Method and device for checking screw connections, in particular wheel nuts, on a vehicle

Abstract

A device (6) for checking screw elements (8), in particular wheel nuts (8) of a wheel (4), on a vehicle (2) comprises: at least one camera (10) which is provided and designed for capturing at least one image of the vehicle (2) in such a way that the screw elements (8) to be checked are contained in the captured image; and an evaluation device (14). The evaluation device (14) is provided and designed for identifying the screw elements (8) to be checked in the at least one captured image; determining the orientation of the screw elements (8) to be checked in the at least one captured image; comparing the thus determined orientation of the screw elements (8) to be checked with a specified orientation of the screw elements (8) to be checked; and outputting a fault message if the previously determined orientation of at least one of the screw elements (8) to be checked deviates from the specified orientation of the respective screw element (8) by more than a specified tolerance.

Description

[0001] Description

[0002] title

[0003] Procedures and to check especially wheel nuts, on a

[0004] The invention relates to a method and a device for checking screw connections, in particular wheel nuts, on a vehicle.

[0005] State of the art

[0006] Especially for commercial vehicles, it is mandatory to check that the wheel nuts on the vehicle's wheels are tight before starting the journey.

[0007] For automated vehicles, too, daily departure checks and additional condition monitoring will remain in place or even be increased in scope, both from a legal perspective and in the operator's own interest.

[0008] Vehicles may also have other screw connections visible from the outside that need to be checked regularly.

[0009] Until now, these checks have been carried out manually or visually by a person, e.g. the driver of the vehicle, who walks around the vehicle before starting the journey and checks the screw connections / wheel nuts.

[0010] It is an object of the invention to simplify and accelerate the inspection of screw connections on vehicles, in particular the inspection of wheel nuts on the wheels of vehicles, and to improve the reliability of the inspection. The invention comprises a mechanical method for checking the alignment of screw elements, in particular wheel nuts of a wheel, on a vehicle. A method according to the invention comprises: recording at least one image of the vehicle with a camera such that the screw elements to be checked are included in the recorded image; mechanically identifying the screw elements to be checked in the at least one recorded image; mechanically determining the alignment of the screw elements to be checked in the at least one recorded image; mechanically comparing the thus determined alignment of the screw elements to be checked with a predetermined alignment of the screw elements to be checked; and issuing an error message if the previously determined alignment of at least one of the screw elements to be checked deviates from the predetermined alignment of the respective screw element by more than a predetermined tolerance.

[0011] The invention also encompasses a device for checking the alignment of screw elements, in particular wheel nuts of a wheel, on a vehicle. A device according to the invention comprises at least one camera and an evaluation device. The at least one camera is provided and configured to capture at least one image of the vehicle such that the screw elements to be checked are included in the captured image.The evaluation device is provided and designed to identify the screw elements to be checked in the at least one recorded image; to determine the orientation of the screw elements to be checked in the at least one recorded image; to compare the thus determined orientation of the screw elements to be checked with a predetermined orientation of the screw elements to be checked; and to output an error message if the previously determined orientation of at least one of the screw elements to be checked deviates by more than a predetermined tolerance from the predetermined orientation of the respective screw element.

[0012] With a method and a device according to the invention, the inspection of screw connections on a vehicle, in particular the inspection of the wheel nuts on the wheels of a vehicle, can be carried out quickly, reliably, and conveniently. The reliability of the inspection can also be improved because human errors, such as those that can occur during a human inspection of the screw connections, can be prevented.

[0013] The specified alignment of the bolt elements, with which the current alignment of the bolt elements is compared, may be the result of a previous check. In particular, the specified alignment of the bolt elements may be the result of an initial reference measurement taken after the bolt elements have been brought to their ideal state; for example, immediately after the wheels have been mounted on the vehicle.

[0014] In one embodiment, the method according to the invention is carried out on a stationary vehicle.

[0015] In one embodiment, the method according to the invention is carried out while the vehicle to be inspected passes the at least one camera. In this way, the method can be carried out particularly quickly, for example, within a few seconds. In particular, the method can be carried out without delaying the vehicle's departure.

[0016] In one embodiment, a device according to the invention comprises at least two cameras. This makes it possible to simultaneously inspect screw elements, in particular wheel nuts, located on both sides of the vehicle during a single pass between the at least two cameras. The process can thus be further accelerated.

[0017] In an alternative embodiment, two devices according to the invention can be used to check the screw elements, each of the two devices having a camera and one device being placed on each of the two sides of the vehicle. In one embodiment, determining the orientation of the screw elements to be checked comprises determining the relative orientation of at least two adjacent screw elements to one another and comparing this with a predetermined relative orientation of adjacent screw elements. By determining and comparing the orientations of adjacent screw elements, the orientation of the screw elements can be checked particularly easily and reliably.

