CA 02467023 2009-01-21
Central Vacuum Cleaning System Motor Control Mounting Post, Mounting
Configuration, and
Mounting Methods
FIELD OF THE INVENTION
The invention relates to motor control circuit mountings. More particularly,
it relates to mountings used in
association with illuminated information indicators.
SACKGROUND OF T>:iE INVENTION
Many modern buildings have central vacuum cleaning systems. These systems have
a suction motor to
create a vacuum in a series of pipes tlirough the building. A user of the
system connects a flexible hose to
one of the pipes. The hose has a handle for the operator to grasp. The handle
is further connected to one or
more cleaning accessories.
The motor is housed in a motor housing that typically forms part of a
ca,nister. The canister also has a
receptacle portion for receiving dust and other particles picked up through
the cleaning accessories and
traaasported by the vaeuum through the hose and pipes.
The canister is usually plaeed in a central location that is easily acceSsible
for emptying the receptacle. The
motor is typically powered by line voltage that is controlled by a motor
control circuit in the motor
housing.
Low voltage wires typically run beside, or form part of, the pipes and hose
between the canister and the
handle. This permits the operator to control the motor by sending low voltage
signals from the handle to
the motor control circuit. In order to receive the low voltage signals, an
opening is provided in the motor
housing through which the low voltage wires can be connected to the motor
control circuit.
Ixutially, the motor control circuit was mounted outside the n,otor housing
and the low voltage wires were
fed into the motor housing through the opening. In some systems, a low voltage
connector was provided at
the opening, the low voltage wires from the building were connected to the
connector on one side, and the
connector was connected by further wires to the motor control circuit.
The inventor of the current invention created a mounting post that
incorporates a low voltage
connector and is rigidly connected to a circuit board of the motor control
circuit. The mounting
post holds the circuit board and its components from undesired contact with
anything else in the
motor housing, including the housing itself and the motor, and in generally
fixed relationship with
the motor housing. This simplifies the assembly of the motor control circuit
in the motor housing.
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When the mounting post is the only means of mounting the motor control
circuit, the control circuit
may be permitted to turn about the mounting post with respect to the motor
housing. It is known to
inhibit substantially all movement between the circuit board and the motor
housing by securing the
circuit board at a second position: namely, at the circuit breaker.
It is known to insert an LED with a square configuration in a cut-out in the
mounting post; so that,
the LED protrudes through the opening. The selection of readily available LEDs
for the square
configuration is limited in power and colour. The LED provides an illuminated
information
indicator of proper operation of the vacuum source.
SUMMARY OF THE INVENTION
In a first aspect the invention provides a mounting post for receiving light
from a light source on a
printed circuit board in a motor control circuit for use in a motor control
housing of a central
vacuum cleaning system. The mounting post has a first securing section for
securing the mounting
post to the motor control housing such that a portion of the mounting post is
accessible from outside
the motor control housing. It also has a light guide for guiding light from
the light source through
the mounting post for emission from the mounting post outside the motor
control housing. It further
has a second securing section for securing the mounting post to the printed
circuit board such that
the light guide receives light from the light source. It also has a stand-off
section between the first
securing section and the second securing section for holding the motor control
circuit from
undesired contact.
The mounting post may have a low voltage connection section for connection to
one or more low
voltage conductors. The low voltage connection section would form part of that
portion of the
mounting post that is accessible from outside the motor control housing. The
mounting post may be
clear. The mounting post may be made from polycarbonate resin. The mounting
post may guide
light through a structural element of the mounting post.
The mounting post may have an elongate body within which light is guided. The
standoff section
may have a shoulder at one end of the elongate body, the shoulder, at least in
part, being wider than
an opening in the motor housing to prevent the mounting post from fitting
through the opening.
The first securing section may have a threaded portion extending from the
shoulder, the threaded
portion being smaller than the opening in the motor housing. It may also have
the shoulder, and a
nut compatible with threads of the threaded portion. The nut would be, at
least in part, greater than
the opening in the motor housing. The mounting post would be secured to the
motor control
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CA 02467023 2004-05-12
housing by placing the threaded portion through the opening from inside the
motor control housing
and tightening the nut onto the threaded portion from outside the motor
control housing.
