U.S. patent application number 13/235733 was filed with the patent office on 2012-03-29 for dust collector.
This patent application is currently assigned to MAKITA CORPORATION. Invention is credited to Goshi ISHIKAWA, Kazuhiko YOSHIDA.
Application Number | 20120073077 13/235733 |
Document ID | / |
Family ID | 44719499 |
Filed Date | 2012-03-29 |
United States Patent
Application |
20120073077 |
Kind Code |
A1 |
ISHIKAWA; Goshi ; et
al. |
March 29, 2012 |
DUST COLLECTOR
Abstract
A dust collector for suctioning dust includes: an electric motor
for collecting dust; a power supply device that supplies electric
power to outside; a parameter detection device that detects a
parameter (hereinafter referred to as a "current parameter") which
changes depending on a state of a supplied current supplied by the
power supply device; a determination device that determines whether
or not a value of the current parameter detected by the parameter
detection device satisfies a condition based on a threshold value
stored in a first storage unit; and a current supply starting
device that starts current supply to the electric motor when it is
determined by the determination device that the value of the
current parameter satisfies the condition.
Inventors: |
ISHIKAWA; Goshi; (Anjo-shi,
JP) ; YOSHIDA; Kazuhiko; (Anjo-shi, JP) |
Assignee: |
MAKITA CORPORATION
Anjo-shi
JP
|
Family ID: |
44719499 |
Appl. No.: |
13/235733 |
Filed: |
September 19, 2011 |
Current U.S.
Class: |
15/347 |
Current CPC
Class: |
A47L 9/2805 20130101;
A47L 9/2857 20130101; B23D 59/006 20130101; A47L 7/0095 20130101;
G01R 19/16571 20130101; A47L 9/2842 20130101; A47L 9/2868
20130101 |
Class at
Publication: |
15/347 |
International
Class: |
A47L 9/00 20060101
A47L009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 27, 2010 |
JP |
2010-215823 |
Claims
1. A dust collector for suctioning dust comprising: an electric
motor for collecting dust; a power supply device that supplies
electric power to outside; a parameter detection device that
detects a parameter (hereinafter referred to as a "current
parameter") which changes depending on a state of a supplied
current supplied by the power supply device; a determination device
that determines whether or not a value of the current parameter
detected by the parameter detection device satisfies a condition
based on a threshold value stored in a first storage unit; and a
current supply starting device that starts current supply to the
electric motor when it is determined by the determination device
that the value of the current parameter satisfies the
condition.
2. The dust collector according to claim 1, wherein the parameter
detection device detects an integrated current value, which is
obtained by integrating an absolute value of a current value of the
supplied current from when supply of the supplied current is
started, as the current parameter.
3. The dust collector according to claim 2, wherein the first
storage unit stores a first threshold value indicating a threshold
value of the integrated current value, and the determination device
determines that the value of the current parameter satisfies the
condition when the value of the current parameter is equal to or
more than the first threshold value.
4. The dust collector according to claim 3, wherein the parameter
detection device resets the current parameter to an initial value
when an integrated time, which is obtained by integrating a time
during which the current value of the supplied current is less than
a second threshold value stored in a second, storage unit, exceeds
a third threshold value stored in a third storage unit.
5. The dust collector according to claim 1, wherein the power
supply device supplies electric power having a periodically
changing current value, and when a time, during which the absolute
value of the current value of the supplied current is more than "0"
and also is equal to or more than a predetermined current value
that is less than a maximum current value, is referred to as a
"current supply time", the parameter detection device detects, as
the current parameter, an integrated value of the current supply
time from when supply of the supplied current is started.
6. The dust collector according to claim 5, wherein the first
storage unit stores a fourth threshold value indicating a threshold
value of the integrated value of the current supply time, and the
determination device determines that the value of the current
parameter satisfies the condition when the value of the current
parameter is equal to or more than the fourth threshold value.
7. The dust collector according to claim 1, wherein the power
supply device supplies electric power having a periodically
changing current value, and when a state, in which an absolute
value of the current value of the supplied current is more than "0"
and also is equal to or more than a predetermined current value
that is less than a maximum current value, is referred to as a
"current supplied state", a time during which the current supplied
state is present is referred to as a "current supply time", and a
number of times of shifts to the current supplied state from when
supply of the supplied current is started is referred to as a
"counter value", the parameter detection device detects the counter
value as the current parameter, while making the counter value
correspond to the current supply time.
8. The dust collector according to claim 7, wherein the first
storage unit stores a fifth threshold value indicating a threshold
value of the counter value corresponding to the current supply
time, the fifth threshold value being set to be larger as the
current supply time is shorter, and the determination device
determines that the value of the current parameter satisfies the
condition when the value of the current parameter is equal to or
more than the fifth threshold value.
9. The dust collector according to claim 5, wherein the parameter
detection device resets the current parameter to an initial value
when an integrated time, which is obtained by integrating a time
during which the current supply time is unable to be detected,
exceeds a sixth threshold value stored in the first storage
unit.
10. The dust collector according to claim 1, further comprising a
condition changing device that is configured to change a value
indicating the condition and is operable by a user.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Japanese Patent
Application No. 2010-215823 filed Sep. 27, 2010 in the Japan Patent
Office, the disclosure of which is incorporated herein by
reference.
BACKGROUND
[0002] The present invention relates to a dust collector which can
be activated interlocking with activation of an electric power tool
or the like.
[0003] For example, in an interlocking system of a dust collector
disclosed in Patent Document 1, a transmission unit that detects
activation of an electric power tool and transmits a wireless
signal indicating a detection of activation is provided to the
electric power tool. The dust collector (a dust collector motor) is
automatically activated when the dust collector receives the
wireless signal.
