WO2010041053A2 - Dispositif de surveillance d'entretien - Google Patents

Dispositif de surveillance d'entretien Download PDF

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Publication number
WO2010041053A2
WO2010041053A2 PCT/GB2009/051318 GB2009051318W WO2010041053A2 WO 2010041053 A2 WO2010041053 A2 WO 2010041053A2 GB 2009051318 W GB2009051318 W GB 2009051318W WO 2010041053 A2 WO2010041053 A2 WO 2010041053A2
Authority
WO
WIPO (PCT)
Prior art keywords
tool
vibration
threshold
servicing
indicative
Prior art date
Application number
PCT/GB2009/051318
Other languages
English (en)
Other versions
WO2010041053A3 (fr
Inventor
Andrew Micklethwaite
Sara Jayne Hildreth
Michael James Jones
Beatrix Joy Dunlop Jones
Original Assignee
Beckwith Ip Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB0818327A external-priority patent/GB0818327D0/en
Priority claimed from GB0908350A external-priority patent/GB0908350D0/en
Application filed by Beckwith Ip Limited filed Critical Beckwith Ip Limited
Publication of WO2010041053A2 publication Critical patent/WO2010041053A2/fr
Publication of WO2010041053A3 publication Critical patent/WO2010041053A3/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H1/00—Measuring characteristics of vibrations in solids by using direct conduction to the detector
    • G01H1/003—Measuring characteristics of vibrations in solids by using direct conduction to the detector of rotating machines
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H3/00—Measuring characteristics of vibrations by using a detector in a fluid
    • G01H3/10—Amplitude; Power
    • G01H3/14—Measuring mean amplitude; Measuring mean power; Measuring time integral of power

Definitions

  • the present invention relates to a servicing monitor arranged to monitor use of a machine or a tool or another piece of equipment and to provide an operator of the machine or tool an indication when servicing is required, hi particular, the present invention relates to a servicing monitor arranged to monitor the use of a machine or a tool by sensing vibration of the machine or tool indicative of normal use.
  • tools Engineering machinery and power tools, including hand held power tools, (hereinafter “tools”) require periodic servicing or maintenance in order to ensure that they function correctly. Furthermore, the term “tool” should be interpreted broadly as including any item which requires periodic servicing to ensure correct functioning, such as bearings within a machine. Such tools are commonly used in the engineering, construction, maintenance, woodworking, landscaping and forestry industries and other related industries. The tools may for instance be driven by electricity, pneumatics, hydraulics, batteries or an engine. Such tools typically comprise a number of moving parts such as motors, which vibrate when in use potentially causing damage to the tool.
  • Too infrequent servicing can result in damage to the tool, reduced performance or increased vibration levels which can be extremely costly to repair, or cause the tool to be scrapped because it is not economic to repair, hi some cases users decide not to repair tools and scrap them when they fail at considerable cost. Too infrequent servicing may also increase the cost of use, increase the consumption of consumables, reduce the torque repeatability to the tool and have potential consequences for operator health and safety. Consequently, it is known for tool manufacturers to specify standard servicing intervals, for instance once every three months. Such servicing intervals are based upon an estimation of the likely usage of the tool. Such an estimate must necessarily be conservative in order to ensure that the next service is performed before damage is likely to have occurred. Consequently, in most cases, servicing is performed before it is strictly required, which increases the cost of servicing to the user.
  • a sensor is provided to sense the supply of power from a source to a tool and monitoring means responsive to the sensor record the time elapsed during the supply of power.
  • Torque "failure” (defined as a fastening for which a lower or higher torque value has been applied) is one of the most common reasons for product recall, in particular where such torque failure has the potential to cause component failure within the final product. In addition to the safety implications of torque failure the monetary consequences of a product recall can be severe.
  • Common methods of torque setting fasteners within a production environment include impact wrenches, impulse wrenches and impulse screwdrivers. Such tools are generally pneumatically powered but electric, hydraulic and petrol/diesel engine variants also exist.
  • Impulse type products offer high levels of preset torque repeatability, so long as the tool manufacturer's preventative maintenance recommendations are followed correctly. These preventative maintenance recommendations are based on a number of fastening cycles (that is, trigger depressions) between tool servicing, rather than the elapsed tool usage.
  • the number of fastenings per component may be used to manually calculate impulse tool maintenance cycles. While this is theoretically possible, in practice it is prone to error as trigger depressions can inadvertently take place when operators are awaiting next component.
  • a further option is to periodically check the torque applied by the impulse tool using a test rig whereby sensors are applied to the tool and operational characteristics downloaded to a computer for review. While this allows for an accurate determination of the performance of the tool, this approach can be prohibitively expensive as such test rigs may cost more than the tool itself.
  • Vibration sensors are well known for monitoring the exposure of tool operators to vibration.
