JP2007032606A - Braking device for chain saw, and chain saw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a braking device for a chain saw capable of positively stopping a chain when the chain saw is changed from a driven state to a non-driven state. <P>SOLUTION: In the braking device 30 of the chain saw, when there is impact, locking of a front end 321 of a belt 32 to a body by a locking member 35 is released, an oblong hole 371 for a protrusion is locked to the protrusion 119 when the front end 321 is drawn by spring force of a compressed coil spring 33, and since following of a rear end 322 of an opposite side of the drawn side to movement of the front end 321 is regulated, powerful winding up of a drum 31 by the belt 32 becomes possible. By this, since the chain 20 can be positively stopped, breakage of the chain 20 such as when the chain saw 1 is dropped due to impact can be prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a brake device for stopping a chain of a chain saw, and a chain saw provided with the brake device.

  2. Description of the Related Art Conventionally, a chain saw that has an endless chain (saw chain) with a saw blade when a tree or bamboo is cut and pruned and the chain is driven to rotate by lever operation has been used.

  Such a chain saw has a built-in brake device for stopping the chain drive and preventing the chain from being damaged when it is dropped or hit against a tree, for example. The one end side of the belt wound around the drum provided on the rotating shaft of the chain is pulled by the urging force of the spring, so that the rotating drum is wound and stopped by the belt.

By the way, although the chain is driven by an engine or an electric motor via a centrifugal clutch, the chain does not stop immediately even when the centrifugal clutch is broken by returning the operation lever. For this reason, in the chain saw of the electric motor drive system, when the operation lever is returned, the rotation of the chain is mechanically stopped by pulling the other end side of the belt wound around the drum of the brake device described above. There is an example in which a brake device is provided (for example, Patent Document 1).
Japanese Patent No. 3263284 (paragraphs “0024” to “0027”, FIG. 3)

  However, as in Patent Document 1, when both ends of the belt wound around the drum are pulled to form separate brake mechanisms, when either one is pulled, the opposite side follows and the belt loosens. There is a possibility of moving in the direction, and there is anxiety about braking of the brake.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a chain saw brake device capable of reliably stopping a chain when the drive state is changed to the non-drive state, and a chain saw provided with the brake device.

  A chain saw brake device according to a first aspect of the present invention includes a main body on which an engine is mounted and a chain on which a saw blade is provided, and the chain is driven by an engine around a guide member provided on the main body. A chain saw brake device for stopping the chain, the drum being provided on a rotating shaft of a sprocket that transmits the driving force of the engine to the chain and rotating together with the sprocket, and the drum And a first urging means and a second urging means for urging both ends of the belt in opposite directions in the direction in which the drum is wound and tightened, respectively. And a locking member for locking the belt to the main body so as to resist the biasing force of the first biasing means. A restriction that restricts movement of the other end side of the belt to a certain range following the movement of the one end side when the one end side of the belt moves by the urging force of the first urging means. Means are provided.

  In the chain saw brake device according to a second aspect of the present invention, the belt has an attachment portion to which the second urging means is attached, and the attachment portion extends along a longitudinal direction of the belt. A long hole is formed, and the restricting means is a protrusion inserted through the long hole.

  In the chain saw brake device according to a third aspect of the present invention, the second biasing means is a coil spring, and one end side of the coil spring is attached to the other end side of the belt, and the coil spring The other end side is attached to a female screw member formed with a female screw, and the male screw member is attached to the main body and a male screw member formed with a male screw is screwed to the female screw member. The female screw member is characterized in that it can advance and retreat along the biasing direction of the coil spring.

  In the chain saw brake device according to a fourth aspect of the present invention, the main body includes a throttle lever for adjusting the output of the engine and a direction in which the throttle lever resists the urging force of the second urging means. A stopper is provided that engages with an end face on the other end side of the belt in a rotated state.

  According to a fifth aspect of the present invention, there is provided a chain saw including the aforementioned chain saw brake device.

