Field of Invention The present invention relates to a power tool such as a chainsaw. Particularly but not exclusively, the present invention also relates to a power tool having a deflector for directing saw dusts away from the operator during cutting.

Background of the Invention

Conventional power tools such as chainsaws or circular saws have been commonly used for cutting a work piece or trees. When the blade engages the subject to be cut during the cutting action, debris such as saw dusts or wood chips will propel upwardly and outwardly from the cutting site. This is particularly undesirable for portable tools of which the operator would be handling the tool at a closer distance from the cutting site during the operation, and therefore a significant amount of the propelling saw dusts or chips is likely to reach the operator.

Summary of the Invention In accordance with a first aspect of the present invention, there is provided a power tool comprising: a body having a motor arranged to drive an operation member adapted to perform an operation capable of generating debris, wherein the body comprises a debris deflector arranged to deflect the debris. In one embodiment of the first aspect, the debris deflector is movable between a deflecting position in which the debris deflector is extended from the body, and a non-deflecting position in which the debris deflector is retracted into the body.

In one embodiment of the first aspect, the body comprises an actuating means operable to move the debris deflector between the deflecting position and the non-deflecting position.

In one embodiment of the first aspect, the body comprises a first locking means adapted to lock the debris deflector at the deflecting position and the non-deflecting position. In one embodiment of the first aspect, the actuating means comprises a rotatable knob operable for extending and retracting the debris deflector.

In one embodiment of the first aspect, the rotatable knob connects with a gear member adapted to engage a plurality of notches at the debris deflector. In one embodiment of the first aspect, the actuating means comprises a press button operable for extending the debris deflector.

In one embodiment of the first aspect, the debris deflector is retractable manually by applying a pressure on the debris deflector towards the body.

In one embodiment of the first aspect, the first locking means comprises a resilient member.

In one embodiment of the first aspect, the debris deflector is elongated with a planar deflecting surface.

In one embodiment of the first aspect, the debris deflector is arranged to direct an air flow generated by the motor to deflect the debris. In one embodiment of the first aspect, the debris deflector is pivotedly connected with the body.

In one embodiment of the first aspect, the debris deflector comprises a door movable between an air directing position in which the air flow is deflected, and an air non-directing position in which the air flow is not deflected.

In one embodiment of the first aspect, the door is pivotedly movable between the air directing position and the air non-directing position. In one embodiment of the first aspect, the door comprises a sliding plate slidably movable between the air directing position and the air non-directing position.

In one embodiment of the first aspect, the debris deflector comprises a second locking means adapted to lock the door at the air directing position and the air non-directing position.

In one embodiment of the first aspect, the second locking means comprises a resilient member.

In one embodiment of the first aspect, the second locking means comprises a latch mechanism. In one embodiment of the first aspect, the door is movable from the air non-directing position to the air directing position by means of gravitation force.

In one embodiment of the first aspect, the door is movable from the air non-directing position to the air directing position by the air flow generated by the motor. In one embodiment of the first aspect, the air flow is an exhaust gas discharged from the motor.

In one embodiment of the first aspect, the debris deflector is adapted to deflect the air flow in a direction substantially away from an operator of the power tool.

In one embodiment of the first aspect, the debris deflector is adapted to deflect the air flow in a direction substantially transverse to a direction of movement of the operation member. In one embodiment of the first aspect, the power tool is a chainsaw.

In one embodiment of the first aspect, the motor is powered by electricity or gasoline.

In one embodiment of the first aspect, the motor is an AC motor or a DC motor.

In one embodiment of the first aspect, the operation member comprises a saw blade.

In accordance with a second aspect of the present invention, there is provided a debris deflecting device for a power tool comprising: a debris deflector movable between a deflecting position in which the debris deflector is extended from a body of the power tool, and a non-deflecting position in which the debris deflector is retracted into the body.

In one embodiment of the second aspect, the debris deflecting device further comprises an actuating means operable to move the debris deflector between the deflecting position and the non-deflecting position.

In one embodiment of the second aspect, the debris deflecting device further comprises a locking means adapted to lock the debris deflector at the deflecting position and the non- deflecting position.

