Product tray for storing divided machined product of plate-shaped workpiece, and mechanical device having such product tray

Abstract

A product tray (1) is used for storing workpiece parts existing as machined products of split machining of plate-shaped workpieces and remaining grilles existing as other machined products of split machining of the workpieces. The product tray is provided with a bearing element (5) which is arranged on the side of the processed product and is used for bearing the workpiece part and the residual grid together in the gravity direction. In a first functional state of the product tray (1), the workpiece part and the remaining grid can be jointly supported in the direction of gravity by means of the bearing elements (5) of the product tray (1). In the second functional state, the product tray (1) forms a flat bearing surface (7) on the upper side of the product tray for supporting only workpiece components in the gravitational direction. A machine arrangement for treating workpiece parts present as machined products of split machining of plate-shaped workpieces and remaining grilles present as further machined products of split machining of workpieces, comprising a product tray (1) of the above type.

Description

Technical Field

[0001] This utility model relates to a product tray for storing workpiece parts that are processed products of segmented processing of plate-shaped workpieces (especially sheet metal) and remaining grids that are other processed products of segmented workpiece processing. In particular, it is a detachable product assembly for storing workpiece parts and remaining grids.

[0002] • The product tray has a supporting element, which is configured on the side where the product is being processed to jointly support the workpiece components and the remaining grid in the direction of gravity.

[0003] • The product tray can be switched to a first functional state and a second functional state. In the first functional state of the product tray, the workpiece components and the remaining grid can be supported together along the direction of gravity by means of the support elements of the product tray.

[0004] This utility model also relates to a mechanical device for processing workpiece parts that exist as processed products of segmented processing of plate-shaped workpieces (especially sheet metal) and residual grids that exist as other processed products of segmented workpiece processing, particularly for processing detachable product assemblies of workpiece parts and residual grids, wherein the mechanical device has a product tray of the type described above for storing workpiece parts and residual grids. Background Technology

[0005] Such prior art is disclosed in EP 4 257 285 A1.

[0006] In the prior art, sheet metal supported on a pallet is processed in segments on a laser cutting machine. Here, multiple sheet metal components and the remaining grid surrounding the sheet metal components are produced as processed products. Similar to the sheet metal during segmented processing, the processed products are immediately supported on the support strips of the pallet after the segmented sheet metal processing. The support strips are securely mounted to the pallet frame.

[0007] A pallet carrying the processed products moves from the working area of ​​the laser cutting machine to the unloading station. At the unloading station, the sheet metal components and remaining grids are lifted together from the support bars by means of a lifting device. For this purpose, the lifting device has upwardly projecting lifting elements mounted on a base plate arranged below the pallet. These lifting elements move upward through the intermediate space between the support bars of the pallet due to the lifting movement of the base plate. The lifting elements here rest their front ends against the underside of the processed products supported on the support bars, and as the lifting movement continues, they remove the processed products from the support bars. The remaining grids, removed from the pallet's support bars, are gripped by a gripping device and stored on a remaining grid tray. Then, the sheet metal components, also removed from the pallet's support bars, are received and transported to the sheet metal component tray by means of a suction frame provided for this purpose. Utility Model Content

[0008] The objective of this invention is to provide a mechanical device for processing plate-shaped workpieces in a segmented manner, where the processed products exist in the form of workpiece parts and remaining grids. In this mechanical device, the same product tray can be used for both the common storage of processed products and the smooth and orderly storage of workpiece parts separated from the remaining grids.

[0009] According to this utility model, the above task is solved by a product tray according to this utility model and a mechanical device equipped with such a product tray according to this utility model.

[0010] The product tray according to this utility model can be switched to two functional states.

[0011] In its first functional state, the product tray, like existing trays, is used to jointly support processed products from segmented workpiece machining, particularly segmented sheet metal machining. The workpiece from the segmented workpiece machining process and any remaining grid can be supported together on the support elements of the product tray, preferably conventional support strips. In this functional state, the product tray according to this invention is, for example, immediately following the segmented workpiece machining process.

[0012] After the workpiece components are separated from the remaining grid, the product tray according to this invention is transferred to a second functional state. In the second functional state of the product tray, the upper side of the product tray is constructed with a flat supporting surface, which enables the workpiece components separated from the remaining grid to be stored in a particularly smooth and orderly manner.