In a second aspect, the invention provides a motor control circuit for use in
a central vacuum
cleaning system. The motor control circuit has a printed circuit board with a
light source mounted to
the printed circuit board, and the mounting post of the first aspect.
In a third aspect the invention provides a central vacuum cleaning system
having a motor housing
housing a motor. It also has a motor control circuit for controlling the
motor, the motor control
circuit having a printed circuit board with a light source mounted to the
printed circuit board. It
further has the mounting post of the first aspect.
In a fourth aspect the invention provides a central vacuum cleaning system
canister. The canister
has a motor housing housing a motor. It also has a motor control circuit for
controlling the motor,
the motor control circuit having a printed circuit board with a light source
mounted to the printed
circuit board. It further has the mounting post of the first aspect.
In a fifth aspect the invention provides a method of providing central vacuum
cleaning system
information messages from a motor control circuit of the central vacuum
cleaning system to a user.
The method affixes a light source to a motor control circuit printed circuit
board. It secures the
mounting post of the first aspect to the printed circuit board over the light
source. It illuminates the
light source to provide a message to a user. It guides light from the light
source through the
mounting post to outside the motor control housing.
The details of the preferred embodiment of these and other aspects of the
invention are set out
further below.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention and to show more clearly
how it may be carried
into effect, reference will now be made, by way of example, to the
accompanying drawings which
show the preferred embodiment of the present invention and in which:
FIG. 1 is a cross-section of a building with a central vacuum cleaning system
in accordance with the
preferred embodiment of the present invention;
FIG. 2 is a cut-away perspective view of a canister used in the system of FIG.
1, showing a motor
control circuit with a mounting post in accordance with the preferred
embodiment of the present
invention;
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CA 02467023 2004-05-12
FIG. 3 is a cross- section of the motor control circuit, the mounting post and
a portion of the canister
of FIG. 2;
FIG. 4 is an exploded perspective view of the mounting post of FIG. 2;
FIG. 5 is an exploded perspective view of the mounting post and light source
of FIG. 2, including a
retaining nut;
FIG. 6 is a perspective view of the mounting post of FIG. 2 showing possible
light guided paths;
FIG. 7 is an exploded perspective view of the mounting post of FIG. 2 and
multiple light sources;
and
FIG. 8 is an exploded perspective view of an alternative mounting post and nut
utilizing an optical
fibre and, alternatively, a plurality of optical fibres.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, a central vacuum cleaning system (indicated generally at
1) is installed in a
building 3. The building 3 is shown as a residence; however, the system 1
could be installed in
other buildings, such as commercial or industrial buildings.
The system 1 has a vacuum source 5 in a central location. The source 5 is
connected through pipes
7 or other conduits in walls, floors or ceilings of the building 3.
Alternatively, the pipes 7 may be
exposed. The pipes 7 terminate at valves 9 to which a flexible hose 11 may be
connected. The hose
11 terminates in a handle 13 that is held by an operator 15. Various cleaning
attachments, such as a
carpet brush 16, are connected to the handle 13.
Running beside, or as part of, the pipes 7 and the hose 11 is a pair of low
voltage wires 17 that
provide control signals, such as ON/OFF, from the operator 15 through a switch
18 in the handle 13.
More sophisticated systems 1 may utilize the low voltage wires 17 for many
other purposes, such as
duplex communications that allow the receipt of information at the handle 13.
Such information
could be used to drive LEDs or other display means 19 for communication with
the operator 15.
When the operator 15 turns on the system 1, dirt is drawn by a vacuum created
by the vacuum
source 6 through the attachment 16, handle 13, hose 11, and pipes 7.
Referring to FIG. 2, the vacuum source 5 has a motor, not shown, within a
motor hotsing 21.
Extending from the motor housing 21 is, typically, a receptacle 23 for
receiving the dirt. Also
within the motor housing 21 is a motor control circuit 25. The motor control
circuit 25 extends
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CA 02467023 2004-05-12
through the housing 21 and terminates in a low voltage connector 27. The
connector 27 receives a
corresponding connector 29 of the low voltage wires 17. In the preferred
embodiment, the motor
housing 21 also acts as a motor control housing 21. Accordingly, the motor
housing 21 will be
referred to as a motor control housing herein, unless the context requires
otherwise. It is to be
understood that the motor housing and motor control housing could be separate
from one another.