Patent Document 1: Japanese Unexamined Patent Application
Publication No. 2008-36723
SUMMARY
[0004] However, according to experiments and studies by the
inventors of the present invention, an activation timing of the
dust collector is sometimes inappropriate relative to an activation
timing of the electric power tool in the aforementioned
interlocking system. It is desirable to achieve an appropriate
activation timing of a dust collector relative to an activation
timing of an electric power tool.
[0005] In a first aspect of the present invention, there is
provided a dust collector for suctioning dust which includes an
electric motor (5) for collecting dust, a power supply device (7),
a parameter detection device (13), a determination device (13), and
a current supply starting device (13). The power supply device (7)
supplies electric power to outside. The parameter detection device
(13) detects a parameter (hereinafter referred to as a "current
parameter") which changes depending on a state of a supplied
current supplied by the power supply device (7). The determination
device (13) determines whether or not a value of the current
parameter detected by the parameter detection device (13) satisfies
a condition based on a threshold value stored in a first storage
unit (ROM). The current supply starting device (13) starts current
supply to the electric motor (5) when it is determined by the
determination device (13) that the value of the current parameter
satisfies the condition. According to the first aspect of the
invention, an activation timing of the dust collector may be
controlled to an appropriate timing.
[0006] In a second aspect of the present invention, the parameter
detection device (13) detects an integrated current value, which is
obtained by integrating an absolute value of a current value of the
supplied current from when supply of the supplied current is
started, as the current parameter.
[0007] In a third aspect of the present invention, the first
storage unit (ROM) stores a first threshold value indicating a
threshold value of the integrated current value, and the
determination device (13) determines that the value of the current
parameter satisfies the condition when the value of the current
parameter is equal to or more than the first threshold value.
[0008] In a fourth aspect of the present invention, the parameter
detection device (13) resets the current parameter to an initial
value when an integrated time, which is obtained by integrating a
time during which the current value of the supplied current is less
than a second threshold value stored in a second storage unit
(ROM), exceeds a third threshold value stored in a third storage
unit (ROM).
[0009] In a fifth aspect of the present invention, the power supply
device (7) supplies electric power having a periodically changing
current value, and when a time, during which the absolute value of
the current value of the supplied current is more than "0" and also
is equal to or more than a predetermined current value (i.sub.0)
that is less than a maximum current value, is referred to as a
"current supply time" (T.sub.2), the parameter detection device
(13) detects, as the current parameter, an integrated value of the
current supply time (T.sub.2) from when supply of the supplied
current is started.
[0010] In a sixth aspect of the present invention, the first
storage unit (ROM) stores a fourth threshold value indicating a
threshold value of the integrated value of the current supply time
(T.sub.2 ), and the determination device (13) determines that the
value of the current parameter satisfies the condition when the
value of the current parameter is equal to or more than the fourth
threshold value.
[0011] In a seventh aspect of the present invention, the power
supply device (7) supplies electric power having a periodically
changing current value, and when a state, in which the absolute
value of the current value of the supplied current is more than "0"
and also is equal to or more than a predetermined current value
(i.sub.0) that is less than a maximum current value, is referred to
as a "current supplied state", a time during which the current
supplied state is present is referred to as a "current supply time"
(T.sub.2), and a number of times of shifts to the current supplied
state from when supply of the supplied current is started is
referred to as a "counter value", the parameter detection device
(13) detects the counter value as the current parameter, while
making the current value correspond to the current supply time
(T.sub.2).
[0012] In an eighth aspect of the present invention, the first
storage unit (ROM) stores a fifth threshold value indicating a
threshold value of the counter value corresponding to the current
supply time (T.sub.2) the fifth threshold value being set to be
larger as the current supply time (T.sub.2) is shorter, and the
determination device (13) determines that the value of the current
parameter satisfies the condition when the value of the current
parameter is equal to or more than the fifth threshold value.
[0013] In a ninth aspect of the present invention, the parameter
detection device (13) resets the current parameter to an initial
value when an integrated time, which is obtained by integrating a
time during which the current supply time is unable to be detected,
exceeds a sixth threshold value stored in a sixth storage unit
(ROM).
[0014] In a tenth aspect of the present invention, there is
provided a condition changing device (27A, 27B) that is configured
to change a value indicating the condition and is operable by a
user.
[0015] Each of assigned reference letters and numerals in the above
description is intended to indicate an example of a correspondence
between each device in the present invention and a component in
later-described embodiments. The each device in the present
invention is not limited to the component represented by the
reference letter or numeral in the embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The present invention will now be described by way of
example with reference to the accompanying drawings, in which:
[0017] FIG. 1 is a front elevational view of a dust collector in
preferred embodiments of the present invention;
[0018] FIG. 2 is a view showing a connection state between the dust
collector and an electric power tool in the preferred embodiments
of the present invention;
[0019] FIG. 3 is a block diagram showing a controller of the dust
collector in a first embodiment of the present invention;
[0020] FIG. 4 is a flowchart illustrating an operation of the
controller of the dust collector in the first embodiment of the
present invention;
[0021] FIG. 5 is a graph showing a current value of a current
flowing in an outlet and an integrated value of the current
value;
[0022] FIG. 6 is a graph showing a current value of a current
flowing in an outlet and an integrated value of the current
value;
[0023] FIG. 7 is a view for illustrating a definition of a current
supply time T.sub.2;
[0024] FIG. 8 is a block diagram showing a controller of a dust
collector in a second embodiment of the present invention;
[0025] FIG. 9A shows an example of a current waveform outputted
from a current detection unit;
[0026] FIG. 9B is a chart showing an example of Case (a) in the
present specification;
[0027] FIG. 9C is a chart showing an example of Case (b) in the
present specification;
[0028] FIG. 9D is a chart showing an example of Case (c) in the
present specification;
[0029] FIG. 10A is a flowchart showing an operation of the
controller of the dust collector in the second embodiment of the
present invention;
[0030] FIG. 10B is a flowchart showing the operation of the
controller of the dust collector in the second embodiment of the
present invention;
[0031] FIG. 11A is a block diagram showing a controller of a dust
collector in a third embodiment of the present invention; and
[0032] FIG. 11B is a block diagram showing a controller of a dust
collector in the third embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] A dust collector 1 according to an embodiment of the present
invention will be described hereinafter with reference to the
drawings. The dust collector 1 may be, for example, a dust
collector which can be activated interlocking with activation of an
electric power tool, such as an electric circular saw (a
disk-shaped saw). In the present embodiment, when the dust
collector 1 is activated interlocking with activation of the
electric power tool, dust such as sawdust can be rapidly suctioned
by the dust collector 1 before the dust is scattered around.
