AU619064B2

AU619064B2 - A grapple

Info

Publication number: AU619064B2
Application number: AU46636/89A
Authority: AU
Inventors: Leo Ronald Flanigan
Original assignee: TTS TRANSPORT Pty Ltd
Current assignee: MIM Holdings Ltd
Priority date: 1988-12-14
Filing date: 1989-12-13
Publication date: 1992-01-16
Anticipated expiration: 2009-12-13
Also published as: AU4663689A

Description

TITLE: A GRAPPLE

Technical Field

The present invention relates to a grapple and more particularly, to a grapple intended for use in handling a block of lead, a slab of building material, a bundle of sheets, each sheet having an aperture which defines a cylindrical bore, or any other material in which a precast central bore can be formed, by overhead lifting means.

The invention will herein be described with particular reference to handling lead blocks but it will be understood to be applicable for handling of other materials. Background Art

Hitherto, general handling of lead blocks and other similar bulk materials has been a costly, lengthy, and inefficient process. Conventional methods of handling lead blocks involve the use of a forklift to transport and bundle individual blocks on wharfs and the subsequent utilization of a crane to lift a bundle of 3 blocks by means of chains manually slung under the stack. The chains are remotely released and withdrawn from between the stack. On discharge the chains are once again manually dragged under the corners of the bundle of blocks using long reach steel hooks or the like and the bundle is then lifted by crane and landed on a truck on the wharf. Similar handling difficulties are encountered at other locations.

Alternatively, a strapping method may be employed in which metal straps are manually fabricated, formed and placed onto the individual lead blocks which are subsequently loaded and discharged by a forklift.

Both these methods have proved to be time-consuming, slow, inefficient and costly due to the labour-intensive nature of the operation. Additionally, such methods are hazardous for the operators. For example, the chains may slip from under the bundle of blocks or the metal straps may become damaged and fail. The act of drawing chains under a bundle of blocks and attaching them to crane hooks is particularly hazardous. Disclosure of Invention

An object of the present invention is to provide a grapple which at least in preferred embodiments avoids or ameliorates the disadvantages of the prior art. According to a first aspect the present invention consists in a grapple comprising: a shaft adapted to be lifted; a collar mounted for translation with respect to the shaft; a plurality of fingers, each finger pivotally mounted with respect to the collar for movement between a disengaged configuration in which the finger extends in a shaft axial direction and an engaged configuration in which the finger extends at an angle to the axial direction; and a head mounted to the shaft and adapted to swing the fingers to the engaged configuration when the head is drawn by the shaft towards the collar.

For preference the shaft is adapted to be lifted by a hook eye suitable for engagement by a crane hook or the like.

A first end of each finger is pivotally mounted to tήe collar at a first pivot point for swing movement in a plane intersecting the shaft.

Preferably also the undersurface of each finger is provided with a cam surface which cooperates with a shaped upper surface of the head to swing the finger from a disengaged to an engaged configuration.

Desirably the shaft is raised or lowered with respect to the collar by means of compressed air, but other driving means may be used. In preferred embodiments the apparatus is adapted to lift a slab or block having a central bore with a shoulder peripheral to the bore. The head of the grapple is of a dimension which is comparable with that of the collar and is of an outside diameter slightly less than the inside diameter of the bore in the slab.

According to a second aspect the invention consists in a method for lifting an object provided with a bore and a shoulder peripheral to the bore, said method comprising the steps of inserting a grapple according to the first aspect in a disengaged configuration into the bore until the fingers are at or below the peripheral shoulder and then drawing the head towards the collar to swing the fingers into an engaged configuration.

When drawn towards the collar the head abuts an edge of the fingers causing them to swing outwardly. When the grapple is lifted by a crane the fingers engage the shoulder of the bore, preventing the head from being withdrawn through the aperture and enabling the block to be lifted. Brief Description of Drawings

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings wherein:

Figure 1 shows a partially cut-away cross-sectional elevational view of an embodiment of the lifting device in the disengaged configuration. Figure 2 shows a partially cut-away cross-sectional elevational view of the lifting device of figure 1 in an engaged configuration.

