Mettler-toledo Ag

Mettler-toledo Gmbh

Ferdinand Schneider

Hans-Rudolf Burkhard

Dominique Genoud

Peter Schilling

Thomas Köppel

Markus Uster

Hans-Rudolph Burkhard

Martin Heusser

Ernst Tschopp

George Fankhauser

Bruno Bonino

Franz Balsen

The invention concerns a calibration device () for a force-measuring device (), specifically a balance, with an electrically controllable force-generating means () designed to be coupled to a force-measuring cell () of a force-measuring device () in such a way that a predefined force (F) can be applied to the force-measuring cell (), so that the latter generates a measuring signal (S) which correlates to the applied force (F) and which can be transmitted to a processing unit (, PU), where it can be processed in reference to the predefined force (F). The calibration device () includes a calibration control unit (CCU) which has access to at least one predefined parameter (P) characterizing the force-measuring device (() and/or the calibration device (), wherein the calibration control unit (CCU) can be connected by way of a communications link () to the processing unit (, PU) in order to exchange information signals (S) with the latter, and wherein the calibration control unit (CCU) is configured to generate control signals based on the information signals (S) and the parameter (P) in order to thereby control the force-generating means ().

Calibration device for a force-measuring device, and force-measuring device

A force-transmitting mechanism of a gravimetric measuring instrument, with a stationary portion, and a load-receiving portion that is joined through a force-transmitting connection to a measurement transducer that is arranged on the stationary portion. A calibration weight may be coupled to the force-transmitting mechanism in such a way as to minimize the degree to which changes of the geometry can affect the force that the calibration weight exerts on the measurement transducer.

Force-transmitting mechanism with a calibration weight that can be coupled and uncoupled

A force-transmitting mechanism () has stationary and load-receiving portions (). The load-receiving portion is joined to a measurement transducer on the stationary portion through a force-transmitting connection, directly or through at least one coupling element () and at least one lever (). The force-transmitting mechanism has a parallel-guided coupling means (), a calibration lever () with a fulcrum on the stationary portion, and calibration lever arms (), one of which is rigidly connected to a calibration weight (). The parallel-guided coupling means () is arranged between the second calibration lever arm and the at least one coupling element or an arm () of the lever. The parallel-guided coupling means is divided into fixed and parallel-guided coupling parts (), which allows a force to be transmitted between the coupling parts. Parallel elements of the parallel-guided coupling part absorb relative traverse displacements from transmitted forces.

The disclosed embodiments describe force-transmitting devices for use in gravimetric measuring instruments. The force-transmitting devices scale the force from a calibration weight to facilitate calibration and weighing. The devices comprise unidirectional coupling elements. The unidirectional coupling element comprises coupling element parts. The elements may be adapted to transmit only a tensile force or only a compressive force to a measurement transducer. Adapting the unidirectional coupling element to transmit one type of force or the other may be done by selecting an appropriate arrangement of coupling element parts. The coupling element parts are adapted to transmit force along a midline axis by either a projection and v-shaped groove coupling or projections on the first part mated with surfaces on the second part adapted to receive and guide the first part.

Force-transmitting device with a calibration weight that can be coupled and uncoupled

A weighing cell module with a force-transfer mechanism that includes a parallel-guiding linkage with a vertically movable parallelogram leg and a spatially fixed parallelogram leg, is equipped with a mounting area for a first weighing-pan support device with a single-point connection of a weighing pan, as well as with a mounting area for a second weighing-pan support device with a multiple-point connection, particularly a four-point connection, of a weighing pan, wherein the first and the second mounting area are each connected to the force-transfer mechanism. As a result, the weighing cell module can be used to manufacture different types of balances in a design family of balances, where each different type within the family is designed for a different maximum load.

Scale pan mount for single-point or multi-point mounted scale pan

To protect a force-measuring device from being damaged by an overload, the load receiver ( ) has a first part ( ) that receives the force to be measured and a second part ( ) that transfers the force to a measuring transducer. The two parts, together with two parallel guide members ( ) by which they are connected, are portions of a monolithic material block that are separated from each other by a material-free space ( ) in the form of a thin linear cut. A pre-tensioned elastic element ( ) urging the two parts ( ) into spring-loaded engagement is arranged inside a cavity of the second part ( ).

Overload protector for a force-measuring device, particularly for a balance

To counteract the adverse effects associated with mounting a parallel-guiding device on a supporting part of a balance, the attachment area (,) is located on a portion (,) of the stationary leg (,) of the parallel-guiding device. Portion,projects into the space between the two guide links,and,by which the load-receiving movable leg (,) of the parallelogram is guided in parallel motion relative to the stationary leg (,).

Arrangement for mounting a parallel-guiding device in a force measuring apparatus

In a balance with a parallel-guided load receiver (,) and a force-reduction mechanism using a series of two levers (,), the input arm (,) of the first lever (,) to which the weight force of the load to be weighed is applied is extended into the space outside of the load receiver (,) and past a force transducer (,) arranged in that space, the end of the extension being equipped with a coupling area (,) for a calibration weight (,). This accomplishes a large lever-reduction of the calibration force in combination with a compact configuration, thus allowing a full-load calibration of the balance to be performed with a relatively small calibration weight (,).

Balance with a mechanical coupling area for a calibration weight

A shock protection device for a force measuring apparatus, particularly a balance, which includes a material block with a stationary parallelogram side member, a deflectable parallelogram side member serving for receiving the force to be measured, two guide members which are bending-elastic in the plane of the parallelogram and which connect the two parallelogram side members, and at least one lever which is connected through a coupling member to the deflectable parallelogram side member. The shock protection device includes a safety bolt inserted into a bore extending at least partially through the force measuring apparatus, wherein the safety bolt is connected without play to one of the components forming the force measuring apparatus, while the safety bolt has radial play relative to the remaining components through which the bolt extends.

Shock protection device for a force measuring apparatus

An overload protection device for a precision balance includes a measuring cell having a short travel distance, a parallel guide unit connected to a load receiving unit, and an auxiliary parallel guide unit whose guide members are connected to the load receiving unit, on the one hand, and to a weighing dish carrier member, on the other hand, wherein the guide members of the auxiliary parallel guide unit are pretensioned by at least one spring and form a rigid unit with the load receiving unit within the loading range of the balance. The auxiliary parallel guide unit includes an upper guide member and a lower guide member, wherein the two ends of the guide members of the auxiliary parallel guide unit on the side of the weighing dish are connected to each other by at least one guide bolt fastened to the upper guide member and the lower guide member. The guide bolt extends with play through a support plate which is fixedly connected to the load receiving unit of the measuring cell. The at least one spring is mounted between the upper guide member and the support plate.

Overload protection device for a precision balance

A balance with a weighing system protected against overloading includes a load receiving member and a weighing dish placed on the load receiving member. The weighing dish rests on dampening elements which are mounted at ends of two U-shaped levers which are supported in a central yoke. The yoke includes abutments which hold the two levers in a horizontal position in an articulated manner. When a load which is within the weighing range is applied to the weighing dish, the two levers and the yoke form a rigid unit. If an excess load is placed on the weighing dish, either dynamically or statically, the two levers are pivoted and tension a stack of springs mounted in the abutments. In addition to dampening by the pivoting of the two levers and tensioning of the stack of springs, additional dampening is effected by dampening elements between the lever ends and the weighing dish. The levers each have a cross member and stop pedestals mounted underneath the cross member conduct any excess load directly into the housing bottom or legs attached to the housing bottom.

Growing community of inventors

Winterthur, Switzerland

Ferdinand Schneider