Information
-
Patent Grant
-
6707256
-
Patent Number
6,707,256
-
Date Filed
Tuesday, June 25, 200222 years ago
-
Date Issued
Tuesday, March 16, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Wong; Don
- Tran; Thuy Vinh
Agents
- Greer, Burns & Crain, Ltd.
- Kolehmainen; Philip M.
-
CPC
-
US Classifications
Field of Search
US
- 315 112
- 315 113
- 315 114
- 315 115
- 361 622
- 361 627
- 361 631
- 361 634
- 361 673
- 361 676
- 361 678
- 361 690
- 361 703
- 361 709
- 361 748
-
International Classifications
-
Abstract
A self contained multiple dimming channel package includes a housing with a main power circuit board supported on its bottom wall and a control circuit board extending laterally and vertically to baffle air flow through the housing. A cross flow cooling fan forces air through an opening in the control board and across power switching modules and toroidal chokes mounted to the main board. Each power switching module includes a heat sink with fins parallel to the air flow, and the chokes are mounted in rows with their central openings aligned with the air flow. The power switching modules include circuits attached to the heat sinks with terminals releasably plugged into mating connectors on the main board. Circuit breaker switches are snapped into place in the housing. The front corners of the housing are provided with integral mounting bracket and handle members.
Description
FIELD OF THE INVENTION
The present invention relates to dimmers for electric lamps, and more particularly to an improved dimmer pack suitable for rack mounted and stand alone stage, studio and architectural lighting applications and that is small in size, reliable and inexpensive to manufacture.
DESCRIPTION OF THE PRIOR ART
Luminaires for theatrical and architectural applications are provided with power by phase angle dimmers so that the lamps of the luminaires can be dimmed to operate at selected light levels. Phase angle dimmers for this purpose are well known, and typically include solid state switches such as SCRs for interconnecting an AC power source to a lamp load. AC voltage from the source is sinusoidal. A phase control circuit renders a solid state switch conductive at a point during a half cycle of the sinusoid, the point being selected to supply to the lamp a lamp operating pulse having a desired quantity of power in order to produce a desired level of light.
Dimmers are often provided in the form of modules or packs suitable for mounting in a rack along with other dimmers and, in some applications, with control modules. Known dimmer modules can include a plurality of dimmer channels in a single modular pack for controlling a plurality of lighting loads. One example of a rack mounted dimmer module of this type is disclosed in U.S. Pat. No. 4,972,125 of Cunningham and Esakoff. The dimmer module disclosed in that patent requires external control and is not self contained. Self contained dimmer packs including all of the functionality required between the mains power supply and the lighting load may be used as stand alone units as well as in racks. In a stand alone application, it would be desirable to include convenient handles integrated into the design.
One of the goals in the design of dimmer packs is to combine high power capability and the ability to provide dimming control of multiple lighting channels, while achieving a small size. A difficulty in achieving this goal is heat dissipation. Components of the dimming circuitry, including high speed solid state switching devices and inductive chokes required for EMI suppression, generate substantial heat at high power levels. Small size results in high component and power density. Resulting high temperatures can interfere with dimmer operation and can decrease component life. Adequate cooling is important, but is difficult to achieve, particularly in a small package size operating at high power levels.
Another goal in dimmer pack design is to reduce cost. A dimmer pack typically has high voltage solid state power switching circuits, often provided with heat sinks, and inductive chokes. Also included are input interconnections for power supply mains with associated overload protection and switching and outputs for connection to the controlled lighting loads. An input for control network cabling and a user interface are typically used, together with low voltage control circuitry. A major cost factor of known dimmer packs is the labor required to mount and interconnect the many required components.
Dimmer packs must withstand rough physical treatment, for example when used for traveling theatrical productions, concerts and the like. Another goal in dimmer pack design is to provide a robust, sturdy construction able to withstand substantial forces without damage.
SUMMARY OF THE INVENTION
A primary object of the present invention is to provide an improved dimmer pack. Other objects are to provided a dimmer pack that is small in size and has high power capacity with multiple channels but is efficiently cooled; to provide a dimmer pack that that is easy and quick to assemble with low labor cost; to provide a dimmer pack that is sturdy and rugged; to provide a dimmer pack that includes convenient and strong handles integrated into the pack; and to provide a dimmer pack overcoming disadvantages of known dimmer modules and packs.
