Housing for a multi-board electronic module for a programmable controller system

A housing for a multi-board electronic module is disclosed. The housing comprises a rear wall, side walls, a top wall and a bottom wall cooperating to define an enclosure having an open front. Brackets located in the enclosure permit mounting of the electronic circuit boards in a substantially vertical orientation. Vent openings in the top and the bottom walls cooperate with the vertically oriented electronic circuit boards to permit air heated by the electronic components located on the circuit boards to escape the housing through the top wall vent openings and for permitting ambient air to enter the bottom wall vent openings. The ambient air replaces the escaping air and cools the components located on the electronic circuit boards. The housing can be either wall mounted or mounted in a register rack assembly.

DESCRIPTION 
1. Technical Field 
The present invention relates generally to a programmable controller system 
that is typically used to coordinate and manage operation of a 
manufacturing plant, and more particulary to a housing for a multi-board 
electronic module incorporated in such a system. 
2. Background Prior Art 
A manufacturing cell consists of a group of automated machine controls 
designed to work together and perform a complete manufacturing or process 
task. Such manufacturing cells can include a plurality of programmable 
controller modules, a plurality of I/O modules and/or a plurality of data 
communication modules. 
Cell controller modules have been developed which coordinate and manage 
operation of a manufacturing cell. 
Often such modules must be located near the particular equipment that they 
are controlling and, therefore, such modules are often located on a plant 
floor in a less than desirable environment. 
Because the electronics within the modules must be cooled, typically the 
modules have required internal cooling fans, as well as filters, for 
providing relatively cool ambient air. However filters are a constant 
source of maintenance, and failure of a fan can result in failure of the 
associated module. 
In addition, often a module can include a plurality of circuit boards 
Because of the harsh environment in which they must operate, as well as 
the nature of electronics in general, these circuit boards are subject to 
failure. As an entire manufacturing cell may depend on operation of a 
single circuit board, quick removal replacement of a failed circuit board 
is a necessity. 
Still further, the modules are often contained in a housing located in an 
electrical cabinet on the plant floor However prior housings were 
difficult to remove from their respective cabinet, greatly limiting 
flexibility. 
The present invention is provided to solve these and other problems. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide a housing for a multi-board 
electronic module of a programmable controller system. 
According to the invention, the housing comprises a rear wall, side walls, 
a top wall and a bottom wall which cooperate to define an enclosure having 
an open front. A removable cover closes the open front; 
Means located in the enclosure are provided for mounting the electronic 
circuit boards in a substantially vertical orientation. 
It is comprehended that the mounting means comprises a plurality of 
vertically oriented slots located on the rear wall, each of the slots 
adapted to receive an electrical connecting tab of a corresponding one of 
the electronic circuit boards and a substantially horizontal securing 
bracket disposed between the side walls proximate the housing front, the 
securing bracket including a plurality of elastomeric grooves, one of the 
grooves corresponding with each of the slots, the grooves adapted to 
engage and thereby support a corresponding one of the electronic circuit 
boards. 
The housing further includes vent openings in the top and the bottom walls 
which cooperate with the vertically oriented electronic circuit boards to 
permit air heated by the electronic circuit boards to escape the housing 
through the top wall vent openings and for permitting ambient air to enter 
the bottom wall vent openings The ambient air replaces the escaping air 
and cools the electronic circuit boards. 
It is comprehended that the housing include a cap enclosing a portion of 
the top wall and a portion of the rear wall, the cap defining mounting 
support surfaces for the housing. 
It is further comprehended that the cap have a front face set back from the 
housing front and defining an abutment. The abutment is adapted to 
cooperate with a substantially horizontal latch member of a register rack 
assembly to retain the housing in the register rack assembly. 
Other features and advantages of the invention will be apparent from the 
following specification taken in conjunction with the following drawings.

