SANDER

Abstract

The sander includes a sanding part having a planar sheet placement surface on which a sanding sheet can be set, and a clamping mechanism configured to hold the sanding sheet on the sanding part. The clamping mechanism includes a clamping part configured to hold the sanding sheet and to be slid in a direction parallel to the sheet placement surface between a closed position to hold the sanding sheet and an open position to allow removal of the sanding sheet, an elastic element that applies a biasing force of biasing the clamping part toward the closed position, in a direction parallel to the sheet placement surface, and a holding mechanism configured to hold the clamping part in the open position against the biasing force. 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.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese patent application no. 2023-140752 filed on Aug. 31, 2023, the contents of which are fully incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a sander.

BACKGROUND

Sanders are known which have a clamping mechanism for holding a sanding sheet. Japanese Unexamined Patent Application Publication No. 2010-207964 (JP2010-207964A) discloses a sander having a torsion spring, a clamp lever and a clamping member. The clamp lever is formed on one end of the torsion spring, and the clamping member is connected to the other end of the torsion spring. When the clamp lever is locked to a projecting locking part by a user while the torsion spring maintains the biasing force, the clamping member holds the sanding sheet by the biasing force. Japanese Unexamined Utility Model Application Publication No. H2-15256 (JP H2-15256U) disclose a sander in which the clamping member is moved up and down by user's operation of the clamp lever to hold and release the sanding sheet. The clamping member holds the sanding sheet by being biased by the torsion spring.

SUMMARY

In the sander disclosed in JP2010-207964A, it is necessary for a user to lift the clamp lever and lock the clamp lever to the projecting locking part against the biasing force of the torsion spring in order to hold the sanding sheet. Therefore, the operability of the clamp lever is poor in operating the clamp lever while pressing the sanding sheet with a hand of the user. In the sander disclosed in JP H2-15256U, the clamping member and the torsion spring are moved up and down, so that the structure of the clamping mechanism in the up-down direction is increased in size.

It is accordingly an object of the present disclosure to provide improvement relating to a clamping mechanism in a sander.

According to one non-limiting aspect of the present disclosure, a sander is provided that has a sanding part and at least one clamping mechanism. The sanding part has a planar sheet placement surface on which a sanding sheet can be set. The at least one clamping mechanism is configured to hold the sanding sheet on the sanding part. The at least one clamping mechanism includes a clamping part, at least one elastic element and a holding mechanism. The clamping part is configured to hold the sanding sheet and to be slid in a direction parallel to the sheet placement surface between a closed position to hold the sanding sheet on a side surface of the sanding part and an open position to allow removal of the sanding sheet. The at least one elastic element applies a biasing force of biasing 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 sander, 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.

According to this aspect, when the user of the sander sets a sanding sheet on the clamping part held in the open position by the holding mechanism and then manipulates the holding mechanism to release holding of the clamping part in the open position, the clamping part is moved to the closed position while the biasing force of the elastic element is applied in addition to the user's force of operating the holding mechanism. Therefore, the sanding sheet can be held by the clamping member with user's simple operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a right side view of a sander.

FIG. 2 is a longitudinal sectional view of the sander, for illustrating the outline of the internal structure.

FIG. 3 is a perspective view showing the front side of the sander.

FIG. 4 is a perspective view showing the rear side of the sander.

FIG. 5 is a disassembled, perspective view for illustrating 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 relation between a cam part and a clamping member in the closed state.

FIG. 11 is an explanatory view showing the relation between the cam part and the clamping member when the cam part is rotated in the opening direction from the closed position as a starting point.

FIG. 12 is an explanatory view showing the relation between the cam part and the clamping member in the maximum open state.

FIG. 13 is an explanatory view showing the relation between the cam 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 clamping mechanism using a rubber member as the elastic element.

FIG. 17 is an explanatory view showing the open state of the clamping mechanism using the rubber member as the elastic element.

FIG. 18 is an explanatory view showing the closed state of a clamping mechanism using a tension spring as the elastic element.

FIG. 19 is an explanatory view showing the open state of the clamping mechanism using the tension spring as the elastic element.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In one non-limiting embodiment according to the present disclosure, the sander may have an elongate handle. A direction orthogonal to the sheet placement surface defines an up-down direction of the sander, and a direction in which the handle extends when viewed from the up-down direction defines a front-rear direction of the sander. The at least one clamping mechanism may include a front clamping mechanism arranged frontward of a center of the sanding part. The at least one clamping mechanism may include a rear clamping mechanism arranged rearward of the center of the sanding part.

According to this embodiment, the front and rear clamping mechanisms are arranged in the same direction as the extending direction of the handle, so that the size increase of the sander in the left-right direction can be suppressed.

In addition or in the alternative to the preceding embodiment, each of the at least one elastic element may be an elongate spring. The spring may extend in a direction parallel to the sheet placement surface.

According to this embodiment, the spring extends in a direction parallel to the sheet placement surface, so that the size increase of the clamping mechanism in the up-down direction due to the presence of the spring can be suppressed.

In addition or in the alternative to the preceding embodiments, each of the at least one elastic element may be an elongate compression spring. The elongate spring may extend in a direction parallel to the sheet placement surface.

According to this embodiment, the size increase of the clamping mechanism in the up-down direction can be suppressed compared with a structure using other elastic elements such as a torsion spring in the clamping mechanism.

