Grinder provided with push stopper module

Abstract

The present invention relates to a grinder provided with a push stopper module, wherein the push stopper module is formed as an integrated assembly and structurally improved so as to be disassemblable and reassemblable by a screw-fastening method, thus having enhanced assemblability and making it possible to partially replace the push stopper module in case of failure. Also, a protective cover protects a push button to provide safety by preventing malfunctions caused by accidental pressing of the push button due to improper operation while preventing damage from external forces. In particular, during the fastening of a grinding wheel, impact is doubly absorbed by a disc spring and an elastic O-ring as a holder upper is compressed and moved into an annular compartment, and a smooth unlocking / locking operation of a wheel holder flange can be achieved. To this end, the grinder includes a grinder body (10), a spindle (20), a stop groove (30), a push stopper module (40), and a grinding stone holder module (50) as the main components.

Description

A grinder equipped with a push stopper module

[0001] The present invention relates to a grinder equipped with a push stopper module, and more specifically, to a grinder equipped with a push stopper module in which the push stopper module is formed as an integrated assembly and structurally improved to allow for disassembly and assembly via a screw connection method, thereby improving assemblability and enabling partial replacement of the push stopper module in the event of failure. Furthermore, the push button is protected by a protective cover to prevent damage from external forces and provides safety by preventing malfunctions where the push button is pressed due to improper operation. In particular, when a grinding wheel is fastened, the holder upper moves inwardly into the annular chamber in a compressed manner, and shock is absorbed twice by a disc spring and an elastic O-ring, while also providing smooth locking / unlocking operation of the wheel holder flange.

[0002]

[0003] Typically, a hand grinder is a tool operated by high-pressure air or a motor, and it performs machining operations by attaching grinding wheels of various sizes to the tip of a rotating body and utilizing high-speed rotational force and frictional force. Here, machining operations include not only surface finishing of welded parts in the shipbuilding and heavy industry sectors, finishing of metal castings, and surface machining such as aluminum die casting, but also finishing or polishing of metals, wood, and ceramics, and mold making for metal forgings.

[0004] In addition, a hand grinder using high-pressure air is configured such that a cylinder is provided inside the main body, a rotor is provided inside the cylinder, a plurality of blades are installed at equal intervals on the outer surface of the rotor, an air supply means is connected to an air inlet bushing at the rear of the main body, and high-pressure air supplied from the air supply means is supplied into the interior of the cylinder through the air supply port of the rear plate, the rotor is rotated by the pressure of the supplied air, and the rotational force of the rotor is configured to rotate a rotating shaft provided at the front end of the main body by changing the direction of rotation by a bevel gear which is a power transmission means.

[0005] Looking at such conventional hand grinder technology, registered patent No. 10-1483963 presented a technology in which a rotating means is fitted so as to be supported by a support ledge formed on the rotating shaft of a hand disc grinder, the rotating shaft is made to protrude from the rotating means, the rotating means is coupled so that a support body is fitted into the rotating body and does not detach, while a thrust bearing is installed between the support body and the rotating body, the support body constituting the rotating means is supported by the support ledge of the rotating shaft, and a grinding disc is screw-coupled to the rotating shaft and pressed against the rotating body at a position symmetrical to the support body, and the grinding disc fitted into the rotating shaft is coupled by compressing the rotating means as a screw portion of a coupling ring formed in the center is screw-coupled to the rotating shaft. However, due to the complexity of the fastening device and the difficulty of the fastening process, the operator cannot perform replacement work quickly and easily, and there was a problem that it was difficult to apply to existing air grinders because a separate fastening device is installed on the rotating shaft of the air grinder.

