JP2010269492A - Chainsaw - Google Patents

Abstract

A chain saw capable of quickly braking a drive shaft during kickback is provided.
A saw chain, a drive shaft that drives the saw chain, a handle that is gripped by a user, and a handle that is disposed in the vicinity of the handle and is supported so as to be swingable about a first swing shaft 40a. The hand guard 40 and the second swing shaft 64 are supported so as to be swingable. The support 60 swings in conjunction with the hand guard 40, and the brake that brakes the drive shaft in conjunction with the support 60. A chain saw having a gear mechanism 40b, 62 that connects the member 70, the hand guard 40 and the support 60 to each other, and makes the swing angle of the support 60 larger than the swing angle of the hand guard 40.
[Selection] Figure 4

Description

  The present invention relates to a chain saw that stops a saw chain when a hand guard swings.

  The chain saw is provided with an emergency stop mechanism in preparation for kickback. For example, in Patent Document 1, a hand guard that is swingably supported near a handle, a link mechanism that interlocks with the hand guard, a coil spring that expands and contracts in conjunction with the link mechanism, and a coil spring extends. Chain saws are sometimes disclosed having a brake band that sometimes brakes the drive shaft. When kickback occurs, the operator's hand hits the hand guard, and the hand guard swings forward from the fixed position. Then, the link mechanism interlocks to open the coil spring, and the coil spring extends. As the coil spring extends, the brake band tightens the drive shaft and brakes. As a result, the saw chain is brought to an emergency stop.

JP-A-9-29709

  In the chain saw emergency stop mechanism, when the hand guard swings, it is necessary to quickly brake the drive shaft to stop the saw chain. For this purpose, it is preferable that the swing angle of the hand guard necessary for operating the braking member is as small as possible. That is, it is preferable that even if the hand guard swings small, the member interlocked with the hand guard moves greatly and the braking member operates quickly.

  The present invention has been created in view of the above-described circumstances, and an object thereof is to provide a chainsaw that can quickly brake a drive shaft at the time of kickback.

The chain saw of the present invention includes a saw chain, a drive shaft, a handle, a hand guard, a support, a braking member, and a gear mechanism. The drive shaft drives the saw chain. The handle is gripped by the user. The hand guard is disposed in the vicinity of the handle and is supported so as to be swingable about the first swing shaft. The support is supported so as to be swingable about the second swing shaft, and swings in conjunction with the hand guard. The braking member brakes the drive shaft in conjunction with the support. The gear mechanism connects the hand guard and the support to each other, and makes the swing angle of the support larger than the swing angle of the hand guard.
In this chain saw, when the hand guard swings, the support swings by interlocking with the gear mechanism. At this time, the gear mechanism makes the swing angle of the support larger than the swing angle of the hand guard. For this reason, even if the hand guard swings small, the support swings greatly, and the braking member brakes the drive shaft. Therefore, this chainsaw can quickly brake the drive shaft during kickback.

  In the above-described chain saw, it is preferable that the gear mechanism has a first gear provided on the hand guard and a second gear provided on the support, and the first gear and the second gear mesh with each other. .

In the above-described chain saw, it is preferable that the brake member is slidable in the axial direction and has a brake pin that contacts the outer peripheral surface of the drive shaft in conjunction with the support. In addition, it is preferable that the outer peripheral surface of the drive shaft is formed with a standing surface that contacts the side surface of the brake pin when the brake pin contacts the outer peripheral surface of the drive shaft.
In this chain saw, the drive shaft is braked when the standing surface of the drive shaft comes into contact with the side surface of the brake pin. Since the drive shaft is braked not by frictional force but by physically colliding the side surface of the brake pin with the standing surface, the drive shaft can be stopped more quickly. In addition, since the sliding direction of the braking pin and the direction in which the standing surface contacts the braking pin are different, the braking pin is not pushed back by the contact of the standing surface. Therefore, the drive shaft can be stopped appropriately.

When the hand guard is in the normal position, the chain saw described above is supported by the support and fixed at a position where the brake pin does not contact the drive shaft. When the hand guard swings to the brake position, the brake pin contacts the drive shaft. It is preferable. And it is preferable that the site | part in which the 2nd gear of a support is formed, and the site | part which supports the brake pin of a support are located in the other side on both sides of the 2nd rocking | fluctuation shaft. Further, the distance from the portion supporting the brake pin of the support to the second swing shaft may be longer than the distance from the portion where the second gear of the support is formed to the second swing shaft. preferable.
According to such a configuration, when the support swings, the amount of movement of the portion that supports the brake pin of the support becomes larger. For this reason, when the support swings, the brake pin is quickly released, and the brake pin brakes the drive shaft. According to this chain saw, the drive shaft can be stopped more quickly during kickback.