In addition or in the alternative to the preceding embodiments, the holding mechanism may include a cam part that abuts on the clamping part and presses the clamping part toward the open position by rotating in an opening direction.

According to this embodiment, by provision of the cam part in the holding mechanism, a user of the sander can hold the clamping part in the open position against the biasing force of the elastic element without using a large force.

In addition or in the alternative to the preceding embodiments, the cam part may allow the clamping part to slide to the closed position by rotating in a closing direction opposite to the opening direction. The holding mechanism may include a stopper that stops rotation of the cam part in the opening direction in a position where a sliding width of the clamping part toward the open position is maximized or starts decreasing after being maximized.

According to this embodiment, the stopper can hold the clamping part widely slid to the open position, which makes it easy for the user to set a sanding sheet.

In addition or in the alternative to the preceding embodiments, the sanding part may include at least one housing part that houses the compression spring. Each of the at least one housing part may have a shorter length than a natural length of the compression spring in an extending direction of the compression spring.

According to this embodiment, in the manufacturing work of the sander, when the compression spring is housed in a compressed state within the housing part, the compression spring presses inner walls of the housing part by the biasing force and is fixed within the housing part. Thus, the manufacturing work of the sander can be facilitated.

In addition or in the alternative to the preceding embodiments, the clamping part may be configured to cover the upper side of the compression spring housed in the at least one housing part.

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

In addition or in the alternative to the preceding embodiments, the holding mechanism may include a cam part that abuts on the clamping part and presses the clamping part toward the open position by rotating in an opening direction. The holding mechanism may include a lever part that is configured to be manipulated to rotate the cam part. An outer contour of the lever part may be located inward of an outer contour of the sheet placement surface in a surface direction when the clamping part is in the closed position.

According to this embodiment, in sanding operation using the sander, contact of the outer contour of the lever part with a workpiece or a wall rising upward from the workpiece is avoided.

In addition or in the alternative to the preceding embodiments, the sander may have a suction part that sucks sanding dust generated from a workpiece by sanding with the sander. The sander may have a dust collecting nozzle that discharges the sucked sanding dust rearward in the sander. The at least one clamping mechanism may include a rear clamping mechanism arranged rearward of the center of the sanding part. The rear clamping mechanism may be arranged in a region under the dust collecting nozzle. The holding mechanism may include a cam part that abuts on 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 include a lever part that is operated to rotate the cam part. The lever part may have a part having a height increasing upward in a direction away from a rotational axis of the cam part. A highest part of the lever part may have such a height as to avoid contact with the dust collecting nozzle when the cam part is rotated.

According to this embodiment, the size increase of the whole sander can be suppressed by effectively utilizing the region under the dust collecting nozzle while allowing rotation of the cam part.

An orbital sander (hereinafter simply referred to as a sander 10) according to one non-limiting embodiment of the present disclosure is now described with reference to FIGS. 1 to 15. The sander 10 exemplified in this embodiment is also referred to as a finishing sander.

As shown in FIGS. 1 and 2, the sander 10 includes a driving mechanism 60 having a driving shaft 66 (see FIG. 2), a housing 20 that houses the driving mechanism 60, a sanding part 30 connected to one end 661 of the driving shaft 66, and a grip 80 mounted to the housing 20. A central axis of the driving shaft 66 is also referred to as a driving axis A1.

The sander 10 further includes a handle 22 connected to the housing 20, and a battery mounting part 50. The handle 22 extends in a direction crossing the driving axis A1, with one end connected to the housing 20 and the other end free.

In the following description, an extending direction of the driving shaft A1 is defined as an up-down direction of the sander 10. In the up-down direction, the side on which the one end 661 of the driving shaft 66 and the sanding 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 from the up-down direction is defined as a front-rear direction of the sander 10. In the front-rear direction, the free end side of the handle 22 is defined as a rear side, and the opposite side is defined as a front side. Further, a direction orthogonal to the front-rear direction and the up-down direction is defined as a left-right direction of the sander 10. In the left-right direction, the right side as viewed from the rear is defined as a right side of the sander 10, and the opposite side is defined as a left side of the sander 10.

The housing 20 forms an outer shell of the sander 10. A front end of the housing 20 is configured as a grip mounting part 100 to which the grip 80 is mounted. In this embodiment, the grip 80 is configured to be detachable from the grip mounting part 100.

As shown in FIG. 2, the driving mechanism 60 includes an electric motor 61. The driving mechanism 60 is configured to drive the sanding part 30 by rotating 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 motor with a brush.

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 located substantially at the center of the sanding part 30 when viewed from the up-down direction. A lower part of the motor shaft 611 is connected to the driving shaft 66. The driving shaft 66 is rotatably supported by the bearings 62, 63 fixed to the housing 20. The rotating power of the electric motor 61 is transmitted to the sanding part 30 via the motor shaft 611 and the driving shaft 66. A known power transmitting mechanism (not shown) is provided to reduce the speed of the rotating power of the electric motor 61 and transmit the rotating power to the sanding part 30. In this embodiment, a rotational axis of the motor shaft 611 coincides with the driving axis A1.

