U.S. patent application number 12/357300 was filed with the patent office on 2009-10-01 for tool operated switch for vacuums.
Invention is credited to Michael Loveless, Spencer Loveless, Kent Walker Mabey, Todd Palmer.
Application Number | 20090241283 12/357300 |
Document ID | / |
Family ID | 41114939 |
Filed Date | 2009-10-01 |
United States Patent
Application |
20090241283 |
Kind Code |
A1 |
Loveless; Michael ; et
al. |
October 1, 2009 |
TOOL OPERATED SWITCH FOR VACUUMS
Abstract
A vacuum control system allows the vacuum to be turned on and
off automatically based on the operation of an associated power
tool. The vacuum is able to run at full power without sacrificing
power to the power tool itself. Additionally, a pneumatic power
tool may be used to control the operation of the vacuum.
Inventors: |
Loveless; Michael; (Price,
UT) ; Loveless; Spencer; (Price, UT) ; Palmer;
Todd; (Salt Lake City, UT) ; Mabey; Kent Walker;
(West Jordan, UT) |
Correspondence
Address: |
BATEMAN IP LAW GROUP
P.O. BOX 1319
SALT LAKE CITY
UT
84110
US
|
Family ID: |
41114939 |
Appl. No.: |
12/357300 |
Filed: |
January 21, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61022506 |
Jan 21, 2008 |
|
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Current U.S.
Class: |
15/319 |
Current CPC
Class: |
A47L 9/2894 20130101;
A47L 9/2821 20130101; A47L 9/2831 20130101; A47L 7/0085 20130101;
A47L 7/0095 20130101 |
Class at
Publication: |
15/319 |
International
Class: |
A47L 5/00 20060101
A47L005/00 |
Claims
1. A vacuum comprising: a portable vacuum having a motor and a
power cord; a socket for providing power to a power tool other than
the vacuum; a sensor for sensing the operation of the power tool;
and a control module for receiving a signal from the sensor and for
selective providing a signal to the relay to thereby switch the
motor on and off.
2. The vacuum of claim 1, wherein the control module is configured
for switching the motor on when the power tool is turned on, for
leaving the motor on if the power tool is turned off after a period
of time less than a specified period of time, and for switching the
motor off if the power tool is turned off after operating for more
than the specified period of time.
3. The vacuum of claim 2, wherein the control module is configured
for switching off the motor when the power tool is turned off if
the motor was on before the power tool was switched on.
4. The vacuum of claim 1, further comprising a port for receiving a
signal from a remote switch to thereby control the operation of the
motor.
5. A system comprising the vacuum of claim 1, wherein the vacuum
comprises first communications means for communicating remotely
with a remote switch; and wherein the system further comprises a
remote switch separate from the vacuum, the remote switch
comprising: a connection which is connectable to a source of power
for a power tool; a connection which is connectable to a power tool
to thereby provide power to the power tool; a sensor for sensing
when the power tool is operating; and second communications means
for communicating with the vacuum such that the operation of the
power tool controls the operation of the vacuum motor.
6. The system of claim 5, wherein the first communications means
comprises an electrical connector, and wherein the second
communications means comprises a cable for connection to the
electrical connector.
7. The system of claim 5, wherein the first communications means
comprises a wireless receiver, and wherein the second
communications means comprises a wireless transmitter for
communication with the wireless receiver.
8. The system of claim 5, wherein the connection which is
connectable to a source of power is a power cord.
9. The system of claim 5, wherein the connection which is
connectable to a source of power is an air hose.
10. A vacuum system for use with a power tool comprising: a vacuum,
the vacuum comprising a vacuum motor and a hose for connecting the
vacuum to a power tool; a control module for controlling the
operation of the vacuum motor; and a signal receiving device for
communicating with a remote switch; a remote switch separate from
the vacuum comprising: a connector which is connectable to a source
of power suitable for powering a power tool; a connector which is
connectable to a power tool so as to provide said source of power
to the power tool to thereby operate the power tool; a sensor for
sensing the operation of the power tool; and a signal transmitting
device for communicating with the control module; and wherein the
control module operates the vacuum motor according to the operation
of the power tool.
