NZ537027A - Improved weighing apparatus - Google Patents

Abstract

An apparatus for measuring the weight of at least one animal includes a single platform adapted to be walked over by each individual animal, and at least one load sensing means adapted to sense the load applied to the platform. The apparatus is further adapted to output first and second load signals indicative of the load applied. The load sensing means includes at least one strain gauge and includes two paired sets of individual load cells. A position determining means determines when an individual animal only is positioned on the platform and a weight determining means determines the weight of the individual animal positioned on the platform.

Description

^ 11OZ] Intellectual Property Office of N.Z. 2 3 DEC 2005 RECEIVED PATENTS FORM NO. 5 Fee No. 4: $250.00 PATENTS ACT 1953 COMPLETE SPECIFICATION After Provisional No: 537027 Dated: 3 December 2004 IMPROVED WEIGHING APPARATUS WE GALLAGHER GROUP LIMITED, a New Zealand company of Kahikatea Drive, Hamilton, New Zealand, hereby declare the invention for which I/We pray that a patent may be granted to me/us, and the method by which it is to be performed to be particularly described in and by the following statement: 1 IMPROVED WEIGHING APPARATUS TECHNICAL FIELD This invention relates to weighing apparatus and in particular, though not solely, to weighing apparatus adapted to weigh animals, and more particularly, livestock.

BACKGROUND ART Conventional methods for weighing livestock involve the physical capture of the animal to be weighed in a weigh box so that the animal is stationary, thereby enabling load cells associated with the weigh box to estimate the stationary animal's weight. Typically, weighing algorithms are utilised to average the output of an arrangement of 10 load cells associated with the weigh box. The actual weight may be derived from the load versus time signal output by the load cells.

However, although static weighing of animals is the predominant methodology presently used for determining weight, there are a number of drawbacks associated with this approach. For example, such systems typically rely heavily on the constant 15 interaction of personnel with the weigh system to ensure animals are correctly processed. Furthermore, such personnel will often be required to actuate entry and exit gates allowing animals to enter and exit the weigh system appropriately. Consequently, the use of such systems are prone to low animal through-put due to the stop-start nature of weighing process. As a result there is increasing interest in 20 weighing systems which are configured to weigh animals as they progressively move across a given point.

Advantages of weighing animals as they move include the increased animal throughput (compared with static weighing systems) and increases in labour saving since there is no requirement to physically capture animals in weigh boxes. 2 One such approach to measuring moving livestock, or livestock in a free flow situation, has been the provision of a single platform comprising four or less load cells, where each load cell is mounted at a respective corner of the platform. As livestock move over the platform an associated computer system converts the weight 5 versus time signals from the various load cells into an estimate of the animal's weight. This system suffers from the drawback that it is difficult to establish when a single animal only is supported on the platform.

As the weight estimation process requires that only one animal is supported on a weigh platform at one time independent sensor devices (such as "magic eyes") were 10 developed to provide such a determination. Although these devices provide a useful means of determining whether an animal is on the platform it is difficult to deduce, using these devices, whether the animal has all four feet on the platform. Such devices include the use of transducers such as infra red emitters and detectors, ultrasonic position detectors and micro-switch position detectors. However, these 15 devices are prone to damage and being covered in animal waste or other materials which reduces their ability to operate correctly. Moreover, these devices are expensive.

Further approaches to ensuring that only a single animal is supported on a weigh platform at one time have included the incorporation of a swinging bar or other 20 mechanical separation means in the run or race through which the animals pass on their way to the weigh platform. Such separation devices are designed to minimise the chances of multiple animals being present simultaneously on the weigh platform during weighing, therefore enabling the system to produce more accurate results. However, such devices add mechanical complexity to weigh systems and are easily 25 damaged. The use of these devices also requires a significant "training period" (for the livestock) while the livestock familiarise themselves with the device. 3 It is therefore an object of the present invention to provide a weighing apparatus which goes at least some way towards overcoming the above disadvantages or to at least provide the industry with a useful choice.

All references, including any patents or patent applications cited in this specification 5 are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission 10 that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive 15 meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process.

