Position: In this page, you will learn that the Load cell weight sensor live idler platform scale has an idler to support a conveyor belt and a frame on which the rollers are mounted.
The weighbridge has four load cells connected perpendicular to each end of the frame, strain gauges to receive deflections from each pair of load cells, a speed detector for the material passing upon the conveyor, and a scale controller for converting the signals of the strain gauges and the speed detector to the desired weight and volume data along with calibrating the scale. Beneath the idler, the scale has a calibration weight resting in a tray. Two cables, attached to the idler and its mounts, suspend the calibration weight and an activator raises and lowers the calibration weight. The calibration weight and activator are generally cylindrical and parallel to the longitudinal axis of the idler. (end of abstract)
CROSS REFERENCE TO RELATED APPLICATION
[1] This is a non-provisional application which claims priority to the provisional application Ser. No. 60/722,318 filed Sep. 30, 2005 and commonly owned by the same inventor. The above noted application is incorporated herein by reference. This patent application is related to U.S. Pat. No. 5,338,901 which issued on Aug. 16, 1994, for a Conveyor Belt Weigher Incorporating Two End Located Parallel Beam Load Cells and has the same inventor and assignee.
BACKGROUND OF THE INVENTION
[2] The Load cell weight sensor live idler platform scale relates generally to weighing devices for bulk product. More specifically, the present invention refers to conveyor belt scales of the weighbridge type, used for weighing material as it is transported along a conveyor belt. A unique aspect of the present invention is a calibration weight that temporarily loads an idler with a known weight for calibrating the load cells.
[3] For decades, mines, quarries, foundries, mills, and the like have moved bulk product by conveyor from one location to another. A conveyor also moves product between one stage in a process to another. Each stage in a process likely calls for the weight of product entering the process weighing. Conveyor belt scales are used for continuous weighing of bulk materials transported along the conveyor belt. Examples of such materials are coal, aggregate, slag, or wood chips among others. Knowing the weight allows for adjusting a process and results in an end product within tolerances.
[4] In general, conveyor belt scales with weight controllers employ rollers or idlers that are inserted into the conveyor system, either in place of an existing idler assembly or in addition to the existing idlers. The conveyor belt rests on the idlers and the material, coal for example, passes over the idler assembly causing a downward deflection of the system. Generally, the idler assembly is cooperatively connected to a weight sensor. The weight sensor, depending upon the construction of the particular weighing device, converts the downward deflection into a weight measurement. Ideally, a weighing device would combine the weight with a determination of the speed of the moving conveyor belt to yield a rate of flow of material as well as the total weight of the passing material.
[5] The current invention provides an idler having weight measuring load cells and optionally a speed sensor, controller, and a junction box for multiple units. The present invention displays to an operator an accurate reading of the amount of product crossing the invention within a given time interval. Further, the present invention calibrates the weight measurement upon command using a weight connected beneath the idler.
DESCRIPTION OF THE PRIOR ART
[6] Bulk product companies of many descriptions and operators have developed various means and methods for weighing bulk product when moving upon a conveyor. For instance, U.S. Pat. No. 5,338,901 to the same inventor, weighs the conveyor belt passing upon an idler and imposing a load upon two sensors. The sensors detect deflection in the idler and transmit a signal to a controller that converts the signal into a weight. However, in time the loaded conveyor belt can alter the sensors from true readings of the weight passing over an idler.
[7] Regarding other patents, a typical weighing device of this type is disclosed in U.S. Pat No. 4,682,664 to Kemp. However, this invention has several disadvantages. For example, this design mounts between conveyor frame members and therefore has limited placement. Installation is more difficult and time consuming. Also, this type of device employs two Load cell weight sensors designed for platform weighing. The load cells are mounted under a modified idler and receive the load force at a single point. The force generated by the radial movement of this idler (torsional force) is transmitted to the load cells and is seen as a weight of the same magnitude as the material being weighed. For example, a portion of the torsional movement of the idler is sensed as a downward motion on the weighing apparatus and the torsional movement therefore interferes or adds to the actual weight of the passing material and can give inaccurate weight determinations.
[8] The present invention though overcomes the limitations of the prior art where a need exists to verify weight readings from time to time. That is, the art of the present invention, a Load cell weight sensor live idler platform scale, calibrates the load cells upon command using a weight incorporated into the scale.
SUMMARY OF THE INVENTION
[9] The loadcell live idler platform scale starts as a conveyor belt weighbridge having idlers to support a conveyor belt frame on which the roller idlers are mounted. The weighbridge can also be mounted above the conveyor belt system and has four load cells connected in pairs perpendicular to each end of the frame. Beneath the idler the present invention has a calibration weight resting in a storage frame.
[10] Additionally, the Load cell weight sensor live idler platform scale has two cables that suspend the calibration weight and an activator that raises and lowers the calibration weight. The calibration weight and activator are generally cylindrical in shape and parallel to the longitudinal axis of the idler. The invention also has strain gauges disposed to receive deflections from each pair of load cells as the material passes across the weighbridge; a speed detector to determine the speed of the material passing over on the conveyor, where the detector is of the encoder or speed wheel types; and, a programmable controller for converting the information supplied by the strain gauges and speed detector to the desired weight and volume data.
[11] Therefore, it is an object of the invention to provide a new and improved loadcell live idler platform scale.
[12] It is another object of the invention to provide a weighbridge device that incorporates four load cells equally spaced upon both ends of the idler to obtain an accurate total measurement of the weight of the passing material across the weighbridge, unlike the prior art which must extrapolate from a single measurement of weight.
[13] It is still another object of the invention to provide a mechanism to calibrate the Load cell weight sensors and the controller against a known weight for adjustment of the invention from time to time.
[14] It is still another object of the invention to provide a weighbridge device that can determine torsional movement or radial torque as a positive force on the downstream side and a negative force on the upstream side of the conveyor travel and cancel them out of the weight determination upon summation of the forces.
[15] Yet another object of the present invention is to provide a weighbridge device that can measure the speed of movement of the material across the device and compare it with the weight of the material and thus measure the rate of flow of the material.
[16] A further object of the present invention is to provide a weighbridge device that incorporates a programmable controller than can integrate the weight of material and speed of material passing over the weighbridge and convert that information into a digital readout of accurate weight and volume of material passing over the weighbridge.
[17] Another object of the present invention is to provide a weighbridge device that mounts above the conveyor frame so that the device can be easily and conveniently mounted.
[18] Another object of the invention is to provide a weighbridge device that is easy to assembly, durable, accurate, and well suited for the purpose intended.
[19] These and other objects may become more apparent to those skilled in the art upon review of the invention as described herein, and upon undertaking a study of the description of its preferred embodiment, when viewed in conjunction with the drawings.