11. The system of claim 10, wherein the control module operates the
vacuum motor to turn the vacuum motor on when the power tool is
turned on and to turn the vacuum motor off when the power tool is
turned off.
12. The system of claim 10, wherein the control module operates the
vacuum motor to turn the vacuum motor on when the power tool is
turned on, keep the vacuum motor on when the power tool is turned
off if the power tool was operated for less than a predetermined
period of time; and turn the vacuum motor off when the power tool
is turned off if the power tool was operated for more than a
predetermined period of time.
13. The system of claim 12, wherein the control module further
operates the vacuum motor to turn the motor off when the power tool
is turned off if the vacuum motor was turned on before the power
tool was turned on.
14. The system of claim 10, wherein the signal receiving device
comprises an electrical socket and the signal transmitting device
comprises an electrical cable.
15. The system of claim 10, wherein the signal receiving device
comprises a wireless receiver and the signal transmitting device
comprises a wireless transmitter.
16. A method for controlling a vacuum comprising: selecting a
vacuum having a vacuum motor and a hose; selecting a control module
for receiving a signal indicating the operation of a power tool and
for controlling the operation of the vacuum motor in accordance to
the operation of the power tool; selecting a power tool; using the
vacuum in concert with the power tool to perform a task; and
operating the vacuum so that the vacuum is turned on and off
according to the operation of the power tool.
17. The method of claim 16, wherein the method comprises selecting
a remote switch separate from the vacuum, the remote switch
comprising a connector connectable to a power source for the power
tool, a connector connectable to the power tool to thereby power
the tool, and a signal transmitting device for transmitting a
signal to the control module; connecting the vacuum to an
electrical outlet; connecting the remote switch to a power source
separate from the electrical outlet; connecting the power tool to
the remote switch; the remote switch sensing the operation of the
power tool; and the remote switch transmitting a signal to the
control module to indicate the operation of the power tool; and the
control module operating the vacuum motor according to the
operation of the power tool.
18. The method of claim 17, wherein the power tool is electric, and
wherein the remote switch is connected to an electrical outlet
which is different than the outlet to which the vacuum is connected
to thereby power the power tool.
19. The method of claim 17, wherein the power tool is pneumatic,
and wherein the remote switch is connected to a source of
compressed gas.
20. The method of claim 16, wherein the step of operating the
vacuum comprises, more specifically, the control module operating
the vacuum motor to turn the vacuum motor on when the power tool is
turned on, keep the vacuum motor on when the power tool is turned
off if the power tool was operated for less than a predetermined
period of time; and turn the vacuum motor off when the power tool
is turned off if the power tool was operated for more than a
predetermined period of time.
21. The method of claim 20, wherein the control module operates the
vacuum motor to turn the vacuum motor off when the power tool is
turned off if the vacuum motor was on before the power tool was
turned on.
Description
1. RELATED APPLICATIONS
[0001] The present application claims the benefit of U.S.
Provisional Application Ser. No. 61/022506, filed Jan. 21, 2008,
which is expressly incorporated herein by reference in its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. The Field of the Invention
[0003] The present invention relates to a switch for controlling a
vacuum. More specifically, the present invention relates to a
switch for turning a vacuum on and off by sensing operation of a
tool which is used in combination with the vacuum.
[0004] 2. State of the Art
[0005] Due to health concerns and a desire to reduce the mess of
dust and debris, vacuums (typically canister vacuums as shown
herein) and dust collection shrouds or guards are becoming
increasingly common. These dust collection systems are used in many
situations such as concrete grinding or paint removal to capture
the debris which is generated. The debris is, in many cases,
hazardous to the health. Where hazardous debris such as concrete
dust or paint dust is generated, it is even more important to
capture the dust and debris.
[0006] There are many situations where a worker is not using the
desired tool for a long period of time, but is using the tool
intermittently. In these situations, it is desirable to turn off
the vacuum when the tool is not in use so as to conserve energy and
reduce the noise level. It is, however, inconvenient to switch the
vacuum on and off manually.
