WO2007143838A1 - Cellule de charge à profil bas - Google Patents

Cellule de charge à profil bas Download PDF

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Publication number
WO2007143838A1
WO2007143838A1 PCT/CA2007/001050 CA2007001050W WO2007143838A1 WO 2007143838 A1 WO2007143838 A1 WO 2007143838A1 CA 2007001050 W CA2007001050 W CA 2007001050W WO 2007143838 A1 WO2007143838 A1 WO 2007143838A1
Authority
WO
WIPO (PCT)
Prior art keywords
base
load cell
strain gauge
weight
contact knob
Prior art date
Application number
PCT/CA2007/001050
Other languages
English (en)
Other versions
WO2007143838A9 (fr
Inventor
Gerald S. Simons
Original Assignee
Simons Gerald S
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 Simons Gerald S filed Critical Simons Gerald S
Publication of WO2007143838A1 publication Critical patent/WO2007143838A1/fr
Publication of WO2007143838A9 publication Critical patent/WO2007143838A9/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G19/00—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups
    • G01G19/08—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for incorporation in vehicles
    • G01G19/083—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for incorporation in vehicles lift truck scale
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G19/00—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups
    • G01G19/08—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for incorporation in vehicles
    • G01G19/12—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for incorporation in vehicles having electrical weight-sensitive devices
    • 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
    • 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

