Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02322235 2000-10-04
This invention relates to a support for constructing an electrical or
electronic circuit, and more
particularly relates to a compact modular support and casing used for the
construction of an electrical
or electronic circuit in a developmental stage.
In constructing an electrical or electronic circuit particularly for
experimental or
developmental purposes, it is often necessary to make numerous changes of the
electrical components
in order to obtain the desired circuit. Heretofore, in constructing an
electrical or electronic circuit,
the electrical components are axed to a support such as a printed circuit
board by soldering their
leads and the connection wiring to metal tracings provided on the printed
circuit board. When
changes in the circuit are required, it is necessary to remove or replace the
selected electrical
components from the printed circuit board by de-soldering them therefrom and
then soldering the
new replacement components thereto. Such operation is awkward and dii~cult and
more often
frustrating to carry out particularly for a complex circuit having numerous
electrical components and
wiring interconnecting to various points in the circuit.
The above drawback of using a printed circuit board has been alleviated with
the use of a
circuit support commonly referred to as a "breadboard" which consists of a
rectangular plastic board
having a plurality ofparallel rows and columns ofbus bars provided at its
bottom surface. A plurality
of through openings are formed in the board such that electrical components
may be interconnected
by merely inserting their leads through the openings for connecting to
selected bus bars. However,
the circuit breadboard is not provided with any power supply and bare live
connection terminals are
normally directly mounted at one of its edge portion for connection to
external power supply source
or to other circuit testing equipment. Therefore, the circuit constructed on
the breadboard per se is
not self contained and self operative. Moreover, in order to preserve the
circuit, the breadboard with
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the electrical components mounted thereon must be placed within a suitable
enclosure. The enclosure
must then be modified to accept auxiliary components such as switches,
connectors etc., for operating
the circuit. The entire procedure is tedious and the completed unit is rather
untidy and not well
protected such that it may be easily damaged.
Another problem with either printed circuit board or circuit breadboard
support is the
difficulty of providing supports for auxiliary components such as toggle
switches, connection ports,
and display etc., for the circuit. There is no provision for mounting these
components directly on the
board in order that connection to such auxiliary components may be made during
the construction
ofthe circuit. Therefore, openings must be made in the side and top panels
ofthe protective enclosure
which is commonly a plastic box, for mounting such auxiliary components. These
openings are
commonly formed by cutting or sawing the side and top panels of the plastic
box. Such operation is
often difficult and very frustrating to carry out as the panels of the plastic
box particularly the side
panels would often break in the cutting and sawing operations; and even if the
cutting and sawing
operations are successfixl, the openings thus formed are rather unkempt.
Moreover, the operation of the circuit thus constructed must be tested with
various complex
and expensive testing equipment and electrical supply must be provided by
external complex
equipment which are normally designed for general testing purposes. Such
general purpose testing
equipment are expensive and bulky in size and they are usually not a~'ordable
for a circuit developer
and particularly for a student learning to develop an electrical or electronic
circuit.
It is a principal object ofthe present invention to provide a compact modular
support in which
electrical components may be easily and quickly installed or replaced.
It is another object of the present invention to provide a modular support
having
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interchangeable side plates for mounting auxiliary components for easy
building of an electrical or
electronic circuit..
It is yet another object of the present invention to provide a cover
engageable with the
interchangeable side plates to form a secure protective enclosure for the
circuit.
It is still another object of the present invention to provide a modular
support in which various
selective compact testing module may be interchangeably mounted therein for
testing the operation
of the circuit constructed.
It is another object of the present invention to provide a modular support
having its own
alternate power supply.
It is another object of the present invention to provide a modular support
suitable for
constructing development model of digital and analog circuits.
Briefly, the modular support for the present invention for constructing an
electrical circuit
comprises of a base having a substantially rectangular depression formed in a
top surface therein and
having a substantially rectangular bottom interior compartment. A plurality of
electrical contacts are
formed on top of the bottom panel of the depression. A circuit breadboard
member is mounted in the
depression. The circuit breadboard member has a plurality of conductive bus
bars formed at its
underside. The conductive bus bars are in contact with predetermined ones of
the electrical contacts.
The circuit breadboard has a plurality of connection openings formed therein
and they are adapted
for receiving conductive leads of electrical components to be inserted
therethrough for connecting
to selected ones of the bus bars. Electrical components may be inserted
through these openings for
connecting to selected ones of the bus bars. A metal heat sink member is
located in the bottom
interior compartment and it is positioned below the circuit breadboard member.
