This invention relates to a bundle strap installation apparatus and has particular though not exclusive application as a facility for strapping the individual bundles of a unit of bundles being transported according to USLM (Unit Strap Lifting Method) practice.

USLM has become a standard technique for handling and transporting metallurgical products such as metal ingots and electrode plates. These products are handled in units of similar bundles which must then each be strapped for transport. The standard practice is to apply to each bundle a so called M-strap which provides peaks readily hooked by a lifting spreader frame. Despite the

efficiency and minimal labour input achieved with the USLM technique as a whole, the step of applying the M-straps to the bundles is time consuming and cumbersome. Typically a unit of bundles is brought to a strapping station where each bundle is individually separated by a fork-lift. While the fork-lift, driven by one worker, holds the separated bundle, a second worker manually applies the straps. Apart from the inefficiencies of this approach, it is thought by some to be not entirely safe.

The general objective of the invention is therefore to improve the manner in which straps are applied to the individual bundles of a unit of bundles for handling and transport according to USLM practice, although the invention does of course have wider application.

The invention accordingly provides bundle strap installation apparatus, comprising: a plurality of trolleys movable apart from a compact condition for receiving a unit of bundles to a spread condition in which the bundles of the unit are spread apart to form sub-units to allow respective straps to be placed on the bundles; means to move the trolleys from said compact condition to the spread condition; and means to temporarily lift the bundles off the trolleys to facilitate positioning of straps about the bundles.

Advantageously, said moving means may be further arranged for returning the trolleys from said spread condition to said compact condition. Return may alternately be effected by separate moving means. In either case, means is preferably provided for ensuring that the strapped bundles revert to a close-packed unit. It may be desirable for the latter means to be retractable below the plane of the trolley tops to facilitate

transport of the unit to and from the trolleys.

There are preferably several trolleys arranged in line. The trolleys most preferably have flanged wheels for rolling movement on a pair of rails. The trolleys are advantageously coupled by chains or other flexible links which define the separation of the trolleys in the spread condition. With this arrangement, the moving means may drive only one of the end trolleys.

The means to temporarily lift the bundles may include respective elongate lifting brackets which simultaneously engage the outside edges of the bundles at opposite sides of the bundles. These brackets are associated with lift means such as plural spaced fluid-powered actuators to lift the brackets. Provision is preferably made to apply a lateral engagement of the brackets against the bundles as well as a vertical lift component with a view to firmly holding the bundles, and to stabilising the bundles against any tendency to topple outwardly.

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which:

FIGURE 1 is a perspective view of an inground bundle strap installation apparatus according to the invention, especially adapted for handling aluminium ingot stacks unitised according to USLM practice;

FIGURE 2 is a longitudinal cross-section on the line 2-2 in Figure 1;

FIGURE 3 is a transverse cross-section on the line 3-3 in Figure 2;

FIGURES 4 and 5 are respectively an enlarged perspective view and a sectional detail, showing the mechanism by which the bundles are lifted off the trolley tops;

FIGURE 6 is an off-centre longitudinal cross-section of the locomotive trolley, showing the linkage for the bulldozer arms; and

FIGURE 7 is a view similar to Figure 3 but showing the bundles elevated.

The illustrated bundle strap installation apparatus 10 is installed in a generally elongate pit 11 surrounded by a level concrete apron 12. The apparatus includes a frame 13 of steel girders, and six trolleys 14 which are movable in a line on rails 15 between a compact condition (Figures 1 and 2) and a spread condition in which the trolleys are spaced apart longitudinally along the pit 11. This motion is effective to separate into spaced sub-units 6, the bundles 7 of a USLM unit of aluminium ingot bundles deposited on the trolleys prior to their separation. The trolleys are dimensioned to accept a 6X2X2 unit of bundles, so that each trolley uniquely receives one 1X2X2 sub-unit; that is, each trolley is 1 bundle long and 2 bundles wide. A hydraulic actuator 16 (Figure 2) is provided under the trolleys for moving the trolleys between the compact and spread conditions. Further sets of four hydraulic actuators 18 (Figure 4) are disposed one set along each side of the pit. These latter actuators 18 form a drive component of a mechanism for temporarily lifting bundles on the spread apart trolleys to thereby facilitate the positioning of straps 8 about the bundles.

