Load cell for a scale

Patent metadata

Field	Value
Publication number	US-10837820-B2
Application number	US-201815908232-A
Country	US
Kind code	B2
Filing date	Feb 28, 2018
Priority date	Mar 2, 2017
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

The invention relates to a load cell for a scale having a monolithically configured measurement body that has a force reception section, a force introduction section, and a joint section arranged between the force reception section and the force introduction section, wherein the measurement body has a longitudinal axis and an axial end at the force reception side and an axial end at the force introduction side; having at least one strain gauge arranged at the upper side on the joint section for detecting a stretching deformation of the measurement body; and having a circuit board that is electrically connected to the at least one strain gauge, that is arranged at the force reception side, and that has electronics arranged thereon for processing at least one output signal of the at least one strain gauge.

First claim

The invention claimed is:

1. A load cell for a scale, the load cell comprising:
a monolithically configured measurement body defining a force reception section, a force introduction section, and a joint section arranged between the force reception section and the force introduction section, wherein the measurement body defines a longitudinal axis extending between a first axial end at the force reception section and a second axial end at the force introduction section, wherein the measurement body further defines an upper side extending between the first axial end and the second axial end, and wherein the force reception section defines a recess open on the upper side and the first axial side;
at least one strain gauge arranged at the upper side of the measurement body on the joint section and configured for detecting a stretching deformation of the measurement body; and
a circuit board positioned within the recess and electrically connected to the at least one strain gauge,
wherein the circuit board comprises electronics configured for processing at least one output signal of the at least one strain gauge and a hardware interface electrically connected to the electronics,
wherein the circuit board is configured to be inserted into the recess in a direction parallel to the longitudinal axis, and
wherein the hardware interface comprises a plug-in connection at the first axial end of the measurement body with a plug-in direction parallel to the longitudinal axis.

2. The load cell in accordance with claim 1 ,
wherein the electronics includes an analog-to-digital converter.

3. The load cell in accordance with claim 1 ,
wherein the circuit board is completely sunk into the recess.

4. The load cell in accordance with claim 1 ,
wherein the circuit board projects outwardly over the first axial end of the measurement body at the force reception section.

5. The load cell in accordance with claim 1 ,
wherein the hardware interface projects outwardly over the first axial end of the measurement body at the force reception section.

6. The load cell in accordance with claim 1 ,
wherein the circuit board is populated at one side,
wherein the circuit board is inserted into the recess with the populated side facing downwardly and/or with a solder side, opposite the populated side, facing upwardly.

7. The load cell in accordance with claim 1 ,
wherein the circuit board is fastened in a respective hole formed in the recess and having an internal thread, by means of at least one fastening screw extending through a respective passage hole provided in the circuit board.

8. The load cell in accordance with claim 1 ,
wherein the circuit board has at least one spacer at a downwardly directed side.

9. The load cell in accordance with claim 8 ,
wherein the respective spacer is configured as a spacer sleeve and with a respective fastening screw extending through the respective spacer sleeve.

10. The load cell in accordance with claim 1 ,
wherein a protective cover is provided for the circuit board, with the circuit board being combined with the protective cover to form a module that is inserted into the recess.

11. The load cell in accordance with claim 10 ,
wherein the circuit board and the protective cover are mechanically connected to one another via a clip connection.

12. The load cell in accordance with claim 11 ,
wherein the protective cover has a plurality of bending snap-in hooks that project in the direction of the circuit board and that engage behind the circuit board with shape matching in the assembled state to form the clip connection.

13. The load cell in accordance with claim 10 ,
wherein the protective cover has a web which projects in the direction of the circuit board, which is formed at least at the oppositely disposed sides with respect to the longitudinal axis of the measurement body, and on which the circuit board lies.

14. The load cell in accordance with claim 13 ,
wherein the protective cover is at least sectionally web-free at its front side facing the end of the measurement body at the force reception side, with at least one hardware interface being arranged at the web-free front side or at the web-free region of the front side.

15. The load cell in accordance with claim 1 ,
wherein a removal calibration cover is provided that is fastened to the force reception section of the measurement body by means of a fastening element secured by a calibration mark and that covers the recess from above.

16. The load cell in accordance with claim 15 ,
wherein the fastening element is a fastening screw that is screwed into a hole that is formed in the recess, and that has an internal thread, with the fastening screw extending through a passage hole provided in the calibration cover and through a corresponding passage hole provided in the circuit board.

17. The load cell in accordance with claim 15 ,
wherein the force reception section has at least one fastening hole for a respective fastening means for fastening the load cell to a scale, with the calibration cover simultaneously also covering at least one of the respective fastening hole and the respective fastening means.

18. The load cell in accordance with claim 1 ,
wherein the measurement body has a groove extending transversely to the longitudinal direction of the measurement body at the upper side between the force introduction section and the joint section.

19. A scale having a load cell, the load cell comprising:
a monolithically configured measurement body defining a force reception section, a force introduction section, and a joint section arranged between the force reception section and the force introduction section, wherein the measurement body defines a longitudinal axis extending between a first axial end at the force reception section and a second axial end at the force introduction section, wherein the measurement body further defines an upper side extending between the first axial end and the second axial end, and wherein the force reception section defines a recess open on the upper side and the first axial side;
at least one strain gauge arranged at the upper side of the measurement body on the joint section and configured for detecting a stretching deformation of the measurement body; and
a circuit board positioned within the recess and electrically connected to the at least one strain gauge
wherein the circuit board comprises electronics arranged configured for processing at least one output signal of the at least one strain gauge and a hardware interface electrically connected to the electronics,
wherein the circuit board is configured to be inserted into the recess in a direction parallel to the longitudinal axis, and
wherein the hardware interface comprises a plug-in connection at the first axial end of the measurement body with a plug-in direction parallel to the longitudinal axis.

Assignees

• Bizerba Se & Co Kg

Inventors

• Schreiber Annika
• Metzger Frank

Classifications

• G01G3/1402 Primary

  Special supports with preselected places to mount the resistance strain gauges; Mounting of supports · CPC title

• G01G21/244

  combined with flexure-plate fulcrums (flexure-plate fulcrums G01G21/07) · CPC title

• G01L1/2231

  the supports being disc- or ring-shaped, adapted for measuring a force along a single direction · CPC title

• G01G3/1404 Primary

  combined with means to connect the strain gauges on electrical bridges · CPC title

• G01L1/225

  Measuring circuits therefor · CPC title