Lifting mechanism with a lifting box arranged to be movable in one direction of movement relative to a supporting part of the lifting mechanism, and method for operating a lifting mechanism

Description

[0001] The invention relates to a lifting mechanism with a lifting box arranged to be movable relative to a supporting part of the lifting mechanism in a direction of movement and to a method for operating a lifting mechanism.

[0002] It is generally known that a lifting part can be moved vertically by means of a lifting mechanism.

[0003] From the CN 201 713 264 U The closest state of the art is a hoist.

[0004] From DE102017010448A1 and US8776725B, lifting mechanisms for adjusting the height of food bowl holders are known.

[0005] From the US 3 563 341 A a forklift is known.

[0006] From the US 2010 / 102284 A1 is a lifting device for vehicles known.

[0007] From the EP 2 767 500 A1 An electric lifter is known.

[0008] The invention is therefore based on the object of further developing and making operable a lifting mechanism in a safe manner.

[0009] According to the invention, the object is achieved in the lifting gear according to the features specified in claim 1 and in the method according to the features specified in claim 14.

[0010] Important features of the invention in the lifting mechanism with a lifting box arranged to be movable relative to a supporting part of the lifting mechanism in a direction of movement, wherein the support part is placed on a base plate and connected to this base plate, wherein at least one linear guide, at least one conductor rail and a toothed rack are fastened to the support part, wherein an electric motor is arranged in the lifting box, wherein a gear is in engagement with the toothed rack and is connected in a rotationally fixed manner to a shaft of the electric motor, wherein a lifting part is connected to the lifting box, wherein the vertical projection of the lifting part onto a plane whose normal direction is aligned parallel to the direction of movement is contained in the vertical projection of the base plate onto this plane, in particular is therefore encompassed by it.

[0011] The advantage here is that the lifting mechanism is stable and easy to operate, preventing tipping. Furthermore, the electric motor drive of the lifting box is located within the lifting box itself and is thus protected. The supporting part ensures high stability and, at the same time, precise alignment of the linear guides, the rack, and the conductor rails to one another, as these components are all mounted on the same part. Relative alignment is therefore easy and very precise during assembly.

[0012] In an advantageous embodiment, the lifting part is attached to a front side of the lifting box, and the base plate protrudes further toward the front than the lifting part, particularly to prevent the lifting mechanism from tipping over. This is advantageous because tipping over is prevented, thus improving safety.

[0013] In an advantageous embodiment, the base plate is made of steel, and the wall thickness of the base plate is greater than the wall thickness of the supporting part, particularly the rear wall of the supporting part. The advantage here is that the base plate is heavy, thus ensuring safety.

[0014] In an advantageous embodiment, the electric motor comprises a gearbox, in particular the electric motor is a geared motor, with the shaft being the output shaft of the gearbox. This is advantageous in that a high torque can be generated, thus enabling a large mass to be moved.

[0015] In an advantageous embodiment, the transmission is designed to be self-locking, in particular such that the transmission transmits a torque flow from the input shaft of the transmission, designed as the rotor shaft of the electric motor, to the output shaft of the transmission and inhibits a torque flow from the output shaft of the transmission to the input shaft of the transmission, designed as the rotor shaft of the electric motor. This has the advantage that movement is prevented when the electric motor is not energized. This increases safety.

[0016] In an advantageous embodiment, the supporting part, in particular a rear wall of the supporting part, is designed as the first leg of an L-shaped part, and the base plate is placed on the other leg of the L-shaped part. The advantage here is that high stability and thus safety can be achieved.

[0017] In an advantageous embodiment, the supporting part is constructed in several pieces, comprising two side wall sections and a rear wall connected to these side wall sections. This allows for a stable, cost-effective construction.

[0018] In an advantageous embodiment, a guide part is attached to the lifting box, which is operatively connected to the linear guide. In particular, the guide part is constructed in two pieces, with the two pieces of the guide part being spaced apart from each other in the direction of movement. This is advantageous in that very good alignment and a high level of safety can be achieved. This spacing allows the two pieces to be arranged far apart, thus achieving high stability.

