Tools – Wrench – screwdriver – or driver therefor – Machine
Reexamination Certificate
1999-12-02
2001-09-11
Hail, III, Joseph J. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Machine
C081S056000
Reexamination Certificate
active
06286394
ABSTRACT:
BACKGROUND OF THE INVENTION
To reduce the time requirement for changing rolling mill rolls and similar components, the use of changeover apparatuses which are placed against the roll stand and make it easier to remove a component to be replaced and to insert a new component is known (EP-A-142 879). The invention is directed towards an arrangement which makes it easier to change a nut holding a roll ring on a cantilever-mounted roll shaft having a thread for the nut. This applies particularly to nuts which contain devices for the hydraulic clamping of the roll ring and are accordingly large and heavy and require precise handling (EP-B-343 440).
SUMMARY OF THE INVENTION
According to this, an arrangement for changing such a nut comprises a changeover apparatus which has a threaded sleeve which bears a thread that matches the thread of the roll shaft. This sleeve takes the nut to be placed on the roll shaft. The threaded sleeve is fitted with centring devices for placing it in alignment against the roll shaft. To ensure that the nut can be unscrewed from the sleeve and screwed onto the roll shaft, the sleeve is inhibited against rotation relative to the centring device and/or the roll shaft. For example, an anti-rotation device or frictional engagement can be provided between the sleeve and the centring device. The centring device as such is secured against rotation, for example by virtue of the fact that it is connected to supporting devices or by positive or frictional engagement with the roll shaft. To ensure that the nut can be readily unscrewed from the sleeve and screwed onto the roll shaft, it is necessary that the position of the sleeve thread relative to the shaft thread should be precisely matched. To avoid the design complexity associated with this matching process, the invention envisages that the threaded sleeve should be axially moveable in relation to the centring devices and/or the roll shaft. As soon as the nut reaches the shaft thread as it is unscrewed from the sleeve, this axial mobility of the sleeve allows it to assume the axial position which matches the shaft thread. The threaded sleeve is preferably axially moveable to ensure that rotational inhibition of the threaded sleeve will readily allow the nut to be unscrewed. However, it is also conceivable that the rotational inhibition should be provided by a friction force, the torque of which is higher than the torque exerted on the threaded sleeve as the nut is unscrewed. Instead of an axial movement, a rotary movement of the threaded sleeve is also possible.
The prior art provides many possible embodiments for the centring device. A particularly advantageous one consists in the centring device being formed by a changeover shaft which carries the threaded sleeve and can be clamped against the end of the roll shaft. The axial mobility of the threaded sleeve covers at least one unit of lead of the thread. Within the extent of its axial movement, it is expediently held by spring force in an initial position, from which the yielding movement which may be required when the nut thread strikes the shaft thread is possible. If the threads are designed in such a way that a correction of the axial position in each of the two axial directions may by chance become necessary, it is expedient, for example, that the threaded sleeve be urged by spring force into an initial position from which it can yield in both directions. In another embodiment, the arrangement is such that the sleeve is urged by spring force into an initial position at the shaft end of its travel and that when the centring device is placed against the shaft end, the thread end of the nut rests under this spring force against the thread end of the shaft, the sleeve yielding to a greater or lesser extent counter to this spring force.
The changeover apparatus according to the invention can be used profitably even when it is only a question of changing the nut. Generally, however, it is equipped to accept and change further components, in particular for changing further nuts and, if appropriate, roll rings. In this case, a plurality of nut changeover apparatuses is connected to one another in a geometrical relationship coinciding with a plurality of roll shafts by a framework which carries the said apparatuses. To enable the centring devices to assume their exact end position on the respectively associated roll shaft, despite positional tolerances, it is expedient if they are secured on the framework in such a way as to be axially moveable and axially preloaded by springs. The framework is then placed against the roll stand in such a way that the centring devices move onto the ends of the roll shafts under the spring preloading.
The changeover apparatus is not only provided for mounting but also for removing the rolling mill components. As regards the removal of the roll rings, it should be noted that, even after the nuts holding them have been released, they still stick very firmly on the roll shaft and must therefore be released, initially with very high forces, from this frictional engagement before they can be removed from the roll shaft with lower forces. To avoid the changeover apparatus having to supply the high forces required to release the frictional engagement of the roll rings, the invention envisages that a device for releasing the roll ring be provided on the roll shaft, this device expediently being formed as a piston/cylinder device on that side of the roll ring which is remote from the free end of the roll shaft. It is expedient if this forms part of a ring mounted between the roll ring and a collar of the roll shaft.
REFERENCES:
patent: 3128990 (1964-04-01), Brooks et al.
patent: 3425256 (1969-02-01), McGoogan et al.
patent: 3679173 (1972-07-01), Sherrick et al.
patent: 4438901 (1984-03-01), Reneau et al.
patent: 4581911 (1986-04-01), Shinomoto
patent: 4581956 (1986-04-01), Robert
patent: 4653304 (1987-03-01), Feldmann et al.
patent: 4706485 (1987-11-01), Gilvar et al.
patent: 4879927 (1989-11-01), Sevelinge
patent: 5964128 (1999-10-01), Kaneyama et al.
patent: 32 26 694 A1 (1984-01-01), None
patent: 35 15786 A1 (1986-11-01), None
patent: 0 142 879 A1 (1985-05-01), None
patent: 0 343 440 B1 (1989-05-01), None
Alix Yale & Ristas, LLP
Hail III Joseph J.
Thomas David B.
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