Standard Load Cell Installation Instructions

Standard Load Cell Installation Instructions

Best performance of the Load Cell^® is achieved through adherence to the following provisions and instructions. (See specification drawing below)

A. Installation:

1. The support for the load cell must be rigid (at least two or three times the rigidity of the cell) and have a flat and parallel surface to within 0.001 inches TIR, and a recommended surface finish of 63 micro-inches and minimum hardness of Rockwell B-100.
2. The diaphragm side of the load cell must be against the supporting structure.
3. Load to the Universal Load Cell is applied through the threaded hole at the center of the load cell. All the threads in the load cell must be engaged by the loading member. For a through hole installation the loading rod must be torqued to the required levels.
4. Load to the Compression Load Cell is applied to the center raised loading boss. The entire surface of the boss must be engaged by the loading member.

B. Hold-Down Bolts:

Torque values tabulated on the specification table below should be used, in conjunction with Load Cells^®, as follows:

1. Universal and Fatigue rated Load Cell^® Hold-Down Bolts must always be preloaded to specified torque values, regardless of magnitude or type of applied load, in order to repeat and maintain orginal calibration performance of the load cell. The hold-down bolts must be a minimum of 150,000 psi UTS, and seating torque must be applied gradually and uniformly to all bolts, in increments of no more than 1/4 of the final torque value.
2. Compression Load Cell^® Hold-Down Bolts are intended only for assembly location of the cell, and have no effect on calibration. Recommended torque values are not mandatory. In some applications, such as checking the forces generated in hydraulic presses, hold-down bolts may be omitted.
3. Spacers are recommended for use with hold-down bolts, see the below specification drawing for details. The purpose of the spacers is to prevent loosening of the hold-down bolts, by allowing use of a longer bolt, as well as to provide some additional deflection themselves.

Specifications

C. Loading Bolt:

Loading Bolt preload requirements may be modified according to the following conditions:

1. Uni-Directional, Low Cycle, Low Frequency*, or Static Loading Conditions do not require any preloading.
2. In all modes of loading, other than (1.) above, loading bolt torque values apply. (See specification tables above).
3. For Load Cells^® with through loading holes (without threads), above detailed preloading conditions must be simulated.

*Approximately 1-Hz, depending on masses involved and magnitude of inertia forces generated.

NOTE: “Flat Load Cell”: is a registered trade mark.