[0019] In an advantageous embodiment, two guide parts, particularly those spaced apart vertically and / or transversely to the direction of movement, are attached to the lifting box. These guide parts are positively connected to the linear guides and have only a single translational degree of freedom, which enables the linear movement of the guide parts and / or the lifting box along the linear guides. The advantage of this is that high stability and thus safety can be achieved while simultaneously minimizing material consumption and mass.

[0020] In an advantageous embodiment, brushes are attached to the lifting box or the electric motor, which contact the power rails. The advantage here is that the lifting box can be electrically supplied via a cost-effective sliding contact.

[0021] In an advantageous embodiment, a secondary winding is arranged on the lifting box or on the electric motor, which is inductively coupled to at least one of the busbars, which is supplied with an alternating current, wherein a capacitor is connected in parallel or in series with the secondary winding such that the resonant frequency of the thus formed resonant circuit equals the frequency of the alternating current impressed into the busbar, wherein a rectifier arranged on the lifting box or on the electric motor is fed from the resonant circuit, from which the electric motor is supplied, in particular wherein a smoothing capacitor is arranged on the DC side connection of the rectifier, in particular parallel to the electric motor. The advantage here is that a contactless supply to the lifting box is possible.

[0022] In an advantageous embodiment, the respective busbar is designed as a tube half, in particular as a copper tube half. This is advantageous because it allows for simple production of the busbars.

[0023] In an advantageous embodiment, the rear wall is made of metal and an electrical insulator is arranged between the rear wall and the respective busbar

[0024] In an alternative advantageous embodiment, the rear wall is made of an electrically insulating material, in particular plastic, and the respective busbar is located on the rear wall.

[0025] The advantage is that a high level of stability and therefore safety can be achieved.

[0026] In an advantageous embodiment, an operating unit, in particular an HMI interface, is arranged on the support part, in particular at the upper end of the support part. The operating unit has at least one input element, in particular a selector switch, a display, and a microprocessor. This is advantageous in that a high level of security can be achieved because information can be clearly displayed and operation can be carried out by pressing input elements, in particular a changeover switch or selector switch, in a vertical direction.

[0027] In an advantageous embodiment, the microprocessor is connected to a reader, in particular an NFC reader or RFID reader, wherein the microprocessor is configured such that, depending on the information read from a tag, in particular an RFID tag or NFC tag, the lifting box is moved to a linear position, in particular to an upper or a lower position, in particular wherein the movement of the lifting box is stopped when the tag is in the immediate vicinity of the lifting box, in particular therefore the vertical projection of the tag onto the plane is contained in the vertical projection of the base plate onto this plane, in particular therefore is encompassed by it, in particular wherein the tag is arranged on a mobile device, in particular on a vehicle, on a pet or on a person. The advantage here is that the height position of the lifting gear is controlled depending on the information stored on the tag and read by the reading device. Furthermore, if the tag is too close, the movement of the lifting box can be stopped.

[0028] In an advantageous embodiment, a current sensor is arranged in the hoist, which detects the current flowing through the busbars. The microprocessor is configured and controls the current flowing in the busbars in such a way that the detected current value is compared with a threshold value. If the threshold value is exceeded, the hoist is placed in a safe state, in particular, the power supply is switched off or the hoist is moved to a lower position. This is advantageous because a safe state is activated in the event of danger.

[0029] In an advantageous embodiment, a current sensor is arranged in the hoist, which detects the current flowing through the busbars, and a sensor for detecting the voltage applied to the electric motor is arranged in the hoist, The microprocessor is configured and controls the current flowing in the busbars in such a way that the power of the electric motor is determined from the detected current value and the detected voltage value, the presence of the containers and / or the mass accommodated in the containers being detected and / or determined from the power thus determined, and the lifting gear is brought into a safe state, in particular the power supply can be switched off or the lifting gear can be brought to a lower position, if the detected and / or determined mass exceeds a threshold value. The advantage here is that a safe state is activated in the event of danger.

[0030] Important features in the method for operating an aforementioned lifting gear are that, depending on the information read from a tag, in particular an RFID tag or NFC tag, the lifting box is moved to a linear position, in particular to an upper or a lower position, in particular wherein the travel movement of the lifting box is stopped when the tag is in the immediate vicinity of the lifting box, in particular therefore the vertical projection of the tag onto the plane is contained in the vertical projection of the base plate onto this plane, in particular therefore is encompassed by it, in particular wherein the tag is arranged on a mobile part, in particular on a vehicle, on a pet or on a person.

