GB2351065A - Container grappler - Google Patents

Abstract

A grappler for lifting a cargo container has a spreader frame 10 supporting two pairs of opposed arms 14 each extending downwardly from the frame, the lower end 19 of each arm 14 being arranged for inter-engagement with a respective lifting recess provided on the container. Each arm has at its lower end 19 a claw 25 mounted for rotational movement between a first position (Figure 2A) where the claw 25 lies wholly within the confines of the arm, and a second position (Figure 2B) where the claw 25 projects out of the arm towards the opposed arm of its pair, for engagement with an adjacent lifting recess on the container. An hydraulic ram 26 is incorporated within the arm 14 to effect rotational movement of the claw 25, between its two positions. Preferably, the claw is moved via a rack 29 and pinion 32.

Description

ReM 1751 sp -1-1 - 2351065 CONTAINER GRAPPLER This invention relates to a

container grappler - that is to say, a grab device configured to engage with and lift a cargo container.

So-called swap-bodied cargo containers are being used on an increasing scale for the carriage of goods of various kinds. Swap-bodied containers have a platform with rigid end panels and soft side panels (as defined in EN452), somewhat similar to a curtain-sided vehicle body. Such containers have several advantages as compared to conventional rigidbodied ISO cargo containers, usually of steel, but have the disadvantage that the containers cannot be stacked, unlike conventional containers, in view of the reduced strength of the structure. In addition, a grappler for the handling of a swap-bodied container normally must engage with a lower part of the container and not with the top of the container. In turn, this means that the containers must be loaded for example in the hold of a ship or on the deck with significant gaps between the containers, to permit access for grappler arms to pass between the containers and engage with the lower region of a container to be lifted.

A typical grappler has a spreader frame with a width slightly less than the width of the container, and having two pairs of opposed arms depending downwardly from the frame, at or adjacent the two ends thereof. Each arm has at its lower end a hook-like bottom fiffing in the form of a claw projecting towards the opposed arm, and which claw may engage in a lifting area defined in the swap-bodied container floor region, which area usually takes the form of a recess configured to receive the claw. Each arm is pivoted to the spreader frame, and is movable towards the opposed arM to engage the Refl 1751 sp claws with the lifting recesses on opposite sides of the container, so as thereafter to permit lifting of the container by a hoist or crane coupled to the spreader frame. Conversely, once a container has been deposited, the claws may be disengaged from the lifting recesses by pivoting each arm away from 5 its opposed arm.

It will be appreciated that in order to allow the grappler arms to pass between adjacent containers loaded for example in a ship's hold, the containers must be spaced by more than the thickness of an arm and its projecting claw, so that the arms may move vertically between two adjacent containers. In fact, the spacing of the containers must be significantly more than the minimum required, in view of the pivoting action of the arms and to allow easy operation without accidental fouling through slight misalignment of the spreader frame with the container.

A claw may project laterally from a grappler arm by typically 50mm or so. Thus, the total dead space between containers loaded into a ship's hold can be significant and if the hold had been designed to accommodate conventional rigid ISO containers to be lifted from the top, at least one entire row of containers may have to be omitted from the loaded hold.

It is a principal object of the present invention to provide a grappler for lifting a cargo container, and in particular, though not exclusively, a swapbodied container, which permits the space between adjacent containers to be lifted by the grappler to be minimised.

According to this invention, there is provided a grappler for lifting a cargo container, comprising a spreader frame supporting at least one pair of opposed downwardly depending arms the lower ends of which are arranged Refl 1751 sp for inter-engagement with respective lifting recess of a container to be lifted, each arm having at or adjacent its lower end a respective claw movable between a first position where the claw lies substantially wholly within the confines of the arm and a second position where the claw projects laterally beyond the arm towards the opposed arm for engagement with an adjacent lifting recess of the container, and power drive means adapted to effect movement of the claw between its said two positions.

With the grappler of this invention, the effective thickness of each arm is minimised by arranging for the claw to be movable between retracted and extended positions. In this way, the spacing required between containers to be lifted by the grappler may be minimised. There is the additional advantage that as the claw is retracted when the grappler is being moved to or from a container-engaging position, the likelihood of an arm fouling on a part of the container in the course of that movement is much reduced. Moreover, in the event that a container might itself move slightly when being transported, there is a greater chance that the grappler might still be engaged with the container on account of the minimal thickness of each arm and the lack of an obstructing claw projecting from that arm.

