WO1994007789A1

WO1994007789A1 - Lifting device with endless transporting means for loading and unloading

Info

Publication number: WO1994007789A1
Application number: PCT/SE1993/000742
Authority: WO
Inventors: Olle WAHLSTRÖM
Original assignee: Wahlstroem Olle
Priority date: 1992-09-28
Filing date: 1993-09-14
Publication date: 1994-04-14
Also published as: AU5121993A; SE9202796L; SE9202796D0

Abstract

Lifting equipment with a small vertical extension, which by a relative movement between the lifting equipment and a load unit (1, 2) to be lifted, from the side can be brought in under the load unit (1, 2), such as e.g. a fork (10), including at least one endless transporting means (18), extending along a main part of the length of the lifting equipment between a rear turning means (20) and a front turning means (19), at which a drive means, which at the same time can be constituted by a turning means (20), is arranged to drive the transporting means (18) in active working directions coinciding with the longitudinal direction of the lifting equipment, in that the transporting means (18) can feed in respectively feed out the load unit (1, 2) on/from the lifting equipment. The transporting means (18) shows a front portion (24) at the front turning means (19), intended to enter under the load unit (1, 2), extending in front of the fork (10) and the front turning means (19). The transporting means (18) is arranged to follow a track around the fork (10) and its return part runs in a space (15) on the lower side of the fork (10).

Description

Lifting device with endless transporting means for loading and unloading.

TECHNICAL FIELD

The invention concerns a lifting equipment with a small vertical extension and which by a relative move¬ ment between the lifting equipment and a load unit to be lifted can be brought in under the load unit from the side, such as e.g. a fork, lifting table or the corre¬ sponding for fork-lift trucks, lifting trolleys, piling trolleys, piling cranes and other load handling machines, which lifting equipment include at least one endless transporting means, extending along a main part of the length of the lifting equipment between a rear turning means and a front turning means. Drive means are arranged to drive the transporting means in active working direc¬ tions coinciding with the longitudinal direction of the the lifing equipment in that way that the transporting means can engage the underside of the load unit without sliding in order to make the transporting means to feed in respectively feed out the load unit on/from the lif¬ ting equipment. BACKGROUND TECHNICS

The up to now most used load carrier during the period after the World War II has been the traditional pallet made of wood. By an extensive international stan¬ dardisation of the design and format of the pallet com¬ plete transporting systems for its handling have been developed gradually. By that reason advanced truck equip¬ ment as well as simple, manual handling trolleys is pre- sent in most places for handling goods for loading and transporting of pallets.

Even if the pallet thus is extensively standar¬ dised and a load carrier is easy to handle, it shows cer¬ tain drawbacks such as e.g. a voluminous shape and a high weight. The cost for using pallets also during the time has become relatively high as a result of encreasing wood prices and a relatively short life of the pallet. The interest for pallet-free load handling and alternative, cheap load carriers by that has encreased during the last years.

