U.S. patent application number 09/768380 was filed with the patent office on 2001-07-12 for adaptive/reactive safety plug receptacle.
This patent application is currently assigned to Power-Off Products, LLC. Invention is credited to Skarie, Christopher Jason, Skarie, Loren Paul.
Application Number | 20010007800 09/768380 |
Document ID | / |
Family ID | 22838198 |
Filed Date | 2001-07-12 |
United States Patent
Application |
20010007800 |
Kind Code |
A1 |
Skarie, Christopher Jason ;
et al. |
July 12, 2001 |
Adaptive/reactive safety plug receptacle
Abstract
Disclosed is an electrical receptacle which is safe for children
yet easy for adults to use. This electrical receptacle provides
power only to a properly inserted plug and makes use of one or more
sensors which are able to detect blade insertion, ground plug
insertion, presence of the plug face motion near the receptacle
face or a combination thereof. The receptacle includes a contact
assembly adapted and configured to conductively couple each blade
of the plug to a conductor, one or more sensors, and a control
circuit; wherein the control circuit determines whether or not to
provide power to the properly inserted plug by determining if
substantially simultaneous insertion has occurred.
Inventors: |
Skarie, Christopher Jason;
(Audubon, MN) ; Skarie, Loren Paul; (Vergas,
MN) |
Correspondence
Address: |
Mark T. Skoog
MERCHANT & GOULD P.C.
P.O. Box 2903
MInneapolis
MN
55402-0903
US
|
Assignee: |
Power-Off Products, LLC
Detroit Lakes
MN
|
Family ID: |
22838198 |
Appl. No.: |
09/768380 |
Filed: |
January 22, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09768380 |
Jan 22, 2001 |
|
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09223848 |
Dec 31, 1998 |
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6176718 |
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Current U.S.
Class: |
439/188 |
Current CPC
Class: |
Y10S 439/955 20130101;
H01R 13/64 20130101; H01R 13/6641 20130101; H01R 13/7175 20130101;
H02H 5/12 20130101; H01R 13/7038 20130101 |
Class at
Publication: |
439/188 |
International
Class: |
H01R 029/00 |
Claims
We claim:
1. An electrical receptacle which provides power only to a properly
inserted plug, said receptacle comprising: a contact assembly, a
relay assembly, an LED, a photodetector, a plug component sensor
and a control circuit; the contact assembly being adapted and
configured to coiductively couple each blade of the plug to a relay
assembly; the relay assembly being adapted and configured to
conductively couple the contact assembly to a conductor; the plug
component sensor comprising a diffuse reflective sensor comprising
the LED and the photodetector; wherein the LED emits light which is
reflected by a component of a properly inserted plug and is
detected by the photodetector, thereby signaling the control
circuit to provide power to the properly inserted plug.
2. The electrical receptacle of claim 1 wherein the plug component
sensor comprises a blade sensor, a ground prong sensor, or a face
sensor.
3. The electrical receptacle of claim 1 wherein the receptacle
further comprises a motion sensor.
4. The electrical receptacle of claim 3 wherein the control
circuitry requires that the motion sensor sense no motion proximal
to the receptacle for a period of at least about 300 ms prior to
permitting power to flow.
5. The electrical receptacle of claim 1 wherein the receptacle is
hardwired into an electrical system.
6. The electrical receptacle of claim 1 wherein the receptacle is
plugged into a hardwired outlet.
7. An electrical receptacle which provides power only to a properly
inserted plug, said receptacle comprising: a contact assembly, a
relay assembly, two plug component sensors and a control circuit;
the contact assembly being adapted and configured to conductively
couple each blade of the plug to the relay assembly; the relay
assembly being adapted and configured to conductively couple the
contact assembly to conductors; wherein the control circuit
determines presence of a properly inserted plug and provides power
upon substantially simultaneous sensing by the plug component
sensors.
8. The electrical receptacle of claim 7 wherein the control circuit
provides power if at least two plug component sensors sense plug
components within a period of less than about 1 second.
9. The electrical receptacle of claim 7 wherein the control circuit
provides power if at least two plug component sensors sense plug
components within a period of about 100 to about 300
milliseconds.
10. The electrical receptacle of claim 7 wherein the plug component
comprises a blade, a ground prong, or a combination thereof.
11. The electrical receptacle of claim 10 wherein the plug
component sensor comprises a through beam sensor, a diffuse
reflection sensor, a capacitance sensor, a mechanical sensor, or a
combination thereof.
12. The electrical receptacle of claim 7 wherein the plug component
comprises a plug face.
13. The electrical receptacle of claim 12 wherein the plug
component sensor comprises a diffuse reflective sensor.
14. The electrical receptacle of claim 7 wherein the plug component
sensor further comprises a motion sensor.
15. The electrical receptacle of claim 7 wherein the control
circuitry requires that the motion sensor sense no motion proximal
to the receptacle for a period of at least about 300 ms prior to
permitting power to flow.
16. The electrical receptacle of claim 7 wherein the receptacle is
hardwired into an electrical system.
17. The electrical receptacle of claim 7 wherein the receptacle is
plugged into a hardwired outlet.
Description
BACKGROUND OF THE INVENTION
[0001] There has been a long-felt need for electrical receptacles
or outlets which are safer; especially for children. Conventional
electrical receptacles allow several possibly dangerous situations
to occur. One situation results from foreign objects such as paper
clips or car keys inserted into the receptacle. If the object is
conductive, the person holding the foreign object acts as a
conductor, thereby permitting current to flow through the object
and through the person. This situation is more likely among
children. While adults know better than to insert foreign objects
into a receptacle, they are nevertheless not immune to the possible
dangers. Adults can receive a shock by improperly holding or
grasping the plug while inserting or removing it from the
receptacle, since it is possible to make contact with one or more
of the conducting blades while grasping the plug.
