GB2534220A

GB2534220A - Tree-cutting head

Info

Publication number: GB2534220A
Application number: GB1500842.8A
Authority: GB
Inventors: Page Andrew
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-01-19
Filing date: 2015-01-19
Publication date: 2016-07-20
Anticipated expiration: 2035-01-19
Also published as: GB2534220B; GB201500842D0

Abstract

A tree-cutting head 2 comprising a chainsaw assembly comprising a main body 6, a guide bar 22 attached to the main body, a sprocket (25; Fig.6) and a chain wound around the guide bar and sprocket. The guide bar defines a cutting plane. The tree-cutting head also includes a clamping assembly 8 for removably attaching the tree-cutting head to a tree. The clamping assembly is pivotally attached to the main body such that pivoting the main body with respect to the clamping arrangement causes the guide bar to pivot in the cutting plane. The clamping assembly preferably comprises pivotally attached first and second arms, wherein the main body is pivotally attached to the first arm. The tree-cutting head optionally comprises a spring arrangement for biasing the gripping arms in an open position. The tree-cutting head preferably comprises a gimbal joint.

Description

Tree-cutting head

Field of the Invention

The present invention relates to a tree-cutting head.

Background

Trees are often found in urban and rural environments. Effective tree management is employed to ensure that trees remain healthy and do not present hazards to people, buildings and infrastructure, and also to ensure that roads and footpaths remain io passable.

Tree management often involves trimming higher branches or trunks of trees. An arborist (commonly known as a "tree surgeon") may often employ mechanical lifts or climb up trees in order to access the higher parts of trees. However, it is desirable to /5 avoid working at elevated heights for safety reasons and/or to reduce the complexity of common tree trimming operations.

A pole saw, comprising a chainsaw or other blade mounted to one end of a long pole, tube or boom, can be used to trim trees without the need to work at elevated heights.

For example, US 4 916 818 A describes a handheld device which includes a telescopic tube-shaft extending between an engine at ground level and a gear box attached to a chain saw guide bar. The chain saw is adjustable so that the cutter chain can cut into the upper surface of a tree branch or into a side surface of the branch.

DE 44 17 885 Al describes a hand held saw having a petrol or electric motor with a handle/throttle which is attached to a guide tube. The guide tube has a handgrip and spring, which allows a branch etc. to be gripped by gripper arms when relaxed. An inner tube with a universal joint shaft drives a saw blade which saws the branch off.

US 2012/0037275 Al describes a tree processing head configured for mounting to the end of a carrier boom attached to a tractor or similar vehicle for processing a tree element. The tree processing head includes a body, a scissor assembly mounted to the body and a chainsaw assembly also mounted to the body. The scissor and chainsaw assemblies are selectively usable individually or cooperatively to process the tree dement.

It is often necessary to trim vertical or near vertical trunks or branches. Hand operated pole saws, however, are incapable or poorly suited to making horizontal or near horizontal cuts.

Summary

The present invention seeks to provide an improved tree-cutting head and a tree-cutting implement which includes the tree-cutting head.

According to a first aspect of the invention there is provided a tree-cutting head comprising a chainsaw assembly comprising a main body, a guide bar fixedly attached to the main body, a chainsaw sprocket and a chain wound around the guide bar and sprocket, the guide bar defining a cutting plane, and a clamping assembly for removably attaching the tree-cutting head to a tree, the clamping assembly pivotally attached to the main body such that pivoting the main body with respect to the clamping arrangement causes the guide bar to pivot in the cutting plane.

Thus, a tree may be cut/trimmed by securing the tree-cutting head to the tree using the clamping assembly and causing the main body of the tree-cutting head to pivot relative to the clamping assembly to move the chainsaw bar through the cutting plane to cut the tree. The tree-cutting head can be simpler and safer to operate because an operator does not need to operate any controls whilst cutting.

The clamping assembly may comprise a first arm having first and second ends, and a second arm having first and second ends, wherein the main body is pivotally attached -0or to the first arm at any point between and including the first and second ends and the second end of the first arm is pivotally attached to the second end of the second arm.

The main body may be pivotable with respect to the clamping assembly from a first position towards a second position for cutting the tree and the tree-cutting head may further comprise a first spring arrangement arranged to bias the clamping assembly towards the first position away from the second position.

Thus, the tree-cutting head may be easily and reliable positioned to clamp a tree.

The main body may be pivotally attached to the first arm at a point proximate to the first end. -3 -

The first and second arms may have an open position for receiving a tree, and the tree cutting head may further comprise a second spring arrangement arranged to bias the first and second arms towards the open position, and a closing arrangement configured to cause the first and second arms to pivot against the biasing of the second spring arrangement.

The closing arrangement may comprise a cable attached to the second arm between the first and second ends, and an opening attached to the first arm between the first and /o second ends, wherein the cable passes through the opening and is configured such that in response to the cable being pulled through the opening the second arm is caused to pivotably move relative to the first arm against the biasing of the second spring arrangement.

The main body may further comprises a seat which is configured to couple to a tubular pole which is orientated along an axis substantially perpendicular to the cutting plane. The seat may comprise a tubular coupling portion which coaxially receives a pole. The seat may comprise a tubular coupling portion which is received into a pole.

The tree cutting head may further comprising a gimbal joint comprising a gimbal ring, a first fitting pivotally connected to the gimbal ring and attached to the main body offset from the point of attachment of the clamping assembly, and a second fitting pivotally connected to the gimbal ring.

or Thus, the main body can be moved by simply rotating, or rotating and translating, the second fitting of the gimbal ring. Additionally, the gimbal joint provides flexibility and can allow an operator to choose a safe position for cutting, away from the tree and/or avoiding ground-based obstacles.

The tree-cutting head may further comprise a universal joint in rotatable communication with the chainsaw sprocket and which passes through the gimbal ring.

This can help to reduce the weight of the tree-cutting head, since the motor can be provided separately to the tree-cutting head. -4 -

The tree-cutting head may further comprise a third spring arrangement arranged to bias the gimbal joint towards an initial position. The initial position of the gimbal joint may be coaxial alignment.

According to a second aspect of the invention there is provided a tree-cutting implement comprising a tree-cutting head according to the first aspect, a motor in rotatable communication with the chainsaw sprocket, and a tubular pole having first and second ends, wherein the first end of the pole is coupled to the tree-cutting head.

The tree-cutting implement may further comprise a pole axle disposed within the pole, wherein a first end of the pole axle is in rotatable communication with the chainsaw sprocket and a second end of the pole axle is in rotatable communication with the motor.

The tubular pole may comprise one or more tubular segments configured to be connectable end-to-end.

Thus, the length of the tubular pole may be readily adaptable to trim tree parts and branches at a range of heights above the ground.

This can make the tree-cutting implement easier to manoeuvre by reducing the weight -0or of the tree-cutting head, since the motor can be provided at the operator end of the pole.

The pole axle may comprise one or more pole axle segments disposed within corresponding one or more tubular segments and wherein the one or more pole axle segments may be configured to be connectable end-to-end. The pole axle segments may be configured to be connected to each other by universal joints.

The tree cutting implement may further comprise a ratchet lever assembly positioned proximate to the second end of the pole and configured to tension the cable. The tree-35 cutting implement may further comprise a lever fixedly attached to the pole proximate to the second end and extending substantially perpendicular to the tubular pole. -5 -

When the tree-cutting head does not include a gimbal joint, the first end of the tubular pole maybe coupled to the main body such that the tubular pole is substantially perpendicular to the cutting plane. The tubular pole maybe attached to the main body 5 at a point offset from the point at which the clamping assembly is pivotally attached.

When the tree-cutting head does include a gimbal joint, the first end of the tubular pole may be coupled to the second fitting of the gimbal joint. The first end of the pole axle may be coupled to the universal joint which passes through the gimbal ring. When the /o gimbal joint is in the initial position the tubular pole may make an angle to the perpendicular of the cutting plane of up to 45 degrees, up to 3o degrees, up to to degrees or o degrees.

According to a third aspect of the invention there is provided a method of cutting /5 through a part of a tree using a tree-cutting implement according to the second aspect, the method comprising clamping the tree-cutting head to the part of a tree, and rotating the pole and/or moving the second end of the pole in an arc. -6 -

Brief Description of the Drawings

Certain embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 illustrates an operator using a first tree-cutting implement including a first tree-cutting head to trim a portion of a tree; Figure 2 is a perspective view of the tree-cutting head shown in Figure 1; Figure 3 is a plan view of the tree-cutting head shown in Figure 1; Figure 4 is a side view of the tree-cutting head shown in Figure 1; Figure 5 is perspective view of a chassis comprising part of the tree-cutting head shown /.0 in Figure 1; Figure 6 is an exploded perspective view of the first tree cutting head shown in Figure 1; Figure 7 is a partial cross-sectional view of a main body of the tree-cutting head shown in Figure 1; Figure 8 is a perspective view of a universal joint and part of a gimbal joint comprised in the tree cutting head shown in Figure 1; Figure 9 shows partial cross sectional and perspective views of the universal joint included in the tree-cutting head shown in Figure 1; Figure 10 shows a clamp closing arrangement of the tree-cutting head shown in Figure 1; Figure 11 shows a ratchet lever for operating the clamp closing arrangement shown in Figure 10; Figure 12 shows a schematic geometry of operating the tree-cutting implement shown in Figure 1; Figures 13a to 13d show the operation of the tree-cutting implement shown in Figure 1 to sever a trimmed portion of a tree; Figure 14 illustrates an operator using a second or third tree-cutting implement including a second or third tree-cutting head to trim a portion of a tree; Figure 15 is a side view of a second tree-cutting head; Figure 16 shows a schematic geometry of operating a second tree-cutting implement including a second tree-cutting head shown in Figure 14; Figure 17 is an exploded perspective view of a third tree-cutting head; Figure 18 is a plan view of the tree-cutting head shown in Figure 17; Figure 19 is a side view of the tree-cutting head shown in Figure 17; Figure 20 shows a partial cross sectional view of the main body of the tree-cutting head along the line labelled "A" in Figure 18; and -7 -Figure 21 shows a schematic geometry of operating a third tree-cutting implement including a tree-cutting head shown in Figure 17.

