JPH0436794Y2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) This invention relates to a circular cutter in which a circular blade is rotatably attached to a blade attachment portion of the handle.

(Prior Art) Conventionally, as this type of circular cutter, there is one disclosed in European Patent Publication No. 0027492. As shown in FIG. 7, this circular cutter has a protective disk 52 and a circular blade 53 stacked on one side of the end of a long plate-shaped handle 51. The mounting screw 54 is inserted so as to be substantially orthogonal to the section. Then, by loosely fitting an annular disc spring 55 to the end of the mounting screw 54 protruding to the other end of the handle 51 and then screwing the tightening nut 56, the disc 52 and the circular blade 53 are attached to the handle. 5
It is installed on 1.

In the above-described circular cutter, the head 54a of the mounting screw 54 presses the side surface of the circular blade 53 due to the action of the disc spring 55 to apply a frictional force, and this frictional force is controlled by the amount of tightening of the tightening nut 56. It is configured to be adjusted. Therefore, by appropriately changing the tightening amount of the tightening nut 56 when using the circular cutter, the frictional force applied to the circular blade 53 can be adjusted, and furthermore, by changing the frictional force, the circular blade 53 can tighten the workpiece. The amount of rotation is adjusted to improve cutting quality.

(Problem to be solved by the invention) However, in the above rotary cutter, the circular blade 53
Since frictional force is applied in the direction along the rotation center of the circular blade 53, the pressing force is directly applied to the circular blade 53, causing the center of the circular blade 53 to bend inward, causing the workpiece to meander. In some cases, the correct cut may not be made.

Further, when the tightening nut 56 is strongly tightened on the mounting screw 54, the circular blade 53 is compressed between the nut 56 and the head 54a of the screw 54, and is easily fixed completely. Therefore, the circular blade 53 becomes unable to rotate, and cutting is likely to become impossible. Therefore, fine adjustment of the nut 56 requires careful attention, is time consuming, and is troublesome to handle.

Structure of the invention (means for solving the problem) In order to solve the above problem, in this invention, a circular blade 1 is attached to the blade attachment part 3 formed on the handle 1.
In the circular cutter rotatably attached to 4,
The brake drum 12 is attached to the side surface of the circular blade 14 and rotates integrally with the circular blade 14, and the pressing member 18 is capable of being pressed against the brake drum 12 in a direction substantially perpendicular to the center of rotation of the circular blade 14. It is something.

(Operation) By bringing the pressing member 18 into pressure contact with the brake drum 12, the amount of rotation of the circular blade 14 is adjusted. Moreover, since the pressing member 18 is applied in a direction substantially perpendicular to the rotation center of the circular blade 14, the circular blade 14 is not bent.

(First Embodiment) A first embodiment of this invention will be described below with reference to FIGS. 1 to 3.

Reference numeral 1 denotes a handle, which is composed of a grip part 2 and a blade attachment part 3 formed at its front end. A support tube 4 having a short cylindrical shape extending in the vertical direction is formed at the front end of the blade attachment portion 3, and a support hole 5 is formed in the center of the support tube 4.
It is becoming.

Reference numeral 6 denotes a semi-oval-shaped mounting recess formed at the front end of the grip portion 2 of the handle 1, and the entire outer periphery of the mounting recess is slightly raised to form a stepped portion 7. In addition, the second
As shown in the figure, the stepped portion 7 is provided with three locking holes 8 having a rectangular planar shape at the rear end and on both left and right sides. A rotation permissive groove 9 extending in the width direction is transparently provided in approximately the center of the mounting recess 6, and a pair of semi-cylindrical holding parts 10 are protruded from the front and rear sides of the permissible groove 9. . Note that reference numeral 11 denotes a pair of left and right fitting protrusions that are formed protrudingly from the rear portion of the holding portion 10.

