CA2954153A1 - Apparatuses and methods for clearing ground brush and debris at remote target areas - Google Patents

Abstract

An apparatus for clearing vegetation at remote sites. An apparatus has: a helicopter; a cable suspended by the helicopter; and a ground surface mowing device connected to the cable. A
method includes operating a helicopter while suspending a ground surface mowing device by a cable from the helicopter.

Description

APPARATUSES AND METHODS FOR CLEARING GROUND BRUSH AND DEBRIS
AT REMOTE TARGET AREAS
TECHNICAL FIELD
[0001] This document discloses apparatuses and methods for clearing ground brush and debris at remote target areas.
BACKGROUND

[0002] Remote forested sites are cleared manually by workers who are transported to site using ground operated vehicles.
SUMMARY

[0003] An apparatus is disclosed for clearing vegetation at remote sites.

[0004] An apparatus is disclosed comprising: a helicopter; a cable suspended by the helicopter; and a ground surface mowing device connected to the cable.

[0005] A method is disclosed comprising operating a helicopter while suspending a ground surface mowing device by a cable from the helicopter.

[0006] In various embodiments, there may be included any one or more of the following features: The cable connects, via a connector part that secures or forms part of the cable, to a pull bar mounted to the ground surface mowing device. The pull bar extends between a front end and a rear end of the ground surface mowing device. An apex of the pull bar is located partway between the front end and the rear end of the ground surface mowing device. The apex is located in relation to a center of mass balance of the ground surface mowing device such that when the apex is engaged by the connector part and the ground surface mowing device is lifted by the cable through the connector part, the ground surface mowing device is supported in a horizontal orientation. The pull bar comprises a pair of pull bars that extend along respective sides of the ground surface mowing device.
The connector part comprises a cross member that: spans the pair of pull bars; and secures the cable. The cross member is a cross bar that is bent to define an apex to which the cable connects. The pull bar is configured to permit the connector part to slide along the pull bar between a front end lifting position and a rear end lifting position of the pull bar. The ground surface mowing device comprises: a structural frame with ground engaging members; a rotary cutting blade mounted to an underside of the structural frame; and a power assembly for driving the rotary cutting blade. The power assembly comprises a hydraulic motor. A governor for automatic throttle adjustment of the rotary cutting blade based on blade loading. The ground surface mowing device is configured to be operated wirelessly by a remote control device. The ground surface mowing device is suspended by the helicopter over, upon, or adjacent one or more of a remote oil or gas well site, or a remote pipeline. The helicopter is operated to pull the ground surface mowing device along a ground surface to cut vegetation on the ground surface. The helicopter is operated to lift an end of the ground surface mowing device to clear an obstacle on the ground surface. The obstacle comprises a trench, a rock, a mound, or a fallen tree. Clearing one or more of: a helicopter landing area on the ground surface; an area for an oil or gas well; an area for a pipeline; and an area in the path of a forest fire.
Operating further comprises: flying the helicopter to a target area while the ground surface mowing device is suspended from the helicopter; and lowering the ground surface mowing device onto the ground surface at the target area. Operating further comprises: lifting the ground surface mowing device off of the target area; and flying the helicopter away from the target area while the ground surface mowing device is suspended from the helicopter. The pull bar extends from the front end to the rear end of the ground surface mowing device. The pull bar is configured to permit the connector part to slide along the pull bar. The pull bar defines a minor apex, at or near a front end of the pull bar, that is engaged by the connector part when in the front end lifting position. The ground engaging members comprise wheels.
The ground surface mowing device is configured to cut grass and bushes. The ground surface mowing device is configured to cut trees and branches. Clearing an area for one or more of an oil or gas well, or a pipeline. Clearing vegetation in the path of a forest fire, or as part of a forest fire prevention strategy. Controlling operation of the ground surface mowing device wirelessly from the helicopter.

[0007] These and other aspects of the device and method are set out in the claims, which are incorporated here by reference.

BRIEF DESCRIPTION OF THE FIGURES

[0008] Embodiments will now be described with reference to the figures, in which like reference characters denote like elements, by way of example, and in which:

[0009] Fig. 1 is a top plan view of a ground surface mowing device, with pull bars and a cross member shown in dashed lines.

[0010] Fig. 2 is a bottom plan view of the ground surface mowing device of Fig. 1.

[0011] Fig. 3 is a first side elevation view of the ground surface mowing device of Fig. 1 illustrating lifting and pulling modes of operation.

[0012] Fig. 4 is a second side elevation view of the ground surface mowing device of Fig. 1.

[0013] Fig. 5 is an elevation view of a cable connector part formed by a bent cross bar.

[0014] Fig. 6 is an elevation view of a cable connector part formed by a cable cross member.

[0015] Fig. 7 is a side elevation view of a ground surface mowing device suspended from a helicopter via a cable.