  • Current health and safety considerations require that all tool operators who come into contact with tool vibration as part of their daily duties should monitor the duration of that exposure and limit that exposure on a daily basis.
  • a responsibility lies with the employer to facilitate and perhaps oversee that exposure duration management.
  • HAVS is a function of both the magnitude of the vibration and the duration of the exposure to that vibration.
  • a multi-axis accelerometer may be used such as a Hand- Arm Vibration Meter Type 2239B manufactured by Bruel and Kjaer of Denmark.
  • the meter is attached to the tool at the or each precise location where a user can be expected normally to place each of his or her hands to use the tool or machine.
  • the vibration measured in m.s "2 , must then be measured over three runs each of two minutes duration and the highest vibration output per run is averaged over the three runs. If the different hand locations at which the vibration is tested give different results, then the higher or highest values is recorded.
  • GB-2411472 (South West Highways Ltd of the United Kingdom) discloses a vibration monitor to be worn on the wrist of a tool operator.
  • the monitor of GB-2411472 records time, magnitude and frequency information for sensed vibration over a predetermined period of time (typically over a single shift).
  • the vibration magnitude and frequency information is stored within the monitor for later retrieval when the monitor is coupled to a computer.
  • This information is then used to generate a spectrograph on the computer, which in turn is used to calculate the exposure of the tool operator to vibration and determine if that exposure exceeds safe limits.
  • the vibration data may be transmitted wirelessly in real time to the computer to monitor the current exposure of the tool operator. It is noted that the spectrograph may be further interpreted to analyse the condition of the tool.
  • the vibration monitor of GB-2299169 (British Gas PIc of the United Kingdom) is also intended to be worn on the wrist of a tool operator.
  • a vibration-activated transmitter coupled to each tool sends a radio signal to the monitor whenever that tool is in use.
  • the radio signal identifies the tool to the vibration monitor.
  • the vibration monitor on the operator's wrist has its own vibration sensor and is arranged to record the cumulative period for which the vibration exceeds a threshold indicating that the user is using the tool.
  • the vibration monitor is pre-programmed with information regarding the actual emitted vibration from each tool and so is able to calculate the operator's exposure, even though the vibration sensed at the wrist may differ from the true emission from this data and the duration data.
  • the vibration monitor is able to warn when safe exposure limits are reached.
  • WO-2007/072068 discloses a vibration monitor that is attached to a tool rather than to the wrist of a user.
  • the monitor is in two parts: a mount affixed to the tool and a personal monitoring component.
  • the personal monitoring component is detachable from the mount and can be carried by an operator from one tool to another for coupling to the mounts for each tool to be used by that operator.
  • An accelerometer contained in either the mount or the personal monitoring detects vibration of the tool. The cumulative vibration exposure of the operator is calculated and communicated to the operator or recorded for later analysis when the data is downloaded to a computer.
  • the personal monitoring component when attached to the machine or tool has three highly visible coloured LED display lights. Green indicates that it is safe to continue to use the tool. Amber indicates that the user must be cautious because the period of exposure to vibration for that particular shift is drawing to an end. Red indicates that the user ought to discontinue using the machine or tool because his/her daily exposure limit has been reached. Additionally, a three digit display may be provided to display the remaining exposure for that operator before they must stop using the tool.
  • the vibration monitor of WO-2007/072068 is also capable of detecting if the measured vibration level exceeds a predetermined threshold in excess of the typical vibration experienced during normal operation of the tool. If the vibration exceeds that threshold then the operator is alerted. If the vibration exceeds the threshold then this may indicate a fault within the tool or the need to have the tool serviced.
  • a servicing monitor which is couplable to a tool for monitoring use of the tool, comprising: a vibration sensor arranged to detect vibration of the tool and to provide a vibration signal indicative of the magnitude of the tool vibration; and a processor configured to receive the vibration signal and to determine whether the vibration signal exceeds a stored first threshold indicative of the tool being in use; wherein the processor is arranged to provide a first output signal to an operator of the tool if the cumulative period of time during which the vibration signal is above the first threshold exceeds a predetermined service interval; wherein the processor is further arranged to store at least a portion of vibration signal data received from the vibration sensor during a predetermined first period of time, to calculate a value indicative of the magnitude of normal tool vibration over the first period of time, and to determine a second threshold indicative of a potential tool malfunction from the normal tool vibration magnitude; and wherein the processor is arranged to provide a second output signal to an operator of the tool if the vibration signal exceeds the second threshold.
  • An advantage of the first aspect of the present invention is that calculation of the second threshold and monitoring of the second threshold allows excessive vibration which is either indicative of damage to the tool or liable to cause damage to the tool may be detected.