A fan 71 is mounted under the bearing 63 around the driving shaft 66. The fan 71 sucks sanding dust that is generated from a workpiece by sanding with the sander 10. More specifically, a communication hole for communication with the fan 71 is formed in a sheet placement surface 311. The sanding dust generated from the workpiece by sanding with the sander 10 is sucked through the communication hole. A housing space for the fan 71 communicates with a dust collecting nozzle 72. The dust collecting nozzle 72 extends rearward from a lower rear end part of the housing 20. A fabric dust bag 82 for dust collection is connected to the dust collecting nozzle 72. The sanding dust sucked by the fan 71 is discharged from the dust collecting nozzle 72 and stored in the dust bag 82. A resin dust bag (not shown), or a hose (not shown) for connection with a dust collecting machine (not shown) can also be attached to the dust collecting nozzle 72.

As shown in FIGS. 1 to 4, the sanding part 30 is arranged at the lowermost part of the sander 10. The sanding part 30 includes a pad 31 and a base 32. A clamping mechanism 40 for clamping and fixing a sanding sheet is disposed on the sanding part 30. The pad 31 and the base 32 have a generally rectangular shape having a longitudinal direction in the front-rear 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 on each of the front and rear parts of the base 32 across the driving mechanism 60. The clamping mechanisms 40 respectively arranged on the front and rear parts of the base 32 have the same structure. As shown in FIG. 4, the rear clamping mechanism 40 on the base 32 is arranged in a region under the dust collecting nozzle 72. Sanding paper (not shown) as the sanding sheet is attached on the sheet placement surface 311, which is a bottom surface of the pad 31, by utilizing the clamping mechanisms 40. The clamping mechanisms 40 will be described in detail below.

As shown in FIG. 2, the sanding part 30 is connected to the driving shaft 66 via the bearing 64. A balancer 65 is fixed around a lower end of the driving shaft 66. The balancer 65 is fixed to the driving shaft 66 by a bolt being threadedly engaged with a threaded hole formed in a lower end of the driving 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 driving shaft 66. The balancer 65 is shaped to have a center of gravity at a position eccentric in a direction opposite to the eccentric direction of the bearing 64 relative to the driving shaft 66. This suppresses occurrence of vibration caused due to the structure that the bearing 64 is eccentric to the driving shaft 66.

The sanding part 30 is connected to the housing 20 via four feet 73. The feet 73 are configured to suppress vibration (particularly, flapping in the up-down direction) caused by orbital motion. In this embodiment, the feet 73 are respectively arranged in the vicinity of four corners of the rectangular base 32. Each of the feet 73 has a generally cylindrical shape extending in the up-down direction. An upper end part of the foot 73 is engaged with the housing 20 via an O-ring, and a lower end part of the foot 73 is engaged with the base 32 via an O-ring. The foot 73 can be tilted relative to the up-down direction while compressing the O-rings.

The battery mounting part 50 is arranged in front of the handle 22. The battery mounting part 50 is configured such that a battery 55 as a power source of the electric motor 61 is mounted thereto by sliding in the front-rear direction. As shown in FIG. 2, the battery 55 mounted to the battery mounting part 50 is held above the sanding 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 from the up-down direction.

As shown in FIG. 2, a controller 52 is housed within the housing 20. In this embodiment, the controller 52 is arranged behind the motor body 612 and above the dust collecting nozzle 72. The controller 52 is electrically connected to terminals of the battery mounting part 50 and the electric motor 61. The controller 52 has various circuits and is configured to control operation of the electric motor 61 by controlling electric power supplied from the battery 55 to the electric motor 61. The circuits include, for example, a high temperature protection circuit, an overcurrent protection circuit and an overdischarge protection circuit.

As shown in FIGS. 1, 2 and 4, a switch 25 is provided on a front end upper part of the handle 22. The switch 25 is electrically connected to the controller 52. The switch 25 is provided to start and stop the electric motor 61

Structure of the Clamping Mechanism

The clamping mechanism 40 is now described with reference to FIGS. 1 to 15. First, the structure of the clamping mechanism 40 is described, and then the function of the clamping mechanism 40 is described.

As described above, the clamping mechanism 40 is arranged on each of the front and rear parts of the base 32 across the driving mechanism 60. As shown in FIG. 5, each of the clamping mechanisms 40 has a cam lever 41, a clamping member 43 and compression springs 45.

As shown in FIGS. 5 to 9, the cam lever 41 has 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 fastened to the base 32 by a screw 415 being inserted through the through hole 414 and threadedly engaged with a boss 321 formed on the base 32. The cam lever 41 can be turned around the boss 321 that defines a rotational axis of the cam lever 41. The boss 321 also serves to define 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 turn the cam lever 41. The cam part 42 has a function of converting rotational motion into linear motion. The cam part 42 further has a function of converting externally applied force into rotational force for rotating the cam part 42 itself. The cam part 42 is housed in a bottomed hole formed as a cam housing part 323 in the base 32.

As shown in FIG. 5, bottomed holes, each serving as an elastic element housing part 325, are formed in the base 32. The compression springs 45 are housed in the elastic element housing parts 325, respectively, so as to extend in the front-rear direction. The length of the elastic element housing part 325 in the front-rear 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 elastic element housing part 325 in the front-rear direction.) Thus, the compression spring 45 is housed in a compressed state in the elastic element housing part 325.