Though the grappler of this invention is primarily intended for use with swap-bodied containers, and so each arm should have a sufficient length to extend to the bottom of the container when the spreader frame overlies the top of the container, the grappler may be used with other kinds of container. For example, it may be used with a conventional rigid ISO container, the arms again having a sufficient length to reach the bottom of the container when the spreader frame overlies the top of the container. In the alternative, the Refl 1751 sp grappler may have shorter arms and be intended to engage lifting areas of the container part-way up the side of the container or even at the top of the container.

Most preferably, each claw is pivoted to its associated arm, whereby the claw may pivot between its two said positions. In this case, each claw advantageously pivots downwardly on moving from its first (retracted) position to its second (extended) position, and conversely pivots upwardly on moving from its second position to its first position. An abutment may be provided on the arm, which abutment is engaged by a part of the claw when in its second position, so as to restrain further downward pivoting movement thereof. Preferably, each claw is arranged as a first order lever having a portion projecting on the opposite side of the pivot to the main part of the claw, and said abutment is disposed above the pivot for engagement by the projecting portion when the claw is in its second position.

Various mechanisms may be provided for moving each claw between its retracted and extended positions, but preferably each arm is provided with a respective hydraulic ram arranged to effect movement of that arm's claw. For example, each arm may be hollow with the ram mounted therewithin above the claw and coupled to the claw by means of a toothed rack engaged with a pinion connected to the claw.

As with the known designs of grappler, the two arms may be pivoted to the spreader frame so that the lower ends of the two arms may be moved towards and away from each other. A single spreader frame preferably has two spaced-apart pairs of opposed arms, each furnished with a movable claw at or adjacent its lower end, whereby a container may be lifted by engaging Refl 1751 sp -5 the claws of the four arms of the single spreader frame with the container lifting recesses, the frame in turn being coupled to a crane.

Preferably, each claw is provided with a lifting surface adapted to engage a downwardly-facing surface of a lifting recess of a container, with a groove formed behind the lifting surface of the claw and in which may be received a lip formed along the outer edge of the lifting recess. In this way, once a claw has been fully engaged in a lifting recess and carries part of the weight of the container, the location of the lip in the groove will serve to prevent inadvertent release of the claw from the recess. So as to increase safety in operation, it is preferred for the arms to be provided with respective proximity detectors, the outputs of which are used to control the movement of the respective claws between their two positions. Moreover, further detectors may be provided in each claw to determine the location of the lifting recess lip in the groove of the claw, the output of which sensors is used to prevent lifting movement of the grappler until proper engagement has been determined, or proper relase when a container is to be set down.

This invention extends to the combination of a grappler of this invention as described above, in combination with a crane from which the grappler is suspended for the loading and unloading of swap-bodied containers on to or from a vehicle or a ship.

By way of example only one specific embodiment of grappler constructed and arranged in accordance with the present invention will now be described in detail, reference being made to the accompanying drawings, in which:

Figure 1 is an isometric view of the complete grappler; ReM 1751 sp Figures 2A and 2B are detail views of a grappler arm and its mounting to the spreader frame of the grappler, respectively with the claw retracted and extended; Figure 3 is a detail view on the lower end of one grappler arm, with a 5 corner plate removed for clarity; Figure 4 is an isometric view on an enlarged scale of a grappler claw as used at the lower end of an arm; Figure 5 is a cross-section through the lower end of an arm; and Figure 6 is a view on the lower end of the arm with a channel flange removed for clarity.

Referring initially to Figure 1, there is shown an embodiment of a complete grappler assembly of this invention, intended for use with a swapbodied container constructed in accordance with European Standard EN452. Such a container has a frame provided with rigid end panels, which may be removable, and side panels made of a flexible material whereby access to the interior of the container may be gained by withdrawing the flexible side panels. The container has lifting areas definedby recesses in the side edges of the floor of the container, for engagement by a suitably configured grappler having downwardly depending arms with hook portions adapted to be received in the lifting recesses.

