Protective device on counter-rotating cylinders

Abstract

The invention relates to a protective device on counter-rotating cylinders of substrate processing machines, with a finger protection element arranged close to the cylinder surfaces, which delimits the access to the cylinder gap formed between the cylinder surfaces, wherein the finger protection element has a bearing block which can be displaced from an initial position and a switch which switches when the bearing block is displaced, and the bearing block is pivotally mounted about a pivot axis extending parallel to the cylinder gap and is supported in an initial position on a first support point and a second support point spaced apart from the first on a bearing element, wherein a force accumulator is formed which exerts a force between the bearing block and the bearing element which counteracts a displacement of the bearing block from the initial position, wherein the vector of the force runs between the support points.

Description

The invention relates to a protective device on opposed cylinders of sheet-processing machines.Such protection devices serve as hand protection in sheet-processing machines, such as printing machines, and prevent the hand of an operator from being pulled in between two cylinders if the latter, during cleaning or maintenance work, for carelessly grasps too deeply into the cylinder gap.DE 297 10 252 U1 describes a guide device for sheet-shaped printing materials in a printing press. The guide device comprises a guide plate, to which a pivotably mounted pneumatic system and, for example, a blow pipe extending over the full width of a sheet guide cylinder is arranged upstream. The baffle plate can be coupled to a protective device which is secured by circuitry for protecting hazardous locations in the region of the sheet guide cylinder. In addition to the above-described guide plate, the guide device comprises a further guide plate which is mounted pivotably and secured by sensors and serves as a switching protection device. The two guide plates are assigned to sheet guide cylinders functioning as transfer drums between a printing unit and a varnishing unit. The transfer drums cannot be set off from one another, but are, as is known, mounted in a fixed position in the machine frame.DE 41 40 413 A1 discloses an apparatus for changing printing plates in offset printing machines. The device comprises guide rollers by means of which a so-called threading function of the printing end of printing plates can be achieved in the final phase of the rotation of the plate cylinder. The guide rollers can be attached to a dedicated cross beam or directly to an inlet guard.According to DE 43 39 344 C1 and DE 44 04 558 A1, a device for the automated changing of printing plates is known in each case, which device comprises a pivotable inlet guard which is designed to protect a cylinder gap formed between an ink applicator roller and a plate cylinder of a printing press.DE 36 13 463 A1 describes a finger protection element which is arranged close to the cylinder surfaces of opposing cylinders. The finger protection element is provided with a guide surface on the side facing the sheet-guiding cylinder. The guide surface extends concave and approximately equidistant to the circumference of the sheet-guiding cylinder.DE 199 40 534 A1 discloses a printing machine having a finger protection device designed as a blow tube. The finger protection device is arranged in the region of a wedge-shaped cylinder gap formed by an impression cylinder together with an adjustable cylinder.DE 197 05 218 A1 discloses a finger protection element which is arranged as a cross member in the danger zone of cylinders running in opposite directions and interacts with a switching sensor for stopping the machine. The finger protection element comprises a flexible profile body having two profile lips arranged facing the cylinder surfaces. A switching sensor is arranged between the profiled lips.DE 44 17 054 A1 relates to a pressing device in the printing unit of a printing press, having a plate cylinder and a blanket cylinder, having a pressing element which can be set on and off the plate cylinder in a pressing direction by means of a drive for pressing a printing plate arranged on the plate cylinder.DE 195 00 586 C2 discloses a safety device on rotary printing presses with a shaft running parallel to a rotating cylindrical component and mounted in side frames and a guard arranged thereon and extending over the width of the component for the hands of the operating personnel.If there is a need in a printing machine for changing the rubber blanket, the rubber blanket must be moved past the printing press in the known solutions by protective devices which are protected by sensors, such as switch strips. The blanket has a surface with only very low slip properties. If contact occurs between the rubber blanket and the switching strip, this is triggered very quickly and the machine stops.The invention is based on the object of providing an alternative protective device on opposed cylinders of sheet-processing machines.It is in particular the object of the invention to provide a protective device on oppositely directed cylinders of sheet-processing machines which ensures a high level of safety of the operator against injuries and avoids an undesired activation of a safety