Plastic article or earthenware shaping or treating: apparatus – Female mold and charger to supply fluent stock under... – With means to close mold
Reexamination Certificate
1999-02-12
2001-03-27
Heitbrink, Tim (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Female mold and charger to supply fluent stock under...
With means to close mold
C425S451900, C425S595000
Reexamination Certificate
active
06206683
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a molding device for processing small, precision parts that present a light load and require high positioning accuracy for use in clean work environments and assembly lines.
Conventionally, hydraulic presses, crank presses that use a crank mechanism, and the like have been used as molding devices for processing small, precision parts that present a light load and require high positioning accuracy.
In addition to these types of presses, there have also been provided molding devices that use an AC servo motor to raise and lower a slide via a screw mechanism.
Furthermore, molding devices that use linear motors have also been developed. These devices take advantage of properties of linear motors such as high speed, high positioning accuracy, and efficient transfer of drive force involving quick acceleration and deceleration.
In conventional molding devices, a clamp press does not provide stable positioning accuracy for the bottom dead center of the slide due to thermal displacement and the like. With hydraulic presses, the use of oil, the installation space requirements, noise, and the like prevent their use in clean work environments.
With molding devices that use an AC servo motor as a drive source, it is a problem to provide high positioning accuracy. In addition, such devices raise safety concerns relating to power outages.
With molding devices that use a linear motor, the position at which the linear motor is attached to the guide device can result in the magnetic attraction from the linear motor applying a force to the guide device, which guides the raising and lowering of the molding head. This can cause a change in the gap between the magnetic plate and the movable slide of the linear motor, resulting in unstable thrust from the linear motor, deformation in the guide device leading to increased friction resistance that prevents smooth raising and lowering of the molding head, or the like.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a molding device which overcomes the problems described above.
It is a further object of the invention to provide a molding device that is highly accurate, and that has a positioning accuracy for the bottom dead center that is not affected by thermal displacement or the like. The present invention does not require a large installation space and can be used in clean work environments with limited noise and vibration. Positioning of the molding head during high-speed operations is reliable, and if power is lost during a power outage or when operations are stopped, the molding head is held reliably at a stopping position.
In order to achieve the objects described above, the present invention.
It is a still further object of the invention to provide multiple parallel molding devices which can be operated together or independently.
It is a still further object of the invention to provide multiple parallel molding devices on a common base, wherein the multiple molding devices are disposed between rails integrally projecting from the base.
The present invention provides a molding device that uses the thrust from linear motors including a magnetic plate and a movable slide to raise and lower a molding head guided by a guiding device disposed on a frame. Magnetic attraction between facing linear motors is canceled out by having two or more linear motors disposed facing each other separated by the molding head. The linear motors include either: a magnetic plate disposed toward the molding head and a movable slide disposed toward the frame; or a movable slide disposed toward the molding head and a magnetic plate disposed toward the frame. A guiding device is disposed to guide the raising and lowering of the molding head along a vertical direction perpendicular to the direction of magnetic attraction between the linear motors. The magnetic attraction from the linear motors is prevented from acting upon the guiding device.
The present invention can also provide a molding device as described above where the guiding device is formed as a linear roller guide, with at least two linear roller guides fixed on either side of the molding head. The linear roller guides include a guide rail and a roller unit, either with the guide rail disposed toward the molding head and the roller unit disposed toward the frame or with the roller unit disposed toward the molding head and the guide rail disposed toward the frame.
The present invention can also include a linear scale disposed to detect the position of the vertically moving molding head.
The present invention can also provide a molding device as described above where a counter-balancing device is disposed to balance the mass of the molding head, including an attached upper mold. This counter-balancing device can be formed from a spring device or an air-cylinder device.
The present invention can also include a support device disposed to support the vertically moving molding head at a stopping position when power to the molding device is shut off at the completion of an operation or due to a power outage. This support device can be formed as a spring-activated electromagnetically open device, a spring-activated air-pressure opening device, or a spring-activated oil-pressure device.
Briefly stated, the present invention provides two sets of linear motors fixed on opposed sides of a molding head driving device. Each linear motor includes a movable slider facing a casing. Each linear motor includes an armature plate movable adjacent a magnetic plate. The use of two linear motors cancels out the magnetic attraction between the facing linear motors. A linear roller guide is disposed vertically in a direction perpendicular to the magnetic attraction between the linear motors so that the magnetic attraction from the linear motors does not act on the linear roller guide. In another embodiment, three sets of molding head driving devices are disposed between left and right frames integrally formed projecting from a base to form a molding device. In a further embodiment a pair of double linear motors drives four molding head driving devices. The pair of double linear motors are affixed together by, for example, bolts.
According to an embodiment of the invention, there is provided a molding device comprising: at least two linear motors, the at least two linear motors facing each other separated by a molding head, a magnetic attraction between facing linear motors is canceled out by their positioning facing each other, the linear motors including a magnetic plate disposed toward one of the molding head and the frame, and a movable slide disposed toward the other of the molding head and the frame, a guiding device for guiding raising and lowering of the molding head along a vertical direction perpendicular to a direction of magnetic attraction between the linear motors, and the magnetic attraction from the linear motor is prevented from acting upon the guiding device.
According to a feature of the invention, there is provided a molding device comprising: a molding head, a guiding device for guiding the molding head in a linear direction, a molding head driving device, the molding head driving device including at least first and second linear motors, with one of the first and second linear motors fixed on each side of the molding head, each of the first and second linear motors including a movable slider and a magnetic plate, one of the movable slider and the magnetic plate being affixed to the molding head, and the other of the movable slider and magnetic plate being affixed to the molding head, a magnetic field of the magnetic plates in the first and second linear motors being oriented so that magnetic fields therefrom cancel at the guiding device, the guiding device being disposed vertically in a direction perpendicular to the magnetic attraction between the linear motors, the molding head driving device is formed in a modular structure so that the guiding device is not affected by the magnetic attraction between the linear mot
Itakura Hideo
Oyamada Yasuhiko
Takahashi Yuji
Tanaka Yasuhiko
Aida Engineering Co., Ltd.
Heitbrink Tim
Morrison Law Firm
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