[0013] The specific implementation scheme of this utility model is obtained from the following description.

[0014] Another embodiment relates to the feasibility of achieving a preferred first functional state and a second functional state of the product tray according to the present invention. In this case, the product tray according to the present invention has an element unit provided with a supporting element and a surface unit provided with a supporting surface. The two units of the product tray can be selectively adjusted relative to each other in a first relative position or a second relative position in the vertical direction. In the first functional state of the product tray, and in the first relative position of the element unit and surface unit associated with the first functional state of the product tray, the supporting element protrudes upward relative to the supporting surface on the side of the processed product. In the second functional state of the product tray, and in the second relative position of the element unit and surface unit associated with the second functional state of the product tray, the supporting element is arranged flush with the supporting surface or offset downward relative to the supporting surface on the side of the processed product.

[0015] In another embodiment of the product tray according to the present invention, the component unit of the product tray has a base on which a supporting element is disposed and protrudes upward. The base of the component unit is arranged below the supporting surface of the surface unit. The surface unit has a through-hole on its supporting surface, through which the supporting element of the component unit moves when the relative position of the component unit and the surface unit changes and the functional state of the product tray changes accordingly.

[0016] According to another embodiment, in a preferred configuration of the product tray according to the present invention, the element units and surface units of the product tray respectively construct two opposing frame legs of the rectangular tray frame of the product tray. Therefore, the tray frame of the product tray according to the present invention consists of two pairs of frame legs, which, as part of the element units and surface units, can be adjusted relative to each other in the vertical direction.

[0017] In another configuration of the product pallet according to the present invention, at least one of the frame legs of the pallet frame is provided with a guide device, by means of which the product pallet is guided as it moves in the longitudinal direction of the frame legs of the frame leg pair provided with the guide device. For example, the guide device may be a guide device with guide rollers, which work together with the associated guide rail during the movement of the product pallet.

[0018] In another embodiment of the utility model, each of the two frame leg pairs of the product tray according to the present utility model has a guide device of the type described above. These two guide devices enable the product tray to be guided in the longitudinal direction of the two frame leg pairs extending perpendicularly to each other within the rectangular tray frame. Here, a guide device on one frame leg pair can be used in the first relative position of the element unit and the surface unit, and thus in the first functional state of the product tray. A guide device on the other frame leg pair can be provided in the second relative position of the element unit and the surface unit, and thus in the second functional state of the product tray.

[0019] Since the processed products are supported on a support element that protrudes upward relative to the flat support surface of the product tray in the first functional state, the processed products can be easily unloaded from the product tray. The unloading unit of the machine device according to another embodiment of the present invention is used in this case.

[0020] In addition to the unloading unit, the mechanical device according to another embodiment of the present invention also includes a separation unit and a loading unit. By means of the separation unit, after unloading the workpiece components and the remaining grid from the product tray in the first functional state, the workpiece components are separated from the remaining grid. Then, the workpiece components separated from the remaining grid are stored on the product tray by means of the loading unit, which has previously been transferred from the first functional state to the second functional state, and thus provides a flat supporting surface suitable for the smooth and orderly storage of the workpiece components.

[0021] In another embodiment of the mechanical device according to the present invention, in addition to separating the workpiece component from the remaining grid, the separation unit is also used to unload the processed product from the product tray in the first functional state and / or to load the workpiece component separated from the remaining grid onto the product tray in the second functional state.

[0022] Another embodiment relates to another preferred structural form of the mechanical device according to the present invention. Here, the separation unit forms a compact structural unit that can be used both to unload the workpiece and the remaining grid from the product tray in the first functional state, and to separate the workpiece components from the remaining grid and store the workpiece components separated from the remaining grid on the product tray transferred to the second functional state.

[0023] According to another embodiment, in another preferred configuration of the machine device according to the present invention, a lifting device is provided for adjusting the component units and surface units of the product tray according to the present invention to a first relative position and a second relative position, thereby transferring the product tray according to the present invention to a first functional state and a second functional state. With the aid of the lifting device, the component units and surface units of the product tray can be adjusted relative to each other in the vertical direction.