  • the second threshold is calculated dynamically based upon measurement of the actual vibration emitted by a tool the servicing monitor can be used in connection with any tool without requiring pre-configuration to set a second threshold indicative of potential damage.
  • the value indicative of the magnitude of normal tool vibration may comprise an average of the vibration signal data stored during the first period of time.
  • the processor may be arranged to determine the second threshold as at least 10% above the value indicative of the magnitude of normal tool vibration.
  • the servicing monitor may further comprise input means arranged to receive an input signal from an operator of the tool and wherein in response to receiving an input signal the processor is arranged to store at least a portion of vibration signal data received from the vibration sensor during a further predetermined period of time, to calculate an update value indicative of the magnitude of normal tool vibration over the further period of time, and to determine an updated second threshold.
  • a servicing monitor which is couplable to a tool for monitoring use of the tool, comprising: a vibration sensor arranged to detect vibration of the tool and to provide a vibration signal indicative of the magnitude of the tool vibration; and a processor configured to receive the vibration signal and to determine whether the vibration signal exceeds a stored first threshold indicative of the tool being in use; wherein the processor is arranged to provide a first output signal to an operator of the tool if the cumulative period of time during which the vibration signal is above the first threshold exceeds a predetermined service interval; and wherein the servicing monitor further comprises a display arranged to display to the operator of the tool a value indicative of the difference between the cumulative period of time and the predetermined service interval.
  • the display indicates the tool usage time to the next required service allows tool operators to better plan for and meet their servicing requirements, which results in a reduction in the period of time during which the tool is unavailable and a reduction in servicing costs due to being able to more reliably provide servicing resources.
  • the display may be arranged to display the difference value in hours. When the value indicative of the difference between the cumulative period of time and the predetermined service interval is equal to zero the display may be further arranged to flash.
  • a servicing monitor which is couplable to a tool for monitoring use of the tool, comprising: a vibration sensor arranged to detect vibration of the tool and to provide a vibration signal indicative of the magnitude of the tool vibration; and a processor configured to receive the vibration signal and to determine whether the vibration signal exceeds a stored first threshold indicative of the tool being in use; wherein the processor is arranged to provide a first output signal to an operator of the tool if the cumulative period of time during which the vibration signal is above the first threshold exceeds a service interval; and wherein the servicing monitor further comprises input means arranged to receive an input signal from an operator of the tool and in response to receiving an input signal the processor is further arranged to update the service interval.
  • the servicing interval may be varied by the operator a single type of servicing monitor can be used to monitoring the servicing needs of a wide range of tools.
  • the input means may comprise a button, and the processor may be arranged to store a predetermined value for the service interval and to vary the service interval in response to an input signal received from the button.
  • the processor may be arranged to sample the received vibration signal at predetermined intervals and to update a stored value indicative of the cumulative period of time during which the vibration signal is above the first threshold by an amount indicative of the time between successive samples if the sampled vibration signal is above the first threshold.
  • the vibration sensor may be arranged to detect vibration of the tool along a single axis of motion.
  • the vibration sensor may be arranged to detect vibration of the tool along at least two orthogonal axes of motion and to provide at least two corresponding vibration signals, wherein the processor is arranged to select the largest of the at least two vibration signals for comparison with the first threshold.
  • the servicing monitor may further comprises a mount for mounting the servicing monitor on an external surface of a tool.
  • a method of monitoring use of the tool comprising: detecting vibration of the tool; generating a vibration signal indicative of the magnitude of the tool vibration; determining whether the vibration signal exceeds a stored first threshold indicative of the tool being in use; providing a first output signal to an operator of the tool if the cumulative period of time during which the vibration signal is above the first threshold exceeds a predetermined service interval; storing at least a portion of vibration signal data received from the vibration sensor during a predetermined first period of time; calculating a value indicative of the magnitude of normal tool vibration over the first period of time; determining a second threshold indicative of a potential malfunction of the tool from the normal tool vibration magnitude; and providing a second output signal to an operator of the tool if the vibration signal exceeds the second threshold.
  • the method may further comprise displaying to the operator of the tool a value indicative of the difference between the cumulative period of time and the predetermined service interval.
  • the method may further comprise receiving an input signal and updating the predetermined service interval.
  • a monitor may be coupled to a tool and arranged to record the cumulative duration of time for which vibration exceeds a first threshold.
  • a tool serial number may be pre-programmed into the monitor.
  • the cumulative duration data may late be downloaded to a computer and the maintenance cycle for the tool identified by the serial number may be illustrated on screen. The number of hours remaining until the next due service may be determined.
  • the monitor may comprise an integral LED arranged to be illuminated when the tool requires servicing. Data relating to previous usage of the tool may be programmed into the monitor at the start of a work shift and updated to reflect new usage of the tool during that shift. Either the total duration of time of use of the tool may be monitored or the time remaining until servicing is required may be monitored.