shutdown.The object is achieved according to the invention by the features of claim 1.The advantages which can be achieved with the invention consist in particular in the fact that the assembly of rubber wipes or of plates is facilitated, because the high surface friction coefficient thereof, in particular in the case of rubber wipes, has a less pronounced effect.Accidental contact with the protective device, as can occur during manual insertion or manual change of a blanket or printing plate, no longer in any case leads to a shutdown of the machine or of the drives of the cylinders of the relevant printing unit. As a result, the assembly time can be significantly reduced. On the one hand, the operator no longer has to work with an otherwise required high precision of movement during manual insertion or manual change, in order to avoid undesired contacting of the protective device. On the other hand, the additional working time, which would be required for the renewed activation thereof in the event of an undesired triggering of the shutdown of the machine or of the drives of the cylinders of the relevant printing unit, can be saved.An exemplary embodiment of the invention is illustrated in the drawings and is described in more detail below.The following are shown: FIG. 1 is a schematic illustration of a sheet processing machine; FIG. 2 shows a printing unit of a sheet-processing machine in a perspective illustration; FIG. 3 shows a printing unit of a sheet-processing machine in a sectional illustration; FIG. 4 shows a sectional view of a protective device on a sheet-processing machine; FIG. 5 shows a printing unit of a sheet-processing machine in a further illustration; FIG. 6 shows a bearing block and a bearing element of a protective device on a sheet-processing machine in a schematic illustration; FIG. 7 shows a bearing block and a bearing element of a protective device on a sheet-processing machine in a first state; FIG. 8 shows a bearing block and a bearing element of a protective device on a sheet-processing machine in a second state; FIG. 9 shows a side view of a protective device on a sheet-processing machine; FIG. 10 shows details of a protective device on a sheet-processing machine in a sectional illustration.The invention is described below using the example of a printing press, for example a sheet-fed printing press, in particular an offset sheet-fed printing press, wherein this description is also intended to apply analogously to other substrates, in particular sheets, processing machines, in particular punching machines, and to web-fed end printing machines, in particular offset roller printing machines. An embodiment as a punching machine can have, in particular, the features of a sheet-fed printing press without printing units. The invention also relates to punching machines which do not operate on a rotary principle and are designed as so-called flat bed punches.In a preferred embodiment, the sheet-processing machine can be designed as a sheet-mechanically processing, e.g. embossing, cutting or in particular punching, machine having one or more units that mechanically process the sheets, e.g. having at least one punching or embossing unit or a break-out unit.In an advantageous development of the machine, this machine can also be designed in the manner of a hybrid machine as a sheet, mechanically processing machine having at least one punching or embossing unit and additionally at least one printing unit arranged upstream of the punching or embossing unit in the substrate or transport path. The product delivery device, for example stack delivery device of such a machine, can also be designed for delivery of containers formed from sheets.The sheet-fed printing press preferably comprises a feed system, also referred to as feeder 07, for printing materials, in particular substrates. Substrates are understood to mean, in particular, sheet-shaped workpieces made of paper, cardboard, cardboard, corrugated cardboard, plastic or the like, which are preferably printable or printed. The sheet-like substrates are present in the feeder 07 of the sheet-fed printing press as stacks and are separated from the latter and fed to the units of the sheet-fed printing press downstream of the feeder 07 via an acceleration system 25 and moved in a feed direction T through the units of the machine. The sheet-fed printing press comprises at least one, preferably a plurality of, printing units 06. The printing units 06 each comprise in particular a cylinder 40, e.g. printing cylinder 40 and a cylinder 41, preferably sheet guide cylinders 41 designed as transfer drum 41. a cylinder 42 carrying a blanket, in particular blanket cylinder 42, is assigned to the printing cylinder 40 and a cylinder 43 carrying a printing plate, in particular plate cylinder 43, is assigned to the latter in turn.The plate cylinder 43 has a plate cylinder channel arranged axially to the plate cylinder 43, in which tensioning rails are arranged for receiving the front edge of the printing plate. The blanket cylinder 42 also has a blanket cylinder channel arranged axially with respect to the blanket cylinder 42, in which channel tensioning devices for fixing and tensioning a respective blanket are arranged on its front edge and on its rear edge.The plate cylinder 43 is in contact with an inking unit 45 and preferably also a dampening