The present invention relates to a load-measuring, fleet asset tracking and data management system. In particular, the invention relates to a load-measuring, fleet asset tracking and data management system for load-lifting vehicles and shipping container loaders.
U.S. Pat. No. 4,919,222 to Kyrtsos et al. discloses a dynamic payload monitor for measuring and displaying a payload weight for a loader vehicle. It does so by sensing the hydraulic pressure and position of the lifting arm cylinders. The system includes a calibration step where the operator moves an empty loader bucket through a load cycle. The monitor has a load cycle reset control for specifying the beginning of the load cycle, at which point the operator can reset the calibration data. A first parabolic curve is generated representing curve fitted pressure versus extension data for the empty loader bucket. The calibration process is next repeated for a known weight and a second parabolic curve is generated thereby.
The payload weight is computed by curve-fitting the sensed pressure and position data to a second order polynomial, and then by performing interpolation or extrapolation with the pair of pressure versus position reference parabolas obtained during calibration.
However, the above system may experience weight drift unbeknownst to the operator if a change in the mechanical system occurs. For example, a known weight of 1,200 pounds, that the system previously determined to be weigh 1,200 pounds, may now read as 1,250 pounds. This weight drift may occur through hydraulic leakage in the system, or if one of the cylinders becomes faulty for example. The pressure transducer may also tend to drift over time and need to be reconfigured at various times during its life cycle. Weight and transducer drift may lead to inaccuracies in payload measurements. To minimize this drift, the system may have to be periodically re-calibrated, which may be relatively time consuming.
U.S. Pat. No. 5,082,071 to Kyrtsos et al. discloses a payload monitoring system where pressure versus extension characteristics for a preselected number of discrete known payloads are determined experimentally for the vehicle and stored into memory as curve-fitted second order polynomials. When a load of unknown weight is measured, each data point along the load cycle is compared to the pressure versus extension characteristics of known payloads. The second order polynomial that best fits with these data points is used to determine the weight of the load.
Here too this system may experience weight drift if a change in the mechanical system and/or transducer drift occur. The weight drift and/or transducer drift may affect the curvatures of the pressure versus extension characteristics. This may lead to inaccuracies in payload measurements. To minimize these inaccuracies, this system may have to periodically repeat its experimental storing of a series of preselected numbers of discrete payloads to determine a new set of second order polynomials, which here too may be relatively time consuming.
There is accordingly a need for a system that identifies when a change in the mechanical system and/or a change in the transducer has occurred to signal when re-calibrating the payload monitoring system is required.
The present invention provides a load-measuring, fleet asset tracking and data management system for load-lifting vehicles and shipping container loaders disclosed herein that overcomes the above disadvantages. It is an object of the present invention to provide an improved load-measuring, fleet asset tracking and data management system for load-lifting vehicles and shipping container loaders.
There is accordingly provided a system for monitoring payload for a load-lifting vehicle. The vehicle has a lifting arm and a hydraulic actuator operatively connected to the lifting arm. The system has a means for correlating actuator pressure within the actuator at a set position of the lifting arm with weight for generating a calculated weight of a payload. The system has a means for generating a payload pattern relating actuator pressure to time as the lifting arm moves the payload through a load cycle. The system has a means for comparing the payload pattern with a set pattern relating pressure to time corresponding to the calculated weight of the payload and storing the calculated weight of the payload into memory if the deviation between the patterns is equal to or less than a certain amount.
According to another aspect, there is provided a payload monitoring system for a load-lifting vehicle having a lifting arm and a hydraulic actuator operatively connected to the lifting arm. The system has a means for determining a calculated weight of a payload when the payload is stationary. The system has a means for generating and storing a plurality of set patterns relating actuator pressure to time as the lifting arm moves through a load cycle for a plurality of loads of known weights moved through the load cycle under a plurality of rates of flow of hydraulic fluid passing into and out of the actuator. The system includes a means for generating a payload pattern relating actuator pressure to time as the lifting arm moves the payload through the load cycle and verifying the calculated weight of the payload with one of the set patterns generated from both a load of known weight corresponding to the calculated weight of the payload and a rate of flow of hydraulic fluid passing into and out of the actuator corresponding to that at which the payload was moved through the load cycle.
