AU679804B2

AU679804B2 - Portable lifting device

Info

Publication number: AU679804B2
Application number: AU81656/94A
Authority: AU
Inventors: Michael Davis
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-12-21
Filing date: 1994-12-21
Publication date: 1997-07-10
Anticipated expiration: 2014-12-21
Also published as: AU8165694A

Description

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AUSTRALIA

PATENTS ACT 1990 COMP L F TV qP R r T RT r A T T N I FOR A STANDARD PATENT

ORIGINAL

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S

*5 Name of Applicant: Actual Inventor: Address for Service: Invention Title: MICHAEL DAVIS Michael DAVIS SHELSTON WATERS 60 Margaret Street SYDNEY NSW 2000 "PORTABLE LIFTING DEVICE" *o go The following statement is a full description of this invention, including the best method of performing it known to me:-

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2 The present invention relates generally to lifting devices and tools.

The invention has been developed primarily for use as a tool for lifting and supporting logs and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use.

Trees are felled for many reasons such as to provide a source of fuel or building materials, or to clear land for agriculture. Generally, chain saws are used to saw through each tree at its base, causing it to fall under its own weight and rest upon the ground.

It is then often necessary to cut the log into more 15 manageable sections. However, this presents difficulties with the log lying on the ground.

The first problem arises if the operator attempts to saw completely through the log in one cut. Toward S" the end of the cut, there is a strong probability of the chain saw blade contacting the ground. At the very least, this causes premature bluntening or stretching .i of the saw blade. More significantly, however, if the blade strikes a relatively hard obstacle such as a stone or rock as frequently occurs, this can snap the chain altogether, requiring costly replacement and potentially causing serious injury to the operator.

Because of this problem, it is common practice to make a series of transverse cuts each extending only I a -3part way through the log, and then to roll the log through approximately halfa revolution so that the cuts can be completed from the opposite side. However, this is a relatively inefficient and labour intensive procedure because of the need to roll the log, and to stop and start the saw. This is exacerbated when cuts from opposite sides of the log do not accurately intersect, as frequently occurs, necessitating yet further sawing.

In an attempt to ameliorate these problems, various devices such as jacks, winches and slings have been used to support the logs above the ground, and thereby facilitate cutting by chain saw. However, these devices have generally been excessively costly, time consuming to set up, cumbersome to use, difficult to transport, and sometimes unstable to the point of being dangerous.

It is therefore an object of the present invention, at least in its preferred embodiment, to overcome or ameliorate some of these deficiencies of the prior art.

Accordingly, in a first aspect, the invention provides a tool having means for lifting a log from the ground and supporting it in an elevated position combined with an attachment for withdrawing fence posts from the ground, the lifting means comprising a :lever handle having a foot at one end including heel and toe portions, and a gripping arm hingedly mounted to the lever aboN the foot for releasably engaging the log in conjunction with the toe portion, whereby rotation of the lever handle rearwardly onto the heel portion permits the log to be cradled by the tool in an elevated position, the attachment comprising a locking member pivotably mounted to the remote end of the gripping arm for rotation about an axis generally transverse to the gripping arm, said attachment being adapted for loose fitting engagement with the fence post, whereby an initial rearward rotation of the handle from a generally upright orientation pivots the 17745-00 Doc/PAH locking member into frictional engagement with the post and further rotation effects a substantially vertical displacement of the locking member to withdraw the post from the ground, the locking member releasing from the post upon subsequent forward rotation of the handle.

Desirably, further rotation of the lever displaces the centre of gravity of the log across the heel in an overcentring movement, thereby enabling the log to be retained in a stable elevated position with the remote end of the lever handle resting on the ground.

Preferably, the foot includes a curved rolling surface between the heel and the toe o to facilitate rotation onto the heel.

Preferably also, the gripping arm includes a hook at its distal end adapted releasably to engage the log.

Preferably, the locking member includes a pair of spaced apart locking arms. The locking arms preferably extend generally parallel to the axes of rotation of the pivotal arm and the locking member.

