Technical Field

This invention relates to fasteners. In particular, this invention relates to a particular type of network of fasteners.

Background Art

Monitoring of equipment status is becoming increasingly important. As one example, an aircraft monitoring system has been introduced recently under the name "Airplane Health Management". The intention of such a monitoring system is to assist in streamlining aircraft maintenance and to minimise disruption to flight schedules.

A monitoring system such as the "Airplane Health Management" system desirably can carry out the functions of collecting data about the aircraft or other equipment being monitored and transmit the data to a central or remote processing system. For the aircraft example, the remote processing system may be on board the aircraft or it may be on the ground, so that problems, or potential problems, have already been identified before the aircraft lands. Maintenance can then be ready with the necessary labour schedule and/or parts to service the aircraft.

It is understood that aircraft maintenance is a significant cost, which at present is continuing to increase. It is also understood that a 10% reduction in maintenance costs may increase net profit by up to 40%.

It is an object of this invention to facilitate monitoring systems, especially monitoring systems in aircraft, but not limited to that application. It is a further object of this invention to enable not only monitoring but also a system which enables an action to be taken in response to the situation monitored.

Reference is made to International Patent Application No. PCT/AU2003/000759, (the contents of which are incorporated herein by reference) which was published as W02004/001235 ("the International Patent Application"). The International Patent Application discloses in its second aspect a network or system of fasteners, in which each fastener includes an address means to distinguish that fastener from the other fasteners in the network. The fastener can be any fastener, including the fastener disclosed in the first aspect of the invention in the International Patent Application.

The fastener in that first aspect may be intelligent and may have a second function which makes use of the intelligence or switching capacity of the fastener. An example is given of a vehicle which has several of the fasteners in intelligent form. The fasteners have a first function which enables the fixing and releasing of light bulbs in the vehicle. The fasteners have a second function, which is to sense the amount of ambient light and to turn the light bulbs on or off depending on the amount of light sensed. Data as to the amount of ambient light is sent to a central processor which activates the fastener according to desired criteria as to automatic switching on or off of the lights.

The International Patent Application also discloses that the fastener may include a sensor able to convey information as to the condition of the fastening element included in the fastener in one embodiment and the actuating means (in the same embodiment). The sensor may sense the current state of the fastening element (engaged or disengaged). The sensor may sense to allow optimised control of the application of energy to the actuation means. The sensor may sense in order to report performance, degradation or impending failure of the fastening element or actuation means.

Disclosure of the Invention

The invention provides a fastener for use in a network of fasteners, the fastener including an address means to distinguish the fastener from the other fasteners in the network and being adapted for distribution throughout the assembly, either: •

(i) in an ordered pattern; or

(ii) to form a three-dimensional network; or both. The invention also provides a network of such fasteners, also referred to below as a "system".

The present invention represents a further aspect of the network of fasteners disclosed in the International Patent Application: In this further aspect, the network of fasteners has one or more of the following characteristics.

(a) the fasteners are distributed throughout an assembly in an ordered pattern;

(b) the fasteners are distributed throughout an assembly to form a three dimensional network.

As already indicated in the International Patent Application, the fasteners may be any suitable fasteners, including those disclosed in the International Patent Application.

The fastener may be any other suitable fastener. One example is the bolt assembly forming subject of International Patent Application No. PCT/AU03/001539. Another example is the fastener forming subject of International Patent Application No. PCT/AU2004/000371. The contents of both specifications are imported herein by reference.

The address means is intended to enable a network system to identify the fastener, for the purpose of establishing communications and addressing commands, such as a command to cause activation of actuating means.

The fastener may have actuating means which is any suitable actuating means and which will depend to a large extent on the nature of the fastener. Examples of actuating means are as follows: magnetic (linear solenoid), magnetic (rotary solenoid), magnetic (linear actuator), magnetic (motor), piezo-electric, electrostatic, thermal (shape memory alloy), thermal (bimetallic), thermal (state change), pneumatic, hydraulic, chemical, pyrotechnic or explosive, acoustic or ultrasonic, ionising radiation, ionising particles, luminescent and gravitational. The address means may be any suitable means but preferably is capable of storage in a non-volatile manner, in order to resist corruption and intentional or unintentional over¬ writing or reprogramming. It is also preferred that the address means does not enable more than one fastener to have the same identity, unless there is requirement for a replacement fastener to assume the same identity as the original fastener being replaced.

