Terminal device

Details Terminal device Terminal device

1998-02-13

2001-02-27

Abrams, Neil (Department: 2839)

Electrical connectors

Metallic connector or contact having movable or resilient...

Screw-thread operated securing part

C439S782000

Reexamination Certificate

active

06193566

ABSTRACT:

TECHNICAL FIELD
The present invention relates to terminal devices use in electrical equipment including control equipment such as push buttons, selector switches, indicator lamps and the like, or terminal devices with a built-in transformer adaptable or the like for use in said control apparatus.
BACKGROUND ART
A prior art push-button switch is shown in
FIG. 1. A
contact section
102
is coupled in back of a push button operation section
101
, wherein this contact section
102
is provided with terminal metal fixtures
103
,
103
electrically connected to a fixed contact and a movable contact, and washer-attached terminal screws
104
,
104
as mated therewith.
Also, a prior known transformer-attached indicator lamp is shown in
FIGS. 2 and 3
. A transformer section
122
is coupled in back of an indicator section
121
, and a terminal section
123
is coupled in further back of it. As shown in
FIG. 3
, terminal fixtures
124
,
125
electrically connected to the primary winding of a transformer are provided at the right and left sides of a substantially square back surface and symmetrical with respect to the center point, wherein terminal screws
126
,
127
are disposed at diagonally opposing corners for being mated with threaded holes of the terminal fixtures
124
,
125
. These terminal screws
126
,
127
are provided to be rotatable relative to square washers
128
,
129
but not detachable therefrom, and also arranged so that the terminal fixture portions opposing such washers
128
,
129
are exposed from a terminal section housing.
In these prior art devices, where the terminal screw
104
of the contact section
102
or the terminal screws
126
,
127
of terminal section
123
are connected with ring-like contact-bonding terminal-attached lead wires by way of example, it is required that the terminal screw
104
or screws
126
,
127
be completely unlocked for release and then mated again. This would result in an increase in wiring process step number while simultaneously raising a risk of occurrence of electrical shorting of circuitry at drop-out portions due to missing of terminal screws and/or dropping down thereof, which disadvantageously serves to further increase difficulty in screwing the washer-attached terminal screws into corresponding terminal fixtures when sufficient spaces are not present near or around them.
Seeing the prior art technology as to terminal base plates for mere connection between lead wires by extending the technical field, Japanese Patent Publication No. 4-11988 or Japanese Utility Model Registration Publication No. 3-7031 discloses therein a terminal base having terminal fixture with a vertical piece integrally provided therewith and a coil spring (recovery spring) as disposed between the distal end of such vertical piece and a housing.
When the automatic recovery structure of such terminal bases is adapted for use with terminal devices as employed in control elements such as push button switches and the like, positioning of the coil spring at the lower part of the vertical piece requires use of certain space corresponding to the length of coil spring compressed, which results in an increase in height of the contact section—in other words, the terminal section increases its depth dimension. This disadvantageously serves to much reduce the product value of control elements which have received strong demands for miniaturization. In addition, each coil spring must be laterally inserted during fabrication while forcing it to be compressed thus increasing complexity of assembly works, which in turn renders difficult automation of assembly.
The above Japanese Utility Model Publication No. 3-7031 also discloses therein another terminal base structure which includes a compression coil spring as provided on the front side (terminal screw side) of a terminal fixture, and an insertion section for support of the center portion of such coil spring, which section is arranged to penetrate through the terminal fixture from the front to the back side thereof thereby supporting an associated terminal screw.
However, the automatic recovery structure of this terminal base is faced with problems which follow: Where this device is adapted for use in controller elements, resultant structure is increased in total depth dimension due to the fact that the insertion section projects toward the back side of the terminal fixture when a terminal screw is locked; furthermore, a connection lead wire or contact-bonding terminal can be accidentally clipped between adjacent twisted wires of the coil spring due to exposure of the coil spring on the surface of such terminal fixture.
A further terminal base is disclosed in Published Unexamined Japanese Utility Model Registration Application No. 2-27666, which base is structured as shown in
FIG. 4
, wherein a washer guide section
112
is provided by bending downwardly a lower vertical elongate piece formed at one side of a washer supporting at its neck section a terminal screw
110
and is arranged to penetrate a terminal fixture
111
from its upper to lower side. The the coil section of a torsion coil spring (recovery spring)
114
is attached for support of spring
114
to each shaft
113
formed beneath the terminal fixture with its one free edge being engaged with the lower end of washer guide section
112
.
The prior art suffers from a problem in that when the automatic recovery structure is adapted for use in terminal devices as employed in controller elements such as push button switches and the like, assembly works are difficult rendering automation likewise difficult due to the necessity of attaching the coil section of each torsion coil spring
114
to its associated shaft
113
and then engaging it with the lower end of the washer guide section
112
while pushing the torsion coil spring
114
for resilient displacement. Another problem is that the resulting depth size is enlarged since the torsion coil spring
114
is disposed beneath the terminal screw
110
and located on an extension line from the axis direction of terminal screw
110
.
In the recent years a finger protect structure is increasing in importance more and more for use in control elements or control equipment. This refers to a specific structure for protection by use of dielectric materials to suppress an accidental finger touch in view of the fact that if electrically conductive then current-carrying portions such as head sections of terminal screws are exposed raising a risk of occurrence of electrical shocks.
One prior art approach to such finger protect structure is shown in
FIG. 5
by way of example, wherein a detachable finger protect cover
106
is attached onto a contact section main body
105
so as to cover terminal screws
104
. Another approach is depicted in
FIG. 6
, wherein finger protect pieces
108
,
108
are rigidly attached by adhesive so as to cover the head sections of terminal screws
104
,
104
of a contact section main body
107
. Unfortunately, any one of these approaches suffers from an increase in parts number as a whole; especially, the former approach of employing the finger protect cover
106
is associated with a problem in that the finger protect cover
106
can drop down and that attachment thereof might be forgotten after once taken out.
Accordingly, an object of the present invention is to provide a terminal device capable of avoiding the foregoing problems encountered with the prior art, more particularly a terminal device capable of easily attaining automatization based on the fact that while it has an automatic recovery structure for eliminating drop-down of washer-attached terminal screws while forcing them—when unlocked—to be automatically spaced apart from terminal fixtures, the device does not increase in depth size as a whole, and yet capable of being assembled merely by putting into a specified space without having to apply in advance pressure to a recovery spring during assembly.
DISCLOSURE OF THE INVENTION
A terminal device of this invention offers several features which follow.
(1) A term

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