Field of the Invention

This invention relates to a grapple assembly configured for suspension from a helicopter. In preferred embodiments the invention may be used to transport logs or waste materials such as slash in forestry applications.

Background of the Invention

Forestry activities frequently occur in remote and inaccessible locations. Trees need to be felled and de-limbed, then logs need to be removed from terrain which can be remote, steep and which may have limited road access. Waste materials such as slash - such as that created by de-limbing logs - should also be removed from the forest as part of forestry activities. If not removed slash can be washed into waterways and on to beaches by large scale rain events, potentially blocking water ways, damaging infrastructure, polluting beaches and creating a maritime hazard.

Prior art attempts have been made to use helicopters in these applications to remove logs to a more accessible or convenient collection point. A representative example of the prior use of a helicopter mounted log grapple is described in US patent specification US6418989.

Pre-existing helicopter deployed grapples are very specialised equipment and normally require helicopters to be modified or reconfigured to use them. Hydraulic based drive systems used to open and close the grapple jaws need to be supplied with pressurised hydraulic fluid from the helicopter, requiring fluid lines to be run to the grapple in combination with a support cable. Furthermore, as is case with the grapple assembly described in US patent US6418989, two separate connection points and suspension cables need to be used to connect the grapple to the helicopter for effective operation of the grapple.

These requirements therefore limit the utility of these existing helicopter grapples as a specially modified helicopter must be available to use them. In addition the need for hydraulic fluid supply lines and potentially for additional suspension cables run between the helicopter and the grapple increases the weight which must be borne by the helicopter. This limits the payload which can be lifted by the helicopter and accentuates safety issues caused by the need to suspend additional lines from the helicopter. Furthermore the weight of these extra lines changes the distribution of mass experienced by the helicopter, complicating flying operations. It would therefore be of advantage to have improvements in the field of grapple assemblies configured for use with helicopters. In particular an improved grapple assembly which could be wirelessly controlled and which exhibited a self-contained character would be of advantage. An improved grapple assembly with a robust and lightweight design would be of advantage, as would a grapple assembly which could be suspended only from the cargo hook of a helicopter which did not require specialised retrofitting or modification.

Disclosure of the Invention

According to one aspect of the present invention there is provided a grapple assembly configured for suspension from a helicopter cargo hook, the grapple assembly including a support frame which includes a cargo hook connector, a pair of opposed grapple jaws pivotally connected to the support frame, a hydraulic drive ram connected at opposite ends to each of the pair of grapple jaws, a hydraulic fluid reservoir connected to a pump, the pump and hydraulic fluid reservoir being configured to supply and remove hydraulic fluid from the hydraulic drive ram, a hydraulic controller being configured to transmit command signals to the pump, at least one battery configured to supply electrical energy to the hydraulic controller and the pump, wherein the hydraulic fluid reservoir, pump, hydraulic controller and the at least one battery are mounted to and supported by the support frame.

According to another aspect of the present invention there is provided a grapple assembly configured for suspension from a helicopter cargo hook, the grapple assembly including a support frame which includes a cargo hook connector, a pair of opposed grapple jaws pivotally connected to the support frame, a hydraulic drive ram connected at opposite ends to each of the pair of grapple jaws, a hydraulic fluid reservoir connected to a pump, the pump and hydraulic fluid reservoir being configured to supply and remove hydraulic fluid from the hydraulic drive ram, a hydraulic controller connected to a wireless signal receiver, the hydraulic controller being configured to receive control signals from the wireless signal receiver and to transmit command signals to the pump, at least one battery configured to supply electrical energy to the hydraulic controller and the pump, wherein the hydraulic fluid reservoir, pump, hydraulic controller and wireless signal receiver and the at least one battery are mounted to and supported by the support frame.

According to a further aspect of the present invention there is provided a grapple assembly substantially as described above which includes a single hydraulic ram pivotally connected between only the grapple jaws so that operation of the hydraulic ram moves both opposed jaws relative to the support frame.

According to a further aspect of the present invention there is provided a grapple assembly substantially as described above which includes a cage housing configured to at least partially enclose the hydraulic controller, wireless signal receiver and battery or batteries.

The present invention provides a grapple assembly which may preferably be used in combination with a helicopter. This grapple assembly may be suspended from the cargo hook of a helicopter, or may be connected to an equivalent dedicated linkage which connects the grapple assembly to a suspension cable engaged with the helicopter. In preferred embodiments the grapple assembly may only require one point of attachment to a helicopter, and may also not require modifications to be made to the helicopter for the grapple assembled to be used effectively.

