Abstract:
The present invention relates to a lifting system and method for lifting a vehicle, wherein the lifting system including one or more lifting devices and: a frame with a carrier configured for carrying the vehicle; a drive for driving the carrier in at least one of the ascent or descent of the carrier; and a controller including an indoor positioning system with a transponder, wherein the transponder is provided on or at the carrier such that the controller determines the location and the height of the carrier in at least one of the ascent or descent of the carrier.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to Netherlands Patent Application No. 2015532 filed Sep. 30, 2015, the disclosure of which is hereby incorporated in its entirety by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The invention relates to a lifting system, more specifically a vehicle lifting system. In general, lifting systems are specifically used for lifting passenger cars, trucks, busses, or other vehicles and may involve a system comprising one or more moveable lifts or lifting devices, such as (mobile) lifting columns, lifting columns of the two-post lift type with pivoting support arms, the four-post lift type with runways, the mobile type, in-ground lifts etc. 
         [0004]    Description of Related Art 
         [0005]    Conventional lifting systems comprise a frame with a carrier that is connected to a drive for moving the carrier upwards and downwards. In the ascent mode, hydraulic oil is pumped to a cylinder for lifting the carrier and, therefore, the vehicle. In the descent mode, the carrier with the vehicle is lowered and hydraulic oil returns to the reservoir. Such prior art lifting system is disclosed in U.S. Patent Application Publication No. 2006/0182563, which is incorporated herein by reference. Such lifting systems as well as other lifting systems require the use of a number of sensors, such as height sensors, to enable correct operation of the lifting system. This involves integration of these sensors and related components into the control system. 
         [0006]    An object of the invention is to reduce complexity of vehicle lifting systems and/or to improve safety when working with these vehicle lifting systems. 
       SUMMARY OF THE INVENTION 
       [0007]    This object is achieved with a lifting system for lifting a vehicle according to the invention, the lifting system comprising:
       a frame with a carrier configured for carrying the vehicle;   a drive for driving the carrier in at least one of the ascent or descent of the carrier; and   a controller comprising an indoor positioning system with a transponder, wherein the transponder is provided on or at the carrier such that the controller determines the location and the height of the carrier in at least one of the ascent or descent of the carrier.       
 
         [0011]    The lifting system according to the invention specifically relates to a vehicle lifting system using a number of lifting devices, including lifting columns, mobile lifting columns, lifting columns of the two-post lift type with pivoting support arms, the four-posts lift type with runways, in-ground lifts, for example. In the context of the present invention the carrier relates to the moving parts of the lifting device when lifting the vehicle. This carrier is driven by a drive, such as a hydraulic drive, pneumatic drive and/or electric drive. 
         [0012]    The lifting system according to the present invention comprises a controller with an indoor positioning system. Such indoor positioning system is capable of communicating with one or more transponders, also referred to as transmitter and responder. The transponder transmits a message in response to a received message. The indoor positioning system is capable of locating the lifting device, and more specifically the carrier of the lifting device, inside a building, using radio waves, magnetic fields, acoustic signals or other means of transferring information. Possibly, a combination of signals can be applied. With the use of optical, radio or acoustic technologies, or other convenient technologies, the position and height of the carrier can be determined. Preferably, at least three independent measurements are used by the control system to determine the location and height of the carrier involving the use of trilateration. 
         [0013]    The transponders may relate to so-called active transponders that are provided with an energy supply such as a battery or power supply. Also, transponders may relate to so-called passive transponders that receive the required energy from the received signal. An indoor positioning system using wi-fi signals is also referred to as a wi-fi-based positioning system. Also, blue tooth and other signals can be used in addition or as an alternative. Alternatively, or in combination with the aforementioned active and/or passive transponders, other devices acting as transponder can be applied. In the context of the present invention a transponder is a device that is capable of generating or forwarding a signal indicative for its location (and height), preferably in response to an interrogating (received) signal. 
