Abstract:
A conveyor belt ( 10 ) contains at least one integrated circuit transponder ( 30 ) which, upon interrogation by an external radio signal, transmits identification information in digitally encoded form. The transponder ( 30 ) has a generally planar, circular antenna ( 36 A) surrounding a printed circuit board to which an integrated circuit is attached. The transponder may be encased in a rigid epoxy material to protect the structure from damage during use. Transponders placed adjacent splices ( 60, 62, 64 ) in a splice segment provide non-contact means of locating and monitoring the repair.

Description:
TECHNICAL FIELD 
     This invention pertains generally to the art of conveyor belt identification means and more specifically to the use of an embedded integrated circuit transponder which is interrogated to transmit belt identification and other data. 
     1. Background Art 
     In the manufacture of conveyor belts it is desirable to provide unique identification for each belt, A currently used procedure molds an alphanumeric “brand” onto the belt surface. The brand normally identifies the belt type, the date of manufacture and the belt section. In addition, at times splices are needed to repair damaged segments of a conveyor belt. It is also convenient to brand the spliced segments so as to monitor the success of the repair effort. With prior art devices, the information contained on the brand is readable only while the belt is nonoperative and relatively free from excess debris 
     In the art it is known that monitoring the condition of an endless conveyor belt during usage can prevent irreparable belt damage and needless production delays. The presence of rip detection coils embedded within the layers of a conveyor belt is one tool used for such monitoring. For the most part, the embedded devices are passive antennae which serve as coupling devices when specific sections of the belt pass by a rip detection station. Generally, an electrical current is induced in an antenna, and if a sufficiently strong signal is received from the antenna, it is presumed that the integrity of the belt is maintained. An insufficiently transmitted signal, on the other hand, may indicate the presence of a longitudinal rip in the belt surface requiring immediate attention. 
     The present invention relates to an endless conveyor belt having an integrated circuit transponder embedded within the structure of the conveyor belt for use in belt or belt section identification. The transponder is a passive device which depends upon the receipt of an interrogation signal emanating from an outside source. The interrogation signal is rectified by the integrated circuit transponder, which then transmits an electrical signal digitally encoded to identify the belt or belt section. A unique “digital brand” can be used for each belt or belt section. 
     The present invention provides a non-contact means for identifying a conveyor belt, or belt section, and monitoring thereof which is simple and efficient while providing better and more advantageous results. 
     2. Disclosure of Invention 
     According to another aspect of the invention, an endless conveyor belt having an elastomeric body, a top cover, a pulley cover, and a reinforced layer disposed between and coextensive with the top cover and the pulley cover, 
     a splice in the top cover, a splice in the pulley cover, and a first splice in the reinforced layer due to a splice in the belt is characterized by: 
     a first integrated circuit transponder being located in the reinforced layer in close proximity to the first splice for use in splice identification and monitoring. 
     According to another aspect of the invention, the conveyor belt further comprises a second integrated circuit transponder which is positioned with the pulley cover near the periphery of the pulley cover and the reinforced layer. 
     According to another aspect of the invention, the first transponder comprises an antenna comprising an electrical coil having a plurality of bunched turns, the coil being substantially planar, the plane of the coil being substantially parallel with the belt surfaces; and, a printed circuit board attached to the coil, the integrated circuit of the first transponder being mounted on the circuit board. 
     According to another aspect of the invention, a method of locating a splice in a conveyor belt comprises the steps of: 
     embedding an integrated circuit transponder in the structure of the conveyor belt near the splice, the transponder being able to transmit an electrical signal in response to an oscillating electric or magnetic field emanating from a source in contact with or spaced from the belt; 
     interrogating the transponder with the oscillating electric or magnetic field; and, 
     receiving the transmitted electrical signal from the transponder. 
     According to another aspect of the invention, a conveyor belt identification system comprises: 
     a transducer embedded within the belt structure, the transducer being encoded with predetermined identification data, the transducer being able to transmit the data in response to an oscillating electric or magnetic field emanating from a source in contact with or spaced from the belt; and, 
     means for receiving the transmitted identification data. 
     According to another aspect of the invention, a method of locating a splice in a conveyor belt is characterized by the steps of embedding an integrated circuit transponder in the structure of the conveyor belt near the splice, the transponder being able to transmit an electrical signal in response to an oscillating electric or magnetic field emanating from a source in contact with or spaced from the belt; interrogating the transponder with the oscillating electric or magnetic field, and receiving the transmitted electrical signal from the transponder. 
