Blade body adapter and chisel blade body

Abstract

[Problem] To facilitate removal of a chisel blade body attached to an impact tool while preventing the blade body from falling out. [Solution] This blade body adapter is for attaching a chisel blade body to an impact tool by means of a tool attachment portion in which a through-hole orthogonal to a central axis and a central hole that reaches the through-hole along the central axis from a front side end surface are formed, the blade body adapter comprising: a main body in which a tapered hole complementary to an inclined surface of a tang of the blade body and a tapered hole complementary to a tapered portion of the tool attachment portion are formed; a spring of which forward movement with respect to the main body is restricted; and a screw member in which a screw that engages with a screw hole in the tang is formed and which is urged backward by the spring. The adapter is configured such that a through-hole in the main body orthogonal to the central axis between the two tapered holes communicates with the front side end of the tapered hole on the rear side.

Description

Blade body adapter and chisel blade body

[0001] This invention relates to a technique for attaching a chisel blade body to an impact tool or the like.

[0002] When performing carving, cutting of a workpiece such as wood is performed using a carving knife or a chisel. However, when using a carving knife or a chisel which is a manual tool, it is necessary to apply force to push the cutting edge forward, and it is not always easy to produce a carved object. Therefore, as an instrument for more easily performing carving, electric carving machines that reciprocate a carving blade electrically have been variously developed (see, for example, Patent Document 1) and are on the market.

[0003] In such an electric carving machine, the output for reciprocating the carving blade is small, and the cutting ability is insufficient for producing large carved objects such as Buddha statues and decorations of temple buildings. On the other hand, as a tool with a large reciprocating output, impact tools using pneumatic pressure called breakers and hammer chisels are known. Therefore, it has been proposed to attach a chisel blade (blade body) with good cutting performance and high strength to an impact tool (see Patent Document 2).

[0004] In order to realize attaching and using a blade body to an impact tool as a practical means, in Patent Document 2, by transmitting an impact force to the blade body through an inclined shape surface formed in the blade body insertion part and a tapered hole complementary to the inclined shape surface, deformation of the blade body is suppressed. And by setting the inclination angles of the inclined shape surface and the tapered hole within a predetermined range, it has also been proposed to suppress the detachment of the blade body and facilitate the removal of the blade body.

[0005] Japanese Patent Application Laid-Open No. 8-156499 Japanese Patent Application Laid-Open No. 2019-119004

[0006] However, even if the inclination angles of the inclined shape surface and the tapered hole are appropriately set, due to long-term use, the inclined shape surface and the tapered hole may bite strongly, and it may become difficult to remove the blade body.

[0007] The present invention has been made to solve the above-described conventional problems, and an object thereof is to provide a technique for more easily removing a blade body while suppressing the detachment of the blade body when attaching and using a chisel blade body to an impact tool.

[0008] To achieve at least part of the above objectives, the present invention can be realized in the following forms, examples of applications, or applications.

[0009] [Application Example 1] A blade adapter for attaching the blade of a chisel, which cuts a workpiece by pushing the cutting edge forward, to an impact tool via a tool mounting portion, comprising: a substantially cylindrical adapter body having a front tapered hole complementary to the inclined surface formed in the grommets of the blade, and a rear tapered hole complementary to the tapered portion provided at the front end of the tool mounting portion; a spring housed inside the adapter body and restricted from moving forward relative to the adapter body; and a blade mounting screw formed on the rear end face of the grommets that engages with a blade-side screw hole formed therein, wherein the spring is used to attach the adapter A blade adapter comprising: a screw member housed inside the adapter body and configured to be biased rearward relative to the main body; an adapter through hole formed in the adapter body at a position between the front tapered hole and the rear tapered hole, perpendicular to the central axis of the adapter body, and configured to communicate with the front end of the rear tapered hole; and the tool mounting portion having a tool mounting through hole perpendicular to the central axis of the tool mounting portion, and a tool mounting central hole extending from the front end face of the tool mounting portion to the tool mounting through hole along the central axis.

[0010] In this application example, the impact force applied to the blade adapter is transmitted to the blade via the inclined surface formed at the base of the blade and the inner surface of the front tapered hole which is complementary to the inclined surface, thereby suppressing deformation of the blade due to the impact force. Furthermore, since the blade is biased toward the blade adapter, by increasing the taper angle of the inclined surface formed at the base of the blade and the front tapered hole to a degree that makes it easy to remove the blade from the blade adapter, it is possible to make it easier to remove the blade from the blade adapter while suppressing the blade from falling out of the blade adapter.

[0011] Furthermore, since the adapter through-hole, formed perpendicular to the central axis of the adapter body, communicates with the front end of the rear tapered hole, air supplied through the tool mounting through-hole and the central hole of the tool mounting section is released to the outside through the adapter through-hole. Cooling is performed by this air supplied from the tool mounting section and released to the outside, so the temperature rise in the area where impact force is transmitted can be suppressed.

[0012] [Application Example 2] A blade adapter according to Application Example 1, wherein the screw member has a substantially disc-shaped flange portion whose outer diameter is set to be larger than the outer diameter of the spring, a substantially cylindrical columnar portion provided on the front side of the flange portion and whose outer diameter is set to be smaller than the inner diameter of the spring, and a screw portion provided on the front side of the columnar portion and on which the blade mounting screw is formed, the outer diameter of which is set to be smaller than the inner diameter of the spring, and the columnar portion has a screw member through hole formed perpendicular to the central axis of the columnar portion, and the columnar portion and the flange portion have a screw member central hole formed along the central axis, reaching from the rear end face of the flange portion to the screw member through hole.

[0013] This configuration allows for the creation of a blade adapter with fewer components.

[0014] [Application Example 3] A blade adapter according to Application Example 1, wherein the screw member comprises a blade mounting screw, a bolt on which a member joining screw for forming the screw member is formed, a substantially cylindrical columnar portion having a joining screw hole that engages with the member joining screw and whose outer diameter is set to be smaller than the inner diameter of the spring, and a substantially disc-shaped flange portion provided on the rear side of the columnar portion and whose outer diameter is set to be larger than the outer diameter of the spring, wherein the columnar portion has a screw member through hole formed perpendicular to the central axis of the columnar portion at a position rearward from the joining screw hole, and the columnar portion and the flange portion have a screw member central hole formed along the central axis, reaching from the rear end face of the flange portion to the screw member through hole.

[0015] With this configuration, even if a bolt breaks due to impact force applied during cutting, it can be repaired by replacing the bolt.

[0016] [Application Example 4] A blade adapter according to Application Example 1, wherein the screw member has a screw portion on which the blade mounting screw is formed, the outer diameter of which is set to be smaller than the inner diameter of the spring, and a flange-shaped portion provided on the rear side of the screw portion portion, which is substantially disc-shaped, the outer diameter of which is set to be larger than the outer diameter of the spring, and which has two engaging surfaces formed parallel to the central axis and facing each other at a distance wider than the outer diameter of the screw portion, and a gripping groove wider than the distance between the two engaging surfaces is formed at the front end of the tapered portion.

[0017] This application example simplifies the configuration of the blade adapter and suppresses damage to the screw component.

[0018] [Application Example 5] The blade adapter according to any one of Application Examples 1 to 4, wherein a rotation suppression groove is formed on the front end face of the adapter body, and a rotation suppression portion provided on the blade body that protrudes rearward from the neck of the blade body contacts it on the inner surface.

[0019] With this configuration, the rotation of the blade body is restricted when the rotation-restricting part of the blade body contacts the rotation-restricting groove, thereby preventing the blade body from rotating during cutting.