[0002] Conventional house electrical systems operate at about
110-120 volts, which is sufficient to possibly cause serious
damage. Children are especially vulnerable to the effects of
electricity. Consequently, a need has been recognized for safer
electrical receptacles.
[0003] Some of the more common solutions in the past have utilized
mechanical structures which prevent direct insertion of foreign
objects. An example includes a plastic device inserted into a
receptacle. This device has a flat surface which covers the face of
the receptacle and several plastic blades which fit into the
receptacle, thereby holding the device firm. While in place, these
plugs prevent insertion of any foreign objects into the receptacle.
Unfortunately, these plugs can be removed, rendering their safety
efficacy nonexistent. If not removed, they present an obstacle to
adults who wish to use the receptacle.
[0004] Another solution replaces the receptacle cover with a device
which prevents direct insertion. One style requires the user to
partially insert the plug into the receptacle, and then rotate
90.degree. to gain insertion. Another style includes the same
partial insertion step, but requires a subsequent lateral
translation to gain complete insertion. These structures can't
completely prevent insertion of foreign objects, and can be
ungainly as they are mounted in front of the receptacle in place of
a conventional receptacle cover.
[0005] Other solutions include mechanical switching within a
modified receptacle. For example, an inserted plug can have one or
more blades that can activate such a switch. Alternatively, the
receptacle can require use of a modified plug which contains one or
more pins for switch activation. These solutions, unfortunately,
include mechanical moving parts which are prone to wear or require
the user to replace the plugs on all electrical devices. Further
each of these possible solutions require user interaction.
Typically, if a user is required to perform additional steps to
operate a modified receptacle, they will often not bother and will
eventually replace the modified receptacle with a standard
outlet.
[0006] Another solution includes the use of optics; specifically, a
light beam which can be interrupted by plug insertion. Typically,
no power would flow while the light beam is uninterrupted,
indicating that no plug is present. When a plug is inserted, the
light beam is interrupted and power is allowed to flow. This
solution may assist in preventing shocks caused by improperly held
plugs (since the plug may need to be completely inserted to block
the light beam, the user is unable to make contact with the plug
blades). Unfortunately, any inserted object of a particular minimum
size will block the light beam and permit power to flow. While this
avoids the complexity of moving mechanical parts, insertion of most
foreign objects would permit current to flow. This solution lacks
the sophistication necessary to provide a receptacle which is safe
for both children and adults.
[0007] A substantial need remains for electrical receptacles which
are safe for children yet easy for adults to use. Preferably, such
an electrical receptacle would also have the ability to prevent
shocks caused by partial plug insertion.
SUMMARY OF THE INVENTION
[0008] Accordingly, the invention includes an electrical receptacle
which is safe for children yet is easy for adults to use. A novel
combination of sensors and circuitry within the receptacle prevent
shocks caused by insertion of foreign objects and by improperly
grasping a partially inserted plug. The receptacle has one or more
plug component sensors that can detect blade insertion, ground
prong insertion, presence of the plug face, motion near the
receptacle face, or a combination thereof.
[0009] The electrical receptacle of the invention can include a
plurality of plug component sensors for the purpose of determining
the presence or absence of specific geometric features of a
standard plug. Examples of plug component sensors include a blade
sensor, a ground prong sensor and a face sensor. The electrical
receptacle of the invention can utilize any combination of these
sensors. Each plug component sensor reports the proximal presence
or absence of a plug component or foreign object in the space
occupied by the plug component in a properly inserted
condition.
[0010] In one embodiment, the receptacle of the invention includes
a contact assembly, a relay assembly, an LED, a photodetector, a
plug component sensor and a control circuit. The contact assembly
is adapted and configured to selectively and conductively couple
each blade of the plug to the relay assembly while the relay
assembly is adapted and configured to conductively couple the
contact assembly to conductors. Preferably, the plug component
sensor includes a diffuse reflective sensor including the LED and
the photodetector; wherein the LED emits light which is reflected
by a component of a properly inserted plug and is detected by the
photodetector, thereby signaling the control circuit to provide
power to the properly inserted plug. A properly inserted plug is
defined as one which is completely inserted into the receptacle;
thereby permitting power to flow to the plug without risking shock
caused by contact with a partially inserted plug.
[0011] The invention also includes an electrical receptacle having
two or more plug component sensors. In one embodiment including a
control circuit, this permits a control circuit to determine if
substantially simultaneous insertion has occurred. Plug geometry
requires that a properly inserted plug will present any individual
components such as blades and ground prongs at virtually the same
time. If individual sensors detect time delayed insertion, it is
likely that one or more foreign objects have been inserted. In that
situation, the control circuit would not permit power to flow.
Substantially simultaneous detection of component insertion can be
required to cause power to flow.
[0012] The electrical receptacle of the invention includes a
contact assembly, which is adapted and configured to conductively
couple each blade of the plug to a conductor. For this invention,
the electrical state of the contact assembly is determined by the
relays, as the contact assembly is conductively coupled to (a)
relay(s).
[0013] The electrical receptacle of the invention includes a
control circuit which determines presence of a properly inserted
plug, and may also ensures no activity in the immediate vicinity of
the plug, or other features of the receptacle's environment. The
electrical receptacle of the invention can utilize any combination
of the plug component sensors and any signal analysis method(s).
Electrical control which requires substantially simultaneous
detection of two or more plug components virtually eliminates the
possibility of accidental shock or electrocution as a result of
inserting foreign objects.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic illustration of an embodiment in which
a diffuse reflective blade sensor detects the presence of a single
inserted blade.
[0015] FIG. 2 is a schematic illustration of an embodiment in which
a through beam sensor is employed to detect the presence of an
inserted blade tip.
[0016] FIG. 3 is a schematic illustration of a through beam sensor
in which a distinct LED and photodetector detects each inserted
blade tip.