[0006] In addition, in another prior art, Registered Patent No. 10-2446463, regarding an air grinder operated by connecting to air to grind the surface of a processed metal by engaging a grinder wheel with a single touch, the air grinder comprises: a rotational transmission shaft engaged with and rotating the rotational shaft of the air grinder; a power transmission gear formed to rotate and integrally connected to the inner side of the rotational transmission shaft; and a screw-shaped connecting screw integrally connected to the upper end of the power transmission gear; a one-touch coupler connected to the connecting screw of the power transmission unit to engage the grinder wheel; and a stopper detachable seating part having an elongated hole cut portion formed on one side of the inner side of the rotational transmission shaft of the power transmission unit, with the cut portion having an elongated hole shape. Although a technology has been previously presented comprising a one-touch stopper that is seated in a through hole penetrating one side of the air grinder and is detachably attached to the elongated cut portion of the stopper attachment / detachment part to block the rotation of the power transmission part, wherein the one-touch stopper is formed by a cylindrical stopper body screw-fastened to the through hole, having an insertion hole penetrating the inner side and a stepped seating portion formed on the upper side, a stopper rod that blocks the rotational force of the power transmission part by reciprocating back and forth with a ring-shaped protruding locking projection formed to fix a spring seated on the inner side of the stopper body, a circular seating washer that fixes the stopper rod to the stopper body, and a button connected to the seating washer and gripped by hand, and a balance washer formed in a disc shape of a predetermined thickness on the upper side of the elastic washer of the one-touch coupler to allow rotation while forming the flatness of the grinder wheel attached to the upper side, the coupling structure between the parts is complex There were difficulties in assembly work by unskilled workers, and problems such as frequent breakdowns occurred during use.

[0007]

[0008] Accordingly, the present invention is conceived to solve the aforementioned problems, and aims to provide a grinder equipped with a push stopper module in which the push stopper module is formed as an integrated assembly and structurally improved to allow for disassembly and assembly via a screw connection method, thereby enhancing assembly ease and enabling partial replacement of the push stopper module in the event of failure. Furthermore, the push button is protected by a protective cover to prevent damage from external forces and provides safety by preventing malfunctions caused by improper operation of the push button. In particular, when a grinding wheel is attached, the holder upper moves inwardly into the annular chamber in a compressed manner, and shock is absorbed twice by a disc spring and an elastic O-ring, while also providing smooth locking and unlocking operation of the wheel holder flange.

[0009]

[0010] To achieve this purpose, the present invention is characterized by comprising: a grinder body (10) having a spindle casing (11) formed therein and a plurality of bearings (12) installed inside the spindle casing (11); a spindle (20) installed in the spindle casing (11) and rotated by a driving unit, having a male screw shaft (21) formed at one end; a stop groove (30) provided to be spaced apart in the circumferential direction on the outer surface of the spindle (20); a push stopper module (40) installed in the spindle casing (11) and provided to restrain the spindle (20) by engaging with the stop groove (30) by a push operation; and a grinding stone holder module (50) installed on the male screw shaft (21) of the spindle (20) and provided to restrain a grinding stone (G).

[0011] At this time, the push stopper module (40) comprises: a female screw hole (41) formed on a spindle casing (11) corresponding to a circumferential area of ​​a spindle (20) where a stop groove (30) is formed; a bushing (42) that is screw-fastened to the female screw hole (41) and has first and second rod holes (42a) (42b) having different diameters formed concentrically inside; a button stopper (43) in which first and second rod rods (43a) (43b) having different diameters are formed concentrically to be inserted into the first and second rod holes (42a) (42b), a stop pin (43c) is provided at one end of the first rod rod (43a) corresponding to the stop groove (30), and a push button (43d) is formed at one end of the second rod rod (43b); and a device inserted into the first rod rod (43a). It is characterized by including a spring (44) disposed within the second rod hole (42b) and configured to be compressed when the button stopper (43) is pressed toward the stop groove (30), an outer ring snap groove (45) formed at the boundary between the first rod (43a) and the stop pin (43c), an outer ring snap ring (46) installed in the outer ring snap groove (45) exposed outside the first rod hole (42a) to restrict the movement of the button stopper (43), and a push-O ring (47) installed on one or more of the first and second rods (43a) (43b) to maintain airtightness.

[0012] Additionally, a protective cover (60) is formed protruding from the outer surface of the spindle casing (11) to surround the outer surface of the push button (43d), and a stop flange (61) is formed at the end of the bushing (42) exposed toward the protective cover (60). The stop flange (61) contacts the outer surface of the spindle casing (11) to limit the screw fastening depth of the bushing (42). The stop flange (61) is formed with a size expanded relative to the outer diameter of the push button (43d) and has a keyway (62) formed on its outer surface. The bushing (42) can be loosened or tightened by inserting a tool into the protective cover (60) and fastening it in the keyway (62).

