GRINDING MACHINE

Abstract

A grinding tool comprises a grinding section having a flat sheet placement surface on which a grinding sheet can be placed, and a clamping mechanism configured to hold the grinding sheet to the grinding section. The clamping mechanism includes a clamping element configured to hold the grinding sheet and to be moved in a direction parallel to the sheet placement surface between a closed position for holding the grinding sheet and an open position for allowing removal of the grinding sheet, an elastic element that applies a preload force to bias the clamping element toward the closed position in a direction parallel to the sheet placement surface, and a holding mechanism configured to hold the clamping element in the open position against the preload force.The clamping part can hold the sanding sheet when the holding mechanism is released from holding the clamping part in the open position.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a grinding device. BACKGROUND

[0002] Sanders are known which have a clamping mechanism for holding an abrasive sheet (sandpaper). JP 2010-207964 A discloses a sander comprising a torsion spring, a clamping lever, and a clamping member. The clamping lever is formed at one end of the torsion spring, and the clamping member is connected to the other end of the torsion spring. When the clamping lever is locked to a protruding locking portion by a user while the torsion spring maintains the biasing force, the clamping member holds the abrasive sheet by the biasing force. JP H2-15256 U discloses a sander in which the clamping member is moved up and down by a user's operation of the clamping lever to hold and release (release) the abrasive sheet. The clamping member holds the abrasive sheet by being biased by the torsion spring. SHORT SUMMARY

[0003] In the sander disclosed in JP 2010-207964 A, it is necessary for a user to lift the clamp lever and lock the clamp lever to the protruding locking member against the biasing force of the torsion spring to hold the sanding sheet. Therefore, the operability of the clamp lever is poor when operating the clamp lever while pressing the sanding sheet with one hand of the user. In the sander disclosed in JP H2-15256 U, the clamp member and the torsion spring are moved up and down, so the structure of the clamping mechanism is enlarged in the up-down direction.

[0004] Accordingly, it is an object of the present disclosure to provide an improvement in a clamping mechanism in a grinding device.

[0005] The above-mentioned object is achieved by a grinding device according to claim 1.

[0006] According to one non-limiting aspect of the present disclosure, a sanding device is provided that includes a sanding part and at least one clamping mechanism. The sanding part has a flat sheet placement surface (sheet support surface) on which a sanding sheet (sandpaper) can be placed. The at least one clamping mechanism is configured to hold the sanding sheet to the sanding part. The at least one clamping mechanism includes a clamping part, at least one elastic member, and a holding mechanism. The clamping part is configured to hold the sanding sheet and to be displaced in a direction parallel to the sheet placement surface between a closed position for holding the sanding sheet on a side surface of the sanding part and an open position for allowing removal of the sanding sheet.The at least one elastic element applies a biasing force to bias the clamping part toward the closed position in a direction parallel to the sheet placement surface. The holding mechanism is configured to hold the clamping part in the open position against the biasing force. In the sanding device, the clamping part is allowed to hold the sanding sheet when the holding mechanism is released from holding the clamping part in the open position.

[0007] According to this aspect, when the user of the sander places a sanding sheet on the clamping part held in the open position by the holding mechanism, and then (manually) operates the holding mechanism to release the clamping part from the open position, the clamping part is moved to the closed position while the biasing force of the elastic member is applied in addition to the user's force for operating the holding mechanism. Therefore, the sanding sheet can be held by the clamping member with a simple operation by the user. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a right side view of a grinder. Fig. 2 is a longitudinal center cross-sectional view of the grinder for illustrating the internal structure. Fig. 3 is a perspective view showing the front of the grinder. Fig. 4 is a perspective view showing the back of the sanding sheet. Fig. 5 is an exploded perspective view showing a clamping mechanism. Fig. 6 is a bottom view showing a cam lever. Fig. 7 is a side view showing the cam lever. Fig. 8 is a plan view showing the clamping mechanism in the closed state and a base. Fig. 9 is a plan view showing the clamping mechanism in the open state and the base. Fig. 10 is an explanatory view showing the relationship between a clamping part and a clamping member in the closed state. Fig. 11 is an explanatory view showing the relationship between the clamping part and the clamping member when the clamping part is rotated in the opening direction from the closed position as a starting point. Fig. 12 is an explanatory view showing the relationship between the clamping part and the clamping member in the maximum open state. Fig. 13 is an explanatory view showing the relationship between the clamping part and the clamping member in the rotation stop position. Fig. 14 shows the clamping mechanism in the closed state. Fig. 15 shows the clamping mechanism in the open state. Fig. 16 is an explanatory view showing the closed state of a clamp mechanism using a rubber member as the elastic member. Fig. 17 is an explanatory view showing the open state of the clamp mechanism using the rubber member as the elastic member. Fig. 18 is an explanatory view showing the closed state of a clamp mechanism using a tension spring as the elastic member. Fig. 19 is an explanatory view showing the open state of the clamping mechanism using the tension spring as the elastic member. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0008] In one non-limiting embodiment of the present disclosure, the sanding implement may include an elongated handle. A direction perpendicular to the blade placement surface defines an up-down direction of the sanding implement, and a direction in which the handle extends when viewed from (in) the up-down direction defines a front-back direction of the sanding implement. The at least one clamping mechanism may include a front clamping mechanism disposed forward of a center of the sanding part. The at least one clamping mechanism may include a rear clamping mechanism disposed rearward of the center of the sanding part.

[0009] According to this embodiment, the front and rear clamping mechanisms are arranged in the same direction as the extension of the handle, so that the increase in size of the grinder in the left-right direction can be suppressed (prevented).

[0010] Additionally or alternatively to the previous embodiment, each of the at least one elastic element may be an elongated spring. The spring may extend in a direction parallel to the blade placement surface.

[0011] According to this embodiment, the spring extends in a direction parallel to the sheet placing surface, so that the increase in size of the clamping mechanism in the up-down direction due to the presence of the spring can be suppressed (prevented).

[0012] In addition or alternatively to the preceding embodiments, each of the at least one elastic element may be an elongated compression spring. The elongated spring may extend in a direction parallel to the blade placement surface.

