Manually operated, pneumatic drilling machines are used for drilling a high proportion of holes during the manufacture of an aircraft in particular the manufacture of wings. Drilling machine design and the manual drilling process has not changed significantly for many years. One of the problems involved with existing tools of that type is the difficulty in keeping track of how long each drill has been in service and whether or not the drill is performing to specification. Also, whilst maintenance records are kept for drills, often they are not particularly accurate and it is not always easy to check whether any particular drill has given rise to a significant number of maintenance problems.

Certain drills are of a semi-automatic type where an operator positions the drill against a surface where a hole is to be made and squeezes the trigger. The drill then starts, feeds the tool or bit into the workpiece automatically to produce the hole and then retracts the tool to complete the drilling cycle. Where a drilling machine is not working to specification, the drilling cycle may well take longer than anticipated but the operator may continue to use the drilling machine for quite some time thereafter before the slow down in cycle time becomes significant.

Problems of the kind set out above have given rise to the present invention which has, as its aim, to produce a system which will enable a machine to be monitored so that problems of the kind set out above can be addressed at an early stage.

According to one aspect of the invention, there is provided a machine monitoring system comprising data logging means mounted or to be mounted on a machine for logging certain operational data relating to the machine, communication means for

collecting the logged data from the data logging means and means for storing the collected data for analysis or review.

By logging data in that way, it is possible, for example, to record the length of time taken to complete a particular operating cycle of the machine. Also, the data logging means may be used to record the date on which the machine is operated and, if desired, the time of day at which the machine is operated.

Conveniently, the data logging means may be a module which, in use, is mounted on the machine. In such a case, the module may be simply bolted to one side of the machine or at some other suitable position.

The data logging means may be miniaturised by utilising microprocessor surface mount components. In that way, the size of the data logging means can be kept to a minimum which is particularly advantageous where the data logging means is to be mounted on a portable machine.

Preferably, a signal is generated via the data logging means for indicating to an operator of a machine a certain operational condition of the machine. In that way, if the operating cycle of the machine has fallen outside a predetermined limit the operator receives a signal accordingly and can then send the machine for checking.

Although the monitoring system is passive and cannot directly influence the user of the machine, the user is, at least, given a signal indicating that attention is required.

In order to check whether or not the operator concerned is co-operating with the system, it will preferably be possible to tell from the analysed data if the operator has continued to operate the machine after the signal has been produced to indicate, say, that the operational cycle time is outside the predetermined limit. A signal may be generated by the data logging means for indicating to the operator of the machine that a certain step should be taken such as a dimensional check on a hole which is being formed using a machine. For example, where a drilling machine is being monitored, the latter signal may indicate to the operator that it is time to check the hole drilled with a"go/no-go gauge". Again, the analysed data from the data

logging means may indicate a failure on the part of the operator to heed the signal by continuing to operate the machine while the signal is still being produced. The aforesaid signals may comprise visual means such as flashing lights.

The aforesaid communication means may comprise a device to be positioned adjacent the machine to enable the logged data to be collected from the data logging means. The device may simply be clamped to the data logging means where the latter is mounted, say, on the external casing of the machine.

Conveniently, the data may be passed from the data logging means to the device by means of a electromagnetic radiation such as an infrared signal.

The device may be connected to the means for storing the logged data. The means for storing the logged data may be in the form of a suitably programmed PC.

A calibration station may be provided to enable the machine to be calibrated for a particular mode of operation. Calibration data preferably includes maximum and/or minimum operational cycle times for the machine which may be predetermined.

A time above the maximum calibrated cycle time may be transmitted to and stored in the data logging means to provide an operator maximum cycle time. Similarly, a time below the minimum calibrated cycle time may be transmitted to and stored in the data logging means to provide an operator minimum cycle time. The operator maximum and/or minimum cycle time may be transmitted via the communication means. Those additional times are preferably predetermined. The calibration cycle times and the additional times are preferably held within a personal computer (PC) for use by a setter.

As the operator uses the machine, if the cycle time for, say, drilling a hole increases beyond the maximum set operator cycle time, one of the aforesaid signals will be given to indicate that the machine requires attention. Similarly, the communication means can transmit data to the data logging means for setting times at which an

operator of the machine should take certain steps such as checking hole dimensions as described above.