In brief, in accordance with the invention there is provided a dimmer pack for electrical lighting loads including a housing having front and rear walls spaced apart in a longitudinal direction, a bottom wall, a top wall and opposed side walls spaced apart in a lateral direction. A printed circuit main board within the housing overlies the bottom wall and is spaced from the top wall. A printed circuit second board in the housing is adjacent to the main board. The second board extends laterally between the side walls and extends vertically between the main board and the top wall and baffles air flow over the main board between the front and back walls. Cooling air inlet vents are in the housing adjacent the front wall and cooling air outlet vents are in the housing adjacent the rear wall. A high voltage switching circuit assembly and a choke are mounted on the main board at one side of the second board. An air passage opening in the second board defines a cooling air path through the second board between the inlet and outlet vents, the air passage opening being aligned with the switching circuit assembly and choke. A fan supported in the housing moves air along the cooling air path.
In brief, in accordance with another aspect of the invention, there is provided a dimmer pack for electrical lighting loads including a housing and a printed circuit board in the housing. A high voltage switching module includes a heat sink. The heat sink includes a planar base portion having first and second opposed surfaces. A plurality of cooling fins extend from the first surface. A solid state high voltage switching circuit is attached to the second surface. A plurality of first electrical connectors connected to the switching circuit project away from the second surface. A plurality of second connectors are mounted on the circuit board. The second connectors are releasably mated with the first connectors for supporting the switching module on the circuit board and for making electrical connections between the circuit board and the switching circuit.
In brief, in accordance with another aspect of the invention, there is provided a circuit breaker mounting assembly for an electrical device including a housing having a panel. The panel has opposed parallel flanges. A circuit breaker has front, top and bottom walls with recesses in the top and bottom walls. The circuit breaker is mounted adjacent the panel with the front wall against the panel and the top and bottom walls interfacing with the flanges. Tangs on the flanges are received in the recesses for locking the circuit breaker onto the panel.
In brief, in accordance with another aspect of the invention, there is provided a rack mountable electrical unit including a housing having front and side walls defining front housing corners and an integral bracket and handle member at each of the front housing corners. Each of the members includes a planar mounting portion attached to the housing, a mounting bracket projecting laterally from the housing beyond one of the side walls, and a handle spaced from and located in front of the bracket, the handle projecting laterally from the housing beyond one of the side walls.
BRIEF DESCRIPTION OF THE DRAWING
The present invention together with the above and other objects and advantages may best be understood from the following detailed description of the preferred embodiment of the invention illustrated in the drawings, wherein:
FIG. 1
is an isometric front, top and side view of a dimmer pack constructed in accordance with the present invention;
FIG. 2
is a front view of the dimmer pack;
FIG. 3
is a rear view of the dimmer pack;
FIG. 4
is an isometric view like
FIG. 1
with the top and rear walls removed to reveal the interior of the dimmer pack;
FIG. 5
is a block diagram illustrating the electrical component packaging of the dimmer pack;
FIG. 6
is a rear, top and side isometric view of the main and control circuit boards of the dimmer pack;
FIG. 7
is a cross sectional view of the dimmer pack taken along the line
7
—
7
of
FIG. 2
;
FIG. 8
is an enlarged cross sectional view of one of the main circuit board mounts taken along the line
8
—
8
of
FIG. 7
;
FIG. 9
is an end view of one of the high voltage switching modules of the dimmer pack;
FIG. 10
is a bottom, end and side isometric view of the high voltage switching module;
FIG. 11
is a schematic drawing of the circuits of the high voltage switching module;
FIG. 12
is a top, rear and side isometric view of the front panel of the housing of the dimmer pack with three circuit breaker switches mounted in place;
FIG. 13
is an enlarged sectional view showing the mounting of one circuit breaker switch in the front panel;
FIG. 14
is an isometric view of a corner bracket and handle member of the dimmer pack; and
FIG. 15
is an enlarged fragmentary top view of the bottom and side walls at a front corner of dimmer pack showing the attachment of the corner bracket and handle member.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Having reference now to the drawings, there is illustrated a dimmer pack generally designated as
20
and constructed in accordance with the principles of the present invention. The dimmer pack
20
is used to control the energization levels of lighting loads, such as luminaires used for stage, studio and architectural applications. The dimmer pack
20
is a self contained multiple channel dimming controller including high voltage phase control switching channels together with user input and network capabilities and low voltage controls.
