WO2002004335A1

WO2002004335A1 - Release mechanism

Info

Publication number: WO2002004335A1
Application number: PCT/GB2001/003173
Authority: WO
Inventors: David Stewart Hamilton
Original assignee: Hamiltons Safety Enhanced Tools Limited
Priority date: 2000-07-12
Filing date: 2001-07-11
Publication date: 2002-01-17
Also published as: AU2001270824A1

Abstract

A load-supporting means suitable for use on a crane or lifting mechanism comprises an elongate support (2), a hook (1) suspended therefrom, said hook (1) being provided with ejector means (13) mounted around the elongate support (2), the control means (3) controlling the operation of the ejector means (13) of the hook (1), the arrangement being such that the control means (3) is mounted around the elongate support (2) at a location that is above said hook (1) and ejector means (13), and such that the weight of a load carried by the hook (1) depends from and is supported substantially only by the elongate support (2) whereas substantially no weight is carried by the control means (3). The hook (1) can be laid on a deck or floor to stop the hook (1) swinging around while leaving the control means (3) hanging upright and fully accessible for maintenance or repair. Since the control means (3) does not carry load weight, the control means (3) can be much lighter and cheaper than prior art arrangements wherein a hook release control unit has to carry the weight of a load.

Description

RELEASE MECHANISM

This invention relates to hooks and load-supporting means, and relates more particularly but not exclusively to release mechanisms suitable for use with equipment such as, for example, lift or crane hooks and to the control means of such equipment .

Release mechanisms for lift or crane hooks are generally well known. For example, US patent no. 4,416,480 describes a pneumatic release mechanism for a load hook in which the hook depends from the free end of a chain or cable which itself depends from the underside of a control module of the release mechanism. Upon receipt of a signal from a portable radio transmitter, the control module of the release mechanism is activated and transfers air from a compressed air reservoir through air line connections to retract a latch pin in the hook and thereby allow the hook to rotate to release the load.

A further release mechanism for a hook is described in GB-A-2,293,407 which shows a crane hook with a remotely controlled ejection lever. The sliding ejection lever fits into a hollow elongate shank member and is operated by a hydraulic cylinder which is remotely controlled by the user. A power source, drive means and control means are all provided within the shank member, above the hook. When it is required to release a load from the hook, the control means is activated via the remote control unit held by the operator. The control means activates the power source which causes the hydraulic unit attached to the shank member to selectively force hydraulic fluid into a hydraulic cylinder. This movement of hydraulic fluid forces a piston out of the cylinder and subsequently moves an ejection lever with the shank member thereby releasing the load.

Whilst release mechanisms of the type described above have been known for some time, and have been found to be useful in relation to personnel safety, the loads carried on the hooks are often considerable, being in the range of approx. 1 tonne to 250 tonnes. As the hook depends from the underside of the control unit, not only must the hook itself meet the requirements of being capable of lifting such a load, but the control unit must also be capable of carrying such a load suspended therefrom. This either puts an artificially low limit on the load which can be carried by the hook or alternatively, results in a large, heavy, unwieldy control mechanism which must be lifted together with the load whenever the hook is in operation. Moreover, load- lifting equipment incorporating such hooks, release mechanisms, and their control means is commonly employed on ocean-going vessels, for example in offshore exploration and production of hydrocarbons. On-deck maintenance and repair of such load-lifting equipment may be necessary from time to time, and may be especially hazardous in stormy weather and/or rough seas . Prior art arrangements in which control mechanisms are closely adjacent release mechanisms had either to remain suspended, with consequent risk of swinging into injurious contact with repair personnel (unless omnidirectionally tethered) , or such arrangements had to be fully lowered to the deck, such that the control mechanism was lying sideways (instead of remaining in its normal upright position) and the lower side of the control mechanism became more or less inaccessible. Similarly, the hook of prior art arrangements could not be lowered nearly to deck level (or to ground level) for the attachment of the hook to a load resting on the deck (or on the ground) without concomitantly lowering the control means to the same level with consequent risk of the control means interfering with load attachment and/or risk of collision of the control means with the load or with adjacent items.

