Dust collection system for power tool

Appropriate control is performed in accordance with the state of a power tool and/or a dust collection attachment. A dust collection system for a power tool includes a hammer drill to hold a bit, a dust collection attachment connected to the hammer drill, and a dust collection controller that controls the operation of the hammer drill and/or the dust collection attachment in accordance with the specifications of the hammer drill and/or the dust collection attachment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese Patent Application No. 2019-058950, filed on Mar. 26, 2019, the entire contents of which are hereby incorporated by reference.

BACKGROUND

1. Technical Field

The present invention relates to a dust collection system for a power tool.

2. Description of the Background

A power tool such as an electric drill or a hammer drill may be used in a dust collection system in which a dust collection attachment is attached to collect and store dust from a workpiece during machining such as drilling, as one such example is described in Japanese Unexamined Patent Application Publication No. 2018-69397. In such a known dust collection system, a dust collection fan included in the dust collection attachment is rotated by a dust collection motor to suck air including dust through a suction port at a tip of the tool. The air including dust then passes through a dust box inside the dust collection attachment, where it is caught by a filter inside the dust box and stored without scattering.

BRIEF SUMMARY

In a known dust collection system, a dust collection motor operates at a constant rotational speed independently of the operation of a bit, the capacity of a dust box, or the performance of a filter in a dust collection attachment. Some dust may remain uncollected during an operation producing a large amount of dust and may scatter. Also, the operator may continue using the system without noticing that the small-capacity dust box stores much dust. Also, the operator may operate the tool without a dust box or filter attached.

One or more aspects of the present invention are directed to a dust collection system that performs appropriate control in accordance with the state of a power tool and/or a dust collection attachment.

An aspect of the present invention provides a dust collection system for a power tool, the system including:

a power tool configured to hold a tip tool;

a dust collection attachment connected to the power tool; and

a system control unit configured to control an operation of the power tool and/or the dust collection attachment in accordance with a specification of the power tool and/or the dust collection attachment.

The dust collection system according to the above aspect of the present invention performs appropriate control in accordance with the state of the power tool and/or the dust collection attachment.

DETAILED DESCRIPTION

One or more embodiments will now be described with reference to the drawings.

FIG. 1is a longitudinal central sectional view of a dust collection system S including a hammer drill1(an example of a power tool) to which a dust collection attachment40is attached.

The hammer drill1includes a housing2and a motor (brushless motor)3. The housing2includes a pair of right and left halves of the housing that are assembled together. The motor3is accommodated in a front lower portion of the housing2to have an output shaft4tilted rearward. A countershaft6is supported in the front-rear direction above the motor3. The countershaft6receives a torque transmitted through a bevel gear5. The countershaft6receives a first gear7, a clutch8, and a boss sleeve9in this order from the front. Above the countershaft6, a tool holder10is axially supported in parallel with the countershaft6. The tool holder10can hold a bit B at its distal end. A piston cylinder11is inserted through the rear of the tool holder10in a movable manner. The piston cylinder11receives an arm13connected at its rear end. The boss sleeve9externally holds the arm13via a swash bearing12with the axis tilted. The piston cylinder11contains a striker15across an air chamber14in a reciprocable manner. The striker15can strike an impact bolt16located in front of the striker15. The first gear7meshes with a second gear17attached to the tool holder10.

A handle18is located in a rear upper portion of the housing2. The handle18includes a switch19and a switch lever20. A battery mount21is located below the handle18. The battery mount21receives two battery packs22aligned in the front-rear direction as a power supply. Each battery pack22is slide-attached in the lateral direction. The battery mount21internally includes terminal blocks23. The terminal blocks23are electrically connectable to the attached battery packs22. A controller24is accommodated above the terminal blocks23to extend in the front-rear direction. The controller24is electrically connected to electric components including the motor3, the switch19, and the terminal blocks23. The controller24includes a circuit board receiving, for example, a microcomputer and switching elements.

A wireless unit25is located on a right side surface of the housing2behind the countershaft6. The wireless unit25is electrically connected to the controller24. The wireless unit25can communicate, using a wireless communication technique such as Bluetooth (registered trademark), with an external dust collection device (not shown) that also has the wireless communication function.

