The invention relates to a method for providing the lifting effect of a lifting transport trailer, wherein the main parts of the trailer comprise a ^■ frame with an essentially horizontal carrying plane or the like, and a lever mechanism comprising:

- a first lever frame which is articulated to the frame to rotate substantially in a vertical plane with respect to the frame and which is connectable to an apparatus or the like provided with means for vertical motions,

a second lever frame which is articulated to the frame to rotate substantially in a vertical plane with respect to the frame and which is equipped with at least one rotating organ such as a bearing wheel, and

at least one power transmission organ functioning between the first and the second lever frame for transmission of the vertical rotational motion of the first lever frame with respect to the frame of the said lifting transport trailer into the rota¬ tional motion of the second lever frame and thus for the change, limited by limiter means or the like, of the vertical distance between the carrying plane of the frame and said at least one rotating organ, particularly in connection with operations related to the loading of the lifting transport trailer.

As indicated above, the lifting transport trailer according to the invention is intended particularly for handling of goods, whereby the method according to the invention and the lifting transport trailer used

in it are particularly advantageously embodied in the principle of self-loading and self-unloading, used for transportation of loads on pallets. However, the invention is not limited to uses of this kind only, but naturally also other embodiments suitable for use in the handling of goods are possible.-

As to the principle of self-loading and self-unloading presented above, the prior art in this field can be illustrated by reference to the patent FI-79061. From this publication, a combination of a lifting transport trailer and a drawgear is known, which is used in combination with a drawing vehicle. In the embodiment according to the said patent, the motion of the frame lifting and lowering the load placed on a bottom is hydraulically operated. A lifting transport trailer made according to this principle is functional; however, it has the disadvantage of structural com¬ plexity, which increases the expenses on service, repair and manufacture. An apparatus of relatively complex technology, it is also subject to faults, which increases the risk of damage and thus of stand¬ stills e.g. related to loading and unloading of ships at harbour terminals. For reasons of efficient use of tied-up capital, it is particularly at sites of this kind that reliable lifting transport trailers are required. In use, the lifting transport trailer according to the patent has the disadvantage that the keyboard for controlling the operations of the lifting transport trailer is, in principle, placed loose within the cab of the drawing vehicle, so that in certain situations in practice, the keyboard may be difficult to control by the driver of the drawing vehicle.

Further, the publications CH-52,709 and GB-1,500,502 can be introduced as prior art to the invention. From these publications, mechanical solutions are known,

in which a carrying plane driven by a drawing vehicle, running on wheels and supporting the load is movable in the vertical plane with respect to the wheels. A disadvantage to the embodiments according to the said publications is that they cannot be moved away from below or below the load, and they are thus not suitable for embodiments with the particular principle of self-loading and self-unloading. Moreover, it must be stated particularly of the solution according to GB-1,500,502 that the vertical force e.g. on its first lever arm which is used to move the lever arm, or the removal of the force, always induces a change in the vertical distance between the frame (i.e. the carrying plane) and the wheels, irrespective of whether there is a load on the carrying plane or not. In other words, irrespective of the load, the movement of the first lever arm in the vertical direction always, within the limits by the limiter means in the apparatus, induces a change in the distance between the frame and the wheels, so that e.g. in the lower position, the frame rests on the ground or on a corresponding horizontal bottom. Because of this feature, the solution according to the said patent is unsuitable also for many other uses.