It is to be noted that low voltage wires 17 may be replaced by wireless
transmitters and receivers,
not shown, at least one of which may be connected, directly or indirectly, to
the connector 27 to
provide the low voltage signals that would otherwise be provided through low
voltage wires 17.
Alternatively, a transmitter and/or receiver could be placed inside the motor
control housing 21 as
part of the motor control circuit 25.
Referring to FIGS. 2 through 4, the motor control circuit 25 is typically laid
out on a printed circuit
board 33 that has a microprocessor 34, relay 35 and a line to low voltage
transformer 37. The
switch 18 (FIG. 1) in the handle 13 is typically a momentary switch 18. When
the switch 18 is
actuated a control signal is sent to the microprocessor 34 that causes a
change of state of the relay 35
to connect or disconnect power to the motor.
The connector 27 has conductors 39a, 39b for conducting electricity between
the printed circuit
board 33 and the low voltage wires 17. The conductors 39 are surrounded by a
housing 41, except
at opposing first and second housing ends 43, 45. The conductors 39 are solid
conductors 39 that
extend as a prong 47 at one end 49a, 49b for connection to a low voltage wire
17. At an opposing
end 5 la, 5 lb each conductor 39 terminates in pins 52ai, 52aii, 52bi, 52bii
that extend beyond the
second end 45 of the housing 41 for insertion into through holes 53 in the
printed circuit board 33.
The conductors 39 are soldered at the underside 54 of the printed circuit
board 33. This secures the
conductors 39 and, thus, the housing 41 to the board 33 and connects them to
the motor control
circuit 25. The housing 41, conductors 39, pins 52 provide a securing section
A for physically
securing the housing 41 to the printed circuit board 33.
The principles described herein are not limited to a securing section A using
pins 52. For example,
the housing 41 could have pins, not shown, extending from second housing end
45 for insertion
through holes, not shown, in the printed circuit board 33. The pins would be
of the same material as
the housing 41. The housing 41 is then secured to the printed circuit board 33
by heat welding the
pins.
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CA 02467023 2004-05-12
As shown, the housing 41 is recessed about the end 49a, 49b to securely
receive dual female -
configured connector 29. The principles described herein are not limited to
the configuration shown
for the housing 41 and prongs 47. For example, it is not required that the
housing 41 be recessed.
The prongs 47 could extend beyond the housing 41. As another alternative, the
prongs 47 could be
replaced by a female-configured connector 27 for receipt of a male-configured
connector 29. Also,
the conductors 39 need not be flat plate conductors 39. For example, the
prongs 47 could be
connected to wires that extend the length of the housing 41 for insertion into
through holes 53 or an
alternative means for connection to the printed circuit board.
The connector 27 forms a low voltage connection section B for electrical
connection of the low
voltage wires 17 or other low voltage conductors to the motor control circuit
25.
The housing 41 has an elongate body 55 that terminates in a shoulder 56. The
housing 41 has a
cylindrical threaded portion 57 extending above the shoulder 56. The
cylindrical threaded portion
57 terminates in a face 58 to permit access to the prongs 47. The connector 27
is recessed into the
cylindrical threaded portion 57 through the face 58. The cylindrical threaded
portion 57 is
dimensioned to fit through a circular opening 59 in the motor housing 21 in
order to receive a nut
60a.
The nut 60a is threaded onto the threaded portion 57. The nut 60a and shoulder
56 are dimensioned
to be sufficiently greater than the diameter of the opening 59 to secure the
motor control circuit 25 to
the motor housing 21 when the nut 60a is tightened. The shoulder 56 and
threads 57 form a
securing section C for securing the motor control circuit 25 to the motor
housing 21. Other
components of the motor control circuit 25, such as circuit breaker 60b, may
also perform the
securing function to prevent rotation of the motor control circuit 25 with
respect to the motor
housing 21.
It is to be noted that the opening 59 need not be circular. In fact, a nort-
circular opening 59 might
assist in preventing rotation of the motor control circuit 25, where a second
securing point (such as
circuit breaker 60b) is not used. The profile of the securing section C at the
opening 59 could be
changed to match the shape of the opening 59.