[0017] FIG. 4 is a schematic illustration of another through beam
sensor in which a single LED emits light which is detected by a
pair of photodetectors, each photodetector corresponding to a
single inserted blade.
[0018] FIG. 5 is a schematic illustration of an embodiment in which
a through beam sensor is employed to detect the blade aperture of
an inserted blade.
[0019] FIG. 6 is a schematic illustration of an embodiment in which
a through beam sensor is employed to detect the blade aperture of
an inserted blade.
[0020] FIG. 7 is a schematic illustration of a face sensor
employing a diffuse reflective sensor. In this embodiment, an LED
and a photodetector are mounted in sloped planes of the receptacle;
permitting a plug face to reflect emitted light back to the
photodetector.
[0021] FIG. 8 is a schematic illustration of an alternate
embodiment of a face sensor employing a diffuse reflective sensor
according to the invention. In this embodiment, the LED and the
photodetector are instead mounted within the receptacle; wherein
the receptacle contains a clear plastic portion which allows the
LED to emit light which can be reflected back (by a plug face) to
the photodetector.
[0022] FIG. 9 is a schematic illustration of an optical sensor
according to the invention. An optical sensor can be employed to
detect either motion or proximity.
[0023] FIG. 10 is a circuit schematic illustrating the circuitry
necessary to control an embodiment having two blade sensors.
[0024] FIG. 11 is a circuit schematic illustrating the circuitry
necessary to control an embodiment having two blade sensors and a
face sensor.
[0025] FIG. 12 is a circuit schematic illustrating the circuitry
necessary to control an embodiment having both a blade tip sensor
and a blade aperture sensor. A user-removable jumper allows the
user to determine if the receptacle requires sequential detection
of a blade tip followed by the blade aperture.
[0026] FIG. 13 is a circuit schematic illustrating the circuitry
necessary to control an embodiment having two blade sensors and a
face sensor. This schematic also shows an optional relay
assembly.
[0027] FIG. 14 is a circuit schematic illustrating the circuitry
necessary to control an embodiment having two blade sensors, a face
sensor and a motion detector. This schematic also shows an optional
relay assembly.
[0028] FIG. 15 is a circuit schematic illustrating the circuitry
necessary to control an embodiment having a blade tip sensor, a
blade aperture sensor, a face sensor and a motion detector. A
user-removable jumper allows the user to determine if the
receptacle requires sequential detection of a blade tip followed by
the blade aperture.
[0029] FIG. 16 is a schematic illustrating an adaptive receptacle
according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0030] A variety of electrical receptacles are known to those of
skill in the art. These receptacles include the traditional 110 V
duplex grounded receptacle commonly used in the home and office.
Specialty receptacles include those intended for higher voltages,
such as for air conditioners and other major appliances. Such
typical receptacles can utilize the sensors and circuitry described
in the invention.
[0031] As used herein, the term "receptacle" refers to a structure
which serves to conductively couple an electrical plug to a source
of electricity via a contact assembly. A common form of a
receptacle is the duplex outlet found in most homes and offices.
Typically, these outlets are hardwired into the electrical system,
meaning that they are conductively and permanently attached and are
typically mounted within a wall. However, the term "receptacle" can
also refer to the individual outlets found in outlet strips, and in
gang boxes. The female end of an extension cord also qualifies as a
receptacle. Typically, outlet strips and extension cords are merely
plugged into a hardwired receptacle. Gang boxes are typically
plugged in, but are also bolted to the receptacle as a replacement
for the receptacle cover.
[0032] Receptacles typically include a set of metal (usually
copper) conducting pieces within a plastic form. These conducting
pieces serve to electrically connect an inserted plug to the home
or office electrical system. These metal conducting pieces are, for
the sake of this application, described as a contact apparatus
which is adapted and configured to conductively couple each blade
of a plug to a relay assembly which is conductively coupled to the
conductors. The plastic form serves to hold the conducting pieces
within the receptacle in proper orientation.
[0033] A plug typically has two conducting blades which connect the
electrical apparatus to the hot and neutral conducting leads from
the electrical system. The electrical apparatus can be any
electrical apparatus, such as a light, a radio, television, tool
and the like. The plug is attached to conductive leads which are
electrically connected to the electrical appliance. A plug may
optionally have a ground prong, which serves to electrically
connect the electrical apparatus to the ground portion of the
electrical system.
[0034] An electrical receptacle or outlet serves several purposes.
First, it must hold an inserted plug firmly in place. Second, it
must serve to electrically connect the inserted plug to the
electrical system. A plug can be considered to be the connective
portion of an electrical apparatus while an electrical receptacle
can be considered to be the connective portion of an electrical
system. An electrical system is the source of power to the
receptacle, and is typically defined to be the wiring within a home
or office. This wiring is conductively connected to each receptacle
within the building, and serves to provide electricity to each
outlet.
[0035] The invention is found in an electrical receptacle which
provides power only to a properly inserted plug. Typically, the
invention includes a receptacle having two or more plug components
sensors that can detect blade insertion, ground plug insertion,
presence of the plug face, or the presence of any other specific
feature of a standard plug. The receptacle has a contact assembly
that is adapted and configured to conductively couple each blade of
the plug to a conductor and also has relays, contacts, or any other
power control device which can conductively couple the contact
assembly to the electrical system. This allows power to be supplied
to the receptacle under the direction of the control circuit in the
event that the control circuit determines the presence of a
properly inserted plug. The receptacle can have a motion detector
to determine if there is motion in the immediate vicinity of the
receptacle.