Where a signal is generated via the data logging means for indicating to the operator a certain operational condition of the machine, the signal may be generated when the cycle time is outside the operator maximum or minimum cycle time.

Preferably, the data which sets out timing for an operator of the machine to take a certain step is transmitted to and recorded in the data logging means.

At least some of the data is supplied to the data logging means via a sensor which senses variation of pressure in accordance with a pneumatic logic signal for the machine.

Data transmitted to the data logging means by the communication means may include minimum and/or maximum operation cycle times for the machine.

Preferably, analysis means processes the logged data to provide information relating to any one or more of the following: cost per operating cycle the number of operating cycles per work shift : tool performance (for example the number of operations performed by a given tool driven by the machine) machine utilisation (e. g. how much use has been made of the machine during a particular workshift) machine availability machine history

Conveniently, the logged data may also be processed to provide maintenance information relating to the machine such as any one or more of the following: machine repair history parts and manpower repair costings strategies for preventative and/or predictive maintenance machine design improvement possibilities repair cost allocation Where, say, the system is being used in a factory having a computer network, the network server may receive the data collected from the data logging means and from which the data will be available at selected stations on the network. In such a case, data may be downloaded from several data logging means on respective machines, the data being held by the server on the network and making the data available at the various selected stations on the network.

The system is particularly, but not exclusively, directed at the monitoring of pneumatically operated machines. In such a case at least some data is supplied via a sensor which senses whether or not there is air pressure present for driving the machine.

The machine is preferably in the form of a drilling machine which may have automatic drilling cycles.

According to another aspect of the invention, there is also provided a method of monitoring a machine comprising logging operational data relating to the machine, collecting the received data and storing the collected data for analysis.

Preferably, the method includes utilising the elements of the monitoring system as set out in the first said aspect of the invention or any of the consistory clauses relating thereto.

A monitoring system in accordance with the invention will now be described by way of example with reference to the accompanying drawings in which: Figures 1 and la are perspective views of pneumatically powered drilling machines having an automatic drilling cycle; Figure 2 shows a perspective view of a data logging module for attachment to a drilling machine; Figure 3 is a diagram illustrating an overview of the monitoring system in accordance with the invention ; Figure 4 is a diagram illustrating a set-up part of the system for calibrating a module; Figure 5 shows a PC monitor screen display when set to calibrate the module; Figure 6 shows the monitor screen illustrating the display when a problem has arisen with the machine, Figures 7 to 11 are diagrammatic representations of various components of the system; Figures 12 and 12A show a flow chart of software in a machine mounted module and Figure 13 shows a flow chart for a computer used in the system.

Looking at Figure 1, a drilling machine 10 is a portable pneumatically powered type having a connector 12 which snaps into a high pressure airline of known kind, a handle 14 having a trigger 16, a body 18 carrying a mandrel 20 and a drive member (not visible in Figure 1) for carrying a drill bit. In use, the mandrel 20 is inserted into a previously drilled hole in a workpiece 21 (Figure 2). With the mandrel in position the operator squeezes the trigger 16 which begins a drilling cycle, the

mandrel expanding in its hole in known manner to provide a reaction to the force of the drilling operation. Rotation of the drill is started automatically followed by an automatic advance stroke during which the drill penetrates the workpiece 21. The advance stroke is followed by a retract stroke marking the end of the cycle. The mandrel 20 is then removed from the hole and placed in the hole drilled as described above so that the next hole can be drilled. Automatic drilling cycles as described are well-known. Figure 1 a shows another form of pneumatically operated drill and parts corresponding to parts shown in Figure 1 carry the same reference numerals and are not described in detail. In both instances, an upper steadying handle 22 is provided.

Looking at Figure 2, a module 24 (shown in position on the drilling machine 10 to Figure 2) comprises a housing 26 having mounting lugs 28 thereon. Light emitting diodes 30,32 are provided on a face 36 of the module for transmitting/receiving infrared signals. A light emitting diode 37 is provided on the face 36 and a similar light emitting diode 38 (see Figure 3) is provided on an opposite face 40. The light emitting diodes 37,38 provide visible light signals. A small bore flexible tube 42 connects an air pressure to electrical signals sensor 44 in the housing 26 which senses pneumatic logic signals from the air used to power the machine. The pneumatic logic signals which can be expected during the drilling cycle can be obtained from data supplied by the manufacturer of the drilling machine concerned.