A housing
22
of the dimmer pack
20
includes a front wall
24
, a rear wall
26
(
FIG. 3
) spaced longitudinally from the front wall
24
, a bottom wall
28
, a top wall
30
and laterally spaced side walls
32
and
34
. The bottom wall
28
and side walls
32
and
34
are portions of a single formed panel having a U-shaped cross section (FIG.
4
). The rear and top walls
26
and
30
are stamped and formed metal panels. The front wall
24
includes a metal front panel
36
(
FIG. 12
) and a molded plastic face panel
38
(FIGS.
4
and
7
).
The dimmer pack
20
of the present invention provides self contained, high power, multiple channel dimming in a small, rugged and easily portable package. The housing
22
is sized for slide in, front to back mounting in a industry standard DIN nineteen inch rack. The dimmer pack
20
can be provided in many configurations and power ratings, and can include up to twelve independently controlled dimming channels of up to ten amps per channel. Yet this high power density is accomplished in a package that is only two U (standard rack height unit equal to 1.75 inches), or three and one-half inches, in height. Even at this high power level and small size, the dimmer pack
20
is efficiently and reliably cooled.
When rack mounted, or when used as a stand alone unit, the front wall
24
including face panel
38
is readily accessible to the user. The front wall
24
of the dimmer pack
20
includes a row of switch levers
40
, one for each dimming channel, for turning the dimmer channels off and on. Each switch lever
38
is part of a circuit breaker switch
40
mounted upon the front panel
36
(
FIGS. 12 and 13
) that alos provides overload protection. A similar control circuit switch lever
44
is associated with a control circuit breaker switch
46
. The front wall
24
also provides a user interface
48
with a display
50
and a plurality of user operated input switches
52
. A pair of network connector receptacles
54
are also located at the front wall
24
, permitting the dimmer pack
20
to be connected into a network, such as a DMX network, and permitting the dimmer pack
20
to be daisy chained in the network with other dimmer packs and other network capable devices.
Switch levers
40
are shown in
FIGS. 1 and 2
in the lower, off position, and switch lever
44
is shown in the upper or on position. Each switch lever
40
and
44
is nested in a panel configuration including a recess
56
that presents the lever
40
or
44
in its lower, off state in a position that is easy for the user's finger to engage and move upward to the on position. In the on position, as seen with lever
44
in
FIGS. 1 and 2
, the lever is protected between a pair of abutments
58
that shield the lever and prevent inadvertent movement of the lever from the on position to the off position. Recesses
60
adjacent to the network connector receptacles
54
provide access for fingers to grip network connectors (not shown) mated in the receptacles
54
. Indicator lamps associated with the circuit breaker switches
42
and
46
may be visible at or below the recesses
60
.
The rear wall
26
is accessible to the user when the dimmer pack
20
is installed in either a rack mounted or a stand alone unit. The rear wall
26
(
FIG. 3
) provides an entry or connection point
62
for a mains power supply. The mains entry
62
can be an opening or a knock out for an opening through which a power supply cable enters the housing
22
. The dimmer pack
20
can be configured for two or three phase power using
230
or
110
volt or other power supplies that are conventional for example in the U.S.A. or Europe of elsewhere in the world. The rear wall
26
also includes a series of lighting load output receptacle connectors
64
for each dimming channel. In the illustrated embodiment the six illustrated output connectors
64
are duplex, each serving two independently controlled lighting loads, for a total of twelve loads. The rear wall panel
26
is preferably a modular part that can be tailored to accommodate many different types of power cables and lighting load connectors.
Compact and efficient packaging of the components of the dimmer pack
20
contributes to low assembly cost and to high power density in the small size housing
22
. As seen in
FIGS. 4-6
, the dimmer pack includes a main power printed circuit board or motherboard
66
and a control printed circuit board or daughter board
68
. The main board
66
is mounted within the housing
22
where it is supported upon and overlies the bottom wall
28
. It extends laterally most of the distance between the side walls
32
and
34
and longitudinally a substantial part of the distance between the front and rear walls
24
and
26
. The main board
66
includes circuit paths (not shown) that connect high power circuit components of the dimmer pack
20
, including power supply transformers
70
and
72
and filter capacitors
74
.
Edge connectors
75
on the main board
66
support the control board
68
and extend electrical connections to circuit paths (not shown) on the control board. The control board
68
supports a low voltage control circuit
76
including various low voltage circuit components
77
of the dimmer pack
20
as well as a microprocessor
78
. Microprocessor
78
receives inputs from the user interface
48
and/or from one of the network connection receptacles
54
and supplies at its outputs control signals used in phase control dimming of lighting loads connected to the output connectors
64
.
