GB2459106A

GB2459106A - Weigh scale calibration using GPS location data to determine local gravitational constant

Info

Publication number: GB2459106A
Application number: GB0806444A
Authority: GB
Inventors: Kevin Roy Cartwright; Robert Campbell Mcdougall
Original assignee: Illinois Tool Works Inc
Current assignee: Illinois Tool Works Inc
Priority date: 2008-04-09
Filing date: 2008-04-09
Publication date: 2009-10-14
Also published as: GB0806444D0

Abstract

A weighing scale 4 is calibrated by automatically obtaining location data with a communications device, determining a value of gravitational constant from the location data and then calibrating the scale 4 using at least the value of gravitational constant. The location data may be obtained using a GPS system or using mobile phone technology. The weigh scale may comprise a motion sensor 18 to detect movement of the sensor to a new location. The weigh scale may also comprise means to detect cut-off of the external power supply (i.e. an unplugged state). The motion sensor and power cut-off detector may be used to control when the GPS is used to obtain new location and calibration data. The location detection system (e.g. GPS) may be built-in to the weigh scale or may be provided in a portable device (e.g. PDA or mobile phone) which can interface with the weigh scale. Use of a portable device allows the user to obtain GPS data when the weigh scale is located in an area without reception without needing to move the weigh scale itself.

Description

Weighing scale

Field of invention

The present invention is concerned with weighing scales. In particular, the present invention concerns weighing scales for shops and industrial premises that need to be accurately calibrated.

Related art Weighing scales that require accurate readings are often required to be calibrated in accordance to government measures and laws. This is particularly the case where the scale is going to be used to serve goods to the public. Typically the weighing scale is made in a factory and then shipped to an operational site. When at the operational site, a person appointed or qualified under trading standards or other governmental regulations is required to come to the operational site of the weighing scale, calibrate the scale and give an official seal to the scale unit once calibrated. Official seals can usually only be applied or broken by such appointed or qualified people.

One of the reasons for calibrating on-site, rather than at the point of manufacture is that the gravitational constant g' that is required in scale measurements varies with location, even within a country. When a scale is moved from one location to another it may enter a different gravity zone' and as such may need to be manually recalibrated at the new site.

Related art in this field includes US Patent document 20020052703 which describes systems and methods for calibrating a scale portion of a scanner in a Point-of-Sale system. One such method describes scale calibration using an auto-locate system such as.

* a GPS disposed on the scanner scale. The GPS accesses satellite signals, calculates a location and provides location information to the scanner. The scale then extracts, from an optional variety of sources, the proper scale calibration data for that location.

Another related document is JP20032548 18 which describes a scale that obtains a value of gravitational acceleration using a GPS satellite, so that masses can be measured correctly.

Summary

The present invention provides a weighing scale calibration device comprising means to automatically obtain location data and determine a value of gravitational constant from the obtained data. The weighing scale calibration device obtains the location data using a communications device which is typically a GPS system and then uses this data to determine the value of gravitational constant and automatically calibrate a weighing scale. The weighing scale calibration device may be incorporated as part of a weighing scale or a portable calibration unit. A weighing scale comprising the calibration device may further comprise a motion sensor, an internal power source and control means in order to activate the communication means when the scale is being moved and is unplugged from a primary power source.

Further features of the invention are as set out in the claims and are exemplified in the following illustrative description with reference to the drawings.

Brief description of the drawings

Figure 1 shows a weighing scale incorporating the weighing scale calibration device of the present invention.

Figure 2 shows a weighing scale calibration system comprising a weighing scale and a portable calibration unit incorporating the weighing scale calibration device of the present invention. n

Figures 3a and 3b show a weighing scale calibration system of the present invention when a portable calibration unit physically interfaces with and automatically calibrates the scale.

Figure 4 shows a weighing scale incorporating the weighing scale calibration device of the present invention and means to automatically operate a GPS system when the scale is moved.

Detailed description

The present invention provides a weighing scale calibration device 2 that automatically obtains location data. By automatically obtaining location data, the need for an appointed or qualified official from a competent body to come and recalibrate a weighing instrument or scale 4 for a different value of gravitational constant can be minimised or negated completely, as there is no need to break or reapply a seal confirming the updated gravitational constant value g'.

Instead, whenever a weighing scale 4 is transferred to a new location or needs updating at its present location, the geographical location is updated with a communications device and a new value of gravitational constant g' determined from the obtained data and the scale 4 is automatically calibrated. Such recalibration is required at each site not only to compensate for any changes in gravity zone but also due to the possibilities of tampering during transit, lack of trust in foreign or other external calibrations, or other government regulations.

The calibration device 2 may be incorporated into or attached to a weighing scale, or may form part of a portable calibration unit. By having the communications device and its associated communications securely contained within the scale 4 and/or portable calibration unit, a non authorised person such as an ordinary installation technician can set up the scale 4 entirely, without having to call out the local weights and measures official.

The following are illustrative examples of the present invention. The features and concepts in each example are there to serve as possible ways in which the present invention can be enacted. It is envisaged that the present invention may be enacted using various combinations of the features described from any of the following examples.

Figure 1 shows an example of a weighing scale 4 incorporating the weighing scale calibration device 2 of the present invention. The weighing scale calibration device 2 in this example comprises a GPS system 8 and control means 10 to facilitate the aforesaid calibration functions including to determine the gravitational constant g' from the location data obtained from the GPS system 8 and automatically calibrate the scale. The control means 10 include hardware such as one or more memory storage devices, one or more processor devices and other electronic circuitry operative to provide the calibration functions of the present invention. The control means 10 may optionally include software modules residing in permanent or removable memory devices operative to provide at least some of the aforesaid calibration functions. Such software modules may include databases and gravitational calculation modules.

The GPS system 8 acts to pinpoint the location of the scale 4 via satellite signals. Once the calibration device 2 has successfully pinpointed the location of the weighing scale, it then proceeds to calculate an updated value of gravitational constant g'. This may be accomplished via a calculation or a look up table on an internal or any other suitable means to determine the required gravitational constant value g'. The weighing scale 4 can then use the updated value of gravitational constant g' in its future and subsequent measurements.

Figure 2 shows a weighing scale calibration system 12 comprising a weighing scale 4 and a portable calibration unit. The portable calibration unit 6 comprises at least part of the weighing scale calibration device 2. In this example the portable unit 6 comprises a GPS system 8 operable to obtain location-based data and the control means 10 to determine gravitational constant g'. However it may be equally viable in an alternative to this example that the control means 10 to determine gravitational constant resides in the scale 4 whilst the GPS system 8 or other automatic location obtaining means reside in the portable calibration unit. In this example, the location data is obtained over secure communications. The secure communications may be effected by any software, hardware or technique that verifies that the handheld unit 6 can be legitimately used by non-authorised or non-appointed calibration personnel.

The person uses the portable calibration unit 6 to automatically obtain the location data.

The person then interfaces the portable calibration unit 6 with the weighing scale 4 in order to transfer the location data and/or gravitational constant data to the weighing scale.

The interfacing may be accomplished by a variety of means and methods. These methods could include, but are not limited to, cable transfer such as Universal Serial Bus (LJSB), wireless transfer such as Bluetooth�, infrared or other wireless communication means and protocols. The portable calibration unit 6 may be a PDA or other portable handheld device with wireless communication access. Alternatively as shown in figures 3a and 3b, the portable calibration unit 6 may be designed specifically for weighing scale calibration purposes, and may have a physical interface 14 pluggable into a scale 4 comprising a complimentary physical interface 16 to that of the portable unit.

By having a portable calibration unit 6 that automatically obtains location-based information, a person using the portable calibration unit 6 may calibrate the scale 4 more quickly than using conventional methods. This may reduce or negate completely the duration of an appointed persons time at the site of the weighing scale, thus reduces the costs associated with performing a single calibration.

Having a portable calibration unit 6 with means to automatically obtain location data is also advantageous in situations where a weighing scale 4 has been moved to a new location in which there exists no wireless or cabled communication access. For example, in a large heavily clad building devoid of any cabled or wireless communication access.

In this particular situation a GPS 8 or other communication device on the scale 4 would 1 6 be unable to obtain the required location data necessary for recalibration. As weighing scales or other weighing instruments may be heavy and cumbersome they may be difficult to move to another immediate geographical position where GPS signals are available in order to perform a recalibration of the gravitational constant g'. The chances of the scale 4 being dropped or damaged are therefore increased if the scale 4 has to be moved each time a calibration is required. Furthermore, such a location may be outside the building, in which case the scale 4 may be subjected to adverse weather conditions while it is obtaining the location data. Such weather conditions could damage the scale.

The person carrying the portable calibration unit, in this instance, would therefore take the reading of geographical location with the portable calibration unit 6 at a sufficiently close point to the weighing scale 4 that allows for the obtaining of the location data. This would be, for example outside of the building where a GPS or other wireless signal could be transmitted and received.

Once the person obtains the sufficiently accurate proximate value of location, the person then enters the building to interface the portable calibration unit 6 with the scale 4 and automatically update the gravitational constant. Such a portable calibration unit 6 may also be useful in a similar situation where a weighing scale 4 fitted with a communication means according to the present invention is in a location devoid of communication access and requires recalibratidn at the same site.

Figure 4 shows another example of where a scale 4 comprises the weighing scale calibration device 2 of the present invention. The weighing scale 4 in this example is primarily powered via a mains electricity cable connection. The weighing scale 4 comprises a GPS system 8 similar to that described and shown in figure 1. The weighing scale 4 in this example further comprises a motion sensor 18, an internal power source 20 and control means 22. The internal power source 20 may also be attached to the weighing scale 4 and is primarily used to provide power to the GPS system 8 when primary power 24 from mains electricity is not available. This internal power source 20 is typically, but not limited to, a battery. The scale 4 may have provisions for trickle charging 26 the battery by the primary power source 24 during normal operation.

The motion sensor 18 is internal or attached to the veighing scale 4 and may also be powered by the internal power source 20 or another separate or dedicated power source distinct from the primary power source 24. The motion sensor 18 is operative to detect motion of the weighing scale 4 for example when the scale 4 is being carried or moved.

Such a sensor 18 may comprise a Micro Electrical Mechanical device or other stability or relative motion sensing device.

The control means 22 in this example may comprise, but is not limited to, features such as hardwired driving circuitry, one or more processors, one or more memory devices and software. The control means 22 are operative to control and facilitate the functional aspects of the present invention in this example.

In this example, the weighing scale 4 and its associated components are set up to automatically obtain GPS location data when the scale 4 is being moved. Normally the GPS system 8 obtains operational power from the primary power source 24. Typically when a scale 4 is relocated to another site, the mains cable is unplugged and the scale 4 is picked up and transferred to the new site. In this example of the present invention, when the scale 4 is unplugged or otherwise cut off, the control means 22 sets the weighing s,cales to an unplugged state'. When in the unplugged state' the control means 22 monitors signals from the motion sensor 18 in order to detect whether or not the scale 4 is being moved. The control means 22 also routes power so that the internal power source 20 provides power to the GPS system 8 so that the GPS system 8 is set to obtain updates of location data whilst the scale 4 is in the unplugged state'. The control means 22 may achieve this in a number of ways.

One way is to continually update relocation information based on periodically activating the GPS system 8 to obtain periodic samples of location data with time. When in the unplugged state', the control means 22 waits for a signal from the motion sensor 18 indicating that the scale 4 has been or is being moved. Once both the conditions of movement and unplugged state' are present, the control means 22 then activates the GPS system 8 to periodically obtain location-based data. In this manner the weighing scale 4 automatically updates its value of gravitational constant whilst being moved until the primary powr source 24 is once again applied to the weighing scale.

The control means 22 may additionally signal the UPS system 8 to obtain location-based data or may increase the frequency of the periodic sampling of location when further motion is detected by the motion sensor 18. Increasing the periodic sampling or providing additional values of location when the motion sensor 18 is triggered, allows the weighing scale 4 to advantageously obtain updated location data during periods of high movement, such as when a delivery vehicle has stopped and a delivery person is removing the scale 4 from the vehicle to take to the new site.

When the scale 4 is finally located and deployed at the new building and the primary source is re-applied to the weighing scale, the GPS system 8 is activated in order to obtain the new location data. Where no GPS signal is available in the new building, the control means 22 then proceeds to take the last known value of location data to be. the correct value of geographical location for gravitational constant determination and then recalibrates the scale. Because the last value was the value taken immediately outside the building when the scale 4 was being moved, the gravitational constant g' calculated would be accurate to the immediate proximity of the final scale 4 location.

Alternatively, the weighing scale 4 may obtain its GPS location data only when the motion sensor 18 is tripped when the scale 4 is in the unplugged state'. In this alternative, internal power source 20 power is conserved and the GPS system 8 only operates to obtain location information when the weighing scale 4 is being moved, for example when a removal person is carrying the scale 4 into the new building. Again, once in the building, if the weighing scale 4 cannot then obtain a GPS positional reading, it then reverts to its last taken positional reading. This last positional reading would be the reading taken from the last detected movement of the motion sensor 18 such as the geographical location immediately outside of the new location which was taken when the removal person started to pick up and remove the scale 4 from the delivery vehicle. As such, the last obtained values of location data would be suitable for using as a gravity zone to calculate the new updated gravitational constant g'. The weighing scale 4 in this exampl therefore automatically recalibrates the scale 4 for the gravitational constant g' without the need for an authorised person even when GPS signals are unobtainable at the new location.

By having the condition that both the primary power source 24 and movement be required in order to activate the GPS system 8, the weighing scale 4 does not unnecessarily recalibrate for gravitational constant g' when there has been a power cut or when someone accidentally knocks the weighing scale. This condition for GPS activation is one possible arrangement within the scope of the present invention. It may be required that other GPS activation conditions are manually, automatically or permanently set for the scale.