Detailed Description of Certain Embodiments

In the following description, like parts are denoted by like reference numerals.

Referring to Figure 1, a first tree-cutting implement 1 is shown.

The first tree-cutting implement 1 includes a first example of a tree-cutting head 2 /o removably coupled to a distal end of a tubular pole 3. An operator may use the first tree-cutting implement i to cut a portion 4 of a tree 5 to be removed. The trimmed portion 4 may be a branch of the tree 5 or the trunk of the tree 5. The trimmed portion 4 may be oriented vertically or at an angle within 3o degrees of vertical. The end of the tubular pole 3 which is removably coupled to the first tree-cutting head 2 is referred to herein as the "coupled end" and the end of the tubular pole 3 grasped by the operator is referred to herein as the "operator end".

The first tree-cutting head 1 includes a first example of a main body 6 to which a chainsaw blade 7 is fixedly attached and a first example of a clamping assembly 8 is pivotably attached.

As will be explained in more detail hereinafter, to cut a tree 5, an operator clamps the first tree-cutting head 2 to the tree 5 using the first clamping assembly 8. With the chainsaw blade 7 powered, the operator pivots the first main body 6 though an arc about the first clamping assembly 8 by rotating the operator end of the pole 3, or by a combination of rotating and translating the operator end of the pole 3. This causes the first main body 6 to pivot through an arc about the first clamping assembly 8, so that the chainsaw blade 7 cuts into the tree 5. The operator continues to pivot the first main body 6 about the first clamping assembly 8 until the chainsaw blade 7 has cut through the trimmed portion 4 of the tree 5.

The first tree-cutting head 2 includes a gimbal joint 9 which allows the angle between the tubular pole 3 and the cutting plane 10 defined by the chainsaw blade 7 to be varied. The pole 3 and the cutting plane 10 are initially perpendicular, and the gimbal joint 9 allows the angle between them to be varied by up to 45 degrees in any direction. This allows the operator to make a horizontal or near horizontal cut whilst angling the pole 3 -8 -so that the operator is not located beneath the trimmed portion 4. The angle between the pole 3 and the cutting plane 10 can be varied continuously as the first main body 6 is pivoted through an arc about the first clamping assembly 8.

Referring also to Figure 2, a gimbal spring arrangement 11 biases the gimbal joint 9 to an initial position (herein referred to as the "gimbal initial position") in which the pole 3 is perpendicular to the cutting plane 10. The gimbal spring arrangement 11 is configured to provide biasing forces just sufficient to overcome the weight of the first tree-cutting head 2 so that the gimbal joint 9 remains in the gimbal initial position until intentionally displaced by the operator. The gimbal spring arrangement if does not provide biasing forces sufficient to prevent or impair the operator from varying the angle between the pole 3 and the cutting plane 10 in use.

The gimbal joint 9 and the gimbal spring arrangement 11 may be configured such that the gimbal joint 9 is biased to an initial position in which the pole 3 is not perpendicular to the cutting plane 10. For example, the first tree-cutting implement 1 may be configured so that the angle made between the pole 3 and the perpendicular to the cutting plane 10 in the gimbal initial position is up to 45 degrees, up to 30 degrees or up to 10 degrees. The gimbal joint 9 and the gimbal spring arrangement fi may be configured to allow the operator to adjust the initial position before use, for example, by adjusting the tensions of springs included in the gimbal spring arrangement 11.

First tree-cutting head 2 Referring to Figures 2 to 4, the first tree-cutting head 2 will now be described in more 25 detail.

The first main body 6 includes a chassis 12 having a lower surface 13 and an upper surface 14. The gimbal joint 9 includes a first fitting 15 which is integrally formed with the chassis 12 and which depends downwardly from the lower surface 13 of the chassis 12, and a second fitting 16 which is configured to removably couple to the coupled end of the pole 3. The first fitting 15 and the second fitting 16 are coupled together by a two-axis gimbal ring 17. The chassis 12, the first and second fittings 15, 16, and the tubular pole 3 are preferably made from aluminium. However, other lightweight structural materials may be used such as magnesium alloy, or structural composite materials such as glass fibre or carbon fibre reinforced composites. One or more parts can be formed from other materials. The two-axis gimbal ring 17 is preferably made -9 -from steel. However, other hard-wearing materials suitable for providing moving mechanism parts may be used The first fitting 15 has a central axis 18 (herein also referred to as the "drive shaft axis") which is perpendicular to the cutting plane 10. The second fitting has a central axis 19 (herein also referred to as the "pole axis"). The gimbal spring arrangement 11 comprises first and second helical springs zo, 21 connected between the first and second fittings 15, 16 of the gimbal joint 9. The helical springs zo, 21 are made of steel, or other materials with suitable toughness and elastic properties, and are configured to provide just sufficient restoring forces to overcome the weight of the first tree-cutting head and bias the gimbal joint 9 to the gimbal initial position in which the drive shaft axis 18 and the pole axis 19 coincide coaxially. The gimbal initial position need not be coaxial alignment. Other arrangements are possible such that the drive shaft axis 18 and pole axis 19 make an angle of, for example, up to 45 degrees, up to 3o degrees or up to 10 degrees.

However, the gimbal spring arrangement n need not be first and second helical springs. The gimbal spring arrangement 11 may comprise alternative spring arrangements such as, for example, torsion springs integrally included in the couplings between the first and second fittings 15, 16 and the two-axis gimbal ring 17.

The chainsaw blade 7 comprises a chainsaw chain (not shown) wrapped around a first example of a chainsaw guide bar 22 which defines the cutting plane 10 and which is made from steel, or from similar hard-wearing materials suitable for providing moving mechanism parts. The first chainsaw guide bar 22 is fixedly attached to the chassis 12 proximate to an edge 23 of the chassis 12, and the long axis of the first chainsaw guide bar 22 extends away from the chassis 12 along a chainsaw axis 24. The chainsaw chain (not shown) wraps around and is driven by a chainsaw sprocket 25 (Figures 6 & 7), which is fixedly attached to a sprocket axle 26 rotatably mounted to the chassis 12 about a sprocket axis 27. The sprocket axis 27 is perpendicular to the cutting plane 110.

The sprocket axle 26 receives driving torque from a drive shaft axle and gear members described in detail hereinafter. Alternatively, the sprocket axle 26 may be directly driven by an electric, petrol driven, pneumatic or hydraulic motor fixedly mounted to, or integrated into, the first main body 6.

-10 -The first clamping assembly 8 includes a first arm member 28 having a first end portion 29 and a second end portion 30, and a second arm member 31 having a first end portion 32 and a second end portion 33. The first and second arm members 28, 31 are preferably made from aluminium. However, other lightweight structural materials may be used such as magnesium alloy, or structural composite materials such as glass fibre or carbon fibre reinforced composites. One or more parts can be formed from other materials. The first and second arm members 28, 31 are hollow with generally square cross sections and extend in a long direction from the respective first end portions 29, 32 to the respective second end portions 30, 33.

Referring in particular to Figure 3, the first and second arm members 28, 31 are curved along the long direction such that a tangent 34 to the respective first end portion 29, 32 makes an angle 36 with a tangent 35 to the respective second end portion 30, 33. In this example, the angle 36 is about 3o degrees. However, larger or smaller angles 36 may be used depending on the maximum girth of the trimmed portion 4 which the first tree-cutting head 2 is intended to sever. The first and second arm members 28, 31 need not be curved, and may comprise two or more straight sections joined to each other at an angle. The first and second arm members 28, 31 may be solid instead of hollow, and may have non-square or variable cross sections.

The first clamping assembly 8 is pivotably mounted to the first main body 6 by a clamping assembly pivot joint 37. The clamping assembly pivot joint 37 connects the lower surface 13 of the chassis to a first protruding member 38 removably attached to the first arm member 28. In this example, the first protruding member 38 is attached proximate to the first end portion 29 using a nut and bolt arrangement. However, other methods of removable attachment may be used, such as, for example, a clipping or clamping arrangement. The operator may re-position the first protruding member 38 to be attached at different points along the length of the first arm member 28 and including the first and second ends 29, 30. This provides additional flexibility when clamping parts of the tree 5 which are in confined and/or awkward positions. When the first protruding member 38 is not required to be movable with respect to the first arm member 28, the first protruding member may be integrally formed with the first arm member 28, or may be welded or riveted to the first arm member 28.

The clamping assembly pivot joint allows the chassis 12 and the first arm member 28 to be pivoted about a clamping assembly pivot axis 39 which is perpendicular to the cutting plane 10. The long direction of the first arm member 28 lies parallel to the cutting plane 10 and the first arm member 28 curves away from the chassis 12. The clamping assembly pivot joint 37 is positioned proximate to an edge 23 of the chassis 12. However, the clamping assembly pivot joint 37 may be located at any point on the chassis 12 such that pivoting the first main body 6 about the clamping assembly pivot axis 39 will cause the first chainsaw guide bar 22 to move through an arc which covers at least a portion of the first clamping assembly 8.

The clamping assembly pivot joint 37 integrally includes a clamping assembly spring to arrangement (not shown) comprising a torsion spring (not shown) made of steel or other materials with suitable toughness and elastic properties.