The main board
66
also includes three mounting areas or module nests
80
for releasable, plug in connection of high power switching modules
82
best seen in
FIGS. 9 and 10
. Toroidal chokes
84
are also mounted on the main board
66
. The main board carries arrays
85
and
86
of female electrical terminals located at the front and rear edges of the board
66
. Terminals
84
are used for making connections (seen only schematically in
FIG. 5
) between the main board
66
and the circuit breaker switches
42
. Terminals
86
are used to make connections (seen only schematically in
FIG. 5
) between the main board
66
and the output load connectors
64
.
As best illustrated in the block packaging diagram of
FIG. 5
, a small network connector circuit board
88
carries the network receptacles
54
, and is connected to the control circuit board
68
by a wiring harness
90
. The user interface
48
is connected to the control board
68
by a ribbon cable
92
(also seen in FIGS.
4
and
7
). The control circuit breaker switch
46
is connected to the control board by a wiring harness
94
. The control board
68
is connected to the main or power board
66
by the edge connectors
75
.
A group of power entry screw terminal assemblies
96
(
FIG. 6
) is supported at a rear corner of the main board
66
near the mains power supply point
62
. Individual power supply conductors
98
(
FIG. 5
) are terminated in these screw terminals
96
. A wiring harness
100
connects the screw terminal assemblies
96
to the circuit breaker switches
42
. The screw terminal assemblies
96
include male terminal tabs
102
for connection to terminals at one end of the harness
100
. The circuit breaker switches
42
include screw terminals
104
(
FIG. 12
) for connection to the opposite end of the harness
100
. male terminal tabs may be used instead of the screw terminals
104
. The wiring harness connections between the screw terminal assemblies
96
and the circuit breaker switches are selected to configure the dimmer pack
20
for the type of mains power supply used with the dimmer pack
20
and for the number of dimming channels to be employed. The illustrated dimmer pack
20
has twelve independently controlled dimming channels, but fewer channels may be used for some applications. In this case, less than twelve circuit breaker switches
42
are employed. Male terminal tabs
106
of the circuit breaker switches
42
are connected to terminals
85
of the main board
66
by a wiring harness
108
.
The control circuit breaker switch
46
has male terminal tabs
109
(
FIG. 12
) connected by the wiring harness
94
to the main board
66
. The user operates the control circuit breaker switch
46
to place the low voltage control circuit
76
alternatively in a standby, off condition or in an operating or on position. In the on position, power is supplied to the control board
68
through an edge connector
75
.
Phase controlled power from the main board
66
is supplied to the output connectors
64
by a wiring harness
110
. At one end of the harness
110
, conductors are connected to terminals
86
at the rear of the main board
66
. At the other end of harness
110
, the conductors are terminated to suitable terminals associated with the output connectors
64
.
The term wiring harness is used to mean any type of cable or group of conductors, whether in a cable or discrete, used to interconnect the described components of the dimmer pack
20
. For the most part these harnesses are shown only in schematic form and only in
FIG. 5
in order that they not obscure other views of the drawings. The conductors of each harness preferably include electrical connectors and terminals able to mate with the illustrated terminals such as, for example, terminals
85
,
86
,
102
,
104
and
106
. In this way, a minimum of time and effort is required to configure, assemble and interconnect the components of the dimmer pack
20
.
The high power switching modules
82
are received in the modules nests
80
with a simple plug in connection. This has the advantages of facilitating initial assembly as well as field replacement of the modules
82
. One nest
80
is illustrated in detail in FIG.
6
. It includes an array of eight female quick connect terminals
112
on the main board
66
. The nest
80
also includes a female in line pin receptacle connector or header
114
.
A switching module
82
is seen in
FIGS. 9-11
. The module
82
includes an extruded metal heat sink
116
made of a material such as aluminum having good heat transfer characteristics. The heat sink
116
has a planar base portion
118
with a recess
120
in one surface. A number of parallel heat transfer fins
122
project from the side of the base
118
opposite the recess
120
. High voltage switching circuits
124
and a heat sensing unit
126
(
FIG. 11
) are encapsulated in recess
120
by potting compound
128
.
In the illustrated twelve channel embodiment of the invention, each switching module
82
includes four dimmer channels, and thus includes four high voltage switching circuits
124
. Other configurations can have fewer modules or fewer switching circuits per module.