By way of non-limiting example, the address, means may comprise a serial number, a communications address or a temporary communications address, or any combination of these.

When the address means is a serial number,, this is preferably a unique number which is programmed into the fastener as part of the manufacturing process and which consequently does not change throughout the life of the fastener.

When the address means is a communications address, this is preferably a communications or network address which may be assigned to the fastener at the time of installation, or when the network is configured.

When the address means is a temporary communications address, this is an address which may be assigned to the fastener on a transient basis. This may be desired, for example, where the fastener is configured in a sub-network and use of the full, unique address of the fastener during a particular session will cause excessive communications traffic and/or require excessive processing overhead during the communication session.

The address means may enable the unique identity of the fastener to be stored in any suitable way, and in any suitable storage device. Preferably, the storage method is robust and uses known techniques, such as multiple redundant storage with checksum or CRC protection, reinstatement of backups on detection of errors, etc. Preferably, the storage method includes measures to prevent unauthorised access or tampering with the unique identity. .

Examples of storage devices are following: Hardwiring: this includes switches,jumpers, solder blobs and soldered links.

Non-volatile memory: this includes PROM (programmable read only memory), EPROM (erasable programmable read only memory), EEPROM (electrically erasable programmable read only memory), Flash memory, battery backed Tandom access memory (RAM), ferromagnetic RAM and optical storage. Storage of the unique identity may be combined with the operating program code of a microcontroller.

Semiconductor: storage in this form can incorporate the unique serial number programmed during manufacture and capable of being read by a microcontroller.

The address or identity of the fastener may be encrypted. There are many forms of available encryption techniques which may be suitable to the present invention. By way of example, the following are mentioned.

The first example is link encryption, where each communications link in which the information may be intercepted is protected by encryption of information on that link. Information may appear unencrypted or "in the clear" at communications or control nodes, and may need to be protected by other means, such as physical access control - discussed further below - at those points.

The second example is end-to-end encryption, in which information is encrypted at its source and decrypted at its destination and does not appear "in the clear" at intermediate points in the communications links.

As a third example, both end-to-end encryption as well as transmission over individually encrypted links may be used to result in a hybrid system.

In relation to physical access control, it may be desirable to incorporate further security measures to prevent unauthorised access to a system or network of fasteners of the invention, especially where there is a high level of need to prevent any unauthorised party to control fasteners, change system settings or configurations or cause damage or disruption to the system for any reason. By way of example, fasteners may attach valuable items to a vehicle or attach a door to its surround so as to lock the door. Obviously in such circumstances unauthorised operation of the fasteners could allow theft of the valuable items or intrusion through the door to occur.

While file encryption is one way to prevent unauthorised entry into a fastener system, there are other ways of controlling access. Some non-limiting examples are set out below.

Physical access to a system and its elements may be prevented by physically isolating the system or making it difficult to locate. For example, wiring for the system can be disguised within the loom of a vehicle. As another example, spread spectrum wireless communication techniques can be used to hide radiated signals amongst radio noise. Use of spread spectrum wireless links or other communications methods, such as optical fibres, can make it difficult to intercept, modify, disrupt or jam commands or communications to the system.

By way of further example, secure methods of identification may be used. For example, biometric information techniques may be used to identify authorised personnel and/or systems. Electronic security certificates may be required to authorise access by computer based systems. Valid access may require confirmation by personnel or systems by a bi-directional handshake and identity confirmation process, or by such measures as call-back to an authorised telephone number or a network address, for example.