  • a servicing monitor which is couplable to a tool for monitoring use of the tool, comprising: a vibration sensor arranged to detect vibration of the tool and to provide a vibration signal indicative of the magnitude of the tool vibration; and a processor configured to receive the vibration signal and to determine whether the vibration signal exceeds a stored first threshold indicative of the tool generating an impulse output; wherein the processor is arranged increment an impulse count each time the vibration exceeds the first threshold and to provide a first output signal to an operator of the tool if the count exceeds a predetermined value.
  • An advantage of the third aspect of the present invention is that it provides an easy to install, small, accurate and affordable monitor for determining the use of an impulse tool that is arranged to alert and operator when the tool is due for maintenance.
  • the processor is arranged to not further increment the impulse count until the vibration signal reduces to under the first threshold.
  • the servicing monitor may further comprise a display arranged to display to the operator of the tool the current impulse count.
  • a method of monitoring use of the tool comprising: detecting vibration of the tool; generating a vibration signal indicative of the magnitude of the tool vibration; determining whether the vibration signal exceeds a stored first threshold indicative of the tool generating an impulse output; incrementing an impulse count each time the vibration exceeds the first threshold; providing a first output signal to an operator of the tool if the count exceeds a predetermined value.
  • Figures IA, IB and 1C illustrates respective top, side and bottom views of a servicing monitor in accordance with an embodiment of the present invention
  • Figure 2 illustrates a systems diagram showing the major components of the servicing monitor of figures IA, IB and 1C;
  • Figure 3 illustrates a flow chart illustrating the process of programming the servicing monitor of figures IA, IB and 1C.
  • the servicing monitor comprises a plastic shell 2 which contains and protects the other components.
  • the shell 2 may typically be approximately 50mm long, 8mm wide and 4mm in height.
  • the shell 2 is sonic welded to encapsulate the system and provide the internal components with protection against the ambient environment (which in the case of factories and construction sites may be hazardous for electronic components). It will be appreciated that in other embodiments the size and construction of shell 2 may vary.
  • a display screen 4 which comprises a three digit LCD counter, and a button 6 (which is recessed within the shell 2 to prevent it being pressed inadvertently and so is not clearly visible in figures IA, IB and 1C).
  • the display may for instance be a custom glass LCD and red backlight such as a PL5001A LCD display and PL2015 backlight commercially available from Pilot Technology Co. Ltd.
  • the servicing monitor is powered by an internal battery 8. Any commercially available battery, such as a CR2032 battery with a minimum capacity of 230mAhr may be used, though it will be appreciated that the required capacity is dependent upon the expected time between servicing for a given tool.
  • a commercially available battery such as a CR2032 battery with a minimum capacity of 230mAhr may be used, though it will be appreciated that the required capacity is dependent upon the expected time between servicing for a given tool.
  • the servicing monitor is first supplied, to prevent it being activated before it is required the battery contacts within the shell 2 are separated by a plastic film 10 which extends from the shell and has a pull tab.
  • the servicing monitor is required for use the plastic film 10 is removed connecting the battery 8 to the processor 12.
  • the action of the plastic film 10 is represented schematically in figure 2 as a switch 14 between the battery 4 and the processor 10.
  • the servicing monitor is arranged to be coupled to a tool by an adhesive or an adhesive pad (not illustrated) on the bottom of the monitor.
  • the vibration monitor may be a single use application such that it is not necessary to be able to remove the adhesive pad from the tool without damaging the adhesive or the monitor.
  • the adhesive pad incorporates a layer of foam or a similar compressible material between the monitor and the adhesive such that the monitor may be affixed to curved tool surfaces.
  • a suitable adhesive is chosen that is capable of bonding to composite, plastic and metal surfaces for a minimum period of three months (or longer if the servicing interval is not expected to expire within that period).
  • the adhesive should be capable of securing the monitor throughout the expected temperature range within which the tool may be used (such as in a factory or on a construction site), for instance -20°C to +35 0 C.
  • the servicing monitor may be coupled to a machine using cable ties.
  • the side view of figure IB shows first and second holes 22 arranged to receive cable ties which pass through the servicing monitor and are secured to part of the tool.
  • the vibration sensor 16 is arranged to detect vibration of the tool and pass a vibration signal to the processor 12.
  • the vibration sensor 16 may be a single or a multiple axis accelerometer, or any other sensor capable of detecting vibration.
  • the vibration sensor 16 is capable of measuring the magnitude of the vibration and providing an output signal indicative of the magnitude of the detected vibration to the processor 12.
  • the processor 12 and the vibration sensor 16 may be a single unit.
  • the processor 12 is arranged to detect whether the output vibration signal from the vibration sensor is greater than a first threshold. The first threshold is indicative of a magnitude of tool vibration indicating that the tool is in normal use.
