JP2003251602A - Saw chain tension adjusting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust the tension of a saw chain appropriately. <P>SOLUTION: This saw chain tension adjusting device comprises a guide bar 5 of a saw chain supported by a housing 1 in a freely sliding manner in a tension adjusting direction, a cam 13 superposed on the side face of the guide bar 5 so that the cam 13 comes into contact with a projecting part 11 jutting out of the side face of the guide bar 5, an adjusting means which slides the guide bar 5 through the projecting part 11 by manipulating the cam 13, fixed screws 9 and 23 for fixing the guide bar 5 to the housing 1 and a fixed handle 21 for manipulating the fixed screws 9 and 23. In addition, the adjustable means has an adjustable handle 14 covering the fixed handle 21 in a relatively rotatable manner and the cam 13 is fixed to the adjustable handle 14, and further the guide bar 5, the cam 13 and the adjustable handle 14 are integrally fastened to the housing 1 by manipulating the fixed screws 9 and 23 with the help of the fixed handle 21. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a saw chain tension adjusting device.

[0002]

2. Description of the Related Art A chain saw has a prime mover in its housing for driving the saw chain. A guide bar projects from the housing, and an endless saw chain is wound around the guide bar and the sprocket wheel inside the housing. When the sprocket wheel rotates due to activation of the prime mover, the saw chain runs along the guide bar, and the running saw chain cuts the work. The saw chain must be stretched between the sprocket wheel and the guide bar with proper tension, but a tension adjusting device is provided on the chain saw in order to adjust the tension of the saw chain.

[0003] A tension force adjusting device disclosed in German Patent DE 19931250 contacts a guide bar of a saw chain slidably supported in a housing in a tension adjusting direction and a convex portion protruding from a side surface of the guide bar. A cam that overlaps the side surface of the guide bar, an adjusting means that operates the cam to slide the guide bar through the protrusion, a fixing screw that fixes the guide bar to the housing, and a fixing handle that operates the fixing screw. To have. To adjust the tension, operate the fixed handle, loosen the fixing screw to release the guide bar, and then turn the fixed handle in the direction to tighten it again. When the fixed handle is turned in the tightening direction, the cam rotates with respect to the convex portion via the adjusting means. When the cam presses the convex portion, the guide bar slides on the housing in the direction of increasing the tensioning force to increase the tensioning force of the saw chain. When the tension is adjusted, the fixing screw acts so as to tighten the guide bar against the housing to fix it. This completes the adjustment of the tension force.

[0004]

The above-mentioned conventional tension adjusting device is provided with a clutch which is biased by a spring between the fixed handle and the cam as the adjusting means, and when the fixed handle is rotated, its torque is transmitted through the clutch. Transmitted to the cam,
As a result, the guide bar slides, so that the adjustment of the tension force is influenced by the engagement force of the clutch, and the desired tension force may not be obtained.

An object of the present invention is to provide a tension adjusting device for a saw chain which can solve the above problems.

[0006]

In order to solve the above problems, the invention according to claim 1 is a saw chain guide bar (5) supported by a housing (1) slidably in a tension adjusting direction. A cam (13) overlaid on the side surface of the guide bar (5) so as to come into contact with the convex portion (11) provided on the side surface of the guide bar (5), and the convex portion (11) by operating the cam (13). Adjusting means for sliding the guide bar (5) through the fixing screw, fixing screws (9, 23) for fixing the guide bar (5) to the housing (1), and fixing screws (9, 2).
A tension adjusting device for a saw chain comprising a fixed handle (21) for operating 3), wherein the adjusting means includes an adjusting handle (14) which is rotatably covered by the fixed handle (21). The cam (13) is fixed to (14), and the guide bar (5), the cam (13) and the adjusting handle (14) are moved to the housing (1) by operating the fixing screws (9, 23) by the fixing handle (21). ) The saw chain tension adjustment device that can be tightened together is used.

