Lifting System for Lifting a Vehicle with Indirect Height Measurement and Method Therefor

Abstract

A lifting system for lifting a vehicle, including a mobile frame with a moveable carrier configured for carrying the vehicle; a drive which acts on the carrier and has a hydraulic system; a measurement system including a sensor configured for indirect measurement of the height of the carrier, with the sensor configured for generating an indirect measurement signal from the hydraulic system that is indicative for the height of the carrier, or a change thereof; and a controller configured for controlling the height of the carrier in response to the indirect measurement signal of the measurement system.

Claims

1.-14. (canceled)

15. A lifting system for lifting a vehicle, the system comprising: a mobile frame with a moveable carrier configured for carrying the vehicle; a drive which acts on the carrier and comprises a hydraulic system; a measurement system comprising a sensor configured for indirect measurement of the height of the carrier, with the sensor configured for generating an indirect measurement signal from the hydraulic system that is indicative for the height of the carrier, or a change thereof; and a controller configured for controlling the height of the carrier in response to the indirect measurement signal of the measurement system.

16. The lifting system according to claim 15, wherein the drive acting on the carrier comprises a hydraulic liquid reservoir and hydraulic connections, and wherein the sensor of the measurement system is contained in the hydraulic reservoir and/or in the hydraulic connections and is configured for measuring the level, pressure, or volume of hydraulic liquid and/or the change thereof.

17. The lifting system according to claim 16, wherein the sensor of the measurement system comprises one or more of the following sensors: an ultrasonic hydraulic liquid level sensor, a float sensor configured for measuring the hydraulic liquid level, a pressure sensor configured for measuring pressure and/or pressure differences in the reservoir, and a weight measurement of the hydraulic liquid that is contained in the reservoir.

18. The lifting system according to claim 17, wherein the float sensor comprises an electromagnetic float and/or resistance element and/or an inclinometer.

19. The lifting system according to claim 15, wherein the sensor of the measurement system comprises a flow sensor configured for measuring the flow of hydraulic liquid to and/or from the drive.

20. The lifting system according to claim 15, wherein the measurement system further comprises a temperature sensor enabling a temperature compensation of the indirect measurement.

21. The lifting system according to claim 16, wherein the drive comprises a pump that is submerged in the reservoir.

22. The lifting system according to claim 15, wherein the lifting system comprises a group of lifting columns.

23. The lifting system according to claim 16, wherein the lifting system comprises a group of lifting columns.

24. The lifting system according to claim 21, wherein the lifting system comprises a group of lifting columns.

25. A method for controlling a lifting system for lifting a vehicle, the method comprising: providing a lifting system comprising: a mobile frame with a moveable carrier configured for carrying the vehicle; a drive which acts on the carrier and comprises a hydraulic system; a measurement system comprising a sensor configured for indirect measurement of the height of the carrier, with the sensor configured for generating an indirect measurement signal from the hydraulic system that is indicative for the height of the carrier or the change thereof; and a controller configured for controlling the height of the carrier in response to the indirect measurement signal of the measurement system; lifting the vehicle with the drive acting on the carrier; indirectly measuring the height of the carrier and providing the controller with the indirect measurement signal from the hydraulic system; and in response to the indirect measurement signal received by the controller determining the presence of height differences and providing one or more control signals to correct a determined height difference of the carrier.

26. The method according to claim 25, wherein indirectly measuring comprises measuring a hydraulic liquid level or volume and/or a change thereof.

27. The method according to claim 25, wherein indirectly measuring comprises measuring a hydraulic pressure and/or a change thereof.

28. The method according to claim 25, wherein indirectly measuring comprises measuring a hydraulic liquid flow to and/or from the drive.

29. The method of claim 25, further comprising comparing the measurement with theoretical changes of the hydraulic system to enable detection of leakage and/or wear of components.

30. The method of claim 29, comprising comparing the step of comparing with a motor RPM.

31. The method of claim 25, further comprising synchronizing lifting columns of the lifting system during a lifting operation, the synchronizing including moving speed of the carrier.

32. The method of claim 31, wherein the lifting system comprises two or more lifting columns.

33. A lifting system for lifting a vehicle, the system comprises: a mobile frame with a moveable carrier configured for carrying the vehicle; a drive which acts on the carrier and comprises a hydraulic system; a measurement system comprising a sensor configured for indirect measurement of the height of the carrier, with the sensor configured for generating an indirect measurement signal indicative for a height of the carrier or change thereof, wherein the sensor of the measurement system is configured to measure a force generated by a spring element with one end connected to the carrier and with another end connected to a reference point.

34. A lifting system for lifting a vehicle, the system comprising: a mobile frame with a moveable carrier configured for carrying the vehicle; a drive which acts on the carrier and comprises a hydraulic system; a measurement system comprising a sensor configured for indirect measurement of the height of the carrier, with the sensor configured for generating an indirect measurement signal indicative for a height of the carrier or change thereof, wherein the sensor of the measurement system is configured for measuring an angle between the carrier and the frame and/or the change thereof.

Description

[0049] Exemplary embodiments of a lifting system and/or the method according to the present invention are described here below on the basis of a non-limitative exemplary embodiment therefor shown in the accompanying drawings, wherein:

[0050] FIG. 1 shows a schematic overview of a vehicle lifted by lifting columns for a lifting system according to the invention;

[0051] FIG. 2 shows a schematic overview of the hydraulic scheme of the drive of FIG. 1 including components of the measurement system; and

[0052] FIG. 3 shows alternative measurement systems.