[0016] Fig. 7A is a schematic illustrating a method of transporting a ground surface mowing device by helicopter to and from a target site.

[0017] Figs. 8 - 9 are a sequence of side elevation views illustrating a method of operating a helicopter to pull a ground surface mowing device over an obstacle, in this case a fallen tree, to clear vegetation such as grass and bushes.

[0018] Fig. 8A is an exploded view of the area delineated by dashed lines in Fig. 8, illustrating a remote control device for controlling operation of a ground surface mowing device.

[0019] Figs. 10 - 11 are a sequence of side elevation views illustrating a method of operating a helicopter to pull a ground surface mowing device over a trench.
DETAILED DESCRIPTION

[0020] Immaterial modifications may be made to the embodiments described here without departing from what is covered by the claims.

[0021] Forestry mulching machines are used to clear forested areas.
Forestry mulching machines are also referred to as a forestry mulchers, masticators, or brushcutters, Such machines may be used to clear vegetation to form paths and right-of-ways, to clear areas adjacent pipelines, power lines, commercial, residential and industrial buildings, for wildfire prevention and management, vegetation management, invasive species control, wildlife restoration, site preparation and development, cutting and clearing brush, nature and recreational trails, and seismic exploration.

[0022] By processing trees and other vegetation where they stand, mulching machines eliminate many of the steps involved in land clearing such as site prep, cutting, felling, hauling, and site cleanup. This also eliminates the need for support machines such as a bulldozer, excavator, tree shear, wood chippers or grinder, and hauling equipment. Some mulching machines are capable of clearing land of unwanted trees and brush with limited disturbance to soils or desirable vegetation. Mulching the vegetation leaves the soil structure intact. The mulched material can be left on the ground and will act as an erosion barrier while returning nutrients back into the soil through decomposition. Over time, grass will naturally grow through the mulch.

[0023] Forestry mulching machines may have a rotary drum equipped with steel chipper tools or teeth to shred vegetation. They may be manufactured as application-specific tractors and as mulching attachments or heads for existing tracked and rubber-tired forestry tractors, skid steers, or excavators. Heavy duty forestry mulchers may clear up to fifteen acres of vegetation a day depending on terrain, density, and type of material.
Mulching areas with a variety of vegetation and terrain may require multiple types of mulchers, including tracked mulching machines, excavator mulchers, and skid steer tractors equipped with mulching attachments. Even for the largest machines, mulching is only effective when less than 25 tons of vegetation or 100 trees are present per acre. Although mulching is significantly faster and less labor-intensive than land clearing by hand, it requires the site to have road access for fueling and maintenance. Forestry mulchers are relatively large machines, often equal to or larger in size than an automobile, have limited range, and must be transported to site by truck flat bed.

[0024] Forestry mulchers may be used for wildfire prevention and management in various ways. Proactive mulching may be performed to reduce the potential for wildfires by eliminating small leafy plants, fallen or rotten trees, and other fuel sources. If left untreated, these fuel loads increase potential for fire, increase the heat intensity, and serve as fire ladders that enable fire to elevate quickly to the tops of trees which is where a fire can spread most quickly. Mulching can also be used to create a coarse grind finish that can create a more controlled burn. In addition to proactive thinning of vegetation to mitigate fire fuels, forestry mulchers may be used for reactive cutting of lines on active fires or to create firebreaks. Larger forestry mulchers leave minimal cleanup requirements and can help reduce the overall costs of active fire mitigation. After a fire is put out and cleanup efforts are under way, tracked forestry mulching machines, mulching attachments, and an excavator with a mulching attachment can provide a top layer of mulch to prevent soil erosion on slopes and minimize water pollution.

[0025] Remote forested sites, for example remote oil or gas well drilling or production sites, pipelines, and muskegs, may require clearing, which is a process by which vegetation such as trees and bushes are cut down. The clearing of a remote site involves the transport of personnel and manual cutting equipment to and from the site. By conventional methods it may take several days for personnel to travel by land to and from a remote site.
All-terrain vehicles (ATVs) may be used to transport workers to such sites.
However, such vehicles may break down prior to reaching or upon leaving a site, potentially stranding the worker in a remote location. A stranded worker may be at significant risk particularly if such a worker is injured. While at the site, a worker may clear vegetation manually via powered or unpowered cutting tools.

[0026] Referring to Fig. 7 an apparatus 10 is disclosed comprising a helicopter 12, a cable 14, and a ground surface mowing device 16. The cable 14 may be suspended by helicopter 12. The mowing device 16 may be connected to cable 14. Helicopter 12 may be operated while suspending ground surface mowing device 16 by cable 14 from helicopter 12.
Referring to Fig. 7A, the helicopter may transport the mowing device 16 between a base, such as a hangar 103, a remote target area 105, and back to the hangar 103.
Referring to Figs. 8-9, while at the area 105, the helicopter 12 may be operated to pull the ground surface mowing device 16 along a ground surface 102 to cut vegetation on the ground surface 102.