The present invention aims to provide improved hooks and load-supporting means in which the above disadvantages are overcome or at least mitigated.

According to one aspect of the present invention there is provided a load-supporting means suitable for use on a crane or lifting mechanism, said load-supporting means comprising an elongate support, a hook suspended from said elongate support, said hook being provided with ejector means for selectively ejecting a load from said hook, and control means mounted around the elongate support, the control means controlling the operation of the ejector means of the hook, characterised in that the control means is mounted around the elongate support at a location that is above said hook and ejector means, and in that the weight of a load carried by the hook depends from and is supported substantially only by the elongate support whereas substantially no weight is carried by the control means . This arrangement allows the control means to be reduced in size and weight (in comparison to prior art arrangements) because the control means does not have to be of a sufficient size and weight to support the weight of a load carried by the hook and the elongate support. This reduces the overall size and cost of the equipment required for lifting the loads, as discussed earlier. Moreover, this arrangement separates the control means from the hook and ejector means such that the hook and ejector means can be lowered to a deck (or workshop floor) while keeping the control means suspended and fully accessible in an upright position; this advantage is facilitated if the elongate support is flexible (e.g. in the manner of a cable or rope) or articulated (e.g. in the manner of a chain) at least in the portion of the elongate support above the hook and below the control means. The full length of the elongate support may be rigid or flexible or articulated.

Advantageously, the control means is removably mounted around the elongate support.

Preferably, the control means comprises a housing formed of a hollow tubular member that allows through passage of the elongate support, the tubular member being provided at either end with an end plate.

Conveniently, the control means further comprises a cover which is slidably retained over the hollow tubular member and between the end plates such as to shield the control means during use, the cover being removable to allow access to the control means for maintenance or repair.

Alternatively, the control means is formed in a plurality of sections which are connectable together to surround the elongate support .

Advantageously, each of the sections of the control means performs a distinct control function thereby allowing a single section of the control means to be selectively removed from around the elongate support, for example for replacement or repair.

Conveniently, fixing means are provided to retain the various sections of the control means in respective positions collectively surrounding the elongate support. This also allows the control means to be retro-fitted to a currently used elongate support .

Conveniently, two collars are provided for surrounding the elongate support, one said collar being disposed at each end of the control means . This provides additional stability to the device.

Advantageously, the control means comprises power supply means for driving the ejector means of the hook. Preferably, the power supply means is in the form of a dry cell battery rechargeable in connection with a self- charging hydraulic accumulator. Alternatively, where a non-electrical power supply is necessary or desirable, the power supply may be a container of compressed gas, e.g. highly compressed nitrogen.

Advantageously, the ejector means is in the form of a hydraulic ram provided within the hook, the operation of said hydraulic ram being energised by the power supply means .

Conveniently, the release mechanism further comprises a hand-held remote control transmitter which sends a control signal to a receiver in the control means for operation of the power supply selectively to energise the ejection means of the hook. According to a further aspect of the present invention there is provided a hook for supporting a load, said hook comprising coupling means to couple the hook to a lifting mechanism and release means selectively operable to release the load from the hook wherein the release means comprises a guillotine which is off-set from the lifting mechanism to which the hook is coupled such that the weight of a load carried by the hook is not transmitted through the guillotine when the release means is not being operated.

According to a still further aspect of the present invention, there is provided a hook for supporting a load, said hook comprising coupling means to couple the hook to a lifting mechanism and release means selectively operable to release the load from the hook wherein a latch is provided selectively to close the hook to prevent snagging of the hook on surrounding equipment .

In the further and still further aspects of the invention, said release means may comprise ejection means selectively operable positively to cause ejection of a load from the hook.