The clamping member 43 is disposed on the base 32. Specifically, the clamping member 43 is disposed 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 working of a metal plate-like member. The clamping member 43 has a clamp upper surface part 431, spring contact parts 433, a cam contact part 435 and a sheet contact part 437.

Each of the spring contact parts 433 is formed to extend downward from the clamp upper surface part 431. As shown in FIGS. 5, 14 and 15, the spring contact part 433 is housed in the elastic element housing part 325 and abuts on one end of the compression spring 45. Thus, the spring contact part 433 is housed in the elastic element housing part 325 while being subjected to a biasing force of the compression spring 45. In FIGS. 14 and 15, the biasing force being 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.

As shown in FIGS. 14 and 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 clamp upper surface part 431. Further, the sheet contact part 437 is U-shaped having an end part 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 clamp upper 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.

As shown in FIG. 5, the cam contact part 435 is formed to extend downward from the clamp upper surface part 431, and housed in the cam housing part 323. The cam contact part 435 abuts on the cam part 42 and transmits to the clamping member 43 a rotational force, which is applied to the cam lever 41 by user's turning operation of the cam lever 41, as a force in the front-rear direction.

The clamp upper surface part 431 is configured to cover the compression springs 45 housed in the elastic element housing parts 325 on the upper side of the base 32. With this configuration, the compression springs 45 can be protected from external factors. Specifically, provision of the clamp upper surface part 431 avoids direct contact of the compression springs 45 with external tools, members, dust and liquid.

The function of the clamping mechanism 40 is now described. Each of the positions of the clamping member 43, the cam lever 41 and the cam part 42 as shown in FIGS. 8, 10 and 14 in which a sanding sheet can be held is hereinafter defined 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 part 437 abuts on the side surface part 327 that is a side surface of the base 32.

Each of the positions of the clamping member 43, the cam lever 41 and the cam part 42 as shown in FIGS. 9, 13 and 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 part 437 is separated from the side surface part 327 or the side surface of the base 32.

The function of the clamping mechanism 40 is described as to the case where the cam lever 41 is turned in the opening direction from the closed position as a starting point. As shown in FIG. 8, the lever part 412 in the closed position extends in the left-right direction. In the closed position, an outer contour of the lever part 412 is located inward of an outer contour of the sheet placement surface 311 in the surface direction, when viewed from the up-down direction. More specifically, the outer contour of the lever part 412 is located inward of an outer contour of a left or right edge part of the sheet placement surface 311 when the clamping member 43 is in the closed position. Thus, in sanding operation using the sander 10, contact of the outer contour of the lever part 412 with a workpiece or a part or wall rising upward from the workpiece is avoided. As a result, a user can perform a sanding operation even on the corners of the workpiece.

As shown in FIG. 10, when the clamping mechanism 40 is in the closed state, a minor axis part of the cam part 42 abuts on the cam contact part 435. Further, the biasing forces of the compression springs 45 are applied to the corresponding spring contact parts 433 in a direction toward the inner side from the outer side of the base 32 in the front-rear direction. In other words, the compression springs 45 each applies to the clamping member 43 the biasing force of biasing the clamping member 43 toward the closed position. In FIG. 10, the biasing force of the compression spring 45 is shown by an arrow.

Further, 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 clamp upper 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 mechanisms 40 that are arranged on the front and rear parts of the base 32 respectively hold front and rear ends of the sanding sheet.

In this embodiment, as shown in FIG. 14, a groove 328 is formed extending in the left-right direction in each of the front and rear side surface part 327. The end part of the sheet contact part 437 abuts on 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 not having the groove 328 in the side surface part 327, the force of the clamping member 43 holding the sanding sheet is increased in the closed state due to a frictional force between the groove 328 and the sanding sheet clamped by the sheet contact part 437.

A user manipulates the lever part 412 to turn the cam lever 41 toward the outer side of the base 32 in order to turn the clamping mechanism 40 from the closed state into the open state. The turning direction of the cam lever 41 from the closed state to the open state is hereinafter defined as an opening direction, and a turning direction of the cam lever 41 from the open state to the closed state is defined as a closing direction.

As shown in FIG. 11, when the cam lever 41 is turned in the opening direction, the cam part 42 presses and moves the cam contact part 435 toward the outer side of the base 32 in the front-rear direction. The clamping member 43 slides in a direction parallel to the sheet placement surface 311. As described above, the compression springs 45 bias the clamping member toward the closed position. Thus, the cam contact part 435 of the clamping member 43 applies a pressing force to the cam part 42 toward the inner side in the front-rear direction. The pressing force of the cam contact part 435 that is applied to the cam part 42 toward the inner side in the front-rear direction due to the biasing forces of the compression springs 45 is hereinafter defined as a pressing force PF.

The cam part 42 converts the pressing force PF into a force in a rotational direction of the cam part 42. The rotational force that is 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. 11, the rotational force RF is applied to the cam part 42 in the closing direction. When turning the cam lever 41 in the opening direction, a user turns the cam lever 41 against the rotational force RF applied in the closing direction. A circle shown by a broken line in FIG. 11 corresponds to a track of an end of the major axis of the cam part 42 when the cam part 42 is rotated is shown by a broken line. The rotational force RF is applied to the cam part 42 as a force in a tangential direction of the broken-line circle.