[0020] [Application Example 6] A chisel blade that can be attached to a blade holder according to any one of Application Examples 1 to 4, wherein the mortise is formed in a tapered shape complementary to the front tapered hole formed in the adapter body, and a screw hole that engages with the blade mounting screw formed in the screw member is formed on the rear end face of the mortise.

[0021] According to this application example, since the joint is formed with a tapered shape complementary to the front tapered hole formed in the blade adapter of the blade holder, the blade can be attached to the blade holder in a more appropriate state. In addition, since a screw hole is formed in the screw member that engages with the blade mounting screw formed therein, the blade can be biased toward the blade adapter by screwing the blade mounting screw into the screw hole, thereby preventing the blade from falling out.

[0022] [Application Example 7] A chisel blade that can be attached to the blade holder described in Application Example 5, wherein the mortise is formed in a tapered shape complementary to the front tapered hole formed in the adapter body, a screw hole is formed on the rear end face of the mortise that engages with the blade mounting screw formed in the screw member, and the blade is provided with a rotation suppression part that protrudes rearward from the neck of the blade and is configured to contact the inside of a rotation suppression groove formed in the adapter body.

[0023] According to this application example, it becomes possible to attach the blade to the blade holder in a more appropriate state, and the blade can be biased toward the blade adapter, thereby preventing the blade from falling off. Furthermore, since the rotation suppression part contacts the inside of the rotation suppression groove formed in the adapter body, the rotation of the blade is restricted, thus preventing the blade from rotating during cutting.

[0024] [Application Example 1] A chisel using the blade of the chisel described in Application Example 6, comprising a handle and a blade mounting part configured to attach the blade and screwed to the handle, wherein the blade mounting part has a mounting part body having a blade mounting part having a tapered hole formed therein that is complementary to the tapered shape formed in the grommets of the blade, and a substantially cylindrical tubular part provided behind the blade mounting part, a spring housed inside the tubular part and whose forward movement relative to the mounting part body is restricted, and a screw member housed inside the mounting part body having a screw formed therein that engages with the screw hole formed on the rear end face of the grommets, and configured to be biased rearward relative to the mounting part body by the spring, the chisel comprising

[0025] [Application Example 2] A chisel using the blade of the chisel described in Application Example 7, comprising a handle and a blade mounting part configured to attach the blade and screwed to the handle, wherein the blade mounting part has a mounting part body having a blade mounting part having a tapered hole formed therein that is complementary to the tapered shape formed in the grommets of the blade, and a substantially cylindrical tubular part provided behind the blade mounting part, a spring housed inside the tubular part and whose forward movement relative to the mounting part body is restricted, and a screw member housed inside the mounting part body having a screw formed therein that engages with the screw hole formed on the rear end face of the grommets and is configured to be biased rearward relative to the mounting part body by the spring, and a rotation suppression groove is formed on the inner surface of the front end face of the blade mounting part, which is provided on the blade and contacts the rotation suppression part.

[0026] According to Application Examples 1 and 2, the blade of a chisel attached to an impact tool using a blade adapter can be the same as the blade of a chisel used as a hand tool. Therefore, it becomes possible to use a sharp blade used for chisels attached to an impact tool without having to prepare a separate blade for attachment to the impact tool.

[0027] An explanatory diagram showing the configuration of the blade holder in the first embodiment of the present invention. An explanatory diagram showing the configuration of the blade holder in the first embodiment. An explanatory diagram showing the state in which a blade is attached to the blade holder. An explanatory diagram showing the state in which the blade holder is attached to an impact tool. An explanatory diagram showing the configuration of a chisel using the blade in the first embodiment. An exploded perspective view showing the configuration of the blade holder in the second embodiment of the present invention. An exploded perspective view showing the configuration of the blade holder in the third embodiment of the present invention. A cross-sectional view showing the state in which a blade having a rotation suppression member is attached to the blade holder. An explanatory diagram showing the configuration of a chisel using a blade similar to that of the third embodiment. An exploded perspective view showing the configuration of the blade holder in the fourth embodiment of the present invention.

[0028] The embodiments for carrying out the present invention will be described below in the following order. A. First Embodiment: A1. Configuration of the blade holder: A2. Attachment of the blade to the blade holder: A3. Attachment of the blade holder to the impact tool: A4. Configuration of the chisel as a manual tool: B. Second Embodiment: C. Third Embodiment: C1. Configuration of the blade holder: C2. Attachment of the blade to the blade holder: C3. Configuration of the chisel as a manual tool: D. Fourth Embodiment: E. Modifications:

[0029] A. First Embodiment: A1. Configuration of the Blade Mounting Device: Figures 1 and 2 are explanatory diagrams showing the configuration of the blade mounting device 10 in the first embodiment of the present invention. Figure 1 shows the blade mounting device 10 in an exploded perspective view, and Figure 2 shows the blade mounting device 10 in a cross-sectional view. Figure 2 shows the blade mounting device 10 cut by a plane passing through the central axis C, indicated by the dashed line in Figure 1, and perpendicular to the plane of paper in Figure 1.

[0030] The blade mounter 10 of the first embodiment is a device for attaching the blade of a chisel to an impact tool such as a breaker. The specific manner in which the blade is attached to the blade mounter 10 and the specific manner in which the blade mounter 10 is attached to the impact tool will be described later.

[0031] The blade is attached from the front, and the blade holder 10 is attached to the impact tool at the rear. In this specification and the present invention, "front" or "front" refers to the direction from the impact tool toward the blade, and "rear" or "rear" refers to the direction opposite to the front, that is, the direction from the blade toward the impact tool.

[0032] As shown in Figures 1 and 2, the blade mounter 10 comprises a tool mounting section 100 and a blade adapter 200. The blade mounter 10 is formed by assembling the tool mounting section 100 and the blade adapter 200 along a central axis C. The central axis C is the central axis of the entire blade, blade mounter 10, and impact tool, as well as the central axis of the blade mounter 10, the tool mounting section 100 and the blade adapter 200 that constitute the blade mounter 10, and the various parts 210, 220, and 230 (described later) that constitute the blade adapter 200.

[0033] The tool mounting portion 100 has a base end portion 110 provided on the rear side, a shaft portion 130 provided on the front side, and a flange-shaped portion 120 provided between the base end portion 110 and the shaft portion 130. The base end portion 110 is a solid member and has a cylindrical columnar portion 111 and a tapered portion 112 provided on the rear side of the columnar portion 111, with its outer diameter decreasing towards the rear. The flange-shaped portion 120 is a solid disc-shaped member with an outer diameter larger than that of the base end portion 110 and the shaft portion 130.

[0034] The shaft portion 130 has a main shaft portion 131 and a tapered portion 132 provided on the front side of the main shaft portion 131, which has a frustoconical shape (tapered shape) whose outer diameter decreases towards the front. A through hole 139 (tool mounting through hole) is formed at the rear end of the shaft portion 130, perpendicular to the central axis C. In addition, the shaft portion 130 has a central hole 138 (tool mounting central hole) along the central axis C, which extends from the front end face of the shaft portion 130 to the through hole 139.

[0035] Furthermore, the main shaft portion 131 has four flat sections 135 parallel to the central axis C in order to suppress the rotation of the tool mounting portion 100 (blade holder 10) around the central axis C. Therefore, the outer shape of the main shaft portion 131 is generally that of a cylinder cut by four flat sections. Note that if the rotation of the tool mounting portion 100 (blade holder 10) around the central axis C can be suppressed by the configuration of the impact tool, etc., the formation of the flat sections 135 can be omitted.