Embodiments of the present invention will now be described by way of example with reference to the accompany drawings in which: -

Figure 1 shows a schematic view of a release mechanism according to one aspect of the present invention;

Figure 2 shows a perspective view of a control means adapted for use in the present invention; Figure 3 shows a cross-sectional view of the control means of Figure 1 ;

Figure 3A shows a cross-sectional view of an alternative form of the control means of Figure 1;

Figure 4 shows a schematic side view of the release hook of the present invention with the guillotine in a first position;

Figure 5 shows the release hook of Figure 4 with the guillotine in a second position; and

Figure 6 shows the release hook of Figure 4 with the face plate mounted thereon and the latch substantially in a closed position.

Turning to the drawings, Figure 1 shows a schematic view of an embodiment of load-supporting means in accordance with the invention, the embodiment including a release mechanism for transfer of loads from one location to another. The release mechanism comprises a remotely controlled release hook 1 (further described below) which is secured to the lower end of an elongate support 2 such as, in the example illustrated, a flexible wire rope or a fixed strap or a rigid tie-rod or a chain or the like. The strength of the elongate support 2 determines the weight of a load which can be lifted by the hook 1. The upper end of the elongate support 2 is suspended from a crane or winch or hoist or the like (not shown) to enable lifting of the load for transfer of the load between different locations. A control means 3 is mounted around the elongate support 2 for controlling the operation of the release hook 1, the control means 3 being at a location that is above the hook 1 and its release mechanism. The release mechanism is quiescent during attachment of the load to the hook 1, and during subsequent lifting of the load, but when the load is to be detached from the hook 1, the release mechanism is operated under the control of the control means 3 (as will be detailed below) so as to eject the load from the hook 1.

Figure 2 shows a perspective view of the control means 3 of the release mechanism of Figure 1. The control means 3 comprises a substantially cylindrical housing 4 which is adapted to surround the elongate support 2 of the release mechanism. A through bore 5 is provided axially through the housing 4, the through bore 5 being of a suitable diameter that allows through passage of the elongate support 2.

The outer surface 6 of the housing 4 is provided with a plurality of triangular apertures 7. In the embodiment shown in Figure 2, four apertures 7 are equi- spaced around the housing 4, although some number of apertures 7 other than four may be employed as required. The apertures 7 are widest at the outer surface 6 of the housing 4 and taper to a point towards the centre of the housing 4.

The individual components which make up the control means 3 are distributed around the housing 4 and are mounted within the apertures 7 therein. For example, standard equipment in the form of an antenna and receiver for sending and receiving signals from a remote control unit (not shown) which is operated by the user may be supplied. The control means 3 may also comprise a battery or other suitable power supply means, a motor, a hydraulic pump and an accumulator. (If the control means 3 is to be non-electrical, e.g. for intrinsic safety, the power supply means may be a container of compressed gas as a non-electrical substitute for a battery) .

In an alternative version of the control means 3 as shown in Figure 3A, the control means 3 comprises a body 20 having a hollow tubular member 21 mounted between two substantially circular end plates 22. In use, the end plates 22 function as platforms to support components of the control means 3 to be described further below. One or more additional platforms 23 may be provided surrounding the tubular member 21 between the two end plates 22. In the embodiment shown in Figure 3A one further such platform is illustrated.

A tank 24 of hydraulic fluid is provided adjacent the upper end plate 22 and appropriate connections are provided for charging of equipment on site.

The components of the control means 3 for the release mechanism may comprise one or more batteries, a pump, accumulators, a manifold and appropriate telemetry.

A tubular cover member 25 is slidably mounted over the tubular member 21 between the two end plates 22 so as to enclose the components of the control means 3 to prevent damage occurring during use whilst allowing access to the components for maintenance or repair.

The outer edges of the upper and lower end plates 22 may be shrouded by annular rubber buffers 26 to inhibit damage to the control means 3 in the event of the control means colliding with other equipment, e.g. during stormy weather conditions.

In the embodiment of control means 3 shown in Figure 3A, the batteries of the control means 3 are provided on one of the circular platforms 23 mounted around the tubular member 21 between the two end plates 22. In the event that the batteries require replacement, the cover member 25 can be slid down to the surface of the battery- mounting platform 23 in order to expose the batteries whilst the remaining elements of the control means 3 remain shielded by the cover member 25. Once the batteries are repaced, the cover member 25 can be slid back up into its operating position between the two end plates 22.