[0013] According to this embodiment, the increase in size of the clamping mechanism in the up-down direction can be suppressed, compared with a structure that uses other elastic members such as a torsion spring in the clamping mechanism.

[0014] Additionally or alternatively to the preceding embodiments, the holding mechanism may comprise a cam portion that abuts against the clamping portion and urges the clamping portion toward the open position by rotating in an opening direction.

[0015] According to this embodiment, by providing the cam part in the holding mechanism, a user of the grinder can hold the clamp part in the open position against the biasing force of the elastic member without applying a large force.

[0016] In addition or alternatively to the preceding embodiments, the cam part may allow the clamping part to slide (displace) toward the closed position by rotating in a closing direction opposite to the opening direction. The holding mechanism may include a stop that stops the rotation of the cam part in the opening direction at a position where a sliding width (displacement width) of the clamping part toward the open position is maximized or begins to decrease after being maximized.

[0017] According to this embodiment, the stopper can hold the clamping part shifted far into the open position, making it easier for the user to place a sanding sheet.

[0018] In addition or alternatively to the preceding embodiments, the grinding part may have at least one receiving part that receives the compression spring. Each of the at least one receiving part may have a shorter length than a natural length of the compression spring in an extension direction of the compression spring.

[0019] According to this embodiment, during the manufacturing process of the sander, when the compression spring is accommodated in a compressed state within the receiving part, the compression spring can press the inner walls of the receiving part by the biasing force and is fixed within the receiving part. Thus, the manufacturing process of the sander can be facilitated.

[0020] Additionally or alternatively to the preceding embodiments, the clamping part may be configured to cover the upper side of the compression spring received in the at least one receiving part.

[0021] According to this embodiment, the compression spring can be protected from external factors.

[0022] In addition or alternatively to the preceding embodiments, the holding mechanism may include a cam portion that abuts against the clamping portion and urges the clamping portion toward the open position by rotating in an opening direction. The holding mechanism may include a lever portion configured to be (manually) actuated to rotate the cam portion. An outer contour of the lever portion may be located inside an outer contour of the blade placement surface in a surface direction when the cam portion is in the closed position.

[0023] According to this embodiment, during a grinding process using the grinding device, contact of the outer contour of the lever part with a workpiece or a wall projecting upwards from the workpiece is avoided.

[0024] In addition or alternatively to the preceding embodiments, the sander may have a suction part that sucks in sanding dust generated by sanding a workpiece by the sander. The sander may have a dust collection nozzle that directs the sucked-in sanding dust to the rear of the sander. The at least one clamping mechanism may have a rear clamping mechanism arranged rearward of the center of the sanding part. The rear clamping mechanism may be arranged in an area below the dust collection nozzle. The holding mechanism may have a cam part that abuts against the clamping part and presses the clamping part toward the open position by rotating in an opening direction. The holding mechanism of the rear clamping mechanism may have a lever part that is actuated to rotate the cam part.The lever part may include a portion having a height that increases in a direction away from a rotational axis of the cam part. A highest part of the lever part may have a height such that contact with the dust collection nozzle is avoided when the cam part is rotated.

[0025] According to this embodiment, the increase in size of the entire grinder can be suppressed by effectively utilizing the area under the dust collection port while allowing the rotation of the cam member.

[0026] An orbital sander (hereinafter referred to simply as sander 10) according to one non-limiting embodiment of the present disclosure will be described with reference to Fig. 1 to 15. The sanding device 10 described in this embodiment is also referred to as an orbital sander.

[0027] As in Fig. 1 and Fig. 2, the grinding device 10 has a drive mechanism 60 which has a drive shaft 66 (see Fig. 2), a housing 20 that houses the drive mechanism 60, a grinding part 30 connected to one end 661 of the drive shaft 66, and a handle 80 mounted on the housing 20. A central axis of the drive shaft 66 is also referred to as a drive axis A1.

[0028] The sander 10 further includes a handle 22 connected to the housing 20 and a battery mounting portion 50. The handle 22 extends in a direction intersecting the drive axis A1, with one end connected to the housing 20 and the other end being a free end.

[0029] In the present description, an extending direction of the drive axis A1 is defined as an up-down direction of the grinder 10. In the up-down direction, the side on which one end 661 of the drive shaft 66 and the grinding part 30 are connected is defined as a lower side, and the opposite side is defined as an upper side. A direction in which the handle 22 extends when viewed in the up-down direction is defined as a front-back direction of the grinder 10. In the front-back direction, the free end side of the handle 22 is defined as a rear side (rear side), and the opposite side is defined as a front side (front side). Further, a direction perpendicular to the front-back direction and the up-down direction is defined as a left-right direction of the grinder 10.In the left-right direction, the right side, viewed from the rear, is defined as a right side of the grinder 10, and the opposite side is defined as a left side of the grinder 10.

[0030] The housing 20 forms an outer shell of the grinder 10. A front end of the housing 20 is configured as a handle mounting part 100, to which the handle 80 is mounted. In this embodiment, the handle 80 is configured to be removable from the handle mounting part 100.

[0031] As in Fig. 2, the drive mechanism 60 includes an electric motor 61. The drive mechanism 60 is configured to drive the grinding part 30 by a rotational power of the electric motor 61. As shown in Fig. 2, in this embodiment, the electric motor 61 is a brushless motor, but it may be a brush motor.

[0032] The electric motor 61 includes a motor shaft 611 extending in the up-down direction and a motor body 612 having a stator and a rotor. The motor shaft 611 is rotatably supported by bearings 62, 63 fixed to the housing 20. The motor shaft 611 is arranged to be substantially at the center of the grinding part 30 when viewed in the up-down direction. A lower part of the motor shaft 611 is connected to the drive shaft 66. The drive shaft 66 is rotatably supported by the bearings 62, 63 fixed to the housing 20. The rotational power of the electric motor 61 is transmitted to the grinding part 30 via the motor shaft 611 and the drive shaft 66. A known power transmission mechanism (not shown) is provided for reducing the speed of the rotational power of the electric motor 61 and transmitting the rotational power to the grinding part 30.In this embodiment, a rotational axis of the motor shaft 611 coincides with the drive axis A1.

