DE20107891U1 - Drive for a printing press - Google Patents

Abstract

The brake is constructed as a hydraulic pump (7), transferring liquid under pressure. A final wheel of the gear train is coupled to the hydraulic pump. The hydraulic pump is connected to an adjustable valve.

Description

[Utility model application]

MAN Roland Printing Machines AG Mühlheimer Strasse 341
63075 Offenbach
5

[Name of the invention] Drive for a printing machine

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[Description]

The invention relates to a drive for a printing press according to the preamble of claim 1.

[State of the art]

A large number of printing machines, and in particular sheet-fed offset printing machines, have gears on the printing unit cylinders and the cylinders involved in the printing material transport (transfer drums, turning drums, storage drums) that are connected to one another in pairs. A gear train formed in this way is driven at one or more points via intermediate gears and electric motors. It is important for register-accurate and doubling-free printing that the tooth flanks of the gears of the gear train lie against one another consistently, i.e. that there are no changes in the tooth flanks caused by the play in the gear train. This can be achieved in particular by feeding drive power to several points on the gear train, with the proportion of the drive torque fed in being precisely tailored to the existing conditions of the gear train. The disadvantage of such drives, however, is that several electric motors have to be used, which represents a major cost disadvantage, especially for smaller printing machines.

From DE 2 96 09 962 A1 a device for preventing a flank change between teeth of drive wheels of a printing machine is known, in which a clamping element that generates a braking torque is assigned to the driven cylinder. The braking torque generated by the clamping element can be adjustable.
30

Such a device results in one-sided tensioning of the gear train so that the drive wheels always lie on the same flanks. The disadvantage here, however, is that the device requires a

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represents a certain construction effort and, furthermore, the frictional heat generated by the constant braking torque must be dissipated.

DE 42 28 506 A1 discloses a drive for a printing machine with several printing units and a common gear train, in which a first drive motor feeds excess power into the gear train and this excess power is removed again by a last drive motor. The last drive motor thus functions as a brake.

The disadvantage of this drive solution is that several, or at least two, drive motors must be provided, which must be operated in the intended manner by an appropriate control system. This type of solution is not cost-effective, especially for small printing machines.

From DE 3 7 10 354 A1 and DE 32 0 0 064 A1, drives for multi-color sheet-fed rotary printing machines that include hydraulic devices are known. Here, one or more hydraulic motors are driven by a hydraulic generator, which in turn feed power into the gear train. Such a solution is complex due to the hydraulic generators and hydraulic motors and also cannot be used without further ado on high-speed printing machines. This solution is also not economically viable on small sheet-fed printing machines.

[Task of the invention]

The object of the present invention is therefore to expand a drive for a printing machine according to the preamble of claim 1 in such a way that a flank change between the teeth of the drive wheels is avoided while avoiding the disadvantages mentioned above.

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This object is achieved by the characterizing features of claim 1. Further developments of the invention emerge from the subclaims.

[Examples]

According to the invention, it is provided that at least one hydraulic brake is assigned to the drive, by means of which the drive power fed into the gear train at one or more points is compensated.

According to a preferred embodiment of the invention, the hydraulic brake is designed as a hydraulic pump driven by a pinion connected to a gear of the gear train. The oil pumped by the hydraulic pump in a circuit is preferably fed via an adjustable throttle so that the braking torque fed back into the drive gear train by the pump is adjustable. The hydraulic pump is preferably designed as a gear pump.

0 According to a preferred embodiment of the invention, it can be provided that the oil used to lubricate the printing press is used as the hydraulic fluid, which is collected in a collecting container under the printing press, filtered, pumped through the pump driven by the gear train, from there through the adjustable throttle and back into the collecting container for the lubricating oil. In particular, it can also be provided that the oil pumped by the pump is used to supply certain lubrication points on the machine.

According to a further development of the invention, the resistance caused by the pump and the throttle on the gear train is to be adjusted as a function of the engine speed.

To do this, it would be possible to adjust the Dros- ·**· · ······ · · ^· · · · · ·· J ! *!

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should be changed with the machine speed, for example to achieve a higher pressure and thus a higher braking effect at low speeds than at high machine speeds. This effect can also be achieved in a simple design by means of a pressure relief valve connected between the pump and the throttle. From a certain machine speed, the pressure relief valve releases oil, i.e. the oil pressure generated by the pump and thus also the braking torque are reduced or no longer increased with the speed.

Furthermore, an embodiment of the invention is explained with reference to the drawing.

This shows a gear train with drive motor and the braking device according to the invention.

Several drive gears 1 form a gear train 2, whereby the drive gears 1 belong to single or double-sized cylinders 0 of a printing press (not shown in more detail). The gear train 2 of the drive gears 1 is driven by an electric motor 4 via an intermediate gear 3. In the embodiment according to the figure, it is assumed that the printing material is transported from left to right.

A pinion 6 of a hydraulic pump 7 designed as a gear pump interacts with the last drive gear of the gear train 2 shown in the figure via an intermediate gear 5. The hydraulic pump 7 delivers oil from a collecting tank 10 via a line 8 via an adjustable throttle 9. In the line system 8, additional devices for cooling the oil delivered from the collecting tank 10 via the hydraulic pump 7 through the adjustable throttle 9 can also be connected.

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The oil pumped by the hydraulic pump 7 is preferably the lubricating oil of the printing press, whereby certain lubrication points of the printing press can also be supplied via the line system 8.

A pressure relief valve (not shown in the figure and preferably adjustable) can be connected between the hydraulic pump 7 and the throttle 9 via a T-piece in the line system 8.

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[List of reference symbols]

1 drive gear

2 gear train

3 Intermediate gear 4 Drive motor

5 Intermediate gear

6 pinion (hydraulic pump 7)

7 Hydraulic pump

8 Pipeline system

9 Throttle (adjustable)

10 collection containers

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Claims (9)

1. Drive for a printing press, in particular a sheet-fed offset printing press, with drive gears forming a gear train, a motor feeding power into the gear train and a brake interacting with a drive gear, characterized in that the brake is designed as a hydraulic pump ( 7 ) through which a fluid can be conveyed under pressure. 2. Drive according to claim 1, characterized in that a throttle ( 9 ) is connected downstream of the hydraulic pump ( 7 ). 3. Drive according to claim 2, characterized in that the throttle ( 9 ) is adjustable. 4. Drive according to one of the preceding claims, characterized in that a fluid can be pumped out of a collecting container ( 10 ) and back into the collecting container ( 10 ) by the hydraulic pump ( 7 ). 5. Drive according to one of the preceding claims, characterized in that lubricating oil can be pumped through the hydraulic pump ( 7 ). 6. Drive according to claim 5, characterized in that lubricating oil can be pumped to intended lubrication points via the hydraulic pump ( 7 ). 7. Drive according to one of the preceding claims, characterized in that the hydraulic pump ( 7 ) is associated with a cooling device. 8. Drive according to one of the preceding claims, characterized in that a braking torque dependent on the machine speed can be generated on the gear train ( 2 ) by the hydraulic pump ( 7 ). 9. Drive according to claim 2, characterized in that a pressure relief valve is connected between the hydraulic pump ( 7 ) and the throttle ( 9 ).