[0013] Additionally, the grinding stone holder module (50) comprises: a holder lower (51) having an inner tube body (51a) formed in the center to be screw-fastened to a male screw shaft (21), and an outer tube body (51b) formed concentrically to the inner tube body (51a) to form an annular compartment (51c); a holder upper (52) formed annularly to be inserted into the annular compartment (51c), with an annular jaw (52a) on one side protruding outside the annular compartment (51c) and supported in contact with the grinding stone (G); an inner ring snap ring (53) that is fitted into an inner ring snap groove (53a) formed on the inner circumference of the outer tube body (51b) to restrain the holder upper (52); and a shaft hole (54a) formed in the center to allow the male screw shaft (21) to be inserted while being received in the annular compartment (51c). The device is characterized by including a disc spring (54) in which the inner diameter area corresponding to the shaft hole (54a) contacts the holder lower (51) and the outer diameter area contacts the holder upper (52), thereby pressing the holder upper (52) toward the grinding wheel (G); an elastic O-ring (55) disposed on the inner surface of the annular compartment (51c) to press the disc spring (54) toward the holder upper (52); and a wheel holder flange (56) screw-fastened to the male screw shaft (21) to restrain the grinding wheel (G).

[0014] Additionally, the holder upper (52) is provided so that a pressure is applied toward the grinding wheel (G) by a hydraulic / pneumatic shock absorber module (57), and the hydraulic / pneumatic shock absorber module (57) includes an inner ring O-ring (57a) installed on the inner surface of the holder upper (52) to maintain airtightness between the inner tube body (51a) and the outer surface of the holder upper (52), an outer ring O-ring (57b) installed on the inner surface of the outer tube body (51b) to maintain airtightness between the holder upper (52) and the outer surface of the holder upper (52), an air layer (57c) formed inside the annular compartment (51c) sealed by the holder upper (52), and an oil layer (57d) introduced into the annular compartment (51c) sealed by the holder upper (52) to regulate the volume of the air layer (57c), and when the holder upper (52) moves into the annular compartment (51c), the air layer (57c) is compressed It is characterized by absorbing the impact applied to the holder upper (52) side and being configured so that the holder upper (52) is pressed toward the grinding wheel (G) side by the expansion force of the air layer (57c), and being configured so that the pressure of the holder upper (52) can be adjusted by the volume of the oil layer (57d).

[0015] In addition, the holder upper (52) is formed in a type in which a flat pressure portion (52b) or an annular protrusion portion (52c) is formed on one surface corresponding to the grinding wheel (G), and is characterized by being provided so that the holder upper (52) can be replaced and applied considering the type of the grinding wheel (G).

[0016]

[0017] According to the above configuration and operation, the present invention improves the structure so that the push stopper module is formed as an integrated assembly and can be disassembled and assembled using a screw connection method, thereby enhancing assembly ease and allowing the push stopper module to be partially replaced in the event of failure. Furthermore, the push button is protected by a protective cover to prevent damage from external forces and provides safety by preventing malfunctions caused by improper operation of the push button. In particular, when a grinding wheel is attached, the holder upper moves inwardly in the annular chamber, and shock is absorbed twice by the disc spring and elastic O-ring, while also providing the effect of smooth locking / unlocking operation of the wheel holder flange.

[0018]

[0019] FIG. 1 is a configuration diagram showing the internal structure of a grinder equipped with a push stopper module according to an embodiment of the present invention.

[0020] FIG. 2 is a disassembled configuration diagram showing a push stopper module of a grinder equipped with a push stopper module according to an embodiment of the present invention.

[0021] FIG. 3 is a configuration diagram showing the operating state of a push stopper module of a grinder equipped with a push stopper module according to an embodiment of the present invention.

[0022] FIG. 4 is a configuration diagram showing a grinding stone holder module of a grinder equipped with a push stopper module according to an embodiment of the present invention.

[0023] FIG. 5 is a configuration diagram showing a hydraulic shock absorber module of a grinder equipped with a push stopper module according to an embodiment of the present invention.