Byway of further example, access to and control of fasteners may require the operator or control system to take part in a dialogue with a master control/database for a specific access code, in order to allow control of the fastener. As well as such explicit authorisation, there may be tracking of the transaction. For example, the access code and fastener operation may be recorded in a time stamped log stored by the master control/database, by the fastener itself or by intermediate system elements. Retrieval of such logs can permit analysis for audit tracking purposes. In the system of the invention, each activating means may actuate one or more fastening elements. The system preferably includes a control means for controlling actuation of the actuating means, typically by energy from an energy source. Each control means may control one or more of the actuation means.

It is further preferred that the system of the invention includes an intelligent controller device for controlling the control means, and, through it, the actuating means, typically in response to an external stimulus. Each intelligent controller device may control one or more control means.

Also, in this system of the invention, it is preferred that there is an energy source for providing energy to the actuating means. The energy source may include local storage of energy, such as in a battery, or externally applied energy, or a combination of both.

The system may include a sensor, which is discussed below. The system may further include an external sensing means for determining and reporting, the condition of external elements, for example, relating to an element which is engaged by the fastener and the engagement condition.

The network may be constructed in any suitable manner. Preferably, the network forms a star or a daisy chain. When the network forms a star, a power switch or processor is located in the center of the star, with each of the fasteners being separately connected to the central power switch/processor. In the case of a daisy chain, the connectors are arranged in a series, with a power source in the chain. Optionally, a data feed may also form part of the chain, using the power cable or separate data cables.

Especially in the case of the network of fasteners, the fastener may include a sensor able to convey information as to the condition of the fastening element and the actuating means, including sensing the current state of the fastening element (engaged or disengaged), sensing to allow optimised control of the application of energy to the actuation means and sensing in order to report performance, degradation or impending failure of the fastening element or actuation means. A sensor may operate in a number of ways, such as by use of one or more limit switches which may employ electrical contact, magnetic, optical, capacitive or any other suitable sensing mechanism, to sense the current fastener condition (i.e., open, closed, intermediate or any one of a number of stable positions). Another example is one or more strain gauges or equivalent strain sensing devices which are installed on or in association with the fastener to sense position and condition and, having high levels of resolution, which can allow fine position determination and control. As another example, force sensors or force sensing devices maybe installed on or associated with the fastener, in order to sense the force exerted on or by the fastener, and the condition of the fastener, with high levels of resolution and once again allowing fine position determination and control. Proximity sensors or equivalent positioning sensing devices may be used to sense the position of the fastener. Temperature sensors or equivalent temperature sensing devices can be used to sense the temperature of the fastener and, depending on the fastener type, these may be used to optimise control of the fastener andto sense condition of the fastener. Other examples of sensors will be apparent to one skilled in the art.

As well as enabling reports as to fastener position and condition to other areas of a network system, sensors may be used to optimise fastener control operations. Non- limiting examples are as follows.

In a first example, sensors in the form of limit switches are used to sense movement of the beam to the disengagement position. Power is supplied at a high level to the actuating means until the disengagement position is reached, whereupon the limit switches report this position. At that stage, power can be reduced to a lower level, being still sufficient to sustain the fastener in the disengagement position. Operating time, energy consumption and heating is minimised.

In a second example, a strain gauge is attached to the beam. Power can be applied at a high level to the actuating means until the beam is deflected to the disengagement position. Detection of this position by the strain gauge enables the power to be reduced to a lower level, once again being sufficient to sustain the fastener in the disengaged position, but at the same time minimising operating time, energy consumption and heating. In addition, analysis of the degree of bending of the beam as a function of applied power andtime will allow degradation of the beam to be detected arid signal the need for replacement prior to complete failure.

As a variation on the second example, there may be two strain gauges on the beam, one on either side. Differential measurement allows the beam position to be determined throughout its travel, with high resolution. Common mode measurement can allow linear extension or compression of the beam to be measured and hence axial loading on the beam to be determined.

As a third example, sensors may sense the contents (or lack of contents) of fastened elements and provide an appropriate response. For example, if the elements joined by the fastener are pipes, a sensor may sense presence of fluid in the pipe and refuse to disengage the pipes, even if given a command to do so. Similarly, the sensor may sense electrical current in a cable joined by the fasteners and refuse to disengage if to do so would cause a dangerous situation.

