BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to a bracket assembly for supporting terminal
block means on a circuit breaker and a related method for securing the bracket
assembly to the circuit breaker.
Background Information
Terminal blocks are mounted on the outside of a circuit breaker and are
electrically connected to the circuit breaker by wires which are drawn through
horizontal slots in the circuit breaker housing. Terminal blocks are generally connected
to auxiliary contact devices such as a bell switch which is used to provide an indication
of a tripped condition of the circuit breaker, or connected to a printed circuit board,
for remote communications on the functions that the PCB is performing. One
arrangement for securing the terminal block to the outside of a circuit breaker consists
of a terminal block which has two T-shaped members on its rear wall, each of which
fit and slide into a vertical slot on a sidewall of the housing.
Since only two slots are provided on the sidewall of the circuit breaker
housing, only one terminal block can be used in conjunction such a circuit breaker.
If additional terminal blocks are required, then additional slots need to be provided in
the sidewall of the housing, although they would unacceptably weaken the housing.
For a particular application, it is apparent that this arrangement has limitations in that
the number of slots dictate the number of terminal blocks which can be supported by
the circuit breaker.
In order to expand the capacity for supporting a number of terminal
blocks, a long bracket has been provided in some installations whereby several terminal
blocks are secured to the bracket. A problem with this type of arrangement is that the
bracket is unstable or wobbly and cannot be fixedly secured to the circuit breaker
housing. A further problem with this arrangement is that since the bracket is mounted
flush against the housing, plastic screws are needed to maintain electrical isolation
between the inside of the housing which contains the circuit breaker mechanism and
the outside of the housing. However, the walls of the housing are generally thin and
of poor material for tapping. Thus, plastic screws are not a satisfactory solution.
Heavy duty double stick tape has been suggested, but it also does not adequately secure
the bracket to the molded housing.
There remains, therefore, a need for a circuit breaker to accommodate
several terminal block assemblies alongside its outer housing wall on a bracket
assembly which is fixedly secured to the circuit breaker housing and which is
electrically isolated from the circuit breaker mechanism.
SUMMARY OF THE INVENTION
The present invention has met the above-described needs. It employs
a bracket assembly for a circuit breaker for supporting a plurality of terminal block
assemblies. The bracket assembly comprises a bracket member positioned against an
outer wall surface of the circuit breaker, a back-up plate positioned against an inner
wall surface of the circuit breaker in a pocket outside of a cavity containing the circuit
breaker mechanism, and fastening means for securing the bracket member and the
back-up plate to the wall of the circuit breaker and to each other. The bracket
member, the back-up plate, and the fastening means may be made of metal, such as
steel, since no components of the bracket assembly enter into the cavity containing the
circuit breaker mechanism. The bracket member has a shelf portion for supporting the
several terminal block assemblies and a leg portion which in the exemplary
embodiment has an aperture through which several leads are drawn for their electrical
connection to devices, such as an auxiliary switch and/or an alarm, a communications
system or a remotely located control device. The aperture in the leg portion of the
bracket member communicates with a slot in the shelf portion for extending wires from
the circuit breaker mechanism through the bracket assembly for their connection to the
several terminal block assemblies.
It is, therefore, an object of the present invention to provide support
means fixedly and stably secured to the circuit breaker for supporting several terminal
block assemblies and comprising components which remain outside of the cavity
containing the circuit breaker mechanism.
It is a further object of the present invention to provide a bracket
assembly for supporting a plurality of terminal block assemblies and to provide a
method for securing the bracket assembly to the circuit breaker housing.
These and other objects of the present invention will be fully understood
and appreciated from the following description of the invention upon reference to the
illustrations appended hereto.
BRIEF DESCRIPTION OF THE DRAWINGS
A full understanding of the invention can be gained from the following
description of the preferred embodiments when read in conjunction with the
accompanying drawings in which:
Figure 1A is an isometric view showing a terminal block assembly of
the prior art;
Figure 1B is an isometric view of the terminal block assembly of
Figure 1A rotated to show the T-shaped members used to mount the terminal block
assembly to the circuit breaker housing;
Figure 2 is an elevational view illustrating a sidewall of a circuit breaker
on which the terminal block assembly of the prior art and the bracket assembly of the
invention are mounted;
Figure 3 is an osometric view showing the bracket assembly and the
terminal block assemblies in exploded form;
Figure 4 is an elevational view similar to Figure 2 illustrating a sidewall
of a circuit breaker with the bracket assembly of the invention mounted thereon;
Figure 5 is a partial sectional view taken along lines 5-5 of Figure 4; and
Figure 6 is a top plan view taken along lines 6-6 of Figure 4 showing
the bracket assembly of the present invention and a partial view of the circuit breaker
on which it is mounted.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to Figures 1A, 1B, and 2, there is shown in Figures 1A
and 1B a terminal block assembly 10 of the prior art discussed hereinabove which
consists of T-shaped members 12 and 14 which fit and slide into slots 16 and 18 in a
sidewall 20 of a circuit breaker 22.