[0031] The advantage of this is that a safe state is activated in the event of danger. In particular, it prevents the lifting part from being moved vertically onto the mobile part.

[0032] In an advantageous embodiment, the current flowing through the busbars is detected and controlled such that, after comparing the detected current value with a threshold value, if this threshold value is exceeded, the lifting mechanism is brought into a safe state, in particular, the power supply is switched off or the lifting mechanism is moved to a lower position. This is advantageous because a safe state is activated in the event of danger. In particular, this prevents the lifting part from being moved vertically onto the mobile part.

[0033] In an advantageous embodiment, the current flowing through the busbars is detected and the voltage applied to the electric motor is detected and from this a measure of the power of the electric motor is determined and from this measure a value of a mass accommodated in the containers is determined and / or the presence of the containers is detected, The lifting mechanism is brought into a safe state, in particular the power supply is switched off or the lifting mechanism is brought to a lower position, in particular the end position, if the detected and / or determined mass exceeds a threshold value, in particular, and otherwise, if the containers are not present, the lifting box is brought to an upper position, in particular the end position. The advantage here is that a safe state is activated in the event of danger. In particular, this prevents the lifting part from being moved vertically onto the mobile part.

[0034] Further advantages emerge from the dependent claims. The invention is not limited to the combination of features in the claims. Further possible combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent to those skilled in the art, particularly from the problem and / or the problem posed by comparison with the prior art.

[0035] The invention will now be explained in more detail using schematic illustrations: In the Figure 1 a lifting mechanism according to the invention with a folding wall 4 and a lifting part 5 is shown in an oblique view. Figure 2 The lifting mechanism is shown in section. Figure 3 The lifting mechanism is shown without folding wall 4. In the Figure 4 the lifting part 5 is shown in an oblique view.

[0036] As shown in the figures, the lifting mechanism has a base plate 1, which is preferably made of steel.

[0037] A support member 2 is attached to the base plate 1, which accommodates an operating unit 3, in particular an HMI interface, on its upper side. The operating unit 3 has input means and display means (31, 32).

[0038] A selector switch 30 is provided as an input means, with which the direction of travel of the lifting part 5 can be controlled, which is connected to a lifting box 20 in which an electric motor 21, in particular a DC motor, is accommodated, which drives a gear 22 directly or via an intermediate gear.

[0039] The gear 22 engages with a rack 23 which is attached to the supporting part 2.

[0040] The lifting part has two recesses, in each of which a container 6, in particular a trough or bowl, is received.

[0041] A first recess is arranged on a first side of a plane whose normal direction is aligned parallel to the connecting line between the centers of gravity of the two recesses, in particular of the two containers 6. Preferably, the plane intersects busbars 25, which are attached to the support member 2 and are vertically oriented, i.e., extend along the support member 2, or intersects the rack 23.

[0042] The second recess is located on the other side of the plane.

[0043] Sliding contacts, in particular brushes, are arranged on the lifting box 20, by means of which electrical current can be diverted from the busbars 25 to supply the electric motor 21. Preferably, only a single pair of busbars 25 is provided, which makes it possible to supply the electric motor 21 with DC voltage.

[0044] The interior area surrounded by the supporting part 2 is covered by a folding wall 4 arranged on the supporting part 2.

[0045] During the linear movement of the lifting box 20 along the power rails 25, the folding wall is moved accordingly and covers the interior area in every position of the lifting box 20.

[0046] The rack 23 is arranged parallel to the busbars 25.

[0047] In addition, at least two linear guides 24 are arranged parallel to the rack 23 and to the busbars 25 on the supporting part 2.

[0048] The linear guides 24 are preferably aligned in the vertical direction, in particular in the direction of the Earth's gravitational field.

[0049] By means of the selector switch 30, the polarity of the busbars 25 can be specified and thus the direction of rotation of the electric motor 21 in the forward direction or reverse direction can be specified.

[0050] When the electric motor 21 is operated in the forward direction, the first indicator 31, in particular a light, is activated. In particular, the first indicator 31 illuminates, but in particular the second indicator 32 does not.

