EP2427402B1

EP2427402B1 - Lifting device and lifting element for use in a lifting device

Info

Publication number: EP2427402B1
Application number: EP10713267A
Authority: EP
Inventors: Ronaldus Petrus Theodorus Maria Maas
Original assignee: Slemaco Beheer BV
Current assignee: Slemaco Beheer BV
Priority date: 2009-05-08
Filing date: 2010-04-15
Publication date: 2013-03-20
Anticipated expiration: 2030-04-15
Also published as: EP2427402A1; WO2010128847A1; NL1036935C2

Description

The present invention, according to a first aspect thereof, relates to a lifting device comprising a base, an elongate arm, which is pivotally connected to the base with a first end for movement about a horizontal first axis, an elongate mast, which is connected with a first end thereof to a second end of the arm remote from the first end of the arm, and an engaging part, which is provided on a second end of the mast remote from the first end of the mast, said lifting device further comprising a lifting element comprising a base part and a lifting part, which base part is designed to be rigidly connected to the engaging part and which lifting part is connected to the base part, being designed to support an object to be lifted. Such a lifting device is known from JP 4 256 693 and JP 2005 067 751 .
US 5,813,697 discloses a known lifting device as described in the introduction, more specifically a telehandler. A telehandler is a mobile crane for lifting generally heavy objects, such as building materials. The known telehandler has a chassis-mounted base provided with a cabin, in which the operator of the telehandler can be seated. Mounting the base for rotation on the chassis is known, for that matter. The chassis is provided with wheels, so that the telehandler can be independently driven to the intended location, where it can be used for lifting objects. Connected to the base is a telescopic arm, which is pivotable relative to the base about a horizontal axis. At the end of the telescopic arm remote from the base, a mast connected to the telescopic arm is provided. The mast is provided with an engaging part, to which several tools can be connected. Think in this connection of a scoop, a tillage tool or a lifting element. The lifting element of the aforesaid known telehandler has a base part, which can be connected to the mast, and a lifting part, which is pivotally connected to the base part for movement about a vertical axis. A drawback of the above-described known telehandler provided with a lifting element is that manoeuvring the telehandler, more specifically the chassis with the telehandler base, for correctly picking up an object to be lifted is difficult and takes much time. This drawback plays a part particularly when the telehandler is used in an area where there is little room for manoeuvring, so that the telehandler must move forward and backward several times in order to take up a good position with respect to the object to be lifted. Accordingly it is an object of the present invention to provide a solution to the aforesaid drawback. This object is accomplished by the lifting device according to the present invention, which is characterised in that the third axis is located under the engaging part. By providing the third axis under the engaging part, space is created to enable the lifting part to make a complete rotation, or at least substantially a complete rotation, about the third axis, without said rotation being impeded by the engaging part or by the mast. An advantage of the lifting device according to the present invention is that because the lifting part is at least substantially fully rotatable with respect to the base part, it is no longer essential to position the base of the lifting device correctly relative to the object to be lifted. As a consequence, considerably less and, moreover, less precise manoeuvring is required, since the lifting part of the lifting element of the lifting device according to the present invention can be rotated in such a manner that the object can be easily lifted from several positions. Thus it is also possible when using such a lifting device to operate at a random angle (relative to the longitudinal direction of the base with the telescopic arm). With the aforesaid known telehandler, the rotation of the lifting part relative to the base part is limited on account of the presence of the engaging part in the path of movement of the lifting part.
A telehandler comparable to the known telehandler as described above is known from GB 1 455 952 . The mast of said known telehandler is pivotally connected to the telescopic arm for movement about a horizontal axis. The rotation of the lifting part relative to the base part of said known telehandler is limited on account of the presence of the telehandler mast in the path of a lifting part that is pivotable about a vertical axis.
The mast is preferably pivotally connected to the arm for movement about a horizontal second axis. As a result, the object can be held horizontally to a significant degree while it is being lifted.
In an advantageous preferred embodiment, said at least substantially vertical plane coincides with a vertical plane through, seen in horizontal direction, the centre of the arm and of the mast. Since the third axis is in this case in line with the centre of the mast and the arm, a greater ease of use of the lifting device is obtained.
