GB2278337A

GB2278337A - Spreader guide apparatus

Info

Publication number: GB2278337A
Application number: GB9410317A
Authority: GB
Inventors: Wang-Sun Heo; Young-Suk Kim
Original assignee: Samsung Heavy Industries Co Ltd
Current assignee: Samsung Heavy Industries Co Ltd
Priority date: 1993-05-27
Filing date: 1994-05-23
Publication date: 1994-11-30
Anticipated expiration: 2014-05-23
Also published as: SE9401120L; GB9410317D0; SE9401120D0; SE507906C2; JPH07137983A; GB2278337B; DE4411579A1

Description

2278337 SPREADER GUIDE APPARATUS FOR A CRANE is The present invention

relates to a spreader guide apparatus for a crane which is capable of loading a container accurately and quickly to a desired position.

Since the highest level of stacked containers is gradually increased due to the increase in the number of containers to be transported in recent years, it has been necessary to load each container accurately in its desired position, in order to prevent interference between the containers, and to ensure the stability of the loaded containers.

In general, the operation for loading containers includes the use of a spreader, with a container hung therefrom, which moves horizontally to a loading position by the movement of a trolley mounted on a crane and thereby loads the container at the position. In this case, it is difficult to position accurately the container at the loading position, because the operation room of the crane is too far from the loading position, and the container hung on the trolley is influenced by external forces, such as wind, and the inertial force caused by the horizontal movement of the trolley. Hence, the expertness of the operator is required to load the 2 containers accurately at the desired position.

Furthermore, even when the skilled operator carries out the loading operation, quite a time is required and it is difficult to position accurately the containers at the loading position.

In the stack of containers loaded by the above- mentioned conventional loading manner, though the containers positioned at the lower side of the container pile may not provide a problem, the containers positioned at the upper side may interfere with another container resulting in a risk of collapse because of an error in is positioning the upper containers.

Various methods have been proposed in order to overcome the above-mentioned problems, but the proposed methods have not been sufficiently good to be applied in actual operation.

In an example of a conventional method, a recognition camera attached to a trolley reads the position of a container to be loaded and then transfers the container at a distance deviated from the accurate position according to the result of the position read.

However, since the ability of the recognition camera to function is liable to deterioration because the recognition camera is influenced by weather, for example when used on a rainy day, or a snowy dayf and by darkness at night, the apparatus cannot be used in all weathers. and at all times.

In another example in which an antenna type touch sensor, instead of a recognition camera, is used to sense the position of a loaded container, the touch sensor may malfunction frequently and the antenna used as the touch sensor may be easily damaged, thereby reducing its operating efficiency.

In the case of still another example, in which a mechanical guide provided at the sides of a spreader is used to guide an upper container on to a lower container and thus to adjust the relative position between the two adjacent upper and lower containers, since elongated guide arms are disposed at the sides of the spreader, much time is required to guide a container and the guide arms are liable to interfere with another container.

Referring to Fig. 1, there is shown a conventional transfer crane supported on the ground. A loading operation carried out by a transfer crane 1 for loading containers 2 into a number of stories will now be described with reference to the drawing.

A container 2 carried on a trailer 6 is attached to a spreader 3. The spreader 3 from which the container 2 is suspended can be raised and lowered by a rope 4 connected between the spreader 3 and a trolley 5. As the trolley 5 mounted on the transfer crane 1 is moved horizontally. the spreader 3 suspended from the trolley 5 by the rope 4 is moved horizontally, so that the container 2 suspended from the spreader 3 can be moved to a desired loading position.

After the spreader 3 has been moved to the desired position, the spreader 3 is lowered by the rope 4 and releases and loads the container 2 accurately at the desired loading position. The above-described loading operation is carried out as a result of a series of operations controlled by an operator in an operation room 7 which is moved together with the trolley 5.

However, since the operation room 7 is far from the loading position and the spreader 3 is influenced by the force of the wind and the inertial force caused by the horizontal movement of the spreader 3. it is not easy to load the container 2 accurately at the loading position and also much time is required to search for the correct loading position, thereby reducing the work efficiency.

One feature of the present invention is the provision of a link type spreader guide apparatus which is capable of easily searching for a loading position and stably loading containers by guiding a spreader, so that it is possible to shorten the time required to position a load and improve the work efficiency.