Figure 3 shows a partly cut-away cross sectional elevational view of another embodiment of the lifting device in the disengaged configuration.

Figure 4 shows a partly cut-away cross-sectional elevational view of the lifting device of Figure 3 in an engaged configuration.

Figure 5 is a sectional view taken through line 5-5 of Figure 3. Best Mode for Carrying Out Invention

With reference to the drawings, there is shown a grapple 1 comprising a shaft 2 with integral piston 3 and a head 4 threadably mounted to the shaft and secured by bolt 5. A collar 6 is mounted for translation with respect to shaft 1 and piston 3.

The grapple is provided with a means of attachment to a crane hook for example a hook eye 7 threadably mounted on the shaft end remote from the head 4.

A plurality of fingers 8 are pivotally mounted by means of pins 9 to collar 6 for movement between a disengaged configuration as shown in Figure 1 in which fingers extend in a shaft axial direction and an engaged configuration (Fig. 2) in which the fingers extend outwardly at an angle to the axial direction.

Movement of the fingers 8 between a disengaged configuration and an engaged configuration is effected by means of the head 4 . The head 4 is of generally bulbous shape having a flared upper surface 10 and a tapering lower surface 11. The flared upper surface 10 is adapted to engage the chamfered lower edge 12 of fingers 8 causing them to swing out into a position parallel to the upper surface of the head.

Piston 3 is disposed within an air cylinder 13 which is threadably mounted to collar 6. Piston 3 is driven by means of compressed air admitted to air cylinder 13 by means of air supply connections 14 and 15 located on a top flange 16 of air cylinder 13. Compressed air is admitted to either the top of air cylinder 13 by means of air supply connection 14 via air passageway 17 or the bottom of the air cylinder by means of air supply connection 15 via air passageway 18.

Desirably, when in the disengaged configuration, fingers 8 are held in the shaft axial direction by a guide sleeve 19, slidingly mounted on air cylinder 13 by means of bush 22 integral therewith. Guide sleeve 19 has an upper radial flange 20, a lower tapered edge 21 and serves both to centre the device and prevent the fingers from swinging outwardly in the event of the grapple being displaced from a substantially vertical position. Axial movement of the guide sleeve 19 is limited in the upward direction by the top flange 16 of the air cylinder 13 and in the downward direction by abutment of the lower edge of bush 22 with upper edge 23 of collar 6.

Preferably, top flange 16 of air cylinder 13 is provided with an annular spoked frame 40 fixedly mounted to top flange 16. Radially extending spokes 41 serve as handles and are provided for the assistance of stevedores in centering the grapple in the precast bore.

In Figures 1 and 2 the grapple is shown inserted into a precast central bore 24 defined by a cylindrical bore wall 25 of a 5 tonne lead block 26 of which only a scrap is illustrated. Bore wall 25 has a diameter of 125 mm at the upper surface of the block and extends downwardly for 120 mm. Thereafter the bore flares outwardly and downwardly forming a peripheral shoulder 27 which is f ustoconical in shape. In the present example the wall defining shoulder 27 extends at an angle of 45° to the bore axis and at a depth of 360 mm from the upper surface of the block. Peripheral shoulder 27 merges into a cylindrical bore (not illustrated) of greater diameter than bore 24 which extends to the lower surface of block (not illustrated) .

In the engaged configuration, the fingers 8 of the grapple 1 are in abutment with the peripheral shoulder 27, thereby preventing the head 4 from being withdrawn through the bore.

In use, the grapple 1 is suspended by a crane hook passing through hook eye 7 and is presented in a disengaged configuration to a lead block 26. Compressed air is first applied via air supply connection 14 and air passageway 17 so that cylinder 13 moves with respect to piston 3 and collar 6. Fingers 8 are drawn away from head 4 and are then hanging in a shaft axial direction. Guide sleeve 19 drops under gravity until bush 22 abuts the upper edge 23 of the collar 6 retaining fingers 8 coaxial with shaft 2.