[0033] A fan 71 is mounted below the bearing 63 around the drive shaft 66. The fan 71 sucks grinding dust generated from a workpiece by grinding with the grinder 10. Specifically, a communication hole for communicating with the fan 71 is formed in a blade placement surface (blade support surface) 311. The grinding dust generated on the workpiece by grinding with the grinder 10 is sucked through the communication hole. A housing space (case space) for the fan 71 communicates with a dust collection nozzle (dust collection nozzle) 72. The dust collection nozzle 72 extends rearward from a lower rear end portion of the case 20. A fabric dust bag 82 for collecting dust is connected to the dust collection nozzle 72. The grinding dust sucked in by the fan wheel 71 is discharged from the dust collection nozzle 72 and stored in the dust bag 82.A resin dust bag (not shown) or a hose (not shown) for connecting to a dust collecting device (not shown) may also be attached to the dust collecting port 72.

[0034] As in Fig. 1 to 4, the grinding part 30 is arranged at the lowest part of the grinding device 10. The grinding part 30 includes a pad 31 and a base 32. A clamping mechanism 40 for clamping and fixing a sanding sheet (sandpaper) is arranged on the grinding part 30. The pad 31 and the base 32 have a generally rectangular shape having a longitudinal direction in the front-back direction when viewed from the up-down direction. The base 32 is arranged on the pad 31, and the base 32 and the pad 31 are connected by a bolt extending in the up-down direction. The clamping mechanism 40 is arranged at each of the front and rear parts of the base 32 across the drive mechanism 60. The clamping mechanisms 40 arranged at each of the front and rear parts of the base 32 have the same structure. As in Fig. As shown in Figure 4, the rear clamping mechanism 40 is disposed on the base 32 in an area below the dust collection port 72. A sandpaper (not shown) as the sanding sheet is attached to the sheet placement surface 311, which is a lower surface of the pad 31, using the clamping mechanism 40. The clamping mechanism 40 will be described in detail below.

[0035] As in Fig. 2, the grinding part 30 is connected to the drive shaft 66 via the bearing 64. A balancer (balance weight) 65 is fixed around a lower end of the drive shaft 66. The balancer 65 is fixed to the drive shaft 66 by a bolt that is threadedly engaged with a threaded hole formed in a lower end of the drive shaft 66. The bearing 64 is held between an upper part of the balancer 65 and the base 32. An inner ring of the bearing 64 is supported by a lower part of the balancer 65. The bearing 64 is arranged eccentrically to the drive shaft 66. The balancer 65 is formed to have a center of gravity at a position that is eccentric in a direction opposite to the eccentric direction of the bearing 64 relative to the drive shaft 66.This suppresses occurrence of vibration generated due to the structure that the bearing 64 is eccentric to the drive shaft 66.

[0036] The grinding part 30 is connected to the housing 20 via four supports (feet, legs, webs) 73. The supports 73 are configured to suppress vibration (specifically, fluttering (beating, swinging) in the up-down direction) generated by an orbital motion. In this embodiment, the supports 73 are respectively arranged in the vicinity of the four corners of the rectangular base 32. Each of the supports 73 has a generally cylindrical shape extending in the up-down direction. An upper end portion of the supports 73 is engaged with the housing 20 via an O-ring, and a lower end portion of the supports 73 is engaged with the base 32 via an O-ring. The support 73 can be tilted relative to the up-down direction while the O-rings are compressed (squeezed together).

[0037] The battery mounting part 50 is arranged at the front of the handle 22. The battery mounting part 50 is configured to mount a battery 55 as a power source of the electric motor 61 thereon by sliding it in the front-to-back direction. As shown in Fig. 2, the battery 55 mounted on the battery mounting part 50 is held above the grinding part 30 and the motor shaft 611. In this state, the motor shaft 611 is located in the vicinity of the center of the battery 55 when viewed in the up-down direction.

[0038] As in Fig. 2, a controller 52 is housed within the housing 20. In this embodiment, the controller 52 is disposed behind the motor body 612 and above the dust collection port 72. The controller 52 is electrically connected to terminals of the battery mounting portion 50 and the electric motor 61. The controller 52 includes various circuits and is configured to control operation of the electric motor 61 by controlling electrical power supplied from the battery 55 to the motor 61. The circuits include, for example, a high-temperature protection circuit, an overcurrent protection circuit, and an overdischarge protection circuit.

[0039] As in Fig. 1, Fig. 2 and Fig. As shown in Figure 4, a switch 25 is provided at a front upper end portion of the handle 22. The switch 25 is electrically connected to the controller 52. The switch 25 is provided for starting and stopping the electric motor 61. <Struktur des Klemmmechanismus>

[0040] The clamping mechanism 40 will now be described with reference to Fig. 1 to 15. First, the structure of the clamping mechanism 40 will be described, and then the function of the clamping mechanism 40 will be described.

[0041] As described above, the clamping mechanism 40 is disposed on each of the front and rear portions of the base 32 across the drive mechanism 60. As shown in Fig. 5, each of the clamping mechanisms 40 includes a cam lever 41, a clamping member 43, and compression springs 45.

[0042] As in Fig. 5 to 9, the cam lever 41 includes a lever part 412 and a cam part 42. A through hole 414 is formed through the cam part 42 in the cam lever 41. The cam lever 41 is fixed to the base 32 by inserting a screw 415 through the through hole 414 and threading it into engagement with a screw boss 321 formed on the base 32. The cam lever 41 can be rotated about the screw boss 321, which defines a rotation axis of the cam lever 41. The screw boss 321 also serves as a cam axis of the cam part 42. The lever part 412 serves as an operating part to be operated (manipulated) by a user to rotate the cam lever 41. The cam part 42 has a function of converting rotational motion into linear motion. The cam member 42 further has a function of converting an externally applied force into a rotational force for rotating the cam member 42 itself.The cam part 42 is received in a bottomed hole formed as a cam receiving part 323 in the base 32.

[0043] As in Fig. As shown in Figure 5, bottomed holes, each serving as a receiving part of an elastic member (elasticity member receiving part) 325, are formed in the base 32. The compression springs 45 are respectively received in the elasticity member receiving parts 325 so as to extend in the front-to-back direction. The length of the elasticity member receiving part 325 in the front-to-back direction is shorter than the natural length of the compression spring 45 (in other words, the natural length of the compression spring 45 is longer than the length of the elasticity member receiving part 325 in the front-to-back direction). Thus, the compression spring 45 is received in a compressed state in the elasticity member receiving part 325.