In the event that further maintenance is required, the cover member 25 can be slid down over the lower end plate 22 to allow complete access to the control means 3 for full maintenance.

In an alternative arrangement, the batteries may be replaced by an alternative power source such as compressed Nitrogen gas. A storage tank would be provided within the control means to hold the Nitrogen gas under pressure. A suitable supply and delivery system would control the flow of Nitrogen. This arrangement would be particularly suitable for use in an off-shore environment to comply with safety regulations.

The elongate support 2 from which the hook 1 depends is mounted so that it passes through the hollow tubular member 21 and ensures that the weight of any load is placed exclusively on the elongate support 2 and is not carried by the control means 3.

Turning now to Figures 4-6, the release hook 1 comprises a generally rectangular body 8 which is provided at the upper end thereof with means 9 to connect the hook 1 to the elongate support 2 (as shown in Fig. 1 but not shown in Figs. 4-6), and at the lower end with release means selectively operable to release a load from the hook 1.

The connecting means 9 may comprise an aperture provided adjacent the upper end of the hook 1, through which the free end of the elongate support 2 extends. The body 8 of the hook 1 may be shaped around the aperture 9 so as to increase the strength of the body 8 at that point. In the embodiment shown, the upper part 10 of the body 8 of the hook 1 is arcuate in the vicinity of the aperture 9. Guard means 30 (Fig. 6) may also be mounted on the upper portion of the hook 1 to protect connection points 14C (Figs. 4 & 5) for hoses carrying hydraulic fluid from the tank 24 on the control means 3 for activating the hook 1.

The lower end of the body 8 of the hook 1 is generally C-shaped to provide an opening 11 in one side of the hook 1 to allow a load to be introduced onto the hook 1 and be suspended therefrom. The opening 11 is envisaged to be of a suitable size and configuration as to allow more than one load to be carried by the hook 1 at the same time.

The lower edge of the body 8 adjacent the opening 11 is provided with a raised lip 12 such that when a load is introduced onto the hook 1, the load is retained on the hook 1, in the first instance, by the lip 12.

The outer face of the hook body 8 , below the opening 11, is provided with an integrally formed spur 31 (Fig. 6) which projects beyond the outer face of the hook body 8 as will be described further below.

The hook 1 further comprises a guillotine 13 for selectively releasing a load from the hook 1. The guillotine 13 is off-set from the lifting mechanism described above such that the weight of a load carried by the hook 1 is not transmitted through the guillotine 13 and therefore the guillotine 13 does not take any strain when not operating to release a load. This allows the hook 1 to be lighter which gives a significant saving in materials over prior art devices.

The guillotine 13 comprises a flat plate which is slidably mounted on one side of the hook body 8. Guide means (not shown) are provided on the side of the body 8 within which the guillotine 13 is slidably received to allow the guillotine 13 to be raised and lowered upon the body 8 of the hook 1. Controlled raising and lowering of the guillotine 13 is accomplished by selective pressurisation (via hose connection points 14C) of a piston and cylinder assembly 14 that is built in to the hook body 8, the cylinder being secured to the body 8, and the piston being coupled (by means not shown) to the guillotine 13 for conjoint movement of the piston and guillotine .

The guillotine 13 is also substantially C-shaped and in the lower position within the hook body 8, the guillotine 13 generally surrounds the opening 11 of the body 8.

The lower portion of the guillotine 13 has an upper face 15 which slopes downwards from the mid-width of the hook body 8 towards the side of the hook 1 containing the opening 11. As the guillotine 13 is selectively raised to bring its lower portion, with its upper face 15, upwards towards the opening 11, a load is lifted clear of the lip 12 of the hook, slides (under gravity) down the sloping face 15 of the guillotine 13, and is thus ejected through the opening 11 and out of the hook 1.

It is to be noted that in the present invention, the guillotine 13 is formed as a single body slidably mounted within the hook whereas in prior art hooks, an equivalent guillotine is generally formed of a two-part body centred in the respective hook.

A face plate 16 is mounted over the outside of the hook 1 as shown in Figure 6 and the guillotine 13 slides vertically between the inner body 8 of the hook 1 and the outer face plate 16.

An outwardly opening latch 17 is pivotally mounted upon the upper part 10 of the hook body 8. The latch 17 depends from the upper part 10 of the hook body 8 over the opening 11 in the side of the hook 1. The latch 17 is selectively operable to open or close the hook 1 to allow loads to be introduced to the hook 1, and to allow the guillotine 13 selectively to eject a load from the hook 1. The latch 17 also acts to guard against snagging of the hook 1 on surrounding equipment as the hook 1 is being moved from one position to another. While the latch 17 is in its closed position, the hook 1 cannot become entangled with cables or equipment as they will be deflected by the closed latch 17 and thereby prevented from entering the opening 11 in the side of the hook 1. It is envisaged that such a latch 17 could be provided on any form of release hook in order to prevent such snagging of the hook occurring.

The free end of the latch 17 is adapted to cooperate with the upper surface of the spur 31 (Fig. 6) on the outer face of the body 8 of the hook 1 when the latch 17 is in its closed position. Thus, when the latch 17 is closed, the free end of the latch 17 does not extend beyond the front face of the hook body 8 which thereby offers protection to the latch 17 and prevents the free end of the latch 17 from snagging on equipment nearby and opening unintentionally.

A handle 32 may be provided on the hook body 8 to enable the hook 1 to be safely grasped by an operator to facilitate placing of loads onto the hook 1. In the embodiment shown in Fig. 6, the handle 32 is provided on the rear face of the hook 1, remote from the opening 11.

In use of the device, the release hook 1 is mounted on the lower end of the elongate support 2, and the housing 4 of the control means 3 for the hook 1 is mounted around the elongate support 2 at a location above the hook 1 and its load ejector mechanism such that the weight of a load placed on the hook 1 is not transmitted through the control means 3. The elongate support 2 may be passed through the bore 5 in the housing 4 or alternatively, the housing 4 may be formed in sections, the sections being mounted around the elongate support 2 and held in position by suitable fixing means such as one or more removable collars (not shown) .

With the embodiment of the control means 3 as shown in Figure 3A, the elongate support 2 is passed through the hollow tubular member 21 and the hook 1 is then connected to the lower end of the elongate support 2.

Means (not shown) may be provided to retain the control means 3 in a desired position above the release hook 1 and its load ejector mechanism.

A hydraulic hose or umbilical (not shown) is then connected between the control means 3 and the hose connection points 14C for the piston/cylinder assembly 14 in the release hook 1 for transmitting hydraulic fluid to the piston/cylinder assembly 14 selectively to operate ejector mechanism 13+14 of the hook 1 to capture or release a load therefrom as described above.

Operation of the release hook 1 is controlled by a user remote from the release hook 1 which allows the load to be released safely and without danger to the user. A remote controlled, hand-held transmitter (not shown) is used to send a suitable radio signal to the receiver of the control means 3. Upon receipt of this radio signal, the motor in the control means 3 is actuated which in turn controls the hydraulic pump to transfer hydraulic fluid through the hydraulic hose or umbilical to and from the piston/cylinder assembly 14 that raises and lowers the guillotine 13 of the hook 1 . (As an alternative to the guillotine 13 or other means that positively ejects a load from the hook 1, means (not shown) may be substituted that selectively permits a load to leave the hook without positive ejection) .

As the control means 3 is not mounted in direct line between a crane and the load such that the control means 3 does not carry the weight of a load, the control means 3 does not have to be able to withstand the lifting loads generally placed thereon in known mechanisms where the control means are provided directly around or closely adjacent the release hook. Therefore both the size and weight of the control means in the present invention can be substantially reduced in comparison to known releasing mechanisms. This allows for a substantial reduction in the overall size and weight of the releasing mechanism itself without reducing the load which can be safely carried thereon.

This reduction in size and weight of the control means 3 is especially important when considering the operation of the releasing means on board a vessel or in an off-shore environment where available space is at a premium and the weight of the equipment must be closely monitored at all times to comply with safety regulations. Furthermore, a reduction in the size of the control means allows for easier storage of the control means when the equipment is not is use.

All of the above factors lead to a reduction in the overall costs of the release mechanism and of its control means, together with improved safety.

Claims

1. A load-supporting means suitable for use on a crane or lifting mechanism, said load-supporting means comprising an elongate support, a hook suspended from said elongate support, said hook being provided with ejector means for selectively ejecting a load from said hook, and control means mounted around the elongate support, the control means controlling the operation of the ejector means of the hook, characterised in that the control means is mounted around the elongate support at a location that is above said hook and ejector means, and in that the weight of a load carried by the hook depends from and is supported substantially only by the elongate support whereas substantially no weight is carried by the control means .

2. A load-supporting means as claimed in claim 1, wherein the elongate support is flexible or articulated at least in the portion of the elongate support above the hook and below the control means .

3. A load supporting means according to claim 1 or claim 2, wherein the control means is removably mounted around the elongate support.

4. A load supporting means according to any preceding claim, wherein the control means comprises a housing formed of a hollow tubular member that allows through passage of the elongate support, the tubular member being provided at either end with an end plate .

5. A load supporting means according to claim 4, wherein the control means further comprises a cover which is slidably retained over the hollow tubular member and between the end plates such as to shield the control means during use .

6. A load supporting means according to any of claims 1-4, wherein the control means is formed in a plurality of sections which are connectable together to surround the elongate support .

7. A load supporting means according to claim 6, wherein each of the sections of the control means performs a distinct control function thereby allowing a single section of the control means to be selectively removed from around the elongate support for replacement or repair.

8. A load supporting means according to claim 7, wherein fixing means are provided to retain the various sections of the control means in respective positions collectively surrounding the elongate support.

9. A load supporting means according to any one of claims 6-8, wherein two collars are provided for surrounding the elongate support, one said collar being disposed at each end of the control means.

10. A load supporting means according to any one of the preceding claims, wherein the control means comprises power supply means for driving the ejector means of the hook.

11. A load supporting means according to claim 10, wherein the power supply means is in the form of a dry- cell battery rechargeable in connection with a self- charging hydraulic accumulator.

12. A load-supporting means according to claim 10 wherein the power supply means is in the form of a container of compressed gas.

13. A load supporting means according to any one of claims 10-12, wherein the ejector means is in the form of a hydraulic ram provided within the hook, the operation of said hydraulic ram being energised by the power supply means .

14. A load supporting means according to any one of claim 10-13, wherein the release mechanism further comprises a hand-held remote control transmitter which sends a control signal to a receiver in the control means for operation of the power supply selectively to energise the ejection means of the hook.

15. A load supporting means substantially as hereinbefore described with reference to and as shown in Figures 1, 2, and 3, or in Figure 3a, of the accompanying drawings .

16. A hook for supporting a load, said hook comprising coupling means to couple the hook to a lifting mechanism and release means selectively operable to release the load from the hook wherein the release means comprises a guillotine which is off-set from the lifting mechanism to which the hook is coupled such that the weight of a load carried by the hook is not transmitted through the guillotine when the release means is not being operated.

17. A hook for supporting a load, said hook comprising coupling means to couple the hook to a lifting mechanism and release means selectively operable to release the load from the hook wherein a latch is provided selectively to close the hook to prevent snagging of the hook on surrounding equipment .

18. A hook as claimed in claim 16 or claim 17, wherein said release means comprises ejection means selectively operable positively to cause ejection of a load from the hook.

19. A hook substantially as hereinbefore described with reference to and as shown in Figures 4, 5, and 6 of the accompanying drawings .