It is an object of the present invention to address the foregoing problems or at least to 20 provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION Accordingly, in a first aspect the invention may broadly be said to consist of an 25 apparatus for measuring the weight of at least one animal including: 4 a single platform adapted to be walked over by each individual animal, and at least one load sensing means adapted to sense the load applied to the platform and being further adapted to output first and second load signals indicative of the load applied, and a position determining means which in response to the first and second load signals determines when an individual animal only is positioned on the platform, and a weight determining means which in response to the first and second load signals determines the weight of the individual animal positioned on the platform.

Preferably, the length of the platform is sufficient to ensure that the entire weight of an 10 individual animal is solely supported at some time.

Preferably, the load sensing means includes at least one load cell.

In some instances the load sensing means may include at least one strain gauge.

Preferably, the load sensing means includes two pairs of individual load cells.

Preferably, the first pair of load cells are positioned near one end of the platform and 15 the second pair of load cells are positioned near the end of the platform opposite the first pair of load cells.

In a further preferred embodiment the first load signal may be provided by said first pair of load cells positioned near one end of the platform, and the second load signal may be provided by the second pair of load cells positioned near the opposite end of 20 the platform to the first pair of load cells.

Preferably, a load may be detected as being applied to the weighing platform when the first and/or second load signal rises above a predetermined threshold value.

Alternatively, a load may be detected as being applied to the weighing platform when the rate of rise of the first and/or second load signal rises above a predetermined rate of rise threshold value.

Preferably, the weight determining means is adapted to determine the weight of an 5 animal by applying an averaging function to the first and the second load sensing signals between a first and a second time.

Alternatively, the first and the second load signals output by the load sensing means may be combined and the combined signal utilised to determine the weight of an individual animal.

Preferably, a load is detected as being removed from the platform when the first and/or second load signal output by the sensing means drops below a predetermined threshold value.

Alternatively, a load is detected as being removed from the weighing platform when the rate of fall of the first and/or second load signals output by the sensing means 15 falls below a predetermined rate of fall threshold value.

Preferably, said predetermined threshold values are adjustable.

In a second aspect the invention may broadly be said to consist in an apparatus for measuring the weight of at least one animal including: first and second distinct platforms aligned in series in the direction of movement of the 20 at least one animal and arranged in such a way that each animal is required to walk over each of the two platforms in turn, and a load sensing means adapted to sense a load applied to each of the first and second platforms, said load sensing means being further adapted to output first, second and third load signals, wherein said first load signal is indicative of a load being applied to 6 the first platform, and wherein said second and said third load signals are indicative of the load applied to the second platform, and a position determining means which in response to the first, second and third load signals determines when an individual animal is on the second platform, and weight determining means which in response to the second and third signals determines the weight of the individual animal on the second platform.

Preferably, the length of the second platform is sufficient to ensure that the entire weight of an individual animal is solely supported at some time during that individual animal's passage across the second platform.

Preferably, the load sensing means includes load cells.

Preferably, at least one load cell is associated with the first platform and at least two pairs of load cells are associated with the second platform.

Preferably the first and second load signals used may indicate a force or forces applied to a platform. Those skilled in the art should appreciate that such force 15 indications may be representative of weight, but may also include components contributed from the movements or actions of an animal.

Preferably, the weight determining means determines the weight of an individual animal by applying an averaging function to the second and third load signals between a first and a second time when two platforms are provided.

Alternatively, the second and third load signals may be combined and the combined signal utilised to determine the weight of an individual animal.

Preferably, a load is detected as being removed from the first platform when the first load signal drops below a predetermined threshold. Alternatively, a load may be 7 detected as being removed from a platform when the first load signal experiences a threshold rate of change.

Preferably, a load is detected as being removed from the second platform when the second load signal and/or the third load signal drops below a predetermined threshold 5 value. Alternatively, a load may be detected as being removed from the second platform when the second load signal and/or the third load signal experience a threshold value rate of change.

Preferably, said predetermined threshold values are adjustable over time.