[0044] The clamping member 43 is arranged on the base 32. Specifically, the clamping member 43 is arranged between the cam lever 41 and the base 32 in the up-down direction. In this embodiment, the clamping member 43 is formed by sheet metal processing of a plate-like metal component. The clamping member 43 includes an upper clamping surface portion 431, spring contact portions 433, a cam contact portion 435, and a blade contact portion 437.

[0045] Each of the spring contact parts 433 is formed such that it extends downward from the upper clamping surface part 431. As shown in Fig. 5, Fig. 14 and Fig. 15, the spring contact part 433 is received in the elastic element receiving part 325 and abuts against one end of the compression spring 45. Thus, the spring contact part 433 is received in the elastic element receiving part 325 while being subjected to a biasing force of the compression spring 45. In Fig. 14 and Fig. In Fig. 15, the biasing force applied to the spring contact part 433 by the compression spring 45 is shown by an arrow. Specifically, the biasing force of the compression spring 45 is applied to the spring contact part 433 in a direction toward the inner side from the outer side of the base 32 in the front-rear direction. More specifically, in the front clamping member 43, the biasing force of the compression spring 45 is applied to the spring contact part 433 rearward from the front side, and in the rear clamping member 43, the biasing force of the compression spring 45 is applied to the spring contact part 433 forward from the rear side.

[0046] As in Fig. 14 and Fig. 15, the sheet contact part 437 is configured to hold a sanding sheet between the sheet contact part 437 and the base 32. The sheet contact part 437 is formed to extend downward from the upper clamping surface part 431. Further, the sheet contact part 437 is in a U-shape having an end portion bent toward a side surface part 327 of the base 32. The biasing force of the compression spring 45 is applied to the spring contact part 433 and transmitted to the sheet contact part 437 via the upper clamping surface part 431, and the sheet contact part 437 presses the side surface part 327 of the base 32. The sanding sheet is clamped by the force of the sheet contact part 437 pressing the side surface part 327 of the base 32.

[0047] As in Fig. 5, the cam contact portion 435 is formed to extend downward from the upper clamping surface portion 431 and is received in the cam receiving portion 323. The cam contact portion 435 abuts against the cam portion 42 and transmits to the clamping member 43 a rotational force applied to the cam lever 41 by a rotational movement of the cam lever 41 by the user as a force in the front-to-back direction.

[0048] The upper clamping surface portion 431 is configured to cover the compression springs 45 housed in the elastic element receiving portions 325 on the upper side of the base 32. With this configuration, the compression springs 45 can be protected from external factors. Specifically, the provision of the upper clamping surface portion 431 prevents direct contact of the compression springs 45 with external tools, components, dust, and liquid.

[0049] The function of the clamping mechanism 40 will now be described. Each of the positions of the clamping member 43, the cam lever 41 and the cam part 42, as shown in Fig. 8, Fig. 10 and Fig. 14, in which a sanding sheet can be held, is defined below as a "closed position." The state of the clamping mechanism 40 is defined as a "closed state" when the clamping member 43 is in the closed position. When the clamping mechanism 40 is in the closed state, the sheet contact portion 437 abuts against the side surface portion 327, which is a side surface of the base 32.

[0050] Each of the positions of the clamping member 43, the cam lever 41 and the cam part 42, as shown in Fig. 9, Fig. 13 and Fig. 15, in which the sanding sheet can be removed, is defined as an "open position." The state of the clamping mechanism 40 is defined as an "open state" when the clamping member 43 is in the open position. When the clamping mechanism 40 is in the open state, the sheet contact portion 437 is separated (removed) from the side surface portion 327 or the side surface of the base 32.

[0051] The function of the clamping mechanism 40 is described for a case where the cam lever 41 is rotated in the opening direction from the closed position as a starting point. As shown in Fig. 8, the lever part 412 extends in the left-right direction in the closed position. In the closed position, an outer contour of the lever part 412 is located inside an outer contour of the sheet placement surface 311 in the surface direction when viewed in the up-down direction. Specifically, the outer contour of the lever part 412 is located inside an outer contour of a left or right edge part (periphery part) of the sheet placement surface 311 when the clamping member 43 is in the closed position. Thus, during a grinding operation using the grinder 10, contact of the outer contour of the lever part 412 with a workpiece or a part or wall projecting from the workpiece is avoided. Accordingly, a user can perform a grinding operation even at the corners of the workpiece.

[0052] As in Fig. As shown in Figure 10, when the clamping mechanism 40 is in the closed state, a minor axis portion of the cam member 42 abuts against the cam contact portion 435. Furthermore, the biasing forces of the compression springs 45 are applied to the corresponding spring contact portions 433 in a direction toward the inner side from the outer side of the base 32 in the front-to-back direction. In other words, each of the compression springs 45 applies the biasing force for biasing the clamping member 43 toward the closed position. Fig. 10, the preload force of the compression spring 45 is shown by an arrow.

[0053] Furthermore, as described above, the biasing forces of the compression springs 45 are applied to the spring contact parts 433 and transmitted to the sheet contact part 437 via the upper clamping surface part 431, and the sheet contact part 437 presses the side surface part 327 of the base 32. The clamping member 43 holds the sanding sheet by the force of the sheet contact part 437 pressing the side surface part 327 of the base 32. The sanding sheet is fixed to the sheet placement surface 311 when the clamping members 43 of the clamping mechanism 40, which are arranged at the front and rear parts of the base 32, respectively, hold the front and rear ends of the sanding sheet.

[0054] In this embodiment, as shown in Fig. As shown in Fig. 14, a groove 328 extending in the left-right direction is formed in each of the front and rear side surface parts 327. The end part of the sheet contact part 437 abuts against the groove 328 of the side surface part 327 when the clamping mechanism 40 is in the closed state. With this structure, compared with a structure that does not have the groove 328 in the side surface part 327, the force of the clamping member 43 holding the sanding sheet in the closed state is increased due to a frictional force between the groove 328 and the sanding sheet clamped by the sheet contact part 437.