  • the servicing monitor may be sensitive to a wide range of vibration magnitudes ranging from approximately lmm.s "2 for monitoring vibration of bearings to lOm.s "2 for monitoring vibration of large machine tools.
  • the processor is arranged to measure the cumulative period of time for which the tool has experience vibration above the first threshold (that is, the cumulative amount of time the tool has been used). This can then be compared to a stored value for the servicing interval (that is, the total duration of tool usage between servicing) to identify when the servicing interval has been reached.
  • the processor may decrement a counter indicative of the time remaining to the next required tool service by the period of time during which the vibration signal is received.
  • the processor 12 may be implemented using any appropriate programmable chip able to receive a vibration signal, compare the vibration signal against a stored threshold, update a stored value indicative of the cumulative period of use of the tool (that is, when the vibration signal is above the threshold) and compare the stored value against a stored service interval.
  • One such processor is a micro-controller with a 10-bit analogue to digital converter and LCD output drive, for instance the MC9RSLA808 commercially available from Freescale.
  • the received analogue vibration signal is converted to a digital signal by the processor.
  • each axis of the accelerometer 16 (x, y, z) is connected to the micro-controller through a ceramic DC blocker capacitor (lOuF).
  • the output of the capacitor is balanced to the mid-point of the battery supply with a pair of resistors.
  • the balanced outputs representing the X, Y, Z axes are connected to the micro-controller's analogue to digital converter individually to provide three separate vibration signals for processing.
  • the first threshold indicative of a vibration magnitude representing normal tool usage may be fixed for the servicing monitor.
  • the first threshold may for instance be fixed at 0.5m.s "2 which is considered to be less than the normal operating vibration magnitude of most machines and tools, but greater than the vibration likely to be encountered during storage and transit.
  • the first threshold may differ.
  • a duration value indicative of the cumulative period of use of the tool since the monitor was activated is updated.
  • the current period of tool use may be subtracted from the stored service interval. The difference is zero then an output signal is triggered indicating to the user that the tool requires servicing.
  • the display preferably displays a value equal to the difference between the service interval and the tool use duration value, that is as the tool is used the display counts down the number of hours of tool use remaining until the tool requires servicing. It will be appreciated that in alternative embodiments of the invention the counter may count upwards, that is the displayed value is equal to the cumulative number of hours of tool use. Calculation of the time to the next required tool service will be described in greater detail below.
  • Figures IA, IB and 1C further illustrate a bar code or serial number 18 and a product logo area 20.
  • the bar code or serial number 18 may be used for stock management purposes, which may be particularly useful for organisations responsible for large numbers of tools and servicing monitors.
  • the bar code or serial number 18 also allows for manufacturing traceability and for users to keep a record of when tools are serviced and issued, that is allowing users to use the servicing monitor as an administrative tracking device.
  • Display 4 is arranged to display a three digit value equal to the period of tool use (in hours) remaining until the next required tool service.
  • the service interval may be set upon initialisation of the monitor between 50 hours and 950 hours, as will be described in greater detail below. By displaying the remaining time the tool operator is better able to plan for the servicing requirements of the tool.
  • there may be no display and an output signal, for instance a flashing LED may be triggered only when the tool service is due.
  • the shell 2 may be translucent to further enhance the flashing LED (which may, for instance, be required to flash once per second for at least 4 hours).
  • the service interval may be not be variable, for instance it may be set permanently to 200 hours.
  • the processor 12 of a servicing monitor in accordance with certain embodiments of the invention may be arranged to calculate a second vibration threshold based upon measurement of the average or maximum vibration magnitude during a first period of operation of the monitor. If that second threshold is exceeded then a further output signal is provided to the tool operator, for instance the background of the display may flash red, indicating to the operator that the tool may require immediate servicing due to a malfunction. If the vibration signal is below the first threshold, then the monitor determines that the tool is not in use (so as to prevent vibration during storage and transit of the tool being interpreted as use of the tool). In between the first and second threshold the processor determines that the tool is in normal use, and so updates the tool usage duration value accordingly. A vibration signal above the second threshold can be used to identify a tool which is faulty and in need of immediate servicing.
  • an output signal may be provided to the user to indicate that immediate servicing is required, and the servicing monitor may cease operation
  • the servicing monitor may provide an output signal to the operator indicating that servicing may be required, however the vibration signal measurement and updating of the cumulative period for which the vibration signal has exceeded the first threshold may continue.
  • the alternative embodiment of the invention envisages the situation in which after the second threshold has been determined the operator of the tool uses the tool in a different way, still within the operational bounds of the tool, which results in a significantly higher vibration signal being measured.
