GB1581451A

GB1581451A - Rotatable auxiliary gripper means in a printing machine

Info

Publication number: GB1581451A
Application number: GB2518377A
Authority: GB
Original assignee: Polygraph Leipzig Kombinat Veb
Current assignee: Polygraph Leipzig Kombinat Veb
Priority date: 1976-06-18
Filing date: 1977-06-16
Publication date: 1980-12-17
Also published as: SU697354A1; DE2718314A1; FR2354950A1; DD126254A1; FR2354950B3; DE2718314C2; CS201619B1

Description

(54) ROTATABLE AUXILIARY GRIPPER MEANS IN A PRINTING MACHINE (71) We, VEB KOMBINAT POLYGRAPH WERNER LAMBERZ LEIPZIG formerly known as VEB POLYGRAPH LEIPZIG KOMBINAT FUR POLYGRAPHISCHE MASCHINEN UND AUSTRUSTUNGEN, t 705 Leipzig, Zweinaundorfer Strasse 59, German Democratic Republic a corporation organised under the laws of the German Democratic Republic do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a rotatable auxiliary gripper means in printing machine comprising at least two sheet holding systems, each of which moves at an independent nonuniform speed.

An auxiliary gripper means has the function of transferring a sheet from a feed table to a gripper system of a cylinder or a drum in a printing machine. The sheet transfer may take place either in the resting position of the sheet or at a speed which is lower than the peripheral speed of the cylinder or drum.

United Kingdom Patent Specification No.

1368617 discloses a rotatable auxiliary gripper, at which two sheet holding systems, disposed at 180 to one another, are connected with one another. The diameter of the rotatable auxiliary gripper corresponds to the diameter of the succeeding drum which is equipped with a gripper system rotating uniformly at machine speed. The drive of the auxiliary gripper is effected by way of a Geneva wheel, so that on each switching step of the Geneva wheel it rotates further through 1800. It is disadvantageous in this arrangement that, for each sheet holding system of the auxiliary gripper, only 1800 of the machine cycle is available for the feed of the sheet to the machine so that 50% of the machine cycle constitutes an idle phase for the sheet holding system, which can be compensated only through high operating speeds with high accelerations. Thereby, high inertia forces arise, which influence unfavourably the registration result and thereby the quality of the printing product.

According to the present invention there is provided a rotatable auxiliary gripper means in a printing machine and comprising a rotatable body member and at least two sheet holding systems each provided with sheet holding means which are displaceable in a peripheral region on the rotatable body members, drive means to rotate the body member and means to oscillate each of the sheet holding systems independently of the or any other sheet holding system relative to the rotatable body member and synchronously with the rotation thereof.

The drive of the sheet holding systems may take place by way of either a cam linkage or a cam wheel stepping gear or, in accordance with another variant, by way of a Geneva wheel drive or a stepping gear or a spur gearing.

The sheet holding systems may comprise either clamping grippers or suction grippers.

The sheet holding systems may be mounted to oscillate either around a common axis of the auxiliary gripper or around a respective shaft which is arranged eccentrically to the axis of the auxiliary gripper.

The take-over of the sheet from the feed table by way of the sheet holding systems may take place either before or during the hand-over of the preceding sheet to the feed drum or cylinder, preferably rotating at machine speed, so that at least an entire operating cycle is available for the acceleration of the sheet to the speed of the feed drum or the cylinder. Thereby, the sheet may be accelerated slowly, whereby the arising forces are kept relatively small.

Embodiments of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a device for feeding sheets to a printing machine; Figure 2 shows a travel-time diagram relating to the device shown in Figure 1; Figure 3 shows drive means of the sheet holding systems by way of cam linkages; and Figure 4 shows drive means of the sheet holding systems by way of a can wheel stepping gear.

Referring now to the accompanying drawings, Figure 1 shows apparatus for feeding sheets to a printing maching. The apparatus includes a feed table 1, auxiliary gripper means 2 and a feed drum 3. The apparatus includes rotatable auxiliary gripper means comprising sheet holding systems 4 and 4' which are schematically illustrated mounted on a body member 2 of the auxiliary gripper means.

Auxiliary gripper body member 2 and the feed drum 3 have the same diameter.

In Figure 2, the angle of rotation of the sheet holding systems 4 and 4' is illustrated in dependence on the angle of rotation of the feed drum 3 in a displacement diagram.

U0 and Ul are the take-over and hand-over locations, respectively, of the sheet 5 by way of the sheet holding system 4 and 4' of the auxiliary gripper means. The drive of the sheet holding systems 4 and 4' takes place through non-uniformly translating gears.

Associated with each sheet holding system 4 and 4' in that case is a respective one of two gearings, which are similarly structured, so that only the construction of the gearing associated with one of the sheet holding systems 4 and 4' will be described below.

The drive means of the sheet holding system 4 and 4' includes as shown in Figure 3, a cam linkage, which comprises a control cam 7, a cam roller 8, a roller lever 9, a couplet member 10 and an output member 11, and which is associated with a similar compensating gear 12, 13, 14, 15 and 16. The rotatable auxiliary gripper means comprises means for imparting non-uniform speeds to each of the sheet holding systems. The compensating gear 12, 13, 14, 15 and 16 is illustrated for only one of the sheet holding systems 4 and 4'.