In a further example, the sensor may be a local temperature probe, which can sense ambient temperature and report to an embedded processor. The processor could then calculate and distribute the appropriate amount of power required to activate the actuating means. Shape memory alloy is usually activated by a pulse of power, for example, a 1500C pulse of power. This works well if the ambient temperature is in the range of -5O0C to 75°C. However, if the ambient temperature is high, such as over 750C, the 1500C pulse of power may cause the shape memory wire to overheat. Consequently, the sensor, having sensed the ambient temperature, can enable the processor to work out and distribute the appropriate amount of power to the fastener, increase the operating temperature window of the system at lower ambient temperatures, or save power if the ambient temperature is already relatively high. The system may include status indication means (such as an LED or an audible signal), to indicate the current condition of the fastener or the external sensing means and/or any other aspect of the system.

Further, the system may include communication means for enabling an external device or system to communicate with the fasteners of the invention in the system, both for control and for status reporting functions.

In one preferred embodiment, the system of the invention includes one or more fasteners together with one or more control means, one or more sensors, an energy source, an intelligent control device, a status indicator and an external sensing means.

In an expanded form of the system, a plurality of fastener systems as per the last mentioned preferred embodiment is networked with one or more optional communications concentrators, one or more intelligent control units and one or more master control/database units. Examples of these are given below in connection with the drawings.

It will be appreciated that the invention in its various aspects set out above has particular application areas for product assembly, product disassembly, product recycling, product servicing and maintenance.

In relation to product assembly, disassembly and product recycling, application of the invention in its various aspects is useful in relation to automobiles, for example in connection with exterior trims and accessories, interior trims, air conditioning units, sound systems and auto-electrical subassemblies.

In relation to product servicing and maintenance, the fasteners of the invention can provide faster and more secure (because authorised) access to parts and subassemblies of products or equipment for the purposes of repair, replacement or maintenance. The fasteners can provide a significant saving in labour, since they can reduce the average time for repair. They can also provide a cost effective and secure method of access to internal components. The fasteners can reduce the need for skill, because the process of assembly and disassembly can be directed by a computer.

The fasteners may be networked in any way as disclosed above or in any other suitable ■ way. For example, the fasteners may be networked by hard wiring or by, for example, "blue tooth" communication or by other wireless means.

The fasteners may communicate with each other and/or with a central monitor, such as a computer, in any one or more of the following ways: by cable, by wireless link, by custom radio link, "Blue Tooth", "Zigbee", "Wifi" (802.11), inductive coupling, infra¬ red, microwave, visible light or using ultra-sound or other acoustic energy. Wireless link may be via an external system, which then communicates with the fasteners in the network, for example by global positioning system (GPS), by SMS or MMS, by GPRS or by Wifi to an internet access point.

The foregoing examples are not limiting with respect to the invention.

Preferably, the network of fasteners is distributed throughout the assembly so as to provide, essentially, a three dimensional model of the assembly.

The assembly can be chosen from a wide range of objects. For example, the assembly may be a building, a motor vehicle, an aircraft or any of a myriad of other objects.

Whether the fasteners are distributed throughout the assembly in an ordered pattern or to form a three dimensional network, it is not essential that every fastener in the network is multi-functional. However, it is preferred that every fastener is multi-functional.

The invention may be particularly useful in providing to a central monitoring point an environmental picture of all or most of the assembly at the location of each fastener. For example, a fastener or a group of fasteners may sense ambient temperature and compare this to the temperature sensed by another fastener or group of fasteners. The comparison may activate some of the fasteners. For instance, if the assembly is a building and a temperature differential is detected by comparison of the temperature Ϊ2

reports from various fasteners or groups of fasteners, air conditioning may be activated, or one or more windows in the building may be opened or closed, or both air conditioning and windows may be activated. This can provide automatic temperature control. The fasteners may take part in the activation, for example, by releasing a window biased to the open position. Alternately, the fasteners may report to an activating mechanism which then carries out the required task.