[0024] Another embodiment relates to the structural form of the mechanical device according to the present invention, wherein the component units and surface units of the product tray according to the present invention are adjusted to a first relative position and a second relative position, thereby enabling the product tray according to the present invention to be transferred to a first functional state and a second functional state using the above-mentioned lifting device with structurally simple measures. Attached Figure Description

[0025] The present invention will now be explained in more detail with the aid of exemplary schematic diagrams. These diagrams show:

[0026] Figure 1 Product trays are used when handling processed products from segmented sheet metal processing in their first functional state.

[0027] Figure 2according to Figure 1 The product tray is in the second functional state.

[0028] Figure 3 according to Figure 2 Product trays in Figure 2 The sectional view in section III is shown.

[0029] Figure 4 The mechanical separation station is used to process products from segmented sheet metal processing, and has the capability to... Figures 1 to 3 Product pallets loaded with processed products,

[0030] Figure 5 Along Figure 4 According to the direction of the middle arrow V in the vertical view Figure 4 The separation station, and

[0031] Figures 6 to 10 From the basis Figure 4 and Figure 5 Based on the conditions, according to Figure 4 and Figure 5 The process at the separation station. Detailed Implementation

[0032] The product tray 1 shown in the attached figure includes component unit 2 and surface unit 3.

[0033] The component unit 2 of the product tray 1 has a base plate 4 serving as a base, on which the supporting element (constructed as a support strip 5) of the component unit 2 protrudes upward. With the help of the base plate 4, the component unit 2 is located below the support plate 6 of the surface unit 3 of the product tray 1. The support plate 6 has a support surface 7 on its upper side and a through-hole 8 for the support strip 5 of the component unit 2 is provided on the support surface 7.

[0034] The rectangular pallet frame 9 of the product pallet 1 includes two frame leg pairs 10 and 11, wherein frame leg pair 10 is part of element unit 2, and frame leg pair 11 is part of surface unit 3.

[0035] Each of the frame legs 12 of the frame leg pair 10 of component unit 2 is provided with a guide device in the form of a guide roller 14. The guide roller 14 guides the product tray 1 during movement along the longitudinal direction of the frame leg 12 of component unit 2. Correspondingly, the frame legs 13 of the frame leg pair 11 of surface unit 3 are provided with... Figure 1 and Figure 2 The covered guide roller 15 serves as a guiding device. Figures 5 to 9 With the aid of guide rollers 15, the product tray 1 is guided as it moves in the longitudinal direction along the frame leg 13 of the surface unit 3.

[0036] The component unit 2 and surface unit 3 of the product tray 1 can be adjusted relative to each other in the vertical direction. As a result, the product tray 1 can be switched between the first functional state and the second functional state.

[0037] exist Figure 1 In the first functional state shown and existing when element unit 2 and surface unit 3 are in the first relative position, product tray 1 is used to support workpiece parts in the form of sheet metal parts 16 generated during the split sheet metal processing, and the remaining grid 17 generated as another processed product in the split sheet metal processing, by means of the support strip 5 protruding upward relative to the support surface 7 of product tray 1, in the direction of gravity. Figure 9 , 10 ).

[0038] From Figure 2 In the visible second functional state, and in the associated second relative position of component unit 2 and surface unit 3, the support strip 5 of component unit 2 does not protrude upward relative to the support plate 6 of surface unit 2 on the product side. Therefore, the product tray 1 has a flat support surface 7 constructed on its upper side, which, as described below, is used to support only the sheet metal component 16 in the direction of gravity.

[0039] Figures 4 to 10 The image shows the product pallet 1 as part of a mechanical device 18, used to handle the sheet metal component 16 and the remaining grid 17.

[0040] Sheet metal component 16 and remaining grid 17 are produced by slicing the sheet metal on a laser cutting machine (not shown). In the workspace of the laser cutting machine, the sheet metal is supported on a product tray 1 during the slicing process. After the slicing process is completed, the product tray 1 containing sheet metal component 16 and remaining grid 17 is removed from the workspace of the laser cutting machine and transported to the separation station 19 of the mechanical device 18.

[0041] Figure 4 and Figure 5 The image shows the product pallet 1, loaded with sheet metal component 16 and remaining grid 17, arriving at separation station 19.

[0042] In segmented sheet metal processing, a nanometer-scale connection is left between the sheet metal component 16 and the remaining grid 17. Therefore, Figure 4 and Figure 5 The sheet metal component 16 and the remaining grille 17 form a detachable product assembly 20.