The sheet holding system 4 and 4' are connected to output members 11 of the respective cam linkages. The sheet holding system 4 and 4' each comprise a gripper clamping element 17, a gripper clamping element 18 and a gripper control roller 20 which contacts a gripper control cam 19. The cam roller 8 of the cam linkage 7,8, 9, 10 and 11 of both sheet holding systems 4 and 4' runs on a common control cam 7.

Another variant envisages connecting the sheet holding systems 4 and 4' to the coupler member 10 of the respective cam linkage 7, 8,9,10 and 11.

As illustrated in Figure 4, the drive of the sheet holding systems 4 and 4' takes place through a respective cam wheel stepping gear comprising a drive crank 24, a control cam 7.1, a cam roller 8.1, and a roller lever 9.1 with a toothed segment 21, which engages in a toothed wheel 22. The toothed wheels 22 are journalled to be independently rotatable about the axis 23 of the auxiliary gripper 2.

In Figure 4, both toothed wheels 22 are illustrated congruently. The sheet holding system 4 and 4', respectively, are each mounted on a lever firmly connected with the toothed wheel 22.

According to another arrangement (not illustrated) the auxiliary gripper means 2 comprises more than two sheet holding systems, such as the systems 4 and 4', and respective drive means is allocated to each of the sheet holding systems. The drive is also not restricted to the two examples described in the preferred embodiments, but can for example also include a stepping gear, a Geneva wheel gearing or a spur gearing. In place of the clamping grippers of the sheet holding systems 4 and 4' illustrated in Figure 3, the auxiliary gripper means 2 may be provided with suction strips or plunger grippers.

The mode of operation of the arrangement embodying the invention will now be described as follows: The aligned sheet 5 lying on the feed table 1 is taken over at the point UO by the sheet holding system 4 at v = O or v < V mad, is accelerated to machine speed, or to the speed of rotation of the feed drum 3, and handed over to the feed drum 3 at the point U1. The sheet holding system 4 at this point in time (Figure 1) is disposed at the point 50 to take over the sheet 6 from the feed table 1. The take-over of the sheet 6 takes place when the sheet 5 has not yet been conveyed completely from the feed table 1.

The sheet holding system 4 and 4' are each oscillatable independently of the other and with respect to the auxiliary gripper body 2, which is rotatable uniformly about the axis 23. The movement of the sheet holding systems 4 and 4' is effected through the superimposition of the movement of the auxiliary gripper 2, which rotates uniformly at half the speed of the feed drum 3, and the oscillating movement generated through the cam linkage 7, 8, 9, 10 and 11 (Figure 3).

The opening and closing motion of the gripper clamping element 18 is effected by way of the gripper control cam 19 and the gripper control roller 20.

According to the embodiment described with reference to Figure 4, the oscillating motion of the sheet holding system 4 and 4' is effected through the cam wheel stepping gear, wherein an additional motion is imparted from the stationery control cam 7.1 by way of the cam roller 8.1 to the toothed wheel segment 21, and transmitted by this to the toothed wheel 22 and thereby to the sheet holding systems 4 and 4'.

The sheet holding system 4 and 4' are mounted on the auxiliary gripper body 2 in such a manner that they execute an oscillatory motion around the axis of rotation 23 of the auxiliary gripper body member 2 or (not illustrated here) around a respective shaft which isjournalled eccentrically relative to the axis of rotation 23.

It is however also possible so to arrange the sheet holding systems 4 and 4' on the auxiliary gripper body member 2 that the respective sheet holding systems move relatively to one another in a straight line or on a coupling cam.

WHAT WE CLAIM IS: 1. A rotatable auxiliary gripper means in a printing machine and comprising a rotatable body member and at least two sheet holding systems each provided with sheet holding means which are displaceable in a peripheral region of the rotatable body member, drive means to rotate the body member, and means to oscillate each of the sheet holding systems independently of the or any other sheet holding system relative to the rotatable body member and synchronously with the rotation thereof.

2. A rotatable auxiliary gripper means as claimed in Claim 1, wherein each sheet holding system is oscillatable by a respective cam linkage system.

3. A rotatable auxiliary gripper means as claimed in Claim 1, wherein each sheet holding system is oscillatable by a respective cam wheel stepping gear.

4. A rotatable auxiliary gripper means as claimed in any one of the preceding claims, wherein each sheet holding means comprises clamping elements for gripping a sheet therebetween.

5. A rotatable auxiliary gripper means as claimed in any one of the claims 1 to 3, wherein each sheet holding means comprises suction elements for gripping a sheet.

6. A rotatable auxiliary gripper means as claimed in any one of the preceding claims, wherein each of the sheet holding systems is mounted to be rotatable about a common axis.

7. A rotatable auxiliary gripper means as claimed in any one of claims 1 to 5, wherein each sheet holding system is mounted to be rotatable about a respective shaft, each of the shafts being journalled eccentrically relative to the axis of rotation of the body member.

8. A rotatable auxiliary gripper means in a printing machine substantially as hereinbefore described with reference to Figures 1 to 3 of the accompanying drawings.

9. A rotatable auxiliary gripper means in a printing machine substantially as hereinbefore described with reference to Figures 1, 2 and 4 of the accompanyingn drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. relatively to one another in a straight line or on a coupling cam. WHAT WE CLAIM IS:

1. A rotatable auxiliary gripper means in a printing machine and comprising a rotatable body member and at least two sheet holding systems each provided with sheet holding means which are displaceable in a peripheral region of the rotatable body member, drive means to rotate the body member, and means to oscillate each of the sheet holding systems independently of the or any other sheet holding system relative to the rotatable body member and synchronously with the rotation thereof.