Referring in particular to Figure 3, the clamping assembly spring arrangement is configured to bias the clamping assembly pivot joint 37 to an initial position (herein referred to as the "clamping assembly initial position") in which a leading edge 41 of the first chainsaw guide bar 22 overlies an outside face 42 of the first arm member 28 but does not extend past an inside face 43 of the first arm member 28. The chassis 12 can be pivoted relative to the first arm member 28 against the biasing of the clamping assembly spring arrangement by rotating, or by rotating and translating, the operator end of the pole 3 removably coupled to the second fitting 16 of the gimbal joint 9 along the pole axis 19. The clamping assembly pivot joint 37 is configured so that the chassis 12 can be pivoted about the clamping assembly pivot axis 39 sufficiently to move the first chainsaw guide bar through an arc spanning the first clamping assembly 8.

-0or Different clamping assembly initial positions may be used provided that the chainsaw bar 22 is initially positioned so it does not interfere with the first clamping assembly 8 clamping a tree 5. The clamping assembly spring arrangement need not be a torsion spring, for example, the clamping assembly spring arrangement may be provided by one or more helical springs connected between the chassis 12 and the first arm member 28.

A clamping member pivot joint 44 connects the second end portion 3o of the first arm member 28 to the second end portion 33 of the second arm member 31. The clamping member pivot joint 44 allows pivoting about a clamping member axis 45 which is perpendicular to the cutting plane 10. The second arm member 31 is mounted beneath the first arm member 28, with the long direction parallel to the cutting plane 10 and -12 -curving towards the first arm member 28. The clamping member pivot joint 44 integrally includes a damping member spring arrangement (not shown) comprising a torsion spring (not shown) made of steel or other materials with suitable toughness and elastic properties. The second arm member 31 need not be mounted below the first arm member 28. Other arrangements are possible, such as, for example, mounting the second arm member 31 above the first arm member 28, mounting first and second arm members 28, 31 to be substantially coplanar or mounting the first and second arm members 28, 31 to each other using a piano hinge arrangement.

/o Referring in particular to Figure 3, the clamping member spring arrangement 46 is configured to bias the first arm member 28 and the second arm member 31 such that an initial angle 47 is made between the respective second end portions 30, 33 (herein referred to as the "open clamp position"). The initial angle 47 is approximately 90 degrees. However, the initial angle 47 may be different dependent on the curvature of the first and second arm members 28, 31 and the maximum girth of the tree portion 4 which it is intended for the first tree-cutting head 2 to sever. The first and second arm members 28, 31 are pivoted towards each other in order to clamp a tree 5, against the biasing of the clamping member spring arrangement, using a clamp closing arrangement 48 described in detail hereinafter. The clamping member spring arrangement need not be a torsion spring, for example, the clamping member spring arrangement may be provided by one or more helical springs connected between the first and second arm members 28, 31.

The first end portions 29, 32 of the first and second arm members 28, 31 of the first clamping assembly 8 include inwardly facing triangular teeth 49 to improve the gripping of a tree 5 by the first clamping assembly 8. However, other arrangements can be used. For example, the teeth could be different shapes such as spikes or cones, or the inwardly facing teeth may be replaced by deformable pads made of a resilient material such as natural, vulcanised or silicone rubber.

ChaSSiS 12 Referring also to Figure 5, the chassis 12 will now be described in more detail.

The first main body 6 includes a chassis 12 comprising a chassis case 50 and a chassis 35 lid 51. The chassis case 50 includes a base portion 52 having an upper surface 53 and a lower surface 54 which provides the lower surface 13 of the chassis 12. The chassis 12 -13 -has a perimeter formed by a first circular arc portion 55 centred on the sprocket axis 27, a second circular arc portion 56 centred on the clamping assembly pivot axis 39 and two straight tangent portions 57 which tangentially connect the first and second circular arc portions 55, 56. The first circular arc portion 55 has a relatively larger radius than the second circular arc portion 56 and the sprocket axis 27 and clamping assembly pivot axis 39 are parallel and separated by a distance 58 along the chainsaw axis 24. The distance 58 is greater than the radius of the first circular arc portion 55.

A perimeter wall 59 and internal gear train wall 6o extend perpendicularly from the upper surface 53 of the base portion 52 to form a gear train compartment 61, and an internal shaft wall 62 encloses a circular internal shaft 63. Several additional internal walls 64 enclose internal spaces 65 which may contain an oil reservoir (not shown) and a pump (not shown) for lubricating the chainsaw chain (not shown). The internal spaces 65 may also contain a chain tensioning mechanism (not shown) for tensioning the chainsaw chain (not shown). The perimeter wall 59 and internal walls 6o, 62, 64 form a chassis case upper surface 66. The internal gear train wall 6o spans between the tangent portions 57. A circular sprocket axle receiving aperture 67 is formed through the base portion 52 coaxially with the sprocket axis 27 and a circular drive shaft receiving aperture 68 is formed through the base portion 52 coaxially with the drive shaft axis 18. The sprocket axle receiving aperture 67 and drive shaft receiving aperture 68 do not intersect each other and are wholly contained within the gear train compartment 61. In this example, the sprocket axis 27, drive shaft axis 18 and clamping assembly pivot axis 39 are coplanar. A circular clamping assembly pivot member receiving aperture 69 is formed through the base portion 52 coaxially with the clamping assembly pivot axis 39 and coincident with the circular internal shaft 63.

The first fitting 15 of the gimbal joint 9 depends downwardly from the lower surface 54 of the base portion 52 of the chassis 12. The first fitting 15 comprises first and second right rectangular cuboids 70, 71, each having a long axis in a direction perpendicular to the drive shaft axis 18 and the chainsaw axis 24. First and second T-shaped members 72, 73 depend downwardly from the first and second cuboids 70, 71 and each T-shaped member 72, 73 comprises first and second portions, i.e. bar portion 74 and upright portion 75. The bar portion 74 of each of the T-shaped members 72, 73 extends parallel to the long axis of the respective cuboids 70, 71. The upright portion 75 of each of the T-shaped members 72, 73 extends perpendicularly away from the lower surface 54 of the base portion 52 of the chassis case 50 and includes a respective circular aperture 76, 77 having an axis parallel to the chainsaw axis 24. The circular apertures 76, 77 receive the two-axis gimbal ring 17 of the gimbal joint 9.

The chassis lid 51 has an upper surface 78 which provides the upper surface 14 of the chassis 12, and a lower surface 79 which is configured to mate with the upper surface 66 of the chassis case 50. A circular sprocket axle receiving aperture 8o and a circular drive shaft receiving aperture 81 are formed through the chassis lid 51 and are configured to align coaxially with the respective apertures 67, 68 in the chassis case 50 when the chassis 12 is assembled. A circular clamping assembly member receiving aperture 82 is formed through the chassis lid 51 and configured to align coaxially with the clamping assembly pivot member receiving aperture 69 and the circular internal shaft 63 in the chassis case 5o when the chassis 12 is assembled. The circular clamping assembly member receiving aperture 82 formed through the chassis lid 51 has a relatively smaller diameter than the clamping assembly pivot member receiving aperture 69 and the circular internal shaft 63 formed thorough the chassis case 50. A rectangular protrusion 83 extends perpendicularly upwards from the upper surface 78 of the chassis lid 51 and is configured to be received by a corresponding alignment slot 84 formed through the first chainsaw guide bar 22. An elliptical protrusion 85 extends perpendicularly upwards from the upper surface 78 of the chassis lid 51 and surrounds the sprocket axle and drive shaft receiving apertures 8o, 81, so that the chainsaw sprocket 25 supports the chainsaw chain (not shown) clear of the upper surface 78 of the chassis lid 51.

The upper surface 78 of the chassis lid 51 and the chainsaw sprocket 25 may be further 25 covered by a chassis cover (not shown) to prevent external objects, such as twigs from the tree 5, debris etc., from interfering with the chainsaw sprocket 25 driving the chainsaw chain.

The chassis 12 is formed from rigid and tough materials. In this example, the chassis 12 is made from aluminium. However, other lightweight structural materials may be used such as magnesium alloy, or structural composite materials such as glass fibre or carbon fibre reinforced composites. Other suitable metals can be used, such as, for example, steel or titanium. The chassis 12 comprises a chassis case so and a chassis lid 51. However, the chassis 12 may be formed from more or fewer parts depending on the materials and fabrication methods chosen.

-15 -Sprocket axle assembly Referring also to Figures 6 to 9, the first tree-cutting head 2 will now be described in greater detail.

A sprocket axle assembly includes the chainsaw sprocket 25, a first sprocket axle bearing 86 including through-hole 87, a sprocket gear member 88 including through-hole 89, a cylindrical sprocket axle member 90 substantially comprising a first portion 91, a second portion 92 and a widened portion 93, and a second sprocket axle bearing 94 including a through-hole 95. The chainsaw sprocket 25 includes a through hole 96. The first and second sprocket axle bearings 86, 94, the sprocket axle member 90, the sprocket gear member 88 and the chainsaw sprocket 25 are preferably made from steel. However, other hard-wearing materials suitable for providing moving mechanism parts may be used. One or more parts can be formed from other materials.

When the first tree-cutting head 2 is assembled, the components of the sprocket axle assembly are assembled coaxially with the sprocket axis 27. in this example, the first and second sprocket axle bearings 86, 94, and other bearings mentioned hereinafter, are rolling element bearings comprising ball bearings. The bearings 86, 94 may freely rotate with respect the inner surfaces of the respective through-holes 87, 95. However, other types of bearing may be used such as, for example, plain bearings such as bushings or magnetic bearings.

