Turning – Lathe – With program control
Reexamination Certificate
2001-04-19
2003-06-17
Bishop, Steven C. (Department: 3722)
Turning
Lathe
With program control
C082S151000, C279S006000
Reexamination Certificate
active
06578456
ABSTRACT:
The invention relates to a machine tool for the turning of workpieces with eccentric sections, comprising a tool support movable in the direction of at least one axis, a workpiece spindle drivable for rotation about a spindle axis and comprising a workpiece chuck, in which the workpiece can be clamped with a variably adjustable eccentricity, wherein the workpiece chuck has a chuck housing, a collet actuation and a collet support arranged in the chuck housing and having a collet held thereon, this collet being adapted to be brought into concentric or eccentric positions relative to the spindle axis as a result of movement of the collet support relative to the chuck housing.
A machine tool of this type is known from the state of the art but, in this case, a stepless adjustment of the collet support relative to the chuck housing can be adjusted only manually, in particular, using measuring tools for the exact determination of the eccentricity of the respective adjustable position.
The object underlying the invention is therefore to improve a machine tool of the generic type in such a manner that the adjustment of the collet support relative to the chuck housing can be brought about more simply.
This object is accomplished in accordance with the invention, in a machine tool of the type described at the outset, in that the machine tool has at least one axis controlled by a machine control, that an adjusting element is provided on the machine tool and this element can be moved towards the workpiece chuck for the adjustment of the respective adjustable position of the collet and can be brought into operative connection with a receiving means connected to the collet support and that in this operative connection between the adjusting element and the collet support the relative movement between the collet support and the chuck housing for the alteration of the adjustable position can be controlled by means of the machine control by way of the at least one controlled axis.
The advantage of the inventive solution is to be seen in the fact that with it it is possible to use the machine control, which is generally present in any case, to carry out the respective adjustable position of the collet relative to the chuck housing so that, on the one hand, the complicated manual adjustment can be dispensed with and, on the other hand, there is even the advantage that during a machining cycle a variation of the adjustable position is possible by means of corresponding specifications of the machine control.
This may be achieved particularly favorably when the adjusting element can be moved by the machine control relative to the receiving means in a direction of engagement which extends transversely to the direction of movement of the collet support relative to the chuck housing.
As a result of a direction of engagement extending in such a manner the adjusting element and the receiving means may be designed as interacting form-locking elements which can be brought into engagement with one another simply due to the movement in the direction of engagement in order to provide the connection between the adjusting element and the collet support.
In principle, the direction of engagement can always be aligned in different directions. In this respect, a solution which is particularly favorable with respect to the conditions in a machine tool provides for the direction of engagement to extend approximately parallel to the spindle axis.
In principle, it would be conceivable to move not only the collet support relative to the chuck housing during the adjustment of the adjustable position but, at the same time, to move the chuck actuation with it in order to be able to keep the workpiece clamped in the collet in an unchanged manner even during variation of the adjustable position.
This is constructionally complicated.
For this reason, one advantageous solution provides for the workpiece chuck to have an actuating element which can be actuated at least indirectly by the machine control and with which the collet actuation can be acted upon in the direction of a holding position of the collet still holding the workpiece in the collet.
This means that with this solution the clamping of the workpiece in the collet is not brought about in the customary manner, i.e., with the customary cocking cylinder since the forces applied by the cocking cylinder and normally required for a secure clamping during the machining are so great that an adjustment of the collet support relative to the chuck housing is no longer possible with any justifiable expenditure of force.
For this reason, the customary cocking cylinder is deactivated for the adjustment of the collet support relative to the chuck housing and only the collet actuation is acted upon in such a manner that the workpiece is still held by the collet in its position relative to the collet and is not released in it.
For example, it would be conceivable for this purpose to provide an additional cocking cylinder to the customary cocking cylinder as actuating element which is in a position to apply such a small clamping force which still allows the workpiece to be fixed in position in the collet but, at the same time, the collet support to also be moved relative to the chuck housing.
This solution is constructionally complicated. For this reason, a simplified solution provides for the actuating element to be actuatable due to action on the workpiece chuck from outside.
Such action on the workpiece chuck from outside can be brought about in the most varied of ways. For example, it would be conceivable to provide a separate actuating device outside the workpiece chuck which acts on the actuating element in a defined position of the workpiece chuck.
A simple possibility for realizing such an actuating device provides for this to be formed by the tool support so that the actuating element can be actuated by the tool support.
Since, in the inventive sense, the workpiece chuck must be acted upon in any case by means of the adjusting element in order to adjust the collet support relative to the chuck housing, a particularly preferred embodiment provides for the actuating element to also be actuatable by the adjusting element.
A particularly favorable solution provides for the actuating element to be arranged on the collet support and to be movable together with it during the alteration of the adjustable position relative to the chuck housing so that the actuating element co-migrates during the movement of the collet support relative to the chuck housing due to the adjusting element and thus can also be coactuated by the adjusting element.
Fundamentally, it would be conceivable for the adjusting element to act on the inventive workpiece chuck in two ways, namely, on the one hand, on the receiving means and, on the other hand, on the actuating element.
A solution which is particularly favorable from a constructional point of view provides for the actuating element to bear the receiving means for the adjusting element so that the adjusting element can come into operative connection with the receiving means in a particularly simple manner and, at the same time, can actuate the actuating element.
An expedient construction therefore provides for the actuating element to be movable in the direction of engagement of the adjusting element so that as a result of movement of the adjusting element in the direction of engagement an actuation of the actuating element is brought about at the same time in order to act on the collet actuation.
In this respect, it has proven to be particularly favorable from a constructional point of view when the actuating element is movable approximately parallel to the spindle axis.
With respect to the arrangement of the adjusting element on the inventive machine tool, the most varied of possibilities are conceivable. For example, it would be conceivable to provide a separate moving device for the adjusting element.
However, a solution which is particularly favorable from a constructional point of view provides for the adjusting element to be held on the tool s
Bishop Steven C.
Index-Werke GmbH & Co. & KG Hahn & Tessky
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