Position: A third embodiment of the present invention is illustrated in FIGS. 5 and 6. The belt scale indicator 170 includes a weight sensor support 172, a cell 30 identical to the load cell illustrated in FIGS. 1-4, and an idler support 174. Load cell support 172 includes a top 176 and side flanges 178 extending downwardly from top 176. cell 30 is coupled to top 176 of cell support 172 by bolts 180 and nuts 182. A shim 184 is located between weight sensor 30 and top 176 of load cell support 172 at each end of cell 30 so that the bottom surface 50 of cell 30 is spaced apart from top 176 of load cell support 172. This permits deflection or bending of cell 30. Shims 184 are made from a material that is insensitive to temperature changes and does not expand or contract substantially over a wide range of temperatures. Therefore, the position of weight sensor 30 relative to load cell support 172 does not change substantially as the temperature changes. Accordingly, the position of idler support 174 remains substantially level with upstream and downstream idler stations despite temperature fluctuations.
Idler support 174 includes a top 186 and downwardly extending side flanges 188. Threaded fasteners 190 extend through apertures 192 formed in top 186 and into threaded apertures 46 of cell 30 to couple idler support 176 to cell 30. Therefore, a bottom surface 193 of idler support 174 abuts contact surface 39 of cell 30.
Coupler plates 194 and 195 are provided to couple belt scale indicator 170 to first and second sides 196 and 198 of a conveyor frame. belt scale indicator 170 is especially useful in situations in which first side 196 of convey or frame is positioned at a level different from second side 198 of conveyor frame. In FIG. 5, horizontal flange 197 of first side 196 is located at a first level illustrated by L1 and horizontal flange 199 of second side 198 of conveyor frame is situated at a second level illustrated by level L2. Coupler plate 194 is coupled to horizontal flange 197 by bolts 200 and nuts 202. Coupler plate 195 is coupled to horizontal flange 199 by bolts 204 and nuts 206. Coupler plates 194 and 195 are coupled to opposite ends of cell support 172 by bolts 208 and nuts 210. A spacer plate 212 is situated between coupler plates 194 and 195 and top 176 of weight sensor support 72 at each end of load cell support 172.
It is desirable that the load cell idler station is aligned with idler assemblies or stations both upstream and downstream from the load cell idler station on conveyor frame. An unlevel load cell idler station can cause cell 30 to generate inaccurate output signals. belt scale indicator 170 includes six shim areas which permit the level of weight sensor 30 to be adjusted. Shim areas are located between coupler plate 194 and horizontal flange 197 of first side 196 of the conveyor frame, between spacer plate 212 and coupler plates 194 and 195 at each end of load cell support 172, between top surface 176 and spacer plate 212 at each end of load cell support 172, and between coupler plate 195 and horizontal flange 199 of second side 198 of the conveyor frame. A shim can be placed in any of these six shim areas to adjust the position of cell support 172 and cell 30 relative to the conveyor frame. In the FIG. 5 illustration, horizontal flange 197 is located at a first level L1 which is lower than the level L2 of second horizontal flange 199. Therefore, a shim 214 is positioned between coupler plate 194 and horizontal flange 197 to elevate the position of coupler plate 194 and the end of load cell support 172 adjacent first side 196 of the conveyor frame. In addition, a shim 216 is positioned between coupler plate 195 and spacer plate 212 adjacent second side 198 of the conveyor frame. This lowers the end of weight sensor support 172 adjacent second side 198 of the conveyor frame. By adding shims 214 and 216, contact surface 39 of cell 30 is substantially level, despite the different levels of horizontal flanges 197 and 199. If necessary, an additional shim (not shown) can be added between spacer plate 212 and top 176 of load cell support 172 adjacent second side 198 to lower the end of load cell support 172 adjacent second side 198 further.
If first horizontal flange 197 is at a higher level than second horizontal flange 199, a shim would be added between coupler plate 195 and horizontal flange 199 to raise the level of cell support 172 adjacent second end 198. In addition, shims could be added between coupler plate 194 and spacer plate 212 and between spacer plate 212 and top 176 of load cell support 172 adjacent first side 196. This would lower the end of weight sensor support 172 adjacent first side 196 of the conveyor frame to level contact surface 38 of cell 30.
An idler roller assembly such as assembly 14 illustrated in FIG. 1 is coupled to idler support 174 by threaded studs (not shown) welded to top 186 of idler support 174. When material moves on a conveyor belt over idler roller assembly, idler support 174 applies a force in the direction of arrow 218 on cell 30. Because cell 30 is spaced apart from top 176 of load cell support 172 by shims 184, the force in the direction of arrow 218 causes deflection of base 36 of cell 30. This deflection causes the resistance of strain gauges 52 to change which, in turn, causes an output signal from weight sensor 30 to change in proportion to the weight of the material passing over the idler roller assembly above idler support 174 as discussed in detail with reference to FIGS. 1-3.
It is understood that the various components of the three illustrated embodiments may be interchanged if desired. For example, the adjustment coupling weighing indicators and weighing controllers illustrated in FIG. 5 could be used in either of the first two embodiments.
Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims.