Apparatus for sensing conditions local to a conveyor belt

Abstract

Apparatus and method for sensing conditions local to a modular conveyor belt and wirelessly transmitting signals representing those conditions to an off-belt belt monitoring system. A load cell pin installed in a clevis formed at a hinge joint between adjacent rows of a modular conveyor belt serves as a clevis pin to interconnect the rows and as a sensor sensitive to belt tension transmitted through the clevis. A special load-sensing belt module forms the clevis and holds electronic circuitry that takes the measurements made by the sensor, logs them in a memory element, and transmits them wirelessly to the belt monitoring system. The measurements may also be used as part of a closed-loop control system to control the speed or other operating characteristics of the conveyor system. Furthermore, a variety of sensors housed in sensor modules similar to standard conveyor belt modules may be installed in the belt as drop-in replacements for standard modules.

1 . A modular conveyor belt comprising:
 a series of rows of one or more belt modules hingedly linked together at hinge joints between adjacent rows;   wherein at least one of the belt modules is a load-sensing belt module that includes a load sensor making measurements of belt tension in at least a portion of the load-sensing belt module;   wherein the load-sensing belt module further includes a memory element for storing as a group a series of the measurements of belt tension made by the load sensor.   
   
   
       2 . A modular conveyor belt as in  claim 1  wherein the load-sensing belt module further includes a transmitter to wirelessly transmit signals representative of the measurements of belt tension made by the load sensor. 
   
   
       3 . A modular conveyor belt as in  claim 1  wherein the load-sensing belt module further includes one or more electrical cells to power the load sensor. 
   
   
       4 . A modular conveyor belt as in  claim 2  wherein the load-sensing belt module further includes:
 a cavity housing the memory element and the transmitter; and   a cover over the cavity to retain the memory element and the transmitter.   
   
   
       5 . A modular conveyor belt as in  claim 1  wherein the load-sensing belt module is positioned at an outside edge of the modular conveyor belt. 
   
   
       6 . A modular conveyor belt as in  claim 1  wherein the load-sensing module includes a plurality of laterally spaced apart hinge elements along one end and fewer laterally spaced hinge elements along the other end. 
   
   
       7 . A modular plastic conveyor belt comprising:
 a series of rows of one or more standard belt modules hingedly linked together between adjacent rows;   at least one sensor module including:
 a sensor making measurements of a local condition; 
 a memory element for storing the measurements as a group; and 
 a transmitter for wirelessly transmitting signals representing the group of measurements. 
   
   
   
       8 . A modular plastic conveyor belt as in  claim 7  wherein the at least one sensor module has a cavity in which the memory element and the transmitter are embedded. 
   
   
       9 . A modular plastic conveyor belt as in  claim 7  wherein the sensor is a load cell measuring tension in the modular conveyor belt. 
   
   
       10 . A modular plastic conveyor belt as in  claim 7  wherein the local condition that the sensor measures is selected from the group consisting of temperature, humidity, and belt tension. 
   
   
       11 . A conveyor system comprising:
 a conveyor belt including:
 a sensor making measurements of a local conveyor system condition; 
 a memory element for storing the measurements as a group; and 
 a transmitter for wirelessly transmitting signals representing the group of measurements; 
   a controller using the group of measurements to control the operation of the conveyor system in a closed-loop system.   
   
   
       12 . A conveyor as in  claim 11  wherein the local condition that the sensor measures is selected from the group consisting of temperature, humidity, and belt tension. 
   
   
       13 . A conveyor as in  claim 11  wherein the sensor is a temperature sensor making temperature measurements and wherein the controller provides a signal to control the temperature. 
   
   
       14 . A conveyor as in  claim 11  wherein the sensor is a load sensor making measurements of belt tension and wherein the controller provides a motor-control signal to control the speed of the conveyor belt. 
   
   
       15 . A conveyor as in  claim 11  wherein the conveyor belt is a modular plastic conveyor belt comprising a series of rows of one or more standard belt modules hingedly linked together between adjacent rows and a sensor module disposed in one of the rows and housing the sensor, the memory element, and the transmitter.