BACKGROUND OF THE INVENTION

The present invention relates to a lifting hook for locking a hand-held work tool to a carabiner attached to the body of a worker.

A work tool including a power source such as an electric motor or an internal combustion engine is linked to a worker by using a lifting hook and a carabiner during work or interruption of work. Japanese Laid-Open Patent Publication No. 2015-39328 discloses an example in which a worker wears a harness including a hip pad to use a combination of a lifting hook and a carabiner for linking the harness to a bush cutter. Japanese Laid-Open Patent Publication No. 2011-101919 discloses an example in which a combination of a lifting hook and a carabiner is used to suspend a rechargeable electric work tool from a waist belt of a worker when the tool is not in use.

Several typical examples of conventional lifting hooks manufactured by bending one rod will be described with reference to Japanese Laid-Open Patent Publication No. 2009-269153, WO 2010/077195, and Japanese Laid-Open Patent Publication No. 2016-199005.

Japanese Laid-Open Patent Publication No. 2009-269153 proposes a lifting hook locking a hand-held work tool such as an electric screwdriver or an electric or gas-combustion tacker to a waist belt. This lifting hook is for directly locking to the waist belt.

WO 2010/077195 and Japanese Laid-Open Patent Publication No. 2016-199005 propose lifting hooks locking a work tool to a waist belt via a carabiner or a rope attached to the waist belt, and these hooks have a flat U-shape, are both pivotally assembled to the work tool, and can take a use position projected from the work tool and a retracted position housed in a recess of the work tool.

The lifting hook of WO 2010/077195 is located on a vertical plane when the hook is attached to a work tool. The lifting hook of Japanese Laid-Open Patent Publication No. 2016-199005 is located on a horizontal plane when the hook is attached to a work tool. As used herein, the term “vertical” means, for example, a body height direction, i.e., an up-down direction, when a worker with the carabiner disposed on a waist belt takes a standing posture and holds the work tool in a natural posture. The term “horizontal” means a lateral direction orthogonal to the body height direction. As used herein, the term “natural posture” means a state in which the worker holds the work tool without twisting the wrist.

To distinguish the lifting hooks disclosed in WO 2010/077195 and Japanese Laid-Open Patent Publication No. 2016-199005, the lifting hook of WO 2010/077195 is referred to as a “vertical hook”, and the lifting hook of Japanese Laid-Open Patent Publication No. 2016-199005 is referred to as a “horizontal hook”.

Available carabiners can roughly be classified into two types. A first type is a “lever type carabiner” including a gate lever. A second type is a “safety lock type carabiner” including a locking mechanism using a screw. The lever type carabiner is employed to link a hand-held work tool to the body of a worker.

The lever type carabiners can roughly be classified into two types depending on a length of a nose defining a gate portion of a carabiner body. Typical examples of carabiners employed for locking a hand-held work tool are shown inFIGS. 29 and 30. A carabiner2ofFIG. 29is a “short-nose carabiner”. A carabiner4ofFIG. 30is a “long-nose carabiner”.

Referring toFIG. 29, the short-nose carabiner2has a carabiner body10, a gate lever14disposed in a gate portion12of the carabiner body10, and a nose part16with which a free end of the gate lever14is engaged. The gate lever14has a structure providing a spring function, and this spring function constantly urges the gate lever14in the closing direction. The long-nose carabiner4(FIG. 30) includes substantially the same constituent elements and additionally has a spring member (not shown) urging the gate lever14. This spring member constantly urges the gate lever14of the long-nose carabiner4in the closing direction. The short-nose carabiner2and the long-nose carabiner4have a base end14aof the gate lever14pivotally supported by the carabiner body10.

As can be seen by comparingFIGS. 29 and 30, the nose part16of the short-nose carabiner2has a shorter distance L(s) from a locking point16afor locking the free end of the gate lever14to a tip16b. On the other hand, the long-nose carabiner4has a longer distance L(L) from the locking point16ato the tip16b, and the nose part16from the locking point16ato the tip16b, i.e., a nose extension part18is curved outward (FIG. 30).

To attach a lifting hook of a work tool to the lever type carabiner and to remove the hook from the carabiner, a worker is required to perform an operation of pushing down and opening the gate lever14against the spring force. Operations of the worker holding the work tool employing the vertical hook (WO 2010/077195) or the horizontal hook (Japanese Laid-Open Patent Publication No. 2016-199005) will hereinafter be described with reference toFIGS. 31 to 46.

Combination of Vertical Hook and Short-Nose Carabiner

FIGS. 31 and 32are views for explaining an operation at the time of attaching a vertical hook20to the short-nose carabiner2. In the figures, “Wk” denotes a worker. “Wb” denotes a waist belt. The vertical hook20is disposed on a rear end surface of a work tool TL. The work tool TL shown in the figures is illustrated as a rechargeable electric chainsaw. This chainsaw TL is a top handle type.