[0036] The blade adapter 200 comprises a substantially cylindrical adapter body 210, a spring 220, and a screw member 230. As shown in Figure 2, the blade adapter 200 is formed by inserting the spring 220 and the screw member 230 into the adapter body 210 in that order from the rear. In this state, the spring 220 and the screw member 230 are housed inside the adapter body 210.

[0037] A rear tapered hole 219 is formed on the rear side of the adapter body 210, with its inner diameter increasing towards the rear. The taper angle and the diameter at the rear end of the rear tapered hole 219 formed in the adapter body 210 and the tapered portion 132 of the tool mounting portion 100 (shaft portion 130) are set to be approximately the same. As a result, the tapered portion 132 of the tool mounting portion 100 engages with the rear tapered hole 219 of the adapter body 210, fixing the adapter body 210 and the tool mounting portion 100 together.

[0038] Here, the taper angle refers to the angle formed between the surface of the tapered portion or tapered hole and the central axis C in a plane passing through the central axis C of the tapered portion or tapered hole. As is clear from this, the tapered hole and the tapered portion that engages with the tapered hole have an inclined shape with respect to the central axis C, and the tapered hole and the tapered portion have complementary shapes to each other.

[0039] The front side of the adapter body 210 also has a front-side tapered hole 218, whose inner diameter widens towards the front. As will be described in detail later, the taper angle and the diameter of the front end of this front-side tapered hole 218 are set to be approximately the same as the grommets, so that the grommets of the tapered blade body engage with it.

[0040] As described above, a parallel hole 217 with a constant inner diameter and centered on the central axis C is formed between the rear tapered hole 219 and the front tapered hole 218 in the adapter body 210, communicating with these tapered holes 219 and 218, respectively. The adapter body 210 also has a through hole 216 (adapter through hole) formed at the position of the parallel hole 217, that is, between the front tapered hole 218 and the rear tapered hole 219, perpendicular to the central axis C.

[0041] The inner diameter of the parallel hole 217 is set to be the same as the inner diameter of the rear tapered hole 219 at its front end. Also, the inner diameter of the front tapered hole 218 at its rear end is set to be smaller than the inner diameter of the parallel hole 217 (i.e., the inner diameter of the rear tapered hole 219 at its front end). As a result, a step is formed at the front end of the parallel hole 217 due to the difference between the inner diameter of the parallel hole 217 and the inner diameter of the front tapered hole 218 at its rear end.

[0042] As shown in Figures 1 and 2, the screw member 230 has a substantially disc-shaped flange portion 231 provided on the rear side, a threaded portion 233 provided on the front side, and a substantially cylindrical columnar portion 232 provided between the flange portion 231 and the threaded portion 233. A through hole 239 (screw member through hole) is formed in the columnar portion 232, perpendicular to the central axis C. In addition, the screw member 230 (flange portion 231 and columnar portion 232) has a central hole 238 (screw member central hole) along the central axis C, which extends from the rear end face of the flange portion 231 to the through hole 239.

[0043] The outer diameter of the threaded portion 233 is set to be smaller than the inner diameter at the rear end of the front tapered hole 218 formed in the adapter body 210, and the outer diameter of the columnar portion 232 is set to be larger than the inner diameter at the rear end of the front tapered hole 218. Furthermore, the outer diameter of the flange portion 231 is larger than the outer diameter of the columnar portion 232 and slightly smaller than the inner diameter of the parallel hole 217 formed in the adapter body 210. By setting the outer diameters of the flange portion 231, the columnar portion 232, and the threaded portion 233 in this way, the threaded member 230 is positioned such that its rear end (the rear end of the flange portion 231) is located in front of the rear tapered hole 219, and its front end (the front end of the threaded portion 233) is located in front of the rear end of the front tapered hole 218, that is, inside the front tapered hole 218.

[0044] The spring 220 is a compression coil spring whose outer diameter is set smaller than the inner diameter of the parallel hole 217 formed in the adapter body 210 and whose inner diameter is set larger than the outer diameter of the columnar portion 232 of the screw member 230. The spring 220 with its outer and inner diameters thus set is arranged to be sandwiched between a step formed at the front end of the parallel hole 217 of the adapter body 210 and the flange-like portion 231 of the screw member 230 in the direction of the central axis C. Then, the forward movement of the spring 220 is restricted by the step formed at the front end of the parallel hole 217.

[0045] A2. Attachment of the cutting blade to the cutting blade holder: FIG. 3 is an explanatory diagram showing a state where the cutting blade 800 is attached to the cutting blade holder 10. In FIG. 3, the cutting blade holder 10 is shown in a cross-sectional view similar to that in FIG. 2. On the other hand, the cutting blade 800 is shown in a partial cross-sectional view in which a part of its rear side is cut in the same manner as the cutting blade holder 10. <000,0092>The cutting blade 800 of the chisel shown in FIG. 3 is similar to a general cutting blade of a chisel in that it has an ear 810, a neck 820, and a shank 830. However, in the cutting blade 800 in the first embodiment, the shank 830 is formed in a tapered shape whose outer diameter decreases toward the rear, and a screw hole 839 (cutting blade side screw hole) is formed from the rear end face of the shank 830 toward the front.

[0047] As described above, the taper angle of the shank 830 is set to be substantially the same as the taper angle of the front taper hole 218 formed in the adapter body 210. On the other hand, the outer diameter at the front end of the shank 830 is set to be slightly smaller than the inner diameter at the front end of the front taper hole 218. Therefore, the shank 830 bites into the front taper hole 218 with the rear end face of the neck 820 being separated from the front end face of the adapter body 210. Thereby, the cutting blade 800 is fixed to the cutting blade holder 10, and the impact force applied from the impact tool to the cutting blade holder 10 is transmitted to the cutting blade 800 via the inner surface of the front taper hole 218 formed in the adapter body 210 and the outer surface of the shank 830.

[0048] Thus, the impact force applied from the impact tool to the blade holder 10 is transmitted to the blade body 800 through the inclined surfaces (the inner surface of the front tapered hole 218 and the outer surface of the insert 830) formed in a complementary taper shape (inclined shape). These complementary inclined surfaces are more easily made larger in area than the rear end surfaces of the neck 820 and the insert 830. Therefore, it becomes easier to widen the impact force transmission surface and suppress deformation of the blade body 800 due to the impact force.

[0049] As shown in FIG. 3, the screw hole 839 formed in the insert 830 is formed to mesh with the screw portion 233 of the screw member 230. By screwing the screw member 230 with the screw portion 233 meshed with the screw hole 839 of the insert 830, the screw member 230 moves forward with respect to the adapter body 210. As a result, the spring 220 sandwiched between the flange-shaped portion 231 provided on the screw member 230 and the step at the front end of the parallel hole 217 of the adapter body 210 is compressed.

[0050] The repulsive force of the compressed spring 220 biases the screw member 230 rearward. When the screw member 230 is biased rearward, the blade body 800 is biased rearward, that is, toward the adapter body 210, through the screw hole 839 that meshes with the screw portion 233. By biasing the blade body 800 toward the adapter body 210 (blade adapter 200) in this way, the blade body 800 is prevented from falling off the blade adapter 200.

[0051] Incidentally, the smaller the taper angle of the front tapered hole 218 of the insert 830 and the adapter body 210, the stronger the blade body 800 and the adapter body 210 are fixed, but it becomes difficult to remove the blade body 800 from the blade adapter 200. On the other hand, the larger the taper angle of the front tapered hole 218 of the insert 830 and the adapter body 210, the easier it is to remove the blade body 800 from the blade adapter 200, but the fixing between the blade body 800 and the blade adapter 200 becomes weaker, and there is a risk that the blade body 800 may come off the blade adapter 200 during use.