It is an aim of the present invention to eliminate substantially the drawbacks of prior art presented above and to achieve a reliable method with various uses for providing the lifting effect of a lifting transport trailer. Thus, the method according to the invention is particularly intended to improve the level of prior art in the field. For achieving these purposes, the method according to the invention is mainly characterized by the following phases:

electing the factors effective on the quantity of the moments at the point of articulation between the second lever frame and the frame in a manner

that the lifting transport trailer functions during shifting of the lifting transportation trailer as a stiff body at least in two positions, wherein, in the first position, the sum of the moments at the point of articulation effects in the first direction so that the lever mechanism comprising the lever frames and at least one power transmission organ is supported against the first limiter means or the like in the frame, the carrying plane being in the lower position, and

- changing at least one factor effective on the quantity of the moments at the point of articula¬ tion between the second lever frame and the frame in a manner that the sum of moments at the point of articulation of the second lever frame is turned in the second direction which is opposite to the first direction, wherein the lifting transport trailer functions during shifting of the lifting transportation trailer as a stiff body in the second position so that the lever mechanism com¬ prising the lever frames and at least one power transmission organ is supported against the second limiter means or the like in the frame, the carrying plane being in the upper position.

Consequently, this solution has the advantage that the lifting transport trailer can be shifted as a stiff piece, the carrying plane being in the lower position, so that the height position of the first lever frame is freely adjustable according to the respective shifting situation. Particularly in a situation of load shifting, as the carrying plane of the lifting transport trailer is to be lifted in the upper position, this can be performed by simple operations which will be described in more detail further on, and/or in connection with the loading stage, which is advantageous particularly when the

lifting transport trailer is used according to the principle of self-loading and self-unloading. Thus, it must further be noted that the lifting transport trailer functions as a stiff body also in the upper position, wherein the height position of the second lever frame is freely adjustable within ^• functional limits to suit each shifting situation. A particular advantage is gained by the fact that, in certain embodiments of the invention, the height position of the carrying plane is freely adjustable between the upper and lower positions, irrespective of the load on the carrying plane; namely, the lifting transport trailer can be used also in other methods of handling goods, in addition to the principle of self-loading and self-unloading.

In applying of the principle of self-loading and self-unloading, one embodiment of the method according to the invention, in which the lifting transport trailer is placed below the load lifted by a support device from the horizontal level for the purpose of shifting the load, the carrying plane being in the lower position, and the carrying plane is lifted to bring the load to the support of the carrying plane, particularly for purposes of shifting the load, is characterized by the following phases:

lifting in the first phase for bringing the load to the support of the carrying plane, the first lever frame upwards, wherein the lifting transport trailer is rotated as a stiff body in the first position so that the carrying plane meets the load and/or the support device connected to the load, with which the load is supported in the lifted position, and the frame is subjected to a force directed by the said load and/or the support device changing the direction of the moments effective at the point of articulation of the

second lever frame to the opposite and thus bringing the lifting transport trailer to a second position, and

- placing the said load in relation to the carrying plane in a manner that the position of the joint centre of gravity of the frame and the load in relation to the position of the centre of gravity of the frame is changed for arresting the lifting transport trailer in a second position.

Consequently, the solution presented above provides an automatic function during loading and naturally during unloading, which is based on a mechanic prin- ciple and triggered by the meeting of the load and the carrying plane during rotation of the lifting transport trailer as a stiff body upwards in the first position and, in an unloading situation, by the meeting of the support device of the load and the bottom during rotation of the lifting transport trailer as a stiff body downwards in the second position.

Advantageously, according to an alternative embodiment of the invention, the lever relations of the first and/or the second lever frame and/or the position of the centre of gravity of the frame are changed for achieving the first or the second position. As already mentioned, these solutions can be used separately and/or in combination with the principle of self- loading and self-unloading mentioned above.

Furthermore, the invention relates to a lifting transport trailer, which is mainly characterized by the features disclosed in the characterizing part of the attached independent claim related to the lifting transport trailer. The attached dependent claims related to the lifting transport trailer disclose some advantageous embodiments thereof.