According to a further aspect, there is provided a method of monitoring payload for a load-lifting vehicle. The vehicle has a lifting arm and a hydraulic actuator operatively connected to the lifting arm. The method includes hydraulically connecting a transducer to the actuator for sensing pressure therein. The transducer converting the pressure into electrical signals related thereto. The method includes positioning the lifting arm in an unloaded state to a set position and determining a first signal from the transducer in the set position. The method includes disposing a load of known weight on the lifting arm, determining a second signal from the transducer while the lifting arm is in the set position, and correlating a relationship between the first signal and the second signal and weight on the lifting arm therefrom. The method includes positioning a payload on the lifting arm, determining a third signal from the transducer while the lifting arm is in the set position, and determining a calculated weight of the payload based on the relationship. The method includes moving the payload through a load cycle at a rate of flow of hydraulic fluid passing into and out of the actuator where the payload is lifted a distance from the set position, measuring signals of the transducer at a series of points along the load cycle, generating a payload pattern based on the series of points, and comparing the payload pattern with a set pattern corresponding to the calculated weight of the payload and the rate of flow of hydraulic fluid. The method includes repeating the above steps if the deviation between the payload pattern and the set pattern is greater than a certain amount.
The invention will be more readily understood from the following description of preferred embodiments thereof given, by way of example only, with reference to the accompanying drawings, in which:
Referring to the drawings and first to
Vehicle 10 has a load-lifting system 27 which includes a pair of lifting arms 28, as best shown in
The load-lifting system 27 has a pair of spaced-apart forks 36, as shown in
The load-lifting system 27 has a pair of fork actuators, in this example, hydraulic actuators 50, as shown in
When hydraulic fluid is added to cylinder 52, rod 54 retracts upwards, causing end 66 of link 60 to raise fork 36 upwards, from the perspective of
The load-lifting system 27 has a pair of arm actuators 68, in this example, hydraulic actuators disposed adjacent to respective sides of the vehicle and of which only actuator 68 is shown. The other of the actuators is on the opposite side of the vehicle and is substantially the same in parts and function and therefore only one actuator will be described in detail. Each actuator 68 has a cylinder 70 and a rod 72 disposed to retract within and extend outwards from the cylinder upon the withdrawal or application of pressurized hydraulic fluid to the cylinder. In this example, cylinder 70 pivotally connects to the vehicle via a pivot pin 74 located adjacent to bottom 20 of the vehicle and spaced-apart from rear 14 of the vehicle. Rod 72 pivotally connects to arm 28 via pivot pin 76, which is spaced-apart from the end 32 of the arm and is disposed adjacent to cab 16.
When hydraulic fluid is added to cylinder 70, rod 72 retracts within the cylinder, as shown in
Vehicle 10 has a load-measuring system 78 which includes at least one transducer and in this example a pair of transducers, one for each arm 28. In this example the transducers are hydraulic pressure transducers and only transducer 80 is shown schematically in
The system 78 also includes a controller, in this example a microprocessor 83, shown in
As the angular position of the arms changes, as indicated by dashes having numeral 84 in
As the vehicle moves through a load cycle along dashes 84, a continuous stream of pressure readings provides a continuous stream of different voltages. The voltage readings correlate to weight readings. In this manner, the weights of a plurality of waste load, or payloads, from a plurality of waste containers may be calculated by the computer and stored within the computer in a dynamic, efficient and continuous manner. This may be referred to as a means for correlating actuator pressure within the actuator at a set position of the lifting arm with weight for generating a calculated weight of a payload.
The weights of given payloads thus calculated may then be communicated via computer 85 to a central corporate office or waste load tracking control center by, for example, wireless or cellular transmission. In this manner, the data from various vehicles and their various accumulated payloads may be acquired and stored within a central, fleet data management system.
The system 78 may be readily used for excavators, for example, which provide a good example of the variety of load dynamics. Excavators' arms may reach out for short or long digging motions depending on the requirements of the task. Weight measurements of a given load will vary based the angle and degree of extension of the arm, causing the load environment to be very dynamic. The more dynamic the environment, the more data is needed from the transducers to determine the reference points and the weight of the load that is being lifted.
This is in contrast to less dynamic systems, such as fork lifts, which may primarily have merely up and down motions. For such vehicles that have a less dynamic environment, fewer transducer readings are needed to determine the relevant reference points and the weight of the load that is being lifted.