  • the tool vibration may be low and the second threshold may be set to a low level. If later the tool is used to cut metal then the vibration will be significantly higher such that the second threshold is exceeded without this indicating a tool fault. Immediate servicing is unlikely to be required and the operator will not want to have to replace the servicing monitor.
  • the operator may either continue to operate the tool without paying attention to the second threshold being exceeded, or the operator may trigger the generation of a new second threshold reflecting the higher vibration use of the tool. The generation of a new second threshold may be achieved by pressing the button for a further predetermined period of time.
  • the button 6 is used upon initial activation of the device (when the plastic film 10 is removed) to program the service interval, as will be explained in greater detail below in connection with the flow chart of figure 3.
  • the servicing monitor is a stand alone device and does not require connection to another device, for instance a computer, to be programmed or to operate.
  • the servicing monitor is intended to be disposed of upon expiry of the service interval, and replaced with a fresh servicing monitor.
  • step S2 the plastic film is removed from the shell to connect the battery terminals to the processor.
  • the servicing monitor is then ready for use but is initially dormant until activation by depressing the button continuously for 5 seconds is detected at step S4. Once activated the servicing monitor is ready for programming. This is indicated to the user by the LCD display displaying 50 (indicating the default service interval of 50 hours of tool use) and flashing at step S6.
  • step S8 if a single further press of the button is detected then the processes passes to step SlO. If not then the display continues to flash the current set service interval at step S6. If a button press is detected, then at step SlO a check is made whether the current service interval is less than 950 hours. If so, then at step S 12 the service interval is incremented by 50 hours and the new value is displayed in the flashing display at step S6.
  • step S 14 if a double press of the button in rapid succession is detected then the process passes to step S 16 where a check is made whether the current service interval is greater than 50 hours. If so, then at step Sl 8 the service interval is decremented by 50 hours and the new value is displayed in the flashing display at step S6.
  • the three LCD digits continue to flash.
  • the screen may also be backlit red.
  • the user may program the service interval into the servicing monitor.
  • the service interval is set, the display ceases to flash and the set service interval (in hours) is displayed.
  • the servicing monitor is then ready to begin detecting tool vibration and recording the cumulative duration of normal tool usage, as described below.
  • the present invention allows the processor to detect that an excessive vibration signal has been received and immediately alert the operator that the tool may be faulty and requires immediate servicing.
  • This feature may be deactivated by default.
  • the processor determines whether a depression of the button of at least 10 seconds is detected continuously between 15 and 60 seconds after the programming is completed at step S20. If so, the processor proceeds to determine the second threshold at steps S24 to S26. Activation of this feature is acknowledged by the screen flashing and being backlit red. Steps S24 and S26 may be performed in parallel to the monitoring for detection of vibration exceeding the first threshold. If the 10 second button press is not detected at step S22 then steps S24 and S26 are omitted.
  • the processor stores at least a portion of the vibration signal received from the vibration sensor during a predetermined period of time of tool usage. For instance, the magnitude of the vibration signal during the first hour of tool operation may be stored. That is, for a cumulative hour during which the vibration signal exceeds the first threshold the processor records the actual magnitude of the vibration signal. At the end of the accumulated hour the processor calculates an average vibration signal magnitude indicative of normal tool usage at step S26. Alternatively the normal tool usage magnitude may be set to the maximum vibration signal received during the first hour. The processor then calculates a second threshold indicative of damage to or malfunction of the tool from the value indicative of normal tool usage. For instance, the second threshold may be set to at least 10%, and preferably 30% above the average magnitude for that tool.
  • the period of time for calculating the normal tool vibration magnitude may vary depending upon the intended application of the servicing monitor. If the servicing monitor is applied to the tool and activated immediately after the tool was last serviced then it can be safely assumed that the tool is not faulty and so the vibration magnitudes during the first hour will be indicative of normal tool usage.
  • the calculation of the average vibration may simply comprise averaging the first five vibration samples above the first threshold as determined at steps S30 and S32, as described below.
  • the processor enters normal operation, hi order to preserve battery life the processor and the display spend the majority of the time in a low power mode, turning on at a duty cycle of 1:100.
  • the processor powers up and receives the current vibration signal from the vibration sensor.
  • the processor receives a signal on three channels (x, y, z) and passes each in turn to the analogue to digital converter. This periodic process continues indefinitely after the operation is initiated at step S20 until the battery is flat.
  • the outputs from the analogue to digital converter are compared and the largest value retained. This is used to calculate the equivalent acceleration vector using a 512 x 16-bit look up table.