The bottom interior
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compartment is covered by a bottom cover plate which has a plurality of
ventilation openings formed
therein. The ventilation openings are located below the heat sink member.
Figure 1 is a perspective exploded top elevation view of the support according
to the present
invention.
Figure 2 is a cross sectional side view of the support along section line II-
II in Figure 1.
Figure 3 is a bottom elevation view of the support with the bottom cover plate
removed.
Figure 4 is a bottom elevation view of the bottom cover plate.
Figure 5 is a top elevation view of the second embodiment of the support
according to the
present invention having provision for interchangeable testing modules to be
mounted therein.
Figure 6 is a top elevation view ofthe second embodiment ofthe support with
the breadboard
and testing module mounted therein.
Figure 7 is a bottom elevation view of the second embodiment of the support.
Figure 8 is a perspective top elevation of the embodiment having mounting
slots formed in
the longitudinal side edge portions of the base with a side plate removably
mounted thereon.
1 S Figure 9 is a cross sectional side elevation view of the U-shaped cover
along section line IX-
IX in Figure 8.
Figure 10 is a cross sectional front elevation view of the U-shaped cover
along section line
X-X in Figure 8.
Figure 11 is an isolated top elevation view of the longitudinal side edge
portion of the base
with a side plate slidably mounted thereon.
Figure 12 is a cross sectional side elevation view along cross section line
XII-XII in Figure
11
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Figure 13 is a perspective front elevation view of a side plate with a pre-
formed opening for
mounting a switch.
Figure 14 is a perspective front elevation view of the side plate of Figure 13
with the switch
mounted thereon.
Figure 15 is a perspective side elevation of Figure 14.
Figure 16 is a perspective front elevation view of the side plate having a pre-
formed opening
for mounting a round shape auxiliary electrical component such as an indicator
light.
Figure 17 is a perspective front elevation view of another side plate having a
pre-formed
opening for mounting a mufti-pin connector such as a power source connector.
With reference to the drawings wherein like reference numerals designate
corresponding parts
in the several views, the support of the present invention has a substantially
rectangular base 10
having a top rectangular depression 11 therein. The depression 11 is bounded
by two upstanding
mutually parallel short side edge portions 12 and 13, and two upstanding
mutually parallel
longitudinal side edge portions 14 and 15 and a bottom panel 16 so that the
depression 11 has upright
short side walls 17 and 18 and upright longitudinal side walls 19 and 20. The
base 10 has a bottom
interior compartment 21 which may be enclosed with a bottom cover plate 22. A
rectangular auxiliary
compartment 23 is located in the base 10 for housing batteries operative for
providing alternate
power supply for the circuit constructed on the base.
A rectangular metal plate 24 is located in the interior compartment 21 to
serve as a heat sink
for dissipating the heat generated by the electrical components in the
operation of the circuit, and a
printed circuit board 25 for mounting various control electrical components
are also located in the
interior compartment 21. Control switches 26 and external electrical power
connection receptacle 27
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may be mounted directly to one of the upstanding edge portion such as edge
portion 12 as shown in
Figure 1, for connecting to an external power supply source.
A plurality ofventilation openings 28 are formed in the bottom cover plate 22.
The ventilation
openings 28 are located directly below the heat sink metal plate 24 to
facilitate the heat of the heat
sink to escape from the interior compartment 21. These ventilation openings 28
may be in the form
of louvers or elongated slots having a zigzag channel as best shown in Figure
2 to prevent outside
object from falling easily into the interior compartment 21 when the support
is placed up side down.
It can be appreciated by those skilled in the art that the ventilation
openings may be in other shape
such as circular to serve the same purpose.
Integral support legs 29 are formed adjacent to two opposite corners of the
cover plate 22
as best shown in Figure 4 and two additional support legs 30 and 31 may also
be provided adjacent
to the other two corners of the cover plate 22. The heat sink metal plate 24
may be mounted on the
bottom cover plate 22 by two bolts 32 and 33. Two pairs of spring electrical
contacts 34, 35 and 36,
37 are provided on the bottom panel 16 of the depression 11. These electrical
contacts 34 through
37 are connected to the power supply.