The second sprocket axle bearing 94 has a circular outer perimeter and is fixedly received by the circular sprocket axle receiving aperture 67 formed through the base portion 52 of the chassis case 5o. The second portion 92 of the sprocket axle member 90 is rotatably received by the through-hole 95 of the second sprocket axle bearing 94. The first portion 91 of the sprocket axle member 90 is long enough to protrude through the chassis lid 51 by an amount at least equal to the thickness of the chainsaw sprocket 25. The first portion 91 of the sprocket axle member 90 provides the sprocket axle 26 for attachment of the chainsaw sprocket 25. The through-hole 89 of the sprocket gear member 88 has a diameter equal to the widened portion 93 of the sprocket axle member 90 and the sprocket gear member 88 is fixedly attached to the widened portion 93. The sprocket gear member 88 is contained in the gear train compartment 61 when the chassis 12 is assembled. The first sprocket axle bearing 86 has a circular outer perimeter and is fixedly received by the circular sprocket axle receiving aperture 8o formed through the chassis lid 51. When the chassis lid 51 is assembled to the chassis case 50, the first portion 91 of the sprocket axle member 90 is rotatably received through the through-hole 87 of the first sprocket axle bearing 86 and protrudes above the chassis lid 51 by an amount at least equal to the thickness of the chainsaw sprocket 25. The through-hole 96 of the chainsaw sprocket 25 is equal in diameter to the first portion 91 of the sprocket axle member 90, and the chainsaw sprocket 25 is fixedly attached to the portion of the sprocket axle member 90 which protrudes through the first sprocket axle bearing 86.

Drive shaft axle assembly lo A drive shaft axle assembly includes a first drive shaft bearing 97 having a through-hole 98, a drive shaft gear member 99 having a through-hole 100, a second drive shaft bearing 101 having a through-hole 102, and a drive shaft axle member 103, all preferably made from steel. However, other hard-wearing materials suitable for providing moving mechanism parts may be used. One or more parts can be formed from other materials. The drive shaft axle member 103 substantially comprises a cylindrical shaft portion 104 extending between a first end 105 and an annular ring 106 protruding radially from the shaft portion 104, and a cylindrical universal joint coupling portion 107 extending from the annular ring 106 to a second end 108. The universal joint coupling portion 107 includes a pair of cylindrical protrusions 109 extending perpendicularly from the central axis of the drive shaft member axle member 103. The cylindrical protrusions 109 are located proximate to the second end 108 and extend from opposite sides of the universal joint coupling portion 107 so that the pair of cylindrical protrusions 109 are coaxial.

When the first tree-cutting head 2 is assembled, the components of the drive shaft axle assembly are assembled coaxially with the drive shaft axis 18. The second drive shaft bearing 101 has a circular perimeter and is fixedly received by the drive shaft receiving aperture 68 formed through the base portion 52 of the chassis case 5o. The shaft portion 104 of the drive shaft axle member 103 is rotatably received through the through-hole 102 of the second drive shaft bearing member 101 such that the protruding annular ring 105 abuts the second drive shaft bearing member 101. The shaft portion 104 of the drive shaft axle member 103 is received through the through-hole 100 of the drive shaft gear member 99 and the drive shaft gear member 99 is attached to the shaft portion 104. The drive shaft gear member 99 is contained in the gear train compartment 61 when the chassis 12 is assembled and meshes with the sprocket axle gear member 88 to form a reduction gear train. The first drive shaft -17 -bearing 97 has a circular perimeter and is fixedly received by the drive shaft receiving aperture 81 formed through the chassis lid 51. The through-hole 98 of the first drive shaft bearing 97 rotatably receives the first end 105 of the drive shaft axle member 103.

The sprocket axle gear member 88 and the drive shaft gear member 99 are spur gears. However, alternative types of gears can be used such as, for example, helical gears. The first tree-cutting head 2 need not employ a reduction gear train. Other arrangements are possible such as, for example, the sprocket axle member 90 may receive driving torque from the drive shaft axle member 103 using a belt, or using a sprocket and chain arrangement. The separate sprocket axle member 90 may be omitted and the chainsaw sprocket 25 directly attached to the drive shaft axle member.

Two-axis gimbal ring 17 The two-axis gimbal ring 17 includes a tubular section no including four through holes in formed around the perimeter of the tubular section 110 at ninety degree intervals.

Each of the four through-holes in fixedly receives a cylindrical gimbal ring protrusion member 112 such that the gimbal ring protrusion members 112 extend perpendicularly away from the central axis of the gimbal ring 17 at ninety degree intervals. A pair of the gimbal ring protrusion members 112 located on opposite sides of the gimbal ring 17 are rotatably received by the circular apertures 76, 77 formed through the T-shaped members 72, 73 of the first fitting 15 (see also Figure 5). In this way, the two-axis gimbal ring 17 is mounted to the chassis case 50 such that the universal joint coupling portion 107 of the drive shaft axle member 103 lies inside the tubular section 110 of the two-axis gimbal ring 17. -0or

Tubular pole coupling assembly A tubular pole coupling assembly includes the second fitting 16 of the gimbal joint 9 and also a pole axle bearing 113 including a through-hole 114 and a cylindrically symmetric pole axle coupling member 115 both preferably made from steel. However, other hard-wearing materials suitable for providing moving mechanism parts may be used. One or more parts can be formed from other materials.

When the first tree-cutting head 2 is assembled, the components of the drive shaft axle assembly are assembled coaxially with the pole axis 19. The pole axle coupling member 115 has a first end 116 and a second end 117, and substantially comprises a cylindrical shaft portion 118 extending to the first end 116, and a cylindrical tube portion 119 -18 -having a greater diameter than the shaft portion 118 and extending to the second end 117. A pair of rectangular slots 120 are formed on opposite sides of the tube portion 119 with the slots 120 running parallel to the central axis of the pole axle coupling member 115. The first end 116 of the pole axle coupling member 115 is configured to be removably coupled to a pole axle member (not shown) which runs through the centre of the tubular pole 3 and transmits torque from a motor (not shown) located proximate to the operator pole end of the pole 3. The pole axle member is preferably made from steel. However, other hard-wearing materials suitable for providing moving mechanism parts may be used. The second fitting 16 of the gimbal joint 9 substantially comprises a tubular portion 121 having a lower opening 122 and an tipper opening 123, and a pair of projections 124 extending parallel to the central axis of the tubular portion 121 from opposite sides of the upper opening 123. The end of each projection 124 includes a circular aperture 125 which runs perpendicular to the central axis of the tubular portion 123. The circular apertures 125 on opposed projections 124 are coaxial.

The lower opening 122 of the second fitting 16 is configured to receive and removably couple to the coupled end of the pole 3.

The pole axle bearing 113 is fixedly received into the upper opening 123 of the tubular portion 121 of the second fitting 16. Shaft portion n8 of the pole axle coupling member 115 is rotatably received through the through-hole 114 of the pole axle bearing 113. The through holes 125 formed through the opposed projections 124 of the second fitting 16 rotatably receive the remaining pair of cylindrical gimbal ring protrusion members 112 extending from the two-axis gimbal ring 17 such that the cylindrical tube portion 119 of the pole axle coupling member 115 lies through the gimbal ring 17, and the pair of slots 120 formed in the cylindrical tube portion 119 of the pole axle coupling member 115 slidably receive the pair of cylindrical protrusions 109 extending from the universal joint coupling portion 107 of the drive shaft axle member 103.

In this way, the gimbal joint 9 is completed and a universal joint 127 is formed. The universal joint 127 passes through the gimbal ring 17 or the gimbal joint 9 and couples the drive shaft axle member 103 and the pole axle coupling member n5. The gimbal joint 9 allows the angle between the tubular pole 3 reversibly coupled to the second fitting 16 and the cutting place 10 to be varied. The universal joint 127 passing through the gimbal joint 9 allows the drive shaft axle member 103 to receive driving torque from the pole axle member as the orientation of the drive shaft axis 18 and the pole axis 19 is altered.

First chainsaw guide bar 22 The first chainsaw guide bar 22 includes a rectangular slot 84 and a through hole 128. The first chainsaw guide bar is mounted to the first main body 6 by receiving the rectangular protrusion 83 of the chassis lid 51 through the rectangular slot 84 of the first chainsaw guide bar 22. When the first chainsaw guide bar 22 is mounted to the first main body 6, the through-hole 128 of the first chainsaw guide bar 22 is coaxial and /0 coextensive with the circular clamping assembly member receiving aperture 82 formed through the chassis lid 51.

First clamping assembly 8 The first arm member 28 of the first clamping assembly 8 is mounted to the first main 15 body 6 using a clamping assembly pivot member 129 preferably made from steel. However, other hard-wearing materials suitable for providing moving mechanism parts may be used.

When the first tree-cutting head 2 is assembled, the clamping assembly member 129 is assembled coaxially with the clamping assembly axis 39. Clamping assembly pivot member 129 substantially comprises a first cylindrical shaft portion 130 and a second cylindrical shaft portion 131 coaxial with the first shaft portion 13o. A lip 132 is formed at the joint between the first and second shaft portions 13o, 131 of the clamping assembly pivot member 129. The first cylindrical shaft portion 130 of the clamping assembly pivot member 129 has the same diameter as the through hole 128 in the first chainsaw guide bar 22 and the clamping assembly member receiving aperture 82 formed through the chassis lid 51. The second cylindrical shaft portion 131 of the clamping assembly pivot member 129 has the same diameter as the clamping assembly pivot member receiving aperture 69 and the circular internal shaft 63 formed through the chassis case 5o.