[0052] However, in the first embodiment, by providing the blade adapter 200 with an adapter body 210 having a tapered hole (front tapered hole 218) complementary to the grommet 830, a screw member 230 having a screw portion 233 that engages with a screw hole 839 formed in the grommet 830, and a spring 220 that biases the screw member 230 rearward relative to the adapter body 210, it is possible to prevent the blade 800 from falling out of the blade adapter 200.

[0053] Therefore, even when the taper angle of the recess 830 and the front tapered hole 218 is increased to the extent that it is easy to remove the blade body 800 from the blade body adapter 200, the blade body 800 is prevented from falling out of the blade body adapter 200. This prevents the blade body 800 from falling out of the blade body adapter 200 and makes it easier to remove the blade body 800 from the blade body adapter 200.

[0054] Furthermore, in the blade holder 10 of the first embodiment, the two members that are fixedly attached to each other and transmit impact force (i.e., the tool mounting portion 100 and the adapter body 210, and the adapter body 210 and the blade 800 830) are fixed by interlocking complementary tapered surfaces. This makes it possible to suppress damage to the blade holder 10 caused by the impact force applied from the impact tool compared to when it is fixed using screws or the like.

[0055] A3. Attachment of the blade mounter to the impact tool: Figure 4 is an explanatory diagram showing the blade mounter 10 attached to the impact tool 900. Figure 4 shows the blade mounter 10 attached to the impact tool 900, as well as the blade 800 attached to the blade mounter 10. As can be seen from Figure 4, the blade adapter 200 that constitutes the blade mounter 10 is configured to attach the blade 800 to the impact tool 900 via the tool attachment portion 100.

[0056] As shown in Figure 4, the impact tool 900 comprises a piston 910, a cylinder 920, a cap 930, and a spring 940. The cylinder 920 houses the piston 910 and the flange-like portion and base end provided on the rear side of the chisel. Here, the chisel is a tip tool commonly used in impact tools 900, and the external shape of the tool mounting portion 100 of the blade holder 10 is similar to the shape of the rear end of the chisel.

[0057] The front end of the cylinder 920 has an enlarged inner diameter to accommodate the flange portion 120 of the tool mounting portion 100, and a male thread is formed on its outer surface. The bottomed cylindrical cap 930 has a female thread that engages with this male thread, and the cap 930 is fixed to the cylinder 920 by screwing it on. The cap 930 also has a through hole 939 for passing the shaft portion 130 of the tool mounting portion 100. The spring 940 contacts both the flange portion 120 and the cap 930. As a result, the tool mounting portion 100 is biased toward the rear.

[0058] When the impact tool 900 is activated, the compressed air, which is its power source, causes the piston 910 to reciprocate along the central axis C. When the piston 910 moves forward, the front end of the piston 910 comes into contact with the base end 110 of the tool mounting portion 100, and an impact force is applied to the tool mounting portion 100. This impact force is transmitted to the blade 800 via the blade holder 10, causing cutting to be performed by the blade formed on the blade 800.

[0059] Although not shown in the diagram, in the impact tool 900, compressed air is usually introduced into the space (front end space) AF formed by the front end of the cylinder 920 and the cap 930 in order to prevent dust from entering the impact tool 900 through the gap between the shaft portion 130 and the through hole 939 provided in the cap 930.

[0060] As described above, the through hole 139 formed in the shaft portion 130 of the tool mounting portion 100 is formed at the rear end of the shaft portion 130 near the flange portion 120. Therefore, when the flange portion 120 is positioned in the front end space AF, the through hole 139 is located within the front end space AF. Consequently, the front end space AF of the impact tool 900 is connected to the outside via a flow path (air flow path) formed by this through hole 139, the central hole 138 formed in the shaft portion 130, the rear tapered hole 219 formed in the adapter body 210, the central hole 238 and through hole 239 formed in the screw member 230, and the parallel hole 217 and through hole 216 formed in the adapter body 210. As a result, the compressed air introduced into the front end space AF flows through the air flow path and is released to the outside, as indicated by the white arrows.

[0061] In the first embodiment, the adapter body 210 and the blade body 800 are fixed by interlocking the front tapered hole 218 and the joint 830, which are formed in complementary inclined shapes. When an impact force is applied to the contact area between the front tapered hole 218 and the joint 830, friction occurs between the front tapered hole 218 and the joint 830, causing the temperature of the adapter body 210 and the joint 830 to rise.

[0062] However, in the first embodiment, since compressed air flows through the air passage, the adapter body 210 and the fitting 830 are cooled, and the temperature rise of the adapter body 210 and the fitting 830 can be suppressed. Similarly, in the first embodiment, the tool mounting portion 100 and the adapter body 210 are fixed by interlocking complementary tapered surfaces, so the temperature rise on these tapered surfaces can also be suppressed.

[0063] Furthermore, in the blade mounter 10 of the first embodiment, through holes 139 and a central hole 138 that form air passages in the tool mounting portion 100 are formed in the shaft portion 130 on the front side of the flange portion 120. As a result, an air passage connecting to the front end space AF is formed without providing an opening on the rear end face (impact tool 900 side) of the tool mounting portion 100, so that the base end portion 110 can be made solid. By making the base end portion 110 solid in this way, deformation of the base end portion 110 due to impact force applied to the base end portion 110 from the piston 910 can be suppressed.

[0064] Furthermore, from the standpoint of forming an air passage in this manner, the outer diameter of the flange portion may be reduced to the extent that it can receive the repulsive force of the spring 220, and a gap may be provided between the flange portion and the parallel hole 217. Alternatively, a groove may be formed in the flange portion that spans both front and back, or a projection extending outward from the columnar portion may be provided instead of the flange portion, and the repulsive force of the spring 220 may be received by the projection. In this way, it is possible to form an air passage even if the formation of through holes and central holes provided in the screw member is omitted. However, in order to allow for smoother front and back movement of the screw member, it is preferable to provide a through hole 239 and a central hole 238 in the screw member 230, as in the first embodiment.

[0065] A4. Configuration of a Chisel as a Hand Tool: Figure 5 is an explanatory diagram showing the configuration of a chisel 30 using the blade body 800 in the first embodiment. The chisel 30 as a hand tool comprises a blade body 800, a blade mounting part 300, a bolster 31, a handle 32, and a ferrule 33. The blade mounting part 300 of the chisel 30 is composed of a mounting part body 310, a spring 320, a screw member 330, and a spring regulating member 340. Note that the configuration and function of the bolster 31, handle 32, and ferrule 33 that constitute the chisel 30 are partially common to a general chisel. Therefore, the explanation of the configuration and function common to a general chisel is omitted.

[0066] The mounting body 310 has a substantially bottomed cylindrical portion 311 with male threads 312 formed on its outer surface, a female threaded portion 313 provided on the front side of the cylindrical portion 311 and having female threads 319 formed thereon, and a blade mounting portion 314 provided on the front side of the female threaded portion 313 and to which the grommets 830 of the blade body 800 are attached.

[0067] The female screw portion 313 is formed in a tapered shape on its outer surface, with the outer diameter decreasing towards the rear. The blade mounting portion 314 has a tapered hole 318 formed in a shape complementary to the recess 830 of the blade 800.

[0068] The screw member 330 has a flange-shaped portion 331 whose outer diameter is set to be slightly smaller than the inner diameter of the cylindrical portion 311 of the mounting body 310, and a screw portion 332 provided on the front side of the flange-shaped portion 331, whose outer diameter is set to be smaller than that of the flange-shaped portion 331.