  According to the chain saw brake device of the first aspect, when the belt is pulled by the urging force of the first urging means, the side opposite to the pulled side of the belt follows and moves in the same direction. Since this is regulated within a certain range by the regulating means, the drum can be strongly wound with the belt, and the chain can be surely stopped as the drum and the sprocket stop rotating.

  In other words, when the tip of the guide member is cut or the tip hits an obstacle and the chainsaw is bounced upward (kickback), a certain external force is applied to the chain saw and a large external force acts on the locking member. When the belt is unlocked by the member and one end side of the belt is pulled, the drum is strongly wound and tightened by the belt, and the chain is stopped reliably and quickly. Thereby, it is possible to prevent the chain from being damaged at the time of impact.

  According to the chain saw brake device of the first aspect, when the throttle lever is released, the end of the belt is pulled by the urging force of the second urging means, so that the drum is wound with the belt. As the drum and sprocket stop rotating, the chain can be stopped. That is, when the throttle lever is released, the rotation of the chain can be stopped in a short time without the chain continuing to rotate due to its inertial force.

  According to the chain saw brake device of the second aspect of the present invention, it is possible to make a simple structure in which the movement of the belt is restricted only by locking the elongated hole in the protrusion, and the protrusion is fixed to the main body or the case. Since the movement of the belt not only in the direction along the long axis direction of the long hole but also in the direction intersecting with the long axis direction is restricted, the belt moves in the width direction on the outer peripheral surface of the drum when the belt moves. The chain can be stably stopped without shifting.

  According to the chain saw brake device of the third aspect, when the male screw member is rotated and the female screw member is advanced and retracted, the extension amount of the coil spring, that is, the urging force is changed, whereby the belt is tightened around the drum. Since the tightening force also changes, the time for the chain to stop can be adjusted. By adjusting the braking time until the chain stops, it is possible to use it, for example, by removing the branches with the remaining power of the chain rotation, improving handling according to the target of logging and the operator's feeling of operation. Can be made.

  According to the chain saw brake device of the fourth aspect of the present invention, the movement of the belt due to the second urging force is restricted by pushing the stopper while the throttle lever is rotated to engage the end surface of the belt. Even when the throttle lever is returned, the brake mechanism by the second urging force can be maintained in a non-operating state. By using the stopper in this way, a brake mechanism using the second urging force may be used according to the purpose of the work, and the handleability can be improved.

  According to the chain saw of the fifth aspect, since the brake device as described above is provided, the same operation and effect as described above can be enjoyed.

[First Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.

  FIG. 1 is a schematic view of a chainsaw 1 in the present embodiment.

  The chain saw 1 drives a chain 20 wound around a guide member (not shown) projecting forward from a body 11 covered with a synthetic resin case by an engine (not shown). It is used by gripping the extending bar-shaped handle 111. The handle 111 is held by one hand of the operator. The chain saw 1 is also provided with another handle that is held by the other hand, but the illustration thereof is omitted here.

  The grip portion of the handle 111 is provided with a throttle lever 131 that adjusts the amount of intake air to the engine together with the spring 131A. When the handle 111 is gripped, the throttle lever 131 rotates about the shaft portion 131B to grip the handle 111. When the hand is loosened, the throttle lever 131 is biased by the spring 131A and returns to its original position. A carburetor 200 is connected to the throttle lever 131.

  In addition, a hand guard (not shown) for protecting the operator's hand from the rotating chain 20 is provided in front of the handle 111.

  An engine is stored inside the main body 11, and a sprocket 132 is provided on the output shaft of the engine.

  The chain 20 is an endless saw chain provided with a saw blade. The chain 20 is wound around the guide member and the sprocket 132 and is rotated by the driving force of the engine transmitted to the sprocket 132.

  Here, the rotating shaft 132 </ b> A of the sprocket 132 is provided with a drum 31 that incorporates a centrifugal clutch and rotates together with the sprocket 132.

  A metal belt 32 is wound around the outer peripheral portion 311 of the drum 31, and the front end portion 321 and the rear end portion 322 of the belt 32 are each drawn out to the opposite side. By tightening the drum 31 with such a belt 32, it is possible to stop the rotation of the drum 31 and the sprocket 132 and stop the driving of the chain 20, and the brake device including the belt 32 and the drum 31 is included. 30 is configured.