[0027] Referring to Figs. 1-2, ground surface mowing device 16 may be structured to cut, for example mulch, vegetation. Ground surface mowing device 16 may comprise a structural frame 92 with ground engaging members, for example comprising wheels 24. In some cases ground surface mowing device 16 has tracks, skis, wheels or other suitable ground engaging members. Referring to Fig. 2, mowing device 16 may have a rotary cutting blade 78, which may be mounted, for example via a spindle (not shown), to an underside 92A of the structural frame 92. Referring to Fig. 1, mowing device 16 may have a power assembly, for example comprising a hydraulic motor 64, for driving the rotary cutting blade 78 (Fig. 2). Steering arm linkages 60 may be connected one or more of the ground engaging members. Referring to Figs. 2 and 3, ground surface mowing device 16 may have a mowing deck 94, for example that houses rotary cutting blade 78. Referring to Fig. 2, deck 94 may define an opening 94A, to expose the ground surface to the action of the cutting blade 78, and a throat area 94B within which the cutting blade 78 or the drive axle of same may be partially inset. Referring to Fig. 8, ground surface mowing device 16 may be configured to cut one or more of grass 104, bushes 118, trees such as upright trees or fallen trees, tree stumps, branches, brush, and / or other vegetation. The mowing device 16 may incorporate a guard, for example a steel grate or side guard 18, in order to protect various components of the mowing device 16 from contact with flying debris such as sticks and rocks ejected by the mowing device 16.

[0028] Referring to Fig. 2, rotary cutting blade 78 may have a structure suitable for cutting vegetation. Ground surface mowing device 16 may comprise a plurality of blades 78.
Each rotary cutting blade 78 may define a leading cutting edge 78B. Each blade 78 may have a trailing wing, for example a trailing upturned wing 78C that is shaped to move towards the deck 94 with increasing distance from the leading edge 78B. The tips 78A of the rotary cutting blades 78 may collectively define a circular cutting area 80 during rotation. As blades 78 rotate, the trailing upturned wings 78C may create an updraft that suspends clippings within a cutting zone of mowing deck 94. Vegetation cut by rotary blade 78 may recirculate within throat area 94B of mowing deck 94, for example to be re-cut or mulched by rotary blade 78. Blades 78 may extend laterally off of a drive shaft or spindle 79, which is connected to be driven by the power assembly, for example the hydraulic motor 64 (Fig. 1).

[0029] Referring to Fig. 1, ground surface mowing device 16 may have a suitable power assembly, which may include an engine 54. Engine 54 may be of suitable construction, for example a two-cycle or two-stroke engine, which is a type of internal combustion engine which completes a power cycle with two strokes (up and down movements) of a piston of the engine during one crankshaft revolution. An example of a suitable two-stroke is the KAWASAKITM 440. In a two-stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust (or scavenging) functions occurring at the same time.
Two-stroke engines often have a high power-to-weight ratio, with power being available in a narrow range of rotational speeds referred to as the power band. Two-stroke engines may have a reduced number of moving parts relative to four-stroke engines, and may therefore be more compact and lighter, although an engine other than a two-stroke engine may be used. Engine 54 may run on suitable fuel, for example gasoline, supplied from a fuel source such as a fuel tank 30. Replacement fuel (not shown) may be transported to site by the helicopter 12. A
tachometer 74 may be connected to engine 54, for example to measure revolutions per minute (RPM) or speed of engine 54. Ground surface mowing device 16 may have one or more other suitable features, such as a temperature switch 70, a temperature probe, and an RPM gauge 36, for example to display the RPM of engine 54. An exhaust part 56 may be provided for example for guiding reaction exhaust gases away from combustion inside engine 54. Exhaust part 56 may have one or more exhaust pipes and / or a muffler (not shown).

[0030] Referring to Fig. 1, engine 54 may be started via a suitable mechanism, such as an engine starter 72. Engine starter 72 may comprise one or more of an electric motor, pneumatic motor, hydraulic motor, an internal-combustion engine, or other device suitable for rotating engine 54 so as to initiate engine 54 operation. A solenoid 32 may be connected to engine starter 72. When an electric current is sent through solenoid 32, solenoid 32 may then relay an electric current to engine starter 72, which in turn sets engine 54 in motion.
Starter solenoid 32 may receive power from a battery 28.

[0031] Referring to Fig. 1, ground surface mowing device 16 may incorporate a carburetor 46 for mixing air and fuel for combustion may be present.
Carburetor 46 may be connected to engine 54 to atomize fuel within an air stream and to permit transfer of the resulting air-fuel gas mixture to engine 54 for combustion within engine 54.
Carburetor 46 may be connected to fuel tank 30 to receive fuel, for example for mixing with air, from fuel tank 30.