Preferably, the face 58 is flush with top surface 60c of nut 60a for aesthetic
reasons. In the preferred
embodiment, the face 58 is flat, except about the connectors 27. This is a
design choice. The face
58 needs to be configured to allow access to the prongs 47 as discussed above
(where a low voltage
connection is used) and to be visible to the user where light is emitted from
the face 58.
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CA 02467023 2004-05-12
Again, the principles described herein are not limited to the particular form
of securing section C
described herein. The securing section C could take many forms. For example,
the housing 41
could be secured to the motor housing 21 using a snap-in fitting.
The body 55 is sufficiently long to electrically isolate components on the
circuit board 33 from the
motor housing 21, to provide air circulation between the printed circuit board
33 and the motor
housing 21, and to meet other regulatory, safety and design requirements.
The body 55 and shoulder 56 form a stand-off section D between the motor
control circuit 25 and
the motor control housing 21. Again, the principles described herein are not
limited to a stand-off
section D in the particular form shown in the Figs. For example, the shoulder
56 does not need to
extend about the entire circumference of the housing 41.
For ease of manufacture and assembly, the housing 41 is made in two
longitudinal pieces 61a, 61b.
One piece 61a has a cross-member 62 that splits the body 55 into two
longitudinal cavities 63a, 63b.
The cavities 63 have respective opposing grooves 64. One conductor 39 fits
into the groove 64 of
each cavity 63. The conductors 39 have notches 65, and the housing pieces have
corresponding
bosses 67 for retaining the conductors 39 when the pieces 61 are combined to
form the housing 41.
A tab 69 with a hook 70 extends from the cross-member 62 for insertion into an
opposing hole 71 in
the piece 61b. The lble 71 is slightly offset from the tab 69. The tab 69 is
sprung as it is inserted
into the hole 71 and snaps back to engage the hook 70 on the exterior of the
piece 61b. This secures
the two pieces 61 together to form the housing 41.
The housing 41 has a hollow 73 into the body 55 for receiving a light source
75 on the printed
circuit board 33. The light source 75 shown is an LED 75. The housing 41 is
made from a
translucent, preferably transparent, material that acts as a light guide E
(FIG. 4) to guide light from
the light source 75 through the housing 41 to the face 58.
Again, the principles described herein are not limited to the particular
configuration of housing 41
illustrated in the FIGS. For example, the housing 41 could be made in a single
piece moulded about
conductors 39.
The securing section A, connection section B, securing section C, stand-off
section D and light
guide E form a mounting post 76. If a wireless transmitter and/or receiver is
in the motor control
housing 21 then there may be no need for the low voltage connection section B;
however, the
mounting post 76 will continue to be useful in order to guide light from the
source 75 to the face 58
for the communication of information to a user.
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CA 02467023 2004-05-12
Although the preferred embodiment is being described with reference to a motor
control circuit 25
for mounting inside a motor housing 21, as mentioned previously, the circuit
25 need not be
mounted inside the motor housing 21. For example, the circuit 25 could be
mounted within a
controlbox, not shown, outside the housing 21 with wires fed back into the
housing 21 for operation
of the motor. This might be done for additional isolation of the control
circuit 25 from the motor.
For example, it might be helpful to avoid electromagnetic interference from
the motor. The control
box would be an alternate form of motor control housing 21. As mentioned
previously, for this
reason, the motor housing 21 is being referred to as a motor control housing
21 in this description,
unless the context requires otherwise.
Referring to FIG. 6, light enters the cross-member 62 above the hollow 73 and
is guided to the face
58 and exits through the face 58, as shown at arrows J. It is also possible
that light can enter through
the interior wall 79 of the cavities 63 and be guided through the interior
wall 79 to the face, as
shown at arrows K. Light may also be guided within the cavities 63 to the face
58, as shown by
arrows L. Conductors 39 have been omitted from FIG. 6 for clarity. The
conductors 39 may change
the path L for some light, as light is reflected from the conductors 39.
How much light is captured by the various potential guide paths, how much
light is lost in those
paths (for example, by escaping as it meets an interface, or by absorption),
and how much light is
emitted at the face 58 will depend on the orientation of the light source and
the paths, the material or
materials of the light guide, and the intensity and wavelength of the light
source 75, among other
factors. Although preferred specifications for these factors are shown and/or
described, others may
be chosen depending on the particular circumstances of a given application.