[0055] A user manually operates the lever part 412 to rotate the cam lever 41 toward the outside of the base 32 to rotate the clamping mechanism 40 from the closed state to the open state. The rotation direction of the cam lever 41 from the closed state to the open state is hereinafter defined as an opening direction, and the rotation direction of the cam lever 41 from the open state to the closed state is hereinafter defined as a closing direction.

[0056] As in Fig. As shown in FIG. 11, when the cam lever 41 is rotated in the opening direction, the cam portion 42 pushes the cam contact portion 435 and moves it toward the outside of the base 32 in the front-to-back direction. The clamp member 43 slides (is displaced) in a direction parallel to the sheet placement surface 311. As described above, the compression springs 45 bias the clamp member toward the closed position. Thus, the cam contact portion 435 of the clamp member 43 applies an urging force to the cam portion 42 toward the inner side in the front-to-back direction. The urging force of the cam contact portion 435 applied to the cam portion 42 toward the inner side in the front-to-back direction due to the biasing forces of the compression springs 45 is hereinafter referred to as an urging force PF.

[0057] The cam part 42 converts the pressing force PF into a rotational force in a rotational direction of the cam part 42. The rotational force applied to the cam part 42 due to the pressing force PF is hereinafter defined as a rotational force RF. In the state shown in Fig. As shown in Figure 11, the rotational force RF is applied to the cam part 42 in the closing direction. When the cam lever 41 is rotated in the opening direction, the user rotates the cam lever 41 against the rotational force RF applied in the closing direction. A circle enclosed by a dashed line in Fig. 11 corresponds to a track (orbit) of one end of the major axis of the cam member 42 when the cam member 42 is rotated. The rotational force RF is applied to the cam member 42 as a force in a tangential direction of the dashed circle.

[0058] As in Fig. As shown in Figure 12, when the cam portion 42 (the cam lever 41) is further rotated in the opening direction, a sliding width (movement length in the front-back direction) of the clamp member 43 toward the open position is maximized. In this state, a vector of the pressing force PF lies on a line connecting a contact point between the cam portion 42 and the cam contact portion 435 and the cam axis. Thus, the pressing force PF of the cam contact portion 435 pressing the cam portion 42 is not converted into the rotating force RF for rotating the cam portion 42. The state of the clamp mechanism 40 in this state will hereinafter also be referred to as a maximum open state. Each of the positions of the clamp member 43, the cam lever 41, and the cam portion 42 in the maximum open state will hereinafter be defined as a maximum open position.In this embodiment, the cam lever 41 can be rotated further in the opening direction in the maximum open position.

[0059] As in Fig. As shown in Figure 13, a stopper 324 is disposed on the cam receiving portion 323. The stopper 324 stops the cam portion 42 from further rotating in the opening direction at a predetermined position. The position at which the cam portion 42 is stopped from rotating by the stopper 324 is defined as a rotation stop position. When the cam portion 42 is rotated in the opening direction from the closed position as a starting point, the cam portion 42 is rotated from the closed position to the maximum open position and then to the rotation stop position (open position).

[0060] In this embodiment, when the cam portion 42 (the cam lever 41) is rotated in the opening direction, the stopper 324 stops the rotation of the cam portion 42 in the opening direction at a position where the sliding width of the clamp member 43 toward the open position begins to decrease after being maximized. With this structure, even if the user releases a hand from the cam lever 41 in the rotation stop position, the cam lever 41 and the clamp member 43 can stably maintain the open state, as will now be specifically described.

[0061] As described above, the cam part 42 has the function of converting the pressing force PF of the cam contact part 435, which presses the cam part 42, into the rotating force RF for rotating the cam part 42. The direction of the rotating force RF changes at the maximum open position of the cam part 42 as a boundary (change point, change point). Specifically, when the cam part 42 is between the closed position and the maximum open position, as shown in Fig. As shown in Figure 11, the pressing force PF of the cam contact part 435 pressing the cam part 42 is converted into the rotating force RF for rotating the cam part 42 in the closing direction. When the cam part 42 is between the maximum open position and the rotation stop position, as shown in Fig. 13, the pressing force PF of the cam contact part 435 pressing the cam part 42 is converted into the rotating force RF for rotating the cam part 42 in the opening direction.

[0062] Thus, as in Fig. As shown in Fig. 13, the rotational force RF for rotating the cam member 42 in the opening direction is applied to the cam member 42 in the rotation-stop position. Furthermore, the cam member 42 is stopped from rotating by the stopper 324. Accordingly, even if the user releases a hand from the cam lever 41 in the rotation-stop position, the rotational force RF for rotating the cam member 42 in the opening direction is applied to the cam member 42 in the rotation-stop position, so that the cam lever 41 and the clamp member 43 can maintain the open state.

[0063] Furthermore, since the rotational force RF for rotating the cam member 42 in the opening direction is applied to the cam member 42 in the rotation-stop position, even if a force smaller than the rotational force RF for rotating the cam member 42 in the opening direction is externally applied to the cam lever 41, the cam lever 41 is not rotated in the closing direction, so that the clamp mechanism 40 can maintain the open state. Specifically, even if a force smaller than the rotational force RF in the closing direction is applied to the cam lever 41, the clamp mechanism 40 can maintain the open state. Therefore, by providing this structure, the clamp mechanism 40 can stably maintain the open state. In this embodiment, the "open state" refers to the state (rotation-stop state) of the clamp mechanism 40 when the cam member 42 is stopped from rotating in the rotation-stop position by the stopper 324.

[0064] The following describes the function of the clamping mechanism 40 in the case where the clamping mechanism 40 is rotated in the closing direction from the open state (rotation stop state) as a starting point. As shown in Fig. As shown in Fig. 15, when the clamping mechanism 40 is in the open state or when the cam lever 41 (the cam part 42) is in the rotation stop position, a sufficient clearance for inserting an abrasive sheet is ensured between the sheet contact part 437 and the side surface part 327. When the user operates the lever part 412 to rotate the cam lever 41 in the closing direction after inserting the abrasive sheet between the sheet contact part 437 and the side surface part 327, the clamping member 43 slides to the closed position, and an end part of the abrasive sheet is clamped between the sheet contact part 437 and the side surface part 327 (the groove 328).

