JP3605557B2 - Cutting blade for drilling holes in walls and the like, and punching device equipped with the cutting blade - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a device for drilling a hole in a wall surface or a ceiling surface of a building as an example, and particularly in an apartment, a house, an office building, and the like in the course of construction, in performing various types of electricity, lights, telephones, gas pipes, and the like. A perforation device for forming the required opening for an indoor box.
[0002]
More specifically, the construction or building site as described above or Renovation In a middle house or the like, a box is drawn in a place concealed by a wall surface for interior or the like, into which a connection end of the wiring or piping is drawn. Normally, predetermined outlets and other switch devices are incorporated into the opening surface of this box. However, when assembling, it is necessary to open a corresponding wall surface of the box, which is hidden by a wall material or the like, in advance. , Usually to open the area corresponding to the box to the desired size Cutting blade and drilling device provided with the cutting blade Is provided.
[0003]
[Prior art]
The present invention relates to a perforation device for a wall surface or a ceiling surface or the like to meet the demand as described above. Hereinafter, a conventional type of this type of perforation device will be briefly described. In the past, using an electric drill or band saw, the band saw was drawn around after drilling to form an opening having a predetermined shape, but this method not only requires a lot of time for drilling but also In this case, a manual operation by a skilled person is required, and even in such a case, problems such as irregularities in the size of the openings and inconsistencies in the shape were unavoidable.
[0004]
Therefore, recently, a dedicated drilling tool has been developed as disclosed in Japanese Utility Model Laid-Open No. 56-113801, Japanese Patent No. 252223 (Japanese Patent Application Laid-Open No. 6-143247), Japanese Patent Application Laid-Open No. 10-156825, and the like. However, it has been found that even if these dedicated drilling tools are used, there are difficulties as described below. That is, when a device described in the above-mentioned prior publication was prototyped and actually tested, it was confirmed that the conventional punching device had the following structural defects. . First, the device of the preceding utility model will be described. This is a configuration in which a large number of cutting blades, such as knives, are protruded at a constant interval from an endless roller chain suspended on a two-axis sprocket roller, so that the wall material itself is bitten. In addition, it was found that even if the blade edge once bitten was pulled around with a roller chain, the load was too large to be practically used.
[0005]
On the other hand, the apparatus disclosed in the patent publication and the like has a cutting blade formed in the shape of an endless belt having a relatively high height, so that the bite on the wall surface is superior to the conventional tool described above. However, as the behavior of the blade after biting, as the thickness of the board layer increases (12 mm or more), the cutting blade expands in a trumpet shape toward the thick part of the wall, so that the blade cannot be pulled out at hand. It turned out that there was a real disadvantage.
According to the study of the present inventor, the reason why the cutting blade expands in a trumpet shape during drilling is that the sprocket wheel for rotating the cutting blade has a four-axis system, so the wheel itself has to be reduced in diameter, For this reason, there has been a situation in which the blade cannot be driven unless the cutting blade is extremely thin. In addition, since only one of the four axes is driven, and the shape of the hole to be cut is also substantially a quadrilateral, the endless cutting blade requires only one of the four sides during cutting. Although kept in tension, the remaining three belt-shaped cutting blades suspended on the driven sprocket become loose, and the blades meander during cutting in conjunction with the thinness of the cutting blades themselves. Or the shape of the blade is deformed in a trumpet shape, and the cutting edge cannot be pulled out after cutting.
[0006]
In this type of perforator, the above-mentioned problem is a fatal defect, and it has been desired to develop a product having high practicality in order to meet recent building specifications. That is, in the conventional drilling device, when a wall material made of gypsum board having a thickness of about 12 mm, which is a conventional architectural specification, is constituted by one piece, even if the blade edge is spread in a trumpet shape, the drilling is managed. Although it was possible, the recent demand for fire resistance enhancement and special specifications such as increasing the soundproofing effect have become common, and the gypsum board used as a wall material also needs to be used in two layers. I have. Under such circumstances, development of a new drilling tool that can smoothly accomplish its purpose regardless of whether the number of wall materials is one or two, and is not affected by the thickness of the wall materials, has been developed. Has been requested.