[0032] Referring to Fig. 1, a suitable structure may be used to ignite the air-fuel mixture within the engine 54. For example, a capacitor discharge ignition (CDI) coil 52 and spark plug cables 50 may be used. A CDI or thyristor ignition is a type of automotive electronic ignition system which is widely used in outboard motors, motorcycles, lawn mowers, chainsaws, small engines, turbine-powered aircraft, and some cars. A
CDI uses capacitor discharge current to the coil to fire the spark plugs. In a CDI
system, a charging circuit charges a high voltage capacitor, and at the instant of ignition the system stops charging the capacitor, allowing the capacitor to discharge its output to the ignition coil before reaching the spark plug. A CDI module may have a small transformer, a charging circuit, a triggering circuit, and a main capacitor. Other systems may be used to ignite the air-fuel mixture within the engine 54. Spark plug cables 50 may deliver electric current from the CDI to a combustion chamber to ignite an air-fuel mixture within the combustion chamber via respective spark plugs 50A. Spark plugs 50A may have a suitable structure such as a metal threaded shell, electrically isolated from a central electrode by a porcelain insulator. The central electrode may protrude through the porcelain insulator into the combustion chamber, forming one or more spark gaps (not shown) between the inner end of the central electrode.

[0033] Referring to Fig. 1, the power unit may incorporate a hydraulic system for driving rotary cutting blades 78. A suitable hydraulic system may incorporate one or more of a hydraulic fluid cooling system, such as cooling radiator 20, a hydraulic cooler fan 62, and hydraulic filter 22, and a hydraulic fluid power circuit, such as including a hydraulic fluid reservoir 26, a hydraulic pump 34, hydraulic motor 64, hydraulic fluid supply and return lines 63, and a hydraulic solenoid 76. Hydraulic filter 22 may be configured to keep hydraulic fluid in the hydraulic system free of contamination. Contamination may arise from use and wear of parts of the hydraulic system, poor plumbing, and contamination brought in with new fluid or new parts. Hydraulic cooling radiator 20 may be configured to cool hydraulic fluid to prevent overheating during use. Hydraulic motor 64 may be a suitable motor such as a power take-off or belt driven motor. Hydraulic motor 64 may be connected to and / or driven by hydraulic pump 34 via suitable lines 63, such as hoses, tubing, or conduits that circulate pressurized fluid to and from hydraulic motor 64.
Hydraulic motor 64 may be connected, for example via a drive shaft or spindle 79 (Fig. 2) of ground surface mowing device 16, for example for driving rotation of rotary cutting blade 78.

[0034] Referring to Fig. 1, ground surface mowing device 16 may be controlled via one or more of manual control, automatic control, and remote control. Ground surface mowing device 16 may have one or more manual controls, which may be operated directly by a user adjacent the mowing device 16. For example one or more buttons, switches, levers, or other control devices may be provided for operating ground surface mowing device 16.
Ground surface mowing device 16 may have one or more of a start button 44, a button for engaging governor 48, a button for engaging the hydraulic system, a shutdown button or kill switch 40, and an on / off switch 42. Various controls and parts may be connected to a fuse panel 38 that is mounted to ground surface mowing device 16 to prevent damage from power surges during use. A wiring harness 68 may be provided.

[0035] Referring to Figs. 1-2, one or more automatic controls may be provided. As shown, ground surface mowing device 16 may comprise a governor 48 for automatic throttle adjustment of rotary cutting blade 78 (Fig. 2) based on blade loading.
Governor 48 may measure and regulate the speed of engine 54, for example using signals from tachometer 74.
Governor 48 may be programmed to maintain the number of revolutions per minute (RPM) of engine 54 within a predetermined operating range, such that if the RPM dip or spike below or above the selected range, the engine operation is adjusted to achieve operation within the selected range. The range may be selected by a user to achieve a desired cutting performance. Different ranges may be set, for example high RPM low torque for thin grass, and low RPM high torque for dense grass, bushes, and in some cases trees. A
controller (not shown), such as a programmable logic control may be incorporated to automate and control engine and motor function.

[0036] Referring to Figs. 8 and 8A, ground surface mowing device 16 may be configured to be operated via remote control, for example via a suitable wireless control mechanism. Ground surface mowing device 16 may be wirelessly or remotely started, controlled, and operated by a remote control device 88 (Fig. 8A), for example from helicopter 12 or another suitable location. Remote control device 88 may have one or more of an engine start button 88A, a remote button 88B for engaging governor 48, a remote button 88C for engaging and disengaging the hydraulic system (initiating mowing action), a remote shutdown button 88D, and other suitable buttons for remotely controlling ground surface mowing device 16. Control signals, and in some cases return status signals, may be sent between ground surface mowing device 16 and remote control device 88 (Fig. 8A) via a suitable wireless medium such as Wi-Fi, radio waves, 3G or 4G technology, cellular networks, BLUETOOTHTm, or another suitable mechanism. Remote control device 88 may communicate with ground surface mowing device 16 via a wireless control box 66 (Fig. 1).
Suitable components may be provided to receive, process, and send signals, such as transceiver and receiver equipment.