Frame 13 is made up largely of I-section steel girders to form a rectangular sub-frame 20 on the floor of the pit, an intermediate rectangular sub-frame 22 and an upper rectangular sub-frame 24 substantially at ground level. Sub-frames 20, 22 are joined by spaced upstanding legs 21 directly welded to the two sub-frames, while sub-frame 24 lies outside sub-frame 22 when viewed in plan

and is supported by multiple outstanding brackets 23 welded to the outside of the longitudinal side rails 25 of sub-frame 22. The running rails 15 are lengths of conventional railway track and are fastened atop the side rails 25 of sub-frame 22. Upper sub-frame 24 is bridged to the surrounding apron 12, over the space occupied by hydraulic actuators 18, by a heavy duty load bearing metal grille 26.

Of the six trolleys 14, five trolleys 14a are identical but the sixth trolley 14b is substantially longer than the others in order to act as a locomotive when returning the trolleys to their compact condition. This will be better explained hereinafter. Each trolley 14a comprises a frame of L-section steel beams 28 under a flat top plate 30 fastened to the frame. The top surfaces 31 of plates 30 are substantially flush with grille 26 and apron 12, and carry multiple nylon wear pads 32 aligned longitudinally of the pit. Each trolley 14a has depending pairs of bearings 34 for two live axles 36 with flanged wheels 38 in engagement with running rails 15.

Trolley 14b is similar at one end to trolleys 14a but the frame 28b and top plate.30b are extended and carry retractable pushing arms 40. It is also to be noted that, despite its greater length, trolley 14b also has just two axle/wheel sets 36b, 38b.

The trolleys are coupled by flexible links in the form of chains 42 which determine the maximum separation of the trolleys in the spread condition.

Trolley driving actuator 16 (Figure 2) necessarily has a very long throw. Its piston 17a is rotatably pinned to a depending plate 44 about midway along trolley 14b, while the cylinder 17b is similarly secured to a cross-beam 46 of intermediate sub-frame 22. This cross-beam 46 is approximately under the third trolley

when the trolleys 14 are in their compact condition. The trolleys are moved from their compact to their spread condition by simply extending the piston 17a, the limit position being determined by the tightening of chains 42.

To recollect the separated sub-units of bundles on the trolleys 14 and reform the USLM unit, it is not sufficient to simply retract the piston 17a and thereby have trolley 14b act as a locomotive to gradually push the remaining trolleys 14 together. A pushing or bulldozer action is also applied to the bundles on the trolleys 14 by means of retractable upstanding arms 40, already mentioned. Arms 40 are large box section beams which are pivoted about point 41 at their front ends. Arms 40 can retract through slots 48 in the top plate 30b of trolley 14b into underlying housings 50 (Figure 6) defined by depending side plates 52, and mesh floor and end walls 54. Arms 40 are raised and retracted by respective double acting hydraulic actuators 56 which lie under housings 50 but still between side plates 52. The cylinders of these actuators are pivoted at 51a to the side plates 52 at the outer end of the trolley while the pistons 55 are pinned at 51b to respective fork structures 53 formed by depending angled side plates 53a on the arms 40. The arrangment is such that retraction of the pistons 55 is effective to rotate the arms 40 upwardly to the pushing position shown in full lines in Figure 6. When retracted by extending pistons 55 (broken lines in Figure 6), the top surfaces of arms 40 are substantially flush with the top surface 31b of trolley plate 30b.

The bulldozer action of arms 40 is facilitated by an upstanding end-frame 58 of I-section girders, suitable diagonals, braces and outer cladding. End-frame 58 provides a rigid backstop to the ingot bundle sub-unit on the end trolley 14a.

