GB1586446A

GB1586446A - Electrically driven offset printing or duplicating machines

Info

Publication number: GB1586446A
Application number: GB23222/78A
Authority: GB
Original assignee: Rotaprint GmbH
Current assignee: Rotaprint GmbH
Priority date: 1977-05-27
Filing date: 1978-05-26
Publication date: 1981-03-18
Also published as: IT1095649B; DE2724135B2; IT7823751A0; JPS5654230B2; DE2724135A1; FR2391850A1; FR2391850B1; DE2724135C3; JPS5426103A

Description

(54) IMPROVEMENTS RELATING TO ELECTRICALLY DRIVEN OFFSET PRINTING OR DUPLICATING MACHINES (71) We, ROTAPRINT GMBH a German Company of Reinickendorfer Strasse, 46, 1000 Berlin 65 Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be grated to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to electrically driven off-set printing or duplicating machines and in particular to a mechanism for the manual adjustment of the rotary position of the shaft mounted retating parts of such machines.

In off-set printing or duplicating machines, there are various different types of operation when the machine is not printing a continuous run, and these types of operation can be distinguished by the machine speed per minute and type of drive, depending upon the operation to be carried out, e.g. clamping the plate, locating, inking, proofing and continuous printing, washing, trial running, and so on. For certain types of operation it is also necessary for the operator manually to carrye out partial or multiple machine cycles in a forward or reverse direction alternately from any desired zero position of the machine.

Prior art machines for off-set printing or duplication frequently have a crank or handwheel for this purpose. The crank or handwheel may be moved manually, either directly or possibly through a reduction gear in order to reduce the torque required, in order to adjust the rotating parts of the machine. For a continuous run, the crank must be separated from the rotating parts of the machine by a safety clutch, although in some cases the handwheel may be allowed to rotate with the machine. In machines having better operating facilities, an electrical inching system is frequently used, i.e.

the required partial or multiple number of machine cycles is carried out by the electrical drive by actuating a forward or reverse inching button.

The disadvantage of the known type of inching mechanism over a conventional crank or handwheel is that the operator's hand actuating the inching button will not immediately sense the progress of the movement in the machine cycle. The operator must also be expected to have a fairly slow and varying reaction to the change from forward running to reverse running or viceversa, and on the change from start to stop, so that he will find it practically impossible accurately to adjust or stop the machine at the required point without repeated correction inching. On the other hand, the advantage of the inching mechanism is that the operator does not have to apply any unnecessary force, because the machine is moved via motor power.

The object of this invention is to give the user of motor-driven off-set printing and duplicating machines the advantage of the handwheel or handcrank when the machine is not printing a continuous run, i.e. directly associate the angle of rotation of a handwheel to the angle of rotation of the rotating parts of the machine, while at the same time offering the advantages of a machine with an inching mechanism.

The improved mechanism of this invention comprises a handwheel which is disposed on the input shaft of a planetary reduction gear, of which the output shaft is the shaft of the said rotating parts, and the planet carrier is lockable against rotation, the input shaft being divided into an inner and an outer part arranged for limited relative rotation from a spring-biassed middle portion, and two electrical switches which are selectively and manually operable by the said relative rotation and are arranged to effect forward or reverse running of the machine at a crawl speed.

The. mechanism is so constructed that during normal running of the machine (continuous printing) the handwheel performs no rotary movement. If the handwheel is rotated either intentionally or unintentionally during motor-driven machine running, it does not trigger off any functions.

While the machine is stationary in any zero position, the handwheel is connected to the rotating parts of the machine via an overload separating system. On a slow rotary movement of the handwheel in either direction of rotation by the operator, the machine driven by motor power follows at a predetermined crawl speed at the same angular relationship as, and in the direction of rotation of, the handwheel. If the handwheel speed is in advance of the machine crawl speed, an overload separating system is triggered and does not change the machine speed. Nor does it increase a function-dependent minima active advance in the angles of rotation of the handwheel and the machine. The overload separating system also prevents the parts of the gearing from being damaged if the handwheel is rotated with force. After the rotary movement of the handwheel has stopped, an immediate machine stop follows automatically. The machine immediately follows any uniform rotary movement of the handwheel or a rapid forward and reverse change of direction.

One embodiment of this invention will be described with reference to the accompanying drawings wherein: Figure 1 is a perspective general view of a mechanism according to the invention; Figure 2 is an axial section through the mechanism of Figure 1; Figure 3 is a section on the line EF in Figure 2, and Figure 4 is a section on the line CD in Figure 2.

