Sewing – Special machines – Positionable work carrier
Reexamination Certificate
2000-03-22
2001-12-18
Nerbun, Peter (Department: 3741)
Sewing
Special machines
Positionable work carrier
C112S155000
Reexamination Certificate
active
06330864
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to sewing machines, and in particular, to sewing machines having a drive device for moving a fabric-supporting frame in both the X-direction and the Y-direction, which is perpendicular to the X-direction.
2. Description of the Related Art
Many known drive devices for moving a fabric supporting frame include an X-drive mechanism and a Y-drive mechanism, each of which have a rotary motor, such as a pulse motor and a servo-motor, as a drive source. Therefore, a conversion mechanism is necessary to convert the rotary movement of the motor into a linear movement to move the frame in the X and Y directions. Such a motion conversion mechanism may include for example a belt and pulley mechanism, a wire and pulley mechanism or a ball-screw mechanism.
Another type of known device for moving a fabric supporting frame includes a linear motor as the drive source for the X-drive mechanism. However, the known sewing machines still require a rotary drive source and a motion conversion mechanism as the Y-drive mechanism in order to move the frame in the Y-direction. Thus, the Y-drive mechanism is the same as the above-described known devices. More specifically, the Y-drive mechanism of this type of drive device includes a belt and pulley mechanism that has a carrier mounted to a belt. The linear motor of the X-drive mechanism is supported on the carrier and has a movable member, to which a fabric supporting frame of a relatively small size is mounted. A representative example of such a sewing machine is described in Japanese Laid-Open Patent Publication No. 62-139693.
The incorporation of the motion conversion mechanism(s) complicates the construction of the drive device. In addition, due to the backlash among the mechanical parts of the motion conversion mechanism, it is difficult to improve the accuracy of the frame driving control. Although a ball-screw mechanism may be incorporated as a motion conversion mechanism to improve the accuracy of the driving control, ball-screw mechanisms are generally expensive, which can increase the manufacturing cost of the drive device.
Further, in the known drive device incorporating the linear motor as the drive source of the X-drive mechanism, the Y-drive mechanism still requires a motion conversion mechanism, which may cause backlash among the mechanical parts or may increase the manufacturing costs of producing the sewing machine with a linear motor.
SUMMARY OF THE INVENTION
It is, accordingly, one object of the present invention to teach improved sewing machines, in which a fabric support frame can be moved without use of a motion conversion mechanism that converts rotary movement into linear movement.
According to the present invention, improved sewing machines are taught that include a drive device, which has linear motors as drive sources for moving a fabric support frame in both the X-direction and the Y-direction. As a result, a motion conversion mechanism is not needed to convert rotary movement of the motor into linear movement. Therefore, the drive device may have a relatively simple construction and the driving accuracy of the frame can be improved.
In a preferred representative embodiment, a movable member of the linear motor of the X-drive mechanism is connected to the frame such that the frame can move together with the movable member in the X-direction and can move relative to the movable member in the Y-direction. Similarly, a movable member of the linear motor of the Y-drive mechanism is connected to the frame such that the frame can move together with the movable member in the Y-direction and can move relative to the movable member in the X-direction. Therefore, the frame can move in the X-direction and the Y-direction by the X-drive mechanism and the Y-drive mechanism, respectively, without interference between the X-drive mechanism and the Y-drive mechanism.
Preferably, rollers are mounted on the movable members of the X-drive mechanism and the Y-drive mechanism so as to engages recesses formed in the frame in the Y-direction and the X-direction, respectively.
Other objects, features and advantages of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims.
REFERENCES:
patent: 4649837 (1987-03-01), Futsuhara
patent: 5408944 (1995-04-01), Hayashi
patent: 5553545 (1996-09-01), Ono et al.
patent: 62-139693 (1987-06-01), None
patent: 274321 (1996-04-01), None
Lyon & Lyon LLP
Nerbun Peter
Tokai Kogyo Mishin Kabushiki Kaisha
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