The front lower portion of the housing2is an attachment portion30. The attachment portion30has a front surface sloping downward, and protrudes in front of the battery packs22. The attachment portion30receives the dust collection attachment40. A female connector31is located below the motor3inside the attachment portion30. The female connector31includes a female terminal for power supply and two female terminals for communication (three female terminals in total) arranged in the lateral direction. An insertion opening32is formed in the front surface of the attachment portion30in front of the female connector31. The female connector31is supported in a manner swingable about its rear end in the up-down direction. The female connector31is urged to the lowermost position by a torsion spring (not shown) to allow an upper shutter33to close the insertion opening32. A pressing bar34is located below the female connector31in a manner movable upward and downward. The pressing bar34protrudes toward the lower surface of the attachment portion30at the lowermost position of the female connector31. A lower recess35is located at the lateral center of the lower surface of the attachment portion30. The lower recess35is open frontward and downward. The pressing bar34protrudes in the lower recess35. The two side surfaces of the attachment portion30on the right and left of the lower recess35each have a guide groove (not shown) extending in the front-rear direction. The guide grooves receive the dust collection attachment40in a slidable manner.

The dust collection attachment40includes a pair of right and left halves of a casing that are assembled together. The dust collection attachment40includes a casing41. A rear upper portion of the casing41is fitted with the attachment portion30of the hammer drill1. A rear lower portion of the casing41accommodates a dust collection motor42. The dust collection motor42includes an output shaft43facing frontward. A dust collection controller44is located below the dust collection motor42. A dust collection fan45is fastened to the output shaft43. The dust collection fan45is accommodated in an air inlet chamber46. The air inlet chamber46is a compartment defined in the casing41, and has an air outlet (not shown) in its side surface. The casing41includes a connecting portion47at its front lower surface for a dust box70. The connecting portion47is in front of the air inlet chamber46and recedes to have a front opening. A partition48behind the connecting portion47serving as the bottom of the connecting portion47has a communication hole49. The communication hole49is coaxial with the dust collection fan45, and connects the connecting portion47and the air inlet chamber46. A light-emitting diode (LED)50for indication is located behind the dust collection controller44on a side surface of the casing41. The LED50is electrically connected to the dust collection controller44.

A male connector51is located on an upper rear surface of the casing41. The male connector51includes three plate-like male terminals for power supply and for communication in total. The male terminals protrude rearward.

Two button switches52A and52B are aligned vertically in front of the male connector51on the rear surface of the partition48. The button switches52A and52B each have a front surface as a pressing surface (operational surface), which is placed through a through-hole53in the partition48to be contained in the connecting portion47.

A pair of guide rails55(FIG. 2) are located on the right and left on a rear upper surface of the casing41. The guide rails55extend in the front-rear direction, and can be fitted in the guide grooves on the right and left surfaces of the attachment portion30. The rear upper surface of the casing41includes an upward pressing member56between the guide rails55. The upward pressing member56has a rear surface sloping downward. When the attachment portion30is fitted, the upward pressing member56enters the lower recess35and presses the pressing bar34upward.

In the casing41, a guide passage57extends above the connecting portion47in the front-rear direction. The guide passage57has an open front end, and a rear end bent in a U shape to extend behind the connecting portion47. The guide passage57holds a guide cylinder58protruding forward. A slide cylinder59is internally connected to the guide cylinder58in a manner movable in the front-rear direction. A nozzle60is connected to the front end of the slide cylinder59. The nozzle60is L-shaped and has a tip upward. The nozzle60has a cylindrical suction port61in its tip. A bit B coaxially passes through the suction port61.

The guide passage57and the slide cylinder59internally accommodate a flexible hose62. The flexible hose62has a front end connected to the nozzle60, and a rear end connected to a duct63. The duct63is a cylinder bent in a U shape in conformance with the rear end shape of the guide passage57. A spiral wire64is located integrally with the flexible hose62to urge the flexible hose62in an extension direction. The flexible hose62urges the nozzle60and the slide cylinder59forward. A lower end portion of the duct63passes through the partition48, and protrudes inside the connecting portion47. A receiving shaft65protrudes laterally at the lower end of the connecting portion47and in front of the partition48. An engagement protrusion66is located at a frontward position on an upper inner surface of the connecting portion47. The engagement protrusion66engages with an upper side of the dust box70.

