Mettler-toledo Ag

Mettler-toledo Gmbh

Volker Ziebart

Jean-Maurice Tellenbach

Urs Loher

Hans-Rudolf Burkhard

Klaus Peter Selig

Kurt Jensen

A load cell () has a deformable body with upper and lower contact surfaces (), through which a force is introduced. Support points () of the contact surfaces define a line of action () of the force. At least one column-shaped portion () of the deformable body has a central longitudinal axis () and a circumferential surface whose generating line runs parallel to the central longitudinal axis (). A first determining means () installed on the column-shaped portion converts a mechanical deformation into an electronic signal, and a second determining means () installed on the column-shaped portion converts a deviation of the central longitudinal axis () from the line of action () into a representative signal. Each determining means has at least one strain gauge.

Load cell with a means to compensate for errors due to misalignment

An interior space of the at least one housing of a force-measuring device is filled with a gas composition that is distinguishable in at least one parameter from the ambient atmosphere. A sensor that is arranged in the interior space, or on the housing, measures this distinguishable parameter. A processing unit of the force-measuring device compares signals obtained from the sensor to monitor and determine the condition of the force-measuring device.

Method of monitoring and/or determining the condition of a force-measuring device, and force-measuring device

A coil for an inductive sensor, such as a coil which is used in a sensor that operates according to the principle of electromagnetic force compensation for converting an amount of force generated by a load applied to a force-measuring cell into an electrical signal, is provided with protection against the penetration of moisture. The protection includes a protective covering with a surface-smoothing undercoating applied to the coil, on which a second level of coverage is applied as a protective coating against the penetration of moisture.

Moisture protection for an electromagnetic coil

In a force-measuring cell with a deformable body and with at least one strain gauge which has a strain-sensitive electrical resistor track arranged on a polymer carrier substrate, the strain gauge is bonded to the deformable body by an adhesive layer of an inorganic-organic hybrid polymer. For the bonding of the strain gauge to the deformable body, an adhesive compound having an inorganic-organic hybrid polymer in solution is applied to the deformable body, whereupon the strain gauge is placed on the hybrid polymer layer, and the adhesive layer is subsequently hardened at a temperature between 80&#xb0; C. and 130&#xb0; C. For the hardening of the adhesive layer, the deformable body with the strain gauge is exposed to the increased temperature for a time period between a half hour and three hours.

Bonding of strain gauges to the deformable body of a force-measuring cell

A strain gauge with a strain-sensitive electrical resistor track and connector electrodes for contacting the resistor track arranged on a carrier substrate is provided with a protective coating having inorganic materials and covering at least part of the carrier substrate and/or of the resistor track and/or of the connector electrodes. The build-up structure of the protective coating over the range of the coating thickness is inhomogeneous, and the protective coating is underlaid with a surface-smoothing polymer layer which evens out rough surface portions of the area to be coated. The layer thickness of the surface-smoothing layer is at least equal to the thickness of the protective coating. A strain gauge of this type can be used in a force-measuring cell, where the surface-smoothing layer and the protective coating can be deposited after an uncoated strain gauge has been installed on the deformable body of the force-measuring cell.

Moisture protection for an electromechanical transducer

A multilayered coating is disclosed as a protective coating against moisture penetration for strain gauges that are or can be installed on a deformable body of a force-measuring cell. A strain gauge has a strain-sensitive electrical resistor track and connector electrodes for contacting the resistor track arranged on a carrier substrate, with a multilayered coating covering at least a part of the carrier substrate and/or of the resistor track and/or of the connector electrodes as a protective coating against moisture penetration. The multilayered coating is composed of an alternating sequence of a polymer layer and a barrier layer and consists of at least three thin individual layers. In the case where a multilayered coating is applied to a strain gauge that is already installed on the deformable body of a force-measuring cell, the multilayered coating can in addition also cover a part of the deformable body.

Growing community of inventors

Schlatt, Switzerland

Volker Ziebart