[0024] FIG. 6 is a configuration diagram showing a modified example of a holder upper of a grinder equipped with a push stopper module according to an embodiment of the present invention.

[0025]

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Furthermore, in describing the present invention, detailed descriptions of related known functions are omitted if they are deemed obvious to those skilled in the art and could unnecessarily obscure the essence of the invention.

[0027] FIG. 1 is a configuration diagram showing the internal structure of a grinder equipped with a push stopper module according to an embodiment of the present invention; FIG. 2 is a configuration diagram showing the push stopper module of a grinder equipped with a push stopper module according to an embodiment of the present invention in an exploded view; FIG. 3 is a configuration diagram showing the operating state of the push stopper module of a grinder equipped with a push stopper module according to an embodiment of the present invention; FIG. 4 is a configuration diagram showing the grinding stone holder module of a grinder equipped with a push stopper module according to an embodiment of the present invention; FIG. 5 is a configuration diagram showing the hydraulic / pneumatic shock absorber module of a grinder equipped with a push stopper module according to an embodiment of the present invention; and FIG. 6 is a configuration diagram showing a modified example of the holder upper of a grinder equipped with a push stopper module according to an embodiment of the present invention.

[0028] The present invention relates to a grinder equipped with a push stopper module, wherein the push stopper module is formed as an integrated assembly and structurally improved to be disassembled and assembled by a screw connection method, thereby improving assembly and allowing the push stopper module to be partially replaced in the event of failure. Additionally, the push button is protected by a protective cover to prevent damage from external forces and provides safety by preventing malfunctions where the push button is pressed due to lack of skill in operation. In particular, when a grinding wheel is attached, the holder upper is compressed and moved into the annular chamber, and shock is absorbed twice by a disc spring and an elastic O-ring, and the grinder is configured to provide smooth locking / unlocking operation of the wheel holder flange. The main components include a grinder body (10), a spindle (20), a stop groove (30), a push stopper module (40), and a grinding wheel holder module (50).

[0029] The grinder body (10) according to the present invention has a spindle casing (11) formed therein, and a plurality of bearings (12) are installed inside the spindle casing (11).

[0030] The above grinder body (10) is equipped with a drive unit including an electric motor and an air motor inside, and the rotation axis of the drive unit extends to a spindle casing (11) and is configured to drive a spindle (20) described later by a gear assembly including a bevel gear.

[0031] At this time, the spindle casing (11) is opened in one direction, with one end exposed to the outside while receiving the spindle (20) described later, and a plurality of bearings (12) are installed on the inner surface to rotatably support the spindle (20).

[0032] In addition, the spindle (20) according to the present invention is installed in the spindle casing (11) and rotated by a driving unit, and a male screw shaft (21) is formed at one end.

[0033] The above spindle (20) is configured to rotate by the power of a driving unit to rotate a grinding wheel (G), and a male screw shaft (21) for attaching the grinding wheel (G) to one end is exposed outside the spindle casing (11).

[0034] In addition, the stop groove (30) according to the present invention is provided to be spaced apart in the circumferential direction on the outer surface of the spindle (20).

[0035] The above stop grooves (30) can be arranged at two locations at an equal angle of 180˚ on the outer surface of the spindle (20), at three locations at an equal angle of 120˚, or at four locations at an equal angle of 90˚.

[0036] And, the stop groove (30) is configured to restrain the spindle (20) by engaging with the stop pin (43c) of the push stopper module (40) described later, and is formed with a size expanded relative to the outer diameter of the stop pin (43c).

[0037] In addition, the push stopper module (40) according to the present invention is installed in the spindle casing (11) and is configured to engage with the stop groove (30) by pushing operation to restrain the spindle (20).

[0038] The above push stopper module (40) is operated by a push pressure applied by a worker's hand to simply restrain the spindle (20), and is provided so that the grinding wheel (G) can be simply replaced as the spindle (20) is restrained.