As shown in FIG. 12, when the cam part 42 (the cam lever 41) is further rotated in the opening direction, a sliding width (a travel length in the front-rear direction) of the clamping member 43 toward the open position is maximized. In this state, a vector of the pressing force PF exists on a line connecting a contact point between the cam part 42 and the cam contact part 435 and the cam axis. Thus, the pressing force PF of the cam contact part 435 pressing the cam part 42 is not converted into the rotational force RF of rotating the cam part 42. The state of the clamping mechanism 40 in this state is hereinafter also referred to as a maximum open state. Each of the positions of the clamping member 43, the cam lever 41 and the cam part 42 in the maximum open state is hereinafter defined as a maximum open position. In this embodiment, the cam lever 41 in the maximum open position can be further turned in the opening direction.

As shown in FIG. 13, a stopper 324 is disposed in the cam housing part 323. The stopper 324 stops the cam part 42 at a prescribed position from further rotating in the opening direction. The position where the cam part 42 is stopped from rotating by the stopper 324 is defined as a rotation stop position. When the cam part 42 is rotated in the opening direction from the closed position as a starting point, the cam part 42 is rotated from the closed position to the maximum open position and then to the rotation stop position (open position).

In this embodiment, when the cam part 42 (the cam lever 41) is rotated in the opening direction, the stopper 324 stops rotation of the cam part 42 in the opening direction in a position where the sliding width of the clamping member 43 toward the open position starts decreasing 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 clamping member 43 can stably maintain the open state, which is now specifically described below.

As described above, the cam part 42 has a function of converting the pressing force PF of the cam contact part 435 pressing the cam part 42, into the rotational force RF of rotating the cam part 42. The direction of the rotational force RF changes at the maximum open position of the cam part 42 as a boundary (change point). More specifically, when the cam part 42 is located between the closed position and the maximum open position as shown in FIG. 11, the pressing force PF of the cam contact part 435 pressing the cam part 42 is converted into the rotational force RF of rotating the cam part 42 in the closing direction. When the cam part 42 is located 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 rotational force RF of rotating the cam part 42 in the opening direction.

Thus, as shown in FIG. 13, the rotational force RF of rotating the cam part 42 in the opening direction is applied to the cam part 42 in the rotation stop position. Further, the cam part 42 is stopped from rotating by the stopper 324. As a result, even if the user releases a hand from the cam lever 41 in the rotation stop position, the rotational force RF of rotating the cam part 42 in the opening direction is applied to the cam part 42 in the rotation stop position, so that the cam lever 41 and the clamping member 43 can maintain the open state.

Further, since the rotational force RF of rotating the cam part 42 in the opening direction is applied to the cam part 42 in the rotation stop position, even if a smaller force than the rotational force RF of rotating the cam part 42 in the opening direction is externally applied to the cam lever 41, the cam lever 41 is not turned in the closing direction, so that the clamping mechanism 40 can maintain the open state. More specifically, even if a smaller force in the closing direction than the rotational force RF is applied to the cam lever 41, the clamping mechanism 40 can maintain the open state. Therefore, by provision of this structure, the clamping mechanism 40 can stably maintain the open state. In this embodiment, the “open state” refers to the state (rotation stop state) of the clamping mechanism 40 when the cam part 42 is stopped from rotating in the rotation stop position by the stopper 324.

Next, the function of the clamping mechanism 40 is described as to the case where the clamping mechanism 40 is turned in the closing direction from the open state (rotation stop state) as a starting point. 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 distance is ensured for insertion of a sanding sheet between the sheet contact part 437 and the side surface part 327. When the user operates the lever part 412 to turn the cam lever 41 in the closing direction after inserting the sanding 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 sanding sheet is clamped between the sheet contact part 437 and the side surface part 327 (the groove 328).

As described above, the direction of the rotational force RF changes at the maximum open position of the cam part 42 as a boundary (change point). Specifically, when the cam part 42 is located between the closed position and the maximum open position, the pressing force PF of the cam contact part 435 pressing the cam part 42 is converted into the rotational force RF of rotating the cam part 42 in the closing direction. When the cam part 42 is located between the maximum open position and the rotation stop position, the pressing force PF of the cam contact part 435 pressing the cam part 42 is converted into the rotational force RF of rotating the cam part 42 in the opening direction. Therefore, when the user turns the cam lever 41 from the rotation stop position in the closing direction, the cam lever 41 is turned against the rotational force RF, which acts on the cam part 42 to rotate the cam part 42 in the opening direction, until the cam lever 41 is turned from the rotation stop position to the maximum open position. When the user turns the cam lever 41 in the closing direction just beyond the maximum open position, the direction of the rotational force RF changes, and the pressing force PF is converted into the rotational force RF of rotating 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 turn the cam lever 41 in the closing direction. Therefore, the user can turn the cam lever 41 to the closed position in the closing direction with a small force.

As the cam lever 41 is turned in the closing direction beyond the maximum open position, the rotational force RF, which is caused to rotate the cam part 42 in the closing direction by the pressing force PF of the cam contact part 435 pressing the cam part 42, is increased. Therefore, once the user turns the cam lever 41 to a prescribed position beyond the maximum open position in the closing direction, then the cam lever 41 is turned to the closed position without the need for the user to apply a force thereto. In this case, the compression springs 45 needs to have a prescribed or larger spring constant.

