Rotary shafts – gudgeons – housings – and flexible couplings for ro – Speed responsive device for adjusting relative rotational...
Reexamination Certificate
1999-10-26
2001-09-11
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Speed responsive device for adjusting relative rotational...
C464S160000, C464S087000
Reexamination Certificate
active
06287203
ABSTRACT:
BACKGROUND OF THE INVENTION
A. Field of the Invention
The present invention relates to a method and structure for coupling a step motor shaft, especially to a method and structure which can instantly increase the initial speed of the step motor for driving the load by traveling through a predetermined back-lash distance defined between the key of the shaft coupling device and the step motor shaft.
B. Description of the Prior Art
According to conventional technology, the structure of a step motor for driving a load via a shaft coupling device is illustrated in FIG.
1
. The shaft coupling device
11
is connected to a load (not shown) and mounted with a key
12
for connecting to the step motor shaft
13
. Since the step motor shaft
13
is secured to the shaft coupling device
11
, so the load will be driven by the step motor shaft
13
when the step motor shaft
13
rotates. Due to the resistance of the load, the initial speed for driving the load will be slow down and cannot instantly drive the load at a desired speed.
To increase the initial speed for driving the load, a conventional approach applies a clutch for progressively increasing the resistance of the load put onto the step motor. Another conventional approach uses an electronic speed controller for controlling the initial speed for driving the load in response to the moment of torsion. When the speed of the step motor is low, its moment of torsion is increased. In contrast, when the speed of the step motor is high, its moment of torsion is decreased. Accordingly, the initial speed for driving the load can be controlled by an electronic speed controller to be progressively increased. Eventually, the step motor can drive the load at a desired speed.
However, the mechanism for controlling the step motor by a clutch is complicated, which will inevitably increase the manufacturing cost. On the other hand, if the initial speed for driving the load is controlled by an electronic speed controller, the time and distance required for acceleration will be too long. Thus, for a step motor of low power, it would be desirable to improve its initial speed for driving a load using a simple mechanism.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a method and structure for coupling a step motor shaft which can instantly reach the desired speed when driving the load by providing a constant back-lash distance defined between the key of the shaft coupling device and the step motor shaft.
It is another object of the present invention to provide a simple method and structure for coupling a step motor shaft which is adaptable for a low-power step motor to reach the desired speed when driving the load.
In accordance with the present invention, a method and structure for coupling a step motor shaft is provided by forming a predetermined back-lash distance defined between the key of the shaft coupling device and the step motor shaft, thereby to instantly reach the desired speed when driving a load. According to a preferred embodiment of the present invention, the shaft coupling device is connected to a rotatable load. The shaft coupling device has a key which maintains a back-lash distance with a step motor shaft. Eventually, when the step motor shaft is not driving the load, they are not connected together. When the step motor shaft is driven by the step motor, it spins in a first direction and travels through a distance so as to leave a predetermined back-lash distance with the key. As soon as the back-lash distance is formed, the step motor shaft reverses its rotation direction and then starts to travel through the predetermined back-lash distance. The initial speed for driving the load soon increases as the shaft rotates in a second direction and its key approaches to the load to drive the load. At that moment, the desired speed for driving the load has already been reached. Consequently, the desired speed for driving the load will soon be reached.
REFERENCES:
patent: 5127316 (1992-07-01), Ishiwata
patent: 5226853 (1993-07-01), Courgeon
patent: 5836821 (1998-11-01), Yamada et al.
patent: 6106187 (2000-08-01), Mina
Chang Te-Chih
Chen Bill
Chen Emmet
Browne Lynne H.
Dunwoody Aaron
Mustek Systems Inc.
LandOfFree
Method and structure for coupling a step motor shaft does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and structure for coupling a step motor shaft, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and structure for coupling a step motor shaft will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2444234