  FIG. 2 is a perspective view of the brake device 30.

  The brake device 30 includes a first biasing unit that biases the front end 321 and the rear end 322 of the belt 32 in opposite directions in addition to the drum 31 (two-dot chain line in FIG. 2) and the belt 32. A strong compression coil spring 33, a tension coil spring 34 as a second biasing means, and a locking member 35 for locking the front end 321 of the belt 32 to the main body 11 (FIG. 1). Has been.

  The width of the belt 32 is narrower than the width dimension of the outer peripheral portion 311, and the front end portion 321 side and the rear end portion 322 side intersect at an intersecting portion 323 intersected on the outer peripheral portion 311 of the drum 31.

  Further, the front end 321 side of the belt 32 is wider than the crossing portion 323, and the widened portion is a front mounting portion 36 in which a hole 361 through which the locking member 35 is inserted is formed.

  A chain (kickback) brake mechanism that operates in the event of an impact such as kickback is configured including the front mounting portion 36, the locking member 35, and the compression coil spring 33.

  The locking member 35 includes a first member 351 on the front attachment portion 36 side, and a second member 352 connected to the first member 351 by a link 353.

  The first member 351 has a pin portion 351A inserted through the hole 361, a protrusion 351B protruding upward, and a rod-shaped portion 351C through which the compression coil spring 33 is inserted, and is a spring configured as a part of the main body 11 The compression coil spring 33 is arranged in a compressed state between the stopper portion 115 and the base end portion of the rod-shaped portion 351C.

  The second member 352 includes a protrusion 352B that faces the protrusion 351B of the first member 351, and an inclined portion 352C that gradually separates from the first member 351 as it goes down from the protrusion 352B. The protrusion 352B and the inclined portion An end 352D opposite to the side on which 352C is formed is rotatably attached to the main body 11.

  The link 353 has two rotating shafts 353A and 353B at both ends, and the first member 351 and the second member 352 are rotatably connected by the rotating shafts 353A and 353B, respectively.

  Here, the first member 351 is biased toward the second member 352 by the spring force of the compression coil spring 33, but the link 353 is stretched between the first member 351 and the second member 352. The second member 352 is separated. At this time, as shown in FIG. 2, the first member 351 and the second member 352 are in a state in which the rotation shafts 353 </ b> A and 353 </ b> B of the link 353 are aligned along the direction facing each other.

  On the other hand, the rear end portion 322 side of the belt 23 from the crossing portion 323 also has a rear mounting portion 37 widened in the same manner as the front end portion 321, and includes the rear mounting portion 37 and the tension coil spring 34. A throttle brake mechanism that operates when the lever 131 is returned is configured.

  The rear attachment portion 37 is formed relatively long along the longitudinal direction of the belt 32. The rear mounting portion 37 is formed with a projection long hole 371 and a lever long hole 372 along the longitudinal direction thereof, and a tension coil spring 34 is attached to the end of the rear mounting portion 37. ing.

  The tension coil spring 34 has hooks 34 </ b> A at both ends, one hook 34 </ b> A is hooked in the hole 373 of the rear mounting portion 37, and the other hook 34 </ b> A is locked to a spring stopper 118 provided in the main body 11. .

  A protrusion 119 as a restricting means fixed to the main body 11 is inserted through the protrusion long hole 371.

  An internal lever 135 that is interlocked with the throttle lever 131 is inserted into the lever long hole 372. As shown in FIG. 1, the internal lever 135 is connected to the throttle lever 131 by a wire 136 routed by a guide roller 136 A inside the handle 111, and the movement of the throttle lever 131 is moved through the rear mounting portion 37 to the belt 32. To communicate. Specifically, the internal lever 135 is provided in the main body 11 so as to be rotatable about the rotation shaft 135A. When the throttle lever 131 is rotated in the ON direction, the internal lever 135 is rotated via the wire 136 and is attached to the rear side. The part 37 is moved in a direction against the spring force of the tension coil spring 34.

  The operation of the brake device 30 described above will be described with reference to FIGS.

