Kistler Instrumente Ag

K.k. Holding Ag

Mario Giorgetta

Hans Conrad Sonderegger

Peter Wolfer

Reto Calderara

Paul Engeler

Markus Caprez

Dario Barberis

A multicomponent force and moment measuring arrangement wherein shear forces are converted into moments and transmitted via tensile-compressive forces onto piezoelectric rod elements, while axial compressive-tensile forces are transmitted directly onto the same piezoelectric rod elements. With appropriate arrangement of the piezoelectric rods and their signal evaluation, transducers and dynamometers of entirely new type can be constructed, in which the necessary electronics package can be located between the piezoelectric rod elements for certain applications.

Multicomponent force and moment measuring arrangement

An interposed sensor having a housing whose lateral extend is not greater than the lateral extend of the machine parts is to be installed between and having a plurality of measuring elements welded under preloading to the housing. Electronics including charge amplifiers are integral with the housing, either interior the lateral extend or in an annular compartment.

Interposed force sensor including amplifiers

The invention comprises a force measuring system for the dynamic determination especially of axle loads, speed, vehicle wheelbase and gross weight. The force measuring system is laid permanently in the roadway. It is of modular assembly, consisting of the amplifier (11), sensor (12) and terminal module (13). The individual modules may be coupled tightly by plug-and-socket connections, welding flanges or glued flanges. The sensor module (12) consists of a hollow section (1), in which piezo-elements (4) are fitted under elastic preload. The piezo-elements (4) are accommodated in the hollow section (1) at intervals of typically 5 to 10 cm, and they may be connected all together with only one electrically conductive foil (5) to the signal processing facility (19), or groupwise or even singly. According to this subdivision the road width can be sectioned as desired, in order to obtain a road loading diagram for instance. The hollow section is designed so that it can be opened elastically by lateral clamping, to allow mechanically interconnected piezo-elements (4) to be inserted. After releasing this clamping, the piezo-elements (4) are under high elastic preload. In this way any tolerance errors can be overcome, so that costly machining operations are unnecessary and all parts with standard tolerances can be used.

Force sensor systems especially for determining dynamically the axle

The invention relates to a charge amplifier circuit with a control loop for resetting, which for minimizing the leakage currents that falsify the measuring results includes two diodes (D.sub.1) and (D.sub.2), connected antiparallel in the loop and constituting input protection diodes of an integrated circuit (ISK). In the operating (measuring) phase the diode resistance (R.sub.D) is extremely high and the voltage drop over the diode pair is small, so that no significant leakage current gets through onto the charge amplifier input IN.sub.Q. In the reset phase the diode resistance (R.sub.Dr) is practically nil.

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Winterthur, Switzerland

Mario Giorgetta