According to a second aspect of the invention, in the saw chain tension adjusting device according to the first aspect, the adjusting handle (14) is screwed on the fixing handle (21) by the fixing screws (9, 23). Holds slidably in both directions and holds both handles (14, 21) between the handles (14, 21)
A saw chain tension force adjusting device in which a spring (24) for urging the saw chain is inserted is used.

According to a third aspect of the invention, in the saw chain tension adjusting device according to the first or second aspect, the outer periphery of the fixed handle (21) is the adjusting handle (1).
4) Adopt a saw chain tension force adjusting device formed so as to locally protrude from the outer circumference.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the chain saw includes a housing 1 and a front handle 2 which is integrated with the housing 1 and projects from a side surface of the housing 1.
A guard 3 which is integrated with the housing 1 and which protrudes from a side surface of a front end of the housing 1, a rear handle 4 which is integrally formed with the housing 1 and which protrudes rearward from a rear portion of the housing 1, and a front end of the housing 1 to a front side. It has a protruding guide bar 5 and an endless saw chain (not shown) wound around the guide bar 5.

Inside the housing 1, a motor (not shown) as a prime mover is horizontally installed, and as shown in FIGS. 3 and 4, a sprocket wheel 6 driven by rotation of the motor is arranged. When the motor is started, the rotation of the motor is transmitted to the sprocket wheel 6 via a reduction gear or the like. Due to the rotation of the sprocket wheel 6, the saw chain runs along the periphery of the guide bar 5 and cuts a work such as wood.

The saw chain needs to be tensioned between the sprocket wheel 6 and the guide bar 5 with an appropriate tension force. A tension force adjusting device for adjusting this tension force is used in the chain saw in the following manner. It is provided in.

As shown in FIGS. 1 to 5, the right side (or the left side) of the housing 1 in which the sprocket wheel 6 is provided is covered with a lid 7 as a cover. Lid 7
Is integrated with the housing 1 by being fixed to the housing 1 with a fixed handle or the like described later. The lid 7 also functions as a guide bar retainer.
Are pressed against the housing 1 and fixed.

The guide bar 5 is supported by the housing 1 so as to be slidable in the tension adjusting direction. As shown in FIGS. 2 to 4, an elongated hole 8 is formed in the longitudinal direction of the guide bar 5 at a position where the guide bar 5 is covered with the lid body 7.
A screw cylinder 9 and a pin 10 protruding in parallel from the housing 1 are inserted in the housing. The guide bar 5 is slidable on the housing 1 in the front-back direction of the chainsaw, that is, in the tension adjusting direction while being supported by the screw cylinder 9 and the pin 10 in a state where a fixing screw described later including the screw cylinder 9 is loosened.

A convex portion 11 is provided on the side surface of the guide bar 5 on the side opposite to the housing. The convex portion 11 is formed on the side surface of the ring 12 having a substantially elliptical shape. By fixing the ring 12 to the side surface of the guide bar 5, the convex portion 11 projects from the side surface of the guide bar 5 so as to straddle the elongated hole 8 of the guide bar 5.

A cam 13 is superposed on the side surface of the guide bar 5, and the cam surface of the cam 13 is in contact with the convex portion 11 projecting from the side surface of the guide bar 5. As shown in FIGS. 3 and 4,
A boss 13a is formed on the side surface of the cam 13 on the guide bar 5 side, and the boss 13a contacts the side surface of the guide bar 5.

The cam 13 is fixed to an adjusting handle 14 which is an adjusting means, and can rotate integrally with the adjusting handle 14. As shown in FIGS. 3 and 6, the adjustment handle 14 is a cylindrical dial, and the guide bar 5 of the end plate thereof is used.
A cam 13 is fixed to the side end surface with a set screw 15 or the like. A plurality of leaf spring pieces 16 are formed in the end plate by slits, and these leaf spring pieces 16 are radially arranged around the outer periphery of the cam 13. Serrations 17a are formed on the end surface of each leaf spring piece 16 on the guide bar 5 side so as to extend along the circumference around the axis of the adjustment handle 14. A locking piece 18 for locking a fixed handle, which will be described later, is provided on the end surface of the end plate of the adjustment handle 14 opposite to the guide bar 5.
On the outer peripheral surface of the cylinder that surrounds the end plate of the adjustment handle 14, irregularities for hanging a finger are formed at a constant pitch. With the fixing screw to be described later loosened, put a finger around the adjustment handle 14 and rotate the adjustment handle 14, and then the cam 13 will project into the convex portion 1.
Since it rotates while being in contact with 1, the guide bar 5 slides in its longitudinal direction, that is, the tension adjusting direction.

As shown in FIGS. 3 and 5, the adjusting handle 14 is rotatably fitted in the lid 7. The lid 7 is formed with a recess for fitting the adjustment handle 14,
A circular hole into which the cam 13 and the convex portion 11 enter is formed in the center of the concave portion, and a serration 17b that meshes with the serration 17a of the adjusting handle 14 is formed around the circular hole. An engaging piece 19 is formed on the opening peripheral edge of the concave portion, and a protrusion 20 that engages with the engaging piece 19 and prevents the adjusting handle 14 from falling out of the concave portion is formed on the outer periphery of the cylinder of the adjusting handle 14. The adjusting handle 14 is rotatable on the lid body 7 while being fitted in the recess of the lid body 7, and is slightly slidable in the axial direction thereof. When the adjustment handle 14 is fixed to the housing 1 side by the operation of a fixed handle described later, the serration 17a of the leaf spring piece 16 meshes with the serration 17b on the lid 7 side, and rotation is prevented.

The adjustment handle 14 is rotatably covered on the fixed handle 21 on the side opposite to the lid. The fixed handle 21 has a cylinder 21 a that can enter the cylinder of the adjustment handle 14 and contact the end plate of the adjustment handle 14.
The locking piece 18 described above is provided on the inner circumference of the cylinder of the adjustment handle 14.
A protrusion 22 is formed on the outer periphery of the cylinder 21a of the fixed handle 21 to engage the locking piece 18 and prevent the fixed handle 21 from falling off the adjustment handle 14. Fixed handle 21
Is rotatable relative to the adjusting handle 14 while being fitted in the adjusting handle 14, and is relatively slidable in the axial direction thereof.

As shown in FIG. 3, the fixed handle 21 has a threaded rod 2 which is screwed into the threaded barrel 9 on the housing 1 side.
3 is fixed. On the inner surface of the end plate of the fixed handle 21,
A boss 21b for holding the screw rod 23 is formed.
The screw rod 23 penetrates through the centers of the adjusting handle 14 and the cam 13, and further penetrates through the elongated hole 8 of the guide bar 5 to be screwed into the screw cylinder 9 on the housing 1 side. The screw rod 23 and the screw cylinder 9 form a fixing screw for fixing the guide bar 5 to the housing 1. Turn the fixed handle 21,
When the fixing screw is tightened, as shown in FIGS. 2 and 3,
The boss 21b of the fixed handle 21 presses the cam 13 and the guide bar 5 onto the housing 1, and the cylinder 21a of the fixed handle 21 presses the end plate of the adjustment handle 14, the lid 7 and the guide bar 5 onto the housing 1 and, as a result, the guide The bar 5, the cam 13, the adjustment handle 14, the lid 7 and the fixed handle 21 are integrally tightened and fixed to the housing 1.

As described above, the fixed handle 21 is slidable in the axial direction of the fixed handle 21, that is, the screw rod 23 of the fixing screw, in the state of being fitted in the adjusting handle 14, as shown in FIG. A compression coil spring 24 is inserted between the handles 14 and 21 to urge the handles 14 and 21 away from each other. Fixed handle 21
When the screw rod 23 of the fixing screw is turned in the direction of being loosened by operating, the compression coil spring 24 is rotated as shown in FIGS.
Due to the restoring action, the fixed handle 21 and the adjustment handle 14 are slid relative to each other so that the locking piece 18 and the projection 22 are engaged with each other to be integrated. As a result, when tightening the fixing screw again, the cam surface of the cam 13 can be brought into contact with the convex portion 11 only by holding the fixing handle 21 and turning the screw rod 23, and the operability is improved.

The fixed handle 21 may be formed such that its outer circumference projects entirely from the outer circumference of the adjustment handle 14, but as shown in FIGS. 3 and 5, it is desirable that the fixed handle 21 has an outer circumference. It is formed so as to locally protrude from the outer periphery of the adjustment handle 14. Therefore, when operating both handles 14, 21 individually,
It is easy to put your finger on 1 and the operability is improved.

Next, the operation of the chain saw tension adjusting device configured as described above will be described.

In order to adjust the tension of the saw chain, the fixed handle 21 in the fixed state shown in FIGS. 2 and 3 is turned to loosen the fixing screw consisting of the screw cylinder 9 and the screw rod 23. As a result, as shown in FIGS. 7 and 8, the guide bar 5,
The cam 13, the adjustment handle 14 and the like are released from the pressure on the housing 1, the guide bar 5 is slidable with respect to the housing 1, the serration 17a of the adjustment handle 14 is separable from the serration 17b of the lid 7, and the adjustment handle is provided. The engaging piece 18 of the compression coil spring 24 abuts on the projection 22 of the fixed handle 21 by the urging force of the compression coil spring 24, and is integrated with the fixed handle 21 and can rotate together.

As shown in FIGS. 9 and 10, the fixed handle 2
When 1 is further turned, the cam 13 is completely separated from the convex portion 11. Although not shown, the lid 7, the fixed handle 21 and the like are separated from the housing 1 by separating the screw rod 23 from the screw cylinder 9. Further, the fixed handle 21, the adjustment handle 14, the cam 13 and the screw rod 23 may be integrally separated from the lid body 7.

When the fixing screw 21 is loosened and the adjusting handle 14 is rotated in this manner, the cam 13 rotates integrally with the adjusting handle 14, and the sliding contact between the cam 13 and the convex portion 11 causes the pin 10 to rotate. The guide bar 5 slides on the housing 1 by the guiding action of the screw cylinder 9 and the elongated hole 8. The tension of the saw chain is
Since the force is directly transmitted to the finger through the cam 13 and the adjustment handle 14, the tension force is adjusted to an appropriate level. Further, the force applied to the adjusting handle 14 by fingers is accurately transmitted to the guide bar 5 and the saw chain. As a result, the tension of the saw chain is adjusted.

Further, when the adjusting handle 14 is rotated, the fixed handle 21 is integrated with the adjusting handle 14 through the contact between the projection 22 and the locking piece 18 by the urging force of the compression coil spring 24. Was accompanied by
The screw rod 23 is screwed toward the housing 1.

When the tension force of the saw chain reaches an appropriate level by the turning operation of the adjusting handle 14, the fixed handle 21 is rotated in the tightening direction of the fixing screw to resist the urging force of the compression coil spring 24. And the fixed handle 21 approaches the adjustment handle 14 side, and the fixed handle 21
The boss 21b presses the cam 13 and the guide bar 5 against the housing 1, and the cylinder 21a of the fixed handle 21 presses the end plate of the adjustment handle 14, the lid 7 and the guide bar 5 onto the housing 1. As a result, the guide bar 5 and the cam 1
3, the adjustment handle 14, the lid 7 and the fixed handle 21 are integrally tightened and fixed to the housing 1, and the adjustment of the tension force is completed.

[0029]

According to the first aspect of the invention, the guide bar of the saw chain slidably supported in the housing in the tension adjusting direction and the convex portion protruding from the side surface of the guide bar are brought into contact with each other. The cam includes a cam that is placed on the side surface of the guide bar, an adjusting unit that operates the cam to slide the guide bar through the protrusion, a fixing screw that fixes the guide bar to the housing, and a fixing handle that operates the fixing screw. In the tension force adjusting device for a saw chain, the adjusting means includes an adjusting handle which is rotatably covered on the fixed handle, and the cam is fixed to the adjusting handle.
Since the guide bar, cam and adjustment handle can be tightened together with the housing by operating the fixing screw with the fixing handle, the guide bar can be rotated by rotating the cam directly with the adjustment handle to securely slide the saw chain. The force can be adjusted appropriately.

According to the invention of claim 2, in the tension adjusting device for a saw chain according to claim 1, the adjusting handle is held by the fixed handle so as to be slidable in the screw advancing direction of the fixing screw. Since the spring that urges both handles away from each other has been inserted into the cam, the elastic effect of the compression coil spring integrates the fixed handle with the adjustment handle.Therefore, when tightening the fixing screw, you only need to hold the fixed handle to turn it. The cam surface can be brought into contact with the convex portion, improving operability.

According to a third aspect of the present invention, in the saw chain tension adjusting device according to the first or second aspect, the outer periphery of the fixed handle is formed so as to locally project from the outer periphery of the adjustment handle. As a result, when operating both handles individually, it is easy to put a finger on each handle and the operability is improved.

[Brief description of drawings]

FIG. 1 is a front view of a chain saw according to the present invention.

FIG. 2 is a partially cutaway plan view of the chain saw in a state in which tension adjustment of the saw chain is completed.

FIG. 3 is a partially enlarged view of a main part in FIG.

FIG. 4 is a front view showing a saw chain tension adjusting device with a cover removed.

FIG. 5 is a front view showing the outer appearance of the saw chain tension adjusting device.

FIG. 6 shows an adjustment handle of a saw chain tension adjusting device, (A) is a front view and (B) is a rear view.

FIG. 7 is a partially cutaway plan view of the chain saw with the fixed handle of the saw chain tension adjusting device loosened.

FIG. 8 is a partially enlarged view of a main part in FIG.

FIG. 9 is a partially cutaway plan view of the chain saw with the fixed handle of the tension adjustment device for the saw chain further loosened.

FIG. 10 is a partially enlarged view of a main part in FIG.

[Explanation of symbols]

1 ... Housing 5 ... Guide bar 9 ... Screw cylinder 11 ... convex part 13 ... Cam 14 ... Adjusting handle 21 ... Fixed handle 23 ... screw rod 24 ... Compression coil spring

Claims (3)

[Claims] 1. A guide bar of a saw chain supported by a housing so as to be slidable in a tension adjusting direction, and a cam that is superposed on the side surface of the guide bar so as to come into contact with a convex portion protruding from the side surface of the guide bar. In a saw chain tension adjusting device comprising an adjusting means for operating a cam to slide a guide bar through a convex portion, a fixing screw for fixing the guide bar to a housing, and a fixing handle for operating the fixing screw, The adjusting means includes an adjusting handle which is rotatably covered on the fixed handle, the cam is fixed to the adjusting handle, and the guide bar, the cam, and the adjusting handle are integrally formed with the housing by operating a fixing screw by the fixing handle. Saw chain tension adjusting device characterized by being tightened. 2. The saw chain tension force adjusting device according to claim 1, wherein the adjustment handle is slidably held by the fixed handle in the screw advancing direction of the fixing screw, and the two handles are separated from each other between the handles. A saw chain tension adjusting device characterized in that a biasing spring is inserted. 3. The saw chain tension force adjusting device according to claim 1 or 2, wherein the outer periphery of the fixed handle is formed so as to locally project from the outer periphery of the adjustment handle. Chain tension adjustment device.