[0007] As shown in FIG. 1, vacuums 10 have been made which provide
power to an electric tool and which operate the vacuum when the
tool is operated. The vacuum 10 includes a power cord 14 which is
plugged into a wall outlet to provide power to the vacuum and to an
additional tool. The vacuum includes a socket 18 which receives the
power cord of the desired tool, such as a drill or grinder. The
socket 18 is electrically connected to the power cord 14 so as to
provide power to the tool. The vacuum 10 includes an internal
controller which powers the vacuum motor when the tool is powered.
The vacuum 10 turns on when the tool is turned on and turns off
when the tool is turned off. The vacuum 10 also has a typical
on/off switch 22 so that the vacuum can be placed in a permanent on
position.
[0008] FIG. 2 shows a schematic diagram of the vacuum electrical
components for the vacuum of FIG. 1. The vacuum power cord 14 is
connected to a controller 26 and switch 22 and thereby provides
power to both the vacuum motor 30 and the socket 18. The socket 18
always receives power when the power cord 14 is plugged into a
power source so that a desired power tool can be operated. When the
power tool is being operated, the controller 26 provides power to
the vacuum motor 30. The controller 26 provides surplus power which
is not being used by the power tool to the vacuum motor 30 so as to
not overload the electrical outlet that the power cord 14 is
plugged into. In this manner, the vacuum will run when the
associated power tool is being operated and turn off when the power
tool is turned off. The switch 22 allows the vacuum to be turned
permanently on, disabling the socket 18 at the same time.
[0009] The prior art vacuum of FIG. 1 has several drawbacks. One
drawback is that the vacuum 10 can only operate automatically when
used with an electrical tool and not other tools such as a
pneumatic tool. Another drawback is that the worker must switch the
vacuum 10 on and off at the vacuum itself to have the vacuum run
continuously, such as when cleaning up stray debris after
performing some work with a power tool. The vacuum 10 may be
located away from the worker and this may cause additional
inconvenience and difficulty.
[0010] Another drawback of the vacuum 10 is that the power tool and
the vacuum both share a common power supply. The power cord 14
provides power to both the vacuum and the power tool. Most wall
outlets will provide a maximum of 15 amps of current, less a 20%
safety margin, resulting in a 12 amp allowable load. Many vacuums
are designed to draw nearly 12 amps so as to maximize the suction
generated by the vacuum. Power tools, however, commonly draw 7-12
amps. Many angle grinders as may be used with the vacuum 10 will
draw a full 12 amps. Because of the high power draw of the tools
commonly used with the vacuum, the vacuum motor 30 is often only
allowed to draw 3 amps or less so as to not overload the electrical
circuit powering the vacuum 10 and the power tool. The vacuum 10
will provide very little air flow and little suction when operating
at 3 amps or less. Thus, the vacuum 10 is not operating at full
power when used with a power tool and will not adequately collect
the dust and debris due to the reduced air flow and suction.
[0011] There is a need for a tool operated vacuum which overcomes
the limitations of the prior art. There is a need for a vacuum
which is automatically switched on and off when a power tool is
switched on and off which still operates under full power even when
the power tool is operating. There is a need for a vacuum which can
be remotely switched on and off for continuous operation. There is
also a need for a vacuum which can be remotely switched by an air
powered tool.
SUMMARY OF THE INVENTION
[0012] It is an object of the present invention to provide an
improved vacuum control system which operates a vacuum based on the
operation of an associated power tool.
[0013] According to one aspect of the invention, the vacuum draws
full power even when an associated power tool is being operated.
The vacuum will thus always generate full suction and air flow and
will properly collect the dust and debris.
[0014] According to another aspect of the invention, the vacuum may
be switched into and out of a continuously operating state
remotely.
[0015] According to another aspect of the invention, the vacuum may
be switched on and off by an air tool and not just an electrically
operated tool.