The lifting element preferably comprises two mutually parallel elongate forks for forming a supporting surface for the object to be lifted. Furthermore preferably, the forks are provided on either side of the third axis, even more preferably spaced therefrom by at least substantially the same distance. If the third axis is in line with the centre of the mast and the arm, as described above, and preferably if the third axis is located under the engaging part, the bending moment exerted on the engaging part by the object will be minimal.
Controlling the rotation of the lifting part relative to the base part is significantly simplified if the supporting surface is oriented perpendicularly relative to the third axis.
The functionality of the lifting device is further enhanced if the engaging part is pivotally connected to the mast for movement about a horizontal fourth axis.
To minimise the aforesaid bending moment even further, it is advantageous if the third axis intersects the fourth axis or if the third axis crosses the fourth axis in direct vicinity.
An even higher degree of functionality of the lifting device is achieved if the arm is pivotally connected to the base for movement about a vertical fifth axis. Thus an action radius extending circularly around the base can be realised.
The operation of the lifting device is made easier if the horizontal first axis and the horizontal second axis extend parallel to each other. Thus the mast and the arm will remain in line upon pivoting about the first axis and the second axis, respectively.
The mobility of the lifting device is increased if the base is provided on a vehicle.
In an advantageous preferred embodiment, the base part of the lifting element comprises a plate, and the lifting part comprises a further plate which extends parallel to said plate, one of said plate and said further plate comprising a stub axle extending perpendicularly to said plate, the central axis of which stub axle coincides with the third axis, and the other one of said plate and said further plate comprising a recess, in which said stub axle is rotatably accommodated. In this way a simple yet robust construction is obtained for rotating the lifting part relative to the base part.
It is further advantageous in this regard if a number of rolling means are provided between said plate and said further plate for supporting said further plate on said plate. The rolling means are provided on one of said plate and said further plate, being designed to roll on the other one of said plate and said further plate during rotation of the lifting part. The bending moment acting on the stub axie by the object to be lifted by means of the lifting part is thus significantly reduced.
The rotation of the lifting part relative to the base part can be controlled in a simple manner if a gear wheel is provided on one of said plate and said further plate, said gear wheel being designed to mesh with a gear to be driven by a drive unit mounted on the other one of said plate and said further plate. Rotation of the lifting part is thus realised in a simple and accurate manner by suitable actuation of the drive unit. An advantage of mounting the drive unit on the base part, and thus of providing the gear wheel on the lifting part, is that no conduits to the lifting part for actuating the drive unit are needed, so that the lifting part can thus be rotated about the third axis at will and without limitations.
It is advantageous in that regard if the drive unit is hydraulically actuated. Since the above-described lifting devices generally already have a hydraulic driving system on board for controlling the arm and the mast, the drive unit for rotating the lifting part can thus simply be connected to the existing hydraulic driving system.
Preferably, the lifting part can be rotated through an angular range of at least 270 degrees about the third axis relative to the base part.
The present invention, according to a second aspect thereof, relates to a lifting element, in particular for use in a lifting device according to the first aspect of the invention, said lifting element comprising a base part and a lifting part, which base part is designed to be rigidly connected to an engaging part of the lifting device, and which lifting part is connected to the base part, being designed to support an object to be lifted, said lifting part being connected to the base part for rotation about a third axis lying in an at least substantially vertical plane, with the third axis being located under the engaging part, at least in the connected condition of the lifting element to the engaging part of the lifting device. The advantages of such a lifting element according to the present invention are analogous to the advantages of the lifting device according to the first aspect of the present invention as described above. It is conceivable within this framework to use the lifting element also in combination with lifting devices other than the one described in the foregoing, for example with a fork-lift truck or with a crane other than the mobile or stationary crane described in the foregoing.
The present invention will now be explained in more detail in the following description of a preferred embodiment of a lifting device according to the present invention, in which reference is made to the following figures:

Figure 1 is an isometric view of a preferred embodiment of a lifting device according to the present invention;
Figure 2 is an isometric view of the lifting device according to figure 1;
Figure 3 is a more detailed view of a part of the lifting device according to figure 1;
Figure 4 is a partially sectional side view of the part shown in figure 3.