     One advantage of the present invention is the provision of non-contact means for identifying a conveyor belt or belt section. 
     Another advantage of the present invention is the provision of a quick and precise method of monitoring a repair in a conveyor belt. 
     Still other benefits and advantages of the invention will become apparent to those skilled in the art upon a reading and understanding of the following specification. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     The invention may take physical form in certain parts and arrangement of parts. A preferred embodiment of these parts will be discussed in detail in the specification and illustrated in the accompanying drawings, which form a part of this disclosure and wherein: 
     FIG. 1 is a perspective view, partly in section, of a conveyor belt having an embedded integrated circuit transponder according to the invention. 
     FIG. 2 is a perspective view of one embodiment of a transponder according to the invention. 
     FIG. 3 is a perspective view of another embodiment of a transponder according to the invention. 
     FIG. 4 is a transverse sectional view of a conveyor belt having a steel cable reinforced layer and two embedded transponders. 
     FIG. 5 is a side view of a splice in a reinforced conveyor belt having embedded transponders according to the invention. 
     FIG. 6 is transverse sectional view of a textile belt having embedded transponders. 
     FIG. 7 is a side view of a splice in a textile belt having embedded transponders according to the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 is directed to a conveyor belt  10  comprising an elastomeric body  12  having a top cover  14 , which includes a load-carrying surface  16 , and a parallel pulley cover  18 , which has a pulley-engaging surface  20 . The conveyor belt also has at least one reinforced layer  22  disposed within the elastomeric body  12 . 
     In a preferred embodiment, the reinforced layer  22  includes steel cables  24 , although the present invention may be practiced in many types of reinforced conveyor belts including those reinforced with fabric, such as nylon, rayon, cotton, polyester, aramid, and others. 
     In accordance with the invention, one or more integrated circuit transponders  30  are embedded within the structure of the conveyor belt  10 . The need to protect the embedded transponders  30  from the severe conditions of the belt&#39;s working environment and while simultaneously providing convenient access to the transponder  30  will determine the placement in a belt. One or more transponders  30  may be placed at predetermined positions along the length of the belt to indicate the presence of splices, rip detection coils, brand site and the like. In the art, it is usual to place a brand  34  on an edge of the conveyor belt  10 . The brand  34  may be alphanumeric and normally contain information corresponding to the belt&#39;s manufacturing date, materials of construction used in the belt, equipment intended to be used with the belt, and the like. FIG. 1 shows an embedded integrated circuit transponder  30  located in the top cover  14  near the brand  34 . Such a transponder  30  may emit data relating to the brand  34  upon interrogation. 
     With particular reference to FIGS. 2 and 3, the detailed structure of the embedded transponder  30  will be described. A preferred embodiment of the invention, shown in FIG. 2, utilizes a transponder  30 A which is of a flat-ring style made of an electrical coil which is wound in a generally flat plane which serves as the antenna  36 A. The number of windings of the transponder is a matter of engineering judgment depending on the application. The ring is preferably 1.5 mm to 2.0 mm thick and has an outer diameter D 1  of between 45 mm and 60 mm and an inner diameter D 2  of between 40 mm and 55 mm. However, coil length, width, turns and other characteristics may be varied according to the particular requirements of each application. The transponder  30 A is embedded in the belt structure in a plane generally parallel with the belt surfaces  16 ,  20 . 
     Attached to this antenna  36 A is a printed circuit board  40 A. The RF-ID integrated circuit  42 A, hereinafter IC, is mounted onto the circuit board  40 A. The IC  42 A and board  40 A are encased in a rigid epoxy material, such as is available from the Dexter Hysol Corporation under the trade name “Dexter Hyso 4322”, while the antenna  36 A itself is coated with a soft polymeric material, such as solderable polyester to NEMA standard MW-77-C. The preferred IC board  40 A is approximately 8 mm square. The preferred antenna is presently manufactured from coated wire. 
     Another embodiment of the invention, shown in FIG. 3, utilizes a transponder  30 B wherein both the IC board  40 B and the antenna  36 B are encapsulated with a rigid epoxy material, such as is available from the Dexter Hysol Corporation under the trade name “Dexter Hysol 4322.” In this embodiment, the flat ring antenna  36 B consists of an electrical coil wire wound in a flat plane having a thickness of from 1.5 mm to 2.0 mm with an outer diameter D 4  of about 15 mm to 25 mm and an inner diameter D 3  of about 8 mm to 18 mm. The IC board  40 B is located in the center of the ring. 