In one embodiment of the second aspect, the actuating means comprises a rotatable knob operable for extending and retracting the debris deflector.

In one embodiment of the second aspect, the rotatable knob connects with a gear member adapted to engage a plurality of notches at the debris deflector.

In one embodiment of the second aspect, the actuating means comprises a press button operable for extending the debris deflector. In one embodiment of the second aspect, the debris deflector is retractable manually by applying a pressure on the debris deflector towards the body. In one embodiment of the second aspect, the locking means comprises a resilient member.

In one embodiment of the second aspect, the debris deflector is elongated with a planar deflecting surface.

In accordance with a third aspect of the present invention, there is provided a debris deflecting device for a power tool comprising: a debris deflector arranged to direct an air flow generated by a motor of the power tool to deflect debris generated by the power tool.

In one embodiment of the third aspect, the debris deflector is pivotedly connected with a body of the power tool.

In one embodiment of the third aspect, the debris deflector comprises a door movable between an air directing position in which the air flow is deflected, and an air non-directing position in which the air flow is not deflected.

In one embodiment of the third aspect, the door is pivotedly movable between the air directing position and the air non-directing position.

In one embodiment of the third aspect, the door comprises a sliding plate slidably movable between the air directing position and the air non-directing position.

In one embodiment of the third aspect, the debris deflector comprises a locking means adapted to lock the door at the air directing position and the air non-directing position.

In one embodiment of the third aspect, the locking means comprises a resilient member.

In one embodiment of the third aspect, the locking means comprises a latch mechanism.

In one embodiment of the third aspect, the door is movable from the air non-directing position to the air directing position by means of gravitation force.

In one embodiment of the third aspect, the door is movable from the air non-directing position to the air directing position by the air flow generated by the motor.

In one embodiment of the third aspect, the air flow is an exhaust gas discharged from the motor.

In one embodiment of the third aspect, the debris deflector is adapted to deflect the air flow in a direction substantially away from an operator of the power tool. In one embodiment of the third aspect, the debris deflector is adapted to deflect the air flow in a direction substantially transverse to a direction of movement of an operation member of the power tool. In one embodiment of the second and third aspect, the power tool is a chainsaw.

In one embodiment of the third aspect, the motor is powered by electricity or gasoline. In one embodiment of the third aspect, the motor is an AC motor or a DC motor.

In one embodiment of the third aspect, the operation member comprises a saw blade.

Brief Description of the Drawings Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:

Figure 1 is a photographic image showing the discharge of saw dust during the operation of a chainsaw in the prior art;

Figure 2A is a perspective view of a debris deflecting device for a power tool in accordance with a first embodiment of the present invention;

Figure 2B is another perspective view of the debris deflecting device of the first embodiment as shown in Figure 2A;

Figure 3A is a perspective view of a debris deflecting device for a power tool in accordance with a second embodiment of the present invention; Figure 3B is another perspective view of the debris deflecting device of the second embodiment as shown in Figure 3 A;

Figure 4A is a perspective view of a debris deflecting device for a power tool in accordance with a third embodiment of the present invention;

Figure 4B is another perspective view of the debris deflecting device of the third embodiment as shown in Figure 4A;

Figure 5A is a perspective view of a debris deflecting device for a power tool in accordance with a fourth embodiment of the present invention; Figure 5B is another perspective view of the debris deflecting device of the fourth embodiment as shown in Figure 5 A;

Figure 6A is a perspective view of a debris deflecting device for a power tool in accordance with a fifth embodiment of the present invention; and

Figure 6B is another perspective view of the debris deflecting device of the fifth embodiment as shown in Figure 6 A. Figure 7 A is a photographic image showing the deflection path of debris during the operation of a power tool of the present invention when viewed from the front of the power tool.

Figure 7B is a photographic image showing the deflection path of debris during the operation of the power tool of Figure 7A when viewed from the top of the power tool.

