JPH11138339A - Hand cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hand cutter with an automatic belt adjustment mechanism, simplified and compact structure, which is cheap in cost and easy in inspection and maintenance of a belt. SOLUTION: A cutter head 25 is provided with a belt adjustment device which is located at an offset position outside of a belt 12 winding a driving pulley 7a and a driven pulley 11 and adjusts the tension of the belt 12 in parallel with an axis connecting rotating shafts of the driving pulley 7a and the driven pulley 11 by a straight line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hand cutter used for cutting secondary concrete products and the like, and more particularly, to a hand provided with a belt adjusting device for adjusting the tension of a belt around which a driving pulley and a driven pulley are wound. About cutter.

[0002]

2. Description of the Related Art As a prior art having a belt adjusting device for adjusting the tension of a driving belt of a hand cutter, for example,
Japanese Utility Model Application Laid-Open No. 63-198502 will be described with reference to FIG. The prime mover 50 is mounted on the main body 51. An arm 53 is attached to the main body 51. This arm 5
A cutter 54 is rotatably attached to the distal end of the cutter 3. The motor 50 extends along the arm 53.
And a belt 59 for transmitting the power to the cutter 54. The studs 69, 70 of the main body 51 are passed through the slots 67, 68 of the arm 53, and a nut (not shown) is screwed onto the studs 69, 70 to attach the arm 53 to the main body 51. A screw rod member 72 extending in the longitudinal direction of the arm 53 is attached to the main body 51. The distal end portion 78 of the threaded rod member 72 is supported movably in the longitudinal direction with respect to a guide portion 77 provided on the arm 53, and a nut member 80 is screwed into an intermediate portion of the threaded rod member 72, and the guide portion 77. The spring seat member 81 is movably attached to the threaded rod member 72 adjacent to. A spring 82 is provided between the nut member 80 and the spring seat member 81 so that the spring seat member 81 is brought into contact with the guide portion 77, and the arm is constantly pressed forward.
The arm 53 is provided with means 84 and 85 for positioning the nut member 80 at a position where the nut 53 is maintained at a predetermined length. An output shaft 55 of the prime mover 50 has a drive pulley 55 rotatably mounted on the output shaft 55. 57 is a cutter 54
The driven pulley 58 is rotatably mounted on the shaft 57. The driving pulley 55 and the driven pulley 58 are wound around a belt 59, and the tension of the belt 59 is adjusted by the above-described means.

[0003]

However, the belt adjusting means for adjusting the belt tension described in Japanese Utility Model Application Laid-Open No. 63-198502 is a belt 59 for winding the driving pulley 55 and the driven pulley 58. It is located inside. Since the space inside the belt 59 is narrow, and the size of the inside of the belt is determined by the diameter of the driving pulley 55 and the driven pulley 58, the belt adjusting means depends on the size of the inside of the belt. It was not always possible to provide a belt adjusting means which is easily required to be easily adjusted from the outside with a size which is easily required for maintenance. For this reason, the work of adjusting the belt tension is performed with a tool such as a wrench inside the belt 59, so that the adjustment work is troublesome and the maintainability is poor. Also, the belt tension is not constant, and when the belt tension is weak, there is a problem that the belt slips and the driving force is reduced, or the belt is damaged. Furthermore, if the belt is overstretched, there is a problem in durability of the bearing and the like due to premature wear and damage of the belt and excessive thrust force acting on the rotating shaft of the pulley.

The present invention focuses on the above-mentioned conventional problems, and makes it possible to easily adjust the belt tension from the outside of the belt, and to apply an automatic belt adjusting mechanism, a driving pulley and a driven pulley which constantly apply a constant tension. The belt adjustment device is arranged at a position offset to the outside of the belt around which the belt is wound, so that the structure is simplified, the size of the cutter head in the width direction is reduced, the size is reduced, and the cost is low and the belt inspection and maintenance is performed. It is an object of the present invention to provide a hand cutter which is easy to perform.

[0005]

In order to achieve the above object, a first invention of a hand cutter according to the present invention comprises a drive source such as an engine and a motor, and a drive connected to an output shaft of the drive source. A driving device including a pulley, a belt, and the like, a driven pulley that transmits power from the driving device,
A hand cutter having a cutter blade for rotating via a gear and a belt adjusting device for adjusting a tension of a belt around which the drive pulley and the driven pulley are wound; And a belt that adjusts the tension of the belt 12 at a position offset to the outside of the belt 12 around which the belt 12 is wound, and in parallel with an axis connecting the respective rotation axes of the driving pulley 7a and the driven pulley 11 with a straight line. In this configuration, the adjusting device is provided in the cutter head 25. According to the above configuration, a belt adjustment device that adjusts the belt tension in a position offset to the outside of the belt, and in parallel to an axis that connects the respective rotation axes of the driving pulley and the driven pulley with a straight line. Since the belt adjusting device is provided, it is possible to manufacture a belt adjusting device that is suitable for small to large hand cutters having different V-belt sizes. Further, even when the distance between the respective rotation axes of the driving pulley and the driven pulley is short, or when the diameters of the driving pulley and the driven pulley are small, the belt adjusting device is disposed at a position where it is easy to maintain and has a necessary size. be able to. Further, since the belt adjusting device can be disposed at a position independent of the driving pulley, the driven pulley, and the belt, assemblability and maintainability are improved.

According to a second aspect of the present invention, in the configuration of the first aspect, the belt adjusting device is housed in a cutter head, and the belt 12 is arranged so as to be adjustable from outside the cutter head 25. . According to the above configuration, the operation of adjusting the belt tension can be performed quickly and easily.

According to a third aspect of the present invention, in the configuration of the first or second aspect, the belt adjusting device is located above or below the drive belt 12 in a side view of the hand cutter, and in a top view of the hand cutter. The configuration is such that it is arranged to overlap with the drive belt 12. According to the above configuration, the size of the hand cutter in the width direction can be reduced to be compact, and the tension adjustment of the drive belt can be easily performed.

According to a fourth aspect of the present invention, in the configuration according to any one of the first to third aspects, the belt adjusting device urges the driving belt 12 with a constant spring force by rotation of the adjusting bolt 20. The belt tension is maintained at a constant value and the tension is automatically adjusted. According to the above configuration, the tension of the belt is always automatically adjusted to a constant appropriate value by a constant spring force, thereby preventing early wear of the belt due to excessive application of excessive tension when adjusting the belt by the operator. In addition, the durability life of the belt can be extended, and the work efficiency of the hand cutter can be improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a hand cutter according to the present invention will be described below with reference to FIGS. First, FIG.
As shown in FIG. 1, the hand cutter 30 includes a drive source 1 such as an engine and an electric motor. The power output from the output shaft of the driving source 1 described later is transmitted to a driving device 40 including a pulley, a belt, and a gear (not shown),
The driving device 40 drives the cutter blade 5 to rotate. Reference numeral 6 denotes a safety cover that covers the cutter blade 5. A drive case 10 is detachably attached to a lower side surface of the drive source 1 shown in FIGS. The output shaft 1a of the drive source 1 is inserted into an insertion hole provided in the drive case 10, and the coaxial 1a protrudes from the side surface of the drive case 10. This output shaft 1a has
Two drive pulleys 7a and 7b are rotatably attached via a coupling (not shown). Drive pulley 7a
Is wound around a driven pulley 11 and a belt 12 rotatably attached to a shaft 11 a attached to the cutter head 25. The power of the driving source 1 is transmitted from the output shaft 1a to the driven pulley 11 via the driving pulley 7a and the belt 12, and the cutter blade 5 is driven to rotate about the shaft 5a as a rotation fulcrum. This belt 12
The tension adjustment of the spring 2 will be described later in detail.
3 and so on.

Below the driving pulley 7a and the belt 12, there is disposed a dust suction device 4 comprising a dust suction fan 4b of a hand cutter. The dust suction device 4 is rotatably attached to the output shaft 1a of the drive source 1 via a coupling (not shown). A driven pulley 2 having a smaller diameter than the driving pulley 7b of the dust suction device 4 is rotatably attached to the drive case 10. This drive pulley 7b
And the driven pulley 2 are wound around a belt 9.
Reference numeral 8 denotes an idler pulley for adjusting the tension of the belt. 4a
Is a dust discharge port for sucking dust generated at the time of cutting a secondary concrete product or the like by the cutter blade 5 from a dust suction port provided at a lower portion of the safety cover with the dust suction fan 4b and discharging the dust to a dust bag (not shown).

The safety cover 6 is integrally formed with a cutter head 25 for rotatably supporting the cutter blade 5. Stud bolts 15 and 16 shown in FIG. 4 are attached to the cutter head 25. These stud bolts 15, 16 are inserted into elongated holes 10d, 10e provided in the drive case 10 shown in FIG. 3, respectively, and fastened with nuts as shown in FIG. The spring 23 of the belt adjusting device shown in FIG. 4 comes into contact with a concave portion 10f provided in the drive case 10 shown in FIG. Thereby, the spring 23 presses the drive case 10. As shown in FIG.
Is slidable within the range of the elongated holes 10d and 10e with respect to the cutter head 25, so that the drive case 10 slides and the belt 12 is automatically tensioned and adjusted by a belt adjusting device described later. Has become. The belt adjusting device including the adjusting bolt 20, the spring 23, etc.
It is arranged outside the belt 12 and parallel to the belt 12.

Next, FIG. 5 of the Z view of FIG. 2 will be described. Components having the same reference numerals as those in FIG. 2 have the same functions, and thus description thereof will be omitted. Adjustment bolt 20 for belt adjustment device
Can be rotated by a tool from the front of the hand cutter at a position below the driving device 40.

FIG. 6 shows the belt adjusting device.
The support member 21 is fastened to the cutter head 25 by a nut 22. The support member 21 is threaded. When the adjustment bolt 20 is screwed into the support member 21, the tip of the bolt 20 pushes the end boss 23 a of the spring 23, and the spring 23 is disposed between the end boss 23 a and the drive case 10. Is pressed to push the drive case 10 leftward in the figure. This drive case 1
0 is pressed, the drive pulley 7a shown in FIG.
Thus, the tension of the belt 12 around which the driven pulley 11 is wound is kept constant, and the tension can be automatically adjusted even if the belt 12 is stretched. Since the tension of the belt 12 is determined by the force of the spring 23, the tension is set to a spring having a predetermined wire diameter and length. FIG. 7 (a),
(B), (c) has shown the Y view of FIG. In the case of FIG. 7A, the head of the adjustment bolt 20 is rotatable with a tool such as a hexagonal wrench.
In the case of (b), it is made rotatable by a minus driver, and in the case of FIG. 7 (c), it is made rotatable by a plus driver. FIG. 8 shows another embodiment of the belt adjusting device. In this embodiment, the spring 23 and the end boss 23a shown in FIG. 6 are eliminated, and the adjusting bolt 20a is screwed into the support member 21 to be used.
By pressing the drive case 10 with the tip of the bolt, the tension of the belt 12 can be adjusted as in FIG. In this case, the bolts may be rotated so that the operator can check the belt tension and adjust the belt tension so that the belt is properly tensioned. Except for this, they have the same functions as those described in FIG.

As described above, according to the hand cutter of the present invention, the adjustment device of the belt around which the driving pulley and the driven pulley are wound is provided at a position offset to the outside of the belt and at the same time as the driving pulley and the driven pulley. Since the rotation axes of the drive pulleys were arranged in parallel to the axis connecting them with a straight line,
It is possible to manufacture a belt adjusting device adapted to small to large hand cutters having different V-belt sizes. Further, even when the distance between the rotating shafts of the driving pulley and the driven pulley is short, or when the diameters of the driving pulley and the driven pulley are small, the belt adjusting device can be disposed at a position where maintenance is easy. Further, the belt adjusting device can be arranged at a required size at a position independent of the driving pulley, the driven pulley, and the belt.
The assemblability and maintainability are improved.

Furthermore, since the belt adjusting device is arranged on the front side of the cutter blade and from the outside of the belt so as to be adjustable, the belt tension adjusting operation can be performed quickly and easily.

Further, the belt adjusting device is disposed at a lower position or an upper position of the driving belt and overlapped with the driving belt when the hand cutter is viewed from above, so that the width of the hand cutter in the width direction can be reduced. As a result, the drive belt tension can be easily adjusted.

The belt adjusting device automatically adjusts the tension of the driving belt by holding the tension at a constant value by rotating the adjusting bolt to rotate the spring, and the tension of the belt is adjusted by the spring force. Since the tension is always automatically adjusted to a constant appropriate value, it is possible to prevent the belt from being worn early due to excessive tension applied by the operator when the belt is adjusted, and to extend the durability life of the belt. At the same time, the work efficiency can be improved by the hand cutter.

[Brief description of the drawings]

FIG. 1 is a side view of a hand cutter according to the present invention.

FIG. 2 is an explanatory view of a drive device of the hand cutter.

FIG. 3 is a diagram showing a state in which a drive case is mounted on a drive source.

FIG. 4 is a side view in which a belt adjusting device is mounted on the head cutter.

FIG. 5 is a Z view in FIG. 2;

FIG. 6 is a diagram illustrating a belt adjustment device.

7A and 7B are views in the Y direction of FIG. 6; FIG. 7A shows a configuration in which the head shape of the adjustment bolt is made rotatable with a tool such as a hexagon wrench; FIG. The shape of the head is made rotatable with a flathead screwdriver.
In the figure, the head shape of the adjustment bolt is made rotatable with a Phillips screwdriver.

FIG. 8 is a diagram illustrating another example of the belt adjustment device.

FIG. 9 is a diagram illustrating a belt adjusting device for a conventional hand cutter.

[Explanation of symbols]

 Reference Signs List 1 drive source 5 cutter blade 7a drive pulley 10 drive case 10d long hole 10e recess 11 driven pulley 12 belt 20, 20a adjustment bolt 21 support member 22 nut 23 spring 25 cutter head

Claims (4)

[Claims] 1. A drive source such as an engine or a motor, a drive unit connected to an output shaft of the drive source, the drive unit including a drive pulley and a belt, and a driven pulley transmitting power from the drive unit to rotate. Having a cutter blade to make
In a hand cutter provided with a belt adjusting device for adjusting the tension of a belt around which the drive pulley and the driven pulley are wound, a belt (12) around which the drive pulley (7a) and the driven pulley (11) are wound Belt adjustment that adjusts the tension of the belt (12) in a position offset to the outside of the belt and parallel to the axis connecting the rotation axes of the driving pulley (7a) and the driven pulley (11) with a straight line. A hand cutter comprising a device provided on a cutter head (25). 2. The hand cutter according to claim 1, wherein
A hand cutter, wherein the belt adjusting device is housed in a cutter head, and the belt (12) is arranged so as to be adjustable from the outside of the cutter head (25). 3. The hand cutter according to claim 1, wherein the belt adjusting device is located above or below the drive belt (12) in a side view of the hand cutter, and
A hand cutter, wherein the hand cutter is arranged so as to overlap with the drive belt (12) when viewed from above the hand cutter. 4. The hand cutter according to claim 1, wherein the belt adjusting device biases the belt (12) with a constant spring force by rotation of an adjusting bolt (20). A hand cutter characterized in that the tension of the belt is maintained at a constant value and the tension is automatically adjusted.