Another feature of the invention is the provision of a link type spreader guide apparatus including a link type driving system capable of reducing the possibility of deformation caused by external forces and operating even when a slight deformation is generated, and hardly generating frictional resistance, thereby achieving an easy maintenance without the need for a lubricant.

Yet another feature of the invention is the provision of a link type spreader guide apparatus capable of being vertically turned over on a spreader, thereby achieving easy and smooth loading and unloading operations for containers particularly in the case in which a trailer is used for carrying containers two stories high, without interference with the trailer.

In an embodiment to be described below there is a spreader guide apparatus which includes an upper structure mounted on a spreader and having driving means at both its sides, the driving means having a pulley and a rope wound on the pulley; a lower structure connected to a free end of the rope and adapted to be raised and lowered by the operation of the driving means, the lower structure being provided at its lower corner portions respectively with flippers for guiding the spreader and provided at both its sides respectively with clamp means for coupling a container thereon; and an extendable link mechanism connected between the upper structure and the lower structure.

Embodiments of the invention will now be described, 6 which are given as examples, with reference to the accompanying drawings in which:

Fig. 1 is an schematic elevation view showing a 5 conventional transfer crane; Fig. 2 is a schematic front view of a spreader guide apparatus according to a first embodiment of the present invention; Fig. 3 is a schematic view illustrating a link mechanism constituting a part of the spreader guide apparatus according to the present invention; Fig. 4 is an enlarged cross-sectional view of the circle "B" in Fig. 2; Fig. 5 is a cross-sectional view taken along line A-A in Fig. 2; Fig. 6 is an enlarged cross-sectional view of the circle "C" in Fig. 5; Fig. 7 is a perspective view of a stopper of an assistant link constituting a part of the spreader guide apparatus according to the first embodiment of the invention; Fig. 8 is a perspective view illustrating an operation of the spreader guide apparatus according to the first embodiment of the invention; Fig. 9 is a schematic front view of a spreader guide apparatus according to a second embodiment of the present 7 invention; Fig. 10 is a schematic front view of a spreader guide apparatus according to a third embodiment of the present invention; Fig. 11 is a longitudinal cross-sectional view of a 5 three-step telescopic member shown in Fig. 10; Fig. 12 is a front view of a spreader guide apparatus including turnover means according to a fourth embodiment of the present invention; Figs. 13a to 13c are side views respectively illustrating different operations of the spreader guide apparatus in accordance with the fourth embodiment, wherein Fig. 13a corresponds to a normal condition, Fig. 13b a condition ready for a turnover operation, and Fig. 13c a condition after completion of the turnover operation; Fig. 14 is a schematic side view illustrating the turnover operation of the spreader guide apparatus in accordance with the fourth embodiment; Fig. 15 is a schematic side view of turnover means according to a fifth embodiment of the present invention; and Fig. 16 is a schematic side view of turnover means according to a sixth embodiment of the present invention.

is 0 1 0 8 1 0 Referring to Fig. 2, there is shown a side of a spreader guide apparatus according to a first embodiment of the present invention which is mounted on front and rear sides of a spreader. In this drawing, a solid line illustrates a condition in which the spreader guide apparatus is retracted and a phantom line illustrates a condition in which the spreader guide apparatus is extended.

Fig. 4 shows a cross-section of a circle "B" of the spreader guide apparatus shown in Fig. 2.

As shown in Figs. 2 and 4, the spreader guide apparatus according to the first embodiment of the present invention comprises upper structures 10 mounted on front and rear sides of a spreader 3, each of which is provided at its both sides with driving means including a driving motor 12 connected to a pulley 11 for taking up a rope 14, and lower structures 13 each connected to each corresponding upper structure 10 by the rope 14 interposed therebetween and adapted to be raised and lowered by the rope 14 winding on and unwinding from the pulley 11 by the driving motor 12. Each lower structure 13 is provided with flippers 15 respectively attached on both sides of the bottom surface of the lower structure 13. Each lower structure 13 also has clamp mechanisms 16 (Fig. 6) therein. The spreader guide apparatus further comprises 1.

9 is extendable link mechanisms 17 each connected between each corresponding upper structure 10 and each corresponding lower structure 13.