[0007]
By the way, in the construction specifications of the two-ply construction, sometimes these two wall materials are not in close contact with each other and a gap is formed between them. In addition to the increase in drilling, the drilling conditions also become severe, for example, the load at the time of drilling changes. Under such conditions, the tool according to the above-mentioned patent does not have a function of adjusting the protrusion of the cutting edge, and thus cannot achieve a predetermined purpose.
[0008]
This type of tool cannot cut a tough gypsum board or the like, which forms a wall surface, unless a strong driving force and a propulsive force are constantly applied to the cutting blade itself even during cutting. That is, since the conventional model uses the four-axis system as described above, the cutting blade is rotated by a relatively small diameter sprocket, and one of them is driven. The effective driving force is limited only to the sprocket wheel connected to the power source, and the other three axes are only driven, so the driven sprocket merely transmits the rotation, Could not actively provide driving or propulsive power. Therefore, in order to drive the entire cutting blade uniformly while driving it while receiving a large resistance, it was not possible to realize the initial cutting ability due to insufficient power. Furthermore, in the conventional type, it was not possible to adjust the cutting depth corresponding to the thickness of the wall surface, and the configuration was merely aimed at pushing off, so the wiring connected to the box in the opening portion And the piping may be damaged. In addition, the projections (sets) formed on the edges of the cutting blades did not exhibit the expected sharpness in the conventional type, and were not practical in this regard.
[0009]
[Problems to be solved by the invention]
Here, the present invention is a drilling device or a drilling tool for drilling a hole in an inner wall surface of a building such as a wall material or a ceiling material, and the torque of a driving source is efficiently transmitted to a cutting blade for comparison. The present invention proposes a new perforation apparatus that can perform perforation with a very small load and that does not cause the cutting blade to expand in a trumpet shape while cutting a wall material or the like as in the conventional type. In addition, even when the cutting edge of the cutting blade is worn due to use, the replacement of the cutting blade can be easily performed.Furthermore, in consideration of a device for sharpening the cutting edge, this type of cutting blade is also used. Is a revolutionary improvement that has never been seen before.
[0010]
In particular, in the present invention, a problem that could not be solved by the conventional drilling device using the above-mentioned belt-shaped cutting blade, that is, a problem that is often required in modern buildings 2 It is an object of the present invention to provide a highly practical drilling device capable of smoothly piercing a laminated wall material.
[0011]
Furthermore, the steel strip forming the cutter cannot be cut smoothly even if it is too thin or too thick, and the tests were repeated while conducting various studies to develop an appropriate cutting blade in conjunction with the configuration of the entire apparatus. As a result, a configuration that can be put to practical use has been found here, and a new punching device exhibiting a function as a general-purpose machine has been completed.
Further, when foreign matter comes into contact with the tip of the cutting blade and an excessive torque is applied to the blade, the impact is absorbed and a means for preventing damage to the cutting blade is incorporated.
In addition, in order to improve the usability as the above-described drilling device, in addition to the above-mentioned points, various allowances are taken to make the blade height suitable for the thickness and hardness of the target wall material, and the amount of protrusion of the cutting blade. Can be controlled to eliminate all of the problems of the conventional type.
[0012]
[Means for Solving the Problems]
The present inventor has worked diligently to solve the above problems, and as a result, paying attention to the fact that the shape of the opening to be cut out can achieve the purpose even if it is not necessarily a rounded rectangular shape, If the shape of the blade is an oval cross section in which a relatively large arc is connected by a straight line, it has been found that loosening or meandering of the blade caused when the cutting blade is driven can be eliminated. The present invention has been completed by noting that it is important to use a driving sprocket having a relatively large diameter as compared with the conventional type in order to maintain the driving force of the blade to the maximum.
