Lifting apparatus

Abstract

The invention relates to a lifting apparatus for raising and lowering a work platform (2) relative to a base frame (3), having a base frame (3), a work platform (2), at least one first stationary linear guide rail (4.1) fastened to the base frame (3) at an acute angle, and at least one second stationary linear guide rail (4.1) fastened to the base frame (3) at the same acute angle mirror-symmetrically to the first stationary linear guide rail (4.1), at least one first liftable linear guide rail (5.1) which is connected to the work platform (2) at an opposite acute angle, and at least one second liftable linear guide rail (5.2) which is connected to the work platform (2) at an acute angle mirror-symmetrically to the first liftable linear guide rail (5.1), and at least one first sliding block element (6.1) which has a first sliding block body (6a) which is mounted on the first stationary linear guide rail (4.1) so as to be guided in a longitudinally displaceable manner and has a second sliding block body (6b) which is mounted on the first liftable linear guide rail (5.1) so as to be guided in a longitudinally displaceable manner, and at least one second sliding block element (6.2) which has a third sliding block body (6c) which is mounted on the second stationary linear guide rail (4.2) so as to be guided in a longitudinally displaceable manner and has a fourth sliding block body (6d) which is mounted on the second liftable linear guide rail (5.2) so as to be guided in a longitudinally displaceable manner.

Description

[0001] lifting device

[0002] The invention relates to a lifting device for raising and lowering a work platform relative to a base frame.

[0003] EP 1 190 981 A1 describes a scissor lift table with a lower frame, an upper frame forming a working plane or a table, and a scissor mechanism acting between the lower frame and the upper frame, wherein the scissor mechanism comprises intersecting inner and outer scissor links which can be actuated to raise or lower the upper frame, and wherein drive means are assigned to at least one pair of the intersecting scissor links, and wherein two curves are assigned to one scissor link and two carriages, slides or the like which can be moved towards and away from one another on the curves along the scissor link are assigned to the other scissor link as drive means.

[0004] EP 2 019 076 A1 describes a scissor lifting device with at least two scissor links connected in pairs by a pivot axis, wherein the pivot axis is arranged between the respective end sections of the scissor links, and with a drive for raising and lowering the scissor links by means of a traction means, wherein the scissor lifting device is equipped with two coupling bridges connected by a guide and with push struts pivotably arranged on a coupling bridge, which are each pivotably connected to a scissor link, wherein at least one coupling bridge carries a deflection pulley for the traction means, and wherein one coupling bridge is equipped with the push struts, which are each connected to a scissor link on a common side with respect to the pivot axis, and the other coupling bridge is equipped with an expansion body,which, on a side facing away from the thrust struts, rests against two curved contact tracks, each associated with a scissor link, in relation to the pivot axis.

[0005] The object of the invention is to provide a lifting device for raising and lowering a work platform relative to a base frame, which has a compact structure in a lowered state and is constructed from the simplest and most cost-effective machine elements possible.

[0006] The object is achieved by a lifting device for raising and lowering a work platform relative to a base frame, comprising:

[0007] - a base frame,

[0008] - a work platform,

[0009] - at least one first stationary linear guide rail fastened to the base frame at an acute angle and at least one second stationary linear guide rail fastened to the base frame at the same acute angle and mirror-symmetrically to the first stationary linear guide rail

[0010] Linear guide rail,

[0011] - at least one first lifting linear guide rail connected to the work platform at an opposite acute angle and at least one second lifting linear guide rail connected to the work platform at an acute angle mirror-symmetrically to the first lifting linear guide rail, and

[0012] - at least one first sliding block element which has a first sliding block body which is mounted on the first stationary linear guide rail in a longitudinally adjustable manner and a second sliding block body which is mounted on the first linear guide rail which is movable in a longitudinally adjustable manner, and

[0013] - at least one second sliding block element which has a third sliding block body which is mounted on the second stationary linear guide rail in a longitudinally adjustable manner and a fourth sliding block body which is mounted on the second linear guide rail which is movable in a longitudinally adjustable manner.

[0014] The base frame can have a base plate, a supporting frame or other means of support by means of which the entire lifting device can be set up at a desired location. The desired location can be a fixed area, such as the floor in a building or in a hall. Instead of a fixed installation of the lifting device, the lifting device can also be attached to a vehicle. For this purpose, the lifting device can be fastened to a running gear or chassis of the vehicle by means of the base frame. The base frame of the lifting device can then also be a component of the vehicle, if necessary. The vehicle can be, for example, a driverless transport vehicle, in particular an autonomous vehicle. The vehicle can, for example, be equipped with omnidirectional wheels in order to be able to move the lifting device not only on a level surface, but also to rotate or turn it around any pivot point.The base frame can also comprise or form fastening means in order to be able to attach the lifting device to the vehicle.