Preferably the present invention may be adapted to weigh quadruped animals. In 10 such instances the present invention may be used to determine or detect the time at which a step on event occurs and preferably the time at which a step off event occurs for a platform.

Preferably a step on event may be detected by a leading load cell or cells of a platform where two rising slopes in the output signals obtained indicate the animal's 15 front and rear legs stepping on to the platform.

Preferably a step off event may be determined by the trailing or rear load cell or cells of a platform where the two falling slopes represented in the output signal or signals of such a load cell or cells indicate the front and rear legs of an animal stepping off the platform.

Preferably weighing information may be considered by the weight determining means in the time period between detected step on and step off events.

Preferably the output signals of the load sensing means identified between step on and step off events may be analysed by at least one variance function. Such a variance function can indicate within this period of time a further subset of time in 25 which an animal is moving the least. In this subset time period the signals of the load 8 sensing means will be predominantly indicative of the weight of the animal, not force applied by the animal through movement.

Preferably once a minimal variance time period is identified between step on and step off events the output signal or signals of the load sensing means may be supplied to 5 an averaging function to in turn indicate the weight of an animal currently on the platform.

In a preferred embodiment the apparatus provided may include an electronic identification system. This electronic identification system may be employed to associate a unique identifier particular to an animal with a weight determined in 10 conjunction with the present invention.

Furthermore in some instances an electronic identification system could also be used to assist the position sensing means in determining the position of the animal. For example in the case of RFID tags a maximum return signal strength for the tag reader close to the centre of a platform may assist in determining that the animal is in turn 15 located near the centre of the platform.

BRIEF DESCRIPTION OF DRAWINGS Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which: Figure 1 is a schematic diagram showing the weighing apparatus formed in accordance with a preferred embodiment of the present invention; Figure 2 is a graph showing the weight or force output versus time signal produced by a first pair of load cells as a single animal walks 25 across the weighing apparatus of Figure 1; 9 Figure 3 is a graph showing the weight or force output versus time signal produced by a second pair of load cells as a single animal walks across the weighing apparatus of Figure 1; Figure 4 is a schematic diagram showing the weighing apparatus formed in accordance with an alternative embodiment of the present invention; Figure 5 is a flow diagram showing the steps in an algorithm adapted to compute the position of an animal on the weighing apparatus of Figure 1; Figure 6 is a flow diagram showing the steps in an algorithm adapted to compute the position of an animal on the weighing apparatus of Figure 4; Figure 7a. 7b. 7c show in schematic form the actions of an animal when stepping onto, standing on and subsequently stepping off from a platform 15 provided in accordance with present invention.

BEST MODES FOR CARRYING OUT THE INVENTION With reference to Figure 1, a weighing apparatus formed in accordance with a preferred embodiment of the present invention will now be described. In preferred embodiments the weighing apparatus 1 is adapted to measure the weight of animals, 20 and more particularly, livestock.

Reference throughout this specification will now be made to the weighing apparatus 1 being adapted to measure the weight of animals, such as livestock. However, in alternative embodiments the present invention may be also used to measure the weight of other animals, not being livestock, such as domestic animals or humans. 25 Accordingly, reference throughout this specification to the weighing apparatus 1 being particularly adapted to measure the weight of livestock should in no way be seen a limiting.

Weighing apparatus 1 includes a single platform 2 which is adapted to be walked over by each individual animal. An animal run or race may be used to guide or effectively 5 control the passage of the animal across the platform 2. In order to steady the flow of animals through the race and further prevent livestock running and jumping through the race a curve or a rod or bar may be fitted in or to the race.

Accordingly, the length of the platform 2 should be sufficient to ensure that the entire weight of each animal being weighed is capable of being supported at one time.

The weighing apparatus 1 includes at least one load sensing means which is configured from individual load sensing devices 3a and 3b (hereinafter referred to as load sensing means 3) which are positioned proximately with respect to the platform 2. The load sensing means 3 is adapted to sense the load applied to the platform 2 and output signals indicative of the load applied. In alternative embodiments any 15 number of load sensing devices may be associated with the weighing apparatus and be adapted to detect when a load is applied to the platform 2.