As seen in
FIG. 11
, each switching circuit
124
includes a pair of SCRs
130
with gate biasing resistors
132
for controlling conduction during alternate power supply half cycles between a pair of main power terminals
134
. The SCRs
130
are controlled by control signals received at control input terminals
136
relative to a ground input terminal
138
. Optically isolated switches
140
and resistors
141
couple control signals from the terminals
136
to the SCRs
130
. The low voltage control circuit
76
including microprocessor
78
supplies control signals from the control board
68
and through edge connectors
75
to operate the SCRs
130
to achieve selective lighting load phase angle dimmed levels in accordance with inputs received from the user interface
48
and/or the network connected to a connector receptacle
54
.
The switching module
82
also includes the onboard heat sensing unit
126
. Unit
126
is connected to terminals
142
and provides a temperature responsive signal to the low voltage circuit
76
and microprocessor
78
through a circuit including edge connectors
75
. This signal may used for example to discontinue operation of one or more dimming channels in response to an excessive temperature condition.
As seen in
FIGS. 9 and 10
, the main power terminals
134
of the module
82
extend from base
118
of the heat sink
116
in a direction opposite from the cooling fins
122
. The terminals
136
,
138
and
140
are pin terminals and extend in the same direction, parallel to the power terminals
143
, and are arrayed in a line.
The switching module
82
is seated in the module nest
80
and is attached to and supported by the main board
66
with a simple plug in operation. When the module
82
is pressed into the nest
80
, the power terminals
134
are slideably and frictionally received into the female nest terminals
112
. Similarly the pin terminals
136
,
138
and
140
are slideably and frictionally received into the pin receptacle connector
114
. This simple plug in operation makes all of the electrical connections between the circuit board
66
and the module
82
, and no other connections need to be made in any other way from the module
82
to other components of the dimmer pack
20
. In addition, the electrical connections between the module
82
and the module nest
80
provide the entire mechanical attachment and retention of, and support for, the switching module
82
upon the board
66
. No fasteners or hold downs are needed. Assembly of the switching modules
82
into the dimmer pack
20
is easy and fast. In addition, in the event of failure of an SCR
130
or other failure, it is a simple matter in the field to unplug a faulty switching module
82
and replace it with a new module.
The electrical components of the dimmer pack
20
radiate heat in use. The high voltage switching circuits
124
, particularly the SCRs
130
, and the chokes
84
are primary sources of generated heat. The small size and the high power density of the dimmer pack
20
impose a requirement for substantial and efficient cooling. The dimmer pack
20
includes a highly effective cooling system generally designated as
144
permitting continuous operation of the multiple dimmer channels at high output levels, even under adverse ambient conditions.
Cooling system
144
includes cooling air intake vents
146
and
148
located at the front wall
24
of the housing
22
. An upper vent
146
(
FIG. 2
) spans the full width of the housing
22
between the top wall
30
and the face panel
38
. A similar lower vent
148
extends the full width of the housing
22
, except that it is interrupted at the location of the user interface
48
. Vents
146
and
148
provide a large area for entry of cooling air from the front of the housing
22
. Heated cooling air is exhausted from the rear portion of the housing
22
. The side walls
32
and
34
include rearward outlet vents
150
. The rear wall
26
also includes a series of outlet vents
152
. The outlet vents
150
and
152
also provide a large area for the removal of heated air.
The main power board
66
is mounted upon the bottom wall
28
, and the flow of air through the housing
22
is above the board
66
. The control circuit board extends laterally across the housing
22
between the side walls
32
and
34
, and extends vertically from the main board
66
to the top wall
30
. The control board
68
therefore acts as a baffle and prevents uncontrolled air flow from the front to the back of the housing
22
.
A window or opening
154
in the control board
68
permits flow through the control board
68
from the front to the back of the housing
22
. As best seen in
FIG. 6
, the opening
154
is aligned with the primary heat generating components of the dimmer pack
20
, namely the switching modules
82
and the chokes
84
. As a result, substantially all of the cooling air flow is directed where it is most needed. Heat transfer into the air flow is maximized.
Effective heat transfer is augmented by the configurations, locations and orientations of the switching modules
82
and chokes
84
. The fins
122
of the module heat sinks
116
are aligned longitudinally, front to back, in the housing
22
. Cooling air flowing from the opening
154
flows without change of direction through the spaces between the fins
122
to maximize heat transfer from the heat sinks
116
and minimize air flow obstruction.