         [0014]    By providing the transponder on or at the carrier, both location and height of the carrier can be determined with the indoor positioning system of the controller. This obviates the need for separate height sensors, as the transponder can be used for both location determination and for height measurement of the carrier during the lifting operation. This renders the lifting system less complex. Location of lifting devices is used when selecting lifting devices for a lifting system. This specifically relates to mobile lifting column, for example. The height measurement is relevant for all types of lifting devices. 
         [0015]    As an example, in an embodiment of a lifting system according to the invention, at least two lifting columns are being used as lifting devices. In fact, often four lifting columns are being used. When lifting a vehicle, controlling the actual height of the carriers of these separate lifting columns and optionally also the moving speed of the carrier that carries (part of) the vehicle when lifting a vehicle requires synchronization. The controller preferably synchronizes the height of the separate carriers in the ascent mode using, for example, a measurement signal generated by the indoor positioning system. In case one of the carriers has moved too fast in the ascent mode and is too high as compared to the other carriers of the other lifting columns the power supply to this carrier is either directly or indirectly lowered so that the other carriers can catch up or, alternatively, the power supply to the other carriers is either directly or indirectly increased so that the other carriers can catch up. In the descent mode, it is also important that the height of the carriers between the several lifting columns is synchronized. Therefore, in case one of these carriers has moved too slowly, its power supply is increased in order for this carrier to catch up with the other carriers or, alternatively, the power supply to the other carriers is either directly or indirectly lowered so that the other carriers can catch up. 
         [0016]    Other types of lifting devices involve a similar (synchronization) operation and may also benefit from the use of the indoor positioning system. 
         [0017]    Preferably, the controller further comprises an orientation detector. With the orientation detector, the orientation of the lifting device can be established with the indoor positioning system. For example, the orientation of a lifting device is relevant when using mobile lifting columns that can be repositioned in a building relative to the vehicle to be lifted. In one of the embodiments according to the present invention, the orientation detector is a further transponder. Alternatively or in addition thereto, the orientation detector comprises an electronic compass or so-called magnetometer. An example of such magnetometer is known from consumer devices such as mobile phones and tablet computers. 
         [0018]    In a presently preferred embodiment according to the present invention the controller further comprises a monitoring system configured for monitoring a safety zone. 
         [0019]    By providing a monitoring system, the lifting system can be protected with a safety zone. This safety zone defines an area or zone that is monitored using one or more sensors, optionally including transponders. When a person and/or object enters the safety zone and/or is present in the safety zone, movement of the carrier is optionally blocked by the controller. This increases safety when working with the system according to the present invention. This safety zone preferably is a three-dimensional zone that can be shaped as a wall, circle, sphere, dome, or any other appropriate shape. The safety zone can be shaped with one or more boundaries. For example, in one embodiment the safety zone comprises an inner working zone and an outer non-working zone. In another embodiment the safety zone comprising an inner non-working zone, for example directly under the lifting device, an intermediate working zone, and an outer non-working zone. It will be understood that other examples of the shape and size of the safety zone can be envisaged. 
         [0020]    In a further preferred embodiment according to the present invention the monitoring system comprises an adaptation system that is configured for adjusting the boundaries of the safety zone. 
         [0021]    Preferably, the monitoring system comprises an adaptation system configured for adjusting the boundaries of the safety zone. In a presently preferred embodiment, the adaptation system responds to a height measurement of the carrier. The adaptation system may adjust the boundaries of the safety zone, rendering the safety zone dynamic in size and/or shape. Other parameters may also be used by adaptation system, such as the presence and/or type of vehicle that is lifted and the distance to other systems and other sets of lifting devices. Therefore, the lifting system may comprise a vehicle detector that is capable of detecting the presence of a vehicle and preferably the vehicle type. 
