WO2010092319A1

WO2010092319A1 - Arborist tool

Info

Publication number: WO2010092319A1
Application number: PCT/GB2010/000055
Authority: WO
Inventors: Reg Coates
Original assignee: Reg Coates
Priority date: 2009-02-10
Filing date: 2010-01-14
Publication date: 2010-08-19
Also published as: GB0902165D0; GB2467733A

Abstract

An arborist tool (10) for raising and lowering tree trunks and branches is provided having a base plate (13) which is attached by a strap (16) to the base of a tree and on which at least one capstan (14, 15) is mounted. A rope gripping device (12) in the form of a two-part lever (23, 24) is pivotally mounted on the base plate (13) for movement towards and away therefrom, and is operable in operation to grip a rope (30) passing therethrough when the rope gripping device (12) is moved towards the base plate (13) and to release the rope (30) when the rope gripping device (12) is moved away from the base plate (13). The lever parts (23, 24) are pivotally attached to each other, with an anvil (28) on one part (23) and a clamp means (29) on the other part (24), the rope (30) passing in a convoluted path between the anvil (28) and clamp means (29). Two spaced axially parallel capstans (14, 15) may be mounted on the base plate (13).

Description

ARBORIST TOOL

This invention relates to arborist tools, and in particular to tools for use in felling and de- branching trees.

The procedure adopted for felling or de-branching a tree varies considerably with the location of the tree and its size or that of the branch. If the tree or branch will not foul other trees, buildings or other obstructions, the tree may be felled by saw or axe cutting at the tree near to the ground, or the branch may be cut from the tree and lowered directly down to the ground. However, if there are obstructions in the vicinity of the tree, it is customary to fell the tree by "sectional felling", or branch removal may be done by raising the branch and moving it laterally to a position from which it can be lowered to the ground without fouling any obstruction. Sectional felling involves first lopping the branches from the trunk and then progressively removing section by section the uppermost section of the trunk. Hence this operation may require.the branch removal operation referred to above.

The branch lowering operation usually involves attaching one end of a rope to the branch before cutting it from the tree, passing the rope over a pulley secured above the branch to be removed and then passing the other end of the rope around a capstan device secured to the ground or base of the tree. By gradually reducing the tension in the free end of the rope and allowing rotation of the capstan or the rope to slip around the capstan, the branch after cutting can be lowered in a controlled manner. In order to raise the branch, it is customary to use a ratchet capstan, whereby rotation of the capstan over its internal ratchet pulls downwardly on the rope issuing therefrom and hence upwardly on the length of rope between the pulley and the branch. Such devices are relatively costly to manufacture, but raising and lowering tree trunks and branches without such devices is dangerous for the personnel involved. It is an object of the present invention to provide a less costly alternative device, but which is equally simple in operation and safe to use as the known devices. The invention provides an arborist tool comprising a base unit having at least one capstan mounted thereon, a rope gripping device mounted on the base unit for movement towards and away therefrom, wherein the rope gripping device is operable in operation to grip a rope passing therethrough when the rope gripping device is moved towards the base unit and to release said rope when the rope gripping device is moved away from the base unit.

The rope gripping device may comprise an elongate lever, which may be pivotally mounted on the base unit. The lever may comprise an anvil part and a gripping part, and the gripping part may b© attached to the anvil part for relative movement therebetween. The anvil part may have a proximal end thereof pivotally attached to the base unit, and may have an anvil secured thereto at a distal end thereof. The gripping part may pivotally attached to the anvil part, and may have a proximal end thereof attached at the distal end of the anvil part. The gripping part may have clamp means secured thereto at the proximal end thereof.

The anvil and the clamp means may comprise a plurality of cylindrical members, which may interleave when the clamp means is moved into a rope gripping position relative to the anvil. A rope retaining means may be attached to one of said anvil or clamp means. A hand guard plate may be secured to the anvil part at the distal end thereof. The rope gripping device may be removably attached to the base unit.

The base unit may comprise a base plate on which the at least one capstan is mounted. The base plate may have two capstans mounted thereon, in which case the capstans may be in a substantially axially parallel, spaced disposition. The rope gripping device may be pivotally mounted on the base plate at a position remote from the capstan or capstans. The base plate may have tree engaging means attached thereto, and the engaging means may be in the form of a strap passing in use around the standing trunk of a tree. The base plate may have loops attache'd thereto through which the strap may pass. The base plate may also have at least one additional loop through which an additional or "choker" strap may pass. The base plate may have protrusions on the side thereof that in use lies against a tree, and the protrusions may comprise ribs.

