EP0182080B1 - Safety device for rotary printing machines - Google Patents

Abstract

A safety device has pivotally mounted rails for guarding impression cylinder nips in a sheet-fed rotary printing press. The guard rails are pivoted from a guard or safety position during maintenance to a second position away from the impression cylinder during printing to insure that the printed sheets are not smeared by the edges of the guard rails. The guard rails, however, also sense operator contact during maintenance to cause the inching drive of the press to shut off immediately. A hinged access cover or door on the press shields the impression cylinder and cooperating cylinder during printing, and is opened to perform maintenance. Opening of the access cover operates an electrical switch for shutting off the main drive of the press, and the access cover is mechanically connected to the guard rails by a resilient linkage which in turn causes pivoting of the guard rails toward their safety positions. A second electrical switch is operated by the pivoting of the guard rails and shuts off the inching drive in response to operator contact and pivoting of the guard rails in either direction from their safety positions. The resilient linkage also includes abutments limiting the range of pivoting due to operator contact.

Description

The invention relates to a safety device on sheet-fed rotary printing presses, which serves to secure a nip, in particular between the printing cylinder and blanket cylinder, preferably for a five-cylinder printing unit and a smudge-free running of the printing sheet, with pivotable securing plates being provided between a basic position in operation and further positions, which when actuated are provided Park the press and lock electrically to inching.

Such a safety device is known from GB-A-2046175 (DE-C-2 914 152). The safety device is designed in two parts, two differently acting locking plates being pivotally connected to one another via a hinge. In the basic position, both sheet metal parts serve as a sheet guide, the first sheet metal part arranged at the roll outlet being pivoted out of its securing position at the roll gap. The latter prevents the printing sheet end from being smeared during operation at the edge of the first sheet metal part, especially if sheets that tend to smear, e.g. processed from cardboard. To wash the printing cylinder, the first sheet metal part is brought into its securing position in the direction of the printing cylinder by first turning off the second sheet, which enables access to the printing cylinder. At the same time, a switch is operated via a lever that secures the machine against start-up. The disadvantage is that the first sheet metal part placed on the nip cannot touch the machine electrically when touched, so that the safety when washing the printing cylinder is impaired by hand. Furthermore, the machine can only work in reverse jog mode in the safety position, because when the printing cylinder is washed, the second nip in the five-cylinder printing unit is not secured in any other way. The reason for this is that the second plate has to be put down from the nip in order to allow access to the printing cylinder.

A large number of protective devices for securing the entry of a roll nip are already known. e.g. from DE-C-766 210, 1 165 044, 1 561 070, 1 611 238, FR-A-833 280 and 1 579 086. With these devices, the feed side of a nip is secured when the machine comes to a stop when the fuse is touched is or the access to the roller gap is reduced or hindered by resilient sheets that act counter to the feed direction. However, there is the disadvantage that smear-free printed sheets cannot be obtained at the roll outlet, since the fuses cannot be swiveled out of the path of the sheet during operation and cannot be re-activated if maintenance and adjustment work are to be carried out.

From the patent application FR-A-2 247 349 a protective device in the area of the catwalks connecting the printing units of printing presses and the inking units is known, which has covers covering the danger points and interacting with limit switches. However, the covers cannot serve as a sheet guide.

The invention has for its object to provide a safety device on sheet-fed rotary printing presses in which electrically switching, preferably L-shaped locking plates arranged parallel to the roller axes, in particular between the rubber and impression cylinders, in the danger zone ensure timely lubrication-free printed sheets from the securing position to a basic position can be swung out during operation.

This object is achieved by the characterizing features of the first claim. Further developments of the invention are contained in the subclaims, drawing and the description.

• Fig. 1 zeigt eine Seitenansicht der erfindungsgemäßen Sicherungseinrichtung.
• Fig. 2 zeigt die Seitenansicht nach Fig. 1 unter besonderer Berücksichtigung der Sicherungsstellung.

This makes it possible to achieve both unhindered access for washing the printing cylinder and, at the same time, increased security at the confluence of the cylinders, in particular the two intake points between the printing and rubber cylinders of a five-cylinder arrangement, without the printing sheets being able to smear on the edges of the fuses during operation . In addition, the machine does not need to be electrically locked to limit or reverse jog mode and the ease of use when working on several cylinders at the same time is increased. In one embodiment, the invention will be explained in more detail with reference to the drawing.

• Fig. 1 shows a side view of the safety device according to the invention.
• Fig. 2 shows the side view of FIG. 1 with special consideration of the securing position.

In a sheet-fed rotary printing press, two blanket cylinders 2, 3 are arranged around a printing cylinder 1 in a five-cylinder printing unit.