First Embodiment
1. Schematic Configuration of Dust Collector
1.1. Appearance of Dust Collector
[0034] As shown in FIG. 1, an activation switch 3 of the dust
collector 1, a suction power adjustment dial 4 (hereinafter simply
referred to as "the adjustment dial 4") for adjusting suction
power, an electric outlet 7 for supplying electric power to
outside, etc. are provided in a front upper portion of the dust
collector 1.
[0035] In the dust collector 1 of the present embodiment, an
electric motor 5 for collecting dust (see FIG. 3) is activated when
the activation switch 3 is turned to an "ON" state, while the
electric motor 5 is stopped when the activation switch 3 is turned
to an "OFF" state. When the activation switch 3 is turned to an
"Interlock" state, an operation mode of the dust collector 1 is
turned to an interlock mode. The interlock mode is a mode in which
the electric motor 5 is activated and stopped interlocking with
activation and stop of an electric power tool 50 (see FIG. 2)
connected to the electric outlet 7.
[0036] In the dust collector 1 of the present embodiment, as shown
in FIG. 2, an extension cord 11 is integrated into a flexible hose
9 for suction. When a power plug 51 of the electric power tool 50
is inserted into an electric outlet 11A of the extension cord 11,
and a plug 11B of the extension cord 11 is inserted into the
electric outlet (see FIG. 1), the electric power tool 50 can be
indirectly connected to the electric outlet 7.
1.2. Controller of Dust Collector
[0037] As shown in FIG. 3, a controller 2 of the dust collector 1
includes a CPU module 13, a current detection unit 15, a dust
collector motor control unit 17 (hereinafter simply referred to as
"the motor control unit 17"), a zero-cross detection unit 19, a
control circuit power source 21 (hereinafter simply referred to as
"the power source 21"), an activation switch 3, and the adjustment
dial 4. The controller 2 controls operations of the electric motor
5 and the like.
[0038] The CPU module 13 is an integrated combination of a CPU
(Central Processing Unit), a ROM, a RAM, and an A/D converter. The
CPU performs device control according to a program stored in the
ROM. The ROM is a memory for storing programs to be executed by the
CPU. The RAM is a memory for temporarily storing calculation
results and the like. The A/D converter converts analog signals
inputted to the CPU module 13 into digital signals.
[0039] The current detection unit 15 detects an absolute value of a
current value (hereinafter referred to as a "current absolute
value") of a supplied current (alternating current in the present
embodiment) which is supplied through the electric outlet 7. Then,
in synchronization with starting of supply of the supplied current,
the current detection unit 15 inputs an analog signal indicating
the detected current absolute value to the A/D converter in the CPU
module 13.
[0040] The motor control unit 17 controls operation of the electric
motor (electric motor for the dust collector) 5. Specifically, the
motor control unit 17 adjusts an electric power supplied from a
commercial power source (an AC power source) to an electric power
(a voltage) corresponding to a suction power set by the adjustment
dial 4, and supplies the adjusted electric power to the electric
motor 5. The operation of the motor control unit 17 is controlled
by the CPU module 13.
[0041] The zero-cross detection unit 19 detects a timing when a
voltage of the electric power supplied from the commercial power
source becomes 0 volt. The CPU module 13 controls the motor control
unit 17 such that power supply to the electric motor 5 is started
at the timing when the voltage of the electric power supplied from
the commercial power source becomes 0 volt.
[0042] The power source 21 is a power source circuit that supplies
electric power to drive control circuits such as the CPU module 13.
The power source 21 converts the electric power supplied from the
commercial power source into a direct current with a predetermined
voltage, and supplies the electric power (direct current power) to
the CPU module 13 and the like.
[0043] A main switch 23 is a manual switch that opens and closes a
circuit of the electric power supplied from the commercial power
source through a power plug 1A (see FIG. 2) of the dust collector
1. The main switch 23 is included in the activation switch 3 shown
in FIG. 1.
[0044] When the activation switch 3 is in the "Interlock" or "ON"
state, the main switch 23 is closed, and power supply to the power
source 21, to the control circuits such as the CPU module 13, and
to the electric outlet 7 is started, as well as power supply to the
electric motor 5 becomes available.
2. Operation of Dust Collector In Present Embodiment
2.1. Outline of Operation
[0045] When the main switch 23 is closed and power supply is
started, the CPU module 13 is activated, and a state of the
activation switch 3 is detected. When the activation switch 3 is in
the "ON" state, current supply to the electric motor 5 is
started.
[0046] When the activation switch 3 is in the "Interlock" state, a
program for performing interlocking control shown in FIG. 4 is read
from the ROM and is executed by the CPU, In other words, the
operation mode of the dust collector 1 is shifted to the interlock
mode. When the activation switch 3 is turned from the "Interlock"
state or the "ON" state to the "OFF" state, the main switch 23 is
opened. Thereby, power supply to the CPU module 13 is stopped, and
operation of the CPU module 13 is stopped.
[0047] Control steps (S1-S19) shown in FIG. 4 are performed at
predetermined respective time intervals according to a timer (not
shown) provided in the CPU module 13. Accordingly, an accumulated
number of performed control steps is increased in proportion to an
elapsed time from when the interlock mode is activated.