         [0022]    As an example, the adaptation system enables adjustment in response to the actual height of the carrier and/or the presence of a vehicle in the lifting system of the present invention. The safety zone may have a (dynamic) working/operational zone wherein an operator may perform operations with the lifting system. For example, in some cases, in a zone directly under and/or around the lifting system operating the lifting system with a remote control is prohibited. For example, in an in-ground lift the remote control is enabled to operate under the vehicle when the carrier is below a height of about 30 cm. This enables positioning the carriers, for example. This (safety) zone is (dynamically) established in response to a height measurement to prevent a person from getting under the vehicle when moving the carrier, for example. In a further example, the outer boundary of the safety zone defines the maximum distance from the lifting system an operator may use the lifting system. In one of the embodiments, this results in a dynamic safety zone with an inner boundary and an outer boundary. This safety zone can be shaped as a wall, block, three-dimensional shape, dome shape, and other appropriate shapes. 
         [0023]    In a further preferred embodiment according to the present invention, the monitoring system further comprises a warning system configured for providing a warning signal and/or control signal in response to a person and/or object provided with a transponder entering and/or being in the safety zone. 
         [0024]    By providing a warning system, appropriate warning and/or control signals can be generated. A warning signal can be provided to an operator, for example with a mobile device such as a phone or tablet computer. Also, a warning can be provided to a supervisor or other person or system. Alternatively or in addition thereto, a control signal can be provided to the controller and optionally the lifting system can be blocked until the person and/or object has been removed from the safety zone, for example. 
         [0025]    In a further preferred embodiment according to the present invention the monitoring system further comprises an engagement safety system configured for monitoring correct engagement of the carrier to the vehicle when lifting the vehicle. 
         [0026]    By providing an engagement safety system a correct engagement of the carrier to the vehicle, for example to the wheel axles, wheels or other engagement area of the vehicle can be monitored. In case of an incorrect engagement, the lifting system can be blocked by the controller. The engagement safety system may use a camera or other sensing device for monitoring the engagement. The transponder can be used by the controller to establishe that the carrier is indeed blocked in case of a warning. This increases the overall safety of the lifting system according to the present invention. 
         [0027]    Preferably, the monitoring system further also comprises a descent safety system configured for monitoring a safe descent of the carrier. This is for example advantageously applied to an in-ground lifting system of a fully flush-mounted type. The correct location can be determined by the controller using the transponder on the carrier of the indoor positioning system, for example. For example, such flush-mounted type in-ground lift is described in U.S. Pat. No. 8,523,146, which is incorporated herein by reference. Also, in a presently preferred embodiment of the present invention it is possible that the controller of the lifting system uses the transponders to position the carrier correctly in a descent mode. Correctly positioning the lifting device is optionally done automatically by the controller. 
         [0028]    In a further preferred embodiment according to the present invention, the lifting system further comprises a release system for releasing the carrier and enabling the lifting system to lift the vehicle. 
         [0029]    By providing a release system, the lifting system can be enabled to lift a vehicle. Preferably, the release system is controlled in cooperation with the monitoring system. Optionally, the release system is controlled by the controller in response to payment instructions, identification and/or authorization procedures. The release system may involve locking and/or unlocking means. This prevents undesired and/or unneeded lifts. In addition, this also enables direct debiting of the vehicle owner for the usage of the lifting system, providing a type of so-called pay-per-lift debiting system. Optionally, the release system receives a clearance signal of a clearance system after payment, identification and/or authorization to perform a number of lifting operations, optionally in a specific time period. 
         [0030]    In a further preferred embodiment according to the present invention, the controller further comprises a remote control. 
         [0031]    By providing a remote control, the operation of the lifting system is rendered more easy and effective for an operator. The remote control may relate to a mobile phone, tablet computer or other device. Preferably, the indoor positioning system also senses the location of the remote control and uses the information in the monitoring system, for example. This can be achieved by providing the remote control with a transponder of the indoor positioning system, for example. 