By the new load carrier systems which have been brought during the last years different kind of load sheet systems using so called "slipsheets" or slippallets are the up to now best developed and most promising for the future. The slipsheet method means that a thin sheet of cardboard or paperboard is placed under the load and horisontally pulled on the truck forks by means of a special push/pull unit. When the load is to be unloaded the unit is used to push the goods placed on the load sheet from the truck forks. The known so called slippal- let differs from slipsheets mainly in that it is intended to be handled directly by a fork-lift truck without a push/pull unit, at which the forks of the truck are pushed under the sheet, the edge of which is bent up rounded, at the loading and can be made to slip from the forks by a tilting forward of the same at the unloading. A change-over to palletless load handling and new load carriers in the shape of slipsheets is expected increasingly. In USA, which is a pioneer country concer¬ ning slipsheet technics, a great part of the pallets have been replaced by slipsheets for every day commodities. Also in other branches handling unit loads load sheets are used encreasingly. A similar development as in USA can be expected also in other countries in which the pallet up to now has been the dominating load carrier. The most important obstacle to a more common introduction of palletless load handling and whith load sheets as load carriers is the lack of simple transpor¬ ting devices above all for manual loading, unloading and transporting of separate goods or goods loaded on load sheets. In order to handle slipsheets thus a truck pro- vided with a push/pull unit is required, for example ac¬ cording to the American patent publication US 2 818 189 at the sender as well as at the receiver of the goods. Even if more simple handoperated push/pull trucks has been brought it is to be taken in account that a trans¬ port device for push/pull handling of slipsheets is a considerable investment for small receivers of goods. Regarding the slippallet this can be handled without a push/pull unit but on the other hand a conventional motor-driven fork-lift truck with a tiltable fork-lift is required. Investment in such a truck many times is com¬ pletely unrealistic for most of the small receivers of goods, which at the most have the use of a manual pallet trolley with a hydraulic lifting unit for loading and unloading of common pallets. Many receivers of goods to day have no transporting means of their own but rely upon that loading and unloading will be made by the driver of the lorry by means of pallet handling devices brought with the lorry.

Also trucks with special motor-driven devices for direct loading and unloading of separate, nonpal- letized goods are previously known. As examples of loa- ding and unloading devices for fork-lift trucks can be mentioned reversibly driven transporting chains described in the Swedish patent publications SE-B--451 131 and SE-B-431 193.

A drawback with the special equipped trucks and other handling devices developed for the slipsheet tech¬ nics is that they are big, heavy and expensive. Another drawback, which is very important in this connection, is that they only can be used for palless handling based upon the slipsheet technics, which means that beside of these special devices also conventional fork-lift trucks, piling cranes e.t.c. must be used for handling of palle¬ tized goods. DESCRIPTION OF THE INVENTION

The purpose with the present invention is to bring about a lifting equipment with a small vertical extension and which by a relative movement between the lifting equipment and a load unit to be lifted, from the side can be brought under the load unit, such as e.g. a fork, lifting table or the corresponding for fork-lift trucks, lifting trolleys, piling trolleys, piling cranes and other load handling machines. The lifting equipment includes at least one endless transporting means, exten¬ ding along a main part of the length of the lifting equipment between a rear turning means and a front tur¬ ning means, at which a drive means, which on the same time can be constituted by a turning means, is arranged to drive the transporting means in active working direc¬ tions coinciding with the longitudinal direction of the lifting equipment, in that way that the transporting means without sliding can engage the underside of the load unit in order to make the transporting means to feed in respectively feed out the load unit on/from the lif¬ ting equipment. The lifting equipment according to the invention is characterized in that the transporting means or the corresponding device shows a front portion at the front turning means intended to establish a gap between the underside of a load unit and its carrier by penetra¬ ting under the load unit in that way that the transpor¬ ting means can be brought into an active engagement to the underside of the load unit at the front portion, that the transporting means extends with the front portion in front of the fork and the front turning means in a direc¬ tion to the load unit, and that the transporting means is arranged to follow a track around the fork or the corre¬ sponding, at which the return part of the transporting means is running in a space on the underside of the fork. Other details and features concerning the lif¬ ting equipment accordning to the invention will be clear from the description below and from the enclosed claims. DESCRIPTION TO DRAWINGS

The invention is described below as an embodi- ment in connection with the enclosed drawings.

Figure 1 shows two load units piled upon each other, which can be handled by means of the lifting equipment according to the invention.

Figure 2 shows a view of a lifting fork designed according to the invention.

Figure 3 shows the lifting fork according to figure 1 seen from the side.

Figure 4 shows a device in a bigger scale in a section along the line I-I in figure 3-

Figure 5 shows the device in the same scale as in figure 4 in a section along the line II-II in figure 3.

Figure 6 shows the device in a section along the line III-III in figure 3-

Figure 7 shows a first alternative embodiment of a lifting fork according to the invention seen from the side.

Figure 8 shows a lifting fork according to fi¬ gure 7 seen i view.