[0036] The electrical receptacle of the invention also includes a
plurality of plug component sensors for the purpose of determining
the presence or absence of specific geometric features of a
standard plug. Examples of plug component sensors include a blade
sensor, a ground prong sensor and a face sensor. The electrical
receptacle of the invention can utilize any combination of these
sensors. Each plug component sensor reports the proximal presence
or absence of a plug component or foreign object in the space
occupied by the plug component in a properly inserted condition.
Preferably, the plug component sensors are of a "diffuse
reflective" type, recognizing that a plurality of sensor types can
be used to detect plug components. The diffuse reflective sensor
includes an LED and photodetector, which may or may not be
modulated, wherein the LED emits light which is reflected by a
component of a properly inserted plug or foreign object and is
detected by the photodetector, thereby signaling the control
circuit the occupation status of the volume of space in the
immediate vicinity of the plug component sensor.
[0037] The adaptive outlets of the invention preferably include a
motion sensor. It is unlikely that a person inserting a plug can
remain entirely motionless while inserting a plug. Consequently, it
is preferred that the motion detector report to the control
circuitry the presence or absence of motion in the immediate
vicinity of the receptacle face. The motion detector type is
required to function regardless of the mass in the immediate
vicinity of the outlet. Should a transformer or bulky plug be
inserted, the outlet adapts to the stationary additions to the
environment while determining the presence of motion within the
vicinity.
[0038] The safety aspects of the invention are truly found in the
circuitry which controls the adaptive outlet. Preferably, the
adaptive outlet includes at least two plug component sensors,
thereby permitting the control circuitry to determine the plug
component sensors were tripped in a substantially simultaneous
fashion; meaning that all plug component sensors present in a
receptacle detected their assigned plug components within a short
period of time. Electrical control which requires substantially
simultaneous detection of two or more plug components substantially
eliminates the likelihood of accidental shock or electrocution as a
result of inserting foreign objects. Addition of a motion sensor to
prevent the power from flowing while motion is present, regardless
of the status of the significantly simultaneous plug component
detection, substantially eliminates the likelihood of accidental
shock caused by contact with partially inserted conductive blades
or foreign objects that provide the significantly simultaneous
criteria. This feature insures that the receptacle does not supply
power while an object or a person's hand is in the immediate
vicinity of the outlet. The control circuit can only allow the
relay or contact assembly to supply power after any non-stationary
object is absent from the area, or has been absent for a
predetermined period of time.
[0039] Plug Component Sensors
[0040] The purpose of the plug component sensors is to determine
the presence or absence of an object in a specific region in space
near the receptacle. That space is generally only occupied by a
specific geometric feature of a standard plug, but may also be
occupied by a foreign object. The adaptive receptacle preferably
has at least two plug component sensors. Each plug component sensor
reports the proximal presence or absence of a plug component or
foreign object in the space occupied by the plug component in a
properly inserted condition.
[0041] Examples of plug component sensors include blade sensors,
ground prong sensors and face sensors. It is recognized that there
are many significant features of a standardized plug that would
qualify as a recognizable plug component, and as such, can be
detected by a sensor. The electrical receptacle of the invention
can utilize any combination of these sensors.
[0042] Blade Sensors
[0043] The diffuse reflective sensor includes an LED and
photodetector, which may or may not be modulated, wherein the LED
emits light which is diffusely reflected by a component of a
properly inserted plug or foreign object and is detected by the
photodetector, thereby signaling the control circuit the occupation
status of the volume of space in the immediate vicinity of the plug
component sensor. Diffuse reflector sensors have the emitting and
sensing elements viewing the same side of the target.
[0044] Reflection is defined herein as the return of light waves
from any surface. A shiny surface such as a mirror is not required.
All objects are made visible by the light they reflect. This is
often referred to as diffuse reflection.
[0045] For this and other sensor types, referral to a
"photodetector" indicates that the photodetector is configured to
sense light of an appropriate wavelength or modulation as emitted
by the LED. Referral to an "LED" indicates that the LED is
configured to emit light at any appropriate wavelength at any
appropriate modulation. The wavelength and modulation can be
selected or determined by one skilled in the art.
[0046] One or more reflective surfaces can be used either to
reflect the emitted light passing to the receptacle blade aperture,
or to reflect the light that passes through the receptacle blade
apertures, then continues to the photodetector. Further, fiber
optics can be employed in such a way as to allow for positioning of
the LED and photodetector anyplace beneficial.
[0047] Typically, blade sensors can be employed to detect more than
one portion of an inserted blade. For example, a blade sensor can
be configured to detect insertion of the distal end (furthest from
the plug face) of an inserted blade. This sensor is considered to
be a blade tip sensor. Such a sensor can be positioned within a
receptacle so that insertion is not detected unless the blade is
completely inserted. Alternatively, a blade sensor can be located
at a position corresponding to the blade aperture of a fully
inserted blade. As the blade is inserted, the sensor acts first as
a blade tip sensor, detecting passage of the blade tip past the
sensor. Then, the sensor can act as a blade aperture sensor,
detecting the presence of the blade aperture, thereby indicating a
completely inserted blade. The control circuitry can be designed
for either use of a blade sensor.
[0048] FIG. 1 shows a typical diffuse reflective blade sensor which
includes a single LED and a single photodetector, which are used to
detect insertion of a single blade or foreign object. A diffuse
reflective sensor can be used to detect any portion of an inserted
blade. Seen is a blade 100 with a round aperture (not shown), an
LED 140 on a first sloped plane 180, and a photodetector 160 on a
second sloped plane 190. These structures are shown in relation to
the receptacle 120 and circuit board 150. The LED 140 emits light,
some of which can be reflected from the blade 100 to strike the
photodetector 160. Consequently, a properly inserted blade 100 is
detected by a characteristic amount of emitted light striking the
photodetector 160 after being reflected from the blade 100. Too
little returned light means that either the LED 140 is burned out
or a smaller or light absorbing foreign object has been inserted.
