WO2006078156A1

WO2006078156A1 - Transporting device with lifting platform with integrated conveyor

Info

Publication number: WO2006078156A1
Application number: PCT/NL2006/000026
Authority: WO
Inventors: Sjoerd Meijer; Hendrik Meijer
Original assignee: Gebr. Meijer St. Jabik B.V.
Priority date: 2005-01-20
Filing date: 2006-01-18
Publication date: 2006-07-27
Also published as: NL1028078C2

Abstract

The invention relates to a transporting device (1) such as a fork-lift truck, comprising a frame (9) , a lifting platform(3) such as a fork, which is arranged on the frame for movement in the height and which defines a carrying surface, with a conveyor (8) integrated into the carrying surface, wherein the conveyor can be incorporated in the carrying surface such that it can engage on the underside a load resting thereon.

Description

TRANSPORTING DEVICE WITH LIFTING PLATFORM WITH INTEGRATED CONVEYOR

The invention relates to a transporting device such as a fork-lift truck, comprising a frame, a lifting platform, such as a fork, arranged on the frame for movement in the height, wherein this lifting platform defines a carrying surface . Such transporting devices in the form of fork-lift trucks are generally known. A load received on the lifting platform can be displaced and set down at a random location in simple and skilful manner .

To enable proper engagement of the load, it is usually placed on for instance a pallet which is provided with recesses for the lifting platform. It is however also the case that a load lies directly on the ground or on another load, without space being provided for insertion of the lifting platform. This occurs for instance when use is made of so-called slip mats . These are thin, flexible plastic plates on which the load is arranged.

In such a case it is difficult to move the load, optionally together with the slip mat, onto the lifting platform. The transporting device as characterized in claim 1 does however make this possible in simple manner . The conveyor integrated into the carrying surface of the lifting platform can move the load on and off the lifting platform.

In a favourable embodiment the conveyor is incorporated in the carrying surface such that it can engage on the underside a load resting thereon . As soon as the underside of the load comes into contact with the conveyor, the load can thus be moved on and off the lifting platform. It is thus not necessary for this purpose for the lifting platform to be first manoeuvred wholly beneath the load.

In another suitable embodiment of the transporting device according to the invention the conveyor is connected to an engaging device for a slip mat . The transporting device can be positioned with the lifting platform adj acently of the load placed on a slip mat, whereafter the load can be pulled onto the lifting platform by placing the engaging device into engagement with the slip mat . The conveyor can then pull the slip mat with the load thereon onto the lifting platform.

A suitable embodiment is characterized here in claim 4. A further favourable development of the transporting device, and in particular the engaging device thereof, is characterized in claim 5. When the conveyor moves the engaging device in the one direction a slip mat can slide easily under the tilt lever. When the conveyor is driven in an opposite direction, the tilt lever will press the slip mat against the clamping surface, and thus engage the mat . The operative of the transporting device does not therefore have to perform any separate operations to place the engaging device in engagement, other than reciprocally moving in suitable manner the conveyor integrated into the carrying surface of the lifting platform. A suitable embodiment of the transporting device according to the invention is characterized in claim 6. The endless element can move round, wherein the part of the endless element received in the carrying surface can be driven in the appropriate direction . The endless element is preferably a roller chain . A roller chain is a standard structural element which is available with great precision and quality at relatively low cost . Also because the roller chains are manufactured from high-quality material, the use thereof can result in a long lifespan of the conveyor .

The measure of claim 8 is applied in suitable manner . The roller chain is accommodated in the lifting platform with lateral protection and, depending on the embodiment, can protrude above the lifting platform with a small part of its upper surface for the purpose of directly engaging the load. In an application in which the conveyor is intended only for driving an engaging device, the roller chain can lie fully recessed into the lifting platform.

The measure of claim 9 is preferably applied, particularly in the application where the conveyor can engage a load directly on its underside . The number of mutually adj acent roller chains forms the same number of mutually adjacent engaging surfaces . A considerable engaging surface area can hereby be achieved so that the load to be picked up is properly carried along by the roller chain with certainty.