One advantageous embodiment of the invention is illustrated in more detail in the following descrip¬ tion with reference to the attached drawings. In the drawings,

Figure 1 shows a fractional view of one lever mechanism of the lifting transport trailer used in the method according to the invention,

Figs. 2a,2b show side views of the lifting transport trailer with lever mechanism according to

Fig. 1 when unloaded (2a) and when lift- ed (2b) in connection with a tractive unit, such as a forklift truck,

Figure 3 shows stages of applying the principle of self-loading and self-unloading using the method according to the invention and the lifting transport trailer with the mecha¬ nism shown in Figs. 1 and 2a, 2b, and

Figs. 4-6 show schematically some alternative embodiments of the lifting transport trailer according to the invention, par¬ ticularly the construction of the lever mechanism,

Fig. 7 shows phases (a-1) of the method and use of the lifting transport trailer according to the invention in handling of inter¬ changeable containers equipped with standing legs on a support bottom as seen from the side, and

Fig. 8 shows a schematical side view of the operation of a spring-loaded limiter means

used in the lifting transport trailer according to the invention in different positions of the liftingtransport trailer.

5 In the following, the theoretical basis of the method according to the invention is illustrated- with refe¬ rence to Figs. 1, 2a and 2b particularly to describe the factors on the quantity of the moments applying at the point of articulation between the second lever 10 frame and the frame.

According to the notations in Fig. 1, the condition for the balance of the lever mechanism is

15 T = T ₂ , (1)

further, the condition for the moment balance around point P

20 F ₂ * b ₂

^F l * ^b l ~ l * ^b 2 ⁼ ° ^=> l ⁼ ( ² )

and the condition for the moment balance around point Q

25

F ₂ * Sj

F ₂ * a _! - T ₂ * a _x = 0 => T ₂ = , (3) ^a 2

30 (2) and (3) being substituted in the equation (1) , it follows that:

F-L * b _x F ₂ * a ₂ = (4)

35 b ₂ a _] _

If Tτ_ < T , point K rotates counterclockwise in relation to point P and point S rotates clockwise, in relation to point Q. 40

If T^ > T , point K rotates clockwise in relation to point P and point S rotates counterclockwise in relation to point Q.

Further, using the notations in Fig. 2a, the condition for balance is

^G 0 ^* " ^F 01 ~ ^F 02 ⁼ ° ^{=> F} 01 ^{= G} 0 ~ ^F 02' ( ⁵⁾

wherein the condition for moment balance around point K is

* It

02 * L - G _n * In = 0 => 02 (6)

when (5) and (6) are combined, it follows that:

G ₀ * 1Q F ₀₁ = G ₀ (7)

When unloaded, the equations FQI = F^ and F _Q2 = F ₂ are in force; thus (6) and (7) can be substituted in the equation (4) , whereby it follows that

1 ₀ ]_ 1 ₀ * a ₂ 1 ) * = (8)

L b ₂ L * a^L

Consequently, the operation according to the invention being generated without loading so that the lever frame N of the rotating organ rotates counterclockwise around point P towards the limiter means Rl so that the lever frame N and thus the carrying plane is placed at the point of the rotating organ in the lowest position in relation to the bottom, the factors involved are presented in the inequality statement (9) .

lo ^b l ^a 2

(1 ) * — < (9 )

L * a^

Using the notations of Fig. 2b and the equation (8) , it follows that:

!tot ^b l ^x tot * ^a 2 , _ΛX (1 ) * — = (10)

L b ₂ L * a^

Furthermore, it is noted that

G _tot = G + G ₀ (11)

and

(G ₀ * 1 ₀ + G * 1) l _tot = (12)

^G tot

Consequently, the operation according to the invention when loaded being generated so that the lever frame of the rotating organ rotates clockwise around point P towards the limiter means R ₂ and the lever frame N is placed at the point of the rotating organ at the uppermost position in relation to the bottom, the factors involved are presented in the inequality statement (13), which is a combination of the equations (10) to (12) .

G ₀ * 1 ₀ + G * 1 b-L G ₀ * 1 ₀ + G * 1

(1 ) * — > * a ₂ L * G _tot b ₂ L * G _tot * a _x

(13)

Thus, it is a requirement for the operation of the lifting transport trailer that when substituted, the factors selected fulfill the inequality statements (9)

and (13) simultaneously. The notations used hereabove are presented in a list at the end of the description.