In this case, the plug component sensor would indicate a
unacceptable condition. If a characteristic amount of light is
observed, this plug component sensor would indicate an acceptable
condition. If an acceptable condition is reported to the control
circuit, the relay assembly will then permit power to flow through
the receptacle.
[0049] Through beam sensors operate by detecting and reporting to
the control circuit incidences of interruption of a light beam by
the blades of a properly inserted plug, or by a foreign object.
Through beam sensors have a direct or indirect path between an
emitting and receiving element. The light source can be an LED or
any other source of electromagnetic radiation of any wavelength(s).
The photodetector is one that can be matched to detect light from
the chosen light source. If the light path is indirect, one or more
reflective surfaces can be employed to aim the emitted or reflected
light in the necessary direction. Further, fiber optics can be
employed in such a way as to allow for positioning of the LED and
photodetector anyplace beneficial.
[0050] A maximum amount of emitted light will strike the
photodetector when no blade is present. If a foreign object or a
plug blade is inserted, some or all of the emitted light will be
blocked. Consequently, a properly inserted blade is characterized
by a total or significant reduction in transmitted light. This
method has the disadvantage of being unable to distinguish between
a plug blade and an adequately configured foreign object. However,
if the sensor is configured so the blade only partially blocks the
light path when properly inserted, the control circuit can
determine if the LED is still functioning.
[0051] FIG. 2 shows a typical through beam blade sensor including a
single LED and a single photodetector, which is used to detect
insertion of a single blade or a foreign object. In this
embodiment, the blade sensor is configured as a blade tip sensor.
The figure shows a blade 200 with a round aperture 220. An LED 240
emits light, some or all of which can be blocked from passing
through the blade aperture 220 to strike the photodetector 260.
Consequently, a properly inserted blade 200 is detected by a
characteristic amount of emitted light striking the photodetector
260 after passing through the receptacle blade aperture. A greater
than characteristic amount of light means that either no blade 200
is present, or a small object such as a paper clip has been
inserted. Too little light means that either the LED 240 is burned
out or a larger or adequately shaped foreign object has been
inserted. In either case, too little or too much light, the plug
component sensor would indicate a unacceptable condition. If a
characteristic amount of light is observed, this plug component
sensor would indicate an acceptable condition.
[0052] FIG. 3 shows a blade tip sensor embodiment in which a
centrally located LED 340 is used to provide incident light which
may strike the photodetectors 360. Each blade is seen with an
aperture 320. For light to pass successfully through the receptacle
blade apertures for each blade 300, the light path must be
perpendicular to the long axis of both the blades 300 as well as
the axis running the width of the blade 300. As illustrated, one
way to do this is to align the LED 340 and the photodetector 360
through the blade apertures. In essence, the LED 340 is aimed
directly at the photodetector 360 through the location the blades
300 will reside within the receptacle blade aperture.
[0053] FIG. 4 shows an embodiment having one centrally located
common LED 440 to illuminate the corresponding photodetectors 460
for each blade 400 and the ground prong 450. This figure is a
heads-on view of an inserted 3 conductor plug. This embodiment may
alternatively have any number of prongs or blades or blade
apertures to be sensed. Seen is the LED 440, which emits light
which can pass through apertures (not shown) in blades 400, thereby
striking the photodetector 460. Also noted is the ground prong 450
and the-blades 400, which can prevent the light emitted from the
LED 440 from striking the photodetector 460.
[0054] It is recognized that there are a variety of sensing methods
that may be used as a plug component sensor for the plug blade,
including various mechanical sensors. The sensor must be able to
provide a signal to the control circuit.
[0055] In addition to having two or more blades, many plugs have a
ground prong as well, which can also be used for detection of a
properly inserted plug, and to insure that the appliance cord is
grounded. A ground prong sensor may frequently be used in
conjunction with a blade sensor, as seen in the blade hole sensor
figure with simultaneous blades and blade holes and prong
detection. As with the blade and blade aperture sensors, ground
prong sensors can include diffuse reflective and through beam
sensors.
[0056] FIG. 5 is similar to FIG. 2, except that it denotes a blade
sensor configured as a blade aperture sensor. Seen in the figure is
a blade 500 with aperture 520. LED 540 is positioned and configured
such that a portion of the emitted light can pass through aperture
520 of properly inserted blade 500 and strike photodetector 560.
The amount of incident light on the photodetector 560 indicates to
the control circuitry the presence or absence of either a properly
inserted plug or a foreign object or improperly inserted plug.
[0057] FIG. 6 is similar to FIG. 3, except that it denotes a blade
sensor configured as a blade aperture sensor. Unlike FIG. 5, this
figure uses a single LED 640 to provide incident light on both
photodetectors 660. Seen in the figure is plug body 680, holding
blades 600 with blade apertures 620. The LED 640 is positioned and
configured such that a portion of the emitted light can pass
through apertures 620 of each properly inserted blade 600 and
strike each photodetector 660. As before, the amount of light
incident on each photodetector 660 signals the presence or absence
of a properly inserted plug.
[0058] Face Sensors
[0059] A face sensor as defined herein relates to a sensor that can
detect the presence or absence of an object in the region of space
around the receptacle that corresponds to the location of the plug
"face" when inserted properly. A plug face is defined as the
reasonably flat area located on the body of a plug, between the
blades. Face sensors according to the invention can include diffuse
reflective sensors, capacitive and acoustic sensors.
[0060] FIG. 7 shows a face sensor according to the invention, and
includes an LED 740 and a photodetector 760 mounted on sloped
planes 780 and 790, respectively on the surface of the receptacle
face 720. These planes are angled such that an encroaching plug
face 770 will reflect the light emitted by the LED 740 onto the
photodetector 760. When no light is present, the emitted light
simply angles out away from the receptacle. Also seen in this
figure is a circuit board 750. This figure is similar to FIG. 1,
however, the sensed component is the plug face 770 as opposed to
the blade.