unit.In the printing units 06, the cylinders 40; 41; 42; 43 are mounted via bearing points formed in lateral frame parts.In the printing unit 06, the sheet-like substrate is guided in a manner known per se by the sheet holding systems provided on the printing cylinder 40 and sheet guide cylinder 41, in particular in the form of mechanical front edge grippers, printed in the printing nip formed between the printing cylinder 40 and the blanket cylinder 42 and transferred to the adjoining unit of the sheet-fed printing press, for example in the form of the next printing unit 06. Following the printing unit or units 06 or between the printing units 06, one or more coating units 11 and / or one or more processing units can be formed. The last printing unit 06 or varnishing unit 11 or processing unit in the feed direction T transfers the substrates to the delivery device 09, in which the substrates are deposited to form a stack on a stack carrier which can be lowered to receive the stack. For controlling the sheet-fed printing press, a control station 04 is preferably designed, which can in particular comprise a monitor 01 for displaying machine states and control elements.A cylinder gap is formed between the blanket cylinder 42 and the plate cylinder 43, which roll on each other in opposite directions for the purpose of transferring printing ink from a printing plate arranged on the plate cylinder 43 to the blanket cylinder 42. On the inlet side of the cylinder gap, i.e. on the side on which the lateral surfaces of the blanket cylinder 42 and the plate cylinder 43 move towards one another, a finger protection element 30 is arranged. The finger guard 30 limits access to the cylinder gap formed between the cylinder surfaces.The finger protection element 30 can be used in principle at any point of a sheet-processing machine, in particular a printing machine, at which a cylinder gap is formed between the cylinder surfaces of opposing cylinders 40; 41; 42; 43, which has to be secured against access. In the case of printing presses, numerous hazardous locations formed by cylinder gaps are secured by enclosures and protective grids. For an arrangement of the finger protection element 30, in particular those cylinder gaps are suitable and provided which must be given functionally related accessibility, while the opposing cylinders 40; 41; 42; 43 rotate, although at a reduced speed. This naturally applies in the case of printing presses which are designed as sheet-fed printing presses only for those cylinder gaps at which an arrangement of the finger protection element 30 does not hinder the transport of the sheet-like substrate through the printing press.The finger protection element 30 comprises a displaceable profiled body 05 and a switch 20 which switches when the profiled body 05 is displaced. The profiled body 05 preferably has bearing journals on the end side or is connected to bearing journals. In particular, the bearing pins are rotatably mounted in lateral frame walls 28. The profile body 05 can be formed from a sheet metal structure or an extruded or cast profile or in another way. The profiled body 05 is preferably embodied in one piece. The profile body 05 can also be designed as a finger protection rod. According to a preferred embodiment, the profiled body 05 can also be formed from a plurality of partial elements. In the case of a multi-part design, a first part body can be optimized in its shape, in particular with respect to the access-limiting protective function, and a further second part body connected to the first part body can have a shape optimized with respect to the increase in the bending stiffness. In particular, the second part body or two second part bodies which are not connected to one another but in turn are each connected to the first part body can have a semicircular cross section and can be designed as half rods.The finger protection element 30 has in particular at least one roller 08, preferably a plurality of rollers 08. The at least one roller 08 is mounted so as to be freely rotatable relative to the profiled body 05 via an axis of rotation 23 extending parallel to the cylinder plate. Preferably, the at least one roller 08 is mounted directly on the profiled body 05. The at least one roller 08 can be mounted in receptacles, in particular bearing elements, arranged with the profile body 05. The profiled body 05 preferably extends over the entire length of the cylinders 42; 43 in the direction of their axes of rotation. In the case of the formation of a single roller 08, it extends in particular over the entire length of the cylinders 42; 43 in the direction of their axes of rotation. In the case of the configuration of a plurality of rollers 08, these are preferably mounted rotatably independently of one another. The plurality of rollers 08 can be arranged in particular on a common rotational axis 23 or have mutually aligned rotational axes 23. The profile body 05 can have a respective recess 26 in the region of a respective roller 08.Preferably, the at least one roller 08 or the plurality of rollers 08 are arranged exclusively on the side of the profile body 05 facing the surface of the rubber blanket cylinder 42. The at least one roller 08 or the plurality of rollers 08 can also be arranged exclusively on the side of the profiled body 05 facing the surface of the plate cylinder 