The measure of claim 10 is preferably applied in order to enable the most slender possible embodiment of the lifting platform at its free end. The drive device does not then impede when the lifting platform is placed under a load.

According to a further embodiment, the measure of claim 11 is applied. The load does not then have to slide over the lifting platform, but rolls over the lifting platform in practically frictionless manner.

The measure of claim 12 is preferably further applied. The pointed end of the lifting platform can be easily placed under a load, or in particular a slip mat on which the load rests, even when there is no free space of any consequence under the load or the slip mat .

In order to enable smooth movement of the pointed end of the lifting platform under the load after initial insertion thereof, the measure of claim 13 is preferably applied. According to a favourable further development, the guide rollers are here arranged in per se known manner in two rows lying one above the other and in mutual contact, these rows protruding on the top and bottom side of the pointed end. The part of the load in contact with the end provided with the guide rollers will remain immobile relative to the surroundings when the bottom rollers roll over the underlying surface, while the point of the lifting platform still moves smoothly under the load. The transporting device according to the invention is preferably embodied as a fork-lift truck, wherein the lifting platform comprises a number of fork elements and the transporting device has a direction of movement which lies in the longitudinal direction thereof . The invention will be further elucidated in the following description of a preferred exemplary embodiment with reference to the accompanying figures .

Figure 1 shows a perspective view of the transporting device according to the invention in the form of a fork- lift truck with a lifting platform formed by two fork parts .

Figure 2a shows a perspective view on larger scale of one of the fork parts of the fork-lift truck of figure 1. Figure 2b shows another embodiment of the fork part of figure 2a .

Figure 3 shows a broken-away perspective view according to arrow III of a part of the conveyor . Figure 4 shows a longitudinal section of the fork part according to figure 2a . Figure 5 shows a perspective view of the transporting device according to the invention in the form of a fork- lift truck, wherein the conveyor carries an engaging device for slip mats . Figure 6 shows a partly perspective view of the fork part of the device of figure 5, with the engaging device for a slip mat .

Figure 7 shows a partly broken-away side view of the device according to figure 6, as seen in the direction of arrow VII . Figure 8 shows a partial section of the fork part of figure

2a along line VIII-VIII .

The transporting device according to the invention embodied as fork-lift truck 1 comprises a frame 9 with a mast 2. A lifting platform 3 movable in the height is arranged on mast 2 in per se known manner. Lifting platform 3 is formed more particularly by two fork parts 4 of a lift fork. The upper surface of the two fork parts 4 defines a carrying surface for a load 5.

It is usual to dispose a load 5 on a pallet 6, into which a space is recessed for inserting fork parts 4.

With fork-lift truck 1 it is however also readily possible to take up loads 5 which are not disposed on a pallet 6, but for instance on a slip mat 7.

In order to pick up for instance the upper load 5 of the stack consisting of three loads 5 with intermediate slip mats 7 , fork-lift truck 1 is for instance placed with fork parts 4 almost against the uppermost but one load 5, just below the slip mat 7 situated above this load. By then moving the fork slightly upward the edge of slip mat 7 is engaged and the fork can slide beneath slip mat 7 and over the load 5 lying thereunder .

As shown in figure 2a, in the preferred embodiment shown here of fork-lift truck 1 the foremost part of fork part 4 has a form which tapers to a point at the free end. Fork part 4 can hereby slide easily beneath a load 5.

In the embodiment shown in figure 2a the end part 25 is provided with rollers 26. Rollers 26 are arranged in per se known manner in two rows lying one above the other and in mutual contact, these rows protruding slightly on the top and bottom side of fork part 4. See also figure 4. When the lower rollers move over a surface, the upper rollers will be driven by the lower rollers such that as a result the upper surface of the upper rollers will have a speed of zero relative to the lower surface . This facilitates the sliding under of fork part 4. As figure 2b shows however, it is also possible to embody end part 25 with a sliding surface 27. This sliding surface 27 can for instance be provided with a material with a low coefficient of friction, such as PTFE .

