WO2002062539A1

WO2002062539A1 - Axe with a rotating blade movement and security stop elements adjacent to the blade

Info

Publication number: WO2002062539A1
Application number: PCT/FI2002/000088
Authority: WO
Inventors: Heikki Kärnä
Original assignee: Kaernae Heikki
Priority date: 2001-02-07
Filing date: 2002-02-06
Publication date: 2002-08-15
Also published as: WO2002062539A8; EP1998942A1; FI109184B; FI20010226A0

Abstract

The invention relates to an axe comprising a blade (1) provided with a cutting edge (2) at one end, and a handle (3). The centre of gravity (C) of the axe is located at a distance from the cutting edge (2) of the blade and lies in a centre-of-gravity plane (A) of the axe located at a distance from a blade plane (B) of the axe parallel with both the centre-of-gravity plane and a normal working motion plane (E) of the axe. The cutting edge (2) of the blade and the centre of gravity (C) of the axe are arranged to cooperate when the blade (1) hits wood (4) and the cutting edge (2) of the blade partly penetrates into the wood (4) such that at least some of the impact force of the blade (1) is converted into a rotational motion. On the side of the blade plane (B) of the axe on which the centre of gravity (C) of the axe lies, the axe is equipped with first stop elements (6) arranged to hit the wood (4) during the rotational motion of the blade (1).

Description

AXE WITH A ROTATING BLADE MOVEMENT AND SECURITY STOP ELEMENTS ADJACENT TO THE BLADE.

BACKGROUND OF THE INVENTION

[0001] The invention relates to an axe comprising a blade provided with a cutting edge at one end, and a handle, whereby the centre of gravity of 5 the axe is located at a distance from the cutting edge of the axe and lies in a centre-of-gravity plane of the axe located at a distance from a blade plane of the axe parallel with both the centre-of-gravity plane and a normal working motion plane of the axe, whereby the cutting edge of the blade and the centre of gravity of the axe are arranged to cooperate when the blade hits wood and the 10 cutting edge of the blade partly penetrates into the wood such that at least some of the impact force of the blade is converted into a rotational motion and a motion of the blade in a curvilinear trajectory.

[0002] A normal working motion plane of an axe is herein used to refer to a plane in which the axe is moved while splitting wood. 15 [0003] A centre-of-gravity plane is herein used to refer to a plane which is parallel with the normal working motion plane of an axe and which passes through the centre of gravity of the axe.

[0004] A blade plane is herein used to refer to a plane which is parallel with the normal working motion plane of an axe and which passes through 20 a cutting edge of a blade.

[0005] The normal working motion plane, the blade plane and the centre-of-gravity plane of an axe are parallel with each other and usually vertical.

[0006] A conventional axe is symmetric on both sides of the blade 25 plane. Consequently, the centre-of-gravity plane and blade plane of the axe also coincide.

[0007] A problem with such a conventional axe is that the only way to affect the splitting force is to make the wedge wider. It is, however, difficult for a blade with a wide wedge to penetrate into the wood. In contrast, a blade 30 with a sharp wedge easily penetrates into the wood but has poor splitting force. Therefore, a wedge is always a compromise between good penetration and good splitting force. In addition, a disadvantageous characteristic of the conventional axes is that such an axe gets easily stuck in the wood because the axe blade penetrates directly into the wood. 35 [0008] A solution to the problems with the conventional axe is dis- closed in US 4,300,606, wherefrom an axe according to the preamble of claim 1 is known. The publication discloses an axe head whose blade plane and centre-of-gravity plane are located at a distance from each other, some of the impact force of the axe blade thus being converted into a rotational motion of the axe blade when the blade hits the wood and the cutting edge of the blade partly penetrates into the wood. A rotational motion of the blade makes the wood easier to split.

[0009] A problem with this known arrangement is that when the blade hits the wood and the cutting edge of the blade has partly penetrated into the wood and some of the impact force of the blade is converted into a rotational motion, this rotational motion is uncontrolled. After a piece of wood has been cut off from the wood, the blade continues its rotational motion and, in addition to the rotational motion, the blade also continues its travel in a curvilinear trajectory unless the force runs out. Consequently, the axe disclosed in the US publication may even be a dangerous tool for those unaccustomed to using such^' an axe. The rotational motion of the blade and the motion of the blade in a curvilinear trajectory may result in the user hitting himself or herself in the foot, for example.

BRIEF DESCRIPTION OF THE INVENTION [0010] An object of the invention is thus to provide an axe which alleviates the problems mentioned above.

[0011] The object of the invention is achieved by an axe which is characterized in that on the side of the blade plane of the axe on which the centre of gravity of the axe lies, the axe is equipped with first stop elements arranged to hit the wood during the rotational motion of the blade and the motion of the blade in a curvilinear trajectory.

[0012] Preferred embodiments of the invention are disclosed in the dependent claims.

[0013] The idea underlying the invention is that since the invention comprises first stop elements arranged to hit the wood during the rotational motion of the blade and the motion of the blade in a curvilinear trajectory, the rotational motion of the blade and the motion of the blade in a curvilinear trajectory are under control. Both the rotational motion of the blade and the motion of the blade in a curvilinear trajectory automatically stop completely or at least automatically substantially slow down when the first stop elements hit the wood.

[0014] A further advantage of the axe of the invention is that the first stop elements also improve the way in which wood can be kept in its place on a surface where the wood to be split is placed, since the first stop elements also prevent the wood from ejecting in the opposite direction to that of the rotational motion of the blade and the motion of the blade in a curvilinear trajectory when the first stop elements hit the wood.

[0015] A further advantage of the axe of the invention is that the first stop elements deaden the impact against wood on the side of the axe on which the centre of gravity of the axe lies. This is based on the side of the axe blade usually being substantially flat. When an axe blade comprising a substantially flat side on the side containing the centre of gravity is forced into both a rotational motion and a motion in a curvilinear trajectory and this flat side then hits the wood, the result is a relatively heavy impact. This is because neither the blade nor the wood yields to, i.e. deadens, the impact. The first stop elements operate as deadening elements so as to enable the first stop elements to partly penetrate into the wood, thus slowing down and preferably entirely stopping the motion of the blade before the blade itself, i.e. the side of the blade, hits the wood.

[0016] A still further advantage achieved by the axe of the invention is that since the motion of the blade does not point directly downwards but travels in a curvilinear trajectory and, thanks to the first stop elements, both the rotational motion and the motion in a curvilinear trajectory of the blade are un- der control, the axe of the invention enables also wood on a hard surface, such as a metal or rock surface, to be split since there is no danger of the blade hitting the hard surface.

LIST OF DRAWINGS

[0017] The invention is now described in closer detail in connec- tion with the preferred embodiments and with reference to the accompanying drawings, in which

[0018] Figure 1 is a side view of an axe, [0019] Figure 2 shows the axe as seen from a cutting edge, [0020] Figure 3 shows the axe as seen from an end comprising a blade, and [0021] Figure 4 shows an axe with a shaped handle as seen from the end comprising the blade.

DETAILED DESCRIPTION OF THE INVENTION

[0022] The figures show an axe comprising a blade 1 with a cutting edge 2, and a handle 3.

[0023] The weight of the axe is distributed such that the centre of gravity C of the axe is located at a distance from the cutting edge 2 of the blade and lies in a centre-of-gravity plane A located at a distance from a blade plane B of the axe parallel both with the centre-of-gravity plane A and a normal working motion plane of the axe (not shown in the figures).

[0024] The cutting edge 2 of the blade and the centre of gravity C of the axe are arranged to cooperate when the blade 1 hits wood 4 and the cutting edge 2 of the blade partly penetrates the wood 4 such that at least some of the impact force (not designated by a reference number) of the blade 1 is converted into a rotational motion (not designated by a reference number).

[0025] A rotational motion usually starts no later than when the cutting edge 2 stops penetrating into the wood 4.