The damping assembly pivot member 129 is received through the clamping assembly pivot member receiving aperture 69 and the circular internal shaft 63 formed through the chassis case 50 such that the lip 132 abuts the lower surface 79 of the chassis lid 51 surrounding the clamping assembly member receiving aperture 82. The first portion 130 of the damping assembly member 129 is received through the clamping assembly member receiving aperture 82 formed through the chassis lid 51 and the through hole 128 formed through first chainsaw guide bar member 22. The first portion 130 of the clamping assembly member 129 is threaded and is fixedly attached to the first main body 6 and the first chainsaw guide bar 22 using a nut or nuts (not shown). This also secures the first chainsaw guide bar 22 to the first main body 6, with the rectangular protrusion 83 and the rectangular slot 84 preventing the first chainsaw guide bar 22 from rotating. The clamping assembly member 129 and nut(s) may also secure one end of the chassis lid 51 to the chassis case 50. The clamping assembly member 129 need not be attached to the first main body 6 and the first chainsaw guide bar 22 using a threaded first portion 130. Other attachment methods are possible such as, for example, welding.

The second portion 131 of the clamping assembly member 129 protrudes from the lower surface 54 of the chassis case 50. The first protruding member 38 formed integrally with the first arm member 28 includes a through-hole 133 formed perpendicularly to the long direction of the first arm member 28. The protruding section of the second portion 131 of the clamping assembly member 129 is rotatably received through the through-hole 133 in the first protruding member 38 of the first arm member 28. In this way, the clamping assembly pivot joint 37 is completed. As hereinbefore described, in this example, the clamping assembly pivot joint 37 includes a clamping assembly spring arrangement (not shown) which biases the first main body 6 and first arm member 28 to the clamping assembly initial position.

The first clamping assembly 8 comprises the first and second arm members 28, 31, and -0or a clamping member pivot axle 134 preferably made from steel. However, other hard-wearing materials suitable for providing moving mechanism parts may be used. The first clamping assembly 8 also includes a clamp closing arrangement 48 described in detail hereinafter.

The first arm member 28 includes a through-hole 135 formed perpendicularly to the long direction of the first arm member 28 and proximate to the second end portion 30. The second arm member includes a through-hole 136 formed perpendicularly to the long direction of the second arm member 31 and proximate to the second end portion 33. The first and second arm members 28, 31 are assembled by rotatably receiving the clamping member pivot axle 134 through the respective through-holes 135, 136. In this way, the clamping member pivot joint 44 is completed. As hereinbefore described, in -21 -this example, the clamping member pivot joint 37 includes a damping member spring arrangement (not shown) which biases the first arm member 28 and the second arm member 31 to the open damp position. When the first tree-cutting head 2 is assembled, the clamping member pivot joint 44 is coaxial with the clamping member pivot axis 45.

Clamp closing arrangement 48 Referring also to Figure 10, a clamp closing arrangement 48 which is operable to cause the first and second arm members 28, 31 to dose for damping a tree 5 will now be /o described in more detail.

The closing arrangement 48 comprises a cable 137 attached inside the cross section of the second arm member 31 by a pin 138 at a position on the second arm member 31 offset from the clamping member pivot axle 134. The cable 137 made from twisted steel fibres. However, similar materials which are suitable for providing a flexible tension cable may be used. The pin 138 is preferably made from steel. However, other hard-wearing materials suitable for providing moving mechanism parts may be used. The pin 138 may be fixedly attached to the second arm member 31 or the pin 138 may be free to rotate.

An inside face 139 of the second arm member 31 is the face which is opposed by the inside face 43 of the first arm member 28. The cable 137 leaves the inside face 139 of the second arm member 31 through a slot 140 and the cable 137 is received through a cable receiving member 141 into a cable sheath 142 which is a reinforced plastic tube.

However, similar flexible tube arrangements may be used, such as, for example, a segmented metal tube configured to allow the segments to flex. The cable 137 and cable sheath 142 may comprise a Bowden cable. The cable receiving member 141 is preferably made from steel. However, other hard-wearing materials suitable for providing moving mechanism parts may be used. The cable receiving member 141 is either fixedly or rotatably attached to the first arm member 28 at a point on the first arm member 28 offset from the clamping member pivot axle 134. The cable 137 can move slidably in and out of the cable receiving member 141 and cable sheath 142. When the cable 137 is tensioned so that a portion of the cable 137 in the gap between first and second arm members 28, 31 slides into the cable sheath 142, the first and second arm members 28, 31 are pivoted towards each other against the biasing force provided by the damping member spring arrangement 46.

Referring also to Figure 11, a ratchet arrangement for causing the clamp dosing arrangement 48 to pivot the first and second arm members 28, 31 towards each other will now be described.

The ratchet arrangement provided towards the operator end of the tubular pole 3. The cable 137 is guided along the length of the tubular pole 3 by the cable sheath 142. Proximate to the operator end of the pole 3, the cable sheath 142 is secured to the pole 3 at a cable sheath fixing point (not shown) such that the cable 137 can move slidably in and out of the end of the cable sheath 142. A substantially planar ratchet plate 143 is fixedly attached to the tubular pole 3 such that the ratchet plate 143 is extensive in directions parallel and perpendicular to the pole axis 19. An edge of the ratchet plate opposite to the incident direction of the cable 137 provides a saw-toothed circular arc 144. A cable lever 145 is rotatably attached to the ratchet plate 143 by a lever pivot joint 146 positioned substantially at the implied centre of the saw-toothed circular arc 144. The cable lever 145 extends away from the lever pivot joint 146 so that the cable lever 154 intersects the saw-toothed circular arc 144. A cable bearing member 147 is rotatably mounted to the ratchet plate 143 at a point which is positioned further in the incident direction of the cable 137 than the lever pivot point 146. The cable 137 wraps around the cable bearing member 147 and the cable 137 is attached to the cable lever at a cable connection point 148 positioned on the cable lever 145 at a point between the lever pivot joint 146 and the saw-toothed circular arc 144. The ratchet plate 143, cable lever 145 and cable bearing member 147 are preferably made from steel.

However, other hard-wearing materials suitable for providing moving mechanism parts 25 may be used. One or more parts can be formed from other materials.

The closing arrangement 48, the cable 137, the ratchet place 143 and the cable lever 145 are configured such that the cable lever 145 extends substantially parallel to the pole axis 19 in the incident direction of the cable 137 when the first and second arm members 28, 31 are in the open clamp position.

The cable lever 145 includes a pawl 149 pivotably mounted to the cable lever 145 and positioned to engage the saw-toothed circular arc 144. The pawl 149 includes a torsion spring (not shown) which maintains the pawl 149 in contact with the saw-toothed circular arc 144. Thus, when the cable lever 145 is pivoted away from the pole 3, the cable 137 is drawn around the cable bearing member 147 and pulled through the cable sheath 142, causing the dosing arrangement 48 to bring the first and second arm members 28, 31 closer together against the biasing of the damping member spring arrangement. When the cable lever 145 has moved sufficiently, the pawl 149 engages the next saw tooth of the saw-toothed circular arc and the cable 137 position becomes temporarily prevented from returning to its initial position. In this way, the cable lever can be used to cause the closing arrangement 48 to close the first and second arm members 28, 31 to securely clamp a tree 5.

A release lever 150 is pivotably mounted to the cable lever 145 by a release lever pivot (c) joint 151. A connection member 152 connects a point on the release lever 150 which is offset from the release lever pivot joint 151 to the pawl 149, such that pivoting the release lever 150 causes the connection member 152 to rotate the pawl 149 against the torsion spring (not shown) and disengage the saw-toothed circular arc 144 of the ratchet plate 143. When the pawl 149 is disengaged from the ratchet plate 143, the biasing force of the clamping member spring arrangement (not shown) causes the first and second arm members 28, 31 to return to the open clamp position and pull the cable 137 back through the cable sheath 142. The pawl 149, release lever 15o and connection member are preferably made from steel. However, other hard-wearing materials suitable for providing moving mechanism parts may be used. One or more parts can be formed from other materials. The connection member 152 need not be rigid and may be a cable.

The closing arrangement 48 need not be a Bowden cable and a ratchet lever. Other closing arrangements may be used such as, for example, a pneumatic or hydraulic piston spanning the first and second arm members 28, 31, and connected to a pumping lever provided proximate to the operator pole end of the pole 3 by a tube which contains air or hydraulic fluid respectively.

First tree-cutting implement A first tree-cutting implement 1 comprises the first tree-cutting head 2, the tubular pole 3 removably coupled to the second fitting 16 of the gimbal joint 9 and a pole axle member (not shown) rotatably mounted inside the pole 3 and removably coupled to the first end n6 of the pole axle coupling member 115.

Towards the operator pole end of the tubular pole 3, there is also provided the ratchet arrangement including the ratchet plate 143 and cable lever 145 hereinbefore described, a motor (not shown) providing driving torque to the pole axle member and, optionally, a steering lever 154 fixedly attached to the pole 3 and extending away from the pole axis 19 so as to enable the operator to apply a larger turning moment to the pole 3. The steering lever 154 is preferably made from aluminium. However, other lightweight structural materials may be used such as magnesium alloy, or structural composite materials such as glass fibre or carbon fibre reinforced composites.

The pole 3 including the rotatably mounted pole axle member may comprise a single piece, or the pole 3 may comprise one or more modular pole segments which may be /o removably coupled together to form a tubular pole 3 of variable length. in the latter case, each modular pole segment includes a pole axle member segment. When the pole 3 is assembled from the modular pole segments, the pole axle member segments may be removably coupled together directly or they may be coupled using additional universal joints.

aeration of the first tree-cutting implement Referring also to Figure 12, operation of the first tree-cutting implement 1 including the first tree-cutting head 2 will now be described in greater detail. Figure 12 shows a schematic geometry of operating the tree cutting implement 1.

When the first clamping assembly 8 has been clamped to the tree 5 using the clamp closing arrangement, the first clamping assembly 8 becomes fixed with respect to the tree 5 and the clamping assembly pivot axis 39 becomes fixed with respect to the tree 5. The first main body 6 of the first tree-cutting head 2 is able to pivot about the clamping -0or assembly pivot axis 39 within the cutting plane 10. The drive shaft axis 18, which is the central axis of the first fitting 15 of the gimbal joint 9, is offset from the clamping assembly axis 39 such that when the first main body 6 pivots with respect to the first clamping assembly 8, the intersection of the drive shaft axis 18 and the cutting plane 10 traces out a circular arc 155.