The dust box70includes a box body71and a lid73. The box body71is a deep box having an opening rearward. The lid73is a vertically long rectangle, and is connected to a portion below the opening of the box body71with a hinge shaft72in a rotatable manner.

The lid73has an engagement tab74on its upper end. The engagement tab74is a loop that engages with the upper surface of the box body71in a closed state of the opening of the box body71and maintains the closed state. The lid73has a rectangular inlet75extending laterally on its upper end. The inlet75receives the lower end portion of the duct63when the lid73is attached to the connecting portion47. The lid73has a circular outlet76on its lower end. The outlet76faces the communication hole49when the lid73is attached to the connecting portion47.

A filter compartment77is located in front of the outlet76of the lid73. The filter compartment77holds a paper filter78folded laterally with vertical folds. In this state, the tops of the vertical folds of the filter78are exposed at equal intervals in the lateral direction. The right and left sides of the filter78are also exposed inside the box body71.

The lower surface of the box body71has a groove79to fit with the receiving shaft65for the connecting portion47. An operation tab80is located on the upper surface of the box body71to elastically engage with the engagement protrusion66on the connecting portion47. A dust removal knob81is located on a front lower surface of the box body71. The dust removal knob81is rotated to vibrate the box body71to remove accumulating dust off the filter78.

Protrusions82are located between the inlet75and the outlet76on the rear surface of the lid73. The protrusions82correspond to the button switches52A and52B on the partition48. The number of protrusions82differs depending on the specifications of the dust box70. The dust box70is attached to change the on/off states of the button switches52A and52B. A combination of the on/off states of the button switches52A and52B can be associated with each set of specifications of the dust box70. The dust collection controller44identifies each set of specifications of the dust box70based on the combination of the on/off states of the button switches52A and52B.

As shown inFIGS. 2A and 2B, a detection unit83, such as a Hall device, is located at an inner rear end of the guide cylinder58in the casing41. The detection unit83is electrically connected to the dust collection controller44. A magnet84is located at an outer rear end of the slide cylinder59. The magnet84faces the detection unit83when the slide cylinder59is at the rearmost position. The detection unit83detects a change in the magnetic field of the magnet84that moves in cooperation with the slide cylinder59moving back and forth. The dust collection controller44thus detects the position of the slide cylinder59in the front-rear direction, and determines the length of the bit B corresponding to the position in the front-rear direction.FIGS. 1 and 2Ashow the system for a long bit.FIGS. 2B and 3show the system for a normal bit.

The dust collection controller44performs preset control in accordance with the on/off states of the button switches52A and52B and the set of specifications identified by the detection unit83. Example sets of specifications to be identified and their associated control will be described below.

(1) The capacity of the dust box70is determined to change the setting for maintenance timing. The setting for maintenance timing may be a threshold to be compared with the cumulative operating time. For example, the threshold is set higher for the dust box70having a large capacity, and is set lower for the dust box70having a small capacity.

(2) The type (performance) of the filter78is determined to rotate the dust collection motor42at a higher rotational speed for a high-performance filter, or at a lower rotational speed for a low-performance filter. A high-performance filter may be a high-efficiency particulate air (HEPA) filter with high filtering efficiency, or may be a filter using a cloth filter and a paper filter in combination.

(3) The length of the bit B is determined to rotate the dust collection motor42at a higher rotational speed for a long bit, or at a lower rotational speed for a normal bit.

As shown inFIG. 4, the lid73facing rearward is placed to have an inclined posture with the groove79fitted with the receiving shaft65from the front. The lid73is then pressed into the connecting portion47to be raised upright with the operation tab80elastically engaged with the engagement protrusion66, thus allowing attachment to the connecting portion47. In the attached state, the duct63has its distal end fitted with the inlet75to protrude into the box body71. The outlet76thus faces the communication hole49and communicates with the air inlet chamber46. The dust collection attachment40defines an internal dust collection path R for sucking air through the suction port61and through the nozzle60, the flexible hose62, the duct63, and the filter78in the box body71to the air inlet chamber46.

