Metal working – Plural diverse manufacturing apparatus including means for... – With turret mechanism
Reexamination Certificate
2000-04-28
2001-08-21
Briggs, William (Department: 3722)
Metal working
Plural diverse manufacturing apparatus including means for...
With turret mechanism
C029S03300H, C029S039000, C029S04850R, C408S035000
Reexamination Certificate
active
06276035
ABSTRACT:
BACKGROUND OF THE INVENTION
a) Field of the Invention
The invention relates to a tool-changing device comprising a rotatably mounted tool carrier having at least two tools, which tool carrier can be swivelled into the respective working position for a tool by means of a swivel drive.
b) Description of the Related Art
DE-C-39 29 136 discloses a tool-changing device of this type.
Tool-changing devices of this type, which are also called tool turrets, have been known for a long time. Since such tool-changing devices have a large mass, in particular if they are prepared for a larger number of tools and possibly for driven tools, high torque is required at the swivel drive in order to swivel the tool-changing device from one working position into a further working position in which another tool is used. In order to amplify the effect of the motor, the use of a gear unit is therefore necessary in order to provide the requisite torque for a high rotary acceleration. On account of the high loading and the high operating frequency, mechanical gear units are subjected to high wear and in addition to that require a large amount of space. In addition, the feeding of drive energy to the driven tools and the feeding of coolants cause difficulties, since further space is required for this.
OBJECT AND SUMMARY OF THE INVENTION
The primary object of the invention is to design a tool-changing device in such a way that mechanical intermediate members, e.g. gear units, are dispensed with and the transmission of drive energy and other supply media to the tools is simplified with reduced space requirement.
In a tool-changing device of the type mentioned at the beginning, this object is achieved according to the invention in that the tool carrier is connected to a hollow shaft in a rotationally locked manner and is mounted such that it can be rotated by the latter, in that an electric ring motor, free from mechanical multiplication force-transmission elements, acts directly on the hollow shaft, and in that the hollow shaft has means for the drive and/or supply of the tools.
Ring motors of the type used here are synchronous motors having an electrical winding in the stator and many permanent magnets in the rotor. According to the invention, the rotor in this case is connected to a hollow shaft of very large diameter, as a result of which the ring motor, on account of its very large diameter required in this case, can exert very high torque on the hollow shaft, which is connected to the tool carrier in a rotationally locked manner and at the same time assumes the task of mounting the latter.
On account of the large inside diameter of the hollow shaft, means for the drive and/or supply of the tools can be accommodated without the need for additional space, as a result of which the previous, external arrangement of motors and transmission lines, which required considerable space, are unnecessary.
In order to be able to provide as large a cavity as possible in the hollow shaft for the drive means and/or other supply means on the one hand and yet keep the outside diameter of the tool-changing device small on the other hand, provision is made in a further design for at least part of the shell of the hollow shaft to be formed by the rotor of the ring motor. The hollow shaft is either interrupted, in which case at least part of the shell is formed by the rotor, so that the latter is not arranged on the hollow shaft but inside the shell of the hollow shaft. However, the hollow shaft as a whole may also form the rotor.
However, it also possible for the rotor of the ring motor to be arranged on the shell of the hollow shaft.
In tool-changing devices of the type mentioned at the beginning, the tool carrier is normally held in the corresponding working position by a brake or a lock, for example in the form of serrations.
According to the invention, provision is made for the tool carrier to be capable of being positioned by electrical activation of the ring motor. Due to the high torque which such a motor can produce, it is not only possible to swivel the tool carrier quickly from one position into the other but also to hold it in a certain position without brakes and other mechanical locks.
A further advantageous design of the invention consists in the fact that the tool carrier is designed as an annular body, that the tools are arranged in the annular body, that a force-transmission device which can be coupled to the tools is arranged in the cavity enclosed by the annular body, and that the force-transmission device is connected to the means, arranged in the hollow shaft, for the drive of the tools. This results in an extremely compact and space-saving arrangement of the force-transmission device, which in view of its space requirement does not appear on the outside, since it is provided inside the cavity enclosed by the annular body of the tool carrier.
The means for the drive of the tools is advantageously a servomotor.
An advantageous design which advantageously develops the basic idea behind the invention may be seen in the fact that the force-transmission device is designed as an angle drive which has a central shaft which runs radially through the center of the cavity enclosed by the annular body, is mounted in a bearing cage supported such that it can be rotated relative to the hollow shaft and carries a bevel gear at its one end, this bevel gear meshing with a bevel gear driven by the servomotor, and carries a coupling at its other end, this coupling serving to connect the drivable central shaft to each drivable tool of the tool carrier. This angle drive is located in the center of the annular tool carrier. On account of its rotatable support relative to the hollow shaft, it is always in the state of rest, so that this angle drive does not constitute any increase in the tool-carrier mass to be accelerated.
A means for the supply of the tools may be at least one line for feeding coolant and/or energy. The line for the supply of tools may be arranged in the shell of the servomotor for the tool drive or in the shaft of the servomotor for the tool drive. However, it is also possible for the line for the supply of tools to be arranged between the shell of the servomotor and the hollow shaft.
The invention is explained in more detail below with reference to an exemplary embodiment.
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patent: 4920303 (1990-04-01), Perdriat
patent: 5341722 (1994-08-01), Tani et al.
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patent: 39 29 136 C1 (1989-01-01), None
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patent: 63-20130 (1988-01-01), None
English Abstract of DE 2128642.
English Abstract of DE 3817873.
English Abstract of DE 3133249.
English Abstract of DE 3929136.
Hessbruggen Norbert
Wernz Christoph
Briggs William
EMAG Maschinenfabrik GmbH
Reed Smith LLP
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