[0016] These and other aspects of the present invention are
realized in a vacuum control system as shown and described in the
following figures and related description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Various embodiments of the present invention are shown and
described in reference to the numbered drawings wherein:
[0018] FIG. 1 shows a perspective view of a prior art vacuum.
[0019] FIG. 2 shows a schematic diagram of the electrical system of
the vacuum of FIG. 1;
[0020] FIG. 3 shows a perspective view of a vacuum and control
system according to the present invention;
[0021] FIG. 4 shows another perspective view of a vacuum and
control system according to the present invention;
[0022] FIG. 5 shows a schematic diagram of the vacuum control
system of the present invention;
[0023] FIG. 6 shows an electrical diagram of the vacuum control
system of the present invention;
[0024] FIG. 7 shows another electrical diagram of the vacuum
control system of the present invention; and
[0025] FIG. 8 shows another electrical diagram of the vacuum
control system of the present invention.
[0026] It will be appreciated that the drawings are illustrative
and not limiting of the scope of the invention which is defined by
the appended claims. The embodiments shown accomplish various
aspects and objects of the invention. It is appreciated that it is
not possible to clearly show each element and aspect of the
invention in a single figure, and as such, multiple figures are
presented to separately illustrate the various details of the
invention in greater clarity. Similarly, not every embodiment need
accomplish all advantages of the present invention.
DETAILED DESCRIPTION
[0027] The invention and accompanying drawings will now be
discussed in reference to the numerals provided therein so as to
enable one skilled in the art to practice the present invention.
The drawings and descriptions are exemplary of various aspects of
the invention and are not intended to narrow the scope of the
appended claims.
[0028] Turning now to FIG. 3, a perspective view of a vacuum and
control system of the present invention is shown. The vacuum 50
includes a power cord 54 which provides power to the vacuum motor
and to a power socket 58. A power tool may be plugged into the
socket 58 and the power tool may be used to control the vacuum 50.
A switch 62 is provided to allow the vacuum to be switched on and
off in a conventional manner, overriding the tool start
features.
[0029] The vacuum 50 also includes a port 66 which may be connected
to a remote switch 70 via a control cable 74. Additionally, a
wireless receiver 66b could be provided for communication with the
remote switch 70. The connector 78 on the control cable 74 plugs
into the port 66. The remote switch 70 includes a power cable 82
and includes a socket 86 into which a power tool may be plugged.
The remote switch 70 includes a sensor which detects when a power
tool connected to the socket 86 is on and which sends a signal to
the vacuum 50 via the control cable 74 and port 66 to switch the
vacuum on. The sensor could be a current sensor, a voltage sensor,
etc. The remote switch 70 may additionally include a wireless
transmitter 66a.
[0030] FIG. 4 shows an alternate embodiment of the vacuum control
system of FIG. 3 where the remote switch 70 is configured for
operation with a pneumatic tool, such as a die grinder. The switch
functions similarly to that of FIG. 3, but includes an air hose 82a
instead of a power cord 82 and includes an air hose 86a instead of
a socket 86. The air hose 82a is configured for connection to an
air supply and the air hose 86a is configured for connection to a
pneumatic power tool. The sensor for a pneumatic tool may be a flow
sensor, pressure sensor, reed switch, etc. When the pneumatic
sensor senses air flow to the pneumatic tool, a signal is sent to
the vacuum 50 via control cable 74.
[0031] Although a wired connection between a remote switch 70 and
the vacuum 50 is shown in FIGS. 3 and 4, a wireless connection is
also possible, and may be preferred in situations where the extra
cords may pose a safety risk or may simply hinder a worker's
performance. Typically, the port 66 and cord 74 are replaced by a
wireless transmitter and receiver, such as a radio frequency
transmitter and receiver.
[0032] Turning now to FIG. 5, a schematic diagram for the vacuum
and control system of the present invention is shown. The vacuum 50
may be operated in a conventional manner via switch 62. The vacuum
50 includes a controller 90 (such as a relay or a triac) to switch
the motor 94 on and off as is desired. An additional control module
98 may be utilized to operate the sensor 102 or perform other
functions. The vacuum 50 may be operated without the remote switch
70. Sensor 102 detects when a power tool connected to socket 58 is
being operated, such as by sensing the current drawn by the tool.
