GB2483151A

GB2483151A - Dust Blower for Chain Saw

Info

Publication number: GB2483151A
Application number: GB1114409.4A
Authority: GB
Inventors: Kirk Worsnop; Keith Park
Original assignee: Chevron HK Ltd
Current assignee: Chevron HK Ltd
Priority date: 2010-08-27
Filing date: 2011-08-22
Publication date: 2012-02-29
Also published as: GB201114409D0

Abstract

A chain saw comprising a motor mounted in a housing and driving a fan and chain sprocket wheel, a guide plate connected to the housing and a chain arranged on the wheel and plate, the saw having an air channel between the fan and the sawing chain. The end 13b of the air channel which is near the chain may extend out of the housing to blow air in a direction tangential to the movement direction of the chain. The end 13a near the fan may be bugle shaped. The channel may be formed by a tubular element 13 or the housing itself. The air blown from the end near the chain may blow into an opening of a dust collecting box or bag 9 mounted on the housing. The air blows sawdust off the chain, improving the efficiency and working life of the saw. The saw may have a hand shield (4, Figure 10) pivotally mounted on the housing between a safety position (Figure 7) and non safety position (Figure 8), a braking mechanism and chain sprocket engaging in the safety position by means of an actuating arm (Figures 16 and 17) to prevent rotation of the sprocket wheel. A lockable chain guard is also disclosed.

Description

CHAIN SAW

FIELD OF THE INVENTION

The present invention relates to a chain saw.

BACKGROUND OF THE INVENTION

For chain saws on the present market, wood dust or other debris is usually clung to a sawing chain during sawing operation. Some dust and debris will be flung off by the inertia force producing during the rotating movement of the sawing chain.

Due to the limit of the inertia force, certain amounts of debris will be still clung to the sawing chain, which obviously on one hand will lead to low efficiency of sawing and on the other hand will affect the working life of the sawing chain.

SUMMARY OF THE INVENTION

A technical problem to be solved in the present invention is to provide a chain saw which can enhance the sawing efficiency and elongate the working life of the sawing chain.

To solve the above mentioned tecimical problem, the chain saw according to the present invention comprises a housing, a motor mounted in the housing, a fan driven by the motor, a chain sprocket wheel driven by the motor, a guide plate mounted on the housing and a sawing chain arranged on the chain sprocket wheel and the guide plate, wherein the chain saw has a air channel with a first end is near the fan and a second end is near the sawing chain.

By adopting the chain saw with the air channel mechanism according to the present invention, the sawing efficiency can be enhanced and elongate the working life of the sawing chain can also be extended.

DESCRIPTION OF THE DRAWINGS

Other features and advantageous of the present invention will be described more clearly by referring to the accompanying drawings and the embodiments below.

Fig. 1 is a perspective view of a chain saw of a preferred embodiment according to the invention, wherein a housing is partially removed.

Fig. 2 is a perspective view of the chain saw of the preferred embodiment according to the invention for showing the arrangement of a dust exhausting case.

Fig. 3 is a perspective view of the chain saw of the preferred embodiment according to the invention for showing a part of a dust-blowing mechanism located in the housing.

Fig. 4 is a perspective view of the chain saw of the preferred embodiment 0 according to the invention for showing a part of the dust-blowing mechanism located out of the housing.

Fig. 5 is a schematic view of the chain saw of the preferred embodiment according to the invention for showing a direction of the dust-blowing flow outside of an outlet of the dust-blowing mechanism.

Fig. 6 is a schematic view of the chain saw of the preferred embodiment of according to the invention for showing a direction of the dust-blowing flow inside of the dust-blowing mechanism.

Fig. 7 is a schematic view showing an embodiment of a safety indicator mechanism of the chain saw according to the invention, wherein the safety indicator mechanism is located at a safety position.

Fig. 8 is a schematic view showing the safety indicator mechanism of the chain saw in Fig. 7 which is located at a non-safety position.

Fig. 9 is an assembly view of an alerting indicator arm of the safety indicator mechanism of the chain saw in Fig. 7.

Fig. 10 is a perspective view showing the assembly relationship between the safety indicator mechanism in Fig. 7 and a hand shield.

Fig. 11 is a perspective view showing the chain guard of the chain saw according to the invention is located at a released position.

Fig. 12 is a perspective view showing the chain guard of the chain saw according to the invention is located at a locked position.