Figures 1 and 2 show an embodiment of the mechanism according to the invention.

A bearing bush 41 is mounted in the frame 50 of the off-set printing machine and carries a shaft 4 via rolling bearings 40, 40'.

Drive gearwheels 1 and 2 are provided on shaft 4 and are secured to the shaft 4 by means of a tapering pin or key. The gearwheels 1, 2 establish the connection to the rotating parts of the printing machine and are therefore part of the impression cylinder drive.

A handwheel 12 is mounted on the extreme right-hand end of the shaft 4 so as to be rotable relatively to the latter. To this end, a first or inner shaft portion 43 in the form of a sleeve is connected to the handwheel and is mounted rotatably on the shaft 4 by means of a needle bearing 33 and a ball bearing 34. A shorter second or outer shaft portion 42 in the form of a sleeve is mounted rotatably on the left-hand end of the inner sleeve 43 in Figure 2 and is so connected to the first portion 43 (in the manner to be described hereinafter) that a limited relative movement between the two shaft portions is possible, while they assume a normal position to one another when not subjected to loads.

A gearwheel 26 bolted to the shaft portion 42 is provided at the left-hand end of the sleeve 42 and concentrically thereof and meshes with a planetary gear 7, which is rigidly connected to another planetary gear 6 via a shaft 8. The common rotable shaft 8 is mounted on a planet carrier which is constructed in the form of a detent disc 5, which is mounted for free rotation on the shaft 4 by means of a rolling bearing 35.

Gearwheel 6 meshes with teeth 3 on the shaft 4, if required via an intermediate gearwheel 9 mounted on the planet carrier or detent disc 5.

The connection between the two shaft sleeves 42, 43 mounted on the shaft is provided as described below. A disc 10, which also acts as a brake disc, is bolted to the outer sleeve 42. A second disc 11 operating as a detent disc is fixed concentrically on the inner sleeve 43, the discs 10 and 11 being axially spaced a small distance.

A control pin 17 is screwed into the disc 11 and engages in a borehole 18 which has a larger diameter than the pin. Borehole 18 thus determines the maximum possible angular off-set between the brake disc 10 and the detent disc 11. The discs 10 and 11 are spring biassed into a specific relative position to one another, and in this position the control pin 17 is situated centrally in the borehole 18. This effect is achieved by means of a detent roller 13 disposed on a lever (Figure 1) mounted pivotally on the brake disc 10 and tensioned by a spring 14.

Roller 13 engages in a detent groove 27 in the disc 11 so that the two discs 10, 11 are resiliently centred in an initial middle position in relation to one another.

Electrical switches 15, 16 are disposed on either side of the borehole 18 on that surface of the brake disc 10 which faces the detent disc 11. The switch plungers are actuated by the control pin 17 when the latter moves out of its initial middle position. The positions of the switches 15, 16 are transmitted to slip rings 30, 31, 32 from which they are picked off by suitable sliding contacts and transmitted to the machine control system (not shown) which actuates the electric motor drive of the printing machine. It should also be pointed out that the positions of the switches 15, 16 can also be picked off without physical contact.

A bell crank 20 is disposed for rotation about a shaft 19 and its end bears a detent pin 22 adapted to pivot into detent grooves 25 on the detent disc 5. The other end of the bell crank 20 is subject to the action of an electromagnet 24 which, when energized, moves the pin 22 into one of the grooves 25.

A tension spring 28 is so disposed on the bell crank 20 that when the electromagnet is de-energized the bell crank pivots in the opposite direction so that the detent pin 22 is pivoted out of the detent groove 25 and releases the disc 5 for rotation.

The bell crank 20 together with the detent pin 22 and the electromagnet 24 constitute an interlock mechanism which trips in the event of an overload.

A lever 29 is disposed for rotation about the shaft 19 and has a brake facing 21 which is held in permanent contact with the periphery of the brake disc 10 by means of a torsion spring 23.

The mechanism described operates as follows.

When the machine is at rest, i.e. when it is electrically switched off, the electromagnet 24 is also de-energized, so that the tension spring 28 disengages the bell crank 20 and the detent pin 22 fixed thereon from the detent groove 25. If the hand-wheel 12 and hence the detent disc 11 are rotated manually, the braking force of the brake disc 10 being overcome, gearwheel 26 will follow this movement because the detent roller 13 has engaged in the groove 27 of the detent disc 11 and because of the slight clearance of the pin 17 in the borehole 18. Since the gearwheels 26, 7, 6, 9 and 3 either mesh with one another or are interconnected, and since the gearwheels 1 and 2 are stationary, the detent disc 5 rotates at a speed corresponding to the speed of rotation of the handwheel 12. In this condition, therefore, it is impossible to rotate the machine cylinder by rotating the handwheel 12.