[0018] In one embodiment, indicator elements, for example, wheel nut indicators, are mounted on the bolt elements. In this case, determining the orientation of the bolt elements to be checked involves determining the orientation of the indicator element mounted on the respective bolt element. The orientation of indicator elements can be detected and determined particularly easily and reliably by machine, since indicator elements are specifically designed for this purpose.

[0019] In one embodiment, the method further comprises detecting the absence of screw elements in the at least one recorded image and issuing an error message if the absence of at least one screw element has been detected. By detecting missing screw elements, the safety of a vehicle can be further increased using a method according to the invention.

[0020] In one embodiment, the method comprises illuminating the screw elements to be inspected in order to improve the quality of the at least one recorded image. In one embodiment, a device according to the invention accordingly comprises at least one illumination device configured to illuminate the screw elements to be inspected. The illumination device may contain at least one LED.

[0021] In images taken of well-lit screw elements, the alignment of the screw elements can be detected particularly well and reliably by machine. The quality and reliability of a method according to the invention can be further improved in this way.

[0022] In one embodiment, the method comprises storing the at least one recorded image of the screw elements for documentation purposes. For this purpose, a device according to the invention can be equipped with a storage device in which the recorded images can be stored and retrieved at a later time if necessary.

[0023] By storing and machine-analyzing images taken at different times, gradual changes in the alignment of the screw elements can be detected particularly well.

[0024] Alternatively or additionally, the recorded images can be stored outside the device according to the invention, for example in a central server or in a virtual cloud.

[0025] In one embodiment, the device according to the invention is designed to output the error message to a higher-level entity, for example, a central system, which further processes this information. The higher-level entity can, for example, be designed to inform the driver or vehicle operator, a test inspector, and / or another person about the detected error. The higher-level entity can also be designed to store information about the performance of the test and the result of the test in a fleet management system.

[0026] In one embodiment, the device itself comprises an output device that enables the device to output an error message.

[0027] The output device can be integrated into the evaluation device or into the camera. Alternatively, the output device can be designed separately from the evaluation device and / or the camera. The device can be equipped with an optical output device, for example, a display and / or a signal light, which enables the device to output a visual error message.

[0028] Alternatively or additionally, the device may be equipped with an acoustic output device, such as a loudspeaker, a buzzer, and / or a horn. This enables the device to emit an acoustic error message.

[0029] If no errors are detected, a visual and / or acoustic confirmation ("OK message") can be issued to indicate that the vehicle's screw elements have been checked and are OK.

[0030] An embodiment of the invention is described below with reference to the accompanying drawings.

[0031] Short description of the characters

[0032] Figure 1 shows a schematic plan view of a vehicle on which a device according to the invention for checking screw elements of the vehicle is positioned.

[0033] Figure 2 shows a schematic side view of a device according to the invention for checking screw elements on a vehicle.

[0034] Figure 3 shows an example of an indicator element designed as a wheel nut indicator that can be attached to a wheel nut.

[0035] Figure 4 shows a wheel with a plurality of wheel nuts on which wheel nut indicators are mounted.

[0036] Figure 5 shows an enlarged section of Figure 4, showing two adjacent wheel nuts that are correctly aligned. Figure 6 shows an enlarged section of Figure 4, showing two adjacent wheel nuts that are not correctly aligned.

[0037] Figure 1 shows a schematic view of a vehicle 2, in particular a motor vehicle 2 with four wheels 4. On one of the wheels 4, a device 6 according to the invention for checking the wheel nuts 8 (screw elements) of the wheel 4 is positioned

[0038] Vehicle 2 can be, for example, a car, a truck, or a bus. Vehicle 2 can also be a trailer (not shown in the figures). Vehicle 2 can also be a rail-bound vehicle or an aircraft.

[0039] Figure 2 shows a schematic view of a device 6 according to the invention for checking screw elements 8, in particular wheel nuts 8, together with a wheel 4 whose wheel nuts 8 are to be checked.

[0040] The device 6 comprises at least one image recording device or camera 10. The camera 10 is provided and designed to record at least one image of the wheel 4 such that the wheel nuts 8 of the wheel 4 to be checked are included in the image recorded by the camera 10.