The chain saw described above may have a stopper that prevents the hand guard from swinging from the normal position to the braking position by contacting the support, and cancels the restriction when a predetermined amount of force is received from the support. preferable. Moreover, it is preferable that the site | part which the stopper of a support contacts is located in the same side as the said site | part which supports the brake pin of a support with respect to the 2nd rocking | fluctuation shaft. It is preferable that the distance from the portion where the stopper of the support abuts to the second swing shaft is longer than the distance from the portion supporting the brake pin of the support to the second swing shaft.
According to such a configuration, the hand guard is restricted from swinging from the normal position to the braking position by the stopper. This prevents the hand guard from accidentally swinging. Further, since the distance from the portion where the stopper of the support comes into contact with the second swing shaft is long, the contact portion is a portion that moves greatly when the support swings. For this reason, the stopper can regulate the swing of the support with a relatively weak force. That is, the stopper can regulate the swing of the hand guard with a relatively weak force. For this reason, the structure of the stopper can be simplified.

  According to the chain saw of the present invention, the drive shaft can be quickly braked at the time of kickback, and the saw chain can be immediately stopped at the time of kickback.

FIG. FIG. 2 is an external view of the chainsaw 10 with a cover 24 removed. FIG. 3 is a cross-sectional view of the chain saw 10 viewed from a cross section along the rotation axis of the drive shaft 48 in a normal state. Sectional drawing of the chainsaw 10 in the IV-IV line of FIG. FIG. 4 is a cross-sectional view of the chainsaw 10 viewed from a cross section along the rotation axis of the drive shaft 48 at an emergency stop. Sectional drawing of the chainsaw 10 in the VI-VI line of FIG.

  A chain saw according to an embodiment will be described with reference to the drawings. FIG. 1 shows an external view of the chainsaw 10. FIG. 2 shows an external view of the chainsaw 10 with a cover 24 and a saw chain 32 removed from the main body 12 to be described later. The chain saw 10 includes a main body 12, a guide bar 30 attached to the main body 12, and a saw chain 32. In addition, in FIG. 1, the part at the front end side of the guide bar 30 is not shown.

  As shown in FIGS. 1 and 2, the main body 12 includes a motor 16, a first grip 14, a second grip 18, and a sprocket 38. The second grip 18 is provided with a trigger switch 20 that activates the chainsaw 10. The sprocket 38 is provided on the side surface of the main body 12 and is rotatably supported by the main body 12. The sprocket 38 is connected to the motor 16 and is rotationally driven by the motor 16. The motor 16 is configured to be supplied with power from the battery 22 in conjunction with an operation on the trigger switch 20. The battery 22 is detachably attached to the main body 12.

A guide bar 30 is attached to the main body 12. The guide bar 30 is disposed adjacent to the sprocket 38. The guide bar 30 and the sprocket 38 are located on substantially the same plane. The saw chain 32 (not shown in FIG. 2) is spanned so as to surround both the sprocket 38 and the guide bar 30.
In the chainsaw 10, when the operator turns on the trigger switch 20, the motor 16 as a prime mover starts rotating. As the motor 16 rotates, the sprocket 38 rotates relative to the main body 12. As a result, the saw chain 32 as a tool rotates along the periphery of the sprocket 38 and the guide bar 30. An operator can cut wood or the like by pressing the rotating saw chain 32.

  As shown in FIG. 1, a hand guard 40 is installed at a position adjacent to the first grip 14. The hand guard 40 is disposed so as to cover the hand of the user holding the first grip 14 when the user holds the first grip 14. The hand guard 40 is supported to be swingable with respect to the main body 12. When a kickback occurs when the chainsaw 10 is used and the chainsaw 10 jumps up, the hand guard 40 swings against the user's hand. When the hand guard 40 swings, the rotation of the saw chain 32 is urgently stopped by an emergency stop mechanism described later. The emergency stop mechanism will be described in detail later.