Each link mechanism 17 comprises main link members 17a connected with one another into a scissors shape and assistant link members 17b connecting the main link members 17a to the upper and lower structures 10 and 13. The distance a defined between facing assistant link members 17b and shown in Fig. 3 is preferred to be as wide as possible in order to enhance the stability against the forward and rearward movements of the lower construction. The optimum length L1 of each assistant link member 17a and the distance a are determined by the following equations:

i) a + 2Licos@1 = L2COS@2 ii) h/2 = L2sinf32 + Lisinei iii) Lisin@l + Licoseitank32 > link width + 10 (hmin) iv) et < 90x (h.ax) wherein, L2 represents the length of each main link member 17a, h represents the height of the extended link mechanism 17, hmin represents the height of the retracted link mechanism 17, hmax represents the height of the fully extended link mechanism 17, f31 represents the maximum extended angle of each assistant link member 17b, and @2 represents the maximum extended angle of each main link member 17a. The equation M stands for a condition wherein the assistant link members 17b is do not interfere with the main link members 17a when the spreader guide apparatus moves to its retracted position. On the other hand, the equation iv stands for a condition wherein the maximum extended angle @i of each assistant link member 17b exceeds 90x when the spreader guide apparatus is at its fully extended position. The factors L2, hmin and hmax are determined depending on the design implemented.

It is preferred that the length Li of each assistant link member 17b corresponds to 1/3 to 2/3 of the length of each main link member 17a.

By virtue of the assistant link members 17b in the particular embodiment, the spreader guide apparatus does not involve any sliding movements of the main link members on the upper and lower structures. In the conventional apparatus wherein main link members are directly connected to the upper and lower structures, the main link members should be constructed to slide on the upper and lower structures. Since the spreader guide apparatus of the present embodiment requires no sliding movement of the main link members on the upper and lower structures, it enables easy maintenance, an enhanced durability and a lengthened 1 to be obtained.

As shown in Fig. 7, each lower structure 13 includes stoppers 17c respectively provided near its portions on which the assistant link members 17b are mounted. The stoppers 17c serve to limit the extension of the link mechanism 17 to a is predetermined angle.

As best seen from Fig. 4, each upper structure 10 includes upper supporters 36 fixedly mounted on both ends of the upper structure 10 and adapted to f irmly support the spreader guide apparatus positioned at the retracted position so as to prevent the link mechanism from being subjected to a deformation such as bending due to lateral movements or swing thereof. Each upper supporter 36 includes an insert pin 362 resiliently supported by a compression coil spring 361. On the other hand, each lower structure 13 includes lower supporters 37 f ixedly mounted on both ends of the lower structure 13 and adapted to receive corresponding upper supporters 36 at the retracted position of the spreader guide apparatus.

At the lower surface of each lower structure 13, a position sensor 13a such as a photosensor is provided which serves to sense a stopped position of each lower structure 13 corresponding to the lower end of a subject container in the extending operation and the lower end of the spreader in the retracted operation.

In order to ensure the stability of the spreader guide apparatus in accordance with the present embodiment the clamp mechanisms 16 are provided which are adapted to be engaged in corner holes 2a formed at the container 2, respectively.

Fig. 5 shows a cross-section taken along a line A-A in 12 is Fig. 2, and Fig. 6 shows an enlarged fragmentary cross-section of Fig. 4. The clamp mechanism 16 of each lower structure 13 includes a hydraulic cylinder 18 and a clamper 19 which is projected into and retracted from the corresponding corner hole 2a of the container by the operation of the hydraulic cylinder 18. The clamper 19 is resiliently supported by a compression coil spring 191.

Referring to Fig. 8, there is shown a perspective view of the link type spreader guide apparatus In accordance with the first embodiment of the present invention. Now, operation of the spreader guide apparatus will be described in conjunction with Fig. 8.