Accordingly, as individual livestock walks across platform 2 the load sensing means 3 will output load signals indicative of the load being applied by the weight of the livestock on the platform 2.

The load sensing means 3 may be formed from any number of a variety of different load sensing devices such as load cells or strain gauges.

Reference throughout this specification will now be made to the load sensing devices 3a and 3b each being formed from a pair of load cells, however this should in no way be seen a limiting. For the purposes of this specification a load cell may be defined 25 as a device adapted to convert a weight or force applied to it into electrical signals 11 which can be used to actuate or drive a measuring or control apparatus. The weight of an animal may be determined from the electrical signals output by the load cells associated with the platform upon which an animal walks. For example, the resistance of the load cell may change with weight.

In a preferred embodiment a first pair of load cells form load sensing device 3a and are positioned near one end of the platform 2 (corresponding to an entry point onto the platform). A second pair of load cells form load sensing device 3b and are positioned at the end of the platform opposite the first pair of load cells (thus corresponding to an exit point from the platform). The load sensing devices 3a and 3b are adapted to output first and second load signals respectively, and each load signal is indicative of the load applied to the platform 2.

Also associated with the load sensing devices (3a) is a signal transfer line (8) which is connected to a processing means (4). A further signal line (9) is also connected to the load sensing devices (3b) and the same signal processing means (4).

Also included, but not shown, is a position determining means which is configured to receive as input the first and second load signals from the load sensing means 3 and subsequently apply an algorithmic function to these signals (using processing means 4) to determine when a single animal is positioned on the platform 2. Such processing means may be formed as or utilise a computer system.

For the purposes of the foregoing description those skilled in the art should appreciate that a computer system may be formed from a programmable logic unit or other processing device on which computer software may be run. Computer software may be defined as a set of instructions able to be interpreted by a computer system and capable of performing a task.

A computer system loaded with appropriate computer software may be employed to process the signals output by the load sensing means to determine when a single 12 animal is positioned on the platform 2. Those skilled in the art will appreciate that computer hardware loaded with appropriate software can be used to receive, codify and translate a variety of information formats (such voltage signals from a load cell) into position information.

Also included (but not shown) in the weighing apparatus 1 is a weight determining means which in response to the load detected by the load sensing means 3, and more particularly, the first and second load signals output by the load sensing devices 3a and 3b, determines the weight of the individual livestock. The weight determining means may also be formed as a computing or processing system (such as 10 processing means 4) which is adapted to receive and process the load signal or signals transmitted from the load sensing means 3 and then convert those signals into a weight value using known signal processing techniques. For example, the actual weight of an individual head of livestock may be determined from output load versus time data (which may optionally be recorded), where the load applied to the 15 platform may be output from the load sensing means as a voltage value.

Specifically, the weight determining means, in response to the load detected on platform 2, determines the weight of the individual livestock. In such an embodiment the position determining means may provide an initial indication, such as a position signal, of when the weight of an individual head of livestock being weighed is 20 supported solely and fully by the platform 1. Subsequent to such a position signal being received the weight determining means may proceed to conduct some form of signal processing on the first and second signals generated by the load sensing means 3 to determine the weight of the individual livestock on the platform 1.

The weight value may be determined as the average of the first and the second load 25 signals output by the load sensing means 3 between a first and a second or subsequent time. Alternate signal processing or filtering means may be applied to the 13 first and second load signals to deduce the weight on the platform during the time period or interval defined by the first and the second time.

The above process may be enhanced by the inclusion of data from electronically identified (EID) animals where the data is recorded with the weight data of the 5 livestock. The system may be used with, or without EID. EID does however assist and enhance the utility of the system.

In an alternative embodiment, the weight of an individual head of livestock may preferably be determined by a combination of outputs of the individual load sensing means associated with each platform. In such an embodiment the weight of 10 individual livestock may be calculated from the combination (for example, the sum) of the first and second load signals output by the load sensing means 3.