         [0032]    In a further preferred embodiment according to the present invention, the lifting system comprises two or more sets of lifting devices, wherein each set is configured for lifting a vehicle, the lifting system further comprising a central controller. 
         [0033]    By providing a central controller, the controller is capable of controlling multiple lifting systems and/or multiple sets of lifting devises. As an example, when a vehicle needs to be lifted, a set of (mobile) lifting columns is selected and is defined as a group. The central controller controls this group of lifting devices. Another group of lifting devices can also be controlled by the central controller independently. Optionally, the central controller instructs the adjustment system of the monitoring system to amend or adjust boundaries of the safety zone, taking into account the location of the different groups of lifting columns. Furthermore, the central controller may communicate with remote computers or computer systems for maintenance and repair, logistics, debiting etc. 
         [0034]    Optionally, the central controller selects a set of lifting devices that is available and most convenient for a user. Next, the user can be provided with a suggested set of lifting devices that he only needs to approve. This prevents the user to contact each individual lifting device that needs to be selected. Optionally, the selection is automatically authorized and the specific set of lifting devices is directly ready for use. 
         [0035]    In a further preferred embodiment according to the present invention, the lifting system further comprises one or more tools and/or accessories that comprise a transponder. 
         [0036]    By providing tools and/or accessories with a transponder, the indoor positioning system is capable of determining the location of these tools and/or accessories. This information can be used in the safety system, for example. Furthermore, this information can be used by the controller for monitoring location (and height) of tools, such us wheel dollies, axle stands, transmission jacks etc., relative to the vehicle. Optionally, the controller locks the lifting system until the required tools and/or accessories are available on the desired location, for example. 
         [0037]    As a further example, in case the remote control with transponders is below 460 mm or 18 inch from the work floor, the remote control can be blocked by the controller and it is no longer active in the lifting system. This contributes to an explosion-proof lifting system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0038]    Further advantages, features and details of the invention will be elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which: 
           [0039]      FIG. 1  shows a lifting system with multiple groups of lifting devices and a central controller according to the present invention; and 
           [0040]      FIGS. 2-6  show alternative embodiments with different types of lifting devices according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0041]    The following description is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. While the disclosure is described as having exemplary attributes and applications, the present disclosure can be further modified. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice of those skilled in the art to which this disclosure pertains and which fall within the limits of the appended claims. Accordingly, the following description of certain embodiments and examples should be considered merely exemplary and not in any way limiting. 
         [0042]    In the illustrated embodiment lifting system  2  ( FIG. 1 ) comprises two sets of mobile lifting columns  2   a ,  2   b . In the illustrated embodiment each set comprises four mobile lifting columns  4 . Lifting columns  4  lift passenger car  6  from ground  8 . 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  there is provided an additional running wheel (not shown). Lifting column  4  furthermore comprises mast  14 . Carrier  16  is moveable in upward and downward directions along mast  14 . Carrier  16  is driven by a motor  18  that is located 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). Display unit  20  may provide the user with information about the lifting system. 
         [0043]    In the illustrated embodiment lifting columns  4  are connected to central controller  22  by wireless communication means  24  on individual lifting column  4  and wireless communication means  26  on central controller  22 . Wireless communication means  24 ,  26  involve one or more transmitters and/or receivers. 
         [0044]    The illustrated lifting system  2  includes at least two lifting columns  4 . Each of the lifting columns has at least one ascent mode and one descent mode, and is under the influence of central controller  22 . In the illustrated embodiment controller  22  is positioned centrally above lifting columns  4  assuring a good communication path between the individual lifting columns  4  and the central controller  22 . 
         [0045]    Central controller  22  determines the desired control actions. This may involve receiving a measurement signal representing the actual height of a carrier of an individual lifting column that is measured with indoor positioning system  28 . In the illustrated embodiment, indoor positioning system  28  is incorporated in central controller  22 . Indoor positioning system  28  is capable of measuring position and/or speed of carrier  16 . In the illustrated embodiment indoor positioning system  28  comprises a transponder  28   a  and magnetometer  28   b  attached to carriers  16 , and a number of “satellites”  28   c  positioned in the vicinity of lifting system  2  and communicating with wired or wireless communication lines  28   d  with central controller  22 . 