The module 24 is powered by a battery such a lithium cell. The air pressure is picked up from an air logic unit on the machine as supplied as standard by the machine manufacturer.

Using the signals from the sensor 44, circuitry 45 in the housing 26 records the length, in seconds, of every drill cycle. Also, using microprocessor surface mount components, it is possible for the circuitry 46 to provide a miniature data logging unit. As well as being able to record the length of each drill cycle, the data logging unit can also be arranged to record the time and date of each hole drilled.

Looking at Figure 4, four communication devices 46 are provided in the present example. Each communication device 46 is arranged to be mounted on a drill mounted module 24 and has two infra red light emitting diodes 46a, 46b (see Fig 11) which align with the light emitting diodes 30,32 on the module to enable infrared light to be transmitted between the communication device 46 and the module 24.

A PC 48 having suitable software is used as the system controller and communicates with a power supply and signal distribution unit 50 via an interface (not shown) which provides digital and serial signals for the system. The unit 50 receives power from a suitable power supply such as normal AC mains. Four stations 52,54,56 and 58 can be controlled via the power supply and signal distribution unit 50 and form part of a general set-up area 59 (Figure 3) for the drilling machines. The station 52 is configured to log all machines which come back to and leave the set-up area and stations 54,56 and 58 are calibration stations for individual communication devices 46. The calibration stations 54,56 show a calibration display when the communication devices 46 connected thereto are not mounted on respective modules 24. On both displays, the upper figures 60 designate the day and month (0107), the middle figures 62 indicate time (1526) and the lower figures 64 indicate the year (1998). When a communication device is mounted on a module 24, the time and date recorded in the module will automatically be synchronised with the time in the PC 48.

The set-up area 59 is used to calibrate the modules 24 and, initially, a communication device 46 will be mounted on a given module 24 on a drilling machine 10 as shown at station 58. Assuming that the module 24 is being set up from scratch, the serial number of the drilling machine and the machine type on which the module 24 is mounted will be transmitted into a memory of the circuit 46 in module 24 using the PC 48. That information is then held within the module 24 permanently. Again, using the PC 48 a machine setter can now calibrate the machine. The calibration display on the screen of the computer monitor is shown in

Figure 5 and displays menu options 65,67 for the particular drilling machine on which the communication device 46 is mounted. The setter is now able to select the required operation and, for simplicity, a four button menu pad 59 is provided in place of the more complex keyboard of the computer 48. The first two buttons "Up"and"Down"enable the setter to move up and down within the menus. The "Back"button enables the setter to move between menus and the"Enter"button enables the setter to enter selected information. In figure 5, drill serial number P2- 1005 is set to be calibrated having automatically recognised that serial number from the module 44. After pressing the enter button the setter then moves down a menu 69 at the bottom of the screen to select the appropriate pre-loaded calibration details and then presses the"Enter"button. The lower menu displays a diameter of holes to be drilled, the length of the holes to be produced, the maker of the particular drill bit, the minimum and maximum operator cycle times in seconds as described below and the number of holes the drill should be in use to produce before a go/no- go check is made.

The pre-loaded calibration details will have been previously worked out by trial and error and the details entered in the computer 48 for use when a setter sets up or checks the drilling machine. The predetermined calibration cycle times appear at the top and bottom of a display unit 70, in this case, 16 seconds and 13 seconds indicating the maximum and minimum cycle times. To ensure that a machine to be issued to an operator is working within specification, the setter causes holes to be drilled in a two test plates or sheets of metal eg light alloy, the sheets being of different hardness, for example, corresponding to upper and lower skins of an aircraft wing. The drilling is performed with a communication device 46 in place on the module 24 and the cycle times (14.4 seconds being shown) appear on the display unit 70 between the upper and lower cycle times. Provided that the cycle times are between the upper and lower limits, the setter knows the drilling machine is operating within specification. If a cycle time is within specification a green light emitting diode 90 illuminates. If a cycle time is outside specification, a red light emitting diode 92 illuminates.