Grapple 1 is lowered into precast bore 24 in the disengaged configuration. Tapered edge 21 of guide sleeve 19 serves to centre grapple 1 in the precast bore 24. A top flange 20 of guide 19 engages the upper surface of block 26 and the body of the air cylinder 13 continues to slide with respect to bush 22. In this way the grapple 1 is centralized in bore 24 and the free ends of the fingers 8 move clear below the bottom edge of guide 19. Lowering ceases when top flange 16 of air cylinder 13 engages the upper surface of flange 20 of guide 19 which is supplied on block 26. In this fully inserted, disengaged configuration fingers 8 are parallel to shaft 2 and at or below the peripheral shoulder 27 of bore 24.

The grapple is activated to the engaged configuration by applying compressed air via air supply connection 15 and air passageway 18. Shaft 2 with integral piston 3 are axially displaced relative to cylinder 13, driving head 4 upwardly causing the upper surface 10 of head 4 to engage fingers 8 at cam surfaces 12 so that fingers 8 swing radially into a position parallel to the upper face 10 of the head 4. In this position the upper face of each finger 8 is parallel to peripheral shoulder 27 of precast bore 24 in the block 26.

As grapple 1 is raised in the engaged configuration, the body of the air cylinder 13 slides through the guide 19 until the fingers 8 engage shoulder 27 of the precast bore, the fingers 8 acting as a wedge or chock and preventing head 4 from being withdrawn from the block. In the raised position grapple 1 cannot be activated to release the load as the forces available to move the shaft head down relative to the air cylinder are far less than the forces present holding the shaft head to the fingers when supporting the load.

As the block is lowered onto a supporting surface, the load is transferred from the grapple. The body of the air cylinder 13 slides down guide 19, and the undersurface of top flange 16 of air cylinder 13 engages the upper surface of flange 20 of guide 19 which engages the upper surface of the block 25. Simultaneously the fingers disengage the shoulder 27 of the precast hole. At this stage the grapple may be returned to a disengaged configuration by the application of compressed air via air supply connection 14 and air passageway 17. Air cylinder 13 moves in a downward direction relative to shaft 2 and integral piston 3. Head 4 is thrust downwards and the fingers fall parallel to the axis of the shaft.

As the grapple is withdrawn from bore 24 air cylinder 13 moves upwards through the guide bush 22. The fingers 8 are once again held in the shaft axial direction by the guide 19 and the grapple is lifted clear of the hole with the fingers retained in the disengaged configuration.

Apparatus according to the invention can take many forms.

For example, air cylinder 13 could be replaced by an inner and outer cylinder defining air passageway between them.

In another embodiment, the means of attachment 7 could comprise a lifting frame attachment to a crane or crane hook or alternatively any other means which would enable the device to be lifted. Furthermore, the number of fingers 8 mounted on the collar 6 is variable.

In yet another embodiment, shaft 2 could be driven relative to cylinder 13 by hydraulic means or without a piston for example by an electrical motor driving a screw threaded arrangement.

As shown more particularly in Figures 3 and 4, fingers 8 may be pivotally mounted by means of linkages 28 to collar 6 for movement between a disengaged configuration as shown in (Figure 3) in which the linkages extend in a shaft axial direction and an engaged configuration (Figure 4) in which the linkages extend outwardly at an angle to the axial direction. One end of linkage 28 is pivotally mounted to collar 6 by means of pins 29. Linkage end remote from collar 6 is pivotally mounted to finger 8 by means of pin 30. In this embodiment the upper surface 31 of finger 8 is serrated for improved gripping of the internal bore wall.

The grapple of this embodiment is particulary useful for lifting a bundle of sheets generally indicated at 32, each sheet 33 having an aperture which defines a central bore 34 through the bundle. In a perferred embodiment, the grapple is inserted into the central bore in a disengaged configuration until at least a portion of the fingers are at or below the aperture of the first sheet. The head is then drawn towards the collar to swing a finger 8 into an engaged configuration in which it grips the sheets in the bundle. Desirably the upper surfaces of the fingers are serrated for improved gripping of the internal bore wall.