2.2. Interlock Mode (see FIG. 4)
[0048] Hereinafter, a "time counter value" is a value indicating a
level of an elapsed time. The elapsed time is a time that has
elapsed from when the time counter value is set to an initial value
(0). In the present embodiment, the elapsed time becomes longer in
proportion to an increase of the time counter value.
[0049] An integrated current value is a value obtained by
integrating an absolute value of a current value of a supplied
current from when current supply through the electric outlet 7 is
started. In the present embodiment, however, the integrated current
value is calculated by integrating only current values equal to or
more than a later-described lower limit value I.sub.0, in order to
exclude a noise current or the like flowing through the electric
power tool 50. In the present embodiment, the lower limit value Io
is a value that is smaller than a current value of a current which
is supplied during normal operation of the electric power tool 50
and can be regarded as a current value of a noise current or the
like.
[0050] When the interlock mode is activated, an initial value of
the time counter value ("0" in the present embodiment) and an
initial value of the integrated current value ("0" in the present
embodiment) are stored in the RAM (S1). Then, a digital signal
indicating a current value detected by the current detection unit
15, i.e., a signal converted by the AM converter, is read (S2).
[0051] Subsequently, it is determined whether or not a current is
supplied through the electric outlet 7 based on the signal read in
S2 (33). That is, it is determined whether or not a current has
been detected by the current detection unit 15. When it is
determined that a current has been detected (S3: YES), it is
determined whether or not the detected current value is equal to or
more than a threshold value (hereinafter, the threshold value is
referred to as the "lower limit value I.sub.0") previously stored
in the ROM (S5).
[0052] When it is determined that the detected current value is
equal to or more than the lower limit value I.sub.0 (S5: YES), the
time counter value stored in the RAM is reset to the initial value
(S7). Subsequently, the current value detected in S2, S3 is added
to the integrated current value stored in the RAM, and thereby the
integrated current value is updated (S9).
[0053] When the integrated current value is updated (S9), it is
determined whether or not the updated integrated current value is
equal to or more than a predetermined threshold value (hereinafter
referred to as the "integrated threshold value a") previously
stored in the ROM (811). When it is determined that the current
value is less than the integrated threshold value .sigma. (S11:
NO), the step S2 is performed again. On the other hand, when it is
determined that the current value is equal to or more than the
integrated threshold value .sigma. (S11: YES), current supply to
the electric motor 5 is started (S13). Subsequently, it is
determined whether or not the electric power tool 50 has stopped
based on the current value detected by the current detection unit
15.
[0054] When it is determined that the electric power tool 50 has
stopped (S15: YES), current supply to the electric motor 5 is
stopped (S16). Then, the step S1 is performed again. On the other
hand, when it is determined that the electric power tool 50 has not
stopped (S15: NO), current supply to the electric motor 5 is
continued.
[0055] When it is determined in S3 that a current is not detected
(S3: NO) or when it is determined in S5 that the detected current
value is less than the lower limit value I.sub.0 (S5: NO), "1" is
added to the time counter value stored in the RAM and thereby the
time counter value is updated (S17).
[0056] Subsequently, it is determined whether or not the updated
time counter value is equal to or more than a threshold value
(hereinafter the threshold value is referred to as the "time
threshold value T.sub.1") previously stored in the ROM (S19). When
it is determined that the time counter value is equal to or more
than the time threshold value T.sub.1 (S19: YES) the step S1 is
performed. On the other hand, when it is determined that the time
counter value is less than the time threshold value T.sub.1 (S19:
NO), the step S2 is performed.
[0057] If power supply to the CPU module 13 is stopped during the
interlock mode by, for example, the main switch 23 being opened,
the integrated current value and the time counter value stored in
the RAM are cleared at the point of time since the RAM is a
volatile memory.
3. Features of Dust Collector of the Present Embodiment
[0058] The present embodiment has a feature that current supply to
the electric motor 5 is started when it is determined that a value
of a parameter (hereinafter referred to as a "current parameter"),
which changes depending on a state of a supplied current supplied
through the electric outlet 7, satisfies a predetermined
condition.
[0059] In the present embodiment, the integrated current value,
which is obtained by integrating the absolute value of the current
value of the supplied current from when current supply is started,
is treated as a current parameter. When the current parameter (the
integrated current value) is equal to or more than the integrated
threshold value .sigma., current supply to the electric motor 5 is
started (see FIG. 5).
[0060] In this case, the larger an increase rate of the current
parameter is, the earlier the current parameter reaches the
integrated threshold value .sigma. (see FIG. 5). In general, it is
desirable in an electric power tool having a higher increase rate
of the current parameter, i.e., an electric power tool in which a
larger current flows, that the dust collector 1 is activated
rapidly interlocking with an activation timing of the electric
power tool.
[0061] In the dust collector 1 of the present embodiment, when an
electric power tool in which a larger current flows is connected to
the electric outlet 7, the current parameter reaches the integrated
threshold value .sigma. early, and an activation timing of the dust
collector 1 becomes early. In other words, the activation timing of
the dust collector 1 can be controlled, to an appropriate
timing.
[0062] As seen from FIG. 5, a current (an inrush current) flowing
in the electric power tool 50 at a moment (in a transition period)
when power supply to the electric power tool 50 from the electric
outlet 7 is started is larger. FIG. 6 shows an example of a noise
current flowing in the electric power tool 50. Also in case of the
noise current, a current value in a transition period is larger
than a current value in a steady state (a steady-state current
value). Therefore, if it is configured such that current supply to
the electric motor 5 is started when a current value of a current
flowing in. the electric power tool 50 becomes equal to or more
than a predetermined value, the noise current may cause malfunction
of the dust collector 1.