         [0046]    Central controller  22  detects height differences between lifting columns, calculates the required control actions with computing means  30 , such as a processor, for individual lifting columns, and communicates the control actions to the relevant individual lifting columns. In the illustrated embodiment battery  32  provides power to central controller  22 . Alternatively, or in addition, power is provided through connection  34  to the electrical grid. Data can be stored in memory/storage  36 . Central controller  22  is provided with a wired and/or wireless connection  38  to enable connection between communication module  39  of central controller  22  to internal and/or external networks, involving internal company networks for workshop control  40 , financial control  42  and maintenance  44 , for example, and optionally to external networks  46  of suppliers and/or customers, for example. 
         [0047]    Remote control  48  is provided with additional transponder  50  to enable monitoring the position of remote control  48 . It will be understood that other tools and/or accessories can also be monitored by indoor positioning system  28 . 
         [0048]    In the illustrated embodiment there is provided wireless functionality to communicate in one or more environments such as LAN, WAN, VPN intranet, internet etc. that are schematically shown in the illustrated embodiments. Display unit  20  is further provided with input/output ports, such as USB, SD card reader, smart phone communication possibilities etc. to improve the functionality. Display  20  and/or remote control  48  may provide warning signals to the user. 
         [0049]    Optionally, central controller  22  is provided with a number of communicators/distributors  52 , such as an RF-host, that sends and/or receives signals  54  between lifting columns  4  and communicator  52 , and signals  56  between communicator/distributor  52  and central controller  22 . Communicators/distributors  52  provide additional robustness to the overall operation of the groups  2   a ,  2   b  of lifting columns  4 . 
         [0050]    In a preferred embodiment, central controller  22  is provided with monitoring system  58  that defines safety zone  60  (for illustrative purposes safety zone  60  is illustrated in  FIG. 2 ). In the illustrated embodiment group,  2   a  is provided with an inner boundary surface or wall  62  and an outer boundary surface or wall  64 . The space between walls  62 ,  64  is working zone  66  wherein an operator is allowed to operate group  2   a . On the other side of surfaces or walls  62 ,  64 , operation is locked or not authorized. Safety zone can be applied to the different types of lifting devices in the illustrated or another suitable shape. 
         [0051]    Preferably, central controller  22  ( FIG. 1 ) comprises adaptation system  68  that is capable of adjusting or adapting boundaries  62 ,  64  in directions A and B, respectively. Adaptation system  68  responds to indoor positioning system  28 . Furthermore, central controller  22  preferably comprises warning system  70  capable of sending a warning to a user or operator in case of a safety issue. For example, in case control of group  2   a  is activated outside working zone  66  a warning message is provided to remote control  48  and/or any other suitable device. Optionally, release system  72  locks and/or unlocks lifting columns  4  thereby locking and/or unlocking movement of carrier  16 . 
         [0052]    It will be understood that other configurations/designs for safety zone  60  can be envisaged in accordance with the present invention. For example, for group  2   b  a dome-shaped safety zone  74  is illustrated. Optionally, a two-wall safety zone can be provided by monitoring system  58 . Other shapes can also be provided, including circular, spherical, donut shapes etc. Optionally, the boundaries are adjustable. 
         [0053]    In the illustrated embodiment central controller  22  further comprises engagement system  76  and descent safety system  78 . Engagement system  76  may comprise camera  80  that monitors engagement of carrier  16  to vehicle  6 . Camera  80  may also operate as vehicle detector. Alternatively, separate cameras  80  and/or other appropriate sensing means are provided. Descent safety system  78  monitors descent of carrier  16  in relation to its position with indoor positioning system  28 . This enables lowering carrier  16  at a desired location. 