15 In a preferred embodiment of the invention, the locking member is generally C- "shaped and configured to engage steel fence posts of a conventional star picket configuration.

A preferred embodiment of the invention will now be described, by way of example only, with reference to 17745.-0 Doc/PAH I I I I the accompanying drawings in which:- Figure 1A is a side elevation showing a tool according to the invention; Figure lB is an enlarged view showing in more detail the operative end of the tool of Figure 1A; Figure 2 is a sectional view taken on line 2-2 of Figure iB; Figure 3 is a side elevation similar to Figure 1A showing the tool undergoing rotation to lift a log; Figure 4 shows the tool cradling the log in a stable elevated position; and Figure 5 shows the tool as used to withdraw a fence post.

Referring firstly to the Figures IA and iB, the 15 invention provides a tool 10 for lifting at least one end of a log from the ground and supporting it in an elevated position. The tool 10 includes a lever handle 12 having a foot 14 at one end including respective S"heel and toe portions 16 and 18. A curved gripping arm 20 is hingedly mounted to the lever handle above the foot 14. The gripping arm 20 includes a hook 24 at its distal end to engage the log in conjunction with the toe portion 18. The foot 14 further includes a curved rolling surface 22 between the heel 16 and the toe 18.

The gripping arm 20 is curved to accommodate the surface profile of the log.

As best shown in Figure 2, heel 16 includes an elongate transverse support member 26 in the form of a .1> 'S,1.

F ~I I '1 length of round bar. In use, the support member 26 extends generally parallel to the log.

Lever handle 12 includes a protuberance 28 disposed generally adjacent the hinged end 30 of the gripping arm 20 to prevent the log rolling down the handle away from the toe 18. Support bracing 31 provides structural support for the protuberance 28 and hinged end 30 of the gripping arm.

The tool further includes triangulated support bracing 32 extending between the heel and the lever handle to provide structural support for the foot 14.

~In the embodiment of the invention shown, the tool further includes an attachment, indicated generally at 34, for withdrawing fence posts from the 15 ground. This attachment comprises a locking member 36 pivotably mounted to the remote end 38 of the gripping arm 20 for rotation about a generally transverse axis.

The locking member 36 is generally C-shaped, defining a pair of spaced apart locking arms 40. 'The arms extend :ooei generally parallel to rotational axes of the gripping arm and the locking member. The attachment 34 is thus adapted for loose fitting engagement with the fence post.

Referring to Figure 3, the operation of the tool will now be described. To lift a log 50 the tool is initially positioned substantially vertically with foot 14 resting on the ground. The tool is then positioned adjacent the log with toe 18 contacting the log I L I 71 surface. Gripping arm 20 is then positioned with hook 24 engaging the surface of the log, as shown. Manual rotation of the lever handle 12 (as indicated by the arrows) rearwardly onto the heel 16 results in log being lifted by the tool and cradled in an elevated position.

Referring to Figure 4, further rotation of the lever handle displaces the centre of gravity of the log across the heel 16 in an overcentring movement. This results in the log being retained in a stable elevated position with the remote end of the lever handle resting on the ground as shown. These lifting and rotational movements are facilitated by the curved rolling surface 22 extending between the heel and the toe. Elongate support member 26 provides lateral stability for the tool in the elevated position and serves to distribute the weight of the log over a larger surface area to reduce the likelihood of the tool sinking into soft soil.

The stable elevated position of the log shown in Figure 5 makes it possible for it to be cut into sections with single cuts by saw 52 because clearance between the log and the ground reduces the possibility of the blades inadvertently contacting the ground.

25 Referring to Figure 5, the tool 10 is shown performing a further function in removing a fence post 54 from the ground.

To remove the fence post, the tool is positioned i I iilil

IN,

14 1substantially vertically with foot 14 on the ground and locking member 36 in loose fitting engagement with the post. In this position the two locking arms 40 are positioned on either side of the fence post. Initial rearward rotation of the lever pivots the locking arms into frictional engagement with the post.