[0051] When the electric motor 21 is operated in the reverse direction, the second indicator 32, in particular a light, is activated. In particular, the second indicator 31 illuminates, but in particular the first indicator 31 does not.

[0052] Two guide parts 40 spaced apart from one another are attached to the lifting box 20, which are positively connected to the linear guides 24 and have only one degree of freedom, which enables the linear movement along the linear guides 24.

[0053] The busbars 25 and the rack 23 are arranged between the two linear guides 24.

[0054] Preferably, the linear guides 24, the busbars 25 and the rack 23 are arranged on a flat surface area of ​​the support part 2.

[0055] By means of the large spacing of the two linear guides 24 from each other, a stable linear guide of the lifting box 20 can be achieved.

[0056] The area covered by the lifting box 20 in the direction of movement, in particular in the vertical direction, comprises the area covered by the gear 22 and the electric motor 21, in particular including the gearing, in the direction of movement. Thus, the electric motor 21, including the gear 22, can be completely accommodated in the lifting box 20. Furthermore, stable guidance is achieved, since the guide parts 40 extend over a large length in the direction of movement.

[0057] Furthermore, a housing part of the electric motor 21, in particular the stator housing of the electric motor 21, is connected, in particular fixedly connected, to the lifting box 20. The rotor shaft of the electric motor is connected in a rotationally fixed manner to the gear 22 and is rotatably mounted in the lifting box 20 at the end region of the rotor shaft facing away from the electric motor 21, in particular by means of plain bearings or roller bearings. This allows for increased stability.

[0058] The supporting part 2 is preferably designed in several pieces, having two side wall parts and a rear wall connected to these side wall parts.

[0059] The base plate 1 is preferably made of cast iron, cast steel, or a ferrous material. The rear wall of the support part 2 is flush with the edge of the base plate 1. The vertical projection of the lifting part 5 onto a plane whose normal direction is parallel to the direction of movement is contained in the vertical projection of the base plate 1 onto this plane, in particular encompassed by it. Thus, the base plate protrudes further toward the front than the lifting part 5. This prevents the lifting mechanism from tipping over toward the lifting part 5.

[0060] The rear wall of the support section 2 is, for example, leaned against, positioned against, or connected to a building wall. This prevents the lifting mechanism from tipping over either toward the rear wall or toward the lifting section 5.

[0061] The two side wall parts also function as guides for the folding wall 4. The folding wall 4 is preferably made of a plastic, in particular of an elastic plastic.

[0062] The lifting part 5 is preferably made of aluminum or wood. The lifting box 20 is preferably made of metal, in particular aluminum.

[0063] Each of the guide parts 40 is constructed in two pieces, with these two pieces of the guide parts 40 being spaced apart from each other in the direction of movement and aligned with each other in the direction of movement. This achieves increased mechanical stability in the guide. Furthermore, only short pieces are required, saving material. These pieces are mounted on the lifting box 20 as far apart as possible in the direction of movement, in particular flush with an edge of the lifting box 20, i.e., flush with the upper or lower edge of the lifting box 20.

[0064] The busbars 25 are preferably manufactured by halving a copper tube, in particular with the cutting plane containing the rotational axis of symmetry of the cylindrical tube. Thus, each busbar 25 is designed as half a cylinder.

[0065] The brushes arranged on the lifting box 20 are in sliding contact with the busbars 25. Since the busbars have a semi-cylindrical recess, secure contact of the brushes with the busbars 25 is guaranteed. Lateral slipping of the brushes or even just one of the brush bristles can be prevented by appropriate dimensioning, in particular by immersing the brushes as deeply as possible.

[0066] Limit switches are also arranged on the supporting part 2, so that when the respective limit switch comes into contact with the lifting box 20, the power supply to the electric motor is terminated.

