PROXIMITY DETECTION SYSTEMS AND METHODS
FIELD OF THE INVENTION
[0001 ] The present invention relates to proximity detection systems and methods. In particular, the invention relates to proximity detection systems and methods for assisting operators of mobile plant and personnel working on the ground in close proximity to maintain a safe distance between each other. However, it will be appreciated that the invention may be useful in other areas and applications.
BACKGROUND TO THE INVENTION
[0002] Reference to background art herein is not to be construed as an admission that such art constitutes common general knowledge in Australia or elsewhere.
[0003] Fixed and mobile plant, such as forklifts, road transport vehicles, cranes, excavators, bobcats, dozers and graders, often present a significant injury hazard to personnel in the work environment. This is particularly prevalent when the vehicles are in operation in small areas where both pedestrians and vehicles share common work areas. As the vehicles are often large and heavy, even if travelling at slow speeds, any near miss or collision with pedestrians can be detrimental to the pedestrian, often resulting in post traumatic stress, debilitating injuries, severed limbs and even death. These accidents may also result in damage to surrounding structures and expensive plant equipment, resulting in shut down of the worksite impacting both productivity and revenue.
[0004] Some existing systems for detecting and warning of the presence of mobile plant and vehicles in proximity to pedestrians involve the use of fixed linear infrared beam detectors which trigger an alarm when the beam is interrupted or broken by a vehicle crossing the path of the beam.
[0005] A disadvantage of the infrared beam system is that it can be triggered by movement of pedestrians through the beam which produces false alarms. These false alarms can ultimately lead to complacency in pedestrians, rendering the system useless. Furthermore, coverage in an extended direction
and around large worksites is difficult and can be expensive to both install and maintain.
[0006] Another solution employs the use of a flashing light mounted on the vehicle or plant to draw more attention to the vehicle. This flashing light can also be coupled with a horn or reversing beeper to warn pedestrians of the proximity of the vehicle in high risk areas.
[0007] However, unless the flashing light is visible to a pedestrian, the usefulness of this system is significantly diminished. In addition, general noise on the worksite may obscure or make it difficult to hear a reversing beeper or horn.
[0008] Other existing systems utilise Global Navigation Satellite System (GNSS) technology, such as Global Positioning System (GPS), GLONASS and Galileo. However, such systems are typically only accurate to within approximately ± 2 metres in ideal conditions, and even less accurate in non- ideal conditions. These inaccuracies become particularly pronounced as a person gets closer to plant, which can cause GPS signal distortion and, ultimately, accidents and injuries when mobile plant collides with a worker.
[0009] Alternative known systems utilise time of flight (TOF) to locate personnel on construction sites and the like. Such systems require position locating devices to be fitted to hats worn by personnel, a master station and a plurality of site sensors, for example around at least a periphery of the site, for the system to operate, which can be expensive to both install and maintain.
[0010] The Applicant previously developed a system which utilised GPS technology and wireless ranging at 2.4Ghz. However, this system proved problematic due to low penetration through obstacles, such as walls, and a lack of reliability and accuracy due to multipathing.
SUMMARY OF THE INVENTION
[001 1 ] In one form, although it need not be the only or indeed the broadest form, the invention resides in a proximity detection system comprising:
a plant proximity detector comprising at least one wireless transceiver and a position sensor and defining a detection zone, wherein at least one of the one or more wireless transceivers of the plant proximity detector is a Bluetooth Low Energy (BLE) transceiver;
a personnel proximity detector comprising one or more wireless transceivers in communication with the wireless transceiver of the plant proximity detector, wherein at least one of the one or more wireless transceivers of the personnel proximity detector is a Bluetooth Low Energy (BLE) transceiver; and
a display unit in communication with the plant proximity detector and the personnel proximity detector;
wherein an alert is issued by at least one of the display unit, the plant proximity detector and the personnel proximity detector if the personnel proximity detector is detected within the detection zone.
[0012] Preferably, the position sensor of the plant proximity detector is a Global Navigation Satellite System (GNSS) sensor in communication with a GNSS antenna.
[0013] Suitably, the personnel proximity detector further comprises a position sensor in the form of a Global Navigation Satellite System (GNSS) sensor.