In figures 1 and 2 there is shown a lifting device, more specifically a telehandler 1 according to the present invention. The telehandler 1 has a base 2 comprising an upper part 210, which can rotate relative to the lower part 220 via a slewing bearing 230. A cabin 240 is provided in the upper part 210, in which the operator of the telehandler 1 can be seated. Connected to the upper part 210 is a telescopic arm 3 which is pivotable about a horizontal axis relative to the upper part 210. The length as well as the angular position of the telescopic arm 3 can be changed hydraulically (not shown in more detail in the figures). A mast 4 is provided at the end of the telescopic arm 3 remote from the base 2. The mast 4 can pivot about a horizontal shaft 5 relative to the telescopic arm 3. The angular position of the mast 4 relative to the telescopic arm 3 can be set by actuating the piston-cylinder combination 301. An engaging part 6 is provided at the end of the mast 4 remote from the telescopic arm 3. The engaging part 6, which is shown clearly in particular in figure 3, is pivotally connected to the mast 4 for movement about a horizontal shaft 8 relative to the mast 4. The angular position of the engaging part 6 relative to the mast 4 can be set by means of the piston-cylinder combination 401.
As figure 3 shows, a lifting element 20 is connected to the engaging part 6. The lifting element 20 comprises a base part 21 and a lifting part 22. The lifting part 22 can rotate relative to the base part 21. The base part 21 has two vertical plates 202, which are mounted on a horizontal plate 25. Mounted between the plates 202 is a horizontally extending rod 201. The rod 201 is adapted to be received in recesses 61 provided in the engaging part 6 (see figure 4). The engaging part 6 furthermore has two horizontally translatable pins 62, which fall into corresponding holes in plates 202 of the base part 21 so as to fix the base part 21 relative to the engaging part 6 once the rod 201 is accommodated in the recesses 61. As a result of the rigid connection of the base part 21 to the engaging part 6, the base part 21, and with it the lifting element 20, can thus be pivoted about the horizontal shaft 8 relative to the mast 4.
The lifting part 22 of the lifting element 20 comprises a plate 28 and, connected thereto, a support 34 for forks 24a, 24b. The position of the forks 24a, 24b can be adjusted in horizontal direction. A stub axle 26 is fixed to the plate 25 of the base part 21, which stub axle extends perpendicularly in downward direction from the plate 25 in the direction of the plate 28. Seen in horizontal direction, transversely to the arm 3 and the mast 4, the stub axle 26 is located in the centre of the arm and the mast or, in other words, in line with the longitudinal direction of the arm and the mast. The central axis of the stub axle 23 also intersects the central axis of the horizontal pin 8. Furthermore, a number of runners 27 are provided on the underside of the plate 25. Mounted on the plate 28 of the lifting part 22, which is positioned parallel to the plate 25 of the base part 21, is a bush 29, in which the stub axle 26 can be received with a close fit. After the bush 29 has been moved over the stub axle 26, a locking ring 35 is fitted, which locking ring prevents the bush 29 from sliding downwards off the stub axle 26. The locking ring 35 is fitted in such a manner that the runners 27 roll on the plate 28 with a slight bias. The runners 27 are provided for the purpose of significantly reducing the bending moment exerted on the stub axle 26 by the object 7 to be lifted. Instead of using runners 27, it is also possible to provide a pivot bearing disposed between the plates 25 and 28, concentrically relative to the stub axle 23, which bearing has a diameter which is significantly larger than the diameter of the stub axle 23.
A gear wheel 30 is mounted on the plate 28 for controlling the rotation of the lifting part 22 relative to the base part 21. A hydraulic motor 22 is mounted on the plate 25, which motor comprises a shaft 37 extending downwards through the plate 25, on the end of which shaft a gear 31 is mounted. Thus the lifting part 22 can be rotated relative to the base part 21 by suitable actuation of the hydraulic motor 32. As figures 2 and 4 show, the location of the stub axle 23, or at least the central axis thereof, under the engaging part 6, and thus also directly under the end of the mast 4 at least remote from the telescopic arm 3, enables the lifting part to make a complete rotation in the horizontal plane. The hydraulic motor 32 can be connected to the hydraulic circuit that is already present on the telehandler 1.
The telehandler 1 has a significantly greater functionality and ease of operation, since it is also possible to lift objects disposed at positions beside the lifting element 20, i.e. objects not being in line with the telescopic arm 3 and the mast 4, by means of the telehandler 1. This means that, for example in the situation in which a pallet is to be lifted, the orientation of the pallet relative to the telehandler 1 per se is not relevant. In many cases, a pallet can only be accessed by the forks 24a, 24b of the lifting element from two of the four circumferential sides. With the telehandler 1 according to the present invention, the lifting part 22 of the lifting element 20 can first be rotated so that the forks 24a, 24b extend perpendicularly to the appropriate circumferential side of the pallet, after which the forks 24a, 24b are moved under the pallet. The base 2 of the telehandler can remain in its place, so that manoeuvring the base for picking up an object will not be necessary, or at least only to a minimal extent.