Reference numeral 12 denotes an annular brake drum that is loosely fitted around the outer periphery of the support cylinder 4, and has three support protrusions 13 spaced apart at equal angles in the circumferential direction on its upper surface.
is formed. 14 is a circular blade placed on the brake drum 12, and has three fitting holes 15 through which the support projections 13 of the brake drum 12 can fit. The support protrusion 13 of the brake drum 12 is inserted into the fitting hole 15 of the circular blade 14, so that the circular blade 14 rotates integrally with the brake drum 12 without being able to rotate relative to the brake drum 12. In particular, as shown in FIG.
A tightening nut 1 is attached to the end of this setscrew 17 that is inserted from above 4 and protrudes from the lower surface of the blade attachment part 3.
7d are screwed together. This set screw 17 consists of a head portion 17a and a shaft portion 17b, and a step portion 17c that can be inserted into the central hole 16 of the circular blade 14 is formed in the middle portion thereof.

Reference numeral 18 denotes a pressing member that is fitted into the holding portion 10 of the mounting recess 6 so as to be movable in the front-rear direction of the handle 1, and includes a semicircular arc-shaped pressure contact portion 19 formed at the front and a shaft formed at the rear. 20. The pressure contact portion 19 of the pressing member 18 has a pressure contact surface 19a on its front surface, and a threaded portion 20a is threaded on the rear portion of the shaft portion 20. Further, an adjustment nut 21 is disposed within the rotation allowance groove 9, and extends rearwardly through the shaft portion 20 of the pressing member 18 through both the holding portions 10 and the adjustment nut 21.
Then, by rotating the nut 21, the threaded portion 20a of the pressing member 18 is moved back and forth,
The pressing force applied by the pressing member 18 to the brake drum 12 can be adjusted, and its specific operation will be described later.

Reference numeral 22 denotes a protective member superimposed on the upper surface of the blade attachment portion 3, and includes an annular portion 23 with an open rear end.
, a pair of arm portions 24 extending toward the rear of the handle 1 from both ends of the opening, and an annular engagement portion 25 formed at the rear end of these arm portions 24 . A locking hole 26 is formed in the center of each locking portion 25, and the fitting protrusion 1 of the mounting recess 6 is inserted into the locking hole 26.
1 is fitted, the base end portion of the protection member 22 is held immovably within the attachment recess 6. In particular, as shown in FIG. 3, when the circular blade 14 is attached to the support cylinder 4 of the blade attachment part 3, the protection member 22 is attached between the lower surface of the circular blade 14 and the upper surface of the blade attachment part 3, The support tube 4 is positioned within the ring portion 23.

Reference numeral 27 denotes a cover that covers the mounting recess 6 and is composed of a half-oval-shaped closing part 28 and an abutting part 29 that protrudes downward from the lower surface of its outer periphery. It is in contact with the upper surface of the stepped portion 7 of the mounting recess 6 . Further, a protrusion hole 30 extending in the width direction is formed in the front central portion of the closing portion 28, and a portion of the adjustment nut 21 protrudes upward from the protrusion hole 30. Three locking legs 31 are formed in the abutting portion 29 at positions corresponding to the locking holes 8 of the mounting recess 6, and these locking legs 31 are fitted into the locking holes 8 of the mounting recess 6. has been done. As a result, cover 2
7 is attached to the attachment recess 6 so as not to come off in a natural state.

When using the circular cutter configured as described above, first rotate the adjustment nut 21 as appropriate depending on the type of the object to be cut, and adjust the pressing force of the pressing member 18 against the circular blade 14 as follows. . Second
As shown in the figure, when the adjusting nut 21 is rotated in the direction of arrow P, the threaded portion 20a of the pressing member 18 moves forward within the holding portion 10. Due to this movement, the pressure contact portion 19 of the pressing member 18 also advances, and the pressure contact surface 19a
is pressed against the brake drum 12. Then, when the circular blade 14 rotates, frictional resistance is applied to the brake drum 12 in a direction substantially perpendicular to the rotation center of the circular blade 14 in accordance with this pressure contact force, and the circular blade 14 also rotates in a controlled state. The sharpness improves. This pressure contact force is adjusted by appropriately changing the amount of rotation of the adjustment nut 21 to change the position of the pressing member 18 in the direction of the brake drum 12.
Pressing surface 19a of pressing member 18 and brake drum 1
This is done by changing the pressure contact area with the rear outer peripheral surface of No. 2.