[0037] Referring to Figs. 8 and 8A, remote control may reduce the manpower or logistical demands of operating the system. For example, remote control may permit helicopter 12 to be operated by a single person. Remote control device 88 may permit a single person to fly helicopter 12 to a ground surface 102, start and stop ground surface mowing device 16, operate the device 16 to clear vegetation on site, lift ground surface mowing device 16 from ground surface 102, and return to a base or starting location, without leaving the cockpit or landing the helicopter 12. In some cases remote control may incorporate steering and/or driving the mowing device 16, for example using controls and a ground engaging member drive unit, respectively, located on the mowing device 16. In some cases a second, third, or more individual(s) may be present in the helicopter 12 for assisting in operation of the device 16.

[0038] Referring to Fig. 7, cable 14 may engage helicopter 12 in a manner suitable for lifting and pulling ground surface mowing device 16. Cable 14 may be connected or secured to skids/skis 90F or another suitable part of helicopter 12. A
suitable connection mechanism may be used to secure the cable 14 to the helicopter 12, for example a carabiner 106 (Fig. 5), a hook 107 (Fig. 6), a pulley, and a winch. In some cases the cable 14 is retractable and extendable, for example if a winch (not shown) is mounted to the helicopter 12. A control device (not shown) may be used to permit the pilot or passenger to extend and retract the cable 14, for example to adjust the length of the cable 14 during operation to suit a particular target area. Adjustments in cable length may be needed particularly if the heights of trees adjacent the target area are higher or shorter than expected. The cable may also have a fixed length, for example as shown where the cable 14 is secured to the skids or skis 90F.
The cable 14 may be relatively inflexible (limited stretch, limited elasticity) for more predictable force transfer through the cable 14.

[0039] Referring to Fig. 7, cable 14 may have characteristics suitable for lifting and pulling ground surface mowing device 16. The length of cable 14 may be chosen based on tree height. The length of cable 14 may be at least thirty percent longer than the height of the tallest tree or an average height of the trees on a ground surface to be cleared, for example to accommodate situations in which cable 14 is at non-zero angle, relative to vertical while pulling the ground surface mowing device 16. Cable 14 may form a tow line.
Cable 14 may comprise a plurality of cables, for example attached at different connection points to ground surface mowing device 16. The plurality of cables may provide additional control, for example the ability to lift one corner of ground surface mowing device 16 to a greater height relative to the other corners of ground surface mowing device 16.

[0040] Referring to Fig. 7, one or both of cable 14 or helicopter 12 may comprise a cable release mechanism 99 for releasing cable 14 from helicopter 12 when a tension in cable 14 exceeds a predetermined threshold. The cable release mechanism may have a pressure release hook. In some cases, the cable release mechanism has a manual or remote controlled release mechanism.

[0041] Referring to Fig. 3, ground surface mowing device 16 may be structured to be lifted and / or pulled by the helicopter 12. Cable 14 may connect, via a connector part 82 that secures or forms part of the cable 14, to a structural member such as a pull bar 84 mounted to the ground surface mowing device 16. The pull bar 84 may extend or run between a front end 16A and a rear end 16B of the ground surface mowing device 16, and in some cases from the front end 16A to the rear end 16B. Referring to Fig. 1, pull bar 84 may comprise a plurality, such as a pair of pull bars 84A and 84B, for example parallel bars, that are each associated with or extend along respective sides 16C and 16D of the ground surface mowing device 16. The pair of pull bars 84A and 84B may collectively form a structural frame or part of a structural frame, for example a lift or pull frame 58.

[0042] Referring to Figs. 1 and 3, connector part 82 may be configured to facilitate pulling and / or lifting of ground surface mowing device 16. Referring to Fig.
5, the connector part 82 may comprise a cross member, such as a cross bar 86, that spans the pull bars 84A and 84B (Fig. 1), and secures the cable 14. Referring to Fig. 5, a cross bar 86 may be bent to define an apex 86A, for example an apex centrally located between respective pull bar connection points, for example rings 112, of the cross bar 86. Cable 14 may connect to bar 86 at apex 86A. Other connector parts 82 may be used, for example a connector part 82 may comprise part of the cable 14 itself, for example (not shown) a loop and /
or a knot formed at an end of cable 14.