The first tree-cutting implement 1 starts in the clamping assembly initial position, labelled 156 in Figure 12 and also shown in Figure 3. With the first tree-cutting implement 1 in the clamping assembly initial position 156, the pole axis 19, drive shaft axis 18 and chainsaw axis 24 are in a first set of orientations, and the pole axis 19 makes a first angle 157 with the drive shaft axis 18. When the operator holds a point of the tubular pole 3 proximate to the operator pole end relatively stationary, though free to rotate, and applies a moment to the steering lever 154 to rotate the steering lever 154 to a new position 154b, the end of the pole 3 coupled to the first tree-cutting head 2 is caused to rotate and translate the first main body 6 through a portion of the circular arc 155 to arrive at a clamping assembly second position 158 in which the pole axis 19 has a new position and orientation 19b, the drive shaft axis has a new position and orientation 18b and the chainsaw axis has a new position and orientation 24b.

The gimbal joint 9 and universal joint 127 enable the angle between the pole axis 19 and the drive shaft axis 18 to vary continuously between the initial angle 157 and the final /.0 angle 159. As will be apparent, the first main body 6 may also be moved through an arc in the cutting plane 10 about the clamping assembly pivot axis 39 if the operator applies a combination of rotation and translation of the operator end of the pole 3. This can be advantageous if the operator desires to apply more force to the leading edge 41 of the first chainsaw guide bar 22, or to allow the operator to avoid uneven patches or obstacles on the ground surrounding the tree 5.

Referring also to Figures 13a to 13d, operation of the first tree-cutting implement 1 including the first tree-cutting head 2 will now be described in more detail.

Referring to Figure 13a, the first tree-cutting head 2 is shown with the first clamping assembly 8 and the first main body 6 in the clamping assembly initial position and the first and second arm members 28, 31 of the first clamping assembly 8 in the open clamp position. The first tree-cutting head 2 is maintained with the gimbal joint 9 in the gimbal initial position hereinbefore described by the biasing forces provided by the gimbal joint spring arrangement it This holds the first tree-cutting head 2 steady with the cutting plane 10 perpendicular to the tubular pole 3, enabling the operator to accurately position the first tree-cutting head 2 with the tree 5 located between the opposed teeth 49 of the first and second arm members 28, 31 of the first clamping assembly 8.

Referring next to Figure 13b, the operator actuates the cable lever 145 to cause the closing arrangement 48 to pivot the first and second arm members 28, 31 towards each other together as described in detail hereinbefore. The operator actuates the cable lever 145 until the opposed inwardly facing triangular teeth 49 of the first and second arm members 28, 31 have engaged and securely clamped the tree 5. With the first clamping assembly 8 securely fastened to the tree 5, the operator may change position so as to locate themselves at a point which is not beneath the part 4 which is to be trimmed from the tree 5.

Referring next to Figure 13c, the operator applies a rotation, or a rotation and a translation, to the operator end of the pole 3, causing the first main body 6 to move through a circular arc in the cutting plane 10 about the damping assembly pivot axis 39 against the biasing force of the clamping assembly spring arrangement. The gimbal joint 9 permits the angle between the pole axis 19 and drive shaft axis 18 to continuously vary. The universal joint 127 allows the uninterrupted transmission of torque between the pole axle coupling member 115 and the drive shaft axle member 103 as the orientation of the gimbal joint 9 is altered. As the operator continues to move the first main body 6 through the arc about the assembly pivot axis 39, the chainsaw blade 7 fixedly attached to the first main body 6 intersects and cuts into the tree 5.

Referring next to Figure 13d, the operator continues to cause the first main body 6 to pivot in a circular arc in the cutting plane ro about the damping assembly axis 39 by rotating, or rotating and translating, the operator end of the pole 3 until the chainsaw blade 7 has cut through the tree 5 and severed the part 4.

The first tree-cutting implement 1 can enable an operator to trim parts of trees which are oriented vertically or at an angle within 3o degrees of vertical. The first damping assembly 8 can be caused to clamp the tree 5 using a ratchet assembly so that the operator can clamp the tree and then release the cable lever 145. This can allow the operator to clamp the tree 5 before starting the motor and position themselves safely to make the cut. The simple action of the present invention can reduce the weight and complexity of the first tree-cutting head because additional mechanisms are not required to cause the chainsaw blade 7 to move relative to the first main body 6. The action of the first tree-cutting implement 1 may improve safety because the operator does not need to use a hand for operating controls whilst making a cut, and thus has both of their hands available to support and steer the tubular pole 3.

Second tree-cutting implement and second tree-cutting head A second tree-cutting implement 16o including a second tree-cutting head 161 will now be described.

Referring to Figures 14 and 15, the second tree-cutting implement 160 includes a second tree-cutting head 161 fixedly coupled to the top of the tubular pole 3. The second tree-cutting head 161 is able to rotate about the pole axis 19 by applying torque to the tubular pole 3, and the cutting plane to is fixed substantially perpendicular to the pole axis 19.

Referring in particular to Figure 15, the second tree-cutting head 161 is the same as the first tree-cutting head 2 except that the gimbal joint 9 and universal joint 127 are omitted and the second chassis 162 of the second tree-cutting head 161 includes an aperture providing a seat which is adapted to be coupled directly and fixedly to one end of the tubular pole 3.

The second chassis 162 of the second tree-cutting head 161 has substantially similar shape and internal configuration to the first chassis 12 of the first tree-cutting head 2.

Because the second tree-cutting head 161 does not include a gimbal joint 9, the first fitting 15 of the gimbal joint 9 is not formed as part of the second chassis 162. instead, the tubular pole 3 is directly and fixedly coupled to the base of the second chassis 162. In this example, the second chassis 162 is made from aluminium. However, other lightweight structural materials may be used, for example, magnesium alloy or structural composite materials such as glass fibre or carbon fibre reinforced composites. Other suitable metals can be used, such as, for example, steel or titanium. The second chassis 162 of the second tree-cutting head 161 comprises a chassis case 163 and a chassis lid 164. However, the second chassis 162 may be formed from more or fewer parts depending on the materials and fabrication methods chosen. -0or

The second chassis 162 is directly and fixedly coupled to the top of the tubular pole 3. As shown in Figure 15, in the second tree-cutting implement 160 the drive shaft axle member 103 extends along the tubular pole 3 to also provide the pole axle member. Alternatively, the drive shaft axle member 103 may terminate in an annular sleeve for direct coupling to the end of the pole axle member, or the pole axle member may terminate in an annular sleeve for direct coupling to the drive shaft axle member 103.

The second chassis 162 fixedly receives the tubular pole 3 so that the pole 3 is orientated substantially perpendicular to the cutting plane 10 of the chainsaw blade 7.

The clamping assembly 8 and the clamping assembly pivot joint 37 are substantially the same as those of the hereinbefore described tree-cutting head 2. The second main body 6' may be rotated with respect to the clamping assembly 8 about the clamping assembly pivot axis 39 against the biasing force of the clamping assembly spring arrangement in the same way as hereinbefore described with reference to the first tree-cutting head 2.

Operation of the second tree-cutting implement The operation of the second tree-cutting implement 160 will now be described.

Referring also to Figure 16, the second tree-cutting head 161 is operated in the same way as the first tree-cutting head 2, except that the operator does not vary the angle made between the tubular pole 3 and the cutting plane to whilst severing a trimmed portion 4.

The second tree-cutting implement 16o starts in the clamping assembly initial position 156. With the second tree-cutting implement 16o in the clamping assembly initial position 156, the pole axis 19, drive shaft axis 18 and chainsaw axis 24 are in a first set of orientations, and the pole axis 19 is coincident with the drive shaft axis 18. The pole axis 19 is perpendicular to chainsaw axis 24. The operator holds a point of the tubular pole 3 proximate to the operator pole end and applies a moment to the steering lever 154 to rotate the steering lever 154 to a new position 154b. The end of the pole 3 and the second tree-cutting head 161 are caused to rotate and translate the second main body 6' through a portion of the circular arc 155 to arrive at a clamping assembly second position 158 in which the pole axis 19 has a new position 19b, the drive shaft axis has a new position 18b and the chainsaw axis has a new position 24b. The new pole axis 19b and the new drive shaft axis 18b remain coincident, and the new pole axis 19b remains perpendicular to the new chainsaw axis 24b. As will be apparent, the second main body 6' is moved through an arc in the cutting plane to about the clamping assembly pivot axis 39 by the operator applying a combination of rotation and translation of the operator end of the pole 3. In the operation of the second tree-cutting implement 160, the intermediate positions of the second main body 6', chainsaw blade 7 and tree 5 are the same as those shown in Figures 13a through 13d.

The second tree-cutting implement 16o may be used to cut a trimmed portion 4 oriented vertically or at an angle close to vertical, for example, within ro degrees, within 20 degrees or up to 30 degrees to vertical. The second tree-cutting implement 160 may also be used to sever any tree portion orientated at an angle within 3o degrees of the tubular pole 3. The second tree cutting implement 160 will in general be able to sever any trimmed portion which is capable of being clamped by the clamping assembly 8 and which can be severed by the chainsaw blade 7 when the second main body 6' is moved through the circular arc portion 155 in the cutting plane to.

Third tree-cutting head A third tree-cutting head 165 will now be described.

Referring to Figures 17, 18, 19 and zo, in which Figure zo shows a partial cross section along the line labelled "A" in Figure 18, the third tree-cutting head 165 includes a third main body 6", a second chainsaw guide blade 22' and a second clamping assembly 8'.

