Electrical transmission or interconnection systems – Miscellaneous systems – Power packs
Reexamination Certificate
2001-02-20
2003-03-18
Fleming, Fritz (Department: 2836)
Electrical transmission or interconnection systems
Miscellaneous systems
Power packs
C307S154000
Reexamination Certificate
active
06534885
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an adapter for a DC power source unit that converts AC voltage from a commercial power source into DC voltage, the adapter supplying the DC voltage to a cordless power tool.
2. Description of the Related Art
Battery packs normally include a plurality of 1.2V cells connected together to produce a voltage of 9.6V, 12.0V, 14.4V and the like, to match the rated voltage of a power tool. Because the number of connected cells varies with the type of battery pack, the different battery packs have different external shapes.
FIGS.
1
(
a
) to
3
(
b
) show examples of battery packs. FIGS.
1
(
a
) and
1
(
b
) are plan and side views, respectively, showing a battery pack
28
with eight 1.2V cells connected together to produce a 9.6V output. FIGS.
2
(
a
) and
2
(
b
) are plan and side views, respectively, showing a battery pack
29
with ten 1.2V cells connected together to produce a 12.0V output. FIGS.
3
(
a
) and
3
(
b
) are plan and side views, respectively, showing a battery pack
30
with twelve 1.2V cells connected together to produce a 14.4V output.
As shown in FIGS.
1
(
a
) and
1
(
b
), the 9.6V battery pack
28
includes a fitting portion
28
a
. The fitting portion
28
a
includes a protruding portion
28
b
and a groove
28
c
. The fitting portion
28
a
is adapted to fit into a battery holding space of a power tool (not shown) with a rated voltage of 9.6V (referred to as 9.6V power tool herein after). The battery holding space includes a groove portion that engages with the protruding portion
28
b
, and a protruding portion that engages with the groove
28
c
, when the fitting portion
28
a
is properly inserted into the battery holding space.
The 12.0V battery pack
29
shown in FIGS.
2
(
a
) and
2
(
b
) is provided with a fitting portion
29
a
. The fitting portion
29
a
includes a protruding portion
29
b
with the same shape as the protruding portion
28
b
of the battery pack
28
. Although not shown, a battery holding space of a 12.0V power tool is provided with a groove portion that engages with the protruding portion
29
b
when the fitting portion
29
a
of the battery pack
29
is properly inserted into the battery holding space.
When a user attempts to insert the 12.0V battery pack
29
into the 9.6V power tool, the upper end of the fitting portion
29
a
will abut against the protruding portion provided in the battery holding space of the 9.6V power tool, so that the fitting portion
29
a
can not be properly inserted into the battery holding space. Because improper 12.0V voltage will not be supplied to the 9.6V power tool, the life of the power tool will not be reduced by improper voltage supply. It should be noted that there is little risk of reducing the life of the 12.0V power tool by driving the 12.0V power tool using the 9.6V battery pack
28
. Therefore, the fitting portion
28
a
of the 9.6V battery pack
28
is configured so that it can be inserted into the battery holding portion of the 12.0V power tool.
Further, as shown in FIGS.
3
(
a
) and
3
(
b
), the 14.4V battery pack
30
includes an fitting portion
30
a
. The fitting portion
30
a
has a protruding portion
30
b
provided at a different position than of the protruding portions
28
b
,
29
b
of the battery packs
28
,
29
. Although not shown, the battery holding space of a 14.4V power tool is provided with a groove portion that engages with the protruding portion
30
b
when the fitting portion
30
a
of the battery pack
30
is inserted into the battery holding space of the 14.4V power tool.
With this configuration, when a user attempts to insert the 14.4V battery pack
30
into the 9.6V power tool or the 12.0V power tool, the protruding portion
30
b
of the battery pack
30
will abut against the lower edge of the battery holding space of the power tool, so that the fitting portion
30
a
can not be inserted into the battery holding portion. Similarly, when a user attempts to insert the 9.6V battery pack
28
or the 12.0V battery pack
29
into the 14.4V power tool, the protruding portion
28
b
or
29
b
of the battery packs
28
,
29
will abut against the lower edge of the battery holding space of the 14.4V power tool, so that the fitting portion
28
a
or
29
a
of the battery packs can not be inserted into the battery holding space.
Note that the battery packs
28
,
29
,
30
are formed with protruding portions
28
b
,
29
b
,
30
b
on only one side of the fitting portions
28
a
,
29
a
,
30
a
. With this configuration, the fitting portions
28
a
,
29
a
,
30
a
can not be inserted in the battery holding portions with polarities reversed, even into a power tool with the corresponding rated voltage.
The battery packs
28
,
29
,
30
are provided with latches
31
,
32
that engage with corresponding engagement portion (not shown) of the power tools, and fix the battery packs
28
,
29
,
30
in the, power tools, when the fitting portions
28
a
,
29
a
,
30
a
are properly inserted into the battery holding spaces of the power tools.
As shown in FIGS.
1
(
a
) to
2
(
b
), the 9.6V and 12.0V battery packs
28
,
29
both have a latch
31
with the same shape and provided at substantially the same position. A protrusion
29
c
is provided near the latch
31
of the battery pack
29
.
Although not shown in the drawings, the 9.6V and 12.0V power tools are provided with an engagement portion that engages with the latch
31
when the fitting portion
28
a
,
29
a
of the battery pack
28
,
29
is properly inserted into the battery holding space of a power tool that has a rated voltage that matches the output voltage of the battery pack
28
,
29
. The 12.0V power tool is also provided with a groove portion adjacent to the engagement portion that engages with the latch
31
. This groove portion matches the protruding portion
29
c
. With this configuration, the power packs
28
,
29
can be attached to the corresponding power tools.
Because the battery pack
29
is provided with the protruding portion
29
c
, even if the fitting portion
29
a
is somehow actually inserted into the battery holding space of the 9.6V power tool, the protruding portion
29
c
will abut against the lower edge of the power tool. This prevents the latch
31
and the engagement portion of the power tool from engaging together, so the battery pack
29
can not be properly mounted. It should be noted that it is possible to mount the 9.6V battery pack
28
into the 12.0V power tool.
As shown in FIGS.
3
(
a
) and
3
(
b
), the latches
32
of the 14.4V battery pack
30
are provided at two positions, both different from the latches
31
of the battery packs
28
,
29
. That is, the latches
32
are provided at two opposite sides of the battery pack
30
, whereas the latches
31
are provided at a single front surface of the battery packs
28
,
29
. Accordingly, the 14.4V power tool is provided with two engagement portions at opposing sides thereof, for engaging with the latches
32
when connected to the battery pack
30
.
Because the 14.4V battery pack
30
has latches
32
positioned at different locations than the latches
31
of either the 9.6V battery pack
28
or the 12.0V battery pack
29
, even if somehow the fitting portion
30
a
of the battery pack
30
is actually inserted into the battery holding space of the 9.6V power tool or the 12.0V power tool, the latch could not possibly engage with the engagement portion of the power tool, so the battery pack
30
could not be properly mounted. Also, even if the 9.6V battery pack
28
or the 12.0V battery pack
29
were somehow inserted in the 14.4 power tool, the latch
31
could not be engaged with engagement portion of the 14.4 power tool.
By designing the power tools and the battery packs
28
to
30
in this manner, the fitting portion of a battery pack can not be inserted into the battery holding space of a power tool when the battery pack has a larger or different output voltage than the rated voltage of the power tool. Also, a battery pack can not be pro
Nakagawa Atsushi
Nakayama Eiji
Takeda Takeshi
Fleming Fritz
Hitachi Koki Co,. Ltd.
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