[0026] In other words, the cutting edge 2 of the blade and the centre of gravity C of the axe are arranged to cooperate when the blade 1 hits the wood 4 and the cutting edge 2 of the blade partly penetrates into the wood 4 such that at least some of the impact force of the blade 1 is converted into a rotational motion, which makes pieces of wood 5 easier to cut off from the wood 4 or the wood easier to split. After a piece of wood 5 has been cut off from the wood 4, the motion of the blade continues in a curvilinear trajectory. [0027] On the side of the blade plane B of the axe on which the centre of gravity C of the axe lies, the axe is equipped with first stop elements 6 arranged to hit the wood 4 during the rotational motion of the blade 1 and the motion of the blade in a curvilinear trajectory.

[0028] The first stop elements 6 are preferably located on the other side of a plane (not shown in the figures) that lies at right angles to the centre- of-gravity plane A and that passes through the centre of gravity C of the axe as seen from the cutting edge 2 of the blade. By placing the first stop elements 6 in this manner, the blade 1 has enough time to turn (in its rotational motion) when it travels in a curvilinear trajectory long enough to enable the first stop elements 6 to hit the wood 4 in a more advantageous manner. [0029] The figures show an axe wherein the first stop elements 6 are provided in the blade 1 of the axe.

[0030] In the figures, the first stop means 6 comprise two projections. [0031] Alternatively, the first stop means may comprise at least one edge (not shown). The edge may comprise a notch (not shown), for example, provided in one side of the blade 1 of the axe, the notch preferably being substantially parallel with the cutting edge 2 of the blade.

[0032] The first stop elements 6 preferably comprise sharp edges (not designated by a reference number) so as to make them grab or bite into the wood 4 more efficiently when they hit the wood 4.

[0033] Furthermore, on the opposite side to the blade plane B, on which the centre of gravity C of the axe lies, the blade 1 of the axe is preferably equipped with second stop elements 7. The second stop elements 7 are lo- cated at a distance from the cutting edge 2 of the blade. The second stop elements 7 are arranged to stop the blade 1 from penetrating too deeply into the wood 4 and thus to help the rotational motion of the blade to get started. The second stop elements 7 stop the side of the axe blade 1 that is located on the opposite side of the blade plane B of the axe with respect to the centre of grav- ity C of the axe, which means that the motion of the "heavier side" of the axe continues and a rotational motion is achieved.

[0034] In the figures, these second stop elements 7 comprise a second projection comprising an edge substantially parallel with the cutting edge of the blade. [0035] Various methods can be used for moving the centre-of- gravity plane A and the centre of gravity C of the axe to a desired place.

[0036] Figures 1 to 3 show axes wherein the centre of gravity C of the axe with respect to the blade plane B is moved to a desired place by moving the centre of gravity of the blade 1 of the axe itself. [0037] The axe may be equipped with at least one weight 8, for example, arranged to move the centre of gravity C of the axe with respect to the blade plane B. Such a solution enables a conventional "symmetric" axe to be transformed into an axe whose direct motion is converted into a rotational motion when the blade 1 hits the wood 4 and the cutting edge 2 of the blade partly penetrates into the wood 4. Such a weight 8 is preferably attached to the blade 1 of the axe. Alternatively, the weight can be attached to the handle 3 of the axe or both to the blade 1 and the handle 3 of the axe.

[0038] The weight 8 can be a detachable weight, in which case an axe is achieved that is suitable for both forest work and splitting wood. [0039] The axe blade 1 may be asymmetrical such that the centre of gravity C of the axe is moved with respect to the blade plane B of the axe.

[0040] The rotational motion of the blade 1 can also be achieved by using different materials on different sides of the blade plane B of the axe.