[0065] As described above, the direction of the rotational force RF changes at the maximum open position of the cam member 42 as a boundary (change point). Specifically, when the cam member 42 is between the closed position and the maximum open position, the pushing force PF of the cam contact member 435 pushing the cam member 42 is converted into the rotational force RF for rotating the cam member 42 in the closing direction. When the cam member 42 is between the maximum open position and the rotation stop position, the pushing force PF of the cam contact member 435 pushing the cam member 42 is converted into the rotational force RF for rotating the cam member 42 in the opening direction.Therefore, when the user rotates the cam lever 41 from the rotation stop position in the closing direction, the cam lever 41 is rotated against the rotational force RF acting on the cam part 42 to rotate the cam part 42 in the opening direction until the cam lever 41 is rotated from the rotation stop position to the maximum open position. When the user rotates the cam lever 41 in the closing direction slightly beyond the maximum open position, the direction of the rotational force RF changes, and the pushing force PF is converted into the rotational force RF to rotate the cam part 42 in the closing direction. The rotational force RF is applied to the cam part 42 in the closing direction in addition to a force applied to the cam lever 41 by the user to rotate the cam lever 41 in the closing direction. Therefore, the user can rotate the cam lever 41 to the closed position in the closing direction with a small force.

[0066] When the cam lever 41 is rotated in the closing direction beyond the maximum open position, the rotational force RF, which is caused to rotate the cam member 42 in the closing direction by the pressing force PF on the cam contact portion 435 pressing the cam member 42, is increased. Therefore, once the user rotates the cam lever 41 to a predetermined position beyond the maximum open position in the closing direction, the cam lever 41 is then rotated to the closed position without the user applying any force. In this case, the compression springs 45 must have a predetermined spring constant or greater.

[0067] As described above, the sander 10 of this embodiment includes the cam lever 41, which can hold the clamp member 43 in the open position against the biasing forces of the compression springs 45, so that the clamp member 43 can be held in the open position. Therefore, the user's work for placing a sanding sheet on the clamp mechanism 40 can be facilitated.

[0068] When the user of the sander 10 places a sanding sheet on the clamp member 43 held in the open position by the cam lever 41, and then operates the cam lever 41 to release the clamp member 43 from the open position, the clamp member 43 is moved to the closed position while the biasing force is applied by the pressing force PF in addition to the user's force for operating the cam lever 41 in the closing direction. Therefore, the sanding sheet can be held by the clamp member 43 by the user with a simple operation and a small force.

[0069] According to this embodiment, the clamping mechanisms 40 are respectively arranged on the front and rear sides across the center of the grinding part 30, so that the increase in size of the grinding device 10 in the left-right direction can be suppressed (prevented).

[0070] According to this embodiment, as shown in Fig. 4, the clamping mechanism 40 is arranged at the rear part of the base 32 in an area below the dust collection nozzle 72. The lever part 412 has a part having a height that increases (enlarges) in a direction away from the rotation axis of the cam part 42. A highest part (a part having the greatest height in the up-down direction) of the lever part 412 is configured such that an uppermost end 413 (see Fig. 7) does not touch the dust collection port 72 when the cam portion 42 is rotated. Thus, the increase in size of the entire sander 10 can be effectively suppressed by utilizing the area under the dust collection port 72 while allowing rotation of the cam portion 42.

[0071] According to this embodiment, the compression spring 45 extends in a direction parallel to the sheet placing surface 311. Thus, the increase in size of the clamping mechanism 40 in the up-down direction due to the presence of the compression spring 45 can be suppressed.

[0072] According to this embodiment, the compression spring 45 is used as the elastic element. Thus, the increase in size in the up-down direction can be suppressed (prevented) compared with a structure using other elastic elements such as a torsion spring.

[0073] According to this embodiment, the cam lever 41 (the cam portion 42) is used as the holding mechanism. Thus, a user of the grinder 10 can hold the clamping member 43 in the open position against the biasing force of the compression springs 45 without applying a large force.

[0074] According to this embodiment, the sander 10 includes the stopper 324 that stops rotation of the cam member 42 in the opening direction at a position (rotation stop position) where the sliding width of the clamp member 43 toward the open position begins to decrease after being maximized at the maximum open position. Thus, the stopper 324 can hold the clamp member 43 displaced far toward the open position, allowing the user to easily position the sanding sheet. Furthermore, the cam lever 41 and the clamp member 43 can maintain the open state even when the user releases the hand from the cam lever 41.

[0075] Furthermore, the rotational force RF for rotating the cam member 42 in the opening direction is applied to the cam member 42 in the rotation-stop position, and the cam member 42 is stopped from rotating by the stopper 324. Accordingly, even if the user releases the hand from the cam lever 41 in the rotation-stop position, the rotational force RF for rotating the cam member 42 in the opening direction is applied to the cam member 42 in the rotation-stop position, so that the cam lever 41 and the clamp member 43 can maintain the open state. Furthermore, since the rotational force RF for rotating the cam member 42 in the opening direction is applied to the cam member 42 in the rotation stop position, even if a smaller force than the rotational force RF for rotating the cam member 42 in the opening direction is externally applied to the cam lever 41, the cam lever 41 is not rotated in the closing direction, so that the clamp mechanism 40 can maintain the open state.Therefore, by providing this structure, the clamping mechanism 40 can stably maintain the open state.

[0076] In this embodiment, the length of the elastic member receiving part 325 in the front-to-back direction is shorter than the natural length of the compression spring 45. Thus, the compression spring 45 is received in a compressed state in the elastic member receiving part 325. Therefore, when the clamping mechanism 40 is assembled in the manufacturing process of the sander 10, the compression spring 45 can be fixed within the elastic member receiving part 325 without using a jig. However, in the case of using a torsion spring in the clamping mechanism, a jig is often required to mount the torsion spring in a compressed state. Compared with such a structure, the structure of this embodiment can facilitate the manufacturing work of the sander 10.

[0077] In this embodiment, the upper clamping surface portion 431 is configured to cover the compression spring 45, which is housed in the elastic member receiving portion 325, on the upper side of the base 32. With this configuration, the compression spring 45 can be protected from external factors. Specifically, providing the upper clamping surface portion 431 prevents direct contact of the compression spring 45 with external tools, components, dust, and liquid.

[0078] In the sander 10 of this embodiment, the outer contour of the lever part 412 is located inside the outer contour of the base 32 in the closed position when viewed in the up-down direction. Specifically, the outer contour of the lever part 412 is located inside the outer contour of the blade placement surface 311 in the surface direction when the clamping member 43 is in the closed position. Thus, during a sanding operation using the sander 10, contact of the outer contour of the lever part 412 with a workpiece or a part or wall protruding upward from the workpiece is avoided. Accordingly, a user can perform a sanding operation up to the corners of the workpiece.

[0079] Correspondences between the structures (features) of the above-described embodiment and the structures (features) of the present disclosure are as follows. However, the structures (features) of the above-described embodiment are merely exemplary and do not limit the structures (features) of the present disclosure.

[0080] The sander 10 is an example of a "sander." Sandpaper is an example of a "sanding sheet." The sheet placement surface 311 is an example of a "sheet placement surface." The sanding part 30 is an example of a "sanding part." The clamping mechanism 40 is an example of a "clamping mechanism." The clamping mechanism 40, which is located in front of the center of the sanding part 30, is an example of a "front clamping mechanism." The clamping mechanism 40, which is located in rear of the center of the sanding part 30, is an example of a "rear clamping mechanism." The clamping member 43 is an example of a "clamping part." The compression spring 45 is an example of an "elastic member." The compression spring 45 is an example of a "spring." The handle 22 is an example of a "handle." The cam lever 41 is an example of a "holding mechanism." The cam part 42 is an example of the "cam part." The lever part 412 is an example of the "lever part."The stopper 324 is an example of the "stop." The elastic element receiving part 325 is an example of the "receiving part." The fan wheel 71 is an example of the "suction part." The dust collection nozzle 72 is an example of the "dust collection nozzle." <Weitere Ausführungsformen>

[0081] Representative, non-limiting examples of the present disclosure have been described in detail above. This detailed description is merely intended to provide a person skilled in the art with further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the disclosure. The present disclosure can be implemented in a variety of configurations without departing from the scope of the disclosure. The technical features of the above embodiment corresponding to the above-described technical features may be appropriately replaced or combined to solve some or all of the above-described problems or to achieve some or all of the above-described advantageous effects. Any of the technical features may be omitted.

[0082] In the embodiment described above, the compression spring 45 was used as the elastic element, but other structures may be used instead. For example, an elastic rubber member may be used as the elastic element. As shown in Fig. As shown in Fig. 16, an elongated rubber member (rubber member) 46 is arranged in the elastic element receiving part 325. The rubber member 46 applies a biasing force for biasing the clamping member 43 toward the closed position in a direction parallel to the sheet placement surface 311. When the cam lever 41 is rotated toward the open position from the closed position as a starting point, as shown in Fig. As shown in Figure 17, the rubber member 46 deforms within the elastic member receiving portion 325 and applies the biasing force to the clamping member 43. The rubber member 46, as the elastic member, has the same function as the compression spring 45. With such a structure, the same effect as in the above-described embodiment can be achieved. Furthermore, the clamping mechanism 40 can be manufactured at a lower cost than in the above-described embodiment.

[0083] In another example, a tension spring can be used as the elastic element. As in Fig. 18, an elongated tension spring 47 is arranged in the elastic element receiving part 325. The tension spring 47 is arranged within the elastic element receiving part 325, but in a position different from the above-described embodiment. In this embodiment, the tension spring 47 is arranged closer to the center of the base 32 than the spring contact part 433 within the elastic element receiving part 325. With such an arrangement, the tension spring 47 biases the clamping member 43 toward the closed position by a tensile stress (preload force). The tensile stress is applied in a direction parallel to the blade placement surface 311. When the cam lever 41 is rotated in the opening direction from the closed position as a starting point, as shown in Fig.As shown in Figure 19, the tension spring 47 generates the tensile stress by being stretched within the elastic element receiving part 325 and applies the preload force to the clamping member 43. The tension spring 47, as the elastic element, has the same function as the compression spring 45. When the tension spring 47 is used as the elastic element, one end of the tension spring 47 must be fixed to the elastic element receiving part 325 and the other end to the spring contact part 433.

[0084] In the above-described embodiment, a structure may be adopted that does not include the pad 31. In this case, the lower surface of the base 32 serves as the "sheet placement surface."

[0085] In the above-described embodiment, the sander 10 may have only one clamping mechanism 40. For example, the sander 10 may have the clamping mechanism 40 of this embodiment at the rear of the base 32 and the other clamping mechanism, which is structurally different from the clamping mechanism 40 of this embodiment, at the front of the base 32. A conventional clamping mechanism may be used as the other clamping mechanism. For example, the clamping mechanism using a torsion spring may be employed.

[0086] The clamping mechanisms 40 can be arranged on the left and right parts of the base 32, respectively. The clamping mechanisms 40 can be arranged on the front, rear, left, and right parts of the base 32, respectively.

[0087] In the above-described embodiment, the stopper 324 may be arranged in such a position that it stops rotation of the cam part 42 in the opening direction at the maximum open position. With such a structure, the stopper 324 can hold the clamp member 43 displaced far toward the open position, thereby making it easy for the user to load a sanding sheet. As an alternative structure, the stopper 324 may be arranged in such a position that it stops rotation of the cam part 42 in the opening direction at a predetermined position after the sliding width of the clamp member 43 is maximized toward the open position and begins to decrease as the cam part 42 (the cam lever 41) is rotated toward the open position.Specifically, in this sander, the holding mechanism may include the stopper that stops rotation of the cam member in the opening direction after the sliding width of the clamp member toward the open position is maximized and begins to decrease, where the rotation direction of the cam member for pushing the clamp member toward the open position is defined as the opening direction, and the rotation direction of the cam member for allowing the clamp member to slide toward the closed position is defined as the closing direction. With such a structure, the cam lever 41 and the clamp member 43 can maintain the open state even when the user releases their hand from the cam lever 41. Furthermore, the stopper 324 can hold the clamp member 43 displaced far toward the open position, making it easier for the user to load a sanding sheet.