In the dust collection system S according to the present embodiment, the dust collection attachment40is attached to the hammer drill1by first aligning the guide grooves on the attachment portion30with the guide rails55on the casing41to place the attachment portion30above the rear portion of the casing41. The dust collection attachment40is then slid rearward to fit the casing41with the attachment portion30from the front. Thus, the guide rails55are fitted into the right and left guide grooves on the attachment portion30for connecting the attachment portion30with the guide rails55. The upward pressing member56enters the lower recess35and presses the pressing bar34upward. This moves the shutter33upward to swing the female connector31to the uppermost position facing the insertion opening32. The dust collection attachment40thus allows the male terminals of the male connector51to enter the housing2through the insertion opening32. The male terminals are thus electrically connected to the female terminals of the female connector31.

The suction port61is placed to abut against a target surface of a workpiece, and the switch lever20is pressed. The switch19is turned on to cause the controller24to drive the motor3and rotate the countershaft6. A switching knob (not shown) on a side surface of the housing2is operated to slide the clutch8for selecting a drill mode, a hammer mode, or a hammer drill mode. In the drill mode, the clutch8is at a frontward position to mesh with the first gear7alone. In the hammer mode, the clutch8is at a rearward position to mesh with the boss sleeve9alone. In the hammer drill mode, the clutch8is at a middle position to mesh with the first gear7and the boss sleeve9at the same time.

In the drill mode, the tool holder10is rotated with the second gear17to rotate the bit B. In the hammer mode, the arm13swings to reciprocate the piston cylinder11. The striker15is operated through the air chamber14in cooperation with the piston cylinder11, and strikes the bit B with the impact bolt16. In the hammer drill mode, the tool holder10rotates and the impact bolt16is struck at the same time.

When the switch19is turned on, the controller24provides power to the dust collection controller44. The dust collection controller44then determines the on/off states of the button switches52A and52B, the capacity of the dust box70, and the type of the filter78. Also, the detection unit83detects the position of the slide cylinder59in the front-rear direction, and determines the length of the bit B. The dust collection controller44further starts counting the operating time for the dust collection attachment40, and determines the threshold for the cumulative operating time in accordance with the determined type of the filter78for maintenance timing indication.

When neither the button switches52A nor52B is turned on, the dust collection controller44transmits, to the controller24, information indicating that the dust box70has yet to be attached. The controller24then stops driving the motor3. The controller24does not drive the dust collection motor42. The LED50indicates an error.

With the suction port61positioned for operation, the hammer drill1is moved forward to move the nozzle60and the slide cylinder59rearward. The bit B thus passes through the suction port61and machines the workpiece. Once the machining starts, the dust collection controller44drives the dust collection motor42to rotate the dust collection fan45. The dust collection motor42is rotated at a predetermined rotational speed in accordance with the capacity of the dust box70, the type of the filter78, and the length of the bit B determined earlier. For example, the rotational speed is set higher when the dust box70has a large capacity or when the filter78has high filtering efficiency. Once the detection unit83determines that the bit B is a long bit, the dust collection controller44rotates the dust collection motor42at a higher rotational speed although the dust box70has a small capacity and the filter78has low filtering efficiency. When the filter78has high filtering efficiency, the threshold for the cumulative operating time is set higher.

The dust collection fan45rotates to suck the outside air through the suction port61, which then passes through the nozzle60, the dust collection path R, and the air inlet chamber46and is discharged outside through the air outlet. Thus, dust from the workpiece is sucked through the suction port61, enters the dust box70through the nozzle60, the flexible hose62, and the duct63, and passes through the filter compartment77and is caught by the filter78and stored in the box body71.

When the cumulative operating time of the dust box70reaches the threshold, the dust collection controller44provides a maintenance notification. The maintenance notification is provided by, for example, lighting the LED50or producing an electronic sound or a buzzer sound.