A rectangular circuit mounting board commonly referred to as a "breadboard" 38
is mounted
in the depression 11 such as by securing bolts 39, 40 and 41 extending through
the bottom panel 16
ofthe depression 11 as best shown in Figure 2. The breadboard 38 has a
plurality ofparallel rows and
column of conductive bus bars provided at its underside and it has a plurality
of rows and columns
of through openings formed therein. Connectors are located in the through
openings and extending
upwards from the corresponding rows and columns of bus bars such that the
leads of electrical
components and wiring may be inserted into the openings to connect with
selected bus bars through
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the connectors to form the desired electrical circuit. Selected bus bars of
the breadboard 38 will
contact predetermined ones ofthe spring electrical contacts 34, 35, 36 and 37
when the breadboard
38 is located in the depression 11. The breadboard 38 normally has two upper
rows of openings 43
and 44, and two lower rows of openings 45 and 46 designated for connection to
the electrical power
supplies; the bus bars associated with these openings are those in contact
with the spring electrical
contacts 34, 35, 36 and 37 located on the bottom panel of the depression 11.
Normally for electronic
circuits the power supplies are + 5 volts and +12 volts.
An upper cover 47 is provided for covering over the base 10 to protect the
circuit constructed
on the breadboard 38. Cut outs 48 and 49 are formed in the side wall of the
cover 47 to
accommodate the switch 26 and external power supply connector 27 respectively.
Additional cut out
such as cut out 50 may be provided to accommodate additional components
mounted at the edge
portion of the base 10. The top panel of the cover 47 has a flat upper surface
51. Openings may be
formed in the top panel for mounting selected electrical components such as a
display, indicator lights
and timers etc. Four L-shaped abutments 52, 53, 54 and 55 are formed adjacent
to four corners of
the top surface so that a template may be conveniently and precisely placed on
the top panel of the
cover, guided by the abutments, for forming the required openings accurately
for mounting such
electrical components. It can be appreciated that the unit thus constructed is
sturdy, self contained
and self operative.
A second rectangular depression 56 may be formed in a larger base 10 as best
shown in Figure
5 to facilitate a selected testing module 57 to be interchangeably mounted in
the base 10. Also,
breadboards having various selected configurations may be mounted in the
depression 11 having
additional pairs of spring electrical contacts provided at its bottom panel to
provide the electrical
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supplies for operating the circuit. Three pairs of such spring electrical
contacts are shown for
illustration purposes in Figure 5 to provide any additional electrical supply
voltage such as +9 volts
for operating the circuit constructed on the breadboard. Power supply voltages
of+ 5 volts, ~ 9 volts,
and ~ 12 volts are the common operating voltages for electronic analog and
digital circuits.
Accordingly, no complex power supply is required, and the power supply may be
provided by a
simple wall receptacle direct plug-in power supply transformer connected to
the support through the
power supply connector 27. An alternate power supply may also be provided with
batteries located
in the battery compartment 23.
Selected relatively simple testing modules designed for performing various
testing functions
may be interchangeably mounted in the depression 56 to perform the particular
testings required.
Such testing modules may be provided with much less costs and yet much more
convenient to use
than the common expensive mufti-function complex testing equipment which are
designed to perform
numerous testing operations many of which may not be required for the
electrical or electronic circuit
concerned.
1 S Two pivotal spring latch arrangements 58 and 59 are provided on the two
sides ofthe second
depression 56 so that the testing module 57 may be inserted into the
depression 56 with a snap action
to be held in place securely by the spring latch arrangements 58 and 59, and
it may be removed from
the depression 56 by simply depressing the spring latch arrangements 58 and 59
downward with a
sideway pivotal movement to disengage and to remove the testing module 57 from
the depression
56. Electrical contact strips 60 are provided on the side wall of the
depression 56 and associated
electrical contact strips are provided on the side wall of the testing module
so that the contact strips
and associated contact strips will engage with one another when the testing
module is mounted within
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the depression 56 to provide the operating electrical supply and electrical
connection to the circuit.
The terminal block 61 of the contact strips 60 is located in the interior
compartment 21 as best shown
in Figure 7; and the terminal block 62 of the spring contacts for the
breadboard is also located in the
interior compartment for connection to the power supply.
The second depression 56 also serves as a convenient provision for adding more
breadboards
in the support, if required.
Hinges 63 and 64 may be provided on an edge of the base 10 for the top cover
51 to be
removably mounted thereto; and a latch 65 may be provided on the edge opposite
to the hinges 63
and 64 together with an associated latch provided on the top cover 51 so that
the latch and associated
latch are operative to lock the top cover 51 in the closed position so as to
provide a completely
secure enclosure for the circuit.