Before the container 2 is hung from the spreader guide apparatus of the embodiment, the link type spreader guide apparatus is in a retracted conditiont that is, the lower structure 13 is adjacent to the upper structure 10 (as illustrated by the solid line in Fig. 2 and denoted by the arrow "I" of Figs. 8 and 13a) In order to raise the container 2, the spreader 3 is horizontally moved to a position above a predetermined position of the container 2 by movement of the trolley 5 and then lowered to the predetermined position of the container 2. When the spreader 3 is located just above the container 2, the flippers 15 attached to the lower structure 13 guide the spreader 3 such that the spreader 3 is accurately mounted on 13 is the container 2. After the container 2 is hung from the spreader 3, the spreader 3 carrying the container 2 is raised by the rope 4 and moved to a desired loading position by movement of the trolley 5 where the spreader 3 is ready to load the container 2 onto another container 2' which has been previously positioned on the pile.

During the above-described operation for loading a container 2 onto another piled container 2', the link type spreader guide apparatus of the embodiment is extended to guide the container onto the piled container 2'. That is, when the container 2 is located at a certain position above the previously filed container 2', the rope 14 is unwound from the pulley 11 upon energizing the driving motor 12 so as to move the container 2 downward. As a result, the lower structures 13 connected to the rope 14 are lowered while the link mechanism 17 is extended downward. At this time, the position sensor 13a senses the lowered position of the link mechanism 17. When the link mechanism 17 is completely extended, the driving motor 12 is stopped and thus the downward movement of each lower structure 13 is completed (as illustrated by the phantom line and denoted by the arrow "III' of Fig. 8).

When the link mechanism is extended, the position thereof where the drive motor 12 is stopped corresponds to the position of the corner holes 2a of the container 2 hungfrom the 14 spreader. When the link mechanism is retracted, the position thereof where the drive motor 12 is stopped corresponds to the position of the holes, not shown, of the spreader. As mentioned above, the extension of the link mechanism 17 is limited by the stoppers 17c provided at the lower 5 constructions 13.

After completion of the downward movement of the spreader guide apparatus, the clamp mechanism 16 of each lower structure 13 begins to operate. As the hydraulic cylinder 18 of each clamp mechanism 16 is activated, the clamper 19 connected to the hydraulic cylinder 18 is forced to be moved inwardsand thus inserted into the corresponding corner hole 2a formed at the lower corner portion of the container 2, as illustrated in Fig. 5. Therefore, the lower structures 13 are fixedly coupled with the container 2, so that stability of the extended spreader guide apparatus can be enhanced.

After the lower structures 13 are fixedly coupled with the container 2 as described above, the spreader 3 carrying the container 2 is raised by the rope 4 and moved to a desired loading position where the spreader 3 is again lowered onto the piled container 2'. At this time, since the flippers 15 attached to the lower structure 13 come into contact with upper corners of the container 2' at inner surfaces thereof while being lowered, the lower structure 13 and thus the container 2 are accurately and quickly positioned onto the container 2'. That is, the container 2 can be easily loaded 0 is onto the filed container 2' by the guiding function of the flipper 15 to extent similar to when the container 2 is hung to the spreader 3 and raised.

When the container 2 is positioned and loaded onto the previously piled container 2' as described above, the clamper 19 of each clamp mechanism 16 is pulled out of the corresponding corner hole-2a formed at the lower corner portion of the container 2 by activation of the hydraulic cylinder 18 and then the rope 14 is wound on the pulley 11 by activation of the driving motor 12. Hence, each lower structure 13 is raised upward while the link mechanism 17 is retracted. Thereafter, the spreader 3 is separated from the container 2, thereby completing the container loading operation.

Fig. 9 is a schematic front view of a spreader guide apparatus in accordance with a second embodiment of the present invention. The spreader guide apparatus of the second embodiment is similar to that of the first embodiment with regard to the use of link mechanisms connecting the upper structures with the lower structure, but different from the first embodiment with regard to the constitution and connecting construction of link mechanisms used.

In accordance with the second embodiment of the present invention, the spreader guide apparatus includes link members 170 connected with one another into a scissors shape between 1 4.

