Weight indication and weight indication storage mechanism for a scale

Claim 1

A weight indication and weight indication storage mechanism for a scale comprising a platform, a support for the platform and a central column supporting the platform on the support, the support including deformable parts and deformation of the support parts under a payload placed on the platform delivering a measuring signal corresponding to the weight of the payload, the mechanism including 1. a bridge circuit having four branches, a. a first bridge circuit branch comprising a plurality of series-connected strain gages responsive to the deformation of a first set of the support parts, b. a second bridge circuit branch comprising another plurality of series-connected strain gages responsive to the deformation of a second set of the support parts, and c. a third and fourth bridge circuit branch comprised of a plurality of resistances connected in parallel, each of the resistances having a sliding tap, one of the ends of the first and second bridge circuit branches forming a junction and the other end of the first and second bridge circuit branches being connected to respective ends of the third and fourth bridge circuit branches, 2. a signal amplifier having two input terminals and a signal output, a. a circuit connection between each of the sliding taps and a first input terminal of the amplifier, b. a switch element in each of the circuit connections, and c. a circuit connection between the junction of the first and second bridge circuit branches and a second input terminal of the amplifier, 3. a motor connected to the signal output of the amplifier and operated by the output signal therefrom, 4. drive means comprising a threaded spindle connected to the motor and two members mounted for movement on and along the spindle, the twO members being alternatively engaged by the threaded spindle, and the drive means being operated by the motor, 5. a dial with an indicator for indicating weight, a. the dial indicator being connected to, and operated by, the drive means, and 6. a coupling for connecting a respective one of the sliding tapes to the drive means, a. the connected sliding tap being moved by the drive means to a balancing position in respect of the resistance associated therewith wherein the input signal to the amplifier is substantially zero.