[0061] FIG. 8 shows an alternative embodiment of the face sensor
wherein the LED 840 and photodetector 860 are directly mounted onto
the circuit board 850. In this case, the LED emits light which can
pass through the transparent block 830, strike the plug face 870,
and then is reflected back through the transparent block 830 to the
photodetector 860. This embodiment has the advantage of not
requiring the LED or photodetector to be exposed on the surface of
the receptacle. Also, the transparent plastic may be transparent or
opaque in the wavelengths of the emitter. It is not required to be
transparent or opaque in any other frequencies. This would allow
the use of black, IR transparent plastic for the window. This type
of application can also work for blade and blade aperture
sensors.
[0062] Capacitive sensors monitor for changes in the dielectric
constant between capacitor plates with known properties. Placement
of an object (the plug) near the sensor causes the material in
front of the capacitor insulation to change from air to plastic,
thus changing the dielectric constant of the material in the field
lines of the plate. This dielectric constant change causes a change
of capacitance between the two plates. The change of capacitance is
easily monitored by circuitry known to one skilled in the art.
[0063] Acoustical sensing employs a sound emitter and a microphone.
When the plug face is not present, the sound emitter projects
acoustical energy away from the receptacle. This sound may be of
nearly any reasonable frequency or intensity. If the plug face is
present, a portion of the acoustic energy will be reflected back
towards the receptacle, and to the microphone. In the presence of a
seated plug, the acoustical energy entering the microphone will be
higher than with no plug.
[0064] It is recognized that there are a variety of sensing methods
that may be used as a plug component sensor for the plug face. One
of skill in the art will realize that any geometrical feature of
the outlet may be sensed, and qualify as a legitimate plug
component sensor location. Any of the mentioned plug component
sensors, as well as others, can be used as a sensing method for
these additional sensors.
[0065] Motion and Proximity Sensors
[0066] Another source of electrical shock results from making
contact with the exposed conducting blades of a partially inserted
plug. It is therefore desirable to determine if there is motion in
the immediate vicinity of the outlet. Thus, the outlets of the
invention preferably include a motion sensor. It is unlikely that a
person inserting a plug or a foreign object can remain entirely
motionless. Consequently, it is preferred that the motion detector
report to the control circuitry the presence or absence of motion
in the immediate vicinity of the receptacle face.
[0067] In this instance, "immediate vicinity" is defined as within
about 8 cm, preferably no more than about 4 cm of the receptacle.
The motion detector type is required to function regardless of the
mass in the immediate vicinity of the outlet. Should a transformer
or bulky plug be inserted, the outlet adapts to the stationary
additions to the environment while still determining the presence
of motion within its immediate vicinity.
[0068] One such technology employs capacitive plates, and is called
a capacitive sensor. As discussed, capacitive sensors monitor for
changes in the dielectric constant between capacitor plates with
known properties. The output of a capacitive sensor can also be AC
coupled, effectively allowing only the effects of motion of a mass
in the immediate vicinity of the capacitive sensor to affect the
sensor output. These flat plates can be mounted behind the
receptacle cover, as well as other locations, and can change their
capacitance according to the dielectric constants of all of the
materials within the field lines of the plates. Consequent of that,
and the AC coupling, this sensing method can be adapted to various
installation options, as the sensing plates can be mounted behind
any designer or styled receptacle cover, and the motion detection
circuitry allows only the properties from only moving objects to
affect the output of the sensor.
[0069] As previously mentioned, a source of electrical shock
results from making contact with the exposed conducting blades of a
partially inserted plug. It may then be desirable to determine if
there is an object present somewhere in the immediate vicinity of
the outlet. Thus, the outlets of the invention preferably include a
proximity sensor. It is unlikely that a person inserting a plug or
a foreign object can entirely avoid certain regions in space around
the receptacle. Consequently, it is preferred that the proximity
detector report to the control circuitry the presence or absence of
motion in the immediate vicinity of the receptacle face. In this
instance, "immediate vicinity" is defined as within about 10 cm,
preferably no more than about 5 cm of the receptacle
[0070] An optical sensor that may be used for motion detection
would monitor for changes in optical intensity near the receptacle.
Provided a light source is embedded on the surface of the
receptacle for the purpose of illuminating any object in front of
the receptacle, but within a cone defined by the optics of the
light source, and the photodetector is configured with optics to
view a conical shaped area that intersects the light cone, the
optical intensity received by the photodetector will change if an
object enters the intersection of the two cones. An increase in the
received optical intensity would then constitute a unacceptable
condition.
[0071] FIG. 9 shows an embodiment of an optical sensor which can
sense either motion or proximity. A moving object which intersects
one or more of the light beams will change the amount of light
incident on the photodetector. A stationary object will have much
the same effect, particularly if such an object intersects with the
conical light zone which results from the intersection of one or
more light beams. Receptacle face 920 is seen, holding two or more
light sources 990. Each light source creates a light beam 910,
which intersects with any other light beams to create a conical
shaped light zone 930.
[0072] Contact Assembly
[0073] The electrical receptacle of the invention includes a
contact assembly, which is adapted and configured to conductively
couple each blade of the plug to a conductor. For this invention,
the electrical state of the contact assembly is determined by the
relays, as the contact assembly is conductively coupled to (a)
relay(s).
[0074] The relay assembly is adapted and configured to conductively
couple each blade contact of the receptacle to the hot and neutral
conductors of an electrical system under the direction of commands
sent from the control circuit. The relay circuitry may be either NO
or NC in function, NO representing a `power upon proper insertion`
control circuitry, and NC representing a `power revoked for
improper insertion` control circuitry. The relay can be a power FET
or other known power control device.
