GB2162322A - Force transducer - Google Patents

Force transducer Download PDF

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Publication number
GB2162322A
GB2162322A GB8518480A GB8518480A GB2162322A GB 2162322 A GB2162322 A GB 2162322A GB 8518480 A GB8518480 A GB 8518480A GB 8518480 A GB8518480 A GB 8518480A GB 2162322 A GB2162322 A GB 2162322A
Authority
GB
United Kingdom
Prior art keywords
force
holes
strain gauges
force transducer
bridge
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB8518480A
Other versions
GB8518480D0 (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koninklijke Philips NV
Original Assignee
Philips Gloeilampenfabrieken NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Philips Gloeilampenfabrieken NV filed Critical Philips Gloeilampenfabrieken NV
Publication of GB8518480D0 publication Critical patent/GB8518480D0/en
Publication of GB2162322A publication Critical patent/GB2162322A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
    • G01L1/2206—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
    • G01L1/2218—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports the supports being of the column type, e.g. cylindric, adapted for measuring a force along a single direction
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G3/00—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances
    • G01G3/12—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing
    • G01G3/14—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing measuring variations of electrical resistance
    • G01G3/1402—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
    • G01G3/1408—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports the supports being of the column type, e.g. cylindric

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Force In General (AREA)
  • Force Measurement Appropriate To Specific Purposes (AREA)

Abstract

A force transducer used more particularly in weighing cells comprises a cylindrical compression member (1), whose end faces (2,3) are acted upon by the force (4) to be detected. It has slotted blind holes (5,6) extending longitudinally of the direction of force and arranged opposite each other, whose bottom surfaces (7,8) constitute a bridge, on which is provided strain gauges (10-13) extending longitudinally and transversely of the direction of force. In order to be able to adjust accurately the sensitivity and hence the linear measuring range to predetermined values, the bridge (9) has through-holes (14,15) situated before and behind the strain gauges (10-13) in the direction of force. The sensitivity of the force transducer can be increased by deepening and widening the slotted blind holes (5 and 6) and can be reduced again by increasing the diameter of the through-holes (14 and 15) and can hence be accurately adjusted to a predetermined value. <IMAGE>

Description

SPECIFICATION Force transducer The invention relates to a force transducer, more particularly for weighing cells, comprising a cylindrical compression member, whose end faces are acted upon by the force to be detected and which has slotted blind holes extending longitudinally of the direction of force and arranged opposed each other, whose bottom surfaces constitute a bridge on which strain gauges are provided which extend longitudinally and transversely of the direction of force.
DE-Gbm 8030920 discloses such a force transducer, whose sensitivity can be increased by deepening or widening the slotted blind holes provided in the compression member.
However, if due to excessive removal of material during milling of the slotted blind holes the predetermined values for sensitivity and measuring range of the force transducer are exceeded, there are no possibilities in the known force transducer of reducing again the sensitivity of the force transducer and hence of enlarging its linear measuring range.
The present invention has for its object to provide a force transducer, whose sensitivity and hence whose linear measuring range can be accurately adjusted to predetermined values, In a force transducer of the kind mentioned in the opening paragraph, this object is achieved in that the bridge has through-holes situated before and/or behind the strain gauges in the direction of force.
The sensitivity of the force transducer not only can be increased by deepening or widening the slotted blind holes, but can also be reduced by increasing the bore diameter and by reducing the bore distance of the throughholes so that the sensitivity and hence the linear measuring range of the force transducer can be adjusted very accurately to predetermined values.
An embodiment of the invention will be described more fully hereinafter with reference to the drawings. In the drawings: Figure 1 shows partly in sectional view a side elevation of a compresson member of a force transducer, Figure 2 is the side elevation of the compression member in a position rotated through 90' about its longitudinal axis with respect to Fig. 1.
Fig. 1 is a side elevation of a cylindrical compression member 1, whose end faces 2 and 3 are acted upon by the force 4 to be detected. The compression member 1 has slotted blind holes 5 and 6 which extend longitudinally of the direction of force and which are shown partly in sectional view in Fig. 1. The bottom surfaces 7 and 8 of the slotted blind holes 5 and 6 constitute a bridge 9, on which are provided strain gauges 10 to 1 3 extending longitudinally and transversely of the direction of force. In order to reduce the sensitivity of the force transducer, through-holes 14 and 1 5 are provided in the bridge 9 before and behind the strain gauges 10 to 1 3 in the direction of force.
Fig. 2 shows the compression member 1 in a position rotated through 90 about its longitudinal axis so that the slotted blind hole 5, the strain gauges 10 and 11 and the throughholes 14 and 1 5 can be seen.
The depth of the oppositely arranged slotted blind holes 5 and 6 determines the thickness b of the bridge 9. The deformability of the compression member 1 and hence the sensitivity of the force transducer are now larger as the depth is larger over which the slotted holes blind 5 and 6 are milled into the compression member and thus as this dimension b is smaller. The sensitivity of the force transducer can also be increased by increasing the width a of the slotted blind holes 5 and 6.
If the slotted blind holes 5 and 6 have become excessively wide or excessively deep due to an excessive removal of material, so that the deformability of the compression member 1 has become excessively large in the area of the strain gauges 10 to 13, the deformability of the compression member 1 in the area of the strain gauges 10 and 1 3 can be reduced again by providing through-holes 14 and 1 5 so that the sensitivity of the force transducer can thus also be reduced. The deformability of the strain gauges 10 and 1 2 in this area is thus reduced to a greater extent as the diameter of the through-holes 1 4 and 1 5 is larger and as their relative distance is smaller.The sensitivity of the force transducer can also be reduced, however, by providing blind holes in the bridge 9.
Without through-holes 1 4 and 1 5 being provided, the compression member 1 is deformed when acted upon by a force 4 in a manner such that the strain gauges 10 and 1 2 extending longitudinally of the direction of force are shortened and the strain gauges 11 and 1 3 extending transversely of the direction of forces are lengthened.
If through-holes 1 4 and 1 5 are provided in the compression member 1, when a force 4 acts upon it, the lines of force are concentrated to the parts of the bridge 9 remaining on either side of the through-holes 1 4 and 1 5. Thus, the distribution of the lines of force at the centre of the compression member 1 becomes more inhomogeneous, i.e. the lines of force are concentrated also at the centre of the compression member 1 more strongly to the region lying on either side of the strain gauges 10 to 1 3 as the diameter of the through-holes 1 4 and 1 5 is larger and as their distance from the strain gauges 10 to 1 3 is smaller.However, the smaller the number of lines of force extending through the region of the bridge 9 lying between the strain gauges 10 to 13, the smaller is the extent to which this region is deformed when acted upon by a force 4 and the smaller is the extent to which the strain gauges 10 to 1 3 are thus deformed. As a result, the sensitivity of the force transducer is reduced and the measuring range having a linear characteristic is enlarged. The characteristic becomes non-linear if the thickness b of the bridge 9 in the region of the strain gauges 10 to 1 3 increases due to an excessively high density of lines of force so that the strain gauges 10 and 1 2 extending longitudinally of the direction of the force 4 are lengthened upon introduction of force.
A force transducer tested in experiments comprises a cylindrical compression member 1 having a diameter of 54 mm, which has slotted blind holes 5 and 6 having a length of 60 mm and a width of 21 mm. These holes are milled so deep into the compression member 1 that a bridge 9 is obtained having a thickness of 3 mm.
Without through-holes 14 and 1 5 being provided, the compression member 1 can be loaded up to about 14 t without the characteristic of the force transducer becoming nonlinear. If on the contrary the compression member 1 has through-holes 14 and 15 having a diameter of 6 mm and lying at a relative distance of 48 mm, the cdmpression member 1 can be loaded up to about 1 5.5 t. The load capacity of the compression member is about 1 6.5 t with a through-hole diameter of 8 mm and is 1 8 t with through-hole diameter of 10 mm.

Claims (2)

1. A force transducer comprising a cylindrical compression member whose end faces are acted upon by the force to be detected and which has slotted blind holes extending longitudinally of the direction of force arranged opposite each other, whose bottom surfaces constitute a bridge on which are provided strain gauges extending longitudinally and transversely of the direction of force, characterized in that the bridge has throughholes situated before and/or behind the strain gauges in the direction of force.
2. A force transducer substantially as herein described with reference to the accompanying drawings.
GB8518480A 1984-07-26 1985-07-22 Force transducer Withdrawn GB2162322A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19843427573 DE3427573A1 (en) 1984-07-26 1984-07-26 Force transducer

Publications (2)

Publication Number Publication Date
GB8518480D0 GB8518480D0 (en) 1985-08-29
GB2162322A true GB2162322A (en) 1986-01-29

Family

ID=6241634

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8518480A Withdrawn GB2162322A (en) 1984-07-26 1985-07-22 Force transducer

Country Status (4)

Country Link
JP (1) JPS6141934A (en)
DE (1) DE3427573A1 (en)
FR (1) FR2568368A1 (en)
GB (1) GB2162322A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4789035A (en) * 1988-03-28 1988-12-06 Eaton Corporation Load cell
US5076375A (en) * 1987-11-30 1991-12-31 Mettler-Toledo, Inc. Load cell
DE19537288A1 (en) * 1995-07-07 1997-01-09 Hottinger Messtechnik Baldwin Rod shaped weighing cell or force detector using strain gauges - has metallic cover extending only over small part of cell circumference and sealingly connected at edges to weighing cell
EP0800069A1 (en) * 1996-04-01 1997-10-08 Societa' Cooperativa Bilanciai - Campogalliano a Responsabilita' Limitata Column force transducer
GB2362471A (en) * 2000-01-19 2001-11-21 James Eric Turner Rail stress measurement
WO2015010683A1 (en) 2013-07-26 2015-01-29 Hottinger Baldwin Messtechnik Gmbh Rod-shaped force transducer with simplified adjustment
WO2015010684A1 (en) 2013-07-26 2015-01-29 Hottinger Baldwin Messtechnik Gmbh Rod-shaped force transducer with improved deformation behavior

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4416442A1 (en) * 1994-05-11 1995-11-16 Hottinger Messtechnik Baldwin Method and device for calibrating a measuring body of a transducer
US5910645A (en) * 1994-05-11 1999-06-08 Hottinger Baldwin Messtechnik Gmbh Method and apparatus for making load cells less sensitive to off-center load applications
DE19613038A1 (en) * 1996-04-01 1997-10-02 Hottinger Messtechnik Baldwin Rod-shaped load cell
DE102020126521A1 (en) 2020-10-09 2022-04-14 Minebea Intec GmbH Load cell with improved linearity

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5076375A (en) * 1987-11-30 1991-12-31 Mettler-Toledo, Inc. Load cell
US4789035A (en) * 1988-03-28 1988-12-06 Eaton Corporation Load cell
DE19537288A1 (en) * 1995-07-07 1997-01-09 Hottinger Messtechnik Baldwin Rod shaped weighing cell or force detector using strain gauges - has metallic cover extending only over small part of cell circumference and sealingly connected at edges to weighing cell
US5712432A (en) * 1995-07-07 1998-01-27 Hottinger Baldwin Messtechnik Gmbh Pin load cell for weighing
EP0800069A1 (en) * 1996-04-01 1997-10-08 Societa' Cooperativa Bilanciai - Campogalliano a Responsabilita' Limitata Column force transducer
GB2362471B (en) * 2000-01-19 2004-08-04 James Eric Turner Rail stress measurement
GB2362471A (en) * 2000-01-19 2001-11-21 James Eric Turner Rail stress measurement
WO2015010683A1 (en) 2013-07-26 2015-01-29 Hottinger Baldwin Messtechnik Gmbh Rod-shaped force transducer with simplified adjustment
DE102013012507A1 (en) 2013-07-26 2015-01-29 Hottinger Baldwin Messtechnik Gmbh Rod-shaped load cell with simplified adjustment
WO2015010684A1 (en) 2013-07-26 2015-01-29 Hottinger Baldwin Messtechnik Gmbh Rod-shaped force transducer with improved deformation behavior
DE102013012506A1 (en) 2013-07-26 2015-01-29 Hottinger Baldwin Messtechnik Gmbh Rod-shaped force transducer with improved deformation behavior
DE102013012507B4 (en) * 2013-07-26 2016-06-16 Hottinger Baldwin Messtechnik Gmbh Rod-shaped load cell with simplified adjustment
US9791332B2 (en) 2013-07-26 2017-10-17 Hottinger Baldwin Messtechnik Gmbh Rod-shaped force transducer with improved deformation behavior
US10067009B2 (en) 2013-07-26 2018-09-04 Hottinger Baldwin Messtechnik Gmbh Rod-shaped force transducer with simplified adjustment

Also Published As

Publication number Publication date
FR2568368A1 (en) 1986-01-31
JPS6141934A (en) 1986-02-28
DE3427573A1 (en) 1986-02-06
GB8518480D0 (en) 1985-08-29

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)