Fig. 13 is a perspective view showing the assembly relationship between a locking device of the sawing chain guard and the safety indicator mechanism of the chain saw according to the invention.

Fig. 14 is a perspective view showing a safety shield of the chain saw according to the invention.

Fig. 15 is a schematic view showing a sawing indicator zone of a guide plate of the chain saw according tothe invention.

Fig. 16 is a perspective view showing that a braking mechanism engages with the chain sprocket wheel of the chain saw according to the invention.

Fig. 17 is a perspective view showing that the braking mechanism engages with the chain sprocket wheel of the chain saw of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in Figs. 1-3 and 16, a chain saw of a preferred embodiment according to the present invention comprises a housing 2, a rear handle 1 connected to a rear end of the housing 2, a front handle 6 fixedly mounted to the housing 2 and near a front end of the housing 2, and a hand shield 4 preferably pivotally mounted to the front end of the housing 2. The housing 2 forms a longitudinal axis X extending in a direction from the front handle to the rear handle. The chain saw also comprises a motor 3, which has a motor spindle (not shown), mounted in the housing 2.

Preferably, an axis Y is perpendicular to the axis X. A chain sprocket wheel 10 is mounted on an output spindle 34 which extends along the axis Y, and the chain sprocket wheel 10 is driven to rotate by the motor 3 through a transmission mechanism connecting the output spindle 34 to the motor spindle. The transmission mechanism could be a planetary gears transmission mechanism or other reduction gears transmission mechanism. Along the longitudinal axis X, a guide plate 5 is arranged in front of the chain sprocket wheel 10 and fixed on the housing 2 by a chain cover 7 and a nut 8. A sawing chain 11 is mounted on the periphery of the chain sprocket wheel 10 and the guide plate 5, so as to be moved driven by the chain sprocket wheel along the movement path Z around the periphery of the chain sprocket wheel and the guide plate. The above structures are well known by those skilled in the art and will not be described in details herein.

As shown in Figs. 3-6, a fan 12 of the chain saw of the preferred embodiment according to the invention is mounted to the motor spindle (not shown) and driven to be rotated by the motor spindle. An annular passage W is formed between a circumference of the fan 12 and the inner surface of the housing 2. The chain saw according to the invention has an air channel, which is mainly composed of the inner cavity of a tubular element 13 in the preferred embodiment. The tubular element 13 can be connected to the housing 2 by any well-known fixation means, such as screw or clasp or the like, which will not be described in details herein, The tubular element 13 has a first end 13a and a second end 13b. The first end 13a extends into the housing 2, and is communicated with the annular passage W so that the air flow formed by the fan can flow along the air channel in the tubular element. Preferably, the first end 13a of the tubular element is near the fan. .A opening 14 is formed on the 1 0 housing 2 and preferably below the sawing chain 11. Alternatively, the opening 14 also can be formed abovethe sawing chain 11. The second end 13b of the tubular element extends into the opening 14 and lies below the sawing chain. The second end 1 3b of the tubular element 13 preferably passes through the opening 14 on the housing 2 so that the air blown out from the second end 1 3b will be nearer a certain point of the sawing chain. In order to further enhance the dust-blowing efficiency, the second end 13b of the tubular element 13 is bent to make the direction of the flow blown out from the second end conform to a tangential direction of the movement path Z of the sawing chain. In order to introduce more air flow into the tubular element 13, preferably, the first end 13 a is bugle-shaped. When the motor 3 is switched on, the motor 3 drives the fan 12 to rotate. An air flow is formed in the annular passage W by the rotation of the fan 12 and at least a portion of the air flow enters into the first end 1 3a of the tubular element 13 to move along the arrows in the figures, and is blown out from the second end l3b of the tubular element to the sawing chain 11. The dust or other debris on the sawing chain 11 will be away from the sawing chain 11 under the action of its own inertia and the blowing of the air flow.

In other embodiments, a part or all of the air passage could also be constructed of an element or elements of the housing, for example, an element or elements inside the housing forms a part of the air channel in the housing, otherwise a tubular element arranged on the housing forms another part of the air passage, etc. Of course, other structures are also possible. Additionally, the housing is also arranged with a dust collecting box 9, which can be mounted on the housing 2 by screw or other appropriate manners, The dust collecting box 9, which is located below the sawing chain 11, is preferably composed of two parts 9a and 9b, and has an opening 9c. The air flow blown out from the second end 13b is blown to the opening 9c of the dust collecting box 9, so that the dust or other debris blown away from the sawing chain 11 can enter the opening 9c of the dust collecting box 9 and be exhausted. In addition, the dust collecting box 9 can be formed from a part or more parts and the dust collecting box 9 can be replaced by a collection bag. The collecting bag is mounted on the housing and an opening is formed on the collecting bag, the air blown out from the second end of the air channel is blown to the opening.