[0015] The work platform can form a closed-surface work platform or a support platform. Objects such as components in a production and / or assembly environment can be stored and transported on this work platform. Such objects can be picked up by raising the work platform. The transported objects can be put down again by lowering the work platform. The lifting device can also be used to precisely position the raised object in relation to another object in terms of its height. The work platform can also be formed by a frame or other support bodies which can be adjusted in height relative to the base frame. If necessary, the lifting device can be a component integrated into a larger device or machine which has the task of carrying out a lifting movement.The work platform can form a connecting element to which height-adjustable components can be attached. In this case, the work platform is intended to perform the height adjustment of this connected component.

[0016] At least one first stationary linear guide and one second stationary linear guide are fastened to the base frame. In the simplest embodiment, a single first stationary linear guide and a single second stationary linear guide may be sufficient. In a more developed embodiment, exactly two first stationary linear guides and exactly two second stationary linear guides can be fastened to the base frame. In such an embodiment, a first pair of a first stationary linear guide and a second stationary linear guide can be arranged on one lateral edge region of the lifting device or on one lateral edge region of the base frame and the work platform, and a second pair of a first stationary linear guide and a second stationary linear guide can be arranged on the opposite other lateral edge region of the lifting device orbe arranged on the opposite other lateral edge region of the base frame and the work platform. In an even more developed embodiment, for example, to accommodate very high loads, three or more pairs of first stationary linear guides and second stationary linear guides can be arranged on one lateral edge region of the lifting device or on one lateral edge region of the base frame and the work platform.

[0017] The respective first stationary linear guide rail is fastened to the base frame at an acute angle. This means that the first stationary linear guide rail with its longitudinal extension, which specifies the adjustment direction for the first sliding block element adjustably mounted on the first stationary linear guide rail, extends at an acute angle to the horizontal plane of the base frame. The respective first stationary linear guide rail is rigidly fastened to the base frame. The first stationary

[0018] The linear guide rail cannot move relative to the base frame or rotate or swivel relative to the base frame.

[0019] In the same way, each second stationary linear guide rail is attached to the base frame at an acute angle. This means that the longitudinal extent of the second stationary linear guide rail, which determines the adjustment direction for the second sliding block element adjustably mounted on the second stationary linear guide rail, extends at an acute angle to the horizontal plane of the base frame. Each second stationary linear guide rail is rigidly attached to the base frame. The second stationary linear guide rail cannot therefore move relative to the base frame, nor rotate or pivot relative to the base frame.

[0020] The size of the acute angle can in principle be freely selected. The acute angle can in particular be in the range between 5 and 45 degrees. The size of the acute angle determines the translation of the linear movement length of the respective sliding block element along the stationary linear guide rail in relation to the lifting height which the work platform executes when the sliding block elements are adjusted. The ratio of the linear movement length of the respective sliding block element along the stationary linear guide rail to the lifting height which the work platform executes when the sliding block elements are adjusted is linear over the entire adjustment path. This represents a particular advantage which the lifting device according to the invention has over the known designs of scissor lifting devices.In conventional scissor lifting devices, the angle of attack of the scissors changes continuously due to the design, with the scissors being in a very flat angular position in a low starting position and having to be pivoted out in order to be able to assume larger angular positions. This leads to extremely excessive drive forces in the drives of the scissor lifting devices, which are intended to move the scissors automatically in order to raise the lifting table, i.e. the work platform. For this reason, the drives in known scissor lifting devices must be relatively powerful in order to be able to move the scissors from the low starting position. Hydraulic drives are often provided for this reason, but these have the disadvantage that they require complex additional units and their size is relatively large, meaning that the overall size of the lifting device cannot be particularly flat.

[0021] However, the lifting device according to the invention is based on a different lifting principle, in which the lifting speed and the lifting forces behave linearly, so that even when the work platform is in a low position, particularly in its lowest position, the drive force remains constant at a constant lifting speed. This allows the use of less powerful drives, which are also more cost-effective and have a smaller overall size. As a result, a lifting device can be created that has a particularly low overall height in its low starting position.