It should be appreciated that a load (and hence an animal) is detected as being removed from the platform when the first and/or second load signal output by the load sensing means drops below a predetermined threshold value and/or exceeds a 15 threshold rate of change value, wherein said predetermined threshold values are adjustable. The use of user adjustable predetermined threshold values will facilitate the correct calibration of the platform in response to, for example, load cell drift. The predetermined threshold value may also be adjustable over time to account for the build-up of waste matter on the platforms.

Figure 4 shows a schematic diagram showing the weighing apparatus formed in accordance with an alternative embodiment of the present invention. The weigh apparatus 5 shown is identical to that depicted in Figure 1 above with the exception that it includes an additional "pre-weigh" platform 6.

In such an embodiment the "pre-weigh" platform 6 (hereinafter referred to as the first 25 platform 6) and a second platform 2 are provided and are aligned in series in the direction of movement (generally indicated by arrow 7) of the individual livestock. The 14 platforms 6 and 2 may be further arranged to force or guide the livestock to walk over the first and the second platform in turn.

Such a first platform 6 is adapted to provide an indication of when an animal is approaching the main weighing platform, being the second platform 2 (which 5 corresponds to the platform 2 shown in Figure 1 above). Associated with the first platform 6 is a load sensing means which includes an individual load sensing device 3c. The configuration, functionality and operation of the second platform 2 corresponds to that of the platform 2 described above with respect to Figure 1. Accordingly, it should be appreciated that there is also associated with the second 10 platform 2 a load sensing means (which is configured from individual load sensing device 3a and 3b), a position determining means, a weight determining means and a processing means 4 which together operate in the manner described above with respect to Figure 1.

The load sensing device 3c is adapted to sense the load applied to the platform 6 and 15 output a signal(s) indicative of the load applied. Accordingly, as individual livestock walk across platform 6 the load sensing device 3c will output a further load signal(s) indicative of the load being applied by the weight of the livestock.

As with the load sensing devices 3a and 3b, the load sensing device 3c may be formed from or include one or more load cells or strain gauges.

Position determining means may also be adapted to process a load signal or signals that have been output by the load sensing device 3c. Such a signal may be processed in conjunction with the first and second load signals output by the load sensing devices 3a and 3b (associated with second platform 2) to determine when a single animal only is completely supported on the second platform 2.

A weight determining means may, in response to the first and second load signals, determine the weight of the individual livestock.

Alternatively a weight determining means may, in response to the first and second load signals output by the load sensing devices 3a and 3b and the further load signal output by load sensing device 3c, determine the weight of the individual livestock.

Figures 2 and 3 show graphs 10 and 20 respectively which depict exemplary force 5 output (along the y-axis) versus time signals (along the x-axis) derived from the use of platform 2 for a single animal walking across the weigh apparatus 1 depicted in Figure 1. The effect of the single animal is illustrated in the wave form trace shown between points 15 and 17 with respect to figure 2 and between points 28 and 27 as illustrated with respect to figure 3.

References 11 and 21 reference in general the waveform shown, being the conversion of the normalised voltage over time for the load applied to platform 2 (that is, the respective outputs from load sensing devices 3a and 3b) into a corresponding weight or (force) signals. Such a conversion may be computed by the weight determining means described above.

Using such load versus time signals the position determining means may determine (using an algorithmic function configured with predetermined threshold values or rate of change values) when a single animal is supported solely by the platform 2. For example, when the signal output by load sensing device 3a is converted to a (force) signal and that (force) signal reaches point 12 (on Figure 2), and the signal output by 20 load sensing device 3b is converted to a weight signal and that weight signal reaches point 22 (on Figure 3), the position determining means may be adapted to deduce that half of a single animal is on the platform 2. However, in alternative embodiments reference points 12 and 22 shown in figures 2 and 3 may not necessarily be employed. For example in other embodiments the rate of change of the wave form 25 shown can be used to indicate whether an animal has stepped off or onto a platform, or alternatively whether an animal is in the process of stepping on or stepping off a platform. 16 In such embodiments a step on event may be determined by two rising slope wave form traces as the front and subsequent rear legs of a quadruped animal mount the platform. Each of these high rates of wave form change events can therefore indicate that an animal is stepping onto the platform.