[0013]
That is, the invention of claim 1 is a steel cutting blade that maintains a cylindrical shape in a free state, Its cutting blade At the base of Has a timing belt, and Its timing belt But A hard rubber layer that engages the peripheral surface of the sprocket pulley, It is composed of a laminate having a two-layer structure including a foamable synthetic resin layer disposed on the back surface of the hard rubber layer. And both exposed end faces of the hard rubber layer and the foamable synthetic resin layer. But Covered with silicone resin cover Have been A cutting blade characterized in that:
With such a configuration, an excessive impact torque can be absorbed and damage to the cutting blade can be prevented. Further, it is possible to prevent rubber cracking of the timing belt and extend the life of the rubber.
The invention of claim 2 is A steel cutting blade that maintains a cylindrical shape in a free state. of A laminate having a two-layer structure including a timing belt at a root portion, the timing belt engaging a peripheral surface of a sprocket pulley, and a foamable synthetic resin layer disposed on the back surface of the rigid rubber layer. And both exposed end faces of the hard rubber layer and the foamable synthetic resin layer are covered with a cover made of silicone resin. A drilling device in which a cutting blade and a driving mechanism for rotating the cutting blade are housed in a casing, wherein the driving mechanism is moved forward or backward with respect to a front surface of an opening of the casing in a direction along a rotation main axis. As well as the drive mechanism Is Two-axis sprocket pulley Have ,further The pulley Is arranged so that it can be separated or approached with respect to the other pulley. When the two pulleys are brought closer, the endless cutting blade is loosened and comes off the pulley, and when it is moved away, the cutting blade becomes Cutting blade against the two pulleys so that they are tensed But Suspension Have been A device for making holes in a wall surface or the like, characterized in that:
The invention described above adopts a driving pulley having a diameter larger than four axes as a two-axis type, without disposing the pulleys for rotating the cutting blade at four locations as in the conventional type, thereby using the driving mechanism itself. As compared with the conventional type, the simple configuration with less failures increases the driving force transmission area to the cutting blade, and at the same time, the cutting blade itself rotates without contacting the sprocket pulley Do The area is reduced so that the cutting blade does not meander or bend.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be specifically described based on the illustrated apparatus as one embodiment. FIG. 1 is a longitudinal sectional view of the present apparatus. Reference numeral 1 denotes, as an example, a cylindrical casing having an oval cross section. One side (the right side in the figure) of the casing is open, and the other side is the casing. It is closed by a side plate 3 having a relatively thick bearing portion 2 integrally formed therewith. A shaft tube 4 is attached to a center portion of a bearing portion 2 formed in the casing 1 outward (to the left in the figure), and a spring 4a is contracted in the shaft tube to thereby reduce the main shaft. 5 is always given a tendency to protrude in the direction indicated by the arrow in the figure. One end 5a of the main shaft 5 is made to pass through the inside of the barrel 4 and then protrude out of the casing. A drive source 6 such as an electric drill is set at the shaft end. A cutting blade drive mechanism 7 described below is mounted on an end 5b on the casing side, which is the other end of the main shaft 5.
In addition, as for the shape of the opening surface of the casing 1, only the upper part can be formed into a flat straight line as shown by a chain line in FIG. 2 (see reference numeral 1c in the figure). In this case, when the device is used to make a hole in a wall or the like, the device itself can be easily set along a score line drawn on the wall, and thus positioning is easy.
Hereinafter, details of the driving mechanism will be described. The mechanism 7 includes a frame 8 having a planar shape that fits inside the casing 1, two plates 9, 9 of the same shape that sandwich the frame from front and rear, and screws 8 a for integrally assembling them. And the whole drive mechanism is mounted so as to be able to move forward or backward within the casing.