[0039] In FIG. 2, the push stopper module (40) comprises: a female screw hole (41) formed on a spindle casing (11) corresponding to a circumferential region of a spindle (20) where a stop groove (30) is formed; a bushing (42) that is screw-fastened to the female screw hole (41) and has first and second rod holes (42a) (42b) having different diameters formed concentrically inside; a button stopper (43) in which first and second rod rods (43a) (43b) having different diameters are formed concentrically to be inserted into the first and second rod holes (42a) (42b), a stop pin (43c) is provided at one end of the first rod rod (43a) corresponding to the stop groove (30), and a push button (43d) is formed at one end of the second rod rod (43b); and a button stopper (43) that is inserted into the first rod rod (43a). It includes a spring (44) positioned within the second rod hole (42b) and configured to be compressed when the button stopper (43) is pressed toward the stop groove (30); an outer ring snap groove (45) formed at the boundary between the first rod rod (43a) and the stop pin (43c); an outer ring snap ring (46) installed in the outer ring snap groove (45) exposed outside the first rod hole (42a) to restrict the movement of the button stopper (43); and a push-O ring (47) installed on one or more of the first and second rod rods (43a) (43b) to maintain airtightness.

[0040] At this time, the push-O ring (47) is provided to maintain airtightness between the first and second rod holes (42a) (42b) and the first and second rod rods (43a) (43b) to prevent external leakage of lubricating oil inside the spindle casing (11) and to block external foreign matter from entering the spindle casing (11).

[0041] In addition, since the button stopper (43) is assembled to the bushing (42) together with the spring (44) and restrained by the outer ring snap ring (46) to form an integrated assembly, assembly is improved during the manufacturing process, and there is an advantage that the push stopper module (40) can be partially replaced in the event of failure.

[0042] In operation, when the push button (43d) of the push stopper module (40) is pressed as in FIG. 3, the button stopper (43) moves linearly inward toward the spindle casing (11) and the spring (44) is compressed, and the spindle (20) is stopped with the stop pin (43c) engaged with the stop groove (30), so that the grinding stone (G) can be easily replaced by loosening or tightening the grinding stone holder module (50) described later.

[0043] In addition, a protective cover (60) is formed protruding from the outer surface of the spindle casing (11) to surround the outer surface of the push button (43d). This safely protects the protective cover (60) from external impact and prevents malfunctions in which the push button (43d) is pressed due to improper operation.

[0044] Additionally, a stop flange (61) is formed at the end of the bushing (42) exposed toward the protective cover (60), and the stop flange (61) is provided to contact the outer surface of the spindle casing (11) to limit the screw fastening depth of the bushing (42).

[0045] At this time, the stop flange (61) is formed with an expanded size relative to the outer diameter of the push button (43d), and a keyway (62) is formed on the outer surface.

[0046] Accordingly, by being configured so that a tool can be inserted into the protective cover (60) and the bushing (42) can be loosened or tightened while secured in the keyway (62), the assembly of the push stopper module (40) is improved during the manufacturing process, and there is an advantage that anyone can easily partially replace the push stopper module (40) in the event of a malfunction at the site.

[0047] In addition, the grinding stone holder module (50) according to the present invention is installed on the male screw shaft (21) of the spindle (20) to restrain the grinding stone (G).

[0048] In FIG. 4, the grinding stone holder module (50) comprises: a holder lower (51) having an inner tube body (51a) formed in the center to be screw-fastened to a male screw shaft (21), and an outer tube body (51b) formed concentrically to the inner tube body (51a) to form an annular compartment (51c); a holder upper (52) formed annularly to be inserted into the annular compartment (51c), with an annular jaw (52a) on one side protruding outside the annular compartment (51c) and supported in contact with the grinding stone (G); an inner ring snap ring (53) that is fitted into an inner ring snap groove (53a) formed on the inner circumference of the outer tube body (51b) to restrain the holder upper (52); and a shaft hole (54a) formed in the center to allow the male screw shaft (21) to be inserted while being received in the annular compartment (51c). It includes a disc spring (54) in which the inner diameter area corresponding to the shaft hole (54a) contacts the holder lower (51) and the outer diameter area contacts the holder upper (52), thereby pressing the holder upper (52) toward the grinding wheel (G); an elastic O-ring (55) disposed on the inner surface of the annular compartment (51c) to press the disc spring (54) toward the holder upper (52); and a wheel holder flange (56) screw-fastened to the male screw shaft (21) to restrain the grinding wheel (G).