The chokes
84
include windings
156
wound on toroidal cores
158
of magnetic metal material. Each choke
84
has a central opening
160
. In the illustrated configuration there are twelve chokes
84
, one for each dimming channel. Other configurations may use fewer chokes
84
. The chokes
84
are arrayed in rows on the main board
66
between and adjacent to the module nests
82
. Each choke
84
in each row is oriented so that the axis of its central opening
160
is disposed longitudinally, front to back. The central openings
160
of the chokes
84
in each row are aligned. Cooling air flows around and over the chokes
84
and through the central openings
160
without change of direction in order to maximize heat transfer from the chokes
84
to the air flow and in order to minimize obstruction to the air flow.
Cooling air is forced through the housing
22
by a fan
162
. The fan
162
is an elongated cross flow fan oriented laterally in the housing
22
and mounted upon the control board
68
over the opening
154
. The fan may be a Panasonic Model FCB34 fan available from Matsushita Electric Corporation of America, Secaucus, N.J. The fan
162
is connected to receive power from the main board
66
by a wiring harness
164
(FIG.
5
). The elongated exit
166
(
FIG. 7
) of the cross flow fan
162
extends laterally across the width of the housing
22
and directly communicates with the opening
154
. As a result the fan
162
draws cooling air from the region in front of the control board
68
and forces the air through the opening
154
into the region behind the control board
68
.
The cooling air flow path is best seen in FIG.
7
. Cool air enters at the front of the housing
22
through upper and lower inlets
146
and
148
. This air enters the cross flow fan
162
and is forced through the fan exit
166
and opening
154
in control board
68
to the rear of the board
68
. The baffle effect of the control board
68
prevents air from bypassing this cooling path. As a result, substantially all of the cooling air is directed from the opening
154
across the switching modules
82
and the chokes
84
for efficient, maximized cooling of these heat generating components. Air exits at and near the rear of the housing
22
through vents
150
and
152
. In both rack mounted and stand alone applications, the exhausting of heated air from the rear of the dimmer pack is advantageous and avoids the reentry of heated air into the front of the housing
22
.
The construction of the dimmer pack
20
is strong and rugged in order to withstand forces, shocks and stresses encountered in everyday use. In addition to discrete components such as the relatively heavy transformers
70
and
72
, the main power board
66
supports the control board
68
, including the fan
162
and other components on the board
68
, the massive chokes
84
and the switching modules
82
. The total weight carried by the board
66
can exceed ten pounds. To prevent damage to the board resulting from this weight, a sturdy one-eighth inch board is used, and it is mounted to the bottom wall
28
using a number of shock absorbing mounts
168
as seen in FIG.
8
.
At its corners the main power board
66
is provided with mounting holes
170
for receiving the mounts
168
. The bottom housing wall
28
is provided with an upwardly offset boss
172
aligned with each mounting position. A resilient grommet
174
is received in the hole
170
and receives an enlarged shank portion
176
of a flange head screw
178
threaded down through a hole
180
in the boss
172
. A sleeve
182
limits compression of the grommet
174
. The resilient grommet
174
mounted in this manner dampens shock transfer between the housing
22
and the main power board
66
.
A snap in mounting system
184
(
FIGS. 12 and 13
) is provided for the circuit breaker switches
42
and
46
. Each switch
42
and
44
includes opposed recesses
186
in its top and bottom walls. The metal front panel
36
has upper and lower flanges
188
and
190
that receive and closely overlie the tops and bottoms of the circuit breaker switches
42
and
46
. The flange portions
188
and
1909
are subdivided by slots
192
into flexible tab portions
194
. The tabs
194
are provided with locking projections or tangs
196
extending down from the upper flange
188
and up from the lower flange
190
. A circuit breaker switch
42
or
46
is mounted to the panel
36
simply by pressing it forward as the tabs
194
flex until the tangs
196
snap into the recesses
186
and lock the circuit breaker switch in place as seen in FIG.
13
. Openings
197
in the panel
36
permit the levers
40
and
44
to extend through the panel where they are accessible to the user. Openings
195
may be provided for viewing indicator lights on the front of the circuit breaker switches
42
and
46
. The snap in mounting is quick and easy and the expense and labor cost of using fasteners is avoided.
Each of the front corners of the dimmer pack
20
is provided with an integral handle and mounting flange body
198
(FIGS.