16 the upper and lower structures 10 and 13. The upper end 170a of one of the uppermost link members 170 is pivotally mounted to the upper structure 10 whereas the upper end 170a' of the other uppermost link member 170 is slidably disposed in a slide groove 10a formed at the upper structure 10. In similar, the lower end 170b of one of the lowermost link members 170 is pivotally mounted to the lower structure 13 whereas the lower end 170b' of the other lowermost link member 170 is slidably disposed in a slide groove 10a formed at the 10 lower structure 13. In place of the rope 14 used in the case of the f irst embodiment, a chain 140 is used in accordance with the second embodiment. When the spreader guide apparatus of the second 15 embodiment is to be extended and retracted, it operates in the same manner as that of the first embodiment, except that the ends 170a' and 170b' of the link members 170 slide in the slide groove 10a and 13a, respectively. Accordingly, detailed description of the operation will be omitted. 20 Figs. 10 and 11 show respectively a telescopic type spreader guide apparatus according to a third embodiment of the present invention in which the link mechanism is replaced with a telescopic member. As shown in the drawings, the telescopic type spreader guide apparatus includes three-step 25 telescopic members 20 respectively fixed to four corners of a spreader 3 and lower structures 13 respectively fixed to lower ends of each pair of the telescopic members 20. Each lower structure 13 has a f lipper 15 and a clamp mechanism both similar to those of the first embodiment.

Each three-step telescopic member 20 comprises a first connecting member 21 fixed to the spreader 3, a second connecting member 22 slidably inserted in the first connecting member 22 and a third connecting member 23 slidably inserted in the second connecting member 22. The third connecting member 23 is attached at its lower end to the lower structure 13 with flippers 15 attached thereto.

As illustrated in Fig. 11, the third connecting member 23 of the threestep telescopic member 20 includes a hydraulic cylinder 24 and a driving chain 26 therein.

The hydraulic cylinder 24 is fixed at its upper end to an upper end of the first connecting member 21 and fixed at its piston rod to a lateral projection of an L-shaped connection bar 27. The connection bar 27 is provided at both ends with sprockets 28, and the sprockets 28 are engaged with the chain 26. Connected between both ends of the chain 26 are buffer means 29 such as springs, and the springs 29 are fixed to a lower end of the hydraulic cylinder 14. The chain 26 is connected to the third connecting member 23 by means of a connection plate 30 secured therebetween.

Operation of the telescopic type spreader guide apparatus .. 4 18 1.

according to the third embodiment of the invention will now be described in detail.

When the telescopic type spreader guide apparatus loads a container 2 onto a previously piled container V, the three- step telescopic members 30 are extended downward in order to guide the container 2 toward the container V.

As the hydraulic cylinder 24 in each three-step telescopic member 20 is activated, the piston rod of the hydraulic cylinder 24 is downward moved. Since the buffer means 29 connected to the two ends of the chain 26 are f ixed to the hydraulic cylinder 24, the chain 26 and the sprockets 28 are lowered while being rotated in the direction of an arrow E of Fig. 9. Consequently, the connection plate 30 secured between the chain 26 and the third connecting member 23 is moved downward along with the chain 26, so that the third connecting member 23 can be moved downwards. As a result, the three-step telescopic member 20 is extended. A retraction operation of the telescopic member 20 is carried out in a reverse manner to the above-described extension operation.

After the three-step telescopic member 20 has been extended in the manner described above, the clamper 19 of the clamp mechanism is inserted into the corresponding corner hole 2a of the container 2 to improve stability of the telescopic member 20.

-1 19 is Thereafter, the spreader 3 carrying the container 2 is raised and horizontally moved to a desired loading position. The container 2 is again lowered onto the previously piled container 2' while being guided to the piled container 2' by the flipper 15. After the container 2 is accurately loaded onto the piled container 2', the clamper 19 of the clamp mechanism is retracted from the corner hole 2a of the container 2. Then, the three-step telescopic member 20 is retracted by the retraction action of the hydraulic cylinder 24, thereby completing the container loading operation.

Referring to Fig. 12, there is shown a spreader guide apparatus according to a fourth embodiment of the invention. Although the spreader guide apparatuses of the above-mentioned embodiments are suitable to load and unload a container in case of a trailer for carrying container into one story, they are impossible to load and unload a container in case of a trailer for carrying containers into two stories, namely, a double stack trailer. This is because the spreader guide apparatus interferes with a fence guide "F" (see Fig. 1). Therefore, the fourth embodiment of the invention is designed to overcome the above-mentioned problem.

As illustrated in Fig. 13a, the spreader guide apparatus includes a turnover means 35 for turning the spreader upward. The turnover means 35 comprises a driving motor 32 supported on a bracket 31 secured to the spreader 3 and a turnable 9.

connection arm 34 which is connected at one end thereof to a driving shaft 33 of the driving motor 32 and connected at the other end thereof to the upper structure 10 supporting the spreader guide apparatus.