[0075] The electrical receptacle of the invention includes a
control circuit which determines presence of a properly inserted
plug, and may also ensures no activity in the immediate vicinity of
the plug, or other features of the receptacle's environment. The
electrical receptacle of the invention can utilize any combination
of the plug component sensors and any signal analysis method(s). In
general, if one or more control circuits mentioned below are used
and determine an unacceptable condition, any of them may revoke
power to the receptacle.
[0076] The electrical receptacle of the invention may alternatively
include a control circuit which revokes power to a receptacle after
an improper insertion has been detected, subject to reset or
reactivation with a proper insertion.
[0077] Control Logic
[0078] Electrical control which requires substantially simultaneous
detection of two or more plug components virtually eliminates the
possibility of accidental shock or electrocution as a result of
inserting foreign objects.
[0079] A properly inserted plug will present it's standardized
geometry to strategically placed plug component sensors at almost
the same time, that is, `substantially simultaneously.` In order to
use this type of signal analysis method, the invention preferably
has at least two plug component sensors, thereby permitting the
control circuitry to determine if substantially simultaneous plug
component detection has occurred. More specifically, substantially
simultaneous means that the required plug components arrive in the
presence of the individual plug component sensors within a short
period of time; meaning that all plug component sensors present in
a receptacle detected their assigned plug components within a short
period of time. This period of time should be less than 1 s,
preferably less than about 350 ms.
[0080] FIG. 10 shows a electrical schematic suitable for an
embodiment having a pair of blade sensors. Seen in the schematic is
an OR gate 1030, a second OR gate 1070 and a third OR gate 1080.
Also seen is a one shot timer 1050. This circuit receives signals
1020 and 1040 from the blade sensors and ultimately sends a signal
1090 to the relay assembly. If one of the blade sensors detects
insertion, the one shot timer 1050 defines a predetermined period
of time in which the second blade sensor must also detect
insertion. This circuit illustrates the substantially simultaneous
requirements of the invention as pertaining to an embodiment
employing a pair of blade sensors. These blade sensors can be
configured as blade tip sensors, blade aperture sensors or can be
configured to detect other portions of a blade as well.
[0081] FIG. 11 shows a similar electrical schematic, albeit for an
embodiment which also utilizes a face sensor. Seen in the schematic
is an OR gate 1140, a second OR gate 1160 and a third OR gate 1170.
Also seen is a one shot 1150. This circuit receives signals 1110,
1120 and 1130 from the two blade sensors and the face sensor,
respectively, and ultimately sends a signal 1180 to the relay
assembly. If one of the blade sensors detects insertion or the face
sensor detects an impinging plug face, the one shot timer 1050
defines a predetermined period of time in which the remaining
sensors must also detect insertion. This circuit illustrates the
substantially simultaneous requirements of the invention as
pertaining to an embodiment employing a pair of blade sensors and a
face sensor.
[0082] While it is unlikely that two plug blades is inserted
exactly simultaneously, plug design dictates, for example, that
insertion of one blade will follow very closely with insertion of a
second blade. This requirement means it is much less likely that a
person can receive a shock as a result of insertion of foreign
objects into the receptacle. It is unlikely that a person,
especially a child, can insert multiple conducting foreign objects
into the receptacle and activate all of the plug component sensors
at essentially the same time.
[0083] Electrical control may require substantially simultaneous
detection of a blade tip and a blade aperture. Upon the event that
a blade aperture sensor detects an object in it's sensing area, it
must cease to sense that object and a blade tip must be sensed with
a separate plug component sensors within a short period of time.
This period of time should be less than about 1 s, preferably less
than about 300 ms.
[0084] FIG. 12 illustrates an embodiment in which the concept of
substantially simultaneous is merged with that of sequential
timing. This embodiment employs both a blade tip sensor and a blade
aperture sensor. As noted, a single sensor can be configured for
both tasks, or separate sensors can be included. In either case,
the circuit requires a blade aperture-sensor signal 1210 and a
blade tip sensor signal 1220. If the user select jumper 1230 is
left intact, the circuit requires that detection of the blade
aperture occur within a very short period of time after detection
of an inserted blade tip. This feature can be employed to require
insertion only of specially configured plugs. For example, the
blade tip to blade aperture distance can be altered.
[0085] If the user select jumper 1230 is removed, the circuit would
then function in the substantially simultaneous mode previously
discussed. Also seen in the figure are blade aperture sensor one
shot timer 1250 and blade tip sensor one shot timer 1270, along
with 2 OR gates 1280 and 1292. If the user select jumper 1230 is
removed, inverter 1260 becomes meaningless. Also seen is decision
gate 1240 and 4 AND gate 1290. Finally, the circuit provides a
signal 1294 to the unseen relay assembly.
[0086] Plug design dictates that detection of an object in the area
of the blade aperture will closely follow with detection of an
object in the area of the blade tip and an absence of an object in
the area of the blade aperture in the event of a properly inserted
plug. This requirement means it is much less likely that a person
can receive a shock as a result of insertion of foreign objects
into the receptacle. It is unlikely that a person, especially a
child, can insert a conducting foreign objects with a tip geometry
similar to a plug blade.
[0087] Unacceptable Conditions
[0088] Electrical control can require a "stable" lack of motion
within the immediate vicinity of the receptacle, insuring that the
receptacle does not supply power while an moving or temporarily
stationary object is in the immediate vicinity of the outlet. This
virtually eliminates the possibility of accidental shock or
electrocution as a result of inserting foreign objects.
[0089] The control circuit may only allow the relay to supply power
to the contact assembly after any non stationary object is absent
from the area, and has been absent from the area for a
predetermined period of time. Preferably, this time period is less
than 1 s.
[0090] Addition of a motion sensor to prevent the power from
flowing while motion is present, regardless of the state of the
substantially simultaneous plug component detection, virtually
eliminates the possibility of accidental shock caused by contact
with partially inserted conductive plug blades or foreign objects
that provide the significantly simultaneous criteria.
