1. The Field of the Invention
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.
2. State of the Art
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.
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.
As shown in
The prior art vacuum of
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.
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.
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.
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.
According to another aspect of the invention, the vacuum may be switched into and out of a continuously operating state remotely.
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.
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.
Various embodiments of the present invention are shown and described in reference to the numbered drawings wherein:
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.
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.
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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.
Although a wired connection between a remote switch 70 and the vacuum 50 is shown in
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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.
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.
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.
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.
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.
As is seen in
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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 μF capacitor, CR1 is a MBR0520 diode, R2 is a 2 k ohm resistor, and C1 is a 1 μF capacitor. For the DC power supply circuit 114, CR3 are BAV23C diodes, C2 is a 220 μF 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 μF 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
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.
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
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.
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.
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.
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.
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.
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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
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.
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.
Number | Date | Country | |
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61022506 | Jan 2008 | US |