AU2007200211B1 - A Quick Release Lifting Hook - Google Patents

Description

O A Quick Release Lifting Hook 'n Field of the Invention.

00 This invention is directed to a lifting hook which can lift various members such as roof trusses, beams, girders, and other types of relatively heavy members and where the hook can be released from the material in an elevated position. The invention is i particularly directed to a specially designed lifting hook which can be released from the material in an elevated position but in such a manner that this can be completed by C 10 a person standing on the ground. The invention will be described with reference to lifting roof trusses but it should be appreciated that no particular limitation should be placed on the use of the lifting hook merely by describing this particular embodiment of the invention.

Background Art.

Roof trusses are typically lifted into position by a crane. The crane will lift the roof trusses onto the top of the wall. The trusses then need to be positioned in a spaced apart relationship on top of the wall with a typical spacing between the trusses being between 1-3 m.

Normally, a person will stand on top of the wall and will manoeuvre each roof truss into the correct position while the roof truss is still being lifted by the crane. When the truss is in the correct position, the crane will lower the truss onto the top wall.

The person then needs to remove the crane hook or chain from the truss. The crane then needs to return to the "stack" of trusses on the roof and lift another truss into position. Sometimes, these stack of trusses are on the ground and the crane will need to lift each truss into the general position and the person on top of the wall will then need to manoeuvre the truss into the final position, release the truss from the crane hook, and the process is repeated.

There is a risk of injury to a person standing on top of the wall as the person may slip, may be struck by a moving roof truss, and may be struck by the crane hook and the like.

t, nHowever, there is generally a significant advantage in being able to use the lifting 00

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crane to lift the trusses into the general position, and especially for larger and heavier trusses as it is much quicker and easier to use the crane to do so.

SHowever, there has not been available a satisfactory solution to releasing the crane I hook from the truss when the truss is on top of the wall and therefore, to date, it has Ousually be necessary to have a person standing on the wall to do so.

N It is known to have a crane hook which generally comprises a J or U shaped configuration and which can hook underneath material to be lifted. To release the material, the hook is slightly lowered and can then be swung free. Generally, this can be done without requiring a person to assist in the release process.

The problem with this type of crane hook is that the material roof truss) is not securely held by the hook. That is, if the truss is placed on the roof and the hook is inadvertently lowered further (typically only by less than 100 mm), it is possible for the hook to be released from the truss and the truss can then fall over with the possibility of causing serious injury to a person standing on the roof. Clearly therefore a safer form of hook will be one which can hold the material roof truss or something else) more securely and which can not become inadvertently released, for instance, should the hook be inadvertently further lowered.

There would therefore be an advantage if it were possible to provide a lifting hook which could lift materials (such as a roof truss), and where it would not be possible for the hook to become inadvertently released from the material and where release of the hook can be achieved without a person needing to stand on top of a roof or in another possibly dangerous position. There would be a particular advantage if the hook could be released by a person standing on the ground.

It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the 3 common general knowledge in the art in Australia or in any other country.

Object of the Invention.

00 It is an object of the invention to provide a lifting hook which can be released in a reasonably quick and reasonably safe manner.

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SIn a broad form, the invention resides in a quick release lifting hook assembly Ocomprising a first hook portion adapted to extend about part of the material to be S 10 lifted and to support the material, and a locking member which is movable between a locking position where the material is unable to be lifted out of engagement with the hook assembly and a free position where the material is able to be lifted out of engagement with the hook assembly, a release means to operate the locking member from the locking position to the free position, and a connecting member to enable the release means to be operated from a position spaced from the hook assembly.

When the locking member is in the free position, the hook assembly can be slightly lowered to lift the material out of engagement with the hook assembly.