As described above, the sander 10 of this embodiment has the cam lever 41 that can hold the clamping member 43 in the open position against the biasing forces of the compression springs 45, so that the clamping member 43 can be held in the open position. Therefore, the user's work of setting a sanding sheet onto the clamping mechanism 40 can be facilitated.

When the user of the sander 10 sets a sanding sheet onto the clamping member 43 held in the open position by the cam lever 41 and then operates the cam lever 41 to release holding of the clamping member 43 in the open position, the clamping 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 of operating the cam lever 41 in the closing direction. Therefore, the sanding sheet can be held by the clamping member 43 with user's simple operation and small force.

According to this embodiment, the clamping mechanisms 40 are respectively arranged on the front and rear sides across the center of the sanding part 30, so that the size increase of the sander 10 in the left-right direction can be suppressed.

According to this embodiment, as shown in FIG. 4, the clamping mechanism 40 on the rear part of the base 32 is arranged in a region under the dust collecting nozzle 72. The lever part 412 has a part having a height increasing upward in a direction away from the rotational axis of the cam part 42. A highest part (a part having the largest height in the up-down direction) of the lever part 412 is configured such that an uppermost end 413 (see FIG. 7) does not contact with the dust collecting nozzle 72 when the cam part 42 is rotated. Thus, the size increase of the whole sander 10 can be suppressed by effectively utilizing the region under the dust collecting nozzle 72 while allowing rotation of the cam part 42.

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

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

According to this embodiment, the cam lever 41 (the cam part 42) is used as the holding mechanism. Thus, a user of the sander 10 can hold the clamping member 43 in the open position against the biasing force of the compression spring 45 without using a large force.

According to this embodiment, the sander 10 has the stopper 324 that stops rotation of the cam part 42 in the opening direction in a position (rotation stop position) where the sliding width of the clamping member 43 toward the open position starts decreasing after being maximized in the maximum open position. Thus, the stopper 324 can hold the clamping member 43 widely slid to the open position, which makes it easy for the user to set a sanding sheet. Further, the cam lever 41 and the clamping member 43 can maintain the open state even if the user releases a hand from the cam lever 41.

Further, the rotational force RF of rotating the cam part 42 in the opening direction is applied to the cam part 42 in the rotation stop position, and the cam part 42 is stopped from rotating by the stopper 324. As a result, even if the user releases a hand from the cam lever 41 in the rotation stop position, the rotational force RF of rotating the cam part 42 in the opening direction is applied to the cam part 42 in the rotation stop position, so that the cam lever 41 and the clamping member 43 can maintain the open state. Further, since the rotational force RF of rotating the cam part 42 in the opening direction is applied to the cam part 42 in the rotation stop position, even if a smaller force than the rotational force RF of rotating the cam part 42 in the opening direction is externally applied to the cam lever 41, the cam lever 41 is not turned in the closing direction, so that the clamping mechanism 40 can maintain the open state. Therefore, by provision of this structure, the clamping mechanism 40 can stably maintain the open state.

In this embodiment, the length of the elastic element housing part 325 in the front-rear direction is shorter than the natural length of the compression spring 45. Thus, the compression spring 45 is housed in a compressed state in the elastic element housing part 325. Therefore, when assembling the clamping mechanism 40 in the manufacturing process of the sander 10, the compression spring 45 can be fixed within the clastic element housing part 325 without using an assembling jig. In the case of using a torsion spring in the clamping mechanism, however, an assembling jig is often required to assemble 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.

In this embodiment, the clamp upper surface part 431 is configured to cover the compression spring 45 housed in the elastic element housing part 325 on the upper side of the base 32. With this configuration, the compression spring 45 can be protected from external factors. Specifically, provision of the clamp upper surface part 431 avoids direct contact of the compression spring 45 with external tools, members, dust and liquid.

In the sander 10 of this embodiment, the outer contour of the lever part 412 in the closed position is located inward of the outer contour of the base 32, when viewed from the up-down direction. More specifically, the outer contour of the lever part 412 is located inward of the outer contour of the sheet placement surface 311 in the surface direction when the clamping member 43 is in the closed position. Thus, in sanding operation using the sander 10, contact of the outer contour of the lever part 412 with a workpiece or a part or wall rising upward from the workpiece is avoided. As a result, a user can perform sanding operation up to corners of the workpiece.

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.

The sander 10 is an example of the “sander”. The sanding paper is an example of the “sanding sheet”. The sheet placement surface 311 is an example of the “sheet placement surface”. The sanding part 30 is an example of the “sanding part”. The clamping mechanism 40 is an example of the “clamping mechanism”. The clamping mechanism 40 arranged frontward of the center of the sanding part 30 is an example of the “front clamping mechanism”. The clamping mechanism 40 arranged rearward of the center of the sanding part 30 is an example of the “rear clamping mechanism”. The clamping member 43 is an example of the “clamping part”. The compression spring 45 is an example of the “elastic element”. The compression spring 45 is an example of the “spring”. The handle 22 is an example of the “handle”. The cam lever 41 is an example of the “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 “stopper”. The elastic element housing part 325 is an example of the “housing part”. The fan 71 is an example of the “suction part”. The dust collecting nozzle 72 is an example of the “dust collecting nozzle”.