[0067] An electronic control unit comprising a microprocessor is arranged in the control unit 3 arranged on the upper side of the support part 2. The microprocessor is supplied with power from a voltage regulator of the control unit, in particular a 5 volt voltage regulator. The voltage regulator is supplied with power from a switched-mode power supply which is supplied on the input side by a mains-fed rectifier. On the output side, the switched-mode power supply provides a first supply voltage for the voltage regulator and a second supply voltage for a second voltage regulator, in particular an 18 volt voltage regulator, which supplies the electric motor via the busbars 25 and the sliding contact created by the brushes. It is important that the voltage provided by the second voltage regulator is greater than the voltage provided by the first voltage regulator.The same applies to the power supplied by the two voltage regulators. Controllable switches, particularly relays, are arranged between the second voltage regulator and the two power rails 25. The control signals for the two controllable switches are provided by the microprocessor. Thus, each of the power rails 25 can be switched off separately.

[0068] The operating unit has a selector switch 30 as input means and, depending on the input, controls the first display means 31, in particular a light, and the second display means 32, in particular a light.

[0069] In addition, a reader, in particular an RFID reader or NFC reader, is arranged in the electronic control system, wherein a tag, in particular an RFID tag or NFC tag, can be read within a certain range by means of the reader. Depending on the information stored in the tag, the lifting box is then moved, i.e., to an upper or lower position. Upon actuation of the selector switch 30, the information from the tag is given lower priority, thus executing the direction of movement specified by the selector switch 30.

[0070] For example, a mobile device equipped with the tag, in particular a vehicle, a pet, or a person, approaches the lifting mechanism. As soon as the tag is within range, the lifting box 20 is moved to the corresponding height associated with the information stored in the tag. For example, when a mobile device approaches that is to refill the containers 6, the lifting box 20 is moved to the upper position, and when another mobile device approaches, the lifting box 20 is moved to the lower position.

[0071] Thus, depending on the type of mobile unit approaching the lifting mechanism, the lifting box is moved to a different position.

[0072] However, if the handset gets too close to the lifting part or the lifting box, the movement is stopped to prevent a collision in the direction of travel between the handset and the lifting part. This prevents, for example, the lifting part from lowering onto the handset.

[0073] Since the rack 23 is attached to the rear wall of the support part 2, and the linear guides 24 and the busbars 25 are also attached to the rear wall, a highly precise alignment in the direction of movement is achievable. This is because the rear wall is manufactured as a single piece, and thus the relative alignment is fixed during assembly of the rack 23, the linear guides 24, and the busbars 25. Preferably, the rear wall is made of an electrically insulating material, in particular plastic, or the rear wall is made of a metal, in particular aluminum or steel, with an insulator interposed between the busbars 25 and the rear wall, and the fastening screws that press the busbars 25 against the rear wall also being made of an electrically insulating material.

[0074] In further embodiments of the invention, a self-locking gear, particularly a worm gear, is interposed between the gearwheel and the electric motor. This secures the lifting box 20 in a high position even when the electric motor is switched off, i.e., not supplied with power. Alternatively or additionally, an electromagnetically actuated brake is also arranged on the motor. This securely holds the lifting box 20 in one position.

[0075] In further embodiments according to the invention, a current sensor is arranged in the hoist, which detects the current flowing through the busbars. The power of the electric motor can thus be determined from the detected current value and the voltage supplying the electric motor. The power required for an empty run is stored in a memory connected to the microprocessor of the control system, in particular for the upward travel on the one hand and for the downward travel on the other. Thus, by detecting the power, the presence of the containers 6 and the mass accommodated in the containers 6 can be determined. If this mass exceeds a threshold value, a warning can be displayed and / or the hoist can be brought into a safe state, in particular the power supply can be switched off or the hoist can be brought to a lower position.

[0076] In further embodiments of the invention, an inductive supply is used instead of the sliding contact supply. For this purpose, the busbars 25 are supplied with a medium-frequency alternating current by the electronic control system, in particular with a frequency between 10 kHz and 1 MHz. Instead of brushes, a secondary winding is arranged on the lifting box 20, which is inductively coupled to the busbars. Preferably, an E-shaped ferrite core is attached to the lifting box, with the secondary winding wound on the ferrite core. A central leg of the E-shaped ferrite core extends between the two busbars 25. The other two legs of the E-shaped ferrite core protrude next to the busbars 25 toward the supporting part 2.A capacitor is connected in parallel or in series to the secondary winding, dimensioned such that the resonant frequency of the resulting resonant circuit equals the frequency of the alternating current impressed on the busbars 25. In this way, high efficiency can be achieved even with low inductive coupling strength. The resonant circuit supplies a rectifier, which supplies the electric motor. Polarity reversal of the electric motor can be achieved by a polarity reversal unit arranged between the rectifier and the electric motor, preferably effected by controllable electronic semiconductor switches.The control signal for the polarity reversal unit is transmitted from the control unit via the inductive coupling to the polarity reversal unit arranged on the lifting box, which provides the electric motor, which is preferably designed as a DC motor, with an appropriately polarized supply voltage. In a further development, the polarity reversal unit can also be designed as a relay, so that an electrical disconnection of the electric motor can also be effected. List of reference symbols