It is preferred that the locking member comprises an elongate flexible member and therefore in another form the invention resides in a hook assembly for lifting materials such as a roof truss or something else, the hook assembly comprising a rigid body adapted to support the material to be lifted, a elongate flexible member having a portion fixed to, or relative to, the rigid body and adapted to pass about part of the material to be lifted to prevent the material from being lifted out of the hook assembly, and a release means which is movable between a locking position where the elongate flexible member is locked about part of the material, and a release position where the elongate flexible member can be released from the material, the release means being operable remotely from the hook assembly.

In this manner, a truss (or something else) can initially be on the ground and a person can easily attach the hook assembly about the truss and typically by initially releasing the elongate flexible member, attaching the rigid body about the truss and then 0 extending the elongate flexible member over the top of the truss and locking the Selongate flexible member in place. The crane can then lift the truss to the desired M position on top of the wall. Once in the desired position, and once the truss has been 00 otherwise supported, the release means can be operated to release the elongate flexible member which now allows the hook be disengaged without anybody needing to stand _on top of the roof to do so.

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N It is envisaged that the release means can be operated from the ground typically by providing a line member or something similar which is attached to the release means.

S 10 The line member can then be pulled or yanked to move the release means to the free position to allow the elongate flexible member to be released thereby allowing the hook to be removed from the truss.

In a more sophisticated form, it is envisaged that some form of electronic or other remote means may be provided to operate the release means. For instance, the release means may be operated by solenoid or something similar which can be actuated by a remote signal.

The hook assembly can be used to lift various different types of materials which 2 0 generally require to be lifted to an elevated position. It is envisaged that the hook assembly will find particular use with erection of roof trusses but it is also envisaged that the hook assembly will find use in other areas such as lifting steel or other similar items which require the safety of working from the ground.

Typically, the material to be lifted will be supported by a pair (or even more) hook assemblies which will typically be spaced apart to balance the load. As an example, figure 3 illustrates a pair of hook assemblies lifting a roof truss.

The hook assembly comprises a rigid body adapted to support the material to be lifted.

The rigid body may be made from any suitable material but, it is envisaged, that the most suitable material will be steel or some other strong metal.

The rigid body may have a configuration to support the material to be lifted. It is O therefore envisaged that the rigid body will have some form of"hook" type configuration. For instance, the rigid body may be somewhat L shaped and may Scomprise a first generally upright (in use) leg portion and a second generally 00 horizontal (in use) leg portion. To prevent the material from slipping off the rigid body, it is envisaged that the second leg portion may have some form of abutment or Sprojection to hold the material in place. Alternatively, the second leg portion may have some form of recess or channel into which the material can be placed. The second leg portion may also be curved or otherwise configured to assist in retention of the material on the rigid body.

The size of the rigid body may vary depending on the loading capacity of the hook assembly and also on the material from which the rigid body is made. If the rigid body is manufactured from steel plate, it is envisaged that the first leg portion may have a length of between 10-50 cm and the second leg portion may have a length of between 5-40 cm. It is not envisaged that the invention should be limited to a rigid body having only these dimensions, unless the context requires otherwise.

The first leg portion and the second leg portion may be somewhat rectangular when viewed in side elevation and may have at least one rounded free end or may have another type of configuration.

The width of the first leg portion and the second leg portion may vary depending on the lifting load of the hook assembly and the material from which the hook assembly is made. If the hook assembly is made from steel plate, it is envisaged that the width of each leg portion will be between 1-8 cm.

To enable incorporation of the release means, and possibly for other reasons, the rigid body may comprise a pair of members which are spaced apart and interconnected relative to each other. If desired, the release means may be positioned between these pair of spaced apart members although there may also be a variation where the release means is positioned elsewhere such as on the exterior of one or both of the members.

The spacing between the members may vary but it is envisaged that a suitable spacing will be between 10-100 mm.

The hook assembly has an elongate flexible member which, in use, prevents the hook 00 from becoming inadvertently released, and which can be remotely operated. The elongate flexible member may comprise a chain or other suitably strong member which is flexible and substantially inextensible. Alternatively, the elongate flexible 0 member may comprise a steel rope or wire or some other type of flexible member that Sis strong enough and which can be releasably operated. A suitable elongate flexible Smember will comprise a chain. Circumstances may arise where more than one (N 10 elongate flexible member is used. If so, this may comprise, for instance, a pair of chains, or a chain and something else and the like.