Then, the circular blade 14 is moved along the cutting direction while pressing the circular blade 14 against the object to be cut, with the handle 1 lying at an appropriate inclination angle with respect to the object to be cut.

On the other hand, when the adjusting nut 21 is rotated in the direction opposite to the direction of arrow P in FIG. 2, the threaded portion 20a of the pressing member 18 moves rearward within the mounting recess 6 of the handle 1. Due to this movement, the pressure contact portion 1 of the pressing member 18
9 also moves backward, and the pressure contact surface 19a touches the brake drum 12.
The pressure force applied to the rear outer circumferential surface is small. Therefore, the circular blade 14 rotates in a relaxed manner.

In this embodiment, the frictional force is applied in a direction substantially perpendicular to the rotation center of the circular blade 14. Therefore, unlike conventional products, the circular blade 14 is rarely compressed and completely fixed, and almost never becomes unrotatable. Also, circular blade 1
Since no pressure force is applied directly to 4,
The circular blade 14 does not bend, and accurate cutting can be performed without the circular blade 14 meandering during cutting.

(Second Embodiment) Next, a second embodiment of this invention will be described with reference to FIG.

In this embodiment, the rear ends of the arm portions 24 of the protection member 22 are connected, and a mounting portion 35 that is fitted into the rear portion of the mounting recess 6 is provided at this connection portion.
Then, the V-shaped leaf spring 36 attached to the back surface of the front end of the mounting portion 35 is pressed against the front side surface of the second stepped portion 37 at the rear end of the mounting recess 6, and the protection member 22 is biased forward. It is mounted in the mounting recess 6. The circular blade 14 is always located inward from the annular portion 23 of the protection member 22, and when cutting, the circular blade 14
3 is pressed against the object to be cut, the leaf spring 36 bends and the annular portion 23 moves backward. Therefore, circular blade 1
4 is configured to rotate while a part thereof is in contact with the surface of the object to be cut.

Even in this configuration, since the frictional force on the circular blade 14 is applied in a direction substantially perpendicular to the rotation center of the circular blade 14, there is no difference in operation and effect compared to the first embodiment. .

(Third Embodiment) Next, a third embodiment of this invention will be described with reference to FIGS. 5 and 6.

In this embodiment, as shown in FIG.
A locking hole 38 is transparently provided at the rear end of the blade attachment part 3,
The entire front edge is a locking surface 3 with a sharp uneven surface.
It has become 9. The pressing member 18 includes a pressure contact portion 19 having a semicircular arc-shaped pressure contact surface 19a, an arm portion 42 extending rearward from the rear end of the pressure contact portion 19, and a pivot portion formed approximately in the center of the arm portion 42 in the length direction. 41, and the arm portion 42 is further formed with an adjustment portion 43 that protrudes downward from its rear end. The bolt 40 is inserted into the pivot portion 41 and the insertion hole 3a of the blade attachment portion 3, so that the entire pressing member 18 rotates relative to the handle 1.

In particular, as shown in FIG. 5, the adjustment part 43 is inserted into the locking hole 38 of the blade attachment part 3, and has a locking protrusion on its inner surface that is locked to the locking surface 39 of the locking hole 38. A portion 43a is formed, and an end portion of the adjustment portion 43 projects from the lower surface of the blade attachment portion 3 through the locking hole 38, and this projecting portion serves as an operating portion 43b.
When the operating portion 43b is pressed, the locking protrusion 43a climbs over the convex portion 39a of the locking surface 39, and the adjacent recess 3
9b, and the position within the locking hole 38 is changed in stages.

Further, as shown in FIG. 6, when the operating portion 43b of the pressing member 18 is pushed in the direction of arrow Q, the pressing member 18 rotates around the bolt 40, and the locking protrusion 43a of the pressing member 18 locks. One of the recesses 39b of the hole 38
It is locked inside the piece. Then, the pressing surface 19a of the pressing member 18 is strongly pressed against the outer peripheral surface of the brake drum 12, and the circular blade 14 rotates in a controlled manner. Moreover, if the operating portion 43b of the pressing member 18 is pushed in the direction opposite to the direction of the arrow Q and the locking protrusion 43a is moved into another recess 39b, the pressing surface 19a is applied to the outer circumferential surface of the brake drum 12. The pressure contact force becomes small. Therefore, the circular blade 14 rotates with less control. In this way, the force with which the pressing member 18 presses against the brake drum 12 can be adjusted in stages, and the sharpness of the circular blade 14 can be changed.