As mentioned above, system 78 has a transducer 80 for each of the cylinders 70 in this example. This allows the transducers to send a pair of parallel output signals, which may provide a redundancy in measurements to allow for a margin of error and quality control. Having separate transducers for each arm 28 also enables the computer to determine if one side 29 or 31 of the vehicle 10 and/or container 46 is heavier than the other.
In operation, as arms 28 are angularly displaced, switch 86 sends a signal to the computer 85.1 at every increment at which cylinder 70, in this example, spans an angle equal to the angle α. The computer 85.1 is programmed such that, upon receiving the signal from the switch 86, it records the output of the transducer 80.1 for the given position of the cylinder at this interval. This process is repeated and a series of discrete transducer outputs are stored in the computer 85.1 from which the weight of the waste load may be calculated in a similar manner as described for the embodiment shown in
The computer 85.1 may be programmed such that should switch 86 have operational issues or fail, the computer reverts back to storing continuous output readings of the transducer as described in the embodiment shown in
System 78.1 with its switch 86 may be particularly suited to less dynamic vehicles, such as fork lifts, that do not require as many reference points for determining the weight of a lifted load.
There are five stages for the operator of the garbage truck to follow for system 78.2. Referring to
In the second stage and referring to
In the third stage shown in
In the fourth stage shown in
In the last, optional fifth stage, the operator lowers the container 46 to the ground 26 and reverses the waste disposal vehicle 10. Once the forks 36 are free from the sleeves of the container, as shown in
From the fourth output, the computer may determine a second zero-weight reading. One or more of the above stages may be referred to as a means for correlating actuator pressure within the actuator at a set position of the lifting arm with weight for generating a calculated weight of a payload. In theory, the first zero-weight reading determined from the first stage should be equal to the second zero-weight reading determined from the fifth stage. This last step is important for assessing consistency between readings. The extent to which the first and second zero-weight readings differ provides an indication of the margin of error between calculations. The computer may be programmed to take the average of the first and second zero-weight readings when determining the weight of the waste load. The computer may also, for example, be programmed to disregard one of the first and second zero-weight readings if said one of the readings differs too greatly from a predetermined threshold.
In a further variation, instead of button 88, a switch, such as switch 86 shown in
In a like manner as described before, the differences in milliamp outputs from the load cells for adjacent angular positions are the same for a given waste load, regardless of vehicle loads or fork position. Thus, the weight of waste load may be determined from the load cells readings inputted to and captured by the computer 85.3. The computer may be programmed to store a continuous stream of data similar to the embodiment described for
Vehicle 10 has transducers 80.4 hydraulically connected to its arm cylinders 70, a pair of transducers hydraulically connected to its fork cylinders 52, as shown by transducer 91, and may also have a pair of transducer (not shown) hydraulically connected to hydraulic cylinders (not shown) for its garbage door (not shown). If vehicle 10 were a fork lift instead of a garbage truck, similarly there may be transducers and hydraulic cylinders for lifting up and down, transducers and hydraulic cylinders for tilting forks, and transducers and hydraulic cylinders for moving the forks side to side.
In order to calibrate accurately, the operator needs only use one of the above mentioned pairs of cylinders and transducers. The other two pairs of cylinders should not have their valves open when the operator is taking readings in this example.
To calibrate system 78.4, lifting arms 28 in an unloaded state are moved to a static, set position 96, which in this example is a position where container 46 is above and approximately parallel with the ground 26 as seen in
Next, a load of known weight 98, as shown in
The computer determines if only one pair of actuators and transducers is being used at box 117 and is active. If yes, the computer determines and stores a pattern relating actuator pressure to time at box 118 based on signals of the transducer at a series of points along the load cycle for the load of known weight and the rate of flow of hydraulic fluid. If no, the computer signals to the operator to repeat the step shown in box 116.
The pressure in the cylinder 70, seen in
Steps 108 to 119 are repeated for a plurality of other loads of known weights and a plurality of patterns relating pressure to time during the load cycle are generated by the computer, as shown by box 120. These patterns are stored in the memory of the computer. This may be referred to as a means for generating and storing a plurality of set patterns for a plurality of loads of known weight moving through the load cycle for a plurality of rates of flows of hydraulic fluid passing into and out of the actuator
The patterns are also consistent when lowering the lifting arms. This is shown by troughs 131 and 133 for pattern 125.