         [0054]    In system  2 , a user optionally performs a selection of lifting columns  4  that are incorporated in a group  2   a ,  2   b  by selecting lifting columns with a key or card  82  or other means. Optionally, controller  22  selects most suitable lifting columns  4  with indoor positioning system  28  and presents the selection to the user. Preferably, the selected group of lifting columns  4  in system  2  is provided with user instructions on one of the lifting columns  4 , using display  20  and/or remote control  50 , for example. Transmitter/receivers  24 ,  26  provide the instructions to central system controller  22 . On a central level, controller  22  determines the individual control actions to be taken for all lifting columns  4  in system  2 . Transmitter/receivers  24 ,  26  provide the control actions from the central controller to the individual lifting column  4 . Information about the actual position of carrier  16  and/or other relevant data is measured by indoor positioning system  28  and the measurement data is provided to central controller  22  that determines if and what control actions are required. In the illustrated embodiment no direct communication between individual lifting columns  4  is required. This significantly contributes to the robustness of lifting system  2 . 
         [0055]    Operation and control of a single group of lifting columns with a dedicated group controller is also possible in a similar manner as described for the two groups  2   a ,  2   b . Controller  22  is suitable for use with lifting systems comprising any number of lifting devices  4 , including systems having one, two, four or another number of columns  4 . The columns  4  may achieve lifting and lowering capability by any means known to those of skill in the art, including hydraulically, electrically, mechanically, and electromechanically. Lifting systems  2  that are compatible with the control system may be stationary and/or permanently affixed or attached to a certain location or may be mobile, capable of being transported via wheels or any other suitable means known to those in the art. With reference to the figures, like element numbers refer to the same element between drawings. 
         [0056]    Next, examples will be given of the use of indoor positioning system  28  in combination with other types of lifting devices. It will be understood that also other embodiments according to the present invention can be envisaged. 
         [0057]    For example, a four-post lifting system  102  ( FIG. 2 ) comprises four columns  104  carrying runways  106 . Preferably, each column  104  has one transponder  28   a  and compass  28   b . In the illustrated embodiment an indicator  110  with a green light  112  and a red light  114  is provided. Light  110  signals to the driver when vehicle  6  is positioned correctly relative to columns  104  and the vehicle  6  can be lifted. In case each column  104  is connected to indoor positioning system  28  the position of the carrier/runways  106  can be checked. This contributes to the overall safety of the lifting operation. 
         [0058]    As a further example, lifting system  202  ( FIG. 3 ) comprises a so-called sky-lift configuration with four posts  204  carrying runways  206 . In the illustrated embodiment transponder  28   a  and compass  28   b  is provided for every post  204 . This enables the check on positioning of the carrier as described earlier by calculating the height of runways  206  from the orientation of posts  204 , for example. Optionally, transponder  28   a  is provided directly on or at runways  206 . A light  210  with green  212  and red  214  lights can be provided on wall  216  to indicate to the driver of vehicle  6  that the vehicle is positioned correctly or needs to be repositioned. 
         [0059]    As an even further example, lifting system  302  ( FIG. 4 ) comprises a so-called two-post configuration with two posts  304  that are provided with carrier arms  306 . In the illustrated embodiment, to measure position and speed of carrier arms  306  transponder  28   a  is provided. This enables the check on positioning of arms  306  as described earlier. A light  310  with green  312  and red  314  lights can be provided to indicate to the driver of vehicle  6  that the vehicle is positioned correctly or needs to be repositioned. 
         [0060]    Providing arms  306  with transponders  28   a  enables monitoring the position and level of extension of arms  306 . This enables dynamic adjustment of the maximum load, as a long arm reduces maximum load and a short arm increases maximum load. Load can be measured with load cell  316 . 