44 is a mounting recess formed at the front end of the grip part 2 of the handle 1, and the mounting recess 44 is connected to the communication path 44a.
It communicates with the blade attachment part 3 via. Mounting recess 4
4 and the communication path 44a, the rear end portion of the arm portion 24 and the engaging portion 25 of the protection member 22 are fitted, respectively.
The protection member 22 has a bolt 4 inserted into the locking hole 26.
It is fixed by 5. 46 is the locking hole 38
It is an arc-shaped guide section extending in the width direction in front of the arm section 42 of the pressing member 18 at its upper end.
The bottom surfaces are in contact with each other. This guide part 4
6 prevents the lower surface of the arm portion 42 of the pressing member 18 from coming into direct contact with the surface of the blade attachment portion 3;
This allows the pressing member 18 to rotate smoothly.

In this case, the pressing force of the pressing member 18 against the brake drum 12 can be adjusted by pressing the operating portion 43b of the pressing member 18 to appropriately change the position within the locking hole 38, thereby rotating the pressing member 18. This is done by changing the position and, in turn, changing the pressing area between the pressing surface 19a of the pressing member 18 and the outer peripheral surface of the brake drum 12.

In the third embodiment, the outer circumferential surface of the brake drum 12 and the pressure contact surface 19a of the pressing member 18 may be formed with mountain-shaped notches so that they can mesh with each other.

Effects of the invention As detailed above, with this invention, frictional force is applied in a direction almost perpendicular to the rotation center of the circular blade, so it is extremely rare for the circular blade to become completely fixed and unable to rotate. Since no pressing force is applied directly to the circular blade, it is possible to prevent the circular blade from bending and meandering during cutting, thereby improving cutting performance and operability.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing the first embodiment of this invention, Fig. 2 is a partial plan view of the same, and Fig. 3 is a second embodiment of the invention.
4 is an exploded perspective view showing a second embodiment of this invention, FIG. 5 is an exploded perspective view showing a third embodiment of this invention, and FIG. 6 is a partial view of the same. The plan view and FIG. 7 are cross-sectional views showing a conventional example. Handle...1, Blade mounting part...3, Brake drum...
...12, Circular blade...14, Pressing member...18.

Claims (1)

[Scope of claim for utility model registration] 1. The circular blade 1 is attached to the blade attachment part 3 formed on the handle 1.
4 is rotatably attached to the circular cutter, the circular cutter is attached to the side surface of the circular blade 14, and the circular cutter 14 is
A circular cutter comprising: a brake drum 12 which rotates integrally with the brake drum 12; and a pressing member 18 which can be pressed against the brake drum 12 in a direction substantially perpendicular to the center of rotation of a circular blade 14. 2. The brake drum 12 is loosely fitted around the outer periphery of the support tube 4 formed on the blade attachment part 3, and the pressing member 18 is mounted on the pressing member 18 in a direction substantially perpendicular to the center of rotation of the circular blade 14. The circular cutter according to claim 1, characterized in that an adjustment nut 21 for movement is screwed together. 3. Utility model registration claim 2, characterized in that the brake drum 12 has a support protrusion 13 protruding from its upper surface that can fit into a fitting hole 15 formed through the circular blade 14. Circular cutter described in. 4. Claims for Utility Model Registration characterized in that the pressing member 18 has a semi-circular arc-shaped pressing part 19 at its front part, and a shaft part 20 having a threaded part 20a screwed into an adjustment nut 21 at its rear part. The circular cutter according to item 2. 5. The pressing member 18 has a semicircular arc-shaped pressure contact portion 19 at its front portion, an arm portion 42 extending rearward from the rear end of the pressure contact portion 19, and a pivot portion formed approximately at the center of the arm portion 42 in the length direction. 41. The circular cutter according to claim 1 of the utility model registration claim.