Definitions

  • the present invention relates to devices for measuring the weight of objects.
  • the weight of an object there are many situations in which it is desired to know the weight of an object. For example, when lifting a pallet, a forklift truck driver would like to know the weight of the pallet and/or the objects on the pallet in order to load the proper amount of the objects into a delivery truck. Or, it may be beneficial to know the weight being supported by a floor so that an alarm may be sounded when the weight supported by the floor exceeds a safe level. Further, the weight of vehicles is often needed in order to determine taxes due for driving on roadways or the cost of the goods being carried by the vehicle.
  • weight sensors are placed in locations which allow for indirect measurement of the weight of objects being supported from a platform, such as a pallet or a floor. Indirect measurement is not very accurate, and usually requires complex devices to determine the weight. In other situations, weight sensors are placed directly beneath an object, but these mechanisms for supporting and measuring the weight of an object, such as a truck, are large and costly.
  • the invention may be embodied as a load cell.
  • the load cell may have a base, a contact knob and a strain gauge measuring device.
  • the strain gauge measuring device is fixed to the base, and includes at least one strain gauge.
  • a transmission device capable of transmitting a signal from the strain gauge measuring device to an analyzing circuit may be used to provide electric power to the strain gauge and to receive indications of resistance from the strain gauge.
  • the analyzing circuit may be a voltmeter.
  • the voltmeter may be electrically coupled to a computer which is programmed to correlate changes indicated by the voltmeter to a weight, and also programmed to cause a monitor to indicate a weight to a person having a desire to know the weight.
  • the contact knob may have a rounded surface. Furthermore, the contact knob may be an integral part of the base. However, the contact knob may be a distinct part, which is fixed to the base. The contact knob may be located on a side of the base that is different from the side of the base to which the strain gauge is attached.
  • the invention may be embodied as a method of weighing an object.
  • a load cell is provided.
  • the load cell may have a base, a contact knob and a strain gauge measuring device fixed to the base.
  • a first resistance of the strain gauge measuring device may be measured.
  • an object to be weighed may be supported with the contact knob.
  • a second resistance of the strain gauge measuring device is measured.
  • the first resistance and the second resistance are compared to obtain a resistance difference, and the resistance difference is correlated to a weight.
  • the weight is then displayed to a person.
  • Figure Ia which is a plan view of a load cell according to the invention
  • Figure Ib which is a cross-sectional side view of the load cell depicted in Figure Ia;
  • Figure Ic which is a cross-sectional side view of a load cell that has a contact knob that is not an integral part of the base
  • Figure 2 which is a plan view of a fork lift truck using the invention
  • Figure 3 which is a cross-sectional side view of a forklift tine, taken from the section 3—3 in Figure 2
  • Figure 4 which depicts a method according to the invention.
  • the invention may be embodied as a load cell 10 for weighing one or more objects.
  • Figures Ia and Ib show a load cell 10 according to the invention.
  • This load cell 10 has a base 13, and extending from the base 13 is a contact knob 16.
  • One or more strain gauges 19 may be fixed to the base 13 and electrically connected to form a Wheatstone bridge.
  • Fig. Ia shows the strain gauges 19 on a side of the base that is different from the contact knob 16.
  • the strain gauges 19 may be the metal film type.
  • the base 13 in Figures Ia and Ib is disk shaped.
  • Figure Ia shows the base 13 may have a circular shape, but the invention is not limited to a circular shape.
  • Figures Ia and Ib show the base 13 made from a single piece of material, but more than one piece of material may be used to form the base 13.
  • the base 13 and contact knob 16 may be made of metal.
  • Figure Ic shows an embodiment in which the base 13 is comprised of two pieces 13A and 13B.
  • the base pieces 13A and 13B may be attached to each other by welding, adhesive, or other means.
  • Figure Ia shows that the base 13 may be shaped to provide a recessed area 28.
  • the recessed area 28 is defined in part by an annualar lip 31 which extends from a central portion 34 of the base 13.
  • the annular lip 31 is provided by the base piece 13B.
  • the annular lip 31 may be provided with through holes 37 that may be used for mounting the base 13 to a desired location.
  • the strain gauges 19 are shown attached to the base 13 within the recessed area 28, and are thereby protected to some extent.
  • the contact knob 16 is on a different side of the base 13 than the strain gauges 19.
  • the contact knob 16 of the load cell 10 may include a rounded surface 22 in order to prevent twisting of the load cell 10.
  • the rounded surface 22 may be particularly useful when the base 13 of the load cell 10 is not parallel to the surface which contacts the contact knob 16.
  • the rounded surface 22 of the contact knob 16 accommodates non-linear loading of the load cell 10, and thereby reduces signal errors normally experienced when a load cell 10 is loaded in a non-linear fashion.
  • Figure Ib shows an embodiment of the load cell 10 in which the base 13 and contact knob 16 are formed from the same material to provide an integral unit.
  • Figure Ic shows an embodiment in which the base 13 and the contact knob 16 are formed separately, and then attached to each other by welding the contact knob 16 to the base 13.
  • the invention is not limited to welding the contact knob 16 to the base 13, and it will be recognized that other means of attaching may be used, such as through the use of an adhesive.
  • the weight of an object When the weight of an object is placed on the load cell 10, the weight is supported by the contact knob 16, and the base 13 is caused to flex. Flexing of the base 13 changes the resistance afforded by the strain gauges 19, and these changes may be sensed by suitable detection equipment, such as a voltmeter 25. When a voltmeter 25 is used as the detection equipment, the voltage change may be correlated to a weight and that correlated weight may be displayed to a person having an interest in knowing the weight of the object.
  • Figure Ia depicts an embodiment in which a plurality of strain gauges 19 are mounted to the base 13 at locations that are radially further from a central location of the base 13 than the edges of the contact knob 16.
  • the strain gauges 19 need not be located in this fashion in order to practice the invention.
  • FIGs 3 and 4 show how the load cell 10 of Figures Ia and Ib might be used on a forklift truck 40.
  • the contact knob 16 may be placed in contact with the tine 43, or with a cover 46, on which may be placed objects to be weighed. When objects are placed on the cover 46, the weight of the objects is supported by the contact knob 16.
  • the central portion 34 of the base 13 is caused to flex and transfers the load to the annular lip 31. The flexing of the central portion 34 is sensed by the strain gauges 19.
  • the load cells 10 described above may be made to have a height of less than about 0.5 inches, and yet provide accurate weight readings in excess of 1,000 pounds. The small height of the load cell 10 makes it ideal for use in situations where there is a small amount of space.
  • the tines 46 of a forklift truck 40 must be able to fit between an upper and a lower surface of a pallet, and in such a situation, there is a small amount of space.
  • forklift trucks have traditionally not placed load cells beneath the objects being lifted.
  • traditional forklift truck design has placed load cells on other parts of the forklift truck 40, and these locations provide an indirect measurement of the weight of objects being lifted by the forklift truck 40, and therefore tend to be less accurate.
  • the present invention permits the load cell 10 to be placed directly beneath the objects being weighed.
  • a single strain gauge 19 may be fixed to the base 13 and placed on an end of a support pillar for a building.
  • Three similar load cells 10 may be each fixed to their own pillar, and the four load cells 10 may be electrically connected so that the strain gauges 19 form a Wheatstone bridge.
  • the resulting distribution of four load cells 10 on four pillars may be used to measure the weight applied to a surface supported by the pillars.
  • a single analyzing circuit 52 may be used to measure the weight applied across a large area.
  • a transmission device 49 may be included. Such a transmission device 49 may be capable of transmitting a signal from the strain gauges 19 to an analyzing circuit 52, such as a voltmeter.
  • the transmission device 49 may be an electric conductor extending between the strain gauge 19 and the analyzing circuit 52, and the wire may be capable of transmitting electricity between the analyzing circuit 52 and one or more load cells 10. Such a conductor may be routed from the load cells 10 through a hole in the base 13.
  • the invention may be embodied as a method.
  • Figure 4 depicts one such method.
  • a load cell is provided 100.
  • the load cell has a base, a contact knob and a strain gauge measuring device fixed to the base.
  • the strain gauge measuring device may be a Wheatstone bridge, and it may be fixed to a side of the base that is different from the side from which the contact knob extends.
  • a first resistance of the strain gauge measuring device is measured 103, and then an object to be weighed is supported 106 by the contact knob.
  • a second resistance of the strain gauge measuring device is measured 109, and compared 112 to the first resistance to obtain a resistance difference.
  • the resistance difference is correlated 115 to a weight.
  • the weight is then displayed 118 to a person for example via a monitor 55.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Forklifts And Lifting Vehicles (AREA)
  • Measurement Of Force In General (AREA)