When the machine is operated by the electric motor normally for a continuous run, the above description of the mode of operation applies except that the drive wheels 1 and 2 are rotating and the handwheel 12 does not perform a rotary movement because it is stopped by the brake disc 21. Instead, the detent disc 5 rotates at a speed corresponding to the normal machine speed. Rotation of the handwheel while the machine is being driven by the electric motor, the braking force of the brake disc 10 then being overcome, only alters the speed of the detent disc 5. The gearwheels 1 and 2 rotate at the normal high speed conventional for continuous printing.

When the machine is to be set up, i.e.

when the plate is to be secured, located, for inking, washing or for make ready operations, then although the machine is switched on electrically it is initially in the state of rest, i.e. the drive wheels 1 and 2 do not move unless the handwheel 12 is actuated.

In this condition, the detent pin 22 of the bell crank 20 is brought into engagement with-one of the detent grooves 25 of the detent disc 5 by means of the electromagnet 24. Rotation of the detent disc 5 about the shaft 4 is thus no longer possible unless an overload disengages the detent pin 22 from the detent groove 25 in order thus to remove the overload. When the detent pin 22 is engaged, the handwheel can be rotated only to the extent of the clearance of the pin 17 in the borehole 18 until the drive wheels 1, 2 are rotated by the motor drive. The explanation for this is as follows: When the handwheel 12 is turned in relation to the brake disc 10, the spring 14 produces a resilient counteracting pressure by means of the detent roller 13 and groove 27. As soon as the pin 17 comes into contact with the plunger of switch 15 or 16 depending upon the direction of rotation of the handwheel 12, so that the corresponding contact is closed, the motor drive of the printing machine starts the drive wheels 1, 2 in the appropriate direction, at a crawl speed, which is greatly reduced in comparison with the normal speed. Consequently, the brake disc 10 with the switches thereon also rotates in the corresponding direction and, if the handwheel is not advanced further, the rotation of the drive wheels 1, 2 produced by the corresponding switch ends as soon as the control pin 17 disengages from the corresponding switch plunger.

Given suitable dimensions for the individual components of the mechanism, the latter can be so arranged that a specific angle of rotation of the handwheel 12 corresponds to the same angle of rotation of a given rotating part of the printing machine, i.e. the gearwheels 1 and 2.

If the handwheel 12 is rotated at a speed below the off-set machine crawl speed, the corresponding switch plunger is thus disengaged from the control pin 17 by the brake disc 10 leading slightly over the detent disc 11. If, on the other hand, the handwheel is forced at a higher speed than corresponds to the printing machine crawl speed, the detent pin 22 disengages against the force of the electromagnet 24 and the handwheel 12 continues to rotate freely until the overload is removed.

The mechanism according to the invention provides an immediate kinetic relationship between the handwheel 12 and the rotary parts of the printing machine although the latter itself is rotated by its electric motor drive.

WHAT WE CLAIM lS:- 1. A mechanism for the manual adjustment of the rotary position of the shaftmounted rotating parts of an electrically driven off-set printing or duplicating machine, comprising a handwheel which is

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Claims

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25 on the detent disc 5. The other end of the bell crank 20 is subject to the action of an electromagnet 24 which, when energized, moves the pin 22 into one of the grooves 25.

A tension spring 28 is so disposed on the bell crank 20 that when the electromagnet is de-energized the bell crank pivots in the opposite direction so that the detent pin 22 is pivoted out of the detent groove 25 and releases the disc 5 for rotation.

The bell crank 20 together with the detent pin 22 and the electromagnet 24 constitute an interlock mechanism which trips in the event of an overload.

A lever 29 is disposed for rotation about the shaft 19 and has a brake facing 21 which is held in permanent contact with the periphery of the brake disc 10 by means of a torsion spring 23.

The mechanism described operates as follows.

When the machine is at rest, i.e. when it is electrically switched off, the electromagnet 24 is also de-energized, so that the tension spring 28 disengages the bell crank 20 and the detent pin 22 fixed thereon from the detent groove 25. If the hand-wheel 12 and hence the detent disc 11 are rotated manually, the braking force of the brake disc 10 being overcome, gearwheel 26 will follow this movement because the detent roller 13 has engaged in the groove 27 of the detent disc 11 and because of the slight clearance of the pin 17 in the borehole 18. Since the gearwheels 26, 7, 6, 9 and 3 either mesh with one another or are interconnected, and since the gearwheels 1 and 2 are stationary, the detent disc 5 rotates at a speed corresponding to the speed of rotation of the handwheel 12. In this condition, therefore, it is impossible to rotate the machine cylinder by rotating the handwheel 12.