FIG. 3 shows a cross-sectional view of the chainsaw 10 along the rotational axis of the sprocket 38. FIG. 4 shows a cross-sectional view of the chainsaw 10 taken along the line IV-IV in FIG. 3 and 4 show cross-sectional views in a state where the emergency stop mechanism is not operating.
As shown in FIG. 3, a drive shaft 48 is installed inside the main body 12. The drive shaft 48 includes a shaft 42, a holder 44, and a braking plate 46. The shaft 42 has a tip connected to the center of the sprocket 38 and extends along the rotation axis of the sprocket 38. The shaft 42 is rotatably supported with respect to the main body 12 by bearings 50 and 52. The brake plate 46 has a substantially disk shape. A through hole is formed at the center of the brake plate 46. The brake plate 46 is fixed to the shaft 42 in a state where the shaft 42 is inserted into the through hole. As shown in FIG. 4, steps having standing surfaces 46 a are formed at two locations on the outer circumferential surface of the brake plate 46. The standing surface 46 a faces the rotation direction of the brake plate 46. The holder 44 has a substantially disk shape. As shown in FIG. 3, a through hole is formed at the center of the holder 44. The holder 44 is fixed to the shaft 42 with the shaft 42 inserted through the through hole. The holder 44 is fixed to the shaft 42 at a position between the sprocket 38 and the brake plate 46. On the side surface of the holder 44, a recess 44 a is formed that extends circumferentially around the rotation axis of the shaft 42. A coil spring 49 is disposed in the recess 44 a of the holder 44. A drive gear 54 is disposed between the holder 44 and the brake plate 46. A through hole is formed at the center of the drive gear 54. A coil spring 49 is inserted into the through hole of the drive gear 54. The coil spring 49 is a coil spring formed by winding a wire having a rectangular cross section. The coil spring 49 is inserted into both the recess 44a of the holder 44 and the through hole of the drive gear 54 with the winding diameter reduced. Therefore, the outer peripheral surface of the coil spring 49 is in contact with the inner surface of the recess 44a and the inner surface of the through hole of the drive gear 54, and urges these inner surfaces in the direction of increasing the diameter. The coil spring 49 is fixed to both the holder 44 and the drive gear 54 by this urging force. That is, the holder 44 is connected to the drive gear 54 by the coil spring 49. The drive gear 54 meshes with a gear provided on the rotating shaft of the motor 16 (see FIG. 1) at a position not shown.

  The normal operation of the chainsaw 10 will be described. When electric power is supplied to the motor 16 and the rotation shaft of the motor 16 rotates, the drive gear 54 rotates. Since the drive gear 54 is connected to the drive shaft 48 via the coil spring 49, when the drive gear 54 rotates, the entire drive shaft 48 rotates. Then, the sprocket 38 fixed to the tip of the shaft 42 rotates, and the saw chain 32 rotates.

Next, the emergency stop mechanism of the chainsaw 10 will be described. As shown in FIGS. 3 and 4, the emergency stop mechanism includes a hand guard 40, a support 60, a braking pin 70, and a leaf spring 80.
As described above, the hand guard 40 is installed at a position adjacent to the first grip 14. The hand guard 40 is supported so as to be swingable with respect to the main body 12 about the swing shaft 40a. The hand guard 40 swings between a position shown in FIG. 4 (hereinafter referred to as a normal position) and a position shown in FIG. 6 (hereinafter referred to as a braking position). The hand guard 40 is formed with a gear portion 40b. The gear portion 40b is composed of a plurality of gear teeth provided radially about the swing shaft 40a.

  The support 60 is disposed at a position adjacent to the hand guard 40. The support 60 is supported so as to be swingable with respect to the main body 12 about the swing shaft 64. A gear portion 62 is formed on the support 60. The gear portion 62 is configured by a plurality of gear teeth provided radially about the swing shaft 64. The gear portion 62 of the support 60 meshes with the gear portion 40b of the hand guard 40. Therefore, the support 60 swings in conjunction with the hand guard 40. The support 60 swings between a position shown in FIG. 4 (hereinafter referred to as “forbidden position”) and a position shown in FIG. 6 (hereinafter referred to as “open position”). As shown in FIG. 4, the distance from the engaging portion to the swing shaft 40a is larger than the distance from the portion where the gear portion 40b and the gear portion 62 are engaged (hereinafter referred to as the engaging portion) to the swing shaft 64. Is longer. Therefore, the swing angle of the support 60 is larger than the swing angle of the hand guard 40. Further, the support 60 is provided with a through hole 66 and a regulation pin 68. The through hole 66 and the regulation pin 68 are provided on the opposite side of the gear portion 62 with the swing shaft 64 interposed therebetween. The restriction pin 68 is provided at the tip of the support 60, and the through hole 66 is provided between the swing shaft 64 and the restriction pin 68. That is, the distance from the swing shaft 64 to the restriction pin 68 is longer than the distance from the swing shaft 64 to the through hole 66. A leaf spring 80 is provided at a position adjacent to the restriction pin 68. The leaf spring 80 is formed with a protrusion 80a. As shown in FIG. 4, in a state where the support 60 is in the prohibited position, the restriction pin 68 of the support 60 is in contact with and caught by the protrusion 80 a of the leaf spring 80. This restricts the support 60 from swinging from the prohibited position to the open position. That is, the hand guard 40 is restricted from swinging from the normal position to the braking position.