Figs. 7-10 show an embodiment of the safety indicator mechanism of the chain saw according to the invention. As shown in Fig. 10, the hand shield 4 pivotally mounted on the front end of the housing 2 comprises a holding portion 4a and a pivoting portion 4b. The pivoting portion 4b has a pivoting axis 0 parallel to the axis Y and perpendicular to the longitudinal axis X, and comprises a fixation portion 4e and a protruding portion. The protruding portion omprises a main portion 4c and an indicator arm 4d. The indicator arm 4d comprises a body part 4d1 being of a hollow cylinder by which the indicator arm 4d can be press assembled to the main portion 4c, and a safety indicator part 4d2 being of U shape and forming a space.

Additionally, the indicator arm 4d can also be assembled to the main portion 4c by other well-known manners, such as soldering, plugging or the like. Of course, the indicator arm 4d can also be formed with the main portion 4c integrally. As shown in Figs. 1, 7 and 8, the hand shield 4 is arranged to the housing 2 by the fixation portion 4e of the pivoting portion 4b, and the protruding portion is located in the housing. The hand shield 4 can pivotally move relative to the housing 2 between a safety position shown in Fig. 7 and a non-safety position shown in Fig. 8. The chain saw according to the present invention comprises a braking mechanism actuated by the movement of the hand shield 4. When the hand shield 4 is rotated to a first position (the safety position) about the pivoting axis 0 (as shown in Fig. 7), the braking mechanism and the chain sprocket wheel engage with each other so that the sprocket wheel work 10 can't be driven to rotate by the output spindle. When the hand shield 4 is rotated to a second position (the non-safety position) about the pivoting axis 0 (as shown in Fig. 8), the braking mechanism and the chain sprocket wheel 10 depart from each other so that the chain sprocket wheel can move with the output spindle under the driving of the motor. Figs. 16 and 17 show an embodiment of the braking mechanism, which comprises an actuating arm 30 and a braking arm 31.

One end of the actuating arm 30 is fixedly mounted on the main portion 4c, and the other end has an arc portion 30a. A mounting hole 31b is arranged on the braking arm 31, by which the braking arm 31 can be mounted on the rotating spindle 32 which is fixedly mounted on the housing. A return spring 33 is arranged between the braking arm 31 and the housing so that the braking arm 31 can be rotated about the rotating spindle 32 under the action of the return spring 33 when no external force acts thereon. The braking arm 31 also comprises a receiving slot 31 a, an inclined surface 31c and a braking tooth 31d. The arc portion 30a of the actuating arm 30 can engage with the receiving slot 3 la. A braking gear 35 is mounted on the output spindle 34 and slidable along the axis Y. A spring 36 (not shown in Figs. 16 and 17) is arranged between the braking gear 35 and the chain sprocket wheel 10. The braking gear 35 comprises a braking tooth 35a and a clutching tooth 35b. The transmission mechanism also comprises a gear 37 which comprises a clutching tooth 37a that could be engaged with the clutching tooth 35b. When the hand shield 4 is moved forward and into the first position, the arc portion 30a of the actuating arm 30 is actuated by the main portion 4c to depart from the receiving slot 31 a of the braking arm 31 so that the braking arm 3 1 can be rotated under the action of the spring 33 and the inclined surface 31c of the braking arm 31 overcomes the elastic force of the spring 36 and urges the braking gear 35 to slide toward the chain sprocket wheel 10, and finally the clutching teeth 35b and 37a are detached and meanwhile the braking tooth 31d of the braking arm 31 is engaged with the braking tooth 35a. At this time, even if the motor is started to rotate, it won't drive the chain sprocket wheel to rotate, and thereby the tool is in a safe state. When the hand shield 4 is pushed to the sQcond position by the operator, the arc portion 30a of the actuating arm 30 enters the receiving slot 31a of the braking arm 31 under the driving of the main portion 4c, and the restoring force of the spring 33 urges the braking arm 31 to rotate about the rotating spindle 32 till the inclined surface 31c of the braking arm 31 releases the braking gear 35 so that the braking gear 35 will be away from the chain sprocket well 10 under the restoring force of the spring 36 and slide along the axis Y till the clutching tooth 35b is engaged with th clutching tooth 37a, and the braking tooth 31 d of the braking arm 31 departs from the braking tooth 35a. At this time, the tool is in a workable state, i.e. a non-safety state. The housing has an observing opening 1 8a in the position corresponding to the safety indicator part 4d2 of the indicator arm 4d. As shown in Fig. 7, when the hand shield 4 is in the first position, the tool is in the safety state.