14
and
15
). The bodies
198
are stamped and formed from sturdy, thick sheet metal. Each has a planar mounting portion including a forward side panel
200
and an inwardly offset rear side panel
202
. The forward panel
200
has a pair of weld access holes
204
, while the rear panel
202
has a boss
206
with a third weld access hole
208
. A mounting bracket
210
extends outwardly from the front panel
200
, and a curved and outwardly extending handle portion
212
is formed in front of the bracket
210
. Handle portion
212
is smoothly curved and is convex toward the front of the dimmer pack
20
. The bodies
198
are symmetrical top to bottom around a central horizontal plane, so that identical bodies
198
can be used at both front corners.
The bodies
198
are secured to the housing side panels
32
and
34
. As seen in
FIG. 15
, a slot in the side panel permits the forward panel
200
to lie against the exterior surface of the side panel while the rear panel
202
lies against the interior surface. A boss
215
(
FIG. 1
) on the side panel registers with the boss
206
of the rear panel
202
and in cooperation with the slot in the side wall accurately positions the body
198
. A three point weld is made at the weld access openings
204
and
208
for a very strong interconnection of the bodies
198
to the housing
22
. The handles
212
are used for transporting and handling the dimmer pack
20
. For rack mounting, the mounting flanges can be fastened to the rack using openings
214
in the flange. Openings
216
in the handle are aligned with the openings
214
(see
FIG. 2
) to afford access to fasteners located at the flange openings
214
.
While the present invention has been described with reference to the details of the embodiment of the invention shown in the drawing, these details are not intended to limit the scope of the invention as claimed in the appended claims.
Claims
- 1. A dimmer pack for electrical lighting loads comprising:a housing having front and rear walls spaced apart in a longitudinal direction; a bottom wall, a top wall and opposed side walls spaced apart in a lateral direction; a printed circuit main board within said housing overlying said bottom wall and spaced from said top wall; a printed circuit second board in said housing adjacent said main board, said second board extending laterally between said side walls and extending vertically between said main board and said top wall and baffling air flow over said main board between said front and back walls; cooling air inlet vents in said housing adjacent said front wall and cooling air outlet vents in said housing adjacent said rear wall; a high voltage switching circuit assembly mounted on said main board at one side of said second board; a choke mounted on said main board at said one side of said second board; an air passage opening in said second board defining a cooling air path through said second board between said inlet and outlet vents, said air passage opening being aligned with said switching circuit assembly and choke; and a fan supported in said housing for moving air along said cooling air path.
- 2. The dimmer pack claimed in claim 1, said switching circuit assembly and said choke being mounted between said second board and said rear wall.
- 3. The dimmer pack claimed in claim 2, said air passage opening extending laterally for a substantial part of the distance between said side walls, and said fan comprising an elongated cross flow fan covering said air passage opening and directing cooling air through said opening.
- 4. The dimmer pack claimed in claim 1, further comprising an edge connector supporting said second board on said main board.
- 5. The dimmer pack claimed in claim 1 further comprising a plurality of said switching circuit assemblies and a plurality of said chokes mounted on said main board.
- 6. The dimmer pack claimed in claim 5, each said switching circuit assemblies including SCRs.
- 7. The dimmer pack claimed in claim 1, further comprising a heat sink in heat transfer relationship with said switching circuit assembly, said heat sink having spaced, parallel fins, said fins extending in the longitudinal direction.
- 8. The dimmer pack claimed in claim 7, said choke including a toroidal core having a hollow center with an axis extending in the longitudinal direction.
- 9. The dimmer pack claimed in claim 7, said heat sink including a base, said fins extending from a first surface of said base, said switching circuit assembly being attached to a second surface of said base, said switching circuit assembly including a plurality of first terminals extending from said second surface of said base, and a plurality of second terminals on said main board releasable receiving said first terminals.
- 10. The dimmer pack claimed in claim 9, said first terminals comprising male terminals and said second terminals comprising female terminals receiving said male terminals with a plug in connection.
- 11. The dimmer pack claimed in claim 9, said first and second terminals comprising the only support for said switching circuit assembly and said heat sink on said main board and comprising the only electrical connections to said switching circuit assembly.
- 12. The dimmer pack claimed in claim 1 further comprising resilient supports mounting said main board on said bottom wall.
- 13. The dimmer pack of claim 1 further comprising low voltage control components including a microprocessor on said second board.
- 14. The dimmer pack of claim 1 further comprising user input devices on said front wall and load connectors on said rear wall.