The invention will now be further described with reference to the accompanying drawings in which:

Fig. 1 is a front elevation of an arborist tool in accordance with the invention,

Fig 2 is a plan view of the tool of Fig. 1 with the rope gripping means detached from the base unit,

Fig. 3 is an enlarged front view of the rope gripping means in an open position, and Fig. 4 is an enlarged front view of the rope gripping means in a rope gripping position.

Referring now to Figs. 1 and 2, there is shown an arborist tool 10 comprising a base unit 11 and a rope gripping device 12. The base unit 10 comprises a base plate 13 on which two capstans 14, 15 are mounted in a substantially axially parallel, spaced disposition. The base unit 11 may be attached to a tree (not shown) by means of a strap 16 which passes through two loops 17 provided on the base plate 13. The strap 16 is tightened around the base of the tree in conventional manner. To strengthen the base plate 13 and to prevent the strap 16 from chafing between the tree and the base plate 13, ribs 18 are provided on the rear face of the base plate 13. The ribs 18 also "bite" into the tree to stabilise the tool 10 on the tree. As a safety precaution, an additional loop 19 is provided on the base plate 13, through which an additional or "choker" strap (not shown) may pass in case the main strap 16 fails to secure the tool 10 to the tree. To facilitate the threading of the choker strap through the loop 19, the loop 19 may lie out of the plane of the base plate 13. Attached to the base plate 13 is an upstanding post 20 which is braced by a bracing strut 21. At the upper end of the post 20 is a pivot pin 22.

Referring now to Figs. 1 to 4, the rope gripping device 12 is in the form of an elongate lever having an anvil part 23 and a gripping part 24. Attached to a proximal end of the anvil part 23 is a pivot bush 25, into the bore 26 of which the pivot pin 22 is received (as shown by the dashed arrow in Fig. 2) when the rope gripping device 12 is pivotally mounted on the base unit 11. A proximal end of the gripping part 24 is attached to the distal end of the anvil part 23 by means of pivot 27. At the distal end of the anvil part 23 is an anvil 28, and at the proximal end of the gripping part 24 is a clamp means 29. When the gripping part 24 is raised (i.e. away from the base unit 11) as shown in Fig. 3, the clamp means 29 is spaced from the anvil 28 whereby a rope 30 (Figs. 1 and 4) can pass freely therebetween. When the gripping part 24 is moved 'downwardly (i.e. towards the base unit 11) as shown by the arrow in Fig. 3 to the position shown in Figs. 1 and 4, the rope 30 is engaged between the clamp means 29 and the anvil 28. Both the clamp means 29 and the anvil 28 comprise several cylindrical members which interleave when in this rope engaging position. This configuration of clamp means 29 and anvil 28 provides that the rope 30 traverses a convoluted path between them (see Fig. 4), so that gripping of the rope 30 relies on friction as well as the clamping effect. To safeguard against a person trapping their fingers between the clamp means 29 and the anvil 30, a hand guard plate 31 is attached to the distal end of the anvil part 23. In addition, to prevent the rope 30 from slipping from between the clamp means 29 and the anvil 28 as they move together or apart, a rope retaining means 32 is attached to the anvil 28. The rope retaining means 32 can be rotated between an open position as shown in Fig. 3 facilitating threading of the rope 30 between the anvil 28 and the clamp means 29, and a closed position as shown in Fig. 4.

Operation of the arborist tool 10 in raising and lowering a heavy tree branch is as follows. The arborist tool 10 is secured to the base of a tree by means of the main strap 16 in conventional manner. For safety reasons a choker strap may also be used. A rope 30 is secured to the branch to be removed and passed through a pulley that is secured to the tree above the location of the branch concerned. The rope 30 then passes through the open clamp means 29 and anvil 28, the rope gripping device 12 being in a raised position, to pass around the capstan 14 one or more times as required dependent on the estimated weight of the branch. The tension in the rope 30 is sufficient to prevent substantial lowering of the branch when it is cut from the tree. After cutting, the rope gripping device 12 is lowered towards the base unit 11 , thereby causing the rope 30 to be gripped between the clamp means 29 and the anvil 28. Further lowering of the rope gripping device 12 pulls the rope 30 downwardly, thereby raising the branch. The slack rope 30 below the rope gripping means 12 is pulled around the capstan 14, and friction prevents the rope 30 from slipping back. The rope gripping device 12 is then raised, releasing the rope 30 from between the clamp means 29 and the anvil 28, and the process is repeated as many times as necessary to lift the branch clear of any obstacle. Tension in the rope 30 around the capstan 14 may then be reduced to allow lowering of the branch to the ground. For purely lowering purposes, the rope gripping device 12 may be removed from the base unit 11. For particularly heavy branches, the rope 30 may be passed around both capstans 14, 15, or two ropes may be employed, one passing around capstan 14 and a second rope passing around capstan 15. Alternatively, the second rope may be attached to a second branch whereby two branches may be removed without having to reset the positions of the tool 10 or pulley at the upper part of the tree.

