Back to results
US 12,566,087 B2Granted
Scale with overload detection
AssigneeWipotec GmbH
InventorsJan Gottfriedsen, Frank Schmitt
Life of this patent
Estimating the term…
Abstract
The disclosure relates to a scale operating according to the principle of electrodynamic force compensation and to a method for its operation. An automatic switchover from a measuring mode to an overload mode is provided for detecting overload forces. In this overload mode the load resistance formed by a coil and at least one measuring resistor is reduced in order to allow a higher coil current at the same output stage power.
Claims20
A scale which operates according to the principle of electrodynamic force compensation, the scale including:
- (a) a carrying coil and a magnet which interact with one another and are movable relative to one another, wherein the carrying coil is connected in a load coil circuit to receive a carrying coil current supplied to the carrying coil from an output stage;
- (b) a resistor arrangement which forms an electrical load resistance for the load coil circuit, the resistor arrangement comprising the carrying coil having a coil electrical resistance and a measuring resistor arrangement having a measuring electrical resistance, wherein the scale operates in a measuring mode for a force acting on the scale in a predetermined load measuring range, the electrical load resistance having a measuring mode resistance value when the scale is operating in the measuring mode so that the carrying coil current supplied to the carrying coil by the output stage comprises a carrying coil measuring current to compensate, by electrodynamic interaction between the carrying coil and the magnet, for the force acting on the scale and the scale determines a measured value associated with the force acting on the scale from a measuring voltage drop at the measuring resistor arrangement;
- and
- (c) a switching arrangement for switching from the measuring mode to an overload mode for detecting an overload force acting on the scale which exceeds or falls below the predetermined load measuring range, wherein in the overload mode the electrical load resistance is reduced from the measuring mode resistance value and wherein the carrying coil current supplied to the carrying coil by the output stage comprises a carrying coil overload current to compensate, by electrodynamic interaction between the carrying coil and the magnet, for the overload force acting on the scale;
- (d) wherein the switching from the measuring mode to the overload mode occurs automatically.
2 more elements
A method for operating a scale according to the principle of electrodynamic force compensation, wherein the scale includes,
- (i) a carrying coil and a magnet which interact with one another and are movable relative to one another, wherein the carrying coil is connected in a load coil circuit to receive a carrying coil current supplied to the carrying coil from an output stage;
- and
- (ii) a resistor arrangement which forms an electrical load resistance for the load coil circuit, the resistor arrangement comprising the carrying coil having a coil electrical resistance and a measuring resistor arrangement having a measuring electrical resistance, wherein the scale operates in a measuring mode for a force acting on the scale in a predetermined load measuring range, the electrical load resistance having a measuring mode resistance value when the scale is operating in the measuring mode so that the carrying coil current supplied to the carrying coil by the output stage comprises a carrying coil measuring current to the carrying coil to compensate, by electrodynamic interaction between the carrying coil and the magnet, for the force acting on the scale and the scale determines a measured value associated with the force acting on the scale from a measuring a voltage drop at the measuring resistor arrangement,
- the method including:
- (a) detecting an overload force that exceeds or falls below the predetermined load measuring range;
- and
- (b) switching to an overload mode in which the electrical load resistance is reduced from the measuring mode resistance value to minimize relative movement between the magnet and carrying coil, wherein the switching to the overload mode occurs automatically.
4 more elements
Dependencies are inferred from the claim text.