[0063] However, a steady-state current value of a noise current is
smaller than a steady-state current value during use of an electric
power tool. It is, therefore, advantageous that the integrated
current value is treated as the current parameter. Specifically, a
configuration such that current supply to the electric motor 5 is
started when the integrated current value becomes equal to or more
than the integrated threshold value n enables activation of the
electric motor 5 rapidly interlocking with the activation timing of
the electric power tool, while eliminating influence of the noise
current (that is, avoiding erroneous starting of current supply to
the electric motor 5 by the noise current), as compared with a
configuration such that current supply to the electric motor 5 is
started when the current value becomes equal to or more than a
predetermined value.
[0064] In the steady state after the transition period terminates,
the steady-state current value of the noise current is less than
the lower limit value I.sub.0, and thus the current value of the
noise current is not integrated.
[0065] On the other hand, the current value in the transition
period (the current value of the inrush current) is large even in
the case of the noise current, and thus the current value of the
noise current is integrated, in the transition period.
[0066] In the event that the current value of the noise current is
additionally integrated to the integrated current value of the
noise current, an appropriate determination on the current supply
timing to the electric motor 5 cannot be made.
[0067] In contrast, according to the present embodiment, when the
current value of the supplied current is less than the lower limit
value I.sub.0 and also the elapsed time from when supply of the
supplied current is started becomes equal to or more than the time
threshold value T.sub.1, the current parameter (the integrated
current value) is reset to the initial value. In this case, it can
be avoided that the current value of the noise current additionally
integrated to the integrated current value of the noise current,
and thereby the integrated current value of the noise current
becomes equal to or more than the integrated threshold value
.sigma.. Thus, determination on the current supply timing to the
electric motor 5 can be appropriately made according to the present
embodiment.
4. Correspondence Between Invention Specifying Matters And Present
Embodiment
[0068] In the present embodiment, the electric outlet 7 corresponds
to an example of a power supply device, and the controller which is
constituted by the CPU module 13, the current detection unit 15,
and the like corresponds to an example of a parameter detection
device, an example of a determination device and an example of a
current supply starting device.
Second Embodiment
1. Outline of Dust Collector In Present Embodiment
[0069] In the first embodiment, the integrated current value
obtained by integrating the current value is used as the current
parameter, In a second embodiment, whether or not to start current
supply to the electric motor 5 is determined based on a product of
a current supply time T.sub.2 and a number of times of shifts to
the current supplied state, that is, a value equivalent to an
integrated value of the current supply time T.sub.2 from when
supply of the supplied current is started.
[0070] Here, the current supplied state means a state in which the
absolute value of the current value of the supplied current is
larger than "0" and also is equal to or more than a predetermined
current value i.sub.0, as shown in FIG. 7. The current value
i.sub.0 is smaller than a maximum current value. Also, the current
value i.sub.0 is larger than a value of a current which may be
regarded as a noise current. The current supply time T.sub.2 means
a time during which a current supplied state is present. In other
words, the current supply time T.sub.2 is a time during which the
absolute value of the current value of the supplied current is
equal to or more than the current value i.sub.0. Hereinafter, the
number of times of shifts to the current supplied state is referred
to as the "counter value". The number of times (the counter value)
is counted from the moment when supply of the supplied current is
started.
[0071] In the second embodiment, a current value which is identical
with the lower limit value I.sub.0 in the first embodiment is
adopted as a value of the current value i.sub.0. Hereinafter, the
current value i.sub.0 is indicated as a lower limit value
i.sub.0.
[0072] A frequency of the alternating current supplied through the
electric outlet 7 is identical with a frequency of the commercial
power source (the AC power source) regardless of the electric
device, such as the electric power tool 50, connected to the
electric outlet 7. If a voltage supplied through the electric
outlet 7 and an electric load generated in the electric power tool
50 or the like, which is connected to the electric outlet 7, are
constant, the current supply time T.sub.2 can be constant. For
example, during a very short time period at the time of activation
of the electric power tool 50, the current supply time T.sub.2 can
have a value specific to each electric power tool 50 (a constant
value). The larger the power consumption of the electric power tool
50 is, that is, the larger the current flowing to electric power
tool 50 is, the longer the current supply time T.sub.2 can be.
[0073] The product of the current supply time T.sub.2 and the
counter value can be a parameter characteristic of increasing in
conjunction with an increase of the integrated current value.
However, as described above, the current supply time T.sub.2 can
have the value specific to each electric power tool 50 (the
constant value) at the time of activation of the electric power
tool 50. Therefore, in the second embodiment, the counter value is
used as the current parameter. A plurality of threshold values to
be compared with the current parameter (the counter value) are
previously stored in accordance with a length of the current supply
time T.sub.2 (in, other words, in accordance with a largeness of
the current flowing in the electric power tool 50). In the second
embodiment, the current parameter (the counter value) is compared
with the threshold value corresponding to the current parameter,
and thereby a determination is made on whether or not to start
current supply to the electric motor 5.
[0074] The product of the current supply time T.sub.2 and the
counter value is identical with an integrated value of the current
supply time T.sub.2 from when supply of the supplied current is
started.
[0075] "Using the counter value as the current parameter" is equal
to "using the integrated value of the current supply time T.sub.2
from when supply of the supplied current is started as the current
parameter" in terms of the technical meaning.
2. Details of Dust Collector In Present Embodiment
2.1. Controller (see FIG. 8)
[0076] The current detection unit 15 of a controller 2A in the
second embodiment detects only a positive current out of supplied
currents which are supplied through the electric outlet 7, and
outputs the detected current to a comparator 25.
[0077] The comparator 25 compares the current value of the inputted
current and the lower limited value i.sub.0, and outputs a signal
to the CPU module 13 only while the current value of the inputted
current is equal to or more than the lower limited value i.sub.0,
that is, only in the current supplied state. Accordingly, a time
during which the comparator 25 outputs the signal is the current
supply time T.sub.2.