The main shaft 5 is passed through the center of the frame 8, and the end 5 b of the main shaft is fixed to the outer contact plate 9 located on the opening end side of the casing 1, and the drive is performed. In the mechanism 7, a drive gear 10 is attached to a portion of the main shaft 5 exposed in the frame 8, and the transmission gear 12 is engaged with the gear via a transmission shaft 11 disposed in parallel with the main shaft. Match. On the other hand, another support shaft 13 is mounted above the inside of the frame 8 located on the opposite side of the gear 12 with the main shaft 5 as the center, and the main shaft is connected to the main shaft as shown in FIG. When a sliding block 14 movable in a direction perpendicular to the sliding block 14 is fitted with an appropriate clearance, thereby moving the sliding block in the vertical direction in the drawing, a sprocket pulley described below fixed to the tip of the support shaft 13. 14 is also mounted so as to move up and down as the block slides. The sliding block 14a is moved up and down via an adjusting screw 14b shown in FIG. 2. When the screw is turned, an elongated hole 1b formed at the top of the casing 1 is used. Use
[0016]
Also, a cutting blade driving pulley having the following configuration is attached as a part of the driving mechanism. That is, pulleys 14 and 15 for driving the cutting blades are fixed to the respective extended ends of the transmission shaft 11 and the support shaft 13 which are mounted symmetrically about the main shaft 5 in the figure while maintaining a fixed relationship. Then, the endless cutting blade 16 is suspended from these pulleys.
[0017]
Hereinafter, the mounting state of the cutting blade and the timing belt will be described. As shown in FIGS. 1 to 3, a timing belt 17 having an uneven portion formed inwardly is attached to the root portion of the blade, and a gear-shaped member provided on the peripheral surface of the pulleys 14 and 15 at the uneven portion. Are formed so that the concaves and convexes mesh with each other.
Hereinafter, a state in which the endless cutting blade, the timing belt, and the belt are attached to the root of the endless cutting blade will be described in detail. First, the configuration of the endless cutting blade 16 will be described. The cutting blade itself has a thickness of 100 to 200 μm, and is made of a strip steel or stainless steel having spring properties, for example, while being formed of stainless steel having a Vickers hardness of about 500, The timing belt 17 provided at the base of the cutting blade is formed by foaming a hard rubber layer 17a having irregularities to be engaged with the peripheral surface of the sprocket pulley and a neoprene resin layer laminated on the back surface of the rubber layer 17a. And the conductive synthetic resin layer 17b. That is, after forming a timing belt with a laminated body composed of the hard rubber layer and the foamable resin layer, the timing belt is firmly bonded to the root of the cutting blade using an appropriate adhesive such as a silicone resin. (See reference numeral 17c). It is preferable that the exposed end face of the laminate is covered with a cover 17c made of a silicone resin as shown in FIG. 7, so that the laminate may be peeled off even when an excessive torque is applied. There is no.
[0018]
On top of that, even when excessive torque is applied to the cutting blade by interposing a foamable synthetic resin sponge layer such as neoprene resin on the lower surface of the hard rubber layer having tooth type irregularities as the intermediate layer of the timing belt, In addition, the temporary overload is absorbed by the sponge layer torsion, so that damage to the cutting blade and breakage of the timing belt can be prevented, so that the object can be perforated without being damaged.
As is clear from FIG. 7 for explaining the timing belt, the upper and lower surfaces of the sprocket pulley 15 are respectively provided with flange plates for preventing the sprocket pulley 15, and the diameter of the upper plate 15a is larger than the diameter of the lower plate 15b. Even if it is made slightly smaller, it is easy to replace the cutting blade.
[0019]
Next, the saw blade 16a formed on the leading edge of the cutting blade will be described. As is clear from FIGS. 5 and 8 (a) to 8 (c), a mountain-shaped saw blade is formed on the edge of the cutting blade, and a pyramid-shaped projection 16b is formed on the antinode of the saw blade. Alternatively, it is preferable to provide a bottom-like projection 16c, whereby the sharpness of the cutting blade is maintained sharply, and at the same time, the cutting speed of the cutting blade itself is increased, and at the same time, the service life is prolonged. When the projections 16a or 16b are inclined surfaces having slightly different angles on the left and right, the longer inclined tips are directed in a direction such that they protrude in the direction of travel of the cutting blade when cutting. Is allowed.