Other Embodiments

Representative, non-limiting examples of the present disclosure were described above in detail. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the disclosure. The present disclosure may be implemented by a diversity of configurations without departing from the scope of the disclosure. The technical features of the above embodiment that correspond to the technical features described above may be replaced or combined appropriately, in order to solve part or all of the problems described above or in order to achieve part or all of the advantageous effects described above. Any of the technical features may be omitted.

In the above-described embodiment, the compression spring 45 is employed 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. 16, an elongate rubber member 46 is disposed in the elastic element housing part 325. The rubber member 46 applies a biasing force of 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 turned toward the open position from the closed position as a starting point, as shown in FIG. 17, the rubber member 46 deforms within the elastic element housing part 325 and applies the biasing force to the clamping member 43. The rubber member 46 as the elastic element has the same function as the compression spring 45. With such a structure, the same effect as the above-described embodiment can be obtained. Further, the clamping mechanism 40 can be manufactured at lower cost than the above-described embodiment.

In another example, a tension spring may be employed as the elastic element. As shown in FIG. 18, an elongate tension spring 47 is disposed in the elastic element housing part 325. The tension spring 47 is arranged within the elastic element housing part 325, but in a different position from the above-described embodiment. In this embodiment, the tension spring 47 is arranged closer to the center of the base 3 than the spring contact part 433 within the elastic element housing part 325. With such arrangement, the tension spring 47 biases the clamping member 43 toward the closed position by tension (biasing force). The tension is applied in a direction parallel to the sheet placement surface 311. When the cam lever 41 is turned in the opening direction from the closed position as a starting point, as shown in FIG. 19, the tension spring 47 generates the tension by being extended within the elastic element housing part 325 and applies the biasing force to the clamping member 43. The tension spring 47 as the clastic element has the same function as the compression spring 45. Where the tension spring 47 is used as the clastic element, one end of the tension spring 47 needs to be fixed to the elastic element housing part 325, and the other end to the spring contact part 433.

In the above-described embodiment, a structure not having the pad 31 may be employed. In this case, the bottom surface of the base 32 serves as the “sheet placement surface”

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 on the rear part of the base 32, and have the other clamping mechanism different in structure from the clamping mechanism 40 of this embodiment on the front part 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 used.

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

In the above-described embodiment, the stopper 324 may be arranged in such a position as to stop rotation of the cam part 42 in the opening direction in the maximum open position. With such a structure, the stopper 324 can hold the clamping member 43 widely slid to the open position, which makes it easy for the user to set a sanding sheet. As an alternative structure, the stopper 324 may be arranged in such a position as to stop rotation of the cam part 42 in the opening direction in a prescribed position after the sliding width of the clamping member 43 toward the open position is maximized and starts decreasing, when cam part 42 (the cam lever 41) is rotated toward the open position. Specifically, in this sander, the holding mechanism may have the stopper that stops rotation of the cam part in the opening direction after the sliding width of the clamping part toward the open position is maximized and starts decreasing, where the rotating direction of the cam part to press the clamping part toward the open position is defined as the opening direction, and the rotating direction of the cam part to allow the clamping part to slide toward the closing position is defined as the closing direction. With such a structure, the cam lever 41 and the clamping member 43 can maintain the open state even if the user releases a hand from the cam lever 41. Further, the stopper 324 can hold the clamping member 43 widely slid to the open position, which makes it easy for the user to set a sanding sheet.

In the above-described embodiment, the clamping mechanism 40 may have only one clastic element. This structure can be provided by arranging the elastic element in the vicinity of a central part of the clamping mechanism 40 other than the cam part 42.

In the above-described embodiment, 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 clamping member 43 in the open position against the biasing force of the elastic element may be disposed in the cam housing part 323. When the clamping member 43 is moved to the open position, the rod-like member is located between the clamping member 43 (a part corresponding to the cam contact part 435) and a wall of the cam housing part 323 in abutment with these parts, and holds the clamping member 43 in the open position against the biasing force of the elastic element. This can simplify the structure.

The disclosure is not limited to any of the above-described embodiment and the other embodiments or modifications described above but may be implemented by a diversity of configurations without departing from the scope of the disclosure. For example, the technical features of any of the above embodiments and their modifications may be replaced or combined appropriately, in order to solve part or all of the problems described above or in order to achieve part or all of the advantageous effects described above. Any of the technical features may be omitted appropriately unless the technical feature is described as essential in the description hereof.

DESCRIPTION OF THE REFERENCE NUMERALS

• • 10: sander, 20: housing, 22: handle, 25: switch, 30: sanding part, 31: pad, 32: base, 40: clamping mechanism, 41: cam lever, 42: cam part, 43: clamping member, 45: compression spring, 46: rubber member, 47: tension spring, 50: battery mounting part, 52: controller, 55: battery, 60: driving mechanism, 61: electric motor, 62: bearing, 63: bearing, 64: bearing, 65: balancer, 66: driving shaft, 71: fan, 72: dust collecting nozzle, 73: foot, 80: grip, 82: dust bag, 100: grip mounting part, 311: sheet placement surface, 321: boss, 323: cam housing part, 324: stopper, 325: elastic element housing part, 327: side surface part, 328: groove, 412: lever part, 413: uppermost end, 414: through hole, 415: screw, 431: clamp upper surface part, 433: spring contact part, 435: cam contact part, 437: sheet contact part, 611: motor shaft, 612: motor body, 661: one end of the driving shaft, A1: driving axis, PF: pressing force, RF: rotational force