The same approach may also be taken in such embodiments with respect to step off events where a threshold negative gradient of the wave form shown can indicate that an animal is stepping off the platform.

For example, in such embodiments between the points 16 and 13 when the rate of change of the force signal reaches a predetermined threshold then the position 10 sensing means deduces that the second half of the animal has stepped onto the platform 2.

At the same time the position sensing means analyses the force signal from the trailing force sensing means to determine when there has been a step off of the platform.

The first step off occurs between points 24 and 25 on graph 20 then the second step off occurs between points 26 and 27 of graph 20. These step off events are determined as occurring when the rate of fall of the force signal reaches a predetermined threshold value.

Furthermore, those skilled in the art should appreciate that the threshold values 20 employed are either magnitude measurements or rates of change which may be determined empirically, or alternatively may be provided through a machine learning based system if required.

Accordingly, in some instances the peak amplitude of the first load signal may indicate that an animal has stepped onto the platform 2 and signal processing 17 conducted on the second load signal can be used to verify that only a single animal is on the platform 2.

Similarly, when the signal output by load sensing device 3a is converted to a (force) weight signal and that (force) signal reaches point 13 (on Figure 2), and the signal 5 output by load sensing device 3b is converted to a weight signal and that weight signal reaches point 23 (on Figure 3), the position determining means may be adapted to deduce that a single animal is completely on the platform 2.

Finally, when the signal output by load sensing device 3b is converted to a (force) signal and that (force) signal reaches a rate of fall shown between points 24 and 25 10 the position determining means may be adapted to deduce that a single animal's first half has stepped off the platform.

Alternatively when magnitude values as opposed to rates of change are considered identification of reference point 14 on figure 2 and reference point 24 on figure 3 may in some instances indicate that a single animal is currently stepping off the platform 15 provided.

Figures 7a, 7b and 7c show in schematic form the actions of an animal when stepping onto, standing on and subsequently stepping off from a platform provided in accordance with present invention. As can be seen from these figures a quadruped animal will initially place their front set of legs on a platform at one time, and then 20 subsequently mount the platform with their rear legs. When stepping off the platform the same quadruped animal will again lead with their front legs and step off last with their rear legs. This will in turn lead to two distinct wave form traces being recorded in conjunction with the present invention which may be employed to determine the position of the animal as shown with respect to figure 7b. 18 The weight determining means processes data collected from the force signals from both force sensing means 3a and 3b over the time between the points'! 3 on figure 2 and 24 on figure 3 to determine the weight of the animal.

Through that period where the animal is known to be on the platform a function of 5 least variance is applied to the combined signals to determine a stable region of signals through that period. An averaging function is then applied to signals from 3a and 3b for that period and a weight derived for the animal for that weighing event The weight determining means may subsequently proceed to process the load signals 11 and 21 between the time periods corresponding to the points marked 23 and 24 10 (on Figure 3) to calculate the weight of the animal on the platform. Such processing may involve the application of least variance algorithms to determine a period of time within the time that the animal is solely supported by the platform where the force sensing signals are most stable. An averaging function is then applied to the data of this period to calculate the weight of the animal for this weighing event the weight 15 signal 21 between specific time periods.

The flow diagram 30 depicted in figure 5 shows the steps in an algorithm which can be implemented in computer software and used to compute the position of an animal on the platform 2. Such an algorithm may take on input the signals from the load cells incorporated in load bars supporting the platform 2.

Initially, a weight data buffer is zeroed in preparation to receive a new reading.

A signal from the leading (or front) load cell is analysed to determine whether the leading edge of the signal exceeds a predetermined threshold. Such a signal would indicate that an animal has stepped onto the front of the main weighing platform.

The signal from the trailing (or rear) load cell is analysed in conjunction with the signal 25 from the leading load cell such that when both reach a predetermined threshold the 19 processing means determines whether the position of the animal to be weighed is solely and entirely supported on the main weighing platform.