Claims

A lifting device (1) comprising a base (2), an elongate arm (3), which is pivotally connected to the base with a first end for movement about a horizontal first axis, an elongate mast (4), which is connected with a first end thereof to a second end of the arm remote from the first end of the arm, and an engaging part (6), which is provided on a second end of the mast remote from the first end of the mast, said lifting device (1) further comprising a lifting element (20) comprising a base part (21) and a lifting part (22), which base part is designed to be rigidly connected to the engaging part and which lifting part is connected to the base part, being designed to support an object (7) to be lifted, said lifting part (22) being connected to the base part (21) for rotation about a third axis (23) lying in an at least substantially vertical plane, characterised in that said third axis (23) is located under the engaging part (6).
A lifting device according to claim 1, characterised in that the mast (4) is pivotally connected to the arm (3) for movement about a horizontal second axis (5).
A lifting device according to claim 1 or 2, characterised in that said at least substantially vertical plane coincides with a vertical plane through, seen in horizontal direction, the centre of the arm (3) and of the mast (4).
A lifting device according to any one of the preceding claims, characterised in that the lifting element (20) comprises two mutually parallel elongate forks (24a, 24b) for forming a supporting surface for the object (7) to be lifted.
A lifting device according to claim 4, characterised in that the supporting surface is oriented perpendicularly relative to the third axis (23).
A lifting device according to any one of the preceding claims, characterised in that the engaging part (6) is pivotally connected to the mast (4) for movement about a horizontal fourth axis (8).
A lifting device according to any one of the preceding claims, characterised in that the arm (3) is pivotally connected to the base (2) for movement about a vertical fifth axis.
A lifting device according to any one of the preceding claims, characterised in that the horizontal first axis and the horizontal second axis (5) extend parallel to each other.
A lifting device according to any one of the preceding claims, characterised in that the base (2) is provided on a vehicle.
A lifting device according to any one of the preceding claims, characterised in that the base part (21) of the lifting element (20) comprises a plate (25), and the lifting part (22) comprises a further plate (28) which extends parallel to said plate (25), one of said plate (25) and said further plate (28) comprising a stub axle (26) extending perpendicularly to said plate (25), the central axis of which stub axle coincides with the third axis (23), and the other one of said plate (25) and said further plate (28) comprising a recess (29), in which said stub axle (26) is rotatably accommodated.
A lifting device according to claim 10, characterised in that a number of rolling means (27) are provided between said plate (25) and said further plate (28) for supporting said further plate (28) on said plate (25).
A lifting device according to claim 10 or 11, characterised in that a gear wheel (30) is provided on one of said plate (25) and said further plate (28), said gear wheel being designed to mesh with a gear (31) to be driven by a drive unit (32) mounted on the other one of said plate (25) and said further plate (28).
A lifting device according to claim 12, characterised in that the drive unit (32) is hydraulically actuated.
A lifting device according to any one of the preceding claims, characterised in that the lifting part (22) can be rotated through an angular range of at least 270 degrees about the third axis (23) relative to the base part (21).
A lifting element (20) in particular for use in a lifting device (1) according to any one of the preceding claims, said lifting element comprising a base part (21) and a lifting part (22), which base part is designed to be rigidly connected to an engaging part (6) of the lifting device (1), and which lifting part is connected to the base part, being designed to support an object (7) to be lifted, said lifting part (22) being connected to the base part (21) for rotation about a third axis (23) lying in an at least substantially vertical plane, characterised in that the third axis is located under the engaging part, at least in the connected condition of the lifting element to the engaging part of the lifting device.