[0043] During its journey to the separation station 19, the product tray 1 is guided on the guide rail 21 by means of the guide roller 14 of the component unit 2, which extends all the way to the separation station 19.

[0044] Since the sheet metal is processed on the laser cutting machine, product tray 1 has been in its primary functional state. Correspondingly, component unit 2 and surface unit 3 are... Figure 4 and Figure 5 It occupies the first relative position.

[0045] Figure 4 and Figure 5 As shown, there is a separation unit 22 above the product tray 1 containing the product assembly 20.

[0046] The separation unit 22 is provided with a holding device 23. The holding device 23 has a gripper 24, which remains in its initial position after the product tray 1 loaded with the product assembly 20 is moved into the separation station 19. The gripper is arranged outside the product assembly 20 along the vertical projection of the plane of the product assembly 20.

[0047] Based on these conditions, the gripper 24 of the holding device 23 is adjusted to a position in which the gripper grasps the product assembly 20 at the remaining grid 17. Figure 6 ).

[0048] exist Figures 4 to 6 In this configuration, the guide rollers 14 of the frame legs 10 of the product tray 1 and component unit 2 are supported by gravity on the horizontal support member 25 of the lifting device 26, which is aligned with the guide rail 21. The horizontal support member 25 of the lifting device 26 can be raised and lowered by a motor driven on the support frame 27 of the separation station 19.

[0049] exist Figures 4 to 6 In this configuration, the surface unit 3 of the product tray 1 is supported on the base plate 4 of the component unit 2 along the direction of gravity. Here, the frame legs 13 of the surface unit 3 and the guide rollers 15 disposed thereon are spaced apart in the vertical direction from the support member 28 fixedly mounted on the support frame 27 of the separation station 19.

[0050] according to Figure 6 As shown, the product tray 1, which contains the product assembly 20, and the separation unit 22 are lowered together by means of the lifting device 26.

[0051] During the descent, the product tray 1 is placed on the support member 28 on the support frame 27 by means of the guide rollers 15 set on the frame legs 13 of the surface unit 3.

[0052] As the product tray 1 continues its downward movement, the component unit 2 of the product tray 1 moves downward relative to the surface unit 3, which is now fixedly supported in the direction of gravity. This creates a second relative position between the component unit 2 and the surface unit 3, resulting in a second functional state of the associated product tray 1, in which a flat supporting surface 7 is constructed on the upper side of the product tray 1. Figure 7 , Figure 8 ).

[0053] The guide rollers 14 on the frame leg 12 of component unit 2 are now positioned at a distance above the horizontal support 25 of the lifting device 26. Component unit 2, together with the substrate 4, is supported on the surface unit 3 by a stop 29 provided for this purpose along the direction of gravity. Figure 3 ).

[0054] When necessary, the first relative position of the element unit 2 and the surface unit 3 can be restored by lifting the element unit 2 relative to the surface unit 3 supported on the support member 28.

[0055] During the descent of the product tray 1, the product assembly 20 is pulled to the underside of the vibrating plate 30 of the separation unit 22 by means of the holding device 23. A vibrator 31, acting as a vibration generator, is positioned above the vibrating plate 30 and causes the vibrating plate 30 to vibrate vertically after the product tray 1 is transferred to the second functional state. Due to the vibration of the vibrating plate 30, the sheet material component 16 detaches from the remaining grid 17, which is also secured to the separation unit 22 by means of the holding device 23. Under the influence of gravity, the sheet material component 16, separated from the remaining grid 17, lies smoothly and orderly on the flat storage surface 7 of the product tray 1. Figure 9 ).

[0056] The guide rail 32, located outside the separation station 19, is aligned with the support member 28 on the support frame 27 of the separation station 19. The product pallet 1, now loaded only with the sheet metal component 16, is moved out of the separation station 19 via the guide rail 32. Here, the product pallet 1 is guided on the guide rail 32 by means of guide rollers 15 provided on the frame legs 13 of the surface unit 3.

[0057] The remaining grille 17 fixed to the separation unit 22 is removed separately from the separation station 19.