[0053] System 2 for efficient lifting and lowering load 6 (FIG. 1) comprises four wireless mobile lifting columns 4. Lifting columns 4 lift passenger car 6 from ground 8. In the illustrated embodiment lifting columns 4 are connected to each other and/or a control system by wireless communication means or alternatively by cables. Lifting columns 4 comprise foot 10 which can travel on running wheels 12 over ground surface 8 of for instance a floor of a garage or workshop. In the forks of foot 10 is provided an additional running wheel (not shown). Lifting column 4 furthermore comprises mast 14. Carrier 16 is moveable upward and downward along mast 14. Carrier 16 is driven by motor 18 of the drive of the lifting column that is provided in a housing of lifting column 4. Motor 18 is supplied with power from the electrical grid or by a battery that is provided on lifting column 4 in the same housing as motor 18, or alternatively on foot 10 (not shown). Control with control panel 20 is provided to allow the user of system 2 to control the system, for example by setting the speed for carrier 16. In one embodiment, motor 18 is a 3-phase low voltage motor controlled by a separate controller. In another embodiment, motor 18 is a 3-phase low voltage motor with integrated controller. Such motor with integrated controller can also be used in combination with conventional lifting devices with conventional height measurement systems.

[0054] Each of the lifting columns has at least one ascent mode and one descent mode, and is under the influence of control 20. Control 20 can be designed for each lifting column 4 individually, or for the lifting columns 4 together. A pressure or load sensor may be used for monitoring, control and indication of the load that is lifted with lifting system 2.

[0055] Measurement system 22 provides an indirect measurement of the carrier height D. In the illustrated embodiment measurement system 22 is included in hydraulic circuit 24 (FIG. 2). In the illustrated embodiment hydraulic circuit 24 is operatively connected to hydraulic cylinder 26 with piston 28 that drives carrier 16. Motor 18 provides cylinder 26 with hydraulic liquid, such as oil, from reservoir 30 by activating pump 32. Pump 32 is connected to reservoir 30 with suction pipe 34. Valve block 36 directs hydraulic liquid from reservoir pump 32 towards supply pipe 38 through valve 40. Liquid is directed through valve 42 towards hydraulic cylinder 26. Recirculation pipe 44 with valve 46 enables recirculation of hydraulic liquid in a reservoir 30.

[0056] It will be understood that alternative embodiments of hydraulic circuit 24 can be envisaged in accordance with the present invention.

[0057] In the illustrated embodiment hydraulic liquid 48 is contained in reservoir 30. Above hydraulic liquid 48 there is provided room or chamber 50.

[0058] In one of the embodiments of the invention ultrasonic sensor 52 is provided in room 50 capable of measuring distance d between sensor 52 and hydraulic liquid 48 with ultrasonic signal 54. Alternatively, or in addition thereto, float 56 can be used to measure the hydraulic liquid level directly. Furthermore, in addition or as an alternative to the aforementioned sensor(s), flow sensor 58 can be provided in hydraulic circuit 24, for example in suction pipe 34. It will be understood that other locations for flow sensor 58 can also be envisaged in accordance with the present invention.

[0059] Controller 60 receives measurement signals 62, 64, 66 from sensors 52, 56, 58. Controller 60 determines the height of carrier 16. Preferably, controller 60 is a central controller configured for controlling the lifting columns, optionally communicating with (local) controllers of lifting devices. Controller 60 and/or the local controllers determine the height and/or speed differences between individual carriers 16 and determine required control actions. These control actions may result in sending control signal 68 to motor 18 and/or other control signals 70.

[0060] In the illustrated embodiment control signal 70 is provided to valve controller 72 that directs appropriate control signals 74 to individual valves 40, 42, 46 of valve block 36. It will be understood that other configurations for the controller can be envisaged in accordance to the present invention.

[0061] Alternative measurement system 76 can be applied in combination with or as an alternative to measurement system 22 that is illustrated in FIG. 1. Measurement system 76 (FIG. 3) comprises a first sub-system 78 and a second sub-system 80 that can be used in combination, as an alternative, and/or in combination with measurement system 22, or as an alternative therefor. Measurement system 78 comprises a transceiver 82. In the illustrated embodiment transceiver 82 is attached to foot 10. A second transceiver 84 is attached to carrier 16. When moving carrier 16, signal 86 changes its direction between transceivers 82, 84, or more specifically changes its angle relative to the vertical as determined by mast 14. This angle provides a measurement for the actual height of carrier 16.

[0062] Measurement system 80 comprises height element 88 that is connected at connection 90 to carrier 16 and with measuring unit 92 to foot 10. The force measured by sensor 92 is a measurement for the height of carrier 16. In the illustrated embodiment element 88 is a spring element.

[0063] The present invention can be applied to the (wireless) lifting columns illustrated in FIG. 1. Alternatively the invention can also be applied to other types of lifting columns and lifting systems.

[0064] The present invention is by no means limited to the above described preferred embodiments. The rights sought are defined by the following claims within the scope of which many modifications can be envisaged. It will be understood that instead of the ultrasonic sensor other types of sensors can be applied similarly in accordance with the present invention. This may involve optical sensors, or sensors making use of other signal types operating in a similar manner as described in relation to the ultrasonic sensor 20.