As particularly shown in Figure 1A, terminal block assembly 10 has
three compartments 10a, 10b, 10c which are connected by way of wires (not shown)
soldered to pads (also not shown) permanently mounted in the assembly and extending
into the circuit breaker, and a screw down clamp (not shown) for the user's wires in
a manner well known to those skilled in the art.
Referring to Figures 3, 4, 5, and 6 there is shown a bracket assembly 26
of the present invention which is mounted to an outer wall or sidewall 28 (Figure 3)
of a housing for a circuit breaker 24. Circuit breaker 24 is similar to circuit
breaker 22 of Figures 1A, 1B, and 2, and contains a circuit breaker mechanism (not
shown).
With particular reference to Figure 4, bracket assembly 26 comprises a
bracket member 30, a back-up plate 32, and fastening means, such as screws 34 and
36 which secure bracket member 30 and back-up plate 32 together in sidewall 28.
Bracket member 30 has generally an L-shaped configuration with a leg portion 30a and
a shelf portion 30b. Leg portion 30a has two members which are spaced apart and are
configured to form an aperture 38 which communicates with an opening 40 of shelf
portion 30b as shown in Figure 6. Shelf portion 30b provides a flat surface and its
length, preferably, is generally at least half the length of circuit breaker 26. Back-up
plate 32 is generally flat and rectangular shaped and as shown in Figure 3 has openings
which cooperate with openings in the two members of leg portion 30a of bracket
member 30 to receive screws 34,36 for securing bracket assembly 26 to sidewall 28
of circuit breaker 24, more about which will be discussed hereinbelow.
With particular reference to Figure 3, a base 42 of circuit breaker 24
cooperates with a cover 44 to form a molded case as is well known in the art. With
particular reference to Figure 5, base 42 has an inner wall 46 spaced inwardly from
sidewall 28 to form a pocket 50. Inner wall 46 separates the pocket 50 from a cavity
48 containing the circuit breaker mechanism 51. As shown in Figure 5, pocket 50
receives plate 32 of bracket assembly 26 and is totally electrically isolated from the
cavity 48 of circuit breaker 24, and therefore, electrically isolated from the circuit
breaker mechanism 51.
Pocket 50 is made between sidewall 28 and inner wall 46 along a
peripheral edge of base 42 as shown in Figure 5 and is accessed from underneath
base 42 for insertion of plate 32 therein. Also, as shown in Figures 3 and 4,
sidewall 28 has several spaced apart slots 52,54,56, which as mentioned hereinabove
were used to mount the terminal block assembly 10 of the prior art of Figures 1A and
1B.
With reference to Figures 4 and 6, when bracket assembly 26 is mounted
to sidewall 28, aperture 38 of bracket member 30 provides access to slots 52,54,56,
and opening 40 in the shelf portion 30b of bracket member 30 provides access to
aperture 38. These slots 52,54,56 allow leads 53 from circuit breaker 24 to be drawn
through aperture 38 of bracket assembly 26. These wires 53 are electrically connected
to one of terminal block assemblies 58, 60, and 62 which are supported by shelf
portion 30b of bracket member 30. The terminal blocks provide connections for leads
(not shown) connected to an external electrical device, such as an auxiliary switch or
an alarm, respectively.
In mounting bracket assembly 26 to base 42, leg portion 30a of bracket
member 30 is placed against sidewall 28 of base 42, with aperture 38 of bracket
member 30 framing slots 52, 54, and 56, so as to leave slots 52,54,56 accessible.
Back-up plate 32 is inserted in the pocket 50 between inner wall 46 and sidewall 28 of
base 42 from underneath, as shown in Figures 3, 4 and 5, until its holes, one of which
is indicated at 32a in Figure 3, are aligned with those in sidewall 28 and with one of
the openings 55 (Figure 3) in bracket member 30, and screws 34,36 are inserted into
the aligned holes. The terminal block assemblies 58,60,62 are then mounted to shelf
portion 30b of bracket member 30, and the wiring 53 from base 42 is connected
thereto, the leads 53 being brought through slots 52,54,56 in sidewall 28 of base 42.
From this and as shown in Figure 5, it is appreciated that screws 34,36 remain outside
of the cavity 48 containing the circuit breaker mechanism 51. In view of this,
electrical isolation is maintained since back-up plate 32 is located in an electrically
isolated pocket 50 in the sidewall 28 of the molded base 42 of circuit breaker 24,
resulting in the bracket assembly 26 being electrically isolated from the circuit breaker
mechanism 51. Since the bracket assembly 26 is electrically isolated, bracket
member 30, back-up plate 32 and in particular screws 34,36 can be made of a metal,
such as steel.