Other embodiments of arborist tool in accordance with the invention will be readily apparent to persons skilled in the art. For example, the anvil and gripping means may comprise serrated blocks. The tree engaging means may comprise tree gripper devices adapted to engage the standing tree trunk at opposed sides thereof. The gripping part 24 may be slidable longitudinally of the anvil part 23 instead of being pivotally mounted thereon, or the rope gripping means 12 may comprise a single lever on which the clamp means 29 or anvil 28 are movable to grip or release the rope 30.

Claims

1. An arborist tool (10) comprising a base unit (11) having at least one capstan (14, 15) mounted thereon, characterised by a rope gripping device (12) mounted on the base unit (11) for movement towards and away therefrom, wherein the rope gripping device (12) is operable in operation to grip a rope (30) passing therethrough when the rope gripping device (12) is moved towards the base unit (11) and to release said rope (30) when the rope gripping device (12) is moved away from the base unit (11).

2. An arborist tool as claimed in claim 1 , characterised in that the rope gripping device (12) comprises an elongate lever (23, 24).

3. An arborist tool as claimed in claim 2, characterised in that the lever (23, 24) is pivotally mounted on the base unit (11).

4. An arborist tool as claimed in claim 3, characterised in that the lever (23, 24) comprises an anvil part (23) and a gripping part (24).

5. An arborist tool as claimed in claim 4, characterised in that the gripping part (24) is attached to the anvil part (23) for relative movement therebetween.

6. An arborist tool as claimed in claim 4 or claim 5, characterised in that the anvil part (23) has a proximal end pivotally attached to the base unit (1 1).

7. An arborist tool as claimed in claim 6, characterised in that the anvil part (23) has an anvil (28) secured thereto at a distal end thereof.

8. An arborist tool as claimed in any one of claims 5 to 7, characterised in that the gripping part (24) is pivotally attached to the anvil part (23).

9. An arborist tool as claimed in claim 8, characterised in that the gripping part (24) has a proximal end attached at the distal end of the anvil part (23).

10. An arborist tool as claimed in claim 9, characterised in that the gripping part (24) has clamp means (29) secured thereto at the proximal end thereof.

11. An arborist tool as claimed in claim 10, characterised in that the anvil (28) and the clamp means (29) comprise a plurality of cylindrical members.

12. An arborist tool as claimed in claim 11 , characterised in that the cylindrical members interleave when the clamp means (29) is moved into a rope gripping position relative to the anvil (28).

13. An arborist tool as claimed in any one of claims 10 to 12, characterised in that a rope retaining means (32) is attached to one of said anvil (28) or clamp means (29).

14. An arborist tool as claimed in any one of claims 10 to 13, characterised in that a hand guard plate (31) is secured to the anvil part (23) at the distal end thereof.

15. An arborist tool as claimed in any one of claims 1 to 14, characterised in that the rope gripping device (12) is removably attached to the base unit (11).

16. An arborist tool as claimed in any one of claims 1 to 15, characterised in that the base unit (11) comprises a base plate (13) on which the at least one capstan (14, 15) is mounted.

17. An arborist tool as claimed in claim 16, characterised in that the base plate (13) has two capstans (14, 15) mounted thereon.

18. An arborist tool as claimed in claim 17, characterised in that the capstans (14, 15) are in a substantially axially parallel, spaced disposition.

19. An arborist tool as claimed in claim 17 or claim 18, characterised in that the rope gripping device (12) is pivotally mounted on the base plate at a position remote from the capstan or capstans (14, 15).

20. An arborist tool as claimed in any one of claims 16 to 19, characterised in that the base plate (13) has tree engaging means (16) attached thereto.

21. An arborist tool as claimed in claim 20, characterised in that the engaging means (16) is in the form of a strap (16) passing in use around the standing trunk of a tree.

22. An arborist tool as claimed in claim 21 , characterised in that the base plate (13) has loops (17) attached thereto through which the strap (16) may pass.

23. An arborist tool as claimed in claim 22, characterised in that the base plate (13) has at least one additional loop (19) through which an additional or "choker" strap may pass.

24. An arborist tool as claimed in any one of claims 16 to 23, characterised in that the base plate (13) has protrusions (18) on the side thereof that in use lies against a tree.

25. An arborist tool as claimed in claim 24, characterised in that the protrusions (18) comprise ribs (18).

26. An arborist tool substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 4 of the accompanying drawings.