When the spreader guide apparatus of the third embodiment loads in or unload from the trailer for carrying container into one story, the link mechanism of the apparatus is extended downward and retracted upward, as shown in Fig. 13a.

In case of the double stack trailer for carrying trailers into two stories, the spreader 3 is upward turned over by the turnover means 35 in order to prevent the apparatus from being interfere with the fence guide "F", as shown in Fig. 13c.

In other words, when the spreader 3 loads in or unloads from the trailer for carrying trailers into two stories, the link mechanism 17 of the spreader guide apparatus is retracted from the condition shown in Fig. 13a so that the upper supporter 36 mounted on the upper structure 10 is fixedly engaged with a lower supporter 37 mounted on the lower structure 13 as shown in Fig. 13b. Thereafter, upon activating the driving motor 32 mounted on the spreader 3, the connection arm 34 connected to the driving shaft 33 of the driving motor 32 is turned upward so that the spreader guide apparatus fixed to the lower end of the connection arm 34 is turned over in the direction of an arrow "R" of Fig. 14.

Accordingly, the spreader guide apparatus is positioned above 21 the spreader 3 as shown in Fig. 13c, thereby preventing the spreader guide apparatus from interfering with the fence guide "F" of the double stack trailer.

Since the driving motor 32 always rotates in a direction indicated by an arrow L of Fig. 14 in the normal operation shown in Fig. 13a, the spreader guide apparatus is prevented from being separated from the spreader and the container due to the inclination or the swing of the container and from being damaged due to an excessive external force generated during the upward and downward movements thereof.

Fig. 15 shows a spreader guide apparatus including turnover means according to a fifth embodiment of the invention.

As shown in Fig. 15, the turnover means 35' of the fifth embodiment is of a geared drive type including a connecting rod 34' attached at one end thereof to each upper structure 10 and pivotally mounted on a shaft 36' fixedly mounted to a bracket 31 fixedly mounted to the spreader 3, a driven gear 37' provided at one end of the shaft 36', and a driving gear 38 engaged with the driven gear 37' and driven by a drive motor 32. The driving gear 32 is supported by the bracket 31 of the spreader 3.

The turnover means 35' of this case operates in the same manner as that of the fourth embodiment and, thus, its detailed description will be omitted.

1 0 22 Fig. 16 shows a spreader guide apparatus including turnover means according to a sixth embodiment of the invention. As shown in Fig. 16, the turnover means 35" of the sixth embodiment is of

a chained drive type including a connecting rod 34' attached at one end thereof to each upper structure 10, a driven sprocket 37" provided at one end of the other end of the connecting rod 3C, and a driving sprocket 38' connected with the driven sprocket 37" by means of a chain 39 and driven by a drive motor 32.

The turnover means 35" of this case operates in the same manner as that of the fourth embodiment and, thus, its detailed description will be omitted.

As will be apparent there has been described a spreader guide apparatus including a link type operating construction capable of involving less possibility of deformation caused by external force and operating even when a slight deformation is generated, and hardly generating frictional resistance, thereby achieving an easy maintenance without a need of lubricant. Since the spreader guide apparatus is firmly kept on the container by the clamp mechanisms, it is prevented from being separated from the spreader and the container due to the inclination or the swing of the container and from being damaged due to an excessive external force generated during the upward and 0 23 downward movements thereof. Furthermore, the spreader guide apparatus can accurately and quickly position a container to a desire loading position, thereby improving work efficiency and stability of the piled containers - In addition, since the spreader guide apparatus of the invention can be turned upward by the turnover means, it is possible to avoid interference between the spreader guide apparatus and a fence guide of a trailer.

It must be understood that many alterations and modifications may be made by those having ordinary skill in the art to the structures disclosed herein without departing from the scope of the invention as defined in the appended claims. Therefore, the presently illustrated embodiments have been shown only by way of example and should not be taken to limit the scope of the following claims.

