GB2084514A - Tripping and adjustment in rotary printing press - Google Patents

Abstract

A rotary press for printing on metal sheets is equipped with a device to enable the roll gap (N) between a pressure roll (1) and a resilient roll (2) to be adjusted for sheet thickness, and to be retained after tripping of the rolls when no sheets are being fed. Pressure roll (1) is mounted in eccentric bearings and the fine adjustment means includes a screw shaft (8) lockably rotatable by means of a knob (6), and a first (10, 15, 14) and second (17, 18, 20) link mechanisms interconnected by a relay fulcrum shaft (13) so that back and forth movement of the screw shaft (8) is transmitted as the rotary movement of the bearing housing. A third link mechanism (25, 26a, 26b, 24) is actuated by drive shaft (23) in the absence of a sheet to trip the roll (1) by movement of the second link mechanism only. <IMAGE>

Description

SPECIFICATION Improvements relating to rotary presses This invention relates to rotary presses for performing printing operations on metal sheets, and more particularly to a tripping device for use in such a rotary press.

The invention has been devised with the general object of providing a tripping device in which the distance separating the axes of a pressure roll and a resilient roll can be easily, correctly and finally adjusted in order to adjust the gap between the rolls in accordance with the thickness of the metal sheet which is being handled and wherein furthermore the metal sheet can be freed by automatic action to increase the roll gap, with automatic reversion to the previously set roll gap whereupon resetting of the rolls results in reversion to the previously set roll gap.

Hitherto for the purpose of adjusting the roll gap there has been provision for the pressure roll to be directly displaced by means of a turnbuckle or like means. This conventional arrangement however has the disadvantage that it is extremely difficult to maintain the fine adjustment of the roll gap with sufficient precision because of the existence of backlash in the turnbuckle screw thread. Moreover, since the positions of both bearings of the roll have to be adjusted, a considerable amount of time and work is involved in the fine adjustment. Thus there is an impracticably long lapse of time whenever there is a change in the thickness of the metal sheet which has to be printed.

When no metal sheet is passing between the rollers of the rotary press it is necessary to preserve a large gap between the pressure roll and the resilient roll in order to prevent the printing ink from being transferred to the resilient roller. To restart printing it is necessary to re-set the roll so as precisely to reproduce the roll gap which had been previously set.

A preferred embodiment of the invention is hereinafter described by reference to the accompanying drawings, in which: Fig. 1 is a side elevation of a tripping device as attached to a rotary press; Fig. 2 is an enlarged sectional view on line Il-li of Fig. 1; Fig. 3 is a sectional view of locking means; and Fig. 4 is a sectional view of the bearing portion of the pressure roll.

Referring now to the drawings, there are shown in chain dashed lines the pressure roll 1 and the resilient roll 2 of a rotary metal printing press, the resilient roll 2 being mounted so as to be capable of being moved into and out of engagement with the pressure roll 1. Thus supporting axles (Fig. 4) project concentrically from each end surface of the pressure roll 1 and are themselves supported by means of bearings 28a. These bearings 28a are mounted in a bearing housing 27 of circular cross section, the outer circular configuration of which is however offset from the rotation axis of the bearings 28a. This bearing housing 27 is mounted in a frame F for free rotation therein.The arrangement is such that the position of the axis of the pressure roll 1 can be changed as a result of the eccentric rotation of the bearing housing 27 so as to change the distance between the axes of the pressure roll 1 and the resilient roll 2 to permit adjustment of the gap N between these rolls.

The mechanism for effecting fine adjustment of the roll gap N in accordance with the thickness of the metal sheet which is being passed between the rolls, as a result of rotation of the bearing housing 27, and the mechanism for creating the large roll gap N have the following characteristics.

As shown most clearly in Fig. 2, a supporting member 7 fixed to the frame F rotatably carries a knob 6. A locking pin 9a is disposed in a direction perpendicular to the axis of the knob 6 and is adapted to lock and unlock the knob 6 against rotation by operation of a knurled head nut 9. A screw shaft 8 screwed to the knob 6 is adapted to be moved back and forth by a distance corresponding to the screw pitch lead as the knob 6 is rotated. On the other hand, a stand 3 fixed to a lower portion of the frame F carries at its upper end a bearing 4 which in turn supports a shaft 5. A bell crank 10 is rotatably mounted on the shaft 5 and this bell crank is pivotally secured at its one end to the screw shaft 8 by means of a pin 11 whilst its other end is pivotally secured to the upper end of a link rod 15 by means of a pin 12.