  • the processor determines whether the vector exceeds the first preset threshold (for instance 0.5m.s "2 ). If so then at step S34 the processor increments a tool usage counter, which records the cumulative amount of tool usage in seconds, by a number of seconds equal to the interval between successive vibration signal sampling (on the assumption that in the worst case the tool has been vibrating above the first threshold for the whole of the intervening period). If the second counter reaches 3600 then the counter wraps back to zero and an hour counter (set initially to the programmed service interval) is decremented. The remaining time on the hour counter (number of hours of tool use remaining until servicing is due) is displayed on the LCD display counter. At step S36 a determination is made whether the hour counter has reached zero. If so then the process ends at step S38. AU three digits flash and the display is backlit red providing a clear indication to the operator that the servicing interval has been reached and that the tool should be removed from use and serviced.
  • a tool usage counter which records the cumulative amount of tool usage in seconds, by a number of
  • step S40 a determination is made whether the magnitude of the vibration signal exceeds the second threshold (if this feature has been activated at step S22). If so then the process ends at step S42. Again the LCD display flashes and is backlit red indicating that immediate servicing is required. If not then the process returns to S28 to wait for the next duty cycle. As noted above, in alternative embodiments of the invention operation may instead pass from the output signal of step S42 back to step S22 where the user may optionally trigger the generation of a new, higher second threshold.
  • the display 4 may be disabled when the servicing monitor senses no vibration, in other words when the vibration sensor 16 does not sense vibration consistent with use of the tool (the vibration signal received by the processor is below the first threshold).
  • the servicing monitor may be attached or attachable directly to the body or housing of the tool or machine, preferably in a highly visible location.
  • the mount may be next to the machine motor or vibration plate which receives the maximum amount of vibration, or it may be somewhere on the machine handles. Coupling to the tool may be by adhesive, cable ties or any other suitable technique known to the skilled person.
  • servicing monitors in accordance with embodiments of the present invention have been primarily described above as having a three digit LCD display to indicate the tool usage time remaining before the service interval expires.
  • the servicing monitor may be provided with a single integral LED which may illuminate when the tool is in need of a service, that is, when the service interval has expired.
  • Embodiments of the present invention described above provide an output signal to the tool operator indicating that servicing is required by illuminating a display or LED or other visible or audible output device on the servicing monitor itself. This is particularly useful for tools and machinery that are either portable or are operated by an operator in close proximity to the tool who will be alerted when the servicing interval is exceeded.
  • embodiments of the present invention may be used to monitor servicing requirements for parts of a machine, such as bearings, and so the servicing monitor may be required to be located in a position that is not readily observable to an operator. Therefore, in accordance with certain embodiments of the present invention as an addition or an alternative to providing output information and countdown information directly on the monitor, the same information may be transmitted wirelessly for receipt, processing and display on a remote unit, for instance a factory control panel or a computer. The transmitted information may be only the output signal indicating that servicing is required. Alternately, the cumulative tool duration data, the set servicing interval and / or the raw vibration signal may be transmitted for remote processing.
  • the servicing monitor may optionally include a temperature sensor.
  • the temperature sensor may be used to provided a further indication of tool malfunction or a servicing requirement (if a preset temperature threshold is exceeded).
  • the temperature sensor may be used to monitor the temperature of the servicing monitor itself in order to identify temperature extremes that may cause the monitor to function incorrectly.
  • time stamped temperature data may be continuously stored in order to provide further information that may be transmitted to a remote unit for analysis or retrieved directly from the monitor later on.
  • the servicing monitors described above have generally been described as stand alone devices that do not need to interoperate with other devices for programming or analysis of vibration data. However, it will be readily appreciated by the skilled person that this need not be the case and the servicing monitor may provide communications means, either a wireless or a wired connection, to allow for the first and second thresholds and the servicing interval to be programmed or to allow the extraction of raw or processed vibration data for analysis either in real time or analysis performed upon a stored block of data.
  • Embodiments of the present invention described above relative to servicing monitors arranged to monitor the total duration of tool usage since the tool was last serviced and to alert an operator when the next service is due. This monitoring is based upon detecting whether vibration of the tool exceeds a first threshold and then recording the amount of time for which the vibration exceeds the first threshold.
  • servicing cycles are expressed in terms of the number of impulses generated.
  • the servicing monitor described above and illustrated in figures IA to 2 may be modified to monitor servicing cycles for impulse tools.
  • Such a servicing monitor may be physically identical to the servicing monitors described above and so except where differences are discussed below it may be assumed that the above description is also applicable to the present embodiment of the invention.
  • An impulse tool servicing monitor differs principally from the servicing monitors described above in the way in which the processor 12 is programmed.
  • the vibration sensor 16 continues to provide a vibration signal indicative of the vibration of the tool.
  • the processor 12 is arranged to determine whether the vibration signal exceeds a threshold associated with an impulse. Such a threshold may be generally higher than the thresholds discussed above indicating that a tool is in use.
