U.S. patent application number 09/954117 was filed with the patent office on 2003-03-13 for fan blade sign display device.
Invention is credited to Liu, Meng Lin.
Application Number | 20030049124 09/954117 |
Document ID | / |
Family ID | 25494950 |
Filed Date | 2003-03-13 |
United States Patent
Application |
20030049124 |
Kind Code |
A1 |
Liu, Meng Lin |
March 13, 2003 |
Fan blade sign display device
Abstract
A fan blade sign display device includes a rotary device, an
actuator adapted to rotate the rotary device, a display unit
installed in the rotary device, and a control device adapted to
turn on/off the display unit. A sign is appeared in the movement
path of the LED array upon rotation of the LED array with the
rotary device at the speed in which the motion cycle of the LED
array is smaller than the transient retention time of visual
sensation when controlling the control device to turn on/off the
display unit.
Inventors: |
Liu, Meng Lin; (Panchiao,
TW) |
Correspondence
Address: |
PRO-TECHTOR INTERNATIONAL
20775 Norada Court
Saratoga
CA
95070-3018
US
|
Family ID: |
25494950 |
Appl. No.: |
09/954117 |
Filed: |
September 11, 2001 |
Current U.S.
Class: |
416/5 ;
416/61 |
Current CPC
Class: |
F04D 29/388 20130101;
F04D 29/384 20130101 |
Class at
Publication: |
416/5 ;
416/61 |
International
Class: |
F04D 029/00 |
Claims
What the invention claimed is:
1. A fan blade sign display device comprising: a rotary device; an
actuator adapted to rotate said rotary device; a display unit
installed in said rotary device; and a control device adapted to
turn on/off said display unit; wherein a sign is appeared in the
movement path of said LED array upon rotation of said LED array
with said rotary device at the speed in which the motion cycle of
said LED array is smaller than the transient retention time of
visual sensation when controlling said control device to turn
on/off said display unit.
2. The fan blade sign display device as claimed in claim 1 wherein
said actuator is a motor.
3. The fan blade sign display device as claimed in claim 1 wherein
said rotary device is a fan blade.
4. The fan blade sign display device as claimed in claim 1 wherein
said display unit is comprised of a LED (light emitting diode)
array.
5. The fan blade sign display device as claimed in claim 1 wherein
said control device is comprised of a power supply unit and a
driving unit.
6. The fan blade sign display device as claimed in claim 5 wherein
said power supply unit comprises a speed stabilizing circuit
adapted to control the speed of revolution of said rotary
device.
7. The fan blade sign display device as claimed in claim 1 wherein
said driving unit comprises software adapted to control on/off of
said display unit.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to electric fans and, more
particularly, to a fan blade sign display device, which comprises a
display unit installed in the fan blade to show a sign upon rotary
motion of the fan blade.
[0002] Electric fans are intensively used in summer to cause
currents of air for cooling or ventilating. Because electric fans
are inexpensive, household products distributors tend to use
electric fans as gifts to attract consumers. A regular electric fan
is comprised of a fan motor, and a fan blade coupled to the output
shaft of the fan motor. When switched on the fan motor, the fan
blade is rotated to cause currents of air. Because the speed of
revolution of the fan blade is high, it must be kept away from
touch of the hands. Therefore, regular electric fans commonly have
a grilled cover for protection. Nowadays, the fan blades of
electric fans are commonly injection-molded from plastics. In order
to attract the consumers, fan blade may be made transparent.
However, a child may not know the rotation status of the
transparent fan blade of an electric fan during its operation. When
a child inserts the fingers into the grilled cover of an electric
fan by mistake during rotation of the fan blade, the fingers will
be cut or severely injured by the fan blade.
SUMMARY OF THE INVENTION
[0003] It is one object of the present invention to provide a fan
blade sign display device, which gives a warning sign upon rotary
motion of the fan blade, preventing children from touching the fan
blade. It is another object of the present invention to provide a
fan blade sign display device, which produces a visual display
signal for advertising upon rotary motion of the fan blade. To
achieve these and other objects of the present invention, the fan
blade sign display device comprises a rotary device, for example,
the fan blade of an electric fan, an actuator, for example, a fan
motor adapted to rotate the rotary device, a display unit installed
in the rotary device, and a control device adapted to turn on/off
the display unit. A sign is appeared in the movement path of the
LED array upon rotation of the LED array with the rotary device at
the speed in which the motion cycle of the LED array is smaller
than the transient retention time of visual sensation when
controlling the control device to turn on/off the display unit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a front plain view showing an LED array installed
in a fan blade according to the present invention.
[0005] FIG. 2 is a speed control block diagram of the present
invention.
[0006] FIG. 3 is a block diagram of the LED array control circuit
according to the present invention.
[0007] FIG. 4 is a circuit diagram of the present invention.
[0008] FIG. 5 is a LED array control time series diagram according
to the present invention.
[0009] FIG. 6 is a schematic drawing showing an application example
of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0010] Referring to FIG. 1, a fan blade sign display device 1 is
installed in an electric fan's movable part (the blade) 2. When the
activator (fan motor) 3 rotates the movable part 2, the fan blade
sign display device 1 drives the LED array 13 thereof to flash,
producing visual signal. Due to the effect of transient retention
of visual sensation, the sign of the visual signal is retained in
the human brain for about 40 ms. Therefore, the viewer sees a
continuous stable sign displayed on the movable part 2.
[0011] Referring to FIGS. from 2 through 6, the fan blade sign
display device 1 is comprised of a power supply unit 11, a driving
unit 12, the aforesaid LED array 13, and the aforesaid actuator 3.
The power supply unit 11 comprises a speed stabilizing circuit 111
adapted to control the speed of revolution of the actuator 3 at a
predetermined constant level, causing a sign to be appeared in the
movement path of the LED array 13 upon rotation of the LED array 13
with the movable part 2.
[0012] The driving unit 12 has software adapted to turn on/off the
LED array 13 and to drive the LED array 13 to flash.
[0013] The design of the LED array may be variously embodied. In an
example of the present invention, the LED array 13 is comprised of
seven LEDs adapted to show the sign of "E" upon rotary motion of
the movable part 2, and the speed of revolution of the actuator 3
is 2400 runs/minute. We decompose the sign into dot matrix, i.e.,
the sign "E" is a 5*7 standard dot matrix "E". Because the speed of
revolution of the actuator 3 is 2400 runs/minute, it takes 25 ms
per run. If we divide one run into 72 dots, one run can display 12
letters (72/(5+1)) maximum, in which the pitch is one dot, and it
takes 374 us to light up every dot. The control sequence of the
seven LEDs to show the sign of "E" is as shown in FIG. 5.
[0014] By means of the transient retention effect of visual
sensation, the sign is temporarily kept in the brain for about 40
ms. A continuous and stable picture is seen in the movement path of
the LED array 13 upon rotation of the LED array 13 with the movable
part 2 in case the motion cycle time of the LED array 13 is shorter
than the visual retention time.
[0015] Further, the sign can be a company logo, trademark, warning
letters or sign to keep children from touching the fan blade.
[0016] A prototype of fan blade sign display device has been
constructed with the features of FIGS. 1.about.6. The fan blade
sign display device functions smoothly to provide all of the
features discussed earlier.
[0017] Although a particular embodiment of the invention has been
described in detail for purposes of illustration, various
modifications and enhancements may be made without departing from
the spirit and scope of the invention. Accordingly, the invention
is not to be limited except as by the appended claims.
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