[0069] The spring 320 has an outer diameter smaller than the inner diameter of the cylindrical portion 311, and an inner diameter larger than the outer diameter of the threaded portion 332. As a result, the rearward movement of the spring 320 is restricted by the flange portion 331 of the threaded member 330 inserted into the cylindrical portion 311.

[0070] The spring regulating member 340 is a substantially cylindrical member whose inner diameter is larger than the outer diameter of the threaded portion 332 and smaller than the outer diameter of the spring 320. A male thread 341 is formed on the outer surface of the spring regulating member 340, which engages with the female thread 319 formed on the female threaded portion 313.

[0071] By setting the shapes of the mounting body 310, spring 320, screw member 330, and spring restricting member 340 in this way, the spring 320 is positioned so as to be sandwiched between the flange portion 331 of the screw member 330 and the spring restricting member 340. The forward movement of the spring 320 is then restricted by the spring restricting member 340. In addition, the screw portion 332 of the screw member 330 is positioned inside the tapered hole 318 formed in the blade mounting portion 314.

[0072] Then, by screwing the screw member 330 into the screw hole 839 of the blade body 800 and compressing the spring 320 in the direction of the central axis C, the screw member 330 is biased backward, thereby biasing the blade body 800 toward the mounting part body 310 (blade body mounting part 300), and preventing the blade body 800 from falling off the blade body mounting part 300.

[0073] The handle 32 of the chisel 30 is formed to accommodate the cylindrical portion 311 and the female screw portion 313 of the mounting body 310. In the handle 32, the portion in which the cylindrical portion 311 is housed has a female screw formed on its inner surface that engages with the male screw 312 provided on the cylindrical portion 311. The blade mounting portion 300 is fixed to the handle 32 by engaging this female screw with the male screw 312 of the cylindrical portion 311 and screwing them together.

[0074] The bolster 31 is a substantially cylindrical member, formed so that its outer diameter decreases towards the front. On the inner surface of the bolster 31, a female thread is formed that engages with the male thread formed on the outer surface of the blade mounting portion 314 on the front side. Furthermore, the bolster 31 is formed in a tapered shape where the inner diameter expands towards the rear at a position behind the portion where the female thread is formed. This tapered inner surface of the bolster 31 restricts the outward movement (away from the central axis C) of the front end of the handle 32, thereby suppressing deformation of the front end of the handle 32 when a load is applied to the handle 32.

[0075] When cutting is performed with the blade 800 (chisel 30), a forward load is applied to the handle 32. The load applied to the handle 32 is transmitted from the tapered front end of the handle 32 to both the tapered hole 318 formed in the female screw portion 313 of the mounting body 310 and the inner surface of the tapered ferrule 31. In this way, even with a hand tool like the chisel 30, the load for cutting is transmitted by the tapered surface, so the load applied to the handle 32 can be transmitted to the blade 800 more efficiently.

[0076] Furthermore, by making the blade 800 that is attached to the impact tool and the blade 800 used for the hand tool, the chisel 30, common to the same blade, it becomes possible to attach the sharp blade 800 used for the chisel 30 to the impact tool and use it without having to prepare a separate blade 800 for attachment to the impact tool.

[0077] B. Second Embodiment: Figure 6 is an exploded perspective view showing the configuration of the blade holder 10a in the second embodiment of the present invention. The blade holder 10a of the second embodiment differs from the blade adapter 200 of the first embodiment in the configuration of the blade adapter 200a. Specifically, the blade adapter 200a of the second embodiment uses a bolt 240a and a bolt receiving portion 250a instead of the screw member 230 of the blade adapter 200 of the first embodiment. Other aspects are the same as in the first embodiment, so the explanation of the contents common to the first embodiment will be omitted.

[0078] The bolt 240a is a fully threaded bolt with the same outer diameter as the threaded portion 233 of the threaded member 230 (Figures 1 and 2) of the first embodiment. The bolt receiving portion 250a is provided with a flange-shaped portion 251a and a columnar portion 252a, similar to the threaded member 230. The columnar portion 252a has a bottomed threaded hole 257a formed from the front end face towards the rear, which engages with the bolt 240a.

[0079] Then, by screwing the bolt 240a into the screw hole 257a, the bolt 240a and the bolt receiving portion 250a are assembled, and the assembled bolt 240a and bolt receiving portion 250a function in the same way as the screw member 230 of the first embodiment. Therefore, the assembled bolt 240a and bolt receiving portion 250a can be considered a "screw member". Also, the screw hole 257a of the bolt receiving portion 250a is a part that is joined in order to form a screw member, so it can also be called a "joining screw hole".

[0080] In the second embodiment, the bolt 240a is a fully threaded bolt, but if a screw (blade mounting screw) that engages with the screw hole 839 formed in the grommet 830 of the blade body 800 (Figure 3) is formed on the front side, and a screw that engages with the screw hole 257a formed in the bolt receiving portion 250a is formed on the rear side, the screw in the middle portion can be omitted. As can be seen from this, the screw on the front side of the bolt 240a can be considered a screw (blade mounting screw) that engages with the screw hole 839 in the grommet 830. Also, the screw on the rear side of the bolt 240a joins the two members, the bolt 240a and the bolt receiving portion 250a, so it can also be called a "member joining screw".

[0081] In this way, by assembling the bolt 240a and the bolt receiving portion 250a, the same function as the screw member 230 of the first embodiment (see Figures 1 to 3) can be achieved. Therefore, even when using the blade adapter 200a of the second embodiment, the blade attached to the blade holder 10a is biased toward the adapter body 210 (blade adapter 200a), thus preventing the blade from falling off the blade adapter 200a. Furthermore, by increasing the taper angle of the recess 830 (Figure 3) and the front tapered hole 218 to the extent that it is easy to remove the blade from the blade adapter 200a, the blade 800 is prevented from falling off the blade adapter 200a, and the blade 800 can be removed from the blade adapter 200a more easily.

[0082] Furthermore, in the bolt receiving portion 250a constituting the blade adapter 200a of the second embodiment, similar to the screw member 230 of the blade adapter 200 of the second embodiment, a through hole 259a perpendicular to the central axis C is formed in the columnar portion 252a, and a central hole (not shown) along the central axis C is formed in the bolt receiving portion 250a (flange portion 251a and columnar portion 252a) so as to reach the through hole 259a from the rear end face of the flange portion 251a.

[0083] These through holes 259a and the central hole formed in the bolt receiving portion 250a connect the rear tapered hole 219 and the parallel hole 217 (see Figure 2) formed in the adapter body 210, thereby suppressing the temperature rise of the adapter body 210 and the fitting 830 (Figure 3).

[0084] Thus, in the second embodiment, the bolt 240a and the bolt receiving portion 250a provide the same functionality as the screw member 230 of the first embodiment. However, by making the bolt 240a and the bolt receiving portion 250a separate components, even if the bolt 240a breaks due to impact force applied during cutting, it can be repaired by replacing the bolt 240a. In this respect, the second embodiment is preferable to the first embodiment. On the other hand, the first embodiment is preferable to the second embodiment in that the configuration of the blade adapter 200 is simpler.

[0085] C. Third Embodiment: C1. Configuration of Blade Mounting Device: Figure 7 is an exploded perspective view showing the configuration of the blade mounting device 10b in the third embodiment of the present invention. The blade mounting device 10b of the third embodiment differs from the adapter body 210 of the second embodiment in the configuration of the adapter body 210b of the blade adapter 200b. Other aspects are the same as in the second embodiment. Therefore, explanations of content common to the second embodiment will be omitted as appropriate. In particular, for components whose configuration differs depending on the embodiment, the alphabet added after the numbers in the reference numerals has been changed, but unless otherwise specified, parts with common numbers have common configurations and functions.