When the drilling machine is being used on location in the factory, for example to drill holes in a skin of an aircraft wing, the maximum and minimum cycle times will vary depending on factors such as the sharpness of the drill bit, material hardness, the condition of the drilling machine etc. Previous calculations made by trial and error provide typical drilling cycle times in analogous drilling situations and those times are recorded permanently in the computer 48. The computer adds an acceptable time in excess of the maximum calibration cycle time to provide a maximum operator cycle time and an acceptable time below the minimum calibration cycle time to provide a minimum operator cycle time based on the calculations held in the computer memory. The maximum and minimum operator cycle times are transmitted from the communication device 46 to the module 44 via infrared signals so that the information is stored in the module 24. The date, time and year is also stored in the module 24 and, as mentioned above will be automatically synchronised with the time in the PC 48.

The calibration cycle times and the calculations on which the operator cycle times are based are accessible for modification only by a system administrator.

Other information can be transmitted to the module 24 by the communication device 46 at the set-up area. For example, where it is necessary to perform go/no- go checks on holes being drilled, the frequency of the check can be made part of the calibration according to the particular operation. For example, when drilling large holes, the module 24 may be calibrated to indicate to the operator that a check must be made every four holes and, for smaller holes, a check must be made every time twenty holes have been drilled.

In use the operator will use the drilling machine in a conventional way and provided that the drill cycle times remain within the operator maximum and minimum, the operator will continue to use the drill normally. However, if the module 24 senses that the drill cycle time is increasing to a point outside one of those limits, for example, due to a drill becoming blunt or the drilling machine developing a fault, the circuit 46 will cause the two LED's 34,38 to flash and indicate that the drilling

machine is now operating out of specification. The operator then returns the drill to the set-up area for attention. Where the go/no-go hole check is required, the same LED's will flash. Two different messages can be conveyed to the operator using different light on-to-off flashing rates. It will be appreciated that the system is passive and does not directly control the drilling machine. However, the system alerts the operator to take certain action and provided that the operator co-operates with the system, the drilling of potentially sub-standard holes can be prevented.

Preferably, circuitry in the modules 24 will continue to log if holes are drilled after the LED's 34,36 have indicated that the drilling machine is operating out of calibration. Where a go/no-go check is to be made, it will be necessary for the operator to cease use of the drilling machine, make the check and then resume use of the drilling machine if all is well. However, where an operator simply continues the drilling operation after the go/no-go signal has begun to flash, the circuitry 46 within the module 24 can continue logging the fact that holes are being drilled while those lights are still flashing thereby indicating that the operator has not ceased using the drilling machine 10 during the time that the check should be made.

Once a drilling machine 10 that requires attention is returned to the set-up area, the communication device 46 at station 52 is fitted to the module 24 on the drilling machine and the information within module 24 is collected using the infrared signals and downloaded through the station 52 to the PC 48 which displays the serial number of the returned drilling machine. The drilling machine 10 is examined to see what has given rise to the need for attention and the fault can then be logged on the computer. Using the menu pad, the setter selects"Faults"in the second column 67 of the menu. A third column 69 of the menu then appears (Fig 6) and gives the setter the opportunity of selecting either"Cutter"or"Machine".

In the example shown, the fault is the cutter itself as opposed to the drilling machine and the"Cutter"option has been selected. A fourth menu column 71 then appears and the setter can select the appropriate description of the cutter, in this case, the cutter is highlighted as"chipped". That information is then logged within the PC 48 as part of the history of that drilling machine.

If the problem cannot be identified and corrected by the setters, the drilling machine is logged out to a maintenance section 72 (see Figure 3). The maintenance section 72 has a PC 74 along with a menu pad 59 and a communication device 46. When the drilling machine 10 is returned, the maintenance section 72 can put its own communication device 46 on the module 24 of the drilling and can interrogate data relating to the drilling machine and, if necessary, carry out repairs. The maintenance section 72 will then normally input on to the records of the drilling machine part costs, repair costs and man-hour costs etc. relating to the drilling machine via a menu system and the communication device 46. It is also envisaged that preventative and predictive maintenance procedures may be developed having more accurate information about the various drilling machines. Also, the maintenance section may be able to target possible drilling machine design improvements having an accurate history of drilling machine faults and failures. In addition to suitable software, only one communication device 46, one menu pad 59 and one PC 74 would be required in the maintenance section 72.