When the machine is operated by the electric motor normally for a continuous run, the above description of the mode of operation applies except that the drive wheels 1 and 2 are rotating and the handwheel 12 does not perform a rotary movement because it is stopped by the brake disc 21. Instead, the detent disc 5 rotates at a speed corresponding to the normal machine speed. Rotation of the handwheel while the machine is being driven by the electric motor, the braking force of the brake disc 10 then being overcome, only alters the speed of the detent disc 5. The gearwheels 1 and 2 rotate at the normal high speed conventional for continuous printing.

When the machine is to be set up, i.e.

when the plate is to be secured, located, for inking, washing or for make ready operations, then although the machine is switched on electrically it is initially in the state of rest, i.e. the drive wheels 1 and 2 do not move unless the handwheel 12 is actuated.

In this condition, the detent pin 22 of the bell crank 20 is brought into engagement with-one of the detent grooves 25 of the detent disc 5 by means of the electromagnet 24. Rotation of the detent disc 5 about the shaft 4 is thus no longer possible unless an overload disengages the detent pin 22 from the detent groove 25 in order thus to remove the overload. When the detent pin 22 is engaged, the handwheel can be rotated only to the extent of the clearance of the pin 17 in the borehole 18 until the drive wheels 1, 2 are rotated by the motor drive. The explanation for this is as follows: When the handwheel 12 is turned in relation to the brake disc 10, the spring 14 produces a resilient counteracting pressure by means of the detent roller 13 and groove 27. As soon as the pin 17 comes into contact with the plunger of switch 15 or 16 depending upon the direction of rotation of the handwheel 12, so that the corresponding contact is closed, the motor drive of the printing machine starts the drive wheels 1, 2 in the appropriate direction, at a crawl speed, which is greatly reduced in comparison with the normal speed. Consequently, the brake disc 10 with the switches thereon also rotates in the corresponding direction and, if the handwheel is not advanced further, the rotation of the drive wheels 1, 2 produced by the corresponding switch ends as soon as the control pin 17 disengages from the corresponding switch plunger.

Given suitable dimensions for the individual components of the mechanism, the latter can be so arranged that a specific angle of rotation of the handwheel 12 corresponds to the same angle of rotation of a given rotating part of the printing machine, i.e. the gearwheels 1 and 2.

If the handwheel 12 is rotated at a speed below the off-set machine crawl speed, the corresponding switch plunger is thus disengaged from the control pin 17 by the brake disc 10 leading slightly over the detent disc 11. If, on the other hand, the handwheel is forced at a higher speed than corresponds to the printing machine crawl speed, the detent pin 22 disengages against the force of the electromagnet 24 and the handwheel 12 continues to rotate freely until the overload is removed.

The mechanism according to the invention provides an immediate kinetic relationship between the handwheel 12 and the rotary parts of the printing machine although the latter itself is rotated by its electric motor drive.

WHAT WE CLAIM lS:- 1. A mechanism for the manual adjustment of the rotary position of the shaftmounted rotating parts of an electrically driven off-set printing or duplicating machine, comprising a handwheel which is

disposed on the input shaft of a planetary reduction gear, of which the output shaft is the shaft of the said rotating parts, and the planet carrier is lockable against rotation, the input shaft being divided into an inner and an outer part arranged for limited relative rotation from a spring-biassed midde portion, and two electrical switches which are selectively and manually operable by the said relative rotation and are arranged to effect forward or reverse running of the machine at a crawl speed.
2. A mechanism according to claim 1, wherein the planet carrier is lockable by an overload detent system.
3. A mechanism according to claim 1 or claim 2, wherein the middle position of the two parts of the input shaft is brought about by a detent roller which is spring biassed into a detent groove in a detent disc connected to the inner part of the input shaft, which part is in the form of a sleeve.
4. A mechanism according to claim 3, wherein the outer part of the input shaft is in the form of a sleeve and is provided with a brake disc against which a resiliently prestressed brake pad bears.
5. A mechanism for the manual adjustment of the rotary position of the shaft mounted parts of an electrically driven off-set printing or duplicating machine substantially as herein described with reference to the accompanying drawings.