D 0 24

Claims

1. A spreader guide apparatus comprising:

an upper structure mounted on a spreader and having driving means at its both sides, the driving means having a pulley and a rope wound on the pulley; a lower structure connected to a free end of the rope and adapted to be raised and lowered by an operation of the driving means, the lower structure being provided at its lower corner portions respectively with flippers for guiding the spreader and provided at its both sides respectively with clamp means for coupling a container thereon; and an extendable link mechanism connected between the upper structure and the lower structure.

2. A spreader guide apparatus according to Claim 1, wherein the link mechanism comprises a plurality of main link members connected with one another into a scissors shape and a plurality of assistant link members respectively connecting selected ones of the main link members to the upper and lower structures.

3. A spreader guide apparatus according to Claim 1, wherein the length of each of the assistantlink members corresponds to 1/3 to 2/3 of the length of each of the main link members.

1 0 4.

4. A spreader guide apparatus according to Claim 1, wherein the lower structure has a stopper adapted to limit an 5 extension of the link mechanism to a predetermined angle.

5. A spreader guide apparatus according to Claim 1, wherein the link mechanism comprises a plurality of link members connected with one another into a scissors shape between the upper and lower structures, the uppermost ones of the link members respectively having one upper end pivotally mounted to the upper structure and the other upper end slidably disposed in a slide groove formed at the upper structure, and the lowermost ones of the link members respectively having one lower end pivotally mounted to the upper structure and the other lower end slidably disposed in a slide groove formed at the lower structure.

6. A spreader guide apparatus according to Claim 1, wherein the upper structure includes upper supporters fixedly mounted on both ends of the upper structure and provided with insert pins each resiliently supported by a spring, respectively, and the lower structure includes lower supporters fixedly mounted on both ends of the lower structure and adapted to receive the upper supporters, respectively, at 26 a retracted position of the spreader guide apparatus, whereby the spreader guide apparatus is firmly kept at the retracted position.

7. A spreader guide apparatus according to Claim 1, wherein the lower structure has a position sensor 13a attached to a lower surface of the lower structure adjacent to the flippers and adapted to sense a stopped position of the lower structure 13.

8. A spreader guide apparatus according to Claim wherein the position sensor is a photosensor.

9. A spreader guide apparatus according to Claim 1, further comprising a clamp mechanism mounted to a corner hole formed at a lower corner portion of the container.

10. A spreader guide apparatus according to Claim 9, wherein said clamp mechanism comprises a clamper 19 selectively inserted in the corner hole of the container and resiliently supported by a spring, and a hydraulic cylinder adapted to operate the clamp.

11. A spreader guide apparatus according to Claim 1, further comprising turnover means for vertically turning over 1 1 27 1 & the spreader guide apparatus including the upper structure, the link mechanism and the lower structure.

12. A spreader guide apparatus according to Claim 1, wherein the turnover means comprises a driving motor supported on a bracket secured to the spreader, and a turnable connection arm connected at one end thereof to a driving shaft of the driving motor and connected at the other end thereof to the upper structure.

13. A spreader guide apparatus according to Claim 1, wherein the turnover means comprises a connecting rod attached at one end thereof to the upper structure, a driven sprocket provided at the other end of the connecting rod, and a driving sprocket driven by a drive motor, and a chain connecting the driven sprocket with the driving sprocket.

14. A spreader guide apparatus according to Claim 11, wherein the turnover means comprises a connecting rod attached at one end thereof to the upper structure and pivotally mounted on a shaf t f ixedly mounted to a bracket 31 f ixedly mounted to the spreader, a driven gear provided at one end of the shaft, and a driving gear engaged with the driven gear and driven by a drive motor.

a 0 28

15. A spreader guide apparatus according to Claim 11, wherein facing ones of the assistant link members defines therebetween a space determined by the following equations:

i) a + 2Licosei = L2COS@2 ii) h/2 = L2sin82 + Lisinei iii) Lisin@l + Licos@itan@2 > link width + 10 (hain) iv) ei < 90x (hmax) wherein, a represents the space, L2 the length of each of the main link members, h the height of the extended link 10 mechanism, hmin the height of the retracted link mechanism, hmax the height of the fully extended link mechanism, @i the maximum extended angle of each of the assistant link members, and 92 the maximum extended angle of each of the main link members.

is

16. A spreader guide apparatus as claimed in claim 1 including an arrangement substantially as described herein with reference to any one of Figs. 2-16 of the accompanying drawings.