Detailed Description of the Preferred Embodiments

The discharge of debris such as saw dust during the operation of a traditional chainsaw is shown in Figure 1. When the moving blade of a chainsaw engages an object to be cut, such as a piece of wood log or a tree trunk, , the generated debris such as saw dusts or wood chips will propel in generally all directions, and particularly, upwardly and outwardly from the cutting site. A significant amount of the propelling saw dusts or chips will be discharged towards the operator or anything near the cutting site which will be messy and inconvenient. In some circumstances, the debris may come with sharp edges or in the form of tiny splinters which may cause irritation or even injury to the operator.

The present invention relates to a power tool, which includes but is not limited to a chainsaw. The power tool comprises a debris deflecting device for deflecting the generated debris from the operator during the operation of the power tool. The power tool includes a body having a motor, such as an electric motor or a gasoline motor. The motor is capable of actuating an operation member, which may include a drive shaft for driving the movement of a saw blade to perform the operation of the chainsaw. The body further comprises a debris deflector arranged to deflect debris generated during the operation of the chainsaw. Figures 2A and 2B show a first embodiment of the present invention. As shown in the figures, the power tool 100 includes a debris deflector 104 movable between a deflecting position 120 in which the debris deflector 104 is extended from the body 102, and a non-deflecting position 122 in which the debris deflector 104 is retracted into the body 102. Preferably, the debris deflector 104 comprises an elongated body 110 with a planar deflecting surface 118 as shown in the figures. Alternatively, the debris deflector can be of other possible configurations such as a bending body with a curved deflecting surface, as long as a person skilled in the art would consider suitable in performing the debris deflecting function.

Preferably, the elongated body 110 includes a portion 124 that is in a length that extends out from the body 102 which is long enough to deflect the debris generated during operation of the power tool 100. Preferably, the length of the potion 124 of the debris deflector 104 that extends out is 25 mm, alternatively, the length of the portion 124 that extends out may be longer than 25 mm for a better debris deflecting performance, or shorter than 25 mm in some other designs such as a simpler debris deflector structure.

In this embodiment, during the operation of the saw chain 100, the debris deflector 104 is arranged to deflect the saw dust generated in a controlled manner by blocking some of the paths that the saw dust may propel. The debris will then be forced to propel in certain direction, for example, the debris deflector may force the debris to propel only along the cutting direction but not towards the operator. Examples of operation will be described below in more details in the later part of this disclosure.

Preferably, the body 102 comprises an actuating means 112 operable to move the debris deflector 104 between the deflecting position 120 and the non-deflecting position 122. In this embodiment, the actuating means comprises a rotatable knob 112 operable for extending or retracting the elongated body 110 of the debris deflector 104, the rotatable knob 112 connects with a gear member 114 adapted to engage a plurality of notches 116 at the debris deflector 120. When a user operates the power tool 100 with the debris deflecting function, the user may rotate the knob 112 in a direction, such that the gear 114 rotates accordingly and move the elongated body 110 of the debris deflector 120 to the deflecting position 120, which is extending out from the body 102 as shown in Figure 2A and Figure 2B. When the user decide to store the power tool 100 or to operate the power tool 100 without the debris deflecting function, the user may rotate the knob 112 in a reversed direction, such that the gear 114 rotates accordingly in a reversed direction and move the elongated body 110 of the debris deflector 104 to the non-deflecting position 122.

Advantageously, accidental damage to the debris deflector 104 may be avoided by retracting and protecting the debris deflector 104 in the body 102 when the power tool 100 is stored or moved.

Referring to Figure 3A and 3B, preferably, the body 202 comprises an actuating means operable to move the debris deflector 204 between the deflecting position 220 and the non- deflecting position 222. In this embodiment, the actuating means comprises a press button 212 operable for extending the debris deflector 204, the debris deflector 204 is retractable manually by applying a pressure on the debris deflector 204 towards the body 202.

Similar to the debris deflector 104, the debris deflector 204 comprises an elongated body 210. The elongated body 210 includes a portion 224 that is in a length that extends out from the body 202 which is long enough to deflect the debris generated during operation of the power tool 200.