[0086] The blade adapter 200b has rotation-inhibiting grooves 215b formed on the front end face of the adapter body 210b to suppress the rotation of the blade. In the second embodiment, six rotation-inhibiting grooves 215b are formed at equal angles around the central axis C. The number of rotation-inhibiting grooves can be changed as appropriate, as long as it is one or more.

[0087] As will be described in more detail later, the rotation of the blade adapter 200b and the blade is suppressed when the rotation suppression member attached to the blade comes into contact with the inner surface of the rotation suppression groove 215b. The shape of the rotation suppression groove can be appropriately changed according to the shape of the rotation suppression member attached to the blade.

[0088] C2. Attaching the blade to the blade mounter: Figure 8 is a cross-sectional view showing the blade 800b having a rotation suppression member attached to the blade mounter 10b. The blade 800b is the same as the blade 800 of the first embodiment in the front part of the tip and neck. Therefore, in Figure 8, only the vicinity of the rear end of the neck 820b and the tang 830b of the blade 800b are shown. Also, since the tool mounting part 100 is the same as in the first embodiment, only a part of its front side is shown.

[0089] As shown in Figure 8, a screw hole 839b is formed in the joint 830b, similar to the blade body 800 of the first embodiment, extending forward from the rear end face. In addition to this screw hole 839b, a screw hole 838b is formed in the joint 830b near the front end, extending outward from a direction slightly inclined backward from a direction perpendicular to the central axis C. A parallel hole 837b is further formed on the tip side (central axis C side) of this screw hole 838b, extending from the screw hole 838b.

[0090] A spring 832b is inserted into the parallel hole 837b and the screw hole 838b formed in the recess 830b. Then, a bolt 831b that engages with the screw hole 838b, which acts as a rotation suppression member, is inserted from the outside and the bolt 831b is screwed in, causing the bolt 831b to move toward the parallel hole 837b.

[0091] When the bolt 831b moves toward the parallel hole 837b and comes into contact with the spring 832b, further twisting of the bolt 831b compresses the spring 832b. The repulsive force of this compressed spring 832b biases the bolt 831b outward, preventing it from falling out of the socket 830b. To avoid interference with the bolt 831b as it is inserted and moved in this manner, a notch 829b is formed at the rear end of the neck 820b of the blade body 800.

[0092] When the blade body 800b, configured with the grommet 830b and neck 820b in this manner, is attached to the blade body adapter 200b, the bolt 831b attached to the grommet 830b protrudes rearward from the front end face of the adapter body 210b (blade body adapter 200b). Therefore, the bolt 831b (rotation suppression member) is housed inside one of the rotation suppression grooves 215b formed in the adapter body 210b. When the blade body 800b rotates in this state, the bolt 831b attached to the grommet 830b comes into contact with the inner surface of the rotation suppression groove 215b formed in the adapter body 210b, thereby suppressing further rotation.

[0093] According to the third embodiment, the rotation of the blade body 800b can be suppressed by using a blade body 800b to which a rotation suppression member (bolt 831b) is attached. In this respect, the third embodiment is preferable to the first and second embodiments. On the other hand, the first and second embodiments are preferable to the third embodiment in that the configuration of the adapter body 210 constituting the blade body adapters 200, 200a is simpler.

[0094] In the third embodiment, a bolt 831b attached to the screw hole 838b of the recess 830b is used as the rotation suppression member, but the method of attaching the rotation suppression member to the blade can be changed in various ways. For example, a rod-shaped rotation suppression member may be simply inserted into a hole formed in the recess. However, in this case, there is a possibility that the rotation suppression member may fall off during use, so it is preferable to attach the bolt 831b to the screw hole 838b so that it is biased outward, as in this embodiment.

[0095] Furthermore, a protrusion can be provided on the blade's hilt or neck that extends further back than the neck, and this protrusion can serve as a rotation-restricting member. However, as in the third embodiment, by making the rotation-restricting member (bolt 831b) removable, the blade 800b can be used with the blade adapters 200 and 200a of the first and second embodiments by removing the bolt 831b and spring 832b.

[0096] C3. Configuration of the Chisel as a Manual Tool: Figure 9 is an explanatory diagram showing the configuration of a chisel 30c (hereinafter also referred to as "the chisel 30c of the third embodiment," and other components are referred to similarly) that uses the same blade body 800c as in the third embodiment. The chisel 30c differs from the chisel 30 (the chisel 30 of the first embodiment) that uses the blade body 800 of the first embodiment in that it uses the blade body 800c, the shape of the ferrule 31c has been changed, and the configuration of the blade mounting part 300c has been changed. Of the chisel 30c, the handle 32 and the ferrule 33 are the same as those of the chisel 30 of the first embodiment, and the manner in which the ferrule 31c and the blade mounting part 300c are attached to the handle 32 is the same as that of the chisel 30 of the first embodiment, so their explanation is omitted here.

[0097] The diameter of the screw hole 839c formed from the rear end face of the grommets 830c toward the front of the blade body 800c is set to be larger than that of the blade body 800b attached to the blade body adapter 200b. In other respects, it is the same as the blade body 800b attached to the blade body adapter 200b.

[0098] The jaw 31c differs from the jaw 31 of the first embodiment in that, similar to the adapter body 210b of the blade adapter 200b (Figure 7), a rotation-restricting groove 39c for accommodating a bolt 831c, which serves as a rotation-restricting member for the blade 800c, is formed on its front end face. In other respects, it is the same as the jaw 31 of the first embodiment. The jaw 31c has a single rotation-restricting groove 39c because the handle 32 constituting the chisel 30c is rotationally symmetrical about the central axis C, and the direction of rotation of the blade 800c about the central axis C can be arbitrarily changed.

[0099] In the blade mounting section 300c, similar to the blade adapter 200b, a bolt 350c and a bolt receiving section 360c with a screw hole 369c are used instead of the screw member 330. The bolt 350c is a double-threaded bolt with screw portions 352c and 353c provided on the front and rear sides of the shaft portion 351c, respectively.

[0100] The front threaded portion 352c has an outer diameter larger than that of the shaft portion 351c and is formed to engage with a threaded hole 839c formed in the groove 830c of the blade body 800c. On the other hand, the rear threaded portion 353c has an outer diameter smaller than that of the shaft portion 351c and is formed to engage with a threaded hole 369c formed in the bolt receiving portion 360c.

[0101] The mounting body 310c has a substantially bottomless cylindrical portion 311c with male threads 312c formed on its outer surface, a constricted portion 316c provided on the front side of the cylindrical portion 311c and having a protruding portion 315c that projects inward, and a blade mounting portion 314c provided on the front side of the constricted portion 316c to which the grommets 830c of the blade body 800c are attached. Similar to the jaw 31c, the blade mounting portion 314c has a rotation suppression groove 317c formed on its front end surface for accommodating a bolt 831c that serves as a rotation suppression member for the blade body 800c.

[0102] In the mounting body 310c of the third embodiment, the protruding portion 315c provided on the constricted portion 316c suppresses the forward movement of the spring 320, similar to the spring restricting member 340 in the blade mounting portion 300 of the first embodiment. Furthermore, the inner diameter of the protruding portion 315c (constricted portion 316c) is set to be smaller than the outer diameter of the threaded portion 352c on the front side of the bolt 350c, and larger than the outer diameter of the shaft portion 351c. This allows the bolt 350c to be secured inside the mounting body 310c when it is inserted into the mounting body 310c from the front.