43.Further preferably, the at least one roller 08 is arranged on the side of the profile body 05 facing the surface of the blanket cylinder 42 and at least one further roller 08 is arranged on the side of the profile body 05 facing the surface of the plate cylinder 43.Preferably, the at least one roller 08 or all rollers 08 have lateral surfaces which consist of a compressible material.Further preferably, the profile body 05 has an actuating element 10 which can be pivoted or rotated in various directions from an initial position. The profile body 05 can also be connected to an actuating element 10 of this type. The actuating element 10 is preferably constructed in the manner of a disk or a flange and has a further cutout 22. A switching contact 27 formed on the switch 20 can engage in the recess 22. The actuating element 10 and the switching contact 27 are constructed and associated with one another in such a way that, when the actuating element 10 is pivoted or rotated, the switch 20 switches independently of the direction of the pivoting or rotation.The finger protection element 30 preferably has a bearing block 02 that can be displaced from an initial position and a force accumulator 15. The bearing block 02 is mounted pivotably about a pivot axis extending parallel to the cylinder plate.In its initial position, the bearing block 02 is supported on a first and a second support point 21; 13, spaced apart from the first, on a bearing element 18.The energy accumulator 15 exerts a force between the bearing block 02 and the bearing element 18. The force is directed in particular at right angles to the pivot axis and acts on the bearing block 02 at a point of application. The force holds the bearing block 02 in its initial position in the absence of other larger forces and accordingly counteracts a displacement of the bearing block 02 from the initial position. The energy accumulator 15 is arranged between the bearing block 02 and the bearing element 18 in such a way that the vector of the force runs between the supporting points 21; 13.The first support point 21 is preferably formed by a first support element 12 which is formed on the bearing block 02 or is connected thereto and engages in a first jaw 16 formed on the bearing element 18. The first support element 12 can be a cylinder pin.The second support point 13 preferably has a similar structural structure to the first support point 21 and can be formed by a second support element 14 formed on the bearing block 02 or connected thereto, which engages in a second jaw 17 formed on the bearing element 18. The second support element 14 can also be a cylinder pin.The bearing element 18 can have a preferably oval inner recess in which the energy store 15 can be arranged. The energy store 15 is preferably a tension spring. The tension spring is in particular hooked with its one end into a hook formed in the recess and engages with its other end on the bearing element 18, preferably centrally with respect to the latter.Preferably, the vector of the force in the initial position of the bearing block 02 runs centrally between the first support point 21 and the second support point 13.Further preferably, the vector of the force in the initial position of the bearing block 02 runs eccentrically between the first support point 21 and the second support point 13. The ratio of the magnitude of the forces in different directions corresponds to the ratio of the shortest distance of the supporting points 21; 13 to the vector of the force between the supporting points 21; 13.The bearing block 02 and the bearing element 18 are arranged so as to be constructed in such a way that the bearing block 02 is supported outside its initial position only on one of the two support points 21; 13. In other words, the bearing block 02 is supported at the same time exclusively in its initial position at both support points 21; 13.Accordingly, the bearing of the bearing block 02 is configured such that an external force exerted on the bearing block 02 in the vicinity of the one cylinder 42; 43 or a component connected to the bearing block 02 lifts the bearing block 02 from the first support point 21, and an external force exerted on the bearing block 02 in the vicinity of the other cylinder 42; 43 or a component connected to the bearing block 02 lifts the bearing block 02 from the second support point 13.The bearing block 02 is connected to the profiled body 05 directly or via interposed structural elements, preferably in a fixed manner, in particular in a rotationally fixed manner. Instead of a bearing block 02, a plurality of bearing blocks 02 can also be formed and connected to the profiled body 05. Preferably, an individual bearing block 02 is formed and connected to the profile body 05 in the vicinity of a frame wall 28, i.e. in relation to the extension of the profile body 05 in the direction of the cylinder plate of the opposing cylinders 42; 43, eccentrically to the profile body 05.A pivoting of the bearing block 02 is equal to a pivoting or rotation of the profile body 05 connected to the force transducer 02 about the pivot axis extending parallel to the cylinder plate between the oppositely directed cylinders 42; 43.The bearing element 18 is pivotably mounted at a frame point 19 via a device for length compensation. The device for compensating for length compensates the