[0078] Among constituent devices of the controller, the same
devices as in the first embodiment are assigned the same reference
numerals as in the first embodiment, and thus no explanation
thereof will be provided here.
2.2. Operation of Dust Collector In Present Embodiment
[0079] Overall operation of the dust controller 1 in the second
embodiment is the same as the operation of the dust controller 1 in
the first embodiment, and differences lie only in terms of the
interlock mode. Therefore, the interlock mode will be described
hereinafter.
Outline of Interlock Mode
[0080] In the interlock mode in the second embodiment, current
supply to the electric motor 5 is started when the integrated value
of the current supply time T.sub.2 from when supply of the supplied
current is started, that is, the product of the current supply time
T.sub.2 and the counter value becomes equal to or more than a value
.sigma.' which corresponds to the integrated threshold value
.sigma. in the first embodiment.
[0081] In the first embodiment, the larger the increase rate of the
integrated current value is, the shorter time is required for the
integrated current value to reach the integrated threshold value
.sigma., and thus the earlier the activation timing of the dust
collector I becomes, as described above.
[0082] In the second embodiment, as described above, the number of
times of shifts to the current supplied state (the counter value)
is used as the current parameter, and current supply to the
electric motor 5 is started when the current parameter becomes
equal to or more than the threshold value which corresponds to the
length of the current supply time T.sub.2 and is previously stored
in the ROM.
[0083] Here, "using the number of times of shifts to the current
supplied state (the counter value) as the current parameter" is
equal to "using the product of the current supply time T.sub.2 and
the counter value (in other words, an integrated value of the
current supply time T.sub.2) as the current parameter" in terms of
the technical meaning. Also, the length of the current supply time
T.sub.2 means the greatness of the current value of the current
supplied to the electric power tool 50. According to the second
embodiment, therefore, the same operation and advantages can be
obtained as in the case of using the integrated current value as
the current parameter.
[0084] In the second embodiment, current supply to the electric
motor 5 is started in either Case (a) or (b) as follows:
(a) When the current supply time T.sub.2 is equal to or more than a
first current supply time T.sub.3, and the counter value
corresponding to the current supply time T.sub.2 becomes equal to
or more than a first integrated threshold value .sigma..sub.1. (b)
When the current supply time T.sub.2 is equal to or more than a
second current supply time T.sub.4, which is shorter than the first
current supply time T.sub.4, and the counter value corresponding to
the current supply time T.sub.2 becomes equal to or more than a
second threshold value .sigma..sub.2 which is greater than the
first threshold value .sigma..sub.1.
[0085] In a case excluding Cases (a) and (b) (for example, in Case
(c) below), current supply to the electric motor 5 is not
performed.
(c) When the current supply time T.sub.2 is less than the second
current supply time T.sub.4.
[0086] FIG. 9A shows an example of a current waveform outputted
from the current detection unit 15, FIG. 9B is a chart showing an
example of Case (a) above, FIG. 9C is a chart showing an example of
Case (b) above, and FIG. 9D is a chart showing an example of Case
(c) above.
Details of Interlock Mode
[0087] When the interlock mode is activated, as shown in FIG. 10,
initial values (both are "0" in the present embodiment) of a first
counter value C.sub.1 and a second counter value C.sub.2 as well as
initial values (both are "0" in the present embodiment) of a first
reset counter value C.sub.3 and a second reset counter value
C.sub.4 for determining timings to reset the first counter value
C.sub.1 and the second counter value C.sub.2 to the initial values
are stored in the RAM (S30).
[0088] Here, the first counter value C.sub.1 means a counter value
counted corresponding to the current supply time T.sub.2 when the
current supply time T.sub.2 is equal to or more than the first
current supply time T.sub.3 previously stored in the ROM. The
second counter value C.sub.2 means a counter value counted
corresponding to the current supply time T.sub.2 when the current
supply time T.sub.2 is equal to or more than the second current
supply time T.sub.4 previously stored in the ROM.
[0089] Subsequently, it is determined whether or not a current
value equal to or more than the lower limit value i.sub.0 has been
detected, that is, it is determined whether or not a signal has
been outputted from the comparator 25 (S31). When it is determined
that a current value equal to or more than the lower limit value
i.sub.0 has been detected (S31: YES), it is then determined whether
or not the current supply time T.sub.2 is equal to or more than the
first current supply time T.sub.3 (S33).
[0090] When it is determined that the current supply time T.sub.2
is equal to or more than the first current supply time T.sub.3
(S33: YES), "1" is added to each of the first counter value C.sub.1
and the second counter value C.sub.2 stored in the RAM, and thereby
the first counter value C.sub.1 and the second counter value
C.sub.2 are updated (S35). Also, the first reset counter value
C.sub.3 and the second reset counter value C.sub.4 are reset to the
respective initial values (S37).
[0091] Next, it is determined whether or not the first counter
value C.sub.1 is equal to or more than the first threshold value 01
previously stored in the ROM (S39). When it is determined that the
first counter value C.sub.1 is equal to or more than the first
threshold value .sigma..sub.1 (S39: YES), current supply to the
electric motor 5 is started (S41).
[0092] Subsequently, it is determined whether or not the electric
power tool 50 has been stopped based on the current value detected
by the current detection unit 15 (S43). When it is determined that
the electric power tool 50 has been stopped (S43: YES), current
supply to the electric motor 5 is stopped (S44). Then, the step S30
is performed again. On the other hand, when it is determined that
the electric power tool 50 has not been stopped (S43: NO), current
supply to the electric motor 5 is continued.
[0093] When it is determined in S39 that the first counter value
C.sub.1 is not equal to or more than the first threshold value
.sigma..sub.1 (S39: NO), it is then determined whether or not the
second counter value C.sub.2 is equal to or more than the second
threshold value .sigma..sub.2 previously stored in the ROM (S55).