Put another way, patterns recorded and shown in
An indication of the speed with which the lifting arms are moved is determined by the computer based on the distance between adjacent lines of the pattern generated from lifting and lowering the load, respectively. The space between lines represents the number of readings over time, which provides a reliable time reference. In this example the x axis represent reading numbers and there are approximately 10 readings per second. Lines 137 and 138, corresponding to lifting and lowering for pattern 123 for a weight of 559 pounds, are spaced-apart by an average distance D1. Peaks 127 and 129 represent times when the lifting. With the rate of flow of hydraulic fluid into the cylinder kept constant, the pressure readings will be consistent at the peaks 127 and 129. The same holds for the rate of flow of hydraulic fluid out of the cylinder.
Lines 141 and 143, corresponding to lifting and lowering for pattern 125 for the same weight of 559 pounds, are spaced-apart apart by an average distance D2 which is less than D1. The closer these lines are, the faster the lifting arms are moving. If one combines a load having a known weight with a calculated rate of flow of hydraulic fluid into the cylinder, dynamic repeatable patterns result which the computer determines and stores in its memory for comparing with the pattern of a payload of unknown weight.
The computer 85.4 next correlates therefrom at 122 a relationship between the plurality of signals and weight on the lifting arm. In this example, this is done by using the plurality of signals for the plurality of loads of known weights where the lifting arms are in the set position and determines a relationship between weight and pressure thereby. To zero the relationship, computer 85.4 may determine a value of the combination of the known weight 98 and the weight of the lifting arm and container in terms of pressure. The computer next subtracts the value of the combination of the known weight and the weight of the lifting arm to determine a value of the known weight 98 in terms of pressure. With a sufficient number of known weights, the computer may determine a correlation between a given pressure reading of the transducer 80.4 and a given weight thereby. This may be referred to as a means for correlating actuator pressure within the actuator at a set position of the lifting arm with weight for generating a calculated weight of a payload
As seen in
Thus, system 78.4 as herein described determines the calculated weight of the payload when the vehicle 10 and payload 100, seen in
Referring back to
The computer next determines the rate of flow of hydraulic fluid passing into and out of the actuators of the lifting arms when moved during the movement of the payload through the load cycle based on the distance between adjacent measurement lines of the pattern corresponding to where the payload was lifted and lowered, respectively. The rate of flow of hydraulic fluid into and out of the actuators relates to the speed with which the actuators and lifting arms move. This is shown as box 134. This is also shown by lines 137 and 138 for pattern 123 and lines 141 and 143 for pattern 125 in
Referring back to
If so, the computer signals at 138 that the system 78.4 must be recalibrated, by going to step 102 in
If the deviation is acceptable at 140, the computer stores and saves the calculated weight of the payload. The system then repeats the above steps beginning with step 124 for the next payload. This may be referred to as a means for comparing the payload pattern with a set pattern relating actuator pressure to time corresponding to the calculated weight of the payload and rate of flow of hydraulic fluid and recalibrating the correlation between actuator pressure and weight if the deviation between the patterns is greater than a certain amount. Alternatively, it may be referred to as a means for generating a pattern relating pressure to time for the payload when payload moves through a load cycle and verifying the calculated weight with one of the set patterns corresponding to both the calculated weight of the payload and the rate of flow of hydraulic fluid with which the payload was moved through the load cycle.
Thus, the system 78.4 as herein described uses the information derived from actual payload patterns and compares them to stored patterns to determine if the calculated weight of the payload is accurate. In this manner, the weight of a plurality of payloads may be calculated and stored in the computer in an accurate and reliable manner.
According to one embodiment, the deviation between the patterns is equal to or less than 5% for safety applications where the operator wants to ensure that his load-lifting vehicle is not overloaded. Thus, in this example if a set number of payload curve points are accurate within 5% compared to the series of curve points of the known load for the same flow rates of hydraulic fluid while lifting and lowering the arms, the calculated weight of the payload is accepted and stored in the computer. For trade applications where the amount of load transported needs to be determined and tracked with greater accuracy, the deviation between the patterns is equal to or less than 0.5% according to one example. The system as herein described may have 0.1% weight measurement accuracy for fork lifts. The system as herein described may have 0.25% weight measurement accuracy or better for garbage trucks.