[0088] In the above-described embodiment, the clamping mechanism 40 may include only one elastic member. This structure can be provided by disposing the elastic member in the vicinity of a central portion of the clamping mechanism 40 other than the cam portion 42.

[0089] In the embodiment described above, the cam lever 41 is used as the holding mechanism, but other structures may be used instead. For example, a rod-like member configured to hold the clamp member 43 in the open position against the biasing force of the elastic member may be disposed in the cam receiving part 323. When the clamp member 43 is moved to the open position, the rod-like member is located between the clamp member 43 (a part corresponding to the cam contact part 435) and a wall of the cam receiving part 323 in abutment with these parts, and holds the clamp member 43 in the open position against the biasing force of the elastic member. This can simplify the structure.

[0090] The disclosure is not limited to any one of the above-described embodiments and the other embodiments or modifications described above, but may be implemented in a variety of configurations without departing from the scope of the disclosure. For example, the technical features of each of the above-described embodiments and their modifications may be replaced or appropriately combined to solve some or all of the problems described above or to achieve some or all of the advantageous effects described above. Any of the technical features may be appropriately omitted unless the technical feature is designated as essential in the present description.

[0091] It is explicitly emphasized that all features disclosed in the description and / or the claims are to be considered separate and independent of each other for the purpose of the original disclosure as well as for the purpose of limiting the claimed invention, regardless of the feature combinations in the embodiments and / or the claims. It is explicitly stated that all range specifications or specifications of groups of units disclose every possible intermediate value or subgroup of units for the purpose of the original disclosure as well as for the purpose of limiting the claimed invention, in particular also as a limit of a range specification. LIST OF REFERENCE SYMBOLS

[0092] 10: Grinder, 20: Housing, 22: Handle, 25: Switch, 30: Grinding part, 31: Cushion, 32: Base, 40: Clamping mechanism, 41: Cam lever, 42: Cam part, 43: Clamping component, 45: Compression spring, 46: Rubber component, 47: Extension spring, 50: Battery mounting part, 52: Controller, 55: Battery, 60: Drive mechanism, 61: Electric motor, 62: Bearing, 63: Bearing, 64: Bearing, 65: Balance piece. 66: Drive shaft, 71: Fan wheel, 72: Dust collection nozzle, 73: Support, 80: Handle, 82: Dust bag, 100: Handle mounting part, 311: Blade placement surface, 321: Screw boss, 323: Cam receiving part, 324: Stop, 325: Elastic element receiving part, 327: Side surface part, 328: Groove, 412: Lever part, 413: Top end, 414: Through hole, 415: Screw, 431: Upper clamping surface part, 433: Spring contact part, 435: Cam contact part, 437: Blade contact part, 611: Motor shaft, 612: Motor body, 661: One end of the drive shaft, A1: Drive axis, PF: Pushing force, RF: Rotating force QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2010 - 207 964 A [0002, 0003] JP H2-15 256 U [0002, 0003]

Claims

[1] Grinding machine, with a grinding part having a flat sheet placement surface on which a sanding sheet can be placed, and at least one clamping mechanism configured to hold the sanding sheet to the sanding part, in which which has at least one clamping mechanism, a clamping part configured to hold the sanding sheet and to be displaced in a direction parallel to the sheet placing surface between a closed position for holding the sanding sheet on a side surface of the sanding part and an open position for allowing removal of the sanding sheet, at least one elastic member applying a biasing force for biasing the clamping member toward the closed position in a direction parallel to the sheet placing surface, and a holding mechanism configured to hold the clamping part in the open position against the preload force, and the clamping part can hold the sanding sheet when the holding mechanism is released from holding the clamping part in the open position. [2] Grinding device according to claim 1, further comprising an elongated handle, in which a direction perpendicular to the blade placement surface defines an up-down direction of the grinding device, a direction in which the handle extends when viewed in the up-down direction, defining a front-back direction of the grinder of the grinder, and which has at least one clamping mechanism, a front clamping mechanism arranged in front of a center of the grinding part, and has a rear clamping mechanism located at the rear of the center of the grinding part. [3] A grinding apparatus according to claim 1 or 2, wherein each of said at least one elastic member is an elongated spring, and said elongated spring extends in a direction parallel to said sheet placing surface. [4] A grinding device according to any one of claims 1 to 3, wherein each of said at least one resilient member is an elongated compression spring. [5] A grinding device according to any one of claims 1 to 4, wherein the holding mechanism has a cam part which abuts against the clamping part and urges the clamping part toward the open position by rotating in an opening direction. [6] Grinding device according to claim 5, in which the cam part allows the clamping part to slide to the closed position by rotating in a closing direction opposite to the opening direction, and the holding mechanism has a stopper that stops rotation of the cam member in the opening direction at a position at which a sliding width of the clamp member toward the open position is maximized or begins to decrease after the maximization. [7] Grinding device according to claim 4, in which the grinding part has at least one receiving part which receives the compression spring, and each of the at least one receiving part has a shorter length than a natural length of the compression spring in an extension direction of the compression spring. [8] The grinding device according to claim 7, wherein the clamping part is configured to cover an upper side of the compression spring received in the at least one receiving part. [9] Grinding device according to one of claims 5 to 8, in which the holding mechanism a cam part which abuts against the clamping part and pushes the clamping part towards the open position by rotating in an opening direction, and the lever part is operated to rotate the cam part, and an outer contour of the lever part is located inside an outer contour of the sheet placing surface in a surface direction when the clamping part is in the closed position. [10] Grinding device according to one of claims 5 to 9, with a suction part that sucks in grinding dust generated by a workpiece when grinding with the grinder, and a dust collection nozzle that directs the sucked-in grinding dust to the rear of the grinding machine, in which the at least one clamping mechanism has a rear clamping mechanism arranged rearward of the center of the grinding part, the rear clamping mechanism is located in an area below the dust collection nozzle, the holding mechanism a cam part which abuts against the clamping part and presses the clamping part towards the open position by rotating in an opening direction, and has a lever part which is actuated to rotate the cam part, the lever part has a part having a height that increases upward in a direction away from a rotational axis of the cam part, and a highest part of the lever part has a height such that contact with the dust collection nozzle is avoided when the cam part is rotated.

Images