The sensor 102 is connected to the control module 98, which
receives and interprets signals from the sensor and sends a signal
to the module 90 to thereby operate the motor 94.
[0033] The control module 90 is programmed to optimize control of
the vacuum and provide additional functionality for a user.
According to a preferred embodiment, the control module 90 is
programmed to turn the motor 94 on when a power tool connected to
the socket 58 is turned on, and to turn the motor 94 off when the
power tool is turned off after the power tool has been operated for
longer than a predetermined time period, such as two seconds. If
the power tool is turned off after having operated for less than
two seconds, the control module 98 does not turn the motor 94 off.
The control module 90 is further programmed to always turn the
vacuum motor 94 off when the power tool ceases to be used if the
vacuum motor was running prior to operating the power tool, as this
would typically indicate that the operator desires to turn the
vacuum motor off after using the vacuum 50 without using the power
tool.
[0034] In this manner, the vacuum motor 94 will operate when the
power tool is being used and will turn off after discontinuing use
of the power tool, as nearly all uses of a power tool will require
longer than two to six seconds. The worker may, however, operate
the power tool for only a second or so to turn the vacuum motor 94
on and leave the motor on without the power tool being on. This
would allow the worker to clean up some debris or perform other
tasks requiring the vacuum but not the power tool. The worker may
then turn the vacuum off by again briefly turning the tool on. The
control module 98 thus allows a worker to switch the vacuum on and
off and operate the vacuum in a continuous run state without having
to operate the switch 62 on the vacuum itself. This is useful in
situations such as where the worker is on a ladder and does not
have the vacuum nearby. Preferably, the control module 98 is also
programmed to operate the vacuum motor 94 for a few seconds after a
worker uses a power tool for an extended period and then stops
using the power tool. In this manner, the vacuum motor captures any
debris which is within a tool dust shroud as the tool comes to
rest.
[0035] When the vacuum 50 is operated as described above, the power
tool and the vacuum motor 94 will still share power from a single
power cord 54, reducing the power available to the vacuum motor 94
while the power tool is operating. The vacuum 50 does, however,
allow a worker greater ease and flexibility in operating the vacuum
as described above. One benefit provided is that the vacuum motor
94 may continue to run for a few seconds after a worker
discontinues using a power tool. This increases the effectiveness
of the vacuum 50 in capturing the dust and debris which is
generated. An additional significant benefit is that the user may
remotely switch the vacuum on and off by quickly blipping the tool
on for less than a threshold period of time. This "cleanup" mode
allows the worker to capture any stray debris and otherwise use the
vacuum without using the power tool without having to turn the
vacuum on and off with switch 62. This significantly increases the
ease and effectiveness with which a worker may use the vacuum 50,
making it more likely that the worker will properly use the vacuum.
Increased worker compliance in using the vacuum 50 is highly
beneficial where the dust and debris is hazardous, such as when
grinding concrete or removing corrosion resistant paint.
[0036] In addition to the benefits discussed above, the remote
switch 70 allows a worker to operate a power tool in combination
with the vacuum 50 to control the vacuum without sacrificing vacuum
power. The remote switch also gives a worker a larger area where
the power tool may be used without moving the vacuum 50 itself. The
remote switch 70 uses a separate power source such as power cord 82
(or air supply line 82a) to provide power to a power tool. If the
power tool is electrical, the power cord 82 and power cord 54 will
typically be connected to different electrical circuits so that the
circuit breaker does not limit the available power, allowing both
the power tool and the vacuum motor 94 to operate at full
capacity.