Figure 9 shows a part of the front portion of a lifting fork according to figure 7 and 8 in a section along the line IV-IV in figure 8.

Figure 10 shows an alternative embodiment of the lifting fork according to figure 9.

Figure 11 shows a part of the lifting fork ac¬ cording to figure 7 and 8 in a section along the line V-V in figure 8.

Figure 12 shows the use of the invention at a fork-lift trolley seen obliquely from behind.

Figure 13 shows the fork-lift trolley according to figure 12 in a loading or unloading position. Figure 14 shows the fork-lift trolley according to figure 12 and 13 in a transporting position.

Figure 1 shows two load units 1 and 2. The lower load unit 1 includes a lower load sheet 3, so called slipsheet, and an upper load sheet 4. The upper load unit 2 includes a corresponding lower load sheet 5. The load sheets 3_> 4, 5 can be constituted by papercardboard, plastic or the similar. Preferably however they are constituted by fibre board and provided with bent tounges or brims 6 outside the load surface. The brims 6 on the lower load sheets 3 and 5 are bent upwards, as the brim 6 of the load sheet 4 constituting an upper cover of the load unit 1 is bent downwards as shown in figure 1. The lower load unit 3 is resting directly on a floor or an another pad. The purpose of the invention is to offer a lifting equipment which can be applied below the lower load carrier 3 respectively below the load carrier 5, e.g. in the latter case between the two load carriers 4 and 5.

The lifting equipment shown in figure 2-6 inclu¬ des a fork 10. This is constituted by a carrying plane 11 extending horisontally from a a bracket 12. The carrying plane 11 is constituted by a carrying plate 13 and, at the sides of this plate, by a couple of stiffening side plates 14. These are tapering from the brackets 12 to the front end of the carrying plane 11. At the upper side the side plates 14 extend to a lower level than the underside of the carrying plate 13_> figure 4, 5 and 6. In that way a free space 15 is constituted and limited by the under¬ side of the carrying plate 13, the inner sides of the side plates 14 and a pad, to which the side plates 14 are resting, e.g. the upper side of a load sheet 4. The bracket 12 is constituted by a couple of side plates 16, which are welded to the side plates 14 of the carrying plate 13. A couple of hooks 17 are screwed between the side plates 16. By means of the hooks 17 two forks 10 can be mounted upon a fork-lift truck. A conveyor belt has the reference number 18.

This is constituted by a material with a high tensile strength, a very heigh friction coefficient to the load sheet 3, 5 and a very small friction coefficient on the side which is facing the carrying plate 13. A suitable material is a material which is manufactured by the Swiss company Habasit AG and which is traded under the trade¬ mark Habasit FAB-5E. The conveyor belt 18 extends in a track following the upper side of the carrying plate 13, turns around a front fix bar 19 of stainless steel, fol¬ lows the underside of the carrying plate 13 in the free space 15 between the side plates 14, turns around a dri- ving roll 20 between the side plates 16 of the bracket 12 and is after that bent down under a stretch roll 21, which also is arranged in the space on the bracket 12. The driving roll 20 is powered by a hydraulic motor with a hydraulic pressure from the hydraulic system of the fork-lift truck. The two forks 10 arranged on a fork-lift truck are separately driven. In figure 4 the bearing of the driving roll 20 is given the reference number 22, and in figure 5 the bearing of the stretch roll 21 is given the reference number 23. At the front part of the carrying plane 11 the conveyor belt 18 shows a front portion 24, as shown in figure 3, at which the bar 19 is screwed to the front part of the side plates 14 by two side shanks 25. The shape of the shanks 25 corresponds to the shape of the side plates 14 when mounted. The front portion 24 of the conveyor belt 18 projects to the load sheet 3, 5.

