System employing semi-circular wheel for adjustably actuating electron page advancement

A page-turning means with adjustable speed comprises a retaining stage, a base plate having switch function, a spring means for providing rebounding force and a semi-circular wheel. The base plate has electronic circuit, connection terminal, and a plurality of elastic plates functioning as switch, and can accommodate the T-shaped spring means. The voltage level change resulting from the on-off state of the switches being sent to external controller through the terminals. The bottom end of the semi-circular wheel is connected to the base plate. The bottom of the semi-circular wheel is in contact to top end of the spring means. When the the semi-circular wheel is rotated by external force, one end portion of the spring means is suppressed to tough one or two elastic plate(s) and voltage of various levels is generated. A controller can output signal to control the page turning speed according to the generated voltage level.

FIELD OF THE INVENTION 
The present invention relates to a page-turning means with adjustable 
speed, more particularly, to page-turning means with easy operation and 
adjustable-speed feature. 
BACKGROUND OF THE PRESENT INVENTION 
The conventional page-turning operation can be executed by wheel rolling or 
key pressing, and the advantages and drawbacks of the two methods are 
discussed as follows: 
(1) Wheel-rolling method 
Advantage 
When executing page-up or page-down operation, the user only needs to use 
finger to touch one point on the rolling wheel and move it forward or 
backward. 
Drawback 
When executing continuously page-up or page-down operation, the user needs 
to move his finger to-and-fro continuously, and it is not convenient for 
user. 
(2) Key-pressing method 
Advantage 
The page-turning operation in uni-direction can be performed by simply 
pressing one finger on page-up or page-down key in keyboard. 
Drawback 
When the direction of page turning is changed, for example, from page-up to 
page-down and vice versa, the user needs to move his finger backward or 
forward with a large distance. This may be troublesome for user. 
Therefore, the object of the present invention is to provide a page-turning 
means with adjustable speed, by which the user can turn up or down pages 
easily and efficiently. 
To achieve the object, the present invention provides a page-turning means 
with adjustable speed, the user only needs to press on an upper portion of 
a semi-circular wheel and rotates the wheel forward or backward to a 
specific angle. The pages can be turned forward or backward continuously 
until the finger releases. During the operation, the finger of the user is 
kept on a specific point, therefore, the page turning operation is easy 
and efficient. 
The various objects and advantages of the present invention will be more 
readily understood from the following detailed description when read in 
conjunction with the appended drawings, in which:

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The page-turning means according to the present invention comprises a 
retaining stage 1, a base plate 2, a spring member 3 for providing a 
rebounding force, and a semi-circular wheel 4. More particularly, the base 
plate 2 (printed circuit board) is arranged on the top of the retaining 
stage 1. Two supporting poles 11 are arranged on both sides of the base 
plate 2. Each supporting pole 11 has been provided with a groove 12 on top 
thereof for the engagement of the shaft 41 of the semi-circular wheel 4. 
The base plate 2 has an electronic circuit comprising resistors R1-R3 and 
three terminals 25-27, elastic plates 21-24 functioning as switch, and a 
T-shaped spring member 3. As shown in FIG. 4, the voltage change caused by 
the switches 21-24 can be sent to the control IC through the terminal 26 
(27) of the base plate 2. As shown in FIG. 4, one end of the resistor R1 
is connected to power source V.sub.cc and first terminal 25, another end 
thereof is connected to the bottom of the spring member 3. One end of the 
resistor R2 is connected to the first elastic plate 21 and another end 
thereof is connected to the second elastic plate 22 and the second 
terminal 26, One end of the resistor R3 is connected to the third elastic 
plate 23, and another end thereof is connected to the fourth elastic plate 
24 and the third terminal 27. 
The bottom portion of the spring member 3 is soldered to the base plate 2 
such that two end portions 31, 32 of the spring member 3 are placed on the 
top of the corresponding elastic plates 21, 23. Therefore, the end portion 
31 (32) of the spring member 3 can be in contact with one elastic plate 21 
(23) or simultaneously with two elastic plates 21, 22 (23, 24) when being 
pressed. The top portion of the spring member 3 is in contact with the 
bottom of the semi-circular wheel 4, such that the spring member 3 can 
maintain the balance of the semi-circular wheel 4 when no external force 
is applied, and functions as the contact point of the switch means. Each 
of the front bottom and rear bottom side of the semi-circular wheel 4 is 
provided with a limiting means to limit the angle of forward or backward 
rolling of the semi-circular wheel 4. 
When the semi-circular wheel 4 is rotated forward by external force, the 
front portion 31 of the spring member 3 is forced to approach the elastic 
plates 21, 22. The front portion 31 of the spring member 3 will be in 
contact with the elastic plate 21 when the semi-circular wheel 4 is 
rotated to a first angle. At this time, with reference to FIG. 4, the 
circuit comprising R1, R2 is closed, therefore, a first voltage VZ1 is 
sent to a terminal Z1 of IC 5 through terminal 26. If the semi-circular 
wheel 4 is rotated further, the spring end portion 31 will be in contact 
simultaneously with the elastic plates 21, 22 and the resistor R2 is 
bypassed. Therefore, a second voltage VZ2 is fed into a terminal Z2 of IC 
5 through terminal 26. The control IC outputs a control signal of 
different page-turning speed. 
Similarly, when the semi-circular wheel 4 is rotated backward, different 
control voltage VZ2 is fed into IC 5 through terminal 27 to turn down the 
pages at different speed. 
Although the present invention has been described with reference to the 
preferred embodiment thereof, it will be understood that the invention is 
not limited to the details thereof. Various substitutions and 
modifications have suggested in the foregoing description, and other will 
occur to those of ordinary skill in the art. Therefore, all such 
substitutions and modifications are intended to be embraced within the 
scope of the invention as defined in the appended claims.