  3 and 4 show a driving state and a driving stop state in normal use of the chainsaw 1.

  FIG. 3 shows a state in which the chain 20 is driven by the ON operation of the throttle lever 131 (FIG. 1). At this time, the internal lever 135 rotates in conjunction with the operation of the throttle lever 131, and the rear mounting is performed. When the end portion 372 </ b> A of the lever long hole 372 is pressed in the portion 37, the rear mounting portion 37 moves in a direction against the spring force of the tension coil spring 34. By the rotation of the internal lever 135, the rear end portion 322 of the belt 32 moves to the drum 31 side and the belt 32 is loosened on the outer peripheral portion 311 of the drum 31, so that the rotation of the drum 31 is not regulated by the belt 32. The throttle brake mechanism of the brake device 30 is released.

  When the throttle lever 131 is returned in this state, the centrifugal clutch is disengaged as the engine speed decreases, and transmission of the engine driving force to the sprocket 132 is stopped. At the same time, as shown in FIG. The rear end 322 of the belt 32 is pulled rearward by the spring force of 34, and the drum 31 is wound up by the belt 32. At this time, there is a gap SP1 between the protrusion 119 and the end 371A of the protrusion long hole 371, and the rear mounting portion 37 is held by the spring force of the tension coil spring 34. By such braking of the throttle brake mechanism in the brake device 30, the rotation of the drum 31 is quickly stopped, and the driving of the chain 20 is also quickly stopped.

  Next, FIGS. 5 and 6 show the braking of the brake device 30 when some kind of impact is applied to the chainsaw 1.

  FIG. 5 shows a state in which an impact is applied while the throttle lever 131 is being held. Due to the external force at the time of the impact, the second member 352 of the locking member 35 rotates upward. Then, the link 353 is inclined obliquely, and as a result, the first member 351 and the second member 352 are close to each other, and the compression coil spring 33 is slightly restored. As the compression spring 33 is restored, the front end portion 321 of the belt 32 is pulled, and the rear end portion 322 of the belt 32 follows the pulling of the front end portion 321, but the end portion 371 </ b> B of the projection long hole 371 follows the projection 119. Since it is locked, the rear end 322 does not follow any further, and the drum 31 is tightly wound by the belt 32, so that the chain 20 stops reliably and quickly.

  6 shows a state in which the hand is released from the throttle lever 131 in FIG. 5. At this time, the internal lever 135 rotates along the lever long hole 372, and the tension coil spring 34, the drum 31 and the carburetor. The original position is restored by the bias of the spring 200.

  3 and 4 showing normal braking by the throttle brake mechanism of the brake device 30, and FIG. 5 and FIG. 6 showing braking by the chain brake mechanism when subjected to an impact, The belt 32 is quickly moved by the spring force of the compression coil spring 33 or the tension coil spring 34. However, since the protrusion 119 is inserted into the protrusion long hole 371 of the rear mounting portion 37, the belt 32 has a protrusion long hole 371. The chain 20 is stably and reliably stopped because there is no fear of shifting in the width direction at the outer peripheral portion 311 of the drum 31.

According to the present embodiment, the following effects can be obtained.
(1) According to the brake device 30 of the chain saw 1, when the chain brake mechanism operates at the time of impact and the front end 321 of the belt 32 is pulled by the spring force of the compression coil spring 33, Since the long hole 371 is locked to the protrusion 119, the rear end 322 can be restricted from moving in the same direction following the pulling of the front end 321 and the throttle brake mechanism having the tension coil spring 34 can be controlled. Even when the drum 31 is provided, the drum 31 can be strongly wound with the belt 32. As a result, the chain 20 can be stopped reliably, so that when a shock is applied to the chain saw 1, the chain brake mechanism can be reliably functioned and the chain 20 can be stopped immediately.
(2) Here, simply by locking the protrusion long hole 371 of the rear mounting portion 37 to the protrusion 119, the movement of the rear end 322 of the belt 32 is restricted by the end 371B of the protrusion long hole 371. Since the protrusion can be structured and the protrusion is fixed to the main body or the case, it is possible to restrict the movement of the belt 32 in the direction intersecting the long axis direction of the protrusion long hole 371. The chain 20 can be stably stopped without moving in the width direction on the outer peripheral portion 311 of the drum 31 when moving.
[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.