[0014] Preferably, the one or more wireless transceivers of the plant proximity detector and the personnel proximity detector further comprises a radio frequency transceiver, such as a 900MHz radio frequency transceiver.
[0015] Suitably, a plurality of plant proximity detectors is coupled to fixed or mobile plant, the plurality of plant proximity detectors connected in a network, in particular over a controller area network (CAN) bus network.
[0016] The plurality of plant proximity detectors defines a plurality of detection zones about the fixed or mobile plant and preferably the plant proximity detectors are tuneable to define an area or region covered by each detection zone.
[0017] Suitably, an alert is issued by at least one of the display unit, the plant proximity detector and the personnel proximity detector if the personnel proximity detector is detected within one or more of the plurality of detection zones.
[0018] The system may comprise a plurality of personnel proximity detectors associated with a plurality of personnel, wherein a signal is relayed to every personnel proximity detector within range and/or every plant proximity detector within range when any one of the plurality of personnel proximity detectors is detected within a detection zone.
[0019] Preferably, position information determined by one or more of the Global Navigation Satellite System (GNSS) sensors is communicated between the display unit and the one or more personnel proximity detectors via the radio frequency transceivers.
[0020] In some embodiments, the display unit, the plant proximity detector and the personnel proximity detector each comprise an ingress protected housing having an ingress protection rating of IP54 or IP65.
[0021 ] In some preferable embodiments, the display unit is in communication with an alert indicator, such as a light or siren, for example, which is activated when one of the at least one plant proximity detectors detects one of the at least one personnel proximity detectors within a detection zone of the at least one plant proximity detectors.
[0022] Preferably, the system comprises a plurality of plant proximity detectors and a plurality of personnel proximity detectors.
[0023] In some particularly preferred embodiments, each personnel proximity detector comprises one or more visual indicators for indicating various conditions or states of at least one of the personnel proximity detectors. In some embodiments, the one or more visual indicators are in the form of light emitting diodes (LEDs).
[0024] Preferably, each personnel proximity detector comprises one or more feedback indicators for indicating various conditions or states of at least one of the personnel proximity detectors by providing audio or haptic stimulation.
[0025] In some suitable embodiments, the proximity detection system further comprises a computer readable storage medium adapted to log events and track personnel and plants.
[0026] In another form, the invention resides in a method for detecting plant and personnel and assisting plant operators and personnel in close proximity to maintain a safe distance between each other, the method comprising the steps of:
securing at least one plant proximity detector to plant, wherein each plant proximity detector has one or more wireless transceiver and a position sensor, wherein each plant proximity detector is in communication with a display unit and wherein at least one of the one or more wireless transceivers of the plant proximity detector is a Bluetooth Low Energy (BLE) transceiver;
providing a personnel proximity detector to personnel, wherein the personnel proximity detector has one or more wireless transceivers in communication with the wireless transceiver of each plant proximity detector, and the personnel proximity detector is in communication with the display unit, wherein at least one of the one or more wireless transceivers of the personnel proximity detector is a Bluetooth Low Energy (BLE) transceiver;
configuring a detection zone around each plant proximity detector via the position sensor of the plant proximity detector;
issuing an alert to at least one of the plant proximity detector, the personnel proximity detector and the display unit when the personnel proximity detector is detected in the detection zone of the plant proximity detector.
[0027] Further features and advantages of the present invention will become apparent from the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] To assist in understanding the invention and to enable a person skilled in the art to put the invention into practical effect, preferred embodiments of the invention will be described by way of example only with reference to the accompanying drawings, in which:
[0029] FIG. 1 illustrates a block diagram of a proximity detection system in accordance with an embodiment of the present invention;
[0030] FIG. 1A is a block diagram of a close proximity beacon receiver for fixed and mobile plant used in the system shown in FIG 1 ;
[0031 ] FIG 1 B is a block diagram of a close proximity beacon worn or otherwise carried by personnel used in the system shown in FIG 1 ;
[0032] FIG 1 C is a block diagram of a GNSS proximity device worn or otherwise carried by personnel used in the system shown in FIG 1 ;
[0033] FIG. 2 illustrates a block diagram of the proximity detection system showing the detection zones in accordance with an embodiment of the present invention; and
[0034] FIG. 3 is a general flow diagram illustrating methods in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0035] Elements of the invention are illustrated in concise outline form in the drawings, showing only those specific details that are necessary to understanding the embodiments of the present invention, but so as not to clutter the disclosure with excessive detail that will be obvious to those of ordinary skill in the art in light of the present description.