[0043] Referring to Fig. 3, pull bar 84 may be configured to permit connector part 82 to slide along pull bar 84. Sliding may be permitted between a front end 84C
and a rear end 84D of pull bar 84, for further example between a front end lifting position and a rear end lifting position of pull bar 84 as illustrated by the dashed lines to the right and left in Fig. 3 showing respective lifting directions 96 and 98. Referring to Fig. 5, connector part 82 may have arms 82A and 82B configured or connected to engage or slide along respective bars of the pair of pull bars 84A and 84B (Fig. 1). Referring to Fig. 5, connector part 82 may form a ring 112, for example having an inner aperture diameter that is larger than a diameter of pull bar 84 (Fig. 1). Referring to Fig. 3, the connector part 82, for example the rings 112, may be structured to permit pivoting of connector part 82 relative to pull bar 84, for example by dimensioning the inner aperture diameter of each ring 112 sufficiently wide to permit pivoting. Connector part 82 may form a split ring (not shown). Referring to Fig. 6, other suitable connector parts 82 may be used, for example a connector part 82 that forms a sling 110. A sling connector part 82 may incorporate one or more hooks 108, and may itself connect by hook to cable 14. Suitable connectors other than hooks may be used.

[0044] Referring to Fig. 7, pull bar 84 may be structured to permit cable 14 to lift the mowing device 16 in a balanced fashion, to facilitate lifting via and / or suspension of device 16 from helicopter 12. Referring to Fig. 3, an apex 84E of pull bar 84 may be defined partway, for example centrally, between front end 16A and rear end 16B of ground surface mowing device 16. Apex 84E may be located in relation to a center of mass balance 77 of ground surface mowing device 16 such that when apex 84E is engaged by connector part 82 and ground surface mowing device 16 is lifted by cable 14 through connector part 82, ground surface mowing device 16 may be supported in a balanced, for example horizontal, orientation. When connector part 82 engages or is lodged in apex 84E, connector part 82 and / or an end of cable 14 may overly the center of gravity of ground surface mowing device 16.
A horizontal orientation may refer to the fact that a plane defined by the ground engaging elements, such as wheels 24, is horizontal. Horizontality includes nominal deviations from horizontal, such as deviations of up to thirty degrees. A mass-balanced lift may be achieved by locating apex 84E above center of mass balance 77 or above an axis passing through center of mass balance 77 if plural pull bars are used on either side of center of mass balance 77 as shown.

[0045] Referring to Figs. 8, 8A, 9, 10, and 11, pull bar 84 may have a structure suitable for clearing obstacles or obstructions on the ground surface 102 during operation.
Helicopter 12 may be operated to lift an end, for example front end 16A or back end 16B, of the ground surface mowing device 16 to clear an obstacle, for example a trench such as a beaver trench 120 (Figs. 10-11), a rock, a mound, or a log 114 (Figs. 8-9), on ground surface 102 or in the path of ground surface mowing device 16. Using helicopter 12 in such a fashion may increase the mobility of the mowing device 16 relative to a comparable mowing device driven over the ground surface 102 without the aid of cable 14 and helicopter 12. For example, where an independent mowing device 16 may get stuck or restricted by such an obstacle, the cable 14 and helicopter 12 are able to lift an end, and potentially the entire structure, of mowing device 16 to clear the obstacle. Referring to Fig. 3, pull bar 84 may define an apex 100, such as a minor apex, at or near front end 84C of the pull bar 84 as illustrated by the dashed lines 141, that is engaged by connector part 82 when in the front end lifting position. In some cases, pull bar 84 defines a rear apex, at or near rear end 84D of pull bar 84, that is engaged by connector part 82 when in the rear end lifting position. An apex is a major apex if the apex forms the highest point in a structure when the device 16 is resting on a horizontal ground surface 102, and an apex is a minor apex if other apexes, such as apex 84E, defined by the structure are higher than the minor apex.

[0046] Referring to Fig. 7, a helicopter 12 may have a rotor system 90 that generates lift. Rotor system 90 may comprise a mast 90A, hub 90B, and rotor blades 90C.
Mast 90A
may be a cylindrical metal shaft that extends upwards from a transmission (not shown). Two, three, four or more rotor blades 90C may be mounted to mast 90A via hub 90B at the top of mast 90A. Rotor system 90 may include a vertically mounted assembly, such as a tail rotor 143 that provides horizontal thrust to counteract torque from the main rotor blades 90C.
Main rotor systems are classified according to how the rotor blades are attached and move relative to the hub. There are three basic types: hingeless, fully articulated, and teetering. Lift and thrust supplied by rotors allow helicopters to take off and land vertically, to hover, and to fly forward, backward, and in lateral directions. Such attributes allow helicopters to be used in congested or isolated forested areas where fixed-wing aircraft and many forms of vertical takeoff and landing (VTOL) aircraft cannot perform.

[0047] Referring to Fig. 7, control input adjustments and corrections by a pilot may be required to keep helicopter 12 in position. Helicopter 12, when hovering, may generate its own gust of air that acts against a main body of helicopter 12, for example fuselage 90D, and flight control surfaces. To tilt forward and back (pitch) or sideways (roll), control inputs may be manipulated to alter the angle of attack of the main rotor blades cyclically during rotation, creating differing amounts of lift (force) at different points in the cycle.
To increase or decrease overall lift, control inputs may be manipulated to alter the angle of attack for all blades collectively by equal amounts at the same time, resulting in ascent, descent, acceleration and deceleration. Turning may be achieved by adjusting the relative rotational speeds between the tail rotor 143 and the main rotor blades 90C.