[0041] Figure 4 shows an axe wherein the centre of gravity of the axe handle (not designated by a reference number), and thus the centre-of- gravity plane A of the axe, is also located at a distance from the blade plane B of the axe. In Figure 4, the handle 3 of the axe is provided with a bended section 9, in which case when the blade 1 of the axe hits the wood 4, the motion of the bended section 9 of the handle, which was a parallel motion with the blade plane B of the axe before the blade 1 hit the wood, is now converted into a rotational motion, whereby the handle 3 and the blade 1 attached thereto are forced to start the rotational motion. In other words, in the axe according to Figure 4, the cutting edge 2 of the blade and the centre-of-gravity plane of the axe handle are arranged to cooperate when the blade 1 hits the wood 4 and the cutting edge 2 partly penetrates into the wood 4 such that at least some of the swing force of the handle 3 is converted into a rotational motion of the handle 3, which is then conveyed to the blade 1 of the axe.

[0042] Such a handle whose a centre-of-gravity plane has been moved with respect to the blade plane B of the axe could also be used in axes wherein the centre of gravity of the blade has not been moved to a distance from the normal working motion plane of the axe in order to achieve a rotational motion for the blade when the blade hits the wood and the cutting edge partly penetrates into the wood.

[0043] It is obvious to one skilled in the art that as technology ad- vances, the basic idea of the invention can be implemented in many different ways. The invention and its embodiments are thus not restricted to the above examples but may vary within the scope of the claims.

Claims

1. An axe comprising a blade (1 ) provided with a cutting edge (2) at one end, and a handle (3), whereby the centre of gravity (C) of the axe is located at a distance from the cutting edge (2) of the axe and lies in a centre-of-gravity plane (A) of the axe located at a distance from a blade plane (B) of the axe parallel with both the centre-of-gravity plane and a normal working motion plane (E) of the axe, whereby the cutting edge (2) of the blade and the centre of gravity (C) of the axe are arranged to cooperate when the blade (1 ) hits wood (4) and the cutting edge (2) of the blade partly penetrates into the wood (4) such that at least some of the impact force of the blade (1) is converted into a rotational motion and a motion of the blade (1) in a curvilinear trajectory, characterized in that on the side of the blade plane (B) of the axe on which the centre of gravity (C) of the axe lies, the axe is equipped with first stop elements (6) arranged to hit the wood (4) during the rotational motion of the blade (1) and the motion of the blade (1) in a curvilinear trajectory.

2. An axe as claimed in claim 1, characterized in that the first stop elements (6) are provided in the blade (1 ) of the axe.

3. An axe as claimed in claim 1 or 2, characterized in that the first stop means (6) comprise at least one projection.

4. An axe as claimed in claim 1 or 2, characterized in that the first stop means (6) comprise at least one edge.

5. An axe as claimed in any one of claims 1 to 4, characterized in that on the opposite side to the blade plane (B) of the axle, on which the centre of gravity (C) of the axe lies, the blade (1) is equipped with second stop elements (7), the second stop elements (7) are located at a distance from the cutting edge (2) of the blade, and the second stop elements (7) are arranged to stop the blade (1) from penetrating too deeply into the wood (4) before the rotational motion starts.

6. An axe as claimed in claim 5, characterized in that the second stop elements (7) comprise a second projection.

7. An axe as claimed in any one of claims 1 to 6, characterize d in that the axe is equipped with a weight (8) attached to the axe and arranged to move the centre of gravity (C) of the axe with respect to the blade plane (B) of the axe.

8. An axe as claimed in claim 7, characterized in that the weight (8) is attached to the blade (1 ) of the axe.

9. An axe as claimed in any one of claims 1 to 6, character- i z e d in that the blade (1) of the axe is asymmetric such that the centre of gravity (C) of the axe is moved with respect to the blade plane (B) of the axe.

10. An axe as claimed in any one of claims 1 to 9, characterize d in that the centre-of-gravity plane of the handle (3) of the axe is located at a distance from the blade plane (B) parallel therewith, and the cutting edge (2) of the blade and the centre-of-gravity plane of the handle of the axe are arranged to cooperate when the blade (1) hits the wood (4) and the cutting edge (2) of the blade partly penetrates into the wood (4) such that at least some of the swing force of the handle (3) is converted into a rotational motion, which makes pieces of wood (5) easier to cut off from the wood (4).