The grappler comprises a generally rectangular spreader frame 10 having longitudinal rails 11 between which are mounted housings 12 containing control gear, hydraulic pumps and so on, for the operation of the grappler. At each end of the spreader frame, there is a respective subframe assembly 13, each of which supports a respective pair of downwardly Refl 1751 sp depending opposed grappler arms 14. Each arm 14 is pivoted to the respective sub-frame 13 about an axis 15 parallel to the length of the rails 11, the angular position of the arm with respect to the sub-frame being controlled by a ram 16 (Figures 2A and 213) connected between the arm and a pair of trunnion plates 17 secured to a cross-member 18 of the sub-frame. In this way, operation of the rams 16 associated with a pair of arms 14 allows the lower ends 19 of those arms to be moved towards and away from each other. Each sub-frame 13 is provided with brackets 20 (usually called twist-lock corners, as used on ISO containers) by means of which the grappler may be suspended from a crane or other hoist device suitable for the lifting and handling of containers.

The mechanism a thte lower end of each arm 14 is normally covered by a plate 21.

Figure 3 shows in greater detail the arrangement at the lower end 19 of an arm 14, with the cover plate 21 removed. The lower end of the arm is of channel-shaped cross-section and pivoted between the flanges 24 of that channel is a claw 25, shown in Figure 4. The claw may be moved between an extended position shown in Figures 2B and 3, where the claw projects from the inwardly directed face of the arm 14 towards the opposed arm and a retracted position (Figure 2A) where the claw 25 lies wholly within the confines of the flanges of the channel. Such pivoting movement of the claw is effected by an hydraulic ram 26, the cylinder of which is secured to the web 27 of the channel, and the piston rod 28 of which is secured to a linear toothed rack 29 slidably supported against the web 27 of the channel. A cross-member 30 extends between the flanges 24 of the channel and serves Refl 1751 sp cross-member 30 extends between the flanges 24 of the channel and serves to guide movement of the toothed rack 29, along the length of the arm. The rack also extends through and is guided by a groove 31 formed in the claw 25. A toothed pinion 32 is mounted in that groove and is secured to the claw, the pinion teeth meshing with those on the rack 29 whereby linear movement of the rack on operation of the ram 26 causes the claw to turn about its pivotal connection to the flanges 24.

The claw 25 has a main body 33 defining a bore 34 through which extends a pin 35 pivotally mounting the claw to the arm 14. A bar 36 is mounted on the forward portion 37 of the claw which projects beyond the arm when in its extended position, the bar being parallel to the bore 34. That bar 36 provides an upwardly facing lifting surface 38 which may engage a downward ly-facing part of a lifting recess 39 (Figure 5) of a container. A groove 40 extends between the bar 36 and bore 34, a lip 41 along the outer edge of the lifting recess 39 of the container being receivable in that groove 40 so as to give a secure inter-engagement between the claw and the lifting recess when a container is to be lifted. As shown in the drawings, a resilient pad 42 is provided between the main body 33 of the claw and bar 36, to allow for minor variations in the planes of the lifting surface 38 of the bar and the corresponding surface of the lifting recess.

To the other side of the body 33 beyond bore 34 there is an upwardly facing abutment surface 43 which engages a corresponding surface formed on the cross-member 30, when the claw is in its extended position. This serves to limit downward pivoting movement of the claw and provides the Refl 1751 sp reaction for the weight of a container being picked up by the lifting surface 38 of the claw.

A detector is provided to determine proper engagement of the claw 25 with a lifting recess, with the lip 41 located in the groove31. A rocker 44 (Figure 6) is carried on pin 35, positioned in a rebate 45 at one end of the claw as best seen in Figure 4. The rocker has a cam surface engaged by one end of a push-rod 46 carried in a bore in the cross-member 30, the other end of the push rod operating a switch 47. The front edge of the rocker has a surface 48 normally projecting in the groove but which will be depressed by the lip 41 as the claw 25 properly engages a lifting recess; in turn this will operate the switch 47.