  • the processor 12 is then arranged to count the number of generated impulses, rather than to record the duration of time for which the vibration is above the threshold. The impulse count may be incremented by one upon the vibration signal rising above the threshold and then not further incremented until the vibration signal has returned below the threshold and then once again exceeds the threshold.
  • the display 4 may be arranged to continuously display the total number of impulses.
  • the processor 12 may be further arranged to compare the cumulative number of impulses with a predetermined number of impulses equivalent to the tool requiring servicing. When the cumulative number of impulses exceeds the predetermined number the display may be arranged to flash red or some other output signal generated.
  • the button 6 may be used to adjust the number of impulses in a service cycle and to reset the count of impulses.

Abstract

L'invention concerne un dispositif de surveillance d'entretien qui peut être raccordé à un outil pour surveiller l'utilisation de l'outil. Le dispositif de surveillance comporte un capteur de vibrations conçu pour détecter les vibrations de l'outil et pour fournir un signal de vibrations indiquant l'amplitude de vibrations de l'outil, ainsi qu'un processeur conçu pour recevoir le signal de vibrations et pour déterminer si le signal de vibrations dépasse un premier seuil mémorisé, ce premier seuil pouvant indiquer que l'outil est en fonctionnement. Le processeur peut être conçu pour fournir un premier signal de sortie à un opérateur utilisant l'outil si la période de temps cumulé durant lequel le signal de vibrations se trouve au-dessus du premier seuil dépasse un intervalle d'entretien prédéfini. Le processeur peut en outre être conçu pour stocker au moins une partie des données du signal de vibrations reçu en provenance du capteur de vibrations pendant un premier laps de temps déterminé, pour calculer une valeur indiquant l'amplitude des vibrations d'outil normales pendant le premier laps de temps, et pour déterminer un deuxième seuil indiquant un dysfonctionnement éventuel d'outil sur la base de l'amplitude normale des vibrations d'outil. Le processeur peut être conçu pour fournir un deuxième signal de sortie à un opérateur utilisant l'outil si le signal de vibrations dépasse le deuxième seuil. En variante, le premier seuil peut indiquer que l'outil génère une impulsion et le processeur peut être conçu pour incrémenter un comptage d'impulsions chaque fois que la vibration dépasse le premier seuil et pour fournir un premier signal de sortie à un opérateur utilisant l'outil si le comptage dépasse une valeur prédéfinie.
PCT/GB2009/051318 2008-10-07 2009-10-06 Dispositif de surveillance d'entretien WO2010041053A2 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB0818327A GB0818327D0 (en) 2008-10-07 2008-10-07 Vibration management device
GB0818327.9 2008-10-07
GB0908350.2 2009-05-15
GB0908350A GB0908350D0 (en) 2009-05-15 2009-05-15 Servicing monitor

Publications (2)

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WO2010041053A2 true WO2010041053A2 (fr) 2010-04-15
WO2010041053A3 WO2010041053A3 (fr) 2011-04-21

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US10821591B2 (en) 2012-11-13 2020-11-03 Milwaukee Electric Tool Corporation High-power cordless, hand-held power tool including a brushless direct current motor
CN113795735A (zh) * 2019-05-31 2021-12-14 Abb瑞士股份有限公司 用于监测旋转装置的方法以及状态监测设备

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WO2007072068A2 (fr) * 2005-12-23 2007-06-28 Reactec Limited Appareil et procede de controle
DE102007010800A1 (de) * 2007-03-02 2008-09-18 Robert Bosch Gmbh Einrichtung und Handwerkzeugmaschine mit einer Einrichtung zur Ermittlung zeitbezogener Vibrationsbelastung

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WO2007072068A2 (fr) * 2005-12-23 2007-06-28 Reactec Limited Appareil et procede de controle
DE102007010800A1 (de) * 2007-03-02 2008-09-18 Robert Bosch Gmbh Einrichtung und Handwerkzeugmaschine mit einer Einrichtung zur Ermittlung zeitbezogener Vibrationsbelastung

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10821591B2 (en) 2012-11-13 2020-11-03 Milwaukee Electric Tool Corporation High-power cordless, hand-held power tool including a brushless direct current motor
US11141851B2 (en) 2012-11-13 2021-10-12 Milwaukee Electric Tool Corporation High-power cordless, hand-held power tool including a brushless direct current motor
US11370099B2 (en) 2012-11-13 2022-06-28 Milwaukee Electric Tool Corporation High-power cordless, hand-held power tool including a brushless direct current motor
US11673248B2 (en) 2012-11-13 2023-06-13 Milwaukee Electric Tool Corporation High-power cordless, hand-held power tool including a brushless direct current motor
CN113795735A (zh) * 2019-05-31 2021-12-14 Abb瑞士股份有限公司 用于监测旋转装置的方法以及状态监测设备

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