[0020]
By the way, as shown in FIGS. 5 to 7, as an example, the endless cutting blade made of stainless steel having the above-mentioned thickness and having resiliency is rich in elasticity itself. This keeps it cylindrical as shown in FIG. After the cutting blade in such a state is suspended on the sprocket pulleys 14 and 15 as shown in FIGS. 1 to 3, one of the pulleys, that is, the support shaft 13 of the pulley 14 located above in the drawing is moved to the sliding block 14a. When the cutting blade is separated from the lower pulley 15 through the cutting blade, the cutting blade gradually changes to a tensioned state, and the tension reaches a limit state. When the timing belt 17 at the root of the cutting blade 16 is tensioned in this manner, the belt comes into close contact with and engages with the pulleys 14, 15, so that the rotation of the pulley is transmitted to the cutting blade via the belt. Is done.
[0021]
Incidentally, since a timing belt 17 having a two-layer structure composed of a hard rubber layer and a foamable resin layer is adhered to the root of the endless cutting blade 16, the gear-shaped irregularities 17a provided on the rubber layer are described above. By engaging with the pulleys 14 and 15 and rotating in a certain direction by the driving force of the pulleys, the rotation of the main shaft 5 is strongly transmitted in the direction indicated by the arrow in the figure.
[0022]
As described above, in the present invention, two relatively large diameter pulleys are used as sprocket pulleys for driving the cutting blade, and as a result, the expansion or suspension of the steel strip forming the cutting blade is smooth. Now you can do it. That is, since the cutting blade itself is suspended in a form in which two arcs are connected by a straight line, there are only two sides of the straight line that do not come into contact with the sprocket. Since it can be enlarged to the corresponding extent, the driving force transmission surface becomes larger than that of the 4-axis system, and as a result, not only can the cutting blade itself be prevented from twisting and meandering during cutting, but also a large torque can be obtained. .
Moreover, the adoption of a large-diameter rotary pulley enables the thickness of the cutting blade itself to be increased. That is, since a relatively thick one having a thickness of 100 to 200 μm can be used, it has been found that the wall has a good bite and the durability is also excellent.
[0023]
As shown in FIG. 1, the cutting edge 16a, which is the tip of the endless cutting blade, is disposed toward the opening end 1a of the casing 1, and the opening end guides the entry and exit of the cutting edge. A pulley cover 21 is attached inside the outer guide 20. As an example, the cover is screwed via a support rod 22 implanted in the side plate 3 of the casing 1, and the cutting blade 16 enters and exits between the cover 21 and the outer guide 20. A gap as much as possible is formed. The pins 20a protruding from the surface of the outer guide 20 are used for positioning when drilling holes in a wall surface or the like, and the pins 21a protruding from the surface of the pulley cover 21 are used for similar purposes. It is also used as a pull-out pin for taking out the cutting chips from the outside.
[0024]
In the present invention, in order to adjust the protruding height of the cutting blade, more specifically, the length of the cutting edge protruding from the open end of the casing 1, near the shaft end on the drive side of the main shaft 5, as shown in FIG. A plurality of resin or metal stop collars 23 having different heights l (lowercase letters) as shown are prepared, and these colors are appropriately selected. (In some cases, two pieces having a low height are used at the same time) and fitted between the shaft end 5a of the main shaft 5 and the barrel 4 to adjust the protruding length of the main shaft 5, whereby In this case, the effective protruding amount of the cutting blade can be adjusted. Reference numeral 24 denotes a retaining ring used when attaching or detaching the stop collar. The distance L shown in FIG. 1 indicates the effective protrusion amount of the blade when the stop collar is fitted, and the protrusion length can be set arbitrarily according to the number and the height of the collar.