     Both embodiments of the transponder  30 A,  30 B herein described are adhered to the rubber of the belt covers  14 ,  18 , or to the rubber covering the reinforcement. A suitable epoxy or other adhesive, such as an adhesive available from the Lord Corporation under the trade name Chemloc 205, is used to prevent any possibility of a static charge arising from the transponder  30  due to rubber movement. 
     The function of the transponder  30  is similar to that which is disclosed in U.S. Pat. No. 5,181,975, the entire disclosure being incorporated herein by reference. An emitted RF signal is received by the transponder  30 . The transponder  30  is powered by the signal and in turn emits a return RF signal which carries a data stream. 
     In one embodiment, the interrogation signal is provided via a hand held reader (not shown), The reader also acts as the receiver for the return RF signal. Alternately, the RF reader could be placed at some fixed location along a conveyor system. In a preferred embodiment, the input signal from the reader is at 125 KHz and the return signal is at 62.5 KHz. 
     FIG. 4 shows a preferred embodiment of the invention utilizing a conveyor belt  10  having a steel cable-reinforced layer  22 . Two transponders  30  are positioned within the belt  10 . A first transponder  30 C is located within the top cover  14  on the interface between the top cover  14  and the reinforced layer  22 . A second transponder  30 D is located on the interface between the pulley cover  18  and the reinforced layer  22 . This configuration is advantageous because the first transponder  30 C is protected from the load-carrying surface  16  and the second transponder  30 D is protected from the pulley-engaging surface  20 . 
     FIG. 5 shows where the transponders  30  could be located in the event that the conveyor belt  10  contains a splice  44 . A first transponder  30 E is located in the reinforced layer  22  near a splice  44  therein. A second transponder  30 F is embedded between the top cover  14  and the reinforced layer  22 , near a splice  46  in the top cover  14 . A third transponder  30 G is located between the pulley cover  18  and the reinforced layer  22  near a splice  48  in the pulley cover  18 . Upon interrogation, each of the transponders  30  is capable of emitting digitized data such as date of splice installation and type of material used in making the splice. By marking each splice  44 ,  46 ,  48 , interrogation of the transponders  30  would provide immediate location and identification of the splice to permit monitoring of the repair. The transponders  30  are capable of being encoded with appropriate data such as date of installation, belt material utilized, and the like. 
     FIG. 6 shows another preferred embodiment of the invention utilizing a conveyor belt  10  having a fabric-reinforced layer  22 . In the figure, the conveyor belt  10  again comprises a top cover  14  and a pulley cover  18 . The reinforced layer  22  consists of three fabric plies  50 ,  52 ,  54 , although other configurations are possible. In a preferred embodiment, one transponder  30 H is located between the top cover  14  and the uppermost fabric ply  50 . A second transponder  301  is located between the uppermost ply  50  and the middle ply  52 . Alternately, the second transponder  301  could be located between the middle ply  52  and the lowermost ply  54 . A third transponder  303  is located between the lowermost ply  54  and the pulley cover  18 . The widthwise placement of the transponders  30  H,I,J is variable depending on the needs of the application. 
     FIG. 7 shows a preferred embodiment of the invention in a fabric-reinforced conveyor belt  10  which contains a splice. In a typical splice, the splices in each ply of the reinforced layer  22  are staggered along the length of the belt. For example, the splice  60  for the uppermost ply  50  is offset some length L 1  from the splice  62  in the middle ply  52  which is itself offset some length L 2  from the splice  64  in the lowermost ply  54 . The splices  60 ,  62 ,  64  in the reinforced layer  22  are contained within segments of both the top cover  14  and pulley cover  18  which are spliced into the original belt. The positioning of transponders  30  within the spliced section will give precise locations for each of the splices  60 ,  62 ,  64  in the reinforced layer  22 . A first transponder  30 K is located between the top cover  14  and the uppermost ply  50  in close proximity to the splice  60  of the uppermost ply  50 . A second transponder  30 L is positioned between the uppermost ply  50  and the middle ply  52  (or between the middle ply  52  and the lowermost ply  54 ) in close proximity to the splice  62  of the middle ply  52 . A third transponder  30 M is positioned between the lowermost ply  54  and the pulley cover  18  in close proximity to the splice  64  in the lowermost ply  54 . Again, the widthwise placement of the transponders  30  is variable. 
     The transponders  30  may be embedded in the belt structure during the belt manufacturing process, or added to a surface of a belt layer during a post-cure operation. 
     The present invention has been described with reference to the preferred embodiment. Obviously, modifications and alterations will occur to others upon a reading and understanding of the specification. It is intended by the applicant to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.