In the preferred embodiment, very limited amounts of light are guided through
paths K and L to be
emitted at the face 58. As sufficient light is guided through path J, the
other paths K and L were not
optimized. For example, path K, could be shaped for orientation of a light
entrance towards the light
source 75 to better capture light.
In the preferred embodiment, a clear, uncoloured polycarbonate resin is used
to create the housing
41 as it is rigid, long lasting and inexpensive, and has acceptable optical
properties. Many
alternative materials may be used to fulfil the principles described herein.
Thus, the mounting post 76 utilizes structural elements of the post 76, i.e.
elements that are part of
the structural integrity of the post 76, such as the cross-member 62 and wall
79. We will see later
that other non-structural elements of the post 76 may be used to guide the
light.
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CA 02467023 2004-05-12
As the housing 41 has a flexible design, it can be adapted to work with
different light sources 75.
LEDs are a preferred choice as LEDs are long lasting, small, inexpensive, and
low power devices.
Higher power LEDs, LEDs of different colours, mul&colour LEDs, and LEDs of
different shapes
and sizes may all be used. Standard LED packages such as a T- 1 or T-13/a can
be used. These tend
to be the least expensive. This allows for LEDs of more than 3000 mcd, for
example 3200 mcd and
4500 mcd in green. These are examples only and many other sizes and
configurations can be used.
For example, a multrcolour LED could be used to provide many possible
signalling combinations,
such as a red/yellow LED that can provide red solid, red flashing, yellow
solid, yellow flashing,
orange solid, and orange flashing. Also, single colour LEDs can be chosen from
a wide variety of
colours, including green, yellow, red, white and blue, among others.
The messages provided to the user by the LEDs might include, for example, 1)
informing the user
that electrical power is present and the system 1 has no apparent problems, 2)
the dust receptacle 23
is full and should be emptied, 3) service to the system I is needed, 4)
service to the motor is
required, i.e.. change the brus hes, 6) the system 1 is not functioning
properly, there is some type of
blockage in the pipes 7, in the flexible hose 11 or the filter medium is
clogged. These are samples of
the types of messages that might be conveyed to the user. Many other messages
could be conveyed
as desired by the designers of the motor control circuit 25.
Referring to FIG. 7, an alternative mounting post 101 has a hollow 103
sufficient to cover multiple
LED light sources 105a, 105b, 105c. This allows for multiple colours, while
using inexpensive
single colour LEDs 105. The particular shape of the housing 41 will be a
design choice to allow
sufficient light to be captured from each of the LEDs 105 for guiding to the
face 58. For example, in
many cases it will be sufficient to simply have a clear housing 41 placed over
and in sufficient
proximity to the light source 75 to guide incident light to the face 58.
Although non-incident light
from the light source 75 is wasted, extra light inside the motor housing 21
will generally have no
detrimental result.
Referring to FIG. 8, an alternate mounting post 201 utilizes an optical fibre
203 to guide light from a
light source, not shown. An alternative mounting post 201 could utilize
braided optical fibre 303 to
guide light from the light source. In the post 201, the fibres 203, 303 are
non-structural elements
that are used to guide the light.
The embodiments shown in FIGS. 5 and 7 could utilize a housing 41 that is non-
translucent except
to allow light to be guided through the face 58. In this case the face 58 may
be translucent, or the
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fibres 203, 303 could extend through and flush with the face 58 at aperture
307. As a further
alternative, an opening, such as aperture 307, could allow light guided inside
the mounting post 76
to exit the aperture 307 and be viewed by a user. The aperture 307 could be
enclosed by a
translucent cover, not shown, or left unenclosed.
Similarly, a housing 41 could have one or more portions (for example, only the
cross-member 62)
that are translucent to permit light to be guided from a light source on the
printed circuit board 33 to
the face 58 through the translucent sections of the housing 41.
It will be understood by those skilled in the art that this description is
made with reference to the
preferred embodiment and that it is possible to make other embodiments
employing the principles of
the invention which fall within its spirit and scope as defined by the
following claims.
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