[0049] At this time, when the grinding wheel (G) inserted into the male screw shaft (21) is fastened using the wheel holder flange (56), the holder upper (52) moves into the annular compartment (51c), and the shock is absorbed twice by the disc spring (54) and the elastic O-ring (55). In particular, there is an advantage that the wheel holder flange (56) is smoothly locked / unlocked by the elastic movement of the holder upper (52).

[0050] In addition, the holder upper (52) is provided so that a pressing force is applied to the grinding wheel (G) side by the hydraulic / pneumatic shock absorber module (57).

[0051] In FIG. 5, the hydraulic shock absorber module (57) includes an inner ring O-ring (57a) installed on the inner surface of the holder upper (52) to maintain airtightness between the inner tube body (51a) and the outer surface of the holder upper (52), an outer ring O-ring (57b) installed on the inner surface of the outer tube body (51b) to maintain airtightness between the outer surface of the holder upper (52), an air layer (57c) formed inside an annular compartment (51c) sealed by the holder upper (52), and an oil layer (57d) introduced into the annular compartment (51c) sealed by the holder upper (52) to control the volume of the air layer (57c).

[0052] At this time, the oil layer (57d) is provided to form a volume of 40 to 60% of the total volume of the annular compartment (51c) sealed by the holder upper (52). If the volume of the oil layer (57d) is less than 40%, the air layer (57c) expands and the cushioning elasticity decreases, and if the volume of the oil layer (57d) exceeds 60%, the air layer (57c) shrinks and the cushioning efficiency by the holder upper (52) decreases.

[0053] That is, when the holder upper (52) moves into the annular compartment (51c), the air layer (57c) is compressed to absorb the impact applied to the holder upper (52), and the holder upper (52) is pressed toward the grinding wheel (G) by the expansion force of the air layer (57c), and the pressure of the holder upper (52) can be adjusted by the volume of the oil layer (57d).

[0054] In FIG. 6, the holder upper (52) is formed in a type in which a flat pressure portion (52b) or an annular projection portion (52c) is formed on one surface corresponding to the grinding wheel (G), and is provided so that the holder upper (52) can be replaced and applied considering the type of the grinding wheel (G).

[0055] FIG. 6 (a) shows a holder upper (52) with a flat pressure portion (52b) formed thereon, and FIG. 6 (b) shows a holder upper (52) with an annular projection portion (52c) applied thereto.

[0056] In addition, the holder upper (52) is configured so that it can be easily replaced by separating the inner ring snap ring (53), so there is an advantage in that a holder upper (52) suitable for the grinding wheel (G) type can be easily replaced and applied on-site.

[0057] As described above, the detailed description of the present invention has explained the most preferred embodiment of the present invention, but various modifications are possible within the scope of the technical scope of the present invention. Accordingly, the scope of protection of the present invention should not be limited to the above embodiment, but should be recognized to include the technologies of the claims described below and equivalent technical means derived from these technologies.

[0058]