[0077] 1 Base plate 2 Supporting part 3 Operating unit, in particular HMI interface 4 Folding wall 5 Lifting part 6 Container, in particular trough or bowl 20 Lifting box 21 Electric motor 22 Gear 23 Rack 24 Linear guide 25 Busbars 30 Selector switch 31 First display means, in particular light 32 Second display means, in particular light 40 Guide part

Claims

1. A lifting unit having a lifting box (20), movably arranged relative to a support part (2) of the lifting unit in a motion direction, wherein the support part (2) is mounted on a base plate (1) and is connected to this base plate (1), wherein at least one linear guide (24) and a rack (23) are secured to the support part (2), wherein an electric motor (21) is arranged in the lifting box (20), wherein a toothed wheel (22) engages the rack (23) and is connected in a rotationally-fixed manner to a shaft of the electric motor (21), wherein a lifting part (5) is connected to the lifting box (20), characterised in that at least one bus bar is secured to the support part (2), and in that the perpendicular projection of the lifting part (5) onto a plane, whose normal direction is oriented parallel to the motion direction, is contained in the perpendicular projection of the base plate (1) onto this plane, in particular therefore is encompassed by it.

2. A lifting unit according to claim 1, characterised in that the lifting part (5) is secured to a front side of the lifting box (20) and the base plate (1) projects towards the front side further than the lifting part (5), in particular to prevent the tipping over of the lifting unit, and / or in that the base plate (1) is manufactured of steel and the wall thickness of the base plate (1) is greater than the wall thickness of the support part (2), in particular the rear wall of the support part (2), and / or in that the electric motor (21) comprises a gear unit, in particular therefore the electric motor (21) is a geared motor, wherein the shaft is the output shaft of the gear unit.

3. A lifting unit according to any one of the preceding claims, characterised in that the gear unit is self-locking, in particular such that the gear unit passes a torque flow from the input shaft, in the form of a rotor shaft of the electric motor (21), of the gear unit to the output shaft of the gear unit and blocks a torque flow from the output shaft of the gear unit to the input shaft, in the form of a rotor shaft of the electric motor (21), of the gear unit.

4. A lifting unit according to any one of the preceding claims, characterised in that the support part (2), in particular a rear wall of the support part (2), is in the form of a first limb of an L-shaped part and the base plate (1) is placed onto the other limb of the L-shaped part.

5. A lifting unit according to any one of the preceding claims, characterised in that the support part (2) is multi-piece, wherein it has two lateral wall parts and a rear wall connected to these lateral wall parts.

6. A lifting unit according to any one of the preceding claims, characterised in that a guide part (40) is secured to the lifting box (20), which guide part is in an operative connection with the linear guide (24), in particular wherein the guide part (40) is two-piece, wherein the two pieces of the guide part (40) are spaced apart from one another in a motion direction.

7. A lifting unit according to any one of the preceding claims, characterised in that two guide parts (40), in particular spaced apart from one another perpendicularly and / or transversely to the motion direction, are secured to the lifting box (20), which guide parts are connected to the linear guides in a form-locked manner and here have only a single translatory degree of freedom, which enables the linear motion of the guide parts (40) and / or of the lifting box (20) along the linear guides, and / or in that brushes are secured to the lifting box (20) or to the electric motor (21) and contact the bus bars (25).