A truck provided with two forks 10 of the kind described is used in the following way. At loading of a load unit, as e.g. the upper load unit 2 in figure 1, the truck is brought forward in the same way as at normal handling of pallets. The forks 10 are brought into the gap between the load sheets 4 and 5 starting between the bent side edges 6. At the same time as the driver broughts the truck in a direction to the load unit the conveyor belt 18 is driven by means of the hydraulic mo¬ tors 20 backwards on the carrying plates 13. As the forks 10 in that way are brought a bit under the load unit 2, the driver can stop the truck but continue the driving of the conveyor belts 18. Because of the big friction/ adhesion between the upper side of the conveyor belt 18 and the under side of the load sheet 5 the two conveyor belts 18 further will pull the load unit 2 on to the two forks 10 during a slipping between the two load sheets 4 and 5. If a slipping should occur between one fork 10 and the conveyor belt 18 and the load sheet 5 causing an in¬ clination this can be met by the separate driving of the two hydraulic motors 20. When a load unit is to be unloa¬ ded this will be made in an analogous but opposite way. The lifting equipment shown in figure 7-8 in¬ cludes a fork 30 showing a carrying plane 31, extending horisontally from a bracket 32. The fork 30 carries two first roller chains 33 running along the carrying plane 31 and projecting from the same at the upper side of the fork 30 to a front turning means 34 at the tip of the fork 3. The first roller chains 33 after that run back on the under side of the fork 30 in a groove 35 to a roller chain sprocket 36 driven by a hydraulic motor 37. The first roller chains 33 are of so called triplex type, i.e. including three rows of rolls arranged to roll on tracks 39 in the bottom of the grooves 35. The first rol¬ ler chains 33 are tightened by means of a tightener roll 38. A second roller chain 40 is placed between the two first roller chains 33 and running to the front end of the fork 30 projecting down from the fork 30 on its un¬ derside. The second roller chain 40 after that runs back in a groove in the fork 30 in a distance below the upper parts of the first roller chains 33 and preferably com¬ pletely enclosed in a groove 41 in the fork 30.

At loading of a load unit, such as the upper load unit 2 in figure 1 , a truck is brought forwards as at normal handling of pallets. The forks 30 are entered into the gap between the load sheets 4, 5 starting bet¬ ween the bended side edges 6. At the same time as the driver brings the truck to the load unit 2 the two first roller chains 33 are powered in that way that their parts on the carrying plane 31 move to the rear end of the fork 30 at the bracket 32. Thereby the first roller chains 33 tend by their front parts 42 to lift the load unit 2 when moving upwards at the front edge 34 on each fork 30, which facilitates the moving in under the upper load sheet 5. After that the first roller chains 33 tend to pull the load unit 2 to the bracket 32. During the entry of the forks 30 between the load sheets 4, 5 each fork 30 rests with the second roller chain 40 to the lower load sheet 4 thus lowering the resistance at the entry of the forks 30.

The first roller chains 33 as well as the second roller chain 40 in each fork 30 include links 43, showing rounded ends facing each other which connects the rollers 44 in the chains. In the alternative embodiment of the first roller chains 33, shown in figure 10, the links 43 show sharp edges 45, which encrease the engagement to the upper load sheet 5 as the forks 30 are brought to the load unit 2, improving the ability of the first roller chains 33 to engage the load unit 2.

In figure 12-14 a trolley according to the in¬ vention is shown where the friction-lowering means of the load deck is constituted by two endless conveyor belts 50. The embodiment of the trolley shown is to prefer to be able to handle goods loaded on load sheets as well as on pallets. This will be possible in that the trolley is designed as a traditional pallet lifting trolley with two forks, upon which the two endless conveyor belts 50 are arranged to run around a driving roller 62. These rollers are rotatable mounted at the front respectively rear ends of two deck arms 58, which are tiltable mounted on a shaft 60 on each fork. As the trolley shown in figure 4 is situated in its lower loading or unloading position the front ends 55 of the deck arms will slope to the ground plane 57 because of the placing of the weight in relation to the tilting axis, making the wedge-shaped front ends to be entered respectively pulled out from the space between the ground plane and the load sheet 51 with its goods 52. As the trolley is pushed in under the load sheet the upper part of the belt, on which the load sheet is resting, by means of the driving roller 62 is moved to the left in figure 13, at which the trolley can be pushed in under the load without effecting its relative position to the ground plane. In order to lower the friction for¬ ces between the conveyor belts and the upper sides of the deck arms the sliding surfaces can be treated with a friction-lowering agent. Alternatively supporting rollers can be arranged on the upper sides of the deck arms. In an alternative embodiment of the trolley the conveyor belts 50 can be replaced by roller chains of the kind which is described above to figure 7-11.