When it is determined that the second counter value C.sub.2 is
equal to or more than the second threshold value .sigma..sub.2
(S55: YES), current supply to the electric motor 5 is started
(S41). On the other hand, when it is determined that the second
counter value C.sub.2 is not equal to or more than the second
threshold value .sigma..sub.2 (S55: NO), the step S31 is performed
again.
[0094] When it is determined in S33 that the current supply time
T.sub.2 is less than the first current supply time T.sub.3 (S33:
NO), it is then determined whether or not the current supply time
T.sub.2 is equal to or more than the second current supply time
T.sub.4 (S45).
[0095] When it is determined that the current supply time T.sub.2
is equal to or more than the second current supply time T.sub.4
(S45: YES), "1" is added to the second counter value C.sub.2 stored
in the RAM and thereby the second counter value C.sub.2 is updated
(S47). Then, "1" is added to the first reset counter value C.sub.3
and thereby the first reset counter value C.sub.3 is updated, and
the second reset counter value C.sub.4 is reset to the initial
value (S49).
[0096] Subsequently, it is determined whether or not the first
reset counter value C.sub.3 is equal to or more than a first reset
threshold value C.sub.5 previously stored in the ROM (S51). When it
is determined that the first reset counter value C.sub.3 is less
than the first reset threshold value C.sub.5 (S51: NO), the step
S55 is performed.
[0097] On the other hand, when it is determined that the first
reset counter value C.sub.3 is equal to or more than the first
reset threshold value C.sub.5 (S51: YES), it means that a state, in
which the current supply time T.sub.2 is less than the first
current supply time T.sub.3, has been continued for a predetermined
time period or longer. Therefore, the first counter value C.sub.1
and the first reset counter value C.sub.3 are reset to the
respective initial values (S53).
[0098] That is, in the second embodiment, the step S31 is performed
at a zero-cross timing of the supplied current in synchronization
with a frequency of the supplied current supplied from the electric
outlet 7, except when the electric motor 5 is activated. Therefore,
when the first reset counter value C.sub.3 is equal to or more than
the first reset threshold value C.sub.5, the state, in which the
current supply time T.sub.2 is less than the first current supply
time T.sub.3, has been continued for a time period that is
determined by a product of the frequency of the supplied current
and the first reset threshold value C.sub.5.
[0099] Accordingly, in the second embodiment, when the first reset
counter value C.sub.3 is equal to or more than the first reset
threshold value C.sub.5, it is regarded that an electric power
tool, which requires such a large current that the current supply
time T.sub.2 is equal to or more than the first current supply time
T.sub.3, is not connected to the electric outlet 7 at least
currently (when the step S53 is performed). Thus, the first counter
value C.sub.1, which is a current parameter to make a determination
on the activation of the electric power tool requiring a large
current, is reset to the initial value.
[0100] Also, when it is determined in S31 that a current value
equal to or more than the lower limit value i.sub.0 is not detected
(S31: NO), or when it is determined in S45 that the current supply
time T.sub.2 is less than the second current supply time T.sub.4
(S45: NO), "1" is added to each of the first reset counter value
C.sub.3 and the second reset counter value C.sub.4, and thereby the
first reset counter value C.sub.3 and the second reset counter
value C.sub.4 are respectively updated (S57).
[0101] Subsequently, it is determined whether or not the first
reset counter value C.sub.3 is equal to or more than the first
reset threshold value C.sub.5 (S59). When it is determined that the
first reset counter value C.sub.3 is equal to or more than the
first reset threshold value C.sub.5 (S59: YES), the first counter
value C.sub.1 and the first reset counter value C.sub.3 are reset
to the respective initial values (S61) for the same reason as in
S53, and then the step S63 is performed.
[0102] On the other hand, when it is determined that the first
reset counter value C.sub.3 is less than the first reset threshold
value C.sub.5 (S59: NO), it is then determined whether or not the
second reset counter value C.sub.4 is equal to or more than a
second reset threshold value C.sub.6 previously stored in the ROM
(S63).
[0103] When it is determined that the second reset counter value
C.sub.4 is equal to or more than the second reset threshold value
C.sub.6 (S63: YES), the second counter value C.sub.2 and the second
reset counter value C.sub.4 are reset to the respective initial
values (S65). Then, the step S31 is performed again. On the other
hand, when it is determined that the second reset counter value
C.sub.4 is less than the second reset threshold value C.sub.6 (S63:
NO), the second counter value C.sub.2 or the like is not reset and
the step S31 is performed again.
[0104] The reason for resetting the second counter value C.sub.2
and the second reset counter value C.sub.4 to the respective
initial values when the second reset counter value C.sub.4 is equal
to or more than the second reset threshold value C.sub.6 is as
follows: It can be regarded that an electric power tool, which
requires such a large current that the current supply time T.sub.2
is equal to or more than the second current supply time T.sub.4, is
not connected to the electric outlet 7 currently (when the step S63
is performed) in a same manner as in S53.
3. Features of Dust Collector of Present Embodiment
[0105] The case where the first counter value C.sub.1 is equal to
or more than the first threshold value .sigma..sub.1, or the case
where the second counter value C.sub.2 is equal to or more than the
second threshold value .sigma..sub.2 means the same as the case
where the integrated value of the current supply time T.sub.2, from
when supply of the supplied current is started (that is, when the
current value equal to or more than the lower limit value i.sub.0
is detected in S31), becomes equal to or more than a predetermined
threshold value. Accordingly, the configuration of the second
embodiment may also be referred to as a configuration in which
current supply to the electric motor 5 is started when the current
parameter becomes equal to or more than a predetermined threshold
value. The current parameter is the integrated value of the current
supply time T.sub.2 from when supply of the supplied current is
started.
