Terminal structure of switch

Details Terminal structure of switch Terminal structure of switch

2000-02-14

2001-07-03

Gellner, Michael L. (Department: 2832)

Electricity: circuit makers and breakers

Combined with or actuated by connector coupling

Multiple circuit control, selective

C200S447000

Reexamination Certificate

active

06255608

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a terminal structure of a switch to be applied to a molded case circuit breaker, an electromagnetic contactor etc.
2. Description of the Related Art
The assembled structure of a conventional switch (for three-phase) which is applied to the aforesaid molded case circuit breaker is shown in FIG.
4
. In the figure, a reference numeral
1
denotes a casing (resin casing) of three-divided structure formed by combining an upper cover
2
, an intermediate cover
3
and a lower cover
4
in a fitting manner. A reference numeral
5
denotes a fixed contact shoe incorporated in the breaker portion of the casing
1
,
6
a movablecontact shoe,
7
an arc-extinguishing plate,
8
a switching mechanism,
9
an operation handle and
10
an over current tripping device. A terminal portion
11
on power supply side and a terminal portion
12
on load side are formed at the front end and the rear end of the casing
1
, respectively. The terminal portions
11
and
12
are provided with terminal conductors
13
and
14
drawn from the inner portion of the casing at every phase and also provided with terminal screws
15
engaged with the terminal conductors
13
and
14
, respectively. Each of the terminal portions is partitioned at every phase by partition walls formed at the casing
1
. Each of the terminal conductors
14
of load side is integrated with the fixed contact shoe and fixedly held at the intermediate cover
3
in a bent configuration of S-shape as shown in
FIGS. 2A and 2B
. In
FIGS. 2A and 2B
, a reference numeral
14
a
denotes a fixed contact,
14
b
an arc horn and
14
c
a wire connection portion drawn to the terminal portion
12
.
The conventional structure of the upper cover
2
of the aforesaid cover
1
and the intermediate casing
3
which supports the terminal conductors
14
of load side are shown in
FIGS. 5A and 5B
. That is, the intermediate cover
3
is provided with partition walls
3
a
which elect upward so as to surround the wire connection portions
14
c
of the terminal conductors
14
of the respective phases drawn to the terminal portion and the terminal screws
15
(see FIG.
4
). The terminal portion of the power supply side is configured in the same manner.
The intermediate cover
3
is also provided with terminal fixing grooves
3
b
which are formed at the right and left walls of the drawing path of each of the terminal conductors
14
of load side so as to extend along the drawing path, respectively. Each of the terminal conductors
14
is fixed to the intermediate cover in a manner that a lug portion extended from the left and right side edges of the terminal conductor
14
(the width of the conductor of the lug portion is W) is pressed into the corresponding terminal fixing grooves
3
b
from the forward direction and fixed and held at the assembling position. In the example shown in the drawings, the groove width of the terminal fixing groove
3
b
corresponds to the plate thickness T of the terminal conductor
14
shown in FIG.
2
A, and the length of the terminal fixing groove is set so as to coincide with the length R of the lug portion shown in FIG.
2
B.
The upper cover
2
is fitted and coupled on the intermediate cover
3
as shown in the drawings in a manner that, at this position, the side walls
2
a
of the upper cover
2
are overlapped on the outsides of the partition walls
3
a
elected from the left and right ends of the intermediate cover
3
, respectively.
In a switch such as a circuit breaker or the like, it has been intended to increase the capacity while using the casing of the same frame size in order to miniaturize the size of the outer configuration, unify the type and reduce the managing processes of the designing and manufacturing procedures thereof. In this point of view, the conventional structure of the aforesaid terminal portion remains the following problems.
(1) According to the conventional switch, there has such a structure that the partition walls
3
a
elected upward from the intermediate cover
3
are respectively formed so as to surround the corresponding terminal conductors
14
drawn to the terminal portion for the respective phases and the upper cover
2
is fitted to the partition walls
3
a
from the outside. Accordingly, a space for inserting the wires into the terminal portion from the outside is limited by the partition walls. That is, the thickness of the side walls
2
a
and the partition walls
3
a
is required to be larger to some extent in order to secure the mechanical strength of the upper cover
2
and the intermediate cover
3
. However, in a case of setting the thickness of the side walls
2
a
and the partition walls
3
a
to predetermined values, respectively, so as to make the size of the entire outer configuration of the casing within a predetermined value, the width V
2
of a space for inserting a wire therein is inevitably restricted and becomes narrow.
Thus, when the casing having the conventional structure is still used, in a case where the casing for a switch with a smaller current capacity is also used as the casing for a switch with a larger current capacity, there arises a problem in use that a thick wire can not be inserted and connected from the outside.
(2) Further, although it is necessary to make the plate thickness of the terminal conductor larger in a switch specified to have a large current capacity, the terminal fixing grooves
3
b
of the intermediate cover
3
for fixing the terminal conductor
14
are arranged to have the same groove width along the entire length thereof in .he conventional casing. Accordingly, when the terminal conductor has a thickness larger than the groove width, the terminal conductor can not be pressed into and fixed to the terminal fixing groove
3
b
unless the terminal conductor is subjected to such a processing that the left and right side edges thereof are made flat, for example.
SUMMARY OF THE INVENTION
The present invention has been made in view of the aforesaid matters and an object of the present invention is to provide the terminal structure for a switch which can obviate aforesaid conventional problems and is improved so as to be able to cope with the enlargement of the specification of the rated current without changing the frame size thereof.
In order to attain the aforesaid object, according to a first aspect of the present invention, in the terminal structure of a switch which is arranged in a manner that a terminal portion whose respective phase spaces are partitioned by partition walls is defined at the end portion of a casing of three-divided structure formed by fitting an upper cover, an intermediate cover and a lower cover, a terminal conductor with a terminal screw drawn from a breaker portion within the casing is disposed at every phase in the terminal portion, and wires inserted into the terminal portion from outside are fastened by the screws to be coupled to the terminal conductors, respectively,
(1) a fitting portion of the upper cover and the intermediate cover is defined at a portion lower than an upper surface of the terminal conductors drawn to the terminal portion, and the terminal conductors drawn to the terminal portion and the terminal screws are surrounded by the partition walls formed at the upper cover.
As described above, since the walls for surrounding the terminal portion are formed only at the upper cover and the partition walls elected upward from the intermediate cover are eliminated, the space into which wires are inserted from the outside is enlarged as compared with the conventional double wall structure and hence thicker wires can be connected. As a result, the terminal structure according to the present invention can easily cope with the enlargement of the specification of the rated current without changing the frame size thereof.
According to a second aspect of the present invention, in the aforesaid terminal portion,
(2) left and right side edges of each of the terminal conductors laid between the terminal porti

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