According to the invention the fork part 4 is provided with a conveyor 8 integrated into the carrying surface . In the embodiment shown here this conveyor is formed by three endless elements in the form of double roller chains . These roller chains 12 are mounted in guide tracks 11 recessed, for instance milled, in the horizontal part 10 of fork part 4. At the end of horizontal fork part 10 situated close to mast 2 , the three roller chains are trained around toothed wheels 20 arranged on a shaft 19. Shaft 19 is bearing-mounted using bearing blocks 17.

The upper parts of the three roller chains are arranged such that they protrude just above the carrying surface, whereby the top side of the roller chains can engage on the underside of a load 5.

The middle chain of the three roller chains 12 is guided round a guide piece 18 mounted above shaft 19, so that a part of the relevant roller chain 12 extends upward along the vertical part 15 of fork part 4. As show in figure 1 , this upward guided part of roller chain 12 is trained round a drive gear of a drive motor 22. By switching on said drive motor 22 in suitable manner, the chain 12 trained therearound is thus driven in one direction . Because said chain is in engagement with a toothed wheel arranged on shaft 19 and the two remaining chains also engage on chain wheels 20 arranged on this shaft 19, all three chains are driven in equal measure . Depending on the direction of rotation of drive motor 22 , the upper part of roller chain 12 moves toward or away from end part 25.

The horizontal part 10 of fork part 4 is connected to vertical part 15 by connecting pieces 16 such that a strong fork construction is obtained.

Figure 4 more particularly shows the manner in which roller chains 12 can be tensioned. Tensioning device 30 comprises on each bearing block 17 a protruding threaded end 31 which is received in a bore in the horizontal part 10 of fork part 4. Two nuts 32 , 33 are arranged on this threaded end 31 between horizontal part 10 and bearing block 17. By- turning the nut 32 on threaded end 31 the position of bearing block 17 can be adjusted relative to the horizontal part 10 of fork part 4. The chosen position at which roller chain 12 is sufficiently tensioned can be secured by tightening the nut 33.

Fork-lift truck 35 according to the invention shown in figure 5 is provided with fork parts 36 which are provided with a conveyor, which is connected to an engaging device 37 for a slip mat . A roller chain 38 is mounted in each fork part 36, substantially in the manner described above with reference to the foregoing figures, wherein the upper surface of chain 38 can however lie at a lower level than the carrying surface of the forks . This is shown in more detail in figure 7.

In addition to a conveyor, fork part 36 also comprises a roller track 39 on either side of the roller chain . As is shown in more detail in figure 6, engaging device 37 comprises a slide 40 which can be displaced over the carrying surface of fork part 36. A tilt lever 42 drawn in cross-section in figure 7 is connected rotatably to this slide 40 by means of a pivot shaft 43. An arm 44 of tilt lever 42 protruding downward from pivot shaft 43 is connected to roller chain 38 by means of a hinge pin 45. Another arm 46 of tilt lever 42 carries on its underside a clamping surface 47 which co-acts with upper surface 48 of slide 40. A slip mat 7 can be clamped between this clamping surface 47 and upper surface 48. It will be readily appreciated that, if the upper part of roller chain 38 is driven in the direction of arrow 49 , a moment is exerted on tilt lever 42 in the direction of arrow 55 round pivot shaft 43. Clamping surface 47 is hereby pressed firmly against upper surface 48 of slide 40 and a slip mat 7 received therebetween is firmly clamped.

When the conveyor is driven in the opposite direction, tilt lever 42 will tilt in precisely the opposite direction, whereby a fixedly clamped slip mat 7 is released. During operation the fork therefore simply has to be positioned in the above described manner with the ends directly below the protruding part of the slip mat, whereafter engaging device 37 is moved forward using the conveyor until arm 46, and in particular clamping surface 47 thereof, is situated above the edge of slip mat 7 and the upper surface 48 of slide 40 under the edge . When roller chain 38 is now driven again in the direction of arrow 44 , i . e . in the direction toward the mast of the fork-lift truck, slip mat 7 is automatically clamped and slip mat 7 with the load 5 situated thereon is pulled onto the fork. The slip mat herein rolls over roller tracks 39 in the fork parts .