The grapple assembly includes a support frame which acts as chassis used to mount, support, connect or otherwise suspend the other remaining components of the assembly. In a preferred embodiment the support frame may have a two-part form, defining an upper frame engaged with energy supply and control components integrated into the assembly, and a lower frame engaged with the jaws of the grapple. Preferably the support frame may include a cargo hook connector formed by an aperture defined adjacent to the top of the upper frame when orientated for suspension below a helicopter.

As indicated above, the support frame also includes a cargo hook connector which facilitates the connection of the grapple assembly to one end of a suspension cable connected to a helicopter. This cargo hook may be included through being integrally formed as part of the support frame, or as a further component connected to the support frame. In preferred embodiments the cargo hook connector facilitates the connection of the grapple assembly to one end of a suspension cable providing a single point of connection to a helicopter.

In a preferred embodiment a cargo hook connector may be formed by an eyelet or aperture defined near the top of the frame when orientated for suspension below a helicopter. This eyelet connector may - for example - receive the end of a suspension cable, or maybe engaged with any form of appropriate hook or ll-bolt connection system. Those skilled in the art will appreciate that a cargo hook connector implemented by the invention may have a variety of forms depending on the arrangement of the suspension cable it is to connect to.

The grapple assembly incorporates a pair of opposed grapple jaws which are pivotally connected to the support frame. In operation these jaws can be pivoted relative to the support frame between a closed configuration which grasps a load to be carried by the helicopter, and an open configuration which releases this load.

In preferred embodiments each jaw of the grapple may define or incorporate a plurality of projecting tines which interleave with the tines of the opposite jaw when placed in a closed configuration.

Preferably each jaw includes a tine at each end of the jaw with the pivoting connection made to the support frame located between these tines.

In a further preferred embodiment each jaw may include at least one removable intermediate tine capable of connection and disconnection from the jaw. In various embodiments such removable tines may be connected to a jaw approximately adjacent to the jaw's pivoting connection to the support frame. Those skilled in the art will appreciate that a range of connection systems may be used to connect and disconnect a removable tine to a jaw, such as for example nut and bolt connectors or their equivalents. These removable tines allow the grapple assembly to be reconfigured depending on the load it is primarily used to lift. Three or more tines may be provided on a jaw when small logs or trimmed branches and slash material is to be grasped, while two tines only can be used to reduce the weight of the grapple assembly and lift relatively large logs.

The grapple assembly includes a hydraulic ram connected at opposite ends to each pair of grapple jaws. A hydraulic ram may be extended and retracted from a housing cylinder through the application or withdrawal of pressurised hydraulic fluid to apply a driving force to each jaw.

In preferred embodiments the hydraulic drive ram connections may be made adjacent to each jaw's pivoting connection to the support frame. Furthermore the ends of this hydraulic ram may only be connected to the grapple jaws so that its operation moves both opposed jaws relative to the support frame at the same time. In preferred embodiments the grapple assembly may include a single hydraulic ram only connected to or between each of the two grapple jaws. The use of a single ram can minimise the overall weight of the grapple assembly, improving its load carrying and handling characteristics.

Reference throughout this specification will also be made to the grapple assembly including a single hydraulic ram only. However those skilled in the art should appreciate that in other embodiments two or more rams may be provided for each pair of grapple jaws if desired.

In various preferred embodiments each of the two grapple jaws may both be mounted to the opposite ends of a pair of opposed linkage bars. The two grapple jaws can be pivotally connected to axles sandwiched between the opposite ends of the pair of linkage bars to facilitate movement of both jaws at the same time by operation of the hydraulic ram, preventing lopsided opening and closing movements.

The grapple assembly includes a hydraulic fluid reservoir connected to a pump, with both the reservoir and the pump being mounted to and supported by the support frame. This combination of fluid reservoir and pump are configured to supply and remove hydraulic fluid from the hydraulic drive ram, thereby pivoting the grapple jaws between their open and closed configurations. For example in a preferred embodiment these components may be provided by a hydraulic power pack model HE2000 manufactured by Contentric Rockford, but those skilled in the art will appreciate that other components may also be utilised.

In various embodiments the grapple assembly may include a hydraulic controller connected to a wireless signal receiver with both the controller and receiver being mounted to and supported by the support frame. This hydraulic controller is configured to receive control signals from the wireless signal receiver where these control signals are issued by the pilot of the helicopter using the grapple assembly. The hydraulic controller can then transmit appropriate command signals to the pump to control the supply or removal of pressurised hydraulic fluid to the hydraulic ram. For example in a preferred embodiment these components may be provided by a radio remote control and receiver model 4EM manufactured by Magnetek, but those skilled in the art will appreciate that other components may also be utilised.