The network of fasteners may pass on other sensed data, for example to a computer which analyses and displays the real time situation against the ideal state. For example, the assembly may be a building and the network of fasteners may be used to adjust the lighting levels in response to natural light availability. As another example, the fasteners in the building may detect fire at an early stage, by sensing an unacceptable rise in temperature (and activate an alarm or water sprinklers, for example). The fasteners may report overstressing or damage to a fastener in the system and control the situation by increasing the level of fastening of adjacent fasteners or by activating a redundant fastener. The network of fasteners may function to release a particular part of the assembly in an emergency. For example, in case of fire or explosion, the network may instruct certain fasteners to release part of the assembly such as a beam or a door if this is calculated to reduce the seriousness of the outcome of the fire or explosion.

The fasteners may have a single function in addition to the fastening function, or some or all of the fasteners may have more than one additional function. For example, a fastener may be both heat sensitive and light sensitive as well as having its primary fastening function.

It will be apparent to one skilled in the art that the invention has an extremely wide range of application. Some further examples are referred to below. . It is to be understood that these are not limiting on the scope of the invention.

The assembly may be the hull of an oil tanker. The network of fasteners may be adapted to detect breach to the hull and generate an alarm. The network of fasteners may be built into the frame of an aircraft and sensitive to changes in temperature; thus being able to detect, at an extremely early stage, that a fire has started, for example in an electrical system. The generation of an alarm at this early stage can enable swift action to prevent major damage.

5 The network of fasteners may be built into the body of a military vehicle and be adapted to detect the presence of chemicals or adverse biological conditions, and cause action to be taken to ensure the safety of the occupants or generate an alarm.

Especially in the case of the fasteners disclosed in the first aspect of the International Patent Application, the sensors may be incorporated in the fasteners in a very 0 economical manner. There can be virtually no extra costs in including a suitable sensor in the electronic chip controlling the fastener.

As indicated above, the response of the fastener to the sensor may be to release or ■ fasten, or may be to generate some other type of response, such as an alarm or activate another mechanism.

Brief Description of the Drawings

The invention will now be described in connection with certain non-limiting examples described in the attached drawings. In the drawings:

Figures 1 and 2 show in side and rear elevation respectively a first embodiment of a . fastener which can be used in connection with the invention;

Figures 3 and 4 show in side elevation and rear elevation respectively a second embodiment of such a fastener;

Figure 5 is a block diagram of an embodiment of fastener which can be used in the network or system of the invention;

Figure 6 is a block diagram showing an embodiment of a network of fasteners; Figure 7 is a block diagram showing a form of encryption.

. Figure 8 is another block diagram showing a different form of encryption;

Figure 9 is a block diagram dealing with address means;

Figure 10 is a perspective view of an aircraft showing an embodiment of network of fasteners according to the invention; and.

Figure 11 shows the network of fasteners of Figure 10 excluding the aircraft.

Detailed Description of the Drawings

In Figures 1 to 4, the size of the base to the fastener has been exaggerated for clarity of detail. These Figures show packaging and integration of intelligent forms of a fastener which may be used in the network of the invention. Other fasteners may be substituted.

Referring first to Figures 1 and 2, this embodiment of fastener is made of moulded plastic and the actuating means is a smart memory alloy wire. The fastener 10 has flexible beam 12 with at one end engagement means 14 and at the other mounting block 16.

Engagement means 14 is wedge shaped at 15 to engage a ledge (not shown), the engagement means on a second fastener or any other suitable surface.

When shape memory alloy wire 18 is heated sufficiently, it contracts, drawing wedge 15 out of engagement.

As can be seen from Figure 1, shape memory alloy wire 18 is attached to circuit board 112 and to a conductive base 113 for earth return connection . A single wire 114 carries power and superimposed communications and makes connection via an insulation displacement connector 116.