With particular reference to Figs. 2a and 2b, the lifting transport trailer according to the invention has a frame u; the first lever frame M is- fixed with a horizontal joint Q to one end of the frame u. As illustrated in Figs. 2a, 2b and 3, the first lever frame M, seen from the side, has a downwards directed U-shape, particularly when the lifting transport trailer is in the first position according to Fig. 2a. The first arm part VI of the first lever frame M is shaped as a shaft, wherein the free end of the same is equipped with an attachment device, such as an articulated bushing-type coupling means H for connect¬ ing the fork part of a forklift TR performing a vertical movement to the lifting transport trailer. In the embodiment shown in Figs. 2a, 2b and 3, the middle section of the second arm part V2 of the first lever frame M is connected to a joint Q. Further, a power transmission organ VE is connected with joint Ml to the free end of the second arm part V2. In the embodiment shown, this organ VE is a bar or wire cable articulated between the joint points Ml and Nl in the longitudinal direction of the frame. The joint point Nl is formed between the power transmission organ VE and the second lever frame N. The second lever frame N, then, is articulated with joint P to the bracket support connected to the frame part RO directed downwards from the carrying plane KT of the frame u. Furthermore, at least one rotating organ PE is mounted in bearings at the bearing point K to connect with the second lever frame N. The embodiment of the lifting transport trailer according to Figs. 2a, 2b and 3 being in its first position, i.e. the lower posi¬ tion, the part Rl in the downwards directed frame part RO functions as the first limiter means (limiter means Rl) . The second lever frame N has a triangular

shape, in which case the said joints Nl, P and K are placed at the corners of the triangular shape.

Furthermore, a second limiter means R2 is formed in the frame by a bracket support directed downwards from the carrying plane KT of the frame u for•the second position, i.e. the upper position, of the presented embodiment of the lifting transport trailer.

The use of the embodiment of the lifting transport trailer according to Figs. 2a and 2b as an application of the self-loading and self-unloading principle is particularly shown in stages in Fig. 3. Fig. 3a shows the stage of shifting the lifting transport trailer from the bottom under the load KK lifted by means of a support device TL. The fork of the forklift TR is used to rotate (around the bearing point K) the unloaded lifting transport trailer in its first position upwards counter-clockwise, as shown in Fig. 3b, until the carrying plane KT meets the load KK and/or the support device TL, and the lifting transport trailer is shifted to the second position in the manner described above, as shown in Fig. 3c. Further, the rotation of the lifting transport trailer as a stiff body is continued in its second position to the position shown in Fig. 3d to make the carrying plane KT horizontal, so that the forklift TR can carry the combination of the load KK and the support device TL.

Figs. 3e to 3g show the corresponding measures in connection with unloading the load KK and the support device TL from the carrying plane of the lifting transport trailer. These stages are essentially reverse to those described above.

Fig. 4 shows an embodiment of the lifting transport trailer, in which a release spring KJ is placed in the lifting transport trailer corresponding to that

presented above. The release spring KJ is placed so that its force will further the shifting of the lifting transport trailer from the second position to the first position, i.e. the lower position, shown in Fig. 4. A release spring KJ of this kind can be placed in one or several points in the construction. In the embodiment shown in Fig. 4, it is placed between the frame u and the joints Q and Ml in the second arm part of the first lever frame M.

Fig. 5 shows an alternative embodiment, in which the places of the joints Ml and Q as well as the direction of rotation of the second lever frame N have been changed. For this purpose, a downwards directed bracket support has been formed in the front section of the frame u, in which the said joint Q is made.

Fig. 6 shows an embodiment of the power transmission organ VE which uses pressure medium. For this purpose, pressure-medium operated cylinder-piston combina¬ tions SMI and SM2 are connected in the solid, downwards directed bracket supports in the frame u and in the lever frames M and N, respectively, in which the closed circulation of pressure medium is arranged so that the first cylinder-piston combination SMI being in its shortest length, the second cylinder-piston combination SM2 is in its greatest length correspond¬ ingly. This method is used to effect the operation shown in Figs. 2a and 2b.