[0036] Referring to FIG. 1 , there is illustrated a block diagram of a proximity detection system 10 for assisting operators of fixed or mobile plant and personnel working, for example, on the ground, in close proximity to maintain a safe distance between each other with the aim of preventing accidents, injuries and deaths.
[0037] The proximity detection system 10 comprises a display unit 100, plant proximity detectors in the form of, in this example, five close proximity beacon receivers 200 and a head unit 300. The system 10 also includes personnel proximity detectors in the form of a close proximity beacon 400 and a GNSS proximity device 500, both of which are worn by personnel 1 1 , in the present embodiment. Whilst close proximity beacon 400 and a GNSS proximity device 500 are shown as separate devices in this embodiment, it should be appreciated that they can be integrated into a single device.
[0038] In the illustrated embodiment, the display unit 100 connects to and communicates with the close proximity beacon receivers 200 and the head unit 300 through a breakout box 600 which receives signals from the display
unit 100, the close proximity beacon receivers 200 and the head unit 300, which is mounted to plant 700, which can be fixed or mobile, such as an excavator, crane or forklift, for example.
[0039] As can be seen, the breakout box 600 connects to both the display unit 100 and the head unit 300 via, for example, serial RS 484 connections 610, 620, and connects to the close proximity beacon receivers 200 over a network, and in particular over a controller area network (CAN) bus network 630.
[0040] In addition, the breakout box 600 interfaces with an alert system 710 of the mobile plant 700 via a digital I/O connection 640. The alert system 710 can comprise a number of different systems, such as a flashing light and/or siren, for example, which can be activated under certain predefined conditions, such as a worker entering a detection zone.
[0041 ] The display unit 100, which can be located within a cabin of the mobile plant 700 or in a control room of the fixed plant, comprises an IP54 rated housing 105 having a display device in the form of a backlit Liquid Crystal Display (LCD) touchscreen 1 10. The display unit 100 displays a graphical user interface which can be used to navigate through various menus, viewing options and for inputting data as well as displaying the location of proximate personnel and machinery relative to the mobile plant 700. While the housing 105 is described in this embodiment as having an ingress protection rating of IP54, it will be appreciated that the housing 105 could have no ingress protection at all or could have ingress protection as high as IP69k.
[0042] The display unit 100 also internally comprises a removable and rechargeable battery, such as a Lithium-Ion battery, which powers the display unit when being used away from an AC power source 1 15.
[0043] In some embodiments (not shown), the display unit 100 can further include connectors, in the form of ethernet, CAN bus, serial bus (such as
RS485) or the like, so that the display unit can be connected to a network and other devices, such an external loudspeaker, for example.
[0044] There is also a ball and socket mounting device (not shown) located on the outside of the housing 105 allowing the display unit 100 to be mounted to a window or a dashboard of a vehicle and oriented as required.
[0045] Turning to the close proximity beacon receiver 200, and with additional reference to FIG 1A, each close proximity beacon receiver 200 comprises a removably attachable IP65 rated housing 205 internally housing a Bluetooth low energy (BLE) transceiver 210, which allows for the detection of personnel up to 30m away and continues to function even when GNSS reception is poor, inaccurate or not available. It will be appreciated that while the housing 205 is described in this embodiment as having an ingress protection rating of IP65, the housing 205 could have no ingress protection at all or could have ingress protection as high as IP69k.
[0046] As can be seen in the illustrated embodiment, there are four close proximity beacon receivers 200 spaced equidistantly around the perimeter of the plant 700 and a fifth close proximity beacon receiver 200 located within the plant 700. The five close proximity beacon receivers 200 are connected via input/output ports 225 to a CAN bus 630 allowing for multiple detection zones to be setup. It has been found that the detection zones (illustrated in FIG. 2) can be calibrated, tuned or otherwise configured to provide detection of personnel from 1 metre to 30 metres away. As a result, it can be accurately identified where personnel are located relative to the plant 700, i.e. behind, beside, in front, underneath or overhead. It will be appreciated that fewer than five, or more than five close proximity beacon receivers 200 can be used depending on the application and the configuration of the detection zones required.