[0041] The at least one camera 10 can be mounted on a tripod or column 12, as shown by way of example in Figure 2. Alternatively, the camera 10 can also be mounted on a ceiling or on a wall of a measuring station or vehicle hall, which are not shown in the figures. Alternatively, the camera 10 can also be the camera 10 of a mobile device, for example, a smartphone.

[0042] Optionally, the device 6 can additionally comprise an illumination device 15, which is provided and configured to illuminate the wheel 4 with the wheel nuts 8 to be inspected. The device 6 also comprises an evaluation device 14, which is provided and configured to identify the wheel nuts 8 to be inspected in the at least one recorded image and to determine the orientation of the wheel nuts 8 to be inspected in the at least one recorded image.

[0043] This can be done using known methods of automatic image recognition and / or artificial intelligence methods.

[0044] The evaluation device 14 is further provided and designed to compare the thus determined alignment of the wheel nuts 8 to be checked with a predetermined alignment of the wheel nuts 8 to be checked and to output an error message if the previously determined alignment of the wheel nuts 8 to be checked deviates from the predetermined alignment by more than a predetermined tolerance.

[0045] This can also be done using known methods of automatic image recognition and / or artificial intelligence methods.

[0046] The evaluation device 14 can, for example, be configured to output the error message to a central system 16, which further processes the error message. The central system 16 can, for example, be configured to inform the driver or operator of the motor vehicle 2, a test inspector, and / or another responsible person about the detected error.

[0047] The device 6 according to the invention and / or the central system 16 can each be equipped with a storage device 24, 26 in which the recorded images can be stored and retrieved at a later time if necessary.

[0048] The error message can be transmitted to the central system 16 either wired or wirelessly, for example, via a WLAN data connection or a Bluetooth® data connection. The evaluation device 14 and the central system 16 can each be equipped with a corresponding transmitting and receiving device 17 for this purpose.

[0049] Alternatively or additionally, an output device 18 can be provided on the device 6 according to the invention itself, which output device is intended and designed to output an error message.

[0050] The output device 18 can be integrated into the evaluation device 14 or into the camera 10. Alternatively, the output device 18 can be formed separately from the evaluation device 14 and / or the camera 10.

[0051] The output device 18 may comprise an optical output device 18a, for example a display and / or a signal light, which is provided and designed to output an optical error message.

[0052] Alternatively or additionally, the output device 18 may comprise an acoustic output device 18b, for example a loudspeaker, a buzzer and / or a horn, wherein the acoustic output device 18b is provided and designed to output an acoustic error message, for example a warning tone and / or an acoustic announcement.

[0053] In one embodiment of the invention, indicator elements 20, also referred to as wheel nut indicators, can be mounted on the wheel nuts 8.

[0054] Figure 3 shows an example of a wheel nut indicator 20 that can be mounted on a wheel nut 8. The wheel nut indicator 20 has, in particular, a lug 22 that makes it easier to determine the spatial orientation of the wheel nut indicator 20 and thus also the orientation of the wheel nut 8 on which the wheel nut indicator 20 is mounted.

[0055] The design of the indicator element / wheel nut indicator 20 shown in Figure 3 is only an example. Indicator elements / wheel nut indicators 20 with other designs can also be used. Figure 4 shows, by way of example, a wheel 4 of a motor vehicle 2 with a plurality of wheel nuts 8 on which indicator elements / wheel nut indicators 20, as shown in Figure 3, are mounted.

[0056] Figures 5 and 6 each show an enlarged section of Figure 4, in which two adjacent wheel nuts 8, on each of which an indicator element 20 is mounted, can be seen.

[0057] In Figure 5, the lugs 22 of the two indicator elements 20 are aligned along a common line so that they point toward each other. This indicates that the two wheel nuts 8 are correctly aligned and fully tightened.

[0058] In Figure 6, the lugs 22 of the two indicator elements 20 are not aligned along a common line. In particular, the wheel nut 8 shown on the left is rotated approximately 45° counterclockwise compared to the orientation shown in Figure 5. The indicator element 20 shown on the left, and thus also the left wheel nut 8 to which the indicator element 20 is attached, therefore no longer has the specified alignment. This indicates that the left wheel nut 8 has come loose.

[0059] If the evaluation device 14 detects an alignment of a wheel nut 8 or an indicator element 20, as shown by way of example in Figure 6, the evaluation device 14 outputs an error message indicating that at least one wheel nut 8 on the wheel 4 being checked is not in the intended position but has presumably come loose.

[0060] The orientations of the indicator elements 20 shown in Figures 5 and 6 are particularly easy to identify using automatic image recognition methods. It is therefore possible to reliably determine whether the indicator elements 20, and thus also the wheel nuts 8 on which the indicator elements 20 are mounted, are in the intended orientation.