As the load is in a transporting position on the load deck this is raised to a position shown in figure 14. This raising is made by means of conventional, manu¬ ally operated lifting means 53, 54 at which the deck arms 58 are lifted into a horisontal position by raising of the arms.

The above described variant of the lifting trol¬ ley according to the invention only constitutes one exam¬ ple of a suitable embodiment which also can be used for transport of conventional pallets. Such a combinated trolley is to prefer by commersial as well as handling aspects.

Claims

1. Lifting equipment with a small vertical extension and which, by a relative movement between the lifting equipment and a load unit (1, 2) to be lifted, from the side can be brought in under the load unit (1, 2), such as e.g. a fork (10), lifting table or the cor¬ responding for fork-lift trucks, lifting trolleys, piling trolleys, piling cranes and other load handling machines, which lifting equipment includes at least one endless transporting means (18), extending along a main part of the length of the lifting equipment between a rear tur¬ ning means (20) and a front turning means (19), at which the transporting means (18) is arranged to follow a track around the fork (10) or the corresponding lifting means, at which its return part runs in a space (15) on the under side of the fork (10), and at which a drive means, which on the same time can be constituted by a turning means (20), is arranged to drive the transporting means (18) in active working directions coinciding with the longitudinal direction of the lifting equipment, in that way that the transporting means (18) without sliding can engage the underside of the load unit (1, 2), in order to make the transporting means (18) to feed in respectively feed out the load unit (1, 2) on/from the lifting equip- ment , c h a r a c t e r i z e d in that the endless transporting means (18) shows a front portion (24) exten¬ ding freely in front of the fork (10) or the correspon¬ ding lifting means at the front turning means (19) in a direction to the load unit (1, 2), and which is intended by entry under the load unit (1, 2) to establish a gap between the under side of the load unit and each pad in that way that the transporting means (18) can be brought into an active engagement with the underside of the load unit (1, 2) at the front portion (24).

2. Lifting equipment according to claim 1, c h a r a c t e r i z e d in that the transporting means is constituted by at least one endless conveyor belt (18) resting on a carrying plane (31) on the upper side of the fork (10).

3. Lifting equipment according to claim 1, c h a r a c t e r i z e d in that the transporting means is constituted by at least one first roller chain (33), which is rolling by rolls (44) in this chain (33) along a corresponding roller track (39) on the upper side of the fork (30).

4. Lifting equipment according to claim 3, c h a r a c t e r i z e d in that the first roller chain (33) includes links (43) showing driving dogs (45) inten¬ ded to make an encreased engagement to the load unit (1, 2).

5. Lifting equipment according to claim 3 or 4, c h a r a c t e r i z e d in that at least one roller means (40) is arranged on the lower side of the fork (30) intended to rest to a pad or a floor or another load unit (1).

6. Lifting equipment according to claim 5, c h a r a c t e r i z e d in that the roller means is constituted by at least a second roller chain (40) exten¬ ding from the lower side of the fork (30) and rolling by rolls in this chain (40) on a corresponding roller track (39).

7. Lifting equipment according to any of the claims 1-6, c h a r a c t e r i z e d in that transpor¬ ting means (50) are arranged on a deck plane (58) e.g. on a lift fork on a trolley, which is tiltable between a loading/unloading position, in which the deck plane (58) is sloping to the pad, and a transporting position, in which the deck plane (58) is mainly horisontally.