[0103] Then, the bolt 350c is inserted into the mounting body 310c from the front, and the spring 320 and bolt receiving portion 360c are inserted into the mounting body 310c from the rear. By screwing the bolt receiving portion 360c onto the rear threaded portion 353c of the bolt 350c, the spring 320 is positioned so that it is sandwiched between the protruding portion 315c of the mounting body 310c and the bolt receiving portion 360c.

[0104] Then, the front threaded portion 352c of the bolt 350c is screwed into the threaded hole 839b of the blade body 800c, and the bolt receiving portion 360c is screwed into the front threaded portion 352c, and the spring 320 is compressed in the axial direction, thereby biasing the blade body 800c toward the mounting portion body 310c (blade body mounting portion 300c), which prevents the blade body 800c from falling off the blade body mounting portion 300c.

[0105] Furthermore, the diameter of the screw hole 839c formed in the mortise 830c of the blade 800c used in the chisel 30c is set to be larger than that of the blade 800b attached to the blade adapter 200b. However, by changing the bolt of the blade adapter to one that engages with the screw hole 839c, and appropriately modifying the configuration of the blade adapter accordingly, the blade 800c used in the hand tool chisel 30c and the blade attached to the impact tool can be made common. Therefore, it becomes possible to attach the sharp blade 800c used in the chisel 30c to the impact tool and use it without having to prepare a separate blade for the impact tool.

[0106] D. Fourth Embodiment: Figure 10 is an exploded perspective view showing the configuration of the blade holder 10d in the fourth embodiment of the present invention. For convenience of illustration, in Figure 10, the parts of the blade holder 10d are depicted as rotated around the central axis C. Although the configuration of both the tool mounting section 100d and the blade adapter 200d of the fourth embodiment of the blade holder 10d differs from that of the above embodiments, there are many parts in common with the blade holders 10, 10a, and 10b of the above embodiments. Therefore, the explanation of the parts in common with the above embodiments will be omitted.

[0107] The tool mounting portion 100d of the fourth embodiment has a base end portion 110d, a flange-shaped portion 120d, a shaft portion 130d, and a gripping portion 140d. The configuration of the base end portion 110d, the flange-shaped portion 120d, and the shaft portion 130d is the same as that of the tool mounting portion 100 in the first to third embodiments, so their description is omitted here.

[0108] The gripping portion 140d is provided on the front end side of the tapered portion 132d of the shaft portion 130d, and its outer shape is a tapered shape that extends from the tapered portion 132d. A gripping groove 149d is formed in the gripping portion 140d along the central axis C. Because the gripping groove 149 is formed, the central hole 138d is open on the front side, so it can be said that the central hole 138d is formed so that the through hole 139d is reached along the central axis C from the front end face of the tool mounting portion 100d, that is, from the rear end face of the gripping groove 149d.

[0109] The blade adapter 200d, like the blade adapter 200 of the first embodiment, has an adapter body 210b, a spring 220d, and a screw member 230d. In the blade adapter 200d of the fourth embodiment, the same adapter body 210b as in the third embodiment is used as the adapter body, but the same adapter body 210 as in the first embodiment can also be used.

[0110] The screw member 230d has a substantially disc-shaped flange portion 231d provided on the rear side and a screw portion 233d provided on the front side. The outer diameter of the flange portion 231d is set to be slightly smaller than the inner diameter of the parallel hole 217b (see Figure 8) formed in the adapter body 210b.

[0111] Furthermore, the flange portion 231d has two engagement surfaces 237d that are parallel to the central axis C and face each other. The distance between the two engagement surfaces 237d is set to be greater than the outer diameter of the threaded portion 233d. The width of the gripping groove 149d is set to be slightly wider than the distance between the engagement surfaces 237d so that at least a part of the flange portion 231d is accommodated in the gripping groove 149d of the tool mounting portion 100d and the engagement surfaces 237d and the gripping groove 149d can engage.

[0112] The threaded portion 233d is a screw that engages with the screw hole 839b formed in the socket 830b (Figure 8). The length of the threaded portion 233d is adjusted so that when the tool mounting portion 100d and the adapter body 210b are assembled and the threaded portion 233d is screwed into the screw hole 839b of the socket 830b, the engaging surface 237d of the flange portion 231d engages with the gripping groove 149d of the tool mounting portion 100d. The length of the spring 220 is also adjusted so that when the threaded portion 233d is screwed into the screw hole 839b of the socket 830b, the spring 220 is compressed by being sandwiched between the flange portion 231d of the screw member 230d and the step at the front end of the parallel hole 217b of the adapter body 210b.

[0113] In the blade mounter 10d of the fourth embodiment configured in this way, the engagement surface 237d of the flange portion 231d engages with the gripping groove 149d of the tool mounting portion 100d, thereby restricting the rotation of the screw member 230d relative to the tool mounting portion 100d. Therefore, by rotating the blade 800b relative to the tool mounting portion 100d (blade mounter 10d, impact tool 900 (Figure 4)), the screw portion 233d can be screwed into the screw hole 839b of the 830b, and the spring 220d can be compressed.

[0114] In the fourth embodiment, as in the first to third embodiments, compressing the spring 220d biases the blade 800b toward the adapter body 210d (blade adapter 200d), thereby preventing the blade 800b from falling off the blade adapter 200d.

[0115] In the fourth embodiment, unlike the first embodiment (Figure 2), the screw member 230d does not have a through hole or a central hole to form a flow path connecting the through hole 216b formed in the adapter body 210b and the front end of the tapered hole 219b (Figure 8). However, the gap between the gripping groove 149d and the flange portion 231d or the screw portion 233d, or the gap between the flange portion 231d and the parallel hole 217b or the tapered hole 219b, allows the through hole 216b formed in the adapter body 210b to communicate with the front end of the tapered hole 219b.

[0116] Therefore, in the fourth embodiment as well, the adapter body 210b and the intake 830b are cooled by compressed air supplied through the central hole 138d formed in the tool mounting portion 100d, thereby suppressing the temperature rise of the adapter body 210b and the intake 830b. However, the first to third embodiments are preferable to the fourth embodiment in that the through holes 239, 259a and the central holes 238, 258a formed in the screw member 230 and the bolt receiving portion 250a form a flow path for compressed air, and the adapter body 210, 210a, 210b and the intake 830, 830b are cooled more effectively.

[0117] On the other hand, the fourth embodiment is preferable to the first embodiment in that, since the through hole and columnar portion are omitted in the screw member 230d, stress concentration between the through hole and columnar portion and the screw portion can be suppressed, thus preventing damage to the screw member. Furthermore, the fourth embodiment is preferable to the first to third embodiments in that the configuration of the blade adapter 200d is simpler.

[0118] In the description of the fourth embodiment, for the convenience of comparison with the first to third embodiments, the gripping portion 140d and the tapered portion 132d were described separately. However, as described above, the gripping portion 140d has a tapered shape that is an extension of the tapered portion 132d. Therefore, the gripping portion 140d and the tapered portion 132d together can be called the tapered portion. In this case, the gripping groove 149d can be said to be formed at the front end of the tapered portion.

[0119] E. Modifications: The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from the spirit of the invention. For example, the following modifications are possible.

[0120] E1. Modification 1: In the above embodiments, the blade mounters 10, 10a, 10b, and 10d of the present invention are attached to a pneumatically driven impact tool 900 as shown in Figure 4. However, the blade mounters of the present invention may be attached to pneumatically driven impact tools with different configurations or to electrically driven impact tools. In these cases as well, as long as the tool mounting portion has a through hole perpendicular to the central axis and a central hole that reaches the through hole from the front end face of the tool mounting portion along the central axis, the shape of the tool mounting portion can be changed in various ways depending on the configuration of the impact tool.