[0047] Each close proximity beacon receiver 200 also has a surface mounting device220 for mounting the close proximity beacon receiver 200 to a surface, such as the outside of the plant 700. The surface mounting device 220 can be in the form of a magnetic mount or another mounting means, for example requiring one or more fasteners.
[0048] The head unit 300, located on the plant 700, comprises an IP65 rated housing 305 which internally houses a Global Navigation Satellite System (GNSS) sensor and GNSS antenna 320, and a 900MHz radio frequency transceiver 31 1 for communicating with the GNSS proximity device 500. It will be understood that housing 305, in some embodiments, could have no ingress protection at all or could have ingress protection as high as IP69k.
[0049] The internally housed radio frequency transceiver 31 1 is connected to an extendable external antenna 310 located on the outside of the housing 305, which can be retracted and folded down to avoid breakage or damage when not in use or not needed. In some embodiments, the extendable antenna 310 can also be removed.
[0050] The head unit 300 further includes a digital compass 330. This combination of the GNSS sensor 320 and the radio transceiver 31 1 allows the plant 700 to accurately locate other machines as far away as up to 1500m and personnel up to 500m.
[0051 ] Both the close proximity beacon receivers 200 and the head unit 300 can internally house a removable and rechargeable battery 215, 315 respectively, such as a Lithium-Ion battery, which powers the receivers 200 and unit 300 when being used away from an AC power source.
[0052] Additionally, the head unit 300 has a surface mounting device, such as a bracket for mounting the head unit 300 to a surface, such as the top of mobile plant equipment or the roof of fixed plant.
[0053] With additional reference to FIG 1 B, the close proximity beacon 400, worn by personnel 1 1 , includes an IP65 rated housing 405 which internally houses a Bluetooth low energy (BLE) transceiver 410 and a 3 volt rechargeable lithium-ion battery 415. Attached to the housing 405 is an armband 420 which allows personnel 1 1 to securely attach the close proximity beacon 400 to themselves.
[0054] With additional reference to FIG 1 C, the GNSS proximity device 500, also worn by personnel 1 1 in the illustrated example, includes an IP65 rated housing 505 which internally houses a Global Navigation Satellite System (GNSS) sensor 515, such as Global Positioning System (GPS) or a GLONASS sensor and a 900MHz radio frequency transceiver 520 which communicates with the 900MHz radio frequency transceiver 31 1 of the head unit 300.
[0055] In some embodiments, the GNSS proximity device 500 also includes a Bluetooth low energy (BLE) transceiver 510. In these embodiments, the combination of the GNSS sensor 515 and the Bluetooth low energy (BLE) transceiver 510 allows for the detection of personnel in close
proximity to the plant 700 and continues to function even when GNSS reception is poor, inaccurate or not available.
[0056] To allow the GNSS proximity device 500 to be worn, the GNSS proximity device 500 has a mounting device, such as an armband or lanyard 530 which allows the GNSS proximity device 500 to be attached to, for example, a helmet 12 of the personnel 1 1 .
[0057] Also housed within the housing 505 is a 3 volt rechargeable lithium- ion battery 525 to power the GNSS proximity device 500.
[0058] In some embodiments, the close proximity beacon 400 and/or GNSS proximity device 500 have one or more respective visual indicators 440, 540, such as light emitting diodes, for indicating various conditions or states of the respective devices.
[0059] The close proximity beacon 400 and/or GNSS proximity device 500 can also include one or more respective feedback indicators 445, 545 for indicating various conditions or states by providing audio or haptic stimulation. For example, the close proximity beacon 400 and/or GNSS proximity device 500 can include a vibrating motor for creating vibrations in the device to be felt or heard by a user. Additionally, or alternatively, the close proximity beacon 400 and/or GNSS proximity device 500 can include a speaker for creating sounds, such as beeping, to be heard by a user.