As shown in Figure 8, an elongated slot 66 having an L-shaped cross section is
formed in the
longitudinal side edge portion 15 of the base 10 and a second elongated slot
67 is also formed on an
extension peripheral rim around the lower edge portion of the base 10 and
located juxtaposed to the
outer side wall of the edge portion 15. Both elongated slot 66 and second
elongated slot 67 extend
throughout the entire length of the base 10 and are opened at both ends
therein so that a plurality of
side plates 68 may be slidably mounted to the base 10 by sliding sideways
through the opened ends
of the slots 66 and 67. Each side plate 68 has a front plate portion 69 and an
integral rear plate
portion 70. The front plate portion 69 is shorter in vertical length than the
rear plate portion 70 such
that a short top edge portion 71 and a short bottom edge portion 72 extend
beyond the corresponding
top edge and bottom edge respectively of the front plate portion 69. Also, a
short vertical side edge
portion 73 ofthe front plate portion 69 extends outwards beyond the
corresponding vertical side edge
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portion of the rear plate portion 69, similarly a short vertical side edge
portion 74 of the rear plate
portion 69 extends beyond the corresponding vertical side edge of the front
plate portion 69. The rear
plate portion 69 has a double L-shaped extension base 75 which has an L-shaped
bottom edge portion
76. The side plate 68 may be slidably mounted to the base 10 by sliding
sideways to engage the L-
shaped bottom edge portion 76 with the L-shaped elongated slot 66 and also the
short bottom edge
portion 72 of the rear plate portion 70 would simultaneously engage with the
second elongated slot
67 on the periphery rim of the base 10 such that the side plate 68 is securely
held in place.
A reinforcing retainer 77 located in the middle of the elongated slot 66 may
be integrally
formed in the base 10 in order to strengthen the outer edge portion of the
elongated slot 66. Similarly
a reinforcing retainer 78 is also formed in the middle of the elongated slot
67. With such provision,
right angle cut outs 79 and 80 are formed in the lower corners of the rear
plate portion of the side
plate 68 and similar cut outs are also formed in the L-shape bottom edge
portion 76 so that the
retainers 77 and 78 would not interfere with the engagement between adjacent
side plates located and
the middle of the base 10.
Pre-formed accurate openings having predetermined shapes such as a rectangular
opening 81
for mounting a common switch 82, or a circular opening 83 for mounting
indicator light, or an
arcuate opening 84 for mounting a conventional mufti-port connector may be
formed in the side
plates such that such auxiliary electrical components may be conveniently
mounted on the side plates
68 so that electrical connection between the breadboard and the auxiliary
electrical components may
be readily and easily made during the construction of the circuit. The short
vertical portions 74 and
68 of the rear plate portion and front plate portion respectively of adjacent
side plates engage with
one another to provide a closed joint.
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Similarly, an additional L-shaped cross section elongated slot 85 may be
formed on the edge
portion 14 of the base 10 and another longitudinal elongated slot 86 formed on
the peripheral rim of
the base 10 and located adjacent to the outer side wall of the edge portion 14
so that additional side
plates 68 may also be slidably mounted on the edge portion 14 of the base 10.
The top cover 51 for
this embodiment has opened longitudinal sides and mating longitudinal
elongated slots 87 and 88 are
formed in its underside adjacent its opened longitudinal side edge portions.
These mating longitudinal
slots 87 and 88 will engage with the top short edge portion of the rear plate
portion of the side plates
to hold the latter firmly in place once the top cover 51 is placed over the
base 10.
The lower edges of the side walls 89 and 90 are provided with recessed lips 91
and 92 which
will engage with two side slots 93 and 94 formed at the peripheral rim of the
base 10 to form an
intimate joint.
With respect to the above description then, it is to be realized that the
optimum dimensional
relationships for the parts of the invention, to include variations in size,
materials, shape, form,
function and manner of operation, assembly and use, are deemed readily
apparent and obvious to one
skilled in the art, and all equivalent relationships to those illustrated in
the drawings and described in
the specification are intended to be encompassed by the present invention.
Therefore, the foregoing is considered as illustrative only of the principles
of the invention.
Further, since numerous modifications and changes will readily occur to those
skilled in the art, it is
not desired to limit the invention to the exact construction and operation
shown and described, and
accordingly, all suitable modifications and equivalents may be resorted to,
falling within scope of the
invention.
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