[0091] Electrical control can require a lack of motion within the
immediate vicinity of the receptacle, insuring that the receptacle
does not supply power while an moving object is in the immediate
vicinity of the outlet. This virtually eliminates the possibility
of accidental shock or electrocution as a result of inserting
foreign objects. The control circuit may only allow the relay to
supply power to the contact assembly after any non stationary
object is absent from the area.
[0092] Addition of a motion sensor to prevent the power from
flowing while motion is present, regardless of the state of the
significantly simultaneous plug component detection, virtually
eliminates the possibility of accidental shock caused by contact
with partially inserted conductive plug blades or foreign objects
that provide the significantly simultaneous criteria. This control
method has a faster response than the motion with delay option.
[0093] Electrical control can require an absence of objects within
a defined area in front of the receptacle, insuring that the
receptacle does not supply power while an object is in the
immediate vicinity of the outlet. This virtually eliminates the
possibility of accidental shock or electrocution as a result of
inserting foreign objects.
[0094] FIG. 13 illustrates the circuitry required by a preferred
embodiment in which two blade sensors and a face sensor are used.
This figure is quite similar to FIG. 10, with the exception that
this figure also shows relay assembly 1390. Otherwise, the figure
shows blade sensor signals 1310 and 1320, along with face sensor
signal 1330. One shot timer 1350 provides a predetermined period of
time in which the remaining sensors must report detection after
initial detection by one of the three sensors.
[0095] FIG. 14 illustrates the circuitry required by a preferred
embodiment in which two blade sensors, a face sensor and a motion
detector are all used. This figure is similar to FIG. 10, with the
exception of the motion detector signal 1440 and the relay assembly
1496. Also unique to this circuit are the inverted 1480 and the 2
AND gate 1492. The 2 AND gate 1492 requires that the motion
detector report a lack of motion near the receptacle while the rest
of the circuit also reports a properly inserted plug. This prevents
accidental shock caused by improperly grasping a partially inserted
plug. Otherwise, the figure shows blade sensor signals 1410 and
1420, along with face sensor signal 1430. One shot timer 1460
provides a predetermined period of time in which the remaining
sensors must report detection after initial detection by one of the
other sensors.
[0096] FIG. 15 illustrates the circuitry required by a preferred
embodiment in which two blade tip sensors are used in conjunction
with two blade aperture sensors in a user-selected sequential
insertion detection mode. This portion of the circuit is quite
similar to FIG. 12, except that it is repeated for each blade.
Satisfactory sequential detection of blade tip and blade aperture
(for each blade) signals to the remaining circuit that both blades
have been properly inserted. The final portion of the circuit,
which is quite similar to FIG. 14, requires that both blades be
properly inserted and the plug face be detected within a
predetermined period of time. The circuit also requires that there
be no motion in the vicinity of the receptacle.
[0097] The first portion of the circuit receives blade tip sensor
signal 1510 and blade aperture sensor signal 1520. If the user
select jumper 1530 is left intact, the circuit requires that
detection of the blade aperture occur within a very short period of
time after detection of an inserted blade tip. This feature can be
employed to require insertion only of specially configured plugs.
For example, the blade tip to blade aperture distance can be
altered.
[0098] If the user select jumper 1530 is removed, the circuit would
then function in the substantially simultaneous mode previously
discussed. Also seen in the figure are blade aperture sensor one
shot timer 1550 and blade tip sensor one shot timer 1570, along
with 2 OR gates 1580 and 1592. If the user select jumper 1530 is
removed, inverter 1560 becomes meaningless. Also seen is decision
gate 1540 and 4 AND gate 1590. Finally, a signal 1594 is provided
to the third portion of the circuit.
[0099] The second portion of the circuit is very similar to the
first. Blade aperture sensor signals 1512 and 1522 are provided to
the circuit. Seen in the figure are one shot timers 1552 and 1572,
along with inverter 1562. OR gates 1582 and 1592 are also present,
as are decision gate 1542 and 4 AND gate 1593. Finally, this
portion of the circuit provides a signal 1595 to the third portion
of the circuit.
[0100] The third portion of the figure is quite similar to FIG. 14,
which is similar to FIG. 10, with the exception of the motion
detector signal 1501 and the relay assembly 1509. Also unique to
this circuit are the inverter 1506 and the 2 AND gate 1508. The 2
AND gate 1508 requires that the motion detector report a lack of
motion near the receptacle while the rest of the circuit also
reports a properly inserted plug. This prevents accidental shock
caused by improperly grasping a partially inserted plug. One shot
timer 1504 provides a predetermined period of time in which the
remaining sensors must report detection after initial detection by
one of the other sensors.. Blade sensor inputs 1594 and 1595 are
provided from the earlier portions of the circuit. Face sensor
signal 1502 is also present.
[0101] FIG. 16 illustrates a typical adaptive receptacle according
to the invention. Seen is a receptacle 1600, with a typical body
1680. Across the front of the receptacle (as installed), receptacle
faces 1605 are seen, each bearing blade receptacle apertures 1602
and 1604, as well as ground prong receptacle aperture 1606. Other
typical features include mounting lugs 1690. The figure also
illustrates the novel combinations of sensors and circuitry which
make up the invention. Shown between blade receptacle apertures
1602 and 1604 are face sensors 1630. Motion or proximity sensor
1620 is shown positioned between receptacle faces 1605. Along the
side of the receptacle 1600 are seen blade sensors 1640 and ground
prong sensors 1650.
[0102] The above specification and examples provide a complete
description of the manufacture and use of the composition of the
invention. Since many embodiments of the invention can be made
without departing from the spirit and scope of the invention, the
invention resides in the claims hereinafter appended.
* * * * *