The third main body 6" includes a chassis plate 166, a tubular coupling portion 167, a chainsaw sprocket support protrusion 168 and a chainsaw elevation protrusion 169. The chassis plate 166 is broadly rectangular. A rear face 170 of the chassis plate 166 has rounded corners and the chassis plate 166 tapers towards a front face 171. The rear face and front face 171 are at opposed ends of the long direction of the chassis plate 166 and are parallel. A chainsaw axis 172 is located centrally with respect to the chassis plate 166 and is parallel with the long direction of the chassis plate 166. The tubular coupling portion 167 is fixed to a lower surface 173 of the chassis plate 166. The tubular coupling portion 167 is centred on the chainsaw axis 172 and offset towards the rear face 170 of the chassis plate 166. The tubular coupling portion 167 extends perpendicularly from the lower surface 173 of the chassis plate 166, and an annular groove 174 is formed around the circumference of the tubular coupling portion 167.

The chainsaw sprocket support protrusion 168 extends from an upper surface 175 of the chassis plate 166. The chainsaw sprocket support protrusion 168 is substantially cylindrical and is positioned concentrically with the tubular coupling portion 167. A drive shaft through-hole 176 is formed through the chainsaw sprocket support protrusion 168 and the chassis plate 166 to connect to the interior of the tubular coupling portion 167. The chainsaw elevation protrusion 169 is generally a truncated wedge shape, with the narrow end abutting the chainsaw sprocket support protrusion 168 and the wide end flush with the front face 171 of the chassis plate 166. A generally rectangular ridge 177 is positioned centrally with respect to the chassis plate and runs the length of the chainsaw elevation protrusion 169 parallel to the chainsaw axis 172.

An internally threaded chainsaw peg through-hole 178 is formed through the ridge 177, the chainsaw elevation protrusion 169 and the chassis plate 166.

The chainsaw sprocket support protrusion 168 and the chainsaw elevation protrusion 169 extend sufficiently away from the upper surface of the chassis plate 175 to ensure that the chainsaw chain (not shown) is suspended dear of the chassis plate 166 in operation. An internal space 179 is also formed in the chainsaw elevation protrusion 169 which may contain an oil reservoir (not shown) and a pump (not shown) for lubricating the chainsaw chain (not shown). The internal space 179 may also contain a chain tensioning mechanism (not shown) for tensioning the chainsaw chain (not shown).

In this example, the elements forming the third main body 6" are made from aluminium. However, other lightweight structural materials may be used such as magnesium alloy, or structural composite materials such as glass fibre or carbon fibre reinforced composites. Other suitable metals can be used, such as, for example, steel or titanium. Some or all of the chassis plate 166, the tubular coupling portion 167, the chainsaw sprocket support protrusion 168 and/or the chainsaw elevation protrusion 169 may be formed substantially as a single piece, for example, by casting, machining or a combination thereof. Alternatively, some or all of the components of the third main body 6" may be produced separately and joined together using bolts, welding, rivets or other methods of joining which are compatible with the materials used.

The second clamping assembly 8' is the same as the first clamping assembly 8 except that the first protruding member 38 is replaced by a second protruding member 38'. The end of the second protruding member 38' which is not connected to the first arm member 28 forms a tubular pivot portion 180 which surrounds a through-hole 181 which has a diameter large enough to accommodate the diameter of the tubular coupling portion 167. The axis of the through-hole 181 surrounded by the second protruding member 38' is substantially perpendicular to the long axes of the first and second arm members 28, 31. The tubular coupling portion 167 and the second protruding member 38' are preferably made from alumini mum. However, other lightweight structural materials may be used such as magnesium alloy, or structural composite materials such as glass fibre or carbon fibre reinforced composites. Additionally or alternatively, steel or bronze bushings may be included to provide the sliding contact surfaces between the tubular coupling portion 167 and the second protruding member 38', which may help to reduce wear.

-31 -The second chainsaw guide bar 22' is substantially the same as the first chainsaw guide bar 22, except for the replacement of the alignment slot 84 by a second alignment slot 184. The second alignment slot 184 is formed as a rectangular slot with a long axis parallel to the long axis of the second chainsaw guide bar 22'. One end of the second alignment slot 184 is open at the end of the second chainsaw guide bar 22' which lies between the rear face 170 and the front face 171 of the chassis plate 166 when the third tree-cutting head is assembled. The second alignment slot has a width which is just sufficient to receive the ridge 177 and a length which is at least as long as the ridge 177. The second chainsaw guide bar 22' also includes a pair of through-holes 183 which are positioned on opposite sides of the second alignment slot 184. The second chainsaw guide bar 22' is attached to the third main body 6" using chainsaw peg 182. The chainsaw peg 182 is preferably made from steel. However, other hard-wearing materials may be used. The chainsaw peg 182 is externally threaded and is received into the internally threaded though-hole 178. The second chainsaw guide bar 22' is placed in contact with the third main body 6" so that the ridge 177 is mated with the second alignment slot 184 and the chainsaw peg 182 protrudes through the second alignment slot 184. The second chainsaw guide bar 22' is fixedly secured to the third main body 6" by placing a retaining washer 185' over the chainsaw peg 182 and in contact with the second chainsaw bar 22', then threading a retaining nut 185 over the chainsaw peg 182 and tightening the retaining nut 185 against the retaining washer 185'. When the second chainsaw guide bar 22' is assembled to the third main body 6", one of the through-holes 183 is aligned over the internal space 179 to allow access to the chainsaw chain (not shown) by lubricating means (not shown) and/or chain tensioning means (not shown). Alternatively, the chainsaw peg 182, second chainsaw guide bar 22' and third main body 6" may be welded or secured in the relevant positions using any permanent securing method compatible with the materials used. For example, welding, brazing or use of adhesives.

A drive shaft axle 186 is received into the third main body 6" via through-hole 176, and is rotatably mounted to the third main body 6" by first and second drive shaft axle bearings 187, 188. The drive shaft axle 186 and the first and second drive shaft axle bearings 187, 188 are preferably made from steel. However, other hard-wearing materials suitable for providing moving mechanism parts may be used instead. One end of the drive shaft axle 186 protrudes through the chainsaw sprocket support protrusion 168 to receive the chainsaw sprocket 25. The other end of the drive shaft axle 186 extends below the chassis plate into the interior of the tubular coupling portion 167. As shown in Figure 20, in this example the drive shaft axle 186 extends along the tubular pole 3 and provides the pole axle member. However, the pole axle member may be provided as a separate element, in which case the portion of the drive shaft axle 186 which extends into the interior of the tubular coupling portion 167 may include an annular sleeve for coupling the drive shaft axle 186 to the pole axle member. Alternatively, the pole axle member may include an annular sleeve for coupling the pole axle member to the drive shaft axle 186.

The tubular coupling portion 167 is received by the through-hole 181 formed in the o tubular pivot portion 18() of the second protruding member 38'. The second clamping assembly 8' is positioned abutting the lower surface 173 of the chassis plate 166 and is retained in position by a clamping assembly retaining member 189 which mates with the annular groove 174 formed around the outside of the tubular coupling portion 167. Preferably the clamping assembly retaining member 189 is a collar, however, the clamping assembly retaining member 189 may instead be provided by a plurality of pins. The clamping assembly retaining member 189 need not mate with an annular groove 174 formed in the tubular coupling portion 167. Instead, the clamping assembly retaining member 189 may be bolted, pinned or welded to the tubular coupling portion 167 once the second clamping assembly 8' is received over the tubular coupling portion 167. The clamping assembly retaining member 189 retains the second clamping assembly 8' whilst allowing rotation of the second clamping assembly 8' about the axis of the tubular coupling portion 167.

A clamping assembly spring arrangement (not shown) couples the third main body 6" to the second clamping assembly 8'. The clamping assembly spring arrangement is configured to bias the second clamping assembly 8' and third main body 6" to a clamping assembly initial position which is substantially the same as the initial position described hereinbefore in relation to the first tree-cutting head 2. The clamping assembly spring arrangement preferably comprises a torsion spring (not shown) made of steel or other materials with suitable toughness and elastic properties. Alternatively, the clamping assembly spring arrangement may be provided by other types of spring, for example using helical springs spanning from the third main body 6" to the second clamping assembly 8'. The clamping assembly spring arrangement is configured so that the third main body 6" can be pivoted with respect to the second clamping assembly 8' sufficiently to move the second chainsaw guide bar 22' through an arc which spans the second clamping assembly 8'.

The third tree-cutting head 165 includes a clamp closing arrangement 48 which is substantially the same as the first and second tree-cutting heads 2, 161.

Third tree-cutting implement A third tree-cutting implement 190 (Figure 14) will now be described. The third tree-cutting implement 190 is the same as the second tree-cutting implement 166, except that the second tree-cutting head 161 is replaced by the third tree-cutting head 165.

The third tree-cutting head 165 can be mounted to the tubular pole 3 by receiving the tubular pole 3 coaxially into the tubular coupling portion 167 and fixedly coupling the tubular pole 3 to the tubular coupling portion 167. The tubular coupling portion 167 thus forms a seat for coupling the pole 3. The coupling may be temporary using fastening means such as bolts, pins or equivalents, or the coupling may be permanent using attachment methods such as welding, brazing or adhesives. The third main body 6" can be pivoted relative to the second clamping assembly 8' against the biasing of the clamping assembly spring arrangement by rotating the operator end of the tubular pole 3 coupled to the tubular coupling portion 167. Alternatively, the tubular coupling portion 167 could be received into an end of the tubular pole 3.