Between the rubber cylinders 2, 3 and the pressure cylinder 1, L-shaped locking plates 5, 6 are attached in front of the danger zone at the confluence of the cylinders 1, 2 and 1, 3 on pivoting levers 7, 8, which are mounted in pivot points 9, 10 on the machine stand . Switching bodies are arranged so as to be rotatable about a guide element 13. These switching bodies have, as common components, in addition to the connecting rods 11, 12 and the guide element 13, a switching rod 14, on which pressure springs 25, 26, spacer tubes 27, 28 and stops 29, 30 are arranged. One limit switch 16, 18 each is coupled to an associated switching segment 15, 17. The switching segments 15, 17 mounted on pivot points 19, 20 on the machine stand have a groove on the circumference into which rollers 21, 22 protrude, which interact with the switching plungers 23, 24 of the limit switches 16, 18. The guide element 13 has a bore , by which the shift rod 14 is passed through. The compression springs 25, 26 arranged on the shift rod 14 in spacer tubes 27, 28 endeavor to keep the guide element 13 and thus the locking plates 5, 6 in the central position, which corresponds to the locking position for the touch circuit.

When washing the cylinder, in particular the printing cylinder 1, an outer protective cover 4 is folded up (FIG. 1). This enables access to the printing cylinder 1. By folding up the outer protective cover 4, the first switching body 5 to 8, 11 to 15, including the spring member 25 to 30, is actuated, whereby the pivot levers 7, 8 with locking plates 5, 6 from the parking lock in the basic position in operation (dashed in Fig. 1 drawn) in the electrically switching middle position, the safety position. At the same time, the limit switches 16, 18 are actuated via the switching segments 15, 17, as a result of which a safety circuit is used to switch from machine "commissioning" to machine "stop". In the end position, the roller 21 of the switching plunger 23 falls into the groove of the switching segment 15, so that the lower switch 16 is free for a touch circuit in which typing and a creep speed are still possible.

Assuming when washing the printing cylinder 1, the operator's hand approaches one of the two nips between the printing cylinder 1 and the blanket cylinder 2 or 3 and bumps against the locking plates 5, 6 fastened on pivoting levers 7, 8, and the first switching body with the parts 5 to 8 , 11 to 15 on the guide element 13 against the compression springs 25, 26 pivotally supported in the pivot point 20, with the distance tubes 27, 28 and stops 29, 30 on the shift rod 14 of the switching path in two end positions around the central position, ie the securing position is limited (s, Fig. 2). The pivoting causes an immediate actuation of the limit switch 16 by the roller 21, whereby the power supply to the drive motors is interrupted.

By closing the outer protective cover 4 after washing or other maintenance and adjustment work, the locking plates 5 are put down from the locking position into the basic position, in which lubrication-free printed sheets are guaranteed during operation. At the same time, the limit switch 18 is free again for normal operation.

Reference symbol list

• 1 impression cylinder
• 2 rubber cylinders
• 3 "
• 4 outer protective cover
• 5 locking plate
• 6 "
• 7 swivel levers
• 8th "
• 9 pivot point on the machine stand
• 10 "
• 11 connecting rod
• 12 "
• 13 guide element
• 14 shift rod
• 15 switching segment
• 16 limit switches
• 17 switching segment
• 18 limit switches
• 19 Pivotal point on the machine stand
• 20 "
• 21 roll
• 22 roll
• 23 switching plungers
• 24 "
• 25 compression spring
• 26 "
• 27 spacer tube
• 28 "
• 29 stop
• 30 "

Claims (2)

1. Safety device on sheet fed rotary printing presses which serves for rendering safe a roller nip particularly between impression cylinder (1) and blanket cylinders (2, 3) preferably for a five cylinder printing unit and for smear free running of the printed sheet, wherein safety plates (5, 6) are provided swingable between a base position in operation and further positions which on actuation turn off the printing press and lock it electrically to inching movement, characterised in that a first mechanical switching member (5 to 8, 11 to 15, 25 to 30) is connected in rotationally movable fashion with a second mechanical switching body (4, 17), the switching body (5 to 8, 11 to 15, 25 to 30; 16, 18) has pivoted levers (7, 8) on which L-shaped safety plates (5, 6) are fixed which can be moved to and fro between a base position in operation and an electrically switching middle position, when the base position in operation includes taking out the L-shaped safety plates from the roller nip and the outer protective cover (4) is placed over the roller nip, that furthermore the movement into and out of place of the safety plates (5, 6) and the pivoted lever (7, 8) is controllable by the lifting movement of an outer protective cover 4 and both switching members (5 to 8, 11 to 15, 25 to 30; 4, 17) are electrically coupled via limit switches (16, 18) and a safety circuit.

2. Device according to claim 1 characterised in that the first mechanical switching member (5 to 8, 11 to 15, 25 to 30) is connected with a spring element (25 to 30) which holds the pivoted levers (7, 8) in a centre position, the safety position, between stops (13, 27, 30).

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