In one variation, the system as herein described may compare a portion of the beginning of the payload pattern towards the beginning of the load cycle with a portion of the beginning of the set pattern. This is because, typically, an operator will begin lifting his load at a slow, more constant speed manner. This may be referred to as means for comparing a portion of the beginning of the payload pattern towards the beginning of the load cycle with a portion of the beginning of the set pattern.
Advantageously, the system 78.4 as herein described enables an operator to verify weight readings while the vehicle is in motion. Thus, the system as herein described may calculate the weight of a payload while the vehicle is idle and verify the calculated weight while it is moving and performing tasks. This may save time and result in a more accurate system. Alternatively, the system may be readily adapted to calculate the weight of a payload while the vehicle is moving using the patterns and verify the calculated weight while idle.
The system 78.4 as herein described only stores data when only one actuator/pair-of-corresponding-transducers is being used as shown in box 117 of
According to a further variation, the patterns referred to above may be used to self-calibrate the system. For example, if a weight of 800 pounds results in a pressure reading of 900 psi with a calibrated base of 0 pounds equaling 0 psi, then the patterns as herein described may indicate a pressure reading of 900 psi, for example. If the base psi pressure drifts to 5 psi from 0 psi, then the resulting pressure reading of 900 psi would increase to 905 psi. The patterns remain the same for a given weight and rate of flow of hydraulic fluid with a 5 psi increase overall and would simply be offset by 5 psi. Advantageously, the patterns so stored enable the computer 85.4 to identify the patterns so offset and to self-adjust the calibration of the system accordingly. This may be referred to a means for using the patterns to identify and determine drift in pressure readings and for self-adjusting for said drift in pressure readings thereby.
System 78.4 may be used as part of a method of tracking payloads as shown in
If the transporting vehicle is not fully loaded at 146, loading continues at 144. If the transporting vehicle is fully loaded, the computer determines and stores the total weight of payloads transported by the load-lifting vehicle onto a load-transporting vehicle by way of the load monitoring system 78.4 as described above and as generally shown by box 148. This information is transmitted 147 to and kept at the distribution center at 142. The information is also stored in the load-transporting vehicle for the truck driver, for example, to observe the information in real time.
The distribution center in response sends a certification signal 149 to the transporting vehicle, as shown by box 150. If the certification signal is not received, the transporting vehicle again sends its transmitting signal to the center. If the certification signal is received, the transporting vehicle next drives to a central weighing facility, in this example a government or municipal weighting facility and transmits a certified weight signal in response to the weighing facility, as generally shown by box 152. The certified weight signal correlates with the certification signal of box 150, indicates that the load-transporting vehicle is certified and indicates the total weight of the payloads carried by the transporting vehicle.
The weighing facility determines at 154 if the certified weight signal is indeed certified. If yes, the facility stores the payload weight information and signals to the load-transporting vehicle to bypass any line-up and weigh scale and proceed directly to its end destination. The weighing facility thereby allows transporting vehicles coming from certified distribution centers to bypass weigh scales and enables the transporting vehicle to move its goods in a time efficient manner. This is shown generally by box 156.
If the weighing facility determines that the signal is not certified or if it detects an error signal of some kind, the facility transmits a stop signal to the transporting vehicle requiring that the transporting vehicle be weighed on the scales. At 158, if the transporting vehicle is not certified by the distribution center, if the transporting vehicle comes from a non-certified distribution center, or if there is some other error, the weighing facility may stop the transporting vehicle from passing by sending out the stop signal.
The vehicle can be tracked by GPS. This may be a factor in determining whether the driver is to be authorized to bypass the scale. This is because if the driver has taken too long to get the facility, the driver may have gone to another stop and changed his load. Alternatively, the GPS route data may indicate that the driver stopped at another location, which may be another factor for the facility to stop the vehicle.
Because of the accuracy provided by system 78.4, the method of tracking may further include a charging-by-weight feature, by charging the distribution center or other user of the system at a fixed rate of value per unit of weight of payload for the use of the system 78.4. One could charge the user of the system at a rate of 1/10th or 1/100th of a cent per pound of payload moved, for example. In this manner, the method of tracking may provide the user of the system 78.4 with the advantage of lower up-front costs. This charging-by-weight feature may be instead of or in addition to selling and/or licensing the systems 78.4 as separate units.