[0048] Referring to Fig. 7, helicopter 12 may have any one or more of a cyclic input, a collective input, an anti-torque input or pedal, or other suitable flight control input (not shown). A cyclic input may be used to eliminate drift in the horizontal plane, for example to control forward and back as well as right and left motion. A collective input may be used to maintain altitude. An anti-torque input may be used to control nose direction or heading. An adjustment of any one control input may require an adjustment of the other inputs, creating a cycle of constant correction. As a helicopter moves from hover to forward flight it enters a state called translational lift which provides extra lift without increasing power. This state may occur when the airspeed reaches approximately 16-24 knots, and may be necessary for a helicopter to obtain flight.

[0049] Referring to Fig. 7, in forward flight a helicopter's flight controls may behave more like those of a fixed-wing aircraft. Displacing the cyclic input forward may cause a nose 90E of helicopter 12 to pitch down, with a resultant increase in airspeed and loss of altitude. Displacing the cyclic aft may cause nose 90E to pitch up, slowing helicopter 12 and causing it to climb. Increasing collective input while maintaining a constant airspeed may induce a climb while decreasing collective input may cause a descent.
Coordinating these two inputs, for example down collective plus aft cyclic or up collective plus forward cyclic, may result in airspeed changes while maintaining a constant altitude.

[0050] 1-2 paras. from start to end. attach to helicopter, fly to site, lower, turn it on, mow, pull around, lift up over obstacles, maybe clear a landing pad, land, get out do manual cutting or cutting with mower, turn off mower, take off, fly home to airport.
refer to all method figs.

[0051] Referring to Fig. 7, a method comprises operating a helicopter while suspending a ground surface mowing device 16 by a cable 14 from the helicopter 12.
Helicopter 12 may be operated to transport ground surface mowing device 16 to a target area, for example to be cleared, via a suitable method. Mowing device 16 may first be secured to helicopter 12, for example by securing a first end 14A of cable 14 to helicopter 12, securing a second end 14B of cable 14 to ground surface mowing device 16.
Referring to Figs. 7 and 7A, ground surface mowing device 16 may be lifted from a starting location, for example an airport or a hangar 103, via helicopter 12 and cable 14, and helicopter 12 flown to a target area 105 while ground surface mowing device 16 is suspended from helicopter 12.
Referring to Figs. 7A and 8, ground surface mowing device 16 may be lowered onto a ground surface 102 at the target area. Ground surface mowing device 16 may be initiated, turned on, or otherwise switched into a mowing mode, for example via one or more of manual controls, automatic controls, and remote controls. Ground surface mowing device 16 may be suspended over, upon, or adjacent one or more of a remote oil or gas well site, or a remote pipeline.

[0052] Referring to Figs. 8-11, helicopter 12 may be operated while suspending ground surface mowing device 16 by cable 14 from helicopter 12, for example to cut vegetation on a ground surface, via a suitable method. Referring to Fig. 8, helicopter 12 may be operated to pull ground surface mowing device 16 along ground surface 102, for example in a forward direction 116 via cable 14 or in a backward direction via cable 14', to cut vegetation on the ground surface 102. Referring to Figs. 8, 8A, and 10, helicopter 12 may be operated to lift an end, for example front end 16A or back end 16B, of the ground surface mowing device 16 to clear an obstacle, for example a trench such as a beaver trench 120 (Fig. 10), a rock, a mound, a log 114, or a fallen tree, on ground surface 102 or in the path of ground surface mowing device 16. Referring to Fig. 9, a ground surface mowing device 16' may be used to cut vegetation, such as grass 104 and/or bushes 118. Referring to Figs. 7-11, apparatus 10 may be used for clearing a helicopter landing area on a ground surface 102 such as a meadow, for example to permit landing to unload workers with handheld tools such as bushwhacking devices to perform further clearing of the site. Referring to Fig. 9, apparatus may be used for clearing an area for one or more of an oil or gas well 145, or a pipeline 147, or for other suitable uses such as clearing vegetation in the path of a forest fire, or as part of a forest fire prevention strategy.

[0053] Referring to Figs. 7 and 7A, helicopter 12 may be operated to transport or return ground surface mowing device 16 to the starting location or another suitable return point, via a suitable method. The mowing device 16 may be shut down, or otherwise switched out of a mowing mode. Operating helicopter may comprise lifting ground surface mowing device 16 off of the target area, and flying helicopter 12 away from the target area while ground surface mowing device 16 is suspended from helicopter 12. In some cases the mowing device 16 is disconnected from the cable 14 and stored in the helicopter 12 itself for one or more of the trip from starting point to target area or target area to return point.