FIG. 31shows a preparation step for attaching the vertical hook20to the short-nose carabiner2. The worker Wk lifts the chainsaw TL and rotates an arm Am and/or a wrist Wr, i.e., twists the arm Am and/or the wrist Wr, to position an upper leg20uof the vertical hook20on the free end of the gate lever14and position a lower leg20doutside the nose part16.

FIG. 32shows a step of pushing down the gate lever14against the spring force with the upper leg20uof the vertical hook20and inserting the upper leg20uinto the carabiner body10. This step can be performed by the worker Wk rotating and pushing down the chainsaw TL. As a result, the gate lever14is opened against the spring force, and the upper leg20ucan be inserted into the carabiner body10. The gate lever14is then automatically closed by the spring force. By the operation described above, the vertical hook20is completely attached to the short-nose carabiner2, and the chainsaw TL is engaged with the carabiner2via the vertical hook20. Consequently, the chainsaw TL is suspended from the waist of the worker Wk via the carabiner2.

FIGS. 33 and 34are views for explaining an operation of detaching the vertical hook20locked to the short-nose carabiner2from the carabiner2.FIG. 33shows a detachment preparation step. The worker Wk moves the arm Am upward to lift the chainsaw TL and then performs an operation of bringing the chainsaw TL closer to the body side of the worker Wk. As a result, the lower leg20dof the vertical hook20can be located on a free end portion of the gate lever14.

FIG. 34is a view for explaining an operation of pushing down the lower leg20dlocated on the free end portion of the gate lever14and inserting the lower leg20dinto the carabiner body10. This operation is performed by the worker Wk lowering the arm Am and pushing down the chainsaw TL. As a result, both the upper leg20uand the lower leg20dcan be inserted into the carabiner body10. Subsequently, by moving the arm Am forward or downward from this state, the vertical hook20located inside the carabiner body10can be pulled out. By the operation described above, the vertical hook20is completely detached from the short-nose carabiner2, and the chainsaw TL is released from the carabiner2.

Combination of Horizontal Hook and Short-Nose Carabiner

FIGS. 35 and 36are views for explaining an operation at the time of attaching a horizontal hook30to the short-nose carabiner2.FIG. 35shows a preparation step for attaching the horizontal hook30to the short-nose carabiner2. The worker Wk lifts the chainsaw TL and rotates the arm Am or twists the wrist Wr to face the rear end surface of the chainsaw TL toward the body side. A connecting part30cnconnecting ends of an inner leg30in and an outer leg30out of the horizontal hook30is positioned on the free end portion of the gate lever14.

FIG. 36shows a step of inserting the connecting part30cnof the horizontal hook30into the carabiner body10. This inserting step can be performed by pushing down the chainsaw TL. This causes the connecting part30cnto open the gate lever14against the spring force, and the connecting part30cnis inserted into the carabiner body10. As a result, the horizontal hook30is completely attached to the short-nose carabiner2, and the chainsaw TL is engaged with the carabiner2via the horizontal hook30.

FIGS. 37 and 38are views for explaining an operation of detaching the horizontal hook30attached to the short-nose carabiner2from the carabiner2.FIG. 37shows a detachment preparation step. The worker Wk lifts and rotates the arm Am to position the outer leg30out of the horizontal hook30on the gate lever14.FIG. 38shows a step of inserting the outer leg30out of the horizontal hook30into the carabiner body10. This step can be performed by pushing down the chainsaw TL with the arm Am. As a result, both the inner leg30in and the outer leg30out can be inserted into the carabiner body10. Subsequently, by moving the arm Am forward from this state, the horizontal hook30located inside the carabiner body10can be pulled out. As a result of the operation, the horizontal hook30is completely detached from the short-nose carabiner2, and the chainsaw TL is released from the carabiner2.

Combination of Vertical Hook and Long-Nose Carabiner

FIGS. 39 and 40are views for explaining an operation at the time of attaching the vertical hook20to the long-nose carabiner4.FIG. 39shows an attachment preparation step. The worker Wk lifts the rear end surface of the chainsaw TL and twists the arm Am and/or the wrist Wr to position the lower leg20dof the vertical hook20on the free end of the gate lever14and position the upper leg20uoutside the nose extension part18.

FIG. 40shows a step of pushing down the gate lever14with the lower leg20dof the vertical hook20to insert the lower leg20dinto the carabiner body10. This step can be performed by the worker Wk pushing down the chainsaw TL. By this operation, the vertical hook20is completely attached to the long-nose carabiner4, and the chainsaw TL is engaged with the carabiner4via the vertical hook20.