The manner in which bracket assembly 26 is mounted to base 42 of
circuit breaker 24 allows a substantially long bracket member 30 for providing a
mounting surface for several terminal block assemblies 58,60,62 to be fixedly secured
to base 42 without wobbling.
Whereas particular embodiments of the present invention have been
described for purposes of illustration, it will be appreciated by those skilled in the art
that numerous variations of the details may be made without departing from the
invention described in the appended claims.
In accordance with the patent statutes, I explained the principals and
operation of my invention and have illustrated and described what I consider to be the
best embodiment thereof.
What is Claimed is
WE CLAIM
1. A molded case circuit breaker comprising:
a molded case having walls forming a cavity including an outer
wall and an inner wall forming a pocket electrically insulated from said cavity;
a circuit breaker mechanism contained in said cavity;
terminal block means; and
a mounting bracket assembly for securing said terminal block
means to said molded case and comprising;
a mounting bracket on which said terminal block means
is mounted and having a leg portion bearing against said outer wall of said molded case
in alignment with said pocket;
a back-up plate received in said pocket; and
fastening means extending from said leg portion of said
mounting bracket through said outer wall and engaging said back-up plate in said
pocket.
2. The molded case circuit breaker of Claim 1 wherein said
fastening means is made of metal.
3. The molded case circuit breaker of Claim 1 wherein said back-up
plate is a metal plate with tapped holes and said fastening means comprise metal screws
engaging said tapped holes.
4. The molded case circuit breaker of Claim 3 wherein said
mounting bracket has a shelf portion extending outward from said leg portion and upon
which said terminal block means is mounted.
5. The molded case circuit breaker of Claim 4 wherein said leg
portion of said mounting bracket has an opening through which leads from said circuit
breaker mechanism pass to said terminal block means.
6. The molded case circuit breaker of Claim 4 wherein said molded
case has a first length, said mounting bracket has a second length at least about shelf
the second first length of said molded case and said terminal block means comprises
a plurality of terminal blocks, mounted on said half portion.
7. A mounting bracket assembly for mounting terminal block means
to a molded case circuit breaker having walls forming a cavity for a circuit breaker
mechanism and having an inner wall and an outer wall forming a pocket electrically
isolated from said cavity, said assembly comprising:
a mounting bracket on which said terminal block means is
mounted and having a leg portion bearing against said outer wall in alignment with said
pocket;
a back-up plate received in said pocket and
fastening means extending from said leg portion of said mounting
bracket through said outer wall and engaging said back-up plate.
8. The assembly of Claim 7 wherein said fastening means is made
of metal.
9. The assembly of Claim 7 wherein said back-up plate is a metal
plate having at least one tapped hole and wherein said fastening means comprises a
metal screw engaging said at least one tapped hole.
10. The assembly of Claim 7 wherein said mounting bracket has a
half portion extending outward from said leg portion and upon which said terminal
block means is mounted.
11. The assembly of Claim 10 wherein said leg portion has an
opening through which leads from said circuit breaker mechanism pass to said terminal
block means.
12. The assembly of Claim 11 wherein said shelf portion also has an
opening through which said leads pass.
13. A method of mounting terminal block means to a molded having
a cavity containing a circuit breaker mechanism, said method case circuit breaker
comprising the steps of:
forming said molded case circuit breaker with a pocket between
an inner wall and an outer wall, said pocket being electrically isolated from said cavity;
placing a mounting bracket against said outer wall in alignment
with said pocket;
inserting a back-up plate in aid pocket; and
passing fastening means from said mounting bracket, through said
outer wall and into engagement with said back-up plate in said pocket.
14. The method of Claim 13 wherein said step of passing fastening
means comprises passing metal fastening means through said outer wall and into
engagement with said back-up plate.
15. The method of Claim 13 comprising inserting a metal back-up
plate with tapped holes therein into said pocket and passing metal screws through said
outer wall and into engagement with said tapped holes in said metal back-up plate.

A plurality of terminal blocks are secured to a molded case circuit
breaker by a bracket assembly which includes a mounting bracket placed against a side
wall of the circuit breaker molded case. A back-up plate is inserted in a pocket formed
between the outer wall and an inner wall of the molded case and electrically isolated
from the cavity containing the circuit breaker operating mechanism. Fasteners extend
from the mounting bracket through the outer wall and engage the back-up plate. Since
the pocket is electrically isolated from the circuit breaker operating mechanism, the
back-up plate, and particularly the fasteners, can be made of metal for a solid, durable
connection.