[0060] It will be appreciated that in some embodiments, the functionality of the close proximity beacon 400 and the GNSS proximity device 500 can be integrated into a single device. Such integration requires personnel to wear or otherwise carry a single device rather than two and reduces the component count.
[0061 ] To use the proximity detection system 10, the display unit 100 and head unit 300 are located in the fixed or mobile plant 700. A number of close proximity beacon receivers 200 are then placed at predetermined locations around or on the fixed or mobile plant 700.
[0062] As described above, the close proximity beacon receivers 200 are connected by a network 630, such as a CAN bus network which allows multiple detection zones to be set up. For example, a detection zone formed around the perimeter of the plant 700 can be established. Close proximity beacons 400 and GNSS proximity devices 500 are then distributed amongst
personnel 1 1 , and can be attached to the personnel 1 1 , held or otherwise kept on or near personnel 1 1 . In an example, the close proximity beacon 400 or GNSS proximity device 500 can be attached to a helmet, tether or lanyard to be worn around a person's neck or worn on an arm band.
[0063] The close proximity beacons 400 and/or GNSS proximity devices 500 are fitted with indicators 440, 445, 540, 545 (including visual indicators, audio indicators and tactile indicators, for example) which are activated when personnel 1 1 having a close proximity beacon 400 and/or GNSS proximity device 500 enters a detection zone around the plant 700. In some embodiments, a signal can also be relayed to every close proximity beacon 400 and GNSS proximity device 500 within a wireless range when any one close proximity beacon 400 or GNSS proximity device 500 enters a detection zone.
[0064] When a close proximity beacon 400 or GNSS proximity device 500 is detected within a detection zone, the display unit 100, via a graphical user interface, displays the location of the close proximity beacon 400 or GNSS proximity device 500 relative to the close proximity beacon receiver 200 and identifies the detection zone that has been breached.
[0065] In some embodiments, the GNSS proximity devices 500 can be programmed with geofences that, when entered, will trigger an alarm to be raised. Advantageously, this warns a worker they have entered a restricted or high risk area.
[0066] In an example, illustrated in FIG. 2, there are three defined detection zones: a warning zone 800, an alert zone 810 and a close proximity zone 820. It will be appreciated that the zones 800, 810, 820 can be adjusted to suit particular needs, for example, in view of the type of plant and level of mobility. As an example, mobile plant that can move quickly is likely to require a larger warning zone 800 to provide sufficient time to both personnel 1 1 and plant operator.
[0067] In the illustrated example, when personnel 1 1 using a GNSS proximity device 500, which houses the GNSS sensor 515, enters the warning zone 800, the GNSS sensor located within the head unit 300 detects this, and issues a warning, such as a short beep or flashing light, for example.
[0068] If the personnel 1 1 proceeds closer to the plant 700 and into the alert zone 810, the head unit 300 again detects the location of the GNSS proximity device 500 using GNSS signals and issues an alert, such as a sustained tone, rapidly flashing light or vibrations, for example.
[0069] If the personnel 1 1 , also using a close proximity beacon 400 having a low energy Bluetooth transceiver, proceeds even closer to the plant 700 and enters the close proximity zone 820, this will be detected by one of the close proximity beacon receivers 200 and an alert or warning will be issued to display unit 100 in the plant 700 and the close proximity beacon 400 in the form of a flashing light or vibration, for example. It will be appreciated that the proximity of the close proximity beacon 400 and the GNSS proximity device 500, when both are fitted with Bluetooth transceivers, can be detected using Received Signal Strength Indication (RSSI).
[0070] In some embodiments, the movements of personnel 1 1 and the events or alerts triggered by personnel being detected in proximity to the plant can be logged and stored in a computer readable storage medium connected to the system.
[0071 ] According to another aspect, embodiments of the present invention relate to methods of detecting plant and personnel and assisting plant operators and personnel in proximity to maintain a safe distance between each other. With reference to FIG. 3, the method 900 comprises the step 905 of securing at least one plant proximity detector 200 to plant 700, wherein each plant proximity detector 200 has at least one wireless transceiver and a position sensor and each plant proximity detector is in communication with the display unit 100.