FIGS. 41 to 43are views for explaining an operation of detaching the vertical hook20locked to the long-nose carabiner4from the carabiner4.FIG. 41shows a detachment preparation step. Referring toFIG. 41, first, the worker Wk lifts the chainsaw TL to raise the upper leg20uof the vertical hook20along the nose extension portion18so that the upper leg20uthen climbs over the nose extension portion18.FIGS. 42 and 43show a step of inserting the upper leg20uinto the carabiner body10. This step is performed by pushing down the free end portion of the gate lever14with the upper leg20u. Specifically, the worker Wk pushes down the chainsaw TL to open the gate lever14against the spring force with the upper leg20u, and the upper leg20ucan then be inserted into the carabiner body10(FIG. 43). Subsequently, by moving the arm Am forward, the vertical hook20located inside the carabiner body10can be pulled out. By the operation described above, the vertical hook20is completely detached from the long-nose carabiner4, and the chainsaw TL is released from the carabiner20.

Combination of Horizontal Hook and Long-Nose Carabiner

FIGS. 44 and 45are views for explaining an operation at the time of attaching the horizontal hook30to the long-nose carabiner4.FIG. 44shows an attachment preparation step. The worker Wk lifts and brings the chainsaw TL closer to the body side so that the horizontal hook30climes over the nose extension part18(FIG. 44). The chainsaw TL is then pushed down to open the gate lever14against the spring force (FIG. 45), and the horizontal hook30is inserted into the carabiner body10. When this is finished, the gate lever14automatically returns to the closed state due to the spring force. By this series of operations, the horizontal hook30is completely attached to the long-nose carabiner4, and the chainsaw TL is engaged with the long-nose carabiner4via the horizontal hook30.

FIG. 46is a view for explaining an operation of detaching the horizontal hook30locked to the long-nose carabiner4from the carabiner4. The worker Wk lifts the chainsaw TL to raise the outer leg30out of the horizontal hook30along the nose extension part18and moves the outer leg30out by rotating the wrist Wr upward and sideways, i.e., by a twisting motion of the wrist Wr, to climb over the nose extension part18. The outer leg30out is positioned on the free end of the gate lever14and is then pushed down. Specifically, the worker Wk pushes down the chainsaw TL to open the gate lever14with the outer leg30out and inserts the outer leg30out into the carabiner body10. Subsequently, by moving the arm Am forward, the horizontal hook30located in the carabiner body10can be pulled out. By the operation described above, the horizontal hook30is completely detached from the long-nose carabiner4, and the chainsaw TL is released from the carabiner4.

As described above, to lock/detach the conventional vertical or horizontal hook20,30to/from the short-nose or long-nose carabiner2,4, the worker Wk needs to perform an up-down motion and a rotating motion of the arm (arm twisting motion) and an up-down motion or left/right rotating motion of the wrist Wr (wrist twisting motion). Explaining an example of a situation where the chainsaw illustrated as the work tool TL is locked to the carabiner2,4, when pruning and trimming a tree, a worker Wk climbs the tree by using a rope etc. and performs a work while moving on the tree. When the chainsaw is not used, the worker Wk moves, or performs another work, while the chainsaw is locked to the carabiner2,4on a waist belt Wb. In such an unstable state, it is required to simplify the motions of the arm Am, a hand Hd, and the wrist Wr related to the operation of the worker Wk locking/detaching the hook20,30to/from the carabiner2,4as much as possible.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a lifting hook capable of simplifying a worker's motion for locking to/detaching from a carabiner attached to the worker's body to reduce a burden of the worker.

According to one aspect of the present invention, the technical problem described above is solved by providing a lifting hook comprising:

an inner leg (102) and an outer leg (104) fixed to a work tool (TL) with a power source; and

a connecting part (106) connecting free ends of the inner and outer legs to each other, wherein

when a worker equipped with a lever-type carabiner (2,4) holds the work tool (TL), the inner leg (102) of the lifting hook is located on the inner side close to the carabiner (2,4) while the outer leg (104) is located on the outer side far from the carabiner (2,4), wherein

the inner leg (102) and the outer leg (104) have a height difference (H) so that at least a portion of the outer leg (104) is located higher than the inner leg (102), and wherein

since the inner leg (102) and the outer leg (104) have a height difference (H), the inner leg (102), the connecting part (106), and the outer leg (104) form a three-dimensional shape.

According to another aspect of the present invention, the present invention can be defined by a lifting hook comprising:

an inner leg (102) and an outer leg (104) fixed to a work tool (TL) with a power source; and

a connecting part (106) connecting free ends (102a,104a) of the inner and outer legs (102,104) to each other, wherein

when a worker equipped with a lever-type carabiner (2,4) holds the work tool (TL) in a natural posture without twisting the wrist, the inner leg (102) of the lifting hook is located on the inner side close to the carabiner (2,4) while the outer leg (104) is located on the outer side far from the carabiner (2,4), and wherein

the inner leg (102) and the outer leg (104) have a height difference (H) so that at least a portion of the outer leg (104) is located higher than the inner leg (102).

Effects and other objects of the present invention will become apparent from the following detailed description of preferable examples of the present invention.