A proximity detector 49 is mounted on the cross-member 30 to face the opposed arm to detect the closeness of the arm to a container. Yet another detector (not shown) may be provided to detect whether the claw is in its extended or retracted positions. Only when the four arms 14 have been detected as being sufficiently close to a container and the lip of a lifting recess has positively been detected in each of the four grooves is a signal given permitting the raising of the grappler, as a whole. Conversely, when the grappler is to be lifted away from a released container, that is permitted only when all four arms 14 have been detected as being moved away from the container by a sufficienflextent and the claws 25 have been detected as being in their withdrawn (Figure 2A) positions.

By using the grappler as described above, it is possible to arrange swapbodied containers for example in a ship's hold with a relatively small spacing between adjacent containers, having regard to the arrangement of Re(1 1751 sp the lifting claw at the lower end of each of the four arms of the grappler. The grappler may also be used in conjunction with a racking system for swap-bodied containers, for example in a ship's hold or in a shipping yard or dock-side, enabling a relatively small spacing to be achieved between adjacent racks and minimising the rack width containing the swap- bodied containers. Further, though described above primarily with reference to swap-bodied containers, the grappler may of course be used with conventional ISO rigid-bodied containers.

Refl 1751 sp,

Claims (16)

1 A grappler for lifting a cargo container, comprising a spreader frame supporting at least one pair of opposed downwardly depending arms the lower ends of which are arranged for inter-engagement with respective lifting recesses of a container to be lifted, each arm having at or adjacent its lower end a respective claw movable between a first position where the claw lies substantially wholly within the confines of the arm and a second position where the claw projects laterally beyond the arm towards the opposed arm for engagement with an adjacent lifting recess of the container, and power drive means adapted to effect movement of the claw between its said two positions.

2. A grappler as claimed in claim 1, wherein each claw is pivoted to its associated arm whereby the claw performs a pivoting movement between its two positions.

3. A grappler as claimed in claim 2, wherein each claw pivots downwardly on moving from its first position to its second position.

4. A grappler as claimed in claim 3, wherein each claw when in its second position engages a respective abutment on the arm which restrains further downward pivoting movement thereof.

5. A grappler as claimed in claim 4, wherein each claw is arranged as a first order lever having a portion projecting on the opposite side of the pivot to the claw, and said abutment is disposed above the pivot for engagement by said portion when the claw is in its second position.

ReM1751sp

6. A grappler as claimed in any of the preceding claims, wherein each arm is provided with a respective hydraulic ram arranged to effect movement of the associated claw between its two said positions.

7. A grappler as claimed in any of claims 2 to 5 and in claim 6, wherein 5 the ram is mounted within the arm above the claw and is coupled to the claw to effect movement thereof.

8. A grappler as claimed in claim 7, wherein each arm is provided with a linear toothed rack mounted for movement along the length of the arm under the action of the ram, which rack is engaged with a pinion connected to the claw to effect pivoting movement thereof.

9. A grappler as claimed in any of the preceding claims, wherein the two arms are pivoted to the frame for movement of the lower ends of the arms towards and away from each other.

10. A grappler as claimed in any of the preceding claims, wherein the 15 frame is provided with two pairs of opposed arms each furnished with a claw at or adjacent its lower end.

11. A grappler as claimed in any of the preceding claims, wherein each arm is provided with a proximity detector the output of which is used to control the movement of the respective claw to its second position,

12. A grappler as claimed in any of the preceding claims wherein the claws are configured for engagement with the lifting recesses of a swap- bodied container.

13. A grappler as claimed in claim 12, wherein each claw is provided with a lifting surface, a groove being formed behind that surface, and a lip formed along the outer edge of the claw-receiving recess of a container being Refl 1751 sp, locatable in that groove when the claw has properly been engaged with a lifting recess of a container.

14. A grappler as claimed in claim 13, wherein a sensor is provided on each arm to determine the location of the lifting recess lip in the groove of a claw engaged in that recess, lifting movement of the grappler being controlled by the output of the sensor.

15. A grappler as claimed in claim 1 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

16. The combination of a grappler as claimed in any of the preceding claims and a crane from which the grappler is suspended, for the loading or unloading of swap-bodied containers on to or from a vehicle, ship or racking system.