emitting diodes (LEDs); or as an on/off warning light providing only a binary indication of an out-of-position object.  
     [0022] The laser sensors S 2  and S 3  detect the occurrence of an out-of-position object for the specific operation or processing machine associated with the position detection control system  100 . Whether an object is out-of-position or not can be determined with respect to a number of reference systems, points or objects, in accordance with various embodiments of the present invention. For example, an object can be deemed out-of-position relative to the conveyance system, relative to the material processing system, relative to other objects, relative to the system  100 , or relative to an arbitrarily defined coordinate system (e.g., Cartesian coordinates; yaw, pitch and roll; GPS coordinates; or the like).  
     [0023] The sensors S 2 -S 4  are typically located in the proximity of the production flow at the entrance to the material processing machine  9 . Alternatively, the sensors S 2 -S 4  can be located anywhere along the conveyance system. In some situations, it is advantageous to locate the sensors far enough away from the entrance of the material handling machine so that out-of-position objects can be removed or repositioned. One or more of the sensors S 2 -S 4  can be adjusted to accommodate objects of various sizes, or to recalibrate or reorient them to maintain accurate readings. In accordance with some embodiments, the adjustment can be performed using the laser sensor positioning mechanism  1  as illustrated in FIG. 1. The sensor positioning mechanism  1  may be embodied with a stepper motor, a solenoid, a piston mechanism, or other like device for moving or reorienting the sensors. In a preferred embodiment, this can either be done using one laser sensor positioning mechanism  1  for each of the sensors S 2  and S 3 , and, in some embodiments, the sensor S 4 . Alternatively, the adjustment can be performed by having only one of the sensors S 2  and S 3  equipped with a laser sensor positioning mechanism  1 . That is, some of the sensors can be equipped with positioning mechanisms  1  while others are not.  
     [0024] During operation of the position detection control system  100 , the proximity sensor S 4  provides a proximity indication signifying that the object is in the appropriate inspection zone. The proximity indication is communicated to the laser sensors S 2  and S 3  which in turn initiate a position detection. In practice, a detection by the proximity sensor S 4  can be communicated to the PLC  5 , which, in turn, communicates an indication of object proximity to the laser sensors S 2  and S 3 . As illustrated on the FIG. 1, objects advance in a continues process in the flow production direction, as the sensors S 3  and S 4  detect out-of-position objects. In a preferred embodiment, the PLC  5  uses a program developed for this invention to verify the signals (inputs) from laser sensors S 2  and S 3 , and sends output signals to the display board  6 .  
     [0025] The buzzer  7  can also be provided to indicate an objected detected to be out-of position. Upon detecting an out-of-position object with the laser sensors S 2  and S 3 , the buzzer  7  turns ON, and turn OFF after the defective product has been separated from the conveyance system, or otherwise ameliorated (e.g., reoriented, repositioned, or otherwise corrected). The step of separating the object can comprise a step of temporarily slowing down the conveyance system until the out-of-position object has been dealt with. Regarding the buzzer  7 , in an alternative embodiment the buzzer  7  is turned OFF after a predetermined amount of time regardless of whether the out-of-position object has been separated or not.  
     [0026]FIG. 2 is a block diagram depicting locations for exemplary embodiments of the present invention in relation to a typical configuration of a conveyance system and a material processing machine. One of ordinary skill in the art would know to alter the relative positioning of the components of the present invention to conform to the parameters and requirements of the conveyance system and the manufacturing process being performed. The conveyance system of FIG. 2 is depicted in the form of a conveyor belt  8  which moves from right to left, as shown in the figure.  
     [0027] In FIG. 2, the boxes M 2 -M 4  represent machines or other object processing devices located along a conveyor belt C 1  which carry out various material processing or conveyancing operations (e.g., manufacturing, production assembly, object handling, or the like). In one exemplary embodiment in which FIG. 2 depicts a bottling process, M 1  and M 2  represent label printing machines for printing two different colors of the bottle label, M 3  represents a varnish oven for applying varnish and applying heat to dry it, and M 4  represents a bottle stacker machine.  
     [0028] The sensors S 2 -S 4  according to the present invention can be configured at a number of different locations along the conveyor belt C 1 , depending upon the physical constraints and special requirements of the particular material processing system. In some exemplary embodiments, the sensors S 2 -S 4  can be located proximate the conveyor belt C 1  prior to the printing machine M 2 , as shown in FIG. 2. The configuration shown in the figure, with the sensors S 2 -S 4  located along conveyor belt C 1  before printing machine Ml, is particularly suitable when the conveyor belt C 1  travels at a relatively high speed. A conveyor belt operating at high transfer velocities may necessitate a certain amount of distance between the sensors S 2 -S 4  of the present invention and the stacker machine M 4  in order to reposition or remove an out-of-position object. Further regarding the configuration shown in FIG. 2, even if the transfer velocity of conveyor belt C 1  is not a concern, it may be desirable to locate sensors S 2 -S 4  prior to printing machines M 1  and M 2  and varnish oven M 3  simply as a matter of convenience (e.g., if there is ample room for the sensors) so long as the printing machines M 1  and M 2  and varnish oven M 3  do not cause problems with misalignment. In FIG. 2, the proximity distance D s  is the distance which the proximity sensor S 4  is located away from the processing machine M 4 .  