When a user operates the power tool 200 with the debris deflecting function, the user may press the button 212 on the body 202, such that the elongated body 210 of the debris deflector 204 move to the deflecting position 220, which is extending out from the body 202 as shown in Figure 3 A and Figure 3B. When the user decides to store the power tool 200 or to operate the power tool 200 without the debris deflecting function, the user may apply a pressure on the elongated body 210 of the debris deflector 204 towards the body 202 and move the debris deflector 204 to the non-deflecting position 222. Optionally, the body 202 may include a first locking means 214 adapted to lock the debris deflector 204 at the deflecting position 220 and the non-deflecting position 222. Preferably, the first locking means 214 comprises a resilient member 216, which is arrange to assist the release and locking of the debris deflector 204. For example, the resilient member 216 may be compressed when the debris deflector 204 is locked in the non-deflecting position 222, whereupon a user press the button 212 on the body 202, the locking means 214 is released and the resilient member 216 is arrange to push the debris deflector 214 out of the body 202.

Similar to the debris deflector 104, accidental damage to the debris deflector 204 may be avoided by retracting and protecting the debris deflector 204 in the body 202 when the power tool 200 is stored or moved.

Preferably, the debris deflector 104 or 204 is elongated with a planar deflecting surface, as shown in Figures 2A, 2B, 3A and 3B. Alternatively the debris deflector is in any other shapes or surfaces such as ruffle surface or bending surface which is operable to perform the debris deflection function.

In some other embodiments, the debris deflector is arranged to direct an air flow generated by the motor to deflect the debris and thus in these embodiments the debris deflector may not necessarily need to make physical contact with the debris, but can, for example, direct air flow to blow away the debris. Preferably, the air flow is an exhaust gas discharged from the motor. Alternatively, the air flow is generated by a fan or discharged from a pipe connected to the source of air flow generated by the motor. In some embodiments, the air flow may be used for cooling the components of the chain saw, especially the motor and the control circuits in the body, the exhaust gas may then be used for blowing the saw dust in certain direction. Preferably, the debris deflector is adapted to deflect the air flow in a direction substantially away from an operator of the power tool. Alternatively, the debris deflector is adapted to deflect the air flow in a direction substantially transverse to a direction of movement of the operation member. Alternatively, the direction of the air flow can be adjusted to any desirable direction which favors the operation of the power tool. Optionally, the debris deflector is movable between the deflecting position and the non-deflecting position such that the debris deflector is not deflecting the debris generated during operation.

Referring to Figure 4A and 4B, preferably, the debris deflector 304 is pivotedly connected with the body 302, and the debris deflector 304 comprises a door 312 movable between an air directing position 320 in which the air flow is deflected, and an air non-directing position 322 in which the air flow is not deflected, and the door 312 is pivotedly movable between the air directing position 320 and the air non-directing position 322. When a user operates the power tool 300 with the debris deflecting function, the user may position the door 312 in an air directing position 320 shown in Figure 4A, such that the debris deflector 304 is arranged to redirect the air generated from the motor, and the redirected air is arrange to direct the debris to a desire direction, which is usually away from the operator of the power tool 300 or transverse to a direction of movement of the operation member of the power tool 300. When the user decides to operate the power tool 300 without the debris deflecting function, the user may position the door 312 in an air non-directing position 322 shown in Figure 4B, and the air flow generated will be discharged without being redirected, and the debris will not be deflected by the debris deflector 304. Advantageously, the operator of the power tool may decide to operate the power tool with or without the debris deflecting function. For example, in some occasion, when another worker is working adjacent to the operator of the power tool, debris deflected to the worker may be dangerous. In that case, the operator of the power tool may choose to disable the debris deflecting function.

Referring to Figure 5 A and 5B, preferably, the debris deflector comprises a door 412 movable between an air directing position 420 in which the air flow is deflected, and an air non- directing position 422 in which the air flow is not deflected, and the door 412 comprises a sliding plate 414 slidably movable between the air directing position 420 and the air non- directing position 422.