Different arrangements of bore 24 may be used. For example, the shoulder 27 could be horizontal and could be the lower surface of a slab provided with a cylindrical bore.

A grapple according to this invention may be utilized for lifting any other materials which have appropriate attachment receptacles therein or attached thereto, for example building materials.

As will be apparent to those skilled in the art, the shape and dimensions of the device herein described may be altered without departing from the scope of the invention herein disclosed.

Claims

CLAIMS : -

1. A grapple comprising : a shaft adapted to be lifted; a collar mounted for translation with respect to the shaft; a plurality of fingers, each finger pivotally mounted with respect to the collar for movement between a disengaged configuration in which the finger extends in a shaft axial direction and an engaged configuration in which the finger extends at an angle to the axial direction; and a head mounted to the shaft and adapted to swing the fingers to the engaged configuration when the head is drawn by the shaft towards the collar.

2. A grapple according to claim 1 wherein a finger is pivotally mounted to the collar at a first pivot for swing movement in a plane intersecting the shaft.

3. A grapple according to claim 1 wherein each finger is mounted to the collar by a linkage means comprising an axially extending linkage member pivotally mounted at a first pivot to one end of the collar and at a second pivot spaced from said first pivot to a finger for movement between a disengaged configuration in which the linkage members extend in a shaft axial direction and an engaged configuration in which the linkage members extend outwardly at an angle to the axial direction.

4. A grapple according to any one of the preceding claims wherein the undersurface of each finger is provided with a cam surface which cooperates with a shaped upper surface of the head to swing the finger from a disengaged to an engaged configuration.

5. A grapple according to any one the preceding claims wherein the upper surface of at least one of the fingers is provided with gripping means for gripping of the internal bore wall of the object to be lifted.

6. A grapple according to claim 5 wherein the upper surface of at least one of the fingers is serrated for improved gripping of the internal bore wall.

7. A grapple according to any one of the preceding claims wherein the shaft is raised or lowered with respect to the collar by means of compressed air.

8. A grapple according to any one of the preceding claims further comprising a means of attachment for a crane hook mounted on the shaft end remote from the head.

9. A grapple according to claim 8, wherein the means of attachment is a hook eye threadably mounted on the shaft end remote from the head.

10. A grapple according to any one of the preceding claims further comprising a guide sleeve coaxially mounted for sliding movement with respect to the shaft for limiting the outward excursion of the fingers when said fingers are in the disengaged configuration.

11. A grapple according to any one of the preceding claims wherein the head is of generally bulbous shape having a flared upper surface for engagement with the cam surface of each finger- and a tapered lower surface.

12. A grapple according to any one of the preceding claims further provided with handle means whereby to assist in the centering of the grapple in a central bore in an object to be lifted.

13. A method for lifting an object provided with a bore and a shoulder peripheral to the bore, said method comprising the steps of inserting a grapple according to any one of the preceding claims in a disengaged configuration into the bore until the fingers are at or below the peripheral shoulder and then drawing the head towards the collar to swing the fingers into an engaged configuration.

14. A method according to claim 13, wherein the peripheral shoulder is the lower surface of the object to be lifted.

15. A method according to claim 14 wherin the lower surface is substantially horizontal.

16. A method according to claim 15 wherein the object to be lifted is a pile of sheets.

17. A method for lifting a bundle of sheets, each sheet having an aperture which defines a central bore through the bundle, said method comprising the steps of inserting a grapple according to any one of the claims 1-12 in a disengaged configuration into the bore until the fingers are below the aperture of the uppermost sheet and then drawing the head towards the collar to swing the fingers into an engaged configuration in which a finger grips the sheets in the bundle.

18. A grapple substantially as herein described and with reference to the accompanying drawings.

19. A method according to any one of claims 13-17 substantially as herein described.