[0061] Alternatively, it is also possible to detect the alignment of wheel nuts 8 without indicator elements 20 due to the geometric shape of the wheel nuts 8, which are usually designed as hexagon nuts. If no indicator elements 20 are present on the wheel nuts 8, it is possible that a wheel nut 8 has accidentally rotated so far around its own axis between two inspections that it has come loose, but the change is not visually detectable due to the symmetry of the wheel nut 8, since its current alignment coincides with the previous reference image.

[0062] When a method according to the invention is regularly performed and a wheel nut 8 gradually becomes loose, this is statistically possible, but very unlikely. Therefore, even in this case, it can be assumed that a loosening wheel nut 8 will be reliably detected before it completely loosens.

[0063] The detection according to the invention is more reliable the lower the rotational symmetry of the wheel nut 8 or the screw element 8 is.

Claims

1. A method for the mechanical inspection of screw elements (8), in particular wheel nuts (8), on a vehicle (2), the method comprising: recording at least one image of the vehicle (2) with a camera (10) such that the screw elements (8) to be inspected are included in the recorded image; mechanically identifying the screw elements (8) to be inspected in the at least one recorded image; mechanically determining the orientation of the screw elements (8) to be inspected in the at least one recorded image; mechanically comparing the thus determined orientation of the screw elements (8) to be inspected with a predetermined orientation of the screw elements (8) to be inspected; and outputting an error message if the previously determined orientation of at least one of the screw elements (8) to be inspected deviates from the predetermined orientation of the respective screw element (8) by more than a predetermined tolerance.

2. Method according to claim 1, wherein the mechanical determination of the orientation of the screw elements (8) to be checked comprises determining the relative orientation of adjacent screw elements (8) to one another and comparing it with a predetermined relative orientation of adjacent screw elements (8).

3. Method according to one of the preceding claims, wherein indicator elements (20) are mounted on the screw elements (8), and wherein the mechanical determination of the orientation of the screw elements (8) to be checked comprises mechanically determining the orientation of the indicator element (20) mounted on the respective screw element (8).

4. The method according to any one of the preceding claims, wherein the method comprises taking the at least one image of the vehicle (2) while the vehicle (2) passes the at least one camera (10).

5. Method according to one of the preceding claims, wherein the method comprises mechanically detecting the absence of screw elements (8) and issuing an error message when the absence of at least one screw element (8) has been detected.

6. Method according to one of the preceding claims, wherein the method comprises illuminating the screw elements (8) to be checked.

7. The method according to any one of the preceding claims, wherein the method comprises storing the at least one captured image for documentation purposes.

8. Device (6) for checking screw elements (8), in particular wheel nuts (8), on a vehicle (2), the device comprising: at least one camera (10) which is provided and designed to record at least one image of the vehicle (2) such that the screw elements (8) to be checked are included in the recorded image; and an evaluation device (14) which is provided and designed to: identify the screw elements (8) to be checked in the at least one recorded image; to determine the orientation of the screw elements (8) to be checked in the at least one recorded image; to compare the orientation of the screw elements (8) to be checked thus determined with a predetermined orientation of the screw elements (8) to be checked; and to output an error message if the previously determined orientation of at least one of the screw elements (8) to be checked deviates from the predetermined orientation of the respective screw element (8) by more than a predetermined tolerance.

9. Device according to claim 8, with an optical output device (18a) provided and designed to output an optical error message; and / or with an acoustic output device (18b) provided and designed to output an acoustic error message.

10. Device according to claim 8 or 9, wherein the evaluation device (14) is provided and designed to determine the relative orientation of adjacent screw elements (8) to one another and to compare them with a predetermined relative orientation.

11. Device according to one of claims 8 to 10, wherein the evaluation device (14) is provided and designed to identify indicator elements (20) mounted on the screw elements (8) and to determine the orientation of the indicator elements (20) mounted on the screw elements (8).

12. Device according to one of claims 8 to 11, wherein the device comprises a lighting device (15) which is provided and designed to illuminate the screw elements (8).

13. Device according to one of claims 8 to 12, wherein the at least one camera (10) is provided and designed to record the at least one image of the vehicle (2) while the vehicle (2) drives past the at least one camera (10).

14. Device according to one of claims 8 to 13, wherein the evaluation device (14) is provided and designed to detect the absence of screw elements (8) and to output an error message when the absence of at least one screw element (8) has been detected.

15. Device according to one of claims 8 to 14, wherein the device comprises a storage device (24) which is provided and designed to store the at least one recorded image.

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