distance by which the bearing element 18 is displaced when the bearing block 02 is displaced from its initial position.The bearing element 18 can be pivotably mounted at a frame point 19 via a device for length compensation, in particular an elongated hole 24.List of reference characters01 Monitor 02 Bearing block 03-04 Guide stand 05 Profiled body 06 Printing unit 07 Feeder 08 Roller 09 Delivery 10 Actuating element 11 Varnishing unit 12 Supporting element, first 13 Supporting point, second 14 Supporting element, second 15 Energy store 16 Jaw, first 17 Jaw, second 18 Bearing element 19 Frame point 20 Switch 21 Supporting point, first 22 Cutout, further 23 Axis of rotation 24 Elongated hole 25 Acceleration system 26 Cutout 27 Switching contact 28 Frame wall 29-30 Finger protection element 31-32-33-34-35-36-37-38-39-40 Cylinder, printing cylinder 41 Cylinder, sheet guide cylinder, transfer drum 42 Cylinder, blanket cylinder 43 Cylinder, plate cylinder 44-45 Inking unit T Feed direction

Claims

A protection device on oppositely directed cylinders (42; 43) of substrate processing machines, comprising a finger protection element (30) arranged close to the cylinder surfaces and limiting access to the cylinder gap formed between the cylinder surfaces, wherein the finger protection element (30) comprises a bearing block (02) displaceable from a starting position and a switch (20) switching upon displacement of the bearing block (02), and the bearing block (02) is mounted pivotably about a pivot axis extending parallel to the cylinder plate and in a starting position on a first and a second support point (21 spaced apart from the first; 13) is supported on a bearing element (18), wherein a force accumulator (15) is formed which exerts a force between the bearing block (02) and the bearing element (18), said force counteracting a displacement of the bearing block (02) from the initial position, wherein the vector of the force runs between the supporting points (21; 13).Protective device according to claim 1, characterised in that the bearing block (02), outside its initial position, is supported only on one of the two support points (21; 13).Protective device according to claim 1 or 2, characterised in that the first support point (21) is formed by a first support element (12) formed on the bearing block (02) or connected thereto, which engages in a first jaw (16) formed on the bearing element (18), and / or in that the second support point (13) is formed by a second support element (14) formed on the bearing block (02) or connected thereto, which engages in a second jaw (17) formed on the bearing element (18).Protective device according to claim 1, 2 or 3, characterised in that the vector of the force in the initial position of the bearing block (02) runs centrally between the first support point (21) and the second support point (13).Protective device according to claim 1, 2 or 3, characterised in that the vector of the force in the initial position of the bearing block (02) runs eccentrically between the first support point (21) and the second support point (13).The protection device according to claim 1, 2, 3, 4 or 5, characterized in that the bearing of the bearing block (02) is configured such that an external force exerted in the vicinity of the one cylinder (42; 43) on the bearing block (02) or a component connected to the bearing block (02) lifts the bearing block (02) from the first support point (21) and an external force exerted in the vicinity of the other cylinder (42; 43) on the bearing block (02) or a component connected to the bearing block (02) lifts the bearing block (02) from the second support point (13).Protective device according to claim 1, 2, 3, 4, 5 or 6, characterised in that the energy store (15) is a tension spring.Protective device according to claim 1, 2, 3, 4, 5, 6 or 7, characterised in that the bearing element (18) is pivotably mounted at a frame point (19) via a device for length compensation, in particular an elongate hole (24).Protection device according to claim 1, 2, 3, 4, 5, 6, 7 or 8, characterised in that the finger protection element (30) comprises a profile body (05) which extends over the entire length of the cylinders (42; 43) in the direction of their axes of rotation, wherein the profile body (05) is connected indirectly or directly to the bearing block (02).The protection device according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, characterized in that the finger protection element (30) comprises at least one roller (08), wherein the at least one roller (08) is mounted on a or the profile body (05) so as to be freely rotatable via an axis of rotation (23) extending parallel to the cylinder plate.Protective device according to claim 10, characterised in that a plurality of rollers (08) rotatable independently of one another are arranged on one or the axis of rotation (23) or have axes of rotation aligned with one another.Protective device according to claim 10 or 11, characterised in that a plurality of rollers (08) are formed and one or the profile body (05) has a respective recess (26) in the region of a respective roller (08).Protective device according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, characterised in that one or the profile body (05) is formed as a finger protection rod.

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