[0106] As aforementioned, the product of the current supply time
T.sub.2 and the first counter value C.sub.1, or the product of the
current supply time T.sub.2 and the second counter value C.sub.2 is
a parameter which, is characteristic of becoming greater in
conjunction with an increase of the integrated current value. The
longer the current supply time T.sub.2 is, the greater an increase
rate of the current integrated value becomes.
[0107] When it is configured such that the threshold value
corresponding to the number of times of shifts to the current
supplied state becomes larger as a value of the current supply time
T.sub.2 is smaller, as in the second embodiment, the dust collector
1 is activated more rapidly interlocking with the activation timing
of an electric power tool as a larger current flows in the electric
power tool. Thus, the activation timing of the dust collector 1 may
be controlled to an appropriate timing.
[0108] Also, in the second embodiment, when a state in which the
current supply time T.sub.2 is less than the first current supply
time T.sub.3 has been continued for a time period defined by the
first reset threshold value C.sub.5, the first counter value
C.sub.1 is reset to the initial value. When a state in which the
current supply time T.sub.2 is less than the second current supply
time T.sub.4 has been continued for a time period defined by the
second reset threshold value C.sub.6, the second counter value
C.sub.2 is reset to the initial value.
[0109] As such, in the second embodiment, when an integrated time
during which the current supply time T.sub.2 cannot be detected has
reached a predetermined time, the first counter value C.sub.1 or
the second counter value C.sub.2 as the current parameter is reset
to the initial value. Therefore, an unnecessary counter value (the
current parameter) is not considered when determining the current
supply timing to the electric motor 5, and thus an appropriate
determination on the current supply timing to the electric motor 5
can be made.
4. Correspondence Between Invention Specifying Matters and Present
Embodiment
[0110] In the second embodiment, the electric outlet 7 corresponds
to an example of a power supply device, and the controller which is
constituted by the CPU module 13, the current detection unit 15,
the comparator 25, and the like corresponds to an example of a
parameter detection device, an example of a determination device
and an example of a current supply starting device.
Third Embodiment
[0111] While the threshold values (the integrated threshold value
.sigma., the first threshold value .sigma..sub.1, and the second
threshold value .sigma..sub.2) to determine whether or not to start
current supply to the electric motor 5 are fixed values stored in
the ROM in the first and second embodiments, the threshold values
are configured to be variable by a user's operation in a third
embodiment.
[0112] Specifically, as shown in FIG. 11A and FIG. 11B, the dust
collector 1 includes a condition changing device, such as an
interlock sensitivity changeover switch 27A (hereinafter simply
referred to as the "changeover switch 27A") or an interlock
sensitivity changeover dial 27B (hereinafter simply referred to as
the "changeover dial 27B"), to change the threshold values.
[0113] The changeover switch 27A is a switch for stepwisely
changing a time from when the electric power tool is activated
until when the electric motor 5 is activated (hereinafter referred
to as the "interlock sensitivity"). The interlock sensitivity
changeover dial 27B is a switch for continuously changing the
interlock sensitivity. According to the third embodiment, the
activation timing of the dust collector 1 may be further
appropriately controlled.
[0114] In the first and second embodiments, the threshold values
cannot be directly changed since the threshold values are stored in
the ROM. Therefore, in the third embodiment, a value obtained by
multiplying each of the threshold value stored in the ROM by a
parameter is used as a threshold value to determine whether or not
to start current supply to the electric motor 5, and the interlock
sensitivity is changed by changing the parameter using the
changeover switch 27A or the like.
[0115] FIG. 11A shows an example in which the third embodiment is
applied to the controller in the first embodiment. FIG. 11B shows
an example in which the third embodiment is applied to the
controller in the second embodiment.
Other Embodiments
[0116] While an alternating current which periodically changes its
current value and current direction is supplied through the
electric outlet 7 in the above-described embodiments, the present
invention is not limited to such configuration, but may be applied
to a case where a direct current which periodically changes its
current value is supplied. Especially in the first embodiment, a
direct current with a constant current value may be used.
[0117] Also, while the current waveform inputted to the comparator
25 is a waveform obtained by half-wave rectification of the current
supplied through the electric outlet 7 in the second embodiment,
the present invention is not limited to such configuration, and a
full-wave, rectified waveform may be employed.
[0118] Further, while the threshold value is indirectly changed in
the third embodiment, the present invention is not limited to such
configuration, For example, the threshold value may be stored in a
rewritable non-volatile storage device and be directly changed by
the condition changing device, such as the changeover switch
27A.
[0119] Moreover, while the integrated current value or the like is
used as the parameter (the current parameter) which changes
depending on the state of supplied current supplied through the
electric outlet 7 in the above-described embodiments, the present
invention is not limited to such configuration.
[0120] While the integrated current value as the current parameter
is detected (calculated) by the CPU module 13 in the first
embodiment, the present invention is not limited to such
configuration. For example, the integrated current value may be
calculated using hardware such as an integration circuit.
[0121] In the second embodiment, the integrated value of the
current supply time T.sub.2 as the current parameter, that is, the
first counter value C.sub.1 or the like is detected (calculated) by
the CPU module 13, the comparator 25, or the like, the present
invention is not limited to such configuration. For example, the
current parameter may be detected using hardware constituted by a
combination of an integration circuit and a comparator or the
like.
[0122] While current supply to the electric motor 5 is stopped when
a supplied current from the electric outlet 7 becomes unable to be
detected, in the above-described embodiments, the present invention
is not limited to such configuration. For example, current supply
to the electric motor 5 may be stopped when a predetermined time
has elapsed after the supplied current from the electric outlet 7
becomes unable to be detected. This enables the electric motor 5 to
be stopped after dust in the flexible hose 9 is suctioned.
[0123] Also, the present invention should not be limited to the
above-described embodiments, but may be practiced in various forms
within the gist of the present invention.
* * * * *