When the load must be set down, the conveyor is once again driven in opposite direction, wherein connecting beam 56 of the engaging device, which mutually connects the tilt levers 42 on either side, pushes load 5 off the fork. As soon as the load is in place, the fork-lift truck can retract the fork since the engaging device releases automatically in the above described manner .

Figure 8 shows a preferred embodiment of guide track 11 of the fork part shown in figure 2. Guide track 41 of figure 7 can also be embodied in corresponding manner .

As shown in the cross-section, guide track 11 is embodied with three grooves 54 and two ridges 53 lying therebetween . The level of ridges 53 is so much higher than that of grooves 54 that rollers 52 of roller chain 12 can roll thereover without the plates 51 of the chain coming into contact with the bottom of grooves 54. As known, a duplex roller chain shown in the figures is constructed from links , consisting of plates 51 , which are mutually connected with a pin 50 on which rollers 52 are bearing-mounted. The upper side of plates 51 is situated slightly above the upper surface of the horizontal part of fork-lift part 4 so that the load or slip mat for transporting can rest thereon . During operation of the conveyor the rollers 52 will thus roll over ridges 53 so that a low-friction transport movement is realized.

It is noted that in the embodiment wherein the conveyor drives an engaging device, as shown in figures 6 and 7 , the roller chain can lie at a lower level . The upper edge of plates 51 does not bear the load here . This is engaged and driven by the engaging device .

Claims

1. Transporting device such as a fork-lift truck, comprising a frame, a lifting platform, such as a fork, which is arranged on the frame for movement in the height and which defines a carrying surface, characterized by a conveyor integrated into the carrying surface .

2. Transporting device as claimed in claim 1 , wherein the conveyor is incorporated in the carrying surface such that it can engage on the underside a load resting thereon .

3. Transporting device as claimed in claim 1 or 2, wherein the conveyor is connected to an engaging device for a slip mat .

4. Transporting device as claimed in claim 3, wherein the engaging device comprises a slide displaceable over the carrying surface.

5. Transporting device as claimed in claim 3 or 4 , wherein the engaging device comprises a tilt lever which is connected pivotally to the slide and of which one arm is connected to the conveyor and another arm bears a clamping surface for a slip mat lying opposite an upper surface of the slide .

6. Transporting device as claimed in claim 2 , wherein the conveyor comprises at least one endless element, one part of which is received in the carrying surface such that said part can directly or indirectly engage on the underside a load resting thereon.

7. Transporting device as claimed in claim 6, wherein the endless element is a roller chain .

8. Transporting device as claimed in claim 7 , wherein the lifting platform comprises a recessed guide track for the roller chain.

9. Transporting device as claimed in either of the claims 7-8 , comprising a number of roller chains which are arranged parallel to and adj acent of each other and which are each guided round shafts placed at a mutual distance and provided with chain wheels .

10. Transporting device as claimed in any of the foregoing claims , wherein a drive device for the conveyor is arranged close to the end of the lifting platform connected to the frame .

11. Transporting device as claimed in any of the foregoing claims , wherein the lifting platform comprises a number of guide rollers with a rotation axis perpendicularly of the direction of movement of the conveyor .

12. Transporting device as claimed in claim 11, wherein the lifting platform has a pointed end opposite the end close to the frame .

13. Transporting device as claimed in claim 12, wherein the part tapering to a point is provided with guide rollers .

14. Transporting device as claimed in claim 13 , wherein the guide rollers are arranged in two rows lying one above the other and in mutual contact, these rows protruding on the top and bottom side from said part .

15. Transporting device as claimed in any of the foregoing claims, being a fork-lift truck, wherein the lifting platform comprises a number of fork elements and the transporting device has a direction of movement which lies in the longitudinal direction thereof .