Patent Number: 046684662
Section: abstract

A grid cell spring force measuring apparatus includes a pair of elongated bars being pivotally connected together at their respective mid-sections and having a set screw for presetting the displacement between the lower end portions of the bars and a rotatable shaft with a knob for applying a separation force to the upper end portions of the bars. When the displacement of the bars and thereby their cross sectional dimension is preset and the bars have been inserted into a grid cell, the shaft is rotated using the knob and the upper end portions of the bars are gradually forced apart. Once the force being applied at the upper end portions and transmitted to the lower end portions of the bars overcomes the spring force, the spring deflects and the bars separate enough to open electrical contacts mounted on the bars. At the instance the contacts are opened, a readout connected to a strain gauge fixed on one of the bars records the level of force being imposed by the bar on the cell spring.