Furthermore, the lower end of the link rod 1 5 is pivotally connected by means of a pin 16 to a first arm 14 which in turn is connected to an intermediate relay shaft 1 3. The bell crank 10, link rod 15 and the first arm 14 in combination constitute a first link mechanism.

Coupled to the relay shaft 1 3 at the same radial angle as the first arm 14 is a second arm 17. A second link rod 18 is pivotally connected to this second arm 17 by means of a pin 19. An operating rod 20 coupled by means of a pin 22 to the bearing housing 27 is pivotally connected to the second link rod 18 by a pin 21. This second arm 17, second link rod 18 and the operating rod 20 constituted in combination a second link mechanism.

Pivotally connected to the second link rod 1 8 by means of a pin 26b is a third link rod 25. This third link rod 25 is pivotally connected by means of a pin 26a to a third arm 24 fixed to a drive shaft 23 which is adapted to be rotatably driven by cylinder means (not shown).

The foregoing is a description of a tripping device within the ambit of the invention as claimed. For finally adjusting and setting the gap N between the pressure roll 1 and the roller roll 2 in accordance with the thickness of the metal sheet which is to be handled, the lock pin 9a is turned by the knob 9 to permit the knob 6 to rotate.

Thereafter the knob 6 is rotated in order to cause fine movement of the screw shaft 8 back and forth so that motion is imparted to the second link mechanism through the first link mechanism and the relay shaft 1 3. In consequence the actuating rod 20 causes slight rotation of the bearing 27 in accordance with the amount of feed of the screw shaft 8 so as to change the position of the axis of the pressure roll 1 thereby to effect a fine adjustment of the gap 9. Thereafter the lock pin 9a is brought to the locking position to lock the knob 6 against rotation and thereby fix the adjusted roll gap N.

After this fine adjustment of the roll gap, when there is no metal sheet passing through the roll gap, the cylinder means are energised to actuate the drive shaft 23 which in turn causes swinging of the third arm 24 to the right as viewed in Fig. 1 so as thereby to retract the third link rod 25 in a rearward direction. In consequence, the second link rod 1 8 is rotated around a fulcrum constituted by the pin 19 of the second arm 17, so that the bearing housing 27 is rotated a substantial amount to move the pressing roll away from the resilient roll to form a roll gap N which is much greater than that previously set, to free the rolls.In this state, transfer of the printing ink to the rubber roll 2 is completely avoided so that the attaching of ink to the reverse side of the metal sheet, which may otherwise occur when the metal sheet is made to pass through these gaps, is completely eliminated.

As a metal sheet feed instruction is given, the cylinder is actuated to move the third link rod 25 ahead thereby to reset the second link rod 18 to the starting position. In consequence, the axis of the pressure roll 1 is re-set to the original position thereby to recover the initially set roll gap N.

As has been described above, according to the invention, fine adjustment of the roll gap between the pressure roll and the rubber roll is achieved by eccentric rotation of the bearing housing which is caused by the actions of the screw shaft and the first and second link mechanisms, so that a high precision of fine setting of the roll gap is ensured.

In addition, this setting operation can be easily and promptly made. Therefore, the time required for the preparatory work at each time of change of the thickness of the sheet is much reduced as compared with the conventional device to promote the printing work and to improve the efficiency of the same. In addition, the mechanism for forming the large roll gap operates independently of the first link mechanism connected to the second link mechanism, so that the finally adjusted roll gap can be precisely reproduced without any change to ensure an advantage of high position of the roll gap, and accordingly, an increased utility of the rotary press.

Claims (2)

1. A rotary press for printing upon metal comprising a pressure roll and a resilient roll mounted for linear contact with each other and characterised by a tripping device comprising a bearing housing supporting the bearings of the pressure roller and rotatable in an eccentric manner so as to permit adjustment of the distance between the axes of the pressure roll and the resilient roll, adjustment means for permitting fine adjustment of that distance and including a screw shaft mounted on a frame and movable back and forth as it is rotated by means of a knob, said fine adjustment means being lockable by locking means, a first and second link mechanism by means of which the screw shaft of the fine adjustment means is connected to the bearing housing by way of a relaying fulcrum shaft, so that back and forth movement of the screw shaft is transmitted as the rotary movement of the bearing housing, and a third link mechanism connected to said second link mechanism and adapted to be moved back and forth by cylinder means, whereby the distance is substantially increased as a swinging motion is imparted by the third link mechanism only to said second link mechanism, whereas in the reset position the distance set by the fine adjustment means is retained.

2. A rotary press including a tripping device substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.