  The braking pin 70 is a substantially cylindrical member. The brake pin 70 is inserted into the through hole 66 of the support 60. The brake pin 70 can slide along its central axis. The brake pin 70 slides between a non-contact position where it does not contact the brake plate 46 as shown in FIGS. 3 and 4 and a contact position where it contacts the outer peripheral surface of the brake plate 46 as shown in FIGS. Can move. That is, the brake pin 70 can slide in a direction toward the rotation center of the brake plate 46. A flange portion 71 is formed at a substantially central portion in the longitudinal direction of the braking pin 70. The flange portion 71 is located on the upper side of the support 60 and is in contact with the upper surface of the support 60 (portion around the through hole 66). A portion above the flange portion 71 of the braking pin 70 is inserted into the coil spring 72. The end of the coil spring 72 opposite to the flange portion 71 is in contact with the support portion 13 provided in the main body 12. The coil spring 72 is in contact with the flange portion 71 and biases the braking pin 70 toward the braking plate 46. As shown in FIG. 4, in a state where the support 60 is in the prohibition position, the braking pin 70 is fixed to the non-contact position by the flange portion 71 being supported by the support 60.

  The operation of the chainsaw 10 at the time of emergency stop will be described. When a kickback occurs when the chainsaw 10 is used and the chainsaw 10 jumps up, the hand guard 40 hits the user's hand, and the hand guard 40 is strongly pressed from the normal position toward the braking position. Then, the restriction pin 68 of the support 60 is strongly pressed toward the protrusion 80 a of the leaf spring 80. As a result, the leaf spring 80 is elastically deformed, and the regulation pin 68 gets over the protruding portion 80a. That is, the hand guard 40 swings from the normal position to the braking position, and the support 60 swings from the prohibited position to the open position. Then, the braking pin 70 is moved from the non-contact position to the contact position by the urging force of the coil spring 72. That is, the brake pin 70 slides and the tip of the brake pin 70 comes into contact with the outer peripheral surface of the brake plate 46. At this time, since the brake plate 46 (that is, the drive shaft 48) is rotating, the standing surface 46a of the brake plate 46 contacts the side surface of the brake pin 70 as shown in FIG. As a result, the drive shaft 48 is braked, and the rotation of the drive shaft 48 stops. That is, the rotation of the sprocket 38 stops and the rotation of the saw chain 32 stops. In this way, when kickback occurs, the saw chain 32 can be stopped immediately. In an emergency stop, the drive shaft 48 is braked, while the drive gear 54 is continuously rotated by the motor 16. For this reason, a force is applied to the coil spring 49 in the twisting direction, and the coil spring 49 is deformed to reduce its diameter. For this reason, the connection between the drive gear 54 and the holder 44 is eliminated. That is, the drive gear 54 rotates relative to the drive shaft 48 (that is, idle). For this reason, at the time of emergency stop, the driving force of the motor 16 is not transmitted to the drive shaft 48, and the rotation of the saw chain 32 can be quickly stopped by the emergency stop mechanism.

  As described above, in the chainsaw 10 of the embodiment, the hand guard 40 and the support 60 are connected by the gear mechanism including the gear portion 40 b and the gear portion 62. In the gear mechanism, the gear ratio is set so that the swing angle of the support 60 is larger than the swing angle of the hand guard 40. Therefore, even if the hand guard 40 swings small, the support 60 swings greatly, and the brake pin 70 in the non-contact position is quickly released and moved to the contact position. For this reason, according to the chain saw 10 of an Example, when kickback arises, rotation of the saw chain 32 can be stopped rapidly. Further, the distance between the portion that supports the brake pin 70 (the upper surface portion of the support 60 around the through hole 66) and the swing shaft 64 is larger than the distance between the engaging portion of the gear portion 62 and the swing shaft 64. Since the support 60 is long, the movement amount of the through hole 66 is large when the support 60 swings. Also by this, the brake pin 70 can be opened quickly, and the rotation of the saw chain 32 can be stopped more quickly.

  In the chainsaw 10 of the embodiment, the regulation pin 68 is formed at the tip of the support 60, and the distance between the regulation pin 68 and the swing shaft 64 is long. Accordingly, the swinging of the support 60 can be restricted by a relatively weak force of the leaf spring 80. For this reason, the structure of the leaf spring 80 can be simplified.

  Further, in the chain saw 10 of the embodiment, a standing surface 46 a is formed on the outer peripheral surface of the brake plate 46. When the brake pin 70 comes into contact with the brake plate 46, the standing surface 46 a comes into contact with the side surface of the brake pin 70 by the rotation of the brake plate 46. Thereby, the rotation of the drive shaft 48 is stopped. Not only the frictional force but also the side surface of the brake pin 70 physically collides with the standing surface 46a of the brake plate 46, whereby the drive shaft 48 is braked, so that the drive shaft 48 can be quickly stopped. Further, since the direction in which the standing surface 46a of the braking plate 46 abuts against the braking pin 70 is substantially orthogonal to the sliding direction of the braking pin 70, the braking pin 70 is pushed back by the abutment of the standing surface 46a. There is nothing. Therefore, the drive shaft 48 can be stopped reliably.

  In the above-described embodiment, the gear mechanism that connects the hand guard 40 and the support 60 is constituted by the two gear portions 40b and 62. However, the gear mechanism may be configured with more gears. For example, a two-stage gear that meshes with both the gear part 40b and the gear part 62 is provided between the gear part 40b and the gear part 62, and the swing of the hand guard 40 is transmitted to the support 60 through the two-stage gear. You may do it. Thus, the swing angle of the support 60 can be increased by increasing the number of gears.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

10: Chain saw 12: Main body 14: First grip 16: Motor 18: Second grip 20: Trigger switch 22: Battery 24: Cover 30: Guide bar 32: Saw chain 38: Sprocket 40: Hand guard 40a: Oscillating shaft 40b : Gear portion 42: Shaft 44: Holder 46: Braking plate 46 a: Stepped portion 48: Drive shaft 49: Coil spring 54: Drive gear 60: Support 62: Gear portion 64: Oscillating shaft 66: Through hole 68: Restricting pin 70 : Braking pin 72: Coil spring 80: Leaf spring 80a: Projection

Claims (5)

With a saw chain,
A drive shaft for driving the saw chain;
A handle gripped by the user;
A hand guard disposed in the vicinity of the handle and supported so as to be swingable about the first swing shaft;
A support which is supported so as to be swingable about the second swing axis, and swings in conjunction with the hand guard;
A braking member that brakes the drive shaft in conjunction with the support;
A gear mechanism that connects the hand guard and the support to each other, and makes the swing angle of the support larger than the swing angle of the hand guard,
Chainsaw with. The gear mechanism has a first gear provided on the hand guard and a second gear provided on the support,
The chain saw according to claim 1, wherein the first gear and the second gear mesh with each other. The brake member is slidable in the axial direction and has a brake pin that contacts the outer peripheral surface of the drive shaft in conjunction with the support.
The standing surface which contacts the side surface of a brake pin when the brake pin contacts the outer peripheral surface of a drive shaft is formed in the outer peripheral surface of a drive shaft, The Claim 1 or 2 characterized by the above-mentioned. Chainsaw. When the hand guard is in the normal position, it is supported by the support and fixed to a position where the brake pin does not contact the drive shaft.When the hand guard swings to the brake position, the brake pin contacts the drive shaft,
The portion where the second gear of the support is formed and the portion that supports the brake pin of the support are located on opposite sides of the second swing shaft,
The distance from the part supporting the braking pin of the support to the second rocking shaft is longer than the distance from the part where the second gear of the support is formed to the second rocking shaft. The chain saw according to claim 3. It has a stopper that restricts the hand guard from swinging from the normal position to the braking position by coming into contact with the support, and releases the restriction when receiving a force of a predetermined amount or more from the support,
The part with which the stopper of the support comes into contact is located on the same side as the part that supports the brake pin of the support with respect to the second swing shaft,
5. The distance from the portion where the stopper of the support abuts to the second swing shaft is longer than the distance from the portion supporting the brake pin of the support to the second swing shaft. Chainsaw described in

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