Once the drilling machine has been repaired, it is then returned to the set-up area 59 for re-calibration.

Where the battery which powers the module 24 needs to be changed, it will also be necessary to re-enter the serial number of the associated drilling machine.

With the information received from the module 24 and knowing the total costs relating to a particular work shift, it is possible to calculate costs per hole drilled during that shift. It is also possible to know the number of holes drilled per workshift, holes produced per drill bit or other cutting tool, drilling machine utilisation, drilling machine availability, drilling machine history and tool performance and the data will be stored in a database. In that way, it is possible at an analysis section 76 to analyse the performance of drilling bits from particular manufactures so that comparisons can be made. A computer 78 with suitable software and using data from the database is provided to determine such the information from the given parameters.

It is envisaged that an existing network in a factory where the machines are used will include a server 76 which will allow full access to data concerning the individual drilling machines from any area in the factory for analysis.

At any time that a communication device 46 is fitted to a module 24, the information stored in the module 24 up to that point can be downloaded once bought back to the set up area 59.

Reference is now made to Figs 7 to 11 which show diagrammatically details of components of the system.

Fig 7 shows the signal distribution unit 50 which includes a voltage pre-regulator 80 and a power supply 81 for the stations 52,54,56 and 58. Power drivers 82 are provided for digital output signals received from the interface in the PC 48 and serial signal routing of transmitted and received signals is provided at 84.

Fig 8 shows station 52 which is an issue and receive display station configured to log all machines which come back to and leave the set-up area allowing a record to be kept of which machines are in the set up area, out for use by an operator or in maintenance. There are three light emitting diodes 86,87 and 88 signifying Wait, OK and Instruction. The"Wait"diode illuminates when logged data in the module 24 is still being downloaded via the communication device 46. When it has been fully downloaded, the Wait diode goes out and"OK"comes on. The communication device can then be removed from the module 24. If some special case occurs where, say, the battery in the module 24 is reading low, the "Instruction"diode will illuminate and the screen of the PC 48 will carry a message instructing the setter to change the battery. The procedure is followed when issuing a calibrated machine to and when receiving a machine from the operator. The various components and their connections are apparent from Fig 8. The 5 volt regulator powers the communication devices 46 and the circuitry of the station 52.

Fig 9 shows components of each station 54 to 58. Where cycle time for a drilling machine 10 needs to be checked, the communication device 46 is fitted to the

module 24. The setter then checks the cycle times as described above by drilling the metal plates. As described above, the green light emitting diode 90 will illuminate if the drilling machine is still operating within calibration and the red light emitting diode 92 will illuminate if outside the calibration. The 5 volt regulator powers the communication devices 46 and the circuitry of the stations 54 to 58.

Fig 10 shows components of one of each of the modules 24. A microprocessor 94 is used in conjunction with the other components illustrated, the circuitry 45 being powered by the lithium cell indicated at 96, the voltage of which is sensed by a sensor 98. Information transmitted and logged by the module 24 is stored in memory 98.

Fig 11 shows that each communication device 46 includes transmit and receive buffers 100,102 respectively associated with the two infrared light emitting diodes 46a and 46b which transmit and receive signals to and from the module 24.

Figs 12 and 12A show a software flow chart shows a sequence of operations in software of the module 24 including the calibration mode, the sequence of the latter being in the left hand column of the flow chart. In Fig 12a, the flow chart continues from point A in Fig 12 and shows the sequence of events leading to an error flag being set at 104 which causes the flashing of light emitting diodes 34,38 at 105 if the drilling machine is operating out of calibration. The sequence also illustrates at 106 the need for a go/no-go hole check, again by means of the light emitting diodes 34,38.

Fig 13 shows a flow chart for software in the PC 48 applicable when data is to be transmitted to or received from the module 24.