The safety indicator part 4d2 of the indicator arm 4d is aligned with the observing opening 1 8a through which the operator may observe the safety indicator part 4d2, so that the safety indicator part 4d2 could indicate to the operator that the tool is in the safety state. Furthermore, the safety indicator part 4c12 preferably includes words or pictures of safety indicator, such as "SAFE" or other similar words, which could give the operator a more direct indication. The observing opening could be a through hole or a transparent portion. Additionally, to prevent the debris such as dust from entering the tool, the observing opening 1 8a is preferably arranged with detachable transparent device. The transparent device can be composed of transparent plastic or other transparent materials. As shown in Fig. 8, when the hand shield 4 is in the shown second position, the tool is in the non-safety state. The position of the safety indicator part 4d2 of the indicator arm 4d isn't aligned with the observing opening 1 8a formed on the housing, so that the operator cannot observe the safety indicator part 4d2 of the safety indicator arm 4d. As shown in Fig. 9, to better achieve the indication to the operator in the non-safety state, a mounting bracket 17 for the alerting indicator arm is arranged in the housing 2 near the observing opening 1 8a.

The alerting indicator arm 16 is fixed to the mounting bracket 17, so that the alerting indicator arm 16 is located below the observing opening 1 8a and is aligned with it.

When the hand shield 4 is located in the first position, the safety indicator part 4d2 of the indicator arm 4d is positioned between the observing opening 1 8a and the alerting indicator arm 16, i.e. covering the alerting indicator arm 16. It's best that the alerting indicator arm 16 is located in the space between the two arms of the U shape safety indicator part of the safety indicator arm and the operator may observe the safety indicator part 4d2. When the hand shield 4 is in the second position, the safety indicator part 4d2 of the indicator arm 4d departs from the alerting indicator arm 16, i.e. isn't aligned with the observing opening 1 8a, and the operator may observe the alerting indicator arm 16, so as to be indicated that the tool is in the non-safety state now. Similarly, the alerting indicator arm 16 can comprise an alerting indicator portion having alerting indicator words or pictures. According to the above structure, safety can be improved.

Figs. 11-13 show a locking mechanism of the chain guard of the present invention. The protruding portion of the hand shield 4 of the chain saw of the invention further comprises a locking portion 19. As shown, the locking portion 19 is integrally formed with the main portion 4c of the protruding portion. Of course, it may also be connected to the main portion 4c of the protruding portion by thread or other suitable manners. A sawing chain cover7 is mounted to the housing 2 by the nut 8. The sawing chain cover 7 includes an upper cover plate 7a on which a cooperating portion is formed. Herein the cooperating portion is an L shape through slot 20, which comprises a lateral slot 20a along the direction parallel to the extending direction of the longitudinal axis X and a longitudinal slot 20b perpendicular to the extending direction of the longitudinal axis X and extending toward the housing.

The locking portion 19 comprises a locking main portion 19a and a locking pin 19b.

The main portion 19a is preferable to be of cylinder shape. The locking pin 19b is mounted to the main portion 19a and extends out along the radial direction of the main portion 1 9a. Moreover, the locking portion 19 can only include the locking pin 1 9b and the locking pin 1 9b is directly mounted to or formed on the main portion 4c of the protruding portion. As shown in Figs. 11 and 12, the locking portion 19 extends out of the housing 2 and the locking pin 1 9b extends into the L shape slot of the chain cover 7. When the hand shield 4 is located in the first position, as shown in Fig. 11, the locking pin 19b is located in the longitudinal slot 20b of the L-shape through slot 20, and the locking pill 1 9b departs from the L-shape through slot 20.

At this time, the operator can remove the sawing chain cover 7 by rotating the nut 8.