Abstract

LA présente invention concerne une cellule de charge qui possède une base, un bouton de contact et un dispositif de mesure à jauge de déformation. Lorsque le bouton de contact supporte un objet, la base fléchit, ce qui est détecté par le dispositif de mesure, et utilisé pour fournir un poids de l'objet à une personne qui souhaite connaître le poids.
PCT/CA2007/001050 2006-06-12 2007-06-12 Cellule de charge à profil bas WO2007143838A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US81258506P 2006-06-12 2006-06-12
US60/812,585 2006-06-12

Publications (2)

Publication Number Publication Date
WO2007143838A1 true WO2007143838A1 (fr) 2007-12-21
WO2007143838A9 WO2007143838A9 (fr) 2008-02-07

Family

ID=38831364

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CA2007/001050 WO2007143838A1 (fr) 2006-06-12 2007-06-12 Cellule de charge à profil bas

Country Status (1)

Country Link
WO (1) WO2007143838A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009143613A1 (fr) * 2008-05-29 2009-12-03 Weigh Point Incorporated Système de cellule de charge
CN102718144A (zh) * 2012-06-21 2012-10-10 上海港帝电气有限公司 一种集装箱龙门起重机的吊具称重传感器
US9506106B2 (en) 2013-10-15 2016-11-29 Genetrainer Limited Weight sensor suitable for use under a bed with a deformable plate mounted to a base at three contact points
EP3409635A1 (fr) * 2017-05-29 2018-12-05 Intermercato AB Système de pesage pour un dispositif de levage
US10365149B2 (en) 2013-10-15 2019-07-30 Bedsense Limited Bed based weight sensors for physiological analysis

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5873832A (ja) * 1981-10-28 1983-05-04 Toyo Baldwin:Kk 密実型ロ−ドセル
EP0640813A1 (fr) * 1993-08-25 1995-03-01 Siemens Aktiengesellschaft Capteur de force à barre annulaire avec des rainures annulaires pour le réglage nominal de la charge
WO1997022016A1 (fr) * 1994-06-21 1997-06-19 Aman James A Systeme automatise de suivi d'unites en bois ouvre

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5873832A (ja) * 1981-10-28 1983-05-04 Toyo Baldwin:Kk 密実型ロ−ドセル
EP0640813A1 (fr) * 1993-08-25 1995-03-01 Siemens Aktiengesellschaft Capteur de force à barre annulaire avec des rainures annulaires pour le réglage nominal de la charge
WO1997022016A1 (fr) * 1994-06-21 1997-06-19 Aman James A Systeme automatise de suivi d'unites en bois ouvre

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
BURTON COMPANY, 2004, Retrieved from the Internet <URL:http://www.venotek.no/index.php?option=content&task=view&id=369&Itemid=1> *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009143613A1 (fr) * 2008-05-29 2009-12-03 Weigh Point Incorporated Système de cellule de charge
CN102718144A (zh) * 2012-06-21 2012-10-10 上海港帝电气有限公司 一种集装箱龙门起重机的吊具称重传感器
US9506106B2 (en) 2013-10-15 2016-11-29 Genetrainer Limited Weight sensor suitable for use under a bed with a deformable plate mounted to a base at three contact points
US10365149B2 (en) 2013-10-15 2019-07-30 Bedsense Limited Bed based weight sensors for physiological analysis
EP3409635A1 (fr) * 2017-05-29 2018-12-05 Intermercato AB Système de pesage pour un dispositif de levage

Also Published As

Publication number Publication date
WO2007143838A9 (fr) 2008-02-07

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