However in other embodiments the grapple assembly may not include a wireless signal receiver. In such embodiments the assembly may - for example - include a wired signal receiver which engages with a command signal wire connected to the helicopter used to operate the grapple. This wired signal receiver may therefore be used to transmit control signals issued by the pilot of the helicopter to the hydraulic controller. In a further preferred embodiment existing helicopter control systems used with the operation of monsoon buckets may be used to provide grapple open and close commands to the invention.

In various additional embodiments a relief valve may also be provided with the hydraulic fluid reservoir and the hydraulic ram. This relief valve may be triggered once the ram reaches the end of its normal travel to return hydraulic fluid back to the reservoir. This component can be provided to prevent over pressurization of the hydraulic elements and damage to the invention.

The grapple assembly includes at least one battery mounted to and supported by the support frame. This battery or batteries are configured to supply electrical energy to the hydraulic controller and hydraulic pump referenced above. The combination of battery, hydraulic fluid reservoir, pump and hydraulic controller connected to a wireless signal receiver provides for a self-contained independent energy supply and control system. All the components required to operate the grapple are engaged with the support frame, greatly simplifying the engagement of the grapple assembly with an unmodified helicopter and the use of the assembly in combination with such an unmodified helicopter.

In a further preferred embodiment the terminals of a battery or batteries mounted to the support frame may be removably engaged with a power bus or wiring harness to deliver electrical energy to the pump and hydraulic controller. Preferably the removal connectors used can readily allow a discharge battery to be swapped out for a charged battery wherever the grapple assembly is being used. For example, in various embodiments the invention may provide a removable tray or shelf to support and mount the battery or batteries to the support frame. This feature can allow flat batteries to be disconnected and swapped for charged batteries easily and quickly if required.

In a further preferred embodiment of the invention may also include a battery charging circuit connected to a power bus or wiring harness used to deliver electrical energy to the pump and hydraulic controller. In such embodiments this charging circuit can be used to recharge a battery connected to this wiring harness when an appropriate source of electrical energy is available to the grapple assembly. For example in one particular embodiment two 12V batteries may be provided with serial connections to a 24V battery charging circuit, preferably provided by a helicopter. In a preferred embodiment the grapple assembly may include a cage housing configured to at least partially enclose the hydraulic controller, wireless signal receiver and battery or batteries. In further preferred embodiment the grapple assembly may include a cage housing configured to at least partially enclose the hydraulic pump, reservoir and controller, wireless signal receiver and battery or batteries referenced above. This cage housing protects these relatively delicate energy supply and control components from impacts and damage which can result from the use of the invention in forestry environments. Furthermore the arrangement of the cage housing - whether it be formed from interleaved bars or an array of apertures formed in a plate - allows air to circulate around the protected components, cooling them during use of the invention.

The present invention may provide many potential advantages over the prior art.

The present invention can provide a grapple assembly with a self-contained, self- powered character for use with helicopters and preferably in forestry and logging applications. This grapple assembly may be suspended from a single point only on a helicopter, and not require this helicopter to be specially refitted or modified to use the grapple.

The self-contained compact nature of the invention results in a single localised weight being suspended from a helicopter when a load is lifted. This arrangement will be familiar to many pilots who have previously used cargo hooks for other types of loads, mitigating the need for specialist flight training to be provided to use the invention.

In various embodiments the invention may provide a grapple assembly with a robust and lightweight design, protecting delicate energy supply and control components from impacts and damage when used in forestry applications.

In various additional embodiments the number of tines connected to the jaws of the grapple may be changed, allowing the invention to be reconfigured based on the application it is used in and the loads to be carried.

Brief description of the drawings

Additional and further aspects of the present invention will be apparent to the reader from the following description of embodiments, given in by way of example only, with reference to the accompanying drawings in which: • Figure 1 shows a perspective view of a grapple assembly as provided in accordance with a preferred embodiment,

• Figures 2a, 2b and 2c show end and side views of the grapple assembly of figure 1,

• Figure 3a shows a perspective view of the grapple assembly of figure 1 with the cage housing removed, with figure 3b showing a cross section view of the opposite side of the assembly of figure 1 as shown by figure 3a,

• Figures 4a, 4b show additional end and cross section side views of the grapple assembly of figure 1 with the cage housing removed, and

• Figures 5a, 5b show front and side views of the grapple assembly of figures 1 through 4 when suspended from a helicopter.