[0022] A first stationary linear guide rail and a second stationary linear guide rail are always arranged in opposite directions with their acute-angled orientations. This means that, for example, the first stationary linear guide rail extends diagonally from an edge region of the base frame towards the center of the lifting device in an upward direction, and the second stationary linear guide rail extends diagonally from an opposite edge region of the base frame towards the center of the lifting device in an upward direction. The first stationary linear guide rail thus points upwards towards the second stationary linear guide rail. The first stationary linear guide rail and the second stationary linear guide rail preferably lie with their longitudinal extensions in the same vertical plane.The second stationary linear guide rail is accordingly arranged mirror-symmetrically to the first stationary linear guide rail.

[0023] In a modified embodiment, the first stationary linear guide rail can extend obliquely from a central region of the lifting device in the direction of an edge region of the base frame in an ascending orientation, and the second stationary linear guide rail can extend obliquely from a likewise central region of the lifting device in the direction of an opposite edge region of the base frame in an ascending orientation. The first stationary linear guide rail thus points upwards away from the second stationary linear guide rail. The first stationary linear guide rail and the second stationary linear guide rail likewise preferably lie with their longitudinal extents in the same vertical plane. In this case, too, the second stationary linear guide rail is arranged mirror-symmetrically to the first stationary linear guide rail.

[0024] The first lifting linear guide rail and the second lifting linear guide rail are connected to the work platform. The first lifting linear guide rail is arranged at an acute angle opposite to the first stationary linear guide rail. Similarly, the second lifting linear guide rail is arranged at an acute angle opposite to the second stationary linear guide rail.

[0025] The first sliding block element comprises the first sliding block body and the second sliding block body. The first sliding block body and the second sliding block body are connected to one another by the first sliding block element.

[0026] The second sliding block element comprises the third sliding block body and the fourth sliding block body. The third sliding block body and the fourth sliding block body are connected to each other by the second sliding block element.

[0027] In a design variant in which the first liftable linear guide rail and the second liftable linear guide rail are also rigidly connected to the work platform, the first sliding block body and the second sliding block body can also be rigidly connected to one another. If necessary, the first sliding block body and the second sliding block body can be manufactured as a one-piece first sliding block element. In the same way, the third sliding block body and the fourth sliding block body can also be rigidly connected to one another. If necessary, the third sliding block body and the fourth sliding block body can also be manufactured as a one-piece second sliding block element.

[0028] The lifting mobility of the first lifting-movable linear guide rail and the second lifting-movable linear guide rail results from the fact that the respective lifting-movable linear guide rail is rigidly connected to the work platform and thus raises or lowers with the work platform, or from the fact that at least the respective end section of the respective lifting-movable linear guide rail coupled to the work platform raises or lowers together with the work platform.

[0029] To raise or lower the work platform relative to the base frame, the at least one first sliding block element and the at least one second sliding block element are adjusted relative to one another in a horizontal plane. The horizontal plane extends parallel to the plane of the work platform or parallel to the plane of the base frame.

[0030] If the first stationary linear guide rail extends obliquely from an edge region of the base frame towards the center of the lifting device in an ascending direction and the second stationary linear guide rail extends obliquely from an opposite edge region of the base frame towards the center of the lifting device in an ascending direction, then the work platform is raised relative to the base frame by moving the first sliding block element and the second sliding block element towards each other. Accordingly, the work platform is lowered relative to the base frame by moving the first sliding block element and the second

[0031] Sliding block element can be moved away from each other.

[0032] If the first stationary linear guide rail extends obliquely from a central region of the lifting device towards an edge region of the base frame in an ascending orientation and the second stationary linear guide rail extends obliquely from a likewise central region of the lifting device towards an opposite edge region of the base frame in an ascending orientation, then the work platform is raised relative to the base frame by the first sliding block element and the second sliding block element being moved away from one another. Accordingly, the work platform is lowered relative to the base frame by the first sliding block element and the second sliding block element being moved towards one another.

[0033] The movement of the first sliding block element and the second sliding block element toward and away from each other can be carried out automatically by at least one drive device. In principle, electric drives, hydraulic drives, or pneumatic drives can be used for this purpose. Electric drives are particularly suitable for a very compact design with as few drive components as possible.