[0072] At 910, the method 900 comprises providing personnel proximity detectors 400, 500 to personnel, wherein each personnel proximity detector has one or more wireless transceiver in communication with the wireless transceiver of each plant proximity detector 200. The wireless transceiver of the personnel proximity detector 400, 500 can have a position sensor and the personnel proximity detector is in communication with the display unit 100.
[0073] At 915, the method 900 comprises configuring a detection zone around each plant proximity detector 200 via the position sensor of the plant proximity detector.
[0074] At 920, the method 900 comprises issuing an alert to at least one of the plant proximity detector 200, the personnel proximity detector 400, 500 and the display unit 100 when the personnel proximity detector 400, 500 is detected in the detection zone of the plant proximity detector 200.
[0075] The method can comprise coupling a plurality of plant proximity detectors 200 to fixed or mobile plant 700 and networking the plurality of plant proximity detectors 200, in particular over a controller area network (CAN) bus network 630.
[0076] The method can comprise defining a plurality of detection zones about the fixed or mobile plant 700 via the plurality of plant proximity detectors 200.
[0077] The method can comprise tuning the plant proximity detectors 200 to define an area or region covered by each detection zone.
[0078] The method can comprise at least one of the display unit 100, the plant proximity detector 200 and the personnel proximity detector 400, 500 issuing an alert if the personnel proximity detector 400, 500 is detected within one or more of the plurality of detection zones.
[0079] The method can comprise relaying a signal to every personnel proximity detector 400, 500 within range and/or every plant proximity detector 200 within range when any one of a plurality of the personnel proximity detectors 400, 500 associated with a plurality of personnel is detected within a detection zone.
[0080] The method can comprise activating an alert indicator 710 in communication with the display unit 100 when one of the plant proximity detectors 200 detects one of the personnel proximity detectors 400, 500 within a detection zone of the at least one plant proximity detectors 200.
[0081 ] The method can comprise communicating position information determined by one or more of the Global Navigation Satellite System (GNSS) sensors between the display unit 100 and the one or more personnel proximity detectors 400, 500 via the radio frequency transceivers.
[0082] The method can comprise indicating one or more conditions or states of at least one of the personnel proximity detectors 400, 500 via one or more visual indicators, or one or more feedback indicators for providing audio or haptic stimulation.
[0083] The method can comprise logging events and/or tracking personnel and/or plant on a computer readable storage medium in communication with the display unit 100.
[0084] Advantageously, the systems and methods allow personnel to be detected in a variety of locations around a worksite.
[0085] Further advantageously, the systems and methods provide warnings to machine operators and personnel to minimise the risk of accidents, injuries and death on a worksite.
[0086] Another particular advantage of some embodiments is that personnel on a worksite can be tracked relative to the location of the plant.
[0087] Further advantageously, it has been found that, using Bluetooth low energy (BLE) technology, proximity of personnel to plant can be detected despite obstacles even if GNSS signals are weak or unavailable.
[0088] Another advantage is that multiple detection zones can be defined for issuing differing levels of warnings and/or alerts based on the proximity of the personnel to a high risk area.
[0089] In some embodiments, it has been found that utilising multiple sensing technologies, i.e. BLE and GNSS provides greater operating range and protection against redundancy. For example, BLE signals can be used at short ranges, in particular for the detection of personnel in proximity to plant, where GNSS signals may be inaccurate or unavailable, and GNSS signals can be used at longer ranges, in particular for the detection of plant and personnel, where GNSS signals are more likely to be available and less susceptible to inaccuracies, such as multipathing.
[0090] A further particular advantage is that the systems and methods provide a 360° view of vehicles and personnel on a worksite.
[0091 ] In this specification, adjectives such as first and second, left and right, top and bottom, and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Where the context permits, reference to an integer or a component or step (or the like) is not to be interpreted as being limited to only one of that integer, components, or step, but rather could be one or more of that integer, components, or step, etc.
[0092] Further, in this specification, the terms 'comprises', 'comprising', 'includes', 'including', or similar terms are intended to mean a non-exclusive inclusion, such that a method, system, or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed.
[0093] The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art.
[0094] The invention is intended to embrace all alternatives, modifications, and variations of the present invention that have been discussed herein, and other embodiments that fall within the spirit and scope of the above described invention.