[0037] In use, the remote switch 70 is connected to the vacuum via
cable 74 and port 66 (or wireless connection as discussed). The
remote switch 70 includes a sensor 106 which senses operation of
the power tool connected to the socket 86 (or air hose 86a). The
sensor 106 may sense current, voltage, or voltage drop for an
electrical power tool, or may sense air flow, pressure, or pressure
drop for a pneumatic power tool. When the sensor 106 senses that
the power tool is being operated, it sends an electrical signal via
cable 74 to the control module 98 to thereby trigger operation of
the vacuum motor 94 as discussed above. Typically, the remote
switch 70 sends either a voltage signal to the control module 98,
or provides continuity between two wires in cable 74. Providing
continuity between two wires is advantageous where a pneumatic
remote switch 70 is used, as a reed switch or the like which closes
the switch when air flow is present can be used to send a signal to
the control module 98 without any power requirement at the remote
switch 70. Thus, the remote switch 70 can connect two wires in
cable 74 to thereby provide a voltage signal, ground a terminal, or
provide electrical continuity within the control module 90. For
pneumatic tools, the sensor 106 may also receive power from the
vacuum itself so that the remote switch 70 does not need a separate
power supply. Alternately, pneumatic tools may utilize a reed
switch or other un-powered switch which simply opens or closes
continuity between two wires to indicate air flow. According to a
preferred embodiment, the remote switch may be provided with a
wireless transmitter 66a and the vacuum is provided with both a
port 66 and a wireless receiver 66b.
[0038] As is seen in FIG. 5, the signal output from the remote
switch 70 passes through the control module 98. As such, the use of
a tool connected to the remote switch uses all of the on/off
features as discussed above. The remote switch 70 thus allows a
power tool to control operation of the vacuum 50 as discussed above
without limiting the power available to the vacuum motor 94, and
allows a pneumatic tool to control operation of the vacuum motor.
The vacuum 50 will turn on and off with the power tool where the
power tool is used for extended periods of time, and the power tool
may be turned on briefly to place the vacuum in a continuous run
state. Where the power tool is electric, the power tool may draw a
high current such as 12 amps while still allowing the vacuum motor
94 to draw the intended current, often 10 to 12 amps. Because the
remote switch 70 controls the vacuum motor 94 via the control
module 90, the remote switch and associated power tool may be used
to turn the vacuum motor on and off and place the vacuum motor in a
continuous run state as described above to allow the worker to
clean up debris or perform other tasks which require only the
vacuum and not the power tool. Additionally, the use of an extended
cord 74 or a wireless connector 66a, 66b as discussed allows a
person greater range from the vacuum 50, allowing them to work more
freely without being encumbered by moving around the vacuum.
[0039] Turning now to FIGS. 6 and 7, electrical circuit diagrams
for the controller circuitry associated with the vacuum 50 and
remote switch 70 are shown to illustrate one manner in which the
electrical components of the above vacuum may be constructed. FIG.
6 illustrates circuits associated with the vacuum operation while
FIG. 7 illustrates circuits associated more with the remote switch
70.
[0040] Turning now to FIG. 6, a circuit 110 is shown to illustrate
one manner of construction for the vacuum 50 to implement the
methods discussed above. The circuit 110 includes the following
sections: a DC power supply 114, a current sensing circuit 118, a
micro-controller 122, a remote switch power supply circuit 126, a
remote switch input circuit 130, a zero crossing circuit 134, and a
output driver circuit 138. As discussed previously, a switch 62 may
be used to control the operation of the vacuum 50. Typically, a
three position switch 62 is used, having on off position, an on
position where the vacuum runs continuously, and an `auto` position
where the vacuum operation is controlled by the circuit 110. A DC
power supply 114 is typically used because most electronic
components are designed to operate on DC voltage where most vacuum
motors 94 operate on AC voltage.