The individual aluminium ingots of bundles 7 have overhangs 7a (Figure 3) at each end. The plates 30 and the ingot bundles 7 are so related that each plate is about 1 bundle long and 2 bundles wide, and that the outer overhangs 7a of the bottom layer of ingots just project over the sides of the plate 30. Because these overhangs 7a are off the surfaces 31 of plates 30, an operator may loosely place an M-strap 8 at the outer sides of each bundle by passing it under the overhangs 7a of the bottom layer of ingots and over the overhangs of the top layer. However, the desired position for the strap 8 is at the middle of the bundle. To position the straps in this position the bundles must be spread apart to thereby allow the operator arm access between each bundle, and then the bundles need to be temporarily slightly lifted off the plates 30. The latter operation is the role of hydraulic actuators 18 (Figure 4). There are four actuators 18 at each side of the device which are associated with a single longitudinally extending lifting bracket 60. Lifting bracket 60 normally rests in a retracted position below the level of the upper sub-frame 24 on shoulders 62 of upstanding C-section steel pillars 64.

Pillars 64 are secured by way of triangular gussets 65 to the side rails of sub-frames 20, 22. The pillars 64 lie in facing pairs at each actuator 18 and thereby define upright guideways for respective elongate carriages 66. Each carriage 66 has a pair of connected side plates 67 and spaced live axles 68a for wheels 68 which run inside the pillars 64. Each carriage 66 further has a clevis 70 by which it is pivotally attached to the piston 18a of a respective actuator 18. The cylinder 18b of the actuator is hingedly fastened at 69 to the floor of pit 11. The upper ends of carriages 66 are welded to the outer face of lifting bracket 60 and this bracket itself has an inwardly

projecting lip 72 along its inside face about a third of the way down from its top edge.

The outer side flanges of pillars 64 are fitted at their upper ends with inside cam surfaces 74 (Figure 5) which guide wheels 68 and therefore carriages 66 and lifting bracket 60 inwardly as the lip 72 engages the overhangs 7a of the ingots. This camming action moves the inside surface of lifting bracket 60 above lip 72 into engagement with the outer ends of the overhangs as the continued action of actuators 18 drives carriage 66 upwards and lifts the ingots off the trolley plates 30. (Figure .7) The inward movement of lifting brackets 60 has two purposes. Firstly, it allows a reasonable tolerance in the exact positions of the ingot bundles and secondly, in the fully raised position, provides an inward clamping action on the bundles. This inward clamping action presses the two pairs of bundles together and ensures that they lift off the trolleys 14 at the centre, albeit with a slight bow. The clamping action also provides a firm lateral force on the bundles to stabilise them against outward toppling.

The fully elevated position of the lifting brackets 60 and bundles is shown in Figure 7. It will be seen that the M-straps 8, which had earlier been placed under the ingot overhangs 7a but on the inside of the lifting brackets 60, may now be easily manipulated about the bundles to a central position 8*. When this is complete, hydraulic actuators 18, which are double acting, are gently activated to return the separated bundles to the trolleys 14. Actuators 56 are retracted to raise the pushing arms 40 and finally actuator 16 is retracted to drive the trolleys 14 together against backing frame 58.

The sequence of operation of the apparatus will again now be reviewed. With lifting arms 40 retracted, a

straddle carrier is employed to bring a 6 X 2 X 2 unit 6 of ingot bundles 7 onto the panel defined by trolley plates 30 from the end opposite backing frame 58. The ingots are deposited so that a 1 X 2 X 2 stack of four bundles is respectively placed on each trolley plate 30. The straddle carrier is then driven away and actuator 16 extended to push the trolleys along rails 15 to their maximum spread condition defined by the tautening of chains 42. The operators then place M-straps 8 on each of the twelve bundles at each side of the installation by manually fitting the straps about the ingot overhangs 7a. Actuators 18 are extended to lift brackets 60 into engagement with the overhangs 7a and then, while cams 74 ensure that the bundles are pushed together from the outside, the six 2 X 2 stacks or sub-units are lifted off the trolleys 14. The operators return and manipulate each of the straps 8 to the centre of its bundle. The ingot bundles are then lowered onto the trolleys, the arms 40 are raised and the trolleys 14 and bundles pushed together as already described. The unit 6 is thereby reformed with M-straps 8 in place and is recovered from the installation by a straddle carrier.

A desirable safety feature is that none of the actuators 16, 18, 56 can be activated unless each operator authorised to be within the vicinity is grasping a separate single deadman's handle specifically for that operator.