     [0029] The physical constraints and special requirements of the material processing system may make it desirable to locate sensors S 2 -S 4  in an alternative embodiment configuration to that shown in FIG. 2. For example, in some factory settings it may be that the bottle stacker machine M 4  requires the bottles to be correctly aligned to prevent an unacceptably high percentage of errors from occurring when the bottles are stacked (e.g., to prevent bottle breakage, bottles tipping over). In a system in which the varnish oven M 3  tends to cause bottles to be out of position, it is preferred to locate the present invention at a point past the varnish oven M 3 , but before the stacker machine M 4 . In other instances, the system may be such that the label printing machines M 1  and M 2  sometimes cause bottles to become misaligned, but the varnish oven M 3  does not cause misalignment. In these instances, the location between label printing machine M 2  and varnish oven M 3  may prove to be the best choice of location for the present invention. In addition to the aforementioned locations for the sensors S 2 -S 4 , those of ordinary skill in the art would know to locate the sensors at other locations along the conveyor belt C 1  in order to better adapt the present invention to the physical constraints and special requirements of the material processing system being used.  
     [0030]FIG. 3 is a flowchart of a method in accordance with the present invention. The method begins at step S 100  and proceeds to step S 102  where the object is conveyed. For purposes of explanation, the present invention is discussed in terms of a conveyor belt being used to move the object. However, the object may be conveyed using any of a number of different types of conveyance systems, in accordance with the invention. The method proceeds from step S 102  to step S 104  where it is determined whether the object being conveyed is in the inspection zone. This is done by using one or more proximity sensors to determine whether the object being conveyed has reached the inspection zone. If an object has not yet reached the inspection zone, the method proceeds in accordance with the “NO” branch from step S 104  back to step S 102 . When it is determined, e.g., by a proximity sensor, that the object is within the inspection zone, the method proceeds from step S 104  in accordance with the “YES” branch to step S 106 .  
     [0031] In step S 106  the proximity sensor communicates to the position detection control system that the object being conveyed is within the inspection zone. The communication may take place either wirelessly or via hard-wired signal lines running between the devices. The proximity sensor typically communicates a proximity indication to the programmed logic controller of the system, which in turn communicates the appropriate signals to other components of the system. For example, upon receiving a proximity indication from the proximity sensor, the programmed logic controller sends the appropriate signals to the sensors involved in position detection. In alternative embodiments, the proximity sensor can communicate a proximity indication directly to various components within the system, e.g., the laser position sensors. Upon completing step S 106 , the method proceeds to step S 108 .  
     [0032] In step S 108  sensors are used to make a position detection. In preferred embodiments, laser sensors are used to detect the position of the object being conveyed upon receiving a signal indicating that the object is in the inspection zone. Once the position detection has been performed in step S 108 , the method proceeds to step S 110  where it is determined whether the object is out of position or not.  
     [0033] If the object is out of position the method proceeds in accordance with the “NO” branch from step S 11  to step S 116 . If in step S 110  the object is determined to be out of position, the method proceeds in accordance with the “YES” branch from step S 110  to step S 18 . In step S 108  the out of position object is manipulated in a predetermined manner consistent with the manufacturing operation or other material processing operation being performed. For example, in some processes it may be appropriate simply to remove the out of position object from the conveyor belt. In other processes, it may be appropriate to reposition the object for further processing along the conveyor belt. While yet in other processes, it may be appropriate to reposition the object so that it is within the desired position for further processing on the conveyor belt. Upon the completion of step S 108 , the method proceeds to step S 116  where it is determined whether there is another object being conveyed and the method is to be performed on that object.  
     [0034] If, in step S 116 , it is determined that there is another object, the method proceeds in accordance with the “YES” branch from step S 116  to step S 118 . Then, as the next object moves along the conveyor belt the method loops around from step S 118  back to step S 102  to handle the next object. However, if in step S 116  it is determined that there is not another object to be handled, the method proceeds in accordance with the “NO” branch from step S 116  to step S 120 , where the method ends.  
     [0035] To facilitate an understanding of the invention, many aspects of the invention have been described herein in terms of sequences of actions to be performed by elements of a computer system. It will be recognized that in each of these embodiments, the various actions could be performed by specialized circuits (e.g., discrete logic gates interconnected to perform a specialized function), by program instructions being executed by one or more processors or other such processing devices, or by a combination of these. Moreover, the invention can be embodied entirely within any form of computer readable storage medium having stored thereon an appropriate set of computer instructions that would cause a processing device to carry out the method described herein. Thus, the various aspects of the present invention can be embodied in many different forms, and all such forms are contemplated to be within the scope of the invention.  
     [0036] Although a number of embodiments are described herein for purposes of illustration, these embodiments are not meant to be limiting. Those of skill in the art will recognize numerous modifications and variations that can be made to the illustrated embodiments of the present invention, in light of the above teachings. Such modifications and variations are meant to be covered. It is therefore to be understood that within the invention may be practiced otherwise than as specifically described in conjunction with the illustrative embodiments herein. The scope of the claimed invention is defined by the appended claims, rather than the illustrative embodiments provided herein.