The length of the elongate flexible member should be sufficient to allow it to extend about the material which is supported by the rigid body and held in place. Thus, it is envisaged that the elongate flexible member will have a length of between 20-100 cm although this may vary to suit. It is also envisaged that the elongate flexible member will have one end, or one part which is permanently attached to the remainder of the hook assembly, to avoid the elongate flexible member becoming lost.

2 0 A release means is provided which can function to enable the elongate flexible member to be locked and released. Various types of release means are envisaged. It is preferred that the release means is operated manually.

The release means may be biased to a naturally locking position where the elongate 2 5 flexible member chain) can be locked, and the release means may be manipulated to a release position where the flexible member can be released. The biasing means may comprise at least one spring or other suitable member. Suitably, a pair of springs is provided. The release means may comprise an elongate member which can slide or otherwise move between the locking position and the release position. It is preferred that the release means can reciprocate between the locking position and the release position although there may be circumstances where the release means can rotate or otherwise move between these positions.

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The release means may comprise an elongate plate which may be positioned between the pair of spaced apart members. Any form of guide or slide arrangement may be provided to enable the elongate plate to slide or otherwise move between the locking 00 and the release positions. In an example, each spaced apart member may be provided with a groove or similar recess to accommodate a longitudinal edge of the elongate plate to enable the elongate plate to slide between a locking and released position.

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N The elongate plate, or another part of the release means may be provided with a Oprofile, a configuration, an attachment, or some other means to lock the elongate S 10 flexible member when the release means is in the locking position. If the elongate flexible member comprises a linked chain, the elongate plate may be provided with some form of slot or recess to engage the chain and to hold the chain against release.

Movement of the release means to the release position may cause the chain to disengage from the slot or recess thereby enabling the chain to become freed.

Of course, if the elongate flexible member comprises something else, the elongate plate, or another part of the release means may be provided with a different means to releasably lock the elongate flexible member in place. For instance, if the elongate flexible member comprises a steel rope, the release means may comprise some form of releasable clamping arrangement or something similar.

In order to increase the security of locking of the elongate flexible member in place, there may be provided another part on the hook assembly which may cooperate or otherwise operate with the release means to assist in holding the elongate flexible member in place. As an example, this part may be separate from the release means and may comprise a flap which may be able to move between an "open" position where the chain or other elongate flexible member can be more easily attached and released from the release means, and a "closed" position where the chain (or other elongate flexible member) is held in the locked position.

The release means can be operated at some distance from the hook assembly which means that the release means can be operated from a person standing on the ground while the hook assembly is holding a truss on top of a wall. It is envisaged that some b O form of connecting member will be provided between the hook assembly and the person standing on the ground or being positioned some distance away from the hook Sassembly. In a simple form, the connecting member will comprise a rope, or any 00 other type of flexible line member a chain). The connecting member may also comprise a relatively rigid rod or something similar that can be operated by the person. It is envisaged that the most convenient type of connecting member will comprise a rope. The rope may have any suitable length which will depend on where r the hook assembly is relative to the person and it is envisaged that the rope should have a length of between 2-6 m.

N Brief Description of the Drawings.

An embodiment of the invention will be described with reference to the following drawings in which:.

Figure 1. Illustrates a hook assembly attached to a truss and in the "locking" position.

Figure 2. Illustrates the hook assembly of figure 1 in the "release" position where the hook can be removed from the truss.

Figure 3. Illustrates a truss being supported by a pair of spaced apart hook assemblies.

Figure 4. Illustrates a close up of the hook assembly in the position where the elongate flexible member (linked chain) can be locked in place.

Figure 5. Illustrates the hook assembly of figure 4 in the "locked" position but without showing the chain.

Figure 6. Illustrates the hook assembly in the "released" position where the chain (not illustrated) can be released (this position also being illustrated in figure 2).