  The difference between the brake device 40 in the present embodiment and the brake device 30 in the first embodiment is mainly that the tension coil spring 34 that biases the rear end 322 of the belt 32 in the brake device 40 in the present embodiment. This is because the spring force is configured to be adjustable and a stopper 375 for locking the rear end 322 of the belt 32 is added. Further, the chain saw of this embodiment is not provided with the internal lever 135 as in the first embodiment. Thus, the rear mounting portion 47 constituting the rear end portion 322 of the belt 32 is not formed with a long hole for inserting the internal lever 135, and the rear mounting portion 47 and the throttle lever 137 are directly connected by the wire 136. It is connected.

  In the brake device 40 shown in FIG. 7, in this embodiment, the spring stopper 118 of the tension coil spring 34 is formed so as to protrude from a piece member 341 slidably accommodated in a bracket (not shown). A female thread is formed in the member 341 so as to penetrate along the expansion / contraction direction of the tension coil spring 34. A male screw member 342 in which a male screw is engraved is screwed into the female screw. By rotating the male screw member 342, the piece member 341 and the spring stopper 118 advance and retreat, and as the spring stopper 118 moves. Thus, the spring force of the tension coil spring 34 can be adjusted. That is, when the male screw member 342 is rotated and the piece member 341 is retracted, the tension coil spring 34 is stretched to increase the spring force, and conversely, when the male screw member 342 is rotated in the direction in which the piece member 341 moves forward, The spring force of the spring 34 is weakened.

  The bracket through which the male screw member 342 is inserted has a locking piece 343 that locks the head of the male screw member 342 as shown in FIG. The shape is arbitrary.

  Here, as described above, in the throttle brake mechanism, the belt 32 is pulled by the spring force of the tension coil spring 34, and the drum 31 is wound by the belt 32, whereby the drive of the chain 20 is braked. By making the spring force of the tension coil spring 34 variable by the rotation of the member 342, the tightening force of the drum 31 by the belt 32 can be adjusted.

  That is, in the state where the male screw member 342 is tightened and the spring force of the tension coil spring 34 is strong, the force of pulling the belt 32 when the throttle lever 137 is returned is large, so that the tightening force of the drum 31 by the belt 32 increases. For this reason, the time from when the throttle lever 137 is returned and braking of the brake device 40 is started to when the chain 20 is stopped can be extremely shortened.

  In contrast, when the male screw member 342 is loosened and the spring force of the tension coil spring 34 is weak, the force that pulls the belt 32 when the throttle lever 137 is returned is small. Therefore, it takes some time until the chain 20 stops. About the length of the braking time of such a chain 20, it can adjust suitably according to the object and feeling of use of logging, for example, it becomes possible to shoot off a branch with remaining power by setting up braking time long. .

  On the other hand, the main body 11 (FIG. 8) is provided with a stopper 375 facing the rear mounting portion 47, and this stopper 375 locks the rear end portion 322 of the belt 32 to restrict the operation of the throttle brake mechanism.

  FIG. 8 is a side view of the brake device 40. The stopper 375 is a rod-shaped member that is inserted into the opening 117 of the main body 11 and protrudes from the rear mounting portion 47, and has a stepped pin portion 375 </ b> A that is inserted into the opening 117 and the rear when the pin portion 375 </ b> A is pushed in. It has an engaging portion 375C that engages with the end surface of the attaching portion 47, and a spring 375E that is disposed between the head portion 375B and the main body 11 of the pin portion 375A.

  Here, in the state shown in FIG. 8, the stopper 375 is not functioning, and the state in which the stopper 375 is functioning is shown in FIG. The stopper 375 can be pushed into the inside of the main body 11 when the throttle lever 137 is rotated and the rear mounting portion 47 moves to the drum 31 side through the wire 136 as shown in FIG. By pushing the head 375B of the stopper 375, the engaging portion 375C moves forward toward the end surface of the rear mounting portion 47, and the engaging portion 375C is engaged with the end surface of the rear mounting portion 47 by the spring force of the spring 375E. The As a result, the movement of the rear end 322 of the belt 32 is restricted, and even when the throttle lever 137 is returned, the wire 136 only sags, and the belt 32 remains loose on the outer peripheral portion 311 of the drum 31. Kept. That is, if the stopper 375 is pushed in, the throttle brake mechanism does not operate.

  When the stopper 375 is pulled out from the main body 11, the engaging portion 375C is disengaged from the end face of the rear mounting portion 47, and the belt 32 is pulled and moved by the spring force of the tension coil spring 34, and by the spring force of the spring 375E. The stopper 375 is pushed up. In this state, the throttle brake mechanism in the brake device 40 operates in conjunction with the operation of the throttle lever 137 in substantially the same manner as in the above embodiment. Such a function of the stopper 375 may be used as appropriate according to the work purpose.

According to this embodiment described above, in addition to the above (1) and (2), the following effects can be obtained.
(3) In the brake device 40, the tension coil spring 34 mounting structure includes the piece member 341 and the male screw member 342, and the spring force of the tension coil spring 34 is made variable by rotating the male screw member 342. The tightening force when the belt 32 winds the drum 31 is variable by the spring force of the tension coil spring 34, and the braking time until the chain 20 stops can be adjusted. As a result, while the chain 20 can be reliably stopped as described above, it is possible to arbitrarily set the stop time of the chain 20 according to the application and operational feeling.
(4) Since the stopper 375 for restricting the movement of the belt 32 is provided, the throttle brake mechanism can be operated even when the stopper 375 is pushed in and locked to the end surface of the rear mounting portion 47 of the belt 32 and the throttle lever 137 is returned. Can be turned off. By using the stopper 375 in this way, it is possible to switch whether or not to operate the throttle brake mechanism according to the purpose of the work, and the handleability can be improved.
[Third Embodiment]
Next, a third embodiment of the present invention will be described.

  In the present embodiment, the stopper 375 in the second embodiment is provided with an electrical switch related to engine start.

  FIG. 10 shows a block diagram of the electric system 50 for starting the engine. When the main switch 51 of the engine is input, the ignition of the CDI magnet or the like is performed only when the stopper switch 52 provided in the stopper 375 is ON. Electricity is supplied between the coil device 53 and the plug 54.

  Here, the stopper switch 52 is configured as an electrical switch between the pin portion 375A (FIG. 8) of the stopper 375 and a contact (not shown) provided in the main body 11, and in a state where the stopper 375 is pulled up. The pin portion 375A and the main body 11 come into contact with each other, and the stopper portion switch 52 is ON, so that the plug 54 can be energized.

  On the other hand, in a state where the stopper 375 is pushed in, the pin portion 375A is separated from the main body 11 and the stopper portion switch 52 is OFF. Even if the main switch 51 is input, the plug 54 is not energized, and the engine Will not be started.

  Therefore, in order to start the engine, it is necessary to operate the main switch 51 after raising the stopper 375. That is, when the stopper 375 is pushed down, the rear mounting portion 47 is locked by the engaging portion 375C, so that the throttle brake mechanism of the brake device 40 is not working. Then, the engine cannot be started.

  The stopper switch 52 is provided with detection means 521 for detecting whether the engine is in a driving state or a non-driving state, and only when the detection means 521 detects that the engine is in a non-driving state. When the stopper 375 is pushed, the stopper switch 52 is turned off. As a result, even if the stopper 375 is pushed down while the engine is driven, the OFF state of the stopper switch 52 is canceled, and the throttle brake mechanism is not activated, and the driven engine is stopped. Absent.

According to this embodiment described above, in addition to the above (1) to (4), the following effects can be obtained.
(5) When the stopper switch 52 is added to the stopper 375 and the stopper 375 is pressed and the throttle brake mechanism is released, the engine cannot be started. Therefore, the throttle brake mechanism is effective unless the stopper 375 is pulled back. It is possible to prevent the engine from starting in the absence of the engine. Thereby, the user-friendly chainsaw 1 can be realized.