The signals from the leading and trailing load cells of the main weighing platform are then gathered and recorded in a data buffer.

The position sensing means in conjunction with the position sensing algorithm monitor the trailing load cells signal such that when the signal falls below a falling edge threshold the position sensing means in conjunction with the position sensing algorithm determines that the animal is stepping off the weighing platform.

At this time the signals being recorded for determining the weight of the animal are no 10 longer being collected and an averaging function is applied to this signals collected and a weight is recorded for that particular animal.

In instances in which RFID devices are being used then the weight data may be recorded along with the RFID data associated with the animal being weighed.

Finally, the weight data buffer is zeroed and the cycle may be repeated for each 15 separate animal that walks onto the platform to be weighed.

The flow chart 31 depicted in figure 6 shows the steps in an algorithm which can be implemented in computer software and used to compute the position of an animal on platform 2. Such an algorithm may receive as input the signals from the load cells incorporated in load bars supporting the platforms 2 and 6.

Such an algorithm may be adapted to process the independent signals from the load cells associated with the pre-weigh platform in conjunction with the front and rear load cells associated with the main weighing platform. Such signals may be used to determine the position of an animal with respect to the main weighing platform for the purpose of weighing each animal.

Initially, a weight data buffer is zeroed in preparation to measure the weight of a new animal that is approaching the weigh platform 6.

The signal output from load cells associated with the pre-weigh platform are analysed to determine whether they exceed a predetermined threshold. Such signals may 5 indicate that an animal has stepped onto the pre-weigh platform.

The signal output from the front load cell associated with the main weighing platform is analysed to determine whether the leading edge of the signal exceeds a predetermined threshold, which indicates that an animal has stepped onto the front of the main weighing platform.

The signal from the rear load cell associated with the main weighing platform is analysed in conjunction with the signal from the front load cell of the main weighing platform. When both signals reach a predetermined threshold and the signal from the pre-weigh platform falls below a predetermined threshold the processing means determines that the position of the animal to be weighed is solely and entirely 15 supported on the main weighing platform as there is a gap between the currently supported animal and the next animal to be weighed.

From this time the signals generated by the front and rear load cells of the main weighing platform are gathered and recorded in a data buffer.

The position sensing algorithm monitors the rear load cell signal output by the main 20 weighing platform such that when that signal falls below a falling edge threshold or rate of fall, the position sensing algorithm senses that the animal is stepping off the weighing platform.

At this time the signals from the load sensing means are no longer used for weight determination but are still processed for position sensing. An averaging function is 25 applied to those signals collected and recorded for that particular animal. 21 If RFID devices are being used then the weight data is recorded along with the RFID data associated with the animal being weighed.

Finally, the weight data buffer is zeroed and the cycle repeated for the next animal to be weighed.

The present invention provides many advantages over prior art weighing apparatus.

The provision of a weighing apparatus which is adapted to separate load signals corresponding to entry and exit points on a weigh platform, and subsequently use such signals to determine an animals position on that platform is of advantage.

The provision of a weighing apparatus that is easier and more cost effective to 10 manufacture, set-up and maintain compared to prior art weighing apparatus is advantageous.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims. 22

Claims (2)

WHAT WE CLAIM IS:

1. An apparatus for measuring the weight of at least one animal which includes:

a single platform adapted to be walked over by each individual animal, and at least one load sensing means adapted to sense the load applied to the platform and being further adapted to output first and second load signals indicative of the load applied, where a load sensing means includes at least one strain gauge and includes two paired sets of individual load cells, and a position determining means which in response to the first and second load signals determines when an individual animal only is positioned on the platform, and a weight determining means which in response to the first and second load signals determines the weight of the individual animal positioned on the platform.

2. An apparatus as claimed in claim 1 wherein the length of the platform is sufficient to ensure that the entire weight of an individual animal walking over the platform is solely supported at one time.

3. An apparatus as claimed in claim 1 or claim 2 wherein the load sensing means includes at least one load cell.

4. An apparatus as claimed in any previous claim wherein the first pair of load cells are positioned near one end of the platform and the second pair of load cells are positioned near the end of the platform opposite the first pair of load cells.