Figure 7. Illustrates the hook assembly in the "locked" position this time illustrating the chain.

Figure 8. Illustrates a side view of the hook assembly of figure 7 in the "locked" 3 0 position.

Figure 9. Illustrates a close up view of the release means which comprises a spring biased sliding plate having a forward slot into which the chain can be held.

Figure 10. Illustrates the main components of the hook assembly illustrating the Or O relatively simple yet highly effective design.

_n Best Mode.

00oO Referring to the illustrations and initially to figures 1-3, there is illustrated a hook assembly 10 for lifting materials such as a roof truss 11. The hook assembly comprises a rigid substantially L-shaped body 12 which, in the embodiment, Scomprises a pair of spaced apart L-shaped members 13, 14 (one member 13 being illustrated in figure 10), and other illustrations (for instance figure 9) illustrating both N 10 members 13, 14. Each L-shaped member is made of plate steel having a thickness of about 5 mm. each L-shaped member comprises a first generally upright portion (see for instance figure 10), and a second generally horizontal portion 16 (see figure in use. Upright portion 15 and generally horizontal portion 16 are also illustrated in various other illustrations including figure 2. The first portion 15 has a length of between 20-40 cm and the second portion 16 is slightly shorter having a length of between 10-30 cm. In the particular embodiment, portion 15 and portion 16 are at right angles to each other and formed from a single plate of material as illustrated in figure 10. Each portion has a width of between 2-10 cm.

Each L-shaped member 13, 14 (see for instance figure 10) is provided with a series of openings which comprise round openings and elongate openings. The reason for these openings will be described in greater detail below.

The L-shaped members 13, 14 are spaced apart by a distance of between 10-50 mm and this is achieved by a number of strong bolts which pass through some of the round openings illustrated in figure 10. In the particular embodiment, and possibly best illustrated in figure the two L-shaped members are held together by four main bolts 18-21. A sleeve or collar is provided between the spaced apart L-shaped members to hold the members rigidly together.

In the particular embodiment, the lower portion 16 of each L-shaped member is provided with a small abutment to stop material from simply sliding off portion 16.

The abutment comprises a small metal plate 22 (see figure 10) which is bolted to each i U O portion 16 of each L-shaped member. Thus, two metal plates 22 are provided. These metal plates 22 are illustrated in various figures and referenced in figure 4 figure 8 and Sfigure 10. Each metal plate has a length of between 4-10 cm and is bolted by two 00 bolts on each portion 16. The advantage of this is that the metal plates can be quite easily removed and replaced by longer or differently configured plates depending on the material that is to be lifted.

A release means is provided between the pair of spaced apart L-shaped members 13, 14 and mainly in the upper portion 15. The release means is best illustrated in figures N 10 4-6 and also figure 9 and figure 10. Referring initially to figure 10, the release means comprises a metal plate 23. Metal plate 23 contains small extending tabs 24 extending from each longitudinal edge of the metal plate. These tabs 24 are adapted to slide within the elongate slots 25 on each L-shaped member 13, 14.

Referring to figures 4-6, metal plate 23 is illustrated in position between the spaced apart L-shaped members 13, 14. The "upper" end of metal plate 23 contains an open ended slot 26 which is referenced in figure 5 and figure 10. Slot 26 functions to engage against the elongate flexible member which, in the particular embodiment, comprises a linked chain 27. Chain 27 is referenced in figure 8 and figure 7 at least.

In figure 7, there is illustrated chain 27 having one link inserted in the slot 26 on the front of plate 23. Figures 4-6 illustrates the arrangement without the chain.

Plate 23 can move between a "forward" chain locking position illustrated in figure 7, figure 8, figure 4 and figure 5, and a pulled back or "retracted" free position illustrated at least in figure 6 (and also in figure Plate 23 is biased into the forward locking position figure 5) by a pair of springs 28 which are illustrated in figure 9.