[0025]
When a predetermined hole is to be drilled in the inner wall of a building using the drilling device having the above-described structure, first, if a predetermined location or a drilling location is unknown, an appropriate magnetic sensor or the like is used. Is determined by using the position search device of (1), and a perforated surface (see FIG. 3) located on the front side of the apparatus is pressed toward the perforated portion by placing it on the wall surface to be drilled. In this way, the outer guide 20 protruding from the front surface of the apparatus and the guide pins 20a and 21a protruding from the surface of the pulley cover 21 pierce the pressed wall surface, whereby the perforation position is stably held. You. Next, when a rotational force is applied to the main shaft 5 via a driving source 6 such as an electric drill fitted to one end 5a of the driving main shaft 5 of the present apparatus, a driving gear 10 attached to the main shaft is accordingly provided, The transmission gear 12 meshing with the gear rotates, and the sprocket pulley 15 mounted on the same shaft as the gear further rotates. Since an endless cutting blade 16 is suspended between the sprocket pulley and the driven sprocket pulley 14 provided in parallel with the pulley, the rotation of the driving pulley is provided on the cutting blade. The data is transmitted via the timing belt 17. After the cutting blade 16 is driven in this manner, when the main shaft 5 is pushed in while holding a handle such as an electric drill as the drive source, the entire drive mechanism 7 shown in FIG. The blade is sequentially extruded from the surface, and the blade cuts the wall material while biting into the wall surface. The amount of protrusion of the cutting blade is determined by the height (l) of the stop collar 23 fitted into the neck of the main spindle 5, and the use of a low-height collar increases the amount of protrusion L (see FIG. 1). In this way, the protrusion amount according to the thickness of the wall surface to be opened can be arbitrarily set.
[0026]
Next, when the cutting blade 6 is worn due to use and becomes poor in sharpness as a result or is damaged for some reason, it is necessary to replace it with a new one. . As described above, when a cutting operation is performed by the cutting blade 16 by a normal operation, the cutting blade itself is suspended by the two upper and lower sprocket pulleys 14 and 15 while always being kept in tension. Then, when the main shaft 5 is driven via the electric drill 6, and the drill is grasped and pressed against the wall surface, the cutting blade 16 moves forward and cuts the wall body automatically.
[0027]
As described above, in the normal use state, of the two upper and lower sprocket pulleys 14 and 15 that suspend the cutting blade 16, the support shaft of one pulley 14 is orthogonal to the axis in the drive mechanism 7. The slide screw 14b is attached to a sliding block 14a that moves in the direction of movement, and an adjusting screw 14b for sliding the block up and down is screwed into the block. While the cutting blade 16 is in the cutting state, the block is positioned upward in the figure by the screw 14b, so that the sprocket pulley is placed at the uppermost position via the shaft 13 fitted in the block. Therefore, this pulley and the other pulley whose axial position is fixed are located farthest from each other, so that the cutting blade 16 suspended between the two pulleys keeps the tension state. I have.
[0028]
By the way, when replacing the cutting blade 16, the adjusting screw 14b screwed into the sliding block 14a is loosened and the flock is slid downward in the drawing, whereby the space between the sprockets 14 and 15 is reduced. This causes the cutting blade 16 to become loose. That is, the timing belt 17 formed at the base of the blade is removed from the tooth form of the sprocket, taken out, and replaced with a new cutting blade.
[0029]
Next, the case where foreign matter other than the wall material is present in the wall when the cutting blade is in a normal cutting state will be described. As described above, the timing belt 17 attached to the root portion of the cutting blade 16 has the sponge resin layer 17b interposed below the hard rubber engagement portion 17a having the tooth shape. When an excessive torque is generated due to biting into the board, the shock is absorbed, and at the same time, the rotation is stopped by transmitting the torque to the motor on the driving side.
[0030]
【The invention's effect】
Unlike the conventional four-axis pulley system, the apparatus of the present invention drives the cutting blade with a relatively large-diameter two-axis sprocket pulley, so the area where the cutting blade is in contact with the pulley is small. Compared with the four-axis type, it is much larger, and therefore a large driving force can be obtained. Also, during cutting, the cutting blade is not in contact with the pulley only on the left and right sides, so the cutting blade itself may be formed thick, and during cutting, the blade may There is no danger of biting obliquely, and it is always pushed vertically, resulting in a sharp cut.