Claims

1. A product tray for storing workpiece parts (16) existing as processed products of segmented machining of plate-shaped workpieces and remaining grids (17) existing as other processed products of segmented workpiece machining. ·in, The product tray has a support element (5) configured on the side of the processed product to jointly support the workpiece component (16) and the remaining grid (17) in the direction of gravity, and • The product tray can be switched between a first functional state and a second functional state. In the first functional state of the product tray, the workpiece component (16) and the remaining grid (17) can be supported together along the direction of gravity by means of the supporting element (5) of the product tray. The product tray is characterized in that, in the second functional state, the product tray has a support surface (7) on its upper side that is adapted to uniquely support the workpiece component (16) in the direction of gravity.

2. The product tray according to claim 1, characterized in that, The product tray is designed to store workpiece components (16) that are processed products as sheet metal and remaining grids (17) that are other processed products as sheet metal.

3. The product tray according to claim 1 or claim 2, characterized in that, The product tray is configured to hold the detachable product assembly (20) of the workpiece component (16) and the remaining grille (17).

4. The product tray according to claim 1 or claim 2, characterized in that, The product tray can be switched between the first functional state and the second functional state in that the product tray has a component unit (2) provided with the supporting element (5) and a surface unit (3) provided with the supporting surface (7), and the component unit (2) and the surface unit (3) of the product tray can be adjusted relative to each other in the vertical direction. • In the first functional state of the product tray, the component unit (2) and the surface unit (3) of the product tray are vertically adjusted to a first relative position relative to each other. In the first relative position, the supporting element (5) of the component unit (2) protrudes upward relative to the supporting surface (7) of the surface unit (3) on the side of the processed product. • In the second functional state of the product tray, the component unit (2) and the surface unit (3) of the product tray are adjusted to a second relative position relative to each other in the vertical direction. In the second relative position, the supporting element (5) of the component unit (2) does not protrude upward relative to the supporting surface (7) of the surface unit (3) on the side of the processed product.

5. The product tray according to claim 4, characterized in that, The component unit (2) of the product tray has a base (4), and the supporting component (5) is disposed on the base and protrudes upward. • The component unit (2) is arranged with its base (4) below the supporting surface (7) of the surface unit (3) of the product tray, and • The surface unit (3) has an opening (8) on the supporting surface (7) for the supporting element (5) of the element unit (2).

6. The product tray according to claim 4, characterized in that, The product pallet has a rectangular pallet frame (9), the pallet frame having two pairs of frame legs (10, 11), each pair of frame legs comprising two opposing frame legs (12, 13), and • One pair of frame legs (10) is constructed from the element unit (2) of the product tray, while the other pair of frame legs (11) is constructed from the surface unit (3) of the product tray.

7. The product tray according to claim 6, characterized in that, At least one of the frame leg pairs (10, 11), the frame leg (12, 13) is provided with a guide device (14, 15) for guiding the product tray when moving along the longitudinal direction of the frame leg (12, 13) provided with the guide device (14, 15).

8. The product tray according to claim 7, characterized in that, Each of the frame leg pairs (10, 11) is provided with a guide device (14, 15), and In the first relative position of the element unit (2) and the surface unit (3), the guide device (14, 15) can engage with one frame leg pair (10, 11), and in the second relative position of the element unit (2) and the surface unit (3), the guide device (14, 15) can engage with another frame leg pair (10, 11) for guiding the product tray.

9. A mechanical device for processing a workpiece component (16) existing as a processed product of segmented machining of a plate-shaped workpiece and a remaining grid (17) existing as another processed product of segmented workpiece machining, wherein, The mechanical device has a product tray (1) for storing the workpiece component (16) and the remaining grille (17). The product is characterized by having a product tray (1) according to any one of claims 1 to 8 as the product tray (1).

10. The mechanical device according to claim 9, characterized in that, The mechanical device is configured to process a workpiece component (16) existing as a processed product of sheet metal segmentation and a remaining grid (17) existing as another processed product of sheet metal segmentation.

11. The mechanical device according to claim 9, characterized in that, The mechanical device is configured as a detachable product assembly (20) for handling the workpiece component (16) and the remaining grille (17).

12. The mechanical device according to claim 9, characterized in that, The mechanical device has an unloading unit by means of which the workpiece component (16) and the remaining grille (17) can be unloaded from the product tray (1) transferred to the first functional state.

13. The mechanical device according to claim 12, characterized in that, The mechanical device has a separation unit (22) and a loading unit. • After unloading the product tray (1), the workpiece component (16) can be separated from the remaining grille (17) by means of the separation unit (22), and • The product tray (1) transferred to the second functional state can be loaded with the workpiece component (16) separated from the remaining grid (17) by means of the loading unit.