I Intellectual Property Office of fsj.z.

2 ~ OCT 2007

5.

An apparatus as claimed in any previous claim wherein a load is detected as being applied to the platform when the first and/or second load signal rises above at least one predetermined threshold value.

6. An apparatus as claimed in any one of claims 1 to 4 wherein a load is detected as being applied to the platform when the first and/or second load signal rises above at least one predetermined rate of rise value.

7. An apparatus as claimed in any previous claim wherein the first and the second load signals output by the load sensing means are combined to determine the weight of an individual animal.

8. An apparatus as claimed in claim 7 wherein the weight determining means is adapted to determine the weight of an animal by applying an averaging function to the first and the second load sensing signals between a first and a second time.

9. An apparatus as claimed in any previous claim wherein a load is detected as being removed from the platform when the first and/or second load signal drops below at least one predetermined threshold value.

10. An apparatus as claimed in any one of claims 1 to 8 wherein a load is detected as being removed from the platform when the first and/or second load signal exceeds at least one predetermined rate of fall value.

11. An apparatus as claimed in any one of claims 5 to 10 wherein a predetermined threshold value is adjustable.

12. An apparatus as claimed in any previous claim which includes an electronic identification system.

Intellectual Property

Of<ice of At -

24

2 ~ OCT 2007

H 0 p j v c

15.

An apparatus for measuring the weight of at least one animal including:

first and second distinct platforms aligned in series in the direction of movement of the at least one animal and arranged so that each animal is required to walk over each of the two platforms in turn, and a load sensing means adapted to sense a load applied to each of the first and second platforms, said load sensing means being further adapted to output first, second and third load signals, wherein said first load signal is indicative of a load being applied to the first platform, wherein said second and said third load signals are indicative of the load applied to the second platform, and wherein the load sensing means on the second said platform includes at least one strain gauge and includes two paired sets of individual load cells, and a position determining means which in response to the first, second and third load signals determines when an individual animal is on the second platform, and weight determining means which in response to the second and third signals determines the weight of the individual animal on the second platform.

An apparatus as claimed in claim 13 wherein the length of the second platform is sufficient to ensure that the entire weight of an individual animal walking over the second platform is solely supported at one time.

An apparatus as claimed in claim 13 or claim 14 wherein the load sensing means includes at least one load cell.

An apparatus as claimed in any one of claims 13 to 15 wherein the load sensing means includes at least one strain gauge.

25

18.

19.

23.

An apparatus as claimed in any one of claims 13 to 16 wherein at least one load cell is associated with the first platform and at least two pairs of load cells are associated with the second platform.

An apparatus as claimed in any one of claims 13 to 17 wherein the second and third load signals are combined to determine the weight of an individual animal.

An apparatus as claimed in claim 18 wherein the weight determining means determines the weight of an individual animal by applying an averaging function to the second and third load signals between a first and a second time.

An apparatus as claimed in any one of claims 13 to 19 wherein a load is detected as being removed from the first platform when the first load signal drops below a predetermined threshold.

An apparatus as claimed in any one of claims 13 to 19 where a load is detected as being removed from the first platform when the first load signal exceeds at least one predetermined threshold rate of fall value.

An apparatus as claimed in any one of claims 13 to 19 wherein a load is detected as being removed from the second platform when the second load signal and/or the third load signal drops below at least one predetermined threshold value.

An apparatus as claimed in any one of claims 13 to 19 wherein a load is detected as being removed from the second platform when the second load signal and/or the third load signal exceeds at least one predetermined threshold rate of fall value.

An apparatus as claimed in any one of claims 20 to 23 claims wherein a predetermined threshold value is adjustable.

26

25. An apparatus as claimed in any one of claims 13 to 24 which includes an electronic identification system.

26. An apparatus substantially as herein described with reference to and as illustrated by the accompanying drawings and/or examples.

27

[ intellectual Property | Office of 2.

2 ~ OCT 2007

! R E C E ! V 5: 0 ■