In the embodiment in Figures 3 and 4, fastener 10 clips into base 118. Wire 18 connects to printed circuit board 112, in this case integrated into fastener 10. Base 118 accommodates a four- way ribbon cable 120 which runs through base 118 and which is crimped into place. Cable 120 carried power and communication, with connection to fastener 10 by electrical contacts 122.

Figure 5 is a block diagram of an intelligent fastener configuration, applicable to the network of the invention when there are multiple fastening mechanisms. It is self- explanatory.

The block diagram in Figure 6 represents a system of fasteners. Each intelligent fastener is as shown in Figure 5. The communications concentrator, which is an optional element, provides a mechanism for partitioning system complexity, eg, by providing an interface between a relatively costly-to-implement radio frequency network and an inexpensive RS-485 network which interconnects a number of the fasteners via a subnetwork. The subnetwork may use any communications which may also be useful for the intelligent fastener, such as uni-directional, bi-directional, full duplex, half duplex, simplex, point-to-point, network, asynchronous and synchronous, via such techniques as electromagnetic radiation, radio (AM or FM), magnetic coupling, low frequency RF, microwave radio, spread spectrum radio, light (visible, infrared), optical fibre, electrical (wire, cable) or sonic (ultrasonic, audible or infra-sound).

The intelligent control unit may be a discrete device, an integrated circuit, a microcontroller, a microcomputer, a programmable logic device, a hybrid integrated circuit, an application specific integrated circuit, a printed wiring assembly or an embedded PC.

The optional sensing mechanism may be binary, multi-state or linear and operate by any of the following techniques: electrical (switch, contact, strain gauge, piezo-electric, piezo-resistive, magneto-resistive, resistive), magnetic/Hall effect, capacitive, optical acoustic/ultrasonic or mechanical.

The status indication may be optical, acoustic or mechanical. The control mechanism may also be binary, multi-state or linear. Jt may operate by techniques such as electrical (swirch, relay/contactor, semiconductor, transistor, FET, fhyristor, mechanical (lever, valve, piston) or biological (human or animal).

The energy source and optional storage may be local, external or a combination, using a technique such as primary or secondary cell or battery, mains derived power, capacitor or supercapacitor, electromagnetic radiation (RF or light), inductive coupling, acoustic, chemical, fuel cell, gravity, mechanical, kinetic or biological.

Turning now to Figure 7, this illustrates a form of link encryption, in which each communications link where the information (address data) may be intercepted is protected by encryption of information on that link.

Figure 7 shows a form ofend-tq-end encryption, where information is encrypted at its source and decrypted at its destination.

Figure 9 shows storage of a unique identity for a fastener, using a" microcontroller-based intelligent controller which incorporates internal program code memory programmed with a unique serial number during manufacture. Also included is an EEPROM which stores a network address programmed as part of installation and commissioning. Each of these is stored redundantly with checksum protection.

Figure 10 shows an assembly which is an aircraft 210 having a network of fasteners 220 (refer Figure 11) distributed throughout the aircraft. Each fastener 212 (some only are labelled) has a primary function of holding the aircraft assembly 210 together. The fasteners 212 are within some cases within the aircraft 210, in other cases just beneath the internal or external skin 214 of the aircraft 210 and in other cases penetrating the skin 214 (similarly to a rivet) on a conventional aircraft assembly.

It is an option that other fasteners (not shown) are included in aircraft 210 but are not part of the network of fasteners 220. Some of these fasteners which are not part of network of fasteners 220 may be present in case of need (redundancy) or may not be part of the network of the fasteners 220 for some other reason. Fasteners 212 in network 220 may, for example, report on whether those fasteners 212 which hold engine 216 to mounting 218 are stressed in any way. If any stress is detected, other fasteners 212 in the vicinity of the stressed fasteners may increase the degree of fastening in order to make up for any shortcoming in fastening by the stressed fastener or fasteners.

Similarly, fasteners 212 located between skin 214 and the aircraft lining (not shown) may report on any significant rise in temperature, which may indicated commencement of a fire, for example in electrical cabling.

Industrial Applicability

As the above description amply demonstrates, the invention in its various aspects . represents a major advance in the art and is readily applicable industrially.