Springs 28 have a lower end attached to a lower part of plate 23 and an upper part attached to a pin 29 which extends between members 13, 14 and through one of the round openings in each member. Thus, the springs function to "pull" plate 23 into the forward locking position illustrated at least in figure Plate 23 can be pulled downwardly into the retracted position by a connecting member which, in the particular embodiment, comprises a nylon rope 30 which is illustrated in

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figure 1 and figure 2. Nylon rope 30 is attached to a metal coupling 31 on the lower Send of plate 23 and the metal coupling 31 is illustrated at least in figure 5. The retracted position of plate 23 is illustrated at least in figure 6.

00 The hook assembly of the particular embodiment comprises a further component which is a metal flap 32. Metal flap 32 is illustrated in various figures including afigure 4, figure 5, figure 6 and figure 7. Flap 32 can move between a closed position ri illustrated in figure 5 and figure 7 and a pivoted away open position illustrated in Ofigure 4 and figure 6. The flap 32 is pivotally attached between the L-shaped S 10 members 13, 14 and is not attached to plate 23.

The function of the flap will be described with reference to figures 4-6 and figure 7, and is basically designed to prevent the chain from inadvertently being removed from the slot 26 in the front of plate 23. To explain, initially, the hook assembly 10 can be lowered to ground level and a truss 11 (or something else) can be placed in an upright position (while still on the ground). The horizontal portion 16 of the hook can then be placed underneath a portion of the truss (see figure All this can be done while the person is standing on the ground. Once the hook is placed underneath the portion of the truss, the chain 27 can extend over the top of the truss (see figure 1) and a portion of the chain can be pushed into slot 26 on plate 23. Referring now to figure 7, it can be seen that once particular chain link is positioned in the slot, the next chain link will prevent the chain from being further pulled through the slot. The function of flap 32 now becomes apparent as flap 32, when in the closed position (see figure closes the otherwise open end of the slot 26 and prevents the chain from being removed.

The chain is now securely locked in place.

When the release means (plate 23) is pulled downwardly to the position illustrated in figure 6, it will now be sufficiently far away from the flap to allow the chain to be lifted out of the slot and released. The flap will usually remain in the closed position when the release means is operated.

As illustrated at least in figure 4 and figure 6, the flap 32 can be pivoted to an open position and this position makes it easier to initially thread the chain into the slot.

Thus, when initially attaching a truss, rather than needing to strongly pull down the release means (plate 23) to provide sufficient opening to push the chain link into slot 26, the release means can instead stay in the naturally extended position and the flap 00 can be pivoted to the open position (see figure 4) which provides enough room to allow the chain to be inserted into the slot. Once the chain is in position (that is the locked position), the flap can be rotated back to the closed position (see figure 5 and Sfigure 7) and the chain can not be removed.

OWhen the hook assembly is in the elevated position (see figure 1) and the chain is in I 10 the locked position (also figure the rope 30 can be pulled which will retract the release means (plate 23) to pull the release means away from the flap. To assist in the release of the chain from slot 26, the bolt 19 is strategically positioned (best illustrated in figure 6) such that when the plate 23 is pulled back, the chain 27 will be held back by being positioned above bolt 19 and will be forced out of slot 26.

Once that occurs, the hook assembly can be swung away from the truss (see figure 2) and in doing so, the released chain will be pulled out of the upper part (15) of the hook assembly. The other end of the chain is bolted or otherwise securely attached to the end of the lower part 16 of the hook assembly as illustrated in figure 2.

The hook assembly can then be lowered to ground level and another truss can be attached in the manner described above and lifted into position and the hook assembly can be released by yanking on rope 30, and pulling back the hook assembly to make the chain slide out of engagement with the upper part 15 of the hook assembly.

The arrangement provides a high degree of security as, when the chain is locked in position, it is almost impossible for the chain to become inadvertently released.

However, the chain can be quite easily released by yanking on rope Throughout the specification and the claims (if present), unless the context requires otherwise, the term "comprise", or variations such as "comprises" or "comprising", will be understood to apply the inclusion of the stated integer or group of integers but not the exclusion of any other integer or group of integers.

13 SThroughout the specification and claims (if present), unless the context requires otherwise, the term "substantially" or "about" will be understood to not be limited to 00 the value for the range qualified by the terms.

Any embodiment of the invention is meant to be illustrative only and is not meant to be limiting to the invention. Therefore, it should be appreciated that various other C changes and modifications can be made to any embodiment described without 1^ departing from the spirit and scope of the invention.

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Claims (17)

1. A hook assembly for lifting material such as a roof truss, the hook O M 5 assembly comprising a rigid body adapted to support the material to be lifted, a elongate flexible member having a portion fixed to, or relative to, the rigid body and adapted to pass about part of the material to be lifted to prevent the material from being lifted out o of the hook assembly, and a release means which is movable between a locking position where the elongate flexible member is locked about part of the material, and a release o 10 position where the elongate flexible member can be released from the material, the C release means being operable remotely from the hook assembly. Cl

2. The assembly as claimed in claim 1 wherein the release means can slide between the locking position and the release position.

3. The assembly as claimed in any one of the preceding claims, wherein the release means is biased to adopt the naturally locking position.

4. The assembly as claimed in any one of the preceding claims, comprising a connecting member operatively attachable to the release means to enable the release means to be moved from the locking position to the release position.

The assembly as claimed in claim 4, wherein the connecting member comprises a line member.

6. The assembly as claimed in any one of the preceding claims, wherein the hook assembly is substantially L shaped comprising an upright portion and a substantially horizontal portion.

7. The assembly as claimed in claim 6, wherein the substantially horizontal portion contains an abutment, to facilitate retention of the material on the substantially horizontal portion. C o

8. The assembly as claimed in claim 7, wherein the abutment comprises a plate which is releasably attachable relative to the horizontal portion.

9. The assembly as claimed in any one of the preceding claims comprising a 0 M 5 pair of spaced apart substantially L-shaped members which are attached relative to each other. (N o

10. The assembly as claimed in claim 9, wherein the release means comprises an elongate plate which is positioned between the L-shaped members and is o 10 adapted for sliding movement between the locking position and the release position. C

11. The assembly as claimed in any one of the preceding claims, wherein the elongate flexible member comprises a linked chain.

12. The assembly as claimed in claim 10 and claim 11 wherein the elongate plate is provided with a open ended slot to accommodate a link of the linked chain to lock the chain in position.

13. The assembly as claimed in claim 12, comprising a flap which is separate from the elongate plate and which is attached relative to the L-shaped members, the flap being movable between an open position and a closed position, the flap, when in the closed position, closing the otherwise open end of the slot in the elongate plate, and when in the open position, allowing the chain to be lifted out of the slot.

14. The assembly as claimed in any one of claims 3-13, wherein the release means is biased by a spring.

A method for remotely releasing material retained by a lifting hook assembly, the method comprising attaching the material to the hook assembly, the hook assembly comprising a first part which is substantially rigid, and a second part which comprises a flexible elongate member, the second part being movable between a free position where the material can be removed from the first part, and a locking position where the material cannot be removed from the first part, release means to move the 16 O O flexible elongate member from the locking position to the free position, lifting the material via the hook assembly to a desired position, and remotely operating the release means to enable the material to be removed from the hook assembly from a remote Q position. e3

16. A quick release lifting hook assembly comprising a first hook portion adapted to extend about part of the material to be lifted and to support the material, and O a locking member which is movable between a locking position where the material is unable to be lifted out of engagement with the hook assembly and a free position where O 10 the material is able to be lifted out of engagement with the hook assembly, a release 0,1 means to operate the locking member from the locking position to the free position, and a connecting member to enable the release means to be operated from a position spaced from the hook assembly.

17. A hook assembly substantially as hereinbefore described with reference to the accompanying illustrations. DATED: 30 MARCH 2007