[0041] As regards the particular electronic components, E1 through
E7 represent connections or connectors and J2-1 through J2-6 are
junctions. For the current sensing circuit 118, T1 is a CSE187L
current sensing transformer, R1 is a 68 ohm resistor, C5 is a 0.1
.mu.F capacitor, CR1 is a MBR0520 diode, R2 is a 2 k ohm resistor,
and C1 is a 1 .mu.F capacitor. For the DC power supply circuit 114,
CR3 are BAV23C diodes, C2 is a 220 .mu.F capacitor, and R3 is a 680
ohm resistor. For the zero crossing circuit 134, R4 is a 100 k ohm
resistor, CR2 is a 914 diode, and A2 is a PS2701 opto isolator. For
the output driver circuit 138, Q1 is a BTA24-600B triac, R7 is a
100 ohm resistor, R6 is a 560 ohm resistor, C4 is a 0.1 .mu.F
capacitor, R5 is a 1 k ohm resistor, A3 is a MOC3023 optocoupler,
R12 is a 10 k ohm resistor, and Q3 is a 2222 transistor. For the
microcontroller circuit 122, A1 is a 12HV615 PIC microchip. For the
remote start input circuit 130 and the remote start power supply
circuit 126, VR1 is a LM317LCPK integrated circuit, R10 is a 40 ohm
resistor, Q1 is a 2222 transistor, R8 is a 33 ohm resistor, and R9
is a 33 ohm resistor. For the remote surrent sensing circuit of
FIG. 7, T1 is a CSE187L, R1 is a 100 ohm resistor, CR1 is a 914
diode, CR2 is a MBR0520 diode, C1 is a 1 .mu.F capacitor, R2 is a
10 k ohm resistor, Q1 is a 2222 transistor, Q2 is a 2907
transistor, R4 is a 27 k ohm resistor, R3 is a 4.7 k ohm resistor,
DS1 is a LED, R5 is a 200 ohm resistor, CR3 is a HD04 bridge
diode.
[0042] In the circuit 110, the hot wire of the plug 54 is connected
to point 146 and the neutral wire of the plug 54 is connected to
neutral, the wire 150 is connected to the hot wire of the power
input plug 54, the hot wire of the vacuum motor 94 is connected to
point 154, and the neutral wire of the vacuum motor is connected to
neutral as indicated at 158.
[0043] The micro-controller 122, zero crossing circuit 134, and
output driver circuit 138 correspond to the functions performed by
the control module 90 as shown in the schematic diagram of FIG. 5.
The current sensing circuit essentially contains a current
transformer, a filter, and a rectifier. The output of the current
sensing circuit is connected to an analog to digital converter on
the micro-controller 122, and the micro-controller is capable of a
cycle by cycle reading of the total current level through the
system.
[0044] The zero output circuit 134 consists of a rectifier and
opto-isolated transistor. The output of this circuit is a square
wave with edges coincident with the zero crossings of the AC line
voltage. The output of the zero crossing circuit 134 is connected
to an internally pulled up input of the micro-controller 122. The
software in the micro-controller 122 is dependant on the
zero-crossing of the AC line voltage. The firing of the output
driver circuit must be in sync with the line voltage. When the
software senses the zero-crossing, the timings start for the phase
angle firing of the output driver to thereby adjust the power
output of the motor 94.
[0045] The basic operation of the micro-controller 122 is to sense
the current through the system as provided by the current sensing
circuit 118 and phase-angle fire both the positive and negative
waveforms to the output triac 162 driving the vacuum motor such
that the overall current of both the vacuum motor 94 and any power
tool connected to the socket 58 stays below a pre-determined limit.
The micro-controller 122 may also be programmed to include a
minimum amount of current that the vacuum motor 94 requires to
operate effectively. If the current to the vacuum motor 94 gets too
low, the vacuum motor will turn off until the attached power tool
is turned off.
[0046] The micro-controller 122 is preferably programmed to sense
when current through the line (socket 58) starts (corresponding to
a tool start when the vacuum switch 62 is in the auto position) and
turn on the vacuum motor 94 in response. The micro-controller 122
also senses a drop in the current (a tool shutoff) and turns the
vacuum motor off after about a 6 second delay to clear the vacuum
hose. The current drop sensing logic has about a 2 second startup
delay to allow for the transient effects of starting the power tool
and vacuum motor 94 to decay. This means that if the current start
logic sees a tool start, the vacuum will immediately turn on. If
the tool is turned off within the 2 seconds, the current drop
sensing logic will not see the tool current go away and the vacuum
will stay on indefinitely. As discussed, this allows a user to
remotely turn on the vacuum without keeping a tool running by
operating the tool for less than two seconds. This feature works
for both the socket 58, as sensed by the current sensing circuit
118 and the remote switch 70. In both cases the vacuum can be shut
off by turning the power tool on, then back off again, whether
quick or long, as the current drop sensing logic has been
enabled.