Further aspects of the invention will become apparent from the following description of the invention which is given by way of example only of particular embodiments.

Best modes for carrying out the invention

Figure 1 shows a perspective view of a grapple assembly as provided in accordance with a preferred embodiment, while figures 2a, 2b show end and side views of the grapple assembly of figure 1.

The grapple assembly 1 shown in these figures includes a support frame 2 which defines an upper frame 2a and a lower frame 2b. The upper frame 2a is used to mount and support energy supply and control components of the grapple as discussed further with respect to figures 3a, 3b and 4a, 4b.

The upper region and sides of the upper frame are also used to mount a cage housing 3 which serves to protect these energy supply and control components from impacts and damage. As can be seen from figure 1 and 2a-c the cage housing 3 is formed in this embodiment by sheet metal walls formed with regular arrays of holes to allow cooling air to circulate around the energy supply and control components.

The upper frame also defines a cargo hook connector, implemented in this embodiment by eyelet projection 4. This eyelet allows the grapple assembly to be connected to one end of a suspension cable engaged with a helicopter.

The lower frame 2b is pivotally connected to a pair of grapple jaws 5 by way of axle linkage 6 disposed between a pair of opposed linkage bars. This pivoting connection allows the jaws to pivot between a closed configuration as shown by figure 2b, and the open configuration shown by figure 2c. Each jaw 4 defines a set of permanently fixed end tines 7 which interleave with those of the opposite jaw when placed in the closed configuration shown in figure 1. In the embodiment shown each jaw also has a removable intermediate tine 8 capable of connection and disconnection from the jaw using nut and bolt connectors 9. This tine can be added or removed to the grapple on demand depending on the form of the load to be grasped and carried by the grapple assembly.

The grapple assembly 1 includes a hydraulic drive ram 10 connected at its opposite ends to each of the pair of grapple jaws. As shown in detail by the side cross section view of figure 4b a single hydraulic ram only is provided which is pivotally connected between only the grapple jaws and not the lower frame 2b. This connection arrangement ensures that operation of the hydraulic ram moves both opposed jaws relative to the support frame at the same time.

Figures 3a, 3b and figures 4a, 4b show in further detail the energy supply and control components integrated into the grapple assembly and protected by the cage housing. In particular the upper frame is used to mount a battery and electronics housing 11. Also provided is a hydraulic fluid reservoir 12a connected to a pump 12b. The battery and electronics housing locates an array of batteries 13a in addition to a hydraulic controller 13b connected to a wireless signal receiver 13c.

The batteries 13a supply electrical energy to the controller 13b and signal receiver 13c in addition to the pump 12b, allowing wireless control signals to be received from a pilot of the helicopter and for the controller to issue appropriate command signals to the pump based on what the pilot requires. As will be appreciated by those skilled in the art in other embodiments a wired signal receiver may replace the wireless signal receiver, allowing existing helicopter control systems provided for monsoon buckets to be used to control the opening and closing of the grapple.

Figures 5a, 5b show front and side views of the grapple assembly 1 of figures 1 through 4 when suspended from a helicopter 14. These figures illustrate the self- contained, self-powered character of the grapple when use with helicopters. This grapple assembly is suspended from a single point only on the helicopter, and does not require the helicopter to be specially refitted or modified to use the grapple. In various embodiments the grapple can include a wireless signal receiver to allow the helicopter pilot to issue grapple open and close commands and for the grapple to be suspended only by the load cable 15 shown. In other embodiments wired control signal cables may also be provided with the load cable in a similar manner to those provided with helicopter monsoon buckets. As shown by figures 5a, 5b, the self-contained compact nature of the invention results in a single localised weight being suspended from a helicopter when a load is lifted. Pilots who have previously used cargo hooks for other types of loads are familiar with this arrangement, mitigating the need for specialist flight training to be provided to use the invention.

In the preceding description and the following claims the word "comprise" or equivalent variations thereof is used in an inclusive sense to specify the presence of the stated feature or features. This term does not preclude the presence or addition of further features in various embodiments.

It is to be understood that the present invention is not limited to the embodiments described herein and further and additional embodiments within the spirit and scope of the invention will be apparent to the skilled reader from the examples illustrated with reference to the drawings. In particular, the invention may reside in any combination of features described herein, or may reside in alternative embodiments or combinations of these features with known equivalents to given features. Modifications and variations of the example embodiments of the invention discussed above will be apparent to those skilled in the art and may be made without departure of the scope of the invention as defined in the appended claims.