Operation of the third tree-cutting implement The operation of the third tree-cutting implement 190 (Figure 14) including the third tree-cutting head 165 will now be described. The operation is similar to that of the first and second tree-cutting implements 1, 160. -0or

Referring also to Figure 21, the operator positions the second clamping assembly 8' against a tree 5 and secures the first and second arm members 28, 31 against the tree 5 using the clamp closing arrangement 48. The operator holds the tubular pole 3 and applies a turning moment to the steering lever 154 to move the steering lever 154 to a new position 154b. The torque applied to the steering lever 154 causes the tubular pole 3 and the third main body 6" to rotate about the pivot point with the second clamping assembly 38'. The rotation of the third main body 6" causes the chainsaw blade 7 to sweep across the second clamping assembly 8' and sever the trimmed portion 4 of the tree 5. In operation, both the operator end of the tubular pole 3 and the end of the pole 3 which is fixedly connected to the third main body 6" rotate without substantially translating about the pivot point.

The third tree-cutting implement 190 may be used to cut a trimmed portion 4 oriented vertically or at an angle close to vertical, for example, within ro degrees, within 20 degrees or up to 3o degrees to vertical. The third tree-cutting implement 190 may also be used to sever any tree portion orientated at an angle within 3o degrees of the tubular pole 3. The third tree cutting implement 190 will in general be able to sever any trimmed portion which is capable of being clamped by the second clamping assembly 8' and which can be severed by the chainsaw blade 7 when the third main body 6" is rotated in the cutting plane 10.

Modifications It will be appreciated that many modifications may be made to the embodiments hereinbefore described.

For example, the first tree-cutting head 2 has been described as including a separate sprocket axle member 90 and drive shaft member 103. However, the chainsaw sprocket 25 may be directly attached to the drive shaft axle member 103 with appropriate modifications to the main body 6 and drive shaft axle member 103. In this case, if a gear train is required it may be provided at the operator end of the pole 3 to couple the motor to the pole axle member, reducing the weight of the tree-cutting head.

Alternatively, the motor may be provided as part of the main body 6 and drive the sprocket axle 26 directly.

The drive shaft axis 18, sprocket axis 27 and clamping assembly pivot axis 39 need not -0or be coplanar. Other arrangements of the main body 6 are possible provided that the main body 6 is capable of pivoting with respect to the clamping assembly 8 such that the chainsaw guide bar 22 moves through an arc which at least partially covers the clamping assembly 8.

The first arm member 28 need not be pivotably mounted to the main body 6 using a protruding member 38. Alternative arrangements are possible, such as, for example, the clamping assembly member 129 maybe received directly through the first arm member 28. The clamping assembly member 129 may be received through the through-holes 135, 136 in the first and second arm members 28, 31, such that the clamping assembly pivot joint 37 and the clamping member pivot joint 44 are coaxial.

The gimbal joint 9 and the gimbal spring arrangement 11 need not bias the gimbal joint 9 to a gimbal initial position in which the tubular pole 3 makes an angle of ninety degrees to the cutting plane. Other arrangements are possible such as, for example, the gimbal joint 9 and the gimbal spring arrangement 11 may be configured to provide an initial position in which the tubular pole 3 makes an angle other than ninety degrees to the cutting plane 10. The gimbal joint 9 and the gimbal spring arrangement 11 may be configured so that the angle between the tubular pole 3 and the cutting plane 10 in the gimbal initial position is less than 10 degrees or less than 3o degrees. The gimbal joint 9 and the gimbal spring arrangement 11 may be configured to allow the operator to adjust the gimbal initial position before use, for example by adjusting the tensions of springs included in the gimbal spring arrangement 11.

The first tree-cutting implement 1 has been described as capable of cutting a trimmed portion 4 oriented vertically or at an angle within 3o degrees of vertical. However, with appropriate modifications to the universal joint 127 of the tree-cutting head 2, a tree-cutting implement 1 according to the first example could cut a trimmed portion 4 of a tree 5 oriented vertically or at an angle within 45 degrees of vertical.

The second and third tree-cutting implements 160, 190 have been described with the tubular pole 3 fixedly attached to the second and third main bodies 6', 6" such that the tubular pole 3 is substantially perpendicular to the cutting plane 10. However, the second and third tree-cutting implements 160, 190 may be readily adapted using an angled bracket (not shown) so that the tubular pole 3 is fixedly coupled to the main body 6', 6" at any angle up to 45 degrees from the perpendicular to the cutting plane 10.

or In such examples, a universal joint similar to the universal joint 127 of the first tree-cutting implement 1 may be used to rotatably connect the pole axle to the drive shaft axle member 103. In examples where the tubular pole 3 is fixedly attached to the main body 6', 6" at an angle up to 45 degrees from the perpendicular to the cutting plane 10, the operation of the tree-cutting implement is achieved by using the clamping assembly 8, 8' to clamp a part of a tree 5, then severing a trimmed portion 4 of the tree 5 by moving the operator end of the tubular pole 3 through an arc which causes the main body 6', 6" to pivot with respect to the clamping assembly 8, 8'.

Claims

Claims 1. A tree-cutting head comprising: a chainsaw assembly comprising a main body, a guide bar fixedly attached to the main body, a chainsaw sprocket and a chain wound around the guide bar and sprocket, the guide bar defining a cutting plane; a clamping assembly for removably attaching the tree-cutting head to a tree, the clamping assembly pivotally attached to the main body such that pivoting the main body with respect to the clamping arrangement causes the guide bar to pivot in the cutting plane.
2. A tree-cutting head according to claim 1, wherein the clamping assembly comprises: a first arm having first and second ends; and a second arm having first and second ends; wherein the main body is pivotally attached to the first arm at any point between and including the first and second ends and the second end of the first arm is pivotally attached to the second end of the second arm.
3. A tree-cutting head according to claims 1 or 2, wherein the main body is pivotable with respect to the clamping assembly from a first position towards a second position for cutting the tree and wherein the tree-cutting head further comprises: a first spring arrangement arranged to bias the clamping assembly towards the first position away from the second position.

-0or
4. A tree-cutting head according to claims 2 or 3, wherein the main body is pivotally attached to the first arm at a point proximate to the first end.
5. A tree cutting head according to any preceding claim wherein the first and second arms have an open position for receiving a tree, and the tree cutting head further comprises: a second spring arrangement arranged to bias the first and second arms towards the open position; and a closing arrangement configured to cause the first and second arms to pivot against the biasing of the second spring arrangement.
6. A tree cutting head according to claim 5, wherein the closing arrangement comprises: a cable attached to the second arm between the first and second ends; and an opening attached to the first arm between the first and second ends; wherein the cable passes through the opening and is configured such that in response to the cable being pulled through the opening the second arm is caused to pivotably move relative to the first arm against the biasing of the second spring arrangement.
7. A tree cutting head according to any preceding claim, wherein the main body further comprises a seat configured to couple to a tubular pole which is orientated along an axis substantially perpendicular to the cutting plane.
8. A tree cutting head according to any preceding claim, further comprising a gimbal joint comprising: a gimbal ring; a first fitting pivotally connected to the gimbal ring and attached to the main body offset from the point of attachment of the clamping assembly; and a second fitting pivotally connected to the gimbal ring.
9. A tree-cutting head according to claim 8, further comprising: a universal joint in rotatable communication with the chainsaw sprocket and which passes through the gimbal ring.
10. A tree-cutting head according to claims 8 or 9, further comprising: a third spring arrangement arranged to bias the gimbal joint towards an initial position.u. A tree cutting head according to claim 10, wherein the initial position of the gimbal joint is coaxial alignment.12. A tree-cutting implement comprising: the tree-cutting head according to any preceding claim; a motor in rotatable communication with the chainsaw sprocket; and a tubular pole having first and second ends, wherein the first end of the pole is coupled to the tree-cutting head.13. A tree-cutting implement according to claim 12, further comprising: a pole axle disposed within the pole, wherein a first end of the pole axle is in rotatable communication with the chainsaw sprocket and a second end of the pole axle 5 is in rotatable communication with the motor.14. A tree-cutting implement according to claims 12 or 13, wherein the tubular pole comprises one or more tubular segments configured to be connectable end-to-end.it) 15. A tree cutting implement according to claim 14, wherein the pole axle comprises one or more pole axle segments disposed within corresponding one or more tubular segments and wherein the one or more pole axle segments are configured to be connectable end-to-end.16. A tree-cutting implement according to claim 15, wherein the pole axle segments are configured to be connected to each other by universal joints.17. A tree cutting implement according to any one of claims 12 to 16 when dependent on claim 6, further comprising: a ratchet lever assembly positioned proximate to the second end of the pole and configured to tension the cable.18. A tree-cutting implement according to any one of claims 12 to 17, further comprising: -0or a lever fixedly attached to the pole proximate to the second end and extending substantially perpendicular to the tubular pole.19. A tree-cutting implement according to any one of claims 12 to 18 when dependent from any one of claims 1 to 7, wherein the first end of the tubular pole is coupled to the main body such that the tubular pole is substantially perpendicular to the cutting plane.20. A tree-cutting implement according to claim 19, wherein the tubular pole is coupled to the main body at a point offset from the point at which the clamping assembly is pivotally attached.21. A tree-cutting implement according to any one of claims 12 to 18 when dependent from any one of claims 8 to 11, wherein the first end of the tubular pole is coupled to the second fitting of the gimbal joint.22. A tree-cutting implement according to claim 21 when dependent from claims 9 and 13, wherein the first end of the pole axle is coupled to the universal joint which passes through the gimbal ring.23. A tree-cutting implement according to claims 21 or 22, wherein when the gimbal o joint is in the initial position the tubular pole makes an angle to the perpendicular of the cutting plane of up to 45 degrees, up to 3o degrees, up to 10 degrees or o degrees.24. A method of cutting through a part of a tree using a tree-cutting implement according to any one of claims 12 to 23, the method comprising: clamping the tree-cutting head to the part of a tree; and rotating the pole and/or moving the second end of the pole in an arc.