- 15. A multiple channel dimmer pack for a plurality of electrical lighting loads, said dimmer pack comprising:a housing having front and rear walls spaced apart in a longitudinal direction; a bottom wall, a top wall and opposed side walls spaced apart in a lateral direction; a printed circuit main board within said housing overlying said bottom wall and spaced from said top wall; a printed circuit second board in said housing; at least one edge connector connecting said second board to said main board and supporting said second board on said main board, said second board extending laterally between said side walls and extending vertically between said main board and said top wall and baffling air flow over said main board between said front and back walls; cooling air inlet vents in said housing adjacent said front wall and cooling air outlet vents in said housing adjacent said rear wall; a plurality of high voltage switching modules each containing a heat sink, a switching circuit for an electrical lighting load and first electrical terminals; a plurality of module nests on said main board, each said nest including second electrical terminals releasably mated to said first electrical terminals; a plurality of chokes mounted on said main board, said chokes being toroids with open centers, said chokes being mounted in a row with said open centers aligned in the longitudinal direction; an air passage opening in said second board defining a cooling air path through said second board between said inlet and outlet vents, said air passage opening being aligned with said switching circuit assemblies and chokes; and a fan mounted in said housing for moving air along said cooling air path.
- 16. A multiple channel dimmer pack as claimed in claim 15, said air passage opening extending laterally for a substantial part of the distance between said side walls, and said fan comprising an elongated cross flow fan covering said air passage opening and directing cooling air through said opening.
- 17. A multiple channel dimmer pack as claimed in claim 16, each said switching module including a plurality of high voltage switching channels.
- 18. A multiple channel dimmer pack as claimed in claim 17, said chokes being mounted in a plurality of said rows.
- 19. A multiple channel dimmer pack as claimed in claim 15 further comprising low voltage control components including a microprocessor on said second board.
- 20. A dimmer pack for electrical lighting loads comprising:a housing; a printed circuit board in said housing; a high voltage switching module including a heat sink; said heat sink including a planar base portion having first and second opposed surfaces; a plurality of cooling fins extending from said first surface; a solid state high voltage switching circuit attached to said second surface; a plurality of first electrical connectors connected to said switching circuit and projecting away from said second surface; and a plurality of second connectors mounted on said circuit board, said second connectors being releasably mated with said first connectors for supporting said switching module on said circuit board and for making electrical connections between said circuit board and said switching circuit.
- 21. A dimmer pack as claimed in claim 20, said second surface including a recess, and said switching circuit being contained in said recess.
- 22. A dimmer pack as claimed in claim 21, said recess being filled with potting material encapsulating said switching circuit.
- 23. A dimmer pack as claimed in claim 20 comprising a plurality of said switching circuits attached to said second surface.
- 24. A dimmer pack as claimed in claim 23 comprising a plurality of said switching modules.
- 25. A dimmer pack for electrical lighting loads, said dimmer pack comprisinga housing having front and rear walls spaced apart in a longitudinal direction; a bottom wall, a top wall and opposed side walls spaced apart in a lateral direction; a power supply connection in said housing; a plurality of circuit breaker switches mounted on said front wall and connected to said power supply connection; a printed circuit main power board within said housing overlying said bottom wall and spaced from said top wall; said circuit breaker switches being connected to said main board; a printed circuit control board in said housing mounted on said main board, said control board extending vertically between said main board and said top wall; an edge connector supporting said control board on said main power board and connecting said control board to said main power board; low voltage control circuit components including microprocessor mounted on said control board; a user interface assembly mounted on said front wall and connected to said control board; a plurality of high voltage switching modules mounted on said main board; a plurality of inductive chokes mounted on said main board; and a plurality of lighting load connectors mounted on said rear wall and connected to said main board.
- 26. A dimmer pack as claimed in claim 25 further comprising a network connection mounted on said housing, said network connection being connected to said control board.
- 27. A dimmer pack as claimed in claim 26, said power supply connection being mounted on said rear wall and said network connection being mounted on said front wall.
- 28. A dimmer pack as claimed in claim 25 further comprising a cooling air opening through said control board, and a cooling fan mounted on said control board overlying said cooling air opening.
- 29. A dimmer pack as claimed in claim 28, said fan comprising a cross flow fan.
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Number |
Name |
Date |
Kind |
4972125 |
Cunningham et al. |
Nov 1990 |
A |
4977484 |
Cunningham et al. |
Dec 1990 |
A |
5352958 |
Cunningham et al. |
Oct 1994 |
A |
5699241 |
Fujikawa |
Dec 1997 |
A |
5770928 |
Chansky et al. |
Jun 1998 |
A |