Some embodiments of the lifting transport trailer according to the invention were presented above, but with reference to what was presented, it should be clear for an artisan in the field that also several other applications are feasible. For example in Fig. 4, a mechanism PS is presented for shifting the centre of gravity of the frame u so that the lifting transport trailer can be shifted from the first position shown

in Fig. 4 to the second position also when unloaded. The mechanism for shifting the centre of gravity may comprise a mass unit MY which is movable in the groove UR or the like in the longitudinal direction of the frame u and whose shifting to the right in the said groove UR in Fig. 4 makes it possible to shift the lifting transport trailer to the second position. Furthermore, it is clear that with reference to the inequality statements (9) and (13) , also the lever relations aτya ₂ and b ₁ /b ₂ can be changed. In the simplest manner, this can probably be done by changing the lever relation a ₂ , in which case the first arm part VI of the first lever frame M with U-form can be made to have e.g. a telescopic structure.

With particular reference to Fig. 7, the method according to the invention can further be applied to lifting in two phases. In the first phase shown in Fig. 7a, the first lever frame M of the lifting transport trailer is connected to a working machine, such as a forklift truck TR as shown in the figure. After this, the lifting transport trailer, which is in its lower position on the support of the forklift truck, is shifted under the support bottom 1 as shown in Fig. 7b. The support bottom 1 comprises the carrying plane la and the support leg arrangement lb in connec¬ tion with the same. The lifting transport trailer is placed particularly under the support level la of the support bottom 1, between the support leg arrange- ment lb. Thus the fork part of the forklift truck TR is lifted upwards, as shown in Fig. 7c, wherein the lifting effect is directed also to the first lever frame M and the carrying plane KT in the frame u of the lifting transport trailer is lifted upwards as described above. Thus in the situation shown in Fig. 7e, the support bottom 1 is entirely above the carrying plane of the frame u of the lifting transport trailer, in its first lifted position zone. The support

leg arrangement lb is loose from the bottom. Thus according to Fig. 7f, the lifting transport trailer and the support bottom 1 lying on the support of the frame u of the same can be lifted together by a forklift truck under the load, such as an inter¬ changeable container KK supported by the support apparatus, such as the standing legs TL, in the functional position. The placement is advantageously performed between the standing legs TL of the inter- changeable container KK in the longitudinal direction of the interchangeable container KK. After this, further steps are taken to the situation shown in Figs. 7g and 7h, in which the fork part of the forklift truck TR is lifted and thus a vertical force is effective on the lever frame M of the lifting transport trailer in a manner as described above, thus lifting the carrying plane KT of the frame u of the lifting transport trailer further, resulting in a situation as shown in Fig. 7i, in which the support bottom 1 and the interchangeable container KK above the same are in the second lifted position zone. The standing legs TL of the interchangeable container KK are thus loose from the bottom. Consequently, the interchange¬ able container KK lies substantially on the support of the lifting transport trailer by means of the support bottom 1. As shown in Fig. 7i, the standing legs TL of the interchangeable container KK are placed in a non-functional position, e.g. in the direction of the bottom of the interchangeable container KK. Normally, there are four standing legs, placed at the corners of each longitudinal side of the interchange¬ able container KK. In moving the standing legs to the non-functional position, it is essential that they are above the lower edge of the support leg arrangement la of the support bottom 1. Thus, as shown in Fig. 7j, the combination 1, KK can be shifted e.g. to the phase of loading or unloading goods TP by a forklift truck TR, as shown in Fig. 71, or to the transport