Furthermore the control means 22 may activate the GPS system 8 only when the motion sensor 18 has been tripped a number of times or has detected sustained weighing scale 4 movement over a specific period of time. In this maimer the weighing scale 4 does not unnecessarily recalibrate itself when someone unplugs the scale 4 from the primary source and moves it to a different location within the same building.

It is also further envisaged with this example that a weighing scale 4 comprising the calibration device 2 of the present invention is not primarily powered by mains electricity. In such a situation the control means 22 may activate the GPS system 8 to update location data just based upon detection of movement from the motion sensor 18.

In all of the above examples, the GPS system 8 may equally be replaced by or have additional communication devices capable of updating location data, such as mobile phone technology or other suitable wireless devices.

Claims

Claims 1. A weighing scale calibration device comprising means to automatically obtain location data and determine a value of gravitational constant from the obtained data.
2. A weighing scale calibration device as claimed in Claim 1 wherein the means to obtain location data comprises a communications device.
3. A weighing scale calibration device as claimed in Claims 1 or 2 wherein the communications device comprises a GPS system.
4. A weighing scale calibration device as claimed in any of Claims 1 to 3 further adapted to automatically calibrate a weighing scale.
5. A weighing scale comprising the weighing scale calibration device as claimed in any preceding claim.
6. A weighing scale as claimed in Claim 5 further comprising a motion sensor, an internal power source and control means.
7. A portable calibration unit comprising the weighing scale calibration device as claimed in any of Claims ito 4.
8. A portable calibration unit as claimed in Claim 7 further comprising means to interface with and at least partially automatiáally calibrate a weighing scale.
9. A portable calibration unit as claimed in Claims 7 or 8 wherein the unit comprises secure communication means.
10. A portable calibration unit as claimed in any of Claims 7 to 9 wherein the unit is any of a PDA, a mobile phone, any other portable handheld communication device.
11. A weighing scale calibration system comprising: I) the portable calibration unit as claimed in any of Claims 7 to 10 and, II) a weighing scale.
12. A method of calibrating a weighing scale comprising the steps of: I) automatically obtaining location data, II) determining a value of gravitational constant from the location data, II) calibrating a weighing scale using at least the value of gravitational constant.
13. A method of calibrating a weighing scale as claimed in Claim 12 wherein the location calibration data is obtained using a communications device.
14. A method as claimed in Claim 13 wherein the location data is obtained using a portable calibration unit with a GPS system.
15. A method as claimed in Claims 12 or 13 wherein the location data is obtained from a GPS system in the weighing scale.
16. A method as claimed in Claim 15, further comprising the steps of: I) detecting motion of the scale with an internal motion sensor; II) providing power to the GPS system using an internal power source; III) operating the GPS system to obtain location based information.
17. A method as claimed in Claim 16, further comprising the step of; I). detecting a cut off of a scale primary power source;1
18. A weighing scale, portable calibration unit or weighing scale calibration system substantially as described with reference to or as shown in the drawings.Amendments to the claims have been filed as follows 1. A portable calibration unit for calibrating a weighing scale comprising: means to obtain location data; means to interface with the weighing scale; and, means operative to verify that the portable calibration unit can be legitimately used.2. A portable calibration unit as claimed in claim I further comprising means to determine a value of gravitational constant from the obtained location data.3. A portable calibration unit as claimed in Claims I or 2 wherein the means to obtain location data comprises a communications device.4. A portable calibration unit as claimed in Claim 3 wherein the communications *...*1:15 device comprises a GPS system. *.. . * * ****5. A portable calibration unit as claimed in any of Claims I to 4 further adapted to automatically calibrate a weighing scale.**20 6. A portable calibration unit as claimed in any preceding claim wherein the unit is *\ any of a PDA, a mobile phone, any other portable handheld communication device.7. A weighing scale calibration system comprising: I) the portable calibration unit as claimed in any preceding claim and, II) a weighing scale.8. A method of calibrating a weighing scale comprising the steps of: I) obtaining location data with a portable calibration unit; II) interfacing the portable calibration unit with the weighing scale; Ill) verifying that the portable calibration unit can be legitimately used.9. A method of calibrating a weighing scale as claimed in claim 8 further comprising the step of obtaining location data over secure communications.10. A method of calibrating a weighing scale as claimed in claims 8 or 9 further comprising the step of transferring the location data to the weighing scale.11. A method of calibrating a weighing scale as claimed in Claims 8 or 9 further comprising the steps of: determining a value of gravitational constant from the location data with the portable calibration unit; and, transferring the location data to the weighing scale.12. A method of calibrating a weighing scale as claimed in any of Claims 8-1 1 :15 wherein the location data is obtained using a GPS system.* S. S * * S...*:::* 13. A portable calibration unit or weighing scale calibration system substantially as described with reference to or as shown in the drawings. S...I * S **