After the dust collection system S stops operating, the operator slides the dust collection attachment40forward to detach it from the hammer drill1with the procedure reverse to the attachment of the dust collection attachment40. In the dust collection attachment40, the operation tab80is pressed down and disengaged from the engagement protrusion66, and the dust box70is rotated about the receiving shaft65to have its upper portion pulled down forward, and is thus detached from the connecting portion47. The engagement tab74on the lid73is disengaged from the box body71to open the lid73, and dust can be discarded from the box body71through the opening of the box body71. To discard dust, the dust box70alone may be detached without detaching the dust collection attachment40from the hammer drill1. The filter78may be cleaned or changed as appropriate. The suction force is thus restored to allow use of the dust collection system S. The cumulative operating time is reset when the dust box70is detached.

In the dust collection system S according to the present embodiment, the dust collection controller44(system control unit) controls the operation of the hammer drill1that can hold the bit B (tip tool) and/or the dust collection attachment40in accordance with the specifications of the hammer drill1and/or the dust collection attachment40. The system thus performs appropriate control in accordance with the state of the hammer drill1and/or the dust collection attachment40.

In particular, the dust collection controller44allows timely maintenance in accordance with the capacity of the dust box70, thus allows timely maintenance including dust removal or disposal.

The dust collection controller44controls the rotational speed of the dust collection motor42in accordance with the performance of the filter78. For the filter78with high performance (e.g., high filtering efficiency), the dust collection controller44increases the rotational speed of the dust collection motor42to increase the dust collection efficiency.

The dust collection controller44identifies the specifications by detecting the number of protrusions82on the dust box70. This simple structure including the button switches52A and52B and the protrusions82allows reliable identification of multiple sets of specifications.

The dust collection controller44does not drive the dust collection motor42when the dust box70has yet to be attached. This prevents an operation without collecting dust, and thus prevents scattering dust.

The dust collection controller44controls the rotational speed of the dust collection motor42in accordance with the specifications of the bit B, or specifically, the type (length) of the bit B. This allows dust collection in accordance with the amount of dust generated.

The specifications to be identified by the dust collection controller44may not be limited to those described in the above embodiment, and may include the specifications of a dust box70A including the box body71with no dust removal knob as shown inFIG. 5, or the specifications of a dust box70B including the lid73with no filter or no outlet to the dust collection fan and connectable to a hose86from an external dust collection device with a joint85as shown inFIG. 6.

As shown inFIGS. 1 and 5, the dust removal knob is detectable. Once the dust removal knob is detected, early indication may be generated to prompt dust removal and delay the timing for maintenance of the filter78. Any dust removal mechanisms other than the dust removal knob may be used.

In the system shown inFIG. 6, the wireless unit25may allow cooperation with a dust collection device to collect dust. This structure may drive the motor3alone without driving the dust collection motor42, and thus prevent unintended operation of the dust collection motor42. This structure may eliminate the filter.

Further, the specifications of the tip tool to be identified may include the diameter of the gimlet bit, in addition to the length of the bit.

When various sets of specifications are to be identified as described above, more button switches may be located on the casing or more protrusions may be located on the dust box, or the protrusions may have different heights to allow different pressing depths to be detected for the button switches. The protrusions may not be located on the dust box, but may be located on the filter to allow determination on whether the filter is attached.

Instead of the determination mechanism including the button switches and the protrusions, as shown inFIG. 6, the partition48may include a reader/writer unit90electrically connectable to the dust collection controller44on its rear surface, and the lid73may include an information storage91, such as an IC tag, on its rear surface in front of the reader/writer unit90. This contactless determination mechanism can obtain information about more sets of specifications than a mechanism using button switches.

To control the system, the controller for the hammer drill alone may be used instead of the dust collection controller, or both the controllers may be used.

In some embodiments, the hammer drill may include a motor oriented differently or a motor of a different type or battery packs arranged differently as appropriate. The hammer drill may be powered by alternating current (AC) and may include a power cord, instead of battery packs. The dust collection attachment may also have any structure for connection to the hammer drill, any arrangement of the dust box, and any structure for connection of the dust box other than those described in the above embodiment.

The present invention is applicable not only to a hammer drill but also to other power tools to which a dust collection attachment, such as an electric drill and an electric hammer, is connected.

REFERENCE SIGNS LIST