         [0061]    In a further alternative embodiment lifting system  402  ( FIG. 5  A-B) is of the in-ground lift type comprising stationary lifting column/device  404  and a moveable lifting column/device  406  that are located on or in floor  408 . The front lifting column/device  404  is provided in cassette or box  410  with a telescopic lifting cylinder  412 . On top of cylinder  412  there is provided carrier  414  with axle carriers  416 . In the illustrated embodiment wheel hatches or wheel recesses  418  are provided. Hatches/recesses  418  define the position of the front wheels of the vehicle. Furthermore, in the illustrated embodiment a hatch  420  is provided in front of the front lifting column/device  404  for maintenance, for example. 
         [0062]    The moveable lifting column/device  406  moves in cassette or box  422  comprising a telescopic lifting cylinder  430 . Box  422  provides a pit with a slot or recess  424  for guiding the moveable lifting column/device  406 . Moveable lifting column/device  406  is provided with carrier  426  whereon axle carriers  428  are mounted. Depending on the type of vehicle  432  additional adapters can be provided that cooperate with carriers  414 ,  426  to enable engagement with different axle dimensions. 
         [0063]    Columns/devices  404 ,  406  are provided with transponders  28   a . When storing column  406  descent system  78  controls the position of column/device  406  relative to hatches/recesses  434 . Optionally, this can be performed automatically by controller  22 . 
         [0064]    In an alternative lifting system  502  of the in-ground type ( FIG. 6 ) the telescopic lifting cylinders  412 ,  430  of lifting system  402  are replaced by scissor type lifts  504 ,  506 . It will be understood that operation of lifting systems  402 ,  502  of the in-ground type is similar. 
         [0065]    It will be understood that the invention can be applied to a range of lifting systems, including but not limited to four-post and two-post lifting columns, such as the Stertil-Koni one post lifts ST1075, the Stertil-Koni two post lifts SK 2070, and the Stertil-Koni four post lifts ST 4120, skylift, mobile columns, and in-ground lifts, such as the Stertil in-ground Ecolift and the Stertil in-ground Diamond lift. Also, it will be understood that additional embodiments of the invention can be envisaged combining and/or switching features from the described and/or illustrated embodiments. For example, instead of light  110 ,  210 , or in addition thereto, sound signals, indications on a control system etc. can be applied. 
         [0066]    When vehicle  6 ,  432  needs to be lifted, lifting system  2 ,  102 ,  202 ,  302 ,  402 ,  502  is activated. For example, a user can activate the lifting system with remote control  48 . Preferably, a safety zone  60 ,  74  is provided to increase the overall safety. The size of these zones can be adjusted depending on vehicle type and/or carrier height. Carrier height is determined using indoor positioning system  28  in combination with transponders  28   a , electronic compass  28   b  and “satellites”  28   c . In case of mobile lifting columns  4 , the selection of specific lifting column  4  to be included in a group  2   a ,  2   b  can be done by central controller  22  using information of the specific location and carrier height of available lifting columns  4 , for example. Such selection can be presented to the user as a suggestion that requires authorization by the user or can be selected automatically by controller  22 . Release system  22  may lock/unlock carrier  16  as an additional safety measure. In case someone or something enters specific parts of safety zone  60 ,  74 , central controller  22  is informed and may instruct release system  72  to lock carrier  16 . Carrier  16  can be unlocked after the person or object is removed from safety zone  60 ,  74 , for example. This can be performed automatically or requires user authorization or user input. Positions of persons and/or objects including tools and accessories can be controlled by providing additional transponders  50  in these tools and/or objects. This further enables monitoring and control of the engagement of carrier  16  to vehicle  6 ,  432  when involving these tools, such as an axle stand, transmission jack or wheel dolly, for example. 
         [0067]    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. The present invention is described using a lifting device such as a lifting column and more specifically a mobile lifting column. The invention can also be applied to other type of lifting columns such as so-called boom-lifts, scissor-lifts and loading platforms. Such lifting equipment can be provided with the measures illustrated above according to the invention.