Subsequent rotation effects a corresponding substantially vertical displacement of the locking member 36 to withdraw the post from the ground.

Similar to when lifting logs, the curved rolling surface 22 facilitates rotation onto the heel.

If the post is not fully withdrawn, the lever can be rotated forwardly, whereby the locking member slides down the post, until the tool is again in a 15 substantially vertical orientation, ready for a further iteration.

Due to the large mechanical advantage provided by the tool a large displacement at the lever handle results in a small vertical displacement of the post .5o455 54. Accordingly, several back and forth rotations of the lever may be required to fully withdraw the post from the ground.

In situations where only one of the log lifting or fence pulling functions is required, the tool may be produced without either hook 24 or the locking member 36 as appropriate. However, in its most preferred embodiment the invention conveniently provides for both operations.

%2 I I A tool according to the invention has many advantages over existing techniques for both lifting logs and/or removing fence posts from the ground. It provides a relatively inexpensive and mechanically simple device to allow for the lifting and supporting of logs in a stable and elevated position suitable for cutting. The tool also allows cutting by a single operator and provides a very robust and portable device which may be transported in the back of a utility. The tool is also easy to reposition on the log, resulting in significant time and manpower savings over current ~techniques.

The addition of the fence post removing attachment further enhances the utility of the tool 15 without greatly increasing its complexity. It is thus envisaged that the tool will primarily be used in rural areas where its mechanical simplicity, portability and robust construction increase its desirability over *other, more complex devices.

:eoeI Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

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Claims

2. A tool as claimed in claim I wherein further rotation of the lever displaces the centre of gravity of the log across the heel in an overcentring movement, thereby enabling the log to be retained in a stable elevated position with the remote end of the lever handle resting on the ground.
3. A tool as claimed in claim 1 or claim 2, wherein the foot includes a curved rolling surface between the heel and the toe to facilitate said rotation onto the heel.
4. A tool as claimed in any one of the preceding claims wherein the gripping arm includes a hook at its distal end adapted releasably to engage the log. ~v (4 1774 5-00 DocIPA H 11 A tool as claimed in any one of the preceding claims, wherein the gripping arm is curved to accommodate the surface profile of the log.
6. A tool as claimed in any one of the preceding claims wherein the heel includes an elongate transverse support member, in use, extending generally parallel to the log to provide lateral stability for the tool in the elevated position.
7. A toi, as claimed in claim 6 wherein said support member comprises a length of round bar. A tool as claimed in any one of the preceding claims wherein the lever includes a protuberance disposed generally adjacent the hinged end of the gripping arm to prevent i 10 the log rolling down the handle away from the toe.
9. A tool as claimed in any one of the preceding claims wherein triangulated support bracing extends between the heel and the lever to provide structural support for the foot.
10. A tool as claimed in any one of the previous claims wherein said locking member includes a pair of spaced apart locking arms extending generally parallel to the axes of 15 rotation of the pivotal arm and the locking member.
11. A tool as claimed in any one of the previous claims wherein the locking member is generally C-shaped.
12. A tool as claimed in one of the previous claims wherein the locking member is configured to engage steel fence posts of a conventional star picket configuration.
17745.00ooDoc/PAH I CL -12- 13. A tool substantially as hereinbefore described with reference to the accompanying drawings. DATED this 27 Day of March 1997 MICHAEL DAVIS Attorney: STUART M. SMITH Fellow Institute of Patent Attorneys of Australia of SHELSTON WATERS 177 ABSTRACT A tool (10) for lifting a log from the ground and supporting it in an elevated position. The tool includes a lever handle (12) having a foot (14) at one end including heel and toe portions (16,18), and a gripping arm (20) hingedly mounted to the lever above the foot The gripping arm is adapted to releasably engage the log in conjunction with the toe portion whereby rotation of the lever handle (12) rearwardly onto the heel (16) permits the log to be cradled by the tool (10) in an elevated position. **see: *1 *6°000 0 SO.. I