Claims

1. A sander, comprising: a sanding part having a planar sheet placement surface on which a sanding sheet can be set; andat least one clamping mechanism configured to hold the sanding sheet on the sanding part, wherein:the at least one clamping mechanism includes: a clamping part that is configured to hold the sanding sheet and to be slid in a direction parallel to the sheet placement surface between a closed position to hold the sanding sheet on a side surface of the sanding part and an open position to allow removal of the sanding sheet;at least one elastic element that applies a biasing force of biasing the clamping part toward the closed position, in a direction parallel to the sheet placement surface; anda holding mechanism that is configured to hold the clamping part in the open position against the biasing force, andthe clamping part is allowed to hold the sanding sheet when the holding mechanism is released from holding the clamping part in the open position.

2. The sander as defined in claim 1, further comprising an elongate handle, wherein:a direction orthogonal to the sheet placement surface defines an up-down direction of the sander,a direction in which the handle extends when viewed from the up-down direction defines a front-rear direction of the sander,the at least one clamping mechanism includes: a front clamping mechanism arranged frontward of a center of the sanding part; anda rear clamping mechanism arranged rearward of the center of the sanding part.

3. The sander as defined in claim 1, wherein: each of the at least one elastic element is an elongate spring, andthe elongate spring extends in a direction parallel to the sheet placement surface.

4. The sander as defined in claim 1, wherein each of the at least one elastic element is an elongate compression spring.

5. The sander as defined in claim 1, wherein the holding mechanism includes a cam part that abuts on the clamping part and presses the clamping part toward the open position by rotating in an opening direction.

6. The sander as defined in claim 5, wherein: the cam part allows the clamping part to slide to the closed position by rotating in a closing direction opposite to the opening direction, andthe holding mechanism includes a stopper that stops rotation of the cam part in the opening direction in a position where a sliding width of the clamping part toward the open position is maximized or starts decreasing after being maximized.

7. The sander as defined in claim 5, wherein: the holding mechanism further includes a lever part that is configured to be manipulated to rotate the cam part, andan outer contour of the lever part is located inward of an outer contour of the sheet placement surface in a surface direction when the clamping part is in the closed position.

8. The sander as defined in claim 5, further comprising: a suction part that sucks sanding dust generated from a workpiece by sanding with the sander; anda dust collecting nozzle that discharges the sucked sanding dust rearward in the sander,wherein:the at least one clamping mechanism includes a rear clamping mechanism arranged rearward of the center of the sanding part,the rear clamping mechanism is arranged in a region under the dust collecting nozzle,the holding mechanism further includes a lever part that is operated to rotate the cam part,the lever part has a part having a height increasing upward in a direction away from a rotational axis of the cam part, anda highest part of the lever part has such a height as to avoid contact with the dust collecting nozzle when the cam part is rotated.

9. The sander as defined in claim 4, wherein: the sanding part includes at least one housing part that houses the compression spring, andeach of the at least one housing part has a shorter length than a natural length of the compression spring in an extending direction of the compression spring.

10. The sander as defined in claim 9, wherein the clamping part is configured to cover an upper side of the compression spring housed in the at least one housing part.

11. The sander as defined in claim 4, wherein: the holding mechanism includes: a cam part that abuts on the clamping part and presses the clamping part toward the open position by rotating in an opening direction, anda lever part that is operated to rotate the cam part, andan outer contour of the lever part is located inward of an outer contour of the sheet placement surface in a surface direction when the clamping part is in the closed position.

12. The sander as defined in claim 4, comprising: a suction part that sucks sanding dust generated from a workpiece by sanding with the sander, anda dust collecting nozzle that discharges the sucked sanding dust rearward in the sander,wherein:the at least one clamping mechanism includes a rear clamping mechanism arranged rearward of the center of the sanding part,the rear clamping mechanism is arranged in a region under the dust collecting nozzle,the holding mechanism includes: a cam part that abuts on the clamping part and presses the clamping part toward the open position by rotating in an opening direction, anda lever part that is operated to rotate the cam part,the lever part has a part having a height increasing upward in a direction away from a rotational axis of the cam part, anda highest part of the lever part has such a height as to avoid contact with the dust collecting nozzle when the cam part is rotated.

13. The sander as defined in claim 1, wherein: the holding mechanism includes a cam part that abuts on the clamping part and presses the clamping part toward the open position by rotating in an opening direction,the clamping part includes: at least one spring contact part to which the biasing force is applied from the at least one elastic element,a cam contact part that abuts on the cam part and transmits a rotational force applied to the cam part to the clamping part, anda sheet contact part that holds the sanding sheet between the sheet contact part and the sanding part.

14. The sander as defined in claim 13, wherein: the sheet contact part has an end part that is bent toward a side surface part of the sanding part,the end part of the sheet contact part is located outward of an outer contour of the sheet placement surface in a surface direction, and in the closed position, presses the side surface part by the biasing force and clamps the sanding sheet between the end part of the sheet contact part and the side surface part.

15. The sander as defined in claim 14, wherein a groove is formed in the side surface part and configured to receive the end part of the sheet contact part in the closed position.