8. A lifting unit according to any one of the preceding claims, characterised in that a secondary winding is arranged at the lifting box (20) or at the electric motor (21) and is inductively coupled to at least one of the bus bars (25), which is acted upon by an alternating current, wherein a capacitor is connected in parallel or in series to the secondary winding such that the resonance frequency of the thus formed resonating circuit equals the frequency of the alternating current impressed upon the bus bar, wherein a rectifier arranged at the lifting box (20) or at the electric motor (21) is fed from the resonating circuit, the electric motor (21) being supplied from the rectifier, in particular wherein a smoothing capacitor is arranged at the DC-side connection of the rectifier, in particular parallel to the electric motor (21).

9. A lifting unit according to any one of the preceding claims, characterised in that the respective bus bar is in the form of a pipe half, in particular a copper pipe half.

10. A lifting unit according to any one of the preceding claims, characterised in that - the rear wall is made of metal and an electrical insulator is arranged between the rear wall and the respective bus bar or in that - the rear wall is made of an electrically insulating material, in particular plastics material, and the respective bus bar contacts the rear wall.

11. A lifting unit according to any one of the preceding claims, characterised in that an operating unit (3), in particular HMI interface, is arranged at the support part (2), in particular at the upper end of the support part (2), wherein the operating unit (3) has at least one input element, in particular selector switch (30), a display means (31, 32) and a microprocessor.

12. A lifting unit according to any one of the preceding claims, characterised in that the microprocessor is connected to a reader, in particular NFC reader or RFID reader, wherein the microprocessor is configured such that the lifting box (20) is moved to a linear position, in particular to an upper or to a lower position, dependent on the information retrieved from a tag, in particular RFID tag or NFC tag, in particular wherein the travel motion of the lifting box (20) is stopped when the tag is located in close range of the lifting box (20), in particular therefore the perpendicular projection of the tag onto the plane is contained in the perpendicular projection of the base plate (1) onto this plane, in particular therefore is encompassed by it, in particular wherein the tag is arranged on a mobile part, in particular on a vehicle, on a domestic animal or on a person.

13. A lifting unit according to any one of the preceding claims, characterised in that a current sensor is arranged in the lifting unit and detects the current flowing through the bus bars (25), wherein the microprocessor is configured and controls the current flowing in the bus bars (25) such that the detected value of the current is compared with a threshold value and the lifting unit is brought into a safe state when the threshold value is exceeded, in particular the current supply is switched off or the lifting unit is brought to a lower position, and / or in that a current sensor is arranged in the lifting unit and detects the current flowing through the bus bars (25), and a sensor for detecting the voltage applied to the electric motor (21) is arranged in the lifting unit, wherein the microprocessor is configured and controls the current flowing in the bus bars (25) such that the power of the electric motor (21) is determined from the detected current value and from the detected voltage value, wherein the presence of the containers (6) and / or the mass received in the containers is detected and / or determined from the power determined in this manner, wherein the lifting unit is brought into a safe state, in particular the current supply can be switched off or the lifting unit can be brought to a lower position, when the detected and / or determined mass exceeds a threshold value.

14. A method of operating a lifting unit according to any one of the preceding claims, characterised in that the lifting box (20) is moved to a linear position, in particular to an upper or to a lower position, dependent on the information retrieved from a tag, in particular RFID tag or NFC tag, in particular wherein the travel motion of the lifting box (20) is stopped when the tag is located in close range of the lifting box (20), in particular therefore the perpendicular projection of the tag onto the plane is contained in the perpendicular projection of the base plate (1) onto this plane, in particular therefore is encompassed by it, in particular wherein the tag is arranged on a mobile part, in particular on a vehicle, on a domestic animal or on a person.

15. A method according to claim 14, characterised in that the current flowing through the bus bars (25) is detected and is controlled such that after comparison of the detected value of the current with a threshold value, the lifting unit is brought into a safe state when this threshold value is exceeded, in particular the current supply is switched off or the lifting unit is brought to a lower position, and / or in that the current flowing through the bus bars (25) is detected and the voltage applied to the electric motor (21) is detected and a measurement for the power of the electric motor (21) is determined therefrom and from this measurement there is determined a value of a mass received in the containers and / or there is detected the presence of the containers (6), wherein the lifting unit is brought into a safe state, in particular the current supply is switched off or the lifting unit is brought to a lower position, in particular end position, when the detected and / or determined mass exceeds a threshold value, in particular and wherein otherwise the lifting box (20) is brought to an upper position, in particular end position, when the containers (6) are not present.