Printing – Rolling contact machines – Rotary
Reexamination Certificate
2003-03-17
2004-08-17
Yan, Ren (Department: 2854)
Printing
Rolling contact machines
Rotary
C101S375000
Reexamination Certificate
active
06776092
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a rotary lead-through assembly or bushing for supplying an operating fluid to a rotor of a machine for processing printing material. The rotor is provided with a rotor inlet opening, an operating cylinder formed with an expansion chamber, and a piston. The piston is provided with a piston outlet opening and is mounted so as to be displaceable towards the rotor. A pressure generator is connected both to the expansion chamber and to the rotor, when the openings are coupled with one another.
FIGS. 2 to 4 of German Patent DE 42 03 550 C2 show a rotary lead-through, the piston of which is mounted so as to be displaceable in radial direction with respect to the rotor. That rotor is a cylinder axle journal. A piston bore passing through the piston has a throttling effect, based upon which, when compressed air is supplied to the side of the piston facing away from the rotor, a positive pressure setting the piston against the rotating rotor is built up when compressed air is supplied to the side of the piston facing away from the rotor. While the piston is set against the rotor, the compressed air can escape into the surroundings through the piston bore, as long as the piston does not yet rest on the rotor. That leakage leads, on the one hand, to a reduced reaction speed of the piston and, on the other hand, to a noise nuisance, and presupposes that the pressure generator has a high capacity.
A further rotary lead-through or bushing, corresponding to the general type mentioned in the introduction hereto, is described in German Patent DE 42 10 009 C1 (note FIG. 1 thereof) wherein, when the rotor is at a standstill, the piston outlet opening is coupled to the rotor inlet opening by the piston being set against the rotor.
In the last-identified German Patent DE 42 10 009 C1, just as in the description of the invention of the instant application, the selection of the term “rotary lead-through assembly” is in no way intended to express the concept that the operating fluid is introduced into the rotor via the rotary lead-through while the rotor is rotating. Instead, the choice of the term is merely intended to express the concept that the operating fluid is introduced through the intermediary of the lead-through into a machine element that is mounted so as to be rotatable, in particular the rotor.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a rotary lead-through assembly or bushing for supplying an operating fluid to a rotor of a machine for processing printing material, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and with which leakage of the operating fluid is minimized.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a rotary lead-through assembly for supplying an operating fluid to a rotor of a machine for processing printing material. The rotary lead-through assembly comprises an operating cylinder including an expansion chamber, and a piston provided with a piston outlet opening. The piston is mounted so as to be displaceable towards the rotor for coupling a rotor inlet opening and the piston outlet opening with one another. A pressure generator is connected both to the expansion chamber and to the rotor, when the openings are coupled with one another. A threshold value valve is disposed between the expansion chamber and the piston outlet opening. The valve is automatically openable when a given threshold value of an excess pressure of the operating fluid is exceeded.
In accordance with another feature of the invention, the threshold value valve has a valve element. A valve spring serves for determining the threshold value and the valve element is loadable by the valve spring.
In accordance with a further feature of the invention, the valve element is mounted so as to be displaceable away from a valve opening of the threshold value valve under increasing tensioning of the valve spring.
In accordance with an added feature of the invention, the piston outlet opening is a circularly arcuate groove formed at one end of the piston.
With the objects of the invention in view, there is also provided a machine for processing printing material, comprising a rotor formed with a rotor inlet opening, and a rotary lead-through assembly for supplying an operating fluid to the rotor. The rotary lead-through assembly includes an operating cylinder having an expansion chamber, and a piston provided with a piston outlet opening. The piston is mounted so as to be displaceable towards the rotor for coupling the rotor inlet opening and the piston outlet opening with one another. A pressure generator is connected both to the expansion chamber and to the rotor, when the openings are coupled with one another. A threshold value valve is disposed between the expansion chamber and the piston outlet opening. The valve is automatically openable when a given threshold value of an excess pressure of the operating fluid is exceeded.
An advantage of the rotary lead-through assembly according to the invention is that even while the piston is being set against the rotor, no significant losses of the operating fluid occur. Consequently, the action of setting the piston in place occurs with very little noise, and the capacity of the pressure generator does not have to be particularly high. The high reaction speed of the piston when positive pressure is applied thereto is a further advantage, which results from the sealing of the piston by the threshold value valve during the act of setting the piston in place.
In a development which is advantageous with regard to minimizing the production costs, a valve element of the threshold value valve is loaded by a valve spring that determines the threshold value. For example, a reversing or check valve which can be obtained rather inexpensively from suppliers can be used as the threshold value valve. The function of the valve is not only for preventing the operating fluid from returning but, going beyond this, for letting the operating fluid through, i.e., opening, only when the precisely determined threshold value is exceeded.
The valve element and the valve spring are disposed in such a way that the valve element is mounted so as to be displaceable away from a valve opening of the threshold value valve under increasing tension or stress on the valve spring as the threshold value valve opens.
In a development which is likewise advantageous with regard to cost-effective production, the piston outlet opening is a circularly arcuate groove formed at one end of the piston. The rotor inlet opening and a further rotor inlet opening can have a different angular offset in relation to one another in different series of the machines for processing printing material. In all of these series of construction, provision can additionally be made for the rotor to be rotated over exactly the same rotational angle in order to decouple the rotor inlet openings from the piston outlet opening and, at the same time, to couple the other of the rotor inlet openings to the piston outlet opening. As opposed to a circular piston outlet opening, for example a circular bore, the circularly arcuate groove permits the same piston to be used for any of the series. The circular arcuate form of the piston outlet opening, as compared with a conceivable circular segment form, for example a semicircular form, of the piston outlet opening, offers the advantage that the portion of the area of the rotor which is overlapped by the piston outlet opening and lies beside the rotor inlet opening when the openings are coupled is comparatively small: Therefore, the compressive force is also comparatively small, which results from the action of the positive or excess pressure on the aforementioned portion of the area, and attempts to force the piston away from the rotor have to be overcome by the pressure generator.
The machine for processing printing material, which is equipped with the rotary lead-thro
Geider Andreas
Kündgen Rolf
Greenberg Laurence A.
Heidelberger Druckmaschinen AG
Mayback Gregory L.
Stemer Werner H.
Yan Ren
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