[0047] The vacuum circuit 110 may include a power supply circuit
126 to provide a small amount of power to the remote switch 70 if
such is necessary. Power may be provided to the remote switch 70 at
point 170. The remote start power supply circuit 126 typically
consists of a current limiter to prevent too much current being
drawn through the remote switch 70 and provides a voltage for the
remote sensing circuit. The output of the remote switch 70 is
connected to the remote switch input circuit 130 at point 174, and
drives a transistor 166 which is connected to an internally
pulled-up input of the micro-controller 122. When the remote switch
70 passes current, the micro-controller 122 will turn on the vacuum
motor 94. When the remote switch 70 ceases to pass current, or
ceases to display a current through a power line, the vacuum motor
94 will turn off after the 6 second delay. Circuit points 170 and
174 are typically a two pin connector used to connect the cable 74
to the vacuum 50 and thereby connect the remote switch 70 to the
controller circuitry 110.
[0048] It will be appreciated that if the remote switch 70 is used
instead of connecting an electrical power tool directly to the
socket 58, the remote switch may be connected to a wall outlet on a
separate circuit breaker so that the vacuum 50 and power tool do
not have to share power. Thus, the power tool may draw current and
the vacuum motor 94 may draw full current without concerns of
overloading the circuit. Even if the remote switch 70 is used, the
internal logic of the microcontroller 122 may still operate to keep
the overall current of the vacuum below the pre-determined level by
phase angle firing the vacuum motor if needed. This may provide
some protection if the vacuum motor 94 alone attempts to draw an
unusually high current.
[0049] Turning now to FIG. 7, a circuit diagram for a remote switch
70 for use with electrical power tools is shown. The remote switch
70 would include a current sensing circuit 178 which consists of a
current transformer 182 which drives a transistor network so as to
provide a signal to the micro-controller 122 through point 190 as
soon as current is sensed. Point 186 and 190 on the remote switch
current sensing circuit 178 are connected to points 170 and 174,
respectively, on the vacuum circuit 110 when the remote switch 70
is used. The current transformer 174 and transistor network are
preferably selected such that the current sensing circuit 178 is
activated with about 1 Amp of current and thereafter drives the
circuit 178 to give a logic change to the micro-controller 122. The
current limited voltage from the remote start power supply circuit
126 may be used to power the remote sensor circuit 178.
[0050] Turning now to FIG. 8, a functional parts diagram for a
remote switch 70 for use with pneumatic tools is shown. As
discussed, the use of a remote switch 70 allows for controlling the
vacuum 50 based on the usage of pneumatic tools. In this case, the
remote sensor may be a simple switch. There may be no electronics
in the remote switch 70 other than a reed switch or simple switch
that closes when air is passing through the switch and opens when
the air stops flowing.
[0051] Thus, the pneumatic remote switch 70 may include a switch
198 that is closed so as to conduct electricity when air flows
through an air passageway 202. As shown in FIG. 4, the passageway
202 is typically connected to an air hose 82a which is configured
for connection to an air supply and an air hose 86a which is
configured for connection to a pneumatic power tool. The switch 198
is connected via electrical leads to points 206, 210, which are
connected to points 170, 174 on the circuit 110 when the remote
switch 70 is connected to the vacuum via cable 74. Thus, point 206
provides an electrical voltage to the switch 198. When the switch
198 is closed due to air flow, the voltage is transmitted to point
210 and thereby to point 174 on circuit 110 to cause the
micro-controller 122 to operate the vacuum motor in the manner
discussed above. Alternatively, the switch 70 may use a wireless
transmitter 66a as discussed.
[0052] There is thus disclosed an improved system for controlling
the operation of a vacuum with an associated power tool. It will be
appreciated that numerous changes may be made to the present
invention without departing from the scope of the claims.
* * * * *