Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
2000-03-21
2002-04-23
Walberg, Theresa (Department: 3742)
Pumps
Motor driven
Electric or magnetic motor
C165S080300, C416S24700A
Reexamination Certificate
active
06375440
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fan unit assembled as a single unit, a fan assembly having a fan case for housing the fan unit, and a product comprising this fan assembly.
2. Description of the Related Art
Fans are installed in a wide range of industrial and consumer products for moving air heated by heat sources inside the product to the outside of the product. More and more industrial products operate continuously all the day, and the ability to maintain and replace parts without turning the power off and with the product continuing to operate is desirable. Fans are no exception, and fans which can be replaced while the power supply to the product in which the fan is used remains on are needed. Continuous operation also shortens fan service life, thus increasing the opportunities for fan replacement. It is therefore also necessary to improve the safety and ease with which fans can be replaced.
FIGS. 37
to
39
show a typical fan unit,
FIGS. 37 and 38
being perspective views thereof from different directions, and
FIG. 39
being an exploded perspective view of the fan unit.
As shown in these figures, the fan unit
900
comprises a fan
910
, fan box
920
, printed circuit board
930
, LED
940
, and a plurality of screws
950
.
The fan
910
has a frame
911
and a fan blade
912
freely rotatable to the frame
911
. A mounting hole
913
is disposed at each of the four corners of the frame
911
.
The fan box
920
is typically formed by shaping sheet metal. A finger guard
921
preventing a finger from entering the fan is formed at the ventilation opening in the bottom or side as seen in
FIG. 38. A
cantilevered beam-shaped operating lever
922
is further disposed to the fan box
920
. When the fan unit
900
is housed in a fan case (not shown in the figures), this operating lever
922
prevents unintentional removal of the fan unit
900
from the fan case. It can also be operated so that the fan unit
900
can be removed from the fan case.
A control circuit (not shown in the figures) for controlling rotation of the fan blade
912
, and switching the LED
940
on/off, is provided on the printed circuit board
930
. Also provided thereon are a connector
931
for connection with the LED
940
, and a connector
932
for connection with the fan
910
motor (not shown in the figures). These connectors
931
,
932
are connected with the LED
940
and fan
910
(that is, the fan motor) by wiring not shown in the figures. As also shown in
FIG. 37
, a guard edge
933
protruding to the front of the fan unit when the fan unit
900
is assembled is also formed on this printed circuit board
930
. This guard edge
933
is inserted to a connector (not shown in the,figures) coupled to the printed circuit board
930
, and transfers power and signals therefrom to the printed circuit board
930
.
A plurality of screws
950
of a plurality of types are used to assemble this fan unit
900
.
As shown in
FIGS. 37
to
39
, a conventional fan unit thus comprised has a plurality of fan boxes
920
made from sheet metal, and is assembled using a large number of screws. Assembly is thus inefficient and costly.
The productivity of the process for housing this fan unit
900
into a fan case (not shown in the figures) and connecting a connector to the guard edge
933
of the printed circuit board
930
[
920
, sic] is also poor. There are also maintenance-related problems.
SUMMARY OF THE INVENTION
With respect to the aforementioned problems, it is therefore an object of the present invention to provide a fan unit that is easy to handle and reduces cost. A further object is to provide a fan assembly whereby fan unit maintenance and replacement are simple. Another object is to provide an apparatus (product) comprising a fan assembly of the present invention.
To achieve this object a fan unit according to the present invention comprises a fan, a fan housing frame, and a fan housing cover. The fan has a frame, a fan blade freely rotatable to the frame, and an installation member disposed to the frame. The fan housing frame has an opening on one side for disposing the fan internally thereto, a ventilation opening in the opposite side, and an engaging member formed on an inside wall for engaging the installation member of the internally disposed fan and thereby determining the fan position. The fan housing cover has a ventilation opening, and an engaging member on an inside wall for engaging the installation member of the fan internally disposed to the fan housing frame. The fan housing cover thus engages the fan housing frame so as to cover the opening into which the fan is installed, and in conjunction with the fan housing frame secures the fan in the fan housing frame.
With a fan unit of the present invention, a fan placed into the fan housing is positioned therein by inserting engaging protrusions (tabs and claws) of the fan housing frame and cover into corresponding holes. No screws are therefore needed to secure the fan in the fan housing. The fan housing cover is similarly engaged with the fan housing frame by means of matching tabs, claws, and holes, and no screws are therefore needed to secure the cover to the box frame.
A fan unit according to the present invention can thus be easily assembled without using any screws or tools such as screwdrivers, and thus helps reduce manufacturing cost.
The present fan unit further preferably has a finger guard formed to the opening of the fan housing frame from which the fan is not inserted (the bottom opening below); and a finger guard formed to the opening in the fan housing cover.
As shown in
FIG. 37
to
FIG. 39
, a fan unit according to the related art only has a finger guard on one side. This makes maintaining or replacing a fan while turning at high speed in the product in which it is used potentially dangerous. Safety can be improved, however, by providing a finger guard on both sides of the fan unit as per the present invention.
Yet further preferably, the fan housing frame and fan housing cover of a fan unit of the present invention are resin moldings.
In addition to helping reduce cost, using resin moldings assures that the box frame and cover are electrically isolated from the power source so that safety can be further improved when maintaining or replacing an operating fan.
The finger guard of a fan unit according to the related art as shown in
FIGS. 37
to
39
is made from sheet metal. The finger guard thus provides great resistance to air flow, and is the source of quite loud noise.
However, by molding the finger guard from resin, the finger guard can be shaped to produce little air resistance, and is thus effective as a way to reduce noise.
Yet further preferably, the fan unit comprises a printed circuit board having on one end a card edge for insertion to a connector, and having a control circuit mounted thereon for controlling fan blade rotation. The fan housing frame in this case also has an opening for passing the card edge of a printed circuit board disposed internally to the fan housing frame outside the fan housing to the front in a specific insertion direction orthogonal to the direction of air flow of air moved by the fan. The fan housing frame also has a retainer on an internal wall for holding a side of the printed circuit board disposed internally to the fan housing frame. The fan housing cover in this case further has on an internal wall a retainer for holding the printed circuit board side opposite the side held by the fan housing frame. In conjunction with the fan housing frame, the fan housing cover thus secures a printed circuit board disposed internally to said fan housing frame.
Similarly to a fan unit according to the related art as shown in
FIG. 37
to
FIG. 39
, a printed circuit board is preferably assembled into a fan unit of the present invention. In a fan unit of the present invention, however, the printed circuit board is held securely by the retainers provided on the fan housing frame in which the printed circuit board is installed and th
Armstrong Westerman & Hattori, LLP
Fujitsu Limited
Walberg Theresa
LandOfFree
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