Detailed Description 
While this invention is susceptible of embodiment in any different forms 
there is shown in the drawings and will herein be described in detail a 
preferred embodiment of the invention with the understanding that the 
present disclosure is to be considered as an exemplification of the 
principles of the invention and is not intended to limit the broad aspect 
of the invention to embodiment illustrated. 
This application is related to commonly assigned, co-pending application to 
Maggelett, et. al., filed 17 Mar. 1989, Ser. No. 325,414 our, the 
specification of which is expressly incorporated by reference. 
A housing, generally designated by reference numeral 8, is illustrated in 
FIG. 1. 
The housing 8 encloses a plurality of circuit boards, discussed below, to 
produce an electronic module of the type used in a programmable controller 
system which can be used in multiple configurations to provide substantial 
system design and functional flexibility. The electronic module can be, 
for example, a SY/GATE.RTM. Class 8054 Minicell Controller, sold by Square 
D Company, assignee of this application. 
The housing 8 includes a rear wall 10, side walls 12, a top wall 14 and a 
bottom wall 16. The walls 10, 12, 14 and 16 cooperate to define an 
enclosure that has an front opening 20 defining a portion of the front 
wall of the housing 8. 
The housing 8 has a plurality of mounting slots 22 adapted to receive an 
electrical connecting tab 21 each of a plurality of circuit boards 23 
(FIGS. 2, 3), each for mounting one of the circuit boards 23 in a vertical 
orientation within the housing 8, as will be described in greater detail 
later. 
A cover plate 24 (FIG. 1) is provided to cover the front opening 20 after 
the circuit boards 23 have been mounted in the housing 8. 
According to one aspect of the invention, the housing 8 is provided to 
dissipate heat generated by components on the circuit boards 23 within the 
housing 8 without a need for cooling fans and filters, which are normally 
considered mandatory for this type of construction. The heated air 
naturally rises, and escapes from the housing 8 via upper vents 25 in the 
top wall 14 (FIG. 1). The heated air is replaced by ambient air which 
enters the housing via lower vents 26 in the bottom wall 16 (FIG. 4). 
Communication ports for connecting the electronic module contained within 
the housing 8 to other, external devices are located in the bottom wall 16 
to limit the amount of space required. 
As illustrated in FIG. 4, the bottom wall 16 consists of first and second 
segments 30, 31 located adjacent to the front opening 20 and the rear wall 
10, respectively. Each of the first and second segments 30 31 has a 
plurality of the lower vents 26. 
The bottom wall 16 includes a recess portion 34 between the first and 
second segments 30, 31, and the recess portion 34 is defined by a 
plurality of spaced, narrow strips 36 that are spaced from each other to 
define a plurality of elongated slots 40. 
The slots 40 are designed to receive mounting plates 562 and 56b that 
mount, inter alia, various communication ports. 
For example, a first mounting plate 56a is located in a first one of the 
slots 40 and has a power input port 60 which receives a first plug 62 
coupled to a power source (not shown). Also, the first mounting plate 56a 
has a multi-pin port 64 for receiving a second plug 66 of a portable 
external floppy disk drive. The first mounting plate 56a preferably also 
has a plurality of square openings 68 to provide additional ventilation 
into the housing 8. 
The power supply port 60 is electrically connected to internal circuitry 
(not shown) which converts received AC power to appropriate levels of DC 
power for internal operation, as is well known in the art. 
A second mounting plate 56b has a speaker port 72 therein for receiving a 
plug 74 that connects to an external speaker (not shown). 
Additional ports can be provided wherever desired. For example, a further 
plate 80 has a monitor port 82 which receives a monitor plug of an EVA 
monitor while a printer port 86 is adapted to receive a printer plug 88 
that forms part of a printer (not shown). 
The remaining ones of the slots 40 that are not used for ports can be left 
open to define an additional inlet for ambient air, or they can be covered 
by a grill plate 90 which has a plurality of openings 96 therein. 
Referring again to FIG. 1, the upper vents 25 are arranged in rows, with a 
solid section between each row. This solid section is utilized for 
supporting a plurality of guide members 102 (FIG. 3) that receive upper 
edges of the circuit boards 23. 
As illustrated in FIGS. 2, 3 and 5, a securing bracket 106 extends across 
the front opening 20. As more specifically illustrated in FIG.(b) 5, the 
securing bracket 106 has resilient grooves 107 formed of an elastomeric 
material for receiving the front edge of the circuit boards 23 and 
maintaining the circuit boards 23 mounted in the housing 8. 
In certain applications, the housing 8 is wall mounted, as in an electrical 
cabinet. In other applications the housing 8 is mounted in a register rack 
assembly 112, as illustrated in FIG. 6. 
Referring to FIG. 1, a cap 114 covers portions of the rear wall 10 and the 
top wall 14. The cap 114 has a face 116 which forms an abutment. 
Referring again to FIG. 6, the face 116 cooperates with a horizontal latch 
member 120 in the register rack assembly 112 to maintain the housing 8 
therein. The horizontal latch member 120 pivots about pivot pins 122 to 
move from a closed position, as illustrated in FIG. 6, upwardly to an open 
position. A more detailed description of the register rack assembly 112 
and the latch member 120 is contained in the above incorporated, copending 
application, our Ser. No. # 07/325,414. 
It will be understood that the invention may be embodied in other specific 
forms without departing from the spirit or central characteristics 
thereof. The present examples and embodiments, therefore, are to be 
considered in all respects as illustrative and not restrictive, and the 
invention is not to be limited to the details given herein.