[0059] 10: Grinder body 20: Spindle

[0060] 30: Stop Home 40: Push Stopper Module

[0061] 50: Grinding stone holder module 60: Protective cover

Claims

A grinder body (10) having a spindle casing (11) formed therein and a plurality of bearings (12) installed inside the spindle casing (11); a spindle (20) installed in the spindle casing (11) and rotated by a driving unit, having a male screw shaft (21) formed at one end; a stop groove (30) provided to be spaced apart in the circumferential direction on the outer surface of the spindle (20); a push stopper module (40) installed in the spindle casing (11) and provided to restrain the spindle (20) by engaging with the stop groove (30) by a push operation; and a grinding stone holder module (50) installed on the male screw shaft (21) of the spindle (20) and provided to restrain a grinding stone (G). The above push stopper module (40) comprises: a female screw hole (41) formed on a spindle casing (11) corresponding to a circumferential area of ​​a spindle (20) where a stop groove (30) is formed; a bushing (42) that is screw-fastened to the female screw hole (41) and has first and second rod holes (42a) (42b) having different diameters formed concentrically inside; a button stopper (43) in which first and second rod rods (43a) (43b) having different diameters are formed concentrically to be inserted into the first and second rod holes (42a) (42b), a stop pin (43c) is provided at one end of the first rod rod (43a) corresponding to the stop groove (30), and a push button (43d) is formed at one end of the second rod rod (43b); and a device inserted into the first rod rod (43a). It includes a spring (44) disposed within the second rod hole (42b) and configured to be compressed when the button stopper (43) is pressed toward the stop groove (30); an outer ring snap groove (45) formed at the boundary between the first rod (43a) and the stop pin (43c); an outer ring snap ring (46) installed in the outer ring snap groove (45) exposed outside the first rod hole (42a) to restrict the movement of the button stopper (43); and a push-O ring (47) installed on one or more of the first and second rods (43a) (43b) to maintain airtightness. A protective cover (60) is formed protruding from the outer surface of the spindle casing (11) to surround the outer surface of the push button (43d), and A stop flange (61) is formed at the end of the bushing (42) exposed toward the protective cover (60), and the stop flange (61) contacts the outer surface of the spindle casing (11) to limit the screw fastening depth of the bushing (42). The above stop flange (61) is formed with an expanded size relative to the outer diameter of the push button (43d), and a keyway (62) is formed on the outer surface. A grinder equipped with a push stopper module characterized by being configured to allow loosening or tightening of a bushing (42) by inserting a tool into the protective cover (60) and securing it to the keyway (62). In Article 1, The above grinding stone holder module (50) is, A holder lower (51) having an inner tube body (51a) formed in the center to be screw-fastened to a male screw shaft (21), and an annular compartment (51c) formed by an outer tube body (51b) that is expanded concentrically with the inner tube body (51a), and A holder upper (52) formed in an annular shape to be inserted into an annular compartment (51c), and having an annular jaw (52a) on one side protruding outside the annular compartment (51c) and supported in contact with a grinding wheel (G), and An inner ring snap ring (53) that is fitted into an inner ring snap groove (53a) formed on the inner surface of an outer tube body (51b) to restrain a holder upper (52), and A disc spring (54) having a shaft hole (54a) formed in the center so that a male screw shaft (21) is inserted while being received in an annular compartment (51c), an inner diameter area corresponding to the shaft hole (54a) contacts the holder lower (51), and an outer diameter area contacts the holder upper (52), thereby pressing the holder upper (52) toward the grinding wheel (G); An elastic O-ring (55) positioned on the inner side of the annular compartment (51c) to press the disc spring (54) toward the holder upper (52), and A grinder equipped with a push stopper module characterized by including a wheel holder flange (56) that is screw-fastened to a male screw shaft (21) and restrains a grinding wheel (G). In Paragraph 4, The above holder upper (52) is provided so that a pressing force is applied toward the grinding wheel (G) by the hydraulic / pneumatic shock absorber module (57), and The above hydraulic shock absorber module (57) is, An inner ring O-ring (57a) installed on the inner surface of the holder upper (52) to maintain airtightness between the inner tube body (51a) and the outer surface, and An outer ring O-ring (57b) installed on the inner surface of the outer tube body (51b) to maintain airtightness between the outer surface of the holder upper (52), and An air layer (57c) formed inside an annular compartment (51c) sealed by a holder upper (52), and It includes an oil layer (57d) that is inserted into an annular compartment (51c) sealed by a holder upper (52) and controls the volume of an air layer (57c), and When the above-mentioned holder upper (52) moves into the annular compartment (51c), the air layer (57c) is compressed to absorb the impact applied to the holder upper (52), and the holder upper (52) is pressed toward the grinding wheel (G) by the expansion force of the air layer (57c). A grinder equipped with a push stopper module characterized by being configured to adjust the pressure of the holder upper (52) by the volume of the oil layer (57d). In Paragraph 4, A grinder equipped with a push stopper module, characterized in that the holder upper (52) is formed in a type in which a flat pressure portion (52b) or an annular protrusion portion (52c) is formed on one surface corresponding to the grinding wheel (G), and the holder upper (52) is provided so as to be replaceable in consideration of the type of the grinding wheel (G).

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