14. The mechanical device according to claim 13, characterized in that, The separation unit (22) constructs the unloading unit for unloading the product tray (1) in the first functional state. The method is that the separation unit (22) is provided with a holding device (23), by means of which the processed product supported on the product tray (1) in the first functional state can be fixed on the separation unit (22), and • In this way, the processed product fixed on the holding device (23) can be unloaded by the supporting element (5) of the product tray (1) in the first functional state.

15. The mechanical device according to claim 13 or 14, characterized in that, The separation unit (22) constitutes the loading unit for loading the product tray (1) located in the second functional state. The method is such that the separation unit (22) with the workpiece component (16) separated from the remaining grille (17) and the product tray (1) in the second functional state can be arranged relative to each other such that the product tray (1) in the second functional state is arranged below the workpiece component (16), and • In this manner, the workpiece component (16) can be released from the separation unit (22) for storage on the product tray (1) in the second functional state.

16. The mechanical device according to claim 13, characterized in that: The mechanical device is configured to handle the detachable product assembly (20) of the workpiece component (16) and the remaining grille (17). The separation unit (22) constitutes the unloading unit for unloading the product tray (1) in the first functional state. - In this manner, the separating unit (22) is provided with a holding device (23), by means of which the processed product supported on the product tray (1) in the first functional state can be fixed on the separating unit (22), in such a way that the product assembly (20) supported on the product tray (1) in the first functional state can be fixed on the holding device (23) of the separating unit (22), and - In this manner, the processed product fixed to the holding device (23) can be unloaded by the supporting element (5) of the product tray (1) in the first functional state, and the product assembly (20) fixed to the holding device (23) can be unloaded by the supporting element (5) of the product tray (1) in the first functional state, and • The separation unit (22) has a vibration generator (31) by means of which vertical vibration of the holding device (23) is generated, which causes the workpiece component (16) to detach from the product assembly (20).

17. The mechanical device according to any one of claims 9 to 14, characterized in that, ·in, The product tray can be switched between the first functional state and the second functional state in that the product tray has a component unit (2) provided with the supporting element (5) and a surface unit (3) provided with the supporting surface (7), and the component unit (2) and the surface unit (3) of the product tray can be adjusted relative to each other in the vertical direction. • In the first functional state of the product tray, the component unit (2) and the surface unit (3) of the product tray are vertically adjusted to a first relative position relative to each other. In the first relative position, the supporting element (5) of the component unit (2) protrudes upward relative to the supporting surface (7) of the surface unit (3) on the side of the processed product. • In the second functional state of the product tray, the component unit (2) and the surface unit (3) of the product tray are adjusted to a second relative position relative to each other in the vertical direction. In the second relative position, the supporting element (5) of the component unit (2) does not protrude upward relative to the supporting surface (7) of the surface unit (3) on the side of the processed product. The mechanical device has a lifting device (26) by means of which the component units (2) of the product tray (1) and the surface units (3) of the product tray (1) can be adjusted relative to each other in a first relative position and / or a second relative position in the vertical direction.

18. The mechanical device according to claim 17, characterized in that, In the first relative position of the element unit (2) and the surface unit (3), the surface unit (3) is supported on the element unit (2) along the direction of gravity, and • In order to adjust the element unit (2) and the surface unit (3) from the first relative position to the second relative position - The lifting device (26) for the component unit (2) and the support member (28) for the surface unit (3) acting in the direction of gravity are provided, and - The element unit (2) can be lowered relative to the surface unit (3) supported on the support member (28) in the direction of gravity by means of the lifting device (26).

19. The mechanical device according to claim 18, characterized in that, A stop (29) for the element unit (2) is provided on the surface unit (3), and the stop acts in the vertical direction in the second relative position of the element unit (2) and the surface unit (3).

20. The mechanical device according to claim 17, characterized in that, In order to adjust the element unit (2) and the surface unit (3) from the second relative position to the first relative position, • The lifting device (26) for the component unit (2) and the support member (28) for the surface unit (3) acting in the direction of gravity are provided. • The element unit (2) can be lifted relative to the surface unit (3) supported on the support member (28) in the direction of gravity by means of the lifting device (26).

Images