When a user operates the power tool 400 with the debris deflecting function, the user may position the sliding plate 414 in an air directing position, such that the door 412 open and the air vents 416 close respectively and the debris deflector 404 is arranged to redirect the air generated from the motor, and the redirected air is arrange to direct the debris to a desire direction, which is usually away from the operator of the power tool 400 or transverse to a direction of movement of the operation member of the power tool 400. When the user decides to operate the power tool 400 without the debris deflecting function, the user may position the sliding plate 414 in an air non-directing position 420 shown in Figure 5B, such that the door 412 close and the air vents 416 open respectively, and the exhaust air is only discharged from the open air vents 416 and is not redirected by the debris deflector 404, thus the debris are not deflected by the debris deflector 404

Optionally, the debris deflector 404 may comprise a second locking means 430 adapted to lock the door at the air directing position 420 and the air non-directing position 422. Preferably, the second locking means 430 may comprise a resilient member 432. Alternatively or additionally, the second locking means 430 comprises a latch mechanism 434.

In yet another embodiment, with reference to Figure 6A and 6B, the debris deflector 504 comprises a door 512, which is movable between an air directing position 520 in which the air flow is deflected, and an air non-directing position 522 in which the air flow is not deflected, and the door 512 is movable from the air non-directing position 522 to the air directing position 520 by means of gravitation force as shown in Figure 6B.

Alternatively, the door 512 is movable from the air non-directing position to the air directing position by the air flow generated by the motor. The door 512 will extend from the body 502 by means of motor discharge wind force, and deflect the wind towards the predetermined direction to blow debris away. The door 512 may be retracted automatically while the power tool 500 is placed on the ground. Optionally, the door 512 may be removed form power tool 500 if the air deflecting function is not needed.

When a user operates the power tool 500 with the air vents 514 on the body 502 which discharge the air flow generated by the motor, the door 512 positioned in an air directing position 520 by gravitation force or the force of the air flow generated by the motor, such that the debris deflector 504 is arranged to redirect the air generated from the motor and discharged from a air vents 514 on the body 502, and the redirected air is arrange to direct the debris to a desire direction, which is usually away from the operator of the power tool 500 or transverse to a direction of movement of the operation member of the power tool 500.

In some embodiments, the debris deflector is removable from the body of the power tool, or may be installed on the chain saw on demand.

In some embodiments, the power tool is a chainsaw. Preferably, the motor of the power tool is powered by electricity, alternatively, the motor is powered by gasoline. Preferably, the motor is an AC motor, alternatively, the motor is a DC motor. Preferably, the operation member of the power tool comprises a saw blade, alternatively, the operation member may comprise other components for other operations on a workpiece, as long as a person skilled in the art would consider suitable in performing operations on a workpiece.

Advantageously, a power tool such as a chainsaw may include one or more debris deflector in accordance with the embodiments of the present invention. The debris deflector in accordance with the first two embodiments enables the operator of a chainsaw to perform cutting operation without discharging the saw dust towards the operator when the operator is holding the chainsaw at a position in front of the operator. The debris deflector in accordance with the last three embodiments further discharge the saw dust away from the operator in a direction transverse to the cutting direction. The debris deflector effectively protects the operator of a chain saw from injured by the debris discharged during operation.

With reference to Figure 7A, there is shown the deflection path of debris 702 during the operation of a power tool 700 of the present invention when viewed from the front of the power tool 700. In this example, the operator 704 of the chain saw 700 cut a piece of wood 706 in a downward direction 708. The debris 702 is deflected towards the left and hence the operator 704 standing on the right is free from debris 702 generated during the cutting operation. As shown in Figure 7B, the deflected debris 702 are mostly discharged to an area 710 from the top to the top left portion of the image, and the operator 704 of the chainsaw 700 is positioned at the bottom right corner which shows that the operator 704 is free from the debris 702 generated.

Without deviating from the spirit of the invention, the power tool can be a chainsaw, a circular saw, a jig saw or any other power tool that may generate saw dust or chips during operation. In some embodiments, the debris deflector can be arranged for deflecting debris other than chips or saw dust. In some other embodiments, a power tool may comprise more than one debris deflectors, or a combination of debris deflectors in accordance with any one of the embodiments of the present invention. It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated.