Foldable transformer

Details Foldable transformer Foldable transformer

2001-06-27

2002-09-24

Vu, Hien (Department: 2833)

Electrical connectors

Connector movable between accessible and inaccessible positions

C439S174000, C320S111000

Reexamination Certificate

active

06454578

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to transformers for transforming high voltage, alternating current obtained from a conventional electrical power source to low voltage, direct current power, whereby a battery cell is electrically connected with the transformer and conveniently charged. In particular, the present invention relates to transformers having a plug for plugging into a power source outlet, wherein the plug is foldable so that the transformer can be compactly stored when not in use.
2. Description of the Prior Art
U.S. Pat. No. 5,401,178 discloses a conventional foldable transformer.
FIG. 4
of the attached drawings shows the transformer having a plug
50
, a pair of rotary pins
46
, and a pair of internal circuit connection means
48
. Each connection means
48
is pivotally connected via a pivot to a corresponding rotary pin
46
, such that each rotary pin
46
is pivotally foldable while maintaining constant electric connection with the connection means
48
. The plug
50
further includes a rotatable transverse rod
40
, an arcuate engaging block
36
, and a spring
38
. A concave pivot reception
44
is defined in each end of the rod
40
, for receiving a corresponding pivot. The rod
40
also has grooves
42
defined therein, and the block
36
also has a protruding engaging ridge
37
for engaging in the grooves
42
. A blind hole
39
is defined in an end of the block
36
opposite to the engaging ridge
37
, for receiving one end of the spring
38
. A substantially box-shaped storage cavity
32
is defined at a junction between a top surface and a front surface of an insulative enclosure
30
. The cavity
32
further has an electrical-connection opening
33
, and a pin hole
34
for receiving an opposite end of the spring
38
.
In assembly, each fixed pin
48
is inserted into a corresponding electrical-connection opening
33
. When the rotary pins
46
and rod
40
are rotated to an open position as indicated in
FIG. 4
, the spring
38
exerts force such that the ridge
37
firmly engages in the corresponding groove
42
. The pins
46
are thus securely held in position, allowing the plug
50
to be conveniently inserted into an AC power source outlet.
However, the plug
50
still has the following shortcomings.
1. Its structure has too many components, making it unduly complicated and difficult to manufacture.
2. The spring
38
is not a reliable component. The spring
38
cannot easily be uniformly mass produced, which causes the quality of various plugs
50
to not be uniform. Furthermore, repeated use of the plug
50
may reduce the resiliency of the spring
38
to the point where the spring
38
becomes dysfunctional.
Accordingly, an improved foldable transformer is required.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a plug for a foldable transformer that has a reduced number of components, is easily manufactured and assembled, and is reliable.
In a preferred embodiment, the present invention comprises an insulative enclosure and a plug. The plug is rotatably attached to the enclosure, and electrically connects an electronic circuit within the enclosure with an external power supply. The enclosure includes a storage cavity at the top end thereof. A pair of pin holes is defined in the enclosure at a rear of the cavity. A pair of parallel slots is defined in the enclosure between the pin holes. An arcuate engaging block is integrally formed on a bridge of the enclosure between the slots, by plastic injection. The plug includes a transverse rod, and a pair of rotary pins at opposite ends of the rod. Each rotary pin is pivotally and electrically connected via a pivot to a fixed pin. Each fixed pin is fixed within the corresponding pin hole, and is electrically connected to the electronic circuit. In a folded position, the rotary pins are accommodated entirely within the cavity. A groove defined in the rod engagingly accommodates the engaging block. The rotary pins are manually rotated outwardly from the cavity. The engaging block is released from the groove by the rod pressing against the engaging block and thereby elastically deforming the bridge. The rotary pins are rotated out to an unfolded position where they are perpendicular to the enclosure, and in which another groove defined in the rod engagingly accommodates the engaging block. The rotary pins are then ready to be inserted into a power source.
Other objects, advantages and novel features of the present invention will be drawn from the following detailed embodiment of the present invention with attached drawings, in which:


REFERENCES:
patent: 5220152 (1993-06-01), Doran
patent: 5401178 (1995-03-01), Liu
patent: 5494449 (1996-02-01), Chioo
patent: 6089886 (2000-07-01), Mareno
patent: 6275002 (2001-08-01), Chen

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