GB2151213A

GB2151213A - Sheet handling apparatus

Info

Publication number: GB2151213A
Application number: GB08430692A
Authority: GB
Inventors: Victor Hefftler; Peter Straube; Helmut Schone; Werner Kuhnert; Arndt Jentzsch; Horst Schulz
Original assignee: Polygraph Leipzig Kombinat Veb
Current assignee: Polygraph Leipzig Kombinat Veb
Priority date: 1983-12-12
Filing date: 1984-12-05
Publication date: 1985-07-17
Also published as: GB2151213B; FR2556327B3; DD223118A1; FR2556327A1; DE3436789A1; GB8430692D0; JPS60128148A

Abstract

To prevent a change in the position of the grippers (1.5) of sheet handling apparatus in circumferential direction on a gripper shaft (1.4) during closing operation of the grippers (1.5) within the bearing play of the shaft bearings, tensioning bearings are arranged to be displaceable in circumferential direction of a cylinder (1.1) in which the shaft and grippers are mounted. <IMAGE>

Description

SPECIFICATION Sheet handling apparatus The present invention relates to sheet handling apparatus. I In known sheet handling apparatus, several grippers are arranged on a drivable shaft mounted in gripper shaft bearings (German (Dem. Rep.) patent application No. WP B 41 F/246 658/0). In that case it is disadvantageous that it is impossible to avoid a change in the position of the grippers in the rotational centre on the shaft within the bearing play of the bearings due to reversal of the direction of the bearing force resulting from the forces present at the shaft during the closing operation of the grippers, and a register-true transfer of the sheets between two sheet handling apparatus is therefore not always achieved.

It would be desirable to prevent, as far as possible, the occurrence of a change in position of the grippers in circumferential direction in the rotational centre on the shaft during the closing operation of the grippers within the bearing play of the bearings.

According to the present invention there is provided a sheet handling apparatus comprising a rotary sheet conveying cylinder, a shaft mounted in the cylinder by a plurality of bearings, and a plurality of sheet gripper members mounted on the shaft and co-operable with sheet engaging means to grip sheets to be conveyed by the cylinder, the bearings comprising at least two spaced main bearings and a stressing bearing disposed between the two main bearings and arranged to be displaceable in the circumferential direction of the cylinder.

Preferably, the sheet engaging means comprises an abutment arranged in a channel extending in the cylinder parallel to the axial direction thereof, the shaft also being mounted in the channel and being rotatable about its axis to move the gripper members towards and away from the abutment. Rotation of the shaft can be effected buy a lever connected thereto and carrying a cam follower roller which is engaged with and displaced by a stationary cam track during rotation of the cylinder. Resilient means can be provided to maintain the roller in contact with the cam track and to urge the gripper members into their open position, i.e. a position in which they are spaced from the abutment.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Figure 1 is a schematic sectional view of sheet handling apparatus embodying the invention; Figure2 is a diagram showing the bending line and bearing forces of a gripper shaft of the apparatus due to gripper forces; Figure 3 is a diagram showing the bending line and bearing forces of the gripper shaft due to a roller lever force; Figure 4 is a diagram of the bearing forces in the case of bracing in circumferential direction; Figure 5 is a cross-section of the gripper shaft in a shaft bearing with the gripper opened; and Figure 6 is a view similar to Figure 5 but with the gripper closed.

Referring now to the drawings, there is shown part of sheet handling apparatus 1 comprising a sheet guiding or conveying cylinder 1.1 having a channel 1.2 in which a gripper abutment 1.3 is mounted.

Mounted on a shaft 1.4 and co-operable with the abutment 1.3 is a gripper 1.5, which is rotatable about the rotational centre or axis 1.6.

Also shown in Figure 1 are a holding force 2 acting in nearly one plane when the gripper 1.5 is closed, a gripper force 3 and a force 4.1 produced through a roller 4.

The bending lines 1.4.1, 1.4.2, 1.4.3 of the gripper shaft 1.4 produced by the different forces are schematically illustrated in Figures 2 to 4.

Figure 2 shows the shaft 1.4 mounted in bearings 5, the gripper forces 3 acting in the grippers 1.5 and the gripper bearing force 5.1 acting in the bearings 5.

The bending line 1.4.1 results from the forces 3 and 5.1.

Figure 3 shows the roller lever bearing force 4.2, which results from the torsion moments of the closed grippers 1.5 and acts through the shaft 1.4 (driven by the roller lever 4) and through the roller lever 4 in the bearings 5, as well as the bending line 1.4.2 of the shaft 1.4 resulting from the roller lever force 4.1.

The bending line of the shaft 1.4 in the case of a bracing of the shaft in circumferential direction 9 is illustrated in Figure 4. The shaft 1.4 is mounted in shaft bearings 5. Arranged between each pair of bearings 5 is a tensioning bearing 7 which, due to the bracing force 7.1', braces the bearings Sand 7 free of play in circumferential direction 9. The bearing 7 is arranged in the cylinder 1.1 to be displaceable in the circumferential direction thereof.

The illustrated bending line 1.4.3 of the shaft 1.4 results from the bracing force 7.1' in the circumferential direction.

Figure 5 shows a section according to Figure 4 of the shaft 1.4 in the bearing 7 with gripper 1.5 opened. The bracing force 7.1' acting in circumferential direction is present centrally at the gripper shaft 1.4 and the tensioning bearing 7.

The shaft 1.4 and the bearing 7 with the gripper 1.5 closed is illustrated in Figure 6. The bracing force 7.1' in circumferential direction 9 is arranged centrally at the bearing 7. The roller lever bearing force 4.2 and gripper bearing force 5.1 are present centrally at the shaft 1.4 perpendicularly to the bracing force 7.1'.

The resultant bearing force 8', present at the shaft 1.4 and illustrated in Figure 6, results from the forces illustrated in Figures 1,2,3 and 4.

Through the additional bracing of the shaft 1.4 in circumferential direction of the cylinder 1.1, the forces present at the shaft 1.4, the gripper bearing force 5.1 and the resultant roller lever bearing force 4.2 move the shaft 4.1 only slightly in the bearing 5 and thus to a large extent prevent a change in position of the grippers 1.5 in circumferential direc tion.

Reference is made to the aforesaid German application WP B 41 F/246 658/0 to such an extent as may be necessary to facilitate understanding of any further details of the preferred embodiment.

Claims

1. A sheet handling apparatus comprising a rotary sheet conveying cylinder, a shaft mounted in the cylinder by a plurality of bearings, and a plurality of sheet gripper members mounted on the shaft and cooperable with sheet engaging means to grip sheets to be conveyed by the cylinder, the bearings comprising at least two spaced main bearings and a stressing bearing disposed between the two main bearings and arranged to be displaceable in the circumferential direction of the cylinder.

2. A sheet handling apparatus substantially as hereinbefore described with reference to the accompanying drawings.