Machine element or mechanism – Gearing – Interchangeably locked
Reexamination Certificate
2000-11-08
2002-09-17
Herrmann, Allan D. (Department: 3682)
Machine element or mechanism
Gearing
Interchangeably locked
C074S395000, C074S440000, C118S046000
Reexamination Certificate
active
06450053
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a device for ensuring correct tooth engagement during coupling of two gearwheels, more specifically, an adjustable first gearwheel to a second gearwheel of a printing-material-processing machine, the engagement-ensuring device comprising a first adjustment device for adjusting the first gearwheel in a direction towards the second gearwheel during coupling, and also comprising a protrusion and a guide for guiding the protrusion during coupling.
Such devices are necessary in order for decoupled gearwheels to be brought together into a precise position during coupling to form a gear train.
In a device corresponding to the general type mentioned in the introduction hereto and described in the published German Patent Application DE 42 26 392 C1, a spring bolt is arranged on a first gearwheel that is accommodated in a pivotable frame member, and a segment ring with a centering groove is arranged on a second gearwheel accommodated in a stationary frame member. Although the spring bolt is pivotable about an articulating joint connecting the pivotable frame member to the stationary frame member, it cannot be pivoted about the central axis of the first gearwheel because the spring bolt is fastened to the pivotable frame member by a link. Before coupling of the first gearwheel, the latter is arrested by a catch, and the second gearwheel is positioned more-or-less at a couple location by a machine drive. Thereafter, the pivotable frame member is pivoted, together with the first gearwheel, about the articulating joint in the direction of the stationary frame member, the spring bolt sliding in the centering groove and the rotatable second gearwheel being aligned relative to the arrested first gearwheel so that a given tooth of the first gearwheel is guided into a tooth gap of the second gearwheel, which is provided for the tooth. During the introduction of the given tooth of the first gearwheel into the tooth gap, the first gearwheel must be moved by the pivoting motion somewhat in the radial direction of the second gearwheel so that the so-called insertion direction of the given gearwheel corresponds thereto. The tooth has already passed into the tooth gap, and the gear train is thus closed, before the spring bolt has completely passed through the centering groove and enables a rotary movement of the second gearwheel again.
An unfavorable feature of the device described in the aforementioned German patent document is that, if a second gearwheel is not positioned sufficiently precisely in the coupling position, the spring bolt comes into contact with the segment ring and blocks further movement of the pivotable frame member relative to the stationary frame member, as a result of which the coupling operation is stopped. In this case, a renewed attempt to position the second gearwheel sufficiently precisely in the coupling position is necessary in order for the centering groove to be positioned precisely relative to the spring bolt.
For reasons explained hereinbelow, in so-called “long printing machines” with a large number of printing or varnishing units arranged in a row, such precise positioning of the second gearwheel is not always possible. The gearwheels of the impression cylinder of the printing or varnishing units are connected, via gearwheels of sheet-transporting drums, to form a continuous gear train. A given driving gearwheel of the gear train is connected to an electromotive central drive, which, via the gear train, rotatively drives each of the gearwheels of the gear train.
When the central drive is at a standstill, the driving gearwheel virtually cannot rotate. The greater the number of gearwheels located between the driving gearwheel and a driven gearwheel of the gear train, the more the driven gearwheel can be rotated when the printing machine is at a standstill. This results from each gearwheel pairing being affected by tooth clearance. The greater the number of gearwheel coupling locations provided between the driving gearwheel and the driven gearwheel, the greater the sum of the amounts of coupling-location tooth clearance, it being possible for the driven gearwheel to be rotated by that sum.
A gearwheel which is the farthest remote from the driving gearwheel in the gear train can thus be rotated by the greatest amount. For example, the gearwheel may have assigned thereto an impression cylinder of a varnishing unit arranged at the end of the printing machine and it may correspond to the second gearwheel described in the aforementioned German patent document and to be positioned in the coupling position.
Due to the sum of the amount of tooth clearance of the other gearwheels in the gear train up to the second gearwheel, it is not possible for the second gearwheel to be positioned reliably by the central drive, with the result that it is often the case that the spring bolt comes into contact with the segment ring, and position corrections are thus necessary.
A further disadvantage of the device described in the aforementioned German patent Document is apparent if the second gearwheel, to which the first gearwheel is to be coupled, is the driving gearwheel itself, which is connected to the central drive, or is a gearwheel in the gear train which is located in close proximity to the driving gearwheel. In this case, with the central drive at a standstill, the second gearwheel could only be rotated to a slight extent, if at all, because, between the central drive and the second gearwheel, there is too little total tooth clearance, if any at all, necessary for the rotation of the second gearwheel. In other words, absolutely precise positioning of the second gearwheel in the coupling position would be necessary for the centering groove to be centered precisely relative to the spring bolt. Even if the centering groove is offset slightly relative to the spring bolt, in which case the latter comes into contact with a beveling of the centering groove, coupling of the first gearwheel to the second gearwheel would not be possible because the spring bolt could not force the centering groove, and thus the second gearwheel, out of the rotary position secured by the central drive.
It is thus the case that the device described in the aforementioned German patent document is unsuitable not only for coupling the gearwheels of the varnishing unit which is arranged downline, as viewed in the printing-material transporting direction, of a large number of printing units, is thus remote from the central drive and is used, for example, for the concluding application of a clear protective varnish to a printed image, but also for coupling gearwheels of a varnishing unit which is arranged upline of a large number of printing units, is thus in the vicinity of the central drive and is used, for example, for the application of a zinc white primer to the printing material before the latter is printed in the printing units.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention thus to provide a device for ensuring correct engagement of a tooth of a first gearwheel in a second gearwheel, wherein the position of the second gearwheel within a gear train of a printing-material processing machine is not important for disruption-free coupling.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a device for ensuring correct tooth engagement during coupling of an adjustable, first gearwheel to a second gearwheel of a printing-material processing machine, comprising a first adjustment device for adjusting the first gearwheel in a direction towards the second gearwheel during coupling, and further comprising a protrusion and a guide for guiding the protrusion during the coupling, the protrusion being disposed eccentrically to one of the two gearwheels and being connected to the one gearwheel, so that, during rotation of the one gearwheel about a central axis thereof, the protrusion is rotatable together with the one gearwheel.
In accordance with another feature of
Friedrichs Jens
Heiler Peter
Kern Arno
Kropp Frank
Schaum Frank
Greenberg Laurence A.
Heidelberger Druckmaschinen
Herrmann Allan D.
Mayback Gregory L.
Stemer Werner H.
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