In a sixth embodiment or variation of the invention and as shown in
All of this information may be transmitted at 164 in real time to a waste load tracking control center through, for example, wireless or cellular transmission. The steps shown in boxes 160 to 164 may then be repeated for each container along the vehicle's route, as shown by box 166. The computer may determine at 168 a preferred travel route for the vehicle based on the GPS tracking information, which is particularly advantageous for a new or temporary driver not familiar with the optimal approach routes and paths for the waste disposal vehicle to approach containers in a given neighbourhood. By pressing a button, the computer with its data thus stored may readily pull up on its display a tailored map for preferred approach routes.
This may be particularly useful, for example, to inhibit a driver from approaching an alley in the wrong direction such that the forks of the waste disposal vehicle cannot pick up a garbage bin. If a waste disposal vehicle has, for example, one hundred garbage bins to pick up in a given route, entering the alley the wrong way may force the driver to turn his vehicle around and this may result in a loss of 10 or 15 minutes, for example.
The computer as herein described for each of the load weighing systems may comprise a CPU (computer processing unit), memory, analog to digital converters, USB ports, a memory card reader, a serial port, a modem, a plurality of connector ports for connecting to a variety of devices and an expansion slot. The following devices may connect to the computer: two-way radios to send and receive data, a cellular phone, a GPS receiver to collect location data, a WIFI system to send and receive data, and a radio-frequency identification (RFID) system to collect asset data and to send and receive data, and input-output (I/O) devices to connect to vehicle computers and record speed, hours, mileage and pressure readings.
The data collected by the systems as described herein may be used for a variety of operational, administrative and analysis purposes. The systems thus may represent an all-in-one solution and system for load-lifting vehicles that incorporates weight load tracking, data management, paper reduction, data automation, real time data analysis, targeted billing capabilities, mapping functions and a general communication system. The system as herein described may thus replace other, more incomplete solutions and provide a single platform with which companies can expand.
Many further advantages result from the structure of the present invention. The load measuring systems as herein described may adapt to any dynamic environment, are self-calibrating and may be more accurate and reliable compared to existing systems. The systems as herein described provide the advantage of being readily operational with a large variety of load-lifting vehicles, including a large variety of waste disposal vehicles of different sizes, cabs, frames, arms and fork configurations and associated different vehicle loads and dynamics. The load measuring systems as herein described provide reliable measurements of the weight of a waste load regardless of the above set out variations in mechanical characteristics of the vehicles, as well as regardless of further potentially complicating variables such as differing inclines or declines in ground surfaces to which the vehicle may be subjected at any given time and variations in the positioning of the waste containers on the forks. This accumulated, more reliable and accurate information may provide opportunities for increased productivity and profits.
The computer and software aspects of the system as herein described provide the advantage of keeping track of fleet assets in real time and the ability to export collected information to accounting systems.
The load measuring systems as herein described may be used in association with a large variety of vehicles in addition to waste loading vehicles. Other load-lifting vehicles with which the load measuring system as herein described may be used include: excavators, log loaders, fork lifts, shipping container lifts, rock quarry vehicles and any other vehicle or machine that lifts loads via hydraulics. The systems as herein described may be used for hydraulic cranes, which have multiple hydraulic actuators.
It will be appreciated that still further variations are possible within the scope of the invention described herein. For example, the computer as herein described may have a plurality of analog to digital converters for converting outputs from multiple transducers into digital readings in this example. Thus, the system has the capacity for receiving multiple output signals from an unlimited number of transducers or load cells. In one preferred example, the computer may have nine sensor inputs, though not limited to such. The computer thus also has the ability to replace the computers of competitors and also integrate with existing load measuring systems.
The load measuring systems as herein described may include a pair of hydraulic transducers. In other embodiments only one hydraulic transducer may be used, particularly if awareness and measurement of load imbalances between arms is not important. The specific configuration and number of the load cells for system 78.2 shown in
It will be understood by someone skilled in the art that many of the details provided above are by way of example only and are not intended to limit the scope of the invention which is to be determined with reference to the following claims.
This application claims the benefit of provisional application No. 61/485,866 filed in the United States Patent and Trademark Office on May 13, 2011, the disclosure of which is incorporated herein by reference and priority to which is claimed.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/CA12/50313 | 5/11/2012 | WO | 00 | 9/12/2013 |
Number | Date | Country | |
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61485866 | May 2011 | US |