[0121] In particular, in electrically driven impact tools and the like, if compressed air is not supplied, the system is configured to supply air directly to a through-hole formed in the tool mounting portion. Therefore, the through-hole does not necessarily need to be located at the rear end of the shaft.

[0122] E2. Modification 2: In each of the above embodiments, the tool mounting portion 100 and the adapter bodies 200, 200a, 200b, and 200d are fixed by interlocking complementary tapered surfaces. However, the tool mounting portion and the adapter body may be fixed using screws or the like. However, it is preferable to fix the tool mounting portion and the adapter body by interlocking complementary tapered surfaces, as this makes it possible to suppress damage to the blade holder due to the impact force applied from the impact tool.

[0123] E3. Modification 3: In the blade adapters 200, 200a, 200b, 200d of each of the above embodiments, and in the blade mounting parts 300, 300c of the chisels 30, 30c of the first and third embodiments, the configuration of each part has been changed. However, as long as no mechanical discrepancies occur, it is possible to apply any change in the configuration of the blade adapters 200, 200a, 200b, 200d, and the blade mounting parts 300, 300c to the other blade adapters or blade mounting parts.

[0124] For example, the adapter body 210 used in the blade adapter 200 of the first embodiment can be changed to one having a rotation-suppressing groove, as in the blade adapter 200b of the third embodiment.

[0125] Furthermore, in cases where the screw member is composed of a bolt and a bolt receiving portion, as in the blade adapters 200a and 200b of the second and third embodiments, the screw on the front side of the bolt (blade mounting screw) can be changed to one whose outer diameter is larger than the inner diameter of the spring or the inner diameter at the rear end of the front tapered hole.

[0126] 10, 10a, 10b, 10d...Blade mounter 30, 30c...Chisel 31, 31c...Follower 32...Handle 33...Fastener 33...Screw part 39c...Rotation suppression groove 100, 100d...Tool mounting part 110, 110d...Base end 111, 111d...Columnar part 112, 112d...Tapered part 120, 120d...Flange part 130, 130d...Shaft part 131, 131d...Main shaft part 132, 132d...Tapered part 135, 135d...Flat part 138, 138d...Center hole 139, 139d...Through hole 140d...Gripping part 149d...Gripping groove 200, 200a, 200b, 200d...Blade adapter 210, 210b...Adapter body 215b...Rotation suppression groove 216...Through hole 217...Parallel hole 218...Front tapered hole 219...Rear tapered hole 220, 220d...Spring 230, 230d...Screw member 231, 231d...Flange part 232...Columnar part 237d...Engaging surface 233, 233d...Screw part 238...Center hole 239...Through hole 240a...Bolt 250a...Bolt receiving part 251a...Flange part 252a...Columnar part 257a...Screw hole 259a...Through hole 300, 300c...Blade mounting part 310, 310c...Mounting part body 311, 311c...Cylindrical part 312, 312c...Male screw 313...Female thread section 314, 314c...Blade mounting section 315c...Protruding section 316c...Narrowed section 317c...Rotation suppression groove 318, 318c...Tapered hole 319...Female thread 320...Spring 330...Screw member 331...Flange section 332...Screw section 340...Spring regulating member 341...Male thread 350c...Bolt 351c...Shaft section 352c...Screw section 353c...Screw section 360c...Bolt receiving section 369c...Screw hole 800, 800b, 800c...Blade body 810...Brush tip 820, 820b, 830c...Neck 829b, 829c...Notch 830, 830b, 830c...Indentation 831b, 831c...Bolt 832b, 832c... Spring 837b, 837c... Parallel hole 838b, 838c... Screw hole 839, 839b... Screw hole 900... Impact tool 910... Piston 920... Cylinder 930... Cap 939... Through hole AF... Front end space C... Central axis

Claims

1. A blade adapter for attaching the blade of a chisel, which cuts a workpiece by pushing the cutting edge forward, to an impact tool via a tool mounting portion, comprising: a substantially cylindrical adapter body having a front tapered hole complementary to the inclined surface formed in the grommets of the blade and a rear tapered hole complementary to the tapered portion provided at the front end of the tool mounting portion; a spring housed inside the adapter body and restricted from moving forward relative to the adapter body; and a screw member housed inside the adapter body, having a blade mounting screw formed on the rear end face of the grommets that engages with a blade-side screw hole formed therein, and configured to be biased rearward relative to the adapter body by the spring, wherein an adapter through hole formed in the adapter body at a position between the front tapered hole and the rear tapered hole so as to be perpendicular to the central axis of the adapter body is configured to communicate with the front end of the rear tapered hole. The tool mounting portion has a through hole perpendicular to the central axis of the tool mounting portion, and a central hole extending from the front end face of the tool mounting portion along the central axis to the through hole of the tool mounting portion, in the blade adapter.

2. A blade adapter according to claim 1, wherein the screw member comprises: a substantially disc-shaped flange portion whose outer diameter is set to be larger than the outer diameter of the spring; a substantially cylindrical columnar portion provided on the front side of the flange portion and whose outer diameter is set to be smaller than the inner diameter of the spring; and a screw portion provided on the front side of the columnar portion and on which the blade mounting screw is formed, the outer diameter of which is set to be smaller than the inner diameter of the spring, wherein the columnar portion has a screw member through hole formed perpendicular to the central axis of the columnar portion, and the columnar portion and the flange portion have a screw member central hole formed along the central axis, reaching from the rear end face of the flange portion to the screw member through hole.

3. A blade adapter according to claim 1, wherein the screw member comprises: a blade mounting screw; a bolt on which a member joining screw for forming the screw member is formed; a bolt receiving portion having a substantially cylindrical columnar portion having a joining screw hole that engages with the member joining screw and whose outer diameter is set to be smaller than the inner diameter of the spring; and a substantially disc-shaped flange portion provided on the rear side of the columnar portion and whose outer diameter is set to be larger than the outer diameter of the spring, wherein the columnar portion has a screw member through hole formed perpendicular to the central axis of the columnar portion at a position rearward from the joining screw hole, and the columnar portion and the flange portion have a screw member central hole formed along the central axis, reaching from the rear end face of the flange portion to the screw member through hole.

4. A blade adapter according to claim 1, wherein the screw member has a screw portion on which a blade mounting screw is formed, the outer diameter of which is set to be smaller than the inner diameter of the spring; and a flange-shaped portion provided on the rear side of the screw portion, which is substantially disc-shaped, the outer diameter of which is set to be larger than the outer diameter of the spring, and which has two engaging surfaces formed parallel to the central axis and facing each other at a distance wider than the outer diameter of the screw portion, and a gripping groove wider than the distance between the two engaging surfaces is formed at the front end of the tapered portion.

5. The blade adapter according to any one of claims 1 to 4, wherein a rotation suppression groove is formed on the front end face of the adapter body, and a rotation suppression portion provided on the blade body that protrudes rearward from the neck of the blade body contacts it.

6. A chisel blade that can be attached to a blade adapter according to any one of claims 1 to 4, wherein the mortise is formed in a tapered shape complementary to the front tapered hole formed in the adapter body, and a screw hole is formed on the rear end face of the mortise that engages with the blade mounting screw formed in the screw member.

7. A chisel blade to be attached to the blade adapter according to claim 5, wherein the mortise is formed in a tapered shape complementary to the front tapered hole formed in the adapter body, a screw hole is formed on the rear end face of the mortise that engages with the blade mounting screw formed in the screw member, and the blade is provided with a rotation suppression portion that protrudes rearward from the neck of the blade and is configured to contact the inside of a rotation suppression groove formed in the adapter body.

Images