  Although the best configuration for carrying out the present invention has been disclosed in the above description, the present invention is not limited to this. That is, the invention has been illustrated and described primarily with respect to particular embodiments, but may be configured for the above-described embodiments without departing from the scope and spirit of the invention. Various modifications and improvements can be made by those skilled in the art in terms of materials, quantity, and other detailed configurations.

  The description limiting the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which removes a part or all of the limitation is included in the present invention.

  For example, in each of the above embodiments, the front end 321 of the belt 32 is biased by the compression coil spring 33 and the rear end 322 of the belt 32 is biased by the tension coil spring 34. The urging direction and the specific configuration of the second urging means are not limited to these and can be determined as appropriate.

  The present invention can be used for an engine-driven chain saw provided with both a throttle brake mechanism and a chain brake mechanism.

1 is a schematic view of a chainsaw in a first embodiment of the present invention. The perspective view which shows the brake device of the chainsaw in the said embodiment. The figure which shows the state in which the throttle lever is rotated in the said embodiment and the chain is driven. The figure of the state which operated the throttle-brake apparatus in the state of FIG. The figure which shows the state of the chain braking by a chain (kickback) brake device at the time of the impact of the chain saw of the said embodiment. The figure which shows the state which returned the throttle lever from the state of FIG. The perspective view which shows the brake device of the chainsaw in 2nd Embodiment of this invention. The figure which shows the state which the stopper is not functioning in the brake device of the said embodiment. The figure which shows the state which the stopper is functioning in the brake device of the said embodiment. The block diagram which shows the electrical switch provided in the stopper in 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Chain saw, 20 ... Chain, 30, 40 ... Brake device, 31 ... Drum, 32 ... Belt, 33 ... Compression coil spring (1st biasing means), 34 ... Tension coil spring (second urging means), 35 ... Locking member, 36 ... Front attachment part (attachment part), 37,47 ... Rear attachment part (attachment part), 119 ... Projection (regulating means), 131 ... Throttle lever, 132 ... Sprocket, 341 ... Piece member (female screw member), 342 ... Male screw member, 371 ... Long hole for projection (long) Hole), 375... Stopper.

Claims (5)

A chain saw comprising: a main body on which an engine is mounted; and a chain provided with a saw blade. The chain saw is used for a chain saw that rotates by driving the engine around a guide member provided on the main body, and stops the chain. Brake device,
A drum provided on a rotating shaft of a sprocket for transmitting the driving force of the engine to the chain and rotating together with the sprocket;
A belt that is wrapped around the drum and pulled out in opposite directions at both ends;
A first urging means and a second urging means for urging both end sides of the belt in directions opposite to each other in a direction in which the drum is tightened;
A locking member for locking the belt to the main body so as to resist the biasing force of the first biasing means;
When the one end side of the belt moves by the urging force of the first urging means, a regulating means for restricting the movement of the other end side of the belt to a certain range following the movement on the one end side. A chain saw brake device characterized by being provided. In the chain saw brake device according to claim 1,
The belt has an attachment portion to which the second urging means is attached;
In the attachment portion, a long hole extending along the longitudinal direction of the belt is formed,
The chain saw brake device, wherein the restricting means is a protrusion inserted into the elongated hole. The chain saw brake device according to claim 1 or 2,
The second biasing means is a coil spring;
One end side of the coil spring is attached to the other end side of the belt, and the other end side of the coil spring is attached to a female screw member in which a female screw is formed,
A male screw member attached to the main body and formed with a male screw is screwed onto the female screw member,
The chain saw brake device, wherein the rotation of the male screw member allows the female screw member to advance and retract along the biasing direction of the coil spring. In the chain saw brake device according to any one of claims 1 to 3,
The main body includes a throttle lever for adjusting the output of the engine, and the throttle lever is engaged with an end surface on the other end side of the belt in a state in which the throttle lever rotates in a direction against the urging force of the second urging means. A chain saw brake device characterized in that a stopper is provided. A chain saw comprising the chain saw brake device according to any one of claims 1 to 4.

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