In addition, when the cutting blade is replaced, the driving pulley itself is moved to the position to loosen the cutting blade itself, so that the blade can be easily replaced.
[0031]
Further, a sponge layer is interposed as an intermediate layer of the timing belt that transmits a driving force to the cutting blade. In other words, a sponge layer made of synthetic resin is interposed below the hard rubber belt having the tooth mold. Therefore, when an excessive load is applied to the blade itself, the sponge layer is twisted to reduce the impact, and at the same time, the rotation of the blade is stopped.
[0032]
Furthermore, when a pyramid-shaped or ship-bottom projection is formed on the antinode of the saw blade, which is the tip of the cutting blade, the projection bites into the material to be cut during cutting, and the cut edge becomes beautiful. In addition to the finish, it has the effect of increasing the cutting speed.
[0033]
Furthermore, when a pyramid-shaped or ship-bottom projection is formed on the antinode of the saw blade, which is the tip of the cutting blade, the projection bites into the material to be cut during cutting, and the cut edge becomes beautiful. In addition to the finishing, the cutting speed is increased, and effects such as extending the life of the blade are exhibited.
[Brief description of the drawings]
FIG. 1 is a vertical side view of the present apparatus.
FIG. 2 is a transverse sectional view taken along line XX of FIG.
FIG. 3 is a transverse sectional view taken along line YY of FIG. 1;
FIG. 4 is a front view of the present apparatus.
FIG. 5 is a side view of a cutting blade in the present apparatus.
FIG. 6 is a sectional view taken along line ZZ in FIG. 5;
FIG. 7 is an enlarged cross-sectional view of a part at a root portion of the cutting blade.
8A is a partially enlarged plan view of a saw blade portion formed at the tip of a cutting blade, FIG. 8B is a sectional view of the same, and FIG. 8C is an enlarged sectional view showing another embodiment.
FIG. 9A is a side view of the stop collar, with a part cut away. (B) is a front view of the stop ring, and (c) is a longitudinal sectional view of the same.
[Explanation of symbols]
1: Casing
2: Bearing part
3: Side plate
4: Shaft tube
5: Spindle
6: Drive source
7: Drive mechanism
8: Frame
9: This plate
10: drive gear
11: conduction axis
12: conduction gear
13: Support shaft
14: Sliding block
15: Pulley
16: Cutting blade
17: Timing belt
20: Outside guide
21: Pulley cover
22: pointing rod
23: Stop color
24: Ring for retaining

Claims (2)

A steel cutting blade to maintain the cylindrical in a free state, has a timing belt to the root portion of the cutting edge, and a hard rubber layer which engages the peripheral surface of the timing belt sprocket pulley, the hard rubber together they are composed of a laminate of two-layer structure consisting of a foamable synthetic resin layer disposed on the rear surface of the layer, both the exposed end faces of the hard rubber layer and the foamed synthetic resin layer is coated with a silicon resin cover cutting edge, characterized in that there. A steel cutting blade that maintains a cylindrical shape in a free state, has a timing belt at the root of the cutting blade , and the timing belt engages with a peripheral surface of a sprocket pulley; and a hard rubber layer. The hard rubber layer and the foamable synthetic resin layer have both exposed end faces covered with a silicone resin cover, and are formed of a laminate having a two-layer structure including a foamable synthetic resin layer disposed on the back surface of the layer. A drilling device in which a cutting blade and a driving mechanism for rotating the cutting blade are housed in a casing, wherein the driving mechanism is moved forward or backward with respect to a front surface of an opening of the casing in a direction along a rotation main axis. with mounting as possible, the drive mechanism comprises a two-shaft sprocket pulley, arranged so as to be able to further one of said pulleys, moved away or closer to the other pulley Te, wherein the closer the two pulleys out from the pulley loose cutting blades endless cutting blade relative to the two pulleys so that the cutting blade is tension and away is suspended A device for making holes in walls and the like.

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