[0054] A drum blade or other suitable cutter apparatus may be used in place of or in conjunction with rotary blade 78. In some cases, helicopter 12 is an unmanned apparatus, for example a drone. Ground surface mowing device 16 may be a rotary lawn mower, a mulching device, a foliage mower, a forestry mower, or a rotary reducing machine. Cable 14 may be a suitable length such as ninety or more feet in length, although shorter lengths may be used. Ground surface 102 may comprise an uneven surface unsuitable for use with a common residential push lawnmower. The mower may incorporate a drive for propelling the mower, for example in a forward or backward motion. The mower may incorporate a steering device for steering the motor. The drive and steering device may be controlled by manual or automatic control, and in some cases remote control. The mowing device 16 may be a passive system that can only be moved along the ground surface 102 by manipulation via cable 14. The device 16 may be used on well leases, pipeline rights of way, muskeg, power line sites, sites with buildings, and other suitable remote locations, prior to or after installation of infrastructure such as wells, drilling rigs, pipelines or others. The device 16 may also be used on commercial, residential, or rural sites. The mowing device 16 may be configured to be operated while being ridden by a user. The mowing device 16 may have plural modes such as a) a helicopter operated mode where the device 16 is towed along surface 102 by helicopter 12, and b) a manual operation mode where the mowing device 16 is operated by a user without the assistance of helicopter 12.

[0055] In the claims, the word "comprising" is used in its inclusive sense and does not exclude other elements being present. The indefinite articles "a" and "an"
before a claim feature do not exclude more than one of the feature being present. Each one of the individual features described here may be used in one or more embodiments and is not, by virtue only of being described here, to be construed as essential to all embodiments as defined by the claims.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus comprising:
a helicopter;
a cable suspended by the helicopter; and a ground surface mowing device connected to the cable.
2. The apparatus of claim 1 in which the cable connects, via a connector part that secures or forms part of the cable, to a pull bar mounted to the ground surface mowing device.
3. The apparatus of claim 2 in which the pull bar extends between a front end and a rear end of the ground surface mowing device.
4. The apparatus of claim 3 in which an apex of the pull bar is located partway between the front end and the rear end of the ground surface mowing device.
5. The apparatus of claim 4 in which the apex is located in relation to a center of mass balance of the ground surface mowing device such that when the apex is engaged by the connector part and the ground surface mowing device is lifted by the cable through the connector part, the ground surface mowing device is supported in a horizontal orientation.
6. The apparatus of any one of claim 2 - 5 in which the pull bar comprises a pair of pull bars that extend along respective sides of the ground surface mowing device.
7. The apparatus of claim 6 in which the connector part comprises a cross member that:
spans the pair of pull bars; and secures the cable.

8. The apparatus of claim 7 in which the cross member is a cross bar that is bent to define an apex to which the cable connects.
9. The apparatus of any one of claim 2 -8 in which the pull bar is configured to permit the connector part to slide along the pull bar between a front end lifting position and a rear end lifting position of the pull bar.
10. The apparatus of any one of claim 1 - 9 in which the ground surface mowing device comprises:
a structural frame with ground engaging members;
a rotary cutting blade mounted to an underside of the structural frame; and a power assembly for driving the rotary cutting blade.
11. The apparatus of claim 10 in which the power assembly comprises a hydraulic motor.
12. The apparatus of any one of claim 10 - 11 further comprising a governor for automatic throttle adjustment of the rotary cutting blade based on blade loading.
13. The apparatus of any one of claim 10 - 12 in which the ground surface mowing device is configured to be operated wirelessly by a remote control device.
14. The apparatus of any one of claim 1 - 13 in which the ground surface mowing device is suspended by the helicopter over, upon, or adjacent one or more of a remote oil or gas well site, or a remote pipeline.
15. A method comprising operating a helicopter while suspending a ground surface mowing device by a cable from the helicopter.
16. The method of claim 15 in which the helicopter is operated to pull the ground surface mowing device along a ground surface to cut vegetation on the ground surface.

17. The method of claim 16 in which the helicopter is operated to lift an end of the ground surface mowing device to clear an obstacle on the ground surface.
18. The method of claim 17 in which the obstacle comprises a trench, a rock, a mound, or a fallen tree.
19. The method of any one of claim 16 - 18 further comprising clearing one or more of:
a helicopter landing area on the ground surface;
an area for an oil or gas well;
an area for a pipeline; and an area in the path of a forest fire.
20. The method of any one of claim 15 - 19 in which operating further comprises:
flying the helicopter to a target area while the ground surface mowing device is suspended from the helicopter; and lowering the ground surface mowing device onto the ground surface at the target area.
22. The method of any one of claim 20 - 21 in which operating further comprises:
lifting the ground surface mowing device off of the target area; and flying the helicopter away from the target area while the ground surface mowing device is suspended from the helicopter.