phase, and the fork of the forklift truck TR can be lowered, wherein the first lever frame M of the lifting transport trailer is shifted downwards and the carrying plane KT of the frame u is similarly lowered, wherein the support bottom 1 and the interchangeable con¬ tainer KK on the same, supported by the standing leg arrangement TL, are placed against the bottom, the lifting transport trailer reaching the lowest position. From the presentation above, the next phases of the operations are clear to an artisan in the field. Consequently, e.g. a situation shown in Fig. 7b corresponds to a situation in which the operations are continued after the work phase shown in Fig. 71, wherein the steps 7d to 7e are taken, however, the interchangeable container KK lying naturally on the support bottom 1; after this, the step as shown in Fig. 7i is taken in the reverse order, i.e. the standing legs TL are moved to the functional, erected position, and, as shown in Fig. 7k, the frame of the lifting transport trailer is lowered to the first lifted position zone and the combination of the lifting transport trailer and the support bottom lying on the same is shifted away from below the interchangeable container KK supported by the standing legs TL.

With particular reference to the advantageous embodi¬ ment shown in Fig. 7, Fig. 8 illustrates the structure and operation of the functions according to Fig. 7 in different phases. In principle, the lifting transport trailer comprises organs for adjusting the height level of the upper position of the frame u on two or more levels. Functioning as the said organ in connec¬ tion with the second lever frame N and/or the second limiter means R2, there is a pressure spring PJ or the like with a spring constant rated and/or adjusted by adjusting organs (not presented here as a technical application obvious to an artisan in the field) for achieving at least two zones of upper position depend-

ent on the load of the lifting transport trailer. Fig. 8a shows a situation, in which the lifting transport trailer is in the lower position zone, the second lever frame N being placed towards the first limiter means Rl. Shifting to the first lifted position zone, the situation is shown in Fig. 8b (cf. Figs. 7e and 7f) . Further, Fig. 8c shows a situation according to the second lifted position zone (cf. Figs. 7i and 7j) . The pressure spring PJ is placed between the second lever frame N and the second limiter means R2 and connected to the second limiter means R2 in a manner that during rotation, the second lever frame N meets the said pressure spring PJ and directs a pressure load to the same, wherein the pressure spring PJ is pressed together, thus increasing the force resisting the rotation, and in a balance situa¬ tion, the force by the pressure spring PJ directed to the second lever frame N being sufficiently great to stop the rotation of the lever frame, the carrying plane of the frame of the lifting transport trailer and the support bottom above the same are in the first lifted position zone. From the situation shown in Fig. 7b, the interchangeable container KK being placed above the support bottom 1, the rotation of the second lever frame N continues with an increase in the load furthering the rotation of the lever frame N, the interchangeable container being placed on the support bottom.

Explanations of the notations used:

T^ = force of support reaction of the power transmission organ (VE) on the second lever frame (N) ,

T ₂ = force of support reaction of the power

transmission organ (VE) on the first lever frame (M) , "

^F l _r ^F ₀ 1 ⁼ vertical force of support reaction between the rotating organ (PE) and the bottom,

^F 2' ^F ₀ 2 ⁼ vertical force of support reaction on the first lever frame,

G _Q = weight of the lifting transport trailer,

G = weight of the load KK,

^G tot = G ₀ + G,

L = the horizontal distance between the forces * , F ₀₁ and F ₂ , F ₀₂ ,

1 ₀ = the horizontal distance between the centre of gravity of the lifting transport trailer and the point of application of the force

1 = the horizontal distance between the common centre of gravity of the load and the lifting transport trailer and the point of application of the force F _] _, Fgi,

a^ = the shortest distance between the points of articulation between the power trans¬ mission organ and the first lever frame and between the frame and the first lever frame,

a ₂ = the shortest distance between the line of application of the force F , F ₀ and the point of articulation between the frame and the first lever frame,

bi = the shortest distance between the point of articulation between the frame and the second lever frame and the line of applica-

5 tion of the force F _lf F ₀ applying to the rotating organ,

b = the shortest distance between the points of articulation between the frame and the

10 second lever frame and between the power transmission organ and the second lever frame.