When the, hand shield. 4 is rotated into the second position, the locking pin 1 9b is rotated about the pivoting axis 0 into the lateral slot 20b of the L-shape through slot 20, and the locking pin 19b is engaged with the L-shape through slot 20. At this time, the operator will be prevented from removing the sawing chain cover 7.

Therefore, when the tool is in the non-safety state, it could prevent the operator from detaching the sawing chain cover 7 by accident, thereby preventing the sawing chain accidentally wounding the operator. Moreover, the locking portion can also be directly mounted to the holding portion 4b of the hand shield 4. The locking pin on the locking portion can also be replaced by an L-shape slot and the L-shape slot on the sawing chain cover 7 can be replaced by a locking pin, etc. According to the above structure, safety can be improved.

Fig. 14 shows the safety guard mechanism of the invention. The guide plate 5 has a front end and a rear end. The rear end of the guide plate 5 is located in front of the chain sprocket wheel 10, and the guide plate 5 is fixedly mounted on the housing 2 by the nut 8 and the sawing chain cover 7. A top guard 21 comprises a connecting portion 21a and a shielding portion 21b. The top guard 21 is fixedly mounted to the guide plate 5 by fixing the connecting portion 21a of the top guard 21 to the front end of the guide plate 5. The shielding portion 21 b of the top guard 21 may cover the front end of the sawing chain 11, so as to prevent the operator from touching the front end portion of the sawing chain 11. A plate-shaped guard 22 comprises a connecting portion 22a and a shielding portion 22b. The connecting portion 22a is formed with an elongated slot 23 on its rear end. A screw 24 passes through the elongated slot 23 and fixes the plate-shape guard 22 on the housing 2. The plate-shaped guard 22 is located above the guide plate 5, so that the shielding portion 22b of the plate-shaped guard 22 may cover the exposed portion of the chain on the guide plate 5, thereby preventing the operator from touching the sawing chain 11 when the tool is rebounded.

In addition, to better support the plate-shape guard 22, the front end of the connecting portion 22a can also be fixed to the top guard 21 by the fixing method similar to that of the rear end. By the elongated slot 23, the operator can move the guiding plate 5 along the longitudinal axis X, thereby achieving the tension adjustment of the chain.

According to the above structure, safety can be improved.

Fig. 14 shows an embodiment of the sawing indicator zone of the guide plate of the chain saw according to the present invention. The motor 3 of the chain saw of the invention drives the sawing chain 11 to rotate around the periphery of the guide plate 5, so as to cut the working element below the guide plate 5. In order to indicate that a sawing zone is below the guide plate 5 so as to remind the operator of safety, a sawing indicator zone 5a is formed in the portion of the guide plate 5 near the working zone. The sawing indicator zone 5a can be marked with words, such as "cut-zone" or "sawing zone" and other words, or practical figures, such as hatching.

It may also be indicated by colorful paints for the sawing indicator zone. According to the above structure, safety can be improved.

The above description and the accompanying drawings are only several preferred embodiments of the present invention, the protection range should be defined by the appended claims, According to the above description and the drawings, those skilled in the art could make substitution for some of the elements by the same method or simple replacement without any inventiveness, which will be also deemed to be included in the protection range of the invention.

Claims

What's claimed is: 1. A chain saw, comprising: a housing, a motor mounted in the housing, a fan driven by the motor, a chain sprocket wheel driven by the motor, a guide plate connected to the housing and a sawing chain arranged on the chain sprocket wheel and the guide plate, wherein the chain saw has a air channel with a first end near the fan and a second end near the sawing chain.
2. The chain saw according to Claim 1, wherein the second end of the air channel is located below or above the sawing chain.
3. The chain saw according to Claim 1 or 2, wherein the second end of the air channel extends out of the housing.
4. The chain saw according to Claim 3, wherein a direction of the air blown out from the second end of the air channel conforms to a tangential direction of movement path of the sawing chain.
5. The chain saw according to Claim 1, wherein an annular passage is formed between the housing and the fan, and the first end of the air channel extends into the annular passage.
6. The chain saw according to Claim 1 or 5, wherein the first end of the air channel is of bugle-shape.
7. The chain saw according to any one of Claims 1,2 and 4, wherein a dust collecting box is mounted on the housing and an opening is formed on the dust collecting box, the air blown out from the second end of the air channel is blown to the opening.
8. The chain saw according to any one of Claims 1,2 and 4, wherein a collecting bag is mounted on the housing and an opening is formed on the collecting bag, the air blown out from the second end of the air channel is blown to the opening.