[0034] The respectively selected drive device can have a corresponding motor which generates a drive torque. The drive device can comprise a wide variety of joint couplings and / or gear types in order to convert the drive torque provided by the motor into a force couple which moves the first sliding block element and the second sliding block element in opposite directions. For example, the drive device can comprise a spindle which is driven by the drive torque of the motor and which transmits a respective linear axial force to the first sliding block element and the second sliding block element. However, the drive device can also comprise ropes, chains or belts which convert the drive torque of the motor into a respective linear movement of the first sliding block element and the second sliding block element.

[0035] The first stationary linear guide rail, the second stationary linear guide rail, the first linear guide rail with a lifting mechanism and / or the second linear guide rail with a lifting mechanism can each be formed by a respective profile guide rail which has an external guide surface and the respective corresponding first sliding block body, second sliding block body, third sliding block body and / or fourth sliding block body can be formed by a guide carriage running on the respective profile guide rail which has an internal counter-guide surface.

[0036] The respective profile guide rail can, for example, be a T-guide rail or a differently designed guide rail, for example with a C-shaped or a circular profile. The respective profile guide rail can be designed as a single rail or, for example, as a double rail with two profile bodies. A sliding film can be inserted between the respective profile guide rail and the respective corresponding first sliding block body, second sliding block body, third sliding block body and / or fourth sliding block body in order to keep the friction between the sliding pairs as low as possible.

[0037] Alternatively, the first stationary linear guide rail, the second stationary linear guide rail, the first linear guide rail with a lifting mechanism and / or the second linear guide rail with a lifting mechanism can each be formed by a respective profile-groove guide rail which has an internal guide surface and the respective corresponding first sliding block body, second sliding block body, third sliding block body and / or fourth sliding block body can be formed by a sliding block running in the respective profile-groove guide rail and which has an external counter-guide surface.

[0038] Here too, the respective profile guide rail can be, for example, a T-slot guide rail or a differently designed groove guide rail, for example with a C-shaped or a circular profile. The respective profile groove guide rail can be designed as a single rail or, for example, as a double rail with two profile bodies. A sliding film can be inserted between the respective profile groove guide rail and the respective corresponding first sliding block body, second sliding block body, third sliding block body and / or fourth sliding block body in order to keep the friction between the sliding pairs as low as possible.

[0039] The acute angle between the base frame and the first stationary linear guide rail, the acute angle between the base frame and the second stationary linear guide rail, the acute angle between the work platform and the first lifting linear guide rail, as well as the acute angle between the work platform and the second lifting linear guide rail can each be between 5 and 40 degrees, in particular between 10 and 20 degrees.

[0040] In the case of an embodiment in which the first lifting linear guide rail and the second lifting linear guide rail are rigidly attached to the work platform, the respective acute angles, not only of the stationary linear guide rails but also of the lifting linear guide rails, are always constant.

[0041] In an embodiment in which the first linear guide rail with a lifting action and the second linear guide rail with a lifting action are pivotally mounted on the work platform, only the acute angles of the stationary linear guide rails are constant. In this embodiment, the linear guide rails with a lifting action that are pivotally mounted on the work platform can also assume angles greater than 40 degrees.

[0042] The lifting device can have at least one drive device which is designed to automatically adjust the at least one first sliding block element and the at least one second sliding block element relative to one another.

[0043] The movement of the first sliding block element and the second sliding block element toward and away from each other can be carried out automatically by at least one drive device. In principle, electric drives, hydraulic drives, or pneumatic drives can be used for this purpose. Electric drives are particularly suitable for a very compact design with as few drive components as possible.

[0044] The respectively selected drive device can have a corresponding motor which generates a drive torque. The drive device can comprise a wide variety of joint couplings and / or gear types in order to convert the drive torque provided by the motor into a force couple which moves the first sliding block element and the second sliding block element in opposite directions. For example, the drive device can comprise a spindle which is driven by the drive torque of the motor and which transmits a respective linear axial force to the first sliding block element and the second sliding block element. However, the drive device can also comprise ropes, chains or belts which convert the drive torque of the motor into a respective linear movement of the first sliding block element and the second sliding block element.

[0045] The at least one drive device can be designed for synchronously adjusting the at least one first sliding block element and the at least one second sliding block element in opposite directions.

[0046] To ensure that the work platform remains in its horizontal alignment during raising and / or lowering and does not tip over in an undesired manner, and / or to ensure that the kinematics do not tilt or jam, the movements of the first sliding block element and the second sliding block element can be coupled. Such a coupling can be achieved, for example, mechanically via a corresponding coupling joint or via a gear. If the first sliding block element is moved by means of its own first drive and the second sliding block element is moved by means of its own second drive, the two drives can also be linked in terms of control technology, for example in the case of electric drives.

[0047] The drive device may comprise a motor and a spindle driven by the motor, which couples the first sliding block element to the second sliding block element in a manner that is adjustable relative to one another.

[0048] Such a motor-spindle unit can, for example, comprise an electric motor. In one specific embodiment, the spindle can be designed as an extension of the motor shaft. This means that the spindle does not adjust in its axial direction relative to the motor housing. In such a embodiment, the spindle can, for example, carry a spindle nut which can be adjusted linearly in the axial direction to the spindle by a rotary movement of the spindle driven by the motor. The spindle nut can, for example, be connected to the first sliding block element, or be formed in one piece with the first sliding block element and the motor housing can be connected to the second sliding block element.

[0049] In an alternative specific design variant, the spindle can be mounted axially adjustable within the motor housing. This means that when the motor shaft rotates, which in this case is designed as a hollow shaft in which the spindle runs, the spindle is adjusted in the axial direction relative to the motor housing. In this case, one end of the spindle can be rotatably coupled, for example, to the first sliding block element and the motor housing can be connected to the second

[0050] sliding block element.

[0051] The first lifting linear guide rail can be fastened to the work platform at a fixed acute angle and the second lifting linear guide rail can be fastened to the work platform at the same fixed acute angle in a mirror-symmetrical manner to the first lifting linear guide rail, wherein the first sliding block body and the second sliding block body are rigidly connected to one another to form the first sliding block element and the third sliding block body and the fourth sliding block body are rigidly connected to one another to form the second sliding block element.

[0052] A rigid connection of both the first stationary linear guide rail and the second stationary linear guide rail, as well as the first linear guide rail with a lifting mechanism and the second linear guide rail with a lifting mechanism, always ensures that the work platform is precisely aligned parallel to the base frame. If the base frame is set up on a horizontal plane, this also ensures that the work platform is always precisely aligned horizontally, i.e., at any adjustable lifting height.

[0053] At least one first drive device can be integrated into the first stationary linear guide rail and / or into the first linear guide rail with a lifting mechanism and can be designed for the driven adjustment of the first sliding block element and at least one second drive device can be integrated into the second stationary linear guide rail and / or into the second linear guide rail with a lifting mechanism and can be designed for the driven

[0054] Adjustment of the second sliding block element.

[0055] In such an embodiment, the first drive device and the second drive device can be linear drives. The respective linear drive can be an electric linear drive. The respective linear drive can be driven by means of spindles, belts, in particular toothed belts, or racks. The motor required for this can be an electric motor.

[0056] The at least one first linear drive and the at least one second linear drive can be coupled in terms of control technology, for example in the case of electric drives, so that the lifting movement on the first stationary linear guide rail and the first lifting-movable linear guide rail can be adapted to the lifting movement on the second stationary linear guide rail and the second lifting-movable linear guide rail, i.e. can be synchronized.

[0057] The first linear guide rail, which can be lifted, can be pivotally mounted on the work platform at an acute angle, and the second linear guide rail, which can be lifted, can be pivotally mounted on the work platform at an acute angle, mirror-symmetrically to the first linear guide rail, and / or the first sliding block body and the second sliding block body are pivotally connected to one another to form the first sliding block element, and the third sliding block body and the fourth sliding block body are pivotally connected to one another to form the second sliding block element. In such a specific development of the invention, the work platform can also be tilted in a targeted manner by differently adjusting the first sliding block element and the second sliding block element.Nevertheless, a purely horizontal lifting and lowering of the work platform can still be carried out by a synchronous movement of the first sliding block element and the second sliding block element.

[0058] Specific embodiments of the invention are explained in more detail in the following description with reference to the accompanying figures. Regardless of the specific context in which they are mentioned, specific features of these exemplary embodiments may, if appropriate, also represent general features of the invention when considered individually or in further combinations.

[0059] It shows :

[0060] Fig. 1 is a perspective view of a basic embodiment of a lifting device according to the invention,

[0061] Fig. 2 shows a first embodiment of a

[0062] Lifting device with rigidly mounted stationary and lifting linear guide rails in a raised configuration,

[0063] Fig . 3 the first embodiment of a

[0064] Lifting device according to Fig. 2 with rigidly mounted stationary and lifting linear guide rails in a lowered configuration,

[0065] Fig. 4 shows a second embodiment of a

[0066] Lifting device with rigidly mounted stationary and movable linear guide rails mounted on the work platform in an inclined raised configuration, and

[0067] Fig . 5 the second embodiment of a

[0068] Lifting device according to Fig. 4 with rigidly attached stationary and movable linear guide rails mounted on the work platform in a lowered configuration.

[0069] In Fig. 1 to Fig. 5 various embodiments of lifting devices 1 are shown.

[0070] The respective lifting device 1 serves to raise and lower a work platform 2 relative to a base frame 3, whereby a compact structure is created in a lowered state and the lifting device 1 is constructed from the simplest possible machine elements.

[0071] Fig. 1 shows a lifting device 1 for raising and lowering a work platform 2 relative to a base frame 3. The lifting device 1 has the base frame 3 and the work platform 2. The lifting device 1 comprises at least one first stationary linear guide rail 4. 1 fastened at an acute angle to the base frame 3 and at least one second stationary linear guide rail 4. 2 fastened at the same acute angle to the base frame 3 in mirror symmetry to the first stationary linear guide rail 4. 1.

[0072] In the case of the present embodiments, the lifting device 1 has exactly two first stationary linear guides

[0073] 4 . 1 and exactly two second stationary linear guides 4 . 2 . In such an embodiment, a first pair of a first stationary linear guide 4 . 1 and a second stationary linear guide 4 . 2 can be arranged on one lateral edge region of the lifting device 2 or on one lateral edge region of the base frame 3 and the work platform 2 and a second pair of a first stationary linear guide 4 . 1 and a second stationary linear guide

[0074] 4 .2 can be arranged on the opposite other lateral edge area of ​​the lifting device 1 or on the opposite other lateral edge area of ​​the base frame 3 and the work platform 2.

[0075] The lifting device 1 also comprises at least one first lifting-movable linear guide rail 5 . 1 connected to the work platform 2 at an opposite acute angle and at least one second lifting-movable linear guide rail 5 . 2 connected to the work platform 2 at an acute angle in mirror symmetry to the first lifting-movable linear guide rail 5 . 1.

[0076] In the case of the present embodiments, the lifting device 1 has exactly two first lifting linear guides 5.1 and exactly two second lifting linear guides 5.2. In such an embodiment, a first pair of a first lifting linear guide 5.1 and a second lifting linear guide 5.2 can be arranged on one lateral edge region of the lifting device 2 or on one lateral edge region of the base frame 3 and the work platform 2, and a second pair of a first lifting linear guide 5.1 and a second lifting linear guide 5.2 can be arranged on the opposite other lateral edge region of the lifting device 1 or on the opposite other lateral edge region of the base frame 3 and the work platform 2.

[0077] The lifting device 1 further comprises at least one first sliding block element 6.1, which has a first sliding block body 6a, which is mounted in a longitudinally adjustable manner on the first stationary linear guide rail 4.1, and which has a second sliding block body 6b, which is mounted in a longitudinally adjustable manner on the first lifting-movable linear guide rail 5.1.

[0078] The lifting device 1 also comprises at least one second sliding block element 6.2, which has a third sliding block body 6c, which is mounted in a longitudinally adjustable manner on the second stationary linear guide rail 4.2, and which has a fourth sliding block body 6d, which is mounted in a longitudinally adjustable manner on the second lifting-movable linear guide rail 5.2.

[0079] In the case of the present exemplary embodiments, the first stationary linear guide rail 4.1, the second stationary linear guide rail 4.2, the first linear guide rail with a movable stroke 5.1 and the second linear guide rail with a movable stroke 5.2 are formed by a respective profile guide rail which has an external guide surface, wherein the respectively corresponding first sliding block body 6a, the second sliding block body 6b, the third sliding block body 6c and the fourth sliding block body 6d are each formed by a guide carriage running on the respective profile guide rail, which guide carriage has an internal counter-guide surface.

[0080] However, the configuration of each guide rail arrangement could also be reversed.

[0081] Thus, the first stationary linear guide rail 4.1, the second stationary linear guide rail 4.2, the first linear guide rail with a lifting capacity 5.1 and the second linear guide rail with a lifting capacity 5.2 could be formed by a respective profile-groove guide rail which has an internal guide surface, wherein the respective corresponding first sliding block body 6a, the second sliding block body 6b, the third sliding block body 6c and the fourth sliding block body 6d are formed by a sliding block running in the respective profile-groove guide rail and which has an external counter-guide surface.

[0082] The acute angle between the base frame 3 and the first stationary linear guide rail 4.1, the acute angle between the base frame 3 and the second stationary linear guide rail 4.2, the acute angle between the work platform 2 and the first liftable linear guide rail 5.1, and the acute angle between the work platform 2 and the second liftable linear guide rail 5.2 can each be between 5 and 40 degrees, in particular between 10 and 20 degrees. In the case of the illustrated embodiments, the respective acute angle is approximately 13 degrees. The size of the acute angle determines the translation of the linear movement length of the respective sliding block element 6.1, 6.2 along the stationary linear guide rail 4.1, 4.2 in relation to the lifting height which the work platform 2 executes when the sliding block elements 6.1, 6.2 are adjusted. The ratio of the linear movement length of the respective sliding block element 6.1, 6.2 along the stationary linear guide rail 4.1, 4.2 to the lifting height, which the work platform 2 achieves when adjusting the sliding block elements 6.1, 6.2, is linear over the entire adjustment path. This represents a particular advantage that the lifting device 1 according to the invention has over known designs of scissor lifting devices.

[0083] The lifting devices 1 according to the invention are thus based on a different lifting principle, in which the lifting speed and the lifting forces behave linearly, so that even in a low position of the work platform 2, in particular even in the lowest position of the work platform 2, the drive force remains constant at a constant lifting speed. This allows the use of less powerful drives, which are also more cost-effective and have a smaller overall size. As a result, a lifting device 1 can be created that has a particularly low overall height in its low starting position.

[0084] The lifting device 1 has at least one drive device 7, which is designed to automatically adjust the at least one first sliding block element 6.1 and the at least one second sliding block element 6.2 relative to one another. The at least one drive device 7 can be designed to synchronously adjust the at least one first sliding block element 6.1 and the at least one second sliding block element 6.2 in opposite directions.

[0085] In the illustrated embodiments, the drive device 7 comprises a motor 8 and a spindle 9 driven by the motor 8, which couples the first sliding block element 6.1 to the second sliding block element 6.2 in a manner that is adjustable relative to one another.

[0086] In the embodiment according to Fig. 2 and Fig. 3, the first lifting linear guide rail 5.1 is fastened to the work platform 2 at a fixed acute angle and the second lifting linear guide rail 5.2 is fastened to the work platform 2 at the same fixed acute angle in a mirror-symmetrical manner to the first lifting linear guide rail 5.1, wherein the first sliding block body 6a and the second sliding block body 6b are rigidly connected to one another to form the first sliding block element 6.1 and the third sliding block body 6c and the fourth sliding block body 6d are rigidly connected to one another to form the second sliding block element 6.1.

[0087] Instead of a single separate drive device 7, as shown in Fig. 2, at least one first drive device 7.1 can be integrated into the first stationary linear guide rail 4.1 and / or into the first linear guide rail 5.1 with a travel range of up to 100 mm and can be designed for the driven adjustment of the first sliding block element 6.1, or of the first sliding block body 6a and / or of the second sliding block body 6b, and at least one second drive device 7.2 can be integrated into the second stationary linear guide rail 4.2 and / or into the second linear guide rail 5.2 with a travel range of up to 100 mm and can be designed for the driven adjustment of the second sliding block element 6.2.

[0088] Such separate first drive devices 7.1 and second drive devices 7.2 can be used in the modified

[0089] Embodiment according to Fig. 4 and Fig. 5 may be appropriate.

[0090] The first lifting linear guide rail 5.1 can be pivotally mounted on the work platform 2 at an acute angle by means of a first pivot bearing 10.1 and the second lifting linear guide rail 5.2 can be pivotally mounted on the work platform 2 at an acute angle in mirror symmetry to the first lifting linear guide rail 5.1 by means of a second pivot bearing 10.2.

Claims

Patent claims 1. Lifting device for raising and lowering a work platform (2) relative to a base frame (3), comprising: - a base frame (3) , - a work platform (2) , - at least one first stationary linear guide rail (4.1) fastened to the base frame (3) at an acute angle and at least one second stationary linear guide rail (4.2) fastened to the base frame (3) at the same acute angle and mirror-symmetrically to the first stationary linear guide rail (4.1), - at least one first lifting-movable linear guide rail (5.1) connected to the work platform (2) at an opposite acute angle and at least one second lifting-movable linear guide rail (5.2) connected to the work platform (2) at an acute angle mirror-symmetrically to the first lifting-movable linear guide rail (5.1), and - at least one first sliding block element (6.1) which has a first sliding block body (6a) which is mounted on the first stationary linear guide rail (4.1) in a longitudinally adjustable manner and has a second sliding block body (6b) which is mounted on the first linear guide rail (5.1) is mounted in a longitudinally adjustable manner, and - at least one second sliding block element (6.2) which has a third sliding block body (6c) which is mounted in a longitudinally adjustable manner on the second stationary linear guide rail (4.2) and has a fourth sliding block body (6d) which is mounted in a longitudinally adjustable manner on the second linear guide rail (5.2) which is movable in a lifting manner.

2. Lifting device according to claim 1, characterized in that the first stationary linear guide rail (4.1), the second stationary linear guide rail (4.2), the first linear guide rail with a lifting motion (5.1) and / or the second linear guide rail with a lifting motion (5.2) is formed by a respective profile guide rail which has an external guide surface and the respectively corresponding first sliding block body (6a), second sliding block body (6b), third sliding block body (6c) and / or fourth sliding block body (6d) is formed by a guide carriage running on the respective profile guide rail, which guide carriage has an internal counter-guide surface.

3. Lifting device according to claim 1, characterized in that the first stationary linear guide rail (4.1), the second stationary linear guide rail (4.2), the first linear guide rail (5.1) which can be lifted and / or the second linear guide rail (5.2) which can be lifted and / or is formed by a respective profile-groove guide rail which has an internal guide surface and the respective corresponding first sliding block body (6a), second sliding block bodies (6b), third sliding block bodies (6c) and / or fourth sliding block bodies (6d) of a profile in the respective Groove guide rail running sliding block is formed, which has an external counter-guide surface.

4. Lifting device according to one of claims 1 to 3, characterized in that the acute angle between the base frame (3) and the first stationary linear guide rail (4.1), the acute angle between the base frame (3) and the second stationary linear guide rail (4.2), the acute angle between the work platform (2) and the first lifting-movable linear guide rail (5.1), and the acute angle between the work platform (2) and the second lifting-movable linear guide rail (5.2) are each between 5 and 40 degrees, in particular between 10 and 20 degrees.

5. Lifting device according to one of claims 1 to 4, characterized in that the lifting device (1) has at least one drive device (7) which is designed for the automatic adjustment of the at least one first sliding block element (6.1) and the at least one second sliding block element (6.2) relative to one another.

6. Lifting device according to claim 5, characterized in that the at least one drive device (7) is designed for synchronously adjusting the at least one first sliding block element (6.1) and the at least one second sliding block element (6.2) in opposite directions.

7. Lifting device according to one of claims 5 to 7, characterized in that the drive device (7) comprises a motor (8) and a spindle (9) driven by the motor (8), which couples the first sliding block element (6.1) to the second sliding block element (6.2) in a manner that is adjustable relative to one another.

8. Lifting device according to one of claims 1 to 7, characterized in that the first lifting-movable linear guide rail (5.1) is fastened to the work platform (2) at a fixed acute angle and the second lifting-movable linear guide rail (5.2) is fastened to the work platform (2) at the same fixed acute angle in a mirror-symmetrical manner to the first lifting-movable linear guide rail (5.1), wherein the first sliding block body (6a) and the second sliding block body (6b) are rigidly connected to one another to form the first sliding block element (6.1) and the third sliding block body (6c) and the fourth sliding block body (6d) are rigidly connected to one another to form the second sliding block element (6.2).

9. Lifting device according to one of claims 1 to 8, characterized in that at least one first drive device (7.1) is integrated into the first stationary linear guide rail (4.1) and / or into the first linear guide rail (5.1) capable of being lifted and is designed for the driven adjustment of the first sliding block element (6.1) and at least one second drive device (7.2) is integrated into the second stationary linear guide rail (4.2) and / or into the second linear guide rail (5.2) capable of being lifted is integrated and is designed for the driven adjustment of the second sliding block element (6.2).

10. Lifting device according to claim 9, characterized in that the first linear guide rail (5.1) is pivotable at an acute angle on the Working platform (2) is mounted and the second lifting linear guide rail (5.2) is pivotally mounted on the working platform (2) at an acute angle mirror-symmetrically to the first lifting linear guide rail (5.1), and / or the first sliding block body (6a) and the second sliding block body (6b) are pivotally connected to one another to form the first sliding block element (6.1) and the third sliding block body (6c) and the fourth sliding block body (6d) are pivotally connected to form the second Sliding block element (6.2) are pivotally connected to each other.

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